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  • 1.
    Ahrén, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Selegård, Linnéa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Klasson, Anna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Skoglund, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, The Institute of Technology.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 8, p. 5753-5762Article in journal (Refereed)
    Abstract [en]

    Recently, much attention has been given to the development of biofunctionalized nanoparticles with magnetic properties for novel biomedical imaging. Guided, smart, targeting nanoparticulate magnetic resonance imaging (MRI) contrast agents inducing high MRI signal will be valuable tools for future tissue specific imaging and investigation of molecular and cellular events. In this study, we report a new design of functionalized ultrasmall rare earth based nanoparticles to be used as a positive contrast agent in MRI. The relaxivity is compared to commercially available Gd based chelates. The synthesis, PEGylation, and dialysis of small (3−5 nm) gadolinium oxide (DEG-Gd2O3) nanoparticles are presented. The chemical and physical properties of the nanomaterial were investigated with Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. The proton relaxation times as a function of dialysis time and functionalization were measured at 1.5 T. A capping procedure introducing stabilizing properties was designed and verified, and the dialysis effects were evaluated. A higher proton relaxivity was obtained for as-synthesized diethylene glycol (DEG)-Gd2O3 nanoparticles compared to commercial Gd-DTPA. A slight decrease of the relaxivity for as-synthesized DEG-Gd2O3 nanoparticles as a function of dialysis time was observed. The results for functionalized nanoparticles showed a considerable relaxivity increase for particles dialyzed extensively with r1 and r2 values approximately 4 times the corresponding values for Gd-DTPA. The microscopy study showed that PEGylated nanoparticles do not activate neutrophils in contrast to uncapped Gd2O3. Finally, the nanoparticles are equipped with Rhodamine to show that our PEGylated nanoparticles are available for further coupling chemistry, and thus prepared for targeting purposes. The long term goal is to design a powerful, directed contrast agent for MRI examinations with specific targeting possibilities and with properties inducing local contrast, that is, an extremely high MR signal at the cellular and molecular level.

  • 2.
    Asplund Persson, Anna
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Zalavary, Stefan
    Linköping University, Faculty of Health Sciences.
    Lindström, Eva
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Whiss, Per A
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Cross-talk between adenosine and the oxatriazole derivative GEA 3175 in platelets2005In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 517, no 3, p. 149-157Article in journal (Refereed)
    Abstract [en]

    We examined the interplay between adenosine and the nitric oxide (NO)-containing oxatriazole derivative GEA 3175 in human platelets. The importance of cyclic guanosine 3′5′-monophosphate (cGMP)-inhibited phosphodiesterases (PDEs) was elucidated by treating the platelets with adenosine combined with either GEA 3175 or the PDE3-inhibitor milrinone. The drug combinations provoked similar cyclic adenosine 3′5′-monophosphate (cAMP) responses. On the contrary, cGMP levels were increased only in GEA 3175-treated platelets. Both drug combinations reduced P-selectin exposure, platelet adhesion and fibrinogen-binding. However, adenosine together with GEA 3175 was more effective in inhibiting platelet aggregation and ATP release. Thrombin-induced rises in cytosolic Ca2+ were suppressed by the two drug combinations. Adenosine administered with GEA 3175 was, however, more effective in reducing Ca2+ influx.

    In conclusion, the interaction between adenosine and GEA 3175 involves cGMP-mediated inhibition of PDE3. The results also imply that inhibition of Ca2+ influx represent another cGMP-specific mechanism that enhances the effect of adenosine.

  • 3.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Frydén, A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Zalavary, S
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Whiss, Per A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Orselius, Kristina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Platelets enhence neutrophil locomotion: evidence for a role of P-selectin1999In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 59, p. 439-450Article in journal (Refereed)
  • 4.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Grenegård, M
    Leucocyte activation by collagen-stimulated platelets in whole blood2002In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 62, no 6, p. 451-462Article in journal (Refereed)
    Abstract [en]

    Interaction between vascular cells plays an important role in the initial phases of the inflammatory process, but the mechanisms responsible for cell-cell communication are not fully understood. In this study, activation of leucocytes and platelets in heparinized whole blood was assessed using lumi-aggregometry. This technique enables simultaneous measurement of aggregation and oxygen radical production by monitoring impedance and luminol-amplified chemiluminescence (CL), respectively. Collagen induced aggregation and CL, depending on dose, and markedly enhanced subsequent aggregation and CL-response triggered by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMet-Leu-Phe). Collagen stimulation of whole blood down- and upregulated the expression of L-selectin and CD11b, respectively. Monoclonal antibodies against sialyl LewisX and P-selectin caused a pronounced inhibition of the oxidative burst, triggered by collagen itself or by a combination of collagen and fMet-Leu-Phe. Furthermore, the Arg-Gly-Asp-Ser(RGDS)-peptide effectively inhibited collagentriggered aggregation and CL, and the subsequent enhancement of the fMet-Leu-Phe-induced responses. This suggests that fibrinogen plays a part in linking platelet GpIIb/IIIa with CD11b on the leucocyte surface. However, neither anti-CD11b nor the PI-peptide (containing the ?-chain motif in fibrinogen that interacts with CD11b) counteracted the stimulatory effects of activated platelets on leucocyte functions. The selectin- and integrin-antagonizing substances were ineffective on the CL-responses induced by fMet-Leu-Phe itself. This study suggests that, through selectin- and integrin-dependent interaction, activated platelets potentiate leucocyte aggregation and oxygen radical production, which might be important for the outcome of inflammatory reactions.

  • 5.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Karlsson, Helen
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Gunnarsson, Patrik
    Östergötlands Läns Landsting, Centre for Medicine, Occupational and Environmental Medicine Centre. Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Skoglund, Caroline
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Elison, Charlotte
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Leanderson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Occupational and Environmental Medicine Centre.
    Lindahl, Mats
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    The periodontal pathogen Porphyromonas gingivalis cleaves apoB-100 and increases the expression of apoM in LDL in whole blood leading to cell proliferation2008In: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 263, no 5, p. 558-571Article in journal (Refereed)
    Abstract [en]

    Objective: Several studies support an association between periodontal disease and atherosclerosis with a crucial role for the pathogen Porphyromonas gingivalis. This study aims to investigate the proteolytic and oxidative activity of P. gingivalis on LDL in a whole blood system by using a proteomic approach and analyze the effects of P. gingivalis-modifed LDL on cell proliferation.

    Methods: The cellular effects of P. gingivalis in human whole blood were assessed using lumi-aggregometry analyzing reactive oxygen species (ROS) production and aggregation. Blood was incubated for 30 min with P. gingivalis, whereafter LDL was isolated and a proteomic approach was applied to examine protein expression. LDL-oxidation was determined by analyzing the formation of protein carbonyls. The effects of P. gingivalis-modifed LDL on fibroblast proliferation were studied using the MTS-assay.

    Results: Incubation of whole blood with P. gingivalis caused an extensive aggregation and ROS-production, indicating platelet and leukocyte activation. LDL prepared from the bacteria-exposed blood showed an increased protein oxidation, elevated levels of apoM and formation of two apoB-100 N-terminal fragments. P. gingivalis-modified LDL markedly increased the growth of fibroblasts. Inhibition of gingipain R suppressed the modification of LDL by P. gingivalis.

    Conclusions: The ability of P. gingivalis to change the protein expression and the proliferative capacity of LDL may represent a crucial event in periodontitis-associated atherosclerosis.

  • 6.
    Bengtsson, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Orselius, Kristina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology.
    Role of the actin cytoskeleton during respiratory burst in chemoattractant-stimulated neutrophils2006In: Cell Biology International, ISSN 1065-6995, E-ISSN 1095-8355, Vol. 30, no 2, p. 154-163Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to clarify the role of the actin cytoskeleton during chemotactic peptide fMet-Leu-Phe (fMLF)-stimulated respiratory burst in human neutrophil granulocytes. Reactive oxygen species (ROS) was measured as luminol-amplified chemiluminescence (CL) and F-actin content as bodipy phallacidin fluorescence in neutrophils treated with latrunculin B or jasplakinolide, an inhibitor and activator of actin polymerization, respectively. Latrunculin B markedly decreased, whereas jasplakinolide increased, the F-actin content in neutrophils, unstimulated or stimulated with fMLF. Latrunculin B enhanced the fMLF-triggered ROS-production more than tenfold. Jasplakinolide initially inhibited the fMLF-induced CL-response, however, caused a potent second sustained phase (>400% of control). Both actin drugs triggered a substantial CL-response when added 5-25 min after fMLF. This was also valid for chemotactic doses of fMLF, where latrunculin B and jasplakinolide amplified the ROS-production 5-10 times. By using specific signal transduction inhibitors, we found that the NADPH oxidase activation triggered by destabilization of the actin cytoskeleton occurs downstream of phospholipase C and protein kinase C but is mediated by Rho GTPases and tyrosine phosphorylation. In conclusion, rearrangements of the actin cytoskeleton are a prerequisite in connecting ligand/receptor activation, generation of second messengers and assembly of the NADPH oxidase in neutrophil granulocytes. © 2005 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.

  • 7.
    Berg, Cecilia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hammarström, Sven
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Herbertsson, Helena
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lindström, Eva
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Ann-Charlotte
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Söderström, Mats
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Platelet-induced growth of human fibroblasts is associated with an increased expression of 5-lipoxygenase2006In: Thrombosis and Haemostasis, ISSN 0340-6245, Vol. 96, no 5, p. 652-659Article in journal (Refereed)
    Abstract [en]

    Proliferation of fibroblasts is vital for adequate wound healing but is probably also involved in different hyperproliferative disorders such as atherosclerosis and cancer. The regeneration of tissue usually starts with coagulation, involving release of mitogenic and inflammatory factors from activated platelets. This study focuses on the role of eicosanoids in the proliferative effects of platelets on human fibroblasts. We show that the phospholipase A2 inhibitor 7,7-dimethyl-5,8-eicosadienoic acid (DMDA), the combined cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor 5,8,11,14-eicosatetraynoic acid (ETYA) and the LOX inhibitor 5,8,11-eicosatriynoic acid (ETI) block the platelet-induced proliferation of serum starved subconfluent human fibroblasts. Anti-proliferative effects were also obtained by specific inhibition of 5-LOX with 5,6-dehydro arachidonic acid (5,6-dAA), whereas the 12-LOX inhibitor cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) did not affect the platelet-stimulated growth of fibroblasts. The expression of 5-LOX was analyzed by reverse-transcriptase-mediated PCR (RT-PCR), Western blotting and HPLC. 5-LOX message and protein was detected in fibroblasts but not in platelets. Incubation with platelets markedly increased, already after one hour, the expression of 5-LOX in the fibroblast culture. The increased 5-LOX activity was associated with an elevated level of the 5-LOX metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) reaching its maximum after 1-2 hours of co-incubation of fibroblasts and platelets. The 5-HETE production was reduced by the inhibitors DMDA, ETYA and ETI. In conclusion, this study suggests that platelet-stimulated proliferation of fibroblasts is mediated by an increased 5-LOX activity, which supports recent findings indicating a crucial role for this enzyme in proliferative disorders such as atherosclerosis. © 2006 Schattauer GmbH, Stuttgart.

  • 8.
    Berg, Cecilia
    et al.
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Trofast, Catarina
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Platelets induce reactive oxygen species-dependent growth of human skin fibroblasts2003In: European Journal of Cell Biology, ISSN 0171-9335, E-ISSN 1618-1298, Vol. 82, no 11, p. 565-571Article in journal (Refereed)
    Abstract [en]

    A growing amount of evidence suggests that reactive oxygen species (ROS), such as hydrogen peroxide and superoxide anion, regulate intracellular signalling and have a role in cell proliferation. In the present study, we show that platelets increase the mitogenic rate in human fibroblasts and that this effect was inhibited by the intracellular antioxidant N-acetyl-L-cysteine (NAC) and the NADPH-oxidase inhibitor diphenyleneiodonium chloride (DPI). The mitogenic effects of platelets were mimicked by the platelet factors platelet-derived growth factor BB-isoform (PDGF-BB), transforming growth factor β1 (TGF-β1) and sphingosine-1-phosphate (S1P). The sphingosine kinase inhibitor DL-threo-dihydrosphingosine (DL-dihydro) abrogated the platelet-induced growth, while antibodies directed against PDGF or TGF-β had modest effects. Exposure of fibroblasts to platelets, PDGF-BB, TGF-β1 or S1P caused an extensive intracellular ROS production, measured as changes in dichlorofluorescein fluorescence. This ROS production was totally inhibited by NAC, pyrrolidinethiocarbamate (PDTC), DPI and apocynin. In conclusion, the results presented are indicative of a crucial role of ROS in the platelet-mediated regulation of fibroblast proliferation.

  • 9.
    Börgeson, Emma
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lönn, Johanna
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bergström, Ida
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences.
    Brodin Patcha, Veronika
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Ramström, Sofia
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Nayeri, Fariba
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Sarndahl, Eva
    University Orebro.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lipoxin A(4) Inhibits Porphyromonas gingivalis-Induced Aggregation and Reactive Oxygen Species Production by Modulating Neutrophil-Platelet Interaction and CD11b Expression2011In: INFECTION AND IMMUNITY, ISSN 0019-9567, Vol. 79, no 4, p. 1489-1497Article in journal (Refereed)
    Abstract [en]

    Porphyromonas gingivalis is an etiological agent that is strongly associated with periodontal disease, and it correlates with numerous inflammatory disorders, such as cardiovascular disease. Circulating bacteria may contribute to atherogenesis by promoting CD11b/CD18-mediated interactions between neutrophils and platelets, causing reactive oxygen species (ROS) production and aggregation. Lipoxin A(4) (LXA(4)) is an endogenous anti-inflammatory and proresolving mediator that is protective of inflammatory disorders. The aim of this study was to investigate the effect of LXA(4) on the P. gingivalis-induced activation of neutrophils and platelets and the possible involvement of Rho GTPases and CD11b/CD18 integrins. Platelet/leukocyte aggregation and ROS production was examined by lumiaggregometry and fluorescence microscopy. Integrin activity was studied by flow cytometry, detecting the surface expression of CD11b/CD18 as well as the exposure of the high-affinity integrin epitope, whereas the activation of Rac2/Cdc42 was examined using a glutathione S-transferase pulldown assay. The study shows that P. gingivalis activates Rac2 and Cdc42 and upregulates CD11b/CD18 and its high-affinity epitope on neutrophils, and that these effects are diminished by LXA(4). Furthermore, we found that LXA(4) significantly inhibits P. gingivalis-induced aggregation and ROS generation in whole blood. However, in platelet-depleted blood and in isolated neutrophils and platelets, LXA(4) was unable to inhibit either aggregation or ROS production, respectively. In conclusion, this study suggests that LXA(4) antagonizes P. gingivalis-induced cell activation in a manner that is dependent on leukocyte-platelet interaction, likely via the inhibition of Rho GTPase signaling and the downregulation of CD11b/CD18. These findings may contribute to new strategies in the prevention and treatment of periodontitis-induced inflammatory disorders, such as atherosclerosis.

  • 10. Herbertsson, H
    et al.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Role of platelets and the arachidonic acid pathway in the regulation of neutrophil oxidase activity2001In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 61, no 8, p. 641-649Article in journal (Refereed)
    Abstract [en]

    The intercellular mechanisms involved in platelet-mediated regulation of neutrophil function remain incompletely understood. This study investigated the role of the arachidonic acid pathway in the modulation of chemoattractant-induced production of oxygen metabolites, measured as luminol-amplified chemiluminescence (CL). We demonstrate that platelets dose-dependently inhibit the CL response in neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine (fMLP). Incubation with eicosatetrayonic acid (ETYA), a combined cyclooxygenase and lipooxygenase inhibitor, dramatically decreased the fMLP-induced CL response in neutrophils, an effect that was further enhanced in the presence of platelets. The separate effects of eicosatriyonic acid (ETI) and indomethacin, specific inhibitors of lipoxygenase and cyclooxygenase, respectively, were significantly lower compared to the action of ETYA. On the contrary, impediment of arachidonic acid release with the phospholipase A2 inhibitor arachidonyl trifluoromethyl ketone (ATK) markedly increased the production of oxygen radicals triggered by fMLP. The addition of exogenous arachidonic acid clearly decreased the fMLP-induced CL response in neutrophils, which further strengthens a downregulating effect of arachidonic acid on oxidase activity. This inhibitory action of arachidonic acid, however, was reversed upon co-incubation with platelets. In conclusion, this study suggests that an accumulation of arachidonic acid, following chemotactic peptide stimulation, turns off neutrophil oxidase activity. Furthermore, platelets may support the synthesis of reactive arachidonic acid metabolites, which modulate oxygen radical production in neutrophils.

  • 11. Johansson, H
    et al.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Pharmacology .
    Platelets and plasma modulate oxygen radical production in neutrophils by mechanisms involving adenosine and arachidonic acid metabolites2001In: Molecular Biology of the Cell, ISSN 1059-1524, E-ISSN 1939-4586, Vol. 12, p. 1415-Conference paper (Other academic)
  • 12.
    Kälvegren, Hanna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Andersson, Johanna
    Grenegård, Magnus
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Platelet activation triggered by Chlamydia pneumoniae is antagonized by 12-lipoxygenase inhibitors but not cyclooxygenase inhibitors.2007In: European Journal of Pharmacology, ISSN 0014-2999, E-ISSN 1879-0712, Vol. 566, no 1-3, p. 20-27Article in journal (Refereed)
    Abstract [en]

    Chlamydia pneumoniae is a respiratory pathogen that has been linked to cardiovascular disease. We have recently shown that C. pneumoniae activates platelets, leading to oxidation of low-density lipoproteins. The aim of the present study was to evaluate the inhibitory effects of different pharmacological agents on platelet aggregation and secretion induced by C. pneumoniae.

    Platelet interaction with C. pneumoniae was studied by analyzing platelet aggregation and ATP-secretion with Lumi-aggregometry.

    Platelet aggregation and ATP-secretion induced by C. pneumoniae was markedly inhibited by the NO-donor S-nitroso-N-acetyl-d,l-penicillamine (SNAP), an effect that was counteracted by the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Pre-treatment of platelets with the 12-lipoxygenase (12-LOX) inhibitors cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) and 5,6,7-trikydroxyflavone (baicalein) completely blocked the activation, whereas the cyclooxygenase (COX) inhibitors 2-acetyloxybenzoic acid (aspirin) and (8E)-8-[hydroxy-(pyridin-2-ylamino)methylidene]-9-methyl-10,10-dioxo-10$l^(6)thia-9-azabicyclo[4.4.0]deca-1,3,5-trien-7-one (piroxicam) had no inhibitory effects. Opposite to C. pneumoniae-induced activation, platelets stimulated by collagen were inhibited by the COX-inhibitors but were unaffected by the 12-LOX-inhibitors. The platelet activating factor (PAF) antagonist Ginkgolide B blocked the C. pneumoniae-induced platelet activation, whereas the responses to collagen were unaffected. Furthermore, the P2Y1 and P2Y12 purinergic receptor antagonists 2'-deoxy-N6-methyladenosine 3',5'-bisphosphate (MRS2179) and N(6)-(2-methyl-thioethyl)-2-(3,3,3-trifluoropropylthio)-beta,gamma-dichloromethylene-ATP (cangrelor) inhibited the aggregation and secretion caused by C. pneumoniae.

    It is well-known that the efficacy of COX inhibitors in the prevention and treatment of cardiovascular disease varies between different patients, and that patients with low responses to aspirin have a higher risk to encounter cardiovascular events. The findings in this study showing that platelets stimulated by C. pneumoniae are unaffected by COX inhibitors but sensitive to 12-LOX inhibitors, may thus be of importance in future management of atherosclerosis and thrombosis.

  • 13.
    Kälvegren, Hanna
    et al.
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Bylin, Helena
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine . Linköping University, Faculty of Health Sciences.
    Leanderson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine . Linköping University, Faculty of Health Sciences.
    Richter, Arina
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Chlamydia pneumoniae induces nitric oxide synthase and lipoxygenase-dependent production of reactive oxygen species in platelets — effects on oxidation of low-density lipoproteins.2005In: Thrombosis and Haemostasis, ISSN 0340-6245, Vol. 94, no 2, p. 327-335Article in journal (Refereed)
    Abstract [en]

    There is increasing evidence that Chlamydia pneumoniae is linked to atherosclerosis and thrombosis. In this regard, we have recently shown that C. pneumoniae stimulates platelet aggregation and secretion, which may play an important role in the progress of atherosclerosis and in thrombotic vascular occlusion. The aims of the present study were to investigate the effects of C. pneumoniae on platelet-mediated formation of reactive oxygen species (ROS) and oxidation of low-density lipoprotein (LDL) in vitro. ROS production was registered as changes in 2´,7`-dichlorofluorescin- fluorescence in platelets with flow cytometry. LDL-oxidation was determined by measuring thiobarbituric acid reactive substances (TBARs). We found that C. pneumoniae stimulated platelet production of ROS.Polymyxin B treatment of C. pneumoniae, but not elevated temperature, abolished the stimulatory effects on platelet ROS- production, which suggests that chlamydial lipopolysaccharide has an important role. In hibition of nitric oxide synthase with nitro-L-arginine, lipoxygenase with 5,8,11-eicosatriynoic acid and protein kinase C with GF 109203X significantly lowered the production of radicals. In contrast, inhibition of NADPH-oxidase with di-phenyleneiodonium (DPI) did not affect the C. pneumoniae induced ROS-production. These findings suggest that the activities of nitric oxide synthase and lipoxygenase are the sources for ROS and that the generation is dependent of the activity of protein kinase C.The C. pneumoniae-induced ROS-production in platelets was associated with an extensive oxidation of LDL, which was significantly higher compared to the effect obtained by separate exposure of LDL to C. pneumoniae or platelets. In conclusion, C. pneumoniae interaction with platelets leading to aggregation, ROS-production and oxidative damage on LDL, may play a crucial role in the development of atherosclerotic cardiovascular disease.

  • 14.
    Kälvegren, Hanna
    et al.
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Fridfeldt (Berggren), Jonna
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Garvin, Peter
    Linköping University, Department of Medicine and Health Sciences, Division of Preventive and Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Wind, Lena
    Leanderson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine . Linköping University, Faculty of Health Sciences.
    Kristenson, Margaretha
    Linköping University, Department of Medicine and Health Sciences, Division of Preventive and Social Medicine and Public Health Science. Linköping University, Faculty of Health Sciences.
    Kihlström, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology . Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Richter, Arina
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences.
    Correlation between rises in Chlamydia pneumoniae-specific antibodies, platelet activation and lipid peroxidation after percutaneous coronary intervention.2008In: European Journal of Clinical Microbiology and Infectious Diseases, ISSN 0934-9723, E-ISSN 1435-4373, Vol. 27, no 7, p. 503-511Article in journal (Refereed)
    Abstract [en]

    We recently showed that Chlamydia pneumoniae activates platelets in vitro, with an associated oxidation of low-density lipoproteins. The aim of this study was to investigate whether C. pneumoniae is released during percutaneous coronary intervention (PCI) and, thereby, causes platelet activation and lipid peroxidation. Seventy-three patients undergoing coronary angiography and following PCI or coronary artery bypass graft (CABG) and 57 controls were included in the study. C. pneumoniae antibodies, serotonin and lipid peroxidation were measured before and 24 h, 1 month and 6 months after angiography. The results show that serum C. pneumoniae IgA concentrations were significantly higher in patients than in the controls. Furthermore, in 38% of the C. pneumoniae IgG positive patients, the C. pneumoniae IgG concentration increased 1 month after PCI. The levels of C. pneumoniae IgG antibodies 1 month after PCI correlated with plasma-lipid peroxidation (r = 0.91, P < 0.0001) and platelet-derived serotonin (r = 0.62, P = 0.02). There was no elevation in the total serum IgG 1 month after PCI. In conclusion, the present results suggest that PCI treatment of coronary stenosis releases C. pneumoniae from the atherosclerotic lesions, which leads to platelet activation and lipid peroxidation.

  • 15.
    Kälvegren, Hanna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Fridfeldt, Jonna
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    The role of plasma adenosine deaminase in chemoattractant-stimulated oxygen radical production in neutrophils2010In: EUROPEAN JOURNAL OF CELL BIOLOGY, ISSN 0171-9335, Vol. 89, no 6, p. 462-467Article in journal (Refereed)
    Abstract [en]

    Objectives: Adenosine deaminase (ADA) has a role in many immunity mediated disorders, such as asthma, tuberculosis and coronary artery disease. This study aims to investigate the ability of plasma ADA to modulate reactive oxygen species (ROS) production in neutrophils, and examine the involvement of adenosine and the cyclic AMP signaling pathway in this process. Methods: Neutrophils were stimulated, in the absence or presence of plasma, with the chemotactic peptide fMLP (formyl-methionyl-leucyl-phenylalanine), and the ROS production was determined with luminol-enhanced chemiluminescence. Activity of ADA was measured spectrophotometrically. Results: Plasma dose-dependently amplified the ROS generation in fMLP-stimulated neutrophils. In parallel, incubation of neutrophils in plasma elevated the total ADA-activity approximately 10 times from 1.3 U/ml to 12 U/ml. Inhibition of ADA, or type IV phosphodiesterases, significantly lowered the plasma-mediated ROS production. Furthermore, the high-affinity adenosine A(1) receptor antagonists DPCPX and 8-phenyltheophylline markedly inhibited the plasma-induced respiratory burst in neutrophils, suggesting an AI receptor-mediated mechanism. Conclusions: This study suggests that plasma ADA amplifies the release of toxic oxygen radicals from neutrophils through a downregulation of the inhibitory adenosine/cAMP-system and an enhanced activation of the stimulatory adenosine A(1)-receptor. This mechanism has probably a crucial role in regulating neutrophil function and in the defence against microbial infections. However, a sustained neutrophil activation could also contribute to inflammatory disorders such as atherosclerosis.

  • 16.
    Kälvegren, Hanna
    et al.
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Majeed, Meytham
    Linköping University, Department of health and environment.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Chlamydia pneumoniae binds to platelets and triggers P-selectin expression and aggregation: A causal role in cardiovascular disease?2003In: Arteriosclerosis, Thrombosis and Vascular Biology, ISSN 1079-5642, E-ISSN 1524-4636, Vol. 23, no 9, p. 1677-1683Article in journal (Refereed)
    Abstract [en]

    Objective - Evidence linking Chlamydia pneumoniae to atherosclerotic cardiovascular disease is expanding. Platelets are considered to play an essential role in cardiovascular diseases, however, so far platelets have not been associated with an infectious cause of atherosclerosis. This study aims to clarify the interaction between Cpneumoniae and platelets and possibly present a novel mechanism in the pathogenesis of atherosclerosis.

    Methods and Results - The effects of C pneumoniae on platelet aggregation and secretion were assessed with lumiaggregometry, and the ability of C pneumoniae to bind to platelets and stimulate expression of P-selectin was analyzed with flow cytometry. We found that Cpneumoniae, at a chlamydia:platelet ratio of 1:15, adheres to platelets and triggers P-selectin expression after 1 minute and causes an extensive aggregation and ATP secretion after 20 minutes of incubation. Inhibition of glycoprotein IIb/IIIa with Arg-Gly-Asp-Ser or abciximab markedly reduced C pneumoniae-induced platelet aggregation. Exposure of C pneumoniae to polymyxin B, but not elevated temperature, abolished the stimulatory effects on platelet activation, suggesting that chlamydial lipopolysaccharide has an active role. In contrast, other tested bacteria had no or only moderate effects on platelet functions.

    Conclusion - Our findings demonstrate a new concept of how C pneumoniae activates platelets and thereby may cause atherosclerosis and thrombotic vascular occlusion.

     

  • 17.
    Kälvegren, Hanna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Skoglund, Caroline
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Helldahl, Christian
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Toll-like receptor 2 stimulation of platelets is mediated by purinergic P2X1-dependent Ca2+ mobilisation, cyclooxygenase and purinergic P2Y1 and P2Y12 receptor activation2010In: Thrombosis and Haemostasis, ISSN 0340-6245, Vol. 103, no 2, p. 398-407Article in journal (Refereed)
    Abstract [en]

    Toll-like receptor 2 (TLR2), which recognise and respond to conserved microbial pathogen-associated molecular patterns, is expressed on the platelet surface. Furthermore, it has recently been shown that the TLR2/1 agonist Pam(3)CSK(4) stimulates platelet activation. The aim of the present study was to clarify important signalling events in Pam(3)CSK(4)-induced platelet aggregation and secretion. Platelet interaction with Pam(3)CSK(4) and the TLR2/6 agonist MALP-2 was studied by analysing aggregation, ATP-secretion, [Ca2+](i) mobilisation and thromboxane B2 (TxB(2)) production. The results show that Pam(3)CSK(4) but not MALP-2 induces [Ca2+](i) increase, TxB(2) production, dense granule secretion and platelet aggregation. Preincubation of platelets with MALP-2 inhibited the Pam(3)CSK(4)-induced responses. The ATP-secretion and aggregation in Pam(3)CSK(4)-stimulated platelets was impeded by the purinergic P2X(1) inhibitor MRS 2159, the purinergic P2Y(1) and P2Y(12) antagonists MRS 2179 and cangrelor, the phospholipase C inhibitor U73122, the calcium chelator BAPT-AM and aspirin. The calcium mobilisation was lowered by MRS 2159, aspirin and U73122 whereas the TxB(2) production was antagonised by MRS 2159, aspirin and BAPT-AM. When investigating the involvement of the myeloid differentiation factor-88 (MyD88) -dependent pathway, we found that platelets express MyD88 and interleukin 1 receptor-associated kinase (IRAK-1), which are proteins important in TLR signalling. However, Pam(3)CSK(4) did not stimulate a rapid (within 10 minutes) phosphorylation of IRAK-1 in platelets. In conclusion, the results show that Pam(3)CSK(4)-induced platelet aggregation and secretion depends on a P2X(1)-mediated Ca2+ mobilisation, production of TxA(2) and ADP receptor activation. The findings in this study further support a role for platelets in sensing bacterial components.

  • 18.
    Lundqvist-Gustafsson, Helen
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Pathology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Activation of the granule pool of the NADPH oxidase accelerates apoptosis in human neutrophils. 1999In: Journal of Leukocyte Biology, ISSN 0741-5400, E-ISSN 1938-3673, Vol. 65, p. 196-204Article in journal (Refereed)
  • 19. Nimeri, G
    et al.
    Majeed, Meytham
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of health and environment.
    Elwing, H
    Öhman, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases . Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rheumatology .
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Pharmacology .
    Oxygen radical production in neutrophils interacting with platelets and surface-immobilized plasma proteins: role of tyrosine phosphorylation2003In: Journal of Biomedical Materials Research, ISSN 0021-9304, E-ISSN 1097-4636, Vol. 67A, no 2, p. 439-447Article in journal (Refereed)
    Abstract [en]

    The interaction between neutrophil granulocytes and platelets is considered to play an important role in the inflammatory process induced by an implanted foreign material. However, the cellular mechanisms involved remain incompletely understood. We used a luminol-dependent chemiluminescence (CL) technique to analyze the generation of reactive oxygen species (ROS) in human neutrophils interacting with different plasma protein-coated surfaces in the presence or absence of unstimulated or stimulated platelets. The role of tyrosine phosphorylation in the regulation of NADPH oxidase activity was evaluated with quantitative fluorescence microscopy and the specific tyrosine kinase inhibitor genistein. We found that the ROS-production is 2 to 3 times higher in neutrophils on immunoglobulin G (IgG)coated surfaces than in cells interacting with albumin- or fibrinogen-coated surfaces. Incubation with superoxide dismutase and catalase revealed that about 45% of the ROS was released extracellularly on IgG surfaces whereas corresponding values were 90% and 85% in neutrophils interacting with albumin and fibrinogen, respectively. The presence of platelets markedly increased the extracellular generation of ROS, mainly in neutrophils. interacting with IgG- or fibrinogen-coated surfaces whereas the intracellular production was only modestly affected. Quantitative fluorescence microscopy of neutrophils stained with FITC-conjugated anti-phosphotyrosine antibodies showed a correlation between tyrosine phosphorylation, cell spreading, and ROS production. Platelets markedly amplified the anti-phosphotyrosine staining on both fibrinogen- and IgG-coated surfaces whereas the low level of tyrosine phosphorylation in neutrophils on albumin-coated surfaces was not further elevated by platelets. Furthermore, the tyrosine kinase inhibitor genistein inhibited both extra- and intracellular ROS production in neutrophils regardless of the presence of platelets. We demonstrate that plasma protein coating and the presence of platelets are crucial for the inflammatory response of adhering neutrophils and that the oxidative response correlates with the extent of tyrosine phosphorylation of proteins in focal contacts. (C) 2003 Wiley Periodicals, Inc.

  • 20. Nimeri, G
    et al.
    Öhman, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Infectious Diseases. Östergötlands Läns Landsting, Centre for Medicine, Department of Infectious Diseases in Östergötland.
    Elwing, H
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    The influence of plasma proteins and platelets on oxygen radical production and F-actin distribution in neutrophils adhering to polymer surfaces2002In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 23, no 8, p. 1785-1795Article in journal (Refereed)
    Abstract [en]

    It is well known that blood cell interactions with artificial surfaces might have deleterious effects on host tissue, however, the mechanisms involved are far from understood. In this study, neutrophil-platelet interaction on uncoated or protein-coated polymer surfaces was investigated. Cell spreading, reorganization of actin filaments and release of oxygen metabolites (measured as luminol-amplified chemiluminescence) were used as criteria for cell activation on positively charged, hydrophilic 1,2-diaminocyclohexane, and negatively charged, hydrophobic hexamethylene-disiloxane. The model surfaces were made by radio frequency plasma discharge polymerization. Neutrophil contact with the uncoated polymers induced a prolonged generation of oxygen radicals. Precoating of the polymer surfaces with human serum albumin (HSA) or fibrinogen, markedly reduced neutrophil activation, whereas coating with human immunoglobulin G (IgG), a well-known opsonin, resulted in significantly higher levels of cell activation. Consequently, protein coating overruled the activating effects of the polymer surfaces. The presence of unstimulated or thrombin-stimulated platelets markedly increased the reactivity of neutrophils against fibrinogen- and IgG-coated surfaces. However, neutrophils remained relatively unreactive in the presence of platelets on HSA-treated surfaces. Comparison of the different types of surfaces used, reveals a correlation between the degree of cell spreading, reorganization of the actin cytoskeleton and the amount of oxygen radicals produced. Our results suggest that the acute inflammatory reaction on a biomaterial surface is highly dependent on the nature and composition of the first adsorbed protein layer and the extent of platelet activation.

  • 21.
    Nylander, Martina
    et al.
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    The periodontal pathogen Porphyromonas gingivalis sensitises human blood platelets to epinephrine2008In: Platelets, ISSN 1369-1635, Vol. 19, no 5, p. 352-358Article in journal (Refereed)
    Abstract [en]

    Recent studies indicate connections between periodontitis and atherothrombosis, and the periodontal pathogen Porphyromonas gingivalis has been found within atherosclerotic lesions. P. gingivalis-derived proteases, designated gingipains activate human platelets, probably through a "thrombin-like" activity on protease-activated receptors (PARs). However, the potential interplay between P. gingivalis and other physiological platelet activators has not been investigated. The aim of this study was to elucidate consequences and mechanisms in the interaction between P. gingivalis and the stress hormone epinephrine. By measuring changes in light transmission through platelet suspensions, we found that P. gingivalis provoked aggregation, whereas epinephrine alone never had any effect. Intriguingly, pre-treatment of platelets with a low, sub-threshold number of P. gingivalis (i.e. a density that did not directly provoke platelet aggregation) resulted in a marked aggregation response when epinephrine was added. This synergistic action was not inhibited by the cyclooxygenas inhibitor aspirin. Furthermore, fura-2-measurements revealed that epinephrine caused an intracellular Ca(2+) mobilization in P. gingivalis pre-treated platelets, whereas epinephrine alone had no effect. Inhibition of the arg-specific gingipains, but not the lys-specific gingipains, abolished the aggregation and the Ca(2+) response provoked by epinephrine. Similar results were achieved by separate blockage of platelet alpha(2)-adrenergic receptors and PARs. In conclusion, the present study shows that a sub-threshold number of P. gingivalis sensitizes platelets to epinephrine. We suggest that P. gingivalis-derived arg-specific gingipains activates a small number of PARs on the surface of the platelets. This leads to an unexpected Ca(2+) mobilization and a marked aggregation response when epinephrine subsequently binds to the alpha(2)-adrenergic receptor. The present results are consistent with a direct connection between periodontitis and stress, and describe a novel mechanism that may contribute to pathological platelet activation.

  • 22.
    Sjöwall, Christoffer
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Skogh, Thomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    CRP and anti-CRP autoantibodies in systemic lupus erythematosus.2005In: Current rheumatology reviews, ISSN 1573-3971, Vol. 1, p. 81-89Article in journal (Refereed)
  • 23.
    Sjöwall, Christoffer
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Wetterö, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Skogh, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, The Institute of Technology. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Solid-phase classical complement activation by C-reactive protein (CRP) is inhibited by fluid-phase CRP-C1q interaction2007In: Biochemical and Biophysical Research Communications - BBRC, ISSN 0006-291X, E-ISSN 1090-2104, Vol. 352, no 1, p. 251-258Article in journal (Refereed)
    Abstract [en]

    C-reactive protein (CRP) interacts with phosphorylcholine (PC), Fcγ receptors, complement factor C1q and cell nuclear constituents, yet its biological roles are insufficiently understood. The aim was to characterize CRP-induced complement activation by ellipsometry. PC conjugated with keyhole limpet hemocyanin (PC-KLH) was immobilized to cross-linked fibrinogen. A low-CRP serum with different amounts of added CRP was exposed to the PC-surfaces. The total serum protein deposition was quantified and deposition of IgG, C1q, C3c, C4, factor H, and CRP detected with polyclonal antibodies. The binding of serum CRP to PC-KLH dose-dependently triggered activation of the classical pathway. Unexpectedly, the activation was efficiently down-regulated at CRP levels >150 mg/L. Using radial immunodiffusion, CRP–C1q interaction was observed in serum samples with high CRP concentrations. We propose that the underlying mechanism depends on fluid-phase interaction between C1q and CRP. This might constitute another level of complement regulation, which has implications for systemic lupus erythematosus where CRP is often low despite flare-ups.

  • 24.
    Skoglund, Caroline
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Sjöwall, Christoffer
    Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Skogh, Thomas
    Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Wetterö, Jonas
    Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    C-reactive protein inhibit complement-mediated platelet activation suggesting a protective role in atherogenesis2006In: Atherosclerosis Supplements, ISSN 1567-5688, E-ISSN 1878-5050, Vol. 7, no 3, p. 284-284Article in journal (Other academic)
    Abstract [en]

      Objective: C-reactive protein (CRP) represents a powerful predictor of coro- nary artery disease. However, its physiological role is not fully understood. The binding of CRP to its ligand phosphorylcholine (PC) activates the com- plement system via the classical pathway, although limited to the initial stages, i.e. no membrane attack complex is formed. The aim of this study was to chaxacterize CRP-induced complement activation on PC-coated surfaces, and to investigate the regulatory effects of PC-bound crp on complement induced platelet activation.

    Methods: PC conjugated to keyhole limpet hemocyanin was immobilized to cross-linked fibrinogen on silica particles. Ellipsometry and polyclonal anti- bodies were used to quantify deposition of serum proteins, complement factors and CRP on the surfaces. Washed platelets as well as serum were prepared according to standard protocols. CRP concentrations were measured with a high sensitivity assay. Lumi-aggregometry was used to evaluate the effects of PC-coated particles and CRP on complement-induced platelet aggregation and secretion.

    Results: Serum (5%) induced platelet aggregation and secretion through complement-dependent mechanisms. PC-coated particles antagonized the complement-mediated platelet activation but only if CRP was present. Inter- estingly, we found that a minor elevation of CRR below 5 rag/1 was sufficient to inhibit platelet activation.

    Conclusions: We suggest that CRP bound to PC-expressing ligands, e.g. bacteria or modified low-density lipoproteins in an atherosclerotic lesion, modulate complement activation and thereby prevent a harmful platelet activation.

  • 25.
    Skoglund, Caroline
    et al.
    Linköping University, Department of Medicine and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Wetterö, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    C1q regulates collagendependentproduction of reactive oxygen species, formation of plateletleukocyteaggregates and levels of soluble Pselectinin whole blood2010Manuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Blood platelets are nowadays recognized as cells with immuno‐modulatory properties as they express receptors involved in immunity (e.g. complement‐, toll‐like‐ and Fcγ‐receptors) and release inflammatory mediators. Furthermore, formation of plateletleukocyte aggregates has an important role during inflammatory conditions, e.g. coronary artery disease. We have previously reported regulatory effects of complement protein 1q (C1q) on platelet activation in experimental setups using isolated cells. In the present study we have continued by investigating the effect of C1q on collagen‐induced aggregation and production of reactive oxygen species (ROS), formation of plateletleukocyte aggregates and levels of soluble P‐selectin in whole blood. Impedance measurements showed that C1q, at physiological concentrations, inhibited collageninduced aggregation in whole blood, whereas it potentiated the collagen‐provoked production of ROS in a luminal‐dependent chemiluminescence assay. The potentiation was dependent on platelets, as the effect was not seen when the platelet fibrinogen binding receptor GpIIb/IIIa was blocked by Reopro. Moreover, the formation of large platelet‐leukocyte aggregates in collagen‐stimulated whole blood was inhibited by C1q. This may be explained by the finding that C1q antagonized the collagen‐induced activation, revealed by lowered levels of soluble P‐selectin. In conclusion, C1q may have an important role in regulating platelet activation and associated leukocyte recruitment during vessel wall injury and thus be involved in inflammatory disorders such as coronary artery disease.

  • 26.
    Skoglund, Caroline
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Pharmacology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rheumatology.
    Skogh, Thomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Sjöwall, Christopher
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences.
    C-reactive protein and C1q regulate platelet adhesion and activation on adsorbed immunoglobulin G and albumin2008In: Immunology and Cell Biology, ISSN 0818-9641, E-ISSN 1440-1711, Vol. 86, no 5, p. 466-474Article in journal (Refereed)
    Abstract [en]

    Blood platelets and C-reactive protein (CRP) are both used clinically as markers of ongoing inflammation, and both participate actively in inflammatory responses, although the biological effects are still incompletely understood. Rapidly adhering platelets express receptors for complement factor 1q (C1q) and the Fc part of immunoglobulin G (IgG), and CRP is known to activate/regulate complement via C1q binding, and to ligate FcγRs. In the present study, we used normal human IgG pre-adsorbed to a well-characterized methylated surface as a model solid-phase immune complex when investigating the effects of CRP and C1q on platelet adhesion and activation. Protein adsorption was characterized using ellipsometry and polyclonal antibodies, and human serum albumin (HSA) and non-coated surfaces were used as reference surfaces. Platelet adhesion to IgG and HSA was inhibited by both C1q and CRP. Furthermore, CRP (moderately) and C1q (markedly) decreased the spreading of adhering platelets. The combination of C1q and CRP was slightly more potent in reducing cell adhesion to IgG, and also impaired the adhesion to HSA and non-coated surfaces. Platelet production of thromboxane B2 (TXB2) was also reduced by C1q both in the presence and absence of CRP, whereas CRP alone had no effect on TXB2 production. We conclude that CRP and C1q regulate the behaviour of platelets, and that this may be an important immunoregulatory mechanism during inflammatory conditions. © 2008 Australasian Society for Immunology Inc. All rights reserved.

  • 27.
    Skoglund, Caroline
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Wetterö, Jonas
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    C1q induces a rapid up-regulation of P-selectin and modulates collagen- and collagen-related peptide-triggered activation in human platelets2010In: Immunobiology, ISSN 0171-2985, E-ISSN 1878-3279, Vol. 215, no 12, p. 987-995Article in journal (Refereed)
    Abstract [en]

    Blood platelets are emerging as important immunomodulatory cells, but complement interaction with platelets is not well understood. Several platelet structures have been described as complement protein 1q (C1q) binding receptors, such as C1qRp/CD93 and gC1qR. However, there are conflicting results whether these receptors are C1q binding structures, or even at all expressed on the cell surface. Recently, the collagen-binding integrin alphaIIbetaI was reported to bind C1q on mast cells, and this receptor is also present on platelets. The aim of this study was to further characterize the effects of C1q on platelets, by quantifying the platelet surface expression of P-selectin (CD62P) and monitoring the formation of platelet-neutrophil aggregates. Using flow cytometry, we found that C1q dose-dependently triggered a rapid but moderate and transient up-regulation of P-selectin already within 5s of C1q exposure. Pre-incubation with an antibody directed against gC1qR significantly inhibited (with 57% compared to control) the up-regulation, whereas an antibody towards the alphaIIbetaI-integrin showed no effect. Stimulation with C1q did not change the cytosolic calcium-levels, as measured with the fluorescent ratiometric probe Fura-2, however, a protein kinase C inhibitor (GF109203x) blocked the C1q-induced P-selectin expression. Furthermore, pre-incubation of platelets with C1q diminished both the collagen as well as the collagen-related peptide-induced up-regulation of P-selectin, most evident after 90s of stimulation. This indicates that C1q may regulate platelet activation via the GPVI receptor, which is a novel finding. Moreover, C1q antagonized the collagen-induced formation of platelet-neutrophil aggregates, indicating a reduced interaction between platelet P-selectin and neutrophil P-selectin glycoprotein ligand-1(PSGL-1/CD162). In summary, C1q induces a moderate rapid platelet P-selectin expression, modulates subsequent collagen and collagen-related peptide stimulation of platelets, and inhibits the formation of platelet-neutrophil aggregates. These immuno-regulatory effects of C1q may have a crucial role in innate immunity and inflammation.

  • 28.
    Svensson, Ann-Charlotte B.
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lindström, Eva G.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Platelet-induced 5-LOX activity is associated with ROS-dependent ASMC proliferation2007Conference paper (Refereed)
  • 29.
    Svensson, Ann-Charlotte B.
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Söderström, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lindström, Eva G.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Platelet fragments, like platelets, induce airway smooth muscle cell proliferation through mechanisms dependent on ros and 5-lox2007Conference paper (Refereed)
  • 30.
    Svensson, Ann-Charlotte
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lindström, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Platelets induce airway smooth muscle cell proliferation2005In: Young Investigators Symposium,2005, 2005Conference paper (Other academic)
  • 31.
    Svensson, Ann-Charlotte
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Grenegård, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lindström, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Platelets induce proliferation of airway smooth muscle cells through mechanisms dependent on ROS and 5-LOX metabolites2005In: European respiratory Society Annual Congress,2005, 2005Conference paper (Other academic)
  • 32.
    Svensson Holm, Ann-Charlotte
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Grenegård, Magnus
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lindström, Eva
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    The role of reactive oxygen species and 5-lipoxygenase in platelet-induced airway smooth muscle cell proliferation2006Conference paper (Refereed)
  • 33.
    Svensson Holm, Ann-Charlotte
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Berg, Cecilia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Herbertsson, Helena
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Söderström, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Hammarström, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lindström, Eva
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    5-Lipoxygenase activity is involved in platelet-induced fibroblast proliferation2006Conference paper (Refereed)
  • 34.
    Svensson Holm, Ann-Charlotte
    et al.
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Berg, Cecilia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Herbertsson, Helena
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Söderström, Mats
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Hammarström, Sven
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Lindström, Eva
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    5-Lipoxygenase activity is involved in platelet-induced fibroblast proliferation2006Conference paper (Refereed)
  • 35.
    Wetterö, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, The Institute of Technology.
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bengtsson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    On the binding of complement to solid artificial surfaces in vitro2002In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 23, no 4, p. 981-991Article in journal (Refereed)
    Abstract [en]

    Since the realization of a complement activation capacity by artificial surfaces upon contact with blood, a common belief has evolved that charged nucleophilic surface groups such as amine (–NH2) and hydroxyl (–OH) react with and eventually bind to the internal thioester in complement factor 3 (C3). A covalent amide or ester linkage is thereby supposed to form between C3b and the surface itself. In this report, we present complement surface binding data by null-ellipsometry for two nucleophilic surfaces (–NH2 and –OH), for surfaces with immunoglobulin G (IgG) covalently bound, and for IgG spontaneously pre-adsorbed to hydrophobic silicon. The results reveal that the plasma proteins that were deposited during complement activation became eluted by sodium dodecyl sulfate. Hence the direct covalent binding between C3 and solid nucleophilic surfaces seems to be only of moderate importance, at least during shorter serum incubations. This strongly suggests that the prevalent covalent linkage model between solid artificial surfaces and C3b is not accurate. Instead we suggest a more pronounced role for C3 associations to other adsorbed proteins and/or electrostatic and hydrophobic protein–surface interactions.

  • 36.
    Wetterö, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, The Institute of Technology.
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bengtsson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Interactions between surface-bound actin and complement, platelets, and neutrophils2003In: Journal of Biomedical Materials Research, ISSN 0021-9304, E-ISSN 1097-4636, Vol. 66A, no 1, p. 162-175Article in journal (Refereed)
    Abstract [en]

    Actin exists as globular (G) monomers or polymeric filaments (F) in the cytoplasm of eukaryotic cells, mediating cell morphologic changes and motility. Large amounts of this protein may be released out to the extracellular compartment during tissue injury, but little is known about its role in biomaterial-related inflammation. We immobilized actin to methylated glass, methylated and aminated silicon, and gold model surfaces and studied the subsequent blood serum deposition and complement activation, generation of reactive oxygen species (ROS), and adhesion and aggregation of neutrophils and platelets. Null ellipsometry showed that approximately one monolayer of G-actin can be immobilized onto the model surfaces and that actin in buffer polymerized on top of this by the addition of K+ and Mg2+ ions to form a thicker layer of firmly bound F-actin. After serum incubation, F-actin bound low amounts of anti-complement factor 1q (anti-C1q). Cell responses upon contact with actin-coated surfaces were analyzed by luminol-amplified chemiluminescence, lumi-aggregometry, and fluorescence microscopy. It was shown that surface-triggered aggregation, spreading, and generation of ROS are down-regulated and comparable to the response by adsorbed albumin. However, F-actin on gold surfaces recruited platelets in a C1q-dependent manner. We conclude that in vitro adsorbed actin is a weak complement, platelet, and neutrophil activator, but that F-actin associates with both C1q and platelets. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 162–175, 2003

  • 37.
    Wetterö, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, The Institute of Technology.
    Bengtsson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    C1q-independent activation of neutrophils by immunoglobulin M-coated surfaces2001In: Journal of Biomedical Materials Research, ISSN 0021-9304, E-ISSN 1097-4636, Vol. 57, no 4, p. 550-558Article in journal (Refereed)
    Abstract [en]

    Neutrophil granulocytes are known to rapidly adhere and undergo frustrated phagocytosis upon contact with immunoglobulin and/or complement protein opsonized artificial surfaces. In this study, we examined the relation between serum protein deposition and human neutrophil activation on hydrophobic glass and silicon model surfaces that were coated with immunoglobulin G or M (IgG/IgM), both initiators of the classical complement pathway. Protein adsorption from normal human serum (NHS) was quantified with null-ellipsometry combined with antibody techniques. The neutrophil oxygen radical production was registered by luminol-amplified chemiluminescence (CL) and the morphology, as well as changes in the content of filamentous actin (F-actin), were documented by fluorescence microscopy. Complement factor 3 (C3) bound to both IgG- and IgM-coated surfaces, but surprisingly C1q was found only on IgG-coated surfaces. Both immunoglobulins triggered complement dependent neutrophil activation. However, CL and F-actin accumulation were found sensitive to the presence of C1q in the serum only at the IgG-coated surface. We suggest that spontaneously adsorbed IgM activates the complement system and interacts with neutrophils by C1q-independent mechanisms.

  • 38.
    Wetterö, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, The Institute of Technology.
    Bengtsson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Complement activation on immunoglobulin G-coated hydrophobic surfaces enhances the release of oxygen radicals from neutrophils through an actin-dependent mechanism2000In: Journal of Biomedical Materials Research, ISSN 0021-9304, E-ISSN 1097-4636, Vol. 51, no 4, p. 742-751Article in journal (Refereed)
    Abstract [en]

    Neutrophil granulocytes are among the first cells to encounter a plasma protein-coated implant and may through frustrated phagocytosis release toxic oxidative species. We used two model surfaces, hydrophobic and hydrophilic glass, to investigate the effects of plasma immunoglobulin G (IgG)-complement interactions for neutrophil adhesion and respiratory burst. The respiratory burst was measured with luminol-amplified chemiluminescence and cell adhesion was determined by labeling neutrophils with 2′, 7′-bis-(carboxy-ethyl)-5(6)-carboxyfluorescein. We demonstrate that the IgG-triggered neutrophil adhesion and oxygen radical production is augmented in the presence of normal human serum, in particular on hydrophobic surfaces, indicating that complement factors enhance the neutrophil activation. We propose that the complement factors C3, C5a, and C1q are especially important for this amplification, but factor B is probably not. Disturbance of the actin filament dynamics with cytochalasin B or jasplakinolide blocked the neutrophil radical generation on all surfaces. However, these drugs did not affect the number of adherent neutrophils. We suggest that there is a synergistic interaction between adsorbed IgG, and the complement system, which amplifies the neutrophil acute inflammatory responses through a dynamic actin cytoskeleton on synthetic surfaces.

  • 39.
    Wetterö, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, The Institute of Technology.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bengtson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Platelets stimulated by IgG-coated surfaces bind and activate neutrophils through a selectin-dependent pathway2003In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 24, no 9, p. 1559-1573Article in journal (Refereed)
    Abstract [en]

    Blood platelets bind rapidly to foreign surfaces and interact with adsorbed proteins and neutrophil granulocytes. We demonstrate by use of luminol-amplified chemiluminescence under stirred and non-stirred conditions that platelets at IgG-coated surfaces amplify the neutrophil extracellular release of reactive oxygen species (ROS). The neutrophil response involved tyrosine phosphorylation, but was only in part induced by neutrophil Fcγ-receptor stimulation. The platelet mediated effects were contact-dependent since the respiratory burst was inhibited when the IgG-stimulated platelets were removed by filtration, but not when they were fixed in paraformaldehyde. Bodipyphallacidin-staining of filamentous actin (F-actin) revealed that an actin-dependent platelet adhesion supported the subsequent adhesion and spreading of neutrophils. The neutrophil ROS-response was lowered when the interaction between platelet P-selectin (CD62P) and neutrophil P-selectin glycoprotein ligand-l (PSGL-1 or CD162) was inhibited. The blocking of L-selectin (CD62L) or blocking of the interaction between platelet glycoprotein (Gp) IIb/IIIa and neutrophil complement receptor 3 (CR3) showed no effect. We conclude that platelet activation on immobilized IgG trigger a contact-dependent “frustrated” phagocytosis by neutrophils, associated with a release of toxic ROS.

  • 40.
    Whiss, Per A
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Larsson, Rutger
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Nephrology. Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL.
    Comparison of plasma levels of cytokines and in vitro generation of reactive oxygen species after nicotine infusion in nicotine users with normal and impaired renal function2003In: Immunopharmacology and immunotoxicology, ISSN 0892-3973, E-ISSN 1532-2513, Vol. 25, no 2, p. 131-144Article in journal (Refereed)
    Abstract [en]

    Several in vitro and animal studies suggest effects of nicotine on the immune system, but little evidence exists regarding the in vivo immunomodulation of nicotine in humans. The increased use of nicotine replacement therapy to aid smoking cessation claims further understanding of how nicotine affects blood leukocytes. This is of particular importance when nicotine therapy is used in diseases associated with alterations of the immune system, such as chronic renal failure. The present study evaluates the acute effects of nicotine infusion (NI) on some immunoregulatory functions in seven healthy subjects and seven patients with renal failure. All subjects were nicotine users and had refrained from using nicotine for 36h before NI. Blood was collected before, immediately after, and 2h after NI. Plasma concentrations of intercellular adhesion molecule-1 (ICAM-1) and the cytokines interleukin-2 (IL-2), IL-4, IL-10, interferon-? and RANTES were measured using specific immunoassays. The generation of reactive oxygen species (ROS) induced by formyl-methionyl-leucyl-phenylalanine (fMLP), Ristocetin, adenosine 5'-diphosphate, or collagen was registered in whole blood as luminol-dependent chemiluminescence. Except for fMLP, these compounds induce leukocyte ROS generation by platelet mediated mechanisms. NI did not significantly affect the levels of the cytokines and ICAM-1 in any group. The peak and the persistent ROS production, induced by collagen and Ristocetin, was lower at some time points in patients with renal failure as compared to healthy subjects. Also in patients with renal failure, both peak height and persistent ROS generation induced by Ristocetin were reduced immediately after NI. Thus, nicotine inhibits some of the platelet-mediated activation of leukocyte ROS generation, and may be associated with platelet defects in renal failure.

  • 41.
    Whiss, Per A
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lundahl, TH
    Bengtsson, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Lindahl, TL
    Lunell, E
    Larsson, R
    Acute effects of nicotine on platelets in healthy and renal impaired nicotine users1998In: XIIIth International Congress of Pharmacology,1998, 1998Conference paper (Other academic)
  • 42.
    Whiss, Per A.
    et al.
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lundahl, Tom H.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Bengtsson, Torbjörn
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lunell, Erik
    Department of Clinical Pharmacology, University Hospital, Lund, Sweden.
    Larsson, Rutger
    Östergötlands Läns Landsting, Centre for Medicine, Department of Nephrology UHL. Linköping University, Faculty of Health Sciences.
    Acute Effects of Nicotine Infusion on Platelets in Nicotine Users with Normal and Impaired Renal Function2000In: Toxicology and Applied Pharmacology, ISSN 0041-008X, E-ISSN 1096-0333, Vol. 163, no 2, p. 95-104Article in journal (Refereed)
    Abstract [en]

    The role of platelets in cardiovascular disease associated with smoking is becoming more established, but the effects of nicotine on platelets are unclear. Nicotine therapy is used for smoking cessation in both health and disease. Consequently, the effects of nicotine on platelets are of particular significance in disorders such as renal disease, which is associated with defective platelet function, increased cardiovascular morbidity, and altered nicotine metabolism. Thus, the aim of the present study was to investigate the acute effects of nicotine infusion (NI) on platelets in seven healthy subjects (HS) and seven patients with renal failure (RF). All subjects were nicotine users and had refrained from using nicotine for 36 h before NI. Blood was collected before, immediately after, and 2 h after NI. The plasma concentrations of nicotine and its main metabolite cotinine were determined by gas chromatography. Platelet responsiveness was assessed by aggregometry and flow cytometry in whole blood (P-selectin surface expression, fibrinogen- and von Willebrand factor-binding), P-selectin expression in isolated platelets, and immunoassays of platelet release (β-thromboglobulin, platelet factor 4, and soluble P-selectin) and nitric oxide (NO) products. The plasma levels of cotinine, but not nicotine, were significantly higher in RF compared to HS at all time points. In both groups, collagen-induced platelet aggregation was restrained immediately after NI, when the plasma concentration of nicotine was maximal, and was restored after 2 h. Two hours after NI, activation-dependent P-selectin surface expression in isolated platelets increased in both groups. This increased platelet responsiveness occurred simultaneously with a significant increase of plasma cotinine and a decrease of NO products. Thus, the present study suggests that nicotine, directly or through some secondary mechanism or metabolite, only slightly potentiates some of the platelet responses. Renal failure appears not to influence the effects of nicotine on platelets.

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