Aims/Hypothesis: Islet amyloid polypeptide (IAPP) is a beta cell hormone secreted together with insulin upon glucose stimulation. IAPP participates in normal glucose regulation, but IAPP is also known for its ability to misfold and form islet amyloid. Amyloid fibrils form through smaller cell toxic intermediates and deposited amyloid disrupts normal islet architecture. Even though IAPP and amyloid formation are much discussed in type 2 diabetes, our aim was to study the significance of IAPP in type 1 diabetes. Results: Plasma IAPP levels in children and adolescents with newly diagnosed type 1 diabetes (n = 224) were analysed and concentrations exceeding 100 pmol/L (127.2 - 888.7 pmol/L) were found in 11% (25/224). The IAPP increase did not correlate with C-peptide levels. Conclusions/Interpretation: Plasma levels of IAPP and insulin deviate in a subpopulation of young with newly-diagnosed type 1 diabetes. The determined elevated levels of IAPP might increase the risk for IAPP misfolding and formation of cell toxic amyloid in beta cells. This finding add IAPP-aggregation to the list over putative pathological factors causing type 1 diabetes.

Strategies are important in today’s highly competitive environments. Businesses as well as public-sector organisations need a unifying logic, which emerges out of dialogues among its members and guides their actions. The organization’s Control System has potential to become a key to this, and itself a source of competitiveness.

Controlling for Competitiveness describes how management control is crucial in mobilizing, using and communicating the knowledge and skills of managers and employees. Controllers should design situation-specific control systems, assuring that actions will be based on appropriate information and incentives. Enterprise Systems facilitate coordination and information exchange, thus enabling the development of a consistent and congruent strategy throughout the organization. The involvement of all levels of management as well as most employees in this process creates motivation and commitment to the organization’s strategy. It also prepares for executing strategy through a creative use of metrics, decision tools and clarified responsibilities.

The authors underline the need to understand management control as part of the  organisation’s control mix (control package). They provide numerous examples of how systems and people interact in shaping a strategic focus in private as well as publicly owned organizations.

In addition to the authors’ experiences from research and consultancy, the book is based on recent interviews with 16 leading, complex organizations in the private and public sector.  Numerous examples from these and other organizations are provided.

Our aim was to study, at the same glycemic control, how treatment with either the insulin secretagogue repaglinide or exogenous insulin aspart affects endogenous insulin secretion, plasma insulin and IAPP (islet amyloid polypeptide) levels, GH-IGF (growth hormone-insulin-like growth factor) axis and plasma lipoprotein concentrations in patients with type 2 diabetes. Five patients, age 65.0 +/- A 4.1 years (mean +/- A SE), body weight 82.5 +/- A 5.0 kg, BMI (body mass index) 27.7 +/- A 1.5 kg/m(2) were treated for 10 weeks with repaglinide or insulin aspart in a randomized, cross-over study. At the end of each treatment a 24-h metabolic profile was performed. Blood glucose, C-peptide, free human insulin, free total (human and analogue) insulin, proinsulin, IAPP, IGF-I, IGFBP-1 (IGF binding protein-1), GHBP (growth hormone binding protein) and plasma lipoprotein concentrations were measured. Similar 24-h blood glucose profiles were obtained with repaglinide and insulin aspart treatment. During the repaglinide treatment, the meal related peaks of C-peptide and free human insulin were about twofold higher than during treatment with insulin aspart. Proinsulin, GHBP were higher and IAPP levels tended to be higher during repaglinide compared to insulin aspart. Postprandial plasma total cholesterol, triglycerides and apolipoprotein B concentrations were higher on repaglinide than on insulin aspart treatment. Our results show that, at the same glycemic control, treatment with exogenous insulin aspart in comparison with the insulin secretagogue repaglinide result in a lower endogenous insulin secretion, and a tendency towards a less atherogenic postprandial lipid profile.

Following the encouraging report of the Edmonton group, there was a rejuvenation of the islet transplantation field. After that, more pessimistic views spread when long-term results of the clinical outcome were published. A progressive loss of the beta-cell function meant that almost all patients were back on insulin therapy after 5 years. More than 10 years ago, we demonstrated that amyloid deposits rapidly formed in human islets and in mouse islets transgenic for human IAPP when grafted into nude mice. It is, therefore, conceivable to consider amyloid formation as one potential candidate for the long-term failure. The present paper reviews attempts in our laboratories to elucidate the dynamics of and mechanisms behind the formation of amyloid in transplanted islets with special emphasis on the impact of long-term hyperglycemia.

Amyloid formation is cytotoxic and can activate the caspase cascade. Here, we monitor caspase-3-like activity as reduction of fluorescence resonance energy transfer (FRET) using the contstruct pFRET2-DEVD containing enhanced cyan fluorescent protin (EYFP) linked by the caspase-3 specific cleavage site residues DEVD. Beta-TC-6 cells were transfected, and the fluoorescence was measured at 440 nm excitation and 535 nm (EYFP) and 480 nm (ECFP) emission wavelength. Cells were incubated with recombinant pro lset Amyloid Polypeptide (rec prolAPP) or the processing metabolites of prolAPP; the N-terminal flanking peptide withIAPP (recN+IAPP); IAPP with the C-terminal flanking peptied (recIAPP+C) and lslet Amyloid Polypeptide (recIAPP). Peptides were added in solubilized from (50 mu M) or as performed amyloid-like fibrils, or as a combination of these. FRET was measured and incubation with a mixture of solubilized peptide and performed fibrils resulted in loss of FRET and apoptosis was determined to occurein cells incubated with recproIAPP (49%), recN+IAPP (46%), recIAPP (72%) and recIAPP+C (59%). These results show that proIAPP and the processing intermediates reside the same cell toxic capacity as IAPP, and they can all have a central role in the reduction of beta-cell number in type 2 diabetes.

Islet amyloid polypeptide (IAPP) can aggregate into amyloid, a common pathological finding present extracellularly in the islets of Langerhans in individuals with type 2 diabetes. IAPP arises from posttranslational processing of the precursor proIAPP. Accumulation of proIAPP in the secretory granules can result in proIAPP-amyloid formation. We raise the following hypothesis; proIAPP can under not yet defined circumstances aggregate into amyloid-like fibrils intracellularly and at this location act as template and cross-seed amyloid formation of IAPP. We have produced recombinant peptides corresponding to proIAPP and IAPP. These peptides aggregate readily into fibrils with typical amyloid characteristics. Sonicated recproIAPP- and recIAPP- preformed fibrillar aggregates were injected intravenously to +/hIAPP/-mIAPP transgenic mice. Male mice from this strain develop islet amyloid in response to high fat diet. Control animals received an injection of preformed amyloid fibrils from the proinsulin processing intermediate (C-peptide/A-chain) or sodium chloride. All animals were fed a diet high in fat over a ten month period. The presence of islet amyloid was studied after Congo red staining. We found amyloid in 20 % of the islets in animals injected with preformed recIAPP fibrils and in 10 % of the islets in animals injected with preformed recproIAPP fibrils. Control animals developed amyloid in 1-2% of the islets. Our results support the hypothesis that proIAPP-fibrils can act as template and induce conformational changes in soluble IAPP that results in propagation of the amyloid fibrils. This is the first report on in vivo seeding of a localized amyloid form and we present data that support transport of amyloid between islets as a putative route for the spreading of islet amyloid. Our finding suggests that therapies, which use capping of fibril endings, might be useless.

AIMS/HYPOTHESIS: The amount of visceral fat mass strongly relates to insulin resistance in humans. The transcription factor peroxisome proliferator activated receptor gamma (PPARG) is abundant in adipocytes and regulates genes of importance for insulin sensitivity. Our objective was to study PPARG activity in human visceral and subcutaneous adipocytes and to compare this with the most common model for human disease, the mouse.

MATERIALS AND METHODS: We transfected primary human adipocytes with a plasmid encoding firefly luciferase controlled by PPARG response element (PPRE) from the acyl-CoA-oxidase gene and measured PPRE activity by emission of light. RESULTS: We found that PPRE activity was 6.6-fold higher (median) in adipocytes from subcutaneous than from omental fat from the same subjects (n = 23). The activity was also 6.2-fold higher in subcutaneous than in intra-abdominal fat cells when we used a PPARG ligand-binding domain-GAL4 fusion protein as reporter, demonstrating that the difference in PPRE activity was due to different levels of activity of the PPARG receptor in the two fat depots. Stimulation with 5 micromol/l rosiglitazone did not induce a PPRE activity in visceral adipocytes that was as high as basal levels in subcutaneous adipocytes. Interestingly, in mice of two different strains the PPRE activity was similar in visceral and subcutaneous fat cells.

CONCLUSIONS/INTERPRETATION: We found considerably lower PPARG activity in visceral than in subcutaneous primary human adipocytes. Further studies of the molecular mechanisms behind this difference could lead to development of drugs that target the adverse effects of visceral obesity.

Aims/hypothesis: Islet amyloid is a frequent finding in the islets of Langerhans of individuals with type 2 diabetes. The main amyloid constituent is the beta cell-derived polypeptide hormone islet amyloid polypeptide (IAPP). In general, amyloid refers to an extracellular deposit of a congophilic material, but intracellular amyloid is seen in some beta cells of transgenic mice expressing the gene for human IAPP and in human islets transplanted into nude mice. The aim of this study was to immunohistochemically characterise the intracellular amyloid. Methods: Antisera against the N- and C-terminal processing sites of proIAPP (which were therefore specific for proIAPP), the C-terminal flanking peptide and mature IAPP were used for immunoelectron microscopy. Results: Fibrillar aggregates were seen in the halo region of the secretory granules in some beta cells in human IAPP transgenic mice. These aggregates were labelled with proIAPP-specific antisera. Also, proIAPP reactivity was more widespread in the intracellular amyloid-like aggregates in beta cells of transgenic mice than in human islet transplants, in which the intracellular amyloid-like deposits were larger, but the proIAPP labelling was restricted to small spots within the amyloid deposits. Conclusions/ interpretation: We suggest that proIAPP forms the first amyloid fibrils and that this can occur already in the secretory granules of the beta cells. The proIAPP-derived fibrils can act as seed for further amyloid formation, now made up by IAPP. The observed difference between human islet transplants and human IAPP transgenic animals may reflect differences in stages of amyloid development. © Springer-Verlag 2006.

Amyloid is defined as extracellular protein aggregates with a characteristic fibrillar ultra-structure, Congo red affinity and a unique x-ray diffraction pattern. At present, 25 different human amyloid fibril proteins have been identified, and amyloid aggregation is associated with pathological manifestations such as Alzheimer’s disease, spongiform encephalopathy and type 2 diabetes. Amyloid aggregation triggers apoptosis by incorporation of early oligomers in cellular membranes, causing influx of ions. Amyloid is the only visible pathological islet alteration in subjects with type 2 diabetes, and islet amyloid polypeptide (IAPP) is the major islet amyloid fibril component. IAPP is produced by beta-cells and co-localized with insulin in the secretory granules. Both peptides are synthesised as pro-molecules and undergo proteolytic cleavage by the prohormone convertase 1/3 and 2. Although IAPP is the main amyloid constituent, both proIAPP and proIAPP processing intermediates have been identified in islet amyloid.

The aim of this thesis was to study the role of impaired processing of human proIAPP in early islet amyloidogenesis. Five cell lines with individual processing properties were transfected with human proIAPP and expression, aggregation and viability were studied. Cells unable to process proIAPP into IAPP or to process proIAPP at the N-terminal processing site accumulated intracellular amyloid-like aggregates and underwent apoptosis. Further, proIAPP immunoreactivity was detected in intracellular amyloid-like aggregates in betacells from transgenic mice expressing human IAPP and in transplanted human beta-cells. ProIAPP was hypothesized to act as a nidus for further islet amyloid deposition, and to investigate this theory, amyloid-like fibrils produced from recombinant IAPP, proIAPP and insulin C-peptide/A-chain were injected in the tail vein of transgenic mice expressing the gene for human IAPP. Pancreata were recovered after 10 months and analysed for the presence of amyloid. Both IAPP and proIAPP fibrils but not des-31,32 proinsulin fibrils, caused an increase in affected islets and also an increase of the amyloid amount. This finding demonstrates a seeding capacity of proIAPP on IAPP fibrillogenesis. IAPP has been known for some time to trigger apoptosis in cultured cells, and a novel method for real time detection of apoptosis in beta-cells was developed. Aggregation of recombinant proIAPP and proIAPP processing intermediates were concluded to be inducers of apoptosis as potent as IAPP fibril formation.

From the results of this study, a scenario for initial islet amyloidogenesis is proposed. Initial amyloid formation occurs intracellularly as a result of alterations in beta-cell processing capacity. When the host cell undergoes apoptosis intracellular proIAPP amyloid becomes extracellular and can act as seed for further islet amyloid deposition.

The amyloid present in the islets of Langerhans in type 2 diabetes is polymerized islet amyloid polypeptide (IAPP). The precursor protein proIAPP is posttranslationally modified, a process involving the removal of NH2- and COOH-terminal flanking peptides. This step is performed by the prohormone convertases PC2 and PC1/3. PC2 processes proIAPP preferably at the NH 2-terminal processing site, and PC1/3 processes proIAPP exclusively at the COOH-terminal site. Little is known regarding the exact circumstances leading to islet amyloid formation. In this study, we have examined the possible significance of aberrant processing of proIAPP on amyloid formation in several in vitro cellular systems. In our studies, human (h)-proIAPP was transfected into β-TC-6 cells expressing both prohormone convertases and in which proIAPP is processed into IAPP. Additionally, h-proIAPP was transfected into three different pituitary-derived cell lines with different prohormone convertase profiles: AtT-20 cells (deficient in PC2), GH3 cells (deficient in PC1/3), and GH4C1 cells (deficient in both convertases). We followed the processing of h-proIAPP with antibodies specific for the respective cleavage sites and stained the cells with Congo red to verify the accumulation of amyloid. Incomplete processing of h-proIAPP that occurs in AtT-20 and GH4C1 cells resulted in the formation of intracellular amyloid. No amyloid developed in β-TC-6 and GH3 cells lines with full processing of proIAPP. An intracellular increase in proIAPP and/or its metabolic products may thus promote intracellular amyloid formation, thereby causing cell death. When extracellularly exposed, this amyloid might act as template for continuing amyloid formation from processed IAPP released from the surrounding β-cells. © 2005 by the American Diabetes Association.