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Gan, Lisha
Publications (10 of 13) Show all publications
Hackett, J. M., Lagali, N., Merrett, K., Edelhauser, H., Sun, Y., Gan, L., . . . Fagerholm, P. (2011). Biosynthetic corneal implants for replacement of pathologic corneal tissue: performance in a controlled rabbit alkali burn model. Investigative Ophthalmology and Visual Science, 52(2), 651-657.
Open this publication in new window or tab >>Biosynthetic corneal implants for replacement of pathologic corneal tissue: performance in a controlled rabbit alkali burn model
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2011 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 52, no 2, 651-657 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To evaluate the performance of structurally reinforced, stabilized recombinant human collagen-phosphorylcholine (RHCIII-MPC) hydrogels as corneal substitutes in a rabbit model of severe corneal damage.

Methods: One eye each of 12 rabbits received a deep corneal alkali wound. Four corneas were implanted with RHCIII-MPC hydrogels. The other eight control corneas were implanted with either allografts or a simple crosslinked RHCIII hydrogel. In all cases, 6.25 mm diameter, 350 µm thick buttons were implanted by anterior lamellar keratoplasty to replace damaged corneal tissue. Implants were followed for nine months by clinical examination and in vivo confocal microscopy, after which implanted corneas were removed and processed for histopathological and ultrastructural examination.

Results: Alkali exposure induced extensive central corneal scarring, ocular surface irregularity, and neovascularization in one case. All implants showed complete epithelial coverage by four weeks post-operative, but with accompanying suture-induced vascularization in 6/12 cases. A stable, stratified epithelium with hemidesmosomal adhesion complexes regenerated over all implants, and subbasal nerve regeneration was observed in allograft and RHCIII-MPC implants. Initially acellular biosynthetic implants were populated with host-derived keratocytes as stromal haze subsided and stromal collagen was remodeled. Notably, RHCIII-MPC implants exhibited resistance to vascular ingrowth while supporting endogenous cell and nerve repopulation.

Conclusion: Biosynthetic implants based on RHC promoted cell and nerve repopulation in alkali burned rabbit eyes. In RHCIII-MPC implants, evidence of an enhanced resistance to neovascularization was additionally noted.

Place, publisher, year, edition, pages
Research in Vision and Opthalmology, 2011
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-65890 (URN)10.1167/iovs.10-5224 (DOI)000287846300002 ()
Note
Original Publication: Joanne M. Hackett, Neil Lagali, Kimberley Merrett, Henry Edelhauser, Yifei Sun, Lisha Gan, May Griffith and Per Fagerholm, Biosynthetic corneal implants for replacement of pathologic corneal tissue: performance in a controlled rabbit alkali burn model, 2011, Investigative Ophthalmology and Visual Science. http://dx.doi.org/10.1167/iovs.10-5224 Copyright: Research in Vision and Opthalmology http://www.arvo.org/Available from: 2011-02-24 Created: 2011-02-24 Last updated: 2017-12-11
Bourghardt Peebo, B., Gan, L., Sun, X.-F., Knutsen Holmqvist, A., Rearden, A. & Fagerholm, P. (2007). Expression of the focal adhesion protein PINCH in normal and alkali-injured corneas and the role of PMNs. Acta Ophthalmologica Scandinavica, 85(4), 395-400.
Open this publication in new window or tab >>Expression of the focal adhesion protein PINCH in normal and alkali-injured corneas and the role of PMNs
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2007 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 85, no 4, 395-400 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To evaluate the role of particularly interesting new cysteine-histidine-rich protein (PINCH) in corneal wound healing and early neovascularization and to assess the influence of granulocytes. Methods: A standardized corneal alkali wound was inflicted under general anaesthesia to the right eye of 14 New Zealand White rabbits. Seven of the rabbits received i.v. 5 mg/kg fucoidin every 2 hours to prevent granulocytes from entering the wound area. After 36 hours, the rabbits were killed, the corneas excised, fixed in 4% formaldehyde and embedded in paraffin. The sections were double-stained with antibodies against PINCH and with haematoxylin. Results: In the normal cornea and limbus, PINCH was weakly expressed in the corneal epithelium and in a wedge of the conjunctival stroma. In the wounded corneas, PINCH expression was seen in the frontline of repopulating endothelial and epithelial cells, and in active keratocytes. The vascular endothelium and the granulocytes expressed PINCH, as did the conjunctival epithelium. In the fucoidin-treated rabbits, PINCH expression was markedly reduced. The vascular endothelial cells and the few granulocytes did not express PINCH in these rabbits. Conclusions: PINCH is only slightly expressed in the normal cornea. A corneal wound induces PINCH expression in the repopulating cells, in the vascular endothelial cells of the limbus, in the limbal epithelium and in the granulocytes. Exclusion of granulocytes reduces expression of PINCH and there is no expression at all in the vascular endothelium. © 2007 The Authors Journal compilation 2007 Acta Ophthalmol Scand.

Keyword
cornea - rabbit - wound healing - PINCH - neovascularization
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-39238 (URN)10.1111/j.1600-0420.2006.00861.x (DOI)47594 (Local ID)47594 (Archive number)47594 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Panagiotopoulos, M., Gan, L. & Fagerholm, P. (2007). Stroma remodelling during healing of corneal surface irregularities induced by PTK. Acta Ophthalmologica Scandinavica, 85(4), 387-394.
Open this publication in new window or tab >>Stroma remodelling during healing of corneal surface irregularities induced by PTK
2007 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 85, no 4, 387-394 p.Article in journal (Refereed) Published
Abstract [en]

Purpose:  To study the histopathology of the remodelling process in the stroma after excimer-laser-induced corneal irregular injuries.

Methods:  Seven New Zealand white rabbits received in one eye a transepithelial plano photoablation (60 µm) and an additional plano ablation (25 µm). On the denuded stroma, an electron microscopy specimen grid was placed and another 25 µm ablation was applied to produce surface irregularities. Dichlorotriazinyl aminofluorescein (DTAF) was then applied for 45 seconds. Another seven right eyes of seven rabbits were ablated the same way but without using the grid, resulting in a plano ablation. All the rabbits were killed at weekly intervals after treatment. The harvested corneas from both eyes were further processed for haematoxylin-eosin staining and were also stained with monoclonal antibodies directed against Ki-67 antigen and α-smooth muscle actin (α-SMA). All specimens were examined under light and fluorescence microscope.

Results:  The corneal wounds were covered by epithelium during the first week. The 25 µm × 25 µm × 25 µm stromal irregularities were clearly discernible up to 3 weeks after treatment, during which time they melted and disappeared. A homogeneous zone was formed in which stroma cells laid down an initially disorganized stroma. This was sharply visible under a fluorescence microscope as a dark area between the dichlorotriazinyl aminofluorescein (DTAF) fluorescent stroma and autofluorescent epithelium. Very little response was seen in the plano-ablated wound microscopically and in terms of positive stained cells.

Conclusion:  As the irregularities are flattened and the homogenous zone becomes repopulated with keratocytes forming extracellular matrix material (ECM), the cornea regains its previous architecture in both groups. The irregular wound surface promotes wound-healing reactivity, a process that allows the cornea to compensate for the irregularities and heal to a functional state.

Keyword
DTAF - excimer laser keratectomy - rabbit cornea - surface irregularities - wound healing
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-39242 (URN)10.1111/j.1600-0420.2006.00852.x (DOI)47599 (Local ID)47599 (Archive number)47599 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13Bibliographically approved
Liu, Y., Gan, L., Carlsson, D. J., Fagerholm, P., Lagali, N., Watsky, M. A., . . . Griffith, M. (2006). A simple, cross-linked collagen tissue substitute for corneal implantation. Investigative Ophthalmology and Visual Science, 47(5), 1869-1875.
Open this publication in new window or tab >>A simple, cross-linked collagen tissue substitute for corneal implantation
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2006 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 47, no 5, 1869-1875 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE. To develop a simple corneal substitute from crosslinked collagen. METHODS. Porcine type I collagen (10%, pH 5), was mixed with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The final homogenous solution was molded to corneal dimensions, cured, and then implanted into rabbits and minipigs by lamellar keratoplasty. The implants were followed for up to 6 months after surgery. Clinical examinations of the cornea included detailed slit lamp biomicroscopy, in vivo confocal microscopy, topography and esthesiometry for nerve function. Histopathologic examinations were also performed on rabbit corneas harvested after 6 months. RESULTS. Cross-linked collagen (refractive index, 1.35) had optical clarity superior to human corneas. Implanted into rabbit and porcine corneas, only 1 of 24 of the surgical corneas showed a slight haze at 6 months after surgery. All other implants showed no adverse reactions and remained optically clear. Topography showed a smooth surface and a profile similar to that of the contralateral nonsurgical eye. The implanted matrices promoted regeneration of corneal cells, tear film, and nerves. Touch sensitivity was restored, indicating some restoration of function. The corneas with implants showed no significant loss of thickness and demonstrated stable host- graft integration. CONCLUSIONS. Collagen can be adequately stabilized, using water soluble carbodiimides as protein cross-linking reagents, in the fabrication of corneal matrix substitutes for implantation. The simple cross-linking methodology would allow for easy fabrication of matrices for transplantation in centers where there is a shortage of corneas, or where there is need for temporary patches to repair perforations in emergency situations. Copyright © Association for Research in Vision and Ophthalmology.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-36070 (URN)10.1167/iovs.05-1339 (DOI)29725 (Local ID)29725 (Archive number)29725 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Gan, L., Fagerholm, P. & Palmblad, J. (2005). Expression of basic fibroblast growth factor in rabbit corneal alkali wounds in the presence and absence of granulocytes. Acta Ophthalmologica Scandinavica, 83(3), 374-378.
Open this publication in new window or tab >>Expression of basic fibroblast growth factor in rabbit corneal alkali wounds in the presence and absence of granulocytes
2005 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 83, no 3, 374-378 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To study the expression of basic fibroblast growth factor (bFGF) in the early phases of corneal wound healing in the presence or absence of granulocytes. Methods: A central penetrating corneal alkali wound was inflicted to one eye in each of 14 rabbits under general anaesthesia. Subsequently, seven of the rabbits were given fucoidin i.v. for 36 hours in order to block the selectins on the vascular endothelium, thus preventing blood granulocytes from entering the tissues. Then, corneas were prepared, stained for bFGF and evaluated by light microscopy. Results: Whereas normal corneal epithelium expressed bFGF weakly, conjunctival epithelium did so strongly, particularly the goblet cells. The corneal endothelium showed medium staining, while keratocytes and vascular endothelial cells did not consistently express bFGF. After 36 hours of wound healing, a marked upregulation of bFGF expression was observed in the corneal epithelial and endothelial cells, as well as in the keratocytes, that were migrating into the wound. No other changes were noted. None of these features were modulated when granulocyte emigration was prevented by fucoidin administration. Conclusions: The difference in bFGF expression between the corneal and conjunctival epithelium suggests a role for this growth factor in the barrier function at the limbus. Moreover, the specific presence of bFGF in cells migrating into the wound indicates the participation of bFGF in corneal wound healing. Expression of bFGF was independent of granulocytes. Copyright © Acta Ophthalmol Scand 2005.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-30123 (URN)10.1111/j.1600-0420.2005.00439.x (DOI)15602 (Local ID)15602 (Archive number)15602 (OAI)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13
Fagerholm, P., Gan, L. & Palmblad, J. (2004). Vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 in the regulation of corneal neovascularization and wound healing. Acta Ophthalmologica Scandinavica, 82(5), 557-563.
Open this publication in new window or tab >>Vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 in the regulation of corneal neovascularization and wound healing
2004 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 82, no 5, 557-563 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To study the change in expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 in the rabbit cornea and limbus following a penetrating, central corneal alkali burn. The influence of different cells on VEGF and VEGFR-2 expression was studied by excluding granulocytes from the wound area. Methods: Fourteen New Zealand white rabbits were subjected to a penetrating, 5-mm diameter, central corneal alkali burn in one eye under general anaesthesia. Seven of the rabbits were given injections of fucoidin for 36 hours. The rabbits were killed after 36 hours and the corneas were excised with a sclera rim and prepared for immunohistochemistry. Results: Both VEGF and VEGFR-2 are strongly expressed in the frontline of repopulating epithetial, stromal and endothelial cells during wound healing, irrespective of granulocyte presence. Vascular endothelial cells express VEGF strongly after injury, but only in the presence of granulocytes. Conclusion: Corneal neovascularization requires the presence of granulocytes to stimulate vascular endothelial cells. During wound healing in this area, VEGF is a factor that stimulates proliferation and migration and that is not influenced by granulocytes.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24719 (URN)10.1111/j.1600-0420.2004.00312.x (DOI)6968 (Local ID)6968 (Archive number)6968 (OAI)
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
Gan, L., Hakim, M., Mintsioulis, G. & Griffith, M. (2003). Human corneal cellular response to the synthetic stromal matrix replacements. Investigative Ophthalmology and Visual Science, 44.
Open this publication in new window or tab >>Human corneal cellular response to the synthetic stromal matrix replacements
2003 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 44, 4693- p.Conference paper, Published paper (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-48481 (URN)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Gan, L., Fagerholm, P., Blalock, T. & Schultz, G. (2002). Connective tissue growth factor (CTGF) in the alkali wounded corneas. Investigative Ophthalmology and Visual Science, 43.
Open this publication in new window or tab >>Connective tissue growth factor (CTGF) in the alkali wounded corneas
2002 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 43, 4207- p.Conference paper, Published paper (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-48479 (URN)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Fagerholm, P., Gan, L. & Palmblad, J. (2002). Expression of VEGF and its receptor VEGFR-2/flk-1 following rabbit corneal alkali burn in the presence and absence of granulocytes. Investigative Ophthalmology and Visual Science, 43.
Open this publication in new window or tab >>Expression of VEGF and its receptor VEGFR-2/flk-1 following rabbit corneal alkali burn in the presence and absence of granulocytes
2002 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 43, 4210- p.Conference paper, Published paper (Other academic)
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-48480 (URN)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-12
Gan, L., Hamberg-Nyström, H., Fagerholm, P. & Van Setten, G. (2001). Cellular proliferation and leukocyte infiltration in the rabbit cornea after photorefractive keratectomy. Acta Ophthalmologica Scandinavica, 79(5), 488-492.
Open this publication in new window or tab >>Cellular proliferation and leukocyte infiltration in the rabbit cornea after photorefractive keratectomy
2001 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 79, no 5, 488-492 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To map the proliferative activity of corneal cells during wound healing following photorefractive keratectomy (PRK) and to compare two markers for proliferation. Methods: PRK, 5- mm in diameter with a -6 D setting, was performed in one eye of 28 New Zealand White Rabbits. The rabbits were sacrificed at time points between 12 hours and three months after surgery. The treated and fellow corneas were fixed in 10% formaldehyde, paraffin embedded, and immunohistochemically stained for proliferate cell nuclear antigen (PCNA) and at one time point, 1 week, also for Ki-67. Results: Following initial sliding of the epithelial cells, the proliferative activity in the wound area starts in the leading edge (24 hours) and is spread towards the periphery. The proliferative activity peaks after one week and subsides during the following two weeks. Early (24 hours) proliferative activity is also seen in the limbal epithelium which peaks after three days. The keratocytes express PCNA in the peripheral stroma 48 hours after injury. They then also migrate to repopulate the stroma under the wound area. The expression period lasts 1 week and subsides the following week. Leukocytes are found in the wound as early as 12 hours after injury. The cells disappear around the time of epithelial wound closure, i.e. after 3 days. The two proliferative markers PCNA and KI 67 show a similar distribution after surgery. Conclusion: Epithelial proliferative activity starts earlier after injury, and is preceded by leukocyte presence in the wound. The PCNA expression starts later in the keratocytes but lasts somewhat longer (3 weeks). PCNA expression appears more efficient than Ki-67 to show proliferative activity of slow cycling cells in the cornea.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27741 (URN)10.1034/j.1600-0420.2001.790512.x (DOI)12482 (Local ID)12482 (Archive number)12482 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13
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