The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform

Virender S. Sangwan - One of the best experts on this subject based on the ideXlab platform.

  • Optimizing the role of Limbal explant size and source in determining the outcomes of Limbal Transplantation: An in vitro study.
    PLOS ONE, 2017
    Co-Authors: Abhinav Reddy Kethiri, Virender S. Sangwan, Sayan Basu, Sachin Shukla, Vivek Singh
    Abstract:

    Purpose Simple Limbal epithelial Transplantation (SLET) and cultivated Limbal epithelial Transplantation (CLET) are proven clinical techniques for treating Limbal stem cell deficiency (LSCD). However, the ideal size and number of the Limbal explants required for Transplantation has not been clearly elucidated. This in vitro study aimed to determine the optimal Limbal explant size required for complete corneal epithelialization by characterizing the cell expansion. Methods Limbal explants obtained from both live and cadaveric biopsies were cultured on the denuded amniotic membrane. Explant size and the explant cell outgrowth (expansion) were measured using ImageJ software with respect to days. Cultures were characterized by assessing the rate of proliferation of cells with 5-bromo-2’-deoxyuridine (BrdU) assay along with the expression of different stem cell markers (ABCG2, p63α), corneal epithelial (CK3+12) and adherens junction molecules (E-Cadherin) by immunofluorescence. Results Explants from live biopsies had 80% growth potential in vitro whereas 40% of the cadaveric tissue failed to grow. Minimum explant sizes of 0.3 mm2 for live and ≥0.5 mm2 for cadaveric tissue had a mean expansion areas of 182.39±17.06 mm2 and 217.59±16.91 mm2 respectively suggesting adequate growth potential of the explants. Mean total percentage of proliferative cells was 31.80±3.81 in live and 33.49±4.25 in cadaveric tissue expansion. The expression was noted to be similar in cells cultured from cadaveric compared to cells cultured from live Limbal tissue with respect to ABCG2, p63α, CK(3+12) and E-cadherin. Conclusion Our findings show that a minimal amount of 0.3 mm2 live tissue would be sufficient for ample Limbal cell expansion in vitro. Cadaveric explants

  • optimizing the role of Limbal explant size and source in determining the outcomes of Limbal Transplantation an in vitro study
    PLOS ONE, 2017
    Co-Authors: Virender S. Sangwan, Sayan Basu, Abhinav Reddy Kethiri, Sachin Shukla, Vivek Singh
    Abstract:

    Purpose Simple Limbal epithelial Transplantation (SLET) and cultivated Limbal epithelial Transplantation (CLET) are proven clinical techniques for treating Limbal stem cell deficiency (LSCD). However, the ideal size and number of the Limbal explants required for Transplantation has not been clearly elucidated. This in vitro study aimed to determine the optimal Limbal explant size required for complete corneal epithelialization by characterizing the cell expansion. Methods Limbal explants obtained from both live and cadaveric biopsies were cultured on the denuded amniotic membrane. Explant size and the explant cell outgrowth (expansion) were measured using ImageJ software with respect to days. Cultures were characterized by assessing the rate of proliferation of cells with 5-bromo-2’-deoxyuridine (BrdU) assay along with the expression of different stem cell markers (ABCG2, p63α), corneal epithelial (CK3+12) and adherens junction molecules (E-Cadherin) by immunofluorescence. Results Explants from live biopsies had 80% growth potential in vitro whereas 40% of the cadaveric tissue failed to grow. Minimum explant sizes of 0.3 mm2 for live and ≥0.5 mm2 for cadaveric tissue had a mean expansion areas of 182.39±17.06 mm2 and 217.59±16.91 mm2 respectively suggesting adequate growth potential of the explants. Mean total percentage of proliferative cells was 31.80±3.81 in live and 33.49±4.25 in cadaveric tissue expansion. The expression was noted to be similar in cells cultured from cadaveric compared to cells cultured from live Limbal tissue with respect to ABCG2, p63α, CK(3+12) and E-cadherin. Conclusion Our findings show that a minimal amount of 0.3 mm2 live tissue would be sufficient for ample Limbal cell expansion in vitro. Cadaveric explants <0.5 mm2 had poor growth potential. However, larger explants (≥ 0.5 mm2) had growth rate and proliferative potential similar to the live tissue. These findings could prove to be critical for clinical success especially while attempting cadaveric Limbal Transplantation. This study provides a novel clinical strategy for enhancing efficacy of the Limbal Transplantation surgery and opens the probability of even using the cadaveric tissue by considering the size of explant.

  • successful autologous simple Limbal epithelial Transplantation slet in previously failed paediatric Limbal Transplantation for ocular surface burns
    Case Reports, 2013
    Co-Authors: Swapnil Bhalekar, Sayan Basu, Virender S. Sangwan
    Abstract:

    A 3-year-old child sustained severe ocular surface burns in her left eye after accidental lime injury. Despite appropriate management in the acute stage, she developed Limbal stem cell deficiency (LSCD) in that eye. This was initially treated with autologous ex vivo cultivated Limbal epithelial Transplantation (CLET), which unfortunately failed after 6 months resulting in recurrence of LSCD. One year following CLET, she underwent simple Limbal epithelial Transplantation (SLET) using autologous donor tissue from the healthy fellow eye. Successful restoration of the ocular surface following SLET combined with amblyopia therapy led to significant cosmetic and functional improvement. One year following SLET her vision in the left eye was 20/80 and she continues to maintain a stable, avascular and completely epithelised corneal surface. This case illustrates that SLET is effective in treating LSCD even in cases that are conventionally considered to be at high risk for failure of Limbal stem cell Transplantation.

  • successful management of immunological rejection following allogeneic simple Limbal epithelial Transplantation slet for bilateral ocular burns
    Case Reports, 2013
    Co-Authors: Swapnil Bhalekar, Sayan Basu, Virender S. Sangwan
    Abstract:

    A 41-year-old woman presented with bilateral total Limbal stem cell deficiency, one year after chemical injury. She underwent allogeneic simple Limbal epithelial Transplantation (SLET) from a cadaveric donor in her right eye. One month later her unaided visual acuity (VA) improved to 20/100 from hand-motions. The corneal surface was avascular and epithelialised. Three months later, she presented with acute pain in right eye with peripheral corneal neovascularisation encircling the transplants, engorged and tortuous periLimbal vessels and diffuse epithelial haze. For a diagnosis of allograft rejection, pulse doses of intravenous methyl prednisolone with intensive topical steroids were administered. Her symptoms resolved in a week, confirming the diagnosis. She recovered her pre-rejection VA. She was maintained on systemic immunosuppressive agents. Her ocular surface continues to be stable. This case describes hitherto unknown clinical features of allograft rejection following SLET and emphasises the importance of continued immunosuppression in allogeneic Limbal Transplantation.

  • Simple Limbal epithelial Transplantation (SLET): a novel surgical technique for the treatment of unilateral Limbal stem cell deficiency
    British Journal of Ophthalmology, 2012
    Co-Authors: Virender S. Sangwan, Sayan Basu, Sheila Macneil, Dorairajan Balasubramanian
    Abstract:

    This study describes a novel surgical technique of Limbal Transplantation, which combines the benefits of existing techniques while avoiding their difficulties. Six patients with unilateral and total Limbal stem cell deficiency following ocular surface burns underwent a single-stage procedure. A 2×2 mm strip of donor Limbal tissue was obtained from the healthy eye and divided into eight to ten small pieces. After surgical preparation of the recipient ocular surface, these tiny Limbal transplants were distributed evenly over an amniotic membrane placed on the cornea. After surgery, a completely epithelialised, avascular and stable corneal surface was seen in all recipient eyes by 6 weeks, and this was maintained at a mean±SD follow-up of 9.2±1.9 months. Visual acuity improved from worse than 20/200 in all recipient eyes before surgery to 20/60 or better in four (66.6%) eyes, while none of the donor eyes developed any complications. This technique requires less donor tissue than previously used for conventional autografting and does not need a specialist laboratory for cell expansion. Although long-term results are awaited, this simple Limbal epithelial Transplantation promises to be an easy and effective technique for treating unilateral Limbal stem cell deficiency following ocular burns.

Sayan Basu - One of the best experts on this subject based on the ideXlab platform.

  • optimizing the role of Limbal explant size and source in determining the outcomes of Limbal Transplantation an in vitro study
    PLOS ONE, 2017
    Co-Authors: Virender S. Sangwan, Sayan Basu, Abhinav Reddy Kethiri, Sachin Shukla, Vivek Singh
    Abstract:

    Purpose Simple Limbal epithelial Transplantation (SLET) and cultivated Limbal epithelial Transplantation (CLET) are proven clinical techniques for treating Limbal stem cell deficiency (LSCD). However, the ideal size and number of the Limbal explants required for Transplantation has not been clearly elucidated. This in vitro study aimed to determine the optimal Limbal explant size required for complete corneal epithelialization by characterizing the cell expansion. Methods Limbal explants obtained from both live and cadaveric biopsies were cultured on the denuded amniotic membrane. Explant size and the explant cell outgrowth (expansion) were measured using ImageJ software with respect to days. Cultures were characterized by assessing the rate of proliferation of cells with 5-bromo-2’-deoxyuridine (BrdU) assay along with the expression of different stem cell markers (ABCG2, p63α), corneal epithelial (CK3+12) and adherens junction molecules (E-Cadherin) by immunofluorescence. Results Explants from live biopsies had 80% growth potential in vitro whereas 40% of the cadaveric tissue failed to grow. Minimum explant sizes of 0.3 mm2 for live and ≥0.5 mm2 for cadaveric tissue had a mean expansion areas of 182.39±17.06 mm2 and 217.59±16.91 mm2 respectively suggesting adequate growth potential of the explants. Mean total percentage of proliferative cells was 31.80±3.81 in live and 33.49±4.25 in cadaveric tissue expansion. The expression was noted to be similar in cells cultured from cadaveric compared to cells cultured from live Limbal tissue with respect to ABCG2, p63α, CK(3+12) and E-cadherin. Conclusion Our findings show that a minimal amount of 0.3 mm2 live tissue would be sufficient for ample Limbal cell expansion in vitro. Cadaveric explants <0.5 mm2 had poor growth potential. However, larger explants (≥ 0.5 mm2) had growth rate and proliferative potential similar to the live tissue. These findings could prove to be critical for clinical success especially while attempting cadaveric Limbal Transplantation. This study provides a novel clinical strategy for enhancing efficacy of the Limbal Transplantation surgery and opens the probability of even using the cadaveric tissue by considering the size of explant.

  • Optimizing the role of Limbal explant size and source in determining the outcomes of Limbal Transplantation: An in vitro study.
    PLOS ONE, 2017
    Co-Authors: Abhinav Reddy Kethiri, Virender S. Sangwan, Sayan Basu, Sachin Shukla, Vivek Singh
    Abstract:

    Purpose Simple Limbal epithelial Transplantation (SLET) and cultivated Limbal epithelial Transplantation (CLET) are proven clinical techniques for treating Limbal stem cell deficiency (LSCD). However, the ideal size and number of the Limbal explants required for Transplantation has not been clearly elucidated. This in vitro study aimed to determine the optimal Limbal explant size required for complete corneal epithelialization by characterizing the cell expansion. Methods Limbal explants obtained from both live and cadaveric biopsies were cultured on the denuded amniotic membrane. Explant size and the explant cell outgrowth (expansion) were measured using ImageJ software with respect to days. Cultures were characterized by assessing the rate of proliferation of cells with 5-bromo-2’-deoxyuridine (BrdU) assay along with the expression of different stem cell markers (ABCG2, p63α), corneal epithelial (CK3+12) and adherens junction molecules (E-Cadherin) by immunofluorescence. Results Explants from live biopsies had 80% growth potential in vitro whereas 40% of the cadaveric tissue failed to grow. Minimum explant sizes of 0.3 mm2 for live and ≥0.5 mm2 for cadaveric tissue had a mean expansion areas of 182.39±17.06 mm2 and 217.59±16.91 mm2 respectively suggesting adequate growth potential of the explants. Mean total percentage of proliferative cells was 31.80±3.81 in live and 33.49±4.25 in cadaveric tissue expansion. The expression was noted to be similar in cells cultured from cadaveric compared to cells cultured from live Limbal tissue with respect to ABCG2, p63α, CK(3+12) and E-cadherin. Conclusion Our findings show that a minimal amount of 0.3 mm2 live tissue would be sufficient for ample Limbal cell expansion in vitro. Cadaveric explants

  • successful autologous simple Limbal epithelial Transplantation slet in previously failed paediatric Limbal Transplantation for ocular surface burns
    Case Reports, 2013
    Co-Authors: Swapnil Bhalekar, Sayan Basu, Virender S. Sangwan
    Abstract:

    A 3-year-old child sustained severe ocular surface burns in her left eye after accidental lime injury. Despite appropriate management in the acute stage, she developed Limbal stem cell deficiency (LSCD) in that eye. This was initially treated with autologous ex vivo cultivated Limbal epithelial Transplantation (CLET), which unfortunately failed after 6 months resulting in recurrence of LSCD. One year following CLET, she underwent simple Limbal epithelial Transplantation (SLET) using autologous donor tissue from the healthy fellow eye. Successful restoration of the ocular surface following SLET combined with amblyopia therapy led to significant cosmetic and functional improvement. One year following SLET her vision in the left eye was 20/80 and she continues to maintain a stable, avascular and completely epithelised corneal surface. This case illustrates that SLET is effective in treating LSCD even in cases that are conventionally considered to be at high risk for failure of Limbal stem cell Transplantation.

  • successful management of immunological rejection following allogeneic simple Limbal epithelial Transplantation slet for bilateral ocular burns
    Case Reports, 2013
    Co-Authors: Swapnil Bhalekar, Sayan Basu, Virender S. Sangwan
    Abstract:

    A 41-year-old woman presented with bilateral total Limbal stem cell deficiency, one year after chemical injury. She underwent allogeneic simple Limbal epithelial Transplantation (SLET) from a cadaveric donor in her right eye. One month later her unaided visual acuity (VA) improved to 20/100 from hand-motions. The corneal surface was avascular and epithelialised. Three months later, she presented with acute pain in right eye with peripheral corneal neovascularisation encircling the transplants, engorged and tortuous periLimbal vessels and diffuse epithelial haze. For a diagnosis of allograft rejection, pulse doses of intravenous methyl prednisolone with intensive topical steroids were administered. Her symptoms resolved in a week, confirming the diagnosis. She recovered her pre-rejection VA. She was maintained on systemic immunosuppressive agents. Her ocular surface continues to be stable. This case describes hitherto unknown clinical features of allograft rejection following SLET and emphasises the importance of continued immunosuppression in allogeneic Limbal Transplantation.

  • Simple Limbal epithelial Transplantation (SLET): a novel surgical technique for the treatment of unilateral Limbal stem cell deficiency
    British Journal of Ophthalmology, 2012
    Co-Authors: Virender S. Sangwan, Sayan Basu, Sheila Macneil, Dorairajan Balasubramanian
    Abstract:

    This study describes a novel surgical technique of Limbal Transplantation, which combines the benefits of existing techniques while avoiding their difficulties. Six patients with unilateral and total Limbal stem cell deficiency following ocular surface burns underwent a single-stage procedure. A 2×2 mm strip of donor Limbal tissue was obtained from the healthy eye and divided into eight to ten small pieces. After surgical preparation of the recipient ocular surface, these tiny Limbal transplants were distributed evenly over an amniotic membrane placed on the cornea. After surgery, a completely epithelialised, avascular and stable corneal surface was seen in all recipient eyes by 6 weeks, and this was maintained at a mean±SD follow-up of 9.2±1.9 months. Visual acuity improved from worse than 20/200 in all recipient eyes before surgery to 20/60 or better in four (66.6%) eyes, while none of the donor eyes developed any complications. This technique requires less donor tissue than previously used for conventional autografting and does not need a specialist laboratory for cell expansion. Although long-term results are awaited, this simple Limbal epithelial Transplantation promises to be an easy and effective technique for treating unilateral Limbal stem cell deficiency following ocular burns.

Scheffer C. G. Tseng - One of the best experts on this subject based on the ideXlab platform.

  • Amniotic membrane Transplantation or conjunctival Limbal autograft for Limbal stem cell deficiency induced by 5-fluorouracil in glaucoma surgeries.
    Cornea, 2000
    Co-Authors: Renato T. F. Pires, Amit Chokshi, Scheffer C. G. Tseng
    Abstract:

    PURPOSE: To determine if human amniotic membrane Transplantation or Limbal stem cell Transplantation is effective to restore the corneal surface with partial or total Limbal stem cell deficiency, respectively, caused by 5-fluorouracil (5-FU) toxicity after glaucoma surgeries. METHODS: Partial and total Limbal stem cell deficiency was confirmed by impression cytology as the cause of reduced vision and corneal surface breakdown in a 69-year-old man and a 67-year-old man, respectively, who both had received a total of 105 mg 5-FU injections. Amniotic membrane Transplantation or conjunctival Limbal autograft was performed for corneal surface reconstruction, respectively. RESULTS: For a period of 15 months of follow-up, the visual acuity improved, and their corneal surfaces remained avascular, smooth, and without recurrence of Limbal stem cell deficiency. CONCLUSION: Limbal stem cell deficiency can occur as a late complication for patients receiving 5-FU after glaucoma filtering surgeries. Partial Limbal stem cell deficiency can be treated with amniotic membrane Transplantation alone, whereas Limbal Transplantation must be considered as an alternative for total Limbal stem cell deficiency to restore the corneal surface integrity and vision.

  • Transplantation von Ammionmembran mit oder ohne allogener LimbusTransplantation zur Rekonstruktion der kornealen Oberfläche bei Limbusinsuffizienz
    Der Ophthalmologe, 2000
    Co-Authors: Daniel Meller, Scheffer C. G. Tseng
    Abstract:

    Purpose: We examined whether amniotic membrane Transplantation (AMT) is useful in preparing the periLimbal stroma to enhance the success of allograft Limbal Transplantation (ALT). Methods: Forty-seven eyes of 42 consecutive patients with cytologically proven Limbal deficiency (LD) were included in this prospective study. Based on the severity of LD, group A (mild) with 18 eyes received AMT alone, group B (moderate) with 13 eyes received AMT and ALT, and group C (severe) with 16 eyes received AMT, ALT and penetrating keratoplasty. All except for group A received continuous systemic cyclosporin A. Results: Except for the two eyes with atopy, all amniotic membrane-covered surfaces showed rapid epithelialization in 2–4 weeks, reduced inflammation, vascularization and scarring, and became smooth. For the mean follow-up period of 23 months, 38 eyes (82.6%) showed visual improvement, consisting of >6 lines (15 eyes), 4–5 lines (10 eyes), 1–3 lines (13 eyes). Visual improvement was noted in 16/18 eyes (88.9%) in group A, in 10/13 eyes (77%) in group B, and in 12/16 eyes (75%) in group C. In group C corneal graft rejection occurred in 12 of 16 eyes (75%). In group B and C, early reversible Limbal allograft rejection was noted in 3 of 29 eyes (10.3%) and a recurrent Limbal deficiency was observed in 8 of 29 eyes (27.6%). Conclusion: For partial LD with superficial involvement, AMT alone is sufficient and hence superior to ALT because of no need for using cyclosporin A. For total LD, additional ALT is needed and AMT helps reconstruct the periLimbal stroma with reduced inflammation and vascularization, which collectively may enhance ALT success. Fragestellung: Stellenwert der Transplantation von Amnionmembran (AMT) zur Rekonstruktion des periLimbalen Stromas bei Patienten mit Limbusinsuffizienz (LI). Desweiteren wurde die Erfolgsrate der AMT mit oder ohne allogener LimbusTransplantation (aLT) bei LI analysiert. Patienten und Methode: 47 Augen von 42 Patienten mit einer zytologisch nachgewiesenen, ätiologisch unterschiedlichen LI wurden prospektiv untersucht. Die Patienten wurden in Abhängigkeit des Ausprägungsgrades der LI in drei Gruppen eingeteilt. In Gruppe A (fokale/partielle LI, 18 Augen) wurde nur eine AMT, in Gruppe B (moderate LI, 13 Augen) eine AMT und aLT und in Gruppe C (ausgeprägte, komplette LI, 16 Augen) eine AMT, aLT und perforierende Keratoplastik (pKP) durchgeführt. Mit Ausnahme der Gruppe A erfolgte bei allen Patienten eine systemische Behandlung mit Cyclosporin A. Ergebnisse: Alle bis auf 2 Augen, die als Grunderkrankung eine atopische Keratitis hatten, zeigten eine rasche Epithelialisierung (2–4 Wochen), eine reduzierte Entzündung, Vaskularisation und Narbenbildung im Bereich der von Amnionmembran gedeckten Oberfläche, die sich glatt und benetzt darstellte. In einem durchschnittlichen Nachbeobachtungszeitraum von 23 Monaten erzielten 38 Augen (82.6%) eine verbesserte Sehschärfe. In 15 Augen wurde eine Zunahme um 6 oder mehr Sehschärfenstufen (SS), in 10 Augen um 4–5 SS und in 13 Augen um 1–3 SS beobachtet. In Gruppe A zeigten 16 von 18 Augen (88.9%), in Gruppe B 10 von 13 (77%) und in Gruppe C 12 von 16 Augen (75%) eine Visuszunahme. Eine Abstoßung des Hornhauttransplantates trat in 12 von 16 Augen (75%) in Gruppe C auf. Eine frühe, reversible Abstoßung des Limbustransplantates wurde in 3 von 29 (10.3%) Augen und eine rezidivierende Limbusinsuffizienz in 8 von 29 (27.6%) Augen der Gruppen B und C beobachtet. Schlußfolgerung: Bei einer fokalen LI mit oberflächlicher Hornhautbeteiligung ist die AMT ausreichend und somit der aLT überlegen, da hier die systemische Applikation von Cyclosporin A entfällt. Bei einer ausgeprägten, kompletten LI ist eine zusätzliche aLT erforderlich und in diesen Fällen begünstigt die AMT durch Reduktion der Entzündung und Vaskularisation im periLimbalen Stroma die Prognose der LT.

  • amniotic membrane Transplantation with or without Limbal allografts for corneal surface reconstruction in patients with Limbal stem cell deficiency
    Archives of Ophthalmology, 1998
    Co-Authors: Scheffer C. G. Tseng, Pinnita Prabhasawat, Keith Barton, Trevor Gray, Daniel Meller
    Abstract:

    OBJECTIVE: To examine whether amniotic membrane Transplantation (AMT), in preparing the periLimbal stroma, enhances the success of allograft Limbal Transplantation (ALT). METHODS: Thirty-one eyes of 26 consecutive patients had cytologically proven Limbal deficiency resulting from chemical burns (14 eyes); Stevens-Johnson syndrome, toxic epidermal necrolysis, or pseudopemphigoid (5 eyes); contact lens-induced keratopathy (3 eyes); aniridia (3 eyes); multiple surgical procedures (2 eyes); atopy (2 eyes); or an unknown cause (2 eyes). Based on the severity of Limbal deficiency, group A (mild), comprising 10 eyes, received AMT alone; group B (moderate), comprising 7 eyes, received AMT and ALT; and group C (severe), comprising 14 eyes, received AMT, ALT, and penetrating keratoplasty. All patients except those in group A received continuous oral cyclosporine. RESULTS: Except for the 2 eyes with atopy, all amniotic membrane-covered surfaces showed rapid epithelialization (in 2 to 4 weeks) and reduced inflammation, vascularization, and scarring, and the surfaces became smooth and wettable. For the mean follow-up period of 15.4 months, 25 (83%) of 30 eyes showed visual improvement, consisting of 6 or more lines (13 eyes), 4 to 5 lines (6 eyes), or 1 to 3 lines (6 eyes). Visual improvement decreased with the severity of Limbal deficiency from 8 (100%) of 8 eyes in group A to 5 (71%) of 7 eyes in group B and 11 (79%) of 14 eyes in group C. In group C, corneal graft rejection occurred in 9 (64%) of 14 eyes, and reversible early Limbal allograft rejection was noted in 3 (14%) of 21 eyes of groups B and C. CONCLUSIONS: For partial Limbal deficiency with superficial involvement, AMT alone is sufficient and hence superior to ALT because there is no need to administer cyclosporine. For total Limbal deficiency, additional ALT is needed, and AMT helps reconstruct the periLimbal stroma, with reduced inflammation and vascularization, which collectively may enhance the success of ALT.

  • effect of stromal inflammation on the outcome of Limbal Transplantation for corneal surface reconstruction
    Cornea, 1995
    Co-Authors: R J Tsai, Scheffer C. G. Tseng
    Abstract:

    : Limbal Transplantation (LT) is reportedly better than conjunctival Transplantation in restoring rabbit corneal surfaces when performed 1-2 months (early stage) after severe damage. The outcome remains unclear if surgery is done at a later stage, and it is also unclear whether lamellar keratectomy should routinely be performed. Using the same rabbit model, LT was done at 3-4 months (intermediate Limbal Transplantation[ILT], n = 7) or 9-11 months (delayed Limbal Transplantation[DLT], n = 8) later. Lamellar keratectomy was also conducted with ILT in another group (keratectomy in intermediate Limbal Transplantation[IKLT], n = 7). External eye photography and fluorescein angiography were used to document corneal surface and stromal changes. The resultant epithelial phenotype was studied with AE-5 (cornea specific) and APSM-1/AM-3 (conjunctiva specific) monoclonal antibodies. As in previous studies of early Limbal Transplantation (ELT, performed at 1-2 months), ILT also had a high (eight of eight) success rate of restored corneal phenotype. In contrast, DLT yielded varying results: three of eight successes for corneal, three of eight for mixed, and two of eight for conjunctival phenotypes (p < 0.01, chi 2 trend). IKLT yielded four of seven corneal, two of seven mixed, and one of seven conjunctival phenotype successes. These results indicate that intense stromal inflammation associated with disease chronicity or additional stromal damage by lamellar keratectomy can interfere with the capability of Limbal grafts to attain normal corneal epithelial proliferation and differentiation. Future studies of how Limbal stem cells are regulated by the stromal environment are crucial to enhancing other clinical applications.

  • human allograft Limbal Transplantation for corneal surface reconstruction
    Cornea, 1994
    Co-Authors: R J Tsai, Scheffer C. G. Tseng
    Abstract:

    Limbal allograft Transplantation was performed consecutively in 16 eyes with thermal or chemical burns (n=5), Terrien's degeneration (n=2), congenital sclerocornea (n=1), Stevens-Johnson syndrome (n=1), and chronic keratoconjunctivitis (n=7), by transplanting randomly selected cadaver limbocorneal g

José Álvaro Pereira Gomes - One of the best experts on this subject based on the ideXlab platform.

  • comparative study of conjunctival Limbal Transplantation not associated with the use of amniotic membrane Transplantation for treatment of total Limbal deficiency secondary to chemical injury
    Cornea, 2014
    Co-Authors: Telma Pereira Barreiro, Myrna Serapião Dos Santos, Jeison De Nadai Barros, Ana Carolina Vieira, Rossen M Hazarbassanov, José Álvaro Pereira Gomes
    Abstract:

    Purpose:The aim of this study was to compare the outcome of conjunctival Limbal Transplantation with and without the use of amniotic membrane (AM) Transplantation for the treatment of Limbal deficiency after chemical burns to the eyes.Methods:This is a retrospective, comparative, interventional case

  • survival analysis of conjunctival Limbal grafts and amniotic membrane Transplantation in eyes with total Limbal stem cell deficiency
    American Journal of Ophthalmology, 2005
    Co-Authors: Myrna Serapião Dos Santos, José Álvaro Pereira Gomes, Ana Luisa Hoflinglima, Luiz V Rizzo, Andre Romano, Rubens Belfort
    Abstract:

    Purpose To evaluate the survival of conjunctival Limbal grafts and amniotic membrane Transplantation (AMT) for total Limbal stem cell deficiency (LSCD) and the influence of several parameters as cause of LSCD, dry eye, keratinization, eyelid abnormalities, HLA compatibility, systemic immunosuppression, and keratoplasty (PKP) on surgical outcome. Design Prospective, noncomparative, interventional case series. Methods Thirty-three eyes of 31 patients with total LSCD that underwent conjunctival Limbal grafts and AMT at the Department of Ophthalmology, Federal University of Sao Paulo were included in this study. Cumulative graft survival as well as the influence of several variables on surgical outcome was analyzed. Results Ten eyes (30%) underwent conjunctival Limbal autograft and 23 (70%) underwent conjunctival Limbal allograft from living HLA-matched donor. Graft survival was seen in 13 eyes (40%) at 1 year and in 11 eyes (33.3%) at 2 years, with a cumulative survival of 33% after a mean follow-up time of 33 months. Increase in postoperative visual acuity was observed in 20 eyes (60.6%) during this period. Marked impact on graft survival was observed for patients with Stevens-Johnson syndrome, dry eye, keratinization, eyelid abnormalities, and allogeneic conjunctival Limbal Transplantation (independently of HLA compatibility) ( P P Conclusions Conjunctival Limbal grafts associated with AMT are useful for restoring corneal epithelium phenotype in eyes with total LSCD. However, the cumulative survival declines substantially over a 2-year period. Considering all investigated variables, dry eye was the most important prognostic parameter.

  • Amniotic membrane Transplantation for partial and total Limbal stem cell deficiency secondary to chemical burn
    Ophthalmology, 2003
    Co-Authors: José Álvaro Pereira Gomes, Myrna Serapião Dos Santos, Marcelo Cunha, Vera L.úcia Degaspare Mascaro, Jeison De Nadai Barros, Luciene Barbosa De Sousa
    Abstract:

    Abstract Purpose To evaluate the surgical outcome of preserved amniotic membrane Transplantation (AMT) for ocular surface reconstruction in chemical burn with Limbal stem cell deficiency. Design Prospective, noncomparative, interventional case series. Participants Twenty eyes of 20 consecutive patients with Limbal stem cell deficiency secondary to ocular chemical injury. Intervention AMT with or without adjunctive Limbal Transplantation using Limbal tissue from either the healthy contralateral eye (CLAU) or a living related donor (lr-CLAL). Main outcome measures Reconstruction of corneal epithelium (clear appearance without epithelial defect, normal fluorescein permeability and the absence of conjunctiva-derived goblet cells on impression cytology), decrease in corneal vascularization and improvement in visual acuity. Results With a mean follow-up time of 19 months (range, 8–27 months), satisfactory ocular surface reconstruction was obtained in 15 eyes (75%), with reduced inflammation and vascularization of the ocular surface and a mean epithelialization time of 3.3 weeks. Success was observed in all cases of partial Limbal stem cell deficiency (PLD) and in 68.75% (11 eyes) of cases of total Limbal stem cell deficiency (TLD). Surgical failure was observed in five severe cases (31.25%). A significant visual improvement was observed in all cases after surgery, except for 2 eyes that maintained preoperative visual acuity. Conclusions AMT seems to be an efficient adjunct for ocular surface reconstruction in chemical burns with PLD. When performed in conjunction with Limbal stem cell Transplantation, it is also effective in most cases of TLD.

Abhinav Reddy Kethiri - One of the best experts on this subject based on the ideXlab platform.

  • optimizing the role of Limbal explant size and source in determining the outcomes of Limbal Transplantation an in vitro study
    PLOS ONE, 2017
    Co-Authors: Virender S. Sangwan, Sayan Basu, Abhinav Reddy Kethiri, Sachin Shukla, Vivek Singh
    Abstract:

    Purpose Simple Limbal epithelial Transplantation (SLET) and cultivated Limbal epithelial Transplantation (CLET) are proven clinical techniques for treating Limbal stem cell deficiency (LSCD). However, the ideal size and number of the Limbal explants required for Transplantation has not been clearly elucidated. This in vitro study aimed to determine the optimal Limbal explant size required for complete corneal epithelialization by characterizing the cell expansion. Methods Limbal explants obtained from both live and cadaveric biopsies were cultured on the denuded amniotic membrane. Explant size and the explant cell outgrowth (expansion) were measured using ImageJ software with respect to days. Cultures were characterized by assessing the rate of proliferation of cells with 5-bromo-2’-deoxyuridine (BrdU) assay along with the expression of different stem cell markers (ABCG2, p63α), corneal epithelial (CK3+12) and adherens junction molecules (E-Cadherin) by immunofluorescence. Results Explants from live biopsies had 80% growth potential in vitro whereas 40% of the cadaveric tissue failed to grow. Minimum explant sizes of 0.3 mm2 for live and ≥0.5 mm2 for cadaveric tissue had a mean expansion areas of 182.39±17.06 mm2 and 217.59±16.91 mm2 respectively suggesting adequate growth potential of the explants. Mean total percentage of proliferative cells was 31.80±3.81 in live and 33.49±4.25 in cadaveric tissue expansion. The expression was noted to be similar in cells cultured from cadaveric compared to cells cultured from live Limbal tissue with respect to ABCG2, p63α, CK(3+12) and E-cadherin. Conclusion Our findings show that a minimal amount of 0.3 mm2 live tissue would be sufficient for ample Limbal cell expansion in vitro. Cadaveric explants <0.5 mm2 had poor growth potential. However, larger explants (≥ 0.5 mm2) had growth rate and proliferative potential similar to the live tissue. These findings could prove to be critical for clinical success especially while attempting cadaveric Limbal Transplantation. This study provides a novel clinical strategy for enhancing efficacy of the Limbal Transplantation surgery and opens the probability of even using the cadaveric tissue by considering the size of explant.

  • Optimizing the role of Limbal explant size and source in determining the outcomes of Limbal Transplantation: An in vitro study.
    PLOS ONE, 2017
    Co-Authors: Abhinav Reddy Kethiri, Virender S. Sangwan, Sayan Basu, Sachin Shukla, Vivek Singh
    Abstract:

    Purpose Simple Limbal epithelial Transplantation (SLET) and cultivated Limbal epithelial Transplantation (CLET) are proven clinical techniques for treating Limbal stem cell deficiency (LSCD). However, the ideal size and number of the Limbal explants required for Transplantation has not been clearly elucidated. This in vitro study aimed to determine the optimal Limbal explant size required for complete corneal epithelialization by characterizing the cell expansion. Methods Limbal explants obtained from both live and cadaveric biopsies were cultured on the denuded amniotic membrane. Explant size and the explant cell outgrowth (expansion) were measured using ImageJ software with respect to days. Cultures were characterized by assessing the rate of proliferation of cells with 5-bromo-2’-deoxyuridine (BrdU) assay along with the expression of different stem cell markers (ABCG2, p63α), corneal epithelial (CK3+12) and adherens junction molecules (E-Cadherin) by immunofluorescence. Results Explants from live biopsies had 80% growth potential in vitro whereas 40% of the cadaveric tissue failed to grow. Minimum explant sizes of 0.3 mm2 for live and ≥0.5 mm2 for cadaveric tissue had a mean expansion areas of 182.39±17.06 mm2 and 217.59±16.91 mm2 respectively suggesting adequate growth potential of the explants. Mean total percentage of proliferative cells was 31.80±3.81 in live and 33.49±4.25 in cadaveric tissue expansion. The expression was noted to be similar in cells cultured from cadaveric compared to cells cultured from live Limbal tissue with respect to ABCG2, p63α, CK(3+12) and E-cadherin. Conclusion Our findings show that a minimal amount of 0.3 mm2 live tissue would be sufficient for ample Limbal cell expansion in vitro. Cadaveric explants