The Antigenicity of Ex Vivo Cultivated Human Corneal Limbal Epithelial and Stromal Cells: Temporal Changes In Vitro

Identification and characterization of dendritic cell subtypes in preserved and cultured cadaveric human corneolimbal tissue on amniotic membrane

PURPOSE

Rejection is the leading cause of failure of limbal allogafts. Resident dendritic cell (DC) maturation plays a critical role in host allosensitization. There are two lineages: myeloid (mDC) and lymphoid (pDC), with different biological properties. The aim was to analyse the distribution of DC subtypes in limbal explant cultures on amniotic membrane (AM), cultivated on either the epithelial or stromal side and to compare the results with directly isolated cells from cadaveric whole corneoscleral tissue divided into specific areas.

METHODS

The expression of CD11c (mDC), CD303/CD123 (pDC) and costimulatory molecules CD80, CD86 and activation markers HLA-DR, CD83 was investigated by flow cytometry. Additionally, the corneal epithelium marker CK12 and ABCB5, a new epithelial stem cell marker, were investigated.

RESULTS

Cells positive for pDC and mDC markers were found in all examined areas, with a nonsignificant prevalence of pDC. In limbal explant cultures on AM, the percentage of pDC and mDC was similar, with no statistically significant difference between cultures on epithelial or stromal sides of AM. However, with ex vivo limbal explant cultivation on AM, the pDC content declined significantly (p < 0.05) and the ABCB5 marker was likewise statistically significantly reduced.

CONCLUSION

This is the first study to characterize the distribution of pDC and mDC subsets in cultured and noncultured human corneolimbal tissue. Additionally, ABCB5 positive cells were identified. These findings might be important for future strategies, allowing preparation of corneolimbal allografts with optimal stem cell content for a longer lasting therapeutic effect.

Inflammation-associated lymphangiogenesis: a double-edged sword?

Lymphangiogenesis and lymphatic vessel remodeling are complex biological processes frequently observed during inflammation. Accumulating evidence indicates that inflammation-associated lymphangiogenesis (IAL) is not merely an endpoint event, but actually a phenomenon actively involved in the pathophysiology of various inflammatory disorders. The VEGF-C/VEGFR-3 and VEGF-A/VEGF-R2 signaling pathways are two of the best-studied pathways in IAL. Methods targeting these molecules, such as prolymphangiogenic or antilymphatic treatments, were found to be beneficial in various preclinical and/or clinical studies. This Review focuses on the most recent achievements in the fields of lymphatic biology relevant to inflammatory conditions. Additionally, preclinical and clinical therapies that modulate IAL are summarized.

Electroporating Human Corneal Epithelial Cells With Interleukin 10 and Fas Ligand pDNA

PURPOSE

To develop an optimal electroporation protocol for plasmid (pDNA) transfection of a human corneal epithelial cell (hCEC) line and investigate the immunomodulatory capacity of interleukin 10 and Fas ligand (FasL) transfection on hCECs.

DESIGN

A controlled experimental study.

METHODS

Human corneal epithelial cells were electroporated with pDNA encoding enhanced green fluorescent protein, interleukin 10, or FasL. Supernatants were analyzed for cytokine secretion using enzyme-linked immunosorbent assay. To test potential immunosuppression, electroporated hCECs were cocultured with allogeneic peripheral blood mononuclear cells, and the supernatants analyzed for interferon γ production.

RESULTS

Maximum transfection efficiencies were obtained using optimized settings, and transgene expression was detected up to 13 days following transfection. Interleukin 10 levels peaked at day 4 and FasL at day 2 following electroporation. Coculture supernatants showed significantly lower levels of interferon γ in the modulated groups compared with control.

CONCLUSIONS

Our results demonstrate highly efficient transfection of hCECs using an optimized electroporation protocol. Interleukin 10 and FasL may provide a means of immune modulation of corneal epithelial cells.

Characteristics of immune rejection after allogeneic cultivated limbal epithelial transplantation

PURPOSE

To investigate the characteristics and prognosis of immune rejection after allogeneic cultivated limbal epithelial transplantation (CLET).

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

Forty-two eyes of 41 patients undergoing allogeneic CLET for total limbal stem cell deficiency who completed a follow-up of at least 12 months.

METHODS

Allogeneic cultivated limbal epithelial cells using human amniotic membrane as a carrier were transplanted into the recipient eye. Immune rejection occurred in 10 eyes; the medical records of these patients were reviewed.

MAIN OUTCOME MEASURES

Best-corrected visual acuity, corneal opacification and neovascularization, immunofluorescence staining of CD4 and CD8 T cells, and distribution of Langerhans cells (LCs) in the corneal epithelium.

RESULTS

The corneal epithelium became edematous with epithelial rejection lines and peripheral epithelial defects in 6 eyes. Circumlimbal vessels were hyperemic and extended up to the corneal stroma, thus resulting in aggravation of corneal neovascularization in 8 eyes. Corneal stromal opacification was observed in 9 eyes. CD4(+) or CD8(+) T cells were detected in 5 of 6 eyes from which impression cytology specimens were obtained. In vivo confocal microscopy examination revealed an accumulation of LCs in the central and peripheral corneal epithelium. All patients responded to antirejection therapy. One eye developed a second episode.

CONCLUSIONS

The diagnosis of immune rejection after allogeneic CLET mainly depends on typical clinical manifestations. Delayed recognition can result in worsening corneal opacification and neovascularization. Reasonable use of topical immunosuppressives and a close follow-up within 6 months after allogeneic CLET are critical to improve the prognosis.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Lymphangiogenesis may play a role in cultivated limbal stem cell transplant rejection

We describe the clinicopathologic findings in a case of acute rejection following cultivated limbal stem cell transplantation (CLSC). This is the first time lymphangiogenesis has been described in CLSC rejection. This indicates that 1. absence of corneal stromal cells or 2. down regulation of HLA antigens by exposure to culture conditions, does not reduce the risk of graft rejection when transplanting into a high risk corneal bed. Our findings highlight the need for development of anti-lymphangiogenic treatments prior to CLSC transplantation.