== Wound healing rate is decreased in diabetic limbal epithelial cells compared to healthy ones as revealed by scratch wound assay in the presence of 1 and 4 ng/ml epidermal growth factor. A: Wound healing in the presence of 1 and 4 ng/ml EGF was evaluated by measuring wound areas for healthy (NL) and diabetic (DM) LEC using ImageJ software and presented as percentage of wound area for healthy (NL) and diabetic (DM) LEC using ImageJ software and presented as percentage of wound area coverage standard error of mean. markers, whereas no expression was detected for differentiated corneal epithelial cell marker K12. Decreased expression of LESC markers was observed in diabetic LECs compared to healthy LECs cultured on the FCL-coated slides. 4-Aminobenzoic acid This reduction was most prominent for K15 and K17. Diabetic LECs were found to heal scratch wounds slower than healthy cells in accordance with previous results in corneal organ cultures. == Conclusions == Healthy human LECs cultured either on AM or FCL-coated slides preserved LESC marker expression. The observed reduction in LESC marker expression and slower wound healing in cultured diabetic LECs are in line with our earlier reports and may account for diabetic LESC dysfunction and clinically observed impaired corneal epithelial wound healing. == Introduction == Corneal blindness is the second most common devastating eye disorder, affecting more than 6 million people worldwide [1, 2]. In pathological conditions associated with diabetes mellitus (DM), the cornea is affected by such complications as neurotrophic corneal ulcers, loss of corneal sensation, keratitis, and a characteristic epithelial dystrophy called diabetic keratopathy [3-8]. The diabetic cornea displays reduced numbers of hemidesmosomes [3, 4], edema 4-Aminobenzoic acid [9, 10], altered growth factor signaling [5], basement membrane abnormalities [11], and 4-Aminobenzoic acid delayed wound healing leading to persistent epithelial defects [12, 13]. In humans, corneal epithelial wound healing and renewal mainly depend on stem cells that reside in the basal epithelial layer of the corneoscleral junction (the limbus) [14-19]. Defects of these limbal epithelial stem cells (LESCs) may have serious adverse effects on corneal function such as conjunctival in-growth and neovascularization of the corneal stroma, which often lead to corneal opacity and vision loss [20-22]. Dysfunction of the limbal niche and its resident LESCs could be responsible for various abnormalities in the diabetic corneal epithelium due to their role in epithelial renewal and wound healing. Previously, we found that overexpression of hepatocyte growth factor (HGF) receptor tyrosine kinase c-met and/or silencing of matrix metalloproteinase-10 (MMP-10) and cathepsin F in organ-cultured diabetic corneas could normalize epithelial marker expression, as well as wound healing time [23-25]. Additionally , we examined various putative stem cell markers in ex festn diabetic and healthy limbal Mouse monoclonal to CD63(PE) epithelia and showed that the immunostaining patterns of several stem cell markers were altered in the diabetic limbus [26], which could potentially be corrected with gene therapy [24, 25]. These data suggest that the limbal compartment may play an important role in diabetic corneal alterations that can be ameliorated with gene therapy. Therefore , it is important to confirm whether cultured limbal epithelial cells preserve stem marker expression abnormalities described earlier in organ-cultured corneas and thus can be used to study diabetes-associated corneal alterations. If this assumption proved to be correct, cultured diabetic cells could be used for gene therapy for potential transplantation to diseased corneas in cases of severe diabetic LESC dysfunction exacerbated by diabetic corneal neuropathy [8, 13]. To this end, we examined limbal epithelial stem marker expression and wound healing in primary healthy and diabetic LECs 4-Aminobenzoic acid cultured on different substrata. We found that human LECs cultured either on denuded human amniotic membrane (AM) or extracellular matrix-coated dishes preserved LESC marker expression patterns in healthy and diabetic cells. Reduced LESC marker expression and wound healing rates were observed in the cultured diabetic LECs. This is in 4-Aminobenzoic acid agreement with our earlier reports on alterations in human diabetic corneas, which may account for diabetic LESC dysfunction and impaired corneal epithelial wound healing. == Methods == == LEC isolation == Primary LEC cultures were prepared from human healthy and diabetic postmortem corneas and whole globes.