Abstract
Purpose:
Mesenchymal stem cells (MSCs) derived from human umbilical cord (UMSCs) are capable of treating congenital cornea disorders. The diversity of isolation methods and culture conditions, as well as the inter-individual cord variation may cause inconsistency in the therapeutic efficacy of MSCs in curing eye diseases. The purpose of this study is to develop an approach that enabling the consistent isolation of high quality UMSCs suitable for treating disease.
Methods:
UMSCs were isolated using different protocols such as tissue explant culture, cell suspension by enzyme digestion using collagenase, collagenase/trypsin or collagenase/hyluoronidase followed by culture in alpha minimal essential medium supplemented with 10% fetal bovine serum. Cells at different passages were analyzed for cell surface markers CD105, CD90, CD44, CD45 and CD31 by flow cytometry, heparin sulfate using immunofluorescent staining and cell lineage differentiation potential using osteogenesis and adipogenesis tests. The therapeutic capacity of UMSCs was determined by their efficacy to restore corneal transparency following alkali burn. Mouse corneas were injured by the application of a 2 mm filter paper disc soaked in 0.1 N NaOH for 1 minute. The injured corneas were treated with either UMSCs or PBS by intrastromal injection into the cornea one day after alkali burn. The cornea was examined by stereomicroscopy every week after transplantation.
Results:
Flow cytometry revealed subtle variation in the expression profile of the CD markers, e.g., CD105+/CD90+/CD44+/CD45-/CD31- among UMSCs purified by different protocols and harvested at different passages. However, the heparan sulfate (HS) staining showed some UMSCs exhibited punctate signals, while others displayed dense and diffuse staining. Interestingly, cells with punctate HS signals have more differentiation potential to the osteogenic and adipogenic lineage. Moreover, UMSCs having a higher differentiation potential were more effective in restoring corneal transparency.
Conclusions:
Cell marker analysis is less indicative in terms of evaluating the treatment efficacy of UMSCs. The punctate HS staining pattern and the higher differentiation capacity of UMSCs seemed to correlate with higher therapeutic efficacy. Cornea alkali burn mouse model could be used to evaluate the quality of UMSCs suitable for treating corneal diseases and other applications as well.
Keywords: 480 cornea: basic science •
721 stem cells