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AIM:To evaluate the epidemiological and etiological factors of microbial keratitis seen in tertiary hospitals in West and East Malaysia.METHODS:A total of 207 patients were enrolled.Patients referred for microbial keratitis to Sungai Buloh Hospital and Kuala Lumpur Hospital in West Malaysia and Queen Elizabeth Hospital and Kuching General Hospital in East Malaysia were recruited.Risk factors were documented.Corneal scrapings for microscopy and culture were performed.RESULTS:The most common risk factor in West Malaysia was organic trauma (28.5％) followed by non organic trauma (18.3％);27.7％ of trauma cases was work related with 34.2％ involving male foreign workers.The most common risk factor in East Malaysia was contact lens wear (32.9％).Pseudomonas aeruginosa was the most common organism isolated in both places.The most common fungal pathogen in West Malaysia was Fusarium spp representing 60％ of all positive fungal cultures.CONCLUSION:In West Malaysia organic trauma was the most common risk factor seen in public hospitals here whereas,contact lens wear was the most common risk factor in East Malaysia (P＜ 0.05).Fungal keratitis was more commonly seen in West Malaysia.
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PURPOSE: The presence of multipotent human limbal stromal cells resembling mesenchymal stromal cells (MSC) provides new insights to the characteristic of these cells and its therapeutic potential. However, little is known about the expression of stage-specific embryonic antigen 4 (SSEA-4) and the embryonic stem cell (ESC)-like properties of these cells. We studied the expression of SSEA-4 surface protein and the various ESC and MSC markers in the ex vivo cultured limbal stromal cells. The phenotypes and multipotent differentiation potential of these cells were also evaluated. METHODS: Limbal stromal cells were derived from corneoscleral rims. The SSEA-4(+) and SSEA-4(-) limbal stromal cells were sorted by fluorescence-activated cells sorting (FACS). Isolated cells were expanded and reanalyzed for their expression of SSEA-4. Expression of MSC and ESC markers on these cells were also analyzed by FACS. In addition, expression of limbal epithelial and corneal stromal proteins such as ATP-binding cassette sub-family G member 2 (ABCG2), tumour protein p63 (p63), paired box 6 (Pax6), cytokeratin 3 (AE5), cytokeratin 10, and keratocan sulfate were evaluated either by immunofluorecence staining or reverse transcription polymerase chain reaction. Appropriate induction medium was used to differentiate these cells into adipocytes, osteocytes, and chondrocytes. RESULTS: Expanded limbal stromal cells expressed the majority of mesenchymal markers. These cells were negative for ABCG2, p63, Pax6, AE-5, and keratocan sulfate. After passaged, a subpopulation of these cells showed low expression of SSEA-4 but were negative for other important ESC surface markers such as Tra-1-60, Tra-1-81, and transcription factors like octamer-binding transcription factor 4 (Oct4), SRY(sex determining region Y)-box 2 (Sox2), and Nanog. Early passaged cells when induced were able to differentiate into adipocytes, osteocytes and chondrocytes. CONCLUSIONS: The expanded limbal stromal cells showed features of multipotent MSC. Our study confirmed the expression of SSEA-4 by a subpopulation of cultured limbal stromal cells. However, despite the expression of SSEA-4, these cells did not express any other markers of ESC. Therefore, we conclude that the cells did not show properties of ESC.
