Islet-specific microRNAs in pancreas development, regeneration and diabetes.

Diabetes is a chronic and slowly progressive disease that is presently reaching epidemic proportions in several parts of the world. Multiple aspects including genetic and lifestyle changes have been identified as the key factors leading to the development of type 1 and type 2 diabetes. Although molecular mechanisms underlying the pathogenesis of diabetes remain unclear, recent discoveries in understanding post-transcriptional gene regulation by microRNAs (miRNAs) has opened a new area of research. MicroRNAs have been implicated as new players in pathogenesis as well as complications of diabetes. MiRNAs have been shown to be necessary not only during embryonic development of insulin-producing cells, transcription of (pro-)insulin gene and insulin secretion, but also in development of insulin resistance and diabetes. The present review summarizes the findings related to understanding the role of miRNAs in endocrine pancreas development, pancreas regeneration, islet function and diabetes.

Growth modulation of fibroblasts by chitosan-polyvinyl pyrrolidone hydrogel: implications for wound management?

Wounds in adults and fetuses differ in their healing ability with respect to scar formation. In adults, wounds lacking the epidermis exhibit excess collagen production and scar formation. Fibroblasts synthesize and deposit a collagen rich extracellular matrix. The early migration and proliferation of fibroblasts in the wound area is implicated in wound scarring. We have synthesized a hydrogel from chitosan-polyvinyl pyrrolidone (PVP) and examined its effect on fibroblast growth modulation in vitro. The hydrogel was found to be hydrophilic as seen from its octane contact angle (141.2+/-0.37 degrees). The hydrogel was non-toxic and biocompatible with fibroblasts and epithelial cells as confirmed by the 3(4,5-dimethylthiazolyl-2)-2, 5-diphenyl tetrazolium bromide (MTT) as-say. It showed dual properties by supporting growth of epithelial cells (SiHa) and selectively inhibiting fibro-blast (NIH3T3) growth. Growth inhibition of fibroblasts resulted from their inability to attach on to the hydrogel. These findings are supported by image analysis, which revealed a significant difference (P<0.05) between the number of fibroblasts attached to the hydrogel in tissue culture as compared to tissue culture treated polystyrene (TCPS) controls. However, no significant difference was observed (P>0.05) in the number of epithelial (SiHa) cells attached on to the hydrogel as compared to the TCPS control. Although in vivo experiments are awaited, these findings point to the possible use of chitosan-PVP hydrogels in wound-management.