Browsing by Author "Patel, H."

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Differentiation of human male germ cells from Wharton's jelly-derived mesenchymal stem cells
(Korean Society for Reproductive Medicine, 2018) Dissanayake, D.M.A.B.; Patel, H.; Wijesinghe, P.S.
OBJECTIVE: Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium. METHODS: Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at 36℃ for 3 more weeks. RESULTS: The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf(early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted. CONCLUSION: Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.
Differentiation of male germ cells from human umbilical cord blood derived mesenchymal stem cells
(Faculty of Graduate Studies, University of Kelaniya, 2015) Dissanayake, D.M.A.B.; Wijesinghe, P.S.; Patel, H.
Rationale: Modelling the process of spermatogenesis is significant in elucidating important mechanisms such as reduction in ploidy, chromatin repackaging, initiation of motility, expression of different genes etc. Stem cell researchers are accumulating more data favouring towards the hopes of infertile males. Aim: To differentiate male germ cells using mesenchymal stem cells (MSCs) isolated from human umbilical cord blood. Methodology: MSCs from umbilical cord blood were isolated, expanded and characterized using standard protocols. The cells at the second passage were induced with 10 μM All Trans Retinoic Acid (ATRA) for two weeks. Stage specific genes expressed or suppressed at premeiotic, meiotic and post-meiotic stages were detected using Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) technique, before and after the ATRA treatment. Morphological changes were assessed microscopically. Results: OCT4 a stem cell marker, and PLZF an early Spermatogonial Stem Cells (SSCs) marker, were down regulated during the induction period. Expression of other germ cell markers; pre-meiotic (Stra8), meiotic (Scp3) and post-meiotic (Acr, Prm1, Tekt1) were up regulated. However, morphological changes related to specific cell lineage were difficult to differentiate. Conclusion: Human cord blood derived MSCs can differentiate in to germ like cells without genetic manipulation. Further studies are designed to improve the efficacy of the culture system using sertoli cells and hormones.
Stem cells and its clinical applications
(Faculty of Medicine, University of Kelaniya, Sri Lanka, 2016) Patel, H.
The concept of stem cells was introduced by Alexander Maximow in the year 1909. Stem cells comprise of "primitive cells" that have the ability to divide indefinitely and give rise to specialized cells under specific conditions. Because of these two distinct characteristics they have received particular attention in recent decades. Stem cells have very potent clinical application in treating cardiovascular, pulmonary, spinal cord, skin, burns and wounds, gynaecological and orthopaedic disorders. Stem cells have proven to be a very good source for treating thin endometrium that could be one of the factors for infertility in women. Endothelial progenitor cells (EPCs) improve vascular blood supply and incorporated into neovessels at sites of damage and significantly improved blood flow. EPCs regenerate the endometrial epithelium with its vascularity and make it mature enough for implantation. Recent findings suggest that ovaries contain stem cells which form new oocytes in adulthood and these can be cultured in-vitro to form mature oocytes. These findings provide new hope for fertility preservation. Even the advances in the technology has achieved to develop germ cells from pluripotent stem cells through iPS. Currently there are limited established clinical application though the research is going on using different type of cells for various different clinical conditions.