| 研究実績の概要 |
For the last 6 days of the differentiation, tooth pulp cells were exposed to 0.1ng/mL H2S. Immunocytochemistry, RT-PCR, determination of insulin content, and flow-cytometry of pancreatically-related markers were carried out. Expression of WNT and the PI3K/AKT signaling pathway were also determined by PCR array. After differentiation, insulin, glucagon, somatostatin and pancreatic polypeptide were positive, examined by immunofluorescence and flow-cytometry. Only the cells expressing insulin increased after H2S exposure. The cells expressing glucagon was significantly decreased. Genes involved in canonical WNT and the WNT/calcium pathway were highly expressed after H2S exposure. H2S accelerated insulin synthesis and secretion by regenerated insulin producing cells from human tooth. All functions of the PI3K-AKT signaling pathway were extremely activated by H2S exposure.The matured insulin-producing cells originated human tooth were increased but glucagon-producing cells were suppressed by physiological or lower concentrations of H2S. Low concentrations of H2S could be used to increase the number and function of insulin-producing cells from human tooth in order to control blood-glucose level.
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| 今後の研究の推進方策 |
The only shortcoming is that it is not easy to obtain large enough numbers of the differentiated cells at high purity without contamination with undifferentiated cells. Overcoming this deficiency is essential for establishing a regenerative protocol using in vitro differentiation of adult stem cells. Hence, at present the adult stem cells themselves are transplanted into lesions in organs, e.g. the transplantation of bone-marrow stem cells into a myocardial-infarction lesion, since a niche for the stem cells is expected to be there, and as the cells able to regenerate the tissue [22]. If the transplantation is unsuccessful, the cells might produce a teratoma or a malignant tumor.
Our previous study demonstrated that the use of dental pulp is one of the safest sources for regenerative medicine, and it is easily accessible compared with hBMC [11]. When we differentiated hDTPSC into hepatocyte-like cells, the purity of the hepatocyte-like cells after differentiation was almost 100%. Moreover, our cells require no niche, since they are differentiated enough in vitro. We found that the cells produce ectopic liver tissue in a different organ after transplantation into animals, implying that our cells involve no possibility, or much less, of inducing failures such as tumor formation.However we did not find how to prevent from apoptosis. Our preriminary study showed that H2S my disturb apoptotic process. Anti-oxidants mnay also prevent it. In this year we make it clear, and prepare for animal translantation with diabetis.
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