Transplantation of insulin-producing cells derived from human MSCs to treat diabetes in a non-human primate model.

BACKGROUND: Islet cell transplantation is an emerging therapy in the treatment of diabetes mellitus. Differentiation of islet cells from mesenchymal stem cells (MSCs) is a potential solution to the challenge of insufficient donor sources. This study investigated whether human umbilical cord-derived MSCs could effectively differentiate into insulin-producing cells (IPCs) and evaluated the therapeutic efficacy of IPCs in treating diabetes. METHODS: IPCs were induced from MSCs by a two-step protocol. IPC expression products were evaluated by western blot and real-time PCR. IPC insulin secretion was evaluated by ELISA. The viability of IPCs was measured by FDA/PI and dithizone staining. The non-human primate tree shrew was used as a diabetes model. After a single STZ induction into a diabetes model, a single intraportal transplantation of IPCs, MSCs, or normal saline was performed (n = 6 per group). Blood glucose was monitored for 3 weeks, then the animals were euthanized and the distribution of IPCs in the liver was examined pathologically. RESULTS: After about 3 weeks of in vitro induction, IPCs formed microspheres of 100-200 µm, with >95% viable cells that were dithizone stain positive. IPCs expressed islet-related genes and proteins and secreted high levels of insulin whether stimulated by low or high levels of glucose. After transplantation of IPCs into diabetic tree shrews, blood glucose levels decreased rapidly to near normal and were significantly lower than the MSC or saline groups for 3 weeks thereafter. CONCLUSION: We present the novel discovery that IPCs derived from human umbilical cord MSCs exert a therapeutic effect in a non-human primate model of diabetes. This study provides a preliminary experimental basis for the use of autologous MSC-derived IPCs in the treatment of human diabetes.

Protein-Degrading Enzymes in Osteoarthritis.

OBJECTIVE: TGFß1 plays an important role in the metabolism of articular cartilage and bone; however, the pathological mechanism and targets of TGFß1 in cartilage degradation and uncoupling of subchondral bone remodeling remain unclear. Therefore, in this study, we investigated the relationship between TGFß1 and major protein-degrading enzymes, and evaluated the role of high levels of active TGFß1 in the thickening of subchondral bone and calcification of articular cartilage. MATERIALS AND METHODS: The expression of TGFß1 and protein-degrading enzymes in clinical samples of articular cartilage and subchondral bone obtained from the knee joint of patients with osteoarthritis was detected by immunohistochemistry. The expression levels of TGFß1, MMP-3, MMP-13 and IL-1ß in cartilage and subchondral bone tissues were detected by absolute real-time quantitative RT-PCR. The expression of TGFß1, nestin and osterix in subchondral bone was detected by Western blot analysis and immunohistochemistry. The degree of subchondral bone thickening was determined by micro-computed tomography (CT) imaging. RESULTS: Expression of TGFß1 and cartilage-degrading enzymes was higher in the cartilage-disrupted group than that in the intact group. Furthermore, expression of TGFß1, nestin and osterix was significantly higher in the OA group than that in the control group. Micro-CT imaging showed that in the OA group, the subchondral bone plate is thickened and the density is increased. The trabecular bone structure is thick plate-like structure, the thickness of the trabecular bone is increased and the gap is small. CONCLUSIONS: The data suggest that highly active TGFß1 activates the expression of cartilage-degrading enzymes. Abnormally activated TGFß1 may induce formation of the subchondral bone and expansion of the calcified cartilage area, eventually leading to degradation of the cartilage tissue.