Bone regeneration is considered as an unmet clinical need, the aim of this study is to investigate the osteogenic potential of three different mesenchymal stem cells (MSCs) derived from human bone marrow (BM-MSCs), umbilical cord Wharton's jelly (UC-MSCs), and adipose (AD-MSCs) seeded on a recently developed nanocomposite scaffold (bioactive glass/ gelatin) implanted in rat animal models with critical size calvarial defects. In this study, after isolation, culture, and characterization, the MSCs were expanded and seeded on the scaffolds for in vitro and in vivo studies. The adhesion, proliferation, and viability of the cells on the scaffolds evaluated in vitro, showed that the scaffolds were biocompatible for further examinations. In order to evaluate the scaffolds in vivo, rat animal models with critical size calvarial defects were randomly categorized in four groups and treated with the scaffolds. The animals were sacrificed at the time points of 4 and 12 weeks of postimplantation, bone healing process were investigated. The histological and immunohistological observations showed (p < 0.01) higher osteogenesis capacity in the group treated with BM-MSCs/scaffolds compared to the other groups. However, the formation of new angiogenesis was evidently higher in the defects filled with UC-MSCs/scaffolds. This preliminary study provides promising data for further clinical trials.

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Type 1 diabetes mellitus (T1DM) is an autoimmune disorder that leads to beta cell destruction and lowered insulin production. In recent years, stem cell therapies have opened up new horizons to treatment of diabetes mellitus. Among all kinds of stem cells, mesenchymal stem cells (MSCs) have been shown to be an interesting therapeutic option based on their immunomodulatory properties and differentiation potentials confirmed in various experimental and clinical trial studies. In this review, we discuss MSCs differential potentials in differentiation into insulin-producing cells (IPCs) from various sources and also have an overview on currently understood mechanisms through which MSCs exhibit their immunomodulatory effects. Other important issues that are provided in this review, due to their importance in the field of cell therapy, are genetic manipulations (as a new biotechnological method), routes of transplantation, combination of MSCs with other cell types, frequency of transplantation, and special considerations regarding diabetic patients' autologous MSCs transplantation. At the end, utilization of biomaterials either as encapsulation tools or as scaffolds to prevent immune rejection, preparation of tridimensional vascularized microenvironment, and completed or ongoing clinical trials using MSCs are discussed. Despite all unresolved concerns about clinical applications of MSCs, this group of stem cells still remains a promising therapeutic modality for treatment of diabetes.

BackgroundCalcitriol is documented to cause significant increase in bone mass densitometry counteracting osteoporosis. Promising results of calcitriol supplementation in studies aiming space flight induced osteoporosis is little and the effect of this hormone on biomarkers of bone metabolism is not examined yet in space flight models of osteoporosis in rats.MethodsThis was an interventional animal study being performed in a 1-month period. We included 21 Sprague Dawley strain rats (>200 gr, >6 week) who were randomly assigned to receive daily supplementation of oral 0.03μgr calcitriol and to be submitted to tail suspension model. Rats were followed for 1 month and were tested for serum osteocalcin (OC), alkaline phosphatase (ALP) and serum calcium at the beginning and the end of the study period. The results were analyzed and compared between groups.ResultsAlthough serum levels of osteocalcin and alkaline phosphatase biomarkers and total serum calcium were not significantly different within and between study groups, their levels were increased in tail suspension model compared to control group. The levels of these biomarkers were lower in those who were submitted to tail suspension model and received calcitriol supplementation compared to those who were only submitted to tail suspension (60.14 ± 11.73 ng/mL vs. 58.29 ± 2.69 ng/mL; p = 0.696 for osteocalcin and 381.86 ± 99.16 mU/mL vs. 362.57 ± 27.41 ng/mL; p = 0.635 for alkaline phosphatase).ConclusionSupplementation of daily diet with calcitriol in rats under weightlessness conditions may results in lower values for bone metabolic biomarkers of alkaline phosphatase and osteocalcin and serum calcium. This pattern of change in biomarkers of bone formation, may point to the capacity of calcitriol supplementation in preventing cellular process of osteoporosis. Thus calcitriol supplementation could be an available, economic and effective strategy for preventing bone metabolic changes related to weightlessness commonly encountered in space flight. The outcome of this study needs to be further studied in future trying to find more definite results.

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