Control of Hyperglycemia Using Differentiated and Undifferentiated Mesenchymal Stem Cells in Rats with Type 1 Diabetes

Bone marrow mesenchymal stromal cell-derived small extracellular vesicles: A novel therapeutic agent in ischemic heart diseases

Myocardial injury is a major pathological factor that causes death in patients with heart diseases. In recent years, mesenchymal stromal cells (MSCs) have been generally used in treating many diseases in animal models and clinical trials. mesenchymal stromal cells have the ability to differentiate into osteocytes, adipocytes and chondrocytes. Thus, these cells are considered suitable for cardiac injury repair. However, mechanistic studies have shown that the secretomes of mesenchymal stromal cells, mainly small extracellular vesicles (sEVs), have better therapeutic effects than mesenchymal stromal cells themselves. In addition, small extracellular vesicles have easier quality control characteristics and better safety profiles. Therefore, mesenchymal stromal cell-small extracellular vesicles are emerging as novel therapeutic agents for damaged myocardial treatment. To date, many clinical trials and preclinical experimental results have demonstrated the beneficial effects of bone marrow-derived mesenchymal stromal cells (BMMSCs) and bone marrow-derived mesenchymal stromal cells-small extracellular vesicles on ischemic heart disease. However, the validation of therapeutic efficacy and the use of tissue engineering methods require an exacting scientific rigor and robustness. This review summarizes the current knowledge of bone marrow-derived mesenchymal stromal cells- or bone marrow-derived mesenchymal stromal cells-small extracellular vesicle-based therapy for cardiac injury and discusses critical scientific issues in the development of these therapeutic strategies.

Stem Cell Therapy Improves Human Islet Graft Survival in Mice via Regulation of Macrophages

Islet/β-cell transplantation offers great hope for patients with type 1 diabetes. We assessed the mechanisms of how intrahepatic coinfusion of human α-1 antitrypsin (hAAT)-engineered mesenchymal stromal cells (hAAT-MSCs) improves survival of human islet grafts posttransplantation (PT). Longitudinal in vivo bioluminescence imaging studies identified significantly more islets in the livers bearing islets cotransplanted with hAAT-MSCs compared with islets transplanted alone. In vitro mechanistic studies revealed that hAAT-MSCs inhibit macrophage migration and suppress IFN-γ-induced M1-like macrophages while promoting IL-4-induced M2-like macrophages. In vivo this translated to significantly reduced CD11c+ and F4/80+ cells and increased CD206+ cells around islets cotransplanted with hAAT-MSCs as identified by multiplex immunofluorescence staining. Recipient-derived F4/80+and CD11b+ macrophages were mainly present in the periphery of an islet, while CD11c+ and CD206+ cells appeared inside an islet. hAAT-MSCs inhibited macrophage migration and skewed the M1-like phenotype toward an M2 phenotype both in vitro and in vivo, which may have favored islet survival. These data provide evidence that hAAT-MSCs cotransplanted with islets remain in the liver and shift macrophages to a protective state that favors islet survival. This novel strategy may be used to enhance β-cell survival during islet/β-cell transplantation for the treatment of type 1 diabetes or other diseases.

Alloreactive Immune Response Associated to Human Mesenchymal Stromal Cells Treatment: A Systematic Review

The well-known immunomodulatory and regenerative properties of mesenchymal stromal cells (MSCs) are the reason why they are being used for the treatment of many diseases. Because they are considered hypoimmunogenic, MSCs treatments are performed without considering histocompatibility barriers and without anticipating possible immune rejections. However, recent preclinical studies describe the generation of alloantibodies and the immune rejection of MSCs. This has led to an increasing number of clinical trials evaluating the immunological profile of patients after treatment with MSCs. The objective of this systematic review was to evaluate the generation of donor specific antibodies (DSA) after allogeneic MSC (allo-MSC) therapy and the impact on safety or tolerability. Data from 555 patients were included in the systematic review, 356 were treated with allo-MSC and the rest were treated with placebo or control drugs. A mean of 11.51% of allo-MSC-treated patients developed DSA. Specifically, 14.95% of these patients developed DSA and 6.33% of them developed cPRA. Neither the production of DSA after treatment nor the presence of DSA at baseline (presensitization) were correlated with safety and/or tolerability of the treatment. The number of doses administrated and human leucocyte antigen (HLA) mismatches between donor and recipient did not affect the production of DSA. The safety of allo-MSC therapy has been proved in all the studies and the generation of alloantibodies might not have clinical relevance. However, there are very few studies in the area. More studies with adequate designs are needed to confirm these results.