Introduction Critical limb ischemia (CLI) is the most advanced form of peripheral arterial disease (PAD) characterized by ischemic rest pain and non-healing ulcers. Currently, the standard therapy for CLI is the surgical reconstruction and endovascular therapy or limb amputation for patients with no treatment options. Neovasculogenesis induced by mesenchymal stem cells (MSCs) therapy is a promising approach to improve CLI. Owing to their angiogenic and immunomodulatory potential, MSCs are perfect candidates for the treatment of CLI. The purpose of this study was to determine and compare the in vitro and in vivo effects of allogeneic bone marrow mesenchymal stem cells (BM-MSCs) and adipose tissue mesenchymal stem cells (AT-MSCs) on CLI treatment. Methods For the first step, BM-MSCs and AT-MSCs were isolated and characterized for the characteristic MSC phenotypes. Then, femoral artery ligation and total excision of the femoral artery were performed on C57BL/6 mice to create a CLI model. The cells were evaluated for their in vitro and in vivo biological characteristics for CLI cell therapy. In order to determine these characteristics, the following tests were performed: morphology, flow cytometry, differentiation to osteocyte and adipocyte, wound healing assay, and behavioral tests including Tarlov, Ischemia, Modified ischemia, Function and the grade of limb necrosis scores, donor cell survival assay, and histological analysis. Results Our cellular and functional tests indicated that during 28 days after cell transplantation, BM-MSCs had a great effect on endothelial cell migration, muscle restructure, functional improvements, and neovascularization in ischemic tissues compared with AT-MSCs and control groups. Conclusions Allogeneic BM-MSC transplantation resulted in a more effective recovery from critical limb ischemia compared to AT-MSCs transplantation. In fact, BM-MSC transplantation could be considered as a promising therapy for diseases with insufficient angiogenesis including hindlimb ischemia.

Background: MicroRNA-126, a microRNA implicated in blood vessel integrity and angiogenesis is significantly up/down regulated in different physiological and pathological conditions related to angiogenesis such as cardiovascular formation and angiogenesis dependent diseases like Cancer, diabetic microvascular complication, cardiovascular disease, atherosclerosis and stroke. MicroRNA-126 plays a critical role in angiogenesis via regulating the proliferation, differentiation, migration, and apoptosis of angiogenesis related cells such as endothelial cells, vascular smooth muscle cells and pericytes. Objective: The aim of this review is to investigate the molecular mechanisms and effects of microRNA-126 in angiogenesis process in pathophysiological conditions. Methods: To conduct this review, related articles published between 2001 and 2019 were collected from the PubMed, Web of Science, Google Scholar, Scopus and Scientific Information Database using search terms such as microRNA-126, angiogenesis, cardiovascular disorders, hypoxia, VEFG-A, endothelial cells, VEGF pathway, gene silencing. Then, the qualified articles were reviewed. Result: MicroRNA-126 regulates the response of endothelial cells to VEGF, through directly repressing multiple targets, including Sprouty-related EVH1 domain-containing protein 1 (SPRED1) and phosphoinositol-3 kinase regulatory subunit 2 (PIK3R2/p85-b). MicroRNA-126 -3p and microRNA-126 -5p have cell-type and strand-specific functions and also various targets in angiogenesis that lead to regulate angiogenesis via different pathways and consequently diverse response. Conclusion: MicroRNA-126 can bind to multiple targets and potentially be both positive and negative regulators of gene expression. Thus, microRNA-126 could cause the opposite biological effects depending on the context. As a result, understanding the different cellular pathways that microRNA-126 regulate angiogenesis through them in various situations is a critical aspect in the development of novel and effective treatments for diseases with insufficient angiogenesis. So it is critical to understand its role in governing angiogenesis during pathological and even physiological conditions.

No abstract

Introduction: Critical limb ischemia (CLI) considered as the most severe form of peripheral artery disease (PAD). Current therapy for CLI are surgical reconstruction and endovascular therapy or limb amputation (for patients with no treatment options). Neovasculogenesis induced by stem cells including mesenchymal stem cells (MSCs) therapy is a promising approach to treat CLI. But this method of treatment faces challenges such as: MSCs survival and paracrine secretion. MicroRNAs are post transcriptional regulatory molecules that regulate many biological processes including VEGF pathway. MicroRNAs could be used to increase viability and angiogenic potential of MSCs. This study was conducted to reinforce and increase the angiogenic potential of BM-MSCs by using microRNA-126 and evaluate the effect of this stem cell gene therapy on treatment of ischemic tissues in CLI mouse models. Methods: BM-MSCs were isolated from male C57 BL/6 inbred mice and characterized by morphology, flow cytometry, differentiation to osteocyte and adipocyte. Transformed BM-MSCs containing miR-126 were produced by using lentiviral vector. Then femoral artery ligation and total excision of the femoral artery was performed on C57BL/6 mice to create CLI model. Animals were allocated to control, BM-MSCs, virus and BM-MSCs miR-126 groups and defined number of the cells and virus were injected 24 h after surgery. In order to determine in vitro and in vivo effects, the following tests were performed: wound healing assay, behavioral tests including: Tarlov, Ischemia, Modified ischemia, Function and the grade of limb necrosis scores, donor cell survival assay, real-time PCR and histological analysis. Results: Results indicated that during 28 days after transplantation, BM-MSCs and virus groups had an enhancing effect on angiogenesis. BM-MSCs miR-126 group had remarkable effect on endothelial cell migration, muscle restructure, functional improvements and neovascularization in ischemic tissues and led to more effective treatment. In vivo evaluation showed that miR-126 could increase BM-MSCs survival and paracrine secretion of angiogenic factors such as VEGF, and led to remarkable functional improvements and neovascularization in ischemic tissues. Conclusions: According to the obtained results, it could concluded that combination of BM-MSCs and miR-126 leads to more effective recovery from critical limb ischemia compared to using them alone. In fact, miR-126 can be used as a strong modifier to reinforce the angiogenic potential of BM-MSCs, leading to more effective treatment for CLI.