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    Mesenchymal stem cell-derived exosomes improve diabetes mellitus-induced myocardial injury and fibrosis via inhibition of TGF-β1/Smad2 signaling pathway. Lin Yuan,Zhang Fang,Lian Xiao-Fen,Peng Wei-Qun,Yin Chao-Yao Cellular and molecular biology (Noisy-le-Grand, France) The aim of this study is to investigate  the effect of mesenchymal stem cell (MSC)-derived exosomes on diabetes mellitus-induced myocardial injury, and the underlying mechanism. Thirty adult male Sprague Dawley rats were randomly assigned to three groups of ten rats each: normal control group, diabetic control group and MSC exosomes group. Exosomes were isolated from MSCs through gradient ultracentrifugation. With the exception of normal control, diabetes mellitus (DM) was induced in the rats with a single intraperitoneal injection of 30 mg/kg body weight streptozotocin (STZ) in 0.1 mol/L sodium citrate buffer. Rats in MSC exosomes group were intravenously injected with MSC-derived exosomes once a week for 12 weeks. Left ventricular collagen (LVC) level was measured using acid hydrolysis method. Fatty acid transporters (FATPs) and fatty acid beta oxidase (FA-β-oxidase) were determined using enzyme-linked immunosorbent assay (ELISA). Gene and protein expressions of TGF-β and Smad2 were determined using real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting. Flow cytometric analysis and Western blotting revealed positive expression of exosomal specific marker, CD63. The level of LVC was significantly higher in diabetic control group than in normal control group, but was significantly reduced after treatment with MSC-derived exosomes (p < 0.05). The levels of FATPs and FA-β-oxidase were significantly lower in diabetic control group than in normal control group (p < 0.05). However, treatment with MSC-derived exosomes significantly increased the levels of these proteins (p < 0.05). The levels of expression of TGF-β1 and Smad2 mRNAs were significantly higher in the diabetic control group than in normal control group, but were significantly reduced after treatment with MSC-derived exosomes (p < 0.05). The expressions of TGF-β1 and Smad2 proteins were also significantly upregulated in diabetic control group, when compared with normal control group (p < 0.05). However, treatment with MSC-derived exosomes significantly down-regulated the expression of these proteins (p < 0.05). The results obtained in this study indicate that MSC-derived exosomes improve DM-induced myocardial injury and fibrosis via inhibition of TGF-β1/Smad2 signaling pathway.
    Mechanistic insights into the augmented effect of bone marrow mesenchymal stem cells and thiazolidinediones in streptozotocin-nicotinamide induced diabetic rats. Hamza Alaaeldin Ahmed,Fikry Ebtehal Mohammad,Abdallah Wedad,Amin Amr Scientific reports This study was designed to assess whether the protective effects of bone marrow-derived mesenchymal stem cells (MSCs) against diabetes could be enhanced by pioglitazone (PIO), a PPARγ agonist. Combined MSCs and PIO treatments markedly improved fasting blood glucose, body weight, lipid profile levels, insulin level, insulin resistance, β cell function. Those protective effects also attenuated both pancreatic lesions and fibrosis in diabetic rats and decreased the depletion of pancreatic mediators of glycemic and lipid metabolism including peroxisome proliferator-activated receptor alpha (PPARα), PGC-1α, GLP-1 and IRS-2. Cardiac biogenesis of diabetic groups was also improved with MSCs and/or PIO treatments as reflected by the enhanced up-regulation of the expressions of cardiac IRS1, Glucose transporter 4, PGC-1, PPARα and CPT-1 genes and the down-regulated expression of lipogenic gene SREBP. The combination of MSCs and PIO also potentiated the decrease of abnormal myocardial pathological lesions in diabetic rats. Similarly, the inhibitory effects of MSCs on diabetic cardiac fibrosis and on the up regulations of TGF-β, collagen I and III gene expressions were partial but additive when combined with PIO. Therefore, combined therapy with PIO and BMCs transplantation could further potentiate the protective benefit of MSCs against diabetes and cardiac damage compared to MSCs monotherapy. 10.1038/s41598-018-28029-1
    Preconditioning diabetic mesenchymal stem cells with myogenic medium increases their ability to repair diabetic heart. Khan Mohsin,Ali Fatima,Mohsin Sadia,Akhtar Shoaib,Mehmood Azra,Choudhery Mahmood S,Khan Shaheen N,Riazuddin Sheikh Stem cell research & therapy INTRODUCTION:Mesenchymal stem cells (MSCs) have the potential for treatment of diabetic cardiomyopathy; however, the repair capability of MSCs declines with age and disease. MSCs from diabetic animals exhibit impaired survival, proliferation, and differentiation and therefore require a strategy to improve their function. The aim of the study was to develop a preconditioning strategy to augment the ability of MSCs from diabetes patients to repair the diabetic heart. METHODS:Diabetes was induced in C57BL/6 mice (6 to 8 weeks) with streptozotocin injections (55 mg/kg) for 5 consecutive days. MSCs isolated from diabetic animals were preconditioned with medium from cardiomyocytes exposed to oxidative stress and high glucose (HG/H-CCM). RESULTS:Gene expression of VEGF, ANG-1, GATA-4, NKx2.5 MEF2c, PCNA, and eNOS was upregulated after preconditioning with HG/H-CCM, as evidenced by reverse transcriptase/polymerase chain reaction (RT-PCR). Concurrently, increased AKT phosphorylation, proliferation, angiogenic ability, and reduced levels of apoptosis were observed in HG/H-CCM-preconditioned diabetic MSCs compared with nontreated controls. HG/H-CCM-preconditioned diabetic-mouse-derived MSCs (dmMSCs) were transplanted in diabetic animals and demonstrated increased homing concomitant with augmented heart function. Gene expression of angiogenic and cardiac markers was significantly upregulated in conjunction with paracrine factors (IGF-1, HGF, SDF-1, FGF-2) and, in addition, reduced fibrosis, apoptosis, and increased angiogenesis was observed in diabetic hearts 4 weeks after transplantation of preconditioned dmMSCs compared with hearts with nontreated diabetic MSCs. CONCLUSIONS:Preconditioning with HG/H-CCM enhances survival, proliferation, and the angiogenic ability of dmMSCs, augmenting their ability to improve function in a diabetic heart. 10.1186/scrt207
    Mesenchymal stem cells promote type 2 macrophage polarization to ameliorate the myocardial injury caused by diabetic cardiomyopathy. Jin Liyuan,Deng Zihui,Zhang Jinying,Yang Chen,Liu Jiejie,Han Weidong,Ye Ping,Si Yiling,Chen Guanghui Journal of translational medicine BACKGROUND:Diabetic cardiomyopathy (DCM) is a common complication of diabetes and is characterized by chronic myocardial inflammation. Mesenchymal stem cell (MSC) infusions have recently been suggested to alleviate myocardial injury and ameliorate cardiac function. However, few studies have focused on the effects of MSCs in DCM. Therefore, we explored the effects of MSC-regulated macrophage polarization on myocardial repair in DCM. METHODS:A DCM rat model was induced by a high-fat diet and streptozotocin (STZ) administration and infused 4 times with MSCs. Rat blood and heart tissue were analyzed for blood glucose levels, lipid levels, echocardiography, histopathology, macrophage phenotype ratios and inflammatory cytokines, respectively. We mimicked chronic inflammation in vitro by inducing peritoneal macrophages with high glucose and LPS, then cocultured these macrophages with MSCs to explore the specific mechanism of MSCs on macrophage polarization. RESULTS:DCM rats exhibited abnormal blood glucose levels and lipid metabolism, cardiac inflammation and dysfunction. MSC infusion ameliorated metabolic abnormalities and preserved cardiac structure and function in DCM rats. Moreover, MSC infusion significantly increased the M2 phenotype macrophages and alleviated cardiac inflammation. Interestingly, this in vitro study revealed that the MSCs pretreated with a COX-2 inhibitor had little effect on M2 macrophage polarization, but this phenomenon could be reversed by adding prostaglandin E2 (PGE2). CONCLUSIONS:Our results suggested that MSC infusions can protect against cardiac injury in DCM rats. The underlying mechanisms may include MSC-enhanced M2 macrophage polarization via the COX-2-PGE2 pathway. 10.1186/s12967-019-1999-8
    Mesenchymal stem cells ameliorate myocardial fibrosis in diabetic cardiomyopathy via the secretion of prostaglandin E2. Jin Liyuan,Zhang Jinying,Deng Zihui,Liu Jiejie,Han Weidong,Chen Guanghui,Si Yiling,Ye Ping Stem cell research & therapy BACKGROUND:Diabetic cardiomyopathy (DCM) is a cardiac complication of long-term uncontrolled diabetes and is characterized by myocardial fibrosis and abnormal cardiac function. Mesenchymal stem cells (MSCs) are multipotent cells with immunoregulatory and secretory functions in diabetes and heart diseases. However, very few studies have focused on the effect and the underlying mechanism of MSCs on myocardial fibrosis in DCM. Therefore, we aimed to explore the therapeutic potential of MSCs in myocardial fibrosis and its underlying mechanism in vivo and in vitro. METHODS:A DCM rat model was induced using a high-fat diet (HFD) combined with a low-dose streptozotocin (STZ) injection. After four infusions of MSCs, rat serum and heart tissues were collected, and the levels of blood glucose and lipid, cardiac structure, and function, and the degree of myocardial fibrosis including the expression levels of pro-fibrotic factor and collagen were analyzed using biochemical methods, echocardiography, histopathology, polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA). We infused prostaglandin E2 (PGE2)-deficient MSCs to DCM rats in vivo and established a system mimicking diabetic myocardial fibrosis in vitro by inducing cardiac fibroblasts with high glucose (HG) and coculturing them with MSCs or PGE2-deficient MSCs to further explore the underlying mechanism of amelioration of myocardial fibrosis by MSCs. RESULTS:Metabolic abnormalities, myocardial fibrosis, and cardiac dysfunction in DCM rats were significantly ameliorated after treatment with MSCs. Moreover, the levels of TGF-β, collagen I, collagen III, and collagen accumulation were markedly decreased after MSC infusion compared to those in DCM hearts. However, PGE2-deficient MSCs had decreased ability to alleviate cardiac fibrosis and dysfunction. In addition, in vitro study revealed that the concentration of PGE2 in the MSC group was enhanced, while the proliferation and collagen secretion of cardiac fibroblasts were reduced after MSC treatment. However, MSCs had little effect on alleviating fibrosis when the fibroblasts were pretreated with cyclooxygenase-2 (COX-2) inhibitors, which also inhibited PGE2 secretion. This phenomenon could be reversed by adding PGE2. CONCLUSIONS:Our results indicated that MSC infusion could ameliorate cardiac fibrosis and dysfunction in DCM rats. The underlying mechanisms might involve the function of PGE2 secreted by MSCs. 10.1186/s13287-020-01633-7