Mesenchymal stem cell therapy improves diabetic cardiac autonomic neuropathy and decreases the inducibility of ventricular arrhythmias

Ginsenoside RG1-induced mesenchymal stem cells alleviate diabetic cardiomyopathy through secreting exosomal circNOTCH1 to promote macrophage M2 polarization

Diabetic cardiomyopathy (DCM) is a cardiac complication resulting from long-term uncontrolled diabetes, characterized by myocardial fibrosis and abnormal cardiac function. This study aimed at investigating the potential of ginsenoside RG1 (RG1)-induced mesenchymal stem cells (MSCs) in alleviating DCM. A DCM mouse model was constructed, and the effects of RG1-induced MSCs on myocardial function and fibrosis in diabetic mice were evaluated. RG1-induced MSCs were cocultured with high glucose-treated fibroblasts for subsequent functional and mechanism assays. It was discovered that RG1-induced MSCs secrete exosomes that induce macrophage M2 polarization. Mechanistically, exosomes derived from RG1-induced MSCs transferred circNOTCH1 into macrophages, activating the NOTCH signaling pathway. A competing endogenous RNA (ceRNA) regulatory axis consisting of circNOTCH1, miR-495-3p, and NOTCH1 was found to contribute to DCM alleviation.. This study unveiled that exosomal circNOTCH1 secreted by RG1-induced MSCs can alleviate DCM by activating the NOTCH signaling pathway to induce macrophage M2 polarization. This finding may contribute to the development of new therapeutic approaches for DCM.

Therapeutic Potential of Mesenchymal Stem Cell‐Derived Conditioned Medium for Diabetes Mellitus and Related Complications

Diabetes mellitus (DM) is one of the most life‐threatening metabolic disorders, with 9% of the global prevalence, and it is estimated to be rising to 12.2% in 2045. Currently, there is no definitive treatment for DM. Although life‐saving, insulin administration to control blood sugar is not a cure for DM and is insufficient to prevent DM‐related complications such as nephropathy, neuropathy, or retinopathy. For this reason, studies are continuing to develop treatments that will provide β‐cell regeneration while suppressing autoimmunity. Mesenchymal stem cells (MSCs) are multipotent stem cells with a high proliferation capacity, immunosuppression, and immunomodulation ability. MSCs have gained therapeutic importance with these properties besides their differentiation ability. The immunosuppressive and immunomodulatory properties of the cells arise from the soluble and insoluble factors they secrete into the extracellular environment. Therefore, the culture medium where these cells grow has therapeutic value and is named conditioned medium (CM). In this context, CM obtained from MSCs can provide a similar therapeutic effect with fewer safety concerns. Furthermore, preconditioning of MSCs can improve the effectiveness of these cells and associated cellular products. So, this review summarizes the recent advances in MSC‐derived CMs and their therapeutic potential for DM and related complications.

Effects of fastigial nucleus electrostimulation on cardiac nerve regeneration, neurotransmitter release, and malignant arrhythmia inducibility in a post-infarction rat model

The reduced density of cardiac autonomic nerves plays an important role in malignant arrhythmia after myocardial infarction (MI). Previous studies have shown that there is an interaction between the brain and the heart, and fastigial nucleus electrostimulation (FNS) promotes central nerve regeneration. Whether and how it can promote cardiac nerve regeneration after MI and the underlying mechanisms remain unknown. This study investigated whether FNS promotes cardiac nerve regeneration and reduces malignant arrhythmia inducibility in a post-infarction rat model. Ninety-eight Wistar rats were randomly assigned to Sham control, MI (left anterior descending coronary artery ligation without FNS), FNS (MI plus FNS), and FNL (fastigial nucleus lesion plus FNS plus MI) groups. The frequency of malignant arrhythmia was significantly lower in the FNS group than in the MI and FNL groups. The density of cardiac autonomic nerves was less in the MI group than in the Sham group, which was promoted by FNS. The nerve growth factor (NGF) mRNA expression was downregulated in the MI group compared to the Sham group, which was significantly enhanced by FNS. The expression levels of norepinephrine (NE) and acetylcholine (ACh) were higher and lower respectively in the MI and FNL groups than in the Sham group. After FNS, NE concentration was reduced and Ach level was elevated compared to the MI group. These data suggested that FNS promoted the regeneration of cardiac autonomic nerves and reduced the incidence of malignant arrhythmias in MI rat model. The mechanisms might involve up-regulation of NGF mRNA expression, decrease of NE release and increase of ACh release.

MSCs ameliorates DPN induced cellular pathology via [Ca2+ ]i homeostasis and scavenging the pro-inflammatory cytokines

The MSCs of various origins are known to ameliorate or modulate cell survival strategies. We investigated, whether UCB MSCs could improve the survival of the human neuronal cells and/or fibroblast assaulted with DPN sera. The results showed, the co-culture of UCB MSCs with human neuronal cells and/or fibroblasts could effectively scavenge the pro-inflammatory cytokines TNF-α, IL-1β, IFN-ɤ and IL - 12 and control the pro-apoptotic expression of p53/Bax. Further co-culture of UCB MSCs have shown to induce anti-inflammatory cytokines like IL-4, IL-10 and TGF-β and anti-apoptotic Bclxl/Bcl2 expression in the DPN sera stressed cells. Amelioration of elevated [Ca2+ ]i and cROS, the portent behind the NFκB/Caspase-3 mediated inflammation in DPN rescued the cells from apoptosis. The results of systemic administration of BM MSCs improved DPN pathology in rat as extrapolated from human cell model. The BM MSCs ameliorated prolonged distal motor latency (control: 0.70 ± 0.06, DPN: 1.29 ± 0.13 m/s DPN + BM MSCs: 0.89 ± 0.02 m/s, p < 0.05) and lowered high amplitude of compound muscle action potentials (CMAPs) (control: 12.36 ± 0.41, DPN: 7.52 ± 0.61 mV, DPN + MSCs: 8.79 ± 0.53 mV, p < 0.05), while slowly restoring the plasma glucose levels. Together, all these results showed that administration of BM or UCB MSCs improved the DPN via ameliorating pro-inflammatory cytokine signaling and [Ca2+ ]i homeostasis.

P2X7 receptor inhibition attenuated sympathetic nerve sprouting after myocardial infarction via the NLRP3/IL-1β pathway

Mounting evidence supports the hypothesis that inflammation modulates sympathetic sprouting after myocardial infarction (MI). The myeloid P2X₇ signal has been shown to activate the nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a master regulator of inflammation. We investigated whether P2X₇ signal participated in the pathogenesis of sympathetic reinnervation after MI, and whether NLRP3/interleukin-1β (IL-1β) axis is involved in the process. We explored the relationship between P2X₇ receptor (P2X₇ R) and IL-1β in the heart tissue of lipopolysaccharide (LPS)-primed naive rats. 3'-O-(4-benzoyl) benzoyl adenosine 5'-triphosphate (BzATP), a P2X₇ R agonist, induced caspase-1 activation and mature IL-1β release, which was further neutralized by a NLRP3 inhibitor (16673-34-0). MI was induced by coronary artery ligation. Following infarction, a marked increase in P2X₇ R was localized within infiltrated macrophages and observed in parallel with an up-regulation of NLRP3 inflammasome levels and the release of IL-1β in the left ventricle. The administration of A-740003 (a P2X₇ R antagonist) significantly prevented the NLRP3/IL-1β increase. A-740003 and/or Anakinra (an IL-1 receptor antagonist) significantly reduced macrophage infiltration as well as macrophage-based IL-1β and NGF (nerve growth factor) production and eventually blunted sympathetic hyperinnervation, as assessed by the immunofluorescence of tyrosine hydroxylase (TH) and growth-associated protein 43 (GAP 43). Moreover, the use of Anakinra partly attenuated sympathetic sprouting. This indicated that the effect of P2X₇ on neural remodelling was mediated at least partially by IL-1β. The arrhythmia score of programmed electric stimulation was in accordance with the degree of sympathetic hyperinnervation. In vitro studies showed that BzATP up-regulated secretion of nerve growth factor (NGF) in M1 macrophages via IL-1β. Together, these data indicate that P2X₇ R contributes to neural and cardiac remodelling, at least partly mediated by NLRP3/IL-1β axis. Therapeutic interventions targeting P2X₇ signal may be a novel approach to ameliorate arrhythmia following MI.

Long term effect and safety of Wharton's jelly-derived mesenchymal stem cells on type 2 diabetes

Cellular therapies offer novel opportunities for the treatment of type 2 diabetes mellitus (T2DM). The present study evaluated the long-term efficacy and safety of infusion of Wharton's jelly-derived mesenchymal stem cells (WJ-MSC) on T2DM. A total of 61 patients with T2DM were randomly divided into two groups on the basis of basal therapy; patients in group I were administered WJ-MSC intravenous infusion twice, with a four-week interval, and patients in group II were treated with normal saline as control. During the 36-month follow-up period, the occurrence of any adverse effects and the results of clinical and laboratory examinations were recorded and evaluated. The lack of acute or chronic adverse effects in group I was consistent with group II.. Blood glucose, glycosylated hemoglobin, C-peptide, homeostasis model assessment of pancreatic islet β-cell function and incidence of diabetic complications in group I were significantly improved, as compared with group II during the 36-month follow-up. The results of the present study demonstrated that infusion of WJ-MSC improved the function of islet β-cells and reduced the incidence of diabetic complications, although the precise mechanisms are yet to be elucidated. The infusion of WJ-MSC may be an effective option for the treatment of patients with type 2 diabetes.

Mesenchymal stem cells to treat diabetic neuropathy: a long and strenuous way from bench to the clinic

As one of the most common complications of diabetes, diabetic neuropathy often causes foot ulcers and even limb amputations. Inspite of continuous development in antidiabetic drugs, there is still no efficient therapy to cure diabetic neuropathy. Diabetic neuropathy shows declined vascularity in peripheral nerves and lack of angiogenic and neurotrophic factors. Mesenchymal stem cells (MSCs) have been indicated as a novel emerging regenerative therapy for diabetic neuropathy because of their multipotency. We will briefly review the pathogenesis of diabetic neuropathy, characteristic of MSCs, effects of MSC therapies for diabetic neuropathy and its related mechanisms. In order to treat diabetic neuropathy, neurotrophic or angiogenic factors in the form of protein or gene therapy are delivered to diabetic neuropathy, but therapeutic efficiencies are very modest if not ineffective. MSC treatment reverses manifestations of diabetic neuropathy. MSCs have an important role to repair tissue and to lower blood glucose level. MSCs even paracrinely secrete neurotrophic factors, angiogenic factors, cytokines, and immunomodulatory substances to ameliorate diabetic neuropathy. There are still several challenges in the clinical translation of MSC therapy, such as safety, optimal dose of administration, optimal mode of cell delivery, issues of MSC heterogeneity, clinically meaningful engraftment, autologous or allogeneic approach, challenges with cell manufacture, and further mechanisms.

Mesenchymal stem cells suppress cardiac alternans by activation of PI3K mediated nitroso-redox pathway

BACKGROUND

The paracrine action of non-cardiac progenitor cells is robust, but not well understood. Mesenchymal stem cells (MSC) have been shown to enhance calcium (Ca(++)) cycling in myocytes. Therefore, we hypothesized that MSCs can suppress cardiac alternans, an important arrhythmia substrate, by paracrine action on Ca(++) cycling.

METHODS AND RESULTS

Human cardiac myocyte monolayers derived from iPS cells (hCM) were cultured without or with human MSCs (hMSC) directly or plated on a transwell insert. Ca(++) transient alternans (Ca(++) ALT) and Ca(++) transient duration (CaD) were measured from hCM monolayers following application of 200μM H2O2. Ca(++) ALT in hCM was significantly decreased when cultured with hMSCs directly (97%, p<0.0001) and when cultured with hMSC in the transwell insert (80%, p<0.0001). When hCM with hMSCs were pretreated with PI3K or eNOS inhibitors, Ca(++) ALT was larger than baseline by 20% (p<0.0001) and 36% (p<0.0001), respectively. In contrast, Ca(++) ALT was reduced by 89% compared to baseline (p<0.0001) when hCM monolayers without hMSCs were pretreated with 20μM GSNO. In all experiments, changes in Ca(++) ALT were mirrored by changes in CaD. Finally, real time quantitative PCR revealed no significant differences in mRNA expression of RyR2, SERCA2a, and phospholamban between hCM cultured with or without hMSCs.

CONCLUSION

Ca(++) ALT is suppressed by hMSCs in a paracrine fashion due to activation of a PI3K-mediated nitroso-redox pathway. These findings demonstrate, for the first time, how stem cell therapy might be antiarrhythmic by suppressing cardiac alternans through paracrine action on Ca(++) cycling.

Beneficial effects of urine-derived stem cells on fibrosis and apoptosis of myocardial, glomerular and bladder cells

Urine-derived stem cells (USCs) are isolated from voided urine and display high proliferative activity and multiple differentiation potentials. The applicability of USCs in the treatment of bladder dysfunction and in cell-based urological tissue engineering has been demonstrated. Whether they could serve as a potential stem cell source for the treatment of diabetes mellitus (DM) and its complications has not been investigated. Here, we report the repairing and protective effects of USCs on pancreatic islets, the myocardium, the renal glomerulus and the bladder detrusor in diabetic rat models. Type 2 diabetic rat models were induced by means of a high fat diet and intraperitoneal injection with streptozotocin. USCs isolated from voided urine were administered via tail veins. The functional changes of pancreatic islets, left ventricle, glomerulus and bladder micturition were assessed by means of insulin tolerance tests, echocardiography, urine biochemical indexes and cystometry. The histologic changes were evaluated by hematoxylin and eosin staining, Masson's trichrome staining and TUNEL staining. Treatment with USCs significantly alleviated the histological destruction and functional decline. Although the USC treatment did not decrease fasting blood glucose to a significantly different level, the fibrosis and apoptosis of the myocardium, glomerulus and detrusor were significantly inhibited. This study indicates that administration of USCs may be useful for the treatment of the complications of DM.

Antiarrhythmic effect of growth factor-supplemented cardiac progenitor cells in chronic infarcted heart

c-Kit(pos) cardiac progenitor cells (CPCs) represent a successful approach in healing the infarcted heart and rescuing its mechanical function, but electrophysiological consequences are uncertain. CPC mobilization promoted by hepatocyte growth factor (HGF) and IGF-1 improved electrogenesis in myocardial infarction (MI). We hypothesized that locally delivered CPCs supplemented with HGF + IGF-1 (GFs) can concur in ameliorating electrical stability of the regenerated heart. Adult male Wistar rats (139 rats) with 4-wk-old MI or sham conditions were randomized to receive intramyocardial injection of GFs, CPCs, CPCs + GFs, or vehicle (V). Enhanced green fluorescent protein-tagged CPCs were used for cell tracking. Vulnerability to stress-induced arrhythmia was assessed by telemetry-ECG. Basic cardiac electrophysiological properties were examined by epicardial multiple-lead recording. Hemodynamic function was measured invasively. Hearts were subjected to anatomical, morphometric, immunohistochemical, and molecular biology analyses. Compared with V and at variance with individual CPCs, CPCs + GFs approximately halved arrhythmias in all animals, restoring cardiac anisotropy toward sham values. GFs alone reduced arrhythmias by less than CPCs + GFs, prolonging ventricular refractoriness without affecting conduction velocity. Concomitantly, CPCs + GFs reactivated the expression levels of Connexin-43 and Connexin-40 as well as channel proteins of key depolarizing and repolarizing ion currents differently than sole GFs. Mechanical function and anatomical remodeling were equally improved by all regenerative treatments, thus exhibiting a divergent behavior relative to electrical aspects. Conclusively, we provided evidence of distinctive antiarrhythmic action of locally injected GF-supplemented CPCs, likely attributable to retrieval of Connexin-43, Connexin-40, and Cav1.2 expression, favoring intercellular coupling and spread of excitation in mended heart.

Mesenchymal Stem Cells Improve Heart Rate Variability and Baroreflex Sensitivity in Rats with Chronic Heart Failure

Heart failure induced by myocardial infarct (MI) attenuates the heart rate variability (HRV) and baroreflex sensitivity, which are important risk factors for life-threatening cardiovascular events. Therapies with mesenchymal stem cells (MSCs) have shown promising results after MI. However, the effects of MSCs on hemodynamic (heart rate and arterial pressure) variability and baroreflex sensitivity in chronic heart failure (CHF) following MI have not been evaluated thus far. Male Wistar rats received MSCs or saline solution intravenously 1 week after ligation of the left coronary artery. Control (noninfarcted) rats were also evaluated. MI size was assessed using single-photon emission computed tomography (SPECT). The left ventricular ejection fraction (LVEF) was evaluated using radionuclide ventriculography. Four weeks after MSC injection, the animals were anesthetized and instrumented for chronic ECG recording and catheters were implanted in the femoral artery to record arterial pressure. Arterial pressure and HRVs were determined in time and frequency domain (spectral analysis) while HRV was also examined using nonlinear methods: DFA (detrended fluctuation analysis) and sample entropy. The initial MI size was the same among all infarcted rats but was reduced by MSCs. CHF rats exhibited increased myocardial interstitial collagen and sample entropy combined with the attenuation of the following cardiocirculatory parameters: DFA indices, LVEF, baroreflex sensitivity, and HRV. Nevertheless, MSCs hampered all these alterations, except the LVEF reduction. Therefore, 4 weeks after MSC therapy was applied to CHF rats, MI size and myocardial interstitial fibrosis decreased, while baroreflex sensitivity and HRV improved.

In rats the duration of diabetes influences its impact on cardiac autonomic innervations and electrophysiology

Diabetic cardiac autonomic neuropathy (DCAN) may cause fatal ventricular arrhythmias and increase mortality in diabetics. However, limited data are available with regard to the precise changes in cardiac autonomic denervation after diabetes onset. In this study, we dynamically observed the progression of DCAN and its relationship with the inducibility of ventricular arrhythmias in diabetic rats. Rats were randomly divided into normal control and diabetes mellitus (DM) groups. The rats were sacrificed at 3 or 6 months post-treatment. Heart rate variability and programmed electrical stimulation were used to assess the electrophysiological characteristics and the inducibility of ventricular arrhythmias in the animals. Immunohistochemistry and real-time RT-PCR were used to measure choline acetyltransferase and tyrosine hydroxylase-positive nerve fibers and the corresponding mRNA expression levels in the proximal and distal regions of the left ventricle. Short-term diabetes resulted in distal myocardial parasympathetic denervation with sparing of the proximal myocardium. By 6 months, both parasympathetic and sympathetic denervation were further aggravated. Moreover, electrophysiological experiments demonstrated a sympatho-parasympathetic imbalance and an increase in ventricular arrhythmia inducibility in the diabetic rats. These results suggest that DM causes cardiac nerve denervation, relative sympathetic hyperinnervation and inhomogeneous neural innervations, which may be associated with an increase in the induction of ventricular arrhythmia in diabetic rats.

Cardiac regeneration and diabetes

The prevalence of diabetes continues to increase world-wide and is a leading cause of morbidity, mortality, and rapidly rising health care costs. Although strict glucose control combined with good pharmacological and non-pharmacologic interventions can increase diabetic patient life span, the frequency and mortality of myocardial ischemia and infarction remain drastically increased in diabetic patients. Therefore, more effective therapeutic approaches are urgently needed. Over the past 15 years, cellular repair of the injured adult heart has become the focus of a rapidly expanding broad spectrum of pre-clinical and clinical research. Recent clinical trials have achieved favorable initial endpoints with improvements in cardiac function and clinical symptoms following cellular therapy. Due to the increased risk of cardiac disease, cardiac regeneration may be one strategy to treat patients with diabetic cardiomyopathy and/or myocardial infarction. However, pre-clinical studies suggest that the diabetic myocardium may not be a favorable environment for the transplantation and survival of stem cells due to altered kinetics in cellular homing, survival, and in situ remodeling. Therefore, unique conditions in the diabetic myocardium will require novel solutions in order to increase the efficiency of cellular repair following ischemia and/or infarction. This review briefly summarizes some of the recent advances in cardiac regeneration in non-diabetic conditions and then provides an overview of some of the issues related to diabetes that must be addressed in the coming years.

The potential of cell-based therapy for diabetes and diabetes-related vascular complications

Cell therapy has enormous potential for the treatment of conditions of unmet medical need. Cell therapy may be applied to diabetes mellitus in the context of beta cell replacement or for the treatment of diabetic complications. A large number of cell types including hematopoietic stem cells, mesenchymal stem cells, umbilical cord blood, conditioned lymphocytes, mononuclear cells, or a combination of these cells have been shown to be safe and feasible for the treatment of patients with diabetes mellitus. The first part of this review article will focus on the current perspective of the role of embryonic stem cells and inducible pluripotent stem cells for beta cell replacement and the current clinical data on cell-based therapy for the restoration of normoglycemia. The second part of this review will highlight the therapeutic role of MSCs in islet cells cotransplantation and the management of diabetes related vascular complications.

Mesenchymal stem cell-based treatment for microvascular and secondary complications of diabetes mellitus

The worldwide increase in the prevalence of Diabetes mellitus (DM) has highlighted the need for increased research efforts into treatment options for both the disease itself and its associated complications. In recent years, mesenchymal stromal cells (MSCs) have been highlighted as a new emerging regenerative therapy due to their multipotency but also due to their paracrine secretion of angiogenic factors, cytokines, and immunomodulatory substances. This review focuses on the potential use of MSCs as a regenerative medicine in microvascular and secondary complications of DM and will discuss the challenges and future prospects of MSCs as a regenerative therapy in this field. MSCs are believed to have an important role in tissue repair. Evidence in recent years has demonstrated that MSCs have potent immunomodulatory functions resulting in active suppression of various components of the host immune response. MSCs may also have glucose lowering properties providing another attractive and unique feature of this therapeutic approach. Through a combination of the above characteristics, MSCs have been shown to exert beneficial effects in pre-clinical models of diabetic complications prompting initial clinical studies in diabetic wound healing and nephropathy. Challenges that remain in the clinical translation of MSC therapy include issues of MSC heterogeneity, optimal mode of cell delivery, homing of these cells to tissues of interest with high efficiency, clinically meaningful engraftment, and challenges with cell manufacture. An issue of added importance is whether an autologous or allogeneic approach will be used. In summary, MSC administration has significant potential in the treatment of diabetic microvascular and secondary complications but challenges remain in terms of engraftment, persistence, tissue targeting, and cell manufacture.