Association of metformin monotherapy or combined therapy with cardiovascular risks in patients with type 2 diabetes mellitus.

BACKGROUND: Metformin is a first-line drug in type 2 diabetes mellitus (T2DM) treatment, yet whether metformin may increase all-cause or cardiovascular mortality of T2DM patients remains inconclusive. METHODS: We searched PubMed and Embase for data extracted from inception to July 14, 2020, with a registration in PROSPERO (CRD42020177283). This study included randomized controlled trials (RCT) assessing the cardiovascular effects of metformin for T2DM. This study is followed by PRISMA and Cochrane guideline. Risk ratio (RR) with 95% CI was pooled across trials by a random-effects model. Primary outcomes include all-cause mortality and cardiovascular mortality. RESULTS: We identified 29 studies that randomly assigned patients with 371 all-cause and 227 cardiovascular death events. Compared with untreated T2DM patients, metformin-treated patients was not associated with lower risk of all-cause mortality (RR: 0.98; 95%CI: 0.69-1.38; P = 0.90), cardiovascular mortality (RR: 1.13; 95% CI: 0.60, 2.15; P = 0.70), macrovascular events (RR: 0.87; 95%CI: 0.70-1.07; P = 0.19), heart failure (RR: 1.02; 95% CI:0.61-1.71; P = 0.95), and microvascular events (RR: 0.78; 95% CI:0.54-1.13; P = 0.19). Combination of metformin with another hypoglycemic drug was associated with higher risk of all-cause mortality (RR: 1.49; 95% CI: 1.02, 2.16) and cardiovascular mortality (RR: 2.21; 95% CI: 1.22, 4.00) compared with hypoglycemic drug regimens with no metformin. CONCLUSION: The combination of metformin treatment may impose higher risk in all-cause and cardiovascular mortality. This finding, at least in part, shows no evidence for benefits of metformin in combination in terms of all-cause/cardiovascular mortality and cardiovascular events for T2DM. However, the conclusion shall be explained cautiously considering the limitations from UK Prospective Diabetes Study (UKPDS).

Derivation of novel naive-like porcine embryonic stem cells by a reprogramming factor-assisted strategy.

The establishment of ungulate embryonic stem cells (ESCs) has been notoriously difficult via a conventional approach. We combined a traditional ESC culture method with reprogramming factors to assist the establishment of porcine naive-like ESCs (nESCs). Pig embryonic fibroblasts were transfected with a tetracycline-inducible vector carrying 4 classic mouse reprogramming factors, followed by somatic cell nuclear transfer and culturing to the blastocyst stage. Then, the inner cell mass was isolated and seeded in culture medium. The naive-like ESCs had characteristic verys similar to those of mouse ESCs and showed no signs of altered morphology or differentiation, even after 130 passages. They depended on leukemia inhibitory factor signals for maintenance of pluripotency, and the female cell lines had low expression of the X-inactive specific transcript gene and no histone H3 lysine 27 trimethylation spot. Notably, the ESCs differentiated into 3 germ layers in vitro and could be induced to undergo directional neural and kidney precursor differentiation under defined conditions, and the ESCs could keep proliferating after doxycycline was removed. nESCs can be established, and the well-characterized ESC lines will be useful for the research of transgenic pig models for human disease.-Zhang, M., Wang, C., Jiang, H., Liu, M., Yang, N., Zhao, L., Hou, D., Jin, Y., Chen, Q., Chen, Y., Wang, J., Dai, Y., Li, R. Derivation of novel naive-like porcine embryonic stem cells by a reprogramming factor-assisted strategy.

Disabling of nephrogenesis in porcine embryos via CRISPR/Cas9-mediated SIX1 and SIX4 gene targeting.

SIX1 and SIX4 genes play critical roles in kidney development. We evaluated the effect of these genes on pig kidney development by generating SIX1-/- and SIX1-/- /SIX4-/- pig foetuses using CRISPR/Cas9 and somatic cell nuclear transfer. We obtained 3 SIX1-/- foetuses and 16 SIX1-/- /SIX4-/- foetuses at different developmental stages. The SIX1-/- foetuses showed a migration block of the left kidney and a smaller size for both kidneys. The ureteric bud failed to form the normal branching and collecting system. Abnormal expressions of kidney development-related genes (downregulation of PAX2, PAX8, and BMP4 and upregulation of EYA1 and SALL1) were also observed in SIX1-/- foetal kidneys and confirmed in vitro in porcine kidney epithelial cells (PK15) following SIX1 gene deletion. The SIX1-/- /SIX4-/- foetuses exhibited more severe phenotypes, with most foetuses showing retarded development at early stages of gestation. The kidney developed only to the initial stage of metanephros formation. These results demonstrated that SIX1 and SIX4 are key genes for porcine metanephros development. The creation of kidney-deficient porcine foetuses provides a platform for generating human kidneys inside pigs using blastocyst complementation.

Melatonin attenuates chronic pain related myocardial ischemic susceptibility through inhibiting RIP3-MLKL/CaMKII dependent necroptosis.

Chronic pain aggravates cardiovascular injury via incompletely understood mechanisms. While melatonin may participate in the pathophysiological process of chronic pain, its cardiovascular effects under chronic pain states remains unknown. In this study, chronic pain was induced by spared nerve injury model (SNI) for 4 weeks. We showed decreased the ipsilateral hind paw withdrawal mechanical threshold (PWMT) in SNI mice. High dose melatonin treatment (60 mg/kg, i.p.) could reversed nociceptive threshold in SNI mice. To verify the effect of chronic pain on the cardiac tolerance to ischemic stress, mice were subjected to myocardial ischemia-reperfusion (MI/R) in vivo. SNI mice showed exaggerated MI/R-induced detrimental effects and myocardial necroptosis compared with control group (P < .05). Mechanically, an increased level of tumor necrosis factor-α (TNF-α) was found in SNI group following by a robust interaction of RIP1/RIP3. RIP3-induced phosphor-MLKL and CaMKII more significantly in SNI mice (P < .05). We found that RIP3 deficiency provided a comparable protection against MI/R-induced necroptosis under chronic pain conditions. More importantly, low dose melatonin (20 mg/kg, i.p.) treatment 10 min before reperfusion decreased the level of TNF-α following with a negatively regulating the RIP3 induced phosphor-MLKL/CaMKII signaling, thus significantly reduced ROS production and cardiomyocyte necroptosis and ameliorated cardiac function. In summarize, our results demonstrated that chronic pain sensitizes heart to MI/R injury and myocardial necrosis plays an important role in this pathophysiological process. We also define melatonin acted as triple cardioprotective effects: ameliorating TNF-α level, suppressing RIP3-MLKL/CaMKII signaling induced necroptosis and exerting analgesia effect.

Automatic regulation of NF-κB by pHSP70/IκBαm to prevent acute lung injury in mice.

Controlling target gene expression is a vital step in the procedure of gene therapy upon acute lung injury (ALI). Excessive activation of nuclear factor-kappa B (NF-κB) has been the key point of the inflammation overwhelming process in onset of ALI. We designed and tested a variety of plasmid named pHSP70/IκBαm which conditionally carries a mutant inhibitor of kappa B (IκB) transgene to regulate the activity of NF-κB signaling pathway in its response to an inflammatory stimulus that causes acute lung injury. Results recorded along our experiments showed that pHSP70/IκBαm was able to control mutant IκB expression in RAW264.7 cells with reference to the level of inflammatory response induced by LPS, thereby inhibiting NF-κB activation and downstream inflammatory cytokine expression. Vivo experiments revealed that construction naming pHSP70/IκBαm reduced LPS-induced lung injury and the secretion of inflammatory factors from lungs, hearts, and livers of sample mice in a LPS dose-dependent manner. In conclusion, the promoter heat shocking protein 70(HSP70) regulatory sequence of the construction was shown to drive mutant IκB expression so that its levels were positively associated with the dose of LPS used to induce acute lung injury. NF-κB activation and the downstream expression of inflammatory factors were therefore down-regulated in along an efficient path and ameliorating the damage as a consequence of LPS-induced acute lung injury.

Resveratrol alleviate hypoxic pulmonary hypertension via anti-inflammation and anti-oxidant pathways in rats.

Resveratrol, a plant-derived polyphenolic compound and a phytoestrogen, was shown to possess multiple protective effects including anti-inflammatory response and anti-oxidative stress. Hypoxic pulmonary hypertension (HPH) is a progressive disease characterized by sustained vascular resistance and marked pulmonary vascular remodeling. The exact mechanisms of HPH are still unclear, but inflammatory response and oxidative stress was demonstrated to participate in the progression of HPH. The present study was designed to investigate the effects of resveratrol on HPH development. Sprague-Dawley rats were challenged by hypoxia exposure for 28 days to mimic hypoxic pulmonary hypertension along with treating resveratrol (40 mg/kg/day). Hemodynamic and pulmonary pathomorphology data were then obtained, and the anti-proliferation effect of resveratrol was determined by in vitro assays. The anti-inflammation and anti-oxidative effects of resveratrol were investigated in vivo and in vitro. The present study showed that resveratrol treatment alleviated right ventricular systolic pressure and pulmonary arterial remodeling induced by hypoxia. In vitro experiments showed that resveratrol notably inhibited proliferation of pulmonary arterial smooth muscle cells in an ER-independent manner. Data showed that resveratrol administration inhibited HIF-1 α expression in vivo and in vitro, suppressed inflammatory cells infiltration around the pulmonary arteries, and decreased ROS production induced by hypoxia in PAMSCs. The inflammatory cytokines' mRNA levels of tumor necrosis factor α, interleukin 6, and interleukin 1ß were all suppressed by resveratrol treatment. The in vitro assays showed that resveratrol inhibited the expression of HIF-1 α via suppressing the MAPK/ERK1 and PI3K/AKT pathways. The antioxidant axis of Nuclear factor erythroid-2 related factor 2/ Thioredoxin 1 (Nrf-2/Trx-1) was up-regulated both in lung tissues and in cultured PASMCs. In general, the current study demonstrated that resveratrol may prevent pulmonary hypertension through its anti-proliferation, anti-inflammation and antioxidant effects. Hence, the present data may offer novel targets and promising pharmacological perspective for treating hypoxic pulmonary hypertension.

Tanshinone IIA attenuates bleomycin-induced pulmonary fibrosis via modulating angiotensin-converting enzyme 2/ angiotensin-(1-7) axis in rats.

Pulmonary fibrosis (PF) is a common complication in those interstitial lung diseases patients, which will result in poor prognosis and short survival. Traditional therapeutic methods such as glucocorticoid and cytotoxic drugs are insufficient for treating PF and may cause severe side effects. Recent studies showed that traditional Chinese herbal abstraction such as Tanshinone IIA (TIIA) was displayed significant anti-PF effects in animal models. However, the exact mechanisms underlying the protective effects of TIIA were not fully understood. Here we further investigated the protective effects of TIIA and its mechanisms underlying. PF models of rat were induced by bleomycin (BLM); TIIA was administered subsequently. The PF changes were identified by histopathological analyses. The results showed that BLM resulted in severe PF and alveolar inflammation; together with significant elevation of transforming growth factor-ß 1 (TGF-ß1). Angiotensin-converting enzyme 2 (ACE-2) together with angiotensin-(1-7) [ANG-(1-7)] were both greatly reduced after BLM administration. TIIA treatment notably attenuated BLM induced PF and inflammation, decreased expression of TGF-ß1 and reversed ACE-2 and ANG-(1-7) production in rat lungs. Thus we may draw the conclusion that TIIA may exert protective effects on BLM induced PF in rats, and the ACE-2/ANG-(1-7) axis may ascribe to those protective effects.

Acacetin protects against acute lung injury by upregulating SIRT1/ NF-κB pathway.

Acacetin is one of the natural flavone components found in many plants and possesses diverse pharmacological activities. The anti-inflammatory properties and definite mechanism of acacetin remains incompletely illuminated. Here, we evaluated the efficacy of acacetin on lipopolysaccharide (LPS)-induced acute lung injury in vivo and TNF-α-stimulated cellular injury in vitro. As indicated by survival experiments, acacetin reduced mortality and improved survival time of LPS-induced acute lung injury in mice. 50 mg/kg of acacetin obtained higher survival (about 60 %), and 20 mg/kg of acacetin was about 46.7 %. In addition, 20 mg/kg of acacetin rescued lung histopathologic damage in LPS treated mice, lowered lung-to-body weight and lung wet-to-dry ratios, suppressed myeloperoxidase activity in lung tissue, the contents of protein, the numbers of total cells and neutrophils in bronchoalveolar lavage fluid (BALF), and the contents of inflammatory cytokines such as TNF-α, IL-6, IL-17 and IL-1ß in BALF. Acacetin also increased the activity and expression of SIRT1, thereby suppressing acetylation-dependent activation NF-κB. Similarly, in vitro, acacetin increased cell viability, reduced levels of TNF-α, IL-6, IL-17, and IL-1ß, increased NAD+ levels as well as NAD/NADH ratio, and then up-regulated the activity and expression of SIRT1, and restrained acetylation-dependent activation NF-κB in TNF-α-stimulated A549 cells, which could be abolished by SIRT1 siRNA. Collectively, the current study showed that acacetin exerts a protective effiect on acute lung injury by improving the activity and expression SIRT1, thereby suppressing the acetylation-dependent activation of NF-κB-p65 and the release of downstream inflammatory cytokines.

Post-translational modifications of pyruvate dehydrogenase complex in cardiovascular disease.

Pyruvate dehydrogenase complex (PDC) is a crucial enzyme that connects glycolysis and the tricarboxylic acid (TCA) cycle pathway. It plays an essential role in regulating glucose metabolism for energy production by catalyzing the oxidative decarboxylation of pyruvate to acetyl coenzyme A. Importantly, the activity of PDC is regulated through post-translational modifications (PTMs), phosphorylation, acetylation, and O-GlcNAcylation. These PTMs have significant effects on PDC activity under both physiological and pathophysiological conditions, making them potential targets for metabolism-related diseases. This review specifically focuses on the PTMs of PDC in cardiovascular diseases (CVDs) such as myocardial ischemia/reperfusion injury, diabetic cardiomyopathy, obesity-related cardiomyopathy, heart failure (HF), and vascular diseases. The findings from this review offer theoretical references for the diagnosis, treatment, and prognosis of CVD.

Leptin attenuates lipopolysaccharide or oleic acid-induced acute lung injury in mice.

Leptin is reported to be involved in acute lung injury (ALI). However, the role and underlying mechanisms of leptin in ALI remain unclear. The aim of this study was to determine whether leptin deficiency promoted the development of ALI. LPS or oleic acid (OA) were administered to wild-type and leptin deficient (ob/ob) mice to induce ALI. Leptin level, survival rate, and lung injury were examined. Results showed that leptin levels were predominantly increased in the lung, but also in the heart, liver, kidney, and adipose tissue after LPS adminiatration. Compared with wild-type mice, LPS- or OA-induced lung injury was worse and the survival rate was lower in ob/ob mice. Moreover, leptin deficiency promoted the release of proinflammatory cytokines. Exogenous administration of leptin reduced lethality in ob/ob mice and ameliorated lung injury partly through inhibiting the activation of NF-κB, p38, and ERK pathways. These results indicated that leptin deficiency contributed to the development of lung injury by enhancing inflammatory response, and a high level of leptin improved survival and protected against ALI.

Endogenous estrogen attenuates hypoxia-induced pulmonary hypertension by inhibiting pulmonary arterial vasoconstriction and pulmonary arterial smooth muscle cells proliferation.

Exogenous estrogen was shown to exert various beneficial effects on multiple diseases including hypoxia-induced pulmonary hypertension (HPH). However, the effect of endogenous estrogen on HPH was seldom investigated. In the present study, we explored the protective effects and mechanisms of endogenous estrogen on hypoxia-induced pulmonary hypertension. Male, female, pregnant and ovariectomized rats were housed in a hypoxic condition for 21 days, and then hemodynamic together with morphologic indexes of pulmonary circulation were measured. The right ventricular systolic pressure, mean pulmonary artery pressure, right ventricular hypertrophy index, and arterial remodeling index were significantly elevated after chronic hypoxia exposure. Experimental data showed less severity in female, especially in pregnant rats. In vitro, artery rings of different sex or estrus cycle rats were obtained, and then artery rings experiments were performed to investigate pulmonary vasoconstriction by recording the maximum phase II vasoconstriction. Data showed that the vasoconstriction was milder in proestrus female than diestrus female or male groups, which could be leveled by treating U0126 (a MAPK pathway inhibitor). Pulmonary arterial smooth muscle cells isolated from different sex or estrus cycle rats were cultured in the condition of 2% oxygen for 24 hours, and cell proliferation was evaluated by the [3H]-thymidine incorporation assay. Cells from proestrus rats exhibited lower proliferation than the other groups, which could be countered by both U0126 and raloxifene (a selective estrogen receptor modulator). Serum estradiol levels were detected, and rats with higher levels showed less severity of pulmonary hypertension. Conclusively, endogenous estrogen may alleviate hypoxia-induced pulmonary hypertension by attenuating vasoconstriction through non-genomic mechanisms and inhibiting smooth muscle cells proliferation through both genomic and non-genomic mechanisms.

Biomimetic Nanoparticle-Mediated Target Delivery of Hypoxia-Responsive Plasmid of Angiotensin-Converting Enzyme 2 to Reverse Hypoxic Pulmonary Hypertension.

Hypoxic pulmonary hypertension (HPH) is characterized by pulmonary vascular sustained constriction and progressive remodeling, which are initiated by hypoxia then with hypoxia-induced additive factors including pulmonary vascular endothelium injury, intrapulmonary angiotension system imbalance, and inflammation. Now HPH is still an intractable disease lacking effective treatments. Gene therapy has a massive potential for HPH but is hindered by a lack of efficient targeted delivery and hypoxia-responsive regulation systems for transgenes. Herein, we constructed the hypoxia-responsive plasmid of angiotensin-converting enzyme 2 (ACE2) with endothelial-specific promoter Tie2 and a hypoxia response element and next prepared its biomimetic nanoparticle delivery system, named ACE2-CS-PRT@PM, by encapsulating the plasmid of ACE2 with protamine and chondroitin sulfate as the core then coated it with a platelet membrane as a shell for targeting the injured pulmonary vascular endothelium. ACE2-CS-PRT@PM has a 194.3 nm diameter with a platelet membrane-coating core-shell structure and a negatively charged surface, and it exhibits higher delivery efficiency targeting to pulmonary vascular endothelium and hypoxia-responsive overexpression of ACE2 in endothelial cells in a hypoxia environment. In vitro, ACE2-CS-PRT@PM significantly inhibited the hypoxia-induced proliferation of pulmonary smooth muscle cells. In vivo, ACE2-CS-PRT@PM potently ameliorated the hemodynamic dysfunction and morphological abnormality and largely reversed HPH via inhibiting the hypoxic proliferation of pulmonary artery smooth muscle cells, reducing pulmonary vascular remodeling, restoring balance to the intrapulmonary angiotension system, and improving the inflammatory microenvironment without any detectable toxicity. Therefore, ACE2-CS-PRT@PM is promising for the targeted gene therapy of HPH.

Macrophage migration inhibitory factor contributes to hypoxic pulmonary vasoconstriction in rats.

BACKGROUND: Hypoxic pulmonary vasoconstriction may lead to pulmonary hypertension, but the underlying mechanisms of persistent vasoconstriction are still unclear. There is evidence that pulmonary inflammation contributes to the abnormalities of function in the pulmonary artery (PA) following chronic hypoxia exposure. Macrophage migration inhibitory factor (MIF) is an important pro-inflammatory cytokine, and we found that expression of MIF was increased in the smooth muscle of PA from hypoxic pulmonary hypertensive rats. Therefore, the aim of the study was to investigate the role of MIF in modulating vasoreactivity of isolated PA rings. METHODS: Sprague-Dawley rats were challenged by intermittent chronic hypoxia exposure for 4 weeks to establish hypoxic pulmonary hypertension models. Subsequently, immunohistochemistry and western blot assay were used to examine the MIF expression in pulmonary artery. Moreover, isometric force displacement was measured in isolated intrapulmonary artery. RESULTS: In the isolated PA, our results showed that MIF mediated the enhanced pulmonary arterial vasoconstriction in response to chronic hypoxia, and the delayed hypoxic constriction in a biphasic pattern of constriction occurs in response to acute hypoxia. We also present the finding that MIF had no effect on force on its own, but concentration-dependently potentiated constrictions pre-evoked by phenylephrine under normoxic condition. The potentiation was independent of the endothelium. MIF-induced potentiation of phenylephrine-evoked constriction was partially inhibited by PKC inhibitor chelerythrine, p38 inhibitor SB 203580, ERK1/2 inhibitor U0126, respectively. CONCLUSIONS: Our results suggested that MIF enhanced vasoconstriction of pulmonary artery elicited by agonist through PKC, p38 and ERK1/2 signal pathways, which may contributes to hypoxic pulmonary vasoconstriction.

Insulin reduces LPS-induced lethality and lung injury in rats.

Insulin is a main glucose homeostatic hormone in the body. Previous reports showed that insulin also exerted anti-inflammatory actions and attenuated systemic inflammatory response. Here, we observed the effects and the underlying mechanisms of insulin on lipopolysaccharide (LPS)-induced acute lung injury (ALI). As revealed by survival study, insulin reduced mortality of rats and prolonged their survival time. Meanwhile, insulin significantly reduced the levels of inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), and high mobility group box 1 (HMGB1) in bronchoalveolar lavage fluid (BALF). Besides, insulin markedly inhibited the expression of toll-like receptor 2 (TLR2), toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB). Taken together, these data provided information that insulin attenuated LPS-induced ALI may attribute partly to the inhibition of the production of cytokines, and the expression of TLR2, TLR4 and NF-κB.

Role of macrophage migration inhibitory factor in the proliferation of smooth muscle cell in pulmonary hypertension.

Pulmonary hypertension (PH) contributes to the mortality of patients with lung and heart diseases. However, the underlying mechanism has not been completely elucidated. Accumulating evidence suggests that inflammatory response may be involved in the pathogenesis of PH. Macrophage migration inhibitory factor (MIF) is a critical upstream inflammatory mediator which promotes a broad range of pathophysiological processes. The aim of the study was to investigate the role of MIF in the pulmonary vascular remodeling of hypoxia-induced PH. We found that MIF mRNA and protein expression was increased in the lung tissues from hypoxic pulmonary hypertensive rats. Intensive immunoreactivity for MIF was observed in smooth muscle cells of large pulmonary arteries (PAs), endothelial cells of small PAs, and inflammatory cells of hypoxic lungs. MIF participated in the hypoxia-induced PASMCs proliferation, and it could directly stimulate proliferation of these cells. MIF-induced enhanced growth of PASMCs was attenuated by MEK and JNK inhibitor. Besides, MIF antagonist ISO-1 suppressed the ERK1/2 and JNK phosphorylation induced by MIF. In conclusion, the current finding suggested that MIF may act on the proliferation of PASMCs through the activation of the ERK1/2 and JNK pathways, which contributes to hypoxic pulmonary hypertension.

SIRT6 Protects Against Myocardial Ischemia-Reperfusion Injury by Attenuating Aging-Related CHMP2B Accumulation.

Impaired autophagic flux induces aging-related ischemia vulnerability, which is the hallmark pathology in cardiac aging. Our previous work has confirmed that the accumulation of charged multivesicular body protein 2B (CHMP2B), a subunit of the ESCRT-III complex, in the heart can impair autophagy flux. However, whether CHMP2B accumulation contributes to aging-related intolerance to ischemia/reperfusion (I/R) injury and the regulatory mechanism for CHMP2B in aged heart remain elusive. The cardiac CHMP2B level was significantly higher in aged human myocardium than that in young myocardium. Increased CHMP2B were shown to inhibit autophagic flux leading to the deterioration of MI/R injury in aged mice hearts. Interestingly, a negative correlation was observed between SIRT6 and CHMP2B expression in human heart samples. Specific activation of SIRT6 suppressed CHMP2B accumulation and ameliorated autophagy flux in aged hearts. Using myocardial-specific SIRT6 heterozygous knockout mice and recovery experiments confirmed that SIRT6 regulated myocardial CHMP2B levels. Finally, activation of SIRT6 decreased acetylation of FoxO1 to promote its transcriptional function on Atrogin-1, a muscle-specific ubiquitin ligase, which subsequently enhanced the degradation of CHMP2B by Atrogin-1. This is a novel mechanism for SIRT6 against aging-related myocardial ischemia vulnerability, particularly by preventing excessive accumulation of autophagy key factors.

Association of Metformin with the Mortality and Incidence of Cardiovascular Events in Patients with Pre-existing Cardiovascular Diseases.

INTRODUCTION: Whether metformin reduces all-cause cardiovascular mortality and the incidence of cardiovascular events in patients with pre-existing cardiovascular diseases (CVD) remains inconclusive. Some randomised controlled trials (RCTs) and cohort studies have shown that metformin is associated with an increased risk of mortality and cardiovascular events. METHODS: We conducted a pooling synthesis to assess the effects of metformin in all-cause cardiovascular mortality and incidence of cardiovascular events in patients with CVD. Studies published up to October 2021 in PubMed or Embase with a registration in PROSPERO (CRD42020189905) were collected. Both RCT and cohort studies were included. Hazard ratios (HR) with 95% CI were pooled across various trials using the random-effects model. RESULTS: This study enrolled 35 published studies (in 14 publications) for qualitative synthesis and identified 33 studies (published in 26 publications) for quantitative analysis. We analysed a total of 61,704 patients, among them 58,271 patients were used to calculate all-cause mortality while 12,814 patients were used to calculate cardiovascular mortality. Compared with non-metformin control, metformin usage is associated with a reduction in all-cause mortality (HR: 0.90; 95% CI 0.83, 0.98; p = 0.01), cardiovascular mortality (HR: 0.89; 95% CI 0.85, 0.94; p < 0.0001), incidence of coronary revascularisation (HR: 0.79; 95% CI 0.64, 0.98; p = 0.03), and heart failure (HR: 0.90; 95% CI 0.87, 0.94; p < 0.0001) in patients with pre-existing cardiovascular diseases. CONCLUSION: Metformin use is associated with a reduction in all-cause mortality, cardiovascular mortality, incidence of coronary revascularisation, and heart failure in patients with CVD; however, metformin usage was not associated with reduction in the incidence of myocardial infarction, angina, or stroke.

Phenotype and differentiation of bone marrow-derived smooth muscle progenitor cells.

1. Smooth muscle progenitor cells (SPC) are undifferentiated vascular smooth muscle cells implicated in many hyperplastic diseases of the blood vessels. However, few in vitro studies have investigated the characteristics of SPC. 2. In the present study, we constructed a recombinant plasmid with the enhanced green fluorescent protein (GFP) gene and a rat SM22α promoter, which was exclusively promoted in a smooth muscle cell lineage. Constructs were then transferred into adherent mononuclear cells derived from rat bone marrow. After 3 days, GFP-positive cells, which should be SPC, were isolated by flow cytometry. 3. Flow cytometric analysis and dual immunofluorescent staining showed that the GFP-positive cells expressed both α-smooth muscle actin (a specific marker for smooth muscle) and the chemokine receptor CXCR4 (abundant on precursor cells), but not calmodulin or CD31. After stimulation of SPC with 50 ng/mL platelet-derived growth factor-BB, CXCR4 levels decreased and calmodulin protein content increased, as determined by western blot analysis. 4. On the basis of these results, we conclude that SPC have dual characteristics of both precursor and smooth muscle cells, and might well differentiate into smooth muscle-like cells under certain conditions.

The Pivotal Role of Mitsugumin 53 in Cardiovascular Diseases.

The MG53 (also known as TRIM72) is a conserved, muscle-specific tripartite motif family protein that is abundantly expressed in cardiac or skeletal muscle and present in circulation. Recently, the MG53 had been hypothesized to serve a dual role in the heart: involving in repairing cell membranes that protect myocardial function while acting as an E3 ligase to trigger insulin resistance and cardiovascular complications. This review discusses the roles of MG53 in cardiac physiological function with emphasis on MG53 protective function in the heart and its negative impact on the myocardium due to the continuous elevation of MG53. Besides, this work reviewed the significance of MG53 as a potential therapeutic in human cardiovascular diseases. Despite the expression of MG53 being rare in the human, thus exogenous MG53 can potentially be a new treatment for human cardiovascular diseases. Notably, the specific mechanism of MG53 in cardiovascular diseases remains elusive.

SIRT6 in Senescence and Aging-Related Cardiovascular Diseases.

SIRT6 belongs to the nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases and has established diverse roles in aging, metabolism and disease. Its function is similar to the Silent Information Regulator 2 (SIR2), which prolongs lifespan and regulates genomic stability, telomere integrity, transcription, and DNA repair. It has been demonstrated that increasing the sirtuin level through genetic manipulation extends the lifespan of yeast, nematodes and flies. Deficiency of SIRT6 induces chronic inflammation, autophagy disorder and telomere instability. Also, these cellular processes can lead to the occurrence and progression of cardiovascular diseases (CVDs), such as atherosclerosis, hypertrophic cardiomyopathy and heart failure. Herein, we discuss the implications of SIRT6 regulates multiple cellular processes in cell senescence and aging-related CVDs, and we summarize clinical application of SIRT6 agonists and possible therapeutic interventions in aging-related CVDs.