The supplementation of Rothia as a potential preventive approach for bone loss in mice with ovariectomy-induced osteoporosis.

There is an inseparable link between bone metabolism and gut microbiota, and the supplementation of probiotics exhibits a significant role in maintaining the homeostasis of gut microbiota and inhibiting bone loss. This study aims to explore the preventive and therapeutic potentials and the specific mechanisms of Rothia on osteoporosis. The mice models of osteoporosis induced by ovariectomy (OVX) were built, and the regular (once a day) and quantitative (200 µL/d) gavage of Rothia was performed for 8 weeks starting from 1 week after OVX. Microcomputed tomography was used to analyze the bone mass and bone microstructure of mice in each group after sacrifice. Histological staining and immunohistochemistry were then applied to identify the expression of pro-inflammatory cytokines, intestinal permeability, and osteogenic and osteoclastic activities of mice. The collected feces of mice in each group were used for 16S rRNA high-throughput sequencing to detect the alterations in composition, abundance, and diversity of gut microbiota. This study demonstrated that the gavage of Rothia alleviated bone loss in mice with OVX-induced osteoporosis, improved OVX-induced intestinal mucosal barrier injury, optimized intestinal permeability (zonula occludens protein 1 and occludin), reduced intestinal inflammation (tumor necrosis factor-α and interleukin-1ß), and regulated imbalance of gut microbiota. Based on "gut-bone" axis, this study revealed that regular and quantitative gavage of Rothia can relieve bone loss in mice with OVX-induced osteoporosis by repairing the intestinal mucosal barrier injury, optimizing the intestinal permeability, inhibiting the release of pro-inflammatory cytokines, and improving the disorder of gut microbiota.

Empagliflozin ameliorates vascular calcification in diabetic mice through inhibiting Bhlhe40-dependent NLRP3 inflammasome activation.

Type 2 diabetes mellitus (T2DM) patients exhibit greater susceptibility to vascular calcification (VC), which has a higher risk of death and disability. However, there is no specific drug for VC therapy. NLRP3 inflammasome activation as a hallmark event of medial calcification leads to arterial stiffness, causing vasoconstrictive dysfunction in T2DM. Empagliflozin (EMPA), a sodium-glucose co-transporter 2 inhibitor (SGLT2i), restrains hyperglycemia with definite cardiovascular benefits. Given the anti-inflammatory activity of EMPA, herein we investigated whether EMPA protected against VC in the aorta of T2DM mice by inhibiting NLRP3 inflammasome activation. Since db/db mice receiving a normal diet developed VC at the age of about 20 weeks, we administered EMPA (5, 10, 20 mg·kg-1·d-1, i.g) to 8 week-old db/db mice for 12 weeks. We showed that EMPA intervention dose-dependently ameliorated the calcium deposition, accompanied by reduced expression of RUNX2 and BMP2 proteins in the aortas. We found that EMPA (10 mg·kg-1·d-1 for 6 weeks) also protected against VC in vitamin D3-overloaded mice, suggesting the protective effects independent of metabolism. We showed that EMPA (10 mg·kg-1·d-1) inhibited the abnormal activation of NLRP3 inflammasome in aortic smooth muscle layer of db/db mice. Knockout (KO) of NLRP3 significantly alleviated VC in STZ-induced diabetic mice. The protective effects of EMPA were verified in high glucose (HG)-treated mouse aortic smooth muscle cells (MOVASs). In HG-treated NLRP3 KO MOVASs, EMPA (1 µM) did not cause further improvement. Bioinformatics and Western blot analysis revealed that EMPA significantly increased the expression levels of basic helix-loop-helix family transcription factor e40 (Bhlhe40) in HG-treated MOVASs, which served as a negative transcription factor directly binding to the promotor of Nlrp3. We conclude that EMPA ameliorates VC by inhibiting Bhlhe40-dpendent NLRP3 inflammasome activation. These results might provide potential significance for EMPA in VC therapy of T2DM patients.

Association of lipoprotein(a) with left ventricular hypertrophy in patients with new-onset acute myocardial infarction: A large cross-sectional study.

BACKGROUND: The association of lipoprotein(a) [Lp(a)] with echocardiography-estimated left ventricular hypertrophy (LVH) in high-risk population remains uncertain, so we assessed the association between Lp(a) with echocardiography-derived LVH in patients with new-onset acute myocardial infarction (AMI). METHODS: In this large, single-center, cross-sectional observational study, we enrolled 2,096 patients with new-onset AMI. Lp(a) was used as the independent variable and LVH was used as the dependent variable. Logistic regression, subgroup and sensitivity analysis were performed to test the association of Lp(a) with LVH. RESULTS: The concentration of Lp(a) was higher in LVH group compared with the non-LVH group (P < 0.001). Multivariate logistic regression analysis showed that higher Lp(a) was strongly associated with higher risk of LVH, independently of traditional cardiovascular risk factors (Fully adjusted model, Q4 vs Q1, OR: 1.941, 95% CI: 1.343-2.803, P < 0.001). Subgroup analysis showed that the association of Lp(a) with LVH persisted in the subgroups of age (<60 and ≥60 years), sex (male and female), smoking (yes and no), diabetes (yes), hypertension (yes), hyperlipidemia (yes), and chronic kidney diseases (yes and no). Further sensitivity analysis indicated that Lp(a) remained significantly associated with LVH after further adjusting for high-sensitivity C-reactive protein or excluding patients with estimated glomerular filtration rate < 30 ml/min/1.73 m2 or dividing Lp(a) into multiple dichotomous variables. CONCLUSION: Lp(a) was closely associated with LVH in patients with new-onset AMI.

Association of lipoprotein(a) with all-cause and cause-specific mortality: A prospective cohort study.

BACKGROUND: A growing number of studies have demonstrated a causal association between lipoprotein(a) [Lp(a)] and atherosclerotic cardiovascular diseases (ASCVDs), but its association with all-cause and cause-specific mortality remains unclear. Therefore, this study aimed to explore the association of Lp(a) with all-cause and cause-specific mortality. METHODS: This prospective cohort study included 8,525 participants from the third National Health and Nutrition Examination Survey. Lp(a) was considered an exposure variable, all-cause and cause-specific mortality were used as outcome variables, and all participants were followed from the interview date until death or December 31, 2015. COX proportional hazards regression models, stratified analysis, sensitivity analysis, restricted cubic spline plots and Kaplan-Meier survival curves were used to analyze the association of Lp(a) with all-cause and cause-specific mortality. RESULTS: After adjusting for traditional cardiovascular risk factors, Lp(a) remained strongly associated with all-cause and CVDs-related mortality (P for trend = 0.007 and < 0.001). Subgroup analyses showed that higher Lp(a) remained associated with higher risk of all-cause mortality in those > 60 years of age, with a BMI < 30 kg/m2, and without diabetes, whereas the association between Lp(a) and CVDs-related mortality remained stable in participants ≤ 60 years of age, male, with a BMI < 30 kg/m2, with hypertension, without diabetes, or without CVDs (P < 0.05). In sensitivity analyses, we found that the association of Lp(a) with all-cause and CVDs-related mortality remained robust after excluding individuals who died within one year of follow-up (P for trend = 0.041 and 0.002). CONCLUSIONS: Lp(a) was associated with the risk of all-cause and CVDs-related mortality.

Programmed cell death in atherosclerosis and vascular calcification.

The concept of cell death has been expanded beyond apoptosis and necrosis to additional forms, including necroptosis, pyroptosis, autophagy, and ferroptosis. These cell death modalities play a critical role in all aspects of life, which are noteworthy for their diverse roles in diseases. Atherosclerosis (AS) and vascular calcification (VC) are major causes for the high morbidity and mortality of cardiovascular disease. Despite considerable advances in understanding the signaling pathways associated with AS and VC, the exact molecular basis remains obscure. In the article, we review the molecular mechanisms that mediate cell death and its implications for AS and VC. A better understanding of the mechanisms underlying cell death in AS and VC may drive the development of promising therapeutic strategies.

Factors predicting the occurrence of aortic valve calcification in patients with coronary artery calcification in China.

OBJECTIVES: In patients with coronary artery calcification (CAC), a predictor of adverse cardiovascular events, coronary computed tomography angiography (CCTA) also shows valvular calcification. In this study, we evaluated common clinical indicators in CAC patients with aortic (AoVC) and mitral valve (MVC) calcification. METHODS: CAC and valvular calcification were quantified using the Agatston score in 636 hospitalised patients with CAC who underwent CCTA. RESULTS: Valvular calcification was found in 30.5% of patients, with 25.2% (160 patients) showing AoVC. Age was an independent predictor of AoVC in both men (odds ratio (OR), 1.086; 95% confidence interval (CI), [1.054-1.119]; p < 0.001) and women (OR, 1.109; CI, [1.066-1.154]; p < 0.001). In men, we also found that a history of cerebral infarction was an independent predictor of AoVC (OR, 2.402; CI, [1.177-4.902]; p < 0.05). The independent predictors of AoVC in the 60- to 69-years age group were BMI (OR, 1.181; CI, [1.061-1.316]; p < 0.01) and history of cerebral infarction (OR, 3.187; CI, [1.283-7.919]; p < 0.05). CONCLUSIONS: Age is a key independent predictor of AoVC in CAC patients. History of cerebrovascular disease was also an independent predictor of AoVC, but only in men and patients aged 60-69 years. Our results indicate that a history of cerebral infarction may be used as a risk factor when identifying AoVC in patients with CAC.

Correlation analysis of coronary artery tortuosity and calcification score.

BACKGROUND: Coronary artery tortuosity (CAT) is regarded as a variation of vascular anatomy, and its relationship with coronary artery calcification (CAC) score is still not well clarified. Studying the correlation between coronary artery calcification scores and CAT to determine specific prevention and intervention populations seems to have more meaningful. METHODS: The study is a cross-sectional retrospective study, including 1280 patients. CAT is defined as the presence of at least three consecutive curvatures of more than 45°measured during systole or diastole of a major epicardial coronary artery. Multivariable regression analysis was used to adjust the clinical parameters directly affecting CAT. RESULTS: Of these individuals, 445 (35%) were evaluated having CAT, of which females are higher than males (59.1% vs. 40.9%). Moderate CAC score (101-400) (odds ratio (OR) 1.49, 95% confidence interval [95%CI] 1.05-2.10, P = 0.025) revealed significantly associated with CAT on univariable analysis. However, multivariable analysis after adjusting for confounding factors only indicated that CAT was positively correlated with female (OR 1.68, 95%CI 1.30-2.17, P < 0.001), hypertension (OR 1.35, 95% CI 1.04-1.75, P = 0.024), and age (OR 1.02, 95% CI 1.01-1.03, P = 0.001), while was negatively associated with body mass index (BMI) 24-27.9(OR 0.76, 95% CI 0.58-1.00, P = 0.044), and BMI > 28 (OR 0.46, 95% CI 0.31-0.68, P < 0.001). Further analysis stratified by gender showed that compared with non-CAT, CAT was significantly linked with moderate CAC score (OR 1.79, 95% CI 1.00-3.20, P = 0.048), hypertension (OR 1.54, 95% CI 1.07-2.22, P = 0.021), and high-density lipoprotein (HDL) (OR 1.86, 95% CI 1.07-3.24, P = 0.028), while was negatively related to BMI > 28 (OR 0.51, 95% CI 0.31-0.84, P = 0.008) in female patients. CONCLUSIONS: CAT is more likely to be found in females, connected with hypertension, age, and BMI. No significant correlation is found between the presence of tortuosity and calcium score or diameter stenosis on multivariable analysis. Whereas the CAT is associated with moderate CAC score in correlation analysis when women are selected as the main group.

Association between hemoglobin glycation index and subclinical myocardial injury in the general population free from cardiovascular disease.

BACKGROUND AND AIMS: The relationship between hemoglobin glycation index (HGI) and the diagnosis and prognosis of cardiovascular disease (CVD) has been verified by previous studies. However, it remains unknown whether HGI has a predictive effect on subclinical myocardial injury (SC-MI). The purpose of the present study was to explore the relationship between HGI and SC-MI in the general population free from CVD. METHODS AND RESULTS: The present study included 6009 participants free of CVD from the third National Health and Nutrition Examination Survey. Binary Logistic regression analysis was used to tested the association between HGI and SC-MI. As results, the HGI was significantly higher in participants with SC-MI compared with those without, and the HGI was positively correlated with SC-MI and other metabolic disorder parameters. Each 1-unit increase of HGI and glycated hemoglobin A1c (HbA1c) was independently associated with higher risk of SC-MI (P < 0.05), while fasting plasma glucose (FPG) was no longer a predictive indicator of SC-MI with the increase of confounding factors [OR (95% CI): 1.001 (0.999-1.003), P = 0.305]. And in the subgroup analysis, HGI, only in participants without diabetes, was independently associated with higher risk of SC-MI, while HbA1c and FPG had no independent predictive role in both diabetic and non-diabetic participants. CONCLUSIONS: HGI was a significant predictor of SC-MI in the general population free from CVD.

Diabetic mellitus, vascular calcification and hypoxia: A complex and neglected tripartite relationship.

DM (diabetic mellitus) and its common vascular complications VC (vascular calcification), are increasingly harmful to human health. In recent years, the research on the relationship between DM and VC is also deepening. Hypoxia, as one of the pathogenic factors of many disease models, is also closely related to the occurrence of DM and VC. There are some studies on the role of hypoxia in the pathogenesis of DM and VC respectively, but no one has made an in-depth summary of the systematic connection between hypoxia, DM and VC. Therefore, what we want to review in this article are the relationship between DM, VC and hypoxia, respectively, as well as the role of hypoxia in the development of DM and VC, which has little concern but is a novel and potentially target that may provide some new ideas for the prevention and treatment of DM, VC, especially diabetic VC.

Periostin promotes arterial calcification through PPARγ-related glucose metabolism reprogramming.

Extracellular matrix (ECM) exerts a series of biological functions and contributes to almost 30% of the osteogenic process. Periostin is a secreted protein that can alter ECM remodeling in response to vascular injury. However, the role of periostin in vascular calcification has yet to be fully investigated. As found in this study, recombinant periostin accelerated the thoracic aortas calcification, increased the expression of glycolysis key enzymes, and disturbed the normal oxidative phosphorylation (OXPHOS) ex vivo, which could be alleviated by the peroxisome proliferation-activated receptor γ (PPARγ) agonist pioglitazone. In vascular smooth muscle cells (VSMCs), periostin promoted VSMC-osteoblastic phenotype transition and calcium deposition and suppressed PPARγ expression. Mechanistically, periostin caused overactivation of glycolysis and mitochondrial dysfunction in VSMCs as assessed by extracellular acidification rate, oxygen consumption rate, and mitochondrial respiratory chain complex activities. Targeted glycolysis inhibitors reduced mitochondrial calcium overload, apoptosis, and periostin-induced VSMCs calcification. PPARγ agonists preserved glycolysis and OXPHOS in the stimulated microenvironment and reversed periostin-promoted VSMC calcification. Furthermore, plasma periostin, lactate, and matrix Gla protein levels were measured in 274 patients undergoing computed tomography to determine coronary artery calcium score (Agatston score). Plasma periostin and lactate levels were both linked to an Agatston score in patients with coronary artery calcification (CAC). There was also a positive correlation between plasma periostin and lactate levels. This study suggests that downregulation of PPARγ is involved in the mechanism by which periostin accelerates arterial calcification partly through excessive glycolysis activation and unbalanced mitochondrial homeostasis.NEW & NOTEWORTHY Periostin caused arterial calcification, overactivated glycolysis, and damaged OXPHOS. PPARγ agonists alleviated periostin-promoted arterial calcification and corrected abnormal glycolysis and unbalanced mitochondrial homeostasis. There exists a relationship between periostin and lactate in patients with CAC.

POSTN promotes diabetic vascular calcification by interfering with autophagic flux.

Autophagy is a lysosomal degradative process that is closely related to the pathogenesis of vascular calcification. Recent evidence suggests that periostin (POSTN) is a unique extracellular matrix protein that is associated with diabetic vascular complications. The aim of current study is to investigate the role of POSTN in diabetic vascular calcification and the underlying mechanisms. Results showed that POSTN was highly upregulated in both calcified arteries of diabetic rats and AGEs-BSA mediated vascular smooth muscle cell (VSMC) calcification. POSTN blocked autophagic flux during the diabetic calcification process, as evidenced by increased protein expression of Beclin1, LC3-II, and P62, as well as the co-localization of LC3-II and LAMP1. Inhibition of POSTN alleviated AGEs-BSA-induced autophagic flux blockade, thereby attenuating AGEs-BSA-induced VSMC calcification. Mechanistically, the upregulation of POSTN impaired the fusion of autophagosomes and lysosome and resulted in the autophagic flux blockade in AGEs-BSA-treated VSMC. Furthermore, this autophagic blockade was intracellular ROS-dependent. In summary, this study uncovered a novel mechanism of POSTN in autophagy regulation of diabetic vascular calcification.

Mitochondria Homeostasis and Vascular Medial Calcification.

Vascular calcification occurs highly prevalent, which commonly predicts adverse cardiovascular events. The pathogenesis of calcification, a complicated and multifactorial process, is incompletely characterized. Accumulating evidence shows that mitochondrial dysfunction may ultimately be more detrimental in the vascular smooth muscle cells (VSMCs) calcification. This review summarizes the role of mitochondrial dysfunction and metabolic reprogramming in vascular calcification, and indicates that metabolic regulation may be a therapeutic target in vascular calcification.

Metformin attenuates hyperlipidaemia-associated vascular calcification through anti-ferroptotic effects.

Ferroptosis is a form of regulated cell death that involves metabolic dysfunction resulting from iron-dependent excessive lipid peroxidation. Elevated plasma levels of free fatty acids are tightly associated with cardiometabolic risk factors in patients with obesity, diabetes mellitus, and metabolic syndrome. Metformin (Met) is an antidiabetic drug with beneficial cardiovascular disease effects. The aim of this study was to determine the effects of Met on ferroptosis induced by lipid overload and the effects of these changes on vascular smooth muscle cells (VSMCs) calcification. We developed a hyperlipidaemia-related vascular calcification in vivo model with rats fed a high-fat diet combined with vitamin D3 plus nicotine, and palmitic acid (PA), the most abundant long-chain saturated fatty acid in plasma, was used to induce lipid overload and develop an oxidative stress-related calcification model in vitro. The results showed that Met inhibits hyperlipidaemia-associated calcium deposition in the rat aortic tissue. In vitro, treatment of VSMCs with PA stimulates ferroptosis concomitant with increased calcium deposition in VSMCs, while pretreatment with Met attenuates these effects. Furthermore, PA also promotes the protein expression of the extracellular matrix protein periostin (POSTN) and its secretion into the extracellular environment. More importantly, upregulation of POSTN increased the sensitivity of cells to ferroptosis. Mechanistically, upregulation of POSTN suppresses SLC7A11 expression through the inhibition of p53 in VSMCs, which contributes to a decrease in glutathione synthesis and therefore triggers ferroptosis. Interestingly, overexpression of p53 attenuates the inhibitory effect of POSTN on SLC7A11 expression, accompanied by increased Gpx4 expression. Furthermore, p53 knockdown suppresses Met-mediated anti-ferroptosis effects in PA-treated VSMCs, which may be related to the downregulation of SLC7A11 expression. In addition, supplementation of VSMCs with Met enhances the antioxidative capacity of VSMCs through Nrf2 signalling activation. Collectively, targeting POSTN in VSMCs may provide a new strategy for vascular calcification prevention or treatment.

PDK4 promotes vascular calcification by interfering with autophagic activity and metabolic reprogramming.

Pyruvate dehydrogenase kinase 4 (PDK4) is an important mitochondrial matrix enzyme in cellular energy regulation. Previous studies suggested that PDK4 is increased in the calcified vessels of patients with atherosclerosis and is closely associated with mitochondrial function, but the precise regulatory mechanisms remain largely unknown. This study aims to investigate the role of PDK4 in vascular calcification and the molecular mechanisms involved. Using a variety of complementary techniques, we found impaired autophagic activity in the process of vascular smooth muscle cells (VSMCs) calcification, whereas knocking down PDK4 had the opposite effect. PDK4 drives the metabolic reprogramming of VSMCs towards a Warburg effect, and the inhibition of PDK4 abrogates VSMCs calcification. Mechanistically, PDK4 disturbs the integrity of the mitochondria-associated endoplasmic reticulum membrane, concomitantly impairing mitochondrial respiratory capacity, which contributes to a decrease in lysosomal degradation by inhibiting the V-ATPase and lactate dehydrogenase B interaction. PDK4 also inhibits the nuclear translocation of the transcription factor EB, thus inhibiting lysosomal function. These changes result in the interruption of autophagic flux, which accelerates calcium deposition in VSMCs. In addition, glycolysis serves as a metabolic adaptation to improve VSMCs oxidative stress resistance, whereas inhibition of glycolysis by 2-deoxy-D-glucose induces the apoptosis of VSMCs and increases the calcium deposition in VSMCs. Our results suggest that PDK4 plays a key role in vascular calcification through autophagy inhibition and metabolic reprogramming.

Lactate accelerates vascular calcification through NR4A1-regulated mitochondrial fission and BNIP3-related mitophagy.

Arterial media calcification is related to mitochondrial dysfunction. Protective mitophagy delays the progression of vascular calcification. We previously reported that lactate accelerates osteoblastic phenotype transition of VSMC through BNIP3-mediated mitophagy suppression. In this study, we investigated the specific links between lactate, mitochondrial homeostasis, and vascular calcification. Ex vivo, alizarin S red and von Kossa staining in addition to measurement of calcium content, RUNX2, and BMP-2 protein levels revealed that lactate accelerated arterial media calcification. We demonstrated that lactate induced mitochondrial fission and apoptosis in aortas, whereas mitophagy was suppressed. In VSMCs, lactate increased NR4A1 expression, leading to activation of DNA-PKcs and p53. Lactate induced Drp1 migration to the mitochondria and enhanced mitochondrial fission through NR4A1. Western blot analysis of LC3-II and p62 and mRFP-GFP-LC3 adenovirus detection showed that NR4A1 knockdown was involved in enhanced autophagy flux. Furthermore, NR4A1 inhibited BNIP3-related mitophagy, which was confirmed by TOMM20 and BNIP3 protein levels, and LC3-II co-localization with TOMM20. The excessive fission and deficient mitophagy damaged mitochondrial structure and impaired respiratory function, determined by mPTP opening rate, mitochondrial membrane potential, mitochondrial morphology under TEM, ATP production, and OCR, which was reversed by NR4A1 silencing. Mechanistically, lactate enhanced fission but halted mitophagy via activation of the NR4A1/DNA-PKcs/p53 pathway, evoking apoptosis, finally accelerating osteoblastic phenotype transition of VSMC and calcium deposition. This study suggests that the NR4A1/DNA-PKcs/p53 pathway is involved in the mechanism by which lactate accelerates vascular calcification, partly through excessive Drp-mediated mitochondrial fission and BNIP3-related mitophagy deficiency.

Lactate accelerates calcification in VSMCs through suppression of BNIP3-mediated mitophagy.

Arterial media calcification is one of the major complications of diabetes mellitus, which is related to oxidative stress and apoptosis. Mitophagy is a special regulation of mitochondrial homeostasis and takes control of intracellular ROS generation and apoptotic pathways. High circulating levels of lactate usually accompanies diabetes. The potential link between lactate, mitophagy and vascular calcification is investigated in this study. Lactate treatment accelerated VSMC calcification, evaluated by measuring the calcium content, ALP activity, RUNX2, BMP-2 protein levels, and Alizarin red S staining. Lactate exposure caused excessive intracellular ROS generation and VSMC apoptosis. Lactate also impaired mitochondrial function, determined by mPTP opening rate, mitochondrial membrane potential and mitochondrial biogenesis markers. Western blot analysis of LC3-II and p62 and mRFP-GFP-LC3 adenovirus detection for autophagy flux revealed that lactate blocked autophagy flux. LC3-II co-staining with LAMP-1 and autophagosome quantification revealed lactate inhibited autophagy. Furthermore, lactate inhibited mitophagy, which was confirmed by TOMM20 and BNIP3 protein levels, LC3-II colocalization with BNIP3 and TEM assays. In addition, BNIP3-mediated mitophagy played a protective role against VSMC calcification in the presence of lactate. This study suggests that lactate accelerates osteoblastic phenotype transition of VSMC and calcium deposition partly through the BNIP3-mediated mitophagy deficiency induced oxidative stress and apoptosis.

Impact of smoking on all-cause mortality and cardiovascular events in patients after coronary revascularization with a percutaneous coronary intervention or coronary artery bypass graft: a systematic review and meta-analysis.

Although cigarette smoking is an independent risk factor for cardiovascular disease, inconsistent results have been published in the literature on its impacts on the cardiovascular health of patients after coronary revascularization with a percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG). We performed a comprehensive electronic database search through July 2018. Studies reporting the risk estimates of all-cause mortality and cardiovascular outcomes in patients after coronary revascularization with PCI or CABG on the basis of smoking status were selected. Multivariate-adjusted relative risks (RRs) and 95% confidence intervals (CIs) were pooled using random-effects models with inverse variance weighting. Data from 37 records including 126 901 participants were finally collected. Overall, the pooled RR (95% CI) associated with cigarette smoking was 1.26 (95% CI: 1.09-1.47) for all-cause mortality, 1.08 (95% CI: 0.92-1.28) for major adverse cardiovascular events, 0.96 (95% CI: 0.69-1.35) for cardiovascular mortality and 1.15 (95% CI: 0.81-1.64) for myocardial infarction. The increased risk of all-cause mortality was also observed in former smokers compared with those who had never smoked (RR: 1.19; 95% CI: 1.03-1.38). Furthermore, the negative effects of cigarette smoking on all-cause mortality were also observed in most subgroups. Cigarette smoking has been shown to increase the likelihood of all-cause mortality in patients after coronary revascularization with PCI or CABG. Smoking cessation is essential for PCI or CABG patients to manage their coronary artery disease.

Restoring mitochondrial biogenesis with metformin attenuates ß-GP-induced phenotypic transformation of VSMCs into an osteogenic phenotype via inhibition of PDK4/oxidative stress-mediated apoptosis.

Mitochondrial abnormalities have long been observed in the development of vascular calcification. Metformin, a member of the biguanide class of antidiabetic drugs, has recently received attention owing to new findings regarding its protective role in cardiovascular disease. Since the precise control of mitochondrial quantity and quality is critical for the survival and function of vascular smooth muscle cells (VSMCs), maintaining mitochondrial homeostasis may be a potential protective factor for VSMCs against osteoblast-like phenotypic transition. However, limited studies have been reported in this area. Here, we investigated the role of metformin in the phenotypic transformation of VSMCs, as well as its intracellular signal transduction pathways. We demonstrated that supplementation with metformin restored the ß-glycerophosphate (ß-GP)-mediated impairment of mitochondrial biogenesis in VSMCs, as evidenced by an increased mitochondrial DNA copy number, a restored mitochondrial membrane potential (MMP), and upregulated mitochondrial biogenesis-related gene expression, whereas the AMP-activated protein kinase (AMPK) inhibitor compound C suppressed these effects. We also observed that overexpression of pyruvate dehydrogenase kinase 4 (PDK4), an important mitochondrial matrix enzyme in cellular energy metabolism, exacerbated ß-GP-induced oxidative stress and subsequent apoptosis in VSMCs but that these effects were suppressed by dichloroacetate, a widely reported PDK4 inhibitor. More importantly, enhanced mitochondrial biogenesis attenuated the ß-GP-induced phenotypic transformation of VSMCs into an osteogenic phenotype through inhibition of the PDK4/oxidative stress-mediated apoptosis pathway, whereas disruption of mitochondrial biogenesis by zidovudine aggravated ß-GP-induced apoptosis in VSMCs. In addition, inhibition of autophagy by small interfering RNA targeting Atg5 reduced mitochondrial biogenesis in VSMCs. In summary, we uncovered a novel mechanism by which metformin attenuates the phenotypic transformation of VSMCs into an osteogenic phenotype via inhibition of the PDK4/oxidative stress-mediated apoptosis pathway, and mitochondrial homeostasis is involved in this process.

Advanced glycation end products accelerate calcification in VSMCs through HIF-1α/PDK4 activation and suppress glucose metabolism.

Arterial media calcification is associated with diabetes mellitus. Previous studies have shown that advanced glycation end products (AGEs) are responsible for vascular smooth muscle cell (VSMC) calcification, but the underlying mechanisms remain unclear. Hypoxia-inducible factor-1α (HIF-1α), one of the major factors during hypoxia, and pyruvate dehydrogenase kinase 4 (PDK4), an important mitochondrial matrix enzyme in cellular metabolism shift, have been reported in VSMC calcification. The potential link among HIF-1α, PDK4, and AGEs-induced vascular calcification was investigated in this study. We observed that AGEs elevated HIF-1α and PDK4 expression levels in a dose-dependent manner and that maximal stimulation was attained at 24 h. Two important HIF-1α-regulated genes, vascular endothelial growth factor A (VEGFA) and glucose transporter 1 (GLUT-1), were significantly increased after AGEs exposure. Stabilization or nuclear translocation of HIF-1α increased PDK4 expression. PDK4 inhibition attenuated AGEs-induced VSMC calcification, which was evaluated by measuring the calcium content, alkaline phosphatase (ALP) activity and runt-related transcription factor 2 (RUNX2) expression levels and by Alizarin red S staining. In addition, the glucose consumption, lactate production, key enzymes of glucose metabolism and oxygen consumption rate (OCR) were decreased during AGEs-induced VSMC calcification. In conclusion, this study suggests that AGEs accelerate vascular calcification partly through the HIF-1α/PDK4 pathway and suppress glucose metabolism.

Involvement of brain-derived neurotrophic factor in exercise­induced cardioprotection of post-myocardial infarction rats.

Exercise induces a number of benefits, including angiogenesis in post­myocardial infarction (MI); however, the underlying mechanisms have not been fully clarified. Neurotrophic brain­derived neurotrophic factor (BDNF) serves a protective role in certain adult cardiac diseases through its specific receptor, BDNF/NT­3 growth factors receptor (TrkB). The present study explored the mechanisms by which exercise improves cardiac function, with a focus on the involvement of the BDNF/TrkB axis. MI rats were assigned to Sham, sedentary, exercise, exercise with K252a (a TrkB inhibitor), and exercise with NG­nitro­L­arginine methyl ester (L­NAME) groups. The exercise group was subjected to 8 weeks of treadmill running. The results demonstrated that the rats in the exercise group exhibited increased myocardial angiogenesis and improved cardiac function, which was attenuated by K252a. Exercise induced activation of the BDNF/TrkB axis in the ischaemic myocardium and increased serum BDNF levels were abated by exposure to L­NAME. Improvements in angiogenesis and left ventricular function exhibited a positive association, with changes in serum BDNF. In the in vitro experiments, human umbilical vein endothelial cells were exposed to shear stress (SS) of 12 dyn/cm2 to mimic the effects of exercise training on vascular tissue. An increased tube­forming capacity, and a nitric oxide (NO)­dependent prolonged activation of the BDNF/TrkB­full­length axis over 12 h, but not the TrkB­truncated axis, was observed. The SS­related angiogenic response was attenuated by TrkB inhibition. Overall, these results demonstrate that exercise confers certain aspects of its cardioprotective effects through the activation of the BDNF/TrkB axis in an NO­dependent manner, a process in which fluid­induced SS may serve a crucial role.