Cardiovascular risk and atherosclerosis prevention. Cardiovasc Pathol. 2013;22:16-18. [PMID: 22502868 DOI: 10.1016/j.carpath.2012.03.001]

Circ_0090231 knockdown protects vascular smooth muscle cells from ox-LDL-induced proliferation, migration and invasion via miR-942-5p/PPM1B axis during atherosclerosis

Atherosclerosis (AS) is a dominant pathological basis of cardiovascular disease. Circular RNAs (circRNAs) have been proposed to have crucial functions in regulating pathological progressions of AS. Hence, the aim of this study was to investigate the potential function of circ_0090231 in AS progression. Oxidized low densitylipoprotein (ox-LDL)-challenged vascular smooth muscle cells (VSMCs) were used for in vitro functional analysis. Levels of genes and proteins were measured by qRT-PCR and Western blot. The proliferation, migration and invasion were assessed using cell counting kit-8, 5-ethynyl-2'-deoxyuridine, and transwell assays. The interaction between miR-942-5p and circ_0090231 or PPM1B (Protein Phosphatase, Mg2+/Mn2+ Dependent 1B) was evaluated by dual-luciferase reporter and pull-down assays. Circ_0090231 is a stable circRNA, and was increased in the serum of AS patients and ox-LDL-challenged VSMCs. Functionally, silencing of circ_0090231 could reverse ox-LDL-induced proliferation, migration and invasion in VSMCs. Mechanistically, circ_0090231 directly targeted miR-942-5p, and PPM1B was a target of miR-942-5p. Besides, circ_0090231 sequestered miR-942-5p to release PPM1B expression, suggesting the circ_0090231/miR-942-5p/PPM1B axis. Further rescue experiments showed that miR-942-5p inhibition or ectopic overexpression of PPM1B dramatically attenuated the suppressing influences of circ_0090231 knockdown on VSMC proliferative, migratory and invasive abilities under ox-LDL treatment. Silencing of circ_0090231 could reverse ox-LDL-induced proliferation, migration and invasion in VSMCs via miR-942-5p/PPM1B axis, providing a theoretical basis for elucidating the mechanism of AS process.

Ferroptosis: a potential target for the treatment of atherosclerosis

Atherosclerosis (AS), the main contributor to acute cardiovascular events, such as myocardial infarction and ischemic stroke, is characterized by necrotic core formation and plaque instability induced by cell death. The mechanisms of cell death in AS have recently been identified and elucidated. Ferroptosis, a novel iron-dependent form of cell death, has been proven to participate in atherosclerotic progression by increasing endothelial reactive oxygen species (ROS) levels and lipid peroxidation. Furthermore, accumulated intracellular iron activates various signaling pathways or risk factors for AS, such as abnormal lipid metabolism, oxidative stress, and inflammation, which can eventually lead to the disordered function of macrophages, vascular smooth muscle cells, and vascular endothelial cells. However, the molecular pathways through which ferroptosis affects AS development and progression are not entirely understood. This review systematically summarizes the interactions between AS and ferroptosis and provides a feasible approach for inhibiting AS progression from the perspective of ferroptosis.

The role of immune system in atherosclerosis: Molecular mechanisms, controversies, and future possibilities

Numerous cardiovascular disorders have atherosclerosis as their pathological underpinning. Numerous studies have demonstrated that, with the aid of pattern recognition receptors, cytokines, and immunoglobulins, innate immunity, represented by monocytes/macrophages, and adaptive immunity, primarily T/B cells, play a critical role in controlling inflammation and abnormal lipid metabolism in atherosclerosis. Additionally, the finding of numerous complement components in atherosclerotic plaques suggests yet again how heavily the immune system controls atherosclerosis. Therefore, it is essential to have a thorough grasp of how the immune system contributes to atherosclerosis. The specific molecular mechanisms involved in the activation of immune cells and immune molecules in atherosclerosis, the controversy surrounding some immune cells in atherosclerosis, and the limitations of extrapolating from relevant animal models to humans were all carefully reviewed in this review from the three perspectives of innate immunity, adaptive immunity, and complement system. This could provide fresh possibilities for atherosclerosis research and treatment in the future.

Circ-C16orf62 Regulates Oxidized low-density Lipoprotein-induced Apoptosis, Inflammation, Oxidative Stress and Cholesterol Accumulation of Macrophages via Mediating RAB22A Expression by Targeting miR-377

Atherosclerosis (AS) is one of the most common and important vascular diseases. It is believed that the abnormal expression of circular RNAs (circRNAs) plays an important role in AS. Hence, we investigate the function and mechanism of circ-C16orf62 in AS development.In this study, oxidized low-density lipoprotein (ox-LDL)-treated human macrophages (THP-1) were used as pathological conditions of AS in vitro. The expression of circ-C16orf62, miR-377 and Ras-related protein (RAB22A) mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR) or western blot. Cell viability or cell apoptosis was assessed by cell counting kit-8 (CCK-8) assay or flow cytometry assay. The releases of proinflammatory factors were investigated using enzyme-linked immunosorbent assay (ELISA). The production of malondialdehyde (MDA) and superoxide dismutase (SOD) was examined to assess oxidative stress. Total cholesterol (T-CHO) level was detected, and cholesterol efflux level was tested using a liquid scintillation counter. The putative relationship between miR-377 and circ-C16orf62 or RAB22A was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.circ-C16orf62 expression was elevated in AS serum samples and ox-LDL-treated THP-1 cells. Apoptosis, inflammation, oxidative stress and cholesterol accumulation induced by ox-LDL were suppressed by circ-C16orf62 knockdown. Circ-C16orf62 could bind to miR-377 and thus increased the expression level of RAB22A. Rescued experiments showed that circ-C16orf62 knockdown alleviated ox-LDL-induced THP-1 cell injuries by increasing miR-377 expression, and miR-377 overexpression lessened ox-LDL-induced THP-1 cell injuries by degrading RAB22A level.In conclusion, circ-C16orf62 played a crucial role in the regulation of apoptosis, inflammation, oxidative stress and cholesterol accumulation in ox-LDL-treated human macrophages via mediating the miR-377/RAB22A axis, hinting that circ-C16orf62 might be involved in AS progression.

Birth size, growth trajectory and later cardio-metabolic risk

There is increasing evidence of a strong association between intrauterine growth and subsequent development of chronic disease in adult life. Birth size and growth trajectory have been demonstrated to have an impact on cardio-metabolic health, both in childhood and adult life. Hence, careful observation of the children's growth pattern, starting from the intrauterine period and the first years of life, should be emphasized to detect the possible onset of cardio-metabolic sequelae. This allows to intervene on them as soon as they are detected, first of all through lifestyle interventions, whose efficacy seems to be higher when they are started early. Recent papers suggest that prematurity may constitute an independent risk factor for the development of cardiovascular disease and metabolic syndrome, regardless of birth weight. The purpose of the present review is to examine and summarize the available knowledge about the dynamic association between intrauterine and postnatal growth and cardio-metabolic risk, from childhood to adulthood.

Circular RNA circ_0008896 contributes to oxidized low-density lipoprotein-induced aortic endothelial cell injury via targeting miR-188-3p/NOD2 axis

We aimed to investigate the role and mechanism of circ_0008896 in Atherosclerosis (AS) by using oxidized low-density lipoprotein (ox-LDL)-induced human aortic endothelial cell (HAECs). Levels of genes and proteins were measured by quantitative real-time PCR and Western blot. Functional experiments, including enzyme-linked immunosorbent assay analysis, cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, tube formation assays and the detection of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) generation, were performed to investigate the role of circ_0008896 on ox-LDL-induced HAEC damage. Circ_0008896 was increased in AS patients and ox-LDL-stimulated HAECs. Functionally, circ_0008896 knockdown reversed ox-LDL-induced inflammatory response, oxidative stress, apoptosis as well as arrest of proliferation and angiogenesis in HAECs in vitro. Mechanistically, circ_0008896 functioned as a sponge for miR-188-3p to relieve the repression of miR-188-3p on its target NOD2. A series of rescue experiments showed that miR-188-3p inhibition attenuated the protective effects of circ_0008896 knockdown on ox-LDL-stimulated HAECs, and NOD2 overexpression abolished the beneficial action of miR-188-3p in the suppression of inflammatory response and oxidative stress, and the promotion of cell growth and angiogenesis in HAECs under ox-LDL treatment. Circ_0008896 silencing attenuates ox-LDL-induced inflammatory response, oxidative stress, and growth arrest in HAECs in vitro, adding further understanding for the pathogenesis of AS.

Melatonin and cardiovascular disease: from mechanisms of action to potential clinical use (literature review)

Cardiovascular disease remains the most relevant public health problem. Most cardiovascular diseases are associated with an atherosclerosis, the development of which is associated with inflammation and endothelial dysfunction. Melatonin is a neurohormone that is synthesized mainly in the pineal gland and plays a central role in the regulation of sleep and some other body cyclic processes. For a long time, melatonin was perceived as a substance that is effective in the treatment of circadian cycle impairments. At the same time, a large number of studies have accumulated recently that demonstrate a wider range of its biological effects, including anti-inflammatory, antioxidant, antihypertensive and, possibly, hypolipidemic. The review includes current data from experimental and clinical studies demonstrating the cardioprotective effects of melatonin in atherosclerosis, myocardial ischemia, and heart failure.

Non-coding RNA-based regulation of inflammation

Inflammation is a multifactorial process and various biological mechanisms and pathways participate in its development. The presence of inflammation is involved in pathogenesis of different diseases such as diabetes mellitus, cardiovascular diseases and even, cancer. Non-coding RNAs (ncRNAs) comprise large part of transcribed genome and their critical function in physiological and pathological conditions has been confirmed. The present review focuses on miRNAs, lncRNAs and circRNAs as ncRNAs and their potential functions in inflammation regulation and resolution. Pro-inflammatory and anti-inflammatory factors are regulated by miRNAs via binding to 3'-UTR or indirectly via affecting other pathways such as SIRT1 and NF-κB. LncRNAs display a similar function and they can also affect miRNAs via sponging in regulating levels of cytokines. CircRNAs mainly affect miRNAs and reduce their expression in regulating cytokine levels. Notably, exosomal ncRNAs have shown capacity in inflammation resolution. In addition to pre-clinical studies, clinical trials have examined role of ncRNAs in inflammation-mediated disease pathogenesis and cytokine regulation. The therapeutic targeting of ncRNAs using drugs and nucleic acids have been analyzed to reduce inflammation in disease therapy. Therefore, ncRNAs can serve as diagnostic, prognostic and therapeutic targets in inflammation-related diseases in pre-clinical and clinical backgrounds.

Circ_CHFR Promotes Platelet-Derived Growth Factor-BB-Induced Proliferation, Invasion, and Migration in Vascular Smooth Muscle Cells via the miR-149-5p/NRP2 Axis

ABSTRACT

Circular RNA checkpoint with forkhead and ring finger domains (circ_CHFR) were reported to regulate vascular smooth muscle cell (VSMC) dysfunction during atherosclerosis (AS). However, the molecule mechanism of circ_CHFR in AS remains largely unclear. Human VSMCs (HVSMCs) were exposed to platelet-derived growth factor-BB (PDGF-BB) in vitro. Levels of circ_CHFR, microRNA (miR)-149-5p, and neuropilin 2 (NRP2) were determined using quantitative real-time polymerase chain reaction and western blot. Cell proliferation, migration, and invasion were analyzed using cell counting kit-8, colony formation, flow cytometry, wound healing, and transwell assays. The binding interaction between miR-149-5p and circ_CHFR or NRP2 was investigated using the dual-luciferase reporter and RNA immunoprecipitation assays. Circ_CHFR was elevated in PDGF-BB-induced HVSMCs in a dose-independent manner. Silencing of circ_CHFR reversed PDGF-BB-evoked promotion of cell proliferation, migration and invasion, as well as suppression of cell apoptosis in HVSMCs. Mechanistically, circ_CHFR directly bound to miR-149-5p, and miR-149-5p inhibition attenuated the effects of circ_CHFR knockdown on PDGF-BB-induced HVSMCs. Besides, NRP2 was confirmed to be a target of miR-149-5p, and circ_CHFR could regulate NRP2 expression through sponging miR-149-5p. Moreover, miR-149-5p overexpression abolished PDGF-BB-triggered enhancement of cell proliferation, migration, and invasion by targeting NRP2. Circ_CHFR promoted the proliferation, invasion, and migration of PDGF-BB-induced HVSMCs through miR-149-5p/NRP2 axis, providing a new insight into the pathogenesis of AS and a potential therapeutic target for AS treatment.

Circ_0002984 Enhances Growth, Invasion, and Migration in PDGF-bb-Induced Vascular Smooth Muscle Cells Through miR-379-5p/FRS2 Axis

ABSTRACT

The accumulation of vascular smooth muscle cells (VSMCs) is considered to play important roles in atherosclerosis (AS) development and progression. Circ_0002984 was found to be increased in oxidized low-density lipoprotein (ox-LDL) human VSMCs (HVSMCs). However, the function and mechanism of circ_0002984 in VSMC dysfunction remain unknown. In this study, the expression of circ_0002984, microRNA (miR)-379-5p, and fibroblast growth factor receptor substrate 2 (FRS2) was detected using quantitative real-time polymerase chain reaction and western blot. Cell proliferation, cell cycle, migration, and invasion were detected using Cell Counting Kit-8, flow cytometry, and transwell assays. The binding interaction between miR-379-5p and circ_0002984 or FRS2 was confirmed by the dual-luciferase reporter assay. Collectively, this study found that circ_0002984 was elevated in platelet-derived growth factor type bb (PDGF-bb)-induced HVSMCs. Circ_0002984 knockdown abrogated PDGF-bb-induced proliferation, migration, and invasion in HVSMCs. Mechanistically, circ_0002984 was confirmed to target miR-379-5p, and miR-379-5p upregulation reversed the protective effects of circ_0002984 knockdown on PDGF-bb-induced HVSMCs. Besides, when FRS2 was a target of miR-379-5p, miR-379-5p restoration abolished PDGF-bb-evoked HVSMC dysfunction, which was attenuated by the overexpression of FRS2. Moreover, circ_0002984 could regulate FRS2 expression through sponging miR-379-5p in HVSMCs. Collectively, these results demonstrated that circ_0002984 promoted PDGF-bb-induced VSMC proliferation, migration, and invasion through the regulation of miR-379-5p/FRS2 axis, suggesting a new insight into the pathogenesis of AS and the potential application of circ_0002984 in AS treatment.

LncRNA SNHG12 regulates ox-LDL-induced endothelial cell injury by the miR-218-5p/IGF2 axis in atherosclerosis

Atherosclerosis (AS) is a cardiovascular disorder accompanied by endothelial dysfunction. Extensive evidence demonstrates the regulatory functions of long noncoding RNAs (lncRNAs) in cardiovascular disease, including AS. Here, the function of lncRNA small nucleolar RNA host gene 12 (SNHG12) in AS progression was investigated. A cell model of AS was established in human umbilical endothelial cells (HUVECs) using oxidative low-density lipoprotein (ox-LDL). CCK-8, flow cytometry, TUNEL, ELISA, and western blotting analyses were performed. Apolipoprotein E-deficient (apoE-/-) mice fed a Western diet were used as in vivo models of AS. RT-qPCR determined the levels of SNHG12, microRNA-218-5p (miR-218-5p) and insulin-like growth factor-II (IGF2). The molecular mechanisms were investigated using luciferase reporter and RNA pull-down assays. We found that SNHG12 and IGF2 expression levels were high and miR-218-5p expression levels were low in AS patients and ox-LDL-treated HUVECs. SNHG12 depletion attenuated ox-LDL-induced injury in HUVECs, whereas miR-218-5p suppression partially abated this effect. Moreover, IGF2 overexpression prevented the alleviative role of miR-218-5p in ox-LDL-treated HUVECs. SNHG12 upregulated IGF2 expression by sponging miR-218-5p. More importantly, SNHG12 increased proinflammatory cytokine production and augmented atherosclerotic lesions in vivo. Overall, SNHG12 promotes the development of AS by the miR-218-5p/IGF2 axis.

Birth Size as a Determinant of Cardiometabolic Risk Factors in Children

The association between birth size and cardiometabolic disease risk may be U-shaped. Being born small for gestational age (SGA) has a definitive association with later cardiovascular risk, but the impact of being born large for gestational age (LGA) on cardiometabolic health is more controversial. In addition to birth size, early postnatal growth pattern and later weight gain affect cardiometabolic risk in adulthood. Most SGA-born children have catch-up and LGA-born children have catch-down growth during the first years of life. The extent of this early compensatory growth may contribute to the adverse health outcomes. Both SGA- and LGA-born children are at an increased risk for overweight and obesity. This may have a long-term impact on cardiometabolic health as overweight tends to track to adulthood. Other cardiometabolic risk factors, including alterations in glucose metabolism, dyslipidemia, hypertension, and low-grade inflammation are associated with birth weight. Many of these risk factors are related to overweight or adverse fat distribution. Since later cardiometabolic risk is often mediated by early growth pattern and later overweight in SGA and LGA children, it is important to focus on staying normal weight throughout life. Hence, effective interventions to reduce cardiometabolic risk in LGA and SGA children should be developed.

LncRNA MIAT Mediates ox-LDL-Induced Endothelial Cell Injury Via miR-206/RAB22A Axis

BACKGROUND

Long non-coding RNA myocardial infarction associated transcript (MIAT) has exerted significant effects on atherosclerosis (AS). The biological roles of MIAT in endothelial cell dysfunction are not thoroughly elucidated.

METHODS

The expression of MIAT, microRNA (miR)-206 and Ras-related protein Rab-22A (RAB22A) was detected by quantitative real-time polymerase chain reaction and western blot. The injury of human umbilical vein endothelial cells (HUVECs) was evaluated by testing cell viability, invasion, migration, apoptosis, epithelial-mesenchymal transition capacities and inflammatory response using cell counting kit-8, transwell, wound healing assays, flow cytometry, western blot and enzyme-linked immunosorbent assay, respectively. The binding interaction between miR-206 and MIAT or RAB22A was confirmed by dual-luciferase reporter and RNA immunoprecipitation assays.

RESULTS

The expression of MIAT was up-regulated in ox-LDL-treated HUVECs, and knockdown of MIAT in ox-LDL-treated HUVECs remarkably promoted cell viability, invasion, migration, and epithelial-mesenchymal transition (EMT), as well as suppressed cell apoptosis and the levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α and endothelial nitric oxide synthase (eNOS). In a mechanical study, MIAT directly targeted miR-206, and miR-206 inhibition attenuated the protective effects of MIAT knockdown on ox-LDL-triggered HUVEC injury. Besides that, RAB22A was a target of miR-206, and RAB22A overexpression reversed the biological effects of miR-206 on ox-LDL-treated HUVECs. Additionally, we also proved MIAT could regulate RAB22A via miR-206 in HUVECs.

CONCLUSION

MIAT knockdown impaired ox-LDL-induced HUVEC injury via regulating miR-206/RAB22A axis, suggesting the potential impacts of MIAT on AS occurrence, which revealed a potential therapeutic strategy for future clinic intervention in AS.

Circ_GRN Promotes the Proliferation, Migration, and Inflammation of Vascular Smooth Muscle Cells in Atherosclerosis Through miR-214-3p/FOXO1 Axis

ABSTRACT

Dysfunction of vascular smooth muscle cells (VSMCs) assumes a fundamental part in the pathogenesis of atherosclerosis (AS). Circular RNA granulin precursor (circ_GRN) was identified to promote the proliferation and invasion of human VSMCs (HVSMCs) in an in vitro AS model. However, the underlying mechanisms remain unclear. Levels of circ_GRN, microRNA (miR)-214-3p, and forkhead box protein O1 (FOXO1) were detected using quantitative real-time polymerase chain reaction and Western blot assays. The proliferation, migration, and inflammatory response of HVSMCs were evaluated by using flow cytometry, colony formation, Cell Counting Kit-8, Western blot, transwell assays, and enzyme-linked immunosorbent assay, respectively. The binding interaction between miR-214-3p and circ_GRN or FOXO1 was detected by dual-luciferase reporter assay. In this study, we found that circ_GRN was elevated in the serum of AS and oxidized low-density lipoprotein (ox-LDL)-induced HVSMCs. The in vitro AS model was established by exposing HVSMCs to ox-LDL, and we found circ_GRN knockdown reversed ox-LDL-evoked cell proliferation, migration, and inflammation. In a mechanical study, miR-214-3p directly bound to circ_GRN or FOXO1, and circ_GRN could regulate FOXO1 expression by competitively binding to miR-214-3p. Importantly, we demonstrated that miR-214-3p inhibition attenuated the protective effects of circ_GRN knockdown on ox-LDL-induced HVSMCs; besides that, miR-214-3p overexpression abolished ox-LDL-triggered HVSMC proliferation, migration, and inflammation, which were counteracted by FOXO1 upregulation. In conclusion, circ_GRN promoted the proliferation, migration, and inflammation of HVSMCs through miR-214-3p/FOXO1 axis in ox-LDL-induced AS model in vitro, suggesting the potential involvement in an AS process, which provided a potential candidate for future clinic intervention in AS.

Melatonin inhibits vascular endothelial cell pyroptosis by improving mitochondrial function via up-regulation and demethylation of UQCRC1

Atherosclerosis (AS) is a chronic inflammatory disease that involves cell death and endothelial dysfunction. Melatonin is an endocrine hormone with anti-inflammatory and anti-AS effects. However, the underlying molecular mechanisms for the anti-AS effects of melatonin are unknown. A previous study has shown that pyroptosis plays a detrimental role in the development of AS, therefore, this study was designed to investigate the anti-pyroptotic effects and potential mechanisms of melatonin in atherosclerotic endothelium. Our results show that melatonin attenuated the expression of genes related to pyroptosis, including NLRP3, caspase-1, and IL-1β, in human umbilical vein endothelial cells treated with oxidized low-density lipoprotein. Furthermore, melatonin up-regulated the expression of ten-eleven translocation 2 (TET2), inhibited the methylation of ubiquinol-cytochrome c reductase core protein 1 (UQCRC1), and reduced pyroptosis. The up-regulation of UQCRC1 by melatonin improved mitochondrial function, thereby inhibiting oxidative stress and endothelial cell pyroptosis. Collectively, our results indicate that melatonin prevents endothelial cell pyroptosis by up-regulating TET2 to inhibit the methylation of UQCRC1 and improving mitochondrial function.

Clinical Application of Melatonin in the Treatment of Cardiovascular Diseases: Current Evidence and New Insights into the Cardioprotective and Cardiotherapeutic Properties

Cardiovascular diseases (CVDs) are the leading global cause of mortality and disability, tending to happen in younger individuals in developed countries. Despite improvements in medical treatments, the therapy and long-term prognosis of CVDs such as myocardial ischemia-reperfusion, atherosclerosis, heart failure, cardiac hypertrophy and remodeling, cardiomyopathy, coronary artery disease, myocardial infarction, and other CVDs threatening human life are not satisfactory enough. Therefore, many researchers are attempting to identify novel potential therapeutic methods for the treatment of CVDs. Melatonin is an anti-inflammatory and antioxidant agent with a wide range of therapeutic properties. Recently, several investigations have been carried out to evaluate its effectiveness and efficiency in CVDs therapy, focusing on mechanistic pathways. Herein, this review aims to summarize current findings of melatonin treatment for CVDs.

FGF21 mitigates atherosclerosis via inhibition of NLRP3 inflammasome-mediated vascular endothelial cells pyroptosis

Fibroblast growth factor 21(FGF21) is an endocrine cytokine that targets inflammation and atherosclerosis (AS). However, the underlying molecular mechanisms of the FGF21 anti-AS effect remain to be explored. Pyroptosis induced by hyperlipidemia or oxidized low-density lipoprotein (oxLDL) in vascular endothelial cells (VECs) is a significant step in the advancement of AS. This work aimed to evaluate the mechanisms and functioning of FGF21 against AS using an atherosclerotic animal model and oxLDL mimic in vitro. We found that exogenous treatments with FGF21 significantly reduced the aortic sinus plaque area and ameliorated dyslipidemia in apoE^-/- mice. FGF21 attenuated the expression of pyroptosis-related proteins both in vivo and in vitro. Possibly, FGF21 improves mitochondrial function, inhibits mitochondrial division, and reduces ROS production by maintaining mitochondrial dynamics and function to reduce NLRP3 related pyroptosis and inhibits VECs endoplasmic reticulum stress, thereby exerting an anti-atherosclerotic effect.

Inhibition of the ox-LDL-Induced Pyroptosis by FGF21 of Human Umbilical Vein Endothelial Cells Through the TET2-UQCRC1-ROS Pathway

Fibroblast growth factor 21 (FGF21) is a hormone-like member of the FGF family that is associated with cell death in atherosclerosis. However, its underlying mechanisms remain unclear. In this study, the effect of FGF21 on endothelial cell pyroptosis and its potential mechanisms were investigated. Results showed that FGF21 inhibits oxidized low-density lipoprotein (ox-LDL)-induced pyroptosis and related molecular expression in human umbilical vein endothelial cells (HUVECs). Mitochondrial function was damaged by ox-LDL and restored by FGF21. A mechanism proved that ubiquinol cytochrome c reductase core protein I (UQCRC1) was downregulated by ox-LDL and upregulated by FGF21. Further, the silencing of UQCRC1 aggravated HUVEC pyroptosis and impaired mitochondrial function and reactive oxygen species (ROS) production. Moreover, Tet methylcytosine dioxygenase (TET2) was involved in the regulation of UQCRC1 expression and pyroptosis. In summary, FGF21 inhibited ox-LDL-induced HUVEC pyroptosis through the TET2-UQCRC1-ROS pathway.

Klotho protein inhibits H2O2-induced oxidative injury in endothelial cells via regulation of PI3K/AKT/Nrf2/HO-1 pathways

Klotho protein secreted in the blood could act as a hormone to regulate various target organs and have a protective effect on the cardiovascular system. Numerous studies had shown that Klotho protein had antioxidative stress, anti-inflammatory, and antiapoptotic effects on vascular endothelial cells. The purpose of this study was to investigate the protective mechanism of Klotho protein on oxidative damage of vascular endothelial cells induced by H₂O₂. Klotho protein significantly enhanced human umbilical vein endothelial cells viability and increased the activities of antioxidant enzymes (superoxide dismutase, catalase, and heme oxygenase-1 (HO-1)), scavenged reactive oxygen species, and inhibited tumor necrosis factor alpha and interleukin 6 secretion. Klotho protein also reduced the rate of apoptosis of cells and improved the function of vascular endothelial cells (increased nitric oxide secretion). Klotho protein activated nuclear translocation of Nrf2 and increased HO-1 expression. Klotho protein also activated phosphorylation of protein kinase B (AKT), whereas the addition of LY294002, a pharmacological inhibitor of phosphatidylinositol 3-kinase (PI3K), blocked Klotho-protein-induced Nrf2/HO-1 activation and cytoprotection. Klotho protein enhanced the antioxidant defense ability of the cells by activating the PI3K/AKT pathway, which upregulated the expression of Nrf2/HO-1, thereby inhibiting H₂O₂-induced oxidative damage.

Role of pyroptosis in cardiovascular disease

Cardiac function is determined by the dynamic equilibrium of various cell types and the extracellular matrix that composes the heart. Cardiovascular diseases (CVDs), especially atherosclerosis and myocardial infarction, are often accompanied by cell death and acute/chronic inflammatory reactions. Caspase‐dependent pyroptosis is characterized by the activation of pathways leading to the activation of NOD‐like receptors, especially the NLRP3 inflammasome and its downstream effector inflammatory factors interleukin (IL)‐1β and IL‐18. Many studies in the past decade have investigated the role of pyroptosis in CVDs. The findings of these studies have led to the development of therapeutic approaches based on the regulation of pyroptosis, and some of these approaches are in clinical trials. This review summarizes the molecular mechanisms, regulation and cellular effects of pyroptosis briefly and then discusses the current pyroptosis studies in CVD research.

OxLDL induces vascular endothelial cell pyroptosis through miR-125a-5p/TET2 pathway

Pyroptosis participates in the formation and development of atherosclerosis (As) by promoting inflammatory factor release and is closely related to the stability of atherosclerotic plaque. MicroRNAs can regulate the expression of target genes at the posttranscriptional level. Previous studies have shown that miR-125a-5p increases in hyperlipidemic-hyperglycemic conditions and is involved in apoptosis, but its specific role in pyroptosis and As remains unclear. We propose that miR-125a-5p may be implicated in oxidized low-density lipoprotein (oxLDL)-induced vascular endothelial cells (VECs) pyroptosis and therefore conducted the current study. We observed that miR-125a-5p can inhibit tet methylcytosine dioxygenase 2 (TET2) expression at the posttranscription level, resulting in abnormal DNA methylation, mitochondrial dysfunction, and increased reactive oxygen species production, activated nuclear factor-κB that induces activation of inflammasome and maturation, release of proinflammatory cytokines interleukin (IL)-1β and IL-18, and pyroptosis. Given the role of VECs in vascular physiology, oxLDL-induced VEC pyroptosis may promote the development of As. Our current study reveals a novel pathway associated with pyroptosis program regulation, which comprises miR-125a-5p and TET2 in VECs. Modulation of their expression levels may serve as a potential target for therapeutic strategies of As.

Knockdown of long noncoding RNA XIST alleviates oxidative low-density lipoprotein-mediated endothelial cells injury through modulation of miR-320/NOD2 axis

Atherosclerosis remains to be one of the most common vascular disorders resulting in morbidity and mortality in the world. Recent studies suggested that endothelial cells (ECs) injury caused by oxidative low-density lipoprotein (ox-LDL) is an early marker for atherosclerosis. Nevertheless, the mechanisms of ox-LDL-induced ECs injury are complicated and largely unknown. Here, we found lncRNA XIST (X-inactive specific transcript) was upregulated in human umbilical vein endothelial cells (HUVECs) stimulated by ox-LDL. Knockdown of XIST boosted the cell viability and suppressed cell apoptosis under ox-LDL stimuli. Further experiments identified XIST regulated the expression of Nucleotide-Binding Oligomerization Domain 2 (NOD2) by sponging miR-320. XIST silencing exerted a protective effect on ox-LDL-induced HUVECs injury via miR-320/NOD2 regulatory network. Our data provide insight into the role of the lncRNA XIST in ox-LDL mediated ECs injury, which can aid in developing new therapeutic strategies for the treatment of atherosclerosis.

Adenosine 5'-Triphosphate Metabolism in Red Blood Cells as a Potential Biomarker for Post-Exercise Hypotension and a Drug Target for Cardiovascular Protection

The importance of adenosine and ATP in regulating many biological functions has long been recognized, especially for their effects on the cardiovascular system, which may be used for management of hypertension and cardiometabolic diseases. In response to ischemia and cardiovascular injury, ATP is broken down to release adenosine. The effect of adenosine is very short lived because it is rapidly taken up by erythrocytes (RBCs), myocardial and endothelial cells, and also rapidly catabolized to oxypurine metabolites. Intracellular adenosine is phosphorylated back to adenine nucleotides via a salvage pathway. Extracellular and intracellular ATP is broken down rapidly to ADP and AMP, and finally to adenosine by 5′-nucleotidase. These metabolic events are known to occur in the myocardium, endothelium as well as in RBCs. Exercise has been shown to increase metabolism of ATP in RBCs, which may be an important mechanism for post-exercise hypotension and cardiovascular protection. The post-exercise effect was greater in hypertensive than in normotensive rats. The review summarizes current evidence in support of ATP metabolism in the RBC as a potential surrogate biomarker for cardiovascular protection and toxicities. It also discusses the opportunities, challenges, and obstacles of exploiting ATP metabolism in RBCs as a target for drug development and precision medicine.

Melatonin prevents endothelial cell pyroptosis via regulation of long noncoding RNA MEG3/miR-223/NLRP3 axis

Atherosclerosis (AS) is an inflammatory disease linked to endothelial dysfunction. Melatonin is reported to possess substantial anti-inflammatory properties, which has proven to be effective in AS. Emerging literature suggests that pyroptosis plays a critical role during AS progression. However, whether pyroptosis contributes to endothelial dysfunction and the underlying molecular mechanisms remained unexploited. This study was designed to investigate the antipyroptotic effects of melatonin in atherosclerotic endothelium and to elucidate the potential mechanisms. In this study, high-fat diet (HFD)-treated ApoE^-/- mice were used as an atherosclerotic animal model. We found intragastric administration of melatonin for 12 weeks markedly reduced the atherosclerotic plaque in aorta. Meanwhile, melatonin also attenuated the expression of pyroptosis-related genes, including NLRP3, ASC, cleaved caspase1, NF-κB/GSDMD, GSDMD N-termini, IL-1β, and IL-18 in aortic endothelium of melatonin-treated animals. Consistent antipyroptotic effects were also observed in ox-LDL-treated human aortic endothelial cells (HAECs). We found that lncRNA MEG3 enhanced pyroptosis in HAECs. Moreover, MEG3 acted as an endogenous sponge by sequence complementarity to suppress the function of miR-223 and to increase NLRP3 expression and enhance endothelial cell pyroptosis. Furthermore, knockdown of miR-223 blocked the antipyroptotic actions of melatonin in ox-LDL-treated HAECs. Together, our results suggest that melatonin prevents endothelial cell pyroptosis via MEG3/miR-223/NLRP3 axis in atherosclerosis, and therefore, melatonin replacement might be considered a new strategy for protecting endothelium against pyroptosis, thereby for the treatment of atherosclerosis associated with pyroptosis.

Plasma IL-1 Receptor Antagonist Concentration Has an Inverse Association With Birth Weight in Prepubertal Children

Context:

Birth size has an impact on later cardiometabolic risk that is strongly related to low-grade inflammation.

Objective:

To evaluate plasma interleukin-1 receptor antagonist (IL-1ra) concentrations in relation to birth size and cardiometabolic and inflammatory markers in prepubertal children.

Design:

A cohort study. Anthropometric data were recorded. Fasting blood samples were collected for plasma analyses of IL-1ra, alanine transaminase, total cholesterol, high- and low-density lipoprotein cholesterols, triglyceride, glucose, and serum analyses of 25-hydroxyvitamin D [25(OH)D] and high-sensitivity C-reactive protein (hs-CRP) concentrations.

Participants:

Forty-nine large for gestational age (LGA), 56 appropriate for gestational age, and 23 small for gestational age (SGA) children at 5 to 8 years of age were examined.

Main Outcome Measures:

Differences in IL-1ra concentrations among the birth-size groups and associations between IL-1ra and other metabolic markers were assessed.

Results:

Body mass index (BMI) standard deviation score (SDS)-adjusted plasma IL-1ra concentrations were highest in the SGA- and lowest in the LGA-born children (P = 0.015). Age- and sex-adjusted IL-1ra concentrations had strongest associations with BMI SDS (P < 0.001) and hs-CRP (P < 0.001, also when further adjusted for BMI SDS).

Conclusions:

Prepubertal children born SGA had the highest and those born LGA the lowest IL-1ra concentrations in this study cohort. Most associations found between IL-1ra and the studied metabolic parameters were weight related, but the association with hs-CRP remained strong after adjustment for BMI. It seems that at prepuberty, SGA children have a stronger inflammatory state than LGA children and may thus be at a greater risk for later metabolic disturbances.

Polyphenols and Oxidative Stress in Atherosclerosis-Related Ischemic Heart Disease and Stroke

Good nutrition could maintain health and life. Polyphenols are common nutrient mainly derived from fruits, vegetables, tea, coffee, cocoa, mushrooms, beverages, and traditional medicinal herbs. They are potential substances against oxidative-related diseases, for example, cardiovascular disease, specifically, atherosclerosis-related ischemic heart disease and stroke, which are health and economic problems recognized worldwide. In this study, we reviewed the risk factors for atherosclerosis, including hypertension, diabetes mellitus, hyperlipidemia, obesity, and cigarette smoking as well as the antioxidative activity of polyphenols, which could prevent the pathology of atherosclerosis, including endothelial dysfunction, low-density lipoprotein oxidation, vascular smooth muscle cell proliferation, inflammatory process by monocytes, macrophages or T lymphocytes, and platelet aggregation. The strong radical-scavenging properties of polyphenols would exhibit antioxidative and anti-inflammation effects. Polyphenols reduce ROS production by inhibiting oxidases, reducing the production of superoxide, inhibiting OxLDL formation, suppressing VSMC proliferation and migration, reducing platelet aggregation, and improving mitochondrial oxidative stress. Polyphenol consumption also inhibits the development of hypertension, diabetes mellitus, hyperlipidemia, and obesity. Despite the numerous in vivo and in vitro studies, more advanced clinical trials are necessary to confirm the efficacy of polyphenols in the treatment of atherosclerosis-related vascular diseases.

Clinical predictors of the estimated glomerular filtration rate 1 year after radical nephrectomy in Japanese patients

Purpose

To evaluate renal function 1 year after radical nephrectomy (RN) for renal cell carcinoma, the preoperative predictors of postnephrectomy renal function were investigated by sex, and equations to predict the estimated glomerular filtration rate (eGFR) 1 year after RN were developed.

Materials and Methods

A total of 525 patients who underwent RN between May 2007 and August 2011 at Tohoku University Hospital and its affiliated hospitals were prospectively evaluated. Overall, 422 patients were analyzed in this study.

Results

Independent preoperative factors associated with postnephrectomy renal function were different in males and females. Preoperative eGFR, age, tumor size, and body mass index (BMI) were independent factors in males, while tumor size and BMI were not independent factors in females. The equations developed to predict eGFR 1 year after RN were: Predicted eGFR in males (mL/min/1.73 m²)=27.99−(0.196×age)+(0.497×eGFR)+(0.744×tumor size)−(0.339×BMI); and predicted eGFR in females=44.57−(0.275×age)+(0.298×eGFR). The equations were validated in the validation dataset (R²=0.63, p<0.0001 and R²=0.31, p<0.0001, respectively).

Conclusions

The developed equations by sex enable better prediction of eGFR 1 year after RN. The equations will be useful for preoperative patient counseling and selection of the type of surgical procedure in elective partial or RN cases.

Medium-chain fatty acids reduce serum cholesterol by regulating the metabolism of bile acid in C57BL/6J mice

Hypercholesterolemia is one of the important risk factors of atherosclerosis (AS).

Pathological interactions between the endothelin-1 and the angiotensin- converting enzyme among Tunisian coronary patients

Background

The correct understanding of the biochemical and metabolic interactions between coronary risk factors contribute to the exploration of cardiovascular pathophysiology and improves therapeutic care.

The aim of this study was to explore the endothelin-1 (ET-1) concentration and the angiotensin converting enzyme (ACE) activity among Tunisian patients with coronary heart disease, and to investigate the metabolic relationships between these two markers,… and to assess the possible relationship between them and the different risk factors.

In this present study, ET-1 concentration was determined by an analytical method (High Performance Chromatography, coupled by Mass Spectrometry), ACE activity was measured by a kinetic method for patients and healthy controls. These subjects (157 patients and 142 controls) beneficed also by a biochemical exploration (lipid, apolipoproteins and glucose profiles) to quantify cardiovascular risk.

Results

A statistically significant increase of the ET-1 concentration was found among patients compared to healthy controls (15.2 ± 5.3 nM vs 7.1 ± 2.7 nM, p < 0,00001). For the ACE activity, in spite the treatment of the majority of patients (97%) with ACE inhibitors, this activity was statistically elevated in patients compared to healthy subjects (86.7 ± 25.4 IU/L vs 42.8 ± 12.1 IU/L, p < 0.00001).

Furthermore, a statistically positive correlation was identified between these two cardiac markers (r = 0.68 p < 0.00001).

Conclusion

The study of the metabolic relationship between the ET-1 and ACE among coronary patients reveals other therapeutics targets.

Myosin light chain kinase inhibitor ML7 improves vascular endothelial dysfunction via tight junction regulation in a rabbit model of atherosclerosis

Vascular endothelial dysfunction (VED) is an important factor in the initiation and development of atherosclerosis (AS). Previous studies have demonstrated that endothelial permeability is increased in diet‑induced AS. However, the precise underlying mechanisms remain poorly understood. The present study aimed to analyze whether the myosin light chain kinase (MLCK) inhibitor ML7 is able to improve VED and AS by regulating the expression of the tight junction (TJ) proteins zona occludens (ZO)‑1 and occludin via mechanisms involving MLCK and MLC phosphorylation in high‑fat diet‑fed rabbits. New Zealand white rabbits were randomly divided into three groups: Control group, AS group and ML7 group. The rabbits were fed a standard diet (control group), a high‑fat diet (AS group) or a high‑fat diet supplemented with 1 mg/kg/day ML7 (ML7 group). After 12 weeks, endothelium‑dependent relaxation and endothelium‑independent relaxation were measured using high-frequency ultrasound. Administration of a high‑fat diet significantly increased the levels of serum lipids and inflammatory markers in the rabbits in the AS group, as compared with those in the rabbits in the control group. Furthermore, a high‑fat diet contributed to the formation of a typical atherosclerotic plaque, as well as an increase in endothelial permeability and VED. These symptoms of AS were significantly improved following treatment with ML7, as demonstrated in the ML7 group. Hematoxylin & eosin and immunohistochemical staining indicated that ML7 was able to decrease the expression of MLCK and MLC phosphorylation in the arterial wall of rabbits fed a high‑fat diet. A similar change was observed for the TJ proteins ZO‑1 and occludin. In addition, western blot analysis demonstrated that ML7 increased the expression levels of occludin in the precipitate, but reduced its expression in the supernatant of lysed aortas. These results indicated that occludin, which is a dynamic protein at the TJ, is associated with remodeling from cell membrane to cytoplasm. The present study was the first, to the best of our knowledge, to indicate that ML7 may ameliorate VED and AS by regulating the TJ proteins ZO‑1 and occludin via mechanisms involving MLCK and MLC phosphorylation.

Computed tomography imaging of early coronary artery lesions in stable individuals with multiple cardiovascular risk factors

OBJECTIVES

To investigate the prevalence, extent, severity, and features of coronary artery lesions in stable patients with multiple cardiovascular risk factors.

METHODS

Seventy-seven patients with more than 3 cardiovascular risk factors were suspected of having coronary artery disease. Patients with high-risk factors and 39 controls with no risk factors were enrolled in the study. The related risk factors included hypertension, impaired glucose tolerance, dyslipidemia, smoking history, and overweight. The characteristics of coronary lesions were identified and evaluated by 64-slice coronary computed tomography angiography.

RESULTS

The incidence of coronary atherosclerosis was higher in the high-risk group than in the no-risk group. The involved branches of the coronary artery, the diffusivity of the lesion, the degree of stenosis, and the nature of the plaques were significantly more severe in the high-risk group compared with the no-risk group (all p < 0.05).

CONCLUSION

Among stable individuals with high-risk factors, early coronary artery lesions are common and severe. Computed tomography has promising value for the early screening of coronary lesions.

New aspects on the metabolic role of intestinal microbiota in the development of atherosclerosis

Gut microbiota remains a very interesting, yet largely unexplored ecosystem inside the human organism. The importance of this ecosystem for the physiology and the pathophysiology of the organism is being slowly unraveled. Recent studies reveal a connection between intestinal microbiota and atherosclerosis development. It seems that alterations in the function and composition of this bacterial population lead through complex mechanisms to a high risk for atherosclerosis. Although these mechanisms remain largely unknown, published studies show that microbiota can lead to atherosclerosis either by augmenting known risk factors or via other, more "direct" mechanisms. This review article summarizes the available literature regarding this matter.

Nonalcoholic fatty liver disease as a potential risk factor of cardiovascular disease

Nonalcoholic fatty liver disease (NAFLD) is the hepatic component of the metabolic syndrome. The aim of this review is to summarize the available data linking NAFLD with cardiovascular disease (CVD). The following topics are reviewed: (a) the clinical evidence linking NAFLD to increased prevalence of CVD; (b) the relationship between NAFLD (which is diagnosed by liver biopsy, serum liver enzymes, or ultrasonography) and incidence of CVD; (c) the mechanism linking NAFLD to CVD and clinical implication; and (d) the potential impact of NAFLD treatment on cardiac complications. CVD dictates the outcome (or outcomes) in patients with NAFLD more frequently and to a greater extent than does the progression of liver disease. NAFLD patients have a higher risk of all-cause death than the general population, mainly because of CVD or liver-related causes. The biologic mechanism linking NAFLD and CVD might be associated with various factors, involving a complex interaction among insulin resistance, oxidative stress, abnormal adipocytokine profile, endothelial dysfunction, lipid abnormalities, and activation of inflammatory cascade. Lifestyle modifications and pharmacotherapy are helpful to treat patients with NAFLD. NAFLD is likely to be associated with an increased risk of CVD, and raises the possibility that NAFLD may not only be a marker but also an early mediator of CVD.

[High sensitivity C protein as an independent risk factor in people with and without history of cardiovascular disease]

Among the new cardiovascular event (CVE) risk biomarkers, C-reactive protein detected using high sensitive techniques (hs-CRP) has been one of the most commonly evaluated. In this review, the available evidence on the usefulness of hs-CRP was explored as an independent risk event factor in subjects with no cardiovascular history and as prognosis in case of chronic or acute cardiovascular condition. An overview (revision of revisions) was carried out searching in the main bibliographic databases and in other general Internet search engines. During the first stage, systematic reviews, clinical practice guidelines, health technology assessments and coverage policies were found and, during the second stage primary studies published after the systematic review search dates were added. Seven hundred and seventy four quotes were found, including 36 papers assessing the role of hs-CRP in healthy populations or with cardiovascular history. High quality evidence was found pointing out hs-CRP, both as risk factor in the general population and as prognostic factor in those with CVE, in all the populations assessed. It was most useful in subjects with a history of CVE and intermediate risk of events at 10 years; where adding hs-CRP to the classical models for event risk estimation improves risk staging. There was no consensus on its clinical usefulness as a prognostic marker in subjects with chronic or acute disease.

An association study between genetic polymorphism in the interleukin-6 receptor gene and coronary heart disease

The goal of our study is to test the association of IL6R rs7529229 polymorphism with CHD through a case-control study in Han Chinese population and a meta-analysis. Our result showed there is a lack of association between IL6R rs7529229 polymorphism and CHD on both genotype and allele levels in Han Chinese (P > 0.05). However, a meta-analysis among 11678 cases and 12861 controls showed that rs7529229-C allele was significantly associated with a decreased risk of CHD, especially in Europeans (P < 0.0001, odds ratio = 0.93, 95% confidential interval = 0.89–0.96). Since there is significant difference among different populations, further studies are warranted to test the contribution of rs7529229 to CHD in other ethnic populations.

Plasma paraoxonase and arylesterase activities in smokers and smokeless tobacco users as Maraş powder

CONTEXT

Maraş powder (MP), a different type of smokeless tobacco (ST) prepared from a tobacco called Nicotiana rustica Linn, is widely used in the Southern Turkey. Smoking and ST cause oxidative stress (OS) in the human body. Paraoxonase (PON) and arylesterase (ARE) are antioxidant enzymes.

OBJECTIVE

To investigate the effects of MP on activities of PON, ARE, and malondialdehyde (MDA) levels in plasma and to compare these parameters in smokers and MP users (MPU).

MATERIALS AND METHODS

The study consisted of smokers, MPU, and control group (CG) neither smoking nor using MP healthy subjects. PON and ARE activities were measured spectrophotometrically using paraoxon and phenylacetate substrates, respectively.

RESULTS

PON and ARE activities were decreased whereas MDA levels were increased in tobacco groups compared to the CG. The differences of ARE and MDA values between the tobacco groups and CG were found statistically significant (p < 0.01). But no significant differences were detected between the groups in the activity of PON (p > 0.05). However, the lowest activities of the enzymes were obtained in MPU.

CONCLUSION

Our results can help to evaluate harmful effects of cigarette and ST as MP. These effects can be attributed to increased OS. Increased plasma MDA levels and decreased ARE activities may be important in assessing oxidant/antioxidant imbalance in MPU as well as smokers. Also, using of MP has harmful effects at least cigarette smoking.

Risk of cardiovascular, cardiac and arrhythmic complications in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has emerged as a public health problem of epidemic proportions worldwide. Accumulating clinical and epidemiological evidence indicates that NAFLD is not only associated with liver-related morbidity and mortality but also with an increased risk of coronary heart disease (CHD), abnormalities of cardiac function and structure (e.g., left ventricular dysfunction and hypertrophy, and heart failure), valvular heart disease (e.g., aortic valve sclerosis) and arrhythmias (e.g., atrial fibrillation). Experimental evidence suggests that NAFLD itself, especially in its more severe forms, exacerbates systemic/hepatic insulin resistance, causes atherogenic dyslipidemia, and releases a variety of pro-inflammatory, pro-coagulant and pro-fibrogenic mediators that may play important roles in the pathophysiology of cardiac and arrhythmic complications. Collectively, these findings suggest that patients with NAFLD may benefit from more intensive surveillance and early treatment interventions to decrease the risk for CHD and other cardiac/arrhythmic complications. The purpose of this clinical review is to summarize the rapidly expanding body of evidence that supports a strong association between NAFLD and cardiovascular, cardiac and arrhythmic complications, to briefly examine the putative biological mechanisms underlying this association, and to discuss some of the current treatment options that may influence both NAFLD and its related cardiac and arrhythmic complications.

High-density lipoprotein maintains skeletal muscle function by modulating cellular respiration in mice

BACKGROUND

Abnormal glucose metabolism is a central feature of disorders with increased rates of cardiovascular disease. Low levels of high-density lipoprotein (HDL) are a key predictor for cardiovascular disease. We used genetic mouse models with increased HDL levels (apolipoprotein A-I transgenic [apoA-I tg]) and reduced HDL levels (apoA-I-deficient [apoA-I ko]) to investigate whether HDL modulates mitochondrial bioenergetics in skeletal muscle.

METHODS AND RESULTS

ApoA-I ko mice exhibited fasting hyperglycemia and impaired glucose tolerance test compared with wild-type mice. Mitochondria isolated from gastrocnemius muscle of apoA-I ko mice displayed markedly blunted ATP synthesis. Endurance capacity during exercise exhaustion test was impaired in apoA-I ko mice. HDL directly enhanced glucose oxidation by increasing glycolysis and mitochondrial respiration rate in C2C12 muscle cells. ApoA-I tg mice exhibited lower fasting glucose levels, improved glucose tolerance test, increased lactate levels, reduced fat mass, associated with protection against age-induced decline of endurance capacity compared with wild-type mice. Circulating levels of fibroblast growth factor 21, a novel biomarker for mitochondrial respiratory chain deficiencies and inhibitor of white adipose lipolysis, were significantly reduced in apoA-I tg mice. Consistent with an increase in glucose utilization of skeletal muscle, genetically increased HDL and apoA-I levels in mice prevented high-fat diet-induced impairment of glucose homeostasis.

CONCLUSIONS

In view of impaired mitochondrial function and decreased HDL levels in type 2 diabetes mellitus, our findings indicate that HDL-raising therapies may preserve muscle mitochondrial function and address key aspects of type 2 diabetes mellitus beyond cardiovascular disease.

Melatonin ameliorates vascular endothelial dysfunction, inflammation, and atherosclerosis by suppressing the TLR4/NF-κB system in high-fat-fed rabbits

Vascular endothelial dysfunction (VED) and inflammation contribute to the initiation and progression of atherosclerosis. Melatonin (MLT) normalizes lipid profile, improves endothelial function, and possesses anti-inflammatory properties. However, the precise mechanisms are still unclear. This study investigated whether MLT could ameliorate VED, inflammation, and atherosclerosis by suppressing the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) system in high-fat-fed rabbits. Rabbits were randomly divided into three groups that received a standard diet (control group), high-cholesterol diet (atherosclerosis group), or high-cholesterol diet plus 10 mg/kg/day MLT (MLT group) for 12 wk. After treatment, high-fat diet significantly increased serum lipid and inflammatory markers in rabbits in atherosclerosis group compared with that in control group. In addition, high-fat diet also induced VED and typical atherosclerotic plaque formation and increased intima/media thickness ratio, which were significantly improved by MLT therapy as demonstrated in MLT group. Histological and immunoblot analysis further showed that high-fat diet enhanced the expressions of TLR4, myeloid differentiation primary response protein (MyD88), and NF-κB p65, but decreased inhibitor of NF-κB (IκB) expression. By contrast, MLT therapy decreased the expressions of TLR4, MyD88, and NF-κB p65 and increased IκB expression. This study has demonstrated that MLT ameliorates lipid metabolism, VED, and inflammation and inhibits the progression of atherosclerosis in high-fat-fed rabbits. Moreover, our study indicates for the first time that suppression of the TLR4/NF-κB system in local vasculature with atherosclerotic damage is important for the protective effects of MLT.