Eicosapentaenoic Acid Ameliorates Cardiac Fibrosis and Tissue Inflammation in Spontaneously Hypertensive Rats

The mechanism of lncRNA PVT1 targeting the miR-30a/Beclin-1 axis to mediate ventricular remodeling in spontaneously hypertensive rats

OBJECTIVES

Hypertension poses a great health threat globally. We probed the mechanisms of long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1) mediating ventricular remodeling (VR) in spontaneously hypertensive rats (SHR).

METHODS

PVT1 was down-regulated or miR-30a was inhibited in SHR in vivo. Hypertensive injury model was established in vitro. VR, fibrosis and autophagy-related indicators were detected by echocardiography, HE/WGA/Masson staining, ELISA, and immunohistochemistry. Cell viability, fibrosis markers, autophagy-related markers, and lncRNA PVT1 and miR-30a levels were assessed. Interactions between PVT1, Beclin-1 and miR-30a were verified.

RESULTS

PVT1 was up-regulated in myocardial tissues of SHR. PVT1 knockdown alleviated VR and myocardial fibrosis (MF) in SHR, as evidenced by decreased systolic blood pressure, left ventricular end-systolic diameter, left ventricular end-systolic diameter, and heart weight index, boosted left ventricular fractional shortening and left ventricular ejection fraction, abated inflammatory infiltration of myocardial tissues, decreased myocardial hypertrophy and interstitial fibrosis, reduced serum angiotensin II (Ang II) and atrial natriuretic peptide, and downregulated collagen I, collagen II, α-smooth muscle actin, and fibronectin protein. PVT1 knockdown down-regulated Beclin 1 and LC3B-II/LC3B-I and up-regulated p62 protein. In vitro, PVT1 knockdown improved fibrosis by inhibiting Ang II-induced cardiomyocyte autophagy. PVT1 acted as a competitive endogenous RNA to competitively bind to miR-30a to target Beclin-1 expression. PVT1 targeted the miR-30a/Beclin-1 axis to mediate autophagy to affect VR and MF in SHR.

CONCLUSIONS

LncRNA PVT1 promotes cellular autophagy by targeting the miR-30a/Beclin-1 axis, thereby promoting VR and MF in SHR. Knockdown of lncRNA PVT1 attenuates VR and MF in SHR.

Eicosapentaenoic acid induces macrophage Mox polarization to prevent diabetic cardiomyopathy

Diabetic cardiomyopathy (DC) leads to heart failure, with few effective approaches for its intervention. Eicosapentaenoic acid (EPA) is an essential nutrient that benefits the cardiovascular system, but its effect on DC remains unknown. Here, we report that EPA protects against DC in streptozotocin and high-fat diet-induced diabetic mice, with an emphasis on the reduction of cardiac M1-polarized macrophages. In vitro, EPA abrogates cardiomyocyte injury induced by M1-polarized macrophages, switching macrophage phenotype from M1 to Mox, but not M2, polarization. Moreover, macrophage Mox polarization combats M1-polarized macrophage-induced cardiomyocyte injury. Further, heme oxygenase 1 (HO-1) was identified to maintain the Mox phenotype, mediating EPA suppression of macrophage M1 polarization and the consequential cardiomyocyte injury. Mechanistic studies reveal that G-protein-coupled receptor 120 mediates the upregulation of HO-1 by EPA. Notably, EPA promotes Mox polarization in monocyte-derived macrophages from diabetic patients. The current study provides EPA and macrophage Mox polarization as novel strategies for DC intervention.

Crosstalk between macrophages and immunometabolism and their potential roles in tissue repair and regeneration

Immune metabolism is a result of many specific metabolic reactions, such as glycolysis, the tricarboxylic acid (TCA) pathway, the pentose phosphate pathway (PPP), mitochondrial oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), fatty acid biosynthesis (FAs) and amino acid pathways, which promote cell proliferation and maintenance with structural and pathological energy to regulate cellular signaling. The metabolism of macrophages produces many metabolic intermediates that play important regulatory roles in tissue repair and regeneration. The metabolic activity of proinflammatory macrophages (M1) mainly depends on glycolysis and the TCA cycle system, but anti-inflammatory macrophages (M2) have intact functions of the TCA cycle, which enhances FAO and is dependent on OXPHOS. However, the metabolic mechanisms of macrophages in tissue repair and regeneration have not been well investigated. Thus, we review how three main metabolic mechanisms of macrophages, glucose metabolism, lipid metabolism, and amino acid metabolism, regulate tissue repair and regeneration.

Triglyceride-lowering therapy for the prevention of cardiovascular events, stroke, and mortality in patients with diabetes: A meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Triglyceride (TG)-lowering therapy is efficient for the prevention of cardiovascular disease (CVD) in the general population; however, for diabetic individuals, it is more controversial. The purpose of this study was to pool the results from randomized controlled trials (RCTs) to clarify whether the lowering of TG is beneficial for the prevention of CVD events, stroke, and mortality in subjects with diabetes.

METHODS

MEDLINE, Web of Science, EMBASE, ClinicalTrials.gov, and the Cochrane Central Register for Controlled Trials were searched to identify the relevant literature. We included randomized controlled trials (RCTs) to assess the association of triglyceride-lowering therapy with the prevention of CVD events, stroke, and mortality in diabetic patients.

RESULTS

Overall, 19 studies were included in this meta-analysis. Compared with the control groups, TG lowering was associated with a decreased risk of CVD events (RR = 0.91, 95% CI 0.87-0.95, p = 0.000) and CVD mortality (RR = 0.93, 95% CI 0.86-1.00, p = 0.047). There was no significant correlation between TG-lowering therapy and the incidence of stroke and all-cause mortality (RR = 0.93, 95% CI 0.86-1.02, p = 0.129 and RR = 0.97, 95% CI 0.93-1.01, p = 0.107, respectively). Subgroup analysis showed that the decreased CVD risk resulting from TG-lowering therapy was independent of age, sex, region, duration of follow-up, degree of TG reduction and glycemic control.

CONCLUSIONS

TG-lowering therapy is associated with a reduction in CVD events and cardiovascular-specific mortality, but not in stroke and all-cause mortality. Future large, multicenter RCTs will further confirm these conclusions.

Macrophage Polarization in Left Ventricular Structural Remodeling Induced by Hypertension

Following long-term hypertension, mechanical stretching and neuroendocrine stimulation, cause multiple heterogeneous cells of the heart to interact, and result in myocardial remodeling with myocardial hypertrophy and fibrosis. The immune system, specifically macrophages, plays a vital role in this process. Macrophages are heterogeneous and plastic. Regulated by factors such as microenvironment and cytokines, polarization can be divided into two main forms: M1/M2, with different polarizations playing different roles in left ventricular structural remodeling associated with hypertension. However, descriptions of macrophage phenotypes in hypertension-induced myocardial hypertrophy models are not completely consistent. This article summarizes the phenotypes of macrophages in several models, aiming to assist researchers in studying macrophage phenotypes in hypertension-induced left ventricular structural remodeling models.

The Role of Omega-3 in Attenuating Cardiac Remodeling and Heart Failure through the Oxidative Stress and Inflammation Pathways

Cardiac remodeling is defined as molecular, cellular, and interstitial changes that manifest clinically as alterations in the size, shape, and function of the heart. Despite the pharmacological approaches, cardiac remodeling-related mortality rates remain high. Therefore, other therapeutic options are being increasingly studied. This review highlights the role of omega-3 as an adjunctive therapy to attenuate cardiac remodeling, with an emphasis on its antioxidant and anti-inflammatory actions.

Cardiac Fibrosis in heart failure: Focus on non-invasive diagnosis and emerging therapeutic strategies

Heart failure is a leading cause of mortality and hospitalization worldwide. Cardiac fibrosis, resulting from the excessive deposition of collagen fibers, is a common feature across the spectrum of conditions converging in heart failure. Eventually, either reparative or reactive in nature, in the long-term cardiac fibrosis contributes to heart failure development and progression and is associated with poor clinical outcomes. Despite this, specific cardiac antifibrotic therapies are lacking, making cardiac fibrosis an urgent unmet medical need. In this context, a better patient phenotyping is needed to characterize the heterogenous features of cardiac fibrosis to advance toward its personalized management. In this review, we will describe the different phenotypes associated with cardiac fibrosis in heart failure and we will focus on the potential usefulness of imaging techniques and circulating biomarkers for the non-invasive characterization and phenotyping of this condition and for tracking its clinical impact. We will also recapitulate the cardiac antifibrotic effects of existing heart failure and non-heart failure drugs and we will discuss potential strategies under preclinical development targeting the activation of cardiac fibroblasts at different levels, as well as targeting additional extracardiac processes.

Bioactive Compounds and Cardiac Fibrosis: Current Insight and Future Prospect

Cardiac fibrosis is a pathological condition characterized by excessive deposition of collagen and other extracellular matrix components in the heart. It is recognized as a major contributor to the development and progression of heart failure. Despite significant research efforts in characterizing and identifying key molecular mechanisms associated with myocardial fibrosis, effective treatment for this condition is still out of sight. In this regard, bioactive compounds have emerged as potential therapeutic antifibrotic agents due to their anti-inflammatory and antioxidant properties. These compounds exhibit the ability to modulate fibrogenic processes by inhibiting the production of extracellular matrix proteins involved in fibroblast to myofibroblast differentiation, or by promoting their breakdown. Extensive investigation of these bioactive compounds offers new possibilities for preventing or reducing cardiac fibrosis and its detrimental consequences. This comprehensive review aims to provide a thorough overview of the mechanisms underlying cardiac fibrosis, address the limitations of current treatment strategies, and specifically explore the potential of bioactive compounds as therapeutic interventions for the treatment and/or prevention of cardiac fibrosis.