miR-214 and miR-126 were associated with restoration of endothelial function in obesity after exercise and dietary intervention

Is It Possible to Train the Endothelium?-A Narrative Literature Review

This review provides an overview of current knowledge regarding the adaptive effects of physical training on the endothelium. The endothelium plays a crucial role in maintaining the health of vessel walls and regulating vascular tone, structure, and homeostasis. Regular exercise, known for its promotion of cardiovascular health, can enhance endothelial function through various mechanisms. The specific health benefits derived from exercise are contingent upon the type and intensity of physical training. The review examines current clinical evidence supporting exercise's protective effects on the vascular endothelium and identifies potential therapeutic targets for endothelial dysfunction. There is an urgent need to develop preventive strategies and gain a deeper understanding of the distinct impacts of exercise on the endothelium.

Acute effect of high-intensity interval exercise on vascular endothelial function and possible mechanisms of wall shear stress in young obese males

Objective: To investigate the mechanisms of wall shear stress (WSS) responsible for the effects of high-intensity interval exercise (HIIE) on vascular endothelial function in young obese males.

Methods: A within-subject study design was used. We examined the response of the reactive hyperemia index (RHI) to acute HIIE in young obese males (n = 20, age = 20.38 ± 1.40 years, body mass index [BMI] = 31.22 ± 3.57, body fat percentage [BF (%)] = 31.76 ± 3.57). WSS was manipulated using 100, 80, or 60 mmHg cuff inflation during the HIIE to determine the proper inflation capable of maintaining WSS near baseline levels. One-way repeated measures analysis of variance and LSD post hoc tests were performed to compare changes in WSS and vascular endothelial function at baseline HIIE and following HIIE using different cuff inflations.

Results: There were no significant differences in RHI and WSS between the three cuff inflation values (p > 0.05). WSS was significantly higher in obese male individuals after HIIE and HIIE with 100 mmHg cuff inflation (p = 0.018, p = 0.005) than that at baseline, with no significant differences observed comparing HIIE and HIIE with 100 mmHg inflation (p = 0.23). The RHI after HIIE was significantly higher (p = 0.012) than that at baseline, while no significant differences were detected after HIIE at 100 mmHg (p = 0.91). The RHI was significantly lower after HIIE with 100 mmHg than that after HIIE (p = 0.007). WSS (p = 0.004) and RHI (p = 0.017) were significantly higher after HIIE than that at baseline, while no significant differences were observed after HIIE with either 80 or 60 mmHg cuff inflation (baseline vs. HIIE + 80 mmHg: WSS: p = 0.33, RHI: p = 0.38; baseline vs. HIIE + 60 mmHg: WSS: p = 0.58, RHI: p = 0.45). WSS was similar to HIIE, after HIIE with either 80 or 60 mmHg inflation (p = 0.36, p = 0.40). However, RHI was significantly higher for HIIE than for HIIE with both 80 and 60 mmHg inflation (p = 0.011, p = 0.006).

Conclusion: HIIE could significantly improve WSS and vascular endothelial function. HIIE intervention with 60 or 80 mmHg inflation might enhance WSS near the baseline level. HIIE-induced acute changes in WSS may provide the primary physiological stimulus for vascular endothelial adaptation to HIIE in young obese males.

Effects of aquatic high-intensity interval training and moderate-intensity continuous training on central hemodynamic parameters, endothelial function and aerobic fitness in inactive adults

Objective

The effects of land-based high-intensity interval training (HIIT) on the cardiovascular system have already been demonstrated. However, the water environment is different from that on land. Therefore, we investigated the effects of 6-week aquatic HIIT and moderate-intensity continuous training (MICT) on central hemodynamic parameters, endothelial function, and aerobic fitness in inactive adults.

Methods

Thirty-one inactive adults were randomly assigned to HIIT or MICT group. HIIT group performed twelve 30-s swimming exercise bouts with the intensity of 95% HR_max and 15-18/20 RPE with a 60-s rest period between each bout. MICT group performed a 30-min uninterrupted swimming exercise with the intensity of 70%-75% HR_max and 12-14/20 RPE. Training frequency for both groups was three times a week. The pulse wave analysis and flow-mediated dilation (FMD) were measured by non-invasive equipments.

Results

The aerobic fitness significantly increased after HIIT, but no change was seen after MICT. Augmentation pressure (AP) and augmentation index normalized at 75 bpm (AIx@HR75) significantly decreased after HIIT but not MICT, whereas MICT rather than HIIT improved subendocardial viability ratio (SEVR), central and peripheral blood pressure, and resting HR. Only HIIT significantly increased brachial endothelial function.

Conclusion

A six-week aquatic HIIT and MICT had no differences in hemodynamic parameters, endothelial function, and aerobic fitness, however 6 weeks of aquatic HIIT reduced arterial stiffness, increased endothelial function and aerobic fitness, while 6 weeks of aquatic MICT reduced arterial blood pressure and resting HR and increased the coronary blood flow reserve.

Physical Exercise Protects Against Endothelial Dysfunction in Cardiovascular and Metabolic Diseases

Increasing evidence shows that endothelial cells play critical roles in maintaining vascular homeostasis, regulating vascular tone, inhibiting inflammatory response, suppressing lipid leakage, and preventing thrombosis. The damage or injury of endothelial cells induced by physical, chemical, and biological risk factors is a leading contributor to the development of mortal cardiovascular and cerebrovascular diseases. However, the underlying mechanism of endothelial injury remains to be elucidated. Notably, no drugs effectively targeting and mending injured vascular endothelial cells have been approved for clinical practice. There is an urgent need to understand pathways important for repairing injured vasculature that can be targeted with novel therapies. Exercise training-induced protection to endothelial injury has been well documented in clinical trials, and the underlying mechanism has been explored in animal models. This review mainly summarizes the protective effects of exercise on vascular endothelium and the recently identified potential therapeutic targets for endothelial dysfunction.

Dysfunction of perivascular adipose tissue in mesenteric artery is restored by aerobic exercise in high-fat diet induced obesity

This study investigated the function of perivascular adipose tissue (PVAT) on vascular contractility within resistant arteries in high-fat diet induced obese rats after long-term aerobic exercise. Male Sprague-Dawley rats were subjected to normal diet control group (N-CTRL), normal diet exercise group (N-EX), high-fat diet control group (H-CTRL), and high-fat diet exercise group (H-EX) (n = 8 in each group). After intervention, adipose tissues morphology was observed. Vasomotor function of mesenteric arteries with or without PVAT were assessed; mesenteric PVAT isolated from each group were transferred to chambers bath with untreated vessels (without PVAT) to evaluate the independent effect. Isolated PVAT was further pre-treated with inhibitor of cystathionine-γ-lyase (CSE), a key hydrogen sulphide (H2 S) enzyme. Results showed that the size of lipid droplet around mesenteric arteries from H-EX was significantly reduced (P < .05); uncoupling protein1 (UCP1) in PVAT from H-EX was enhanced. In N-CTRL, N-EX, and H-EX, vessels without PVAT showed higher sensitivity to serotonin (5-HT) than that with intact PVAT. Vascular tension by 5-HT was significantly reduced in H-EX than H-CTRL (P < .05) in vessels with PVAT. Transferred PVAT from H-EX compared with H-CTRL significantly reduced vascular sensitivity to 5-HT (P < .05), and this effect was eliminated through inhibiting CSE. In summary, the anti-contractile effect of PVAT on resistance artery was impaired in obesity but restored by long-term aerobic exercise. The function of PVAT modified by obesity or by exercise has an independent influence on vascular reactivity, and PVAT derived H2 S may participate in this process.

Modulations of obesity-related microRNAs after exercise intervention: a systematic review and bioinformatics analysis

Obesity is one of the prevalent health-threatening conditions; however, it is preventable by lifestyle interventions such as exercise. The molecular mechanisms underlying physiological adaptation to physical activity are not fully understood. It has been documented that both intracellular and extracellular (circulating) microRNAs (miRNAs) are involved in both obesogenic and exercise adaptation mechanisms. We aimed to conduct a systematic review of publications that examined the effect of exercise on the expression of miRNAs in individuals with obesity. In addition, bioinformatics analysis was performed on most repetitive miRNAs. PubMed, Scopus, and Google Scholar were searched with relevant keywords. We only included studies that utilized exercise as a modality for the health management of human subjects with obesity to evaluate the changes in expression of obesity-related miRNAs. Through checking of 211 retrieved articles, we reached 12 eligible studies. Some studies reported a statistically significant correlation between the change of miRNAs and clinical parameters such as body mass index and fasting glucose. In silico analysis of most repetitive miRNAs i.e. miR-126, miR-21, miR-146a, miR-221, and miR-223 resulted in the molecular signaling pathways that potentially involve in cellular adaption to exercise in people with obesity. miRNAs partake in health-related benefits of physical activity on obesity-associated cellular and molecular phenomena. However, our understanding of the exact mechanism is still in its infancy. Consistently, the clinicians waiting for the result of more integrated experiments to develop a miRNAs panel as a predictive biomarker of exercise in patients with obesity.

MicroRNAs and obesity-induced endothelial dysfunction: key paradigms in molecular therapy

The endothelium plays a pivotal role in maintaining vascular health. Obesity is a global epidemic that has seen dramatic increases in both adult and pediatric populations. Obesity perturbs the integrity of normal endothelium, leading to endothelial dysfunction which predisposes the patient to cardiovascular diseases. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNA molecules that play important roles in a variety of cellular processes such as differentiation, proliferation, apoptosis, and stress response; their alteration contributes to the development of many pathologies including obesity. Mediators of obesity-induced endothelial dysfunction include altered endothelial nitric oxide synthase (eNOS), Sirtuin 1 (SIRT1), oxidative stress, autophagy machinery and endoplasmic reticulum (ER) stress. All of these factors have been shown to be either directly or indirectly caused by gene regulatory mechanisms of miRNAs. In this review, we aim to provide a comprehensive description of the therapeutic potential of miRNAs to treat obesity-induced endothelial dysfunction. This may lead to the identification of new targets for interventions that may prevent or delay the development of obesity-related cardiovascular disease.

Cardiovascular Exosomes and MicroRNAs in Cardiovascular Physiology and Pathophysiology

Cardiac exosomes mediate cell-to-cell communication, stimulate or inhibit the activities of target cells, and affect myocardial hypertrophy, injury and infarction, ventricular remodeling, angiogenesis, and atherosclerosis. The exosomes that are released in the heart from cardiomyocytes, vascular cells, fibroblasts, and resident stem cells are hypoimmunogenic, are physiologically more stable than cardiac cells, can circulate in the body, and are able to cross the blood-brain barrier. Exosomes utilize three mechanisms for cellular communication: (1) internalization by cells, (2) direct fusion to the cell membrane, and (3) receptor-ligand interactions. Cardiac exosomes transmit proteins, mRNA, and microRNAs to other cells during both physiological and pathological process. Cardiac-specific exosome miRNAs can regulate the expression of sarcomeric genes, ion channel genes, autophagy, anti-apoptotic and anti-fibrotic activity, and angiogenesis. This review discusses the role of exosomes and microRNAs in normal myocardium, myocardial injury and infarction, atherosclerosis, and the importance of circulating microRNAs as biomarkers of cardiac disease. Graphical Abstract.

Cardiovascular inflammation: RNA takes the lead

Inflammation has recently gained tremendous attention as a key contributor in several chronic diseases. While physiological inflammation is essential to counter a wide variety of damaging stimuli and to improve wound healing, dysregulated inflammation such as in the myocardium and vasculature can promote cardiovascular diseases. Given the high severity, prevalence, and economic burden of these diseases, understanding the factors involved in the regulation of physiological inflammation is essential. Like other complex biological phenomena, RNA-based processes are emerging as major regulators of inflammatory responses. Among such processes are cis-regulatory elements in the mRNA of inflammatory genes, noncoding RNAs directing the production or localization of inflammatory cytokines/chemokines, or pathogenic RNA driving inflammatory responses. In this review, we describe several specific RNA-based molecular mechanisms by which physiological inflammation pertaining to cardiovascular diseases is regulated. These include the role of AU-rich element-containing mRNAs, long non-coding RNAs, microRNAs, and viral RNAs.

Endothelial dysfunction in diabetes and hypertension: Role of microRNAs and long non-coding RNAs

The vascular endothelium acts as a barrier between the blood flow and the inner lining of the vessel wall, and it functions as a filtering machinery to filter out any unwanted transfer of materials from both sides (i.e. the blood and the surrounding tissues). It is evident that diseases such as diabetes, obesity, and hypertension disturb the normal endothelial functions in humans and lead to endothelial dysfunction, which may further precede to the development of atherosclerosis. Long non-coding RNAs and micro RNAs both are types of non-coding RNAs which, in the recent years, have increasingly been studied in the pathophysiology of many diseases including diabetes, obesity, cardiovascular diseases, neurological diseases, and others. Recent findings have pointed out important aspects on their relevance to endothelial function as well as dysfunction of the system which may arise from presence of diseases such as diabetes and hypertension. Diabetes or hypertension-mediated endothelial dysfunction show characteristics such as reduced nitric oxide synthesis through suppression of endothelial nitric oxide synthase activity in endothelial cells, reduced sensitivity of nitric oxide in smooth muscle cells, and inflammation - all of which have been either shown to be directly caused by gene regulatory mechanisms of non-coding RNAs or shown to be having a correlation with them. In this review, we aim to discuss such findings on the role of these non-coding RNAs in diabetes or hypertension-associated endothelial dysfunction and the related mechanisms that may pave the way for alleviating endothelial dysfunction and its related complications such as atherosclerosis.