Current Opinion in Physiology最新文献

The ability of vascular endothelial cells to generate and conduct membrane hyperpolarization is a critical integrative mechanism controlling local blood flow and systemic blood pressure. This mechanism is particularly apparent in the microcirculation. Hyperpolarization initiated in the endothelium by receptor activation or local influences such as K⁺ stimulates vasodilation by passive, radial current spread via heterocellular myoendothelial gap junctions (MEJs) and/or the release of a diffusible factor(s). In addition, the endothelium has high-input resistance and serves as an effective conduit, conducting hyperpolarization bidirectionally through microvascular networks. This not only coordinates vasomotor responses but also causes ascending vasodilation, both of which reduce resistance sufficiently to allow an increase in tissue blood flow. These processes will be disrupted by the endothelial dysfunction in disease, helping explain why enhanced vasoreactivity and vasospasm develops in resistance arteries, limiting blood flow into the microcirculation.

Endothelial dysfunction plays a key role in the initiation and progression of pulmonary hypertension (PH), a fatal and currently incurable disease associated with increased pulmonary vascular resistance and leading to right heart failure. Recent data from genomic, transcriptomic and metabolomic studies and emergence of novel organ-on-chip technologies have provided new insights into the role of endothelium in the pathogenesis of this disease. In this review, we characterise key features of endothelial dysfunction in PH, highlighting the diversity of endothelial cell types and differences in their responses to vascular insults. We also present the current understanding of the effects of genetic mutations on endothelial function and comment on new ways of disease modelling using organ-on-chip technologies.

Dysfunction of the endothelium, a monolayer of cells in the lumen of all vessels, is found near-universally in the context of cardiovascular risk factors and diseases (CVD). Because of its crucial role in regulating vascular tone, hemostatic functions, inflammation, adhesion, and platelet activity, normalizing endothelial function is an attractive target in therapeutic approaches to CVD with prognostic implications. We will review the mechanisms leading to endothelial dysfunction in response to traditional and novel cardiovascular risk factors noise and air pollution with focus on oxidative stress and inflammation. A cardiac and vasoactive medication might attenuate vascular dysfunction based on the pathophysiology leading to the environment-induced endothelial dysfunction. The most promising approach, however, represents reductions of particulate matter with a diameter ≤2.5µm (PM_2.5) concentrations via improvements in air quality and marked reductions in transportation noise day and night levels as indicated by the World Health Organization (WHO), thereby markedly reducing the cardiovascular burden induced by noise and air pollution.

Cardiovascular disease is the leading cause of death in the world. The benefits of exercise training for cardiovascular diseases are becoming increasingly apparent. Exercise has been shown to induce physiological cardiac hypertrophy and prevent cardiovascular diseases. Therapeutic targeting of noncoding RNAs (ncRNAs) is a promising approach for the treatment of many diseases. In the cardiovascular system, ncRNAs also significantly affect the maintenance of cardiac homeostasis and cardiac function. In this short review, we provided an overview of cardiac hypertrophy, with a particular focus on physiological cardiac hypertrophy. We also summarized the current knowledge about ncRNAs-regulatory mechanisms responsible for exercise-induced physiological cardiac hypertrophy. Moreover, the perspective of further exercise-associated ncRNAs research in this field was discussed.

Sex recorded at birth, gender identity, and feminizing gender-affirming hormone therapy (fGAHT) likely contribute to cardiovascular disease (CVD) risk in transgender women. Understanding the interplay of these factors is necessary for the provision of safe, affirming, and lifesaving care. Among transgender women taking fGAHT, data show increases in CVD mortality and rates of myocardial infarction, stroke, and venous thromboembolism compared to reference populations, depending on study design and comparators. However, most studies are observational with a paucity of contextualizing information (e.g. dosing, route of administration, gonadectomy status), which makes it difficult to parse adverse fGAHT effects from confounders and interaction with known CVD risk factors (e.g. obesity, smoking, psychosocial and gender minority stressors). Increased CVD risk in transgender women points toward a need for greater attention to CVD management in this population including cardiology referral when indicated and additional research on the mechanisms and mediators of CVD risk.

Obesity is a multicausal metabolic disease. The increase in adipose tissue occurs due to hypertrophy and hyperplasia of adipose cells. As a result of these processes, an increase in inflammation will occur, promoting apoptosis, necrosis, and fibrosis of fat cells. However, the pathophysiological mechanisms involved in these processes are poorly understood. Thus, an important class of post-transcriptional gene regulators, known as microRNAs (miRNAs), has been gaining prominence for involvement in obesity. Exercise training has been described both for generating benefits in obesity and for influencing the expression of miRNAs in various types of diseases. However, the molecular mechanisms linked to exercise-regulated miRNAs in obesity still need to be better elucidated. Therefore, this review summarizes the miRNAs implicated in obesity and exercise-regulated miRNAs involved in the pathophysiological processes in obesity.

The effect of regular physical activity has been provided by numerous investigations in cardiology: both its role in primary and secondary cardiovascular prevention, as well as exercise-induced cardiac hypertrophy in athletes have already been well characterized. In this short review, we would summarize the rate of development and regression of the cardiac adaptations induced by long-term, regular training and its cessation. While most of the cross-sectional studies in sports cardiology compared athletes to healthy controls, we investigated longitudinal follow-up studies, those also have baseline data before regular exercise and/or detraining period. Intense exercise training induces significant improvement in functional characteristics after approximately two weeks, while the first marked alterations in sinus bradycardia and left ventricular (LV) hypertrophy have been observed after two months of regular physical activity. Similar tendency with some earlier reports of morphological alterations has been observed in small animal studies. Both human and experimental data imply rapid morphological, functional, and electrical regression after cessation of exercise stimulus. These information suggest that exercise-associated cardiac functional improvements (early diastolic filling, maximal oxygen uptake) of the heart manifests earlier than the morphological and electrical alterations. The increased functional properties might be the primer alteration while the morphological and electrical adaptation might be a secondary consequence of the regular hemodynamic overload of the heart and systemic circulation. The regression of exercise-induced alterations seems to be an accelerated process compared to its development.

Dietary restriction (DR) remains the most consistent preclinical intervention to improve health and lifespan across multiple species. Various DR paradigms have gained interest in recent years and many show overlapping phenotypes with calorie restriction (CR), the oldest and most established form of DR. Until recently, the impact of sex as a biological variable on DR outcomes has been understudied. Here, we review studies that have advanced our understanding of sexual dimorphism in the healthspan and lifespan responses to DR over the past five years. We particularly focus on CR, ketogenic diet, amino acid restriction, methionine restriction, and protein restriction in mice, flies, and worms.

Current heart failure (HF) therapy remains unable to substantially improve exercise capacity. Studies have shown that exercise training has beneficial effects on the heart in both health and disease. How mitochondria respond to exercise in this setting has, however, received less attention in literature. These beneficial effects may include protective changes in mitochondrial function and adaptations in substrate utilization. This review describes exercise-induced changes in cardiac metabolism, including changes in mitochondrial function and substrate utilization and their effects on cardiac function. We conclude that exercising HF patients can improve mitochondrial function and optimize substrate utilization, eventually improving or restoring cardiac function. This suggests that exercise itself should be incorporated in the HF treatment plan, to improve cardiac function and in term exercise capacity. Extending knowledge on mechanisms by which exercise exerts protective effects could potentially lead to development of therapies directed at improving mitochondrial function and substrate utilization in HF.

Endurance training is associated with increased cardiorespiratory fitness (CRF) and decreased risk of cardiovascular disease (CVD). However, a causal relationship between exercise, CRF, and CVD has not been confirmed. Exercise and CRF have a strong genetic component, estimated to be ∼50%. However, few genetic studies have been performed, as the gold-standard method for quantifying CRF is expensive, time-consuming, and requires advanced equipment. Conversely, self-reported information on physical activity (PA) is more easily available, but the uncertainty related to these data can introduce bias. Improved knowledge of genetic variants associated with exercise and CRF could provide causal links between exercise and CVD and contribute to new prevention and treatment strategies for CVD. This review presents the current knowledge of the genetics of exercise and CRF, and potential relationship with CVD, by highlighting the most comprehensive genetic and epigenetic studies on CRF, PA, and exercise response, as well as studies of gene–environment interactions.