A computational model predicts sex-specific responses to calcium channel blockers in mammalian mesenteric vascular smooth muscle

Multi-scale modelling of the effects of ageing, hypertension and exercise on the cerebral vasculature

Ageing and hypertension both have substantial, well-documented effects on the cerebral vasculature. The effects of aerobic exercise on cerebrovascular function and development, although less well understood, have also recently received significantly increased attention. There is now clear evidence that aerobic exercise yields both short- and long-term changes to cerebrovascular health, with significant potential to improve population brain health. However, there has as yet been no mathematical model of this, making it challenging to quantify the effects of aerobic exercise. One reason for this is the very different time scales between exercise (minutes/hours) and cerebrovascular development (years/decades). Here, a new mathematical model is proposed, one that incorporates short-term changes within a longer time scale. The model is calibrated against various experimental data sources and used to quantify the effects of ageing, hypertension, and exercise interventions on lifetime cerebrovascular health. The model predicts that high-intensity exercise has a significant positive effect on cerebral health; that antihypertensive treatment has a significant positive effect even after prolonged periods of hypertension; and that different interventions can strongly interact with each other. This model provides the foundation for future quantitative investigations into the critical role of aerobic exercise and other interventions in cerebrovascular health. KEY POINTS: Exercise has a significant and lifetime positive effect on the cerebral vasculature, which can counterbalance the negative effects of ageing and hypertension. A new model is presented that incorporates the effects of all three effects on the cerebral vasculature, using multiple time scales to include both short- and long-term effects. The model is calibrated against a range of experimental data and used to quantify the effects of different exercise regimes on cerebrovascular health for the first time. This model can be used in future to explore the lifetime effects of different lifestyles and interventions on population brain health.

Amniotic membrane, a novel bioscaffold in cardiac diseases: from mechanism to applications

Cardiovascular diseases represent one of the leading causes of death worldwide. Despite significant advances in the diagnosis and treatment of these diseases, numerous challenges remain in managing them. One of these challenges is the need for replacements for damaged cardiac tissues that can restore the normal function of the heart. Amniotic membrane, as a biological scaffold with unique properties, has attracted the attention of many researchers in recent years. This membrane, extracted from the human placenta, contains growth factors, cytokines, and other biomolecules that play a crucial role in tissue repair. Its anti-inflammatory, antibacterial, and wound-healing properties have made amniotic membrane a promising option for the treatment of heart diseases. This review article examines the applications of amniotic membrane in cardiovascular diseases. By focusing on the mechanisms of action of this biological scaffold and the results of clinical studies, an attempt will be made to evaluate the potential of using amniotic membrane in the treatment of heart diseases. Additionally, the existing challenges and future prospects in this field will be discussed.

Calcium signaling in endothelial and vascular smooth muscle cells: sex differences and the influence of estrogens and androgens

Calcium signaling in vascular endothelial cells (ECs) and smooth muscle cells (VSMCs) is essential for the regulation of vascular tone. However, the changes to intracellular Ca2+ concentrations are often influenced by sex differences. Furthermore, a large body of evidence shows that sex hormone imbalance leads to dysregulation of Ca2+ signaling and this is a key factor in the pathogenesis of cardiovascular diseases. In this review, the effects of estrogens and androgens on vascular calcium-handling proteins are discussed, with emphasis on the associated genomic or nongenomic molecular mechanisms. The experimental models from which data were collected were also considered. The review highlights 1) in female ECs, transient receptor potential vanilloid 4 (TRPV4) and mitochondrial Ca2+ uniporter (MCU) enhance Ca2+-dependent nitric oxide (NO) generation. In males, only transient receptor potential canonical 3 (TRPC3) plays a fundamental role in this effect. 2) Female VSMCs have lower cytosolic Ca2+ levels than males due to differences in the activity and expression of stromal interaction molecule 1 (STIM1), calcium release-activated calcium modulator 1 (Orai1), calcium voltage-gated channel subunit-α1C (CaV1.2), Na+-K+-2Cl- symporter (NKCC1), and the Na+/K+-ATPase. 3) When compared with androgens, the influence of estrogens on Ca2+ homeostasis, vascular tone, and incidence of vascular disease is better documented. 4) Many studies use supraphysiological concentrations of sex hormones, which may limit the physiological relevance of outcomes. 5) Sex-dependent differences in Ca2+ signaling mean both sexes ought to be included in experimental design.

The formation of KV2.1 macro-clusters is required for sex-specific differences in L-type CaV1.2 clustering and function in arterial myocytes

In arterial myocytes, the canonical function of voltage-gated CaV1.2 and KV2.1 channels is to induce myocyte contraction and relaxation through their responses to membrane depolarization, respectively. Paradoxically, KV2.1 also plays a sex-specific role by promoting the clustering and activity of CaV1.2 channels. However, the impact of KV2.1 protein organization on CaV1.2 function remains poorly understood. We discovered that KV2.1 forms micro-clusters, which can transform into large macro-clusters when a critical clustering site (S590) in the channel is phosphorylated in arterial myocytes. Notably, female myocytes exhibit greater phosphorylation of S590, and macro-cluster formation compared to males. Contrary to current models, the activity of KV2.1 channels seems unrelated to density or macro-clustering in arterial myocytes. Disrupting the KV2.1 clustering site (KV2.1S590A) eliminated KV2.1 macro-clustering and sex-specific differences in CaV1.2 cluster size and activity. We propose that the degree of KV2.1 clustering tunes CaV1.2 channel function in a sex-specific manner in arterial myocytes.