Systemic arterial hypertension (AH) is a multifaceted disease characterized by accelerated vascular aging and high cardiometabolic morbidity and mortality. Despite extensive work in the field, the pathogenesis of AH is still incompletely understood, and its treatment remains challenging. Recent evidence has shown a deep involvement of epigenetic signals in the regulation of transcriptional programs underpinning maladaptive vascular remodeling, sympathetic activation and cardiometabolic alterations, all factors predisposing to AH. After occurring, these epigenetic changes have a long-lasting effect on gene dysregulation and do not seem to be reversible upon intensive treatment or the control of cardiovascular risk factors. Among the factors involved in arterial hypertension, microvascular dysfunction plays a central role. This review will focus on the emerging role of epigenetic changes in hypertensive-related microvascular disease, including the different cell types and tissues (endothelial cells, vascular smooth muscle cells and perivascular adipose tissue) as well as the involvement of mechanical/hemodynamic factors, namely, shear stress.

Endothelial dysfunction remains a cornerstone of diabetic vascular complications. RBCs emerge as pivotal players in endothelial dysfunction, yet the underlying mechanisms remain elusive. In this issue of the JCI , Collado et al. show that the detrimental action of RBCs on the endothelium is mediated by extracellular vesicles (EVs). EVs derived from RBCs (RBC-EVs) of patients with diabetes were taken up by the endothelium and were able to impair endothelium-dependent relaxation via an EV-mediated transfer of the prooxidant enzyme arginase-1 (Arg1) from RBCs to endothelial cells. These findings reveal events implicated in vascular oxidative stress and set the stage for personalized approaches preventing RBC-EVs’ uptake by the endothelium.

MicroRNA 451 (miR-451) is emerging as a pivotal mediator of cardiac damage in experimental models of diabetic cardiomyopathy. Whether miR-451 plays a detrimental role in the human diabetic myocardium is unknown. The present study investigates miR-451’s role in patients with type 2 diabetes (T2D). We show that miR-451 is upregulated in myocardial specimens from T2D patients compared to controls without diabetes and correlates with cardiometabolic parameters, the myocardial triglyceride content and cardiac expression of lipotoxic genes as well as echocardiographic indices of left ventricular dysfunction. Calcium-binding protein 39 (Cab39)—a known target of miR-451 in mouse hearts—was downregulated in T2D patients vs. controls, and its expression negatively correlated with that of miR-451. In cultured human cardiomyocytes (CMs), Ago2 immunoprecipitation confirmed Cab39 to be a direct target of miR-451. Treatment with a high amount of glucose (25mM) and palmitic acid (PA) mimicked miR-451 upregulation and Cab39 downregulation in human CMs. These changes were associated with increased TGs and markers of lipotoxic injury, such as elevated oxidative stress levels, mitochondrial dysfunction and apoptosis. Targeting miR-451 led to restoration of Cab39 levels while rescuing diabetes-induced lipotoxic injury and metabolic dysfunction. By contrast, miR-451 overexpression recapitulated features of lipotoxic damage. Our findings indicate miR-451 to be a potential target for the prevention of myocardial lipotoxic injury in diabetes.