Verapamil: prevention and treatment of cardio-renal syndromes in diabetic hypertensive patients?

MicroRNA-155 modulation by renin-angiotensin system inhibitors may underlie their enigmatic role in COVID-19

Severe acute respiratory coronavirus-2 (SARS-CoV-2) infection course differs between the young and healthy and the elderly with co-morbidities. In the latter a potentially lethal coronavirus disease 2019 (COVID-19) cytokine storm has been described with an unrestrained renin-angiotensin (Ang) system (RAS). RAS inhibitors [Ang converting enzyme inhibitors and Ang II type 1 receptor (AT1R) blockers] while appearing appropriate in COVID-19, display enigmatic effects ranging from protection to harm. MicroRNA-155 (miR-155)-induced translational repression of key cardiovascular (CV) genes (i.e., AT1R) restrains SARS-CoV-2-engendered RAS hyperactivity to tolerable and SARS-CoV-2-protective CV phenotypes supporting a protective erythropoietin (EPO) evolutionary landscape. MiR-155’s disrupted repression of the AT1R 1166C-allele associates with adverse CV and COVID-19 outcomes, confirming its decisive role in RAS modulation. RAS inhibition disrupts this miR-155-EPO network by further lowering EPO and miR-155 in COVID-19 with co-morbidities, thereby allowing unimpeded RAS hyperactivity to progress precariously. Current pharmacological interventions in COVID-19 employing RAS inhibition should consider these complex but potentially detrimental miR-155/EPO-related effects.

The effect of cardiac rehabilitation on cardiopulmonary function after coronary artery bypass grafting: A systematic review and meta-analysis

We carried out a meta-analysis on the effect of cardiac rehabilitation (CR) on cardiopulmonary function after coronary artery bypass grafting (CABG). Four databases were searched for studies comparing CR with control. A random-effects model was used to pool mean difference (MD). The meta-analysis showed an increase in peak oxygen consumption (peak VO2) (MD = 1.93 mL/kg/min, p = 0.0006), and 6-min walk distance (6MWD) (MD = 59.21 m, p < 0.00001), and a decrease in resting heart rate (resting HR) (MD = 5.68 bpm, p < 0.0001) in the CR group. The subgroup analysis revealed aerobic exercise could further improve resting HR and peak HR, and physical/combination with aerobic exercise could further increase 6MWD. The improvement of peak VO2, workload, resting HR, peak HR, and 6MWD regarding CR performed within one week after CABG is greater than that one week after CABG. CR after CABG can improve the cardiopulmonary function, which is reflected by the improvement of peak VO2, 6MWD, and resting HR.

MicroRNA-155 mediates endogenous angiotensin II type 1 receptor regulation: implications for innovative type 2 diabetes mellitus management

Type 2 diabetes mellitus (T2DM) is a lifelong condition and a threat to human health. Thorough understanding of its pathogenesis is acutely needed in order to devise innovative, preventative, and potentially curative pharmacological interventions. MicroRNAs (miRNA), are small, non-coding, one-stranded RNA molecules, that can target and silence around 60% of all human genes through translational repression. MiR-155 is an ancient, evolutionarily well-conserved miRNA, with distinct expression profiles and multifunctionality, and a target repertoire of over 241 genes involved in numerous physiological and pathological processes including hematopoietic lineage differentiation, immunity, inflammation, viral infections, cancer, cardiovascular conditions, and particularly diabetes mellitus. MiR-155 Levels are progressively reduced in aging, obesity, sarcopenia, and T2DM. Thus, the loss of coordinated repression of multiple miR-155 targets acting as negative regulators, such as C/EBPβ, HDAC4, and SOCS1 impacts insulin signaling, deteriorating glucose homeostasis, and causing insulin resistance (IR). Moreover, deranged regulation of the renin angiotensin aldo-sterone system (RAAS) through loss of Angiotensin II Type 1 receptor downregulation, and negated repression of ETS-1, results in unopposed detrimental Angiotensin II effects, further promoting IR. Finally, loss of BACH1 and SOCS1 repression abolishes cytoprotective, anti-oxidant, anti-apoptotic, and anti-inflammatory cellular pathways, and promotes β-cell loss. In contrast to RAAS inhibitor treatments that further decrease already reduced miR-155 Levels, strategies to increase an ailing miR-155 production in T2DM, e.g., the use of metformin, mineralocorticoid receptor blockers (spironolactone, eplerenone, finerenone), and verapamil, alone or in various combinations, represent current treatment options. In the future, direct tissue delivery of miRNA analogs is likely.