RAAS,ACE2 and COVID-19; a mechanistic review

The use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in coronavirus disease 2019 (COVID-19) patients has been claimed as associated with the risk of COVID-19 infection and its subsequent morbidities and mortalities. These claims were resulting from the possibility of upregulating the expression of angiotensin-converting enzyme 2 (ACE2), facilitation of SARS-CoV-2 entry, and increasing the susceptibility of infection in such treated cardiovascular patients. ACE2 and renin-angiotensin-aldosterone system (RAAS) products have a critical function in controlling the severity of lung injury, fibrosis, and failure following the initiation of the disease. This review is to clarify the mechanisms beyond the possible deleterious effects of angiotensin II (Ang II), and the potential protective role of angiotensin 1–7 (Ang 1–7) against pulmonary fibrosis, with a subsequent discussion of the latest updates on ACEIs/ARBs use and COVID-19 susceptibility in the light of these mechanisms and biochemical explanation.     

Circulatory therapeutics: use of antihypertensive agents and their effects on the vasculature

This review addresses the use of the different antihypertensive agents currently available and some in development, and their effects on the vasculature. The different classes of agents used in the treatment of hypertension, and the results of recent large clinical trials, dosing protocols and adverse effects are first briefly summarized. The consequences on blood vessels of the use of antihypertensive drugs and the differential effects on the biology of large and small arteries resulting in modulation of vascular remodelling and dysfunction in hypertensive patients are then described. Large elastic conduit arteries exhibit outward hypertrophic remodelling and increased stiffness, which contributes to raise systolic blood pressure and afterload on the heart. Small resistance arteries undergo eutrophic or hypertrophic inward remodelling, and impair tissue perfusion. By these mechanisms both large and small arteries may contribute to trigger cardiovascular events. Some antihypertensive agents correct these changes, which could contribute to improved outcome. The mechanisms that at the level of the vascular wall lead to remodelling and can be beneficially affected by antihypertensive agents will also be addressed. These include vasoconstriction, growth and inflammation. The molecular pathways contributing to growth and inflammation will be summarily described. Further identification of these signalling pathways should allow identification of novel targets leading to development of new and improved medications for the treatment of hypertension and cardiovascular disease.     

Prognostic value of nutrition status in the response of cardiac resynchronization therapy

Background

Cardiac resynchronization therapy (CRT) is indicated in symptomatic heart failure (HF) patients after achieving optimal medical therapy. However, there are still a large percentage of patients who do not respond to CRT. Malnutrition is a frequent comorbidity in patients with HF, and it is associated with a poorer prognosis. Here, we evaluate the nutritional status of patients assessed by Controlling Nutritional Status (CONUT) score and its association with structural remodeling and cardiovascular events.