Question

Like all viral pathogens, severe acute respiratory syndrome coronavirus 2, or SARS-CoV 2 (I know, how topical), requires a cell surface receptor in order to invade a given host cell. For SARS-CoV 2, this receptor is actually the enzyme Angiotensin Converting Enzyme 2, or ACE2. ACE2 is responsible for downregulation of the Renin-Angiotensin-Aldosterone System by deactivation of Angiotensin II. Explain the RAAS in detail, including the roles played by kidneys and the lungs, and then explain what effects using recombinant human ACE2, or rhACE2, to treat acute respiratory distress syndrome could have on blood pressure.

Answer 1

RAAS is a hormonal system in our body which is responsible for the maintenance of blood pressure and fluid balance. Renin and angiotensins forms RAAS.

Renin is secreted by juxtaglomerular apparatus present in afferent arteriole in kidneys. Renin is secreted when-

1. Arterial blood pressure falls.

2. Reduction in ECF volume.

3. Increase sympathetic activity.

When renin is released into blood , it acts on a protein called angiotensinogen. By the activity of renin, the angiotensinogen in converted into angiotensin 1 and further to angiotensin 2 by the activity of angiotensin converting enzyme (ACE). This angiotensin converting enzyme is secreted by lungs.

Angiotensin 2 increases arterial blood pressure by directly acting on blood vessels and causing vasoconstriction.

As stated above, the ACE is responsible for conversion of angiotensin 1 into angiotensin 2, so if we increases ACE concentration by recombination, then the blood pressure will increase.