SARS-CoV-2: Heart Attack

SARS- CoV-2 is a type of β- coronavirus, single-stranded, positive-sense RNA virus), with an average diameter of 60–140nm. Oval or Round with spikes, is the structure of this viral particles.

Fig. Schematic Image of Corona Virus [Credit- Google Search]

The entrance of SARS- CoV-2 into cells mediated through cell surface receptors ACE2.

SARS- CoV-2 badly affects Respiratory system, Digestive system, Urogenital system, Nervous system and Circulatory system.

In this blog we focussed how SARS-CoV-2 cause Pulmonary Edema.

ACE-2 (Angiotensin Converting Enzyme-2) play a role in the pathophysiology of corona disease through the Kallikrein-kinin system.

Mechanism of infection:

ACE converts Angiotensin I into Angiotensin II, which promote vasoconstriction and inactivates Bradykinin, which is a vasodilator.

ACE-2 is countered ACE in the Renin- Angiotensin System (RAS) by converting Angiotensin-II into a metabolite, Angiotensin 1–7, that leads to vasodilation by stimulation of NO (Nitric Oxide) Synthase.

ACE-2 also hydrolyses the active metabolite of Bradykinin: des-Arg9-bradykinin, which binds to bradykinin receptors type-I (BKB1), these are present on the endothelial cells in the lungs on Bronchiolar exocrine cells and Pneumocytes type-II.

Fig. Proposed mechanism of increased vascular leakage and edema via BKB1 and BKB2 receptors. [Credit- Google Search]

Through the signalling, BKB1 receptor can induce fluid extravasation and mobilization of leucocytes to the lungs.

Suppression of ACE-2 by SARS-CoV-2 will impair the inhibition of des-Arg9-bradykinin.

Hence, increased activation of BKB1 receptors will be lead to extra fluid transversion, which results in Pulmonary Edema.

Conclusion:

In pulmonary edema the abnormal fluid buildup in lungs, that leads to shortness of breath. Due to this heart is not able to pump blood efficiently, so blood can back-up into the veins that take blood through the lungs.

As the pressure increases in these blood vessels, fluid of lungs pushed into the alveoli and this fluid reduces normal oxygen movement through the lungs.

So, we can say that due to pulmonary edema caused by SARS-CoV-2 leads to reduce the level of normal oxygen movement, which further cause congestive Heart failure.