The American journal of the medical sciences
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Review
The Story of Nitric Oxide, Sepsis and Methylene Blue: A Comprehensive Pathophysiologic Review.
Methylene blue (MB) is considered to be the first synthetic medication ever used in humans. There are many indications for MB, including vasoplegic shock. Nitric oxide (NO), the central mediator of sepsis, promotes vasoplegia by enhancing the guanylate cyclase cyclic guanosine monophosphate second messenger system, the effect of which is attenuated by MB. ⋯ This manuscript describes the historical aspects of the identification of NO as the endothelial derived relaxation factor and its role in the pathogenesis of vasoplegia in septic shock. An analysis of the existing evidence for the use of MB as an inhibitor of NO in vasodilatory shock is provided. The adverse effects associated with the use of MB and an approach to optimal dosing in septic shock are also addressed.
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Severe Acute Respiratory Distress Syndrome caused by a novel human coronavirus SARS-CoV-2 named COVID-19 and declared as a pandemic. This paper reviews the possibility of repurposing angiotensin type 1 receptor (AT1R) antagonists and vitamin D to treat COVID-19. ACE2 protein found on the cell membranes is the target of SARS-CoV-2 for entering into the host cells. ⋯ AT1R antagonists and vitamin D increase the expression of ACE2 independently. Besides, vitamin D suppresses the compensatory increase in renin levels following the inhibition of the renin-angiotensin system by AT1R antagonists. Therefore, a combination of AT1R antagonists and vitamin D may offer protection against COVID-19 induced lung injury.