The effects of renin-angiotensin system inhibitors (RASI) in coronavirus disease (COVID-19) with hypertension: A retrospective, single-center trial

Discovery of trans-3,4,4'-trihydroxystilbene as new lead vasorelaxant agent for antihypertensive drug development

AIMS

The structure-vasorelaxant activity relationships (SARs) assessment in previous study has found that trans-3,4,4'-trihydroxystilbene (344OH) could potentially act as a vasorelaxing agent with demonstration of over 2-fold maximal relaxation (Rmax) compared to its analogue, resveratrol. The present study focuses on the mechanism of actions and pathways employed by 344OH and compared to its analogue to further speculate the SAR of stilbenoids towards vasorelaxation.

MATERIALS AND METHODS

The 344OH employed in present study was synthesized based on the protocol in previous study. The vascular responses towards the cumulative addition of 344OH were evaluated using in vitro rat aortic rings assays.

KEY FINDINGS

The pEC50 and Rmax values were found to be 4.33 ± 0.05 and 106 ± 3.99%, respectively. Results showed that the vasorelaxation of 344OH were predominated by G-protein-coupled muscarinic- (M3) and β2-adrenergic receptors, followed by PGI2/AC/cAMP- and NO/sGC/cGMP-dependent pathways. It was also identified that 344OH employed voltage-activated- (Kv), calcium-activated- (Kca) and inwardly-rectifying (Kir) potassium channels and act as an antagonist for both VOCC and IP3R while regulating the action potential in the vasculature.

SIGNIFICANCE

The different position of hydroxyl substituent located in A-ring of the stilbenoid backbone in 344OH compared to resveratrol resulted in a significant difference in mechanistic actions that lead to 344OH's fast-acting and less time-dependent vasorelaxation behaviour. This has substantially increased the potential of 344OH to be developed as an effective antihypertensive drug in future. Present findings further strengthen our inferences where the SARs study approach should be carried out as the mainstream methodology in future drug development research.

The Interplay Between the Immune System, the Renin-Angiotensin-Aldosterone System (RAAS), and RAAS Inhibitors May Modulate the Outcome of COVID-19: A Systematic Review

Since the discovery of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), numerous research has been undertaken to delineate the various effects of the virus which manifests in many ways all over the body. The association between the SARS-CoV-2 invasion mechanism and the renin-angiotensin-aldosterone system (RAAS) receptors, created many debates about the possible consequences of using RAAS-modulating drugs including angiotensin-converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARBs) during the pandemic. Many clinical studies were conducted to assess the outcomes of coronavirus disease 2019 (COVID-19) in patients who use ACEi/ARBs following the arguments claiming to discontinue these drugs as a precautionary measure. Although several studies mainly analyzed the outcomes of the disease, this review aimed to compare specific blood markers in both groups of COVID-19 patients to gain better insight into the interaction of ACEi/ARBs with different body functions during the infection. Several databases were searched using a combination of keywords followed by screening and data extraction. Only 28 studies met our inclusion criteria, the majority of which showed no significant difference between the inflammation markers of COVID-19 patients who used or did not use ACEi/ARBs. Interestingly, 6 studies reported lower inflammatory markers in COVID-19 patients who used ACEi/ARBs, and 6 studies reported better outcomes among the same group. We therefore concluded that the use of ACEi/ARBs may not lead to worse prognosis of COVID-19 and may even play a protective role against the hyperinflammatory response associated with COVID-19.