Calcium Signaling Pathway Is Involved in the Shedding of ACE2 Catalytic Ectodomain: New Insights for Clinical and Therapeutic Applications of ACE2 for COVID-19.

The angiotensin-converting enzyme 2 (ACE2) is a type I integral membrane that exists in two forms: the first is a transmembrane protein; the second is a soluble catalytic ectodomain of ACE2. The catalytic ectodomain of ACE2 undergoes shedding by a disintegrin and metalloproteinase domain-containing protein 17 (ADAM17), in which calmodulin mediates the calcium signaling pathway that is involved in ACE2 release, resulting in a soluble catalytic ectodomain of ACE2 that can be measured as soluble ACE2 plasma activity. The shedding of the ACE2 catalytic ectodomain plays a role in cardiac remodeling and endothelial dysfunction and is a predictor of all-cause mortality, including cardiovascular mortality. Moreover, considerable evidence supports that the ACE2 catalytic ectodomain is an essential entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Additionally, endotoxins and the pro-inflammatory cytokines interleukin (IL)-1ß and tumor necrosis factor-alpha (TNFα) all enhanced soluble catalytic ectodomain ACE2 shedding from the airway epithelia, suggesting that the shedding of ACE2 may represent a mechanism by which viral entry and infection may be controlled such as some types of betacoronavirus. In this regard, ACE2 plays an important role in inflammation and thrombotic response, and its down-regulation may aggravate COVID-19 via the renin-angiotensin system, including by promoting pathological changes in lung injury. Soluble forms of ACE2 have recently been shown to inhibit SARS-CoV-2 infection. Furthermore, given that vitamin D enhanced the shedding of ACE2, some studies reported that vitamin D treatment is associated with prognosis improvement in COVID-19. This is an updated review on the evidence, clinical, and therapeutic applications of ACE2 for COVID-19.

Concurrent Stroke and Myocardial Infarction After Mild COVID-19 Infection.

INTRODUCTION: The concurrency of both, acute stroke and acute myocardial infarction in normal conditions, outside the pandemic is rare. Coagulopathy has been associated with the inflammatory phase of coronavirus disease (COVID-19) and might be involved in this concurrency. CASES REPORT: We describe 2 patients with previous mild or no symptoms of COVID-19, admitted for acute stroke with recent/simultaneous myocardial infarction in whom admission polymerase chain reaction was negative but serologic testing diagnosed COVID-19. In these patients, concurrent stroke and myocardial infarction could have been promoted by COVID-19 infection. Management and evolution are detailed, and their contacts to confirm the COVID-19 infection. Pathogenic analysis of possible hypercoagulation state is described suggesting the hypothesis of endothelial dysfunction as the strongest mechanism involved in thrombus formation after the acute phase of COVID-19 infection. CONCLUSIONS: Our experience with these cases suggests that patients with mild symptoms can also present thromboembolic complications once the acute phase of COVID-19 infection has passed.

The soluble catalytic ectodomain of ACE2 a biomarker of cardiac remodelling: new insights for heart failure and COVID19.

The angiotensin-converting enzyme 2 (ACE2) is a type I integral membrane that was discovered two decades ago. The ACE2 exists as a transmembrane protein and as a soluble catalytic ectodomain of ACE2, also known as the soluble ACE2 that can be found in plasma and other body fluids. ACE2 regulates the local actions of the renin-angiotensin system in cardiovascular tissues, and the ACE2/Angiotensin 1-7 axis exerts protective actions in cardiovascular disease. Increasing soluble ACE2 has been associated with heart failure, cardiovascular disease, and cardiac remodelling. This is a review of the molecular structure and biochemical functions of the ACE2, as well we provided an updated on the evidence, clinical applications, and emerging potential therapies with the ACE2 in heart failure, cardiovascular disease, lung injury, and COVID-19 infection.