The Renin-Angiotensin System, Hypertension, and SARS-CoV-2 Infection: a Review

Elevated Arterial Blood Pressure as a Delayed Complication Following COVID-19-A Narrative Review

Arterial hypertension is one of the most common and significant cardiovascular risk factors. There are many well-known and identified risk factors for its development. In recent times, there has been growing concern about the potential impact of COVID-19 on the cardiovascular system and its relation to arterial hypertension. Various theories have been developed that suggest a connection between COVID-19 and elevated blood pressure. However, the precise link between SARS-CoV-2 infection and the long-term risk of developing hypertension remains insufficiently explored. Therefore, the primary objective of our study was to investigate the influence of COVID-19 infection on blood pressure elevation and the subsequent risk of developing arterial hypertension over an extended period. To accomplish this, we conducted a thorough search review of relevant papers in the PubMed and SCOPUS databases up to 3 September 2023. Our analysis encompassed a total of 30 eligible articles. Out of the 30 papers we reviewed, 19 of them provided substantial evidence showing a heightened risk of developing arterial hypertension following COVID-19 infection. Eight of the studies showed that blood pressure values increased after the infection, while three of the qualified studies did not report any notable impact of COVID-19 on blood pressure levels. The precise mechanism behind the development of hypertension after COVID-19 remains unclear, but it is suggested that endothelial injury and dysfunction of the renin-angiotensin-aldosterone system may be contributory. Additionally, changes in blood pressure following COVID-19 infection could be linked to lifestyle alterations that often occur alongside the illness. Our findings emphasize the pressing requirement for thorough research into the relationship between COVID-19 and hypertension. These insights are essential for the development of effective prevention and management approaches for individuals who have experienced COVID-19 infection.

Low Ang-(1-7) and high des-Arg9 bradykinin serum levels are correlated with cardiovascular risk factors in patients with COVID-19

It is predictable that the renin-angiotensin-aldosterone and kinin-kallikrein systems are dysregulated in COVID-19 (COV) patients because SARS-CoV-2 requires ACE2 to cause an infection. This study aimed to assess the serum levels of des-arg(9)-bradykinin (DABK) and angiotensin 1-7 (ang-(1-7)) in patients with COV who had the above-mentioned cardiovascular disease risk factors. In a cross-sectional study, 69 COV patients were selected among patients referred to the main referral center for these patients, in Kerman, Iran, and 73 matched control (non-COV) individuals among individuals who participated in the KERCARD cohort study. Serum levels of DABK and ang-(1-7) were measured by ELISA in the groups of CTL (healthy), HTN, DM, OB, COV, COV + HTN, COV + DM, and COV + OB. Ang-(1-7) levels were lower in the COV + HTN group compared to the HTN group. DABK levels were higher in the COV, HTN, and OB groups and in DM + COV subjects compared to their corresponding control group. The levels of ang-(1-7) and DABK were related to HTN and OB, respectively. According to the findings, we can infer that an increase in DABK production in those with the cardiovascular disease risk factors of diabetes, obesity, and hypertension or a decrease in ang-(1-7) in those with hypertension may contribute to the adverse outcomes of SARS-CoV-2 infection.

On virus and nanomaterials - Lessons learned from the innate immune system - ACE activation in the invertebrate model Enchytraeus crypticus

Current human research on COVID-19 - SARS-CoV-2 (Severe Acute Respiratory Syndrome-Corona Virus) showed that ACE2 (Angiotensin Converting Enzyme 2) is a functional receptor to which the spike proteins attach. Invertebrates have been exposed to a wide array of threats for millennia and their immune system has evolved to deal with these efficiently. The annelid Enchytraeus crypticus, a standard ecotoxicological species, is an invertebrate species where extensive mechanisms of response studies are available, covering all levels from gene to population responses. Nanomaterials (NMs) are often perceived as invaders (e.g. virus) and can enter the cell covered by a corona, triggering similar responses. We created a database on E. crypticus ACE gene expression, aiming to analyse the potential knowledge transfer between invertebrates and vertebrates. Total exposure experiments sum 87 stress conditions for 18 different nanomaterials (NMs). ACE expression following TiO₂ NM exposure was clearly different from other NMs showing a clear (6-7 fold) ACE down-regulation, not observed for any other NMs. Other NMs, notably Ag NMs, and to some extent Cu NMs, caused ACE up-regulation (up to 4 fold). The extensive knowledge from response to NMs can support the immuno-research community, especially to develop therapies for virus that trigger the innate immune system.

Antigen presentation in SARS-CoV-2 infection: the role of class I HLA and ERAP polymorphisms

Given the highly polymorphic nature of Human Leukocyte Antigen (HLA) molecules, it is not surprising that they function as key regulators of the host immune response to almost all invading pathogens, including SARS-CoV-2, the etiological agent responsible for the recent COVID-19 pandemic. Several correlations have already been established between the expression of a specific HLA allele/haplotype and susceptibility/progression of SARS-CoV-2 infection and new ones are continuously emerging. Protective and harmful HLA variants have been described in both mild and severe forms of the disease, but considering the huge amount of existing variants, the data gathered in such a brief span of time are to some extent confusing and contradictory. The aim of this mini-review is to provide a snap-shot of the main findings so far collected on the HLA-SARS-CoV-2 interaction, so as to partially untangle this intricate yarn. As key factors in the generation of antigenic peptides to be presented by HLA molecules, ERAP1 and ERAP2 role in SARS-CoV-2 infection will be revised as well.