Association of angiotensin-converting enzyme 2 gene polymorphism and enzymatic activity with essential hypertension in different gender: A case-control study

Sex differences in the outcome of critically Ill patients with COVID-19 - An international multicenter critical care consortium study

BACKGROUND

Sex differences in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) susceptibility, illness severity, and hospital course are widely acknowledged. The effects of sex on outcomes experienced by patients with severe Coronavirus Disease 2019 (COVID-19) admitted to the intensive care unit (ICU) remains unknown.

OBJECTIVES

To determine the effects of sex on ICU mortality in patients with COVID-19 METHODS: This retrospective analysis of an international multi-center prospective observational database included adults admitted to ICU for treatment of acute COVID-19 between 1st January 2020 and 30th June 2022. The primary outcome was ICU mortality. Multivariable Cox regression was used to ascertain the hazard of death (Hazard Ratio=HR) adjusted for pre-selected covariates. The secondary outcome was sex differences in complications of COVID-19 during hospital stay.

RESULTS

Overall, 10,259 patients (3,314 females, 6,945 males) were included with a median age of 60 (interquartile range [IQR]=49-68) and 59 (IQR=49-67) years, respectively. Baseline characteristics were similar between sexes. More females were non-smokers (65% vs. 44 %, p < 0.01) and obese (39% vs. 30 %, p < 0.01), compared to males. Also, males received greater ICU intervention (mechanical ventilation, prone ventilation, vasopressors, and tracheostomy) than females. Males had a greater hazard of death (compared to females, HR=1.14; 95 % CI=1.02-1.26). Adjustment for complications during hospital stay did not alter the hazard of death (HR=1.16; 95 % CI=1.05-1.28). Males had a significantly elevated hazard of death among patients who received ECMO (HR=1.24; 95 % CI=1.01-1.53). Male sex was associated with cardiac arrest (adjusted OR [aOR]=1.37; 95 % CI=1.16-1.62) and PE (aOR=1.28; 95 % CI=1.06-1.55).

CONCLUSION

Among patients admitted to ICU for severe COVID-19, males experienced higher severity of illness and more frequent intervention than females. Ultimately, the hazard of death was moderately elevated in males compared to females despite greater PE and cardiac arrest.

Genetic variations in ACE2 gene associated with metabolic syndrome in southern China: a case-control study

Metabolic syndrome (MetS) is closely related to cardiovascular and cerebrovascular diseases, and genetic predisposition is one of the main triggers for its development. To identify the susceptibility genes for MetS, we investigated the relationship between angiotensin-converting enzyme 2 (ACE2) single nucleotide polymorphisms (SNPs) and MetS in southern China. In total, 339 MetS patients and 398 non-MetS hospitalized patients were recruited. Four ACE2 polymorphisms (rs2074192, rs2106809, rs879922, and rs4646155) were genotyped using the polymerase chain reaction-ligase detection method and tested for their potential association with MetS and its related components. ACE2 rs2074192 and rs2106809 minor alleles conferred 2.485-fold and 3.313-fold greater risks of MetS in women. ACE2 rs2074192 and rs2106809 variants were risk factors for obesity, diabetes, and low-high-density lipoprotein cholesterolemia. However, in men, the ACE2 rs2074192 minor allele was associated with an approximately 0.525-fold reduction in MetS prevalence. Further comparing the components of MetS, ACE2 rs2074192 and rs2106809 variants reduced the risk of obesity and high triglyceride levels. In conclusion, ACE2 rs2074192 and rs2106809 SNPs were independently associated with MetS in a southern Chinese population and showed gender heterogeneity, which can be partially explained by obesity. Thus, these SNPs may be utilized as predictive biomarkers and molecular targets for MetS. A limitation of this study is that environmental and lifestyle differences, as well as genetic heterogeneity among different populations, were not considered in the analysis.

Association of insertion /deletion polymorphism of ace gene with essential hypertension in patients of Khyber Pakhtunkhwa

Objective &Background

The exact cause of hypertension is unknown in about 90 to 95% patients, known as essential hypertension. Genes may play a crucial role in the pathology of essential hypertension. Gene for angiotensin converting enzyme (ACE) is found on long arm of chromosome 17q23, where 287 base pair insertion or deletion (I/D) polymorphism may occur. This study was aimed to assess the association of I/D polymorphism of ACE gene with blood pressure (BP) in Patients of Khyber Pakhtunkhwa (KPK).

Methods

This Descriptive Cross-sectional study was conducted from 1st June 2021 to 30th September 2021 at Kuwait Teaching Hospital, Peshawar. The genomic DNA was extracted from lymphocytes and PCR was performed for identification of ACE I/D polymorphism.

Results

Total 181 individuals (121 Hypertensive and 60 normal) were enrolled in the study. The measured systolic and diastolic BP in cases were 153.91mmHg±12.65 and 92.94mmHg±5.72, respectively while in control were 118.20±17.13 and 74.12mmHg±7.58, respectively. The Deletion Homozygous (DD), Insertion Homozygous (II) and Deletion and Insertion Heterozygous (DI) genotypes in hypertensive patients were 47 (38.84%), 17 (14.04%) and 57 (47.10%) respectively while in Control group the DD, II and DI were 4 (6.66%), 25 (41.66%) and 31 (51.66%) respectively. This study showed association of DD genotypes of the ACE gene with hypertension as compared to healthy individuals.

Conclusion

Individuals with DD genotype may have association with hypertension. polymorphism of ACE gene was proved to be an important genetic marker for essential hypertension in Patients of KPK.

Genetic Variations in the Human Angiotensin-ConvertingEnzyme 2 and Susceptibility to Coronavirus Disease-19

Background

Health and economies are both affected by the coronavirus disease-19 (COVID-19) global pandemic. Angiotensin-converting enzyme 2 (ACE2) is a polymorphic enzyme that is a part of the renin-angiotensin system, and it plays a crucial role in viral entry. Previous investigations and studies revealed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and ACE2 have a considerable association. Recently, ACE2 variants have been described in human populations in association with cardiovascular and pulmonary conditions. In this study, genetic susceptibility to COVID-19 in different populations was investigated.

Methods and Results

We evaluated the identified variants based on the predictive performance of 5 deleteriousness-scoring methods and the 2015 American College of Medical Genetics and Genomics (ACMG) guidelines. The results indicated 299 variants within the ACE2 gene. The variants were analyzed by different in-silico analysis tools to assess their functional effects. Ultimately, 5 more deleterious variants were found in the ACE2 gene.

Conclusions

Collecting more information about the variations in binding affinity between SARS-CoV-2 and host-cell receptors due to ACE2 variants leads to progress in treatment strategies for COVID-19. The evidence accumulated in this study showed that ACE2 variants in different populations may be associated with the genetic susceptibility, symptoms, and outcome of SARS-CoV-2 infection.

The RAAS Goodfellas in Cardiovascular System

In the last two decades, the study of the renin-angiotensin-aldosterone system (RAAS) has revealed a counterregulatory protective axis. This protective arm is characterized by ACE2/Ang 1-7/MasR and Ang 1-9 that largely counteracts the classic arm of the RAAS mediated by ACE/Ang II/AT1R/aldosterone and plays an important role in the prevention of inflammation, oxidative stress, hypertension, and cardiovascular remodeling. A growing body of evidence suggests that enhancement of this counterregulatory arm of RAAS represents an important therapeutic approach to facing cardiovascular comorbidities. In this review, we provide an overview of the beneficial effects of ACE2, Ang 1-7/MasR, and Ang 1-9 in the context of oxidative stress, vascular dysfunction, and organ damage.

ACE2 gene polymorphisms are associated with elevated pulmonary artery pressure in congenital heart diseases

BACKGROUNDS

Angiotensin converting enzyme 2 (ACE2) polymorphisms are related to the occurrence and prognosis of cardiovascular disease. However, whether ACE2 polymorphisms also affect pulmonary circulation in congenital heart disease (CHD) remains unclear. Thus, we investigated the relationship between ACE2 single nucleotide polymorphism (SNPs) and pulmonary circulation in CHD patients of Chinese Han ethnicity.

METHODS

Enrolled CHD patients (n = 367) underwent gene sequencing of ACE2 SNPs rs2074192, rs2285666, and rs2106809. Patients with pulmonary hypertension were further examined for detailed hemodynamics.

RESULTS

Female heterozygous patients had worse pulmonary circulation hemodynamic parameters compared to those of homozygotes. Female CHD patients with the CCA (OR = 0.53, 95% CI: 0.32-0.88) or CCG (OR = 0.59, 95% CI: 0.35-0.99) haplotype had a lower risk of elevated pulmonary artery pressure.

CONCLUSION

In female CHD patients, ACE2 SNPs are related to pulmonary circulation hemodynamics. Female CHD patients with the CCA and CCG haplotype had a lower risk of pulmonary hypertension.

A comprehensive review of ACE2, ACE1, TMPRSS2 and IFITM3 gene polymorphisms and their effect on the severity of COVID-19

Recent events have raised concerns about the outbreak of a pandemic by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). An infection caused by a virus can provoke an inflammatory reaction, which can result in severe lung damage, failure of several organs, and death. The unique genetic makeup of each individual may be a component in the development of each of these responses. In this context, genetic variants of the genes linked to the invasion of the virus into the host's body can be analyzed. Various elements have a function in viral entry. ACE2 is used by SARS-CoV-2 as a receptor to enter the cell. TMPRSS2 is then responsible for cutting the virus into its components. In addition, lung damage occurs when there is an imbalance between ACE1 and ACE2. Another component that plays a significant role in virus penetration is called IFITM3, which is created as a reaction to interferon. This protein prevents viruses in the Coronaviridae family from entering cells. This study aimed to analyze DNA polymorphisms in the ACE2, ACE1, TMPRSS2, and IFITM3 genes. Findings showed certain polymorphisms appear to be associated with the severity of the disease, including respiratory, coronary, and neurological disorders. The results also indicated that certain polymorphisms were protective against this virus. Varying populations have a different frequency of high-risk polymorphisms, so different treatment and preventative techniques must be implemented. Additional population studies should be conducted in this region to reduce the incidence of COVID-19-related morbidity and mortality.

Impacts of SARS-CoV-2 on diabetes mellitus: A pre and post pandemic evaluation

The coronavirus disease 2019 (COVID-19) pandemic caused by the novel beta coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) crippled the whole world and has resulted in large number of morbidity and mortality. The origin of the SARS-CoV-2 is still disputed. The risk of infection with SARS-CoV-2 is dependent on several risk factors as observed in many studies. The severity of the disease depends on many factors including the viral strain, host immunogenetics, environmental factors, host genetics, host nutritional status and presence of comorbidities like hypertension, diabetes, Chronic Obstructive Pulmonary Disease, cardiovascular disease, renal impairment. Diabetes is a metabolic disorder mainly characterized by hyperglycemia. Diabetic individuals are intrinsically prone to infections. SARS-CoV-2 infection in patients with diabetes result in β-cell damage and cytokine storm. Damage to the cells impairs the equilibrium of glucose, leading to hyperglycemia. The ensuing cytokine storm causes insulin resistance, especially in the muscles and liver, which also causes a hyperglycemic state. All of these increase the severity of COVID-19. Genetics also play pivotal role in disease pathogenesis. This review article focuses from the probable sources of coronaviruses and SARS-CoV-2 to its impacts on individuals with diabetes and host genetics in pre- and post-pandemic era.

A systematic review of nonsynonymous single nucleotide polymorphisms in the renin-angiotensin-aldosterone system

In this recent publication review the authors aimed to collect evidence of impact of nonsynonymous single nucleotide polymorphisms (nsSNP) in the renin-angiotensin-aldosterone system on patients' phenotype not only regarding arterial hypertension and its complications, but also the impact on other diseases of interest outside the field of cardiovascular medicine. PubMed database records published between 2017-2020 were searched and all positive case-control studies or positive studies with human DNA were selected. The search identified 104 articles, of which 22 were included on the basis of the inclusion criteria. This paper presents the impact of 44 nsSNPs in panels for genes of renin, angiotensinogen, angiotensin-converting enzyme, angiotensin receptor and aldosterone on the clinical picture of investigated cohorts or on the peptide-protein interactions as consequence of nsSNPs. Genetic variability in nsSNPs of the RAAS is involved in the pathogenesis of arterial hypertension and its complications, and surprisingly also in the pathogenesis of conditions not associated with elevated blood pressure, like neoplasms or inflammatory diseases.

Circulating Plasma Concentrations of ACE2 in Primary Aldosteronism and Cardiovascular Outcomes

CONTEXT

The plasma concentrations of angiotensin-converting enzyme 2 (pACE2) has been independently associated with cardiovascular diseases.

OBJECTIVE

Higher pACE2 concentrations may be found in patients with primary aldosteronism (PA) and might lead to increased cardiovascular events.

METHODS

Using an inception observational cohort, we examined pACE2 among 168 incident patients with PA. The expression of ACE2, serine protease 2 (TMPRSS2), and metalloprotease 17 (ADAM17) were assessed in peripheral blood mononuclear cells.

RESULTS

Incident PA and essential hypertension (EH) patients had similarly elevated pACE2 (47.04 ± 22.06 vs 46.73 ± 21.06 ng/mL; P = .937). Age was negatively (β = -2.15; P = .033) and higher serum potassium level (β = 2.29; P = .024) was positively correlated with higher pACE2 in PA patients. Clinical complete hypertension remission after adrenalectomy (Primary Aldosteronism Surgery Outcome criteria) was achieved in 36 (50%) of 72 surgically treated unilateral PA (uPA) patients. At follow-up, pACE2 decreased in surgically treated patients who had (P < .001) or had no (P = .006) hypertension remission, but the pACE2 attenuation was not statistically significant in uPA (P = .085) and bilateral PA (P = .409) administered with mineralocorticoid receptor antagonist (MRA). Persistently elevated pACE2 (> 23 ng/mL) after targeted treatments was related to all-cause mortality and cardiovascular events among PA patients (hazard ratio = 8.8; P = .04); with a mean follow-up of 3.29 years. TMPRSS2 messenger RNA (mRNA) expression was higher in uPA (P = .018) and EH (P = .038) patients than in normotensive controls; it was also decreased after adrenalectomy (P < .001).

CONCLUSION

PA and EH patients had elevated pACE2 and higher expression of TMPRSS2 mRNA compared to those of normotensive population. Persistently elevated pACE2 (> 23 ng/mL) after targeted treatments was associated risk of mortality and incident cardiovascular events.

Concentrations of Soluble Angiotensin Converting Enzyme 2 (sACE2) in Children and Adults with and without COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing the coronavirus disease 2019 (COVID-19) pandemic, leads to illness and death. Various risk factors for a severe course, such as higher age, male gender and pre-existing illnesses are known. However, pathophysiological risk factors are largely unclear. Notably, the mild course of disease in children is conspicuous. Angiotensin converting enzyme 2 (ACE2) serves as a receptor for SARS-CoV-2 and is a key enzyme in infection. Differences in the distribution of ACE2 can provide insights into different courses of COVID-19. Our aim was to elucidate the role of ACE2 as a pathophysiological risk factor by measuring soluble ACE2 (sACE2) via ELISA in blood samples (lithium-heparin-plasma or serum) of 367 individuals including children and adults with and without COVID-19. sACE2-levels were compared between the groups according to age and sex. In adults and children with COVID-19, sACE2-concentrations are significantly higher compared to healthy individuals. sACE2-levels increase with age and are lower in children compared to adults with COVID-19. Sex doesn't significantly influence sACE2-concentration. It remains unclear whether sACE2 concentrations increase because of the infection and what factors could influence this response. In conclusion, the increase of sACE2-concentration with age could indicate that ACE2 concentrations mirror increased COVID-19 severity.

Perinatal Transmission and Outcomes of SARS-CoV-2 Infection

Maternal SARS-CoV-2 infection can adversely affect the birth and neonatal outcomes. The authors prospectively enrolled 196 neonates born to 193 SARS-CoV-2-positive mothers to determine the rate of mother-to-baby transmission of SARS-CoV-2 and its effect on short-term neonatal outcomes in Indian population. Nineteen babies turned out to be RT-PCR-positive for SARS-CoV-2, carrying a perinatal transmission rate of 9.8%. Rates of prematurity and low birth weight were 12.8% and 18.9% in the neonatal group, respectively. On comparing SARS-CoV-2-positive (n = 19) and negative (n = 177) neonatal groups, rate of prematurity, hospital admission rate, and death rate were higher in the former group. The placental positivity rate for SARS-CoV-2 was 8.1%, but no relation was found between placental and neonatal infection.

Angiotensin-converting Enzyme-2 (ACE2) Expression in Pediatric Liver Disease

The membrane protein angiotensin-converting enzyme-2 (ACE2) has gained notoriety as the receptor for severe acute respiratory syndrome coronavirus 2. Prior evidence has shown ACE2 is expressed within the liver but its function has not been fully discerned. Here, we utilized novel methodology to assess ACE2 expression in pediatric immune-mediated liver disease to better understand its presence in liver diseases and its role during infections such as COVID-19. We stained liver tissue with ACE2-specific immunofluorescent antibodies, analyzed via confocal microscopy. Computational deep learning-based segmentation models identified nuclei and cells, allowing the quantification of mean cellular and cytosolic immunofluorescent. Spatial transcriptomics provided high-throughput gene expression analysis in tissue to determine cellular composition for ACE2 expression. ACE2 plasma expression was quantified via enzyme-linked immunosorbent assay. High ACE2 expression was seen at the apical surface of cholangiocytes, with lower expression within hepatocyte cytosol and nonparenchymal cells (P<0.001). Children with liver disease had higher ACE2 hepatic expression than pediatric control tissue (P<0.001). Adult control tissue had higher expression than pediatric control (P<0.001). Plasma ACE2 was not found to be statistically different between samples. Spatial transcriptomics identified cell composition of ACE2-expressing spots containing antibody-secreting cells. Our results show ACE2 expression throughout the liver, with strongest localization to cholangiocyte membranes. Machine learning can be used to rapidly identify hepatic cellular components for histologic analysis. ACE2 expression in the liver may be increased in pediatric liver disease. Future work is needed to better understand the role of ACE2 in chronic disease and acute infections.

Association of ACE2 Gene Variants with the Severity of COVID-19 Disease-A Prospective Observational Study

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 virus (SARS-CoV-2), has triggered an enormous scientific response. Many studies have focused on understanding the entry of the SARS-CoV-2 virus into the host cell. The angiotensin-converting enzyme-2 (ACE2) is recognized as the host receptor used by SARS-CoV-2 to enter its target cells. Recent studies suggest that ACE2 gene polymorphisms might be candidates for genetic susceptibility to SARS-CoV-2 infection. The aim of this study is to evaluate the influence of ACE2 polymorphisms on COVID-19 disease risk and severity. In our study, we confirmed that there is a statistically significant increased risk of a more severe disease course of SARS-CoV-2 infection associated with the need for hospitalization in intensive care for patients with specific polymorphisms of the ACE2 gene. The most significant correlation was found for variant ACE2 rs2285666 (AA allele, OR = 2.12, p = 0.0189) and ACE2 rs2074192 (TT allele, OR = 2.05, p = 0.0016), and for ACE2 rs4646174 (GG allele, OR = 1.93, p = 0.0016), ACE2 rs4646156 (TT allele OR = 1.71, p = 0.008) and ACE2 rs2158083 (TT allele OR = 1.84, p = 0.0025). In conclusion, our findings identify that certain ACE2 polymorphisms impact the severity of COVID-19 disease independently of other well-known risk factors.

Association of ACE2 Polymorphisms and Derived Haplotypes With Obesity and Hyperlipidemia in Female Spanish Adolescents

Background

In the cardiovascular (CV) system, overactivation of the angiotensin converting enzyme (ACE) may trigger deleterious responses derived from angiotensin (Ang)-II, which can be attenuated by stimulation of ACE2 and subsequent Ang-(1-7) metabolite. However, ACE2 exhibits a high degree of genetic polymorphism that may affect its structure and stability, interfering with these cardioprotective actions. The aim of this study was to analyse the relationship of ACE2 polymorphisms with cardiovascular risk factors in children.

Methodology

Five ACE2-single nucleotide polymorphisms (SNP), rs4646188, rs2158083, rs233575, rs879922, and rs2074192, previously related to CV risk factors, were analyzed in a representative sample of 12–16-year-old children and tested for their potential association with anthropometric parameters, insulin levels and the lipid profile.

Results

Girls (N = 461) exhibited lower rates of overweight, obesity, blood pressure, and glycemia than boys (N = 412), though increased plasma lipids. The triglycerides (TG)/HDL-C ratio was, however, lower in females. Interestingly, only in girls, the occurrence of overweight/obesity was associated with the SNPs rs879922 [OR 1.67 (1.02–2.75)], rs233575 [OR 1.98 (1.21- 3.22)] and rs2158083 [OR 1.67 (1.04–2.68)]. Also, TG levels were linked to the rs879922, rs233575, and rs2158083 SNPs, and the TG/HDL-C ratio was associated with rs879922 and rs233575. Levels of TC and LDL-C were associated with rs2074192 and rs2158083. Furthermore, the established cut-off level for TG ≥ 90 mg/dL was related to rs879922 [OR 1.78 (1.06–2.96)], rs2158083 [OR 1.75 (1.08–2.82)], and rs233575 [OR 1.62 (1.00–2.61)]. The cut-off level for TC ≥ 170 mg/dL was associated with rs2074192 OR 1.54 (1.04–2.28) and rs2158083 [OR 1.53 (1.04–2.25)]. Additionally, the haplotype (C-G-C) derived from rs879922-rs2158083-rs233575 was related to higher prevalence of overweight/obesity and TG elevation.

Conclusion

The expression and activity of ACE2 may be essential for CV homeostasis. Interestingly, the ACE2-SNPs rs879922, rs233575, rs2158083 and rs2074192, and the haplotype (C-G-C) of the three former could induce vulnerability to obesity and hyperlipidemia in women. Thus, these SNPs might be used as predictive biomarkers for CV diseases and as molecular targets for CV therapy.

Elevated mid-pregnancy plasma levels of angiotensin-converting enzyme 2 in women prior to the development of preeclampsia

Preeclampsia and cardiovascular disease (CVD) share multiple features and risk factors. Circulating angiotensin-converting enzyme 2 (ACE2) is increased in CVD and mediates SARS-CoV-2 entry into host cells, causing COVID-19 infection. The role of ACE2 in preeclampsia pathophysiology is unknown. We hypothesized that circulating ACE2 is increased in mid-pregnancy in women later developing preeclampsia. We included 296 women later developing preeclampsia (cases) and 333 women with a continuous healthy pregnancy (controls). Circulating ACE2 was measured with an immunoassay based on proximity extension assay technology, with levels being expressed as relative quantification on a log2 scale. Median (interquartile range) ACE2 levels were higher in cases than in controls; 3.84 (3.50–4.24) vs. 3.72 (3.45–4.04), p = 0.002. Adjusted logistic regression models showed a 60% increased risk for later development of preeclampsia with one unit elevation of ACE2 (adjusted odds ratio (aOR) 1.60, 95% confidence intervals (CI) 1.17–2.18). Preterm preeclampsia (diagnosis before 37 gestational weeks, n = 97) seemed to have a stronger ACE2 association than term preeclampsia, n = 199 (aORs, 95% Cis 2.14, 1.15–3.96 and 1.52, 1.04–2.23, respectively). Circulating ACE2 is increased at mid-pregnancy in women later developing preeclampsia, particularly preterm preeclampsia. Thus, our finding indicates a partly shared pathophysiological pathway between preeclampsia and CVD.

Role and interaction between ACE1, ACE2 and their related genes in cardiovascular disorders

Cardiovascular disease is the greatest health care burden and one of the most common causes of death worldwide. Less is known about the genetic factors that are responsible for predisposition to cardiovascular disease thus; the molecular and genetic mechanisms underlying cardiovascular diseases remain obscure. One important regulator of blood pressure homeostasis is the renin-angiotensin system (RAS). The protease renin cleaves angiotensinogen into the inactive decameric peptide angiotensin I (AngI). Angiotensin-converting enzyme (ACE) catalyzes the cleavage of the Ang I into the active octomer angiotensin II (Ang II). In humans, can ACE polymorphism has been associated with determinants of renal and cardiovascular function and pharmacological inhibition of ACE and Ang II receptors are effective in lowering blood pressure and preventing kidney disease. In addition, inhibition of ACE and Ang II receptors has beneficial effects in heart failure. A homologue of ACE, termed ACE2, has been identified; it is predominantly expressed in the vascular endothelial cells of the kidney and heart. Unlike ACE, ACE2 functions as a carboxypeptidase, cleaving a single residue from AngI, generating Ang1-9, and a single residue from AngII to generate Ang1-7. Nevertheless, the in vivo role of ACE2 in the cardiovascular system and the RAS is not known.

Molecular and Physiological Aspects of SARS-CoV-2 Infection in Women and Pregnancy

Whilst scientific knowledge about SARS-CoV-2 and COVID-19 is rapidly increasing, much of the effects on pregnant women is still unknown. To accommodate pregnancy, the human endometrium must undergo a physiological transformation called decidualization. These changes encompass the remodeling of endometrial immune cells leading to immunotolerance of the semi-allogenic conceptus as well as defense against pathogens. The angiotensin converting enzyme 2 (ACE2) plays an important regulatory role in the renin-angiotensin-system (RAS) and has been shown to be protective against comorbidities known to worsen COVID-19 outcomes. Furthermore, ACE2 is also crucial for decidualization and thus for early gestation. An astounding gender difference has been found in COVID-19 with male patients presenting with more severe cases and higher mortality rates. This could be attributed to differences in sex chromosomes, hormone levels and behavior patterns. Despite profound changes in the female body during pregnancy, expectant mothers do not face worse outcomes compared with non-pregnant women. Whereas mother-to-child transmission through respiratory droplets during labor or in the postnatal period is known, another question of in utero transmission remains unanswered. Evidence of placental SARS-CoV-2 infection and expression of viral entry receptors at the maternal-fetal interface suggests the possibility of in utero transmission. SARS-CoV-2 can cause further harm through placental damage, maternal systemic inflammation, and hindered access to health care during the pandemic. More research on the effects of COVID-19 during early pregnancy as well as vaccination and treatment options for gravid patients is urgently needed.

Why Does the Severity of COVID-19 Differ With Age?: Understanding the Mechanisms Underlying the Age Gradient in Outcome Following SARS-CoV-2 Infection

Although there are many hypotheses for the age-related difference in the severity of COVID-19, differences in innate, adaptive and heterologous immunity, together with differences in endothelial and clotting function, are the most likely mechanisms underlying the marked age gradient. Children have a faster and stronger innate immune response to SARS-CoV-2, especially in the nasal mucosa, which rapidly controls the virus. In contrast, adults can have an overactive, dysregulated and less effective innate response that leads to uncontrolled pro-inflammatory cytokine production and tissue injury. More recent exposure to other viruses and routine vaccines in children might be associated with protective cross-reactive antibodies and T cells against SARS-CoV-2. There is less evidence to support other mechanisms that have been proposed to explain the age-related difference in outcome following SARS-CoV-2 infection, including pre-existing immunity from exposure to common circulating coronaviruses, differences in the distribution and expression of the entry receptors ACE2 and TMPRSS2, and difference in viral load.

An Updated Review on the Role of Single Nucleotide Polymorphisms in COVID-19 Disease Severity: A Global Aspect

Abstract:

Coronavirus disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and recently has become a serious global pandemic. Age, gender, and comorbidities are known to be common risk factors for severe COVID-19 but are not enough to fully explain the magnitude of their effect on the risk of severity of the disease. Single nucleotide polymorphisms (SNPs) in several genes have been reported as a genetic factor contributing to COVID-19 severity. This comprehensive review focuses on the association between SNPs in four important genes and COVID-19 severity in a global aspect. We discuss a total of 39 SNPs in this review: five SNPs in the ABO gene, nine SNPs in the angiotensin-converting enzyme 2 (ACE2) gene, 19 SNPs in the transmembrane protease serine 2 (TMPRSS2) gene, and six SNPs in the toll-like receptor 7 (TLR7) gene. These SNPs data could assist in monitoring an individual's risk of severe COVID-19 disease, and therefore personalized management and pharmaceutical treatment could be planned in COVID-19 patients.

Associations between the TNMD rs4828038 and ACE2 rs879922 polymorphisms and preeclampsia susceptibility: a case-control study

A case-control study was designed to investigate the association between the angiotensin converting enzyme 2 (ACE2) rs879922, glucose-6-phosphate dehydrogenase (G6PD) rs1050828, and tenomodulin (TNMD) rs4828038 single nucleotide polymorphisms (SNPs), and preeclampsia. A total of 356 Han Chinese pregnant women (170 controls and 186 cases) were recruited into the study. ACE2 rs879922, G6PD rs1050828, and TNMD rs4828038 were tested by the targeted next-generation sequencing technology and the data were analyzed using SPSS version 18. Genotyping of results revealed that patients with the CC/CT genotype in SNP rs4828038 or CC/CG genotype in SNP rs879922 had a significantly decreased susceptibility to late-onset preeclampsia (CC/CT versus TT: OR = 0.543, 95% CI = 0.378 to 0.779, p = .001; CC/CG versus GG: OR = 0.510, 95% CI = 0.038 to 0.860, p = .012). Our study found that the polymorphisms TNMD rs4828038 and ACE2 rs879922 might be associated with late-onset preeclampsia.IMPACT STATEMENTWhat is already known on this subject? Preeclampsia is associated with multiple SNPs, and ACE2 rs879922, G6PD rs1050828, and TNMD rs4828038 are related to essential hypertension and glucose and lipid metabolism disorders. Essential hypertension, diabetes, and dyslipidemia are risks for preeclampsia. The associations between those three SNPs and preeclampsia have not been reported.What do the results of this study add? The polymorphisms of TNMD rs4828038 and ACE2 rs879922 might be associated with the risk of late-onset preeclampsia. There was no relationship between SNP rs1050828 and preeclampsia.What are the implications of these findings for clinical practice and/or further research? TNMD rs4828038 and ACE2 rs879922 might be target sites for genetic diagnosis and therapy, and the levels of mRNA and protein in pregnant women with preeclampsia should be further tested.

Insights on Epidemiology, Pathogenesis, Diagnosis and Possible Treatment of COVID-19 Infection

The sudden outbreak of the novel coronavirus infection (COVID-19, SARS-CoV-2 virus) is posing a significant threat by affecting millions of people across the globe showing mild to severe symptoms of pneumonia and acute respiratory distress. The absence of precise information on primary transmission, diagnosis, prognosis, and therapeutics for patients with COVID-19 makes prevention and control tough. In the current scenario, only supportive treatment is available, which in turn possess a biggest challenge for scientists to develop specific drugs and vaccines for COVID-19. Further, India, with the second largest populated country and fluctuating climatic conditions quarterly, has high vulnerability towards COVID-19 infection. Thus, this highlights the importance of a better understanding of the COVID-19 infection, pathology, diagnosis and its treatment. The present review article has been intended to discuss the COVID-19 biology, mechanism of infection in humans with primary effects on pregnancy, the nervous system, diabetes, and cardiovascular disease. The article will also discuss the drug repurposing strategy as an alternative line of treatment and clinical practices recommended by the World Health Organization and other government agencies and represent the COVID-19 scenario with the Indian context.

COVID-19: The Cause of the Manifested Cardiovascular Complications During the Pandemic

In the course of human history, we encountered several devastating waves of pandemics, affecting millions of lives globally and now the rapid and progressive spread of the novel SARS-CoV-2, causing Coronavirus disease (COVID-19) has created a worldwide wave of crisis. Profoundly straining national health care systems, it also significantly impacted the global economic stability. With the introduction of COVID-19 measures, mainly driven by immunization drives, casualties due to the virus were reported to decrease considerably. But then comes into play the post-Covid morbidities, along with their short and long-term effects on the elderly and the co-morbid population. Moreover, the pediatric population and the otherwise healthy cohort of the young athletes were also reported being largely affected by the varying amount of post-recovery virus-induced Cardiac manifestations, in the subsequent waves of the pandemic. Therefore, here we thrived to find answers to the seemingly unending series of questions that popped up with the advent of the disease, nevertheless, there still lies a blind spot in understanding the impacts of the disease on the Cardiovascular Health of an individual, even after the clinical recovery. Thus, along with the current data related to the diverse cardiovascular complications due to SARS-COV-2 infection, we suggest long-term ‘Cardiac surveillance' for the COVID-19 recovered individuals.

Population Genetic Difference of Pharmacogenomic VIP Variants in the Tibetan Population

BACKGROUND

Genetic variation influences drug reaction or adverse prognosis. The purpose of this research was to genotype very important pharmacogenetic (VIP) variants in the Tibetan population.

METHODS AND MATERIALS

Blood samples from 200 Tibetans were randomly collected and 59 VIP variants were genotyped, and then compared our data to 26 other populations in the 1000 project to further analyze and identify significant difference.

RESULTS

The results showed that on comparing with most of the 26 populations from the 1000 project, rs4291 (ACE), rs1051296 (SLC19A1) and rs1065852 (CYP2D6) significantly differed in the Tibetan population. Furthermore, three significant loci were related to drug response. In addition, the allele frequency of Tibetans least differed from that of East Asian populations, and most differed from that of Americans.

CONCLUSION

Three significant loci of variation ACE rs4291, SLC19A1 rs1051296 and CYP2D6 rs1065852 were associated with drug response. This result will contribute to improving the information of the Tibetan in the pharmacogenomics database, and providing a theoretical basis for clinical individualised drug use in Tibetans.

SARS-CoV-2: is there neuroinvasion?

BACKGROUND

SARS-CoV-2, a coronavirus (CoV), is known to cause acute respiratory distress syndrome, and a number of non-respiratory complications, particularly in older male patients with prior health conditions, such as obesity, diabetes and hypertension. These prior health conditions are associated with vascular dysfunction, and the CoV disease 2019 (COVID-19) complications include multiorgan failure and neurological problems. While the main route of entry into the body is inhalation, this virus has been found in many tissues, including the choroid plexus and meningeal vessels, and in neurons and CSF.

MAIN BODY

We reviewed SARS-CoV-2/COVID-19, ACE2 distribution and beneficial effects, the CNS vascular barriers, possible mechanisms by which the virus enters the brain, outlined prior health conditions (obesity, hypertension and diabetes), neurological COVID-19 manifestation and the aging cerebrovascualture. The overall aim is to provide the general reader with a breadth of information on this type of virus and the wide distribution of its main receptor so as to better understand the significance of neurological complications, uniqueness of the brain, and the pre-existing medical conditions that affect brain. The main issue is that there is no sound evidence for large flux of SARS-CoV-2 into brain, at present, compared to its invasion of the inhalation pathways.

CONCLUSIONS

While SARS-CoV-2 is detected in brains from severely infected patients, it is unclear on how it gets there. There is no sound evidence of SARS-CoV-2 flux into brain to significantly contribute to the overall outcomes once the respiratory system is invaded by the virus. The consensus, based on the normal route of infection and presence of SARS-CoV-2 in severely infected patients, is that the olfactory mucosa is a possible route into brain. Studies are needed to demonstrate flux of SARS-CoV-2 into brain, and its replication in the parenchyma to demonstrate neuroinvasion. It is possible that the neurological manifestations of COVID-19 are a consequence of mainly cardio-respiratory distress and multiorgan failure. Understanding potential SARS-CoV-2 neuroinvasion pathways could help to better define the non-respiratory neurological manifestation of COVID-19.

Association of single-nucleotide polymorphism on chromosome 9 and ischemic stroke in Heilongjiang province in China

There is a significant correlation between ischemic stroke (IS) and chromosome 9. However, its status was uncertain in China's cold regions. 1920 IS patients, and 1920 healthy individuals were included in the study. Blood samples were collected. The association of SNPs with IS was evaluated by Sequenom, and logistic regression models adjusted for known risk factors of IS were constructed to assess the SNPs' associations in cases and controls. We found rs1333040 and rs2383207 were associated with IS, compared with primitive genotypes. The genotype CT of rs7027526 has a protective role during IS development, while the effect of the genotype TT is still not clear. These results changed after stratification by age and sex. In conclusion, rs1333040 and rs2383207 SNPs in CDKN2BAS are associated with ischemic stroke in the Chinese Han population. This study confirms the association between 9p21.3 and IS.

Role of ACE 2 and Vitamin D: The Two Players in Global Fight against COVID-19 Pandemic

The global pandemic of coronavirus disease 2019 (COVID-19) has spread across the borders, gaining attention from both health care professional and researchers to understand the mode of entry and actions induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), its causative agent in the human body. The role of angiotensin-converting enzyme–2 (ACE2) in facilitating the entry of the virus in the host cell by binding to it is similar to SARS-CoV-1, the causative agent for severe acute respiratory syndrome (SARS) which emerged in 2003. Besides the role of ACE2 as a molecular target for the virus, the review displays the potential benefits of ACE2 enzyme and various agents that modify its activity in curbing the effects of the deadly virus, thus unfolding a dual character of ACE2 in the current pandemic. As evident by the differences in the susceptibility toward viral infection in children and geriatric population, it must be noted that the older population has limited ACE2 levels and greater infection risk, whereas the situation is reversed in the case of the pediatric population, demonstrating the defensive character of ACE2 in the latter, despite acting as receptor target for SARS-CoV-2. Also, the upregulation of ACE2 levels by estrogen has indicated greater resistance to infection in females than in the male human population. ACE2 is a carboxypeptidase, which degrades angiotensin II and counteracts its actions to protect against cardiovascular risks associated with the virus. Another contribution of this enzyme is supported by the role of circulating soluble ACE2, which acts as a receptor to bind the virus but does not mediate its actions, therefore blocking its interaction to membrane-bound ACE2 receptors. The review also shares the enhanced risks of developing COVID-19 infection by using ACE inhibitors and ARBs. However, both these agents have been reported to upregulate ACE2 levels; yet, adequate evidence regarding their role is quite inconsistent in human studies. Furthermore, the role of vitamin D has been highlighted in regulating the immune system of the body through renin-angiotensin-aldosterone system (RAAS) inhibition, by downregulating host cell receptor expression to prevent virus attachment. Besides, vitamin D also acts through several other mechanisms like upregulating antimicrobial peptides, fighting against the proinflammatory milieu created by the invading virus, and interfering with the viral replication cycle as well as calcitriol-mediated blockage of CREB protein. Hypovitaminosis D is attributed to elevated risks of acute respiratory distress syndrome (ARDS), lung damage, and cardiovascular disorders, further increasing the severity of COVID-19 infection.

Genetic and epigenetic control of ACE2 expression and its possible role in COVID-19

Coronavirus disease 2019 (COVID‐19), caused by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), is a pandemic that is claiming hundreds of thousands of lives around the world. Angiotensin‐converting enzyme‐2 (ACE2) is a key player in COVID‐19 due to its pivotal role in the SARS‐CoV‐2 infection. This enzyme is expressed throughout the body and the studies conducted so far have shown that its expression varies according to several factors, including cell type, sex, age, disease states and probably SARS‐CoV‐2 infection. Single‐nucleotide polymorphisms (SNPs) and epigenetic mechanisms, including DNA methylation, histone post‐translational modifications and microRNAs, impact ACE2 expression and may explain structural variation. The understanding of how genetic variants and epigenetic markers act to control ACE2 expression in health and disease states may contribute to comprehend several aspects of COVID‐19 that are puzzling researchers and clinicians. This review collects and appraises the literature regarding some aspects in the ACE2 biology, the expression patterns of this molecule, SNPs of the ACE2 gene and epigenetic mechanisms that may impact ACE2 expression in the context of COVID‐19.

Disparities in COVID-19 severities and casualties across ethnic groups around the globe and patterns of ACE2 and PIR variants

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mediated Coronavirus disease-19 (COVID-19) has affected millions of individuals around all corners of the globe. Symptoms and severities of infection with this highly contagious virus vary among individuals and there is disparity in the number of COVID-19-related casualties across different ethnic groups. The primary receptor for SARS-CoV-2 entry into the host cells is angiotensin-converting enzyme 2 (ACE2). Certain variants of ACE2 are known to be associated with COVID-19 comorbidities such as hypertension, cardiovascular complications, diabetes, chronic lung disease, etc. In this study, we looked into the geographic distribution of disease-associated variants of ACE2 as well as closely located PIR gene to explore any possible correlation with the disparities in COVID-19 severities and casualties across ethnic groups. Frequencies of the ACE2 variants associated with COVID-19 comorbidities are higher in the European and the admixed American populations. These variants are also present with stronger pairwise linkage disequilibrium (LD) in the European and the admixed American populations. On the other hand, the variants with protective role are more prevalent in the East and the South Asian populations. Strong pairwise LD exists among the activity modifying (modifier) variants of the PIR and ACE2 genes only in the European super-population. Absence of these PIR variants in the South Asian population may contribute to the overall lower COVID-19 case fatality rates (CFR) despite the dense population in this region.

Why is COVID-19 less severe in children? A review of the proposed mechanisms underlying the age-related difference in severity of SARS-CoV-2 infections

In contrast to other respiratory viruses, children have less severe symptoms when infected with the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this review, we discuss proposed hypotheses for the age-related difference in severity of coronavirus disease 2019 (COVID-19).Factors proposed to explain the difference in severity of COVID-19 in children and adults include those that put adults at higher risk and those that protect children. The former include: (1) age-related increase in endothelial damage and changes in clotting function; (2) higher density, increased affinity and different distribution of angiotensin converting enzyme 2 receptors and transmembrane serine protease 2; (3) pre-existing coronavirus antibodies (including antibody-dependent enhancement) and T cells; (4) immunosenescence and inflammaging, including the effects of chronic cytomegalovirus infection; (5) a higher prevalence of comorbidities associated with severe COVID-19 and (6) lower levels of vitamin D. Factors that might protect children include: (1) differences in innate and adaptive immunity; (2) more frequent recurrent and concurrent infections; (3) pre-existing immunity to coronaviruses; (4) differences in microbiota; (5) higher levels of melatonin; (6) protective off-target effects of live vaccines and (7) lower intensity of exposure to SARS-CoV-2.

Germline Genetic Variants of Viral Entry and Innate Immunity May Influence Susceptibility to SARS-CoV-2 Infection: Toward a Polygenic Risk Score for Risk Stratification

The ongoing COVID-19 pandemic caused by the novel coronavirus, SARS-CoV-2 has affected all aspects of human society with a special focus on healthcare. Although older patients with preexisting chronic illnesses are more prone to develop severe complications, younger, healthy individuals might also exhibit serious manifestations. Previous studies directed to detect genetic susceptibility factors for earlier epidemics have provided evidence of certain protective variations. Following SARS-CoV-2 exposure, viral entry into cells followed by recognition and response by the innate immunity are key determinants of COVID-19 development. In the present review our aim was to conduct a thorough review of the literature on the role of single nucleotide polymorphisms (SNPs) as key agents affecting the viral entry of SARS-CoV-2 and innate immunity. Several SNPs within the scope of our approach were found to alter susceptibility to various bacterial and viral infections. Additionally, a multitude of studies confirmed genetic associations between the analyzed genes and autoimmune diseases, underlining the versatile immune consequences of these variants. Based on confirmed associations it is highly plausible that the SNPs affecting viral entry and innate immunity might confer altered susceptibility to SARS-CoV-2 infection and its complex clinical consequences. Anticipating several COVID-19 genomic susceptibility loci based on the ongoing genome wide association studies, our review also proposes that a well-established polygenic risk score would be able to clinically leverage the acquired knowledge.

Angiotensin-converting enzyme 2 and COVID-19: patients, comorbidities, and therapies

On March 11, 2020, the World Health Organization declared coronavirus disease 2019 (COVID-19) a pandemic, and the reality of the situation has finally caught up to the widespread reach of the disease. The presentation of the disease is highly variable, ranging from asymptomatic carriers to critical COVID-19. The availability of angiotensin-converting enzyme 2 (ACE2) receptors may reportedly increase the susceptibility and/or disease progression of COVID-19. Comorbidities and risk factors have also been noted to increase COVID-19 susceptibility. In this paper, we hereby review the evidence pertaining to ACE2's relationship to common comorbidities, risk factors, and therapies associated with the susceptibility and severity of COVID-19. We also highlight gaps of knowledge that require further investigation. The primary comorbidities of respiratory disease, cardiovascular disease, renal disease, diabetes, obesity, and hypertension had strong evidence. The secondary risk factors of age, sex, and race/genetics had limited-to-moderate evidence. The tertiary factors of ACE inhibitors and angiotensin II receptor blockers had limited-to-moderate evidence. Ibuprofen and thiazolidinediones had limited evidence.

ACE2 Nascence, trafficking, and SARS-CoV-2 pathogenesis: the saga continues

With the emergence of the novel coronavirus SARS-CoV-2 since December 2019, more than 65 million cases have been reported worldwide. This virus has shown high infectivity and severe symptoms in some cases, leading to over 1.5 million deaths globally. Despite the collaborative and concerted research efforts that have been made, no effective medication for COVID-19 (coronavirus disease-2019) is currently available. SARS-CoV-2 uses the angiotensin-converting enzyme 2 (ACE2) as an initial mediator for viral attachment and host cell invasion. ACE2 is widely distributed in the human tissues including the cell surface of lung cells which represent the primary site of the infection. Inhibiting or reducing cell surface availability of ACE2 represents a promising therapy for tackling COVID-19. In this context, most ACE2-based therapeutic strategies have aimed to tackle the virus through the use of angiotensin-converting enzyme (ACE) inhibitors or neutralizing the virus by exogenous administration of ACE2, which does not directly aim to reduce its membrane availability. However, through this review, we present a different perspective focusing on the subcellular localization and trafficking of ACE2. Membrane targeting of ACE2, and shedding and cellular trafficking pathways including the internalization are not well elucidated in literature. Therefore, we hereby present an overview of the fate of newly synthesized ACE2, its post translational modifications, and what is known of its trafficking pathways. In addition, we highlight the possibility that some of the identified ACE2 missense variants might affect its trafficking efficiency and localization and hence may explain some of the observed variable severity of SARS-CoV-2 infections. Moreover, an extensive understanding of these processes is necessarily required to evaluate the potential use of ACE2 as a credible therapeutic target.

Ramadan Fasting During the COVID-19 Pandemic; Observance of Health, Nutrition and Exercise Criteria for Improving the Immune System

Fasting is one of the religious rituals of Muslims worldwide who refrain from eating foods and liquids every year during Ramadan. This year (2020), Ramadan is very different from previous years due to the outbreak of a terrible microscopic giant called coronavirus disease 2019 (COVID-19). The pandemic COVID-19 has made Ramadan very important this year because the virus has infected millions of people around the world and killed thousands, especially people with immunodeficiency. In dealing with COVID-19, maintaining good hygiene and supporting the immune system are effective, preventive approaches. Moderate exercise training and proper nutrition are the most important factors to support immune function. Lack of facilities, poor health and many traditions that lead to public community gatherings have made many Islamic countries susceptible to this dangerous virus. In such an unprecedented situation, there are many Muslims who doubt whether they can fast or not. Therefore, the proposal of usable exercise programs and effective nutritional strategies is imperative. In this study, we will look at the proposed health effects of fasting and its impact on the immune system, the effects of Ramadan intermittent fasting on resting values and responses of immunological/antioxidant biomarkers in elite and recreational athletes, together with the important health, nutrition, and exercise advice that fasting people need to follow in the event of a COVID-19 outbreak.

Underlying Kidney Diseases and Complications for COVID-19: A Review

There is mounting evidence supporting that patients with kidney diseases are particularly vulnerable to coronavirus disease-2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The review was conducted to examine the risk and complications of COVID-19 among patients with confirmed cases of underlying kidney disease. A search of Google Scholar, PubMed and Science direct databases to August 2020 was conducted using search terms pertaining to kidney diseases, renal insufficiency, kidney injury, angiotensin receptors, hemodialysis, and kidney transplant. We briefly reviewed COVID-19 in the context of kidney diseases. A significant proportion of hospitalized patients for COVID-19 have acute kidney injury, which further deteriorates their prognosis. COVID-19 increases morbidity and mortality among people already diagnosed with kidney disorders and obesity due to multiple organ injury caused by the SARS-CoV-2. This review supports the need for clinicians to carefully manage and monitor all patients with renal disorders in order to minimize acute kidney injuries. Although some therapeutic drugs have been suggested by some studies, treatment should be administered cautiously not to worsen the condition of the kidney. Further studies are required to highlight the efficient management of patients with underlying kidney diseases, who are infected with SARS-CoV-2. With proactive systematic screening and triaging, close monitoring and prompt management of coexisting other infections, the COVID-19 disease burden among these patients could be reduced.

Variability in genes related to SARS-CoV-2 entry into host cells (ACE2, TMPRSS2, TMPRSS11A, ELANE, and CTSL) and its potential use in association studies

BACKGROUND

The prevalence and mortality of the outbreak of the COVID-19 pandemic show marked geographic variation. The presence of several subtypes of the coronavirus and the genetic differences in the populations could condition that variation. Thus, the objective of this study was to propose variants in genes that encode proteins related to the SARS-CoV-2 entry into the host cells as possible targets for genetic associations studies.

METHODS

The allelic frequencies of the polymorphisms in the ACE2, TMPRSS2, TMPRSS11A, cathepsin L (CTSL), and elastase (ELANE) genes were obtained in four populations from the American, African, European, and Asian continents reported in the 1000 Genome Project. Moreover, we evaluated the potential biological effect of these variants using different web-based tools.

RESULTS

In the coding sequences of these genes, we detected one probably-damaging polymorphism located in the TMPRSS2 gene (rs12329760) that produces a change of amino acid. Furthermore, forty-eight polymorphisms with possible functional consequences were detected in the non-coding sequences of the following genes: three in ACE2, seventeen in TMPRSS2, ten in TMPRSS11A, twelve in ELANE, and six in CTSL. These polymorphisms produce binding sites for transcription factors and microRNAs. The minor allele frequencies of these polymorphisms vary in each community; indeed, some of them are high in specific populations.

CONCLUSION

In summary, using data of the 1000 Genome Project and web-based tools, we propose some polymorphisms, which, depending on the population, could be used for genetic association studies.

Allele Frequency of ACE2 Intron Variants and Its Association with Blood Pressure

Angiotensin-converting enzyme 2 (ACE2) is known as the counter-regulator of the renin-angiotensin system, it cleaves angiotensin II to render Ag 1-7, a potent vasodilator with multiple roles in cardiovascular protection. A few studies have pinpointed ACE2 polymorphisms and their relationship with heart function and hypertension in a sex-dependent manner. These observations still lack replication mostly for admixed populations. This study aimed to report minor allele frequencies of four ACE2 intron variants, rs2285666, rs2048683, rs2106809, and rs4240157, derived from previous research using the GSA, v1.0, microarray in 1231 hypertensive and nonhypertensive patients. Logistic and multiple linear regression models were developed to identify potential associations with hypertension status and systolic and diastolic blood pressure (SBP and DBP). Allele frequency differences were identified for ACE2 rs2048683 and rs4240157 in populations with European ancestry and people of the Americas. Regression analyses identified a significant association of ACE2 rs2048683 and rs4240157 with SBP/DBP in males or females. Our observations confirm sex differences in ACE2 genetic associations with SBP and DBP and contribute to the collection of genetic variation in ACE2 for admixed populations.

Plasma ACE2 and risk of death or cardiometabolic diseases: a case-cohort analysis

BACKGROUND

Angiotensin-converting enzyme 2 (ACE2) is an endogenous counter-regulator of the renin-angiotensin hormonal cascade. We assessed whether plasma ACE2 concentrations were associated with greater risk of death or cardiovascular disease events.

METHODS

We used data from the Prospective Urban Rural Epidemiology (PURE) prospective study to conduct a case-cohort analysis within a subset of PURE participants (from 14 countries across five continents: Africa, Asia, Europe, North America, and South America). We measured plasma concentrations of ACE2 and assessed potential determinants of plasma ACE2 levels as well as the association of ACE2 with cardiovascular events.

FINDINGS

We included 10 753 PURE participants in our study. Increased concentration of plasma ACE2 was associated with increased risk of total deaths (hazard ratio [HR] 1·35 per 1 SD increase [95% CI 1·29-1·43]) with similar increases in cardiovascular and non-cardiovascular deaths. Plasma ACE2 concentration was also associated with higher risk of incident heart failure (HR 1·27 per 1 SD increase [1·10-1·46]), myocardial infarction (HR 1·23 per 1 SD increase [1·13-1·33]), stroke (HR 1·21 per 1 SD increase [1·10-1·32]) and diabetes (HR 1·44 per 1 SD increase [1·36-1·52]). These findings were independent of age, sex, ancestry, and traditional cardiac risk factors. With the exception of incident heart failure events, the independent relationship of ACE2 with the clinical endpoints, including death, remained robust after adjustment for BNP. The highest-ranked determinants of ACE2 concentrations were sex, geographic ancestry, and body-mass index (BMI). When compared with clinical risk factors (smoking, diabetes, blood pressure, lipids, and BMI), ACE2 was the highest ranked predictor of death, and superseded several risk factors as a predictor of heart failure, stroke, and myocardial infarction.

INTERPRETATION

Increased plasma ACE2 concentration was associated with increased risk of major cardiovascular events in a global study.

FUNDING

Canadian Institute of Health Research, Heart & Stroke Foundation of Canada, and Bayer.

Analysis of the Spectrum of ACE2 Variation Suggests a Possible Influence of Rare and Common Variants on Susceptibility to COVID-19 and Severity of Outcome

OBJECTIVES

In March 2020, the World Health Organization declared that an infectious respiratory disease caused by a new severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2, causing coronavirus disease 2019 (COVID-19)] became a pandemic. In our study, we have analyzed a large publicly available dataset, the Genome Aggregation Database (gnomAD), as well as a cohort of 37 Russian patients with COVID-19 to assess the influence of different classes of genetic variants in the angiotensin-converting enzyme-2 (ACE2) gene on the susceptibility to COVID-19 and the severity of disease outcome.

RESULTS

We demonstrate that the European populations slightly differ in alternative allele frequencies at the 2,754 variant sites in ACE2 identified in the gnomAD database. We find that the Southern European population has a lower frequency of missense variants and slightly higher frequency of regulatory variants. However, we found no statistical support for the significance of these differences. We also show that the Russian population is similar to other European populations when comparing the frequencies of the ACE2 variants. Evaluation of the effect of various classes of ACE2 variants on COVID-19 outcome in a cohort of Russian patients showed that common missense and regulatory variants do not explain the differences in disease severity. At the same time, we find several rare ACE2 variants (including rs146598386, rs73195521, rs755766792, and others) that are likely to affect the outcome of COVID-19. Our results demonstrate that the spectrum of genetic variants in ACE2 may partially explain the differences in severity of the COVID-19 outcome.

Genetic Association of ACE2 rs2285666 Polymorphism With COVID-19 Spatial Distribution in India

Studies on host-pathogen interaction have identified human ACE2 as a host cell receptor responsible for mediating infection by coronavirus (COVID-19). Subsequent studies have shown striking difference of allele frequency among Europeans and Asians for a polymorphism rs2285666, present in ACE2. It has been revealed that the alternate allele (TT-plus strand or AA-minus strand) of rs2285666 elevate the expression level of this gene upto 50%, hence may play a significant role in SARS-CoV-2 susceptibility. Therefore, we have first looked the phylogenetic structure of rs2285666 derived haplotypes in worldwide populations and compared the spatial frequency of this particular allele with respect to the COVID-19 infection as well as case-fatality rate in India. For the first time, we ascertained a significant positive correlation for alternate allele (T or A) of rs2285666, with the lower infection as well as case-fatality rate among Indian populations. We trust that this information will be useful to understand the role of ACE2 in COVID-19 susceptibility.

Severe COVID-19: what have we learned with the immunopathogenesis?

The COVID-19 outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global major concern. In this review, we addressed a theoretical model on immunopathogenesis associated with severe COVID-19, based on the current literature of SARS-CoV-2 and other epidemic pathogenic coronaviruses, such as SARS and MERS. Several studies have suggested that immune dysregulation and hyperinflammatory response induced by SARS-CoV-2 are more involved in disease severity than the virus itself.Immune dysregulation due to COVID-19 is characterized by delayed and impaired interferon response, lymphocyte exhaustion and cytokine storm that ultimately lead to diffuse lung tissue damage and posterior thrombotic phenomena.Considering there is a lack of clinical evidence provided by randomized clinical trials, the knowledge about SARS-CoV-2 disease pathogenesis and immune response is a cornerstone to develop rationale-based clinical therapeutic strategies. In this narrative review, the authors aimed to describe the immunopathogenesis of severe forms of COVID-19.

COVID-19 Infection and Children: A Comprehensive Review

Nowadays, COVID-19 is in pandemic stage, and concerns about the infection of children are on the rise. At first, it has been believed that children are not at risk while some evidences have shown that the risk of infection is lower in children than adults. The COVID-19 children indicated milder symptoms including cough, fever, sore throat, myalgia sneezing, and fatigue than COVID-19 adults. Lymphopenia, which is prevalent in adult cases, has not been reported in pediatric patients. The COVID-19 can also occur in neonates although vertical transmission from mothers to fetuses during pregnancy is rare. Overall, the outcome is better in children than adults. Thus far, there has been neither specific treatment for eradicating the infection nor any preventative vaccine for COVID-19, Preventive measures such as frequent hand washing, social distancing and wearing face mask are the best ways.

Sex differences in severity and mortality from COVID-19: are males more vulnerable?

Coronavirus disease 2019 (COVID-19) has shown high infection and mortality rates all over the world, and despite the global efforts, there is so far no specific therapy available for COVID-19. Interestingly, while the severity and mortality of COVID-19 are higher in males than in females, the underlying molecular mechanisms are unclear. In this review, we explore sex-related differences that may be contributing factors to the observed male-biased mortality from COVID-19. Males are considered the weaker sex in aspects related to endurance and infection control. Studies show that viral RNA clearance is delayed in males with COVID-19. A recent study has indicated that the testis can harbor coronavirus, and consequently, males show delayed viral clearance. However, the role of testis involvement in COVID-19 severity and mortality needs further research. Males and females show a distinct difference in immune system responses with females eliciting stronger immune responses to pathogens. This difference in immune system responses may be a major contributing factor to viral load, disease severity, and mortality. In addition, differences in sex hormone milieus could also be a determinant of viral infections as estrogen has immunoenhancing effects while testosterone has immunosuppressive effects. The sex-specific severity of COVID-19 infections indicates that further research on understanding the sex differences is needed. Inclusion of both males and females in basic research and clinical trials is required to provide critical information on sex-related differences that may help to better understand disease outcome and therapy.

The dual impact of ACE2 in COVID-19 and ironical actions in geriatrics and pediatrics with possible therapeutic solutions

The novel corona virus disease has shaken the entire world with its deadly effects and rapid transmission rates, posing a significant challenge to the healthcare authorities to develop suitable therapeutic solution to save lives on earth. The review aims to grab the attention of the researchers all over the globe, towards the role of ACE2 in COVID-19 disease. ACE2 serves as a molecular target for the SARS-CoV-2, to enter the target cell, by interacting with the viral glycoprotein spikes. However, the complexity began when numerous studies identified the protective response of ACE2 in abbreviating the harmful effects of vasoconstrictor, anti-inflammatory peptide, angiotensin 2, by mediating its conversion to angiotensin-(1-7), which exercised antagonistic actions to angiotensin 2. Furthermore, certain investigations revealed greater resistance among children as compared to the geriatrics, towards COVID-19 infection, despite the elevated expression of ACE2 in pediatric population. Based upon such evidences, the review demonstrated possible therapeutic interventions, targeting both the protective and deleterious effects of ACE2 in COVID-19 disease, primarily inhibiting ACE2-virus interactions or administering soluble ACE2. Thus, the authors aim to provide an opportunity for the researchers to consider RAAS system to be a significant element in development of suitable treatment regime for COVID-19 pandemic.

The Two Faces of ACE2: The Role of ACE2 Receptor and Its Polymorphisms in Hypertension and COVID-19

The mechanism for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection requires the binding of the virus to the angiotensin-converting enzyme 2 (ACE2) receptor, well-known for its role in counteracting ACE. ACE2 is involved in modulating blood pressure and establishing blood pressure homeostasis. Recently, a critical debatable question has arisen whether using antihypertensive medications will have a favorable impact on people infected with SARS-CoV-2 or a deleterious one, mainly because angiotensin-converting enzyme inhibitor (ACEI) and angiotensin-receptor blocker (ARB) therapy can modulate the expression of ACE2 protein. The concern is that the use of ACEIs and ARBs will increase the expression of ACE2 and increase patient susceptibility to viral host cell entry and propagation. On the other hand, several genetic association studies have examined the relationship between ACE2 genetic variants and the risk of developing hypertension in different ethnic populations. In this review, we discuss the ongoing arguments in the literature about ACE2's role in mortality rate among coronavirus disease 2019 (COVID-19) patients comorbid with hypertension and critically evaluate the current debate about the usage or discontinuation of ACEI/ARB antihypertensive drugs. Moreover, we explore the two opposing roles that ACE2 genetic variants might be playing in COVID-19 by reducing ACE2 receptor effectiveness and mitigating SARS-CoV-2 infectivity.

Association of ACE2 receptor and ACEIs/ARBs with disease severity in COVID-19

Coronavirus disease 2019 (COVID-19) is found to be associated with various comorbidities which include cardiovascular diseases, hypertension, and diabetes. The impaired regulation of renin-angiotensin-aldosterone system (RAAS) has been seen in COVID-19 patients, but whether RAAS inhibitors, such as angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs), are responsible for worsening of clinical conditions remains unknown. Herein, we review the role of angiotensin-converting enzyme 2 (ACE2) expression in disease progression, its association with comorbidities and COVID-19, and summarize the clinical evidence for several potential directions for future research work on ACEIs/ARBs in COVID-19 patients.

Angiotensin-converting enzymes (ACE, ACE2) gene variants and COVID-19 outcome

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The Angiotensin system has been implicated in the pathogenesis of COVID-19.

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Functional ACE/ACE2 polymorphisms might contribute to the outcome of COVID-19.

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Severe COVID-19 was associated with hypertension, male gender, and ACE-DD genotype.

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The ACE2 polymorphism was not associated with the disease outcome.

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ACE2 showed no coding variants that could explain an increased risk of COVID-19.

The Angiotensin system is implicated in the pathogenesis of COVID-19. First, ACE2 is the cellular receptor for SARS-CoV-2, and expression of the ACE2 gene could regulate the individuaĺs susceptibility to infection. In addition, the balance between ACE1 and ACE2 activity has been implicated in the pathogenesis of respiratory diseases and could play a role in the severity of COVID-19. Functional ACE1/ACE2 gene polymorphisms have been associated with the risk of cardiovascular and pulmonary diseases, and could thus also contribute to the outcome of COVID-19.

We studied 204 COVID-19 patients (137 non-severe and 67 severe-ICU cases) and 536 age-matched controls. The ACE1 insertion/deletion and ACE2 rs2285666 polymorphism were determined. Variables frequencies were compared between the groups by logistic regression. We also sequenced the ACE2 coding nucleotides in a group of patients.

Severe COVID-19 was associated with hypertension male gender (p < 0.001), hypertension (p = 0.006), hypercholesterolaemia (p = 0.046), and the ACE1-DD genotype (p = 0.049). In the multiple logistic regression hypertension (p = 0.02, OR = 2.26, 95%CI = 1.12–4.63) and male gender (p = 0.002; OR = 3.15, 95%CI = 1.56–6.66) remained as independent significant predictors of severity. The ACE2 polymorphism was not associated with the disease outcome. The ACE2 sequencing showed no coding sequence variants that could explain an increased risk of developing COVID-19.

In conclusion, an adverse outcome of COVID-19 was associated with male gender, hypertension, hypercholesterolemia and the ACE1 genotype. Our work suggested that the ACE1-I/D might influence COVID-19 severity, but the effect was dependent on the hypertensive status. This result requires further validation in other large cohorts.

Two important controversial risk factors in SARS-CoV-2 infection: Obesity and smoking

The effects of obesity and smoking in the coronavirus disease 2019 (COVID-19) pandemic remain controversial. Angiotensin converting enzyme 2 (ACE2), a component of the renin-angiotensin system (RAS), is the human cell receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. ACE2 expression increases on lung alveolar epithelial cells and adipose tissue due to obesity, smoking and air pollution. A significant relationship exists between air pollution and SARS-CoV-2 infection, as more severe COVID-19 symptoms occur in smokers; comorbid conditions due to obesity or excess ectopic fat accumulation as underlying risk factors for severe COVID-19 strongly encourage the virus/ACE2 receptor-ligand interaction concept. Indeed, obesity, air pollution and smoking associated risk factors share underlying pathophysiologies that are related to the Renin-Angiotensin-System in SARS-CoV-2 infection. The aim of this review is to emphasize the mechanism of receptor-ligand interaction and its impact on the enhanced risk of death due to SARS-CoV-2 infection.