Angiotensin converting enzyme: A review on expression profile and its association with human disorders with special focus on SARS-CoV-2 infection

Persicaria minor (Huds.) Opiz Exhibits Antihypertensive Effects by Inhibiting the Angiotensin-Converting Enzyme/Angiotensin II Type 1 Receptor Pathway in Human Endothelial Cells

Overactivation of the angiotensin-converting enzyme (ACE)/angiotensin II type 1 receptor (AT1R) pathway leads to vasoconstriction and elevated blood pressure. Persicaria minor (Huds.) Opiz is an herbal plant known for its antioxidant, anti-hyperlipidemic, and anti-atherosclerotic properties, with bioactive compounds that exhibit antihypertensive effects. Therefore, this study aimed to evaluate the antihypertensive effects of the standardized aqueous extract of P. minor leaf (AEPM) through the ACE/AT1R pathway in human umbilical vein endothelial cells (HUVECs) induced with phorbol 12-myristate 13-acetate (PMA). HUVECs were stimulated with PMA to induce ACE, with or without AEPM or captopril treatment, for 24 h. Subsequently, ACE mRNA expression, ACE protein levels, ACE activity, angiotensin II levels, and AT1R expression were measured. The results demonstrated that AEPM treatment significantly reduced ACE mRNA expression, ACE protein levels, ACE activity, angiotensin II levels, and AT1R expression in PMA-induced HUVECs. The modulatory effects of AEPM on the ACE/AT1R pathway were comparable to those of captopril. Ex vivo experiments further confirmed that AEPM reduced the contraction responses of rat aortic rings to PMA. In conclusion, P. minor effectively inhibits the ACE/AT1R pathway in PMA-induced HUVECs, suggesting its potential as a natural antihypertensive agent.

Renin-Angiotensin System Genes Polymorphisms in Patients With COVID-19 and Its Relation to Severe Cases of SARS-CoV-2 Infection

Background

Different variants of single nucleotide polymorphisms (SNPs) of angiotensinogen (AGT), angiotensin-converting enzyme type 1 (ACE1), and angiotensin II receptors type 1 (AGTR1) and 2 (AGTR2) genes determine different susceptibility to cardiovascular disease (CVD) and hypertension, which can be considered as risk factors for fatal outcomes among coronavirus disease 2019 (COVID-19) patients. The objective of our study was to assess the relation between the frequency of SNPs of the renin-angiotensin system (RAS) components, and the severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Methods

The cross-sectional study included 100 patients with a laboratory-confirmed diagnosis of COVID-19 admitted to the hospital. Criteria for severe COVID-19 included respiratory rate (RR) > 30/min, blood oxygen saturation (SpO2) ≤ 93%, signs of unstable hemodynamics with systolic blood pressure (SBP) < 90 and/or diastolic blood pressure (DBP) < 60 mm Hg. All patients were identified with alleles and genotypes of the polymorphic markers rs4762 of the AGT gene, rs1799752 of the ACE1 gene, rs5186 of the AGTR1 gene and rs1403543 of the AGTR2 gene using the polymerase chain reaction method in human DNA preparations on real-time CFX96C1000 Touch, Bio-Rad equipment (Syntol, Russia). Statistical analysis was performed in R v.4.2.

Results

Patients were divided into groups with severe (n = 44) and moderate COVID-19 (n = 56). For ACE1 rs1799752, a significant deviation from the population distribution was detected in both studied subgroups. A higher frequency of the C allele SNP rs5186 AGTR1 gene was detected in the group with severe disease. More frequent A/A genotype of SNP rs1403543 AGTR2 was detected among females with severe COVID-19. Haplotype analysis revealed more common DCG haplotype among patients with severe COVID-19. The odds ratio for severe COVID-19 in the presence of the DCG haplotype was 3.996 (95% confidential interval: 1.080 -14.791, P < 0.05).

Conclusions

Our data suggest that the SNP genes of the RAS components, may allow to identify groups of patients predisposed to a more severe course of COVID-19.

Interplay of TLR4 and SARS-CoV-2: Unveiling the Complex Mechanisms of Inflammation and Severity in COVID-19 Infections

The late 2019 emergence of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, caused profound and unprecedented disruption to the global socio-economic structure, negatively affecting millions of lives worldwide. A typical hallmark of severe COVID-19 is hyper inflammation due to aberrant cytokine release (cytokine storm) by innate immune cells. Recent studies have revealed that SARS-CoV-2, through its spike (S) protein, can activate the body's innate immune cells via Toll-Like Receptors (TLRs), particularly TLR4. In silico studies have demonstrated that the S protein binds with high affinity to TLR4, triggering downstream signaling processes that result in pro-inflammatory cytokine release. Compared to other TLRs, such as TLR2, TLR4 plays a more significant role in initiating and sustaining the inflammatory response associated with severe COVID-19. Furthermore, interactions between the virus and target cells can enhance the cellular expression of TLR4, making cells more susceptible to viral interactions and subsequent inflammation. This increased expression of TLR4 upon viral entry creates a feedback loop, where heightened TLR4 levels lead to amplified inflammatory responses, contributing to the severity of the disease. Additionally, TLR4's potent activation of inflammatory pathways sets it apart from other TLRs, underscoring its pivotal role in the pathogenesis of COVID-19. In this review, we thoroughly explore the multitude of regulatory signaling pathways that SARS-CoV-2 employs to incite inflammation. We specifically focus on the critical impact of TLR4 activation compared to other TLRs, highlighting how TLR4's interactions with the viral S protein can exacerbate the severity of COVID-19. By delving into the mechanisms of TLR4-mediated inflammation, we aim to shed light on potential therapeutic targets that could mitigate the inflammatory damage caused by severe COVID-19. Understanding the unique role of TLR4 in the context of SARS-CoV-2 infection could pave the way for novel treatment strategies that specifically inhibit this receptor's activity, thereby reducing the overall disease burden and improving patient outcomes.

Dabsylated Bradykinin Is Cleaved by Snake Venom Proteases from Echis ocellatus

The vasoactive peptide bradykinin (BK) is an important member of the renin-angiotensin system. Its discovery is tightly interwoven with snake venom research, because it was first detected in plasma following the addition of viper venom. While the fact that venoms liberate BK from a serum globulin fraction is well described, its destruction by the venom has largely gone unnoticed. Here, BK was found to be cleaved by snake venom metalloproteinases in the venom of Echis ocellatus, one of the deadliest snakes, which degraded its dabsylated form (DBK) in a few minutes after Pro7 (RPPGFSP↓FR). This is a common cleavage site for several mammalian proteases such as ACE, but is not typical for matrix metalloproteinases. Residual protease activity < 5% after addition of EDTA indicated that DBK is also cleaved by serine proteases to a minor extent. Mass spectrometry-based protein analysis provided spectral proof for several peptides of zinc metalloproteinase-disintegrin-like Eoc1, disintegrin EO4A, and three serine proteases in the venom.

Demonstration of the impact of COVID-19 on metabolic associated fatty liver disease by bioinformatics and system biology approach

BACKGROUND

Severe coronavirus disease 2019 (COVID-19) has caused a great threat to human health. Metabolic associated fatty liver disease (MAFLD) is a liver disease with a high prevalence rate. Previous studies indicated that MAFLD led to increased mortality and severe case rates of COVID-19 patients, but its mechanism remains unclear.

METHODS

This study analyzed the transcriptional profiles of COVID-19 and MAFLD patients and their respective healthy controls from the perspectives of bioinformatics and systems biology to explore the underlying molecular mechanisms between the 2 diseases. Specifically, gene expression profiles of COVID-19 and MAFLD patients were acquired from the gene expression omnibus datasets and screened shared differentially expressed genes (DEGs). Gene ontology and pathway function enrichment analysis were performed for common DEGs to reveal the regulatory relationship between the 2 diseases. Besides, the hub genes were extracted by constructing a protein-protein interaction network of shared DEGs. Based on these hub genes, we conducted regulatory network analysis of microRNA/transcription factors-genes and gene - disease relationship and predicted potential drugs for the treatment of COVID-19 and MAFLD.

RESULTS

A total of 3734 and 589 DEGs were screened from the transcriptome data of MAFLD (GSE183229) and COVID-19 (GSE196822), respectively, and 80 common DEGs were identified between COVID-19 and MAFLD. Functional enrichment analysis revealed that the shared DEGs were involved in inflammatory reaction, immune response and metabolic regulation. In addition, 10 hub genes including SERPINE1, IL1RN, THBS1, TNFAIP6, GADD45B, TNFRSF12A, PLA2G7, PTGES, PTX3 and GADD45G were identified. From the interaction network analysis, 41 transcription factors and 151 micro-RNAs were found to be the regulatory signals. Some mental, Inflammatory, liver diseases were found to be most related with the hub genes. Importantly, parthenolide, luteolin, apigenin and MS-275 have shown possibility as therapeutic agents against COVID-19 and MAFLD.

CONCLUSION

This study reveals the potential common pathogenesis between MAFLD and COVID-19, providing novel clues for future research and treatment of MAFLD and severe acute respiratory syndrome coronavirus 2 infection.

Metformin in SARS-CoV-2 infection: A hidden path - from altered inflammation to reduced mortality. A review from the literature

SARS-CoV-2 infection has been a major threat to human health and a huge challenge to Medicine. In only two years, COVID-19 affected >350 million people, causing >5.6 million deaths. Chronic inflammatory states, such as diabetes or obesity, are known risk factors for COVID-19 poorest outcomes, with higher risk for disease severity and greater mortality. Metformin remains on the first line of the management of hyperglycemia in type 2 diabetes. Through its anti-inflammatory and immunomodulatory mechanisms, metformin appears as an opportunity to control the dysregulated cytokine storm secondary to SARS-CoV-2 infection. Recent studies point towards a potential protective role of metformin in the course of COVID-19, showing that current or previous treatment with metformin associates with better outcomes.

Performance of Serum Angiotensin-Converting Enzyme in Diagnosing Sarcoidosis and Predicting the Active Status of Sarcoidosis: A Meta-Analysis

The usefulness of serum angiotensin-converting enzyme (sACE) for diagnosing sarcoidosis and determining the active status of sarcoidosis has been reported with varying outcomes. On the basis of the majority of published data, we conducted a meta-analysis to calculate the overall predictive accuracy of sACE in sarcoidosis disease and the active status of sarcoidosis. The inclusion of related research listed in Web of Science, PubMed, Scopus, and other literature databases was assessed. SROC curves were generated to characterize the overall test results after data on sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were combined. Publication bias was identified using Deeks’ funnel plot. Thirty-five publications with 8645 subjects met the inclusion criteria. The following are summary estimates of sACE diagnostic performance for sarcoidosis: sensitivity, 60% (95% confidence interval (CI), 52–68%); specificity, 93% (95% CI, 88–96%); PLR, 8.4 (95% CI, 5.3–13.3); NLR, 0.43 (95% CI, 0.36–0.52); and DOR, 19 (95% CI, 12–31). The area under the SROC curve (AUC) was 0.84 (95% CI, 0.80–0.87). Summary estimates for predicting the active status of sarcoidosis were as follows: sensitivity, 0.76 (95% CI, 0.61–0.87); specificity, 0.80 (95% CI, 0.64–0.90); PLR, 3.9 (95% CI, 2.1–7.3); NLR, 0.29 (95% CI, 0.17–0.49); and DOR, 13 (95% CI, 6–31). The AUC was 0.85 (95% CI, 0.82–0.88). There was no evidence of publication bias. Our meta-analysis suggests that measuring the sACE may assist in the diagnosis of sarcoidosis and predicting the active status of sarcoidosis, but the interpretation of the sACE results should be with caution. Future studies should validate our results.

Association analysis and expression level of ace polymorphisms with egg-laying trait in Taihang chicken

The number of egg-laying is an important indicator of reproduction performance in poultry breeding. To investigate the relationship between the function of Angiotensin-converting enzyme (ACE) and egg-laying performance of Taihang chicken, the mRNA and protein expression and single nucleotide polymorphism (SNP) of ACE were detected. Analysis of ACE bioinformatics and association analysis of polymorphisms were then performed. The polymorphisms analysis of ACE showed that three SNP loci (g.5066812A>C, g.5080076G>A, and g.5072728A>G) were detected in 800 Taihang chickens with egg-laying records. Association analysis of egg-laying found that ACE g.5066812A>C mutation was significantly associated with the egg-laying performance of Taihang chickens (P < 0.05), and the individuals with the g.5066812A>C mutation showed significantly increasing egg-laying. The mRNA expression was significantly higher in individuals with the AA genotype mutation than those with the AC and CC genotypes (P < 0.01), and the expression of ACE protein levels was consistent with the mRNA expression. Bioinformatics analysis indicated that these mutations affected the secondary and tertiary structure of ACE. This study provides new insights into ACE affecting chicken egg production and some basis for improving the egg production rate of Taihang chickens.

Angiotensin-converting enzyme 2 rs2285666 polymorphism and clinical parameters as the determinants of COVID-19 severity in Iranian population

Host genetic factors may be correlated with the severity of coronavirus disease 2019 (COVID-19). Angiotensin-converting enzyme 2 (ACE2) plays a vital role in viral cell entrance. The current study aimed to evaluate the association of ACE2 rs2285666 polymorphism and clinical parameters with COVID-19 mortality. The ACE2 rs2285666 polymorphism was genotyped using the polymerase chain reaction-restriction fragment length polymorphism in 556 recovered and 522 dead patients. In this study, the frequency of ACE2 rs2285666 CC was significantly higher than TT genotype in dead patients. The multivariate logistic regression analysis results showed that the higher levels of alanine aminotransferase, alkaline phosphatase, creatinine, erythrocyte sedimentation rate, and C-reactive protein and the low levels of uric acid, cholesterol, low density lipoprotein, 25-hydroxyvitamin D, real-time PCR Ct values, and ACE2 rs2285666 CC genotype were associated with increased mortality rates after COVID-19. In conclusion, our findings demonstrated a possible link between COVID-19 mortality, clinical parameters, and ACE2 rs2285666 CC. Further research is required to confirm these results.

Investigation of maternal and perinatal outcome in a population of Iranian pregnant women infected with COVID-19

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in pregnant women might affect both maternal and neonatal outcomes. Based on the inconsistency between the results of the previous studies and the lack of data about the possible vertical transmission of SARS-CoV-2, we designed the present study to investigate the maternal and perinatal outcomes in 182 Iranian pregnant women infected with COVID-19. Among 40 PCR tests conducted on neonatal throat samples, 11 tests were positive. Among the assessed women, 22 women needed ICU admission and 30 premature labors occurred. There were significant associations between ICU admission and many parameters such as the presence of dyspnea (P < 0.001), COVID-19-related CT scan findings (P = 0.003), need for a ventilator (P < 0.001), and low O₂ saturation (P < 0.001), all of which indicate the critical situation of patients. Notably, the cause of delivery was significantly different in both groups, with labor pain and fetal distress being the most frequent causes of delivery in non-ICU and ICU-admitted patients, respectively. Moreover, delivery route (P = 0.003), frequencies of IUGR (P = 0.042), neonatal death (P = 0.008) and asphyxia (P = 0.016), Apgar score (P = 0.003), and gestational age at delivery (P = 0.009) have been associated with ICU admission. The present investigation exhibits association between the critical situation of pregnant women affected with COVID-19 and some adverse neonatal outcomes.

COVID-19: The question of genetic diversity and therapeutic intervention approaches

Coronavirus disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2), is the largest pandemic in modern history with very high infection rates and considerable mortality. The disease, which emerged in China's Wuhan province, had its first reported case on December 29, 2019, and spread rapidly worldwide. On March 11, 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a pandemic and global health emergency. Since the outbreak, efforts to develop COVID-19 vaccines, engineer new drugs, and evaluate existing ones for drug repurposing have been intensively undertaken to find ways to control this pandemic. COVID-19 therapeutic strategies aim to impair molecular pathways involved in the virus entrance and replication or interfere in the patients' overreaction and immunopathology. Moreover, nanotechnology could be an approach to boost the activity of new drugs. Several COVID-19 vaccine candidates have received emergency-use or full authorization in one or more countries, and others are being developed and tested. This review assesses the different strategies currently proposed to control COVID-19 and the issues or limitations imposed on some approaches by the human and viral genetic variability.

Potential Genes Associated with COVID-19 and Comorbidity

Hypertension, diabetes mellitus, and coronary artery disease are common comorbidities and dangerous factors for infection and serious COVID-19. Polymorphisms in genes associated with comorbidities may help observe susceptibility and disease severity variation. However, specific genetic factors and the extent to which they can explain variation in susceptibility of severity are unclear. Therefore, we evaluated candidate genes associated with COVID-19 and hypertension, diabetes mellitus, and coronary artery disease. In particular, we performed searches against OMIM, NCBI, and other databases, protein-protein interaction network construction, and GO and KEGG pathway enrichment analyses. Results showed that the associated overlapping genes were TLR4, NLRP3, MBL2, IL6, IL1RN, IL1B, CX3CR1, CCR5, AGT, ACE, and F2. GO and KEGG analyses yielded 302 GO terms (q < 0.05) and 29 signaling pathways (q < 0.05), respectively, mainly including coronavirus disease-COVID-19 and cytokine-cytokine receptor interaction. IL6 and AGT were central in the PPI, with 8 and 5 connections, respectively. In this study, we identified 11 genes associated with both COVID-19 and three comorbidities that may contribute to infection and disease severity. The key genes IL6 and AGT are involved in regulating immune response, cytokine activity, and viral infection. Therefore, RAAS inhibitors, AGT antisense nucleotides, cytokine inhibitors, vitamin D, fenofibrate, and vaccines regulating non-immune and immune factors could be potential strategies to prevent and cure COVID-19. The study provides a basis for further investigation of genes and pathways with predictive value for the risk of infection and prognosis and could help guide drug and vaccine development to improve treatment efficacy and the development of personalised treatments, especially for COVID-19 individuals with common comorbidities.

Host Manipulation Mechanisms of SARS-CoV-2

Viruses are the simplest of pathogens, but possess sophisticated molecular mechanisms to manipulate host behavior, frequently utilizing molecular mimicry. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to bind to the host receptor neuropilin-1 in order to gain entry into the cell. To do this, the virus utilizes its spike protein polybasic cleavage site (PCS), which mimics the CendR motif of neuropilin-1's endogenous ligands. In addition to facilitating cell entry, binding to neuropilin-1 has analgesic effects. We discuss the potential impact of neuropilin-1 binding by SARS-CoV-2 in ameliorating sickness behavior of the host, and identify a convergent evolutionary strategy of PCS cleavage and subsequent neuropilin binding in other human viruses. In addition, we discuss the evolutionary leap of the ancestor of SARS-COV-2, which involved acquisition of the PCS thus faciliting binding to the neuropilin-1 receptor. Acquisition of the PCS by the ancestor of SARS-CoV-2 appears to have led to pleiotropic beneficial effects including enhancement of cell entry via binding to ACE2, facilitation of cell entry via binding to neuropilin-1, promotion of analgesia, and potentially the formation of decoy epitopes via enhanced shedding of the S1 subunit. Lastly, other potential neuromanipulation strategies employed by SARS-CoV-2 are discussed, including interferon suppression and the resulting reduction in sickness behavior, enhanced transmission through neurally mediated cough induction, and reduction in sense of smell.

Abnormal Transcript Levels of Cytokines Among Iranian COVID-19 Patients

The pandemic caused by severe acute respiratory syndrome coronavirus 2 and the related disorder i.e. “coronavirus disease 2019” (COVID-19) has encouraged researchers to unravel the molecular mechanism of disease severity. Several lines of evidence support the impact of “cytokine storm” in the pathogenesis of severe forms of the disorder. We aimed to assess expression levels of nine cytokine coding genes in COVID-19 patients admitted in a hospital. We collected clinical data of patients from their medical reports. Then, we assessed expression of genes using real-time PCR. Expression levels of IFN-G, IL-2, IL-4, IL-6, IL-17, TGF-B, IL-8, and IL-1B were significantly higher in COVID-19 patients compared with healthy controls and in both female and male patients compared with sex-matched controls. However, expression level of TNF-A was not different between COVID-19 patients and healthy controls. Expression of none of these cytokines was different between ICU-admitted patients and other patients except for IL-6 whose expression was lower in the former group compared with the latter (ratio of means = 0.33, P value = 4.82E-02). Then, we assessed diagnostic power of cytokine coding genes in differentiating between COVID-19 patients and controls. The area under curve (AUC) values ranged from 0.94 for IFN-G to 1.0 for IL-2 and IL-1B. After combining the transcript levels of all cytokines, AUC, sensitivity, and specificity values reached 100%, 100%, and 99%, respectively. For differentiation between ICU-admitted patients and other patients, IL-4 with AUC value of 0.68 had the best diagnostic power among cytokine coding genes. Expression of none of cytokine coding genes was correlated with the available clinical/demographic data including age, gender, ICU admission, or erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP) levels. This study provides further evidence for contribution of “cytokine storm” in the pathobiology of moderate/severe forms of COVID-19.

COVID-19 pandemic: Insights into genetic susceptibility to SARS-CoV-2 and host genes implications on virus spread, disease severity and outcomes

The outbreak of the newly emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) all over the world has caused global public health emergencies, international concern and economic crises. The systemic SARS-CoV-2 disease (COVID-19) can lead to death through causing unrestrained cytokines-storm and subsequent pulmonary shutdown among the elderly and patients with pre-existing comorbidities. Additionally, in comparison with poor nations without primary health care services, in developed countries with advanced healthcare system we can witness higher number of infections per one million people. In this review, we summarize the latest studies on genes associated with SARS-CoV-2 pathogenesis and propose possible mechanisms of the virus replication cycle and its triggered signaling pathways to encourage researchers to investigate genetic and immune profiles of the disease and try strategies for its treatment. Our review shows that immune response in people with different genetic background might vary as African and then Asian populations have lowest number of affected cases compared with European and American nations. Considering SARS-CoV-2 pathogenesis, we put forward some potentially important genetic gateways to COVID-19 infection including genes involved in the entry and replication of SARS-CoV-2 and the regulation of host immune response which might represent explanation for its spread, severity, and morality. Finally, we suggest that genetic alterations within these gateways could be critical factors in influencing geographical discrepancies of the virus, so it is essential to fully study them and design appropriated and reliable therapeutic agents against COVID-19.

Angiotensin-converting enzyme polymorphisms AND Alzheimer's disease susceptibility: An updated meta-analysis

Background

Many studies among different ethnic populations suggested that angiotensin converting enzyme (ACE) gene polymorphisms were associated with susceptibility to Alzheimer’s disease (AD). However, the results remained inconclusive. In the present meta-analysis, we aimed to clarify the effect of ACE polymorphisms on AD risk using all available relevant data.

Methods

Systemic literature searches were performed using PubMed, Embase, Alzgene and China National Knowledge Infrastructure (CNKI). Relevant data were abstracted according to predefined criteria.

Results

Totally, 82 independent cohorts from 65 studies were included, focusing on five candidate polymorphisms. For rs1799752 polymorphism, in overall analyses, the insertion (I) allele conferred increased risk to AD compared to the deletion (D) allele (I vs. D: OR = 1.091, 95% CI = 1.007–1.181, p = 0.032); while the I carriers showed increased AD susceptibility compared with the D homozygotes (II + ID vs. DD: OR = 1.131, 95% CI = 1.008–1.270, p = 0.036). However, none of the positive results passed FDR adjustment. In subgroup analysis restricted to late-onset individuals, the associations between rs1799752 polymorphism and AD risk were identified using allelic comparison (OR = 1.154, 95% CI = 1.028–1.295, p = 0.015, FDR = 0.020), homozygotes comparison, dominant model and recessive model (II vs. ID + DD: OR = 1.272, 95% CI = 1.120–1.444, p < 0.001, FDR < 0.001). Nevertheless, no significant association could be revealed after excluding studies not in accordance with Hardy-Weinberg equilibrium (HWE). In North Europeans, but not in East Asians, the I allele demonstrated increased AD susceptibility compared to the D allele (OR = 1.096, 95% CI = 1.021–1.178, p = 0.012, FDR = 0.039). After excluding HWE-deviated cohorts, significant associations were also revealed under homozygotes comparison, additive model (ID vs. DD: OR = 1.266, 95% CI = 1.045–1.534, p = 0.016, FDR = 0.024) and dominant model (II + ID vs. DD: OR = 1.197, 95% CI = 1.062–1.350, p = 0.003, FDR = 0.018) in North Europeans. With regard to rs1800764 polymorphism, significant associations were identified particularly in subgroup of European descent under allelic comparison (T vs. C: OR = 1.063, 95% CI = 1.008–1.120, p = 0.023, FDR = 0.046), additive model and dominant model (TT + TC vs. CC: OR = 1.116, 95% CI = 1.018–1.222, p = 0.019, FDR = 0.046). But after excluding studies not satisfying HWE, all these associations disappeared. No significant associations were detected for rs4343, rs4291 and rs4309 polymorphisms in any genetic model.

Conclusions

Our results suggested the significant but modest associations between rs1799752 polymorphism and risk to AD in North Europeans. While rs4343, rs4291 and rs4309 polymorphisms are unlikely to be major factors in AD development in our research.

The impact of ACE2 genetic polymorphisms (rs2106809 and rs2074192) on gender susceptibility to COVID-19 infection and recovery: A systematic review

Background: Epidemiological studies revealed there is a difference in susceptibility to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of differences in gender with age and males being more inflicted. There is a clear indication that deaths caused by coronavirus disease 2019 (COVID-19) in males appeared at a higher rate than females across 35 nations. The implication of associated disease-risk genes, involved in the susceptibility of COVID-19 such as the angiotensin-converting enzyme 2 (ACE2), has recently received considerable attention due to their role in severe injury of lung and mediated SARS-CoV-2 entry as a host receptor. Objectives: Herein, we aimed to systematically review how two main genetic polymorphisms of ACE2 (rs2106809 and rs2074192) can affect the gender susceptibility to SARS-CoV-2 infection. Methods: To conduct this systematic review, a literature search in PubMed, Google Scholar, ScienceDirect, and Nature was made for the period 2004 to 2020. We searched for the impact of ACE2 genetic polymorphisms (rs2106809 and rs2074192) on gender susceptibility. Results: We noticed that there was a differential genotype distribution between males and females in various global populations whereas mutant variants were common in males compared to wild-type variants among females, which may reflect differences in gender susceptibility to infection with SARS-CoV-2. Females are less susceptible to coronavirus as compare to males because of the expression of ACE2 receptor. It has a double role in favour of COVID-19 and against COVID-19. Conclusions: Male mortality is greater than female mortality, which might be attributed to the ACE2 deficiency in women. Epidemiological studies have shown that the differences in sex and age have different susceptibility to SARS-CoV-2 infection.

Egg White-Derived Peptides QVPLW and LCAY Inhibit the Activity of Angiotensin I-Converting Enzyme in Human Umbilical Vein Endothelial Cells by Suppressing Its Recruitment into Lipid Rafts

As a membrane protein, the activity of angiotensin I-converting enzyme (ACE) can be modulated via regulation of its localization in the cell membrane with food-derived peptides. This study aimed to explore the effect of egg white peptides on the cell membrane localization and activity of ACE in human umbilical vein endothelial cells. ACE activity was found to be related to lipid rafts by using methyl-β-cyclodextrin (MβCD). QVPLW and LCAY can inhibit ACE activity by preventing ACE recruitment into lipid rafts, with in situ IC₅₀ values of 238.46 ± 11.35 μM and 31.55 ± 2.64 μM in the control groups, as well as 45.43 ± 6.15 μM and 34.63 ± 1.59 μM in the MβCD groups, respectively. QVPLW and LCAY may alter the cell membrane properties, including the fluidity, potential, and permeability, and eventually promote the transposition of ACE.

The Role of Nutrition in COVID-19 Susceptibility and Severity of Disease: A Systematic Review

BACKGROUND

Many nutrients have powerful immunomodulatory actions with the potential to alter susceptibility to coronavirus disease 2019 (COVID-19) infection, progression to symptoms, likelihood of severe disease, and survival.

OBJECTIVE

The aim was to review the latest evidence on how malnutrition across all its forms (under- and overnutrition and micronutrient status) may influence both susceptibility to, and progression of, COVID-19.

METHODS

We synthesized information on 13 nutrition-related components and their potential interactions with COVID-19: overweight, obesity, and diabetes; protein-energy malnutrition; anemia; vitamins A, C, D, and E; PUFAs; iron; selenium; zinc; antioxidants; and nutritional support. For each section we provide: 1) a landscape review of pertinent material; 2) a systematic search of the literature in PubMed and EMBASE databases, including a wide range of preprint servers; and 3) a screen of 6 clinical trial registries. All original research was considered, without restriction to study design, and included if it covered: 1) severe acute respiratory syndrome coronavirus (CoV) 2 (SARS-CoV-2), Middle East respiratory syndrome CoV (MERS-CoV), or SARS-CoV viruses and 2) disease susceptibility or 3) disease progression, and 4) the nutritional component of interest. Searches took place between 16 May and 11 August 2020.

RESULTS

Across the 13 searches, 2732 articles from PubMed and EMBASE, 4164 articles from the preprint servers, and 433 trials were returned. In the final narrative synthesis, we include 22 published articles, 38 preprint articles, and 79 trials.

CONCLUSIONS

Currently there is limited evidence that high-dose supplements of micronutrients will either prevent severe disease or speed up recovery. However, results of clinical trials are eagerly awaited. Given the known impacts of all forms of malnutrition on the immune system, public health strategies to reduce micronutrient deficiencies and undernutrition remain of critical importance. Furthermore, there is strong evidence that prevention of obesity and type 2 diabetes will reduce the risk of serious COVID-19 outcomes. This review is registered at PROSPERO as CRD42020186194.

An Organometallic Strategy for Cysteine Borylation

Synthetic bioconjugation at cysteine (Cys) residues in peptides and proteins has emerged as a powerful tool in chemistry. Soft nucleophilicity of the sulfur in Cys renders an exquisite chemoselectivity with which various functional groups can be placed onto this residue under benign conditions. While a variety of reactions have been successful at producing Cys-based bioconjugates, the majority of these feature sulfur-carbon bonds. We report Cys-borylation, wherein a benchtop stable Pt(II)-based organometallic reagent can be used to transfer a boron-rich cluster onto a sulfur moiety in unprotected peptides forging a boron-sulfur bond. Cys-borylation proceeds at room temperature and tolerates a variety of functional groups present in complex polypeptides. Further, the bioconjugation strategy can be applied to a model protein modification of Cys-containing DARPin (designed ankyrin repeat protein). The resultant bioconjugates show no additional toxicity compared to their Cys alkyl-based congeners. Finally, we demonstrate how the developed Cys-borylation can enhance the proteolytic stability of the resultant peptide bioconjugates while maintaining the binding affinity to a protein target.

Genetic and epigenetic factors associated with increased severity of Covid-19

Since December 2019, a new form of severe acute respiratory syndrome (SARS) from a novel strain of coronavirus (SARS coronavirus 2 [SARS-CoV-2]) has been spreading worldwide. The disease caused by SARS-CoV-2 was named Covid-19 and declared as a pandemic by the World Health Organization in March 2020. Clinical symptoms of Covid-19 range from common cold to more severe disease defined as pneumonia, hypoxia, and severe respiratory distress. In the next stage, disease can become more critical with respiratory failure, sepsis, septic shock, and/or multiorgan failure. Outcomes of Covid-19 indicate large gaps between the male-female and the young-elder groups. Several theories have been proposed to explain variations, such as gender, age, comorbidity, and genetic factors. It is likely that mixture of genetic and nongenetic factors interplays between virus and host genetics and determines the severity of disease outcome. In this review, we aimed to summarize current literature in terms of potential host genetic and epigenetic factors that associated with increased severity of Covid-19. Several studies indicated that the genetic variants of the SARS-CoV-2 entry mechanism-related (angiotensin-converting enzymes, transmembrane serine protease-2, furin) and host innate immune response-related genes (interferons [IFNs], interleukins, toll-like receptors), and human leukocyte antigen, ABO, 3p21.31, and 9q34.2 loci are critical host determinants related to Covid-19 severity. Epigenetic mechanisms also affect Covid-19 outcomes by regulating IFN signaling, angiotensin-converting enzyme-2, and immunity-related genes that particularly escape from X chromosome inactivation. Enhanced understanding of host genetic and epigenetic factors and viral interactions of SARS-CoV-2 is critical for improved prognostic tools and innovative therapeutics.

Angiotensin System Polymorphisms' in SARS-CoV-2 Positive Patients: Assessment Between Symptomatic and Asymptomatic Patients: A Pilot Study

Introduction

The renin-angiotensin-aldosterone system (RAAS), a metabolic cascade regulating pressure and circulating blood volume, has been considered the main system involved in the pathogenesis of severe lung injury and organs decline in COVID-19 patients. The angiotensin I-converting enzyme (ACE1), angiotensin-converting enzyme 2 (ACE2), angiotensinogen (AGT) and receptors angiotensin II receptor type 1 (AGTR1) are key factors for SARS-CoV-2 entering in the cells, sodium and water retention with an increase blood pressure, promotion of fibrotic and inflammatory phenomena resulting in a cytokine storm.

Methods

In this pilot study, the frequencies of six polymorphisms in the ACE1, ACE2, AGT and AGTR1 genes were analysed in symptomatic patients affected by COVID-19 and compared with the results obtained from asymptomatic subjects.

Results

Thus, we have identified that rs2074192 (ACE2), rs1799752 (ACE1) and rs699 (AGT) SNPs could potentially be a valuable tool for predicting the clinical outcome of SARS-CoV-2 infected patients. A genetic predisposition may be prospected for severe internal organ damages and poor prognosis in patients with COVID-19 disease, as observed in symptomatic vs asymptomatic.

Conclusion

This study provides evidence that analysis of RAAS polymorphisms could be considered the key point in understanding and predicting the SARS-CoV-2 course infection.

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.

Clinical and demographic characteristics of patients with COVID-19 infection: Statistics from a single hospital in Iran

Coronavirus disease 2019 (COVID-19) has caused a global pandemic in early 2020. This infectious disorder has a heterogeneous course ranging from asymptomatic disorder to a critical situation needing intensive cares. In the current study, we present a report of affected patients admitted in a single hospital in Iran. Eighty-two hospitalized patients with COVID-19 were assessed. Demographic, clinical, and paraclinical parameters were gathered and statistically analyzed. The median age (IQR) of the patients was 57.32 (45.75, 70) years. At primary evaluation, fever was present in 45.12% of the affected individuals. The most common clinical symptoms were dyspnea (81.71%) and cough (65.85%). Totally, 12 (14.63%) and 14 (17.07%) of patients had low and high WBC counts, respectively. Lymphopenia was detected in 36 (43.9%) of patients, while 6 (7.32%) of patients had lymphocytosis. High levels of Il-6 were detected in 4 (4.88%) of patients. CRP levels were elevated in 69 (84.1%) of patients. The median (IQR) of hospitalization was 7 (5, 9) days. Totally, 26 patients (31%) were hospitalized in ICU. All patients were discharged with good health conditions except for one patient who died. The current study shows the heterogeneous clinical manifestations and paraclinical parameters of COVID-19 patients.

A study of differential circRNA and lncRNA expressions in COVID-19-infected peripheral blood

To conquer the worldwide outbreak of COVID-19 virus, a large number of studies have been carried out on COVID-19 infection, transmission and treatment. However, few studies have been conducted from the perspectives of circRNA and lncRNA, which are known to be involved in regulating many life activities, such as immune tolerance and immune escapes, and hence may provide invaluable information in the emerging COVID-19 infection and recurrence. Moreover, exosomes has been reported to play an important role in COVID-19 recurrence, and thus may interact with the expression of circRNA and lncRNA. In this work, we sequenced circRNA, lncRNA and mRNA from recurrent COVID-19 patients and healthy people, and compared the differences. GO and KEGG enrichment analysis show that differentially expressed circRNA and lncRNA are mainly involved in the regulation of host cell cycle, apoptosis, immune inflammation, signaling pathway and other processes. The comparison to exosomes related databases shows that there are 114 differentially expressed circRNA, and 10 differentially expressed lncRNA related to exosomes. These studies provide reference for exploring circRNA and lncRNA to study the infection mechanism of COVID-19, their diagnostic and therapeutic values, as well as the possibility to employ them as biomarkers.

Endothelial cells and SARS-CoV-2: An intimate relationship

Angiotensin-converting enzyme 2 (ACE2) is an important player of the renin-angiotensin-aldosterone system (RAAS) in regulating the conversion of angiotensin II into angiotensin (1-7). While expressed on the surface of human cells, such as lung, heart, kidney, neurons, and endothelial cells (EC), ACE2 is the entry receptor for SARS-CoV-2. Here, we would like to highlight that ACE2 is predominant on the EC membrane. Many of coronavirus disease 2019 (COVID-19) symptoms have been associated with the large recruitment of immune cells, directly affecting EC. Additionally, cytokines, hypoxia, and complement activation can trigger the activation of EC leading to the coagulation cascade. The EC dysfunction plus the inflammation due to SARS-CoV-2 infection may lead to abnormal coagulation, actively participating in thrombo-inflammatory processes resulting in vasculopathy and indicating poor prognosis in patients with COVID-19. Considering the intrinsic relationship between EC and the pathophysiology of SARS-CoV-2, EC-associated therapies such as anticoagulants, fibrinolytic drugs, immunomodulators, and molecular therapies have been proposed. In this review, we will discuss the role of EC in the lung inflammation and edema, in the disseminate coagulation process, ACE2 positive cancer patients, and current and future EC-associated therapies to treat COVID-19.

Stroke in SARS-CoV-2 Infection: A Pictorial Overview of the Pathoetiology

Since the early days of the pandemic, there have been several reports of cerebrovascular complications during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Numerous studies proposed a role for SARS-CoV-2 in igniting stroke. In this review, we focused on the pathoetiology of stroke among the infected patients. We pictured the results of the SARS-CoV-2 invasion to the central nervous system (CNS) via neuronal and hematogenous routes, in addition to viral infection in peripheral tissues with extensive crosstalk with the CNS. SARS-CoV-2 infection results in pro-inflammatory cytokine and chemokine release and activation of the immune system, COVID-19-associated coagulopathy, endotheliitis and vasculitis, hypoxia, imbalance in the renin-angiotensin system, and cardiovascular complications that all may lead to the incidence of stroke. Critically ill patients, those with pre-existing comorbidities and patients taking certain medications, such as drugs with elevated risk for arrhythmia or thrombophilia, are more susceptible to a stroke after SARS-CoV-2 infection. By providing a pictorial narrative review, we illustrated these associations in detail to broaden the scope of our understanding of stroke in SARS-CoV-2-infected patients. We also discussed the role of antiplatelets and anticoagulants for stroke prevention and the need for a personalized approach among patients with SARS-CoV-2 infection.

Application of Machine Learning in Diagnosis of COVID-19 Through X-Ray and CT Images: A Scoping Review

Coronavirus disease, first detected in late 2019 (COVID-19), has spread fast throughout the world, leading to high mortality. This condition can be diagnosed using RT-PCR technique on nasopharyngeal and throat swabs with sensitivity values ranging from 30 to 70%. However, chest CT scans and X-ray images have been reported to have sensitivity values of 98 and 69%, respectively. The application of machine learning methods on CT and X-ray images has facilitated the accurate diagnosis of COVID-19. In this study, we reviewed studies which used machine and deep learning methods on chest X-ray images and CT scans for COVID-19 diagnosis and compared their performance. The accuracy of these methods ranged from 76% to more than 99%, indicating the applicability of machine and deep learning methods in the clinical diagnosis of COVID-19.

Angiotensin-converting enzyme 2: from a vasoactive peptide to the gatekeeper of a global pandemic

PURPOSE OF REVIEW

We provide a comprehensive overview of angiotensin-converting enzyme 2 (ACE2) as a possible candidate for pharmacological approaches to halt inflammatory processes in different pathogenic conditions.

RECENT FINDINGS

ACE2 has quickly gained prominence in basic research as it has been identified as the main entry receptor for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). This novel pathogen causes Coronavirus Disease 2019 (COVID-19), a pathogenic condition that reached pandemic proportion and is associated with unprecedented morbidity and mortality.

SUMMARY

The renin-angiotensin system is a complex, coordinated hormonal cascade that plays a pivotal role in controlling individual cell behaviour and multiple organ functions. ACE2 acts as an endogenous counter-regulator to the pro-inflammatory and pro-fibrotic pathways triggered by ACE through the conversion of Ang II into the vasodilatory peptide Ang 1-7. We discuss the structure, function and expression of ACE2 in different tissues. We also briefly describe the role of ACE2 as a pivotal driver across a wide spectrum of pathogenic conditions, such as cardiac and renal diseases. Furthermore, we provide the most recent data concerning the possible role of ACE2 in mediating SARS-CoV-2 infection and dictating COVID-19 severity.

Three salvianolic acids inhibit 2019-nCoV spike pseudovirus viropexis by binding to both its RBD and receptor ACE2

Since December 2019, the new coronavirus (also known as severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2, 2019-nCoV])-induced disease, COVID-19, has spread rapidly worldwide. Studies have reported that the traditional Chinese medicine Salvia miltiorrhiza possesses remarkable antiviral properties; however, the anti-coronaviral activity of its main components, salvianolic acid A (SAA), salvianolic acid B (SAB), and salvianolic acid C (SAC) is still debated. In this study, we used Cell Counting Kit-8 staining and flow cytometry to evaluate the toxicity of SAA, SAB, and SAC on ACE2 (angiotensin-converting enzyme 2) high-expressing HEK293T cells (ACE2^h cells). We found that SAA, SAB, and SAC had a minor effect on the viability of ACE2^h cells at concentrations below 100 μM. We further evaluated the binding capacity of SAA, SAB, and SAC to ACE2 and the spike protein of 2019-nCoV using molecular docking and surface plasmon resonance. They could bind to the receptor-binding domain (RBD) of the 2019-nCoV with a binding constant (K_D ) of (3.82 ± 0.43) e-6 M, (5.15 ± 0.64)e-7 M, and (2.19 ± 0.14)e-6 M; and bind to ACE2 with K_D (4.08 ± 0.61)e-7 M, (2.95 ± 0.78)e-7 M, and (7.32 ± 0.42)e-7 M, respectively. As a result, SAA, SAB, and SAC were determined to inhibit the entry of 2019-nCoV Spike pseudovirus with an EC₅₀ of 11.31, 6.22, and 10.14 μM on ACE2^h cells, respectively. In conclusion, our study revealed that three Salvianolic acids can inhibit the entry of 2019-nCoV spike pseudovirus into ACE2^h cells by binding to the RBD of the 2019-nCoV spike protein and ACE2 protein.

Distribution of the ACE1 D Allele in the Bosnian-Herzegovinian Population and its Possible Role in the Regional Epidemiological Picture of COVID-19

Background: The human angiotensin I converting enzyme 1 (ACE1) gene insertion/deletion (I/D) polymorphism is classified based on the presence or absence of a 287 bp Alu sequence. The ACE1 D allele is associated with higher ACE1 concentrations in tissues. Previous research has shown that susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is primarily determined by the affinity between the viral receptor-binding domain and the host human receptor angiotensin-converting enzyme 2 (hACE2) receptor. In the human genome, ACE2 is identified as a homolog to ACE1. Objective: The purpose of this study was to characterize the ACE1 D allele distribution in Bosnia and Herzegovina (B&H), so as to compare it to population data from other European countries and to investigate the potential correlation between D allele frequencies and coronavirus disease 2019 (COVID-19) epidemiological findings in selected European populations. Methods: The ACE1 D allele frequencies in 18 selected European populations were analyzed and compared with COVID-19 prevalence, mortality, and severity using multivariate linear regression analysis. Results and Discussion: The ACE1 D allele distribution within the B&H population was similar to its distribution in other European populations. Regression analysis showed no significant correlation between the D allele frequency and the incidence of infections between the examined populations, nor with the rates of fatality and severe cases. Conclusion: There is no clear statistical evidence that the ACE1 D allele is associated with increased or decreased COVID-19 incidence, mortality, and case severity within the investigated populations.

Animal Welfare and Livestock Supply Chain Sustainability Under the COVID-19 Outbreak: An Overview

The COVID-19 pandemic, caused by the emergence of a new strain of coronavirus (SARS-CoV-2) around the end of December 2019, has caused a worldwide public health emergency and a socioeconomic crisis during 2020. The lockdown imposed to cope with the health issues caused by the outbreak of the disease has dramatically challenged and negatively affected all the economic sectors of the modern global economy. Specifically, the livestock sector and its related industries are among the most impacted sectors. This is mainly ascribed to the limitations of animal movement and the decrease of production inputs' availability. Other factors negatively affecting the sustainability of the livestock sector have been the shortage of workers due to the lockdown/curfew, the strong decrease in the purchasing power of the consumer, and the intensification of health care tasks. Such an impact is not only highly relevant because of their economic consequences, but also because of the effects of the lockdown and sanitary rules on animal care and welfare. The current review aims to offer: (a) a comprehensive overview of the impact of COVID-19 on the welfare of farm animals and on the performance of livestock farming systems, on food chain sustainability, and finally, on the global economy and food security; and (b) a prospective outline of alleviation actions.

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.

COVID's Razor: RAS Imbalance, the Common Denominator Across Disparate, Unexpected Aspects of COVID-19

A modern iteration of Occam's Razor posits that "the simplest explanation is usually correct." Coronavirus Disease 2019 involves widespread organ damage and uneven mortality demographics, deemed unexpected from what was originally thought to be "a straightforward respiratory virus." The simplest explanation is that both the expected and unexpected aspects of COVID-19 share a common mechanism. Silent hypoxia, atypical acute respiratory distress syndrome (ARDS), stroke, olfactory loss, myocarditis, and increased mortality rates in the elderly, in men, in African-Americans, and in patients with obesity, diabetes, and cancer-all bear the fingerprints of the renin-angiotensin system (RAS) imbalance, suggesting that RAS is the common culprit. This article examines what RAS is and how it works, then from that baseline, the article presents the evidence suggesting RAS involvement in the disparate manifestations of COVID-19. Understanding the deeper workings of RAS helps one make sense of severe COVID-19. In addition, recognizing the role of RAS imbalance suggests potential routes to mitigate COVID-19 severity.

Safety procedures for exercise testing in the scenario of COVID-19: a position statement of the Società Italiana Scienze Motorie e Sportive

Recent data on coronavirus disease 2019 (COVID-19) pandemic showed that the virus is mostly conveyed by respiratory droplets that are produced at high intensity especially when an infected subject coughs or sneezes. Therefore, elevated volume ventilations, usually reached during physical efforts and exercise, are a potential source of contamination. On the other hand, the lockdown period which has lasted for nearly 2 months and is actually involving several countries worldwide, obliged a large part of human population to sedentary behaviors, drastically reducing their physical activity level, and reducing their cardiopulmonary fitness. Therefore, cardiopulmonary exercise testing could be beneficial, so that a safe and well-weighted return to pre-lockdown active lifestyle can be efficiently planned. However, specific guidelines on exercise testing safety procedures in the era of COVID-19 are unavailable so far. This article is aimed to provide an overview of safety procedures for exercise testing during and after COVID-19 worldwide pandemic.

Altered cytokine levels and immune responses in patients with SARS-CoV-2 infection and related conditions

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic in early 2020. The infection has been associated with a wide range of clinical symptoms. In the severely affected patients, it has caused dysregulation of immune responses including over-secretion of inflammatory cytokines and imbalances in the proportion of naïve helper T cells, memory helper T cells and regulatory T cells. Identification of the underlying mechanism of such aberrant function of immune system would help in the prediction of disease course and selection of susceptible patients for more intensive cares. In the current review, we summarize the results of studies which reported alterations in cytokine levels and immune cell functions in patients affected with SARS-CoV-2 and related viruses.

Effects of host genetic variations on response to, susceptibility and severity of respiratory infections

The recent outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created a global crisis, necessitating the identification of genetic factors that modulate the risk of disorder or its severity. The current data about the role of genetic risk factors in determination of rate of SARS-CoV-2 infection in each ethnic group and the severity of disorder is limited. Moreover, several confounding parameters such as the number of tests performed in each country, the structure of the population especially the age distribution, the presence of risk factors for respiratory disorders such as smoking and other environmental factors might be involved in the variability in disease course or prevalence of infection among different ethnic groups. However, assessment of the role of genetic variants in determination of the course of other respiratory infections might help in recognition of possible candidate for further analysis in patients affected with SARS-CoV-2. In the current review, we summarize the data showing the association between genomic variants and risk of acute respiratory distress syndrome, respiratory infections or severity of these conditions with an especial focus on the SARS-CoV-2.

Novel coronavirus infection and Kawasaki disease

There is a global problem of increment of the number of children with clinical features that mimic Kawasaki Disease (KD) during the ongoing Coronavirus Disease 2019 (COVID-19) pandemic. The disease was first reported by Tomisaku Kawasaki, a Japanese pediatrician, in a four-year-old child with a rash and fever at the Red Cross Hospital in Tokyo in January 1961. Now Kawasaki disease is recognized worldwide. The complexity of symptoms was defined as an «acute febrile mucocutaneous lymphnode syndrome". At the moment, it is still unclear whether the coronavirus itself can lead to development of mucocutaneous lymph node syndrome. However, it is believed that COVID-19 virus infection worsens the course of Kawasaki disease, and in some cases, children affected by SARS-V-2 may develop a disease that has a clinical picture similar to Kawasaki disease.