key: cord-0939692-njmcrrgk authors: Pati, Abhijit; Mahto, Harishankar; Padhi, Sunali; Panda, Aditya K title: ACE deletion allele is associated with susceptibility to SARS-CoV-2 infection and mortality rate: An epidemiological study in the Asian population date: 2020-08-10 journal: Clin Chim Acta DOI: 10.1016/j.cca.2020.08.008 sha: c743cfba1351e366a5d45334484bd977eed84ae0 doc_id: 939692 cord_uid: njmcrrgk BACKGROUND: Severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) is believed to have emerged from Wuhan, China, and spreads over 215 countries worldwide. The spike protein of SARS-CoV-2 binds to angiotensin-converting enzyme-2 (ACE-2) receptors and enter the host cells. Several reports have been highlighted the importance of ACE-2 on the pathogenesis of COVID-19. In the present study, we hypothesize that a functional insertion/deletion polymorphism in the ACE gene could be associated with SARS-CoV-2 infection and mortality. MATERIALS AND METHODS: PubMed and Google scholar search engines were used to obtained data on the prevalence of ACE I/D polymorphism in different countries of the Asia continent. Data on COVID-19 infection rate (per million), mortality/million, and percentage of recovery were acquired form worldometer website. The Spearman rank correlation test performed to investigate the correlation of allele ‘D’ with SARS-CoV-2 infection, mortality rate, and recovery percentage. RESULTS: Epidemiological investigation revealed a significant positive correlation of D allele of ACE polymorphism with SARS-CoV-2 infection (r=0.502,p=0.008, n=26) and mortality rate (r=0.620,p=0.002, n=22) in Asian population. However, no significant role of ACE I/D polymorphism was observed with recovery rate of patients from SARS-CoV-2 infection (r=-0.208,p=0.352, n=22). CONCLUSIONS: Allele D of ACE insertion/deletion polymorphism is associated with the rate of infection and mortality in the Asian population. The coronavirus disease 2019 , also known as severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) has emerged from Wuhan, China, in December 2019 [1] and spread rapidly across worldwide. On 11 th March 2020, the World Health Organization (WHO) declared COVID-19 as a pandemic (https://www.who.int/dg/speeches/detail/whodirector-general-s-opening-remarks-at-the-media-briefing-on-covid-19---11-march-2020). Till date (27 th July 2020), 17.17 million of subjects were infected with SARS-CoV-2 in 215 countries, and about 0.66 million of death has been reported throughout the globe (https://www.worldometers.info/coronavirus/#countries). The recovery rate of SARS-CoV-2 infected subjects remained at 62.23% (https://www.worldometers.info/coronavirus/#countries). The spike protein of SARS-CoV-2 efficiently binds to the angiotensin-converting enzyme 2 (ACE2) receptors and facilitate the invading of the virus into the host cell [2] . ACE2 receptor is a type I transmembrane glycoprotein consisting of 805 amino acid length [3] . ACE2 receptors also mediate the cellular entry of SARS-CoV and NL63 [4] . SARS-CoV shares about 76% similarity in amino acid sequence with SARS-CoV-2 [5] . Various reports in the mouse model have deciphered importance of ACE2 in susceptibility and pathogenesis of SARS-CoV infections: the virus entry rate is enhanced with overexpression of ACE-2 receptors [6] , antibodies to ACE-2 receptors significantly blocks entry of SARS-CoV [4] and ACE2 knockout mice had lower pulmonary lesion compared to the wildtype [7] . These observations collectively indicate an essential role ACE2 receptor in the pathogenesis of SARS-CoV-2. Angiotensin-converting enzyme (ACE) share about 40% of sequence homology with ACE-2 [8] , and several lines of evidence have demonstrated a counter-regulatory relationship between these two molecules [9] . The administration of ACE inhibitors significantly increased the expression levels of ACE-2 [10] . As levels of ACE and ACE2 are interwoven, and ACE2 plays a vital role in SARS-CoV-2 infection and pathogenesis, we hypothesized that differential levels of ACE could be associated with SARS-CoV-2 infections and mortality rate. ACE gene is located at the long arm (q23.3) of the 17 th chromosome and consists of 26 exons and 25 introns [11] . A functional insertion-deletion (I/D) polymorphism of 286bp has been reported in the intron 16 of the ACE gene [11] . The deletion (D) and insertion allele (I) are associated with an elevated and diminished ACE level and enzyme activity, respectively [12, 13] . Previous reports demonstrated the association of ACE D allele with the incidence of pneumonia in SARS patients [14] and the death of subjects with acute respiratory distress syndrome [15] . These observations tempted us to investigate the importance of ACE I/D polymorphism in susceptibility to SARS-CoV-2 infection and related mortality. In the present epidemiological investigation, we tested the possible association between ACE I/D polymorphism with SARS-CoV-2 infection, mortality rate, and percentage of recovery in the Asian population. For COVID-19 related information in the Asian continent, we explored the worldometer site (https://www.worldometers.info/coronavirus/) and various data such as country name, number cases per million, number of death per million, number of patients recovered from SARS-CoV-2 infections were obtained (assessed on 27 th July 2020). The recovery rate in the percentage of SARS-CoV-2 patients was calculated by using the total number of infected cases and the number of patients who recovered after treatment. Total expenditure on health as percentage of gross domestic product (GDP) of various countries (www.who.int/countries/en/), doctors, and nurse density per 10,000 individuals (https://www.who.int/data/gho/data/indicators/indicator-details/GHO/medical-doctors-(per-10-000-population) were acquired from the World Health Organisation database. Literature search database PubMed and google scholar were screened for the prevalence of ACE I/D polymorphism in different countries of Asia where SARS-CoV-2 infection has been reported. All publications were inspected, and authors' details, country name, ACE I/D genotypes number or frequency, allele number, or frequency were extracted. For countries with more than one report, genotype or allele data were pooled, and allele frequency was calculated. The genotypes distributions of ACE I/D polymorphism in all reports were screened for Hardy-Weinberg equilibrium (HWE), and the studies deviated from the HWE were excluded from the present investigation. As the health care facility depends upon the economic condition of the country, for mortality analysis, countries with expenditure on health sector lower than 3% of their GDP were not included. The prevalence of ACE I/D genotypes and alleles frequency was calculated by manual counting. All statistical analysis was performed by Graphpad Prism 8. publications were considered for the current investigation (Table-1 (Figure-1C ). ACE2 receptor plays a crucial role in cellular invading of SARS-CoV-2 as well as various pathophysiological conditions of the COVID-19 [16] . The spike protein of the SARS-CoV-2 binds to ACE2 receptors and facilitates the internalization of the virus [2] . The dominant allele 'D' of ACE I/D polymorphism has been associated with elevated levels of ACE [12, 13] . In the present study, we observed a significant positive correlation between the frequency of D allele and the number of SARS-CoV-2 infected cases/million in the Asian populations. The mechanism of how major allele (D) of ACE I/D polymorphism is associated with a higher infection rate of SARS-CoV-2 is not known. Since the levels of ACE and ACE2 are a counter complement to each other [17] , lower levels of ACE2 could be expected in subject those harboring the major allele D of ACE I/D polymorphism. Furthermore, the soluble form of ACE2 protein which is believed to counteract SARS-CoV-2 [18] is scarcely present in the circulation than the membrane-bound ACE2 receptor [16] ; thus the probability of interaction between SARS-CoV-2 and ACE2 receptor is higher, and that may facilitate the invasion of the host cell up to a greater extent. We observed a significant positive correlation between allele D and mortality rate in the Asian populations indicating higher levels of ACE are deleterious in SARS-CoV-2 infected subjects. Mortality related to SARS-CoV-2 infections has been linked to various comorbid conditions such as hypertension, diabetes, hyperlipidemia, coronary artery disease, and renal disease [19] . High producer of ACE, the DD genotype has been associated with susceptibility to hypertension [20] , type 2 diabetes [21] , coronary artery disease [22] and hyperlipidemia [22] indicating a possible role of ACE I/D polymorphism with SARS-CoV-2 related mortality. An earlier study in thirty-three countries, including 25 European, three north-African, and five from middle East continents, highlighted a negative correlation between deletion allele frequency of ACE I/D polymorphism with SARS-CoV-2 infection and mortality rate [23] . However, in the present report, we observed a positive correlation of allele D with infection an mortality rate of COVID-19. The possible reasons for the discrepancy would be the differential r=0.620, p=0.002, n=22) and patients recovery rate (C: r=-0.208, p=0.352, n=22) . 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Authors declare no conflict of interest.