Serum ACE2 Research Articles

#2395 Elevated circulating ACE2 activity is related with a major COVID-19 severity

Abstract Background and Aims The angiotensin 2 converser enzyme (ACE2) is the cell entry receptor for SARS-CoV-2. SARS-CoV2 participates in ACE2 shedding from cell membrane, increasing soluble ACE2. The present study aims to evaluate if ACE2 serum levels are to COVID-19 prognosis. Method During the first wave of COVID-19 pandemic and during March and April 2020, 2118 first emergency attendance serum samples from diagnosed COVID-19 patients from Barcelona Vall d'Hebron Hospital were obtained. Age, sex, previous comorbidities, clinical and analytical variables were collected from the patient clinical records. Patients that were admitted to ICU, required mechanical ventilation or died due to COVID-19 were considered severe patients. Serum ACE2 activity was measured by enzymatic activity assay. Results Patients with severe COVID-19 were older and with a major number of comorbidities (Table 1). Circulating ACE2 activity at admission was increased in 0.34 relative fluorescence units (RFUs)/ng/μL (CI 95%: 0.24-0.43, p < 0.001) in patients that developed severe COVID-19. A logistic regression model adjusted by age, sex, diabetes, hypertension, obesity, cardiovascular disease, chronic kidney disease and renin angiotensin blockers, showed that high circulating ACE2 activity was still related to a worse prognosis (OR: 2.0, 95% CI: 1.7–2.4, p < 0.001). High serum ACE2 activity ≥0.56 RFU/ng/μL provided the best sensitivity (62%) and specificity (61%) relation, whereas values ≥1.3 RFU/ng/μL were significantly related to a worse prognosis of the disease with a 95% specificity. Conclusion High levels of circulating ACE2 activity when patients with COVID-19 are admitted to the Emergency Department are independently related with a subsequent severe disease. Additionally, although most of the comorbidities analyzed are significantly increased in severe COVID-19 patients as compared to mild COVID-19 patients, the results of the logistic regression model point out that they seem not to be a risk factor in the overall model, except for obesity, age and sex.

AI-Driven Spectral Decomposition: Predicting the Most Probable Protein Compositions from Surface Enhanced Raman Spectroscopy Spectra of Amino Acids.

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for elucidating the molecular makeup of materials. It possesses the unique characteristics of single-molecule sensitivity and extremely high specificity. However, the true potential of SERS, particularly in capturing the biochemical content of particles, remains underexplored. In this study, we harnessed transformer neural networks to interpret SERS spectra, aiming to discern the amino acid profiles within proteins. By training the network on the SERS profiles of 20 amino acids of human proteins, we explore the feasibility of predicting the predominant proteins within the µL-scale detection volume of SERS. Our results highlight a consistent alignment between the model's predictions and the protein's known amino acid compositions, deepening our understanding of the inherent information contained within SERS spectra. For instance, the model achieved low root mean square error (RMSE) scores and minimal deviation in the prediction of amino acid compositions for proteins such as Bovine Serum Albumin (BSA), ACE2 protein, and CD63 antigen. This novel methodology offers a robust avenue not only for protein analytics but also sets a precedent for the broader realm of spectral analyses across diverse material categories. It represents a solid step forward to establishing SERS-based proteomics.

Abstract P130: Higher Circulating Angiotensin Converting Enzyme 2 (ACE2) and ACE2 to ACE Ratio Are Associated With Lower COVID-19 Mortality: A Mechanistic Substudy of the ACTIV-4 Host Tissue Trials

Background: SARS-Cov-2 targets the peptidase ACE2, a key component of the renin-angiotensin system (RAS), which directly regulates the balance of the vasoconstrictor/inflammatory peptide Ang II and the vasodilator/anti-inflammatory peptide Ang-(1-7). Few studies have quantified the circulating elements of the RAS longitudinally in SARS-Cov-2 infection and their association with COVID-19 outcomes. Objective: Evaluate the association of circulating RAS enzymes with mortality in critically ill patients with COVID-19. Methods: We quantified serum ACE and ACE2 concentrations by ELISA among 111 patients hospitalized for confirmed SARS-Cov-2 infection with new onset hypoxemia who were randomized to the placebo arm of the ACTIV-4 Host Tissue trials investigating RAS pathway interventions. Serum was collected at baseline/randomization (Day 0) and 1, 3, and 5 days after randomization. We used multivariable Cox regression to estimate the association of baseline and longitudinal ACE and ACE2 with 90-day mortality. Hazard ratios (HR) for RAS enzyme concentrations were adjusted for age, sex, race/ethnicity, baseline level of O 2 support, obesity, hypertension, RAS inhibitor use prior to admission, and vasopressor use within 7 days of admission. Results: Participants were aged 18-90 (mean [SD] = 55 [14]) years, 62% male, 42% non-White, with 58% and 48% prevalence of obesity and hypertension, respectively. There were 22 (20%) deaths over 90 days of follow-up (median [25%, 75%] time to event = 16 [9, 29] days). Relative to participants with values below the sample median, those with higher Day 0 ACE2 (>4.9 pM; adjusted HR [95% CI] = 0.07 [0.02, 0.33]) and ACE2/ACE ratio (>6.0*10 -3 ; adjusted HR = 0.08 [0.01, 0.39]) had significantly lower mortality. Similarly, when analyzed as continuous, log 2 -normalized, time-varying predictors from Day 0 to Day 5, two-fold increments in ACE2 (adjusted HR = 0.81 [0.69, 0.96]) and ACE2/ACE ratio (adjusted HR = 0.78 [0.64, 0.96]) over this period were associated with lower mortality. Results did not differ by hypertension status (interaction p=0.385 and 0.278 for Day 0 ACE2 and ACE2/ACE ratio, respectively, and p=0.714 and 0.457 for time-varying ACE2 and ACE2/ACE ratio, respectively). In contrast, neither ACE levels at Day 0 (>1.3 nM; adjusted HR = 1.23 [0.41, 3.67]) nor time-varying ACE (adjusted HR = 1.21 [0.75, 1.95]) were associated with mortality. Conclusions: Higher baseline and longitudinal serum ACE2 levels, but not ACE, were associated with markedly reduced mortality among hospitalized patients with COVID-19, consistent with a protective role for ACE2. Whether serum ACE2 levels arise from tissue ACE2 shedding, thus binding less virus to tissue, should be explored further. A better understanding of the RAS timecourse in severe COVID-19 illness could identify patients at greater risk for adverse outcomes and inform targeted treatment strategies.

Serum ACE2 and S19P gene polymorphism in Egyptian patients with COVID-19 infection: correlation with disease severity

The expression of ACE2 is linked to disease severity in COVID-19 patients. The ACE2 receptor gene polymorphisms are considered determinants for SARS-CoV-2 infection and its outcome. In our study, serum ACE2 and its genetic variant S19P rs73635825 polymorphism were investigated in 114 SARS-CoV-2 patients. The results were compared with 120 control subjects. ELISA technique and allele discrimination assay were used for measuring serum ACE2 and genotype analysis of ACE2 rs73635825. Our results revealed that serum ACE2 was significantly lower in SARS-CoV-2 patients (p = 0.0001), particularly in cases with hypertension or diabetes mellitus. There was a significant difference in the genotype distributions of ACE2 rs73635825 A > G between COVID-19 patients and controls (p-value = 0.001). A higher frequency of the heterozygous AG genotype (65.8%) was reported in COVID-19 patients. The G allele was significantly more common in COVID-19 patients (p < 0.0001). The AG and GG genotypes were associated with COVID-19 severity as they were correlated with abnormal laboratory findings, GGO, CXR, and total severity scores with p < 0.05. Our results revealed that the ACE2 S19P gene variant is correlated with the incidence of infection and its severity, suggesting the usefulness of this work in identifying the susceptible population groups for better disease control.

Impact of ACE I gene insertion/deletion, A-240T polymorphisms and the renin–angiotensin–aldosterone system on COVID-19 disease

BackgroundThe coronavirus disease 2019 (COVID-19) pandemic is driven by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which has led to an enormous burden on patient morbidity and mortality. The renin–angiotensin–aldosterone system (RAAS) plays a significant role in various pulmonary diseases. Since SARS-CoV-2 utilizes the angiotensin-converting enzyme (ACE)2 receptor to exert its virulence and pathogenicity, the RAAS is of particular importance in COVID 19.MethodsOur preliminary study investigates retrospectively the influence of selected ACE-polymorphisms (I/D location at intron 16 in the B-coding sequence (rs4646994) and A-240T (rs 4291) at the A-promoter) as well as ACE1 and ACE2 serum levels on disease severity and the inflammatory response in inpatients and outpatients with COVID-19.ResultsOur study included 96 outpatients and 88 inpatients (65.9% male, mean age 60 years) with COVID-19 from April to December 2020 in four locations in Germany. Of the hospitalized patients, 88.6% participants were moderately ill (n = 78, 64% male, median age 60 years), and 11.4% participants were severely ill or deceased (n = 10, 90% male, median age 71 years). We found no polymorphism-related difference in disease, in age distribution, time to hospitalization and time of hospitalization for the inpatient group. ACE1 serum levels were significantly increased in the DD compared to the II polymorphism and in the TT compared to the AA polymorphism. There was no significant difference in ACE 1 serum levels l between moderately ill and severely ill patients. However, participants requiring oxygen supplementation had significantly elevated ACE1 levels compared to participants not requiring oxygen, with no difference in ACE2 levels whereas females had significantly higher ACE2 levels.ConclusionsAlthough there were no differences in the distribution of ACE polymorphisms in disease severity, we found increased proinflammatory regulation of the RAAS in patients with oxygen demand and increased serum ACE2 levels in women, indicating a possible enhanced anti-inflammatory immune response.Clinical trial registration: PreBiSeCov: German Clinical Trials Register, DRKS-ID: DRKS00021591, Registered on 27th April 2020.

The Serum ACE2, CTSL, AngII, and TNFα Levels after COVID-19 and mRNA Vaccines: The Molecular Basis.

The SARS-CoV-2 virus as well as the COVID-19 mRNA vaccines cause an increased production of proinflammatory cytokines. We investigated the relationship between ACE2, CTSL, AngII, TNFα and the serum levels of IL-6, IL-10, IL-33, IL-28A, CD40L, total IgM, IgG, IgA and absolute count of T- and B-lymphocytes in COVID-19 patients, vaccinees and healthy individuals. We measured the serum levels ACE2, AngII, CTSL, TNFα and humoral biomarkers (CD40L, IL-28A, IL-10, IL-33) by the ELISA method. Immunophenotyping of lymphocyte subpopulations was performed by flow cytometry. Total serum immunoglobulins were analyzed by the turbidimetry method. The results established an increase in the total serum levels for ACE2, CTSL, AngII and TNFα by severely ill patients and vaccinated persons. The correlation analysis described a positive relationship between ACE2 and proinflammatory cytokines IL-33 (r = 0.539) and CD40L (r = 0.520), a positive relationship between AngII and CD40L (r = 0.504), as well as between AngII and IL-33 (r = 0.416), and a positive relationship between CTSL, total IgA (r = 0.437) and IL-28A (r = 0.592). Correlation analysis confirmed only two of the positive relationships between TNFα and IL-28A (r = 0.491) and CD40L (r = 0.458). In summary, the findings presented in this study unveil a complex web of interactions within the immune system in response to SARS-CoV-2 infection and vaccination.

ACE2, ACE, DPPIV, PREP and CAT L enzymatic activities in COVID-19: imbalance of ACE2/ACE ratio and potential RAAS dysregulation in severe cases.

Circulating enzymatic activity and RAAS regulation in severe cases of COVID-19 remains unclear, therefore we measured the serum activity of several proteases as potential targets to control the SARS-CoV-2 infection. 152 patients with COVID-19-like symptoms were grouped according to the severity of symptoms (COVID-19 negative, mild, moderate and severe). Serum samples of COVID-19 patients and controls were subjected to biochemical analysis and enzymatic assays of ACE2, ACE, DPPIV, PREP and CAT L. One-way ANOVA and multivariate logistic regression analysis were used. Statistical significance was accepted at p < 0.05. We detected a positive correlation among comorbidities, higher C-reactive protein (CRP) and D-dimer levels with disease severity. Enzymatic assays revealed an increase in serum ACE2 and CAT L activities in severe COVID-19 patients, while ACE, DPPIV and PREP activities were significantly reduced. Notably, analysis of ACE2/ACE activity ratio suggests a possible imbalance of ANG II/ANG(1-7) ratio, in a positive association with the disease severity. Our findings reveal a correlation between proteases activity and the severity of COVID-19. These enzymes together contribute to the activation of pro-inflammatory pathways, trigger a systemic activation of inflammatory mediators, leading to a RAAS dysregulation and generating a significant damage in several organs, contributing to poor outcomes of severe cases.

Sex-specific splenic inflammation underlies sexual dimorphic effects of ACE2 in hypertension

Introduction: Sex differences in salt-sensitive hypertension and pharmacotherapy are commonly recognized. However, the mechanisms are largely unknown. ACE inhibitor is less effective in females than males, suggesting a better protective mechanism of the renin angiotensin system (RAS) in female hypertension. Angiotensin converting enzyme (ACE) 2, located on the X chromosome, is thereby a central candidate of sex differences in hypertension and pharmacotherapy. Thus, our objective is to test the sex specific protective role of ACE2 in salt hypertension. Since the females have a more regulatory RAS than males, we hypothesized that absence of ACE2 resulted in a higher blood pressure and more inflammation in females than males. Methods: ACE2 exon 2 was globally deleted using CRISPR/Cas9, resulting in a novel rat model in the Dahl salt-sensitive (S) background: male Ace2-/y and female Ace2-/+, Ace2-/-. Blood pressure was measured by telemetry in male (S n=7; S Ace2-/y n=6) and female (S n=7; Ace2-/+ n=7; Ace2-/- n=5) rats on 3 weeks high salt diets. Serum ACE2 activity was measured using ELISA. Spleen as the harbor of systemic immunity was studied for Inflammatory markers by gene expression analysis and flow cytometry. Results: Compared to sex-matched S rats, (1) serum ACE2 activity was decreased in female Ace2-/- (0.28 fold, p&lt;0.0001) and male Ace2-/y (0.3 fold, p&lt;0.0001); (2) systolic blood pressure was increased in female Ace2-/- (+67.89 mmHg, p&lt;0.0001) and male Ace2-/y (+48.64 mmHg, p&lt;0.0001) rats. Importantly, a sex-specific upregulation of the pro-inflammatory cytokines were found exclusively in the female Ace2-/- rat spleens: Il6 (1.8 fold, p&lt;0.05), Il1b (2.1 fold, p&lt;0.05) and Il17rc (2.3 fold, p&lt;0.01). In contrast, male Ace2-/y rats showed no difference in Il6 and Il1b, but downregulation of the splenic Il17rc (0.78 fold, p&lt;0.05), Th17 cells (IL17a on CD4+ cells, 0.76 fold, p&lt;0.01), regulatory T cells (FOXP3 on CD4+ cells, 0.49 fold, p&lt;0.01), CD68+ macrophage (0.76 fold, p&lt;0.01) and CD11bc+ dendritic cells (0.89 fold, p&lt;0.001).Furthermore, compared with female S rats, heterozygous female Ace2-/+ rats had decreased serum ACE2 activity (0.6 fold, p&lt;0.001), rescued blood pressure increase (+7.5 mmHg, p&lt;0.0001) and no increases in splenic inflammatory cytokines Il6, Il1b and Il17rc. Conclusions: Despite significantly lower serum ACE2 activity in heterozygous female Ace2-/+ rats, the protection in blood pressure and splenic inflammation was mainly preserved. This suggests a protective role of ACE2, beyond RAS, in inflammation-associated high blood pressure. Moreover, this novel protective role of ACE2 is exclusively in female salt hypertension, evidenced by greater increases in systolic blood pressure and splenic inflammation in female only. NIH R21AI164449 and R21AG079357. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The effect of omega-3 supplements on the serum levels of ACE/ACE2 ratio as a potential key in cardiovascular disease: A randomized clinical trial in participants with vitamin D deficiency.

The aim of this randomized controlled clinical trial was to determine the effect of the omega-3 fatty acid supplementations 300 mg per day for 8 weeks on the serum levels of ACE/ACE2 ratio in Jordanian participants with vitamin D deficiency (VDD). The physical and clinical characteristic of individuals in both intervention and control randomized controlled clinical trial were measured and analyzed. The comparisons between the two groups and the changes in each group before and after taking omega-3 doses were studied through independent t test and paired t test, respectively. Possible factors that have a role in the changes were determined by multivariate stepwise regression. Follow-up period lasted 10 weeks. The sample consisted of 82 participants with VDD and a mean age of 37.85 ± 9.85 years. Omega-3 Supplements resulted in a significant decrease in serum ACE levels, ACE/ACE2 ratio and serum 25-hydroxy vitamin D (25OHD). While the change in serum ACE2 levels and serum triglycerides levels were insignificant. Also, a significant increase in serum LDL levels were observed. It is possible that taking high doses of omega-3 fatty acid supplementations have positive effects on the heart and circulatory system and could protect from COVID-19 or decrease disease severity, in connection with a decrease in the ACE/ACE 2 ratio. On the other hand, omega-3 supplement may have negative effect on cardiovascular system due to the significant increase in serum LDL levels.

Role of Vitamin D, ACE2 and the Proteases as TMPRSS2 and Furin on SARS-CoV-2 Pathogenesis and COVID-19 Severity

COVID-19, the 21st century pandemic disease caused by SARS-CoV-2, has shown a wide clinical spectrum ranging from asymptomatic to deadly serious pneumonia. In our study, the relationship between the pathogenesis and clinical severity of COVID-19 and vitamin D, ACE2, Furin and TMPRSS2 was investigated. Serum 25(OH)D, 1,25(OH)2D and ACE2 protein were measured in 85 COVID-19 cases, divided into 5 groups, according to disease severity, from asymptomatic to severe and including a healthy control group. Expression levels of ACE2, VDR, TMPRSS2 and Furin mRNAs in PBMC were also measured. The relationship of the parameters within each group, the severity of the disease and the effect on the patients' fate were investigated. Statistically significant differences were found between the severity of COVID-19 and all study parameters, except for serum 25(OH)D. A strong negative correlation was found between serum ACE2 protein, 1,25(OH)2D, and ACE2 mRNA, and disease severity, length of hospital stay and death/survival rate. Vitamin D deficiency increased the death risk by 5.6-fold (95% CI 0.75-41.47), and the levels of 1,25(OH)2D lower than 1 ng/mL increased the risk of death by 3.8-fold (95% CI 1.07-13.30). This study suggests that vitamin D supplementation could be beneficial in the treatment and/or prevention of COVID-19.

771 THE SERUM ACE2 MOLECULE IN SARS-COV2 / COVID-19 INFECTION AND ITS POTENTIAL PROGNOSTIC AND THERAPEUTIC ROLE (ACCEPT STUDY)

Abstract Background It is well known that the entry of the SARS- CoV-2 virus into cells is mediated by the binding between the virus Spike-glycoprotein (S) and the membrane ACE2-receptor (ACE2R). When SARS-CoV-2 binds to ACE2R, with subsequent membrane fusion and virus entry into the cell, a down-regulation of these receptors occurs. ACE2R downregulation plays a crucial role in the pulmonary and systemic inflammatory response. Also ACE2 deficiency is thought to play an important role in the pathogenesis of SARS-CoV-2 infection. The down-regulation of ACE2 induced by viral infection could be particularly harmful in subjects with pre-existing ACE2 deficiency, for example due to advanced age, the presence of DM, arterial hypertension or pre-existing heart disease, including HF. Literature data suggest an association between the patient's age and comorbidities and a greater risk of severe clinical course and with a worse prognosis. However, serious clinical pictures requiring hospitalization or leading to death have also been observed in young subjects or subjects without comorbidities. Aim of the Study we aimed to identify predicting factors of a higher risk in terms of severity of the clinical course and worse prognosis in the population of the Brescia area, affected by a large number of cases in the first period of COVID-19 outbreak. In particular, we aimed to verify whether there is correlation between levels of serum ACE2 (sACE2) and the risk of SARS-CoV-2 infection, as well as between sACE2 and the different severity of the clinical manifestations of COVID-19 in patients with and without CV diseases. Methods we consecutively enrolled subjects with previous documented SARS-CoV-2 infection and divided our sample into three groups: pts with asymptomatic course; pts with symptomatic course but without the need for hospitalization for COVID-19; pts with severe symptomatic course requiring hospitalization in intensive care unit. Blood samples were taken for sACE2 dosage. We compared the concentrations of sACE2 in these groups in relation to the age, clinical course, comorbidities, and ongoing therapies. Results at March 2022, we enrolled 178 pts, 51 (28%) were hospitalized for COVID-19, whereas 78 (44%) had symptomatic course without hospitalization and 49 (28%) were completely pauci-asymptomatic. Only 6 pts (4%) had myocarditis or pericarditis SARS-CoV-2-related. Between hospitalized pts, male sex (67%), older age and higher BMI were most frequent. Moreover, chronic heart failure (20%), a diagnosis of cardiopathy (29%) and AF or atrial flutter (22%) were most frequent (Table 1). Plasma concentrations of sACE2 will be dosed and analyzed in relation to the clinical characteristics of each patient. Perspectives ACCEPT study will help to clarify the relationship between ACE2 molecule, the risk of SARS-CoV2 infection and the severity of clinical presentation of COVID-19 in pts with or without CV diseases.

Could serum ACE2 levels predict infarct size in acute phase of ST-segment elevation myocardial infarction: a comparative study with classical biomarkers.

Serum ACE2 level in the acute phase of ST-segment elevation myocardial infarction may be an indicator of heart failure, however, limited studies have reported conflicting results. Therefore, in our study, we aimed to evaluate the relationship between serum ACE2 level and infarct size in the acute phase of ST-segment elevation myocardial infarction and compare the predictive value of ACE2 level with classical biomarkers. Sixty-six patients after the primary percutaneous coronary intervention were included in the study. For the measurement of serum ACE2 levels, blood samples were taken twice from the patients: in the first 24 hours and on the 5th day of the infarction, and once from 30 healthy volunteers. hs-cTnT, BNP, and CRP levels were measured daily, and their peak values were taken. On the 7th day of ST-segment elevation myocardial infarction, gSPECT was used with the 99mTc-MIBI method for assessment of infarct size. Baseline ACE2 values were found to be higher in patients compared to controls, and ACE2 values obtained on the 5th day were found to be higher than the baseline values in the patients. There was no significant correlation between serum ACE2 levels and the RSS (%), while peak levels of hs-cTnT, BNP, and CRP were assessed as predictive factors for the RSS (%). Although serum ACE2 levels increased in the acute phase of ST-segment elevation myocardial infarction, this increase was not associated with infarct size. Serum ACE2 level did not provide additional benefit to classical biomarkers for infarct size-related prognosis prediction.

Abstract 12017: The Prognostic Role of Genotypic Variants of ACE2 and TMPRSS2 Polymorphisms in SARS-CoV2 / COVID-19 Infection

BACKGROUND: the entry of the SARS-CoV-2 into cells is mediated by the binding between the virus Spike-glycoprotein and the membrane ACE2-receptor (ACE2-R). When SARS-CoV-2 binds to ACE2-R, a down-regulation of these receptors occurs, playing a crucial role in the inflammatory response. A dysregulation of the RAAS linked to a different expression of ACE2-R and TMPRSS2 gene polymorphisms and different levels of serum ACE2 (sACE2), could be associated with abnormal inflammatory and immune response to SARS-CoV-2 infection. AIM OF THE STUDY: we aimed to verify whether there is an association between the clinical course of COVID-19 pts and the presence of more frequent ACE2 and TMPRSS2 single-nucleotide polymorphisms (SNPs) and if sACE2 levels are related to specific ACE2 and TMPRSS2 polymorphic variants. Methods: we consecutively enrolled subjects with previous documented SARS-CoV-2 infection and divided our sample into three groups: pts with asymptomatic course; pts with symptomatic course without an hospitalization for COVID-19; pts with severe symptomatic course requiring hospitalization in ICU. Data about age, clinical course, comorbidities, and therapies were collected. Blood samples were taken for the genetic analysis of the most frequent SNPs of the ACE2-R and TMPRSS2 detected in Italian population, in particular genotypic variants TT and CC of ACE2 SNPs 1 and 5 (5% and 14% respectively) and genotypic variants TT and CC of TMPRSS2 SNPs 2 and 3 (rate of 50% and 30% respective). Results: among 178 pts enrolled up to March 2022, we have so far analyzed the genetic polymorphisms of 74 pts; 21 (28%) were hospitalized for COVID-19, 38 (51%) had symptomatic course without hospitalization and 15 (21%) were completely asymptomatics. We found that sACE2 levels were higher in genotypic variant CC of SNP 1 of TMPRSS2 gene. Considering that a high concentration of sACE2 outlines a proinflammatory condition, it could be hypothesized that the CC genotype may be a predisposing condition to the cytokine storm of COVID-19. PERSPECTIVES: Genetic analysis of ACE2 and TMPRSS2 SNPs will help to clarify the relationship between these polymorphic variant, sACE2 levels, risk of SARS-CoV2 infection and severity of clinical presentation of COVID-19 in pts with or without CV diseases.

Abstract 12023: The Serum ACE2 Molecule in SARS-CoV2 / COVID-19 Infection and Its Potential Prognostic and Therapeutic Role (ACCEPT Study)

BACKGROUND: It is well known that the entry of the SARS- CoV-2 into cells is mediated by the binding between the virus Spike-glycoprotein (S) and the membrane ACE2-receptor (ACE2R). When SARS-CoV-2 binds to ACE2R, a down-regulation of ACE2R occurs, playing a crucial role in the inflammatory response. Also ACE2 deficiency is thought to play an important role in the pathogenesis of SARS-CoV-2 infection, and could be particularly harmful in subjects with pre-existing ACE2 deficiency, for example due to advanced age, the presence of DM, arterial hypertension or pre-existing heart disease, including HF. AIM OF THE STUDY: we aimed to identify predicting factors of a higher risk in terms of severity of the clinical course and worse prognosis in the population of the Brescia area, affected by a large number of cases in the first period of COVID-19 outbreak. In particular, we aimed to verify whether there is correlation between levels of serum ACE2 (sACE2) and the risk of SARS-CoV-2 infection, as well as between sACE2 and the different severity of the clinical manifestations of COVID-19 in pts with and without CV diseases. Methods: we enrolled subjects with previous documented SARS-CoV-2 infection and divided they into three groups: pts with asymptomatic course; pts with symptomatic course but without the need for hospitalization for COVID-19; pts with severe symptomatic course requiring hospitalization in ICU. Blood samples were taken for sACE2 dosage. We compared the concentrations of sACE2 in these groups in relation to the age, clinical course, comorbidities, and ongoing therapies. Results: at March 2022, we enrolled 178 pts, 51 (28%) were hospitalized for COVID-19, whereas 78 (44%) had symptomatic course without hospitalization and 49 (28%) were completely pauci-asymptomatic. Only 6 pts (4%) had myocarditis or pericarditis SARS-CoV-2-related. Between hospitalized pts, male sex (67%), older age and higher BMI were most frequent. Moreover, chronic heart failure (20%), a diagnosis of cardiopathy (29%) and AF or atrial flutter (22%) were most frequent. PERSPECTIVES: ACCEPT study will help to clarify the relationship between ACE2 molecule, the risk of SARS-CoV2 infection and the severity of clinical presentation of COVID-19 in pts with or without CV diseases.

Protocol for a 30-day randomised, parallel-group, non-inferiority, controlled trial investigating the effects of discontinuing renin-angiotensin system inhibitors in patients with and without COVID-19: the RASCOVID-19 trial

IntroductionThe COVID-19 pandemic caused by the virus SARS-CoV has spread rapidly and caused damage worldwide. Data suggest a major overrepresentation of hypertension and diabetes among patients experiencing severe courses of...

Angiotensin Converting Enzyme Activity in Anti-TNF-Treated Rheumatoid Arthritis and Ankylosing Spondylitis Patients.

IntroductionAngiotensin-converting enzyme (ACE) and ACE2 have been implicated in the regulation of vascular physiology. Elevated synovial and decreased or normal ACE or ACE2 levels have been found in rheumatoid arthritis (RA). Very little is known about the effects of tumor necrosis factor α (TNF-α) inhibition on ACE or ACE2 homeostasis. In this study, we assessed the effects of one-year anti-TNF therapy on ACE and ACE2 production in RA and ankylosing spondylitis (AS) in association with other biomarkers.Patients and MethodsForty patients including 24 RA patients treated with either etanercept (ETN) or certolizumab pegol (CZP) and 16 AS patients treated with ETN were included in a 12-month follow-up study. Serum ACE levels were determined by commercial ELISA, while serum ACE2 activity was assessed using a specific quenched fluorescent substrate. Ultrasonography was performed to determine flow-mediated vasodilation (FMD), common carotid intima-media thickness (ccIMT) and arterial pulse-wave velocity (PWV) in all patients. In addition, CRP, rheumatoid factor (RF) and ACPA were also measured. All assessments were performed at baseline and 6 and 12 months after treatment initiation.ResultsAnti-TNF therapy increased ACE levels in the full cohort, as well as in the RA and AS subsets. ACE2 activity increased in the full cohort, while the ACE/ACE2 ratio increased in the full cohort and in the RA subset (p < 0.05). Uni- and multivariable regression analyses determined associations between ACE or ACE/ACE2 ratios at different time points and disease duration, CRP, RF, FMD and IMT (p < 0.05). ACE2 activity correlated with CRP. The changes of ACE or ACE2 over 12 months were determined by treatment together with either RF or FMD (p < 0.05).ConclusionsAnti-TNF treatment may increase ACE and ACE2 in the sera of RA and AS patients. ACE and ACE2 may be associated with disease duration, markers of inflammation and vascular pathophysiology. The effects of TNF inhibition on ACE and ACE2 may reflect, in part, the effects of these biologics on the cardiovascular system.

Acute Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Pregnancy Is Associated with Placental Angiotensin-Converting Enzyme 2 Shedding

While the human placenta may be infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the rate of fetal transmission is low, suggesting a barrier at the maternal-fetal interface. Angiotensin-converting enzyme (ACE)2, the main receptor for SARS-CoV-2, is regulated by a metalloprotease cleavage enzyme, a disintegrin and metalloprotease domain 17 (ADAM17). ACE2 is expressed in the human placenta, but its regulation in relation to maternal SARS-CoV-2 infection in pregnancy is not well understood. This study evaluated ACE2 expression, ADAM17 activity, and serum ACE2 abundance in a cohort of matched villous placental and maternal serum samples from control pregnancies (SARS-CoV-2 negative, n = 8) and pregnancies affected by symptomatic maternal SARS-CoV-2 infections in the second trimester [2nd Tri coronavirus disease (COVID), n = 8] and third trimester (3rd Tri COVID, n = 8). In 3rd Tri COVID compared with control and 2nd Tri COVID villous placental tissues, ACE2 mRNA expression was remarkably elevated; however, ACE2 protein expression was significantly decreased with a parallel increase in ADAM17 activity. Soluble ACE2 was also significantly increased in the maternal serum from 3rd Tri COVID infections compared with control and 2nd Tri COVID pregnancies. These data suggest that in acute maternal SARS-CoV-2 infections, decreased placental ACE2 protein may be the result of ACE2 shedding and highlights the importance of ACE2 for studies on SARS-CoV-2 responses at the maternal-fetal interface.

Soluble ACE2 and TMPRSS2 Levels in the Serum of Asthmatic Patients.

BackgroundAngiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2) are key proteins mediating viral entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although gene expressions of ACE2 and TMPRSS2 have been analyzed in various organs and diseases, their soluble forms have been less studied, particularly in asthma. Therefore, we aimed to measure circulating ACE2 and TMPRSS2 in the serum of asthmatics and examine their relationship with clinical characteristics.MethodsClinical data and serum samples of 400 participants were obtained from an asthma cohort. The soluble ACE2 (sACE2) and soluble TMPRSS2 (sTMPRSS2) level was measured by enzyme-linked immunosorbent assay, and the values underwent a natural log transformation. Associations between sACE2 and TMPRSS2 levels and various clinical variables were analyzed.ResultsThe patients younger than 70 years old, those with eosinophilic asthma (eosinophils ≥ 200 cells/µL), and inhaled corticosteroids (ICS) non-users were associated with higher levels of sACE2. Blood eosinophils and fractionated exhaled nitric oxide levels were positively correlated with serum ACE2. In contrast, lower levels of sTMPRSS2 were noted in patients below 70 years and those with eosinophilic asthma, while no association was noted between ICS use and sTMPRSS2. The level of sTMPRSS2 also differed according to sex, smoking history, coexisting hypertension, and forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio. The proportion of sputum neutrophils was positively correlated with sTMPRSS2, while the FEV1/FVC ratio reported a negative correlation with sTMPRSS2.ConclusionThe levels of ACE2 and TMPRSS2 were differently expressed according to age, ICS use, and several inflammatory markers. These findings suggest variable susceptibility and prognosis of SARS-CoV-2 infection among asthmatic patients.

Can Serum ACE Level Be Used as a Prognostic Indicator in COVID-19?

SARS-COV-2 virus that causes COVID-19 binds to the host cell with angiotensin converting enzyme-2 causing acute respiratory distress syndrome (ARDS) and severe mortality and morbidity. There are studies in the literature conducted on the importance of serum angiotensin converting enzyme (ACE) and ACE-2 enzymes in ARDS pathogenesis. Serum ACE levels are higher in children and adolescents than in adults, and COVID-19 has a milder progression. All these reasons suggest that there may be a relationship between serum ACE levels and COVID-19 prognosis. The serum ACE levels were determined at the time of hospitalization due to COVID-19 diagnosis in this single-centered, prospective study. According to discharge status, patients were divided into three groups as "Discharge with Healing", "Intensive Care Need" and "Mortality", and the effect of serum ACE levels on disease prognosis was investigated. The present study comprised a total of 103 patients, of whom 42.7% (n = 44) were female, and 57.3% (n = 59) were male. The mean age was 59.48 ± 16.47; 91.3% (n = 94) of them were discharged with healing, 5.8% (n = 6) needed intensive care, and 2.9% (n = 3) resulted in mortality. No differences were detected in terms of serum ACE levels between the groups. No relationships were detected between serum ACE levels at the time of hospitalization and COVID-19 prognosis.

Circulating ACE2 activity predicts mortality and disease severity in hospitalized COVID-19 patients

ObjectivesAngiotensin-converting enzyme 2 (ACE2) represents the primary receptor for SARS-CoV-2 to enter endothelial cells. Here we investigated circulating ACE2 activity to predict the severity and mortality of COVID-19. MethodsSerum ACE2 activity was measured in COVID-19 (110 critically ill and 66 severely ill subjects at hospital admission and 106 follow-up samples) and in 32 non-COVID-19 severe sepsis patients. Associations between ACE2, inflammation-dependent biomarkers, pre-existing comorbidities, and clinical outcomes were studied. ResultsInitial ACE2 activity was significantly higher in critically ill COVID-19 patients (54.4 [36.7-90.8] mU/L) than in severe COVID-19 (34.5 [25.2-48.7] mU/L; P<0.0001) and non-COVID-19 sepsis patients (40.9 [21.4-65.7] mU/L; P=0.0260) regardless of comorbidities. Circulating ACE2 activity correlated with inflammatory biomarkers and was further elevated during the hospital stay in critically ill patients. Based on ROC-curve analysis and logistic regression test, baseline ACE2 independently indicated the severity of COVID-19 with an AUC value of 0.701 (95% CI [0.621-0.781], P<0.0001). Furthermore, non-survivors showed higher serum ACE2 activity vs. survivors at hospital admission (P<0.0001). Finally, high ACE2 activity (≥45.4 mU/L) predicted a higher risk (65 vs. 37%) for 30-day mortality (Log-Rank P<0.0001). ConclusionsSerum ACE2 activity correlates with COVID-19 severity and predicts mortality.