Angiotensin converting enzyme 2 activity and human atrial fibrillation: increased plasma angiotensin converting enzyme 2 activity is associated with atrial fibrillation and more advanced left atrial structural remodelling

Effect of renin angiotensin blockers on angiotensin converting enzyme 2 level in cardiovascular patients

BACKGROUND

Renin-angiotensin-aldosterone system (RAAS) is hypothesized to be in the center of COVID pathophysiology as the angiotensin converting enzyme 2 (ACE2) represents the main entrance of the virus, thus there is a need to address the effect of chronic use of RAAS blockers, as in case of treatment of cardiovascular diseases, on the expression of ACE2. Accordingly, this study aimed to clarify the effect of ACE inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) on ACE2 and to assess the correlation between ACE2 and several anthropometric and clinic-pathological factors.

METHODS

A total of 40 healthy controls and 60 Egyptian patients suffering from chronic cardiovascular diseases were enrolled in this study. Patients were divided into 40 patients treated with ACEIs and 20 patients treated with ARBs. Serum ACE2 levels were assessed by ELISA.

RESULTS

Assessment of serum ACE2 level in different groups showed a significant difference between ACEIs and healthy groups and ACEIs and ARBs group, while there was no difference between ARBs and healthy. Multivariate analysis using ACE2 level as constant and age, female sex, ACEIs use and myocardial infarction (MI) showed that there was a significant effect of female sex and ACEIs use on ACE2 level with no effect of age, MI and diabetes.

CONCLUSION

ACE2 levels varied between ACEIs and ARBs. It tends to be lower in ACEIs group and there is a strong positive association between ACE2 level and the female sex. This needs to be considered in Future studies to further understand the relationship between gender, sex hormones and ACE2 level.

TRIAL REGISTRATION

Retrospectively registered ClinicalTrials.gov ID: NCT05418361 (June 2022).

Hypothesis: Efficacy of early treatments with some NSAIDs in COVID-19: Might it also depend on their direct and/or indirect zinc chelating ability?

The present work argues for the involvement of the zinc chelating ability of some non-steroidal anti-inflammatory drugs as an additive mechanism able to increase their efficacy against COVID-19.

Angiotensin converting enzyme 2 level and its significance in COVID-19 and other diseases patients

BACKGROUND

Angiotensin-converting enzyme 2 (ACE2) expressions and its modulation are of great interest as being a key receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) and the protective arm of the rennin-angiotensin axis, maintaining cardiovascular homeostasis. However, ACE2 expressions and their modulation in the healthy and disease background are yet to be explored.

METHOD

We performed a meta-analysis, extracting the data for ACE2 expression in human subjects with various diseases, including SARS-CoV2 infection without or with co-morbidity. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Out of 203 studies, 39 met the inclusion criteria with SARS-CoV2 patients without co-morbidity, SARS-CoV2 patients with co-morbidity, cardiovascular (CVD) patients, diabetes patients, kidney disorders patients, pulmonary disease patients, and other viral infections patients.

RESULTS

Angiotensin-converting enzyme 2 expression was significantly increased in all diseases. There was an elevated level of ACE2, especially membrane-bound ACE2, in COVID-19 patients compared to healthy controls. A statistically significant increase in ACE2 expression was observed in CVD patients and patients with other viral diseases compared to healthy subjects. Moreover, subgroup analysis of ACE2 expression as soluble and membrane-bound ACE2 revealed a remarkable increase in membrane-bound ACE2 in CVD patients, patients with viral infection compared to soluble ACE2 and pooled standard mean difference (SMD) with the random-effects model was 0.37 and 2.23 respectively.

CONCLUSION

It was observed that utilizing the ACE2 by SARS-CoV2 for its entry and its consequence leads to several complications. So there is a need to investigate the underlying mechanism along with novel therapeutic strategies.

Plasma Angiotensin Converting Enzyme 2 (ACE2) Activity in Healthy Controls and Patients with Cardiovascular Risk Factors and/or Disease

Angiotensin converting enzyme 2 (ACE2) is an endogenous negative regulator of the renin-angiotensin system, a key factor in the development of cardiovascular disease (CVD). ACE2 is also used by SARS-CoV-2 for host cell entry. Given that COVID-19 is associated with hypercoagulability, it is timely to explore the potential relationship between plasma ACE2 activity and the coagulation profile. In this cross-sectional study, ACE2 activity and global coagulation assays (GCA) including thromboelastography, thrombin, and fibrin generation were measured in adult healthy controls (n = 123; mean age 41 ± 17 years; 35% male) and in patients with cardiovascular risk factors and/or disease (n = 258; mean age 65 ± 14 years; 55% male). ACE2 activity was significantly lower in controls compared to patients with cardiovascular risk factors and/or disease (median 0.10 (0.02, 3.33) vs. 5.99 (1.95, 10.37) pmol/mL/min, p < 0.001). Of the healthy controls, 48% had undetectable ACE2 activity. Controls with detectable ACE2 had lower maximum amplitude (p < 0.001). In patients with cardiovascular risk factors and/or disease, those in the 3rd tertile were older and male (p = 0.002), with a higher Framingham grade and increased number of cardiovascular risk factors (p < 0.001). In conclusion, plasma ACE2 activity is undetectable to very low in young healthy controls with minimal clinically relevant associations to GCA. Patients with cardiovascular risk factors and/or disease have increased plasma ACE2 activity, suggesting that it may be an important biomarker of endothelial dysfunction and atherosclerosis.

Higher serum sST2 is associated with increased left atrial low-voltage areas and atrial fibrillation recurrence in patients undergoing radiofrequency ablation

OBJECTIVE

To conduct a comprehensive analysis of prospectively measuring the concentration of soluble suppression of tumorigenicity 2 (sST2) to predict left atrial (LA) low-voltage areas (LVAs) and atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFA).

METHODS

This was a prospective cohort study. A total of 84 patients, including 54 paroxysmal AF cases and 30 persistent AF cases who underwent RFA, were recruited. Electroanatomical voltage mapping determined the extent of LVAs. The serum level of sST2 was measured by enzyme-linked immunosorbent assay. All patients were followed for 12 months after the RFA procedure to verify AF recurrence.

RESULTS

The concentration of sST2 measured in the sample was 17.90-198.77 pg/mL, and the range of LA LVAs was 0-85.6%. The sST2 level positively correlated with LVAs (r = 0.40; P = 0.005). When comparing the top and bottom quartile, sST2 is significantly associated with LA LVAs (OR = 1.833, 95% CI: 1.582-2.011, P = 0.004). When compared with the 1st quartile group, the multivariable adjusted hazard ratios for AF recurrence after RFA were 1.57 (95% CI: 1.182-1.795) for the 4th quartile group, 1.44 (95% CI: 1.085-1.598) for the 3rd quartile group, and 1.27 (95% CI: 0.954-1.318) for the 2nd quartile group. The AF-free survival rates of patients with 1st quartile and 4th quartile sST2 levels after ablation were 95% and 59.6%, respectively (Log Rank test, P = 0.027).

CONCLUSION

Elevated sST2 levels of AF patients were associated with higher LA LVAs and a significantly increased risk of recurrence. The circulating sST2 concentration might be a pre-diagnostic marker of AF recurrence after RFA.

COVID-19 and cardiovascular disease: manifestations, pathophysiology, vaccination, and long-term implication

The coronavirus disease 2019 (COVID-19) pandemic is caused by a new coronavirus family member, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is linked with many disease manifestations in multiple organ systems on top of pulmonary manifestations. COVID-19 is also accompanied by several cardiovascular pathologies including myocarditis, acute myocardial infarction, stress cardiomyopathy, arterial and venous thromboembolism, pericarditis, and arrhythmias. The pathophysiological mechanisms explaining these clinical symptoms are multifactorial including systemic inflammation (cytokine storm), coagulopathy, direct viral invasion through angiotensin-converting enzyme 2, hypoxemia, electrolyte imbalance, and fever. Several case reports have shown the development of an unusual cardiovascular event after receiving SARS-CoV-2 vaccines. The current article aimed to review cardiovascular involvement in the COVID-19 pandemic with respect to clinical features, pathogenesis, long-term effects, and the adverse effects of treatments and vaccines based on the latest evidence.

Evaluating the role of transthoracic echocardiography in hospitalised patients with COVID-19 infection

Objective

To identify the most common transthoracic echocardiogram (TTE) parameters in patients hospitalised with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2/COVID-19) and their association with myocardial injury and outcomes.

Methods

A retrospective, single-centre, observational, exploratory cohort study was performed at the height of the COVID-19 pandemic. All SARS-CoV-2 polymerase chain reaction (PCR) positive patients who underwent a TTE during their inpatient admission between 1 March 2020 and 31 October 2020 were analysed. The most frequent cardiovascular risk factor profile and echocardiographic features were investigated.

Results

A total of 87 patients met the eligibility criteria. A salient 41.4% (n=36) of our cohort succumbed to this devastating virus. More than half of our hospital population (58.6%) were admitted to the intensive care unit (ITU) and this was significantly associated with inpatient mortality (OR: 7.14, CI 2.53 to 20.19, p<0.001). Hypertension was the most common cardiovascular risk factor (51.7%) with no additional prominence in non-survivors (OR: 2.33, CI 0.97 to 5.61, p=0.059). Remarkably, 90.8% of our cohort demonstrated a preserved left ventricular ejection fraction, although 69.1% had elevated troponin levels. Only 1 patient (1.1%) was given a diagnostic label of myocarditis. A raised pulmonary artery systolic pressure (36.8%) andright ventricle (RV) dysfunction (26.4%) were the most common echocardiographic features. In particular, the presence of RV dysfunction was significantly related to adverse outcomes (OR: 2.97, CI 1.11 to 7.94, p<0.03).

Conclusions

In this cohort of extremely unwell patients hospitalised with COVID-19 pneumonitis, the presence of RV dysfunction or admission to ITU was significantly associated with inpatient case fatality ratio. Moreover, COVID-19-induced myocarditis remains extremely rare.

Clinical Outcome of Hospitalized COVID-19 Patients with History of Atrial Fibrillation

Background and objectives: Pre-existing atrial fibrillation (AF) is a frequent comorbidity in hospitalized patients with COVID-19; however, little is still known about its prognostic role in infected patients. The aim of our study was to evaluate whether the pre-existing AF as comorbidity would contribute to increase the risk for severe forms of COVID-19, worse prognosis, or even higher mortality. Materials and Methods: We retrospectively evaluated all consecutive COVID-19 patients admitted to the emergency department of nine Italian Hospitals from 1 March to 30 April 2020.The prevalence and the type of pre-existing AF have been collected. The correlation between the history and type of AF and the development of severe ARDS and in-hospital mortality has been evaluated. Results: In total, 467 patients (66.88 ± 14.55 years; 63% males) with COVID-19 were included in the present study. The history of AF was noticed in 122 cases (26.1%), of which 12 (2.6%) with paroxysmal, 57 (12.2%) with persistent and 53 (11.3%) with permanent AF. Among our study population, COVID-19 patients with AF history were older compared to those without AF history (71.25 ± 12.39 vs. 65.34 ± 14.95 years; p < 0.001); however, they did not show a statistically significant difference in cardiovascular comorbidities or treatments. Pre-existing AF resulted in being independently associated with an increased risk of developing severe ARDS during the hospitalization; in contrast, it did not increase the risk of in-hospital mortality. Among patients with AF history, no significant differences were detected in severe ARDS and in-hospital mortality between patients with permanent and non-permanent AF history. Conclusions: Pre-existing AF is a frequent among COVID-19 patients admitted to hospital, accounting up to 25% of cases. It is independently associated with an increased risk of severe ARDS in hospitalized COVID-19 patients; in contrast, it did not affect the risk of death. The type of pre-existing AF (permanent or non-permanent) did not impact the clinical outcome.

Calcium Signaling Pathway Is Involved in the Shedding of ACE2 Catalytic Ectodomain: New Insights for Clinical and Therapeutic Applications of ACE2 for COVID-19

The angiotensin-converting enzyme 2 (ACE2) is a type I integral membrane that exists in two forms: the first is a transmembrane protein; the second is a soluble catalytic ectodomain of ACE2. The catalytic ectodomain of ACE2 undergoes shedding by a disintegrin and metalloproteinase domain-containing protein 17 (ADAM17), in which calmodulin mediates the calcium signaling pathway that is involved in ACE2 release, resulting in a soluble catalytic ectodomain of ACE2 that can be measured as soluble ACE2 plasma activity. The shedding of the ACE2 catalytic ectodomain plays a role in cardiac remodeling and endothelial dysfunction and is a predictor of all-cause mortality, including cardiovascular mortality. Moreover, considerable evidence supports that the ACE2 catalytic ectodomain is an essential entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Additionally, endotoxins and the pro-inflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-alpha (TNFα) all enhanced soluble catalytic ectodomain ACE2 shedding from the airway epithelia, suggesting that the shedding of ACE2 may represent a mechanism by which viral entry and infection may be controlled such as some types of betacoronavirus. In this regard, ACE2 plays an important role in inflammation and thrombotic response, and its down-regulation may aggravate COVID-19 via the renin-angiotensin system, including by promoting pathological changes in lung injury. Soluble forms of ACE2 have recently been shown to inhibit SARS-CoV-2 infection. Furthermore, given that vitamin D enhanced the shedding of ACE2, some studies reported that vitamin D treatment is associated with prognosis improvement in COVID-19. This is an updated review on the evidence, clinical, and therapeutic applications of ACE2 for COVID-19.

Identification and Development of Therapeutics for COVID-19

After emerging in China in late 2019, the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread worldwide, and as of mid-2021, it remains a significant threat globally. Only a few coronaviruses are known to infect humans, and only two cause infections similar in severity to SARS-CoV-2: Severe acute respiratory syndrome-related coronavirus, a species closely related to SARS-CoV-2 that emerged in 2002, and Middle East respiratory syndrome-related coronavirus, which emerged in 2012. Unlike the current pandemic, previous epidemics were controlled rapidly through public health measures, but the body of research investigating severe acute respiratory syndrome and Middle East respiratory syndrome has proven valuable for identifying approaches to treating and preventing novel coronavirus disease 2019 (COVID-19). Building on this research, the medical and scientific communities have responded rapidly to the COVID-19 crisis and identified many candidate therapeutics. The approaches used to identify candidates fall into four main categories: adaptation of clinical approaches to diseases with related pathologies, adaptation based on virological properties, adaptation based on host response, and data-driven identification (ID) of candidates based on physical properties or on pharmacological compendia. To date, a small number of therapeutics have already been authorized by regulatory agencies such as the Food and Drug Administration (FDA), while most remain under investigation. The scale of the COVID-19 crisis offers a rare opportunity to collect data on the effects of candidate therapeutics. This information provides insight not only into the management of coronavirus diseases but also into the relative success of different approaches to identifying candidate therapeutics against an emerging disease. IMPORTANCE The COVID-19 pandemic is a rapidly evolving crisis. With the worldwide scientific community shifting focus onto the SARS-CoV-2 virus and COVID-19, a large number of possible pharmaceutical approaches for treatment and prevention have been proposed. What was known about each of these potential interventions evolved rapidly throughout 2020 and 2021. This fast-paced area of research provides important insight into how the ongoing pandemic can be managed and also demonstrates the power of interdisciplinary collaboration to rapidly understand a virus and match its characteristics with existing or novel pharmaceuticals. As illustrated by the continued threat of viral epidemics during the current millennium, a rapid and strategic response to emerging viral threats can save lives. In this review, we explore how different modes of identifying candidate therapeutics have borne out during COVID-19.

Alternative RAS in Various Hypoxic Conditions: From Myocardial Infarction to COVID-19

Alternative branches of the classical renin–angiotensin–aldosterone system (RAS) represent an important cascade in which angiotensin 2 (AngII) undergoes cleavage via the action of the angiotensin-converting enzyme 2 (ACE2) with subsequent production of Ang(1-7) and other related metabolites eliciting its effects via Mas receptor activation. Generally, this branch of the RAS system is described as its non-canonical alternative arm with counterbalancing actions to the classical RAS, conveying vasodilation, anti-inflammatory, anti-remodeling and anti-proliferative effects. The implication of this branch was proposed for many different diseases, ranging from acute cardiovascular conditions, through chronic respiratory diseases to cancer, nonetheless, hypoxia is one of the most prominent common factors discussed in conjugation with the changes in the activity of alternative RAS branches. The aim of this review is to bring complex insights into the mechanisms behind the various forms of hypoxic insults on the activity of alternative RAS branches based on the different duration of stimuli and causes (acute vs. intermittent vs. chronic), localization and tissue (heart vs. vessels vs. lungs) and clinical relevance of studied phenomenon (experimental vs. clinical condition). Moreover, we provide novel insights into the future strategies utilizing the alternative RAS as a diagnostic tool as well as a promising pharmacological target in serious hypoxia-associated cardiovascular and cardiopulmonary diseases.

Soluble angiotensin-converting enzyme levels in heart failure or acute coronary syndrome: revisiting its modulation and prognosis value

The main objective was to compare the meaning of soluble angiotensin-converting enzyme-2 (sACE2) plasma levels modulation on the prognosis of two cohorts of heart failure (HF) and acute coronary syndrome (ACS). We conducted an observational clinical study where sACE2 was measured in two cohorts of HF or ACS (102 patients each), matched by age and gender. The primary endpoint (cardiac death) and the secondary endpoints (non-fatal myocardial infarction or HF readmission) were registered during a 5-year follow-up period. Association with pharmacotherapy was studied, and the effects of cardiovascular drugs on ACE isoforms expression were analysed in human umbilical vein endothelial cells (HUVEC) in vitro. The levels of sACE2 were significantly higher in the HF than ACS cohort. sACE2 was inversely related with the leukocytes number and directly with urea levels. In the ACS cohort, sACE2 was associated with age and glycaemic parameters, but in the HF cohort, the association was with N-terminal pro-B-type natriuretic peptide. The levels of sACE2 were related to long-term prognosis and confirmed as a non-independent predictor in the HF cohort. Soluble ACE2 was higher in patients treated with angiotensin receptors blockers and β-blockers, accordingly with losartan and metoprolol upregulation of ACE1 and ACE2 in HUVECs. Plasma levels of sACE2 were higher in HF than in ACS, independently of age and gender, and were related to long-term cardiac death in the HF cohort. Losartan and metoprolol, but not enalapril, upregulated ACE expression in endothelial cells, accordingly with higher levels of sACE2 in patients using these drugs.

Left atrial strain measured by 4D Auto LAQ echocardiography is significantly correlated with high risk of thromboembolism in patients with non-valvular atrial fibrillation

Background

The 4-dimensional automated left atrial quantification (4D Auto LAQ) tool is a new software for analysis of the structure and function of the left atrium (LA). This study aimed to evaluate the relationship between LA strain (LAS) as measured by 4D Auto LAQ echocardiography and thromboembolism risk in patients with non-valvular atrial fibrillation (NVAF).

Methods

Eight-five patients with NVAF were recruited from the cardiovascular center of our hospital, including 39 patients at high risk and 46 patients at low risk of thromboembolism. The study participants were assessed by routine echocardiography; 4D images were obtained, after which 4D Auto LAQ assessment was performed.

Results

In the thromboembolism high-risk group, the rates of impaired LA reservoir strain, LA contraction strain, LA reservoir circumferential strain, LA conduit circumferential strain, and LA contraction circumferential strain were found to be significantly higher than in the low-risk group. However, there was no significant difference in volume at onset of LA contraction or LA ejection fraction (LAEF) between the 2 groups. LA contraction circumferential strain was found to be an independent high risk factor for thromboembolism [odds ratio (OR): 2.52; P=0.008]. LA contraction circumferential strain >-4.5% was the cut-off for differentiating between participants with high and low risk of thromboembolism, with an area under the curve (AUC) of 0.95 (P<0.0001), a sensitivity of 0.872, and a specificity of 0.978. Sequential analysis revealed that LA contraction circumferential strain had a high diagnostic efficacy for stroke, as well as a specified accuracy in the diagnosis of hypertension and diabetes in patients aged ≥65 years old. However, it was not found to be effective in the diagnosis of heart failure and vascular diseases.

Conclusions

LAS is a useful index for the dynamic evaluation of LA function in patients with non-valvular AF, with higher sensitivity and accuracy than LA volume. LA contraction circumferential strain is an independent high risk factor for thromboembolism, and LA contraction circumferential strain >-4.5% is a valuable cut-off to guide the use of anticoagulant therapy in patients with non-valvular AF.

Cardiovascular system and coronavirus disease-2019 (COVID-19): mutual injuries and unexpected outcomes

BACKGROUND

Cardiovascular system involvement in coronavirus disease-2019 (COVID-19) has gained great interest in the scientific community.

MAIN BODY

Several studies reported increased morbidity and mortality among COVID-19 patients who had comorbidities, especially cardiovascular diseases like hypertension and acute coronary syndrome (ACS). COVID-19 may be associated with cardiovascular complications as arrhythmia, myocarditis, and thromboembolic events. We aimed to illustrate the interactions of COVID-19 disease and the cardiovascular system and the consequences on clinical decision as well as public health.

CONCLUSIONS

COVID-19 has negative consequences on the cardiovascular system. A high index of suspicion should be present to avoid poor prognosis of those presenting with unusual presentation.

Can Host Cell Proteins Like ACE2, ADAM17, TMPRSS2, Androgen Receptor be the Efficient Targets in SARS-CoV-2 Infection?

A novel betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV- -2), which caused a large disease outbreak in Wuhan, China in December 2019, is currently spreading across the world. Along with binding of the virus spike with the host cell receptor, fusion of the viral envelope with host cell membranes is a critical step in establishing successful infection of SARS-CoV-2. In this entry process, a diversity of host cell proteases and androgen receptor play a very important role directly or indirectly. These features of SARS-CoV-2 entry contribute to its rapid spread and severe symptoms, high fatality rates among infected patients. This review is based on the latest published literature including review articles, research articles, hypothetical manuscript, preprint articles and official documents. The literature search was made from various published papers on physiological aspects relevant to SARS-CoV and SARS-CoV-2. In this report, we focus on the role of host cell proteases (ACE2, ADAM17, TMPRSS2) and androgen receptor (AR) in SARS-CoV-2 infection. The hypotheses put forth by us are based on the role played by the proteases ACE2, ADAM17, TMPRSS2 and AR in SARS-CoV-2 infection, which were deduced based on various studies. We have also summarized how these host proteins increase the pathology and the infective ability of SARS-CoV-2 and we posit that their inhibition may be a therapeutic option for preventing SARS-CoV-2 infection.

Imaging of Coronavirus Disease 2019 Infection From Head to Toe: A Primer for the Radiologist

Coronavirus Disease 2019 (COVID-19) disease has rapidly spread around the world after initial identification in Wuhan, China, in December 2019. Most common presentation is mild or asymptomatic disease, followed by pneumonia, and rarely- multiorgan failure and Acute Respiratory Distress Syndrome (ARDS). Knowledge about the pathophysiology, imaging and treatment of this novel virus is rapidly evolving due to ongoing worldwide research. Most common imaging modalities utilized during this pandemic are chest radiography and HRCT with findings of bilateral peripheral, mid and lower zone GGO and/or consolidation, vascular enlargement and crazy paving. HRCT is also useful for prognostication and follow-up of severely ill COVID-19 patients. Portable radiography allows follow-up of ICU patients & obviates the need of shifting critically ill patients and disinfection of CT room. As the pandemic has progressed, numerous neurologic manifestations have been described in COVID-19 including stroke, white matter hyperintensities and demyelination on MRI. Varying abdominal presentations have been described, which on imaging either show evidence of COVID-19 pneumonia in lung bases or show abdominal findings including bowel thickening and vascular thrombosis. Numerous thrombo-embolic and cardiovascular complications have also been described in COVID-19 including arterial and venous thrombosis, pulmonary embolism and myocarditis. It is imperative for radiologists to be aware of all the varied faces of this disease on imaging, as they may well be the first physician to suspect the disease. This article aims to review the multimodality imaging manifestations of COVID-19 disease in various organ systems from head to toe.

[Atrial fibrillation in patients with COVID-19. Usefulness of the CHA2DS2-VASc score: an analysis of the international HOPE COVID-19 registry]

INTRODUCTION AND OBJECTIVES

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2. Atrial fibrillation (AF) is common in acute situations, where it is associated with more complications and higher mortality.

METHODS

Analysis of the international HOPE registry (NCT04334291). The objective was to assess the prognostic information of AF in COVID-19 patients. A multivariate analysis and propensity score matching were performed to assess the relationship between AF and mortality. We also evaluated the impact on mortality and embolic events of the CHA2DS2-VASc score in these patients.

RESULTS

Among 6217 patients enrolled in the HOPE registry, 250 had AF (4.5%). AF patients had a higher prevalence of cardiovascular risk factors and comorbidities. After propensity score matching, these differences were attenuated. Despite this, patients with AF had a higher incidence of in-hospital complications such as heart failure (19.3% vs 11.6%, P = .021) and respiratory insufficiency (75.9% vs 62.3%, P = .002), as well as a higher 60-day mortality rate (43.4% vs 30.9%, P = .005). On multivariate analysis, AF was independently associated with higher 60-day mortality (hazard ratio, 1.234; 95%CI, 1.003-1.519). CHA2DS2-VASc score acceptably predicts 60-day mortality in COVID-19 patients (area ROC, 0.748; 95%CI, 0.733-0.764), but not its embolic risk (area ROC, 0.411; 95%CI, 0.147-0.675).

CONCLUSIONS

AF in COVID-19 patients is associated with a higher number of complications and 60-day mortality. The CHA2DS2-VASc score may be a good risk marker in COVID patients but does not predict their embolic risk.

Atrial fibrillation in patients with COVID-19. Usefulness of the CHA2DS2-VASc score: an analysis of the international HOPE COVID-19 registry

INTRODUCTION AND OBJECTIVES

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2. Atrial fibrillation (AF) is common in acute situations, where it is associated with more complications and higher mortality.

METHODS

Analysis of the international HOPE registry (NCT04334291). The objective was to assess the prognostic information of AF in COVID-19 patients. A multivariate analysis and propensity score matching were performed to assess the relationship between AF and mortality. We also evaluated the impact on mortality and embolic events of the CHA2DS2-VASc score in these patients.

RESULTS

Among 6217 patients enrolled in the HOPE registry, 250 had AF (4.5%). AF patients had a higher prevalence of cardiovascular risk factors and comorbidities. After propensity score matching, these differences were attenuated. Despite this, patients with AF had a higher incidence of in-hospital complications such as heart failure (19.3% vs 11.6%, P=.021) and respiratory insufficiency (75.9% vs 62.3%, P=.002), as well as a higher 60-day mortality rate (43.4% vs 30.9%, P=.005). On multivariate analysis, AF was independently associated with higher 60-day mortality (hazard ratio, 1.234; 95%CI, 1.003-1.519). CHA2DS2-VASc score acceptably predicts 60-day mortality in COVID-19 patients (area ROC, 0.748; 95%CI, 0.733-0.764), but not its embolic risk (area ROC, 0.411; 95%CI, 0.147-0.675).

CONCLUSIONS

AF in COVID-19 patients is associated with a higher number of complications and 60-day mortality. The CHA2DS2-VASc score may be a good risk marker in COVID patients but does not predict their embolic risk.

Do Changes in ACE-2 Expression Affect SARS-CoV-2 Virulence and Related Complications: A Closer Look into Membrane-Bound and Soluble Forms

The SARS-CoV-2 virus utilizes angiotensin converting enzyme (ACE-2) for cell entry and infection. This enzyme has important functions in the renin-angiotensin aldosterone system to preserve cardiovascular function. In addition to the heart, it is expressed in many tissues including the lung, intestines, brain, and kidney, however, its functions in these organs are mostly unknown. ACE-2 has membrane-bound and soluble forms. Its expression levels are altered in disease states and by a variety of medications. Currently, it is not clear how altered ACE-2 levels influence ACE-2 virulence and relevant complications. In addition, membrane-bound and soluble forms are thought to have different effects. Most work on this topic in the literature is on the SARS-CoV virus that has a high genetic resemblance to SARS-Co-V-2 and also uses ACE-2 enzyme to enter the cell, but with much lower affinity. More recent studies on SARS-CoV-2 are mainly clinical studies aiming at relating the effect of medications that are thought to influence ACE-2 levels, with COVID-19 outcomes for patients under these medications. This review paper aims to summarize what is known about the relationship between ACE-2 levels and SARS-CoV/SARS-CoV-2 virulence under altered ACE-2 expression states.

Assessment of Autonomic Nervous System Dysfunction in the Early Phase of Infection With SARS-CoV-2 Virus

BACKGROUND

We are facing the outburst of coronavirus disease 2019 (COVID-19) defined as a serious, multisystem, disorder, including various neurological manifestations in its presentation. So far, autonomic dysfunction (AD) has not been reported in patients with COVID-19 infection.

AIM

Assessment of AD in the early phase of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus).

PATIENTS AND METHODS

We analyzed 116 PCR positive COVID-19 patients. After the exclusion of 41 patients with associate diseases (CADG), partitioned to patients with diabetes mellitus, hypertension, and syncope, the remaining patients were included into a severe group (45 patients with confirmed interstitial pneumonia) and mild group (30 patients). Basic cardiovascular autonomic reflex tests (CART) were performed, followed by beat-to-beat heart rate variability (HRV) and systolic and diastolic blood pressure variability (BPV) analysis, along with baroreceptor sensitivity (BRS). Non-linear analysis of HRV was provided by Poincare Plot. Results were compared to 77 sex and age-matched controls.

RESULTS

AD (sympathetic, parasympathetic, or both) in our study has been revealed in 51.5% of severe, 78.0% of mild COVID-19 patients, and the difference compared to healthy controls was significant (p = 0.018). Orthostatic hypotension has been established in 33.0% COVID-19 patients compared to 2.6% controls (p = 0.001). Most of the spectral parameters of HRV and BPV confirmed AD, most prominent in the severe COVID-19 group. BRS was significantly lower in all patients (severe, mild, CADG), indicating significant sudden cardiac death risk.

CONCLUSION

Cardiovascular autonomic neuropathy should be taken into account in COVID-19 patients' assessment. It can be an explanation for a variety of registered manifestations, enabling a comprehensive diagnostic approach and further treatment.

A comprehensive review on clinical and mechanistic pathophysiological aspects of COVID-19 Malady: How far have we come?

Since its outbreak in 2019, the coronavirus disease (COVID-19) has become a pandemic, affecting more than 52 million people and causing more than 1 million mortalities globally till date. Current research reveals a wide array of disease manifestations and behaviors encompassing multiple organ systems in body and immense systemic inflammation, which have been summarized in this review. Data from a number of scientific reviews, research articles, case series, observational studies, and case reports were retrieved by utilizing online search engines such as Cochrane, PubMed, and Scopus from December 2019 to November 2020. The data for prevalence of signs and symptoms, underlying disease mechanisms and comorbidities were analyzed using SPSS version 25. This review will discuss a wide range of COVID-19 clinical presentations recorded till date, and the current understanding of both the underlying general as well as system specific pathophysiologic, and pathogenetic pathways. These include direct viral penetration into host cells through ACE2 receptors, induction of inflammosomes and immune response through viral proteins, and the initiation of system-wide inflammation and cytokine production. Moreover, peripheral organ damage and underlying comorbid diseases which can lead to short term and long term, reversible and irreversible damage to the body have also been studied. We concluded that underlying comorbidities and their pathological effects on the body contributed immensely and determine the resultant disease severity and mortality of the patients. Presently there is no drug approved for treatment of COVID-19, however multiple vaccines are now in use and research for more is underway.

Type-2 Diabetes as a Risk Factor for Severe COVID-19 Infection

The current outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), termed coronavirus disease 2019 (COVID-19), has generated a notable challenge for diabetic patients. Overall, people with diabetes have a higher risk of developing different infectious diseases and demonstrate increased mortality. Type 2 diabetes mellitus (T2DM) is a significant risk factor for COVID-19 progression and its severity, poor prognosis, and increased mortality. How diabetes contributes to COVID-19 severity is unclear; however, it may be correlated with the effects of hyperglycemia on systemic inflammatory responses and immune system dysfunction. Using the envelope spike glycoprotein SARS-CoV-2, COVID-19 binds to angiotensin-converting enzyme 2 (ACE2) receptors, a key protein expressed in metabolic organs and tissues such as pancreatic islets. Therefore, it has been suggested that diabetic patients are more susceptible to severe SARS-CoV-2 infections, as glucose metabolism impairments complicate the pathophysiology of COVID-19 disease in these patients. In this review, we provide insight into the COVID-19 disease complications relevant to diabetes and try to focus on the present data and growing concepts surrounding SARS-CoV-2 infections in T2DM patients.

COVID-19 in Patients with Hypertension

Hypertension has been listed in several case series and retrospective cohorts as a potential risk factor for the incidence and severity of the new coronavirus (SARS-CoV-2)-associated disease (COVID-19). The debate is noteworthy because almost one billion people around the globe are estimated to have hypertensive diseases, according to the Global Burden of Disease study. Considering the SARS-CoV-2's high infectivity rates, a possible interaction between COVID-19 and hypertension is worrisome. Additionally, antihypertensive drugs, especially the renin-angiotensin-aldosterone system (RAAS) inhibitors, could also influence the natural course of COVID-19 infection. Not only can these associations hold from an epidemiologic standpoint, a mechanistic scenario possibly exists. Hypertension and antihypertensive drugs can increase the expression of transmembrane angiotensin-converting enzyme (ACE)-2 receptors, the entry target of the viruses, thus facilitating infectivity. On the other hand, an increase in ACE-2 could be protective considering the anti-inflammatory, antithrombotic effects of the ACE-2-angiotensin 1-7/Mas pathway. So far, little is known about the whole picture. Observational studies appear to indicate at least a twofold increased risk of mortality for hypertensive patients with COVID-19; however, the previous and continued use of RAAS inhibitors may be protective in this subgroup of patients. The scarcity of randomized clinical trials precludes evidence-based decision-making. At least one randomized study in a non-specified sub-analysis demonstrated no relationship between an angiotensin-converting enzyme inhibitor and incidence or severity of the disease. It is reflected mainly by observational studies and, therefore, by international cardiology societies' guidelines, which state that antihypertensive drugs, particularly RAAS inhibitors, should not be discontinued unless necessary on a case-by-case basis.

Soluble Angiotensin-Converting Enzyme 2, Cardiac Biomarkers, Structure, and Function, and Cardiovascular Events (from the Atherosclerosis Risk in Communities Study)

Membrane-bound angiotensin-converting enzyme 2 is important in regulation of the renin-angiotensin-aldosterone system, but the association of cleaved soluble ACE2 (sACE2) with cardiovascular disease (CVD) is unclear. We evaluated the association of sACE2 with cardiac biomarkers, structure, and function and cardiovascular events in the Atherosclerosis Risk in Communities Study. sACE2 was measured in a subset of 497 participants (mean age 78±5.4 years, 53% men, 27% black); Cox regression analyses assessed prospective associations of sACE2 with time to first CVD event at median 6.1-year follow-up. sACE2 was higher in men, blacks, and participants with prevalent CVD, diabetes, or hypertension. Higher sACE2 levels were associated with significantly higher biomarkers of cardiac injury (high-sensitivity cardiac troponin I and T, N-terminal pro-B-type natriuretic peptide), greater left ventricular mass index, and impaired diastolic function in linear regression analyses, and with increased risk for heart failure hospitalization (adjusted hazard ratio per natural log unit increase [HR] 1.32, 95% confidence interval [CI] 1.10 to 1.58), CVD events (HR 1.34, 95% CI 1.13 to 1.60), and all-cause death (HR 1.26, 95% CI 1.01 to 1.57). In an elderly biracial cohort, sACE2 was positively associated with biomarkers reflecting myocardial injury and neurohormonal activation, left ventricular mass index, impaired diastolic function, CVD, events and all-cause death.

Role of Inflammatory Cytokines in COVID-19 Patients: A Review on Molecular Mechanisms, Immune Functions, Immunopathology and Immunomodulatory Drugs to Counter Cytokine Storm

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a severe pandemic of the current century. The vicious tentacles of the disease have been disseminated worldwide with unknown complications and repercussions. Advanced COVID-19 syndrome is characterized by the uncontrolled and elevated release of pro-inflammatory cytokines and suppressed immunity, leading to the cytokine storm. The uncontrolled and dysregulated secretion of inflammatory and pro-inflammatory cytokines is positively associated with the severity of the viral infection and mortality rate. The secretion of various pro-inflammatory cytokines such as TNF-α, IL-1, and IL-6 leads to a hyperinflammatory response by recruiting macrophages, T and B cells in the lung alveolar cells. Moreover, it has been hypothesized that immune cells such as macrophages recruit inflammatory monocytes in the alveolar cells and allow the production of large amounts of cytokines in the alveoli, leading to a hyperinflammatory response in severely ill patients with COVID-19. This cascade of events may lead to multiple organ failure, acute respiratory distress, or pneumonia. Although the disease has a higher survival rate than other chronic diseases, the incidence of complications in the geriatric population are considerably high, with more systemic complications. This review sheds light on the pivotal roles played by various inflammatory markers in COVID-19-related complications. Different molecular pathways, such as the activation of JAK and JAK/STAT signaling are crucial in the progression of cytokine storm; hence, various mechanisms, immunological pathways, and functions of cytokines and other inflammatory markers have been discussed. A thorough understanding of cytokines' molecular pathways and their activation procedures will add more insight into understanding immunopathology and designing appropriate drugs, therapies, and control measures to counter COVID-19. Recently, anti-inflammatory drugs and several antiviral drugs have been reported as effective therapeutic drug candidates to control hypercytokinemia or cytokine storm. Hence, the present review also discussed prospective anti-inflammatory and relevant immunomodulatory drugs currently in various trial phases and their possible implications.

Dysregulation of the Renin-Angiotensin-Aldosterone System (RAA) in Patients Infected with SARS-CoV-2-Possible Clinical Consequences

SARS-CoV-2 impairs the renin-angiotensin-aledosterone system via binding ACE2 enzyme. ACE2 plays a key role in the biosynthesis of angiotensin (1-7), catalyzing the conversion of angiotensin 2 into angiotensin (1-7) and the reaction of angiotensin synthesis (1-9), from which angiotensin is (1-7) produced under the influence of ACE (Angiotensin-Converting Enzyme). Angiotensin 2 is a potent vasoconstrictor and atherogenic molecule converted by ACE2 to reducing inflammation and vasodilating in action angiotensin (1-7). Angiotensin (1-9), that is a product of angiotensin 1 metabolism and precursor of angiotensin (1-7), also exerts cell protective properties. Balance between angiotensin 2 and angiotensin (1-7) regulates blood pressure and ACE2 plays a critical role in this balance. ACE2, unlike ACE, is not inhibited by ACE inhibitors at the doses used in humans during the treatment of arterial hypertension. Membrane ACE2 is one of the receptors that allows SARS-CoV-2 to enter the host cells. ACE2 after SARS-CoV-2 binding is internalized and degraded. Hence ACE2 activity on the cell surface is reduced leading to increase the concentration of angiotensin 2 and decrease the concentration of angiotensin (1-7). Disturbed angiotensins metabolism, changes in ratio between angiotensins with distinct biological activities leading to domination of atherogenic angiotensin 2 can increase the damage to the lungs.

Risk of SARS-CoV-2 infection and COVID-19 prognosis with the use of renin-angiotensin-aldosterone system (RAAS) inhibitors: a systematic review

BACKGROUND

Angiotensin-converting-enzyme-2, being the receptor for SARS-CoV-2, is increased in the use of RAAS inhibitors. Therefore, concerns have been raised over risks of SARS-CoV-2 infection and poor prognosis of COVID-19 in persons with prior exposure to these drugs. This study aimed to systematically review available evidence for associations between exposure to RAAS inhibitors with susceptibility to SARS-CoV-2 infection and clinical outcomes in infected persons. It hopes to address the question on the effects of RAAS inhibitors on the risk of COVID-19 and its prognosis.

MAIN BODY

Search was conducted in the databases of PubMed, Scopus, Cochrane, Embase and MedRxiv.org from December 2019 to May 31, 2020, using relevant keywords. Additional articles were identified through hand-searching of reference lists. Studies that reported associations between positive tests to COVID-19 and use of RAAS inhibitors, and treatment outcomes of COVID-19 patients who had exposure to RAAS inhibitors were considered eligible. The Newcastle-Ottawa scale was used to assess risk of bias in individual studies. The review was conducted in line with Preferred Regulatory Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines 2009. From the 952 studies screened and 2 studies from reference hand-searching, 18 were reviewed. Four studies evaluated the risks for SARS-CoV-2 infection among RAAS inhibitors users, and 16 (including 2 of the 4 studies) evaluated the clinical outcomes associated with previous exposure to RAAS inhibitors.

CONCLUSION

Evidence does not suggest higher risks for SARS-CoV-2 infection or poor disease prognosis in the use of RAAS inhibitors. This suggests the continued use of RAAS inhibitors by patients with existing needs, which supports the position statements of American Heart Association and European societies for Cardiology.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s43094-021-00224-4.

Renal Manifestations of Covid-19: Physiology and Pathophysiology

Corona virus disease 2019 (COVID-19) imposes a serious public health pandemic affecting the whole world, as it is spreading exponentially. Besides its high infectivity, SARS-CoV-2 causes multiple serious derangements, where the most prominent is severe acute respiratory syndrome as well as multiple organ dysfunction including heart and kidney injury. While the deleterious impact of SARS-CoV-2 on pulmonary and cardiac systems have attracted remarkable attention, the adverse effects of this virus on the renal system is still underestimated. Kidney susceptibility to SARS-CoV-2 infection is determined by the presence of angiotensin-converting enzyme 2 (ACE2) receptor which is used as port of the viral entry into targeted cells, tissue tropism, pathogenicity and subsequent viral replication. The SARS-CoV-2 cellular entry receptor, ACE2, is widely expressed in proximal epithelial cells, vascular endothelial and smooth muscle cells and podocytes, where it supports kidney integrity and function via the enzymatic production of Angiotensin 1-7 (Ang 1-7), which exerts vasodilatory, anti-inflammatory, antifibrotic and diuretic/natriuretic actions via activation of the Mas receptor axis. Loss of this activity constitutes the potential basis for the renal damage that occurs in COVID-19 patients. Indeed, several studies in a small sample of COVID-19 patients revealed relatively high incidence of acute kidney injury (AKI) among them. Although SARS-CoV-1 -induced AKI was attributed to multiorgan failure and cytokine release syndrome, as the virus was not detectable in the renal tissue of infected patients, SARS-CoV-2 antigens were detected in kidney tubules, suggesting that SARS-CoV-2 infects the human kidney directly, and eventually induces AKI characterized with high morbidity and mortality. The mechanisms underlying this phenomenon are largely unknown. However, the fact that ACE2 plays a crucial role against renal injury, the deprivation of the kidney of this advantageous enzyme, along with local viral replication, probably plays a central role. The current review focuses on the critical role of ACE2 in renal physiology, its involvement in the development of kidney injury during SARS-CoV-2 infection, renal manifestations and therapeutic options. The latter includes exogenous administration of Ang (1-7) as an appealing option, given the high incidence of AKI in this ACE2-depleted disorder, and the benefits of ACE2/Ang1-7 including vasodilation, diuresis, natriuresis, attenuation of inflammation, oxidative stress, cell proliferation, apoptosis and coagulation.

Identification and Development of Therapeutics for COVID-19

After emerging in China in late 2019, the novel coronavirus SARS-CoV-2 spread worldwide and as of mid-2021 remains a significant threat globally. Only a few coronaviruses are known to infect humans, and only two cause infections similar in severity to SARS-CoV-2: Severe acute respiratory syndrome-related coronavirus, a closely related species of SARS-CoV-2 that emerged in 2002, and Middle East respiratory syndrome-related coronavirus, which emerged in 2012. Unlike the current pandemic, previous epidemics were controlled rapidly through public health measures, but the body of research investigating severe acute respiratory syndrome and Middle East respiratory syndrome has proven valuable for identifying approaches to treating and preventing novel coronavirus disease 2019 (COVID-19). Building on this research, the medical and scientific communities have responded rapidly to the COVID-19 crisis to identify many candidate therapeutics. The approaches used to identify candidates fall into four main categories: adaptation of clinical approaches to diseases with related pathologies, adaptation based on virological properties, adaptation based on host response, and data-driven identification of candidates based on physical properties or on pharmacological compendia. To date, a small number of therapeutics have already been authorized by regulatory agencies such as the Food and Drug Administration (FDA), while most remain under investigation. The scale of the COVID-19 crisis offers a rare opportunity to collect data on the effects of candidate therapeutics. This information provides insight not only into the management of coronavirus diseases, but also into the relative success of different approaches to identifying candidate therapeutics against an emerging disease.

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

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

Upregulation of the Renin-Angiotensin System Pathways and SARS-CoV-2 Infection: The Rationale for the Administration of Zinc-Chelating Agents in COVID-19 Patients

The article describes the rationale for the administration of zinc-chelating agents in COVID-19 patients. In a previous work I have highlighted that the binding of the SARS-CoV spike proteins to the zinc-metalloprotease ACE2 has been shown to induce ACE2 shedding by activating the zinc-metalloprotease ADAM17, which ultimately leads to systemic upregulation of ACE2 activity. Moreover, based on experimental models, it was also shown the detrimental effect of the excessive systemic activity of ACE2 through its downstream pathways, which leads to "clinical" manifestations resembling COVID-19. In this regard, strong upregulation of circulating ACE2 activity was recently reported in COVID-19 patients, thus supporting the previous hypothesis that COVID-19 may derive from upregulation of ACE2 activity. Based on this, a reasonable hypothesis of using inhibitors that curb the upregulation of both ACE2 and ADAM17 zinc-metalloprotease activities and consequent positive feedback-loops (initially triggered by SARS-CoV-2 and subsequently sustained independently on viral trigger) is proposed as therapy for COVID-19. In particular, zinc-chelating agents such as citrate and ethylenediaminetetraacetic acid (EDTA) alone or in combination are expected to act in protecting from COVID-19 at different levels thanks to their both anticoagulant properties and inhibitory activity on zinc-metalloproteases. Several arguments are presented in support of this hypothesis and based on the current knowledge of both beneficial/harmful effects and cost/effectiveness, the use of chelating agents in the prevention and therapy of COVID-19 is proposed. In this regard, clinical trials (currently absent) employing citrate/EDTA in COVID-19 are urgently needed in order to shed more light on the efficacy of zinc chelators against SARS-CoV-2 infection in vivo.

Controversial Roles of the Renin Angiotensin System and Its Modulators During the COVID-19 Pandemic

Since December 2019, the coronavirus 2019 (COVID-19) pandemic has rapidly spread and overwhelmed healthcare systems worldwide, urging physicians to understand how to manage this novel infection. Early in the pandemic, more severe forms of COVID-19 have been observed in patients with cardiovascular comorbidities, who are often treated with renin-angiotensin aldosterone system (RAAS)-blockers, such as angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs), but whether these are indeed independent risk factors is unknown. The cellular receptor for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the membrane-bound angiotensin converting enzyme 2 (ACE2), as for SARS-CoV(-1). Experimental data suggest that expression of ACE2 may be increased by RAAS-blockers, raising concerns that these drugs may facilitate viral cell entry. On the other hand, ACE2 is a key counter-regulator of the RAAS, by degrading angiotensin II into angiotensin (1-7), and may thereby mediate beneficial effects in COVID-19. These considerations have raised concerns about the management of these drugs, and early comments shed vivid controversy among physicians. This review will describe the homeostatic balance between ACE-angiotensin II and ACE2-angiotensin (1-7) and summarize the pathophysiological rationale underlying the debated role of the RAAS and its modulators in the context of the pandemic. In addition, we will review available evidence investigating the impact of RAAS blockers on the course and prognosis of COVID-19 and discuss why retrospective observational studies should be interpreted with caution. These considerations highlight the importance of solid evidence-based data in order to guide physicians in the management of RAAS-interfering drugs in the general population as well as in patients with more or less severe forms of SARS-CoV-2 infection.

An Open Label Trial to Assess Safety of Losartan for Treating Worsening Respiratory Illness in COVID-19

Rationale: Coronavirus disease 2019 (COVID-19) can cause disruption of the renin-angiotensin system in the lungs, possibly contributing to pulmonary capillary leakage. Thus, angiotensin receptor blockers (ARBs) may improve respiratory failure. Objective: Assess safety of losartan for use in respiratory failure related to COVID-19 (NCT04335123). Methods: Single arm, open label trial of losartan in those hospitalized with respiratory failure related to COVID-19. Oral losartan (25 mg daily for 3 days, then 50 mg) was administered from enrollment until day 14 or hospital discharge. A post-hoc external control group with patients who met all inclusion criteria was matched 1:1 to the treatment group using propensity scores for comparison. Measures: Primary outcome was cumulative incidence of any adverse events. Secondary, explorative endpoints included measures of respiratory failure, length of stay and vital status. Results: Of the 34 participants enrolled in the trial, 30 completed the study with a mean age SD of 53.8 ± 17.7 years and 17 males (57%). On losartan, 24/30 (80%) experienced an adverse event as opposed to 29/30 (97%) of controls, with a lower average number of adverse events on losartan relative to control (2.2 vs. 3.3). Using Poisson regression and controlling for age, sex, race, date of enrollment, disease severity at enrollment, and history of high-risk comorbidities, the incidence rate ratio of adverse events on losartan relative to control was 0.69 (95% CI: 0.49-0.97) Conclusions: Losartan appeared safe for COVID-19-related acute respiratory compromise. To assess true efficacy, randomized trials are needed.

Understanding Viral Infection Mechanisms and Patient Symptoms for the Development of COVID-19 Therapeutics

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 virus, has become a worldwide pandemic. Symptoms range from mild fever to cough, fatigue, severe pneumonia, acute respiratory distress syndrome (ARDS), and organ failure, with a mortality rate of 2.2%. However, there are no licensed drugs or definitive treatment strategies for patients with severe COVID-19. Only antiviral or anti-inflammatory drugs are used as symptomatic treatments based on clinician experience. Basic medical researchers are also trying to develop COVID-19 therapeutics. However, there is limited systematic information about the pathogenesis of COVID-19 symptoms that cause tissue damage or death and the mechanisms by which the virus infects and replicates in cells. Here, we introduce recent knowledge of time course changes in viral titers, delayed virus clearance, and persistent systemic inflammation in patients with severe COVID-19. Based on the concept of drug reposition, we review which antiviral or anti-inflammatory drugs can effectively treat COVID-19 patients based on progressive symptoms and the mechanisms inhibiting virus infection and replication.

Renin-angiotensin system blockade in the COVID-19 pandemic

In the early months of the coronavirus disease 2019 (COVID-19) pandemic, a hypothesis emerged suggesting that pharmacologic inhibitors of the renin–angiotensin system (RAS) may increase COVID-19 severity. This hypothesis was based on the role of angiotensin-converting enzyme 2 (ACE2), a counterregulatory component of the RAS, as the binding site for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), allowing viral entry into host cells. Extrapolations from prior evidence led to speculation that upregulation of ACE2 by RAS blockade may increase the risk of adverse outcomes from COVID-19. However, counterarguments pointed to evidence of potential protective effects of ACE2 and RAS blockade with regard to acute lung injury, as well as substantial risks from discontinuing these commonly used and important medications. Here we provide an overview of classic RAS physiology and the crucial role of ACE2 in systemic pathways affected by COVID-19. Additionally, we critically review the physiologic and epidemiologic evidence surrounding the interactions between RAS blockade and COVID-19. We review recently published trial evidence and propose important future directions to improve upon our understanding of these relationships.

The role of SARS-CoV-2 target ACE2 in cardiovascular diseases

SARS-CoV-2, the virus responsible for the global coronavirus disease (COVID-19) pandemic, attacks multiple organs of the human body by binding to angiotensin-converting enzyme 2 (ACE2) to enter cells. More than 20 million people have already been infected by the virus. ACE2 is not only a functional receptor of COVID-19 but also an important endogenous antagonist of the renin-angiotensin system (RAS). A large number of studies have shown that ACE2 can reverse myocardial injury in various cardiovascular diseases (CVDs) as well as is exert anti-inflammatory, antioxidant, anti-apoptotic and anticardiomyocyte fibrosis effects by regulating transforming growth factor beta, mitogen-activated protein kinases, calcium ions in cells and other major pathways. The ACE2/angiotensin-(1-7)/Mas receptor axis plays a decisive role in the cardiovascular system to combat the negative effects of the ACE/angiotensin II/angiotensin II type 1 receptor axis. However, the underlying mechanism of ACE2 in cardiac protection remains unclear. Some approaches for enhancing ACE2 expression in CVDs have been suggested, which may provide targets for the development of novel clinical therapies. In this review, we aimed to identify and summarize the role of ACE2 in CVDs.

ACE2/Ang-(1-7)/Mas1 axis and the vascular system: vasoprotection to COVID-19-associated vascular disease

The two axes of the renin-angiotensin system include the classical ACE/Ang II/AT1 axis and the counter-regulatory ACE2/Ang-(1-7)/Mas1 axis. ACE2 is a multifunctional monocarboxypeptidase responsible for generating Ang-(1-7) from Ang II. ACE2 is important in the vascular system where it is found in arterial and venous endothelial cells and arterial smooth muscle cells in many vascular beds. Among the best characterized functions of ACE2 is its role in regulating vascular tone. ACE2 through its effector peptide Ang-(1-7) and receptor Mas1 induces vasodilation and attenuates Ang II-induced vasoconstriction. In endothelial cells activation of the ACE2/Ang-(1-7)/Mas1 axis increases production of the vasodilator's nitric oxide and prostacyclin's and in vascular smooth muscle cells it inhibits pro-contractile and pro-inflammatory signaling. Endothelial ACE2 is cleaved by proteases, shed into the circulation and measured as soluble ACE2. Plasma ACE2 activity is increased in cardiovascular disease and may have prognostic significance in disease severity. In addition to its enzymatic function, ACE2 is the receptor for severe acute respiratory syndrome (SARS)-coronavirus (CoV) and SARS-Cov-2, which cause SARS and coronavirus disease-19 (COVID-19) respectively. ACE-2 is thus a double-edged sword: it promotes cardiovascular health while also facilitating the devastations caused by coronaviruses. COVID-19 is associated with cardiovascular disease as a risk factor and as a complication. Mechanisms linking COVID-19 and cardiovascular disease are unclear, but vascular ACE2 may be important. This review focuses on the vascular biology and (patho)physiology of ACE2 in cardiovascular health and disease and briefly discusses the role of vascular ACE2 as a potential mediator of vascular injury in COVID-19.

Angiotensin converting enzymes inhibitors or angiotensin receptor blockers should be continued in COVID-19 patients with hypertension

BACKGROUND

Recent studies have revealed that sustained ingestion of angiotensin converting enzymes inhibitors or angiotensin receptor blockers (ACEIs/ARBs) had no harmful effects on coronavirus disease 2019 (COVID-19) patients complicated with hypertension.

AIM

To investigate the impact on COVID-19 patients complicated with hypertension who discontinued using ACEIs/ARBs.

METHODS

All COVID-19 patients complicated with hypertension admitted to our isolated unit were consecutively recruited in this study. Some patients switched from ACEIs/ARBs to calcium channel blocker (CCBs) after admission, while others continued using non-ACEIs/ARBs. We compared characteristics and clinical outcomes between these two groups of patients.

RESULTS

A total of 53 patients were enrolled, 27 patients switched from ACEIs/ARBs to CCBs while 26 patients continued with non-ACEIs/ARBs. After controlling potential confounding factors using the Cox proportional hazards model, hospital stay was longer in patients who discontinued ACEIs/ARBs, with a hazard ratio of 0.424 (95% confidence interval: 0.187-0.962; P = 0.040), upon discharge than patients using other anti-hypertensive drugs. A sub-group analysis showed that the effect of discontinuing use of ACEIs/ARBs was stronger in moderate cases [hazard ratio = 0.224 (95% confidence interval: 0.005-0.998; P = 0.0497)].

CONCLUSION

Patients in the discontinued ACEIs/ARBs group had longer hospital stays. Our findings suggest that COVID-19 patients complicated with hypertension should continue to use ACEIs/ARBs.

The soluble catalytic ectodomain of ACE2 a biomarker of cardiac remodelling: new insights for heart failure and COVID19

The angiotensin-converting enzyme 2 (ACE2) is a type I integral membrane that was discovered two decades ago. The ACE2 exists as a transmembrane protein and as a soluble catalytic ectodomain of ACE2, also known as the soluble ACE2 that can be found in plasma and other body fluids. ACE2 regulates the local actions of the renin-angiotensin system in cardiovascular tissues, and the ACE2/Angiotensin 1–7 axis exerts protective actions in cardiovascular disease. Increasing soluble ACE2 has been associated with heart failure, cardiovascular disease, and cardiac remodelling. This is a review of the molecular structure and biochemical functions of the ACE2, as well we provided an updated on the evidence, clinical applications, and emerging potential therapies with the ACE2 in heart failure, cardiovascular disease, lung injury, and COVID-19 infection.

Renin-Angiotensin-Aldosterone System (RAAS) Inhibitors and Coronavirus Disease 2019 (COVID-19)

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the virus responsible for the coronavirus disease 2019 (COVID-19) pandemic. The angiotensin-converting enzyme 2 (ACE2) has been proven to be used by SARS-CoV-2 for host cell entry. Considering that angiotensin receptor blockers and ACE inhibitors (ACEIs) upregulate the expression of ACE2 in animal studies, there may be a concern about whether these drugs may increase COVID-19 susceptibility and severity. Recently, there has been a debate among clinicians about whether to continue or to stop ACEIs and angiotensin receptor blockers in the context of COVID-19. Also, some media outlets and health systems have called for the discontinuation of these drugs in the context of suspected COVID-19. This has necessitated an urgent release of guidance on the use of such medications in COVID-19 patients. To date, multiple theories relating to the pure effects of renin-angiotensin-aldosterone system (RAAS) inhibitors on COVID-19 infections have been postulated. Favorable effects include blocking the ACE2 receptors, preventing viral entry into the heart and lungs, and protecting against lung injury in COVID-19. Adverse effects include a possible retrograde feedback mechanism that upregulates ACE2 receptors. This review provides greater insight into the role of the RAAS axis in acute lung injury and the effects of RAAS inhibitors on SARS-CoVs. The hypothesis that RAAS inhibitors facilitate viral insertion and the alternative hypothesis of the beneficial role of these drugs are discussed. Up-to-date published data concerning the RAAS inhibitors and COVID-19 are summarized.

ACE2: the molecular doorway to SARS-CoV-2

The angiotensin-converting enzyme 2 (ACE2) is the host functional receptor for the new virus SARS-CoV-2 causing Coronavirus Disease 2019. ACE2 is expressed in 72 different cell types. Some factors that can affect the expression of the ACE2 are: sex, environment, comorbidities, medications (e.g. anti-hypertensives) and its interaction with other genes of the renin-angiotensin system and other pathways. Different factors can affect the risk of infection of SARS-CoV-2 and determine the severity of the symptoms. The ACE2 enzyme is a negative regulator of RAS expressed in various organ systems. It is with immunity, inflammation, increased coagulopathy, and cardiovascular disease. In this review, we describe the genetic and molecular functions of the ACE2 receptor and its relation with the physiological and pathological conditions to better understand how this receptor is involved in the pathogenesis of COVID-19. In addition, it reviews the different comorbidities that interact with SARS-CoV-2 in which also ACE2 plays an important role. It also describes the different factors that interact with the virus that have an influence in the expression and functional activities of the receptor. The goal is to provide the reader with an understanding of the complexity and importance of this receptor.

Hypertension and renin-angiotensin system blockers are not associated with expression of angiotensin-converting enzyme 2 (ACE2) in the kidney

AIMS

Angiotensin-converting enzyme 2 (ACE2) is the cellular entry point for severe acute respiratory syndrome coronavirus (SARS-CoV-2)-the cause of coronavirus disease 2019 (COVID-19). However, the effect of renin-angiotensin system (RAS)-inhibition on ACE2 expression in human tissues of key relevance to blood pressure regulation and COVID-19 infection has not previously been reported.

METHODS AND RESULTS

We examined how hypertension, its major metabolic co-phenotypes, and antihypertensive medications relate to ACE2 renal expression using information from up to 436 patients whose kidney transcriptomes were characterized by RNA-sequencing. We further validated some of the key observations in other human tissues and/or a controlled experimental model. Our data reveal increasing expression of ACE2 with age in both human lungs and the kidney. We show no association between renal expression of ACE2 and either hypertension or common types of RAS inhibiting drugs. We demonstrate that renal abundance of ACE2 is positively associated with a biochemical index of kidney function and show a strong enrichment for genes responsible for kidney health and disease in ACE2 co-expression analysis.

CONCLUSION

Our results indicate that neither hypertension nor antihypertensive treatment is likely to alter the expression of the key entry receptor for SARS-CoV-2 in the human kidney. Our data further suggest that in the absence of SARS-CoV-2 infection, kidney ACE2 is most likely nephro-protective but the age-related increase in its expression within lungs and kidneys may be relevant to the risk of SARS-CoV-2 infection.

ACE2, angiotensin 1-7 and skeletal muscle: review in the era of COVID-19

Angiotensin converting enzyme-2 (ACE2) is a multifunctional transmembrane protein recently recognised as the entry receptor of the virus causing COVID-19. In the renin–angiotensin system (RAS), ACE2 cleaves angiotensin II (Ang II) into angiotensin 1-7 (Ang 1-7), which is considered to exert cellular responses to counteract the activation of the RAS primarily through a receptor, Mas, in multiple organs including skeletal muscle. Previous studies have provided abundant evidence suggesting that Ang 1-7 modulates multiple signalling pathways leading to protection from pathological muscle remodelling and muscle insulin resistance. In contrast, there is relatively little evidence to support the protective role of ACE2 in skeletal muscle. The potential contribution of endogenous ACE2 to the regulation of Ang 1-7-mediated protection of these muscle pathologies is discussed in this review. Recent studies have suggested that ACE2 protects against ageing-associated muscle wasting (sarcopenia) through its function to modulate molecules outside of the RAS. Thus, the potential association of sarcopenia with ACE2 and the associated molecules outside of RAS is also presented herein. Further, we introduce the transcriptional regulation of muscle ACE2 by drugs or exercise, and briefly discuss the potential role of ACE2 in the development of COVID-19.

Cardiovascular Manifestations and Mechanisms in Patients with COVID-19

Coronavirus disease 2019 (COVID-19) patients with pre-existing cardiovascular disease (CVD) or with cardiovascular complications have a higher risk of mortality. The main cardiovascular complications of COVID-19 include acute cardiac injury, acute myocardial infarction (AMI), myocarditis, arrhythmia, heart failure, shock, and venous thromboembolism (VTE)/pulmonary embolism (PE). COVID-19 can cause cardiovascular complications or deterioration of coexisting CVD through direct or indirect mechanisms, including viral toxicity, dysregulation of the renin-angiotensin-aldosterone system (RAAS), endothelial cell damage and thromboinflammation, cytokine storm, and oxygen supply-demand mismatch. We systematically review cardiovascular manifestations, histopathology, and mechanisms of COVID-19, to help to formulate future research goals and facilitate the development of therapeutic management strategies.

Coronavirus Disease 2019 (COVID-19) and its implications for cardiovascular care: expert document from the German Cardiac Society and the World Heart Federation

Coronavirus diseases 2019 (COVID-19) has become a worldwide pandemic affecting people at high risk and particularly at advanced age, cardiovascular and pulmonary disease. As cardiovascular patients are at high risk but also have dyspnea and fatigue as leading symptoms, prevention, diagnostics and treatment in these patients are important to provide adequate care for those with or without COVID-19 but most importantly when comorbid cardiovascular conditions are present. Severe COVID-19 with acute respiratory distress (ARDS) is challenging as patients with elevated myocardial markers such as troponin are at enhanced high risk for fatal outcomes. As angiotensin-converting enzyme 2 (ACE2) is regarded as the viral receptor for cell entry and as the Coronavirus is downregulating this enzyme, which provides cardiovascular and pulmonary protection, there is ongoing discussions on whether treatment with cardiovascular drugs, which upregulate the viral receptor ACE2 should be modified. As most of the COVID-19 patients have cardiovascular comorbidities like hypertension, diabetes, coronary artery disease and heart failure, which imposes a high risk on these patients, cardiovascular therapy should not be modified or even withdrawn. As cardiac injury is a common feature of COVID-19 associated ARDS and is linked with poor outcomes, swift diagnostic management and specialist care of cardiovascular patients in the area of COVID-19 is of particular importance and deserves special attention.

Mortality and Disease Severity Among COVID-19 Patients Receiving Renin-Angiotensin System Inhibitors: A Systematic Review and Meta-analysis

INTRODUCTION

The use of renin-angiotensin system (RAS) inhibitors, including angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), was alleged to cause a more severe course of novel coronavirus disease 2019 (COVID-19).

METHODS

We systematically reviewed the published studies to assess the association of RAS inhibitors with mortality as well as disease severity in COVID-19 patients. A systematic literature search was performed to retrieve relevant original studies investigating mortality and severity (severe/critical disease) in COVID-19 patients with and without exposure to RAS inhibitors.

RESULTS

A total of 59 original studies were included for qualitative synthesis. Twenty-four studies that reported adjusted effect sizes (24 studies reported mortality outcomes and 16 studies reported disease severity outcomes), conducted in RAS inhibitor-exposed and unexposed groups, were pooled in random-effects models to estimate overall risk. Quality assessment of studies revealed that most of the studies included were of fair quality. The use of an ACEI/ARB in COVID-19 patients was significantly associated with lower odds (odds ratio [OR] = 0.73, 95% confidence interval [CI] 0.56-0.95; n = 18,749) or hazard (hazard ratio [HR] = 0.75, 95% CI 0.60-0.95; n = 26,598) of mortality compared with non-use of ACEI/ARB. However, the use of an ACEI/ARB was non-significantly associated with lower odds (OR = 0.91, 95% CI 0.75-1.10; n = 7446) or hazard (HR = 0.73, 95% CI 0.33-1.66; n = 6325) of developing severe/critical disease compared with non-use of an ACEI/ARB.

DISCUSSION

Since there was no increased risk of harm, the use of RAS inhibitors for hypertension and other established clinical indications can be maintained in COVID-19 patients.

Renin-angiotensin system inhibition and risk of infection and mortality in COVID-19: a systematic review and meta-analysis

Background

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the causative agent of COVID‐19, enters human cells by binding of its viral protein to the aminopeptidase angiotensin‐converting enzyme 2 (ACE2). This has led to speculation whether treatment with renin–angiotensin system (RAS) inhibitors was associated with an increased likelihood of a positive test for COVID‐19 and risk of mortality.

Aims

We performed a systematic review and meta‐analysis to investigate whether RAS inhibitors increased the likelihood of a positive test or death/severe illness in patients with COVID‐19.

Methods

A systematic search of MEDLINE, PubMed and EMBASE was conducted for studies stratified by the use of angiotensin‐converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB). Pooled analysis was performed using a random‐effects model.

Results

Seven trials of 73 122 patients were included. Overall, 16 624 (22.7%) patients had a positive COVID‐19 test and 7892 (10.8%) were on a RAS inhibitor. RAS inhibitors were not associated with higher likelihood of a positive COVID‐19 test result (odds ratio (OR) 0.97 (95% CI 0.97–1.05, P = 0.48) with low heterogeneity. This was comparable when stratifying by use of each medication class. The use of RAS inhibitors was also not associated with mortality or severe illness (OR 0.89, 95% CI 0.73–1.07, P = 0.21) with moderate heterogeneity.

Conclusion

Use of ACEI or ARB was not associated with a heightened susceptibility for a positive diagnosis of COVID‐19. Furthermore, they were not associated with increased illness severity or mortality due to COVID‐19. Randomised controlled trials are needed to address definitively the potential benefits or harms of RAS inhibitors in patients with COVID‐19.

COVID-19 and cardiovascular diseases

Infection by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is responsible for the second pandemic of the XXI century after influenza A in 2009. As of mid-June 2020, more than 4,40,000 fatal cases of SARS-CoV-2-related disease (COVID-19) have occurred worldwide. Besides its prominent expression at the level of the respiratory apparatus, COVID-19 is also characterized by a substantial degree of cardiovascular involvement, both in terms of deterioration of pre-existing conditions, and as the effect of inflammation-facilitated acute events. They include ischemic/inflammatory heart disease, ventricular arrhythmias, conduction disturbances, thrombotic events at the level of the lungs, and systemic activation of the coagulation cascade, configuring the scenario of disseminated intravascular coagulation. Herein, we summarize the main COVID-19 features of relevance for the clinicians in the cardiovascular field. The rationale, concerns, and possible side effects of specific therapeutic measures, including anticoagulants, renin-angiotensin-aldosterone system inhibitors, and anti-inflammatory/antiviral medications applied to the treatment of COVID-19 are also discussed.