The Role of Endothelial Related Circulating Biomarkers in COVID-19. A Systematic Review and Meta-analysis

Midregional-proAdrenomedullin as a prognostic tool in sepsis and septic shock: A systematic review and meta-analysis

BACKGROUND

Midregional-proAdrenomedullin (MR-proADM) has been recently proposed as a tool in patients with sepsis and septic shock. Our aim was to evaluate the prognostic role of MR-proADM in hospitalized patients with sepsis and septic shock.

METHODS

PRISMA guideline was followed. MEDLINE and EMBASE were searched up to June 2023. Primary outcome was mean difference in MR-proADM among survivors and nonsurvivors, secondary outcome mean difference in MR-proADM according to infection severity and type. Risk of bias was evaluated using Newcastle-Ottawa scale for observational studies and Cochrane tool for randomized trials. Pooled mean differences (MD) with corresponding 95% confidence intervals (CIs) were calculated in a random-effects model.

RESULTS

Twenty-four studies included 6730 adult patients (1208 nonsurvivors and 5522 survivors) and three studies included 195 paediatric patients (30 nonsurvivors and 165 survivors). A total of 10, 4 and 13 studies included, respectively, patients with sepsis (3602 patients), septic shock (386 patients) and a mixed population (2937 patients). Twenty-one studies included patients with different source of infection, three with pneumonia and one with a catheter-related infection. Most studies (n = 12) had a follow-up of 28 days. In adult cohort, pooled mean difference between nonsurvivors and survivors of MR-proADM was 2.55 mmol/L (95% CI: 1.95-3.15) with higher values in patients with septic shock (4.25 mmol/L; 95% CI, 2.23-6.26 mmol/L) than in patients with sepsis (1.77 mmol/L; 95% CI: 1.11-2.44 mmol/L). In paediatric cohort, pooled mean difference was 3.11 mmol/L (95% CI: -0.02-6.24 mmol/L).

CONCLUSIONS

Higher values of MR-proADM are detectable in nonsurvivors adult and paediatric-hospitalized patients with sepsis or septic shock.

Sex differences in vascular endothelial function related to acute and long COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has been at the forefront of health sciences research since its emergence in China in 2019 that quickly led to a global pandemic. As a result of this research, and the large numbers of infected patients globally, there were rapid enhancements made in our understanding of Coronavirus disease 2019 (COVID-19) pathology, including its role in the development of uncontrolled immune responses and its link to the development of endotheliitis and endothelial dysfunction. There were also some noted differences in the rate and severity of infection between males and females with acute COVID. Some individuals infected with SARS-CoV-2 also experience long-COVID, an important hallmark symptom of this being Myalgic Encephalomyelitis-Chronic Fatigue Syndrome (ME-CFS), also experienced differently between males and females. The purpose of this review is to discuss the impact of sex on the vasculature during acute and long COVID-19, present any link between ME-CFS and endothelial dysfunction, and provide evidence for the relationship between ME-CFS and the immune system. We also will delineate biological sex differences observed in other post viral infections and, assess if sex differences exist in how the immune system responds to viral infection causing ME-CFS.

The role of proadrenomedullin, interleukin 6 and CD64 in the diagnosis and prognosis of septic shock

INTRODUCTION

Sepsis and septic shock are disorders of tissue perfusion and microcirculation associated with increased mortality. The role of biomarkers such as proadrenomedullin (PRO-ADM), interleukin 6 (IL-6) and neutrophil CD64 (CD64) in the diagnosis and prognosis of septic shock has been studied.

METHODS

GCS, SOFA score, APACHE 2 score, lactate, CRP, procalcitonin, PRO-ADM, IL-6, CD64 level and 28-day mortality were evaluated in patients with septic shock followed-up in the intensive care unit of Marmara University Hospital between July 2021 and December 2021. The study was planned as prospective, non-drug clinical research Committee.

RESULTS

There were no statistically significant differences between patient groups in gender, BMI, and presence of comorbidities (p > 0.05). The alive patient group had significantly higher GCS values and lower SOFA, APACHE 2, lactate and CD64 values than the dead patient group (p < 0.01). The cut-off values of laboratory parameters were determined using ROC analysis to predict mortality, SOFA and CD64 had high AUC. This is also a good indicator for mortality.The multivariate logistic regression model was estimated using the backward selection method. The mortality of ICU patients was predicted by a SOFA-value ≥ 12 (OR (95%CI) = 56.13 (5.44-578.64)), CD64 value ≥ 28.54 (OR (95% CI) = 23.78 (2.61-216.85)), and ADM-value ≥ 86.79 (OR (95% CI) = 15.86 (1.02-246.49)) (p < 0.05) .

CONCLUSION

In conclusion, serum CD64 level, PRO-ADM level, and SOFA score proved to be effective parameters for predicting prognosis and mortality in septic shock. However, IL-6 proved to be a weak biomarker and failed to predict mortality. CD64, which is easier and more practical to use, can be used instead of the SOFA score.

Predictors of mortality in critically ill patients with COVID-19 and diabetes

The COVID-19 pandemic has challenged the entire world, and patients with diabetes mellitus (DM) have been particularly affected. We aimed to evaluate predictors of mortality during the first 30 days of hospitalization in critically ill patients with COVID-19 and comorbid DM. This prospective study included 110 critically ill patients admitted with COVID-19 infection. Thirty-two (29%) patients had a previous diagnosis of DM. Clinical variables, laboratory tests, and vascular biomarkers, such as VCAM-1, syndecan-1, ICAM-1, angiopoietin-1, and angiopoeitin-2, were evaluated after intensive care unit (ICU) admission. A comparison was made between patients with and without DM. No difference in mortality was observed between the groups (48.7 vs 46.9%, P=0.861). In the multivariate Cox regression analysis, VCAM-1 levels at ICU admission (HR: 1 [1-1.001], P<0.006) were associated with death in patients with DM. Among patients with DM, advanced age (HR 1.063 [1.031-1.096], P<0.001), increased Ang-2/Ang-1 ratio (HR: 4.515 [1.803-11.308] P=0.001), and need for dialysis (HR: 3.489 [1.409-8.642], P=0.007) were independent predictors of death. Higher levels of VCAM-1 in patients with DM was better at predicting death of patients with severe COVID-19 and comorbid DM, and their cut-off values were useful for stratifying patients with a worse prognosis. Vascular biomarkers VCAM-1 and Ang-2/Ang-1 ratio were predictors of death in patients with severe COVID-19 and comorbid DM and those without DM. Additionally, kidney injury was associated with an increased risk of death.

Long-term hypercoagulability, endotheliopathy and inflammation following acute SARS-CoV-2 infection

INTRODUCTION

both symptomatic and asymptomatic SARS-CoV-2 infections - coined Coronavirus disease 2019 (COVID-19) - have been linked to a higher risk of cardiovascular events after recovery.

AREAS COVERED

our review aims to summarize the latest evidence on the increased thrombotic and cardiovascular risk in recovered COVID-19 patients and to examine the pathophysiological mechanisms underlying the interplay among endothelial dysfunction, inflammatory response and coagulation in long-COVID. We performed a systematic search of studies on hypercoagulability, endothelial dysfunction and inflammation after SARS-CoV-2 infection.

EXPERT OPINION

endothelial dysfunction is a major pathophysiological mechanism responsible for most clinical manifestations in COVID-19. The pathological activation of endothelial cells by a virus infection results in a pro-adhesive and chemokine-secreting phenotype, which in turn promotes the recruitment of circulating leukocytes. Cardiovascular events after COVID-19 appear to be related to persistent immune dysregulation. Patients with long-lasting symptoms display higher amounts of proinflammatory molecules such as tumor necrosis factor-α, interferon γ and interleukins 2 and 6. Immune dysregulation can trigger the activation of the coagulation pathway. The formation of extensive microclots in vivo, both during acute COVID-19 and in long-COVID-19, appears to be a relevant mechanism responsible for persistent symptoms and cardiovascular events.

Molecular Mechanisms and Therapeutic Implications of Endothelial Dysfunction in Patients with Heart Failure

Heart failure is a complex medical syndrome that is attributed to a number of risk factors; nevertheless, its clinical presentation is quite similar among the different etiologies. Heart failure displays a rapidly increasing prevalence due to the aging of the population and the success of medical treatment and devices. The pathophysiology of heart failure comprises several mechanisms, such as activation of neurohormonal systems, oxidative stress, dysfunctional calcium handling, impaired energy utilization, mitochondrial dysfunction, and inflammation, which are also implicated in the development of endothelial dysfunction. Heart failure with reduced ejection fraction is usually the result of myocardial loss, which progressively ends in myocardial remodeling. On the other hand, heart failure with preserved ejection fraction is common in patients with comorbidities such as diabetes mellitus, obesity, and hypertension, which trigger the creation of a micro-environment of chronic, ongoing inflammation. Interestingly, endothelial dysfunction of both peripheral vessels and coronary epicardial vessels and microcirculation is a common characteristic of both categories of heart failure and has been associated with worse cardiovascular outcomes. Indeed, exercise training and several heart failure drug categories display favorable effects against endothelial dysfunction apart from their established direct myocardial benefit.

Impaired left ventricular deformation and ventricular-arterial coupling in post-COVID-19: association with autonomic dysregulation

Coronavirus disease-19 (COVID-19) has extended implications namely the long COVID-19 syndrome. We assessed over-time changes in left ventricular (LV) function, aortic stiffness, autonomic function, and ventricular-arterial coupling (VAC) in post-COVID-19 patients. We followed 34 post-COVID-19 subjects, up to 6 months post-hospital discharge. Subjects without COVID-19 served as control. We evaluated LV global longitudinal strain (LV-GLS), arterial stiffness [carotid-femoral pulse wave velocity (cf-PWV)], and heart rate variability -standard deviation of normal RR intervals (SDNN). VAC was estimated as the ratio of cf-PWV to LV-GLS. Post-COVID-19 individuals (1-month post-hospital discharge) presented with impaired LV-GLS [-18.4%(3.1) vs. -22.0%(2.7), P < 0.001], cf-PWV [12.1 m/s (3.2) vs. 9.6 m/s (1.9), P < 0.001], SDNN [111.3 ms (22.6) vs. 147.2 ms (14.0), P < 0.001], and VAC [-0.68 (0.22) vs. -0.44 (0.10), P < 0.001] compared to control. LV-GLS, SDNN, and VAC improved at the 6-month follow-up however they did not reach control levels. In post-COVID-19 subjects, SDNN and VAC were correlated at the 1-month (R = 0.499, P = 0.003) and 6-month (R = 0.372, P = 0.04) follow-up. Long COVID-19 syndrome was associated with impaired LV-GLS, SDNN, and VAC. Post-COVID-19 subjects presented with autonomic dysregulation associated with aortic stiffness, ventricular-arterial impairment, and LV dysfunction, even 6-months post-hospital discharge. These abnormalities may be related to the presence of long COVID-19 syndrome.

COVID19 biomarkers: What did we learn from systematic reviews?

The coronavirus disease 2019 (COVID19) pandemic continues to represent a substantial public health concern. It can rapidly progress to severe disease, with poor prognosis and a high mortality risk. An early diagnosis and specific prognostic tools can help healthcare providers to start interventions promptly, understand the likely prognosis and to identify and treat timely individuals likely to develop severe disease with enhanced mortality risk. Here we focused on an impressive set of systematic reviews and meta-analyses that were performed since the start of the COVID19 pandemic and summarized their results related to the levels of hematologic, inflammatory, immunologic biomarkers as well as markers of cardiac, respiratory, hepatic, gastrointestinal and renal systems and their association with the disease progression, severity and mortality. The evidence outlines the significance of specific biomarkers, including inflammatory and immunological parameters (C-reactive protein, procalcitonin, interleukin-6), hematological (lymphocytes count, neutrophil-to-lymphocyte ratio, D-dimer, ferritin, red blood cell distribution width), cardiac (troponin, CK-MB, myoglobin), liver (AST, ALT, total bilirubin, albumin) and lung injury (Krebs von den Lungen-6) that can be used as prognostic biomarkers to aid the identification of high-risk patients and the prediction of serious outcomes, including mortality, in COVID19. Thus, these parameters should be used as essential tools for an early risk stratification and adequate intervention in improving disease outcomes in COVID19 patients.

Current Concepts and Future Applications of Non-Invasive Functional and Anatomical Evaluation of Coronary Artery Disease

Over the last decades, significant advances have been achieved in the treatment of coronary artery disease (CAD). Proper non-invasive diagnosis and appropriate management based on functional information and the extension of ischemia or viability remain the cornerstone in the fight against adverse CAD events. Stress echocardiography and single photon emission computed tomography are often used for the evaluation of ischemia. Advancements in non-invasive imaging modalities such as computed tomography (CT) coronary angiography and cardiac magnetic resonance imaging (MRI) have not only allowed non-invasive imaging of coronary artery lumen but also provide additional functional information. Other characteristics regarding the plaque morphology can be further evaluated with the latest modalities achieving a morpho-functional evaluation of CAD. Advances in the utilization of positron emission tomography (PET), as well as software advancements especially regarding cardiac CT, may provide additional prognostic information to a more evidence-based treatment decision. Since the armamentarium on non-invasive imaging modalities has evolved, the knowledge of the capabilities and limitations of each imaging modality should be evaluated in a case-by-case basis to achieve the best diagnosis and treatment decision. In this review article, we present the most recent advances in the noninvasive anatomical and functional evaluation of CAD.

Vaccination Against SARS-CoV-2 Protects from COVID-19-induced Endothelial Dysfunction

BACKGROUND

Coronavirus Disease-19 (COVID-19) is implicated in endotheliitis, which adversely affects cardiovascular events. The impact of vaccination with COVID-19 on the clinical outcome of patients is documented.

OBJECTIVE

To evaluate the impact of vaccination with COVID-19 on the severe acute respiratory syndrome, coronavirus-2 (SARS-CoV-2) infection-related endothelial impairment.

METHODS

We enrolled 45 patients hospitalized for COVID-19 (either vaccinated or not against SARS-CoV-2). Clinical and laboratory data were collected, and brachial artery flow-mediated dilation (FMD) was evaluated. Subjects without COVID-19 were used as the control group.

RESULTS

There was no difference in age (64.7 ± 7.5 years vs. 61.2 ± 11.1 years vs. 62.4 ± 9.5, p = 0.28), male sex (49% vs. 60% vs. 52%, p = 0.71), control subjects, vaccinated, and unvaccinated subjects with COVID-19, respectively. Of the patients with COVID-19, 44% were vaccinated against SARS-CoV-2. Unvaccinated COVID-19 patients had significantly impaired FMD compared to vaccinated COVID-19 patients and Control subjects (2.05 ± 2.41 % vs. 7.24 ± 2.52% vs. 7.36 ± 2.94 %, p <0.001). Importantly, post hoc tests revealed that unvaccinated COVID-19 patients had significantly impaired FMD from both Vaccinated COVID-19 subjects (p <0.001) and from Control subjects (p <0.001). There was no difference in FMD between the control group and the vaccinated COVID-19 group (p = 0.99).

CONCLUSION

Hospitalized patients with COVID-19 present endothelial dysfunction in the acute phase of the disease. Endothelial function in unvaccinated patients with COVID-19 is impaired compared to control subjects as well compared to vaccinated patients with COVID-19. Vaccinated hospitalized subjects with COVID-19 do not show endothelial dysfunction, strengthening the protective role of vaccination against SARS-CoV-2.

Implication of Neutrophils Extracellular Traps in the Pathogenesis of SARS-CoV-2 pneumonia

Peripheral blood polymorphonuclear neutrophils (PMNs) forming extracellular traps (NETs), as well as endothelial- and platelet-derived parameters, have been analyzed in patients with SARS-CoV-2 pneumonia, and their prognostic role has been evaluated. Eighty-seven consecutive patients hospitalized with SARS-CoV-2 pneumonia were prospectively selected. A sample of 30 healthy individuals served as the control group. Clinical and oxygenation (oxygen saturation to fraction of inspired oxygen ratio—SpO²/FiO²) characteristics and PMNs forming NETs, serum levels of myeloperoxidase, E-selectin, vascular cell adhesion molecule 1—VCAM1—vascular endothelial growth factor, P-selectin, platelet factor 4 and plasma concentrations of D-dimer were evaluated at hospital admission, at discharge and 14 days after discharge. Intensive care unit admission or death was the primary composite endpoint. Patients showed a higher number of PMNs forming NETs than healthy controls. The absolute number of PMNs forming NETs was inversely correlated with oxygen status (SpO²/FiO²) and positively with inflammatory (C-reactive protein, ferritin) markers and VCAM1. A decrease in, but not a normalization of NETs and endothelial-derived parameters was observed in patients who survived. In conclusion, the formation of NETs runs parallel to that of other inflammatory and endothelial activation markers, and is inverse to the oxygenation parameters, supporting a pathogenic role for PMNs in this entity.

Prognostic value of von Willebrand factor and ADAMTS13 in patients with COVID-19: A systematic review and meta-analysis

Background

Endotheliopathy and coagulopathy appear to be the main causes for critical illness and death in patients with coronavirus disease 2019 (COVID-19). The adhesive ligand von Willebrand factor (VWF) has been involved in immunothrombosis responding to endothelial injury. Here, we reviewed the current literature and performed meta-analyses on the relationship between both VWF and its cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13) with the prognosis of COVID-19.

Methods

We searched MEDLINE, Cochrane Library, Web of Science, and EMBASE databases from inception to 4 March 2022 for studies analyzing the relationship between VWF-related variables and composite clinical outcomes of patients with COVID-19. The VWF-related variables analyzed included VWF antigen (VWF:Ag), VWF ristocetin cofactor (VWF:Rco), ADAMTS13 activity (ADAMTS13:Ac), the ratio of VWF:Ag to ADAMTS13:Ac, and coagulation factor VIII (FVIII). The unfavorable outcomes were defined as mortality, intensive care unit (ICU) admission, and severe disease course. We used random or fixed effects models to create summary estimates of risk. Risk of bias was assessed based on the principle of the Newcastle-Ottawa Scale.

Results

A total of 3764 patients from 40 studies were included. The estimated pooled means indicated increased plasma levels of VWF:Ag, VWF:Rco, and VWF:Ag/ADAMTS13:Ac ratio, and decreased plasma levels of ADAMTS13:Ac in COVID-19 patients with unfavorable outcomes when compared to those with favorable outcomes (composite outcomes or subgroup analyses of non-survivor versus survivor, ICU versus non-ICU, and severe versus non-severe). In addition, FVIII were higher in COVID-19 patients with unfavorable outcomes. Subgroup analyses indicated that FVIII was higher in patients admitting to ICU, while there was no significant difference between non-survivors and survivors.

Conclusions

The imbalance of the VWF-ADAMTS13 axis (massive quantitative and qualitative increases of VWF with relative deficiency of ADAMTS13) is associated with poor prognosis of patients with COVID-19.

Mineralocorticoid receptor-antagonism prevents COVID-19-dependent glycocalyx damage

Proinflammatory cytokines target vascular endothelial cells during COVID-19 infections. In particular, the endothelial glycocalyx (eGC), a proteoglycan-rich layer on top of endothelial cells, was identified as a vulnerable, vasoprotective structure during infections. Thus, eGC damage can be seen as a hallmark in the development of endothelial dysfunction and inflammatory processes. Using sera derived from patients suffering from COVID-19, we could demonstrate that the eGC became progressively worse in relation to disease severity (mild vs severe course) and in correlation to IL-6 levels. This could be prevented by administering low doses of spironolactone, a well-known and highly specific aldosterone receptor antagonist. Our results confirm that SARS-CoV-2 infections cause eGC damage and endothelial dysfunction and we outline the underlying mechanisms and suggest potential therapeutic options.

Myocardial Ischemia in Patients with COVID-19 Infection: Between Pathophysiological Mechanisms and Electrocardiographic Findings

Given the possible pathophysiological links between myocardial ischemia and SARS-CoV-2 infection, several studies have focused attention on acute coronary syndromes in order to improve patients’ morbidity and mortality. Understanding the pathophysiological aspects of myocardial ischemia in patients infected with SARS-CoV-2 can open a broad perspective on the proper management for each patient. The electrocardiogram (ECG) remains the easiest assessment of cardiac involvement in COVID-19 patients, due to its non-invasive profile, accessibility, low cost, and lack of radiation. The ECG changes provide insight into the patient’s prognosis, indicating either the worsening of an underlying cardiac illnesses or the acute direct injury by the virus. This indicates that the ECG is an important prognostic tool that can affect the outcome of COVID-19 patients, which important to correlate its aspects with the clinical characteristics and patient’s medical history. The ECG changes in myocardial ischemia include a broad spectrum in patients with COVID-19 with different cases reported of ST-segment elevation, ST-segment depression, and T wave inversion, which are associated with severe COVID-19 disease.

Cardiovascular Biomarkers for Prediction of in-hospital and 1-Year Post-discharge Mortality in Patients With COVID-19 Pneumonia

Aims

While COVID-19 affects the cardiovascular system, the potential clinical impact of cardiovascular biomarkers on predicting outcomes in COVID-19 patients is still unknown. Therefore, to investigate this issue we analyzed the prognostic potential of cardiac biomarkers on in-hospital and long-term post-discharge mortality of patients with COVID-19 pneumonia.

Methods

Serum soluble ST2, VCAM-1, and hs-TnI were evaluated upon admission in 280 consecutive patients hospitalized with COVID-19-associated pneumonia in a single, tertiary care center. Patient clinical and laboratory characteristics and the concentration of biomarkers were correlated with in-hospital [Hospital stay: 11 days (10; 14)] and post-discharge all-cause mortality at 1 year follow-up [FU: 354 days (342; 361)].

Results

11 patients died while hospitalized for COVID-19 (3.9%), and 11 patients died during the 1-year post-discharge follow-up period (n = 11, 4.1%). Using multivariate analysis, VCAM-1 was shown to predict mortality during the hospital period (HR 1.081, CI 95% 1.035;1.129, p = 0.017), but not ST2 or hs-TnI. In contrast, during one-year FU post hospital discharge, ST2 (HR 1.006, 95% CI 1.002;1.009, p < 0.001) and hs-TnI (HR 1.362, 95% CI 1.050;1.766, p = 0.024) predicted mortality, although not VCAM-1.

Conclusion

In patients hospitalized with Covid-19 pneumonia, elevated levels of VCAM-1 at admission were associated with in-hospital mortality, while ST2 and hs-TnI might predict post-discharge mortality in long term follow-up.

The effect of prostacyclin infusion on markers of endothelial activation and damage in mechanically ventilated patients with SARS-CoV-2 infection

Background

In a pilot study, we found a significant reduction in mean daily sequential organ failure assessment score in mechanically ventilated patients with COVID-19 who received prostacyclin, compared to placebo. We here investigate the effect on biomarkers of endothelial activation and damage.

Methods

Post-hoc study of a randomized controlled trial in adult patients with confirmed SARS-CoV-2 infection, mechanically ventilated, with soluble thrombomodulin (sTM) plasma levels >4 ng/mL. Patients received prostacyclin infusion (1 ng/kg/min) or placebo. Blood samples were collected at baseline and 24 h.

Results

Eighty patients were randomized (41 prostacyclin, 39 placebo). The median changes in syndecan-1 plasma levels at 24 h were −3.95 (IQR: −21.1 to 2.71) ng/mL in the prostacyclin group vs. 3.06 (IQR: −8.73 to 20.5) ng/mL in the placebo group (difference of the medians: -7.01 [95% CI: −22.3 to −0.231] ng/mL, corresponding to −3% [95% CI: −11% to 0%], p = 0.04). Changes in plasma levels of sTM, PECAM-1, p-selectin, and CD40L did not differ significantly between groups.

Conclusions

Prostacyclin infusion, compared to placebo, resulted in a measurable decrease in endothelial glycocalyx shedding (syndecan-1) at 24 h, suggesting a protective effect on the endothelium, which may be related to the observed reduction in organ failure.

Endothelial Dysfunction in COVID-19: A Unifying Mechanism and a Potential Therapeutic Target

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) generated a worldwide emergency, until the declaration of the pandemic in March 2020. SARS-CoV-2 could be responsible for coronavirus disease 2019 (COVID-19), which goes from a flu-like illness to a potentially fatal condition that needs intensive care. Furthermore, the persistence of functional disability and long-term cardiovascular sequelae in COVID-19 survivors suggests that convalescent patients may suffer from post-acute COVID-19 syndrome, requiring long-term care and personalized rehabilitation. However, the pathophysiology of acute and post-acute manifestations of COVID-19 is still under study, as a better comprehension of these mechanisms would ensure more effective personalized therapies. To date, mounting evidence suggests a crucial endothelial contribution to the clinical manifestations of COVID-19, as endothelial cells appear to be a direct or indirect preferential target of the virus. Thus, the dysregulation of many of the homeostatic pathways of the endothelium has emerged as a hallmark of severity in COVID-19. The aim of this review is to summarize the pathophysiology of endothelial dysfunction in COVID-19, with a focus on personalized pharmacological and rehabilitation strategies targeting endothelial dysfunction as an attractive therapeutic option in this clinical setting.

COVID-19 and the Vasculature: Current Aspects and Long-Term Consequences

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was first identified in December 2019 as a novel respiratory pathogen and is the causative agent of Corona Virus disease 2019 (COVID-19). Early on during this pandemic, it became apparent that SARS-CoV-2 was not only restricted to infecting the respiratory tract, but the virus was also found in other tissues, including the vasculature. Individuals with underlying pre-existing co-morbidities like diabetes and hypertension have been more prone to develop severe illness and fatal outcomes during COVID-19. In addition, critical clinical observations made in COVID-19 patients include hypercoagulation, cardiomyopathy, heart arrythmia, and endothelial dysfunction, which are indicative for an involvement of the vasculature in COVID-19 pathology. Hence, this review summarizes the impact of SARS-CoV-2 infection on the vasculature and details how the virus promotes (chronic) vascular inflammation. We provide a general overview of SARS-CoV-2, its entry determinant Angiotensin-Converting Enzyme II (ACE2) and the detection of the SARS-CoV-2 in extrapulmonary tissue. Further, we describe the relation between COVID-19 and cardiovascular diseases (CVD) and their impact on the heart and vasculature. Clinical findings on endothelial changes during COVID-19 are reviewed in detail and recent evidence from in vitro studies on the susceptibility of endothelial cells to SARS-CoV-2 infection is discussed. We conclude with current notions on the contribution of cardiovascular events to long term consequences of COVID-19, also known as “Long-COVID-syndrome”. Altogether, our review provides a detailed overview of the current perspectives of COVID-19 and its influence on the vasculature.

Endothelial dysfunction in acute and long standing COVID−19: A prospective cohort study

Background

Coronavirus disease-19 (COVID-19) is implicated by active endotheliitis, and cardiovascular morbidity. The long-COVID-19 syndrome implications in atherosclerosis have not been elucidated yet. We assessed the immediate, intermediate, and long-term effects of COVID-19 on endothelial function.

Methods

In this prospective cohort study, patients hospitalized for COVID-19 at the medical ward or Intensive Care Unit (ICU) were enrolled and followed up to 6 months post-hospital discharge. Medical history and laboratory examinations were performed while the endothelial function was assessed by brachial artery flow-mediated dilation (FMD). Comparison with propensity score-matched cohort (control group) was performed at the acute (upon hospital admission) and follow-up (1 and 6 months) stages.

Results

Seventy-three patients diagnosed with COVID-19 (37% admitted in ICU) were recruited. FMD was significantly (p < 0.001) impaired in the COVID-19 group (1.65 ± 2.31%) compared to the control (6.51 ± 2.91%). ICU-treated subjects presented significantly impaired (p = 0.001) FMD (0.48 ± 1.01%) compared to those treated in the medical ward (2.33 ± 2.57%). During hospitalization, FMD was inversely associated with Interleukin-6 and Troponin I (p < 0.05 for all). Although, a significant improvement in FMD was noted during the follow-up (acute: 1.75 ± 2.19% vs. 1 month: 4.23 ± 2.02%, vs. 6 months: 5.24 ± 1.62%; p = 0.001), FMD remained impaired compared to control (6.48 ± 3.08%) at 1 month (p < 0.001) and 6 months (p = 0.01) post-hospital discharge.

Conclusion

COVID-19 patients develop a notable endothelial dysfunction, which is progressively improved over a 6-month follow-up but remains impaired compared to healthy controls subjects. Whether chronic dysregulation of endothelial function following COVID-19 could be accompanied by a residual risk for cardiovascular and thrombotic events merits further research.