SARS-CoV-2 infection causes prolonged cardiomyocyte swelling and inhibition of HIF1α translocation in an animal model COVID-19

Myocardial Oedema as a Consequence of Viral Infection and Persistence-A Narrative Review with Focus on COVID-19 and Post COVID Sequelae

Microvascular integrity is a critical factor in myocardial fluid homeostasis. The subtle equilibrium between capillary filtration and lymphatic fluid removal is disturbed during pathological processes leading to inflammation, but also in hypoxia or due to alterations in vascular perfusion and coagulability. The degradation of the glycocalyx as the main component of the endothelial filtration barrier as well as pericyte disintegration results in the accumulation of interstitial and intracellular water. Moreover, lymphatic dysfunction evokes an increase in metabolic waste products, cytokines and inflammatory cells in the interstitial space contributing to myocardial oedema formation. This leads to myocardial stiffness and impaired contractility, eventually resulting in cardiomyocyte apoptosis, myocardial remodelling and fibrosis. The following article reviews pathophysiological inflammatory processes leading to myocardial oedema including myocarditis, ischaemia-reperfusion injury and viral infections with a special focus on the pathomechanisms evoked by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In addition, clinical implications including potential long-term effects due to viral persistence (long COVID), as well as treatment options, are discussed.

Mechanism of COVID-19-Induced Cardiac Damage from Patient, In Vitro and Animal Studies

PURPOSE OF REVIEW

Though patient studies have been important for understanding the disease, research done in animals and cell culture complement our knowledge from patient data and provide insight into the mechanism of the disease. Understanding how COVID causes damage to the heart is essential to understanding possible long-term consequences.

RECENT FINDINGS

COVID-19 is primarily a disease that attacks the lungs; however, it is known to have important consequences in many other tissues including the heart. Though myocarditis does occur in some patients, for most cases of cardiac damage, the injury arises from scarring either due to myocardial infarction or micro-infarction. The main focus is on how COVID affects blood flow through the coronaries. We review how endothelial activation leads to a hypercoagulative state in COVID-19. We also emphasize the effects that the cytokine storm can directly have on the regulation of coronary blood flow. Since the main two cell types that can be infected in the heart are pericytes and cardiomyocytes, we further describe the known effects on pericyte function and how that can further lead to microinfarcts within the heart. Though many of these effects are systemic, this review focuses on the consequences on cardiac tissue of this dysregulation and the role that it has in the formation of myocardial scarring.

Serial echocardiographic evaluation of COVID-19 patients without prior history of structural heart disease: a 1-year follow-up CRACoV-HHS study

Background

It is a well-known fact that COVID-19 affects the cardiovascular system by exacerbating heart failure in patients with preexisting conditions. However, there is a poor insight into the cardiovascular involvement and sequelae in patients without preexisting conditions. The aim of the study is to analyse the influence of COVID-19 on cardiac performance in patients without prior history of structural heart disease. The study is part of the CRACoV project, which includes a prospective design and a 12-month follow-up period.

Material and methods

The study included 229 patients hospitalised with a diagnosis of COVID-19 (median age of 59 years, 81 were women). A standard clinical assessment and laboratory tests were performed in all participants. An extended echocardiographic image acquisition was performed at baseline and at a 3-, 6-, and 12-month follow-up. All analyses were performed off-line. A series of echocardiographic parameters was compared using repeated measures or Friedman analysis of variance.

Results

In all subjects, the left ventricular (LV) ejection fraction at baseline was preserved [63.0%; Q1:Q3 (60.0-66.0)]. Elevated levels of high-sensitivity cardiac troponin T were detected in 21.3% of the patients, and elevated NT-proBNP levels were detected in 55.8%. At the 1-year follow-up, no significant changes were observed in the LV diameter and volume (LV 48.0 ± 5.2 vs. 47.8 ± 4.8 mm, p = 0.08), while a significant improvement of the parameters in the biventricular strain was observed (LV -19.1 ± 3.3% vs. -19.7 ± 2.5%, p = 0.01, and right ventricular -19.9 ± 4.5% vs. -23.2 ± 4.9%, p = 0.002). In addition, a decrease in the LV wall thickness was also observed (interventricular septum 10.4 ± 1.6 vs. 9.7 ± 2.0 mm, p < 0.001; LV posterior wall 9.8 ± 1.4 vs. 9.1 ± 1.5 mm, p < 0.001).

Conclusions

In an acute phase of COVID-19, the elevation of cardiac biomarkers in patients with normal left ventricular ejection fraction is a frequent occurrence; however, it does not translate into clinically significant cardiac dysfunction after 1 year. The serial echocardiographic evaluations conducted in patients without preexisting structural heart disease demonstrate an overall trend towards an improved cardiac function and a reduced myocardial thickening at 1-year follow-up. This suggests that the acute cardiac consequences of COVID-19 are associated with systemic inflammation and haemodynamic stress in patients without preexisting conditions.

Pericyte Loss in Diseases

Pericytes are specialized cells located in close proximity to endothelial cells within the microvasculature. They play a crucial role in regulating blood flow, stabilizing vessel walls, and maintaining the integrity of the blood-brain barrier. The loss of pericytes has been associated with the development and progression of various diseases, such as diabetes, Alzheimer's disease, sepsis, stroke, and traumatic brain injury. This review examines the detection of pericyte loss in different diseases, explores the methods employed to assess pericyte coverage, and elucidates the potential mechanisms contributing to pericyte loss in these pathological conditions. Additionally, current therapeutic strategies targeting pericytes are discussed, along with potential future interventions aimed at preserving pericyte function and promoting disease mitigation.

COVID-19, Myocarditis and Pericarditis

Viral infections are a leading cause of myocarditis and pericarditis worldwide, conditions that frequently coexist. Myocarditis and pericarditis were some of the early comorbidities associated with SARS-CoV-2 infection and COVID-19. Many epidemiologic studies have been conducted since that time concluding that SARS-CoV-2 increased the incidence of myocarditis/pericarditis at least 15× over pre-COVID levels although the condition remains rare. The incidence of myocarditis pre-COVID was reported at 1 to 10 cases/100 000 individuals and with COVID ranging from 150 to 4000 cases/100 000 individuals. Before COVID-19, some vaccines were reported to cause myocarditis and pericarditis in rare cases, but the use of novel mRNA platforms led to a higher number of reported cases than with previous platforms providing new insight into potential pathogenic mechanisms. The incidence of COVID-19 vaccine-associated myocarditis/pericarditis covers a large range depending on the vaccine platform, age, and sex examined. Importantly, the findings highlight that myocarditis occurs predominantly in male patients aged 12 to 40 years regardless of whether the cause was due to a virus-like SARS-CoV-2 or associated with a vaccine-a demographic that has been reported before COVID-19. This review discusses findings from COVID-19 and COVID-19 vaccine-associated myocarditis and pericarditis considering the known symptoms, diagnosis, management, treatment, and pathogenesis of disease that has been gleaned from clinical research and animal models. Sex differences in the immune response to COVID-19 are discussed, and theories for how mRNA vaccines could lead to myocarditis/pericarditis are proposed. Additionally, gaps in our understanding that need further research are raised.