COVID-19 Pathogenesis: From Molecular Pathway to Vaccine Administration

Thromboembolic Disease and Cardiac Thrombotic Complication in COVID-19: A Systematic Review

The coronavirus 2019 pandemic has affected many healthcare systems worldwide. While acute respiratory distress syndrome (ARDS) has been well-documented in COVID-19, there are several cardiovascular complications, such as myocardial infarction, ischaemic stroke, and pulmonary embolism, leading to disability and death. The link between COVID-19 and increasing thrombogenicity potentially occurs due to numerous different metabolic mechanisms, ranging from endothelial damage for direct virus infection, associated excessive formation of neutrophil extracellular traps (NETs), pathogenic activation of the renin-angiotensin-aldosterone system (RAAS), direct myocardial injury, and ischemia induced by respiratory failure, all of which have measurable biomarkers. A search was performed by interrogating three databases (MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations, and EMBASE). Evidence from randomized controlled trials (RCT), prospective series, meta-analyses, and unmatched observational studies were evaluated for the processing of the algorithm and treatment of thromboembolic disease and cardiac thrombotic complications related to COVID-19 during SARS-CoV-2 infection. Studies out with the SARS-Cov-2 infection period and case reports were excluded. A total of 58 studies were included in this analysis. The role of the acute inflammatory response in the propagation of the systemic inflammatory sequelae of the disease plays a major part in determining thromboembolic disease and cardiac thrombotic complication in COVID-19. Some of the mechanisms of activation of these pathways, alongside the involved biomarkers noted in previous studies, are highlighted. Inflammatory response led to thromboembolic disease and cardiac thrombotic complications in COVID-19. NETs play a pivotal role in the pathogenesis of the inflammatory response. Despite moving into the endemic phase of the disease in most countries, thromboembolic complications in COVID-19 remain an entity that substantially impacts the health care system, with long-term effects that remain uncertain. Continuous monitoring and research are required.

Antigen transfer and its effect on vaccine-induced immune amplification and tolerance

Antigen transfer refers to the process of intercellular information exchange, where antigenic components including nucleic acids, antigen proteins/peptides and peptide-major histocompatibility complexes (p-MHCs) are transmitted from donor cells to recipient cells at the thymus, secondary lymphoid organs (SLOs), intestine, allergic sites, allografts, pathological lesions and vaccine injection sites via trogocytosis, gap junctions, tunnel nanotubes (TNTs), or extracellular vesicles (EVs). In the context of vaccine inoculation, antigen transfer is manipulated by the vaccine type and administration route, which consequently influences, even alters the immunological outcome, i.e., immune amplification and tolerance. Mainly focused on dendritic cells (DCs)-based antigen receptors, this review systematically introduces the biological process, molecular basis and clinical manifestation of antigen transfer.

Insights into the Role of Neutrophils and Neutrophil Extracellular Traps in Causing Cardiovascular Complications in Patients with COVID-19: A Systematic Review

Background: The coronavirus disease 2019 (COVID-19) pandemic caused by the SARS-CoV-2 virus has resulted in significant mortality and burdening of healthcare resources. While initially noted as a pulmonary pathology, subsequent studies later identified cardiovascular involvement with high mortalities reported in specific cohorts of patients. While cardiovascular comorbidities were identified early on, the exact manifestation and etiopathology of the infection remained elusive. This systematic review aims to investigate the role of inflammatory pathways, highlighting several culprits including neutrophil extracellular traps (NETs) which have since been extensively investigated. Method: A search was conducted using three databases (MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations and EMBASE). Data from randomized controlled trials (RCT), prospective series, meta-analyses, and unmatched observational studies were considered for the processing of the algorithm and treatment of inflammatory response during SARS-CoV-2 infection. Studies without the SARS-CoV-2 Infection period and case reports were excluded. Results: A total of 47 studies were included in this study. The role of the acute inflammatory response in the propagation of the systemic inflammatory sequelae of the disease plays a major part in determining outcomes. Some of the mechanisms of activation of these pathways have been highlighted in previous studies and are highlighted. Conclusion: NETs play a pivotal role in the pathogenesis of the inflammatory response. Despite moving into the endemic phase of the disease in most countries, COVID-19 remains an entity that has not been fully understood with long-term effects remaining uncertain and requiring ongoing monitoring and research.

Molecular Insights of SARS-CoV-2 Antivirals Administration: A Balance between Safety Profiles and Impact on Cardiovascular Phenotypes

The COVID-19 pandemic has resulted in a complex clinical challenge, caused by a novel coronavirus, partially similar to previously known coronaviruses but with a different pattern of contagiousness, complications, and mortality. Since its global spread, several therapeutic agents have been developed to address the heterogeneous disease treatment, in terms of severity, hospital or outpatient management, and pre-existing clinical conditions. To better understand the rationale of new or old repurposed medications, the structure and host-virus interaction molecular bases are presented. The recommended agents by EDSA guidelines comprise of corticosteroids, JAK-targeting monoclonal antibodies, IL-6 inhibitors, and antivirals, some of them showing narrow indications due to the lack of large population trials and statistical power. The aim of this review is to present FDA-approved or authorized for emergency use antivirals, namely remdesivir, molnupinavir, and the combination nirmatrelvir-ritonavir and their impact on the cardiovascular system. We reviewed the literature for metanalyses, randomized clinical trials, and case reports and found positive associations between remdesivir and ritonavir administration at therapeutic doses and changes in cardiac conduction, relatable to their previously known pro-arrhythmogenic effects and important ritonavir interactions with cardioactive medications including antiplatelets, anti-arrhythmic agents, and lipid-lowering drugs, possibly interfering with pre-existing therapeutic regimens. Nonetheless, safety profiles of antivirals are largely questioned and addressed by health agencies, in consideration of COVID-19 cardiac and pro-thrombotic complications generally experienced by predisposed subjects. Our advice is to continuously adhere to the strict indications of FDA documents, monitor the possible side effects of antivirals, and increase physicians' awareness on the co-administration of antivirals and cardiovascular-relevant medications. This review dissects the global and local tendency to structure patient-based treatment plans, for a glance towards practical application of precision medicine.

Alterations in Circulating Monocytes Predict COVID-19 Severity and Include Chromatin Modifications Still Detectable Six Months after Recovery

An early analysis of circulating monocytes may be critical for predicting COVID-19 course and its sequelae. In 131 untreated, acute COVID-19 patients at emergency room arrival, monocytes showed decreased surface molecule expression, including low HLA-DR, in association with an inflammatory cytokine status and limited anti-SARS-CoV-2-specific T cell response. Most of these alterations had normalized in post-COVID-19 patients 6 months after discharge. Acute COVID-19 monocytes transcriptome showed upregulation of anti-inflammatory tissue repair genes such as BCL6, AREG and IL-10 and increased accessibility of chromatin. Some of these transcriptomic and epigenetic features still remained in post-COVID-19 monocytes. Importantly, a poorer expression of surface molecules and low IRF1 gene transcription in circulating monocytes at admission defined a COVID-19 patient group with impaired SARS-CoV-2-specific T cell response and increased risk of requiring intensive care or dying. An early analysis of monocytes may be useful for COVID-19 patient stratification and for designing innate immunity-focused therapies.