COVID-19 and the Cardiovascular System: An Update

Phenotypic switch of vascular smooth muscle cells in COVID-19: Role of cholesterol, calcium, and phosphate

Although the novel coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily manifests as severe respiratory distress, its impact on the cardiovascular system is also notable. Studies reveal that COVID-19 patients often suffer from certain vascular diseases, partly attributed to increased proliferation or altered phenotype of vascular smooth muscle cells (VSMCs). Although the association between COVID-19 and VSMCs is recognized, the precise mechanism underlying SARS-CoV-2's influence on VSMC phenotype remains largely under-reviewed. In this context, while there is a consistent body of literature dissecting the effect of COVID-19 on the cardiovascular system, few reports delve into the potential role of VSMC switching in the pathophysiology associated with COVID-19 and the molecular mechanisms involved therein. This review dissects and critiques the link between COVID-19 and VSMCs, with particular attention to pathways involving cholesterol, calcium, and phosphate. These pathways underpin the interaction between the virus and VSMCs. Such interaction promotes VSMC proliferation, and eventually potentiates vascular calcification as well as worsens prognosis in patients with COVID-19.

Cardiovascular Comorbidities in COVID-19: Comprehensive Analysis of Key Topics

BACKGROUND

The interrelation between COVID-19 and various cardiovascular and metabolic disorders has been a critical area of study. There is a growing need to understand how comorbidities such as cardiovascular diseases (CVDs) and metabolic disorders affect the risk and severity of COVID-19.

OBJECTIVE

The objective of this study is to systematically analyze the association between COVID-19 and cardiovascular and metabolic disorders. The focus is on comorbidity, examining the roles of CVDs such as embolism, thrombosis, hypertension, and heart failure, as well as metabolic disorders such as disorders of glucose and iron metabolism.

METHODS

Our study involved a systematic search in PubMed for literature published from 2000 to 2022. We established 2 databases: one for COVID-19-related articles and another for CVD-related articles, ensuring all were peer-reviewed. In terms of data analysis, statistical methods were applied to compare the frequency and relevance of MeSH (Medical Subject Headings) terms between the 2 databases. This involved analyzing the differences and ratios in the usage of these terms and employing statistical tests to determine their significance in relation to key CVDs within the COVID-19 research context.

RESULTS

The study revealed that "Cardiovascular Diseases" and "Nutritional and Metabolic Diseases" were highly relevant as level 1 Medical Subject Headings descriptors in COVID-19 comorbidity research. Detailed analysis at level 2 and level 3 showed "Vascular Disease" and "Heart Disease" as prominent descriptors under CVDs. Significantly, "Glucose Metabolism Disorders" were frequently associated with COVID-19 comorbidities such as embolism, thrombosis, and heart failure. Furthermore, iron deficiency (ID) was notably different in its occurrence between COVID-19 and CVD articles, underlining its significance in the context of COVID-19 comorbidities. Statistical analysis underscored these differences, highlighting the importance of both glucose and iron metabolism disorders in COVID-19 research.

CONCLUSIONS

This work lays the foundation for future research that utilizes a knowledge-based approach to elucidate the intricate relationships between these conditions, aiming to develop more effective health care strategies and interventions in the face of ongoing pandemic challenges.

Factors influencing cardiovascular system-related post-COVID-19 sequelae: A single-center cohort study

Background

COVID-19 sequelae are long-term symptoms of COVID-19. Cardiovascular disease is not only a risk factor for the occurrence of COVID-19 sequelae but also a potential result directly or indirectly caused by COVID-19 infection.

Objectives

The aim of this study is to investigate the cardiovascular system-related symptoms of outpatients and inpatients of the Cardiovascular Department of the Affiliated Hospital of Shandong University of Traditional Chinese Medicine after recovery from novel coronavirus infection, analyze the influencing factors, and symptom characteristics of related symptoms, and thereby provide a basis for further formulating a reasonable diagnosis and treatment plan.

Materials and methods

From January 15, 2023 to February 15, 2023, 452 recovered patients with novel coronavirus infection who were admitted to the Cardiovascular Department of the Affiliated Hospital of Shandong University of Traditional Chinese Medicine due to symptoms of the cardiovascular system (complaints of chest pain and palpitations) were involved in this study. A unified questionnaire was used to record the general information, past medical history, characteristics of chest pain or palpitations, and other COVID-19-related sequelae of the selected patients. All data were statistically analyzed by SPSS 26.0 statistical software.

Results

A total of 226 patients with cardiovascular symptoms and 226 patients without cardiovascular symptoms were included in this study. After univariate and multivariate logistic regression analysis, women (OR 2.081, 95% CI = 1.358-3.189) and young people (OR 2.557, 95% CI = 1.44-4.54) had a higher risk of cardiovascular symptoms; prehypertension (OR 1.905, 95% CI = 1.091-3.329) and hypertension (OR 2.287, 95% CI = 1.433-3.649) increased the risk of cardiovascular symptoms; patients with history of previous cardiovascular disease (OR 1.862, 95% CI = 1.16-2.988) and history of diabetes (OR 2.138, 95% CI = 1.058-4.319) had a higher risk of developing cardiovascular symptoms. The main symptoms related to COVID-19 sequelae reported by all 452 patients were fatigue (76.8%), shortness of breath (54.2%), dry mouth and bitter mouth (46.0%), gastrointestinal symptoms (42.7%), sleep disturbances (37.4%), sweating (31.9%), chills (29%), dizziness (25.7%), confusion of brain fog (25.2%), and tinnitus (14.6%). Compared with patients without cardiovascular symptoms, patients with cardiovascular symptoms were more likely to have shortness of breath (OR 3.521, 95% CI = 2.226-5.472), gastrointestinal symptoms (OR 2.039, 95% CI = 1.226-3.393), and dry mouth and bitter mouth (OR 1.918, 95% CI = 1.229-2.992). The differences were statistically significant (P < 0.05).

Conclusion

In this new coronavirus infection, women, young people, the elderly, people with prehypertension, hypertension, and patients with a history of cardiovascular disease and diabetes have a higher risk of developing cardiovascular symptoms, and patients with cardiovascular symptoms are more likely to develop other COVID-19 sequelae.

Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID

SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.

The COVID-19 inflammation and high mortality mechanism trigger

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lasted from March 2020 to May 2023, infecting over 689 million and causing 6.9 million deaths globally. SARS-CoV-2 enters human cells via the spike protein binding to ACE2 receptors, leading to viral replication and an exaggerated immune response characterized by a "cytokine storm." This review analyzes the COVID-19 pathogenesis, strains, risk factors for severe disease, and vaccine types and effectiveness. A systematic literature search for 2020-2023 was conducted. Results show the cytokine storm underlies COVID-19 pathogenesis, causing multiorgan damage. Key viral strains include Alpha, Beta, Gamma, Delta, and Omicron, differing in transmissibility, disease severity, and vaccine escape. Risk factors for severe COVID-19 include older age, obesity, and comorbidities. mRNA, viral vector, and inactivated vaccines effectively prevent hospitalization and death, although new variants exhibit some vaccine escape. Ongoing monitoring of emerging strains and vaccine effectiveness is warranted. This review provides updated information on COVID-19 pathogenesis, viral variants, risk factors, and vaccines to inform public health strategies for containment and treatment.

Association of COVID-19 and Arterial Stiffness Assessed using Cardiovascular Index (CAVI)

BACKGROUND

COVID-19 is characterized by an acute inflammatory response with the formation of endothelial dysfunction and may affect arterial stiffness. Studies of cardio-ankle vascular index in COVID-19 patients with considered cardiovascular risk factors have not been conducted.

OBJECTIVE

The purpose of our study was to assess the association between cardio-ankle vascular index and COVID-19 in hospitalized patients adjusted for known cardiovascular risk factors.

METHODS

A cross-sectional study included 174 people hospitalized with a diagnosis of moderate COVID-19 and 94 people without COVID-19. Significant differences in the cardio-ankle vascular index values measured by VaSera VS - 1500N between the two groups were analyzed using parametric (Student's t-criterion) and nonparametric (Mann-Whitney) criteria. Independent association between COVID-19 and an increased cardio-ankle vascular index ≥ 9.0 adjusted for known cardiovascular risk factors was assessed by multivariate logistic regression.

RESULTS

There were significantly higher values of the right cardio-ankle vascular index 8.10 [7.00;9.40] and the left cardio-ankle vascular index 8.10 [6.95;9.65] in patients undergoing inpatient treatment for COVID-19 than in the control group - 7.55 [6.60;8.60] and 7.60 [6.60;8.70], respectively. A multivariate logistic regression model adjusted for age, hypertension, plasma glucose level, glomerular filtration rate and diabetes mellitus showed a significant association between increased cardio-ankle vascular index and COVID-19 (OR 2.41 [CI 1.09;5.30]).

CONCLUSION

Hospitalized patients with COVID-19 had significantly higher cardio-ankle vascular index values compared to the control group. An association between an increased cardio-ankle vascular index and COVID-19 was revealed, independent of age, hypertension, plasma glucose level, glomerular filtration rate and diabetes mellitus.

The Effects of the COVID-19 Pandemic on the Clinical Practices of Cardiologists

Cardiology clinics' activities were affected by the COVID-19 pandemic. The aim of this study was to examine how the pandemic changed the anxiety levels of cardiologists and their management of patients with acute coronary syndrome (ACS). A survey was conducted among 375 cardiologists and data on their demographics, anxiety levels, ACS patients and their treatment, coronary angiography and percutaneous coronary interventions preferences were collected. It was found that 41.9% of the cardiologists had moderate or higher anxiety disorder. The results also showed that fewer ACS patients came to the hospital, and they came later than usual. A decrease in CAG/PCI rates for NSTEMI and USAP patients, and an increase in thrombolytic therapy for STEMI patients were observed.The psychological state of cardiologists, the care of ACS patients and the procedural activities were disrupted by the COVID-19 pandemic.

Clinical indications and outcomes of Impella devices for severe cardiogenic shock in COVID-19 patients: a systematic review

Background

Coronavirus disease 2019 (COVID-19) can present with significant cardiac dysfunction, including cardiogenic shock. Mechanical circulatory support with an Impella device may be utilized in these patients to support and offload native right ventricle (RV) and left ventricle (LV) functions. This systematic review aims to describe clinical indications, management, laboratory data, and outcomes in patients with severe cardiogenic shock from COVID-19 treated with an Impella device.

Methods

A PRISMA-directed systematic review was performed and prospectively registered in PROSPERO. The databases accessed included PubMed/MEDLINE, Scopus, and ScienceDirect. Quality and risk of bias assessments were completed using the Joanna Briggs Institute (JBI) checklist for case reports.

Results

A total of 16 records were included in the qualitative synthesis; 8/16 (50%) of the patients were men. The average age was 39 years (SD: 14.7). The biventricular Impella (BiPella) approach was recorded in 3/16 (18.75%) patients. A total of 4/16 (25%) individuals required renal replacement therapy (RRT). Single-device usage was observed in three cases: 2/16 Impella CP (12.5%) and 1/16 Impella RP (6.25%). Treatment of COVID-19 myocarditis included a wide range of antivirals and immunomodulators; 8/16 (50%) cases needed ECMO (extracorporeal membrane oxygenation) support. Overall, only 2/16 (11.7%) individuals died.

Conclusions

Sixteen reported individuals have received an Impella implanted with a mortality rate of 11.7%. Concurrent use of RRT and ECMO implantation was often observed. Overall, the Impella device is an effective and safe strategy in the management of COVID-19-related cardiogenic shock. Future studies should include long-term results.

Cardiovascular Complications of COVID-19: A Scoping Review of Evidence

This scoping review sought to identify the nature and extent of clinical evidence regarding the acute and long-term cardiovascular complications associated with COVID-19. Forty-nine studies published between 2020 and 2023 were selected for review. The studies were divided into two groups. The referential group included 22 studies. The second group of 27 studies was used for a detailed review to assess the strength of the evidence. The aggregate evidence indicates that the most common cardiac complications associated with COVID-19 include but are not limited to acute pericarditis, acute myocardial injury, acute myocarditis, various arrhythmias, microvascular angiopathy, left ventricular dysfunction, heart failure, acute cardiac injury, and acute coronary syndrome. Clinical and epidemiological implications of the findings are investigated, and future research recommendations are proposed.

Impact of pre-existing depression on severe COVID-19 outcomes

The outbreak of the COVID-19 virus in 2019 had rapidly developed into a global pandemic, causing more than 6.8 million deaths and impacting the lives of billions of individuals around the world.1 Public healthcare around the work have mainly focused on the clinical manifestations and treatment of the deadly respiratory disease. As the pandemic progressed, it became clear that the psychological distress—arising from anxiety, depression and self-isolation; leading even to some suicides—had negatively impacted people’s mental health.2 However, whether pre-existing mental disorder has an influence on COVID-19 outcomes remains unknown.

Comparative Study of the Myocardium of Patients from Four COVID-19 Waves

BACKGROUND

Few studies have compared COVID-19 patients from different waves. This study aims to conduct a clinical and morphological analysis of patients who died from COVID-19 during four waves.

METHODS

The study involved 276 patients who died from COVID-19 during four waves, including 77 patients in the first wave, 119 patients in the second wave, and 78 patients in the third wave. We performed a histological examination of myocardium samples from autopsies and additionally analyzed the samples by PCR. We conducted immunohistochemistry of the myocardium for 21 samples using antibodies against CD3, CD45, CD8, CD68, CD34, Ang1, VWF, VEGF, HLA-DR, MHC1, C1q, enteroviral VP1, and SARS-CoV-2 spike protein. We also did immunofluorescent staining of three myocardial specimens using VP1/SARS-CoV-2 antibody cocktails. Further, we ran RT-ddPCR analysis for 14 RNA samples extracted from paraffin-embedded myocardium. Electron microscopic studies of the myocardium were also performed for two samples from the fourth wave.

RESULTS

Among the 276 cases, active myocarditis was diagnosed in 5% (15/276). Of these cases, 86% of samples expressed VP1, and individual cells contained SARS-CoV-2 spike protein in 22%. Immunofluorescence confirmed the co-localization of VP1 and SARS-CoV-2 spike proteins. ddPCR did not confidently detect SARS-CoV-2 RNA in the myocardium in any myocarditis cases. However, the myocardium sample from wave IV detected a sub-threshold signal of SARS-CoV-2 by qPCR, but myocarditis in this patient was not confirmed. Electron microscopy showed several single particles similar to SARS-CoV-2 virions on the surface of the endothelium of myocardial vessels. A comparison of the cardiovascular complication incidence between three waves revealed that the incidence of hemorrhage (48 vs. 24 vs. 17%), myocardial necrosis (18 vs. 11 vs. 4%), blood clots in the intramural arteries (12 vs. 7 vs. 0%), and myocarditis (19 vs. 1 vs. 6%) decreased over time, and CD8-T-killers appeared. Immunohistochemistry confirmed the presence of endotheliitis in all 21 studied cases.

CONCLUSIONS

This study compared myocardial damage in patients who died during three COVID-19 waves and showed a decrease in the incidence of endotheliitis complications (thrombosis, hemorrhage, necrosis) and myocarditis over time. However, the connection between myocarditis and SARS-CoV-2 infection remains unproven.

COVID-19-Induced Complete Heart Block: Case Series and Literature Review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to the emergence of a wide range of complications, including those affecting the cardiovascular system. In this case series, we present four patients who developed complete atrioventricular block, a serious and potentially life-threatening heart rhythm disorder, during the course of their coronavirus disease 2019 (COVID-19) illness. The mechanisms by which SARS-CoV-2 may lead to arrhythmias are not fully understood but may involve direct infection and damage to heart tissue, as well as inflammation and cytokine storms. The extent and duration of complete heart block varied among these cases, highlighting the need for further research to understand the spectrum of disease and to improve mortality and morbidity in future waves of SARS-CoV-2 infections. We hope that this case series will draw attention to this serious complication of COVID-19 and inspire further research to improve management and outcomes for affected patients.

Short and Long-Term Cardiovascular Sequelae after SARS-CoV-2 Infection: A Narrative Review Focusing on Athletes

Cardiovascular (CV) involvement after severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection was found to be frequent among the general population, especially in the pre-vaccination era, and particularly for hospitalized patients or those who experienced a more severe course of the disease. The spectrum of CV disease varies; however, acute myocarditis is particularly fearsome for the athletic population due to the possible associated risk of malignant arrhythmias during training. Alarming percentages of CV injuries, even in young and healthy athletes with a benign course of the disease, arose from a few initial studies limited to case series. Subsequent single-center studies and larger observational registries reported a lower prevalence of SARS-CoV2 CV involvement in athletes. Studies showing the occurrence of CV adverse events during follow-up periods are now available. The objective of our narrative review is to provide an updated summary of the literature on CV involvement after coronavirus disease 2019, both in the early post-infection period and over a longer period of time, with a focus on athletic populations.

Acute liver injury in COVID-19 patients hospitalized in the intensive care unit: Narrative review

In recent years, humanity has been confronted with a global pandemic due to coronavirus disease 2019 (COVID-19), which has caused an unprecedented health and economic crisis worldwide. Apart from the respiratory symptoms, which are considered the principal manifestations of COVID-19, it has been recognized that COVID-19 constitutes a systemic inflammatory process affecting multiple organ systems. Across the spectrum of organ involvement in COVID-19, acute liver injury (ALI) has been gradually gaining increasing attention by the international scientific community. COVID-19 associated liver impairment can affect a considerable proportion of COVID-19 patients and seems to correlate with the severity of the disease course. Indeed, COVID-19 patients hospitalized in the intensive care unit (ICU) run a greater risk of developing ALI due to the severity of their clinical condition and in the context of multi-organ failure. The putative pathophysiological mechanisms of COVID-19 induced ALI in ICU patients remain poorly understood and appear to be multifactorial in nature. Several theories have been proposed to explain the occurrence of ALI in the ICU setting, such as hypoperfusion and ischemia due to hemodynamic instability, passive liver congestion as a result of congestive heart failure, ischemia-reperfusion injury, hypoxia due to respiratory failure, mechanical ventilation itself, sepsis and septic shock, cytokine storm, endotheliitis with concomitant coagulopathy, drug-induced liver injury, parenteral nutrition and direct cytopathic viral effect. It should be noted that no specific therapy for COVID-19 induced ALI exists. Therefore, the therapeutic approach lies in preventive measures and is exclusively supportive once ALI ensues. The aim of the current review is to scrutinize the existing evidence on COVID-19 associated ALI in ICU patients, explore its clinical implications, shed light on the underlying pathophysiological mechanisms and propose potential therapeutic approaches. Ongoing research on the particular scientific field will further elucidate the pathophysiology behind ALI and address unresolved issues, in the hope of mitigating the tremendous health consequences imposed by COVID-19 on ICU patients.

Review of SARS-COV-2 Systemic Impact: Building the Case for Sepsis via Virus in the Circulatory System

SARS-COV-2 can contribute to long term consequences associated with sepsis and circulatory dysfunction. In this insightful paper, we highlight the emerging pathophysiology utilizing two case examples. Both systemic and organ specific features are discussed. In addition, a novel laboratory assay is presented that identified SARS-COV-2 in the circulation using conserved SARS ion channels rather than the spike protein. The presentation is linked to the pathophysiology with the emphasis for early recognition and continued research. This paper will serve as a catalyst for continued discovery.

Cardiovascular Concerns from COVID-19 in Pilots

BACKGROUND: Cardiovascular disease, now complicated by the COVID-19 pandemic, remains a leading cause of death and risk for sudden incapacitation for pilots during flight. The capacity for aeromedically significant cardiovascular sequelae with potentially imperceptible clinical symptoms elicits concern both during and following resolution of acute COVID-19 in pilots.OBJECTIVE: We summarize the current state of knowledge regarding COVID-19 cardiovascular implications as applied to the aviation environment to better understand their significance toward flight safety and application toward a focused cardiovascular screening protocol following recovery from infection.METHODS: A narrative review of the cardiovascular implications of COVID-19 infection was performed using the PubMed literature search engine and existing organizational guidelines. In addition, to established medical aviation benchmarks, surrogate populations examined included high performance athletes (as a correlate for high G-forces), and scuba divers (as an environmental work analog). Conditions of primary concern included myocardial injury, proarrhythmic substrates, risk of sudden death, myopericarditis, pulse orthostatic lability in response to vigorous activity, cardiovagal dysfunction, and thromboembolic disease.LITERATURE REVIEW: Cardiovascular screening guideline recommendations post-infection recovery are suggested based on profile stratification: airperson flight class, tactical military, and aerobatic pilots. This provides an approach to inform aeromedical decision making.CONCLUSION: Aviation medical examiners should remain cognizant of the clinically apparent and occult manifestations of cardiovascular dysfunction associated with COVID-19 infection when applying return-to-work screening guidelines. This will ensure high flight safety standards are maintained and sudden incapacitation risk mitigated during and following the ongoing pandemic.Elkhatib W, Herrigel D, Harrison M, Flipse T, Speicher L. Cardiovascular concerns from COVID-19 in pilots. Aerosp Med Hum Perform. 2022; 93(12):855-865.

A review and assessment of cyanobacterial toxins as cardiovascular health hazards

Eutrophicated waters frequently support bloom-forming cyanobacteria, many of which produce potent cyanobacterial toxins (cyanotoxins). Cyanotoxins can cause adverse health effects in a wide range of organisms where the toxins may target the liver, other internal organs, mucous surfaces and the skin and nervous system. This review surveyed more than 100 studies concerning the cardiovascular toxicity of cyanotoxins and related topics. Over 60 studies have described various negative effects on the cardiovascular system by seven major types of cyanotoxins, i.e. the microcystin (MC), nodularin (NOD), cylindrospermopsin (CYN), anatoxin (ATX), guanitoxin (GNTX), saxitoxin (STX) and lyngbyatoxin (LTX) groups. Much of the research was done on rodents and fish using high, acutely toxin concentrations and unnatural exposure routes (such as intraperitoneal injection), and it is thus concluded that the emphasis in future studies should be on oral, chronic exposure of mammalian species at environmentally relevant concentrations. It is also suggested that future in vivo studies are conducted in parallel with studies on cells and tissues. In the light of the presented evidence, it is likely that cyanotoxins do not constitute a major risk to cardiovascular health under ordinary conditions met in everyday life. The risk of illnesses in other organs, in particular the liver, is higher under the same exposure conditions. However, adverse cardiovascular effects can be expected due to indirect effects arising from damage in other organs. In addition to risks related to extraordinary concentrations of the cyanotoxins and atypical exposure routes, chronic exposure together with co-existing diseases could make some of the cyanotoxins more dangerous to cardiovascular health.

Melatonin: Regulation of Viral Phase Separation and Epitranscriptomics in Post-Acute Sequelae of COVID-19

The relentless, protracted evolution of the SARS-CoV-2 virus imposes tremendous pressure on herd immunity and demands versatile adaptations by the human host genome to counter transcriptomic and epitranscriptomic alterations associated with a wide range of short- and long-term manifestations during acute infection and post-acute recovery, respectively. To promote viral replication during active infection and viral persistence, the SARS-CoV-2 envelope protein regulates host cell microenvironment including pH and ion concentrations to maintain a high oxidative environment that supports template switching, causing extensive mitochondrial damage and activation of pro-inflammatory cytokine signaling cascades. Oxidative stress and mitochondrial distress induce dynamic changes to both the host and viral RNA m6A methylome, and can trigger the derepression of long interspersed nuclear element 1 (LINE1), resulting in global hypomethylation, epigenetic changes, and genomic instability. The timely application of melatonin during early infection enhances host innate antiviral immune responses by preventing the formation of "viral factories" by nucleocapsid liquid-liquid phase separation that effectively blockades viral genome transcription and packaging, the disassembly of stress granules, and the sequestration of DEAD-box RNA helicases, including DDX3X, vital to immune signaling. Melatonin prevents membrane depolarization and protects cristae morphology to suppress glycolysis via antioxidant-dependent and -independent mechanisms. By restraining the derepression of LINE1 via multifaceted strategies, and maintaining the balance in m6A RNA modifications, melatonin could be the quintessential ancient molecule that significantly influences the outcome of the constant struggle between virus and host to gain transcriptomic and epitranscriptomic dominance over the host genome during acute infection and PASC.

Vitamin D: A Role Also in Long COVID-19?

Coronavirus disease 2019 (COVID-19) has quickly become a global pandemic. Reports from different parts of the world indicate that a significant proportion of people who have recovered from COVID-19 are suffering from various health problems collectively referred to as “long COVID-19”. Common symptoms include fatigue, shortness of breath, cough, joint pain, chest pain, muscle aches, headaches, and so on. Vitamin D is an immunomodulatory hormone with proven efficacy against various upper respiratory tract infections. Vitamin D can inhibit hyperinflammatory reactions and accelerate the healing process in the affected areas, especially in lung tissue. Moreover, vitamin D deficiency has been associated with the severity and mortality of COVID-19 cases, with a high prevalence of hypovitaminosis D found in patients with COVID-19 and acute respiratory failure. Thus, there are promising reasons to promote research into the effects of vitamin D supplementation in COVID-19 patients. However, no studies to date have found that vitamin D affects post-COVID-19 symptoms or biomarkers. Based on this scenario, this review aims to provide an up-to-date overview of the potential role of vitamin D in long COVID-19 and of the current literature on this topic.

COVID-19-Associated Myocarditis: An Evolving Concern in Cardiology and Beyond

Simple Summary

Coronavirus disease-2019 (COVID-19) affects many organs in the body, including the heart. One complication of particular concern is inflammation of the heart muscle, called myocarditis. This paper presents updated research data on COVID-19-associated myocarditis. Specifically, we review the incidence, potential mechanisms, blood and imaging tests that can be used to detect the disease. We emphasize that, in contrast with early reports, recent data suggest that myocarditis in the setting of COVID-19 is relatively uncommon, yet infected individuals are at a substantially increased risk for poor outcomes. It is important to continue research in this area.

Abstract

The direct and indirect adverse effects of SARS-CoV-2 infection on the cardiovascular system, including myocarditis, are of paramount importance. These not only affect the disease course but also determine clinical outcomes and recovery. In this review, the authors aimed at providing an update on the incidence of Coronavirus disease-2019 (COVID-19)-associated myocarditis. Our knowledge and experience relevant to this area continues to evolve rapidly since the beginning of the pandemic. It is crucial for the scientific and medical community to stay abreast of current information. Contrasting early reports, recent data suggest that the overall incidence of SARS-CoV-2-associated myocarditis is relatively low, yet infected individuals are at a substantially increased risk. Therefore, understanding the pathophysiology and diagnostic evaluation, including the use of serum biomarkers and imaging modalities, remain important. This review aims to summarize the most recent data in these areas as they relate to COVID-19-associated myocarditis. Given its increasing relevance, a brief update is included on the proposed mechanisms of myocarditis in COVID-19 vaccine recipients.