Overview of the Pathogenesis and Treatment of SARS-CoV-2 for Clinicians: A Comprehensive Literature Review

Differentiating Leukostasis From COVID-19 Pneumonia: Clinical and Radiological Perspectives for the Right Decision-Making

Leukostasis is a non-infectious complication of acute leukemia. Pathophysiologically, it is characterized by an accumulation of blasts in the pulmonary capillaries. Clinically, this syndrome of hyperleukocytosis or leucocytosis leads to pulmonary and/or neurological lesions. This is why it must be treated urgently to prevent it from progressing to acute respiratory distress. In 2020, the World Health Organization (WHO) declared a pandemic caused by a novel coronavirus called SARS-CoV-2, which may cause respiratory distress or other clinical, biological, and radiological signs that some may confuse with those of leukostasis. In this context, we present a compelling case study of a 64-year-old patient with no notable pathological antecedents and not vaccinated against COVID-19, who presented with acute respiratory distress. The purpose of our article is to succeed in differentiating between the two pneumopathies, thus making it possible to orient the doctor toward the right decision-making. As known, early recognition enables timely interventions, reducing disease progression and associated complications while also preventing unnecessary treatments, optimizing healthcare resources, and advancing medical knowledge for improved patient care in both acute leukemia and COVID-19 management.

The bidirectional relationship between fatty liver disease and COVID-19

COVID-19 and nonalcoholic fatty liver disease (NAFLD) have emerged as global pandemics affecting millions of people worldwide over the past three years. NAFLD is particularly prevalent in individuals with metabolic comorbidities, such as diabetes and obesity, which have been strongly linked to a severe course of Sars-CoV-2 infection. Recently, due to the close association between metabolic abnormalities and NAFLD, the disease has been redefined as metabolic dysfunction-associated fatty liver disease (MAFLD). This review offers an overview of the biological and cellular mechanisms by which COVID-19 can cause liver damage, with a specific focus on the influence of fatty liver in these mechanisms. Additionally, it explores how fatty liver can exacerbate a COVID-19 infection and, conversely, if the presence of COVID-19 may accelerate the development and progression of fatty liver. Finally, the review examines the existing evidence suggesting that NAFLD or MAFLD independently contributes to a heightened severity of COVID-19, while also considering other factors such as age and metabolic comorbidities that may play a role in the disease’s progression.

Proteomic Analysis Identifies Molecular Players and Biological Processes Specific to SARS-CoV-2 Exposure in Endothelial Cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for the severe pandemic of acute respiratory disease, coronavirus disease 2019 (COVID-19), experienced in the 21st century. The clinical manifestations range from mild symptoms to abnormal blood coagulation and severe respiratory failure. In severe cases, COVID-19 manifests as a thromboinflammatory disease. Damage to the vascular compartment caused by SARS-CoV-2 has been linked to thrombosis, triggered by an enhanced immune response. The molecular mechanisms underlying endothelial activation have not been fully elucidated. We aimed to identify the proteins correlated to the molecular response of human umbilical vein endothelial cells (HUVECs) after exposure to SARS-CoV-2, which might help to unravel the molecular mechanisms of endothelium activation in COVID-19. In this direction, we exposed HUVECs to SARS-CoV-2 and analyzed the expression of specific cellular receptors, and changes in the proteome of HUVECs at different time points. We identified that HUVECs exhibit non-productive infection without cytopathic effects, in addition to the lack of expression of specific cell receptors known to be essential for SARS-CoV-2 entry into cells. We highlighted the enrichment of the protein SUMOylation pathway and the increase in SUMO2, which was confirmed by orthogonal assays. In conclusion, proteomic analysis revealed that the exposure to SARS-CoV-2 induced oxidative stress and changes in protein abundance and pathways enrichment that resembled endothelial dysfunction.

Vaccine efficacy in mutant SARS-CoV-2 variants

Many aspects of the SARS-CoV-2 virus remain poorly understood, including its rapid mutation and its effects on populations of different ages. The present literature of review is focused on the effectiveness of current available vaccines in view of immerging several SARS-CoV-2 variants. The most dangerous and infectious SARS-CoV-2 strain, B117, was recently discovered in the United Kingdom, and another new variant, 501.V2, was discovered in South Africa. In countries such as the United States, Japan, India, and Brazil, the variant B117 spread far more quickly than the original strain. The new SARS-CoV-2 mutations have made producing a universal and effective vaccine more difficult. SARS-CoV-2's S protein, which aids in receptor identification and membrane fusion, is a primary target for vaccine development using its mRNA or inactivated virus. Currently, in the interval of few days new more infectious SARS-CoV-2 mutant is detected, started from SARS-CoV-2 Alpha (B.1.1.7), beta (B.1.351), delta (B.1.617.2), delta plus, gamma (P.1) and now variant lamda. The variant detected first in Peru and spread almost 27 countries including UK that accounts for 82% of new infections. These mutant variants are posing new challenge even to the fully vaccinated individuals and a challenge for the public health. Thus, a need to review current treatment vaccination guideline and strategy as early as possible. Reporting all new SARS-CoV-2 variants and their effectiveness in response to several available vaccines, we would like to draw the attention of health care provider, and all developed countries health care agencies including WHO to frame new guidelines for vaccination and immediate intervention to control the development of new SARS-CoV-2 variants from the third world countries by providing vaccines to the poor countries as early as possible.

Pathophysiological mechanisms underlying gastrointestinal symptoms in patients with COVID-19

Gastrointestinal (GI) symptoms, such as diarrhea, abdominal pain, vomiting, and anorexia, are frequently observed in patients with coronavirus disease 2019 (COVID-19). However, the pathophysiological mechanisms connecting these GI symptoms to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections remain elusive. Previous studies indicate that the entry of SARS-CoV-2 into intestinal cells leads to downregulation of angiotensin converting enzyme 2 (ACE2) receptors resulting in impaired barrier function. While intestinal ACE2 functions as a chaperone for the amino acid transporter B0AT1, the B0AT1/ACE2 complex within the intestinal epithelium acts as a regulator of gut microbiota composition and function. Alternations to the B0AT1/ACE2 complex lead to microbial dysbiosis through increased local and systemic immune responses. Previous studies have also suggested that altered serotonin metabolism may be the underlying cause of GI disorders involving diarrhea. The findings of elevated plasma serotonin levels and high fecal calprotectin in COVID-19 patients with diarrhea indicate that the viral infection evokes a systemic inflammatory response that specifically involves the GI. Interestingly, the elevated proinflammatory cytokines correlate with elevated serotonin and fecal calprotectin levels further supporting the evidence of GI inflammation, a hallmark of functional GI disorders. Moreover, the finding that rectal swabs of COVID-19 patients remain positive for SARS-CoV-2 even after the nasopharynx clears the virus, suggests that viral replication and shedding from the GI tract may be more robust than that of the respiratory tract, further indicating fecal-oral transmission as another important route of viral spread. This review summarized the evidence for pathophysiological mechanisms (impaired barrier function, gut inflammation, altered serotonin metabolism and gut microbiota dysbiosis) underlying the GI symptoms in patients with COVID-19.

COVID-19: Virology, biology and novel laboratory diagnosis

BACKGROUND

At the end of December 2019, a novel coronavirus tentatively named SARS-CoV-2 in Wuhan, a central city in China, was announced by the World Health Organization. SARS-CoV-2 is an RNA virus that has become a major public health concern after the outbreak of the Middle East Respiratory Syndrome-CoV (MERS-CoV) and Severe Acute Respiratory Syndrome-CoV (SARS-CoV) in 2002 and 2012, respectively. As of 29 October 2020, the total number of COVID-19 cases had reached over 44 million worldwide, with more than 1.17 million confirmed deaths.

DISCUSSION

SARS-CoV-2 infected patients usually present with severe viral pneumonia. Similar to SARS-CoV, the virus enters respiratory tract cells via the angiotensin-converting enzyme receptor 2. The structural proteins play an essential role in budding the virus particles released from different host cells. To date, an approved vaccine or treatment option of a preventive character to avoid severe courses of COVID-19 is still not available.

CONCLUSIONS

In the present study, we provide a brief review of the general biological features of CoVs and explain the pathogenesis, clinical symptoms and diagnostic approaches regarding monitoring future infectivity and prevent emerging COVID-19 infections.