COVID 19 and liver: An A-Z literature review

Pathophysiology of infection with SARS-CoV-2-What is known and what remains a mystery

Coronavirus disease 2019 (COVID‐19), caused by coronavirus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has caused extensive disruption and mortality since its recent emergence. Concomitantly, there has been a race to understand the virus and its pathophysiology. The clinical manifestations of COVID‐19 are manifold and not restricted to the respiratory tract. Extrapulmonary manifestations involving the gastrointestinal tract, hepatobiliary system, cardiovascular and renal systems have been widely reported. However, the pathophysiology of many of these manifestations is controversial with questionable support for direct viral invasion and an abundance of alternative explanations such as pre‐existing medical conditions and critical illness. Prior research on SARS‐Co‐V and NL63 was rapidly leveraged to identify angiotensin‐converting enzyme 2 (ACE2) receptor as the key cell surface receptor for SARS‐CoV‐2. The distribution of ACE2 has been used as a starting point for estimating vulnerability of various tissue types to SARS‐CoV‐2 infection. Sophisticated organoid and animal models have been used to demonstrate such infectivity of extrapulmonary tissues in vitro, but the clinical relevance of these findings remains uncertain. Clinical autopsy studies are typically small and inevitably biased towards patients with severe COVID‐19 and prolonged hospitalization. Technical issues such as delay between time of death and autopsy, use of inappropriate antibodies for paraffin‐embedded tissue sections and misinterpretation of cellular structures as virus particles on electron micrograph images are additional problems encountered in the extant literature. Given that SARS‐CoV‐2 is likely to circulate permanently in human populations, there is no doubt that further work is required to clarify the pathobiology of COVID‐19.

Patients with cirrhosis during the COVID-19 pandemic: Current evidence and future perspectives

The outbreak of coronavirus disease-2019 (COVID-19) has resulted in a global public health emergency. Patients with cirrhosis were deemed more susceptible to viral infection because of their dysregulated immune response. Similar to the general population, cirrhotic patients exhibit various degrees of COVID-19-related liver injury, which could be attributed to direct virus cytotoxicity, systemic immune system activation, drug-related liver injury, reactivation of pre-existing liver disease, and hypoxic hepatitis. The clinical symptoms in patients with cirrhosis and COVID-19 were similar to those in the general population with COVID-19, with a lower proportion of patients with gastrointestinal symptoms. Although respiratory failure is the predominant cause of mortality in cirrhotic patients with COVID-19, a significant proportion of them lack initial respiratory symptoms. Most evidence has shown that cirrhotic patients have relatively higher rates of morbidity and mortality associated with COVID-19. Advanced cirrhosis was also proposed as an independent factor affecting a poor prognosis and the need to consider COVID-19 palliative care. General measures implemented to prevent the transmission of the virus are also essential for cirrhotic patients, and they should also receive standard cirrhosis care with minimal interruptions. The efficacy of the available COVID-19 vaccines in cirrhotic patients still needs investigation.

Impact of cytokine storm and systemic inflammation on liver impairment patients infected by SARS-CoV-2: Prospective therapeutic challenges

Coronavirus disease 2019 (COVID-19) is a devastating worldwide pandemic infection caused by a severe acute respiratory syndrome namely coronavirus 2 (SARS-CoV-2) that is associated with a high spreading and mortality rate. On the date this review was written, SARS-CoV-2 infected about 96 million people and killed about 2 million people. Several arguments disclosed the high mortality of COVID-19 due to acute respiratory distress syndrome or change in the amount of angiotensin-converting enzyme 2 (ACE2) receptor expression or cytokine storm strength production. In a similar pattern, hepatic impairment patients co-infected with SARS-CoV-2 exhibited overexpression of ACE2 receptors and cytokine storm overwhelming, which worsens the hepatic impairment and increases the mortality rate. In this review, the impact of SARS-CoV-2 on hepatic impairment conditions we overviewed. Besides, we focused on the recent studies that indicated cytokine storm as well as ACE2 as the main factors for high COVID-19 spreading and mortality while hinting at the potential therapeutic strategies.

Assessment of liver damage in patients with COVID-19 is sub-optimal: results of a survey of medical practitioners

Liver damage, defined by an increase in liver biochemical parameters, is related to a more unfavorable severity and prognosis in patients with COVID-19. These patients are also treated with immunomodulatory drugs capable of reactivating the hepatitis B virus (HBV), with indication for prophylaxis in specific situations. Due to its importance in this pathology, we wondered whether physicians should perform a systematic search for liver damage and HBV.

COVID-19 and the liver: an adverse outcome pathway perspective

Liver damage is observed in up to half of hospitalized COVID-19 patients and can result either from actions of SARS-CoV-2 as such or from pharmacological treatment. The present paper introduces an adverse outcome pathway construct that mechanistically describes the pathways induced by SARS-CoV-2 leading to liver injury. This can be caused by direct binding of the virus and local actions in cholangiocytes, but may also indirectly result from the general state of hypoxia and systemic inflammation in COVID-19 patients. Further research is urgently needed to fill remaining knowledge gaps. This will be anticipated to create a solid basis for future and more targeted development of vaccines and, in particular, therapies.

A novel multi-omics-based highly accurate prediction of symptoms, comorbid conditions, and possible long-term complications of COVID-19

Comprehensive clinical pictures, comorbid conditions, and long-term complications of COVID-19 are still unknown. Recently, using a multi-omics-based strategy, we predicted potential drugs for COVID-19 with ∼70% accuracy. Herein, using a novel multi-omics-based bioinformatic approach and three ways of analysis, we identified the symptoms, comorbid conditions, and short-, mid-, and possible long-term complications of COVID-19 with >90% precision including 27 parent, 170 child, and 403 specific conditions. Among the specific conditions, 36 viral, 53 short-term, 62 short-mid-long-term, 194 mid-long-term, and 57 congenital conditions are identified. At a threshold "count of occurrence" of 4, we found that 83-100% (average 92.67%) of enriched conditions are associated with COVID-19. Except for dry cough and loss of taste, all the other COVID-19-associated mild and severe symptoms are enriched. CVDs, and pulmonary, metabolic, musculoskeletal, neuropsychiatric, kidney, liver, and immune system disorders are top comorbid conditions. Specific diseases like myocardial infarction, hypertension, COPD, lung injury, diabetes, cirrhosis, mood disorders, dementia, macular degeneration, chronic kidney disease, lupus, arthritis, etc. along with several other NCDs were found to be top candidates. Interestingly, many cancers and congenital disorders associated with COVID-19 severity are also identified. Arthritis, gliomas, diabetes, psychiatric disorders, and CVDs having a bidirectional relationship with COVID-19 are also identified as top conditions. Based on our accuracy (>90%), the long-term presence of SARS-CoV-2 RNA in human, and our "genetic remittance" assumption, we hypothesize that all the identified top-ranked conditions could be potential long-term consequences in COVID-19 survivors, warranting long-term observational studies.

Liver injury in the era of COVID-19

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has undoubtedly revolutionized the whole globe and given a new point of view on respiratory tract infections. Nevertheless, coronavirus disease 2019 (COVID-19) cannot be perceived as a disease limited only to pneumonia with diverse severity. More and more reports have demonstrated a wide range of possible systemic symptoms, including hepatic complications. Liver injury has been observed in a significant proportion of patients, especially in those with a severe or critical illness. COVID-19 might provoke a deterioration of liver function in patients with already diagnosed chronic liver diseases and without pre-existing liver disorders. The deterioration of liver function worsens the prognosis, increases the risk of a severe course of SARS-CoV-2 infection and prolongs the hospital stay. In general, patients who develop liver dysfunction in COVID-19 are mainly males, elderly people, and those with higher body mass index. The underlying mechanisms for hepatic failure in patients infected with SARS-CoV-2 are still unclear, nevertheless liver damage appears to be directly connected with virus-induced cytopathic effects. A liver injury observed during hospitalization might be simultaneously caused by the use of potentially hepatotoxic drugs, mainly antiviral agents. This minireview focuses on a possible relationship between COVID-19 and the liver, potential molecular mechanisms of liver damage, the characteristics of liver injury and suggested factors predisposing to hepatic manifestations in COVID-19 patients.

Body Localization of ACE-2: On the Trail of the Keyhole of SARS-CoV-2

The explosion of the new coronavirus (SARS-CoV-2) pandemic has brought the role of the angiotensin converting enzyme 2 (ACE2) back into the scientific limelight. Since SARS-CoV-2 must bind the ACE2 for entering the host cells in humans, its expression and body localization are critical to track the potential target organ of this infection and to outline disease progression and clinical outcomes. Here, we mapped the physiological body distribution, expression, and activities of ACE2 and discussed its potential correlations and mutal interactions with the disparate symptoms present in SARS-CoV-2 patients at the level of different organs. We highlighted that despite during SARS-CoV-2 infection ACE2-expressing organs may become direct targets, leading to severe pathological manifestations, and subsequent multiple organ failures, the exact mechanism and the potential interactions through which ACE2 acts in these organs is still heavily debated. Further scientific efforts, also considering a personalized approach aimed to consider specific patient differences in the mutual interactions ACE2-SARS-CoV-2 and the long-term health effects associated with COVID-19 are currently mandatory.