Findings of Hepatic Severe Acute Respiratory Syndrome Coronavirus-2 Infection

Impact of liver fibrosis on COVID-19 in-hospital mortality in Southern Italy

BACKGROUND & AIMS

SARS-Cov-2 infection manifests as a wide spectrum of clinical presentation and even now, despite the global spread of the vaccine, contagiousness is still elevated. The aim of the study was the evaluation of the impact of liver fibrosis assessed by FIB-4 and liver impairment, assessed by cytolysis indices, on intrahospital mortality in COVID-19 subjects.

METHODS

This is a retrospective observational cohort study, which involved 23 COVID Hospital Units in Campania Region, Italy. Exposure variables were collected during hospital admission and at discharge. According to FIB-4 values, we subdivided the overall population in three groups (FIB-4<1.45; 1.453.25), respectively group 1,2,3.

RESULTS

At the end of the study, 938 individuals had complete discharged/dead data. At admission, 428 patients were in group 1 (45.6%), 387 in group 2 (41.3%) and 123 in group 3 (13.1%). Among them, 758 (81%) subjects were discharged, while the remaining 180 (19%) individuals died. Multivariable Cox's regression model showed a significant association between mortality risk and severity of FIB-4 stages (group 3 vs group 1, HR 2.12, 95%CI 1.38-3.28, p<0.001). Moreover, Kaplan-Meier analysis described a progressive and statistically significant difference (p<0.001 Log-rank test) in mortality according to FIB-4 groups. Among discharged subjects, 507 showed a FIB-4<1.45 (66.9%, group 1), 182 a value 1.453.25 (9.0%, group 3). Among dead subjects, 42 showed a FIB-4<1.45 (23.3%, group 1), 62 a value 1.453.25 (42.3%, group 3).

CONCLUSIONS

FIB-4 value is significantly associated with intrahospital mortality of COVID-19 patients. During hospitalization, particularly in patients with worse outcomes, COVID-19 seems to increase the risk of acute progression of liver damage.

Host determinants and responses underlying SARS-CoV-2 liver tropism

Hepatic sequelae are frequently reported in coronavirus disease 2019 cases and are correlated with increased disease severity. Therefore, a detailed exploration of host factors contributing to hepatic impairment and ultimately infection outcomes in patients is essential for improved clinical management. The causes of hepatic injury are not limited to drug-mediated toxicity or aberrant host inflammatory responses. Indeed, multiple studies report the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in liver autopsies and the susceptibility of explanted human hepatocytes to infection. In this review, we confirm that hepatic cells express an extensive range of factors implicated in SARS-CoV-2 entry. We also provide an overview of studies reporting evidence for direct infection of liver cell types and the infection-induced cell-intrinsic processes that likely contribute to hepatic impairment.

Current remarks and future directions on the interactions between metabolic dysfunction-associated fatty liver disease and COVID-19

During the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, particular interest rose regarding the interaction between metabolic dysfunction-associated fatty liver disease (MAFLD) and the COVID-19 infection. Several studies highlighted the fact that individuals with MAFLD had higher probability of severe acute respiratory syndrome coronavirus 2 infection and more severe adverse clinical outcomes. One of the proposed mechanisms is the inflammatory response pathway, especially the one involving cytokines, such as interleukin 6, which appeared particularly elevated in those patients and was deemed responsible for additional insult to the already damaged liver. This should increase our vigilance in terms of early detection, close follow up and early treatment for individuals with MAFLD and COVID-19 infection. In the direction of early diagnosis, biomarkers such as cytokeratin-18 and scoring systems such as Fibrosis-4 index score are proposed. COVID-19 is a newly described entity, expected to be of concern for the years to come, and MAFLD is a condition with an ever-increasing impact. Delineating the interaction between these two entities should be brought into the focus of research. Reducing morbidity and mortality of patients with COVID-19 and MAFLD should be the ultimate objective, and the optimal way to achieve this is by designing evidence-based prevention and treatment policies.

Diabetes Mellitus, Energy Metabolism, and COVID-19

Obesity, diabetes mellitus (mostly type 2), and COVID-19 show mutual interactions because they are not only risk factors for both acute and chronic COVID-19 manifestations, but also because COVID-19 alters energy metabolism. Such metabolic alterations can lead to dysglycemia and long-lasting effects. Thus, the COVID-19 pandemic has the potential for a further rise of the diabetes pandemic. This review outlines how preexisting metabolic alterations spanning from excess visceral adipose tissue to hyperglycemia and overt diabetes may exacerbate COVID-19 severity. We also summarize the different effects of SARS-CoV-2 infection on the key organs and tissues orchestrating energy metabolism, including adipose tissue, liver, skeletal muscle, and pancreas. Last, we provide an integrative view of the metabolic derangements that occur during COVID-19. Altogether, this review allows for better understanding of the metabolic derangements occurring when a fire starts from a small flame, and thereby help reducing the impact of the COVID-19 pandemic.

Liver biopsy for assessment of suspected drug-induced liver injury in metabolic dysfunction-associated steatohepatitis clinical trials: Expert consensus from the Liver Forum

BACKGROUND

Causality assessment of suspected drug-induced liver injury (DILI) during metabolic dysfunction-associated steatohepatitis (MASH) clinical trials can be challenging, and liver biopsies are not routinely performed as part of this evaluation. While the field is moving away from liver biopsy as a diagnostic and prognostic tool, information not identified by non-invasive testing may be provided on histology.

AIM

To address the appropriate utilisation of liver biopsy as part of DILI causality assessment in this setting.

METHODS

From 2020 to 2022, the Liver Forum convened a series of webinars on issues pertaining to liver biopsy during MASH trials. The Histology Working Group was formed to generate a series of consensus documents addressing these challenges. This manuscript focuses on liver biopsy as part of DILI causality assessment.

RESULTS

Expert opinion, guidance and recommendations on the role of liver biopsy as part of causality assessment of suspected DILI occurring during clinical trials for a drug(s) being developed for MASH are provided. Lessons learned from prior MASH programs are reviewed and gaps identified.

CONCLUSIONS

Although there are no pathognomonic features, histologic evaluation of suspected DILI during MASH clinical trials may alter patient management, define the pattern and severity of injury, detect findings that favour a diagnosis of DILI versus MASH progression, identify prognostic features, characterise the clinicopathological phenotype of DILI, and/or define lesions that influence decisions about trial discontinuation and further development of the drug.

Elevated Levels of Cytotoxicity, Cytokines, and Anti-SARS-CoV-2 Antibodies in Mild Cases of COVID-19

Current evidence shows higher production of cytokines and antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in severe and critical cases of Coronavirus Disease 2019 (COVID-19) in comparison with patients with moderate or mild disease. A recent hypothesis proposes an important role of genotoxicity and cytotoxicity in the induction of the cytokine storm observed in some patients at later stages of the disease. Interestingly, in this study, we report significantly higher levels of interleukin (IL)-1β, IL-6, MCP-1, and IL-4 cytokines in mild COVID-19 patients versus severe cases, as well as a high frequency of karyorrhexis (median [Me] = 364 vs. 20 cells) and karyolysis (Me = 266 vs. 52 cells) in the mucosal epithelial cells of both groups of patients compared with uninfected individuals. Although we observed higher levels of anti-SARS-CoV-2 IgM and IgG antibodies in COVID-19 patients, IgM antibodies were significantly higher only in mild cases, for the N and the S viral antigens. High levels of IgG antibodies were observed in both mild and severe cases. Our results showed elevated concentrations of proinflammatory and anti-inflammatory cytokines in mild cases, which may reflect an active innate immune response and could be related to the higher IgM and IgG antibody levels found in those patients. In addition, we found that SARS-CoV-2 infection induces cytotoxic damage in the oral mucosa, highlighting the importance of studying the genotoxic and cytotoxic events induced by infection and its role in the pathophysiology of COVID-19.

Systemic Disease and the Liver-Part 1: Systemic Lupus Erythematosus, Celiac Disease, Rheumatoid Arthritis, and COVID-19

The development of liver dysfunction in patients having various systemic diseases is common and has a broad differential diagnosis, at times being the initial manifestation of the disorder. Liver injury associated with systemic lupus erythematosus is heterogeneous and may present with nonspecific histology. Differentiating autoimmune hepatitis from lupus hepatitis is challenging on histologic grounds alone. Other systemic diseases that may present mostly with nonspecific findings are rheumatoid arthritis and celiac disease. More recently COVID-19 cholangiopathy and secondary sclerosing cholangitis have become increasingly recognized as distinct liver conditions. Many patients may also have intrinsic liver disease or may develop drug-induced liver injury from the treatment of the systemic disease. Timely identification of the cause of the liver dysfunction is essential and liver biopsy may help the clinician in diagnosis and management.

SARS-CoV-2 induced liver injury: Incidence, risk factors, impact on COVID-19 severity and prognosis in different population groups

Liver is unlikely the key organ driving mortality in coronavirus disease 2019 (COVID-19) however, liver function tests (LFTs) abnormalities are widely observed mostly in moderate and severe cases. According to this review, the overall prevalence of abnormal LFTs in COVID-19 patients ranges from 2.5% to 96.8% worldwide. The geographical variability in the prevalence of underlying diseases is the determinant for the observed discrepancies between East and West. Multifactorial mechanisms are implicated in COVID-19-induced liver injury. Among them, hypercytokinemia with "bystander hepatitis", cytokine storm syndrome with subsequent oxidative stress and endotheliopathy, hypercoagulable state and immuno-thromboinflammation are the most determinant mechanisms leading to tissue injury. Liver hypoxia may also contribute under specific conditions, while direct hepatocyte injury is an emerging mechanism. Except for initially observed severe acute respiratory distress syndrome corona virus-2 (SARS-CoV-2) tropism for cholangiocytes, more recent cumulative data show SARS-CoV-2 virions within hepatocytes and sinusoidal endothelial cells using electron microscopy (EM). The best evidence for hepatocellular invasion by the virus is the identification of replicating SARS-CoV-2 RNA, S protein RNA and viral nucleocapsid protein within hepatocytes using in-situ hybridization and immunostaining with observed intrahepatic presence of SARS-CoV-2 by EM and by in-situ hybridization. New data mostly derived from imaging findings indicate possible long-term sequelae for the liver months after recovery, suggesting a post-COVID-19 persistent live injury.

The Spectrum of Digestive Tract Histopathologic Findings in the Setting of Severe Acute Respiratory Syndrome Coronavirus-2 Infection: What Pathologists Need to Know

Although the novel severe acute respiratory syndrome coronavirus-2 is known primarily to affect the respiratory system, current evidence supports its capability to infect and induce gastrointestinal tract injury. Data describing the histopathologic alterations of the digestive system in patients infected with severe acute respiratory syndrome coronavirus-2 are becoming more detailed, as the number of studies is increasing and the quality of our insight into the infection and the histopathologic findings is improving. This review highlights the range of pathologic findings that could be observed in gastrointestinal specimens from patients infected with coronavirus disease 2019 and the potential underlying pathogenetic mechanisms of this disease.

Liver Injury Associated with COVID-19 Infection: Pathogenesis, Histopathology, Prognosis, and Treatment

Liver injury occurs frequently as a consequence of SARS-CoV-2 infection. Direct infection of the liver leads to hepatic impairment with elevated transaminases. In addition, severe COVID-19 is characterized by cytokine release syndrome, which may initiate or exacerbate liver injury. In patients with cirrhosis, SARS-CoV-2 infection is associated with acute-on-chronic liver failure. The Middle East and North Africa (MENA) region is one of the world's regions characterized by a high prevalence of chronic liver diseases. Both parenchymal and vascular types of injury contribute to liver failure in COVID-19, with a myriad of pro-inflammatory cytokines playing a major role in perpetuating liver injury. Additionally, hypoxia and coagulopathy complicate such a condition. This review discusses the risk factors, and the underlying causes of impaired liver functions in COVID-19, with a focus on key players in the pathogenesis of liver injury. It also highlights the histopathological changes encountered in postmortem liver tissues as well as potential predictors and prognostic factors of such injury, in addition to the management strategies to ameliorate liver damage.

Pathologic Characteristics of Digestive Tract and Liver in Patients with Coronavirus Disease 2019

With the high prevalence of coronavirus disease-2019 (COVID-19), there has been increasing understanding of the pathologic changes associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This review summarizes the pathologic changes in the digestive system and liver associated with COVID-19, including the injuries induced by SARS-CoV2 infection of GI epithelial cells and the systemic immune responses. The common digestive manifestations associated with COVID-19 include anorexia, nausea, vomiting, and diarrhea; the clearance of the viruses in COVID-19 patients with digestive symptoms is usually delayed. COVID-19-associated gastrointestinal histopathology is characterized by mucosal damage and lymphocytic infiltration. The most common hepatic changes are steatosis, mild lobular and portal inflammation, congestion/sinusoidal dilatation, lobular necrosis, and cholestasis.

COVID-19: gastrointestinal and hepatobiliary manifestations

SARS-CoV-2 is the viral agent of COVID-19, a pandemic that surfaced in 2019. Although predominantly a respiratory ailment, patients with COVID-19 can have gastrointestinal (GI) and hepatobiliary manifestations. These manifestations are often mild and transient, but they can be severe and consequential. In the GI tract, ischemic enterocolitis is the most common and significant consequence of COVID-19. In the liver, the reported pathologic findings may often be related to consequences of severe systemic viral infection, but reports of hepatitis presumed to be due to SARS-CoV-2 suggest that direct viral infection of the liver may be a rare complication of COVID-19. In both the GI tract and liver, lingering symptoms of GI or hepatic injury after resolution of pulmonary infection may be part of the evolving spectrum of long COVID.

COVID-19 and hepatic injury: cellular and molecular mechanisms in diverse liver cells

The coronavirus disease 2019 (COVID-19) represents a global health and economic challenge. Hepatic injuries have been approved to be associated with severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection. The viral tropism pattern of SARS-CoV-2 can induce hepatic injuries either by itself or by worsening the conditions of patients with hepatic diseases. Besides, other factors have been reported to play a crucial role in the pathological forms of hepatic injuries induced by SARS-CoV-2, including cytokine storm, hypoxia, endothelial cells, and even some treatments for COVID-19. On the other hand, several groups of people could be at risk of hepatic COVID-19 complications, such as pregnant women and neonates. The present review outlines and discusses the interplay between SARS-CoV-2 infection and hepatic injury, hepatic illness comorbidity, and risk factors. Besides, it is focused on the vaccination process and the role of developed vaccines in preventing hepatic injuries due to SARS-CoV-2 infection.

Liver pathology in COVID-19 related death and leading role of autopsy in the pandemic

BACKGROUND

Information on liver involvement in patients with coronavirus disease 2019 is currently fragmented.

AIM

To highlight the pathological changes found during the autopsy of severe acute respiratory syndrome coronavirus 2 positive patients.

METHODS

A systematic literature search on PubMed was carried out until June 21, 2022.

RESULTS

A literature review reveals that pre-existing liver disease and elevation of liver enzyme in these patients are not common; liver enzyme elevations tend to be seen in those in critical conditions. Despite the poor expression of viral receptors in the liver, it seems that the virus is able to infect this organ and therefore cause liver damage. Unfortunately, to date, the search for the virus inside the liver is not frequent (16% of the cases) and only a small number show the presence of the virus. In most of the autopsy cases, macroscopic assessment is lacking, while microscopic evaluation of livers has revealed the frequent presence of congestion (42.7%) and steatosis (41.6%). Less frequent is the finding of hepatic inflammation or necrosis (19%) and portal inflammation (18%). The presence of microthrombi, frequently found in the lungs, is infrequent in the liver, with only 12% of cases presenting thrombotic formations within the vascular tree.

CONCLUSION

To date, the greatest problem in interpreting these modifications remains the association of the damage with the direct action of the virus, rather than with the inflammation or alterations induced by hypoxia and hypovolemia in patients undergoing oxygen therapy and decompensated patients.

Liver injury in COVID-19: A minireview

Coronavirus disease 2019 (COVID-19), caused by infection with the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has escalated into a global tragedy afflicting human health, life, and social governance. Through the increasing depth of research and a better understanding of this disease, it has been ascertained that, in addition to the lungs, SARS-CoV-2 can also induce injuries to other organs including the liver. Liver injury is a common clinical manifestation of COVID-19, particularly in severe cases, and is often associated with a poorer prognosis and higher severity of COVID-19. This review focuses on the general existing information on liver injury caused by COVID-19, including risk factors and subpopulations of liver injury in COVID-19, the association between preexisting liver diseases and the severity of COVID-19, and the potential mechanisms by which SARS-CoV-2 affects the liver. This review may provide some useful information for the development of therapeutic and preventive strategies for COVID-19-associated liver injury.

COVID-19 associated liver injury: A general review with special consideration of pregnancy and obstetric outcomes

Liver injury is an increasingly recognized extra-pulmonary manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Coronavirus disease 2019 (COVID-19) associated liver injury (COVALI) is a clinical syndrome encompassing all patients with biochemical liver injury identified in the setting of SARS-CoV-2 infection. Despite profound clinical implications, its pathophysiology is poorly understood. Unfortunately, most information on COVALI is derived from the general population and may not be applicable to individuals under-represented in research, including pregnant individuals. This manuscript reviews: Clinical features of COVALI, leading theories of COVALI, and existing literature on COVALI during pregnancy, a topic not widely explored in the literature. Ultimately, we synthesized data from the general and perinatal populations that demonstrates COVALI to be a hepatocellular transaminitis that is likely induced by systemic inflammation and that is strongly associated with disease severity and poorer clinical outcome, and offered perspective on approaching transaminitis in the potentially COVID-19 positive patient in the obstetric setting.

Direct, indirect, post-infection damages induced by coronavirus in the human body: an overview

Background

Severe acute respiratory syndrome Coronavirus-2 invades the cells via ACE2 receptor and damages multiple organs of the human body. Understanding the pathological manifestation is mandatory to endure the rising post-infection sequel reported in patients with or without comorbidities.

Materials and methods

Our descriptive review emphasises the direct, indirect and post-infection damages due to COVID-19. We have performed an electronic database search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines with selective inclusion and exclusion criteria.

Results

The included studies substantiated the extensive damages in the multiple organs due to direct and indirect consequences of COVID-19. After an apparent recovery, the prolonged presentation of the symptoms manifests as post-COVID that can be related with persisting viral antigens and dysregulated immune response.

Conclusion

A few of the symptoms of respiratory, cardiovascular, and neuropsychiatric systems that persist or reappear as post-COVID manifestations. Vaccination and preventive programs will effectively reduce the prevalence but, the post-COVID, a multisystem manifestation, will be a significant tribulation to the medical profession. However, the issue can be managed by implementing public health programs, rehabilitation services, and telemedicine virtual supports to raise awareness and reduce panic.

SARS-CoV-2 infection of human pluripotent stem cell-derived liver organoids reveals potential mechanisms of liver pathology

Although respiratory symptoms are the most prevalent disease manifestation of infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), infection can also damage other organs, including the brain, gut, and liver. Symptoms of liver damage are observed in nearly half of patients that succumb to severe SARS-CoV-2 infection. Here we use human-induced pluripotent stem cell-derived liver organoids (HLOs) to recapitulate and characterize liver pathology following virus exposure. Utilizing single-cell sequencing technology, we identified robust transcriptomic changes that occur in SARS-CoV-2 infected liver cells as well as uninfected bystander cells. Our results show a significant induction of many inflammatory pathways, including IFN-α, INF-γ, and IL-6 signaling. Our results further identify IL-6 signaling as a potential mechanism for liver-mediated activation of circulating macrophages.

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Stem cell-derived liver organoids (HLOs) are susceptible to SARS-CoV-2 infection

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Within HLOs, hepatocyte-like cells mount the strongest inflammatory response

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Co-culture of HLOs with macrophages increases the inflammatory response to infection

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Infected HLOs secrete IL-6 which promotes macrophage expression of MCP-1

Potential histopathological and immunological effects of SARS-CoV-2 on the liver

The coronavirus disease outbreak of 2019 (COVID-19) poses a serious threat to public health worldwide. Lung injury is the most common complication of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. However, other organs, including the liver, can also be affected. Currently, there is limited evidence that liver impairment is associated with severe SARS-CoV-2 infection. Clinicians will need to determine whether liver injury is caused by an underlying liver condition, COVID-19 therapy, the virus directly, or immune-mediated inflammation or represents a complicated disease course in the context of COVID-19. To address the scarcity of data on histopathological changes and immunological effects on the liver with COVID-19 positivity, we analyze and summarize recent findings. We searched PubMed, Medline, Google Scholar, Science Direct, Scopus, and Web of Science databases up to December 1, 2021, identifying published studies with the search terms "Histopathology in COVID-19," "COVID-19," "Pathological changes in liver in COVID-19," "Liver pathology in COVID-19," "immunological effects in liver in COVID-19," and "SARS-CoV-2." This concise review will aid clinicians and researchers in better understanding the tissue histopathology and immunological consequences of SARS-CoV-2 on the liver, enabling improved care planning and avoiding future dangers.

Coronavirus disease 2019 and the liver

PURPOSE OF REVIEW

The objective of this review is to examine the epidemiology and pathogenesis of liver injury in coronavirus disease 2019 (COVID-19) and the impact of COVID-19 on patients with chronic liver disease (CLD) and liver transplant recipients.

RECENT FINDINGS

Abnormal liver chemistries occur in up to 60% of COVID-19 patients and are typically mild. COVID-19- associated liver injury may be because of direct viral cytopathic effect, immune-mediated damage, hypoxia, drug-induced liver injury (DILI), or exacerbation of CLD. COVID-19 patients with CLD and who are liver transplant recipients are at risk for severe disease and mortality. COVID-19 precipitated hepatic decompensation in 20-46% of cirrhotic patients. Alcohol consumption and cases of acute alcohol- associated hepatitis increased during the COVID-19 pandemic. Corticosteroids and calcineurin inhibitors are well tolerated to use during COVID-19 but immunomodulators have been associated with mortality. Less than 50% of transplant recipients produce adequate antibody titers after COVID-19 vaccination.

SUMMARY

COVID-19 patients with CLD should be monitored for liver injury and hepatic decompensation. Patients with CLD and liver transplant recipients should be considered for targeted COVID-19 pharmacotherapeutics and advised vaccination against COVID-19, including a third booster dose. CLD treatments and immunosuppression in liver transplant recipients could generally continue without interruption during COVID-19 infection, with the possible exception of immunomodulators.

Liver Dysfunction in COVID-19: From Onset to Recovery

With the spread of coronavirus disease 2019 (COVID-19) worldwide, extrapulmonary lesions, including liver dysfunction, have attracted growing attention. The mechanisms underlying liver dysfunction in COVID-19 remain unclear. The reported prevalence of liver dysfunction varies widely across studies. In addition, its impact on clinical outcomes and its recovery after discharge are still controversial. In this review, pathological and laboratory findings were analyzed to reveal the potential mechanisms of COVID-19-induced liver injury from onset to recovery. Four patterns of liver damage were summarized according to the pathological findings, including hypoxemia and shock changes, vascular thrombosis and vascular damage, bile duct damage, and other histological changes. With a strict definition, the prevalence of liver dysfunction was not as high as reported. Meanwhile, liver dysfunction improved during the process of recovery. Nevertheless, the definite liver dysfunction was significantly associated with severe clinical course, which should not be ignored.

Liver injury in COVID-19: pathological findings

Hepatic injuries have been reported in patients with Coronavirus disease 2019 infection, particularly in those with moderate to severe illness. To date, pathological changes caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in liver tissue are unclear. Moreover, the mechanisms involved in liver injury in Coronavirus disease 2019 infection are not yet established. In this paper, we summarize the spectrum of pathologic findings of liver injury in patients infected by SARS-CoV-2 and we discuss the clinicopathological correlation and the mechanisms of liver damage in Coronavirus disease 2019 infection.

Postmortem findings in COVID-19 fatalities: A systematic review of current evidence

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing pandemic of coronavirus disease 2019 (COVID-19). Almost 17 months after the first COVID-19 case was reported, the exact pathogenesis of the virus is still open to interpretation. Postmortem studies have been relatively scarce due to the high infectivity rate of the virus. We systematically reviewed the literature available for studies that reported gross, histological, microscopic, and immunohistochemical findings in COVID-19 fatalities with the aim of reporting any recurrent findings among different demographics. PubMed and Scopus were searched up till the second of May 2021 and 46 studies with a total of 793 patients were shortlisted after the application of inclusion and exclusion criteria. The selected studies reported gross, histological, microscopic, and immunohistochemical autopsy findings in the lungs, heart, liver, gallbladder, bowels, kidney, spleen, bone marrow, lymph nodes, CNS, pancreas, endocrine/exocrine glands, and a few other miscellaneous locations. The SARS-CoV-2 virus was detected in multiple organs and so was the presence of widespread microthrombi. This finding suggests that the pathogenesis of this highly infectious virus might be linked to some form of coagulopathy. Further studies should focus on analyzing postmortem findings in a larger number of patients from different demographics in order to obtain more generalizable results.

Covid-19 and Liver Injury: Role of Inflammatory Endotheliopathy, Platelet Dysfunction, and Thrombosis

Liver injury, characterized predominantly by elevated aspartate aminotransferase and alanine aminotransferase, is a common feature of coronavirus disease 2019 (COVID-19) symptoms caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Additionally, SARS-CoV-2 infection is associated with acute-on-chronic liver failure in patients with cirrhosis and has a notably elevated mortality in patients with alcohol-related liver disease compared to other etiologies. Direct viral infection of the liver with SARS-CoV-2 remains controversial, and alternative pathophysiologic explanations for its hepatic effects are an area of active investigation. In this review, we discuss the effects of SARS-CoV-2 and the inflammatory environment it creates on endothelial cells and platelets more generally and then with a hepatic focus. In doing this, we present vascular inflammation and thrombosis as a potential mechanism of liver injury and liver-related complications in COVID-19.

Increased Hepatic Expression of SARS-CoV-2 Entry Points and Proinflammatory Cytokines in Cirrhosis

It has been recently reported that patients with cirrhosis have significantly higher mortality following severe acute respiratory syndrome coronavrisu 2 (SARS-CoV-2) infection compared with those without.^1,2 Specifically, it was demonstrated that mortality was greater in those with advanced cirrhosis (Child-Pugh B and C), and that from cirrhotic patients experiencing SARS-CoV-2 infection, close to half suffer acute decompensation including acute-on-chronic liver failure (ACLF).² Unfortunately, the presence of hepatic decompensation at baseline has been shown to be an independent predictor of all-cause mortality in patients with coronavirus disease 2019 (COVID-19).¹ Patients with decompensated cirrhosis contracting COVID-19 have a poor outcome, with an overall reported mortality of over 30%.¹.

Case Report: SARS-CoV-2 as an unexpected causal agent of predominant febrile hepatitis

Background: Respiratory symptoms and pneumonia are the predominant features of Coronavirus disease 2019 (COVID-19) due to emerging SARS-CoV-2 virus, but extrapulmonary manifestations are also observed. For instance, some degree of liver injury has been described among patients requiring hospital admission for severe COVID-19. However, acute febrile hepatitis as an initial or predominant manifestation of COVID-19 has been rarely reported. Case presentation: A 34-year-old man without underlying medical conditions presented with fever of unknown origin for two weeks in the absence of respiratory symptoms or other complaints. Laboratory testing revealed isolated acute hepatitis, for which an extensive microbiological work-up did not reveal identification of the causal agent. PCR testing for SARS-CoV-2 on a nasopharyngeal swab was negative on two occasions and initial serology for SARS-CoV-2 (at 15 days from symptoms onset) was also negative. However, repeated SARS-CoV-2 serological testing at 30 days demonstrated seroconversion leading to the diagnosis of COVID-19-related hepatitis. The patient's condition progressively improved, while transaminases steadily declined and eventually returned back to normal within 30 days. Conclusions: We describe here a unique case of SARS-CoV-2 isolated febrile hepatitis in a young and previously healthy man, which was diagnosed by demonstration of seroconversion, while PCR screening was negative. This case report highlights the role of repeated serological testing for the diagnosis of extrapulmonary manifestations of COVID-19.

Coronavirus disease 2019 in liver transplant patients: Clinical and therapeutic aspects

The coronavirus disease 2019 (COVID-19) pandemic has profoundly impacted liver transplant (LT) activity across the world, with notable decreases in the number of donations and procedures in most Western countries, in particular throughout the first wave. The cumulative incidence of COVID-19 in LT recipients (with estimates ranging from 0.34% to 1.56%) appears to be at least comparable to that observed for the general population. Clinical and radiological features at presentation are also similar to non-transplant patients. The risk of death among LT recipients requiring hospital admission is high (from 12% to 19%), although some authors have suggested that overall mortality may be actually lower compared to the general non-transplant population. It is likely that these poor outcomes may be mainly influenced by the older age and higher comorbidity burden of LT recipients, rather than by the transplant status itself. In fact, it has been hypothesized that post-transplant immunosuppression would exert a protective role, with special focus on tacrolimus-containing regimens. There is scarce evidence to guide the optimal management of post-transplant COVID-19 and the use of antiviral or immunomodulatory therapies, although both clinical practice and guidelines support the dose reduction or withdrawal of anti-proliferative agents such as mofetil mycophenolate. Preliminary reports suggest that the antibody response to messenger RNA vaccines is significantly impaired as compared to non-immunocompromised individuals, in line with other transplant populations. Finally, it is foreseeable that the future will be conditioned by the emerging variants of severe acute respiratory syndrome coronavirus 2 with increased transmissibility among LT recipients.

Intriguing findings of liver fibrosis following COVID-19

Background

Studies on a new coronavirus disease (COVID-19) show the elevation of liver enzymes and liver fibrosis index (FIB-4) independently on pre-existing liver diseases. It points to increased liver fibrogenesis during acute COVID-19 with possible long-term consequences. This study aimed to assess liver fibrosis in COVID-19 patients by serum hyaluronic acid (HA) and FIB-4.

Methods

The study included the acute COVID-19 group (66 patients, 50% females, mean age 58.3 ± 14.6), the post-COVID group (58 patients in 3–6 months after the recovery, 47% females, mean age 41.2 ± 13.4), and a control group (17 people, 47% females, mean age 42.8 ± 11.0). Ultrasound elastography was performed in the post-COVID and control groups.

Results

Sixty-five percent of the acute COVID-19 group had increased FIB-4 (> 1.45), and 38% of patients had FIB-4 ≥ 3.25. After matching by demographics, 52% of acute COVID-19 and 5% of the post-COVID group had FIB-4 > 1.45, and 29% and 2% of patients had FIB-4 ≥ 3.25, respectively. Increased serum HA (≥ 75 ng/ml) was observed in 54% of the acute COVID-19 and 15% of the post-COVID group. In the acute COVID-19 group, HA positively correlated with FIB-4, AST, ALT, LDH, IL-6, and ferritin and negatively with blood oxygen saturation. In the post-COVID group, HA did not correlate with FIB-4, but it was positively associated with higher liver stiffness and ALT.

Conclusion

More than half of acute COVID-19 patients had increased serum HA and FIB-4 related to liver function tests, inflammatory markers, and blood oxygen saturation. It provides evidence for the induction of liver fibrosis by multiple factors during acute COVID-19. Findings also indicate possible liver fibrosis in about 5% of the post-COVID group.

Pathological characteristics of liver sinusoidal thrombosis in COVID-19 patients: A series of 43 cases

AIM

Coronavirus disease (COVID-19) is characterized by pneumonia with secondary damage to multiple organs including the liver. Liver injury (elevated alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) often correlates with disease severity in COVID-19 patients. The aim of this study is to identify pathological microthrombi in COVID-19 patient livers by correlating their morphology with liver injury, and examine hyperfibrinogenemia and von Willebrand factor (vWF) as mechanisms of their formation.

METHODS

Forty-three post-mortem liver biopsy samples from COVID-19 patients were obtained from Papa Giovanni XXIII Hospital in Bergamo, Italy. Three morphological features of microthrombosis (sinusoidal erythrocyte aggregation [SEA], platelet microthrombi [PMT], and fibrous thrombi) were evaluated.

RESULTS

We found liver sinusoidal microthrombosis in 23 COVID-19 patients (53%) was associated with a higher serum ALT and AST level compared to those without (ALT: 10-fold, p = 0.04; AST: 11-fold, p = 0.08). Of 43 livers, PMT and SEA were observed in 14 (33%) and 19 (44%) cases, respectively. Fibrous thrombi were not observed. Platelet microthrombi were associated with increased ALT (p < 0.01), whereas SEA was not (p = 0.73). In COVID-19 livers, strong vWF staining in liver sinusoidal endothelial cells was associated with significantly increased platelet adhesion (1.7-fold, p = 0.0016), compared to those with weak sinusoidal vWF (2-fold, p < 0.0001). Sinusoidal erythrocyte aggregation in 19 (83%) liver samples was mainly seen in zone 2. Livers with SEA had significantly higher fibrinogen (1.6-fold, p = 0.031) compared to those without SEA in COVID-19 patients.

CONCLUSIONS

Liver PMT is a pathologically important thrombosis associated with liver injury in COVID-19, while SEA is a unique morphological feature of COVID-19 patient livers. Sinusoidal vWF and hyperfibrinogenemia could contribute to PMT and SEA formation.

Correlation Between Clinical and Pathological Findings of Liver Injury in 27 Patients With Lethal COVID-19 Infections in Brazil

Liver test abnormalities are frequently observed in patients with coronavirus disease 2019 (COVID‐19) and are associated with worse prognosis. However, information is limited about pathological changes in the liver in this infection, so the mechanism of liver injury is unclear. Here we describe liver histopathology and clinical correlates of 27 patients who died of COVID‐19 in Manaus, Brazil. There was a high prevalence of liver injury (elevated alanine aminotransferase and aspartate aminotransferase in 44% and 48% of patients, respectively) in these patients. Histological analysis showed sinusoidal congestion and ischemic necrosis in more than 85% of the cases, but these appeared to be secondary to systemic rather than intrahepatic thrombotic events, as only 14% and 22% of samples were positive for CD61 (marker of platelet activation) and C4d (activated complement factor), respectively. Furthermore, the extent of these vascular findings did not correlate with the extent of transaminase elevations. Steatosis was present in 63% of patients, and portal inflammation was present in 52%. In most cases, hepatocytes expressed angiotensin‐converting enzyme 2 (ACE2), which is responsible for binding and entry of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), even though this ectoenzyme was minimally expressed on hepatocytes in normal controls. However, SARS‐CoV‐2 staining was not observed. Most hepatocytes also expressed inositol 1,4,5‐triphosphate receptor 3 (ITPR3), a calcium channel that becomes expressed in acute liver injury. Conclusion: The hepatocellular injury that commonly occurs in patients with severe COVID‐19 is not due to the vascular events that contribute to pulmonary or cardiac damage. However, new expression of ACE2 and ITPR3 with concomitant inflammation and steatosis suggests that liver injury may result from inflammation, metabolic abnormalities, and perhaps direct viral injury.

SARS-CoV-2-associated gastrointestinal and liver diseases: what is known and what is needed to explore

BACKGROUND

The pandemic of COVID19 which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first described in China as an unexplained pneumonia transmitted by respiratory droplets. Gastrointestinal (GI) and liver injury associated with SARS-CoV-2 infection were reported as an early or sole disease manifestation, mainly outside China. The exact mechanism and incidence of GI and liver involvement are not well elucidated.

MAIN BODY

We conducted a PubMed search for all articles written in the English language about SARS-CoV-2 affecting the GI and liver. Following data extraction, 590 articles were selected. In addition to respiratory droplets, SARS-CoV-2 may reach the GI system through the fecal-oral route, saliva, and swallowing of nasopharyngeal fluids, while breastmilk and blood transmission were not implicated. Moreover, GI infection may act as a septic focus for viral persistence and transmission to the liver, appendix, and brain. In addition to the direct viral cytopathic effect, the mechanism of injury is multifactorial and is related to genetic and demographic variations. The most frequently reported GI symptoms are diarrhea, nausea, vomiting, abdominal pain, and bleeding. However, liver infection is generally discovered during laboratory testing or a post-mortem. Radiological imaging is the gold standard in diagnosing COVID-19 patients and contributes to understanding the mechanism of extra-thoracic involvement. Medications should be prescribed with caution, especially in chronic GI and liver patients.

CONCLUSION

GI manifestations are common in COVID-19 patients. Special care should be paid for high-risk patients, older males, and those with background liver disease.

L-SIGN is a receptor on liver sinusoidal endothelial cells for SARS-CoV-2 virus

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a pandemic. Severe disease is associated with dysfunction of multiple organs, but some infected cells do not express ACE2, the canonical entry receptor for SARS-CoV-2. Here, we report that the C-type lectin receptor L-SIGN interacted in a Ca²⁺-dependent manner with high-mannose–type N-glycans on the SARS-CoV-2 spike protein. We found that L-SIGN was highly expressed on human liver sinusoidal endothelial cells (LSECs) and lymph node lymphatic endothelial cells but not on blood endothelial cells. Using high-resolution confocal microscopy imaging, we detected SARS-CoV-2 viral proteins within the LSECs from liver autopsy samples from patients with COVID-19. We found that both pseudo-typed virus enveloped with SARS-CoV-2 spike protein and authentic SARS-CoV-2 virus infected L-SIGN–expressing cells relative to control cells. Moreover, blocking L-SIGN function reduced CoV-2–type infection. These results indicate that L-SIGN is a receptor for SARS-CoV-2 infection. LSECs are major sources of the clotting factors vWF and factor VIII (FVIII). LSECs from liver autopsy samples from patients with COVID-19 expressed substantially higher levels of vWF and FVIII than LSECs from uninfected liver samples. Our data demonstrate that L-SIGN is an endothelial cell receptor for SARS-CoV-2 that may contribute to COVID-19–associated coagulopathy.

Inflammatory effect on the gastrointestinal system associated with COVID-19

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) that causes coronavirus disease-2019 (COVID-19) has provoked a global pandemic, mainly affecting the respiratory tract; however, a percentage of infected individuals can develop gastrointestinal (GI) symptoms. Some studies describe the development of GI symptoms and how they affect the progression of COVID-19. In this review, we summarize the main mechanisms associated with gut damage during infection by SARS-CoV-2 as well as other organs such as the liver and pancreas. Not only are host factors associated with severe COVID-19 but intestinal microbiota dysbiosis is also observed in patients with severe disease.

Liver injury in COVID-19: Detection, pathogenesis, and treatment

In the early December 2019, a novel coronavirus named severe acute respiratory syndrome coronavirus 2 was first reported in Wuhan, China, followed by an outbreak that spread around the world. Numerous studies have shown that liver injury is common in patients with coronavirus disease 2019 (COVID-19), and may aggravate the severity of the disease. However, the exact cause and specific mechanism of COVID-associated liver injury needs to be elucidated further. In this review, we present an analysis of the clinical features, potential mechanisms, and treatment strategies for liver injury associated with COVID-19. We hope that this review would benefit clinicians in devising better strategies for management of such patients.

Laboratory hematologic features of COVID-19 associated liver injury: A systematic review

BACKGROUND

Liver injury is a common complication of infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The utility of laboratory hematology data in the diagnosis and risk stratification of patients with coronavirus disease 2019 (COVID-19) has not been comprehensively examined.

AIM

To address the following. (1) Are the abnormalities in hematologic parameters seen in the general population of patients with COVID-19 also seen in those patients with associated liver injury? (2) Is liver injury in COVID-19 a sign of severe disease and does liver injury correlate with hematologic markers of severe disease? And (3) What is the quality of this evidence?

METHODS

To address these questions, a comprehensive systematic review was performed. We searched the peer reviewed medical literature using MEDLINE (PubMed interface), Web of Science, and EMBASE for cohort studies that specifically addressed liver injury and COVID-19 without limitation of date of publication or language. A quality assessment of the studies was performed using the Newcastle-Ottawa Scale.

RESULTS

Thirty-two articles were suitable for inclusion in our systematic review. These included 22 articles with a cohort of COVID-19 patients with liver injury, 5 comparing non-severe vs severe COVID-19 populations in which liver injury was addressed, and 5 other cohort studies with a focus on liver injury. White blood cell count, absolute neutrophil count, absolute lymphocyte count (ALC), and hemoglobin were the parameters most helpful in distinguishing COVID-19 with liver injury from COVID-19 without liver injury. ALC and d-dimer were identified as being potentially useful in distinguishing non-severe from severe COVID-19. Liver injury was more frequently seen in cohorts with severe disease. Most studies were of high quality (24/48, 86%) with 4/28 (14%) of moderate quality and 0 of low quality.

CONCLUSION

Our study supports the use of select hematologic parameters in diagnosis and risk stratification of liver injury in COVID-19 patients. Although of overall high quality, the current medical literature is limited by the small number of studies with high statistical power and the variable definition of COVID-19 liver injury in the literature.

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.