Systemic viral infections and collateral damage in the liver

New insights into therapeutic strategies for targeting hepatic macrophages to alleviate liver fibrosis

Liver fibrosis is a wound-healing response induced by persistent liver damage, resulting from complex multicellular interactions and multifactorial networks. Without intervention, it can progress to cirrhosis and even liver cancer. Current understanding suggests that liver fibrosis is reversible, making it crucial to explore effective therapeutic strategies for its alleviation. Chronic inflammation serves as the primary driver of liver fibrosis, with hepatic macrophages playing a dual role depending on their polarization state. This review summarizes various prevention and therapeutic strategies targeting hepatic macrophages in the context of liver fibrosis. These strategies include inhibition of macrophage recruitment, modulation of macrophage activation and polarization, regulation of macrophage metabolism, and induction of phagocytosis and autophagy in hepatic macrophages. Additionally, we discuss the communication between hepatic macrophages, hepatocytes, and hepatic stellate cells (HSCs), as well as the current clinical application of anti-fibrotic drugs targeting macrophages. The goal is to identify effective therapeutic targets at each stage of macrophage participation in liver fibrosis development, with the aim of using hepatic macrophages as a target for liver fibrosis treatment.

Hepatic phenomena associated with SARS-CoV-2: Acute liver injury, autoimmune hepatitis and post-vaccination

The infection with SARS-CoV-2, primarily recognized for its respiratory effects, reveals itself as a multifaceted clinical phenomenon, extending beyond the pulmonary realm. Accompanied by gastrointestinal, neurological, thromboembolic, cardiovascular, and immune-related manifestations, the complexity of the systemic repercussions of the disease becomes apparent. Genetic predisposition is a significant factor in the development of autoimmune hepatitis, as both viruses, such as SARS-CoV-2, and drugs, including vaccines, can act as triggers in genetically susceptible individuals. A profound understanding of these mechanisms is essential to effectively address the clinical complexity of SARS-CoV-2 infection.

Viral sepsis: diagnosis, clinical features, pathogenesis, and clinical considerations

Sepsis, characterized as life-threatening organ dysfunction resulting from dysregulated host responses to infection, remains a significant challenge in clinical practice. Despite advancements in understanding host-bacterial interactions, molecular responses, and therapeutic approaches, the mortality rate associated with sepsis has consistently ranged between 10 and 16%. This elevated mortality highlights critical gaps in our comprehension of sepsis etiology. Traditionally linked to bacterial and fungal pathogens, recent outbreaks of acute viral infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), influenza virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), among other regional epidemics, have underscored the role of viral pathogenesis in sepsis, particularly when critically ill patients exhibit classic symptoms indicative of sepsis. However, many cases of viral-induced sepsis are frequently underdiagnosed because standard evaluations typically exclude viral panels. Moreover, these viruses not only activate conventional pattern recognition receptors (PRRs) and retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) but also initiate primary antiviral pathways such as cyclic guanosine monophosphate adenosine monophosphate (GMP-AMP) synthase (cGAS)-stimulator of interferon genes (STING) signaling and interferon response mechanisms. Such activations lead to cellular stress, metabolic disturbances, and extensive cell damage that exacerbate tissue injury while leading to a spectrum of clinical manifestations. This complexity poses substantial challenges for the clinical management of affected cases. In this review, we elucidate the definition and diagnosis criteria for viral sepsis while synthesizing current knowledge regarding its etiology, epidemiology, and pathophysiology, molecular mechanisms involved therein as well as their impact on immune-mediated organ damage. Additionally, we discuss clinical considerations related to both existing therapies and advanced treatment interventions, aiming to enhance the comprehensive understanding surrounding viral sepsis.

Causal relationship between blood traits and severe influenza A(H1N1)pdm09 infection in East Asian: A Mendelian randomization study

Although a range of blood traits have been reported to be associated with influenza A(H1N1)pdm09 (H1N1pdm09) disease severity, their underlying causal relationships and biological mechanisms have remained unclear. This study aimed to investigate the causal relationship between blood traits and H1N1pdm09 using a two-sample Mendelian randomization analysis. Based on the data from our in-house genome-wide association study (GWAS) on H1N1pdm09 disease severity (Ncase [severe] = 70, Ncontrol [mild] = 95) and GWAS summaries of 44 blood traits from Biobank Japan (N = 12 303-143 658), we identified the potential causal effect of blood traits on severe H1N1pdm09. The inverse variance weighted method analysis revealed significant causal effects of lower aspartate aminotransferase (AST, β = -3.212, p = 0.019), low-density-lipoprotein cholesterol (LDL-C, β = -1.372, p = 0.045), and basophil counts (Baso, β = -1.638, p = 0.047) on severe H1N1pdm09 disease. Additionally, polygenic risk score analysis further confirmed genetic overlap between these blood traits and severe H1N1pdm09 disease. This study provided evidence linking the lower level of AST, LDL-C, and lower count of Baso with severe H1N1pdm09 disease, potentially identifying new therapeutic targets for patients with severe influenza.

Integrated multi-omics analysis reveals liver metabolic reprogramming by fish iridovirus and antiviral function of alpha-linolenic acid

Iridovirus poses a substantial threat to global aquaculture due to its high mortality rate; however, the molecular mechanisms underpinning its pathogenesis are not well elucidated. Here, a multi-omics approach was applied to groupers infected with Singapore grouper iridovirus (SGIV), focusing on the roles of key metabolites. Results showed that SGIV induced obvious histopathological damage and changes in metabolic enzymes within the liver. Furthermore, SGIV significantly reduced the contents of lipid droplets, triglycerides, cholesterol, and lipoproteins. Metabolomic analysis indicated that the altered metabolites were enriched in 19 pathways, with a notable down-regulation of lipid metabolites such as glycerophosphates and alpha-linolenic acid (ALA), consistent with disturbed lipid homeostasis in the liver. Integration of transcriptomic and metabolomic data revealed that the top enriched pathways were related to cell growth and death and nucleotide, carbohydrate, amino acid, and lipid metabolism, supporting the conclusion that SGIV infection induced liver metabolic reprogramming. Further integrative transcriptomic and proteomic analysis indicated that SGIV infection activated crucial molecular events in a phagosome-immune depression-metabolism dysregulation-necrosis signaling cascade. Of note, integrative multi-omics analysis demonstrated the consumption of ALA and linoleic acid (LA) metabolites, and the accumulation of L-glutamic acid (GA), accompanied by alterations in immune, inflammation, and cell death-related genes. Further experimental data showed that ALA, but not GA, suppressed SGIV replication by activating antioxidant and anti-inflammatory responses in the host. Collectively, these findings provide a comprehensive resource for understanding host response dynamics during fish iridovirus infection and highlight the antiviral potential of ALA in the prevention and treatment of iridoviral diseases.

Coronavirus disease 19 (Covid-19): A comparative study of pattern of liver injury in adult patients in different waves of Covid-19 infection

BACKGROUND AND STUDY AIMS

Liver dysfunction is a common manifestation of the COVID-19 infection. We aimed to study transaminase abnormalities through different waves of COVID-19 and their relations to disease severity or mortality.

PATIENTS AND METHODS

A retrospective study included 521 Egyptian patients diagnosed with COVID-19. Data was retrieved from the medical records of patients who were admitted from April 2020 to October 2021 in Kasr Al-Ainy Hospitals, Cairo University, with categorization according to disease severity in correspondence to the four waves.

RESULTS

The median age was lower in the first wave compared to other waves, with male predominance across all waves. The most commonly encountered comorbidity overall was hypertension, followed by diabetes mellitus. White blood cells, ferritin, and interleukin-6 showed the highest median values in the second wave, with significantly higher median C-reactive protein on day 1 in the first wave. Forty percent of the patients showed elevated hepatic transaminases on admission in four waves, with no statistically significant difference between waves. On day 5, around half of the patients had elevated transaminases, with no significant difference between waves. Most CT findings were of moderate severity. Clinical severity was higher in the second wave. It was observed that the higher the disease severity, the greater the proportion of patients with elevated hepatic transaminases. The mortality rate was markedly high in cases who had elevated ALT or AST on day 5. The association between elevated enzymes on admission and mortality was seen in the first wave only, with a fatality rate of 22.5% in cases with increased baseline ALT and AST versus 5% in those with normal baseline enzymes.

CONCLUSION

There was no significant difference in transaminases between the four waves. Elevated transaminases were positively associated with increased mortality and severity, reflecting their prognostic value.

Liver abnormalities following SARS-CoV-2 infection in children 1 to 10 years of age

OBJECTIVE

Beginning in October 2021 in the USA and elsewhere, cases of severe paediatric hepatitis of unknown aetiology were identified in young children. While the adenovirus and adenovirus-associated virus have emerged as leading aetiological suspects, we attempted to investigate a potential role for SARS-CoV-2 in the development of subsequent liver abnormalities.

DESIGN

We conducted a study using retrospective cohorts of deidentified, aggregated data from the electronic health records of over 100 million patients contributed by US healthcare organisations.

RESULTS

Compared with propensity score matched children with other respiratory infections, children aged 1-10 years with COVID-19 had a higher risk of elevated transaminases (HR (95% CI) 2.16 (1.74 to 2.69)) or total bilirubin (HR (95% CI) 3.02 (1.91 to 4.78)), or new diagnoses of liver diseases (HR (95% CI) 1.67 (1.21 to 2.30)) from 1 to 6 months after infection. Patients with pre-existing liver abnormalities, liver abnormalities surrounding acute infection, younger age (1-4 years) or illness requiring hospitalisation all had similarly elevated risk. Children who developed liver abnormalities following COVID-19 had more pre-existing conditions than those who developed abnormalities following other infections.

CONCLUSION

These results indicate that SARS-CoV-2 may prime the patient for subsequent development of liver infections or non-infectious liver diseases. While rare (~1 in 1000), SARS-CoV-2 is a risk for subsequent abnormalities in liver function or the diagnosis of diseases of the liver.

Involvement of TLR4 in Acute Hepatitis Associated with Airway Infection of Murine γ-Herpesvirus 68

Extrahepatic viral infections are often accompanied by acute hepatitis, as evidenced by elevated serum liver enzymes and intrasinusoidal infiltration of CD8+ T cells, without direct infection of the liver. An example is infectious mononucleosis caused by primary infection with EBV. Previously, we demonstrated that airway infection of mice with murine γ-herpesvirus 68 (MHV68), a murine model of EBV, caused liver inflammation with elevated serum liver enzymes and intrahepatic infiltration of IFN-γ-producing CD8+ T cells and NK cells. Mechanistically, the expression of the CXCR3-ligand chemokines, which are commonly induced by IFN-γ and attract IFN-γ-producing Th1-type cells via CXCR3, was upregulated in the liver. Importantly, the liver inflammation was suppressed by oral neomycin, an intestine-impermeable aminoglycoside, suggesting an involvement of some products from the intestinal microbiota. In this study, we showed that the liver inflammation and the expression of the CXCR3-ligand chemokines in the liver were effectively ameliorated by i.p. administration of anti-TLR4 mAb or C34, a TLR4 blocker, as well as in TLR4-deficient mice. Conversely, intrarectal inoculation of Escherichia coli as an extraintestinal source of LPS aggravated liver inflammation in MHV68-infected mice with increased expression of the CXCR3-ligand chemokines in the liver. In contrast, the lung inflammation in MHV68-infected mice was not affected by oral neomycin, i.p. administration of C34, or TLR4 deficiency. Collectively, the LPS-TLR4 pathway plays a pivotal role in the liver inflammation of MHV68-infected mice at least in part by upregulating the CXCR3-ligand chemokines in the liver.

Liver abnormalities following SARS-CoV-2 infection in children under 10 years of age

Objective

Beginning in October 2021 in the US and elsewhere, cases of severe pediatric hepatitis of unknown etiology were identified in young children. While the adenovirus and adenovirus-associated virus have emerged as leading etiologic suspects, we attempted to investigate a potential role for SARS-CoV-2 in the development of subsequent liver abnormalities.

Design

We conducted a study utilizing retrospective cohorts of de-identified, aggregated data from the electronic health records of over 100 million patients contributed by US health care organizations.

Results

Compared to propensity-score-matched children with other respiratory infections, children aged 1-10 years with COVID-19 had a higher risk of elevated transaminases (Hazard ratio (HR) (95% Confidence interval (CI)) 2.16 (1.74-2.69)) or total bilirubin (HR (CI) 3.02 (1.91-4.78)), or new diagnoses of liver diseases (HR (CI) 1.67 (1.21-2.30)) from one to six months after infection. Patients with pre-existing liver abnormalities, liver abnormalities surrounding acute infection, younger age (1-4 years), or illness requiring hospitalization all had similarly elevated risk. Children who developed liver abnormalities following COVID-19 had more pre-existing conditions than those who developed abnormalities following other infections.

Conclusion

These results indicate that SARS-CoV-2 may prime the patient for subsequent development of liver infections or non-infectious liver diseases. While rare (~1 in 1,000), SARS-CoV-2 is a risk for subsequent abnormalities in liver function or the diagnosis of diseases of the liver.

What is already known on this topic

Clusters of severe hepatitis in children in 2022 coincident with the increase in COVID-19 infections in children raised the question of the contribution of SARS-CoV-2 to the hepatitis outbreak, though it was soon determined that SARS-CoV-2 was not the primary etiologic agent.

What this study adds

SARS-CoV-2 may prime the patient for subsequent development of liver infections or non-infectious liver diseases.

How this study might affect research practice or policy

Despite the mild initial disease in children, there may be longer term consequences of COVID-19, such as liver abnormalities, that warrants further investigation.

COVID-19 associated liver injury: An updated review on the mechanisms and management of risk groups

Coronavirus disease 2019 (COVID-19) has been associated with various liver injury cases worldwide. To date, the prevalence, mechanism, clinical manifestations, diagnosis, and outcomes of COVID-19-induced liver injury in various at-risk groups are not well defined. Liver injury may arise in the prevention and treatment of COVID-19 from direct causes such as viral infection and indirect causes such as systemic inflammation, hypoxic changes, and drugs that exacerbate any pre-existing liver disease. Studies have found that patients with underlying liver disease are at higher risk of COVID-19-induced liver injury. Certain condition of cardiopulmonary and metabolic diseases and vulnerable stages in lifespan may also involve in the development of COVID-19-induced liver injury. This review summarized studies of COVID-19-induced liver injury in different at-risk groups regarding their clinical characteristics, parameters, and correlations of the severity with these indicators and signs as well as potential treatment suggestions, to increase attention to physiological and pathological conditions and continue liver function monitoring as they can help in strengthening early supportive treatment and reducing the incidence of adverse outcomes.

Liver injury in patients with COVID-19 in comparison to patients with the pandemic influenza A (H1N1) 2009: a population-based study

BACKGROUND

Elevated liver tests in patients with COVID-19 are widely reported. Population-based studies utilizing a validated analysis of drug-induced liver injury (DILI), with a control group of other viral illnesses and follow-up are largely lacking.

MATERIALS AND METHODS

All hospitalized patients in Iceland with SARS-CoV-2 in 2020 and pandemic influenza A (H1N1) in 2009 were included in this retrospective, population-based study. Liver tests were compared between the two groups and the correlation to inflammatory markers and persistence of alanine aminotransferase (ALT) elevations were assessed. Potential DILI cases were reviewed using the Roussel Uclaf Causality Assessment Method (RUCAM).

RESULTS

225 SARS-CoV-2-positive and 73 influenza A (H1N1)-positive patients were included. Liver test values were similar between the groups, except for aspartate aminotransferase (AST) which was significantly lower in COVID-19, with a mean difference of 26 U/L (95%CI 4.2-47). Ferritin elevation was positively correlated with ALT, AST and alkaline phosphatase. No patient had persistently elevated ALT in COVID-19 and none had a probable DILI. Only 3 patients had a possible DILI according to the RUCAM.

CONCLUSIONS

Elevated liver enzymes are not specific for COVID-19. Hyperferritinemia was associated with elevated liver tests. DILI was very rare in COVID-19 and an unlikely cause of elevated liver enzymes in COVID-19. Abnormal liver tests are nonpersistent and generally not clinically important in these patients.

Post-COVID-19 cholangiopathy: A systematic review

BACKGROUND

The recent and still ongoing pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entailed various long-term complications, including post-infectious cholangiopathy.

AIM

To identify the available studies concerning post-coronavirus disease 2019 (COVID-19) cholangiopathy.

METHODS

An extensive bibliographical search was carried out in PubMed and in Cochrane Library to identify the articles (retrospective and prospective studies, cohort studies, case series and case reports) published between January 1, 2020 and August 22, 2022, using both MeSH terms and free-language keywords: cholangiopathy; COVID-19; post-COVID-19 cholangiopathy; SARS-CoV-2.

RESULTS

Thirteen studies fulfilled the inclusion criteria, which included 64 patients suffering from this condition. The patients were male in 82.8% of cases. Liver transplant was executed in 6 patients and scheduled in 7 patients, while 2 patients refused the surgical approach. Therefore in 23.4% of the cases, performing this procedure appeared to be necessary.

CONCLUSION

This review has revealed that generally the involvement of the liver in the course of SARS-CoV-2 infection is mild and transient, inducing cholestasis of cholangiocytes but can also be severe enough to cause organ failure in some cases.

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.

Impact of chronic liver disease on SARS-CoV-2 infection outcomes: Roles of stage, etiology and vaccination

Since the first identification in December of 2019 and the fast spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, it has represented a dramatic global public health concern. Though affecting mainly the respiratory system, SARS-CoV-2 disease, defined as coronavirus disease 2019 (COVID-19), may have a systemic involvement leading to multiple organ dysfunction. Experimental evidence about the SARS-CoV-2 tropism for the liver and the increasing of hepatic cytolysis enzymes during infection support the presence of a pathophysiological relationship between liver and SARS-CoV-2. On the other side, patients with chronic liver disease have been demonstrated to have a poor prognosis with COVID-19. In particular, patients with liver cirrhosis appear extremely vulnerable to infection. Moreover, the etiology of liver disease and the vaccination status could affect the COVID-19 outcomes. This review analyzes the impact of the disease stage and the related causes on morbidity and mortality, clinical outcomes during SARS-CoV-2 infection, as well as the efficacy of vaccination in patients with chronic liver disease.

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.

Additional risk factors improve mortality prediction for patients hospitalized with influenza pneumonia: a retrospective, single-center case-control study

BACKGROUND

Severe influenza, especially influenza pneumonia, causes large numbers of deaths each year. Some patients who develop severe influenza have no known risk factors. In this study we investigated risk factors for mortality of patients with influenza A-related pneumonia who have different basic conditions. We also evaluated the power of pneumonia severity assessment tools in Chinese patients hospitalized with influenza A-related pneumonia. Together, these results could provide a basis for a screening method that has improved ability for the early identification of critical patients who will have poor prognoses in clinical practice.

METHODS

This single-center, retrospective case-control study included 152 adult patients with severe influenza over six influenza seasons. Data for diagnoses and demographics, as well clinical data, laboratory findings, treatment methods, 30-day and 60-day outcomes of the patients were collected. Patients who had any of the risk factors for severe influenza were included in the high-risk group, and those that had no known risk factors were included in the low-risk group.

RESULTS

The PSI, CURB-65 and PIRO-CAP tools all underestimated the mortality rate of patients hospitalized with influenza A-related pneumonia, and this underestimate was more pronounced for low-risk patients. D-dimer (Odds ratio [OR] = 1.052, 95% confidence interval [CI] 1.001-1.106, p = 0.045) and direct bilirubin (OR = 1.143, 95%CI 1.049-1.246, p = 0.002) were independent risk factors for mortality of patients with influenza A-related pneumonia. When used in combination with ferritin and D-dimer, the area under receiver operator characteristic curve (AUC_ROC) was 0.851 (95%CI 0.780-0.922, p < 0.001), 0.840 (95%CI 0.763-0.916, p < 0.001) and 0.829 (95%CI 0.748-0.911, p < 0.001) for PSI, CURB-65 and PIRO-CAP, respectively, which was higher than that obtained using PSI, CURB-65 and PIRO-CAP alone.

CONCLUSIONS

The findings demonstrate that currently used community-acquired pneumonia (CAP) scoring systems could underestimate the risk of influenza A-related pneumonia mortality. D-dimer was shown to be an independent risk factor of mortality for influenza A-related pneumonia in hospitalized patients, and a combination of D-dimer with ferritin could improve the predictive value of PSI, CURB-65 and PIRO-CAP for adverse prognoses of patients with influenza A-related pneumonia.

Post-COVID-19 cholangiopathy: A systematic review

BACKGROUND

The recent and still ongoing pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entailed various long-term complications, including post-infectious cholangiopathy.

AIM

To identify the available studies concerning post-coronavirus disease 2019 (COVID-19) cholangiopathy.

METHODS

An extensive bibliographical search was carried out in PubMed and in Cochrane Library to identify the articles (retrospective and prospective studies, cohort studies, case series and case reports) published between January 1, 2020 and August 22, 2022, using both MeSH terms and free-language keywords: cholangiopathy; COVID-19; post-COVID-19 cholangiopathy; SARS-CoV-2.

RESULTS

Thirteen studies fulfilled the inclusion criteria, which included 64 patients suffering from this condition. The patients were male in 82.8% of cases. Liver transplant was executed in 6 patients and scheduled in 7 patients, while 2 patients refused the surgical approach. Therefore in 23.4% of the cases, performing this procedure appeared to be necessary.

CONCLUSION

This review has revealed that generally the involvement of the liver in the course of SARS-CoV-2 infection is mild and transient, inducing cholestasis of cholangiocytes but can also be severe enough to cause organ failure in some cases.

Correlation between COVID-19 and hepatitis B: A systematic review

BACKGROUND

There is growing evidence that patients with coronavirus disease 2019 (COVID-19) frequently present with liver impairment. Hepatitis B virus (HBV) remains a major public health threat in current society. Both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HBV can cause liver damage, and current findings on whether HBV infection increases disease severity in COVID-19 patients are inconsistent, and whether SARS-CoV-2 infection accelerates hepatitis B progression or leads to a worse prognosis in hepatitis B patients has not been adequately elucidated.

AIM

To explore the complex relationship between COVID-19 and hepatitis B in order to inform the research and management of patients co-infected with SARS-CoV-2 and HBV.

METHODS

An experienced information specialist searched the literature in the following online databases: PubMed, China National Knowledge Infrastructure, Google Scholar, Scopus, Wiley, Web of Science, Cochrane, and ScienceDirect. The literature published from December 2019 to September 1, 2022 was included in the search. We also searched medRxiv and bioRxiv for gray literature and manually scanned references of included articles. Articles reporting studies conducted in humans discussing hepatitis B and COVID-19 were included. We excluded duplicate publications. News reports, reports, and other gray literature were included if they contained quantifiable evidence (case reports, findings, and qualitative analysis). Some topics that included HBV or COVID-19 samples but did not have quantitative evidence were excluded from the review.

RESULTS

A total of 57 studies were eligible and included in this review. They were from 11 countries, of which 33 (57.9%) were from China. Forty-two of the 57 studies reported abnormalities in liver enzymes, three mainly reported abnormalities in blood parameters, four indicated no significant liver function alterations, and another eight studies did not provide data on changes in liver function. Fifty-seven studies were retrospective and the total number of co-infections was 1932, the largest sample size was 7723, and the largest number of co-infections was 353. Most of the studies suggested an interaction between hepatitis B and COVID-19, while 12 studies clearly indicated no interaction between hepatitis B and COVID-19. Six of the 57 studies clearly reported HBV activation. Six studies were related to liver transplant patients.

CONCLUSION

There is some association between COVID-19 and hepatitis B. Future high-quality randomized trials are needed to further elucidate the interaction between COVID-19 and hepatitis B.

Nutraceutical prospects of Houttuynia cordata against the infectious viruses

The novel enveloped β-coronavirus SARS-CoV-2 (COVID-19) has offered a surprising health challenge all over the world. It develops severe pneumonia leading to acute respiratory distress syndrome (ARDS). Like SARS-COV-2, other encapsulated viruses like HIV, HSV, and influenza have also offered a similar challenge in the past. In this regard, many antiviral drugs are being explored with varying degrees of success to combat the associated pathological conditions. Therefore, upon scientific validation & development, these antiviral phytochemicals can attain a futuristic nutraceutical prospect in managing different encapsulated viruses. Houttuynia cordata (HC) is widely reported for activities such as antioxidant, anti-inflammatory, and antiviral properties. The major antiviral bioactive components of HC include essential oils (methyl n-nonyl ketone, lauryl aldehyde, capryl aldehyde), flavonoids (quercetin, rutin, hyperin, quercitrin, isoquercitrin), and alkaloids (norcepharadione B) & polysaccharides. HC can further be explored as a potential nutraceutical agent in the therapy of encapsulated viruses like HIV, HSV, and influenza. The review listed various conventional and green technologies that are being employed to extract potent phytochemicals with diverse activities from the HC. It was indicated that HC also inhibited molecular targets like 3C-like protease (3CLPRO) and RNA-dependent RNA polymerase (RdRp) of COVID-19 by blocking viral RNA synthesis and replication. Antioxidant and hepatoprotective effects of HC have been evident in impeding complications from marketed drugs during antiviral therapies. The use of HC as a nutraceutical is localized within some parts of Southeast Asia. Further technological advances can establish it as a nutraceutical-based functional food against pathogenic enveloped viruses like COVID 19.

Post-Covid- 19 Cholangiopathy:A Systematic Review

OBJECTIVES

Post COVID-19 cholangiopathy is a rare but poorly understood and serious complication of COVID-19 infection. We sought to better understand the epidemiology, mechanism of action, histology, imaging findings and outcomes of post-COVID-19 cholangiopathy.

METHODS

We searched PubMed, Cochrane Library, Embase, and Web of Science from December 2019 to December 2021. Mesh words used "post-Covid-19 cholangiopathy", "COVID-19 liver injury"," Covid-19 and cholangiopathy", and COVID-19 liver disease". The data on epidemiology, mechanism of action, histology, imaging findings and outcomes were collected.

RESULTS

Post COVID-19 cholangiopathy was reported in 30 cases during the study period. The mean (standard deviation [SD]) age was 53.7 (5). Men accounted for cases (83.3%). All patients had required intensive level of care and mechanical ventilation. Mean (SD) number of days from COVID infection to severe disease or liver disease was 63.5(38). Peak mean (SD) alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, total bilirubin were 2014 (831.8) U/L, 1555 (2432.8) U/L, 899.72 (1238.6) U/L, and 10.32 (9.32) mg/dl, respectively. Four patients successfully underwent liver transplantation.

CONCLUSION

Post COVID-19 cholangiopathy is a severe and progressive complication of COVID-19 infection. More research is needed to better understand the pathophysiology and best treatment approach. Clinicians should suspect post COVID-19 cholangiopathy in patients with cholestatic liver injury following COVID-19 infection.

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.

Association of COVID-19 vaccination before conception with maternal liver function during early pregnancy: a cohort study of 7745 Chinese pregnant women

Multicenter case series has reported patients with hepatic injury following COVID-19 vaccination, which raised concern for the possibility of vaccine-induced liver dysfunction. We aimed to assess the impact of COVID-19 vaccination on liver function of pregnant women, who may be uniquely susceptible to vaccine-induced liver dysfunction. We conducted a retrospective cohort study at a tertiary hospital in Shanghai, China. Vaccine administration was obtained from the electronic vaccination record. Serum levels of alanine transaminase (ALT), aspartate transaminase (AST), total bile acid (TBA) and total bilirubin (TBIL) in early pregnancy were determined by enzymatic methods. Among the 7745 included pregnant women, 3832 (49.5%) received at least two doses of an inactivated vaccine. COVID-19 vaccination was significantly associated with higher levels of maternal serum TBA. Compared with unvaccinated pregnant women, the mean TBA levels increased by 0.17 μmol/L (β = 0.17, 95% CI, 0.04, 0.31) for women who had been vaccinated within 3 months before the date of conception. Moreover, COVID-19 vaccination was significantly associated with an increased risk of maternal hyperbileacidemia. The risk of hyperbileacidemia increased by 113% (RR = 2.13; 95% CI, 1.17-3.87) for pregnant women who had been vaccinated within 3 months before conception compared with unvaccinated pregnant women. However, when the interval from complete vaccination to conception was prolonged to more than 3 months, COVID-19 vaccination was not associated with serum TBA levels or maternal hyperbileacidemia. Our findings suggest that vaccination with inactivated COVID-19 vaccines more than 3 months before conception have no detrimental effects on maternal liver function in early pregnancy.

Clerodendrum wallichii Merr Methanol Extract Protected Alcohol-Induced Liver Injury in Sprague-Dawley Rats by Modulating Antioxidant Enzymes

Materials and Methods

An oral acute toxicity study was carried out following OECD guidelines. Hepatotoxicity was induced by the administration of ethanol for 4 weeks. Hepatic enzymes and oxidative stress biomarkers were determined using commercial diagnostic kits.

Results

Treatment of rats with MECW (800 mg/kg) showed the highest reduction of body weight (4.76 ± 0.372 vs. 16.92 ± 0.846) and liver weight (3.06 ± 0.128 vs 5.55 ± 0.311). Treatment of rats with MECW at 200, 400, 600, 800, and 1000 mg/kg significantly (^∗∗p < 0.01) reduced SGPT. Similarly, serum SGOT and ALP were significantly decreased by MECW (200, 400, 600, 800, and 1000 mg/kg). All used doses of MECW significantly increased antioxidant enzymes GSH and SOD. MECW (600 and 800 mg/kg) significantly promoted CAT levels in liver tissues; whereas, it significantly diminished oxidative biomarker, MDA. Histopathological observations of the liver showed improvement in the architecture of hepatic cells having signs of protection with a reduced number of inflammatory cells, vascular degeneration and congestion, cellular degeneration, necrosis, and significant reduction of fatty cells accumulation. Acute toxicity study resulted in the well-tolerability and safety of used doses of MECW (200–1000 mg/kg) in rats.

Conclusion

Our study clearly demonstrated the hepatoprotective effect of Clerodendrum wallichii extract against ethanol-induced liver injury in the laboratory rats model.

Synthesis, Antiviral, and Antibacterial Activity of the Glycyrrhizic Acid and Glycyrrhetinic Acid Derivatives

Glycyrrhizic acid and its primary metabolite glycyrrhetinic acid, are the main active ingredients in the licorice roots (glycyrrhiza species), which are widely used in several countries of the world, especially in east asian countries (China, Japan). These ingredients and their derivatives play an important role in treating many diseases, especially infectious diseases such as COVID-19 and hepatic infections. This review aims to summarize the different ways of synthesising the amide derivatives of glycyrrhizic acid and the main ways to synthesize the glycyrrhitinic acid derivatives. Also, to determine the main biological and pharmacological activity for these compounds from the previous studies to provide essential data to researchers for future studies.

Supplementary Information

The online version contains supplementary material available at 10.1134/S1068162022050132.

Persistent Cholestatic Injury and Secondary Sclerosing Cholangitis in COVID-19 Patients

CONTEXT.–

Coronavirus disease 2019 (COVID-19) has been associated with liver injury, and a small subset of patients recovering from severe disease have shown persistent markedly elevated liver biochemistries for months after infection.

OBJECTIVE.–

To characterize persistent biliary injury after COVID-19.

DESIGN.–

A search of the pathology archives identified 7 post-COVID-19 patients with persistent biliary injury, and the clinical, radiologic, and pathologic features were assessed.

RESULTS.–

All patients in this cohort presented with respiratory symptoms and had a complicated clinical course with acute elevation of liver biochemistries. Alkaline phosphatase (ALP) was markedly and persistently elevated after discharge (median peak ALP: 1498 IU/L, at a median of 84 days from diagnosis). Magnetic resonance cholangiopancreatography (MRCP) showed 3 patients with irregularity, stricturing, and dilatation of intrahepatic ducts; no radiographic abnormalities were identified in the remaining 4 patients. Liver biopsies showed mild portal changes with features of cholestatic injury in 4 patients (bile duct injury and canalicular cholestasis) and marked biliary obstruction in 2 patients (profound cholestasis, ductular reaction, and bile infarcts), but no SARS-CoV-2 ribonucleic acid (RNA) was identified on in-situ hybridization. On follow-up, most patients had minimal intervention and showed marked improvement of liver biochemistries but with mild persistent elevation of ALP.

CONCLUSIONS.–

A subset of critically ill COVID-19 patients demonstrates marked and persistent cholestatic injury, with radiographic and histologic evidence of secondary sclerosing cholangitis, suggesting that cholestatic liver disease and secondary sclerosing cholangitis may be long-term sequelae of COVID-19 acute illness as a longstanding manifestation of critical illness.

Human Coronary Plaque T Cells Are Clonal and Cross-React to Virus and Self

BACKGROUND

Coronary artery disease is an incurable, life-threatening disease that was once considered primarily a disorder of lipid deposition. Coronary artery disease is now also characterized by chronic inflammation' notable for the buildup of atherosclerotic plaques containing immune cells in various states of activation and differentiation. Understanding how these immune cells contribute to disease progression may lead to the development of novel therapeutic strategies.

METHODS

We used single-cell technology and in vitro assays to interrogate the immune microenvironment of human coronary atherosclerotic plaque at different stages of maturity.

RESULTS

In addition to macrophages, we found a high proportion of αβ T cells in the coronary plaques. Most of these T cells lack high expression of CCR7 and L-selectin, indicating that they are primarily antigen-experienced memory cells. Notably, nearly one-third of these cells express the HLA-DRA surface marker, signifying activation through their TCRs (T-cell receptors). Consistent with this, TCR repertoire analysis confirmed the presence of activated αβ T cells (CD4<CD8), exhibiting clonal expansion of specific TCRs. Interestingly, we found that these plaque T cells had TCRs specific for influenza, coronavirus, and other viral epitopes, which share sequence homologies to proteins found on smooth muscle cells and endothelial cells, suggesting potential autoimmune-mediated T-cell activation in the absence of active infection. To better understand the potential function of these activated plaque T cells, we then interrogated their transcriptome at the single-cell level. Of the 3 T-cell phenotypic clusters with the highest expression of the activation marker HLA-DRA, 2 clusters expressed a proinflammatory and cytolytic signature characteristic of CD8 cells, while the other expressed AREG (amphiregulin), which promotes smooth muscle cell proliferation and fibrosis, and, thus, contributes to plaque progression.

CONCLUSIONS

Taken together, these findings demonstrate that plaque T cells are clonally expanded potentially by antigen engagement, are potentially reactive to self-epitopes, and may interact with smooth muscle cells and macrophages in the plaque microenvironment.

Evaluation of Liver Histopathological Findings of Coronavirus Disease 2019 by Minimally Invasive Autopsies

AIM

The severe acute respiratory syndrome coronavirus 2 outbreak resulted in severe health impact with the loss of many lives across the world. Pulmonary parenchyma suffers the most from the brunt of the infection. However, evidence suggested a systemic involvement during the course of illness. Information on morphological changes of the liver is sparse in the literature. We aimed to evaluate the pathological findings in the liver by minimally invasive autopsies.

METHODS

Postmortem core biopsies of the liver obtained from patients who succumbed to coronavirus disease 2019 disease were studied. Demographic findings, comorbidities, and relevant laboratory tests were collected. Detailed histopathological changes were assessed.

RESULTS

Liver function tests were available in 40 cases, and it was deranged in 80% cases. A spectrum of histological changes was observed. Macrovesicular steatosis and nonspecific portal inflammation of mild degree were the common morphological changes. Features suggestive of vascular alteration were noted in more than half of the cases. These included increased portal vein branches, irregular luminal dilation, and herniation of portal veins into the periportal hepatocytes. In addition, we observed morphological changes attributed to terminal shock-related changes.

CONCLUSION

The present study results highlight that liver parenchyma changes may be related to multiple pathogenic mechanisms. The presence of vascular alteration in portal tracts suggests derangement of hepatic vasculature related to systemic hypercoagulable state induced by the viral infection. It remains to be established if the histological changes are related to direct viral insult or to the systemic response caused by the viral attack.

COVID-19 and Preeclampsia: Overlapping Features in Pregnancy

Coronavirus disease 2019 (COVID-19) is a global respiratory disease with unique features that have placed all medical professionals in an alarming situation. Preeclampsia is a hypertensive disorder of pregnancy affecting 8%-10% of India's pregnant population. Assuming that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells through the angiotensin-converting enzyme 2 (ACE2) receptor, the resulting symptoms are due to vasoconstriction, caused by disturbances in the renin-angiotensin system (RAS). Other features of preeclampsia include endothelial dysfunction due to placental ischemia, leading to imbalances in angiogenic and antiangiogenic factors which result in increased blood pressure, proteinuria, altered hepatic enzymes, renal failure, and thrombocytopenia, amongst others. The increased prevalence of preeclampsia that was seen among mothers with SARS-CoV-2 infection might be due to misdiagnosis, as COVID-19 and preeclampsia have coincidental medical features. The major similarities of SARS-CoV-2-infected and preeclamptic women are a rise in pro-inflammatory cytokines, and increased serum ferritin and thrombocytopenia. Therefore, differential diagnosis might be difficult in pregnant women with COVID-19 who present with hypertension and proteinuria, thrombocytopenia, or elevated liver enzymes. The most promising markers for earlier diagnosis of preeclampsia is soluble endoglin (sEng), pregnancy-associated plasma protein-A (PAPP-A), soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF). Due to placental hypoxia, sFlt-1 will be overproduced, thus inhibiting PlGF, and this alteration will be observed in the circulation five weeks or more before the onset of symptoms. The sFlt-1/PlGF ratio may also be modified via infectious states, but unregulated levels of those mediators are related to placental insufficiency. Hence, pregnant women with COVID-19 may develop a preeclampsia-like syndrome that might be differentiated properly by angiogenic markers to avoid unnecessary interventions and induced preterm labor.

Liver Injury in Patients with COVID-19 without Underlying Liver Disease

SARS-CoV-2 shows a high affinity for the ACE-2 receptor, present on the epithelial cells of the upper and lower respiratory tract, within the intestine, kidneys, heart, testes, biliary epithelium, and-where it is particularly challenging-on vascular endothelial cells. Liver involvement is a rare manifestation of COVID-19.

MATERIAL AND METHODS

We reviewed 450 patients admitted due to the fact of SARS-CoV-2 infection (COVID-19) including 88 with liver injury. Based on medical history and previous laboratory test results, we excluded cases of underlying liver disease. The analysis involved a clinical course of COVID-19 in patients without underlying liver disease as well as the type and course of liver injury.

RESULTS

Signs and symptoms of liver injury were present in 20% of patients, mostly presenting as a mixed-type pattern of injury with less common cases of standalone hepatocellular (parenchymal) or cholestatic injury. The liver injury symptoms resolved at the end of inpatient treatment in 20% of cases. Sixteen patients died with no cases where liver injury would be deemed a cause of death.

CONCLUSIONS

(1) Liver injury secondary to COVID-19 was mild, and in in 20%, the signs and symptoms of liver injury resolved by the end of hospitalization. (2) It seems that liver injury in patients with COVID-19 was not associated with a higher risk of mortality. (3) The underlying mechanism of liver injury as well as its sequelae are not fully known. Therefore, caution and further monitoring are advised, especially in patients whose liver function tests have not returned to normal values.

Liver Injury in COVID-19: A Direct Hit or Collateral Damage?

SARS-CoV-2 is a novel coronavirus that has been identified, in December 2019, in Wuhan, China, and since it has become a worldwide pandemic, it has imposed far-reaching impacts on global human health and socio-economic activity. Worldwide, over 4 million Covid-19 related deaths were reported until September 2021. Recently published case studies have reported that Covid-19 patients develop different degrees of liver dysfunction. Inevitably, in hospitalized Covid-19 patients who develop acute liver derangement, there are a plethora of potential pathogenic causes such as direct-viral, immune-driven, and drug-induced and/or ischaemic liver injury. Patients with advanced chronic liver diseases (e.g., cirrhosis) and/or autoimmune liver disease have a poor immune function and associated poorer outcomes compared to other critically ill cohorts. However, largely any immediate liver derangement tends to be relatively mild, and as such, any de novo liver injury may not be a significant feature of Covid-19. There is an immediate necessity, therefore, to better understand the liver-specific pathophysiology of COVID-19. This review focuses on the up-to-date information regarding Covid-19 and associated indices for liver dysfunction, possible mechanisms, and potential drug targeted therapies in Covid-19 patients with and without liver dysfunction. PubMed database was used to perform an extensive literature search using the keywords liver and SARS-CoV-2, liver and Covid-19, Covid 19 and treatment, etc.

Intestinal virome and therapeutic potential of bacteriophages in liver disease

Humans harbour a large quantity of microbes in the intestinal tract and have evolved symbiotic relationships with many of them. However, several specific bacterial pathobionts are associated with liver disease pathogenesis. Although bacteriophages (phages) and eukaryotic viruses (collectively known as "the virome") outnumber bacteria and fungi in the intestine, little is known about the intestinal virome in patients with liver disease. As natural predators of bacteria, phages can precisely edit the bacterial microbiota. Hence, there is interest in using them to target bacterial pathobionts in several diseases, including those of the liver. Herein, we will summarise changes in the faecal virome associated with fatty liver diseases and cirrhosis, and describe the therapeutic potential of phages and potential challenges to their clinical application.

Immune dysregulation and system pathology in COVID-19

The coronavirus disease 19 (COVID-19) caused by the novel coronavirus known as SARS-CoV-2 has caused a global public health crisis. As of 7 January 2021, 87,640,402 confirmed cases and 1,891,692 mortalities have been reported worldwide. Studies focusing on the epidemiological and clinical characteristics of COVID-19 patients have suggested a dysregulated immune response characterized by lymphopenia and cytokine storm in these patients. The exaggerated immune response induced by the cytokine storm causes septic shock, acute respiratory distress syndrome (ARDS), and/or multiple organs failure, which increases the fatality rate of patients with SARS-CoV-2 infection. Herein, we review the recent research progress on epidemiology, clinical features, and system pathology in COVID-19. Moreover, we summarized the recent therapeutic strategies, which are either approved, under clinical trial, and/or under investigation by the local or global health authorities. We assume that treatments should focus on the use of antiviral drugs in combination with immunomodulators as well as treatment of the underlying comorbidities.

Impact of COVID-19 on liver disease: From the experimental to the clinic perspective

Coronavirus disease 2019 (COVID-19) has caused a global pandemic unprecedented in over a century. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a predominantly respiratory infection, various degrees of liver function abnormalities have been reported. Pre-existing liver disease in patients with SARS-CoV-2 infection has not been comprehensively evaluated in most studies, but it can critically compromise survival and trigger hepatic decompensation. The collapse of the healthcare services has negatively impacted the diagnosis, monitoring, and treatment of liver diseases in non-COVID-19 patients. In this review, we aim to discuss the impact of COVID-19 on liver disease from the experimental to the clinic perspective.

Comparison of different prognostic scores for patients with cirrhosis hospitalized with SARS-CoV-2 infection

INTRODUCTION AND OBJECTIVES

Viral infections have been described to increase the risk of decompensation in patients with cirrhosis. We aimed to determine the effect of SARS-CoV-2 infection on outcome of hospitalized patients with cirrhosis and to compare the performance of different prognostic models for predicting mortality.

PATIENTS

We performed a prospective cohort study including 2211 hospitalized patients with confirmed SARS-CoV-2 infection from April 15, 2020 through October 1, 2020 in 38 Hospitals from 11 Latin American countries. We registered clinical and laboratory parameters of patients with and without cirrhosis. All patients were followed until discharge or death. We evaluated the prognostic performance of different scoring systems to predict mortality in patients with cirrhosis using ROC curves.

RESULTS

Overall, 4.6% (CI 3.7-5.6) subjects had cirrhosis (n = 96). Baseline Child-Turcotte-Pugh (CTP) class was assessed: CTP-A (23%), CTP-B (45%) and CTP-C (32%); median MELD-Na score was 19 (IQR 14-25). Mortality was 47% in patients with cirrhosis and 16% in patients without cirrhosis (P < .0001). Cirrhosis was independently associated with death [OR 3.1 (CI 1.9-4.8); P < .0001], adjusted by age, gender, and body mass index >30. The areas under the ROC curves for performance evaluation in predicting 28-days mortality for Chronic Liver Failure Consortium (CLIF-C), North American Consortium for the Study of End-Stage Liver Disease (NACSELD), CTP score and MELD-Na were 0.85, 0.75, 0.69, 0.67; respectively (P < .0001).

CONCLUSIONS

SARS-CoV-2 infection is associated with elevated mortality in patients with cirrhosis. CLIF-C had better performance in predicting mortality than NACSELD, CTP and MELD-Na in patients with cirrhosis and SARS-CoV-2 infection. Clinicaltrials.gov:NCT04358380.

COVID-19 and Indirect Liver Injury: A Narrative Synthesis of the Evidence

The liver is frequently affected by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. The most common manifestations are mildly elevated alanine aminotransferase and aspartate aminotransferase, with a prevalence of 16-53% among patients. Cases with severe coronavirus disease 2019 (COVID-19) seem to have higher rates of acute liver dysfunction, and the presence of abnormal liver tests at admission signifies a higher risk of severe disease during hospitalization. Patients with chronic liver diseases also have a higher risk of severe disease and mortality (mainly seen in patients with metabolic-associated fatty liver disease). Several pathways of damage have been proposed in the liver involvement of COVID-19 patients; although, the end-cause is most likely multifactorial. Abnormal liver tests have been attributed to the expression of angiotensin-converting enzyme 2 receptors in SARS-CoV-2 infection. This enzyme is expressed widely in cholangiocytes and less in hepatocytes. Other factors attributed to liver damage include drug-induced liver injury, uncontrolled release of proinflammatory molecules ("cytokine storm"), pneumonia-associated hypoxia, and direct damage by the infection. Hepatic steatosis, vascular thrombosis, fibrosis, and inflammatory features (including Kupffer cell hyperplasia) are the most common liver histopathological findings in deceased COVID-19 patients, suggesting important indirect mechanisms of liver damage. In this translational medicine-based narrative review, we summarize the current data on the possible indirect mechanisms involved in liver damage due to COVID-19, the histopathological findings, and the impact of these mechanisms in patients with chronic liver disease.

Identifying longitudinal clusters of multimorbidity in an urban setting: A population-based cross-sectional study

Background

Globally, there is increasing research on clusters of multimorbidity, but few studies have investigated multimorbidity in urban contexts characterised by a young, multi-ethnic, deprived populations. This study identified clusters of associative multimorbidity in an urban setting.

Methods

This is a population-based retrospective cross-sectional study using electronic health records of all adults aged 18 years and over, registered between April 2005 to May 2020 in general practices in one inner London borough. Multiple correspondence analysis and cluster analysis was used to identify groups of multimorbidity from 32 long-term conditions (LTCs).

Results

The population included 41 general practices with 826,936 patients registered between 2005 and 2020, with mean age 40 (SD15·6) years. The prevalence of multimorbidity was 21% (n = 174,881), with the median number of conditions being three and increasing with age. Analysis identified five consistent LTC clusters: 1) anxiety and depression (Ratio of within- to between- sum of squares (WSS/BSS <0·01 to <0·01); 2) heart failure, atrial fibrillation, chronic kidney disease (CKD), chronic heart disease (CHD), stroke/transient ischaemic attack (TIA), peripheral arterial disease (PAD), dementia and osteoporosis (WSS/BSS 0·09 to 0·12); 3) osteoarthritis, cancer, chronic pain, hypertension and diabetes (0·05 to 0·06); 4) chronic liver disease and viral hepatitis (WSS/BSS 0·02 to 0·03); 5) substance dependency, alcohol dependency and HIV (WSS/BSS 0·37 to 0·55).

Interpretation

Mental health problems, pain, and at-risk behaviours leading to cardiovascular diseases are the important clusters identified in this young, urban population.

Funding

Impact on Urban Health, United Kingdom.

GalNAc-siRNA conjugates: Prospective tools on the frontier of anti-viral therapeutics

The growing use of short-interfering RNA (siRNA)-based therapeutics for viral diseases reflects the most recent innovations in anti-viral vaccines and drugs. These drugs play crucial roles in the fight against many hitherto incurable diseases, the causes, pathophysiologies, and molecular processes of which remain unknown. Targeted liver drug delivery systems are in clinical trials. The receptor-mediated endocytosis approach involving the abundant asialoglycoprotein receptors (ASGPRs) on the surfaces of liver cells show great promise. We here review N-acetylgalactosamine (GalNAc)-siRNA conjugates that treat viral diseases such as hepatitis B infection, but we also mention that novel, native conjugate-based, targeted siRNA anti-viral drugs may also cure several life-threatening diseases such as hemorrhagic cystitis, multifocal leukoencephalopathy, and severe acute respiratory syndrome caused by coronaviruses and human herpes virus.

Gastrointestinal Perspective of Coronavirus Disease 2019 in Children-An Updated Review

Gastrointestinal symptoms are common findings in children with severe acute respiratory syndrome coronavirus 2 infection, including vomiting, diarrhoea, abdominal pain, and difficulty in feeding, although these symptoms tend to be mild. The hepato-biliary system and the pancreas may also be involved, usually with a mild elevation of transaminases and, rarely, pancreatitis. In contrast, a late hyper-inflammatory phenomenon, termed multisystem inflammatory syndrome (MIS-C), is characterized by more frequent gastrointestinal manifestations with greater severity, sometimes presenting as peritonitis. Gastrointestinal and hepato-biliary manifestations are probably related to a loss in enterocyte absorption capability and microscopic mucosal damage caused by a viral infection of intestinal epithelial cells, hepatocytes and other cells through the angiotensin conversion enzyme 2 receptor resulting in immune cells activation with subsequent release of inflammatory cytokines. Specific conditions such as inflammatory bowel disease (IBD) and liver transplantation may pose a risk for the more severe presentation of coronavirus disease 2019 (COVID-19) but as adult data accumulate, paediatric data is still limited. The aim of this review is to summarize the current evidence about the effect of COVID-19 on the gastrointestinal system in children, with emphasis on the emerging MIS-C and specific considerations such as patients with IBD and liver transplant recipients.

Liver injury in patients with severe acute respiratory syndrome coronavirus-2 infection: a systematic review and meta-analysis

OBJECTIVE

Coronavirus disease-19 (COVID-19) infection is a global health threat. To inform the liver community on the potential relevance of COVID-19, we performed a systematic review and meta-analysis of published data on liver injury in patients with COVID-19 infection.

METHODS

We searched PubMed and Google Scholar through 22 March according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled data were analyzed by using random-effects meta-analyses.

RESULTS

A total of 14 studies combining data from 2.871 patients were identified. The prevalence of pre-existing liver disease was reported at 3.1%. The pooled prevalence of elevated aspartate aminotransferase (AST) and alanine transaminase (ALT) levels were 26% [95% confidence interval (CI), 20-32%] and 19% (95% CI, 14-26%), respectively. Only two studies reported the prevalence of elevated liver function tests according to normal ward versus ICU and here the frequency of elevated levels of AST was 50% and 62% versus ALT 40.8% and thus quantitatively higher in ICU-treated patients. Mean levels of absolute AST levels were 33 U/L (95% CI, 30.21-36.09), while mean ALT levels were 31 U/L (95% CI, 27.52-34.57). Cholestatic liver function tests were only incompletely reported in 510 patients. Here, mean levels of alkaline phosphatase were 71 U/L across three studies, and mean levels of gamma-glutamyl transferase were 40.6 U/L across four studies.

CONCLUSIONS

Emerging data on LFTs in COVID-19 are heterogeneous indicating mild LFTs involvement in every fourth to fifth patients with numerical more prevalent AST over ALT elevations. Prospective studies are needed to define the clinical relevance of liver injury in COVID-19.

Critical appraisal of the mechanisms of gastrointestinal and hepatobiliary infection by COVID-19

COVID-19 represents a novel infectious disease induced by SARS-CoV-2. It has to date affected 24,240,000 individuals and killed 2,735,805 people worldwide. The highly infectious virus attacks mainly the lung, causing fever, cough, and fatigue in symptomatic patients, but also pneumonia in severe cases. However, growing evidence highlights SARS-CoV-2-mediated extrarespiratory manifestations, namely, gastrointestinal (GI) and hepatic complications. The detection of 1) the virus in the GI system (duodenum, colon, rectum, anal region, and feces); 2) the high expression of additional candidate coreceptors/auxiliary proteins to facilitate the virus entry; 3) the abundant viral angiotensin-converting enzyme 2 receptor; 4) the substantial expression of host transmembrane serine protease 2, necessary to induce virus-cell fusion; 5) the viral replication in the intestinal epithelial cells; and 6) the primarily GI disorders in the absence of respiratory symptoms lead to increased awareness of the risk of disease transmission via the fecal-oral route. The objectives of this review are to provide a brief update of COVID-19 pathogenesis and prevalence, present a critical overview of its GI and liver complications that affect clinical COVID-19 outcomes, clarify associated mechanisms (notably microbiota-related), define whether gut/liver disorders occur more frequently among critically ill patients with COVID-19, determine the impact of COVID-19 on preexisting gut/liver complications and vice versa, and discuss the available strategies for prevention and treatment to improve prognosis of the patients. The novel SARS-CoV-2 can cause gastrointestinal and hepatobiliary manifestations. Metagenomics studies of virobiota in response to SARS-CoV-2 infection are necessary to highlight the contribution of bacterial microflora to COVID-19 phenotype, which is crucial for developing biomarkers and therapeutics.

Liver dysfunction and SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 infection is the cause of coronavirus disease 2019 (COVID-19), which predominantly affects the respiratory system; it also causes systemic and multi-organic disease. Liver damage is among the main extrapulmonary manifestations. COVID-19-associated liver injury is defined as any liver damage occurring during the disease course and treatment of COVID-19 in patients with or without pre-existing liver disease, and occurs in approximately one in five patients. Abnormal liver test results have been associated with a more severe course of COVID-19 and other complications, including death. Mechanisms linking COVID-19 to liver injury are diverse. Particular consideration should be made for patients with pre-existing liver disease, such as metabolic dysfunction-associated fatty liver disease, chronic liver disease due to viral or autoimmune disease, liver transplant carriers, or cirrhosis, given the risk for more severe outcomes. This manuscript summarizes the current lines of evidence on COVID-19-associated liver injury regarding pathophysiology, clinical significance, and management in both patients with or without pre-existing liver disease, to facilitate clinicians' access to updated information and patient care. Finally, we mention the ideas and recommendations to be considered for future research.

Patients with SARS-CoV-2 and HBV co-infection are at risk of greater liver injury

To date, it remains unclear if severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infection exacerbates liver injury in patients with chronic hepatitis B virus (HBV) infection. In this study, we present a retrospective study of 133 hospitalized confirmed mild coronavirus disease 2019 (COVID-19) cases, including 116 patients with COVID-19 with negative serum hepatitis B antigen and 17 HBV inactive carriers with COVID-19. We found that there were no significant differences for the discharge rate or duration of hospitalization between the two groups. However, inactive HBV carriers with SARS-CoV-2 co-infection are at a higher risk of abnormal liver function tests. The enhanced liver injury induced by SARS-CoV-2 and HBV co-infection was identified as the hepatocyte type rather than the cholangiocyte type. Moreover, the inflammatory response, including abnormal lactate dehydrogenase, D-dimer and interleukin-6 production, may contribute to this injury following SARS-CoV-2 co-infection. Collectively, SARS-CoV-2 and HBV co-infection exacerbates liver function of the patients with COVID-19.

Effect of COVID-19 on liver abnormalities: a systematic review and meta-analysis

Emerging evidence suggest association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with the development of many liver abnormalities. The overarching aim of this study was therefore to assess the available evidence on the clinical effects of SARS-CoV-2 on the profiles of liver chemistries and coagulation in COVID-19 diagnosed patients. We considered all study designs including epidemiological and observational that reported liver function test abnormalities in patients confirmed with SARS-CoV-2 infection. Medline, Embase databases and Google Scholar as well as relevant reviews were searched to identify appropriate studies from inception to 31st of August 2020. We calculated the pooled mean with 95% confidence intervals (95% CI) through a random-effect model meta-analysis. A total of 35 studies with 10,692 participants were considered for the review from which 23 studies with sufficient quantitative data were included in the meta-analysis. The pooled mean for liver enzymes and coagulation parameters did not significantly change in patients diagnosed with COVID-19 and remained within normal range. Notwithstanding potential bias from confounding factors in interpretation of data in this review, findings from the observational studies and case reports suggest that COVID-19 does not appear to have a significant impact on the transaminases or total bilirubin levels of patients with confirmed SARS-CoV-2 infection. Further controlled studies and larger sample size observational studies are needed with adequate reporting of other liver function parameters are warranted.