SARS-CoV-2 and the liver: clinical and immunological features in chronic liver disease

The global prevalence and impact of steatotic liver disease and viral infections: A systematic review and meta-analysis

BACKGROUND

Steatotic liver disease (SLD) affects ~30% of adults worldwide. The global population is continuously threatened by epidemic and endemic viral diseases. This study aims to thoroughly examine the interaction between SLD and major viral diseases.

METHODS

We systematically searched databases from inception to April 2, 2024, for observational studies recording viral-infected adult patients with eligible data on the presence of hepatic steatosis.

RESULTS

Six hundred thirty-six eligible studies were included in the analysis of SLD prevalence. Among patients with monoinfections, the highest SLD prevalence was observed in those infected with HCV at 49% (95% CI: 47%-51%), followed by SARS-CoV-2 (39%, 95% CI [34%-44%]), HIV (39%, 95% CI [33%-44%]), and HBV (36%, 95% CI [32%-40%]). Additionally, co-infections, such as HCV-HIV and HBV-HCV, exhibit even higher SLD prevalence. The prevalence of steatohepatitis is particularly high in HIV-infected (24%, 95% CI: 17%-30%) and HCV-infected (18%, 95% CI: 13%-24%) populations. The co-existence of SLD with viral infections was associated not only with the progression of liver disease but also with more severe outcomes of the infections and poorer responses to antiviral treatment. The combination of cardiometabolic risk factors and viral-associated and host factors contributes to the higher risk of SLD in viral-infected populations.

CONCLUSIONS

SLD is highly prevalent in viral-infected populations, and the reciprocal interactions between SLD and viral diseases exacerbate both conditions, leading to poorer patient outcomes in general.

Angiotensin-converting enzyme 2 and hepatic SARS-CoV-2 infection: Regulation, association, and therapeutic implications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells via the angiotensin-converting enzyme 2 (ACE2) receptor. Mounting evidence has indicated the presence of hepatic SARS-CoV-2 infection and liver injury in patients with coronavirus disease 2019 (COVID-19). Understanding the mechanisms of hepatic SARS-CoV-2 infection is crucial for addressing COVID-19-related liver pathology and developing targeted therapies. This editorial discusses the significance of ACE2 in hepatic SARS-CoV-2 infection, drawing on the research by Jacobs et al. Their findings indicate that hepatic ACE2 expression, frequency of hepatic SARS-CoV-2 infection, and severity of liver injury are elevated in patients with pre-existing chronic liver diseases. These data suggest that hepatic ACE2 could be a promising therapeutic target for COVID-19.

Impact of COVID-19 on preexisting comorbidities

COVID-19 is a highly contagious viral disease caused by SARS-CoV-2, leading to a tragic global pandemic, where it was ranked in 2020 as the third leading cause of death in the USA, causing approximately 375,000 deaths, following heart disease and cancer. The CDC reports that the risk of death increases with age and preexisting comorbidities such as such as hypertension, diabetes, respiratory system disease, and cardiovascular disease. this report will delineate and analyze the paramount comorbidities and their repercussions on individuals infected with SARS-CoV-2.

COVID-19 vaccine updates for people under different conditions

SARS-CoV-2 has caused global waves of infection since December 2019 and continues to persist today. The emergence of SARS-CoV-2 variants with strong immune evasion capabilities has compromised the effectiveness of existing vaccines against breakthrough infections. Therefore, it is important to determine the best utilization strategies for different demographic groups given the variety of vaccine options available. In this review, we will discuss the protective efficacy of vaccines during different stages of the epidemic and emphasize the importance of timely updates to target prevalent variants, which can significantly improve immune protection. While it is recognized that vaccine effectiveness may be lower in certain populations such as the elderly, individuals with chronic comorbidities (e.g., diabetes with poor blood glucose control, those on maintenance dialysis), or those who are immunocompromised compared to the general population, administering multiple doses can result in a strong protective immune response that outweighs potential risks. However, caution should be exercised when considering vaccines that might trigger an intense immune response in populations prone to inflammatory flare or other complications. In conclusion, individuals with special conditions require enhanced and more effective immunization strategies to prevent infection or reinfection, as well as to avoid the potential development of long COVID.

Impaired SARS-CoV-2-Specific CD8+ T Cells After Infection or Vaccination but Robust Hybrid T Cell Immunity in Patients with Multiple Myeloma

BACKGROUND

Multiple myeloma (MM) patients are at high risk of severe infections including COVID-19 due to an immune dysregulation affecting both innate and adaptive immune responses. However, our understanding of the immune responses to infection and vaccination in MM patients is limited. To gain more detailed insights into infection- and vaccine-elicited T cell immunity in MM, we studied the CD8+ T cell response on the single-epitope level in SARS-CoV-2 convalescent and mRNA-vaccinated MM patients.

METHODS

We compared peptide/MHC class I tetramer-enriched SARS-CoV-2-specific CD8+ T cells and antibody responses in MM patients (convalescent: n = 16, fully vaccinated: n = 5, vaccinated convalescent: n = 5) and healthy controls (HCs) (convalescent: n = 58, fully vaccinated: n = 7) either after infection with SARS-CoV-2 alone, complete mRNA vaccination or SARS-CoV-2 infection and single-shot mRNA vaccination (hybrid immunity).

RESULTS

MM patients have lower frequencies and a lower proportion of fully functional virus-specific CD8+ T cells compared to HCs, after both SARS-CoV-2 infection and vaccination. CD8+ T cell memory subset distribution in MM patients is skewed towards reduced frequencies of central memory (TCM) T cells and higher frequencies of effector memory 1 (TEM1) T cells. In contrast, the humoral immune response was comparable in both cohorts after viral clearance. Notably, CD8+ T cell frequencies as well as the humoral immune response were improved by a single dose of mRNA vaccine in convalescent MM patients.

CONCLUSIONS

MM patients have relative immunological deficiencies in SARS-CoV-2 immunity but benefit from hybrid immunity. These findings underline the relevance of vaccinations in this vulnerable patient group.

Cholesterol and Cholesterol-Lowering Medications in COVID-19-An Unresolved Matter

Infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cause coronavirus disease 2019 (COVID-19), a disease with very heterogeneous symptoms. Dyslipidaemia is prevalent in at least 20% of Europeans, and dyslipidaemia before SARS-CoV-2 infection increases the risk for severe COVID-19 and mortality by 139%. Many reports described reduced serum cholesterol levels in virus-infected patients, in particular in those with severe disease. The liver is the major organ for lipid homeostasis and hepatic dysfunction appears to occur in one in five patients infected with SARS-CoV-2. Thus, SARS-CoV-2 infection, COVID-19 disease severity and liver injury may be related to impaired cholesterol homeostasis. These observations prompted efforts to assess the therapeutic opportunities of cholesterol-lowering medications to reduce COVID-19 severity. The majority of studies implicate statins to have beneficial effects on disease severity and outcome in COVID-19. Proprotein convertase subtilisin/kexin type 9 (PCSK9) antibodies have also shown potential to protect against COVID-19. This review describes the relationship between systemic cholesterol levels, liver injury and COVID-19 disease severity. The potential effects of statins and PCSK9 in COVID-19 are summarised. Finally, the relationship between cholesterol and lung function, the first organ to be affected by SARS-CoV-2, is described.

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.

Association of liver function and prognosis in patients with severe fever with thrombocytopenia syndrome

OBJECTIVES

Severe fever with thrombocytopenia syndrome (SFTS) is an epidemic emerging infectious disease with high mortality rate. We investigated the association between liver injury and clinical outcomes in patients with SFTS.

METHODS

A total of 291 hospitalized SFTS patients were retrospectively included. Cox proportional hazards model was adopted to identify risk factors of fatal outcome and Kaplan-Meier curves were used to estimate cumulative risks.

RESULTS

60.1% of patients had liver injury at admission, and the median alanine transaminase, aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bilirubin (TBil) levels were 76.4 U/L, 152.3 U/L, 69.8 U/L and 9.9 μmol/L, respectively. Compared to survivors, non-survivors had higher levels of AST (253.0 U/L vs. 131.1 U/L, P < 0.001) and ALP (86.2 U/L vs. 67.9 U/L, P = 0.006), higher proportion of elevated ALP (20.0% vs. 4.4%, P < 0.001) and liver injury (78.5% vs. 54.9%, P = 0.001) at admission. The presence of liver injury (HR 2.049, P = 0.033) at admission was an independent risk factor of fatal outcome.

CONCLUSIONS

Liver injury was a common complication and was strongly associated with poor prognosis in SFTS patients. Liver function indicators should be closely monitored for SFTS patients.

COVID-19, Possible Hepatic Pathways and Alcohol Abuse-What Do We Know up to 2023?

The pandemic period due to coronavirus disease 2019 (COVID-19) revolutionized all possible areas of global health. Significant consequences were also related to diverse extrapulmonary manifestations of this pathology. The liver was found to be a relatively common organ, beyond the respiratory tract, affected by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Multiple studies revealed the essential role of chronic liver disease (CLD) in the general outcome of coronavirus infection. Present concerns in this field are related to the direct hepatic consequences caused by COVID-19 and pre-existing liver disorders as risk factors for the severe course of the infection. Which mechanism has a key role in this phenomenon-previously existing hepatic disorder or acute liver failure due to SARS-CoV-2-is still not fully clarified. Alcoholic liver disease (ALD) constitutes another not fully elucidated context of coronavirus infection. Should the toxic effects of ethanol or already developed liver cirrhosis and its consequences be perceived as a causative or triggering factor of hepatic impairment in COVID-19 patients? In the face of these discrepancies, we decided to summarize the role of the liver in the whole picture of coronavirus infection, paying special attention to ALD and focusing on the pathological pathways related to COVID-19, ethanol toxicity and liver cirrhosis.

Effects of COVID-19 on the Liver and Mortality in Patients with SARS-CoV-2 Pneumonia Caused by Delta and Non-Delta Variants: An Analysis in a Single Centre

The aim of this study was to ascertain patient characteristics, outcomes, and liver injuries in patients infected with different SARS-CoV-2 variants. Data from consecutive adult patients with severe/critical COVID-19 admitted to our hospital during the peak month of the Delta wave were compared to the ancestral, Alpha, and Omicron waves. The dataset of 551 hospitalized patients was similar in the Delta/non-Delta waves. At admission and discharge, the median aminotransferase levels were normal or slightly increased. During the Delta wave (172 vs. 379 non-Delta patients), more patients died (OR 1.69, 95%CI 1.09-2.56) or had liver injury at discharge (alanine aminotransferase, ALT ≥ 2 ULN) (OR 1.97, 95%CI 1.08-3.54). In-hospital mortality was associated with age, lung injury, intensive care unit admission, number of and cardiovascular comorbidities, diabetes, chronic kidney disease, and all inflammatory biomarkers. Serious liver injury at admission (ALT ≥ 5 × ULN) was significantly associated with in-hospital mortality (OR = 7.9, 95%CI 2-28.9). At discharge, drug-induced liver injury (DILI) was found in patients treated with remdesivir, ALT ≥ 2 ULN (OR = 2.62, 95%CI 1.22-5.75). Treatment with dexamethasone, remdesivir, and immunomodulators showed improved survival, OR = 0.50 (95%CI 0.33-0.77). Regardless of the variant and treatment options, less than 2% of patients displayed serious liver injury, which was not found to be a death predictor in multivariable analysis.

COVID-19 vaccine effectiveness against hospitalisation and death of people in clinical risk groups during the Delta variant period: English primary care network cohort study

BACKGROUND

COVID-19 vaccines have been shown to be highly effective against hospitalisation and death following COVID-19 infection. COVID-19 vaccine effectiveness estimates against severe endpoints among individuals with clinical conditions that place them at increased risk of critical disease are limited.

METHODS

We used English primary care medical record data from the Oxford-Royal College of General Practitioners Research and Surveillance Centre sentinel network (N > 18 million). Data were linked to the National Immunisation Management Service database, Second Generation Surveillance System for virology test data, Hospital Episode Statistics, and death registry data. We estimated adjusted vaccine effectiveness (aVE) against COVID-19 infection followed by hospitalisation and death among individuals in specific clinical risk groups using a cohort design during the delta-dominant period. We also report mortality statistics and results from our antibody surveillance in this population.

FINDINGS

aVE against severe endpoints was high, 14-69d following a third dose aVE was 96.4% (95.1%-97.4%) and 97.9% (97.2%-98.4%) for clinically vulnerable people given a Vaxzevria and Comirnaty primary course respectively. Lower aVE was observed in the immunosuppressed group: 88.6% (79.1%-93.8%) and 91.9% (85.9%-95.4%) for Vaxzevria and Comirnaty respectively. Antibody levels were significantly lower among the immunosuppressed group than those not in this risk group across all vaccination types and doses. The standardised case fatality rate within 28 days of a positive test was 3.9/1000 in people not in risk groups, compared to 12.8/1000 in clinical risk groups. Waning aVE with time since 2nd dose was also demonstrated, for example, Comirnaty aVE against hospitalisation reduced from 96.0% (95.1-96.7%) 14-69days post-dose 2-82.9% (81.4-84.2%) 182days+ post-dose 2.

INTERPRETATION

In all clinical risk groups high levels of vaccine effectiveness against severe endpoints were seen. Reduced vaccine effectiveness was noted among the immunosuppressed group.