Association of metabolic dysfunction-associated fatty liver disease with gastrointestinal infections: insights from National Inpatient Sample Database

OBJECTIVES

The study aimed to compare the risk of gastrointestinal infections among patients with and without metabolic dysfunction-associated fatty liver disease (MAFLD).

METHODS

This was a population-based, retrospective, observational study using data from the National Inpatient Sample (NIS), the largest all-payer US inpatient care database.

SETTING

Hospitalisation of adults aged ≥18 years old admitted in 2020 was identified using the NIS. Patients were stratified by the presence and absence of MAFLD.

PARTICIPANTS

26.4 million adults aged ≥18 years old were included in the study. Patients younger than 18 and those with missing demographic or mortality data were excluded.

PRIMARY AND SECONDARY OUTCOMES

Primary outcome was to assess the overall risk of gastrointestinal infections in patients with and without MAFLD. Secondary outcomes were demographics and comorbidities stratified by the presence or absence of gastrointestinal infection, and the risk of specific gastrointestinal pathogens.

RESULTS

Of 26.4 million patients admitted in 2020, 755 910 (2.85%) had the presence of MAFLD. There was a higher prevalence of bacterial gastrointestinal infections in patients with MAFLD than those without (1.6% vs 0.9%, p<0.001). The incidence of Clostridioides difficile (1.3% vs 0.8%, p<0.001), Escherichia coli (0.3% vs 0.01%, p<0.001), and Salmonella (0.07% vs 0.03%, p<0.001) was higher in patients with MAFLD. The presence of MAFLD was associated with higher odds of developing gastrointestinal infections (adjusted OR (aOR) -1.75, 95% CI -1.68 to 1.83, p<0.001). After adjusting for confounders, results remained statistically significant (aOR -1.36, 95% CI - 1.30-1.42, p<0.001).

CONCLUSION

Even after adjusting for confounding factors, our study demonstrates an increased risk of gastrointestinal infections in patients with MAFLD, specifically of C. difficile, E. coli, and Salmonella. The immune and microbiota changes seen within MAFLD potentially contribute to the increased risk of gastrointestinal infections.

Defining the key intrahepatic gene networks in HCV infection driven by sex

OBJECTIVE

The transcriptional response in the liver during HCV infection is critical for determining clinical outcomes. This issue remains relatively unexplored as tissue access to address this at scale is usually limited. We aimed to profile the transcriptomics of HCV-infected livers to describe the expression networks involved and assess the effect on them of major predictors of clinical outcome such as IFNL4 (interferon lambda 4) host genotype and sex.

DESIGN

We took advantage of a large clinical study of HCV therapy accompanied by baseline liver biopsy to examine the drivers of transcription in tissue samples in 195 patients also genotyped genome-wide for host and viral single nucleotide polymorphisms. We addressed the role of host factors (disease status, sex, genotype, age) and viral factors (load, mutation) on transcriptional responses.

RESULTS

We observe key modules of transcription which can be impacted differentially by host and viral factors. Underlying cirrhotic state had the most substantial impact, even in a stable, compensated population. Notably, sex had a major impact on antiviral responses in concert with IL28B (interleukin 28B)/IFNL4 genotype, with stronger interferon and humoral responses in females. Males tended towards a dominant cellular immune response. In both sexes, there was a strong influence of the underlying host disease status and of specific viral mutations, and sex-specific expression quantitative trait loci were also observed.

CONCLUSION

These features help define the major influences on tissue responses in HCV infection, impacting on the response to treatment and with broader implications for responses in other sex-biased infections.

Can foodborne illness estimates from different countries be legitimately compared?: case study of rates in the UK compared with Australia, Canada and USA

OBJECTIVE

Mathematical models have gained traction when estimating cases of foodborne illness. Model structures vary due to differences in data availability. This begs the question as to whether differences in foodborne illness rates internationally are real or due to differences in modelling approaches.Difficulties in comparing illness rates have come into focus with COVID-19 infection rates being contrasted between countries. Furthermore, with post-EU Exit trade talks ongoing, being able to understand and compare foodborne illness rates internationally is a vital part of risk assessments related to trade in food commodities.

DESIGN

We compared foodborne illness estimates for the United Kingdom (UK) with those from Australia, Canada and the USA. We then undertook sensitivity analysis, by recreating the mathematical models used in each country, to understand the impact of some of the key differences in approach and to enable more like-for-like comparisons.

RESULTS

Published estimates of overall foodborne illness rates in the UK were lower than the other countries. However, when UK estimates were adjusted to a more like-for-like approach to the other countries, differences were smaller and often had overlapping credible intervals. When comparing rates by specific pathogens, there were fewer differences between countries. The few large differences found, such as virus rates in Canada, could at least partly be traced to methodological differences.

CONCLUSION

Foodborne illness estimation models are country specific, making international comparisons problematic. Some of the disparities in estimated rates between countries can be shown to be attributed to differences in methodology rather than real differences in risk.

Fungal dysbiosis in cirrhosis

OBJECTIVE

Cirrhotics have a high rate of infections, which are increasingly fungal or culture-negative in nature. While infected cirrhotics have bacterial dysbiosis, the role of fungi is unclear. We aimed to evaluate gut bacterial and fungal dysbiosis in cross-sectional and longitudinal analyses of outpatient and inpatient cirrhotics and prediction of hospitalisations.

METHODS

Cross-sectional: Age-matched controls, outpatients (with/without antibiotics) and hospitalised uninfected, culture-negative and culture-positive cirrhotics were included and followed for 90 days. Longitudinal: Three studies were conducted: (1) cirrhotics followed over 6 months, (2) outpatient cirrhotics administered antibiotics per standard of care for 5 days and (3) cirrhotics and controls administered omeprazole over 14 days. In all studies, stool bacterial/fungal profiles were analysed.

RESULTS

Cross-sectional: In 143 cirrhotics and 26 controls, bacterial and fungal diversities were significantly linked. Outpatients on antibiotics and patients with culture-positive infections had the lowest diversities. Bacterial and fungal correlations were complex in uninfected, outpatient and control groups but were markedly skewed in infected patients. 21% were admitted on 90-day follow-up. A lower Bacteroidetes/Ascomycota ratio was associated with lower hospitalisations. Longitudinal: Fungal and bacterial profiles were stable on follow-up (5 days and 6 months). After antibiotics, a significantly reduced bacterial and fungal diversity, higher Candida and lower autochthonous bacterial relative abundance were seen. After omeprazole, changes in bacterial diversity and composition were seen but fungal metrics remained stable.

CONCLUSION

There is a significant fungal dysbiosis in cirrhosis, which changes differentially with antibiotics and proton pump inhibitor use, but is otherwise stable over time. A combined bacterial-fungal dysbiosis metric, Bacteroidetes/Ascomycota ratio, can independently predict 90-day hospitalisations in patients with cirrhosis.

CLINICAL TRIAL NUMBER

NCT01458990.

Toxin-positive Clostridium difficile latently infect mouse colonies and protect against highly pathogenic C. difficile

OBJECTIVE

Clostridium difficile is a toxin-producing bacterium and a leading cause of antibiotic-associated disease. The ability of C. difficile to form spores and infect antibiotic-treated persons at low multiplicity of infection (MOI) underlies its large disease burden. However, C. difficile-induced disease might also result from long-harboured C. difficile that blooms in individuals administered antibiotics.

DESIGN

Mice purchased from multiple vendors and repeatedly testing negative for this pathogen by quantitative PCR bloomed C. difficile following antibiotic treatment. This endogenous C. difficile strain, herein termed LEM1, which formed spores and produced toxin, was compared with highly pathogenic C. difficile strain VPI10463.

RESULTS

Whole-genome sequencing revealed that LEM1 and VPI10463 shared 95% of their genes, including all known virulence genes. In contrast to VPI10463, LEM1 did not induce overt disease when administered to antibiotic-treated or germ-free mice, even at high doses. Rather, blooms of LEM1 correlated with survival following VPI10463 inoculation, and exogenous administration of LEM1 before or shortly following VPI10463 inoculation prevented C. difficile-induced death. Accordingly, despite similar growth properties in vitro, LEM1 strongly outcompeted VPI10463 in mice even at 100-fold lower inocula.

CONCLUSIONS

These results highlight the difficulty of determining whether individual cases of C. difficile infection resulted from a bloom of endogenous C. difficile or a new exposure to this pathogen. In addition to impacting the design of studies using mouse models of C. difficile-induced disease, this study identified, isolated and characterised an endogenous murine spore-forming C. difficile strain able to decrease colonisation, associated disease and death induced by a pathogenic C. difficile strain.

Induction of humoural and cellular immunity by immunisation with HCV particle vaccine in a non-human primate model

OBJECTIVE

Although HCV is a major cause of chronic liver disease worldwide, there is currently no prophylactic vaccine for this virus. Thus, the development of an HCV vaccine that can induce both humoural and cellular immunity is urgently needed. To create an effective HCV vaccine, we evaluated neutralising antibody induction and cellular immune responses following the immunisation of a non-human primate model with cell culture-generated HCV (HCVcc).

DESIGN

To accomplish this, 10 common marmosets were immunised with purified, inactivated HCVcc in combination with two different adjuvants: the classically used aluminum hydroxide (Alum) and the recently established adjuvant: CpG oligodeoxynucleotide (ODN) wrapped by schizophyllan (K3-SPG).

RESULTS

The coadministration of HCVcc with K3-SPG efficiently induced immune responses against HCV, as demonstrated by the production of antibodies with specific neutralising activity against chimaeric HCVcc with structural proteins from multiple HCV genotypes (1a, 1b, 2a and 3a). The induction of cellular immunity was also demonstrated by the production of interferon-γ mRNA in spleen cells following stimulation with the HCV core protein. These changes were not observed following immunisation with HCVcc/Alum preparation. No vaccination-related abnormalities were detected in any of the immunised animals.

CONCLUSIONS

The current preclinical study demonstrated that a vaccine included both HCVcc and K3-SPG induced humoural and cellular immunity in marmosets. Vaccination with this combination resulted in the production of antibodies exhibiting cross-neutralising activity against multiple HCV genotypes. Based on these findings, the vaccine created in this study represents a promising, potent and safe prophylactic option against HCV.

Suppression of interferon-mediated anti-HBV response by single CpG methylation in the 5'-UTR of TRIM22

OBJECTIVE

Interferons (IFNs) mediate direct antiviral activity. They play a crucial role in the early host immune response against viral infections. However, IFN therapy for HBV infection is less effective than for other viral infections.

DESIGN

We explored the cellular targets of HBV in response to IFNs using proteome-wide screening.

RESULTS

Using LC-MS/MS, we identified proteins downregulated and upregulated by IFN treatment in HBV X protein (HBx)-stable and control cells. We found several IFN-stimulated genes downregulated by HBx, including TRIM22, which is known as an antiretroviral protein. We demonstrated that HBx suppresses the transcription of TRIM22 through a single CpG methylation in its 5'-UTR, which further reduces the IFN regulatory factor-1 binding affinity, thereby suppressing the IFN-stimulated induction of TRIM22.

CONCLUSIONS

We verified our findings using a mouse model, primary human hepatocytes and human liver tissues. Our data elucidate a mechanism by which HBV evades the host innate immune system.

Ultrastructural organisation of HCV from the bloodstream of infected patients revealed by electron microscopy after specific immunocapture

OBJECTIVE

HCV particles are associated with very low-density lipoprotein components in chronically infected patients. These hybrid particles, or 'lipo-viro particles' (LVPs), are rich in triglycerides, and contain the viral RNA, the capsid protein, E1E2 envelope glycoproteins and apolipoproteins B and E. However, their specific ultrastructural organisation has yet to be determined. We developed a strategy for the preparation of any viral sample that preserves the native structure of the LVPs, facilitating their precise morphological characterisation.

DESIGN

Using a strategy based on the direct specific immunocapture of particles on transmission electron microscopy (TEM) grids, we characterised the precise morphology of the viral particle by TEM.

RESULTS

The LVP consists of a broad nucleocapsid surrounding an electron-dense centre, presumably containing the HCV genome. The nucleocapsid is surrounded by an irregular, detergent-sensitive crescent probably composed of lipids. Lipid content may determine particle size. These particles carry HCV E1E2, ApoB and ApoE, as shown in our immuno-EM analysis. Our results also suggest that these putative LVPs circulate in the serum of patients as part of a mixed population, including lipoprotein-like particles and complete viral particles.

CONCLUSIONS

Twenty-five years after the discovery of HCV, this study finally provides information about the precise morphological organisation of viral particles. It is truly remarkable that our TEM images fully confirm the ultrastructure of LVPs predicted by several authors, almost exclusively from the results of molecular biology studies.

Study of hepatitis E virus infection of genotype 1 and 3 in mice with humanised liver

OBJECTIVE

The hepatitis E virus (HEV) is responsible for approximately 20 million infections per year worldwide. Although most infected people can spontaneously clear an HEV infection, immune-compromised individuals may evolve towards chronicity. Chronic HEV infection can be cured using ribavirin, but viral isolates with low ribavirin sensitivity have recently been identified. Although some HEV isolates can be cultured in vitro, in vivo studies are essentially limited to primates and pigs. Since the use of these animals is hampered by financial, practical and/or ethical concerns, we evaluated if human liver chimeric mice could serve as an alternative.

DESIGN

Humanised mice were inoculated with different HEV-containing preparations.

RESULTS

Chronic HEV infection was observed after intrasplenic injection of cell culture-derived HEV, a filtered chimpanzee stool suspension and a patient-derived stool suspension. The viral load was significantly higher in the stool compared with the plasma. Overall, the viral titre in genotype 3-infected mice was lower than that in genotype 1-infected mice. Analysis of liver tissue of infected mice showed the presence of viral RNA and protein, and alterations in host gene expression. Intrasplenic injection of HEV-positive patient plasma and oral inoculation of filtered stool suspensions did not result in robust infection. Finally, we validated our model for the evaluation of novel antiviral compounds against HEV using ribavirin.

CONCLUSIONS

Human liver chimeric mice can be infected with HEV of different genotypes. This small animal model will be a valuable tool for the in vivo study of HEV infection and the evaluation of novel antiviral molecules.

Prolonged suppression of HBV in mice by a novel antibody that targets a unique epitope on hepatitis B surface antigen

OBJECTIVE

This study aimed to investigate the therapeutic potential of monoclonal antibody (mAb) against HBV as a novel treatment approach to chronic hepatitis B (CHB) in mouse models.

METHODS

Therapeutic effects of mAbs against various epitopes on viral surface protein were evaluated in mice mimicking persistent HBV infection. The immunological mechanisms of mAb-mediated viral clearance were systematically investigated.

RESULTS

Among 11 tested mAbs, a novel mAb E6F6 exhibited the most striking therapeutic effects in several HBV-persistent mice. Single-dose administration of E6F6 could profoundly suppress the levels of hepatitis B surface antigen (HBsAg) and HBV DNA for several weeks in HBV-transgenic mice. E6F6 regimen efficiently prevented initial HBV infection, and reduced viral dissemination from infected hepatocytes in human-liver-chimeric mice. E6F6-based immunotherapy facilitated the restoration of anti-HBV T-cell response in hydrodynamic injection (HDI)-based HBV carrier mice. Immunological analyses suggested that the Fcγ receptor-dependent phagocytosis plays a predominant role in E6F6-mediated viral suppression. Molecular analyses suggested that E6F6 recognises an evolutionarily conserved epitope (GPCK(R)TCT) and only forms a smaller antibody-viral particle immune complex with limited interparticle crosslinking when it binds to viral particles. This unique binding characteristic of E6F6 to HBV was possibly associated with its effective in vivo opsonophagocytosis for viral clearance.

CONCLUSIONS

These results provided new insight into understanding the therapeutic role and mechanism of antibody against persistent viral infection. The E6F6-like mAbs may provide a novel immunotherapeutic agent against human chronic HBV infection.

Chimeric antigen receptor (CAR)-engineered T cells redirected against hepatitis C virus (HCV) E2 glycoprotein

OBJECTIVE

The recent availability of novel antiviral drugs has raised new hope for a more effective treatment of hepatitis C virus (HCV) infection and its severe sequelae. However, in the case of non-responding or relapsing patients, alternative strategies are needed. To this end we have used chimeric antigen receptors (CARs), a very promising approach recently used in several clinical trials to redirect primary human T cells against different tumours. In particular, we designed the first CARs against HCV targeting the HCV/E2 glycoprotein (HCV/E2).

DESIGN

Anti-HCV/E2 CARs were composed of single-chain variable fragments (scFvs) obtained from a broadly cross-reactive and cross-neutralising human monoclonal antibody (mAb), e137, fused to the intracellular signalling motif of the costimulatory CD28 molecule and the CD3ζ domain. Activity of CAR-grafted T cells was evaluated in vitro against HCV/E2-transfected cells as well as hepatocytes infected with cell culture-derived HCV (HCVcc).

RESULTS

In this proof-of-concept study, retrovirus-transduced human T cells expressing anti-HCV/E2 CARs were endowed with specific antigen recognition accompanied by degranulation and secretion of proinflammatory and antiviral cytokines, such as interferon γ, interleukin 2 and tumour necrosis factor α. Moreover, CAR-grafted T cells were capable of lysing target cells of both hepatic and non-hepatic origin expressing on their surface the HCV/E2 glycoproteins of the most clinically relevant genotypes, including 1a, 1b, 2a, 3a, 4 and 5. Finally, and more importantly, they were capable of lysing HCVcc-infected hepatocytes.

CONCLUSIONS

Clearance of HCV-infected cells is a major therapeutic goal in chronic HCV infection, and adoptive transfer of anti-HCV/E2 CARs-grafted T cells represents a promising new therapeutic tool.

Travel health and pretravel preparation in the patient with inflammatory bowel disease

BACKGROUND AND AIMS

Foreign travel for people with inflammatory bowel disease (IBD) carries an increased risk of travel-related morbidity. There is limited research looking specifically at travel-associated health risks and travel preparation in patients with IBD. The aims of this study are to explore the experience of travel, pretravel preparation undertaken by the patient with IBD and examine IBD healthcare professionals' (HCP) confidence at providing travel advice and the content of that advice.

METHODS

A survey of patients with IBD attending an outpatient clinic with a separate online survey sent to IBD HCPs recruited using regional and international network databases.

RESULTS

A total of 132 patients with IBD, Crohn's disease (67/132, 51%), male (60/132, 45%) and 128 HCPs (IBD nurse specialist 113, 88%; IBD physician 15, 12%) completed the questionnaires. IBD affected travel to some extent in 62% (82/132) of patients, and 64% (84/132) had experienced an IBD flare, of whom 64% still travelled overseas during this time. Only 23% (31/132) travellers sought pretravel medical advice and 40% (53/132) obtained travel insurance. Forty-eight per cent of respondents on immunomodulator therapy were unaware of the need to avoid live vaccines. Twenty-seven per cent (34/128) of IBD HCPs are not confident at providing pretravel advice; vaccination advice (54%), obtaining travel insurance (61%) and healthcare abroad (78%) are the areas of most uncertainty.

CONCLUSIONS

Patients do not seek adequate pretravel advice and consultations for those who do are often deficient. The majority of IBD professionals are not confident to provide comprehensive travel advice. Greater IBD-specific travel education and awareness is needed for both patients with IBD and professionals.

Pitfalls in diagnosis and treatment of alveolar echinococcosis: a sentinel case series

Background

Alveolar echinococcosis (AE) is a neglected zoonosis presenting with focal liver lesions (FLL) with a wide range of imaging patterns resembling benign as well as malignant FLLs. Complementary serology and histopathology may be misleading.

Objective

The objective of our study is to highlight pitfalls leading to wrong diagnoses and harmful interventions in patients with AE.

Design

This retrospective sentinel case series analyses diagnostic and treatment data of patients with confirmed AE.

Results

80 patients treated between 1999 and 2014 were included in the study. In 26/80 patients treatment decisions were based on a wrong diagnosis. AE was mistaken for cystic echinococcosis (CE) in 12/26 patients followed by cholangiocellular carcinoma (CCA) in 5/26 patients; 61/80 patients had predominantly infiltrative liver lesions and 19/80 patients had a predominantly pseudocystic radiological presentation. Serology correctly differentiated between Echinococcus multilocularis and Echinococcus granulosus in 53/80 patients. Histopathology reports attributed the right Echinococcus species in 25/58 patients but failed to differentiate E. multilocularis from E. granulosus in 25/58 patients. Although contraindicated in AE 8/25 patients treated surgically had instillation of a protoscolicidal agent intraoperatively. One of the eight patients developed toxic cholangitis and liver failure and died 1 year after liver transplantation.

Conclusions

Misclassification of AE leads to a critical delay in growth inhibiting benzimidazole treatment, surgical overtreatment and bares the risk of liver failure if protoscolicidal agents are instilled in AE pseudocysts.