Prevalence of Nonalcoholic Fatty Liver Disease in Patients With Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Sheng-Jiang powder ameliorates NAFLD via regulating intestinal microbiota in mice

Background

Intestinal microbiota have been demonstrated to be involved in the development of NAFLD, while the relationship between the severity of NAFLD and intestinal microbiota is still not fully elucidated. Sheng-Jiang Powder (SJP) showed exact efficacy in treating SFL and great potential in regulating intestinal microbiota, but the effects need to be further addressed in NASH and liver fibrosis.

Objectives

To investigate the differences in intestinal microbiota of NAFLD with different severity and the effect of SJP on liver damage and intestinal microbiota.

Design

NAFLD mice models with different severity were induced by high-fat diet (HFD) or choline-deficient, L-amino acid-defined high-fat diet (CDAHFD) feeding and then treated with SJP/normal saline.

Methods

Biochemical blood tests, H&E/Masson/Oil Red O/IHC staining, Western blot, and 16SrDNA sequencing were performed to explore intestinal microbiota alteration in different NAFLD models and the effect of SJP on liver damage and intestinal microbiota.

Results

Intestinal microbiota alteration was detected in all NAFLD mice. SJP induced increased expression of Pparγ and alleviated liver lipid deposition in all NAFLD mice. Microbiome analysis revealed obvious changes in intestinal microbiota composition, while SJP significantly elevated the relative abundance of Roseburia and Akkermansia, which were demonstrated to be beneficial for improving inflammation and intestinal barrier function.

Conclusion

Our results demonstrated that SJP was effective in improving lipid metabolism in NAFLD mice, especially in mice with SFL. The potential mechanism may be associated with the regulation of intestinal microbiota.

NAFLD Is Associated With Quiescent Rather Than Active Crohn's Disease

BACKGROUND AND AIMS

Crohn's disease (CD) confers an increased risk of nonalcoholic fatty liver disease (NAFLD), but the pathogenesis remains poorly understood. We determined if active intestinal inflammation increases the risk of NAFLD in patients with CD.

METHODS

Two cohorts (2017/2018 and 2020) with CD and no known liver disease were enrolled consecutively during staging magnetic resonance enterography. We quantified proton density fat fraction, MaRIA (Magnetic Resonance Index of Activity), and visceral adipose tissue. NAFLD was diagnosed when proton density fat fraction ≥5.5%. Synchronous endoscopy was graded by the Simple Endoscopic Score for CD and Rutgeerts score, while clinical activity was graded by the Harvey-Bradshaw index. Cytokine profiling was performed for the 2020 cohort. Transient elastography and liver biopsy were requested by standard of care.

RESULTS

NAFLD was diagnosed in 40% (n = 144 of 363), with higher prevalence during radiographically quiescent disease (odds ratio, 1.7; P = .01), independent of body mass index/visceral adipose tissue (adjusted odds ratio, 7.8; P = .03). These findings were corroborated by endoscopic disease activity, but not by aggregate clinical symptoms. Circulating interleukin-8 was independent of body mass index to predict NAFLD, but traditional proinflammatory cytokines were not. NAFLD subjects had similar liver stiffness estimates regardless of CD activity. Definitive or borderline steatohepatitis was present in most patients that underwent liver biopsy.

CONCLUSIONS

Quiescent CD is associated with risk of NAFLD. These findings suggest potentially distinct pathogenic mechanisms of NAFLD in patients with CD compared with the prevailing leaky gut hypothesis proposed for individuals without inflammatory bowel disease. Future validation and mechanistic studies are needed to dissect these distinct disease modifying factors.

Ileitis promotes MASLD progression via bile acid modulation and enhanced TGR5 signaling in ileal CD8+ T cells

BACKGROUND & AIMS

Clinical evidence substantiates a link between inflammatory bowel disease, particularly Crohn's disease (CD), and metabolic dysfunction-associated steatotic liver disease (MASLD). This study aims to explore the underlying molecular mechanisms responsible for this association.

METHODS

MASLD was induced by administering high-fat and western diets, while inflammatory bowel disease was induced using DSS (dextran sulfate sodium) and the Il10 knockout (KO) mouse model. The investigation into the role of secondary bile acids (SBAs) in ileitis involved employing metagenomic sequencing, conducting metabolomics detection, performing fecal microbiota transplantation, and constructing CD8+ T cell-specific gene knockout mice.

RESULTS

In MASLD+DSS and Il10 KO MASLD mice, we observed ileitis characterized by T-cell infiltration and activation in the terminal ileum. This condition resulted in decreased bile acid levels in the portal vein and liver, inhibited hepatic farnesoid X receptor (FXR) activation, and exacerbated MASLD. Metagenomic and metabolomic analysis of ileal contents revealed increased Clostridium proliferation and elevated SBA levels in MASLD-associated ileitis. Experiments using germ-free mice and fecal microbiota transplantation suggested an association between SBA and MASLD-related ileitis. In vitro, SBAs promoted CD8+ T-cell activation via the TGR5, mTOR, and oxidative phosphorylation pathways. In vivo, TGR5 KO in CD8+ T cells effectively alleviated ileitis and reversed the MASLD phenotype. Clinical data further supported these findings, demonstrating a positive correlation between ileitis and MASLD.

CONCLUSION

MASLD-induced changes in intestinal flora result in elevated levels of SBAs in the ileum. In the presence of a compromised intestinal barrier, this leads to severe CD8+ T cell-mediated ileitis through the TGR5/mTOR/oxidative phosphorylation signaling pathway. Ileitis-induced tissue damage impairs enterohepatic circulation, inhibits hepatic FXR activation, and exacerbates the MASLD phenotype.

IMPACT AND IMPLICATIONS

Our study provides a comprehensive investigation of the interplay and underlying mechanisms connecting ileitis and metabolic dysfunction-associated steatotic liver disease (MASLD). Secondary bile acids produced by intestinal bacteria act as the critical link between MASLD and ileitis. Secondary bile acids exert their influence by disrupting liver lipid metabolism through the promotion of CD8+ T cell-mediated ileitis. In future endeavors to prevent and treat MASLD, it is essential to thoroughly account for the impact of the intestinal tract, especially the ileum, on liver function via the enterohepatic circulation.

Independent Associations of Aortic Calcification with Cirrhosis and Liver Related Mortality in Veterans with Chronic Liver Disease

INTRODUCTION

Abdominal aortic calcifications (AAC) are incidentally found on medical imaging and useful cardiovascular burden approximations. The Morphomic Aortic Calcification Score (MAC) leverages automated deep learning methods to quantify and score AACs. While associations of AAC and non-alcoholic fatty liver disease (NAFLD) have been described, relationships of AAC with other liver diseases and clinical outcome are sparse. This study's purpose was to evaluate AAC and liver-related death in a cohort of Veterans with chronic liver disease (CLD).

METHODS

We utilized the VISN 10 CLD cohort, a regional cohort of Veterans with the three forms of CLD: NAFLD, hepatitis C (HCV), alcohol-associated (ETOH), seen between 2008 and 2014, with abdominal CT scans (n = 3604). Associations between MAC and cirrhosis development, liver decompensation, liver-related death, and overall death were evaluated with Cox proportional hazard models.

RESULTS

The full cohort demonstrated strong associations of MAC and cirrhosis after adjustment: HR 2.13 (95% CI 1.63, 2.78), decompensation HR 2.19 (95% CI 1.60, 3.02), liver-related death HR 2.13 (95% CI 1.46, 3.11), and overall death HR 1.47 (95% CI 1.27, 1.71). These associations seemed to be driven by the non-NAFLD groups for decompensation and liver-related death [HR 2.80 (95% CI 1.52, 5.17; HR 2.34 (95% CI 1.14, 4.83), respectively].

DISCUSSION

MAC was strongly and independently associated with cirrhosis, liver decompensation, liver-related death, and overall death. Surprisingly, stratification results demonstrated comparable or stronger associations among those with non-NAFLD etiology. These findings suggest abdominal aortic calcification may predict liver disease severity and clinical outcomes in patients with CLD.

Neither hepatic steatosis nor fibrosis is associated with clinical outcomes in patients with intestinal Behçet's disease

BACKGROUND

Behçet's disease (BD) and nonalcoholic fatty liver disease (NAFLD) are chronic inflammatory diseases that share pathogenetic mechanisms. In this study, we investigated whether NAFLD influences the clinical outcomes in patients with intestinal BD.

METHODS

Patients with intestinal BD and available hepatic steatosis index (HSI) and fibrosis-4 (FIB-4) scores were recruited between 2005 and 2022. An HSI of ≥30 and FIB-4 of ≥1.45 were used to diagnose hepatic steatosis and significant liver fibrosis, respectively. The primary outcomes were intestinal BD-related hospitalization, surgery, emergency room visits, or the first use of corticosteroids, immunomodulators, or biologic agents for intestinal BD.

RESULTS

A total of 780 patients with BD were selected. The prevalence of hepatic steatosis and significant liver fibrosis were 72.3% and 8.8%, respectively. Multivariate analysis showed that younger age, prior smoking history, concomitant skin lesions, higher white blood cell count, and lower serum albumin levels were independently associated with an increased risk of clinical relapse (all P < 0.05), whereas hepatic steatosis and significant liver fibrosis were not (hazard ratio [HR] = 1.164, 95% confidence interval [CI] 0.923-1.468; P = 0.199 for hepatic steatosis; HR = 0.982, 95% CI 0.672-1.436; P = 0.927 for significant liver fibrosis).

CONCLUSION

Hepatic steatosis and liver fibrotic burden were not independently associated with clinical outcomes in patients with intestinal BD.

Hepatic Steatosis but Not Fibrosis Is Independently Associated with Poor Outcomes in Patients with Inflammatory Bowel Disease

Background/Aims

Increased prevalence of nonalcoholic fatty liver disease (NAFLD) and inflammatory bowel disease (IBD) has been reported. However, the effects of NAFLD on the outcome of IBD remains unclear. We investigated whether the presence of NAFLD could influence the outcomes of patients with IBD.

Methods

We recruited 3,356 eligible patients with IBD into our study between November 2005 and November 2020. Hepatic steatosis and fibrosis were diagnosed using hepatic steatosis index of ≥30 and fibrosis-4 of ≥1.45, respectively. The primary outcome was clinical relapse, defined based on the following: IBD-related admission, surgery, or first use of corticosteroids, immunomodulators, or biologic agents for IBD.

Results

The prevalence of NAFLD in patients with IBD was 16.7%. Patients with hepatic steatosis and advanced fibrosis were older, had a higher body mass index, and were more likely to have diabetes (all p<0.05).

Conclusions

Hepatic steatosis was independently associated with increased risks of clinical relapse in patients with ulcerative colitis and Crohn's disease, whereas fibrotic burden in the liver was not. Future studies should investigate whether assessment and therapeutic intervention for NAFLD will improve the clinical outcomes of patients with IBD.

Prevalence of Hepatobiliary Manifestations in Inflammatory Bowel Disease: A GRADE Assessed Systematic Review and Meta-Analysis of more than 1.7 Million Patients

BACKGROUND AND AIMS

Inflammatory bowel disease [IBD] comprises an immune-mediated group of chronic gastrointestinal disorders. Patients with IBD may experience extraintestinal manifestations, such as hepatobiliary complications. This meta-analysis aims to assess the prevalence of different hepatic manifestations in IBD patients.

METHODS

For this systematic review and meta-analysis, PubMed, Scopus, Web of Science, and Embase were searched until July 20, 2022, by specifying keywords for IBD, hepatic manifestations, and study type. Full texts of cohort studies in English that examined the prevalence of different hepatic manifestations were included in this study. The primary outcome was the overall prevalence of hepatic manifestations in IBD patients. For the statistical analysis, a proportion by random effect model meta-analysis was performed. The registration number for the protocol of this study in PROSPERO is CRD42022369595.

RESULTS

From the 4421 articles retrieved from the primary search, 118 met the inclusion criteria and were included in the final analysis. After a pooled analysis of 1 729 128 patients, the overall prevalence of hepatic manifestations was 3.49% (95% confidence interval [CI]: 3.31-3.68%; I2: 99.55%). The pooled prevalence of non-alcoholic fatty liver disease in 228 216 patients was 26.1% [95% CI: 22.1-30.2%; I2: 99.018%]. After pooled analysis of 9642 patients, the prevalence of primary sclerosing cholangitis was 1.67% [95% CI: 1.47-1.88%; I2: 99.10%]. The pooled prevalence of biliary stones was 4.1% [95% CI: 3.6-4.7%; I2: 97.43%]. Autoimmune hepatitis (0.51% [95% CI: 0.26-0.75%]; I2: 85.36%) and portal vein thrombosis (0.21% [95% CI: 0.08-0.33%]; I2: 97.95%) are considered as rare manifestations.

CONCLUSION

This study summarizes the prevalence and importance of different hepatic manifestations in IBD patients. These findings are crucial for the management of extraintestinal manifestations, especially hepatic manifestations, in IBD patients.

Identifying inflammatory bowel disease patients at risk of metabolic dysfunction-associated fatty liver disease: usefulness of non-invasive steatosis predictive scores

BACKGROUND

Inflammatory bowel disease (IBD) patients have a higher risk of metabolic dysfunction-associated fatty liver disease (MAFLD) compared with the general population. However, it is not known whether available non-invasive hepatic steatosis scores are useful in predicting MAFLD in IBD patients. We aimed to analyze the performances of MAFLD screening score (MAFLD-S), Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI) and Clinical Prediction Tool for NAFLD in Crohn's Disease (CPN-CD), in identifying MAFLD in IBD patients.

METHODS

A cross-sectional study was carried out including consecutive adult IBD outpatients submitted to transient elastography (TE). MAFLD criteria were assessed, and hepatic steatosis (HS) was defined by a controlled attenuation parameter (CAP) >248 dB/m using TE. MAFLD-S, FLI, HSI, and CPN-CD were calculated and their accuracy for the prediction of MAFLD was evaluated through their areas under the receiver-operating characteristic (AUROC) curves.

RESULTS

Of 168 patients, body mass index ≥25, type 2 diabetes mellitus, dyslipidemia and arterial hypertension were present in 76 (45.2%), 10 (6.0%), 53 (31.5%), 20 (11.9%), respectively. HS was identified in 77 (45.8%) patients, of which 65 (84.4%) fulfilled MAFLD criteria. MAFLD-S (AUROC, 0.929 [95% CI, 0.888-0.971]) had outstanding and FLI (AUROC, 0.882 [95% CI, 0.830-0.934]), HSI (AUROC, 0.803 [95% CI, 0.736-0.871]), and CPN-CD (AUROC, 0.822 [95% CI, 0.753-0.890) had excellent discrimination in predicting MAFLD.

CONCLUSIONS

MAFLD-S, FLI, HSI and CPN-CD scores can accurately identify MAFLD in IBD patients, allowing the selection of those in whom hepatic steatosis and metabolic risk factors assessment may be particularly beneficial.

Ultrasound Prevalence and Clinical Features of Nonalcoholic Fatty Liver Disease in Patients with Inflammatory Bowel Diseases: A Real-Life Cross-Sectional Study

Background and Objectives: Inflammatory bowel disease (IBD) is a condition characterized by chronic intestinal inflammation. We can identify two major forms: Crohn's disease (CD) and ulcerative colitis (UC). One of the extraintestinal manifestations of IBD is nonalcoholic fatty liver disease (NAFLD). IBD and NAFLD share common pathogenetic mechanisms. Ultrasound (US) examination is the most commonly used imaging method for the diagnosis of NAFLD. This cross-sectional observational retrospective study aimed to evaluate the US prevalence of NAFLD in IBD patients and their clinical features. Materials and Methods: A total of 143 patients with IBD underwent hepatic US and were divided into two different groups according to the presence or absence of NAFLD. Subsequently, new exclusion criteria for dysmetabolic comorbidities (defined as plus) were applied. Results: The US prevalence of NAFLD was 23% (21% in CD and 24% in UC, respectively). Most IBD-NAFLD patients were male and older and showed significantly higher values for body mass index, waist circumference, disease duration, and age at onset than those without NAFLD. IBD-NAFLD patients showed a significantly higher percentage of stenosing phenotype and left-side colitis. Regarding metabolic features, IBD-NAFLD patients showed a significantly higher percentage of hypertension and IBD plus dysmetabolic criteria. Also, higher values of alanine aminotransferase and triglycerides and lower levels of high-density lipoproteins are reported in these patients. Conclusions: We suggest performing liver US screening in subjects affected by IBD to detect NAFLD earlier. Also, patients with NAFLD present several metabolic comorbidities that would fall within the new definition of metabolic-associated fatty liver disease. Finally, we encourage larger longitudinal studies, including healthy controls, to provide further confirmation of our preliminary data.

Influence of nonalcoholic fatty liver disease on inflammatory bowel disease hospitalizations in the United States

Background

The reported prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with inflammatory bowel disease (IBD) is 32%. We assessed the influence of NAFLD on IBD hospitalizations in the United States (US).

Methods

We utilized the National Inpatient Sample database, from 2016-2019, to identify the total IBD hospitalizations in the US and we further subdivided them according to the presence or absence of NAFLD. Hospitalization characteristics, comorbidities and outcomes were compared. Statistical significance was set at P<0.05.

Results

There were 1,272,260 IBD hospitalizations in the US, of which 5.04% involved NAFLD. For IBD hospitalizations with NAFLD, the mean age was 50-64 years, and the proportion of males was 46.97%. IBD hospitalizations with NAFLD had a lower proportion of African Americans (8.7% vs. 11.38%, P<0.001). Comorbidities such as hypertension (50.34% vs. 44.04%, P<0.001) and obesity (18.77% vs. 11.81%, P<0.001) were significantly higher in the NAFLD cohort. Overall, based on the Charlson Comorbidity Index, patients with NAFLD had a higher number of comorbidities (52.77% vs. 20.66%, P<0.001). Mortality was higher in the NAFLD compared to the non-NAFLD cohort (3.14% vs. 1.44%, P<0.001). Patients with NAFLD also incurred significantly higher hospital charges ($69,536 vs. $55,467, p<0.001) and had a longer mean length of stay (6.10 vs. 5.27 days, P<0.001) compared to the cohort without NAFLD. Complications and inpatient procedure requirements were also higher in the NAFLD cohort.

Conclusion

Our study revealed greater mortality, morbidity, and healthcare resource utilization in patients with IBD who were hospitalized with a concomitant diagnosis of NAFLD.

Dextran sulfate sodium-induced gut microbiota dysbiosis aggravates liver injury in mice with S100-induced autoimmune hepatitis

Recently, the incidence of autoimmune hepatitis (AIH) has gradually increased, and the disease can eventually develop into cirrhosis or even hepatoma if left untreated. AIH patients are often characterized by gut microbiota dysbiosis, but whether gut microbiota dysbiosis contributes to the progression of AIH remains unclear. In this study, we investigate the role of gut microbiota dysbiosis in the occurrence and development of AIH in mice with dextran sulfate sodium salt (DSS) induced colitis. C57BL/6J mice were randomly divided into normal group, S100-induced AIH group, and DSS+S100 group (1 % DSS in the drinking water), and the experimental cycle lasted for four weeks. We demonstrate that DSS administration aggravates hepatic inflammation and disruption of the intestinal barrier, and significantly changes the composition of gut microbiota in S100-induced AIH mice, which are mainly characterized by increased abundance of pathogenic bacteria and decreased abundance of beneficial bacteria. These results suggest that DSS administration aggravates liver injury of S100-induced AIH, which may be due to DSS induced gut microbiota dysbiosis, leading to disruption of the intestinal barrier, and then, the microbiota translocate to the liver, aggravating hepatic inflammation.

Shared biomarkers and immune cell infiltration signatures in ulcerative colitis and nonalcoholic steatohepatitis

The coexistence of ulcerative colitis (UC) and nonalcoholic steatohepatitis (NASH) involves a intricate interplay, though the precise pathophysiological mechanisms remain elusive. To shed light on this, our study endeavors to unravel the shared gene signatures and molecular mechanisms by employing quantitative bioinformatics analysis on a publicly available RNA-sequencing database. Gene expression profiles of UC (GSE87466) and NASH (GSE89632) were retrieved from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were analyzed using R software. After identifying common DEGs, functional enrichment analysis, protein-protein interaction (PPI) network analysis and module construction were performed to obtain candidate hub genes. GSE47908 for UC and GSE159676 for NASH were selected to validate the obtained candidate genes. A total of 119 common DEGs were found in NASH and UC patients. Functional and pathway analyses emphasized that viral infection, inflammation and immune response were enriched in these two diseases. After module construction and validation, CD2, CD8A, GNLY, IFI44, NKG7 and OAS2 were identified as hub genes. 6 hub genes and their combined prediction scores were found with an impressive accuracy and sensitivity. Functional estimation, gene set enrichment analysis and immune infiltration signature identification showed notable associations of the six hub genes with T cells, natural killer cells and type I interferon levels. In addition, we constructed UC combined with NASH mice model successfully with significantly higher expression of hub genes in both liver and colonic tissues than those in control group. Our study elucidates 6 hub genes of UC and NASH, which may participate in immune, inflammatory and antiviral effects. These findings provide some potential biochemical markers for further exploration of UC coexistence with NASH.

Systematic Review and Meta-Analysis: Prevalence of Non-Alcoholic Fatty Liver Disease and Liver Fibrosis in Patients with Inflammatory Bowel Disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common concomitant condition in patients with inflammatory bowel disease (IBD). We aim to assess the magnitude of this association.

METHODS

We searched MEDLINE, EMBASE and Scopus libraries for the period up to February 2023 to identify studies reporting cohorts of IBD patients in which NALFLD was evaluated.

RESULTS

Eighty-nine studies were analyzed. The overall prevalence of NAFLD was 24.4% (95%CI, 19.3-29.8) in IBD, 20.2% (18.3-22.3) in Crohn's disease and 18.5% (16.4-20.8) for ulcerative colitis. Higher prevalence was found in male compared to female patients, in full papers compared to abstracts, and in cross-sectional studies compared to prospective and retrospective ones. The prevalence of NAFLD in IBD has increased in studies published from 2015 onwards: 23.2% (21.5-24.9) vs. 17.8% (13.2-22.9). Diagnostic methods for NAFLD determined prevalence figures, being highest in patients assessed by controlled attenuation parameter (38.8%; 33.1-44.7) compared to ultrasonography (28.5%; 23.1-34.2) or other methods. The overall prevalence of fibrosis was 16.7% (12.2-21.7) but varied greatly according to the measurement method.

CONCLUSION

One-quarter of patients with IBD might present with NAFLD worldwide. This proportion was higher in recent studies and in those that used current diagnostic methods.

The impact of nonalcoholic fatty liver disease on inflammatory bowel disease-related hospitalization outcomes: a systematic review

Evidence suggests that patients with inflammatory bowel disease are at higher risk of developing nonalcoholic fatty liver disease (NAFLD). However, there is limited information currently available on how NAFLD may affect the clinical course of IBD. Thus, we conducted a systematic review to evaluate the impact of NAFLD on IBD-related hospitalization outcomes. All observational studies assessing IBD-related hospitalization outcomes in patients with NAFLD were included. Exclusion criteria were studies published in languages other than English or French, or those involving pediatric population. Outcomes included IBD-related hospitalization and readmission rates, need for surgery, length of stay, inpatient mortality, and costs. Overall, 3252 citations were retrieved and seven studies met the inclusion criteria (1 574 937 patients); all were observational, of high quality, and originated in the United States. Measurable outcomes reported in these studies were few and with insufficient similarity across studies to complete a quantitative assessment. Only one study reports NAFLD severity. Two studies suggested a higher rate of hospitalization for patients with both NAFLD and IBD compared to IBD alone (incidence rate ratio of 1.54; 95% confidence interval: 1.33-1.79). This is the first systematic review to date that evaluates any possible association of NAFLD with IBD-related hospitalization outcomes. Despite the paucity and low quality of available data, our findings indicate that NAFLD may be associated with worse outcomes amongst IBD patients (especially Crohn's disease). Further and higher certainty of evidence is needed for better characterization of such clinical impact.

Influence of genetically predicted autoimmune diseases on NAFLD

Introduction

Non-alcoholic fatty liver disease (NAFLD), the emerging cause of end-stage liver disease, is the most common liver disease. Determining the independent risk factors of NAFLD and patients who need more monitoring is important.

Methods

Two-Sample Mendelian randomization (MR) was performed in the analysis to investigate the causal association of different autoimmune diseases with NAFLD using summary level data. Genome-wide association study (GWAS) of 5 autoimmune diseases including celiac disease (CeD), Crohn's disease (CD), multiple sclerosis (MS), rheumatoid arthritis (RA), and type 1 diabetes (T1D) were selected for Instrument variables (IVs). NAFLD was included as outcome.

Result

After adjusting for confounding factors, genetic predisposition of CeD (OR= 0.973, [0.949,0.997], IVW p-value=0.026), MS (OR= 1.048, [1.012,1.085], IVW p-value= 0.008), RA (OR= 1.036, [1.006,1.066], IVW p-value=0.019), T1D (OR= 1.039, [1.002,1.079], IVW p-value= 0.041) is causally associated with NAFLD. No causal effect was found between CD and NAFLD.

Conclusion

CeD itself may be a protective factor for NAFLD, the results of previous observational studies have been influenced by confounding factors, and the morbidity of NAFLD may be higher in patients with MS, RA, and T1D than in common populations, and monitoring the prevalence of NAFLD in these populations is considerable.

Use of IBD Drugs in Patients With Hepatobiliary Comorbidities: Tips and Tricks

Advanced therapies (biologic agents and small molecules) for inflammatory bowel diseases (IBD) have radically changed the management of these diseases during the last decade. Data about these drugs in patients with hepatic disorders derive mainly from real-life studies, as these conditions often represent an exclusion criterion from pivotal drug developmental trials. However, IBD patients sometimes have concomitant liver diseases. Nonalcoholic fatty liver disease is the most prevalent hepatic comorbidity, whereas viral hepatitis, primary sclerosing cholangitis, primary biliary cholangitis, autoimmune hepatitis, and hepatic vascular disorders are less frequent. This review aimed at describing the real-life data about the use of advanced therapies for IBD in patients with concomitant hepatobiliary disorders. Hepatitis B virus and hepatitis C virus infections do not represent an absolute contraindication for novel IBD therapeutic agents. Data from the literature suggest a safe hepatobiliary profile of biologic agents and small molecules in the case of nonalcoholic fatty liver disease, autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cholangitis, and portal vein thrombosis. Consequently, although the liver disease does not affect a different therapeutic approach in patients with concomitant IBD and liver disease, a close risk/benefit analysis for each drug should be performed in these patients, especially in cirrhotic patients and in the postliver transplant setting.

The Role of Tumor Necrosis Factor-Alpha in the Pathogenesis and Treatment of Nonalcoholic Fatty Liver Disease

PURPOSE OF REVIEW

To summarize experimental and clinical evidence on the association between tumor necrosis factor-α (TNF-α) and nonalcoholic fatty liver disease (NAFLD) and discuss potential treatment considerations.

RECENT FINDINGS

Experimental evidence suggests that TNF-α is a cytokine with a critical role in the pathogenesis of NAFLD. Although, the production of TNF-α may be an early event during the course of nonalcoholic fatty liver (NAFL), TNF-α may play a more substantial role in the pathogenesis of nonalcoholic steatohepatitis (NASH) and NAFLD-associated fibrosis. Moreover, TNF-α may potentiate hepatic insulin resistance, thus interconnecting inflammatory with metabolic signals and possibly contributing to the development of NAFLD-related comorbidities, including cardiovascular disease, hepatocellular carcinoma, and extra-hepatic malignancies. In clinical terms, TNF-α is probably associated with the severity of NAFLD; circulating TNF-α gradually increases from controls to patients with NAFL, and then, to patients with NASH. Given this potential association, various therapeutic interventions (obeticholic acid, peroxisome proliferator-activated receptors, sodium-glucose co-transporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, probiotics, synbiotics, rifaximin, vitamin E, pentoxifylline, ursodeoxycholic acid, fibroblast growth factor-21, n-3 polyunsaturated fatty acids, statins, angiotensin receptor blockers) have been evaluated for their effect on TNF-α and NAFLD. Interestingly, anti-TNF biologics have shown favorable metabolic and hepatic effects, which may open a possible therapeutic window for the management of advanced NAFLD. The potential key pathogenic role of TNF-α in NAFLD warrants further investigation and may have important diagnostic and therapeutic implications.

Steroid Use and Risk of Nonalcoholic Fatty Liver Disease in Patients With Inflammatory Bowel Disease: Systematic Review and Meta-analysis

GOALS

We sought to evaluate the association of steroids with nonalcoholic fatty liver disease (NAFLD) among patients with inflammatory bowel disease (IBD).

BACKGROUND

Patients with IBD are at increased risk of NAFLD. Steroids may have a role in the pathogenesis of NAFLD.

STUDY

We searched MEDLINE (through PubMed) and Embase for studies from inception to July 2021. We included published interventional and observational studies of adults 18 years or older with ulcerative colitis or Crohn's disease. We reported odds ratios, 95% confidence intervals, and generated forest plots. A random effects model generated a summary effect estimate. Publication bias was assessed by funnel plot and Egger's test. Study quality was examined using modified Newcastle-Ottawa scale (NOS) and Agency for Healthcare Research and Quality (AHRQ).

RESULTS

A total of 12 observational studies with 3497 participants were included. NAFLD was identified in 1017 (29.1%) patients. The pooled odds ratio for the development of NAFLD in steroid users versus non-users was 0.87 (95% confidence interval: 0.72-1.04). There was no significant heterogeneity between studies ( I ²=0.00%, P =0.13). No publication bias was detected by funnel plot or Egger's test ( P =0.24). Findings were consistent among subgroup analyses stratified by study quality.

CONCLUSION

In this meta-analysis, steroids were not associated with NAFLD in patients with IBD. Steroids may not need to be withheld from patients with IBD for the purposes of preventing NAFLD. Additional prospective studies that systematically document steroid exposure and important confounders among patients with IBD are warranted.

Liver Fibrosis in Non-Alcoholic Fatty Liver Disease and Progression to Hepatocellular Carcinoma in Patients with Inflammatory Bowel Disease: A Systematic Review

The aim of the systematic review is to assess the prevalence and risk factors of liver fibrosis in patients with Inflammatory Bowel Disease (IBD) and Non-Alcoholic Fatty Liver Disease (NAFLD) and to discuss the role of liver fibrosis in the progression to hepatocellular carcinoma (HCC). We performed a structured search in PubMed, Web of Science, Embase, and Scopus up to 3 March 2023 to identify observational studies reporting liver fibrosis in patients with NAFLD and IBD. Quality of studies was assessed using the Newcastle-Ottawa Scale (NOS) score. A total of 23 studies met our inclusion criteria, including 629,781 patients. A total of 10 cross-sectional, 3 case-control, and 10 cohort studies were included. Fourteen studies had a NOS score ≥ 7 points. NAFLD was diagnosed in 2162/6332 (34.1%) IBD participants. However, NAFLD diagnosis was established in 924/2962 (31.2%) healthy individuals without IBD. Advanced liver fibrosis was found in 116 (11.6%) of 992 IBD patients with NAFLD. Most studies found an association between NAFLD and classic cardiovascular risk factors such as older age, male sex, higher BMI, diabetes, hypertension and dyslipidemia. In addition, metabolic syndrome features were also associated with an increased risk of significant and advanced liver fibrosis. Although no strong association between NAFLD and IBD therapy was reported, some studies associated NAFLD with IBD diagnosis, Crohn's Disease, a complicated course of IBD, disease activity, and IBD duration. Advanced liver fibrosis was also associated with Crohn's disease in several studies. In conclusion, NAFLD and advanced liver fibrosis are prevalent and clinically relevant extraintestinal manifestations, so its diagnosis and potential progression to HCC should be carefully considered in daily clinical practice.

Increased Risk of Non-Alcoholic Steatohepatitis in Patients With Inflammatory Bowel Disease: A Population-Based Study

Background and objective The global health burden of inflammatory bowel disease (IBD) stems from its increasing incidence over the years. Comprehensive studies on the topic hypothesize that IBD plays a more dominant in the development of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). In light of this, we conducted this study with the aim of assessing the prevalence and risk factors of developing NASH in patients who have had a diagnosis of ulcerative colitis (UC) and Crohn's disease (CD). Methodology A validated multicenter and research platform database of more than 360 hospitals from 26 different healthcare systems across the United States from 1999 to September 2022 was utilized for conducting this study. Patients aged 18-65 years were included. Pregnant patients and individuals diagnosed with alcohol use disorder were excluded. The risk of developing NASH was calculated using a multivariate regression analysis to account for potential confounding variables including male gender, hyperlipidemia, hypertension, type 2 diabetes mellitus (T2DM), and obesity. A two-sided p-value <0.05 was considered statistically significant, and all statistical analyses were performed using R version 4.0.2 (R Foundation for Statistical Computing, Vienna, Austria, 2008). Results A total of 79,346,259 individuals were screened in the database and 46,667,720 were selected for the final analysis based on the inclusion and exclusion criteria. Using multivariate regression analysis, the risk of developing NASH among patients with UC and CD was calculated. The odds of having NASH among patients with UC was 2.37 (95% CI: 2.17-2.60, p<0.001). Similarly, the odds of having NASH were high in patients with CD as well, at 2.79 (95% CI: 2.58-3.02, p<0.001). Conclusion Based on our findings, patients with IBD have an increased prevalence and higher odds of developing NASH after controlling for common risk factors. We believe that a complex pathophysiological relationship exists between both disease processes. Further research is required to establish appropriate screening times to enable earlier disease identification and thereby improve patient outcomes.

Crohn's Disease Is Associated with Liver Fibrosis in Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

Chronic inflammation in IBD is postulated to drive NAFLD progression from steatosis to fibrosis.

AIMS

To study the histopathological spectrum of NAFLD in Crohn disease (CD) and Ulcerative colitis (UC).

METHODS

Patients with biopsy proven NAFLD at a quaternary center from 2008 to 2018 were included in this retrospective analysis. Inflammatory bowel disease (IBD) diagnosed either clinically and/or endoscopically at the time of liver biopsy. Multivariable regression and propensity score (PS) weighted analysis were conducted. Statistical analysis were performed using SAS statistical software.

RESULTS

Among 1009 patients with NAFLD a diagnosis of IBD was identified in 50 cases (34 CD and 16 UC). On multivariable analysis; CD was independently associated with significantly higher odds of advanced fibrosis (AF) on liver biopsy (adjusted OR = 4.09, 95% CI = 1.40-11.94) compared to NAFLD patients without IBD. Similar results were obtained with both the overlap PS weighted model (OR = 3.17, 95% CI = 1.55-6.49) and the PS matched model (OR = 3.49, 95% CI = 1.50-8.13).

CONCLUSION

In a large cohort of patients with histologically well characterized NAFLD, AF was more common in CD patients than NAFLD patients without IBD. These findings must be confirmed in a larger cohort, but suggest CD patients with NAFLD could be at greater risk for liver fibrosis.

Tetrastigma hemsleyanum leaf extracts ameliorate NAFLD in mice with low-grade colitis via the gut-liver axis

Nonalcoholic fatty liver disease (NAFLD) is a complex metabolic disorder, manifested as oxidative stress, lipid accumulation, and inflammation of the liver. Tetrastigma hemsleyanum leaves (THL), which are rich in flavonoids and phenolic acids, have good anti-inflammatory, antioxidant, and hepatoprotective effects. However, it is unknown whether THL extracts can improve NAFLD and the underlying mechanisms are unknown. Hence, this study was designed to investigate the effects of THL extracts on NAFLD and perform a preliminary inquiry into the underlying mechanism based on the gut-liver axis. The results showed that THL extracts could reverse NAFLD-related oxidative stress, lipid accumulation, and inflammation. Additionally, the protective effect of THL extracts on the gut includes the maintenance of the intestinal barrier and the regulation of gut microbiota, which may be one of the mechanisms by which THL improves NAFLD. To be specific, in our study, THL extracts alleviated hepatic lipid accumulation and oxidative stress by regulating the expression of lipid synthesis/catabolism and the oxidative stress genes (SREBP-1c/ACC-1/PPAR-α/PPAR-γ/Keap1/Nrf2). In addition, THL extracts reduced damage to the intestinal barrier (ZO-1/Mucin2/occludin) and increased the relative abundance of Lactobacillales, Ruminococcaceae, and Bifidobacteriales in NAFLD mice. In short, THL extracts alleviated NAFLD-related oxidative stress, lipid accumulation, and inflammation in NAFLD mice which may be via the gut-liver axis (gut barrier integrity and gut microbiota).

Liver biopsy in inflammatory bowel disease patients with sustained abnormal liver function tests: a retrospective single-center study

Background

Inflammatory bowel disease (IBD) may be associated with a wide range of hepatobiliary manifestations. This study aimed to characterize the spectrum of hepatobiliary disorders in patients with IBD who underwent liver biopsy for sustained abnormal liver function tests (LFT).

Method

A retrospective study was performed of all patients with IBD who underwent liver biopsy between January 2010 and December 2020 for sustained abnormal LFT (at least 6-month duration).

Results

A total of 101 patients were included, mostly male (62.4%), with a mean age of 44.4±13.3 years. The most common IBD type was Crohn's disease (61.4%). Median time interval between abnormal LFT and biopsy was 14 (7-36) months. Abnormal LFT was predominantly hepatocellular in 40 patients (39.6%), cholestatic in 26 (25.7%) and mixed in 35 (34.7%). The most frequent diseases were nonalcoholic fatty liver disease (NAFLD) in 33 patients (32.7%), drug-induced liver disease (DILI) in 30 (29.7%), autoimmune hepatitis (AIH) in 13 (12.9%) and primary sclerosing cholangitis (PSC) in 13 (12.9%). Three patients had primary biliary cholangitis. Remarkably, 70 patients (69.3%) already had fibrosis by the time of liver biopsy and in 6 (5.9%) liver disease was already detected in the stage of cirrhosis.

Conclusions

Abnormal LFT in IBD patients had a wide range of etiologies and histology was often essential for reaching a correct diagnosis. NAFLD, DILI, AIH and PSC were the most common diagnoses and patients often presented in cirrhotic stage. Therefore, liver biopsy must be considered early in IBD patients with unexplained sustained abnormal LFT.

MAFLD: a multisystem disease

Nonalcoholic fatty liver disease (NAFLD), affecting about 25% of general population and more than 50% of dysmetabolic patients, is an emerging cause of chronic liver disease and its complications. Recently, an international consensus of experts proposed to rename this disease as 'Metabolic dysfunction-Associated Fatty Liver Disease' (MAFLD) to focus on the bidirectional interplay between fatty liver and metabolic alterations and to stress the need of assessing fatty liver independently from alcohol consumption and other coexisting causes of liver disease. The peculiarity of NAFLD/MAFLD lies in the presence of a higher risk of not only - as expected - liver-related events but also of extrahepatic events, mostly cardiovascular and cancers. Available evidence suggests that these associations are not only the expression of sharing the same risk factors but shed light about the ability of NAFLD/MAFLD and particularly of its progressive form - nonalcoholic/metabolic dysfunction-associated steatohepatitis - to act as an independent risk factor via promotion of atherogenic dyslipidemia and a proinflammatory, profibrogenic, and procoagulant systemic environment. The present review summarizes available epidemiological and clinical evidence supporting the concept of NAFLD/MAFLD as a multisystemic disease, and highlights potential explanatory mechanisms underlying the association between NAFLD/MAFLD and extrahepatic disorders.

Gut Microbiota in Non-Alcoholic Fatty Liver Disease Patients with Inflammatory Bowel Diseases: A Complex Interplay

The intestinal microbiota represents the microbial community that colonizes the gastrointestinal tract and constitutes the most complex ecosystem present in nature. The main intestinal microbial phyla are Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Fusobacteria, and Verrucromicrobia, with a clear predominance of the two phyla Firmicutes and Bacteroidetes which account for about 90% of the intestinal phyla. Intestinal microbiota alteration, or dysbiosis, has been proven to be involved in the development of various syndromes, such as non-alcoholic fatty liver disease, Crohn's disease, and ulcerative colitis. The present review underlines the most recurrent changes in the intestinal microbiota of patients with NAFLD, Crohn's disease, and ulcerative colitis.

Inflammatory bowel disease type influences development of elevated liver enzymes

Background and Aim

Up to a third of patients with inflammatory bowel disease (IBD) have elevated liver enzymes (ELE). We evaluated the incidence, predictors, and outcomes associated with ELE in a diverse and vulnerable IBD cohort.

Methods

We retrospectively evaluated 336 IBD patients receiving care at the San Francisco safety net gastroenterology clinics between June 1996 and December 2019. Baseline characteristics were captured at first visit, then patients were followed until last clinic activity or death. Testing and etiology, pattern of ELE defined as transient (<1 month) or persistent (≥1 month), were assessed. Multivariate modeling evaluated predictors of ELE at baseline, new ELE at follow-up, and pattern of ELE.

Results

Baseline median age was 40.3 years, 62% male, 46% White (13% Black, 19% Asian, and 18% Latino), and 59% had ulcerative colitis (UC). Among those without known liver disease (n = 14), 51.6% (166 of 322; 52 at baseline, 114 during follow-up) had ELE. In multivariate logistic regression, 5-aminosalicylic acid use (odds ratio [OR] 2.2, 95% confidence interval [CI]: 1.07-4.4, P = 0.03) and higher body mass index (OR 1.08, 95% CI: 1.02-1.14, P = 0.01) were associated with baseline ELE. In multivariate Cox regression, UC (vs. Crohn's disease [CD]) had a 34% lower risk of developing new ELE during follow-up (hazard ratio [HR] 0.66, 95% CI: 0.46-0.95, P = 0.02). Mortality rate was higher for patients with ELE (0% normal vs 2.3% transient ELE vs 6.5% persistent ELE, P < 0.001).

Conclusion

ELE is prevalent in IBD, especially in CD, and associated with higher rates of mortality. Identification and management of ELE particularly when persistent are important to IBD outcomes.

Screening for Liver Steatosis and Fibrosis in Patients with Inflammatory Bowel Disease Using Vibration Controlled Transient Elastography with Controlled Attenuation Parameter

BACKGROUND AND AIMS

Inflammatory bowel diseases (IBD) are frequently associated with extraintestinal manifestations, hepatic injury being of concern in these patients. Current literature reports an increased prevalence of liver steatosis and fibrosis in subjects with IBD and the pathophysiology is yet to be completely understood. The aim of this study was to assess the prevalence of non-alcoholic fatty liver disease (NAFLD) in patients with IBD, as well as to determine the factors that connect these two disorders.

METHODS

From September 2021 to June 2022, 82 consecutive IBD patients were enrolled from a tertiary care center hospital in Iasi. Vibration-Controlled Transient Elastography with Controlled Attenuation Parameter (CAP) was used to assess the presence of NAFLD, with a cut-off score for CAP of 248 dB/m. Significant liver fibrosis was considered at a cut-off for liver stiffness measurements (LSM) of 7.2 kPa.

RESULTS

In total, 82 IBD patients (54.8% men, mean age of 49 ± 13 years) were included, 38 (46.3%) of them being diagnosed with NAFLD, with a mean CAP score of 286 ± 35.4 vs. 203 ± 29.7 in patients with IBD only. Age (β = 0.357, p = 0.021), body mass index (BMI) (β = 0.185, p = 0.048), disease duration (β = 0.297, p = 0.041), C-reactive protein (β = 0.321, p = 0.013), fasting plasma glucose (β = 0.269, p = 0.038), and triglycerides (β = 0.273, p = 0.023) were strongly associated with the presence of liver steatosis. The multivariate analysis showed that older age, BMI, and disease duration were strongly associated with significant liver fibrosis in our group.

CONCLUSIONS

NAFLD is a multifaced pathology with growing prevalence among IBD patients. Additional studies are needed to completely understand this problem and to create a solid evidence-based framework for more effective preventative and intervention strategies.

Risk of Cancer in Inflammatory Bowel Diseases: Umbrella Review and Reanalysis of Meta-analyses

BACKGROUND & AIMS

To summarize the epidemiologic evidence and assess the validity of claimed associations of inflammatory bowel diseases (IBDs) with overall and site-specific cancer risk.

METHODS

We systematically searched PubMed, Embase, and Scopus from inception to May 10, 2021, to identify and comprehensively reanalyze the data of meta-analyses on associations between IBDs (ie, Crohn's disease [CD] and ulcerative colitis [UC]) and subsequent risk of cancer. The strength of epidemiologic evidence was graded as high, moderate, or weak, by applying prespecified criteria that included the random effects estimate, its 95% confidence interval, and P value, estimates of heterogeneity, small-study effects, and robustness to unmeasured confounding.

RESULTS

This study critically appraised 277 estimates derived from 24 published meta-analyses and our own meta-analyses. The association between pediatric-onset IBDs and overall risk of cancer showed high epidemiologic evidence. Twenty associations (15 cancer types) demonstrated moderate evidence: any cancer (pediatric-onset UC), mouth to terminal ileum (CD), small bowel (CD/UC), colon (CD), rectum (CD/UC), colon-rectum (IBDs, pediatric-onset CD/UC), bile ducts and liver (CD/UC), liver (CD), intrahepatic cholangiocarcinoma (IBDs), bile ducts (CD), skin (CD), squamous cell carcinoma of the skin (CD), nonmelanoma skin cancer (UC), kidney (CD), and thyroid cancer (IBDs). Another 40 associations (23 cancer types) showed statistical significance; however, our confidence in these effect estimates was weak. No statistical significance was found regarding further 47 associations.

CONCLUSIONS

Associations between IBDs and different types of malignancy showed varying levels of evidence and magnitude of risk. Further primary research investigating the impact of a consistent set of risk factors that are known to affect cancer risk is warranted.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021254996.

Inflammatory Bowel Disease-associated Fatty Liver Disease: the Potential Effect of Biologic Agents

Inflammatory bowel diseases [IBD] exhibit intestinal and systemic manifestations. Nonalcoholic fatty liver disease [NAFLD] is a common co-existing condition, possibly contributing to the cardio-metabolic burden and overall morbidity. Εmerging therapeutic choices of biologic agents have modified the clinical course of IBD; however, their impact on IBD-associated NAFLD has not been extensively evaluated. The prevalence of NAFLD varies among IBD patients, but it appears higher than in the general population in the majority of quality studies. In terms of pathogenetic and risk factors of NAFLD, they may vary with IBD activity. Dysbiosis, mucosal damage, and cytokine release have been implicated in the pathogenesis during the relapses, whereas metabolic risk factors seem to play a dominant role during the remissions of IBD. Considering biologics, although quality data are scarce, agents suppressing tumour necrosis factor may offer potential benefits in IBD-associated NAFLD, whereas anti-integrins do not appear to confer any therapeutic advantage. In conclusion, IBD-associated NAFLD possibly follows two different patterns, one manifested during the relapses and one during the remissions of IBD. Some, but not all, biologics may benefit NAFLD in patients with IBD. Further mechanistic and prospective cohort studies are warranted to illuminate the effects of various biologics on NAFLD.

The Impact of NAFLD on Hospitalization Outcomes in Patients With Inflammatory Bowel Diseases: Nationwide Analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in patients with inflammatory bowel diseases (IBD). Yet, the impact of NAFLD on outcomes, along with the contribution of nonmetabolic factors to NAFLD development, is unclear. To investigate these topics, we conducted a nationwide study examining the impact of NAFLD on hospitalization outcomes in IBD patients after adjusting for metabolic factors.

METHODS

Patients with IBD-related hospitalizations were identified using the Nationwide Readmissions Database from 2016 to 2018. Inflammatory bowel disease patients with and without NAFLD were matched based on IBD type, age, sex, metabolic syndrome, and diabetes mellitus. Primary outcomes were IBD-related readmission, IBD-related surgery, and death. Secondary outcomes were length of stay (LOS) and cost of care (COC). The primary multivariable model adjusted for obesity, dyslipidemia, Charlson-Deyo comorbidity index, hospital characteristics, payer, patient income, and elective status of admissions.

RESULTS

Nonalcoholic fatty liver disease was associated with a higher risk of IBD-related readmission (adjusted hazard ratio, 1.90; P < .01) and death (adjusted hazard ratio, 2.73; P < .01), 0.71-day longer LOS (P < .01), and $7312 higher COC (P < .01) in those with Crohn's disease. Nonalcoholic fatty liver disease was also associated with a higher risk of IBD-related readmission (adjusted hazard ratio, 1.65; P < .01), 0.64-day longer LOS (P < .01), and $9392 (P < .01) higher COC, but there was no difference in death in those with UC. No differences in risk of IBD-related surgery were observed.

CONCLUSIONS

Nonalcoholic fatty liver disease is associated with worse hospitalization outcomes in IBD patients after adjusting for metabolic factors. These data suggest nonmetabolic factors may be implicated in the pathogenesis of NAFLD in IBD patients and may contribute to worsened clinical outcomes.

Mendelian Randomization Rules Out Causation Between Inflammatory Bowel Disease and Non-Alcoholic Fatty Liver Disease

Background: Inflammatory bowel disease (IBD) and non-alcoholic fatty liver disease (NAFLD) usually co-exist clinically. However, whether such association is causal is still unknown.

Methods: Genetic variants were extracted as instrumental variables from the largest genome-wide association study (GWAS) of IBD, Crohn’s disease (CD) and ulcerative colitis (UC) with 25,042 cases and 34,915 controls (GWAS p-value < 5 × 10⁻⁸). Information of genetic variants in NAFLD was extracted from a GWAS with 1,483 cases and 17,781controls. Also, liver fat content (LFC) was included as the outcome. Then, a bi-direction Mendelian randomization (MR) was carried out to appraise the causal relationship between NAFLD on IBD. Besides, a multivariable MR (MVMR) design was carried to adjust for body mass index (BMI) and type 2 diabetes (T2D) as well.

Results: Generally, IBD might not affect the risk of NAFLD (OR = 0.994 [0.970, 1.019]), together with its subtypes including UC and CD. However, genetically-elevated risk of IBD might cause liver fat accumulation (beta = 0.019, p-value = 0.016) while turning insignificant at Bonferroni correction. Besides, no causal effect of NAFLD on IBD was observed (OR = 0.968 [0.928, 1.009]), together with UC and CD. Also, genetically-elevated LFC could not impact IBD, UC and CD either. The MR CAUSE analysis supported these null associations and MVMR analysis also supported such null associations even after adjusting for BMI and T2D.

Conclusion: This MR study ruled out the causal relationship between IBD and NAFLD, suggesting therapeutics targeting NAFLD might not work for IBD and vice versa.

Hepatic Steatosis and Fibrosis in Chronic Inflammatory Bowel Disease

Background and Purpose: Chronic inflammatory bowel diseases (IBD) frequently affect extraintestinal organs including the liver. Since limited evidence suggests the presence of liver disease in IBD patients, we studied the frequency of hepatic steatosis and fibrosis in these patients and characterized disease-related factors. Methods: In this retrospective, cross-sectional, hospital-based, single-center study, consecutive patients with Crohn’s disease (CD) and ulcerative colitis (UC) were included who had undergone routine abdominal ultrasound including transhepatic elastography. Hepatic steatosis was diagnosed by hyperechogenicity on B-mode ultrasound and by measuring controlled attenuation parameter (CAP). Hepatic fibrosis was assumed if transhepatic elastography yielded a stiffness > 7 kPa. Results: 132 patients (60% CD) with a median disease duration of 10 years were included. Steatosis assessed by B-mode ultrasound and CAP correlated well. Of the IBD patients, 30.3% had non-alcoholic fatty liver (NAFL). Factors associated with NAFL were age, BMI, duration of disease, as well as serum activities of aspartate-aminotransferase (AST) and gamma-glutamyl-transpeptidase (GGT). In multivariate analysis, only disease duration was independently associated with hepatic steatosis. Hepatic fibrosis was found in 10 (8%) of all IBD patients, predominantly in patients with CD (10/11). Conclusions: Pure hepatic steatosis is common in both CD and UC, whereas hepatic fibrosis occurs predominantly in CD patients. Association of disease duration with NAFLD suggests a contribution of IBD-related pathogenetic factors. Longitudinal studies are needed to better understand the impact of IBD on hepatic disorders.

Meta-analysis: prevalence of, and risk factors for, non-alcoholic fatty liver disease in patients with inflammatory bowel disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is found in inflammatory bowel disease (IBD). However, uncertainties remain on the magnitude of the association.

AIMS

To explore systematically the prevalence of, and risk factors for, NAFLD in IBD patients.

METHODS

We searched medical literature using Embase, PubMed, Web of Science, Scopus and ProQuest, from inception to September 30, 2021. We included observational studies reporting the prevalence of NAFLD in ≥50 adult patients with IBD. Diagnosis of NAFLD could be based on imaging, histopathology, and/or hepatic steatosis index. Sex, age, body mass index (BMI), diabetes, hypertension, dyslipidemia, prior surgery (bowel resection), corticosteroids, biologics and immunomodulators were assessed as potential risk factors for NAFLD.

RESULTS

Of 1893 citations, 44 eligible studies were finally included, comprising 14 947 subjects from 18 different countries. Pooled prevalence of NAFLD was 30.7% (95% confidence interval [CI] 26.5-34.9) in patients with IBD worldwide, which varied regionally. No significant difference was observed in the odds ratio (OR) of NAFLD among Crohn's disease (CD) patients compared with ulcerative colitis (UC) patients (1.16, 95% CI 0.93-1.44). Risk of NAFLD was almost twice as high in patients with IBD as in healthy subjects (OR 1.96, 95% CI 1.13-3.41). Age (adjusted OR 1.03, 95% CI 1.01-1.05) and BMI (adjusted OR 1.27, 95% CI 1.22-1.32) were statistically significantly associated with increased risk of NAFLD. The pooled prevalence of advanced liver fibrosis in IBD patients with NAFLD was 13.6% (95% CI 7.6-19.7) based on six studies.

CONCLUSION

Up to one-third of patients with IBD experienced NAFLD worldwide. The risk of NAFLD was two times higher in IBD patients versus healthy subjects.

Disease activity in inflammatory bowel disease patients is associated with increased liver fat content and liver fibrosis during follow-up

PURPOSE

Liver steatosis is a frequently reported condition in patients with inflammatory bowel disease (IBD). Different factors, both metabolic and IBD-associated, are believed to contribute to the pathogenesis. The aim of our study was to calculate the prevalence of liver steatosis and fibrosis in IBD patients and to evaluate which factors influence changes in steatosis and fibrosis during follow-up.

METHODS

From June 2017 to February 2018, demographic and biochemical data was collected at baseline and after 6-12 months. Measured by transient elastography (FibroScan), liver steatosis was defined as Controlled Attenuation Parameter (CAP) ≥248 and fibrosis as liver stiffness value (Emed) ≥7.3 kPa. IBD disease activity was defined as C-reactive protein (CRP) ≥10 mg/l and/or fecal calprotectin (FCP) ≥150 μg/g. Univariate and multivariate regression analysis was performed; a p-value of ≤0.05 was considered significant.

RESULTS

Eighty-two out of 112 patients were seen for follow-up; 56% were male. The mean age was 43 ± 16.0 years, and mean BMI was 25.1 ± 4.7 kg/m². The prevalence of liver steatosis was 40% and of fibrosis was 20%. At baseline, 26 patients (32%) had an active episode of IBD. Using a multivariate analysis, disease activity at baseline was associated with an increase in liver steatosis (B = 37, 95% CI 4.31-69.35, p = 0.027) and liver fibrosis (B = 1.2, 95% CI 0.27-2.14, p = 0.016) during follow-up.

CONCLUSIONS

This study confirms the relatively high prevalence of liver steatosis and fibrosis in IBD patients. We demonstrate that active IBD at baseline is associated with both an increase in liver steatosis and fibrosis during follow-up.

Analysis of Common Pathways and Markers From Non-Alcoholic Fatty Liver Disease to Immune-Mediated Diseases

Metabolic associated fatty liver disease (MAFLD) is the most prevalent form of liver disease worldwide, accounting for a high liver-related mortality and morbidity with extensive multi-organ involvement. This entity has displaced viral hepatitis as the main cause of severe forms of hepatic diseases, although the onset and transition of MAFLD stages still remains unclear. Nevertheless, innate and adaptive immune responses seem to play an essential role in the establishment and further progression of this disease. The immune system is responsible of safeguard and preserves organs and systems function, and might be altered under different stimuli. Thus, the liver suffers from metabolic and immune changes leading to different injuries and loss of function. It has been stablished that cell-cell crosstalk is a key process in the hepatic homeostasis maintenance. There is mounting evidence suggesting that MAFLD pathogenesis is determined by a complex interaction of environmental, genetic and host factors that leads to a full plethora of outcomes. Therefore, herein we will revisit and discuss the interplay between immune mechanisms and MAFLD, highlighting the potential role of immunological markers in an attempt to clarify its relationship.

Hepatobiliary phenotype of individuals with chronic intestinal disorders

Despite the known functional relationship between the gut and the liver, the clinical consequences of this circuit remain unclear. We assessed the hepatobiliary phenotype of cohorts with celiac disease (CeD), Crohn´s disease (CD) and ulcerative colitis (UC). Baseline liver function tests and the frequency of hepatobiliary diseases were analyzed in 2377 CeD, 1738 CD, 3684 UC subjects and 488,941 controls from the population-based UK Biobank cohort. In this cohort study associations were adjusted for age, sex, BMI, diabetes, and alcohol consumption. Compared to controls, cohorts with CeD, but not CD/UC displayed higher AST/ALT values. Subjects with CD/UC but not CeD had increased GGT levels. Elevated ALP and cholelithiasis were significantly more common in all intestinal disorders. Non-alcoholic steatohepatitis and hepatocellular carcinoma (HCC) were enriched in CeD and CD (NASH: taOR = 4.9 [2.2-11.0] in CeD, aOR = 4.2 [1.7-10.3] in CD, HCC: aOR = 4.8 [1.8-13.0] in CeD, aOR = 5.9 [2.2-16.1] in CD), while cholangitis was more common in the CD/UC cohorts (aOR = 11.7 [9.1-15.0] in UC, aOR = 3.5 [1.8-6.8] in CD). Chronic hepatitis, autoimmune hepatitis (AIH) and cirrhosis were more prevalent in all intestinal disorders. In UC/CD, a history of intestinal surgery was associated with elevated liver enzymes and increased occurrence of gallstones (UC: aOR = 2.9 [2.1-4.1], CD: 1.7 [1.2-2.3]). Our data demonstrate that different intestinal disorders predispose to distinct hepatobiliary phenotypes. An increased occurrence of liver cirrhosis, NASH, AIH and HCC and the impact of surgery warrant further exploration.

The Other Side of Malnutrition in Inflammatory Bowel Disease (IBD): Non-Alcoholic Fatty Liver Disease

Steatohepatitis and hepatobiliary manifestations constitute some of the most common extra-intestinal manifestations of Inflammatory Bowel Disease (IBD). On the other hand, non-alcoholic fatty liver disease (NAFLD) affects around 25% of the world’s population and is attracting ever more attention in liver transplant programs. To outline the specific pathways linking these two conditions is a pressing task for 21st-century researchers. We are accustomed to expecting the occurrence of fatty liver disease in obese people, but current evidence suggests that there are several different pathways also occurring in underweight patients. Genetic factors, inflammatory signals and microbiota are key players that could help in understanding the entire pathogenesis of NAFLD, with the aim of defining the multiple expressions of malnutrition. In the current review, we summarize the most recent literature regarding the epidemiology, pathogenesis and future directions for the management of NAFLD in patients affected by IBD.

Insulin Resistance Is Not Increased in Inflammatory Bowel Disease Patients but Is Related to Non-Alcoholic Fatty Liver Disease

BACKGROUND

Insulin resistance (IR) has been linked to inflammatory states. The aim of this study was to determine whether IR is increased in a cohort of inflammatory bowel disease (IBD) patients with low disease activity. We additionally intended to establish which factors were the determinants of IR in this population, including the presence of nonalcoholic fatty liver disease (NAFLD).

METHODS

Cross-sectional study encompassing 151 IBD patients and 174 non-diabetic controls. Insulin and C-peptide serum levels and IR and beta cell function (%B) indices based on homoeostatic model assessment (HOMA2) were assessed in patients and controls. Liver stiffness as measured by transient elastography, and the presence of NAFLD detected via ultrasound were additionally assessed. A multivariable regression analysis was performed to evaluate the differences in IR indexes between patients and controls, and to determine which predictor factors were associated with IR in IBD patients.

RESULTS

Neither HOMA2-IR (beta coef. -0.26 {95%CI -0.64-0.13}, p = 0.19) nor HOMA2-%B (beta coef. 15 {95%CI -14-44}, p = 0.31) indexes differed between patients and controls after fully multivariable analysis. Among classic IR risk factors, obesity, abdominal circumference, and triglycerides significantly and positively correlated with IR indexes in IBD patients. However, most features related to IBD, such as disease patterns, disease activity, and inflammatory markers, were not associated with IR. The presence of NAFLD was independently and significantly associated with beta cell dysfunction in patients with IBD (HOMA2-B grade 4, 251 ± 40 vs. grade 1, 107 ± 37, p = <0.001).

CONCLUSIONS

IR is not increased in IBD patients with low disease activity compared to controls. However, the presence of NAFLD favors the development of IR in patients with IBD.

Evaluation of non-alcoholic fatty liver disease in patients with inflammatory bowel disease using controlled attenuation parameter technology: A Taiwanese retrospective cohort study

Background/purpose

An increased prevalence of non-alcoholic fatty liver disease (NAFLD) is observed in patients with inflammatory bowel disease (IBD) in Western countries. Both intestinal inflammation and metabolic factors contribute to the pathogenesis of IBD-associated NAFLD. The burden of NAFLD is not clear in the Asian population. This study aimed to evaluate the prevalence of NAFLD and liver fibrosis in a cohort of Taiwanese patients with IBD.

Methods

From January to December 2019, patients with IBD who underwent ultrasound examination were enrolled. Hepatic steatosis and fibrosis were measured with liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) using FibroScan. Patients with a history of excessive alcohol or recent steroid use were excluded. Univariate and multivariate analysis were performed.

Results

A total of 81 consecutive patients were enrolled and included in the analysis (45 with ulcerative colitis, 36 with Crohn’s disease). The median age was 42 years old. The patients were classified in terms of body mass index as normal weight (54.3%), underweight (11.1%), overweight (28.4%), and obese (6.2%). The mean CAP increased to 162.22 dB/m in the underweight group, 210.86 dB/m in the normal weight group, 260.7 dB/m in the overweight group, and 274.0 dB/m in the obese group. NAFLD was observed in 29.6% of the patients, 1.2% of which had significant fibrosis. Increased body mass index (odds ratio [OR] 1.33, 95% confidence interval [CI] 1.1–1.62) and older age at IBD diagnosis (OR: 1.05, 95% CI 1–1.11) was found to be associated with the presence of NAFLD.

Conclusion

In this study, the prevalence of NAFLD was lower (29.6%) in IBD patients than in the Western population. Higher BMI and older age were associated with NAFLD in our study.

Pediatric nonalcoholic fatty liver disease and the microbiome: Mechanisms contributing to pathogenesis and progression

Nonalcoholic fatty liver disease (NAFLD) is the most common form of pediatric liver disease in the United States, and often associated with obesity and metabolic syndrome. NAFLD comprises a broad spectrum of liver diseases, from hepatic steatosis to steatohepatitis, fibrosis and cirrhosis. Disease progression is considered a multi-modal process of liver injury. The intestinal microbiome has been implicated in several aspects of NAFLD pathophysiology. Pediatric studies associating the intestinal microbiome with NAFLD have been limited in number and complicated by inconsistencies in study design and approach. Nevertheless, they provide support for involvement of the intestinal microbiome in NAFLD development and progression and point to common mechanisms shared by microbiome-associated inflammatory diseases with potential to inform future therapeutic intervention.

Evaluation of Nonalcoholic Fatty Liver Disease in Pediatric Patients With Inflammatory Bowel Disease

Adult studies demonstrate the co-existence of nonalcoholic fatty liver disease (NAFLD) and inflammatory bowel disease (IBD) without traditional risk factors. Data in children with IBD are lacking. Here, we sought to establish the prevalence of NAFLD in a single-center pediatric IBD cohort, and identify potential risk factors. After institutional review board approval, we enrolled children with IBD who underwent routine abdominal magnetic resonance enterography. Proton density fat fraction (PDFF) was then estimated on magnetic resonance enterography. A total of 83 patients with IBD were identified and PDFF maps completed. Five (6%) were found to have PDFF >5%, meeting criteria for NAFLD. Compared to the patients with IBD without NAFLD, none of the evaluated risk factors including age, sex, diagnosis, time since diagnosis, medication, median alanine aminotransferase, and weight status were statistically significant. Our findings demonstrate the occult nature of NAFLD in pediatric IBD. The prevalence is not at variance with what is expected in general teenage populations.