Geo-epidemiology and environmental co-variate mapping of primary biliary cholangitis and primary sclerosing cholangitis

Role of microbiome in autoimmune liver diseases

The microbiome plays a crucial role in integrating environmental influences into host physiology, potentially linking it to autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. All autoimmune liver diseases are associated with reduced diversity of the gut microbiome and altered abundance of certain bacteria. However, the relationship between the microbiome and liver diseases is bidirectional and varies over the course of the disease. This makes it challenging to dissect whether such changes in the microbiome are initiating or driving factors in autoimmune liver diseases, secondary consequences of disease and/or pharmacological intervention, or alterations that modify the clinical course that patients experience. Potential mechanisms include the presence of pathobionts, disease-modifying microbial metabolites, and more nonspecific reduced gut barrier function, and it is highly likely that the effect of these change during the progression of the disease. Recurrent disease after liver transplantation is a major clinical challenge and a common denominator in these conditions, which could also represent a window to disease mechanisms of the gut-liver axis. Herein, we propose future research priorities, which should involve clinical trials, extensive molecular phenotyping at high resolution, and experimental studies in model systems. Overall, autoimmune liver diseases are characterized by an altered microbiome, and interventions targeting these changes hold promise for improving clinical care based on the emerging field of microbiota medicine.

Incidence and prevalence of primary biliary cholangitis in the Netherlands - A nationwide cohort study

Background & Aims

Although primary biliary cholangitis (PBC) is considered a rare disorder, accurate determination of its incidence and prevalence remains challenging due to limited comprehensive population-based registries. We aimed to assess the incidence and prevalence of PBC in the Netherlands over time through the nationwide Dutch PBC Cohort Study (DPCS).

Methods

DPCS retrospectively included every identifiable patient with PBC in the Netherlands from 1990 onwards in all 71 Dutch hospitals. Incidence and prevalence were assessed between 2008-2018 by Poisson regression between sex and age groups over time.

Results

On the 1st of January 2008, there were 1,458 patients with PBC in the Netherlands. Between 2008-2018, 2,187 individuals were newly diagnosed, 46 were transplanted and 468 died. The yearly incidence of PBC in 2008 was 1.38, increasing to 1.74 per 100,000 persons in 2018. When compared to those aged <45 years, females aged 45-64 years (adjusted incidence rate ratio 4.21, 95% CI 3.76-4.71, p <0.001) and males ≥65 years (adjusted incidence rate ratio 14.41, 95% CI 9.62-21.60, p <0.001) were at the highest risk of being diagnosed with PBC. The male-to-female ratio of patients newly diagnosed with PBC during the study period was 1:14 in those <45 years, 1:10 in patients aged 45-64 years, and 1:4 in those ≥65 years. Point prevalence increased from 11.9 in 2008 to 21.5 per 100,000 persons in 2018. Average annual percent change in this time period was 5.94% (95% CI 5.77-6.15, p <0.05), and was the highest among the population aged ≥65 years (5.69%, 95% CI 5.32-6.36, p <0.001).

Conclusions

In this nationwide cohort study, we observed an increase in both the incidence and prevalence of PBC in the Netherlands over the past decade, with marked age and sex differences.

Impact and implications

This nationwide Dutch primary biliary cholangitis (PBC) Cohort Study, including all hospitals in the Netherlands, showed that the incidence and prevalence of PBC have increased over the last decade. The age-dependent PBC incidence rate differed for males (highest risk ≥65 years) and females (highest risk between 45 and 65 years), which may be related to a difference in the timing of exposure to environmental triggers of PBC. The largest increase in PBC prevalence over time was observed in the population aged ≥65 years, which may have implications for the use of second-line therapies. These results therefore indicate that further studies are needed to elaborate on the advantages and disadvantages of add-on therapies in the elderly population.

Causal relationship between primary biliary cholangitis and inflammatory bowel disease: a Mendelian randomization study

Background

Several studies indicated that inflammatory bowel disease (IBD) may contribute to increased susceptibility to primary biliary cholangitis (PBC). However, the causal relationship between IBD and PBC remains unclear.

Methods

The genetic variant data of patients with IBD and PBC were obtained from published genome-wide association studies (GWASs). The IBD data were further divided into a discovery dataset and a validation dataset depending on the data source. We conducted a two-sample Mendelian randomization (MR) analysis using the inverse variance weighting (IVW), MR-Egger, weighted median (WM), MR robust adjusted profile score (MR-RAPS), and maximum likelihood (ML) methods, with IVW being the main focus, to verify the causal relationship between IBD and PBC. Additionally, a series of sensitivity analyses were performed to ensure the reliability of the results.

Results

In the discovery cohort, the IVW analysis results (OR = 1.114, P = 0.011) indicated a significant association between IBD and PBC. The MR-RAPS (OR = 1.130, P = 0.007) and ML (OR = 1.115, P = 0.011) analyses yielded results consistent with those of IVW in confirming IBD as a risk factor for PBC. In the validation cohort, consistent findings were observed regarding the causal relationship between IBD and PBC using IVW, MR-RAPS, and ML analyses; all three methods identified IBD as a risk factor for developing PBC. By the IVW analysis, Crohn's disease (CD) emerged as the most prominent subtype of IBD associated with an increased risk of developing PBC in both the discovery cohort (OR = 1.068, P = 0.049) and the validation cohort (OR = 1.082, P = 0.019).

Conclusion

The results of the MR analysis suggest a causal relationship between IBD and PBC, highlighting the necessity for proactive PBC prevention in patients with IBD, particularly those with CD.

Primary Biliary Cholangitis: Pathophysiology

Primary biliary cholangitis (PBC) is the most common of the autoimmune liver diseases, in which there is chronic small bile duct inflammation. The pathophysiology of PBC is multifactorial, involving immune dysregulation and damage to biliary epithelial cells, with influences from genetic factors, epigenetics, the gut-liver axis, and environmental exposures.

Incidence and Prevalence of Primary Sclerosing Cholangitis: A Meta-analysis of Population-based Studies

BACKGROUND

Primary sclerosing cholangitis is a chronic liver disease associated with significant morbidity, mortality, and healthcare utilization. We conducted a systematic review and meta-analysis of population-based studies of the incidence and prevalence of primary sclerosing cholangitis.

METHODS

Medline and Embase were systematically searched to identify population-based studies of a defined geographic area and reported the incidence or prevalence of primary sclerosing cholangitis in the general population. Meta-analyses, using random-effects, were performed to calculate overall and country-specific incidence (per 100 000 persons/year) and prevalence rates (per 100 000 persons) with 95% confidence intervals.

RESULTS

The 14 studies on incidence and the 12 for prevalence originated from North America, Asia, Europe, and Oceania. Incidence and prevalence rates of primary sclerosing cholangitis were 0.87 (95% confidence interval, 0.59-1.29) and 13.53 (95% confidence interval, 10.20-17.94) per 100 000 persons, respectively.

CONCLUSIONS

Both the prevalence and incidence of primary sclerosing cholangitis is low in the general population. Future studies on the incidence and prevalence of primary sclerosing cholangitis in the general population should be directed at Asia, Africa, and Latin America to allow for a more robust assessment of the global epidemiology of primary sclerosing cholangitis.

Liver transplant in primary sclerosing cholangitis: Current trends and future directions

Primary sclerosing cholangitis (PSC) is a chronic and progressive immune-mediated cholangiopathy causing biliary tree inflammation and scarring, leading to liver cirrhosis and end-stage liver disease. Diagnosis of PSC is challenging due to its nonspecific symptoms and overlap with other liver diseases. Despite the rising incidence of PSC, there is no proven medical therapy that can alter the natural history of the disease. While liver transplantation (LT) is the most effective approach for managing advanced liver disease caused by PSC, post-transplantation recurrence of PSC remains a challenge. Therefore, ongoing research aims to develop better therapies for PSC, and continued efforts are necessary to improve outcomes for patients with PSC. This article provides an overview of PSC's pathogenesis, clinical presentation, and management options, including LT trends and future aspects. It also highlights the need for improved therapeutic options and ethical considerations in providing equitable access to LT for patients with PSC. Additionally, the impact of liver transplant on the quality of life and psychological outcomes of patients with PSC is discussed. Ongoing research into PSC's pathogenesis and post-transplant recurrence is crucial for improved understanding of the disease and more effective treatment options.

Guidelines on the Diagnosis and Management of Primary Biliary Cholangitis (2021)

In 2015, the Chinese Society of Hepatology and the Chinese Society of Gastroenterology published a consensus on primary biliary cholangitis (PBC). In the past years, numerous clinical studies have been published in the field of PBC. To guide the clinical diagnosis and management of PBC patients, the Chinese Society of Hepatology invited a panel of experts to assess the new clinical evidence and formulate the current guidelines.

Primary biliary cholangitis: Epidemiology, prognosis, and treatment

Primary biliary cholangitis (PBC) is a chronic cholestatic autoimmune liver disease characterized by a destructive, small duct, and lymphocytic cholangitis, and marked by the presence of antimitochondrial antibodies. The incidence and prevalence of PBC vary widely in different regions and time periods, and although disproportionally more common among White non-Hispanic females, contemporary data show a higher prevalence in males and racial minorities than previously described. Outcomes largely depend on early recognition of the disease and prompt institution of treatment, which, in turn, are directly influenced by provider bias and socioeconomic factors. Ursodeoxycholic acid remains the initial treatment of choice for PBC, with obeticholic acid and fibrates (off-label therapy) reserved as add-on therapy for the management of inadequate responders or those with ursodeoxycholic acid intolerance. Novel and repurposed drugs are currently at different stages of clinical development not only for the treatment of PBC but also for its symptomatic management. Here, we summarize the most up-to-date data regarding the epidemiology, prognosis, and treatment of PBC, providing clinically useful information for its holistic management.

Environmental chemicals and endogenous metabolites in bile of USA and Norway patients with primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a complex bile duct disorder. Its etiology is incompletely understood, but environmental chemicals likely contribute to risk. Patients with PSC have an altered bile metabolome, which may be influenced by environmental chemicals. This novel study utilized state-of-the-art high-resolution mass spectrometry (HRMS) with bile samples to provide the first characterization of environmental chemicals and metabolomics (collectively, the exposome) in PSC patients located in the United States of America (USA) (n = 24) and Norway (n = 30). First, environmental chemical- and metabolome-wide association studies were conducted to assess geographic-based similarities and differences in the bile of PSC patients. Nine environmental chemicals (false discovery rate, FDR < 0.20) and 3143 metabolic features (FDR < 0.05) differed by site. Next, pathway analysis was performed to identify metabolomic pathways that were similarly and differentially enriched by the site. Fifteen pathways were differentially enriched (P < .05) in the categories of amino acid, glycan, carbohydrate, energy, and vitamin/cofactor metabolism. Finally, chemicals and pathways were integrated to derive exposure-effect correlation networks by site. These networks demonstrate the shared and differential chemical-metabolome associations by site and highlight important pathways that are likely relevant to PSC. The USA patients demonstrated higher environmental chemical bile content and increased associations between chemicals and metabolic pathways than those in Norway. Polychlorinated biphenyl (PCB)-118 and PCB-101 were identified as chemicals of interest for additional investigation in PSC given broad associations with metabolomic pathways in both the USA and Norway patients. Associated pathways include glycan degradation pathways, which play a key role in microbiome regulation and thus may be implicated in PSC pathophysiology.

Low vitamin D concentrations and BMI are causal factors for primary biliary cholangitis: A mendelian randomization study

Backgrounds

Observational studies have identified associations between smoking, alcohol use, body mass index (BMI), and the levels of vitamin D with primary biliary cholangitis (PBC). However, there was a lack of randomization control studies to estimate the causal relationship. This study was to investigate the causal estimates for the effects of those risk factors on PBC.

Methods

The genetic instrument variants were extracted from genome-wide association studies in European ancestry. Two-sample mendelian randomization (MR) and multivariable mendelian randomization were used to determine genetically causal estimates. Primary analyses consisted of random-effects and fix-mode inverse-variance-weighted methods, followed by secondary sensitivity analyses to verify the results.

Results

Our study showed that BMI was a causal factor for PBC (OR 1.35; 95% CI=1.03-1.77; p=0.029). In addition, we found that serum vitamin D levels had a protective effect on PBC after adjusting for BMI (OR 0.51; 95% CI=0.32-0.84; p=0.007). However, we failed to identify evidence supporting that genetic causal effect of smoking and alcohol intake were associated with PBC in European countries.

Conclusion

Our results enriched findings from previous epidemiology studies and provided evidence from MR that serum vitamin D concentrations and BMI were independent causal factors for PBC, suggesting that ensuing vitamin D sufficiency and healthy lifestyles might be a cost-effective measure for early intervention for PBC.

New insights on the role of human leukocyte antigen complex in primary biliary cholangitis

Primary Biliary Cholangitis (PBC) is a rare autoimmune cholangiopathy. Genetic studies have shown that the strongest statistical association with PBC has been mapped in the human leukocyte antigen (HLA) locus, a highly polymorphic area that mostly contribute to the genetic variance of the disease. Furthermore, PBC presents high variability throughout different population groups, which may explain the different geoepidemiology of the disease. A major role in defining HLA genetic contribution has been given by genome-wide association studies (GWAS) studies; more recently, new technologies have been developed to allow a deeper understanding. The study of the altered peptides transcribed by genetic alterations also allowed the development of novel therapeutic strategies in the context of immunotolerance. This review summarizes what is known about the immunogenetics of PBC with a focus on the HLA locus, the different distribution of HLA alleles worldwide, and how HLA modifications are associated with the pathogenesis of PBC. Novel therapeutic strategies are also outlined.

Functions of Gut Microbiota Metabolites, Current Status and Future Perspectives

Gut microbiota, a collection of microorganisms that live within gastrointestinal tract, provides crucial signaling metabolites for the physiological of hosts. In healthy state, gut microbiota metabolites are helpful for maintaining the basic functions of hosts, whereas disturbed production of these metabolites can lead to numerous diseases such as metabolic diseases, cardiovascular diseases, gastrointestinal diseases, neurodegenerative diseases, and cancer. Although there are many reviews about the specific mechanisms of gut microbiota metabolites on specific diseases, there is no comprehensive summarization of the functions of these metabolites. In this Opinion, we discuss the knowledge of gut microbiota metabolites including the types of gut microbiota metabolites and their ways acting on targets. In addition, we summarize their physiological and pathologic functions in health and diseases, such as shaping the composition of gut microbiota and acting as nutrition. This paper can be helpful for understanding the roles of gut microbiota metabolites and thus provide guidance for developing suitable therapeutic strategies to combat microbial-driven diseases and improve health.

The Role of Epigenetics in Primary Biliary Cholangitis

Primary Biliary Cholangitis (PBC) is a rare autoimmune disease of the liver, affecting mostly females. There is evidence that epigenetic changes have a pathogenic role in PBC. Epigenetic modifications are related to methylation of CpG DNA islands, post-translational modifications of histone proteins, and non-coding RNAs. In PBC, there are data showing a dysregulation of all these levels, especially in immune cells. In addition, epigenetics seems to be involved in complex phenomena such as X monosomy or abnormalities in the process of X chromosome inactivation, which have been reported in PBC and appear to influence its sex imbalance and pathogenesis. We review here historical data on epigenetic modifications in PBC, present new data, and discuss possible links among X-chromosome abnormalities at a genetic and epigenetic level, PBC pathogenesis, and PBC sex imbalance.

Environmental factors, medical and family history, and comorbidities associated with primary biliary cholangitis in Japan: a multicenter case-control study

BACKGROUND

Primary biliary cholangitis (PBC) is considered to be caused by the interaction between genetic background and environmental triggers. Previous case-control studies have indicated the associations of environmental factors (tobacco smoking, a history of urinary tract infection, and hair dye) use with PBC. Therefore, we conducted a multicenter case-control study to identify the environmental factors associated with the development of PBC in Japan.

METHODS

From 21 participating centers in Japan, we prospectively enrolled 548 patients with PBC (male/female = 78/470, median age 66), and 548 age- and sex-matched controls. These participants completed a questionnaire comprising 121 items with respect to demographic, anthropometric, socioeconomic features, lifestyle, medical/familial history, and reproductive history in female individuals. The association was determined using conditional multivariate logistic regression analysis.

RESULTS

The identified factors were vault toilet at home in childhood [odds ratio (OR), 1.63; 95% confidence interval (CI), 1.01-2.62], unpaved roads around the house in childhood (OR, 1.43; 95% CI, 1.07-1.92), ever smoking (OR, 1.70; 95% CI, 1.28-2.25), and hair dye use (OR, 1.57; 95% CI, 1.15-2.14) in the model for lifestyle factors, and a history of any type of autoimmune disease (OR, 8.74; 95% CI, 3.99-19.13), a history of Cesarean section (OR, 0.20; 95% CI, 0.077-0.53), and presence of PBC in first-degree relatives (OR, 21.1; 95% CI, 6.52-68.0) in the model for medical and familial factors.

CONCLUSIONS

These results suggest that poor environmental hygiene in childhood (vault toilets and unpaved roads) and chronic exposure to chemicals (smoking and hair dye use) are likely to be risk factors for the development of PBC in Japan.

The Epidemiology of UK Autoimmune Liver Disease Varies With Geographic Latitude

BACKGROUND & AIMS

The epidemiology of autoimmune liver disease (AILD) is challenging to study because of the diseases' rarity and because of cohort selection bias. Increased incidence farther from the Equator has been reported for multiple sclerosis, another autoimmune disease. We assessed the incidence of primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH) in relation to latitude.

METHODS

We performed a retrospective cohort study using anonymized UK primary care records from January 1, 2002, to May 10, 2016. All adults without a baseline diagnosis of AILD were included and followed up until the first occurrence of an AILD diagnosis, death, or they left the database. Latitude was measured as registered general practice rounded down to whole degrees.

RESULTS

The cohort included 8,590,421 records with 53.3 × 10⁷ years of follow-up evaluation from 694 practices. There were 1314 incident cases of PBC, 396 of PSC, and 1034 of AIH. Crude incidences were as follows: PBC, 2.47 (95% CI, 2.34-2.60); PSC, 0.74 (95% CI, 0.67-0.82); and AIH, 1.94 (95% CI, 1.83-2.06) per 100,000 per year. PBC incidence correlated with female sex, smoking, and deprivation; PSC incidence correlated with male sex and non-smoking; AIH incidence correlated with female sex and deprivation. A more northerly latitude was associated strongly with incidence of PBC: 2.16 (95% CI, 1.79-2.60) to 4.86 (95% CI, 3.93-6.00) from 50°N to 57°N (P = .002) and incidence of AIH: 2.00 (95% CI, 1.65-2.43) to 3.28 (95% CI, 2.53-4.24) (P = .003), but not incidence of PSC: 0.82 (95% CI, 0.60-1.11) to 1.02 (95% CI, 0.64-1.61) (P = .473). Incidence after adjustment for age, sex, smoking, and deprivation status showed similar positive correlations for PBC and AIH with latitude, but not PSC. Incident AIH cases were younger at more northerly latitude.

CONCLUSIONS

We describe an association in the United Kingdom between more northerly latitude and the incidence of PBC and AIH that requires both confirmation and explanation.

Environmental exposure as a risk-modifying factor in liver diseases: Knowns and unknowns

Liver diseases are considered to predominantly possess an inherited or xenobiotic etiology. However, inheritance drives the ability to appropriately adapt to environmental stressors, and disease is the culmination of a maladaptive response. Thus “pure” genetic and “pure” xenobiotic liver diseases are modified by each other and other factors, identified or unknown. The purpose of this review is to highlight the knowledgebase of environmental exposure as a potential risk modifying agent for the development of liver disease by other causes. This exercise is not to argue that all liver diseases have an environmental component, but to challenge the assumption that the current state of our knowledge is sufficient in all cases to conclusively dismiss this as a possibility. This review also discusses key new tools and approaches that will likely be critical to address this question in the future. Taken together, identifying the key gaps in our understanding is critical for the field to move forward, or at the very least to “know what we don't know.”

We Are Not Immune: Racial and Ethnic Disparities in Autoimmune Liver Diseases

Autoimmune liver diseases are attributed to a complex interplay of biologic, acquired, and environmental factors. Increased prevalence, later stage at presentation, worse response to standard therapy, and transplant-related disparities have all been reported in racial and ethnic minorities such as Black and Latinx patients with autoimmune liver diseases. While biology and inherited genetic predispositions may partly explain these disparities, definitive and universal genetic variations underlying these differences in outcomes have not been defined. Nonetheless, socioeconomic status, access to health care, environmental and societal factors, and implicit provider bias can all contribute to poor patient outcomes. There remains an unmet need to understand and mitigate the factors contributing to health inequity in autoimmune liver diseases. In this review, we summarize the data on racial and ethnic disparities in presentation, treatment response, and outcomes pertaining to autoimmune liver diseases in minority populations, on the premise that understanding disparities is the first step toward reaching health equity.

Recent advances in clinical practice: epidemiology of autoimmune liver diseases

Autoimmune liver diseases are chronic inflammatory hepatobiliary disorders that when classically defined encompass three distinctive clinical presentations; primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH). Meaningful changes in disease epidemiology are reported, with increasing incidence and prevalence of AIH and PSC in Europe, and rising prevalence of PBC across Europe, North America and the Asia-Pacific region. However, there appears to be very significant global variation with contemporary incidence rates of disease per 100 000 ranging from 0.84 to 2.75 for PBC, 0.1 to 4.39 for PSC and 0.4 to 2.39 for AIH. Prevalence corresponds, and per 100 000 estimates for PBC range from 1.91 to 40.2, for PSC between 0.78 and 31.7 and for AIH from 4.8 to 42.9. Population-based studies and multicentre observational cohort series provide improved understanding of the clinical course that patients experience, highlighting variations in presenting phenotypes geographically and temporally. Collectively, while autoimmune liver diseases are rare, the clinical burden is disproportionately high relative to population incidence and prevalence. Age, sex and race also impact clinical outcomes, and patient morbidity and mortality are reflected by high need for gastroenterology, hepatology and organ transplant services.

Recurrent Primary Sclerosing Cholangitis: Current Understanding, Management, and Future Directions

Patients with primary sclerosing cholangitis (PSC) constitute 5 to 15% of patients listed for liver transplantation worldwide. Although post-transplant outcomes are favorable, recurrent PSC (rPSC) occurs in an important subset of patients, with higher prevalence rates reported with increasing time from transplant. Given its association with poor graft outcomes and risk of retransplant, effort has been made to understand rPSC, its pathophysiology, and risk factors. This review covers these facets of rPSC and focuses on implicated risk factors including pretransplant recipient characteristics, inflammatory bowel-disease-related factors, and donor-specific and transplant-specific factors. Confirming a diagnosis of rPSC requires thoughtful consideration of alternative etiologies so as to ensure confidence in diagnosis, management, subsequent risk assessment, and counseling for patients. Unfortunately, no cure exists for rPSC; however, future large-scale efforts are underway to better characterize the natural history of rPSC and its associated risk factors with hopes of identifying potential key targets for novel therapies.

The genetic architecture of primary biliary cholangitis

Primary biliary cholangitis (PBC) is a rare autoimmune disease of the liver affecting the small bile ducts. From a genetic point of view, PBC is a complex trait and several genetic and environmental factors have been called in action to explain its etiopathogenesis. Similarly to other complex traits, PBC has benefited from the introduction of genome-wide association studies (GWAS), which identified many variants predisposing or protecting toward the development of the disease. While a progressive endeavour toward the characterization of candidate loci and downstream pathways is currently ongoing, there is still a relatively large portion of heritability of PBC to be revealed. In addition, genetic variation behind progression of the disease and therapeutic response are mostly to be investigated yet. This review outlines the state-of-the-art regarding the genetic architecture of PBC and provides some hints for future investigations, focusing on the study of gene-gene interactions, the application of whole-genome sequencing techniques, and the investigation of X chromosome that can be helpful to cover the missing heritability gap in PBC.

The methylimidazolium ionic liquid M8OI is detectable in human sera and is subject to biliary excretion in perfused human liver

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M8OI was recently found to be contaminating the environment.

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M8OI was detected in the sera from 5/20 PBC patients and 1/10 controls.

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M8OI is taken up by human liver hepatocytes.

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M8OI is sequentially metabolised by CYPs followed by oxidation by dehydrogenases.

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The final carboxylic acid metabolite COOH7IM is, in part, excreted into human bile.

A methylimidizolium ionic liquid (M8OI) was recently found to be contaminating the environment and to be related to and/or potentially a component of an environmental trigger for the autoimmune liver disease primary biliary cholangitis (PBC). The aims of this study were to investigate human exposure to M8OI, hepatic metabolism and excretion. PBC patient and control sera were screened for the presence of M8OI. Human livers were perfused with 50μM M8OI in a closed circuit and its hepatic disposition examined. Metabolism was examined in cultured human hepatocytes and differentiated HepaRG cells by the addition of M8OI and metabolites in the range 10–100 μM. M8OI was detected in the sera from 5/20 PBC patients and 1/10 controls. In perfused livers, M8OI was cleared from the plasma with its appearance – primarily in the form of its hydroxylated (HO8IM) and carboxylated (COOH7IM) products – in the bile. Metabolism was reflected in cultured hepatocytes with HO8IM production inhibited by the cytochrome P450 inhibitor ketoconazole. Further oxidation of HO8IM to COOH7IM was sequentially inhibited by the alcohol and acetaldehyde dehydrogenase inhibitors 4-methyl pyrazole and disulfiram respectively. Hepatocytes from 1 donor failed to metabolise M8OI to COOH7IM over a 24 h period. These results demonstrate exposure to M8OI in the human population, monooxygenation by cytochromes P450 followed by alcohol and acetaldehyde dehydrogenase oxidation to a carboxylic acid that are excreted, in part, via the bile in human liver.