PNPLA3 p.I148M and TM6SF2 p.E167K variants do not predispose to liver injury in cholestatic liver diseases: A prospective analysis of 178 patients with PSC

Prevalence and bidirectional association between primary sclerosing cholangitis and Crohn's disease: A systematic review and meta-analysis

PURPOSE

This meta-analysis aimed to evaluating the prevalence of Crohn's disease in primary sclerosing cholangitis (PSC) and the incidence of primary sclerosing cholangitis in Crohn's disease (CD), along with their interrelation.

METHODS

An extensive search was conducted in the PubMed and Embase to identify available publications up to December 2023. Studies were included if they reported the prevalence of CD in PSC patients, or vice versa. Proportions were assessed using the DerSimonian and Laird method, followed by transformation via the Freeman-Tukey double inverse sine transformation. The quality of the included studies utilizing the Joanna Briggs Institute Critical Appraisal Checklist.

RESULTS

Based on quantitative analysis of 61 studies, the prevalence of PSC in patients with CD was 0.88% (95% CI: 0.53-1.30%). The prevalence of PSC in male CD patients was 0.45% (95% CI: 0.03-1.16%). In female CD patients, the prevalence was 0.51% (95% CI: 0.09-1.14%). The prevalence of CD with PSC was 11.27% (95% CI: 9.56-13.10%). The prevalence of CD in male PSC patients was 10.71% (95% CI: 7.42-14.50%). Among female PSC patients, the pooled prevalence of CD was 13.05% (95% CI: 11.05-15.19%).

CONCLUSIONS

We found a significant bidirectional association between PSC and CD, with a higher prevalence of CD in female with PSC compared to male. These findings provide important epidemiological data for clinical practice.

PNPLA3 allele frequency has no impact on biliary bile acid composition or disease course in patients with primary sclerosing cholangitis

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease that leads to bile duct strictures, cholestasis, and biliary cirrhosis. PNPLA3 (patatin-like phospholipase domain containing 3), regulates cellular lipid synthesis by converting lysophosphatidic acid into phosphatidic acid. Isoleucine mutation to methionine at position 148 (I148M) causes a loss of this function. Only two studies, with contradictory results, have evaluated the role of PNPLA3 in PSC. The rs738409(G) variant of PNPLA3 has been associated with an increased risk for transplantation in male patients with dominant strictures (DS). The study aimed to evaluate the PNPLA3 allele frequency effect on the clinical outcomes, progression, and prognosis of PSC. Furthermore, we analyzed the impact of PNPLA3 on phospholipid and bile acid composition to evaluate the effect of the PNPLA3 status on UDCA response.

PATIENTS AND METHODS

We recruited 560 patients prospectively and collected clinical and laboratory data as well as liver histology and imaging findings. PNPLA3 (CC, CG, GG) alleles were analyzed with TaqManTM. We also analyzed bile acids (BA), cholesterol and phospholipids and individual BA from a sample aspirated during endoscopic retrograde cholangiography (ERC).

RESULTS

Among the recruited patients, 58.4%, 35.7% and 5.9% had the wild (CC), heterozygous (CG) and homozygous (GG) alleles, respectively. The PNPLA3 haplotype did not impact bile composition or individual BA. In addition, we found no differences in age at diagnosis, disease progression, liver fibrosis or survival between the cohorts.

CONCLUSIONS

The PNPLA3 I148M variant had no significant impact on on bile composition, including UDCA content, clinical outcomes, progression of liver fibrosis, hepatobiliary cancer risk, liver transplantation, or overall survival.

A common variant in the hepatobiliary phospholipid transporter ABCB4 modulates liver injury in PBC but not in PSC: prospective analysis in 867 patients

BACKGROUND

The ATP-binding cassette subfamily B member 4 (ABCB4) gene encodes the hepatic phospholipid transporter. Variants in the ABCB4 gene are associated with various cholestatic phenotypes, some of which progress to liver fibrosis and cirrhosis. The aim of our study was to investigate the role of the cholestasis-associated variant ABCB4 c.711A > T (p.I237I, rs2109505) in patients with primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC).

RESULTS

Two cohorts of Polish patients took part in this study. The Szczecin cohort comprised 196 patients with PBC (174 females, 38% with cirrhosis) and 135 patients with PSC (39 females, 39% with cirrhosis). The Warsaw cohort consisted of 260 patients with PBC (241 females, 44% with cirrhosis) and 276 patients with PSC (97 females, 33% with cirrhosis). Two control cohorts-150 healthy blood donors and 318 patients without liver disease, were recruited in Szczecin and in Warsaw, respectively. The ABCB4 c.711A > T polymorphism was genotyped using TaqMan assay. In both PBC cohorts, carriers of the risk variant presented more frequently with cirrhosis (Szczecin: OR = 1.841, P = 0.025; Warsaw: OR = 1.528, P = 0.039). The risk allele was associated with increased serum AST, GGT and ALP (all P < 0.05) at inclusion. During the follow-up, patients in both cohorts significantly improved their laboratory results, independently of their ABCB4 c.711A > T genotype (P > 0.05). During 8 ± 4 years follow-up, a total of 22 patients in the Szczecin PBC group developed cirrhosis, and this risk was higher among carriers of the risk variant (OR = 5.65, P = 0.04). In contrast to PBC, we did not detect any association of ABCB4 c.711A > T with a liver phenotype in PSC cohorts.

CONCLUSIONS

The frequent pro-cholestatic variant ABCB4 c.711A > T modulates liver injury in PBC, but not in PSC. In particular, carriers of the major allele are at increased risk of progressive liver scarring.

Prevalence of inflammatory bowel disease in patients with primary sclerosing cholangitis: A systematic review and meta-analysis

BACKGROUND AND AIM

Previous studies have established an association between primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis (UC). The disease burden of IBD in PSC patients was not well estimated. The study aimed to quantify the pooled prevalence of IBD in PSC and to investigate whether subtypes of PSC and sex influence the prevalence of IBD.

METHODS

PubMed, Embase, and Web of Science were searched through November 2021 for studies reporting data on IBD among PSC patients. The outcomes were the prevalence of IBD in patients with PSC, as well as the association (odds ratio [OR]) of IBD in PSC according to subtype and sex.

RESULTS

Based on the analysis of 25 studies, the prevalence of IBD in patients with PSC was 71.1% (95% CI 68.2-75.1%), most commonly in UC (55.9%, 95% CI 52.5-59.3%). The pooled prevalence of IBD was 76.9% in Australia (95% CI 71.2-82.6%, 1 study), 75.9% (95% CI 69.5-82.3%, 4 studies) in North America, 70.9% (95% CI 65.8-76.0%, 17 studies) in Europe and 67.0% (95% CI 57.9-76.0%, 2 studies) in Asia. Male PSC patients had a higher prevalence of IBD (OR 1.67, 95% CI 1.52-1.83) and UC (OR 2.02, 95% CI 1.56-2.63) and a lower prevalence of CD (OR 0.77, 95% CI 0.67-0.88) than female patients. Large duct PSC patients had a higher prevalence of IBD (OR 2.57, 95% CI 2.03-3.25) and UC (OR 4.51, 95% CI 1.22-16.71) than small duct PSC patients.

CONCLUSIONS

The study provided the first pooled estimates of the burden of IBD in patients with PSC and could be used as the basis for risk stratification of PSC patients.

Novel therapeutic targets for cholestatic and fatty liver disease

Cholestatic and non-alcoholic fatty liver disease (NAFLD) share several key pathophysiological mechanisms which can be targeted by novel therapeutic concepts that are currently developed for both areas. Nuclear receptors (NRs) are ligand-activated transcriptional regulators of key metabolic processes including hepatic lipid and glucose metabolism, energy expenditure and bile acid (BA) homoeostasis, as well as inflammation, fibrosis and cellular proliferation. Dysregulation of these processes contributes to the pathogenesis and progression of cholestatic as well as fatty liver disease, placing NRs at the forefront of novel therapeutic approaches. This includes BA and fatty acid activated NRs such as farnesoid-X receptor (FXR) and peroxisome proliferator-activated receptors, respectively, for which high affinity therapeutic ligands targeting specific or multiple isoforms have been developed. Moreover, novel liver-specific ligands for thyroid hormone receptor beta 1 complete the spectrum of currently available NR-targeted drugs. Apart from FXR ligands, BA signalling can be targeted by mimetics of FXR-activated fibroblast growth factor 19, modulation of their enterohepatic circulation through uptake inhibitors in hepatocytes and enterocytes, as well as novel BA derivatives undergoing cholehepatic shunting (instead of enterohepatic circulation). Other therapeutic approaches more directly target inflammation and/or fibrosis as critical events of disease progression. Combination strategies synergistically targeting metabolic disturbances, inflammation and fibrosis may be ultimately necessary for successful treatment of these complex and multifactorial disorders.

Genetic aspects of adult and pediatric autoimmune hepatitis: A concise review

Autoimmune Hepatitis (AIH) is a heterogenous, mostly chronic liver disease that affects people of all age groups, women more often than men. The aim of therapy is to prevent cirrhosis, as it mainly accounts for liver-related mortality in patients with AIH. Rates of remission are high in patients with AIH, but life-long immunosuppressive therapy is required. AIH is hypothesized to originate from immunologic reactivity targeted against mostly unknown self-antigens, potentially triggered by viral infections among other factors. While AIH does not follow a Mendelian inheritance pattern, part of the risk of developing AIH or worse disease course, is attributed to specific genetic risk factors. Major associations for the risk of development of AIH were found for HLA-DRB1*03:01 and HLA-DRB1*04:01 in adult AIH in the only genome-wide association study on AIH. However, other potential risk loci in SH2B3, CARD10 and KIR genes were described. This review covers the current knowledge on genetic risk factors in adult and pediatric AIH.

The roles of transmembrane 6 superfamily member 2 rs58542926 polymorphism in chronic liver disease: A meta-analysis of 24,147 subjects

Background

Some genetic association studies tried to investigate potential associations of transmembrane 6 superfamily member 2 (TM6SF2) polymorphisms with chronic liver disease. However, the results of these studies were not consistent. Thus, we performed the present meta‐analysis to explore associations between TM6SF2 polymorphisms and chronic liver disease in a larger pooled population.

Methods

Systematic literature research of PubMed, Web of Science, Embase, and CNKI was performed to identify eligible studies for pooled analyses. I² statistics were employed to assess between‐study heterogeneities. If I² was greater than 50%, random‐effect models (REMs) would be used to pool the data. Otherwise, fixed‐effect models (FEMs) would be applied for synthetic analyses.

Results

Totally 28 studies were included for analyses (13,137 cases and 11,010 controls). The pooled analyses showed that rs58542926 polymorphism was significantly associated with chronic liver disease in overall population (dominant model: p < 0.0001, OR = 0.70, 95% CI = 0.64–0.76, I² = 47%; recessive model: p < 0.0001, OR = 2.94, 95% CI = 2.05–4.20, I² = 0%; over‐dominant model: p < 0.0001, OR = 1.34, 95% CI = 1.23–1.47, I² = 0%; allele model: p < 0.0001, OR = 0.68, 95% CI = 0.63–0.73, I² = 47%), and these significant findings were further confirmed in both Asians and Caucasians. Stratified analyses by type of disease revealed similar positive results in hepatocellular carcinoma (HCC), cirrhosis, alcoholic liver disease (ALD) and NAFLD (Nonalcoholic fatty liver disease), but not in chronic hepatitis B infection (CHB) and chronic hepatitis C infection (CHC).

Conclusions

These results suggested that TM6SF2 rs58542926 could be used to identify individuals at higher susceptibility to chronic liver disease, especially for HCC, cirrhosis, ALD, and NAFLD.