Current and promising therapy for primary biliary cholangitis

Reasons why women are more likely to develop primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune disease of biliary stasis in which immune factors cause the gradual destruction of small bile ducts, biliary stasis, and eventually the development of liver fibrosis, cirrhosis, and even liver failure. One of the main characteristics of PBC is that it primarily affects middle-aged women, but the precise cause is still unknown. This article analyzes the unique causes and mechanisms of the female predominance of PBC and summarizes the potential causes.The female domination of PBC is reported to be primarily caused by sex hormones, environmental circumstances, and epigenetic changes, each of which has a different subtle impact on patients' gender disparities.

Characteristic geoepidemiology of primary biliary cholangitis in Taiwan: A nationwide population-based study

AIM

Data on the geoepidemiology and outcomes of primary biliary cholangitis (PBC) in Asia are limited; thus, we aimed to collect and assess this information for Taiwan.

METHODS

A nationwide population-based cohort study was undertaken using data from the Taiwan National Health Insurance Research Database. Primary biliary cholangitis was defined by the International Classification of Diseases, Ninth Revision, Clinical Modification code 571.6 based on alkaline phosphatase and antimitochondrial antibody measurements and ursodeoxycholic acid treatment.

RESULTS

During 2002-2015, 2737 patients (2137 female patients; mean age, 57.78 years) had PBC. The average annual age- and sex-adjusted prevalence and incidence rates of PBC were 8.092/105 and 1.148/105 , respectively. Prevalent cases peaked in patients aged 50-59 years; the female-to-male ratio was 4.21. Annual prevalence rates increased with time (average percentage change, 12.03%; p < 0.0001). The annual incidence rates decreased with time (-7.39%; p = 0.000011) in female patients (-8.94%; p = 0.000003) but remained steady in male patients. Female-to-male and northern-to-southern relative risks of PBC incidence rates ranged from 2.2675 to 4.3318 and from 1.5707 to 3.1725, respectively. The 14-year hepatocellular carcinoma (HCC) cumulative incidence was 9.11%, and the mortality rate was 32.44%; the cumulative incidences of dyslipidemia, thyroid disease, and extrahepatic cancers were 65.13%, 24.40%, and 12.79%, respectively. Higher cumulative incidences of HCC (p = 0.0064) and mortality (p < 0.0001) were noted in male than female PBC patients; southern Taiwan PBC patients had higher cumulative incidences of mortality (p < 0.0001) than their northern counterparts.

CONCLUSION

In Taiwan, decreasing trends in incidence rates and the female-to-male ratio of PBC patients and specific sex and geographic impacts on the incidence rates and outcomes of PBC demand further investigation.

Insights Into the Involvement of Circular RNAs in Autoimmune Diseases

Circular RNAs (circRNAs) are single-stranded, endogenous, non-coding RNA (ncRNA) molecules formed by the backsplicing of messenger RNA (mRNA) precursors and have covalently closed circular structures without 5′-end caps and 3′-end polyadenylation [poly(A)] tails. CircRNAs are characterized by abundant species, stable structures, conserved sequences, cell- or tissue-specific expression, and widespread and stable presence in many organisms. Therefore, circRNAs can be used as biomarkers for the prediction, diagnosis, and treatment of a variety of diseases. Autoimmune diseases (AIDs) are caused by defects in immune tolerance or abnormal immune regulation, which leads to damage to host organs. Due to the complexity of the pathophysiological processes of AIDs, clinical therapeutics have been suboptimal. The emergence of circRNAs sheds new light on the treatment of AIDs. In particular, circRNAs mainly participate in the occurrence and development of AIDs by sponging targets. This review systematically explains the formation, function, mechanism, and characteristics of circRNAs in the context of AIDs. With a deeper understanding of the pathophysiological functions of circRNAs in the pathogenesis of AIDs, circRNAs may become reasonable, accurate, and effective biomarkers for the diagnosis and treatment of AIDs in the future.

Autophagy in liver diseases

Autophagy is the liver cell energy recycling system regulating a variety of homeostatic mechanisms. Damaged organelles, lipids and proteins are degraded in the lysosomes and their elements are re-used by the cell. Investigations on autophagy have led to the award of two Nobel Prizes and a health of important reports. In this review we describe the fundamental functions of autophagy in the liver including new data on the regulation of autophagy. Moreover we emphasize the fact that autophagy acts like a two edge sword in many occasions with the most prominent paradigm being its involvement in the initiation and progress of hepatocellular carcinoma. We also focused to the implication of autophagy and its specialized forms of lipophagy and mitophagy in the pathogenesis of various liver diseases. We analyzed autophagy not only in well studied diseases, like alcoholic and nonalcoholic fatty liver and liver fibrosis but also in viral hepatitis, biliary diseases, autoimmune hepatitis and rare diseases including inherited metabolic diseases and also acetaminophene hepatotoxicity. We also stressed the different consequences that activation or impairment of autophagy may have in hepatocytes as opposed to Kupffer cells, sinusoidal endothelial cells or hepatic stellate cells. Finally, we analyzed the limited clinical data compared to the extensive experimental evidence and the possible future therapeutic interventions based on autophagy manipulation.

Comparative transcriptome analysis of the fungus Gibberella zeae transforming lithocholic acid into ursodeoxycholic acid

The comparative transcriptome analysis of the fungus Gibberella zeae which could efficiently catalyze the 7β-hydroxylation of LCA to produce UDCA was performed with LCA induction. This is the first time to report the comparative transcriptome of fungus under LCA treatment. Totally, 1364 differentially expressed genes including 770 up-regulated and 594 down-regulated genes were identified. In the 770 up-regulated genes, 12 genes with the function of hydroxylation were picked out by application of function screening, which were annotated as CYP450 or hydroxylase. Moreover, the qRT-PCR results of five up-regulated CYP450-like genes confirmed the credibility of RNA-Seq further. These results provide valuable information for the discovery of novel enzyme producing clinical drug UDCA from butchery byproduct LCA, and also might indicate some clues for the detoxification process of LCA in humans.

Symptom Burden and Treatment Response in Patients with Primary Biliary Cholangitis (PBC)

BACKGROUND

Primary biliary cholangitis (PBC) is a chronic, cholestatic liver disease that can lead to end-stage liver disease and impairs the quality of life. At current, most data come from few large cohorts.

AIM

This cross-sectional study evaluated treatment response and symptom burden in patients with PBC in Germany to expand the available data.

METHODS

A total of 140 PBC patients were prospectively enrolled at the outpatient liver clinic of the University Medical Center in Mainz starting in June 2016. Historic and current response rates of UDCA treatment were determined using published binary models. Symptom burden was assessed using the PBC-40 questionnaire.

RESULTS

The primary treatment response ranged between 73 and 86% depending on the definition used. Importantly, this response rate was maintained over a median time of 5 years in follow-up. The highest symptom burden was observed for fatigue and emotional (2.4 ± 1; 2.3 ± 1.1 of 5), while pruritus (1.1 ± 1.1 of 5) had the lowest scores. IgG correlated with the PBC-40 domain social (r = 0.211, p = 0.032), while HDL inversely correlated with the symptom burden of pruritus (r = - 0.236; p = 0.018).

CONCLUSION

In this tertiary care cohort, 75% of the patients showed biochemical response after 1 year according to the acknowledged Paris II criteria. Patients reported a significant symptom burden, and the domain fatigue of the PBC-40 was most prominently impaired.

Ursodeoxycholic acid attenuates the expression of proinflammatory cytokines in periodontal cells

BACKGROUND

Ursodeoxycholic acid (UDCA) is one of the first-line therapeutic medications used in treatment of cholestatic liver disease. Considering that periodontitis is epidemiologically linked to liver diseases, the question arises weather UDCA holds anti-inflammatory properties on periodontal health. Herein, we provide information that support anti-inflammatory effects of UDCA on three different periodontium-related cell types.

METHODS

Gingival fibroblasts and the oral human squamous carcinoma cell line HSC-2 were exposed to interleukin (IL)1β and tumor necrosis factor (TNF)α with and without UDCA. Murine RAW 264.7 macrophages were incubated with sterile-filtered human saliva also in the presence of UDCA. The expression of inflammatory cytokines was measured by reverse transcription-polymerase chain reaction. Immunoassay was applied to detect the production of IL6. Immunostaining was performed for the p65 subunit to further support the anti-inflammatory role of UDCA.

RESULTS

We report here that UDCA significantly reduced the IL1β and TNFα-induced expression of IL1, IL6, and IL8 in gingival fibroblasts and the HSC-2 cell line. In RAW 264.7 macrophages, UDCA attenuated the expression of IL1α, IL1β, and IL6 that was increased by saliva. Immunoassay confirmed the capacity of UDCA to reduce inflammation-induced production of IL6 in gingival fibroblasts, HSC-2 and RAW 264.7 cells. Immunostaining revealed the blocking of nuclear translocation of p65 in gingival fibroblasts.

CONCLUSIONS

Taken together, UDCA can attenuate the provoked expression of inflammatory cytokines in oral fibroblasts, oral human squamous carcinoma cells and macrophages in vitro. These data support the hypothesis that patients with cholestatic liver disease might benefit from UDCA with respect to periodontal health.

Picroside II protects against cholestatic liver injury possibly through activation of farnesoid X receptor

BACKGROUD

Cholestasis, accompanied by the accumulation of bile acids in body, may ultimately cause liver failure and cirrhosis. There have been limited therapies for cholesteric disorders. Therefore, development of appropriate therapeutic drugs for cholestasis is required. Picroside II is a bioactive component isolated from Picrorhiza scrophulariiflora Pennell, its mechanistic contributions to the anti-cholestasis effect have not been fully elucidated, especially the role of picroside II on bile acid homeostasis via nuclear receptors remains unclear.

PURPOSE

This study was designed to investigate the hepatoprotective effect of picroside II against alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury and elucidate the mechanisms in vivo and in vitro.

METHODS

The ANIT-induced cholestatic mouse model was used with or without picroside II treatment. Serum and bile biochemical indicators, as well as liver histopathological changes were examined. siRNA, Dual-luciferase reporter, quantitative real-time PCR and Western blot assay were used to demonstrate the farnesoid X receptor (FXR) pathway in the anti-cholestasis effects of picroside II in vivo and in vitro.

RESULTS

Picroside II exerted hepatoprotective effect against ANIT-induced cholestasis by impaired hepatic function and tissue damage. Picroside II increased bile acid efflux transporter bile salt export pump (Bsep), uptake transporter sodium taurocholate cotransporting polypeptide (Ntcp), and bile acid metabolizing enzymes sulfate transferase 2a1 (Sult2a1) and UDP-glucuronosyltransferase 1a1 (Ugt1a1), whereas decreased the bile acid synthesis enzymes cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1). In addition, expression of FXR and the target gene Bsep was increased, whereas aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor alpha (PPARα) and their corresponding target genes were not significantly influenced by picroside II under cholestatic conditions. Furthermore, regulation of transporters and enzymes involved in bile acid homeostasis by picroside II were abrogated by FXR silencing in mouse primary cultured hepatocytes. Dual-luciferase reporter assay performed in HepG2 cells demonstrated FXR activation by picroside II.

CONCLUSION

Our findings demonstrate that picroside II exerts protective effect on ANIT-induced cholestasis possibly through FXR activation that regulates the transporters and enzymes involved in bile acid homeostasis. Picroside II might be an effective approach for the prevention and treatment of cholestatic liver diseases.