Severe Unresolved Cholestasis Due to Unknown Etiology Leading to Early Allograft Failure Within the First 3 Months of Liver Transplantation

β-Sitosterol protects against lithocholic acid-induced hepatotoxicity and cholestasis via farnesoid X receptor-mediated regulation of transporters and enzymes in vitro and in vivo

Cholestasis arises as a clinical syndrome triggered by the accumulation and aggregation of bile acids. Currently, there are only a few treatment options available for cholestasis. Therefore, it is necessary to explore novel therapeutic strategies. β-sitosterol (SIT), the phytosterol most abundantly found in plants, exhibits diverse pharmacological activities. This study examined SIT's protective role against hepatotoxicity and cholestasis induced by lithocholic acid (LCA). LCA was administered twice a day to male C57BL/6 mice for four days to cause hepatotoxicity and cholestasis. Assessment of the improvement in cholestasis following SIT treatment used H&E staining and serum biomarkers. Mice hepatocyte culture, real-time PCR, immunofluorescence staining, and Western blot were utilized to clarify the mechanisms of SIT hepatoprotection. Furthermore, molecular docking and dual-luciferase reporter gene analysis were utilized to show that SIT would activate the farnesoid X receptor (FXR). In vivo, SIT reduced bile acid accumulation by inducing the bile salt export pump (Bsep), multidrug resistance-related protein 2 (Mrp2), and reduced hepatic uptake of bile acids by inhibiting Na+/taurocholate co-transporting polypeptide (Ntcp), and cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1) while in vitro, it restored FXR expression and transcriptional activity. Besides, SIT decreased hepatic inflammation by suppressing the inflammatory genes NF-κB p65 and p-NF-κB p65, TNF-α, IL-6, and IL-1β. However, the hepatoprotective effects of SIT were abolished by the FXR antagonist guggulsterone in vivo and FXR siRNA in vitro, confirming FXR-dependent mechanisms. In conclusion, SIT protects against LCA-induced hepatotoxicity and cholestasis via FXR activation. These findings highlight SIT as a promising therapeutic candidate for cholestasis.

β-sitosterol protects against ANIT-induced hepatotoxicity and cholestasis via FXR activation

Cholestasis, a condition marked by bile acid accumulation in the liver and body systems, leads to liver dysfunction and cirrhosis. Currently, ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) are the only two FDA-approved drugs for Cholestasis. Thus, new therapeutic approaches need to be developed. In this study, we validated the liver-protective properties of β-sitosterol (SIT), a key bioactive element abundant in plants, against hepatic toxicity and cholestasis induced by alpha-naphthylisothiocyanate(ANIT), while elucidating its mechanisms of action both in vivo and in vitro. SIT's FXR activation was confirmed via molecular docking and dual-luciferase assays. In the mechanisms of SIT hepatoprotection, the expression levels of bile salt export pump (Bsep) and multidrug resistance protein2 (Mrp2) which are bile acid efflux transporter, and sulfate transferase 2a1 (Sult2a1) which is a bile acid metabolizing enzyme were all increased by SIT, whereas the expression of uptake transporter sodium taurocholate transporting polypeptide (Ntcp), bile acid synthesis enzyme cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1) was decreased by SIT. In addition, SIT alleviated liver inflammation by suppressing inflammatory factor expression. However, FXR antagonist guggulsterone and FXR siRNA abolished SIT's improvements in liver histology, bile acid transporters, and enzymes. Conclusively, through activating FXR, SIT provides a protective effect against hepatotoxicity and cholestasis. SIT might serve as a new potential therapeutic strategy for the treatment of cholestatic liver diseases.

Cholangitis lenta: An underdiagnosed lesion associated with severe cholestasis following liver transplantation

BACKGROUND

Cholangitis lenta (CL) represents a specific histological lesion associated with severe cholestasis and related to sepsis. Despite being well known by pathologists, CL has been poorly studied in liver transplantation (LT).

METHODS

We performed a retrospective 12-year analysis of the incidence, risk factors, and outcome of CL in LT recipients. Biopsy samples performed within 3 months after LT underwent blinded rereading to identify recipients with CL.

RESULTS

Among 587 LT performed, 45 (7.7%) developed CL. Of these, 7 (15.6%) had no signs of clinical sepsis at the time of biopsy, but further investigations revealed positive cultures. Independent factors associated with CL were sepsis at the time of LT (OR = 3.62 [95%CI = 1.63-8.06]), donor age (OR = 1.05 [1.03-1.08]), and operative time (OR = 1.23 [95%CI = 1.02-1.48]). Cholangitis lenta was associated with increased severe morbidity (71.1% vs 33.0%, P < .001), 90-day mortality (24.4% vs 5.9%, P < .001) and decreased one-year graft (62.1% vs 89.4%, P < .001) and patient survival (55.6% vs 87.9%, P < .001).

CONCLUSION

Cholangitis lenta represents a possible lesion associated with cholestasis after LT, which strongly affects its outcome. In the event of an unexplained post-transplant cholestasis, the diagnosis of CL must be considered, even in the absence of clinically evident sepsis.