Adjunct Fenofibrate Up-regulates Bile Acid Glucuronidation and Improves Treatment Response For Patients With Cholestasis
Accumulation of cytotoxic bile acids (BAs) during cholestasis can result in liver failure. Glucuronidation, a phase II metabolism pathway responsible for BA detoxification, is regulated by peroxisome proliferator–activated receptor alpha (PPARα). This study investigates the efficacy of adjunct fenofibrate therapy to up-regulate BA-glucuronidation and reduce serum BA toxicity during cholestasis. Adult patients with primary biliary cholangitis (PBC, n = 32) and primary sclerosing cholangitis (PSC, n = 23), who experienced an incomplete response while receiving ursodiol monotherapy (13-15 mg/kg/day), defined as serum alkaline phosphatase (ALP) ≥ 1.5 times the upper limit of normal, received additional fenofibrate (145-160 mg/day) as standard of care. Serum BA and BA-glucuronide concentrations were measured by liquid chromatography–mass spectrometry. Combination therapy with fenofibrate significantly decreased elevated serum ALP (−76%, P < 0.001), aspartate transaminase, alanine aminotransferase, bilirubin, total serum BAs (−54%), and increased serum BA-glucuronides (+2.1-fold, P < 0.01) versus ursodiol monotherapy. The major serum BA-glucuronides that were favorably altered following adjunct fenofibrate include hyodeoxycholic acid–6G (+3.7-fold, P < 0.01), hyocholic acid–6G (+2.6-fold, P < 0.05), chenodeoxycholic acid (CDCA)–3G (−36%), and lithocholic acid (LCA)–3G (−42%) versus ursodiol monotherapy. Fenofibrate also up-regulated the expression of uridine 5′-diphospho-glucuronosyltransferases and multidrug resistance–associated protein 3 messenger RNA in primary human hepatocytes. Pearson’s correlation coefficients identified strong associations between serum ALP and metabolic ratios of CDCA-3G (r2 = 0.62, P < 0.0001), deoxycholic acid (DCA)-3G (r2 = 0.48, P < 0.0001), and LCA-3G (r2 = 0.40, P < 0.001), in ursodiol monotherapy versus control. Receiver operating characteristic analysis identified serum BA-glucuronides as measures of response to therapy. Conclusion: Fenofibrate favorably alters major serum BA-glucuronides, which correlate with reduced serum ALP levels and improved outcomes. A PPARα-mediated anti-cholestatic mechanism is involved in detoxifying serum BAs in patients with PBC and PSC who have an incomplete response on ursodiol monotherapy and receive adjunct fenofibrate. Serum BA-glucuronides may serve as a noninvasive measure of treatment response in PBC and PSC.