Anticholestatic mechanisms of obeticholic acid (OCA) IN lipoplysaccharide (LPS)-induced cholestasis in the rat

RAZORI M.V.; MARTÍN P.L.; BAROSSO I.R.; MEDEOT A.C.; CIRIANI N.; ANDERMATTEN R.; SCHUCK V.S.; SALAS G.; BASIGLIO C.L.; RUIZ M.L.; ROMA M.G.

Modalidad virtual

Congreso; Reunión de Sociedades de Biociencias (SAIC, SAI, AAFE) 2021.; 2021

Sociedad Argentina de Investigación Clínica,

Sepsis-induced cholestasis is due the release of inflammatory cytokines induced by LPS from Gram (-) bacteria, which impair expression/localization of hepatocellular transporters. There is no therapy for this condition. OCA is a potent FXR agonist used to treat humaninflammatory chronic cholestasis. We ascertained here its anticholestatic mechanisms in LPS-induced cholestasis.Methods: Male Wistar rats were randomized in Control, OCA (20 mg/Kg/day, i.p., 6 days), LPS (6.5 mg/Kg, i.p., last 2 days) and OCA+LPS groups. Then, we assessed serum alkaline phosphatase (ALP), a surrogate of bile salt (BS) hepatic accumulation, and taurocholate-stimulated BS output (BSO). mRNA/protein levels of Bsep and Mrp3 (apical and sinusoidal BS efflux pumps, respectively) and Ntcp (BS uptake carrier) were assessed by either or both Real time PCR and Western blot. Bsep localization was assessed by immunohistochemistryfollowed by confocal microscopy and image analysis. The inflammatory cytokines TNF-α and IL-1β were measured in serum by ELISA.Results: (*p<0.05 vs. control; #p<0.05 vs. LPS). OCA reduced ALP (U/L) in LPS-treated rats (193 ± 18# vs. 338 ± 72*), and improved BSO (nmol/g liver) (1274 ± 152 vs. 896 ± 86). This was due to an increase in the % of Bsep in the apical membrane (104 ± 13# vs. 52 ± 9*), a finding confirmed by image analysis of confocal images (p<0.001). OCA also halted the elevations (pg/ml) of TNF-α (266 ± 56*# vs. 860 ± 153*) and IL-1β (13 ± 2# vs. 52 ± 8*). Neither the drop in Ntcp (46 ± 11* vs. 52 ± 9*) nor the increase in Mrp3 (279 ± 29* vs. 299 ± 60*) expression induced by LPS (% of control) was affected.Conclusions: LPS impairs BSO, leading to BS accumulation (cholestasis). OCA prevented this by improving apical Bsep localization and the subsequent BSO; the adaptive BS urinary elimination afforded by the impaired uptake and the increased sinusoidal efflux of BSs was maintained. Counteraction of cytokine elevations may be crucial for OCA beneficial effects.