7). The genetic deletion of Ostα leads first to alterations in bile acid homeostasis, increasing formation of Fgf15 and inhibition of Cyp7a1, resulting in a smaller bile acid pool size in these animals.1, 2 When these animals are subjected to BDL, the endocrine actions of Fgf15 are eliminated because bile acids GSK-3 activity are now excluded from

the intestine, resulting in up-regulation of bile acid synthesis and hepatic basolateral membrane bile acid export transporters. Finally, the inability of the kidney to reabsorb bile acids because of the absence of Ostα, in association with further down-regulation of Asbt and up-regulation of renal Mrp2 and Mrp4, all result in a significant escape route for bile acids in the urine that does not normally occur to this

extent in the conventional adaptive response of the kidney to cholestasis. This finding has significant therapeutic implications because strategies to down-regulate Ostα in the kidney should have major clinical benefits Ibrutinib clinical trial in cholestatic liver injury by further augmenting the renal excretion of bile acids and thus diminishing their hepatic and systemic accumulation, as shown in this study. We thank Kathy Harry for technical assistance and Christine L. Hammond for help with the collection and analysis of hepatic bile. Additional Supporting Information may be found in the online version of this article. “
“Transient hepatomegaly often accompanies acute bacterial infections. Reversible, dose-dependent hepatomegaly also occurs when animals are given intravenous infusions of bacterial lipopolysaccharide (LPS). We found that recovery from LPS-induced hepatomegaly requires a host enzyme, acyloxyacyl hydrolase (AOAH), that inactivates LPS. When we challenged Aoah−/− mice with low doses of LPS or Gram-negative bacteria, their livers remained enlarged (as much as 80% above normal) many weeks longer than did the livers of Aoah+/+

animals. When compared with livers from LPS-primed Aoah+/+ mice, LPS-primed Aoah−/− livers had (1) more numerous and larger Kupffer cells, (2) intrasinusoidal leukocyte aggregates and activated sinusoidal endothelial cells, and (3) sustained production selleck compound of interleukin (IL)-10 and messenger RNAs (mRNAs) for tumor necrosis factor (TNF), IL-10, and IRAK-M. Depleting Kupffer cells decreased the liver enlargement by ≈40%, whereas depletion of neutrophils, dendritic cells, natural killer (NK) cells, NK-T cells, or B cells had no effect. Pretreatment with dexamethasone almost completely prevented prolonged hepatomegaly in Aoah−/− mice, whereas neutralizing TNF or interleukin-1β was only partially effective. In contrast, an antagonistic antibody to the IL-10 receptor increased LPS-induced hepatomegaly by as much as 50%. Conclusion: our findings suggest that persistently active LPS induces Kupffer cells to elaborate mediators that promote the accumulation of leukocytes within enlarged sinusoids.