Pharmacological ASBT inhibition attenuates cholestatic liver and bile duct injury by reducing biliary BA concentrations in mice.

Angiogenesis is a key feature of liver fibrosis. Although sinusoidal remodeling is believed to contribute to fibrogenesis, the impact of sinusoidal angiogenesis on the resolution of liver fibrosis remains undefined. Myeloid cells, particularly macrophages, constantly infiltrate the fibrotic liver and can profoundly contribute to remodeling of liver sinusoids. We observe that the development of fibrosis is associated with decreased hepatic vascular endothelial growth factor (VEGF) expression as well as sinusoidal rarefication of the fibrotic scar. In contrast, the resolution of fibrosis is characterized by a rise in hepatic VEGF levels and revascularization of the fibrotic tissue. Genetic ablation of VEGF in myeloid cells or pharmacological inhibition of VEGF receptor 2 signaling prevents this angiogenic response and the resolution of liver fibrosis. We observe increased expression of matrix metalloproteases as well as decreased expression of tissue inhibitor of metalloproteases confined to sinusoidal endothelial cells in response to myeloid cell VEGF. Remarkably, reintroduction of myeloid cell–derived VEGF upon recovery restores collagenolytic acitivity and the resolution of fibrosis. Conclusion: We identify myeloid cell–derived VEGF as a critical regulator of extracellular matrix degradation by liver endothelial cells, thereby unmasking an unanticipated link between angiogenesis and the resolution of fibrosis. (Hepatology 2015;61:2042–2055)

Purpose of review Despite the plethora of publications discussing the severe respiratory coronavirus 2 (SARS-CoV-2), evidence of viral secretion in urine is sparse. Recent findings We could identify 34 publications including a total of 2172 patients. Among those, 549 patients were tested for SARS-CoV-2 secretion in urine, which was detected in only 38 patients (6.9%). Within the seven studies displaying positive results, the majority of positive patients (86.8%) was from not yet peer-reviewed studies including weak data and heterogeneous techniques for sample testing. Furthermore, none of the studies available in the literature addressed the virulence of detected viral RNA in urine. Summary Overall, only seven studies were able to detect SARS-CoV-2 secretion in urine, all of them with a considerably low rate of positivity. However, these studies were of rather low quality considering their methodology. Despite this, as SARS-CoV-2 has been detected in urine, it is of importance to discuss safety and urinary hygiene protocols. Until further research provides valid data on viral shedding and virulence in urine, potential risk of transmission through urine cannot be ruled out. Therefore, safety and hygiene measures need to be discussed.

BackgroundThe Wnt/β-catenin signaling pathway plays a crucial role in embryonic development, tissue homeostasis, wound healing and malignant transformation in different organs including the liver. The consequences of continuous β-catenin signaling in hepatocytes remain elusive.ResultsLivers of Ctnnb1CA hep mice were characterized by disturbed liver architecture, proliferating cholangiocytes and biliary type of fibrosis. Serum ALT and bile acid levels were significantly increased in Ctnnb1CA hep mice. The primary bile acid synthesis enzyme Cyp7a1 was increased whereas Cyp27 and Cyp8b1 were reduced in Ctnnb1CA hep mice. Expression of compensatory bile acid transporters including Abcb1, Abcb4, Abcc2 and Abcc4 were significantly increased in Ctnnb1CA hep mice while Ntcp was reduced. Accompanying changes of bile acid transporters favoring excretion of bile acids were observed in intestine and kidneys of Ctnnb1CA hep mice. Additionally, disturbed bile acid regulation through the FXR-FGF15-FGFR4 pathway was observed in mice with activated β-catenin.Materials and MethodsMice with a loxP-flanked exon 3 of the Ctnnb1 gene were crossed to Albumin-Cre mice to obtain mice with hepatocyte-specific expression of a dominant stable form of β-catenin (Ctnnb1CA hep mice). Ctnnb1CA hep mice were analyzed by histology, serum biochemistry and mRNA profiling.ConclusionsExpression of a dominant stable form of β-catenin in hepatocytes results in severe cholestasis and biliary type fibrosis.