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Loss of retinyl ester (RE)-rich lipid droplets (LDs) from hepatic stellate cells (HSCs) is cited as a key event in their cellular transdifferentiation to activated, pro-fibrotic myofibroblasts; however, it remains unclear if changes in LD morphology or RE content are causal for transdifferentiation. To better understand LD dynamics in vitro within a common model of HSC activation, we used novel approaches preserving LD morphology and allowing for quantitation of RE. The size and quantity of LDs within in vitro and in vivo bile duct ligation (BDL)-activated HSCs were quantitated using adipocyte differentiation-related protein (ADRP) labeling and oil red o (ORO) staining (gold standard), and RE content was determined using fluorescence microscopy. We found during HSC activation in vitro that LD number differed significantly when measured by ADRP and ORO, respectively ( day 1: 56 vs. 5, P = 0.03; day 4: 101 vs. 39, P = 0.03; day 14: 241 vs. 12, P = 0.02). Ex vivo HSCs activated in vivo contained the same number of LDs as day 4 in vitro activated HSCs (118 vs. 101, P = 0.54). Decline in LD RE occurred beyond day 4 in vitro and day 1 ex vivo , after HSC transdifferentiation was underway. Lastly, in situ HSCs examined using electron microscopy show LDs tend to be smaller but are ultimately retained in BDL injured livers. Therefore, we conclude that during HSC transdifferentiation, LDs are not lost but are retained, decreasing in size. Additionally, RE content declines after transdifferentiation is underway. These data suggest that these LD changes are not causal for HSC transdifferentiation.NEW & NOTEWORTHY Loss of retinoid-laden lipid droplets from hepatic stellate cells has long been held as a hallmark of their transdifferentiation into activated myofibroblasts, the dominant cells that drive hepatic fibrosis. This study demonstrates that stellate cells activated in culture and after liver injury in vivo retain their lipid droplets and that these droplets become smaller and more numerous, with decreases in droplet retinoid concentration occurring only after cellular transdifferentiation is underway.

Liver cirrhosis is a major cause of death worldwide and is characterized by extensive fibrosis. There are currently no effective antifibrotic therapies available. To obtain a better understanding of the cellular and molecular mechanisms involved in disease pathogenesis and enable the discovery of therapeutic targets, here we profile the transcriptomes of more than 100,000 single human cells, yielding molecular definitions for non-parenchymal cell types that are found in healthy and cirrhotic human liver. We identify a scar-associated TREM2

Background & Aims While abstinence-promoting behavioral and pharmacotherapies are part of the therapeutic foundation for alcohol use disorder (AUD) and alcohol-associated liver disease (ALD), these therapies, along with alcohol screening and education, are often underutilized. Our aim was to examine provider attitudes and practices for alcohol screening, treatment and education in patients with liver disease. Methods We conducted a survey of primarily (89%) hepatology and gastroenterology providers within (80%) and outside the United States (20%). Surveys were sent to 921 providers with 408 complete responses (44%), of whom 343 (80%) work in a tertiary liver transplant center. Results While alcohol screening rates in liver disease patients was nearly universal, less than half of providers reported practicing with integrated addiction providers, using alcohol biomarkers and screening tools. Safe alcohol use by liver disease patients was felt to exist by 40% of providers. While 60% of providers reported referring AUD patients for behavioral therapy, 71% never prescribed AUD pharmacotherapy due to low comfort (84%). Most providers (77%) reported low addiction education and 90% desired more during GI/hepatology fellowship training. Amongst prescribers, baclofen was preferred, but with gaps in pharmacotherapy knowledge. Overall, there was low adherence to the 2019 AASLD practice guidance for ALD, although higher in hepatologists and experienced providers. Conclusions While our survey of hepatology and gastroenterology providers demonstrated higher rates of alcohol screening and referrals for behavioral therapy, we found low rates of prescribing AUD pharmacotherapy due to knowledge gaps from insufficient education. Further studies are needed to assess interventions to improve provider alignment with best practices for treating patients with AUD and ALD.