Hydroxysteroid 17ß-dehydrogenase 11 accumulation on lipid droplets promotes ethanol-induced cellular steatosis.

Lipid droplets (LDs) are fat-storing organelles enclosed by a phospholipid monolayer, which harbors membrane-associated proteins that regulate distinct LD functions. LD proteins are degraded by the ubiquitin-proteasome system (UPS) and/or by lysosomes. Because chronic ethanol (EtOH) consumption diminishes the hepatic functions of the UPS and lysosomes, we hypothesized that continuous EtOH consumption slows the breakdown of lipogenic LD proteins targeted for degradation, thereby causing LD accumulation. Here, we report that LDs from livers of EtOH-fed rats exhibited higher levels of polyubiquitylated-proteins, linked at either lysine 48 (directed to proteasome) or lysine 63 (directed to lysosomes) than LDs from pair-fed control rats. MS proteomics of LD proteins, immunoprecipitated with UB remnant motif antibody (K-ε-GG), identified 75 potential UB proteins, of which 20 were altered by chronic EtOH administration. Among these, hydroxysteroid 17ß-dehydrogenase 11 (HSD17ß11) was prominent. Immunoblot analyses of LD fractions revealed that EtOH administration enriched HSD17ß11 localization to LDs. When we overexpressed HSD17ß11 in EtOH-metabolizing VA-13 cells, the steroid dehydrogenase 11 became principally localized to LDs, resulting in elevated cellular triglycerides (TGs). Ethanol exposure augmented cellular TG, while HSD17ß11 siRNA decreased both control and EtOH-induced TG accumulation. Remarkably, HSD17ß11 overexpression lowered the LD localization of adipose triglyceride lipase. EtOH exposure further reduced this localization. Reactivation of proteasome activity in VA-13 cells blocked the EtOH-induced rises in both HSD17ß11 and TGs. Our findings indicate that EtOH exposure blocks HSD17ß11 degradation by inhibiting the UPS, thereby stabilizing HSD17ß11 on LD membranes, to prevent lipolysis by adipose triglyceride lipase and promote cellular LD accumulation.

Gastrointestinal Bleeding With Left Ventricular Assist Devices (LVAD): Locating the Leak and Identifying Outcomes.

BACKGROUND AND GOALS: Gastrointestinal bleeding (GIB) is a significant complication following left ventricular assist device (LVAD) implantation. We evaluated the incidence, predictors, endoscopic findings, and outcomes of GIB in LVAD recipients. STUDY: Retrospective review of 205 adult patients undergoing HeartMate II LVAD implantation from January 2012 to June 2016. Patients were reviewed and separated into GIB (n=57; 28%) and non-GIB (n=148; 72%) groups. RESULTS: Median time to GIB was 55 (range, 3 to 730) days. The GIB group patients were older (61±12 vs. 56±13, P=0.0042), more often underwent concomitant tricuspid valve (TV) repair (16% vs. 4%, P=0.007), and a higher percentage were assigned for destination therapy (75% vs. 55%, P=0.01). Angioectasia (33%) was the most common identified cause of GIB. Median time to endoscopic intervention was 1 day. The total number of hospital readmissions after LVAD was higher in the GIB group (median of 5 vs. 3, P=0.001), as was the total number of blood products transfused after LVAD (29 vs. 13, P≤0.0001). GIB was associated with an increased risk of death (hazard ratio, 1.94; 95% confidence interval, 1.16-3.25; P=0.01) and the mortality rate during hospitalization for GIB was 11% (P=0.0004). Receiving a heart transplant was associated with a decreased hazard of death (hazard ratio, 0.40; 95% confidence interval, 0.19-0.85; P=0.016). CONCLUSIONS: Older age and destination therapy as implant strategy were found to be associated with an increased risk of GIB, consistent with previous studies. A unique finding in our study is the association of TV repair with a higher incidence of GIB. Further studies are needed to investigate possible mechanisms by which TV repair increases the incidence of GIB.