No abstract

Steatotic livers are more sensitive to ischemia/reperfusion (I/R) and are thus routinely rejected for transplantation because of their increased rate of primary nonfunction (PNF). Lean livers have less I/R-induced damage and inflammation due to Kupffer cells (KC), which are protective after total, warm, hepatic I/R with associated bowel congestion. This protection has been linked to KC-dependent expression of the potent anti-inflammatory cytokine interleukin-10 (IL-10). We hypothesized that pretreatment with exogenous IL-10 would protect the steatotic livers of genetically obese (ob/ob) mice from inflammation and injury induced by I/R. Lean and ob/ob mice were pretreated with either IL-10 or liposomally-encapsulated bisphosphonate clodronate (shown to deplete KC) prior to total, warm, hepatic I/R. IL-10 pretreatment increased survival of ob/ob animals at 24 hrs post-I/R from 30% to 100%, and significantly decreased serum ALT levels. At six hrs post-I/R, IL-10 pretreatment increased IL-10 mRNA expression, but suppressed up-regulation of the pro-inflammatory cytokine IL-1β mRNA. However, ALT levels were elevated at six hrs post-I/R in KC-depleted animals. These data reveal that pretreatment with IL-10 protects steatotic livers undergoing I/R, and that phagocytically active KC retain a hepatoprotective role in the steatotic environment.

Background 30-day readmissions (30DRA) are a highly scrutinized measure of healthcare quality and relatively frequent among kidney transplants (KTX). Development of predictive risk models are critical to reducing 30DRA and improving outcomes. Current approaches rely on fixed variables derived from administrative data. These models may not capture clinical evolution that is critical to predicting outcomes. Methods We directed a retrospective analysis towards: 1) developing parsimonious risk models for 30DRA and 2) comparing efficiency of models based on the use of immutable versus dynamic data. Baseline and in-hospital clinical and outcomes data were collected from adult KTX recipients between 2005 – 12. Risk models were developed using backward logistic regression and compared for predictive efficacy using ROC Curves. Results Of 1,147 KTX patients, 123 had 30DRA. Risk factors for 30DRA included recipient comorbidities, transplant factors, and index hospitalization patient level clinical data. The initial fixed variable model included 9 risk factors and was modestly predictive (AUC 0.64, 95% CI 0.58–0.69). The model was parsimoniously reduced to 6 risks, which remained modestly predictive (AUC 0.63, 95% CI 0.58–0.69). The initial predictive model using 13 fixed and dynamic variables was significantly predictive (AUC 0.73, 95% CI 0.67–0.80), with parsimonious reduction to 9 variables maintaining predictive efficacy (AUC 0.73, 95% CI 0.67–0.79). The final model using dynamically evolving clinical data outperformed the model using static variables (p=0.009). Internal validation demonstrated the final model was stable with minimal bias. Conclusion We demonstrate that modeling dynamic clinical data outperformed models utilizing immutable data in predicting 30DRA.

Growth, survival and cytoskeletal rearrangement of cardiomyocytes are critical for cardiac hypertrophy. Signal transducer and activator of transcription-3 (STAT3) activation is an important cardioprotective factor associated with cardiac hypertrophy. Although STAT3 activation has been reported via signaling through Janus Kinase 2 (JAK2) in several cardiac models of hypertrophy, the importance of other nonreceptor tyrosine kinases (NTKs) has not been explored. Utilizing an in vivo feline right ventricular pressure-overload (RVPO) model of hypertrophy, we demonstrate that in 48 h pressure-overload (PO) myocardium, STAT3 becomes phosphorylated and redistributed to detergent-insoluble fractions with no accompanying JAK2 activation. PO also caused increased levels of phosphorylated STAT3 in both cytoplasmic and nuclear fractions. To investigate the role of other NTKs, we used our established in vitro cell culture model of hypertrophy where adult feline cardiomyocytes are embedded three-dimensionally (3D) in type-I collagen and stimulated with an integrin binding peptide containing an Arg-Gly-Asp (RGD) motif that we have previously shown to recapitulate the focal adhesion complex (FAC) formation of 48 h RVPO. RGD stimulation of adult cardiomyocytes in vitro caused both STAT3 redistribution and activation that were accompanied by the activation and redistribution of c-Src and the TEC family kinase, BMX, but not JAK2. However, infection with dominant negative c-Src adenovirus was unable to block RGD-stimulated changes on either STAT3 or BMX. Further analysis in vivo in 48 h PO myocardium showed the presence of both STAT3 and BMX in the detergent-insoluble fraction with their complex formation and phosphorylation. Therefore, these studies indicate a novel mechanism of BMX-mediated STAT3 activation within a PO model of cardiac hypertrophy that might contribute to cardiomyocyte growth and survival.

Nonalcoholic steatohepatitis (NASH) is currently the third most common cause of end stage liver disease necessitating transplantation. The question remains how inflammation and NASH develop in the setting of nonalcoholic fatty liver disease (NAFLD) and steatosis. Understand the roles of toll-like receptor 4 (TLR4) and dietary fats in the development of hepatic inflammation. Wild-type and TLR4 KO mice were fed a standard high fat diet (LD), a high saturated fat diet (MD), or an isocaloric control diet (CD). Sera and tissue were analyzed for development of hepatic steatosis, inflammation, and injury. MD induced features of hepatic steatosis and inflammation in wild-type, but not in TLR4 KO, mice. TLR4 KO prevented MD induced increases in NAFLD activity scores, serum alanine aminotransferase levels, and inflammatory cytokine expression. Inflammatory cell infiltration and cytokine expression were also lower in the TLR4 KO mice livers than wild-type mice fed MD. Hepatic expression of Collagen I transcripts and collagen deposition were also decreased in the TLR4 KO MD animals. Results show that TLR4 plays a critical role in the effects of dietary fat composition on the development of hepatic steatosis, inflammation, and injury consistent with nonalcoholic steatohepatitis.