Demographic and socioeconomic factors influencing disparities in prevalence of alcohol-related injury among underserved trauma patients in a safety-net hospital.

BACKGROUND: Alcohol-related trauma remains high among underserved patients despite ongoing preventive measures. Geographic variability in prevalence of alcohol-related injury has prompted reexamination of this burden across different regions. We sought to elucidate demographic and socioeconomic factors influencing the prevalence of alcohol-related trauma among underserved patients and determine alcohol effects on selected outcomes. METHODS: A retrospective analysis examined whether patients admitted to a suburban trauma center differed according to their blood alcohol concentration (BAC) on admission. Patients were stratified based on their BAC into four categories (undetectable BAC, BAC 1-99mg/dL, BAC 100-199mg/dL, and BAC ≥ 200mg/dL). T-tests and X2 tests were used to detect differences between BAC categories in terms of patient demographics and clinical outcomes. Multivariate linear and logistic regressions were used to investigate the association between patient variables and selected outcomes while controlling for confounders. RESULTS: One third of 738 patients analyzed were BAC-positive, mean (SD) BAC was 211.4 (118.9) mg/dL, 80% of BAC-positive patients had levels ≥ 100mg/dL. After risk adjustments, the following patient characteristics were predictive of having highly elevated BAC (≥200mg/dL) upon admission to the Trauma Center; Hispanic patients (adjusted odds ratio (OR)=1.91, 95% confidence interval (CI): 1.14-3.21), unemployment (OR=1.74, 95% CI: 1.09-2.78), Medicaid beneficiaries (OR=3.59, 95% CI: 1.96-6.59), and uninsured patients (OR=2.86, 95% CI: 1.60-5.13). Patients with BAC of 100-199mg/dL were likely to be more severely injured (P=0.016) compared to undetectable-BAC patients. There was no association between being intoxicated, and being ICU-admitted or having differences in length of ICU or hospital stay. CONCLUSION: Demographic and socioeconomic factors underlie disparities in the prevalence of alcohol-related trauma among underserved patients. These findings may guide targeted interventions toward specific populations to help reduce the burden of alcohol-related injury.

Glycogen synthase kinase 3 regulates IL-1ß mediated iNOS expression in hepatocytes by down-regulating c-Jun.

Excessive nitric oxide from the inducible nitric oxide synthase (iNOS) increases shock-induced hepatic injury, hepatic dysfunction, inflammation, and mortality in animal models. Cytokines increase the expression of iNOS in hepatocytes, but the signaling mechanisms involved are not completely understood. We have previously demonstrated that Akt mediates the inhibitory effect of cAMP and insulin on cytokine-induced hepatocyte iNOS expression. We hypothesized that glycogen synthase kinase 3 (GSK3), a target of Akt phosphorylation, would regulate hepatocyte iNOS expression. In cultured rat hepatocytes, GSK3 inhibitors decreased IL-1ß mediated nitric oxide (NO) production and iNOS protein expression, while the phosphatidylinositol 3-kinase (PI3K)/Akt pathway inhibitor LY294002 increased the cytokine-mediated NO production and iNOS expression. Over-expression of the constitutively active form of GSK3ß enhanced IL-1ß-mediated iNOS expression. GSK3 catalyzes the phosphorylation of c-Jun at the c-terminal Thr239 that facilitates c-Jun degradation. Inhibition of GSK3 with SB216763 and lithium chloride significantly reduced, whereas blocking PI3K/Akt increased phosphorylation of c-Jun at Thr239. The levels of total-c-Jun and c-Jun phosphorylated at Ser63 inversely correlated with c-Jun phosphorylated at Thr239, GSK3 activation and iNOS expression. Over-expression of a dominant negative c-Jun not only caused an increase in IL-1ß-mediated iNOS promoter activity and iNOS protein expression but was also able to reverse the SB216763-mediated suppression of iNOS. These results demonstrate that GSK3, a downstream target of Akt, regulates IL-1ß-stimulated iNOS expression in hepatocytes by directly phosphorylating c-Jun in an inhibitory manner.

17ß-Estradiol attenuates cytokine-induced nitric oxide production in rat hepatocyte.

OBJECTIVE: Nitric oxide (NO) regulation during shock and sepsis is complex. NO production by endothelial NO synthase maintains microvascular perfusion and prevents shock-induced organ injury. However, the overproduction of NO by inducible NO synthase (iNOS) contributes to liver dysfunction after shock and is associated with increased tissue damage and mortality. Estrogen improves organ function and outcome after shock and sepsis, but the mechanism is unknown. We hypothesized that 17ß-estradiol would improve organ function by regulating the production of hepatocyte NO. METHODS: Isolated rat hepatocytes were stimulated in vitro with pro-inflammatory cytokines to induce NO synthesis with or without estrogen. Nitrite was detected after 24 hours. INOS protein was determined using Western blot analysis. RESULTS: Cytokine stimulation increased nitrite and iNOS protein in a dose-dependent manner. The cytokine-induced nitrite increase was significantly decreased by estrogen. iNOS expression was also diminished in cultures with the higher doses of estrogen. CONCLUSION: 17ß-Estradiol decreases cytokine-stimulated iNOS expression and NO production. The down-regulation of iNOS expression may account for the beneficial role of estrogens in models of sepsis and shock.