Upper gastrointestinal bleeding in severely burned patients: a case-control study to assess risk factors, causes, and outcome.

BACKGROUND/AIMS: To determine the risk factors, causes, and outcome of clinically important upper gastrointestinal bleeding that occurs in severely burned patients. METHODOLOGY: The charts of all patients admitted to the burn intensive care unit were analyzed retrospectively over a 4-year period (from January 2006 to December 2009). Cases consisted of burned patients who developed upper gastrointestinal bleeding more than 24 hours after admission to the burn intensive care unit. Controls were a set of patients, in the burn intensive care unit, without upper gastrointestinal bleeding matched with cases for age and gender. Cases and controls were compared with respect to the risk factors of upper gastrointestinal bleeding and outcomes. RESULTS: During the study period, clinically important upper gastrointestinal bleeding occurred in 20 patients out of all 964 patients. The most common cause of upper gastrointestinal bleeding was duodenal ulcer (11 of 20 cases, 55%). In the multivariate analysis, mechanical ventilation (p = 0.044) and coagulopathy (p = 0.035) were found to be the independent predictors of upper gastrointestinal bleeding in severely burned patients. CONCLUSIONS: Upper gastrointestinal hemorrhage tends to occur more frequently after having prolonged mechanical ventilation and coagulopathy.

Pravastatin activates the expression of farnesoid X receptor and liver X receptor alpha in Hep3B cells.

BACKGROUND: Statins are suggested to preserve gallbladder function by suppressing pro-inflammatory cytokines and preventing cholesterol accumulation in gallbladder epithelial cells. They also affect cross-talk among the nuclear hormone receptors that regulate cholesterol-bile acid metabolism in the nuclei of hepatocytes. However, there is controversy over whether or how statins change the expression of peroxisome proliferator-activated receptor (PPAR)alpha, PPARgamma, liver X receptor alpha (LXRalpha), farnesoid X receptor (FXR), ABCG5, ABCG8, and 7alpha-hydroxylase (CYP7A1) which are directly involved in the cholesterol saturation index in bile. METHODS: Human Hep3B cells were cultured on dishes. MTT assays were performed to determine the appropriate concentrations of reagents to be used. The protein expression of PPARalpha and PPARgamma was measured by Western blotting analysis, and the mRNA expression of LXRalpha, FXR, ABCG5, ABCG8 and CYP7A1 was estimated by RT-PCR. RESULTS: In cultured Hep3B cells, pravastatin activated PPARalpha and PPARgamma protein expression, induced stronger expression of PPARgamma than that of PPARalpha, increased LXRalpha mRNA expression, activated ABCG5 and ABCG8 mRNA expression mediated by FXR as well as LXRalpha, enhanced FXR mRNA expression, and increased CYP7A1 mRNA expression mediated by the PPARgamma and LXRalpha pathways, together or independently. CONCLUSION: Our data suggested that pravastatin prevents cholesterol gallstone diseases via the increase of FXR, LXRalpha and CYP7A1 in human hepatocytes.

Statin induces apoptosis of human colon cancer cells and downregulation of insulin-like growth factor 1 receptor via proapoptotic ERK activation.

Insulin-like growth factor 1 (IGF-1) and IGF-1 receptor (IGF-1R) signaling plays an important role in tumor progression in patients with certain gastrointestinal tract cancers. In addition to lowering cholesterol in serum, statins have pleiotropic effects, including anti-oxidative, anti-inflammatory or anti-neoplastic effects. Therefore, the present study investigated whether statins could induce the apoptosis of colon cancer cells and regulate the expression of IGF-1R and its associated signaling pathways in the present study. It was demonstrated that simvastatin and pravastatin suppressed cell proliferation and induced cell death in human HT-29 cells, but simvastatin was more potent than pravastatin. Simvastatin induced apoptosis in a concentration-dependent manner. In addition, simvastatin suppressed the expression of IGF-1R and inhibited the activity of phosphorylated-extracellular signal-regulated kinase (ERK)1/2 and phosphorylated-Akt activated by IGF-1. Simvastatin and IGF-1 each stimulated the activity of phosphorylated ERK1/2. However, simvastatin inhibited cell proliferation and IGF-1 stimulated cell proliferation. Mevalonic acid and PD98059 reversed the ERK activation and apoptosis induced by treatment with simvastatin. It was concluded that simvastatin induces the apoptosis of human colon cancer cells and inhibits IGF-1-induced ERK and Akt expression via the downregulation of IGF-1R expression and proapoptotic ERK activation. Simvastatin may be beneficial for the treatment of colon cancer. The present study suggested that statin may possess therapeutic potential for the treatment of colon cancer.

Synergistic Effects of Simvastatin and Irinotecan against Colon Cancer Cells with or without Irinotecan Resistance.

Aims. We here investigated whether the combination of simvastatin and irinotecan could induce the synergistic effect on colon cancer cells with or without resistance to irinotecan. Methods. We investigated cell proliferation assay and assessed cell death detection ELISA and caspase-3 activity assay of various concentrations of simvastatin and irinotecan to evaluate the efficacy of drug combination on colon cancer cells with or without irinotecan resistance. Results. The IC50 values of simvastatin alone and irinotecan alone were 115.4 ± 0.14 µM (r = 0.98) and 62.5 ± 0.18 µM (r = 0.98) in HT-29 cells without resistance to irinotecan. The IC50 values of these two drugs were 221.9 ± 0.22 µM (r = 0.98) and 195.9 ± 0.16 µM (r = 0.99), respectively, in HT-29 cell with resistance to irinotecan. The results of combinations of the various concentrations of two drugs showed that combined treatment with irinotecan and simvastatin more efficiently suppressed cell proliferation of HT-29 cells even with resistance to irinotecan as well as without resistance. Furthermore, the combination of simvastatin and irinotecan at 2 : 1 molar ratio showed the best synergistic interaction. Conclusion. Simvastatin could act synergistically with irinotecan to overcome irinotecan resistance of colon cancer.

The effect of PPARalpha and PPARgamma ligands on inflammation and ABCA1 expression in cultured gallbladder epithelial cells.

The preservation of gallbladder function by control of inflammation and elimination of cholesterol accumulation in gallbladder epithelial cells (GBEC) could contribute to the prevention of gallstone formation and cholecystitis. Peroxisome proliferator-activated receptors (PPARs) modulate inflammation and lipid metabolism in various cells and GBEC efflux of excessive amounts of absorbed cholesterol through the ATP-binding cassette transporter A1 (ABCA1)-mediated pathway. The aim of this study was to determine whether ligands of PPARalpha and PPARgamma modulate inflammation and have an effect on ABCA1 expression in GBEC. Canine GBEC were cultured on dishes coated with collagen matrix. We performed Western blot analysis for the expression of specific protein and/or RT-PCR for the expression of specific mRNA. PPARalpha and PPARgamma expression was observed and increased in GBEC treated with WY-14643 (PPARalpha ligand), troglitazone (PPARgamma ligand), and lipopolysaccharide (LPS) compared to the no-treatment control and PPARalpha( antagonist (GW-9662) treatment group. WY-14643, troglitazone, and LPS also induced an increase in the expression of ABCA1 protein and mRNA in cultured GBEC. LPS-induced TNFalpha mRNA expression was suppressed by pretreatment with WY-14643 and troglitazone preceding LPS treatment in GBEC. PPAR ligands, especially PPARgamma, may preserve gallbladder function by suppression of inflammatory reaction and prevention of cholesterol accumulation in GBEC, contributing to the prevention of gallstone formation and progression to cholecystitis.