Clotrimazole protects the liver against normothermic ischemia-reperfusion injury in rats.

OBJECTIVE: To investigate the possible antiapoptotic prosurvival role of the pregnane X receptor (PXR) in hepatic ischemia-reperfusion injury in rats using clotrimazole (CTZ), a strong PXR transactivator. MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into 3 groups of 6 each: sham-treated, control, and CTZ-treated animals. Control and CTZ-treated animals were subjected to 30 minutes of normothermic ischemia of the whole liver followed by 6 hours of reperfusion. The animals were then killed, and the liver was excised and blood samples collected. RESULTS: Clotrimazole induced a significant increase in expression of the CYP3A gene, indicating PXR transactivation, whereas expression of the antiapoptotic Bcl-xL gene was not increased. Serum concentrations of aspartate aminotransaminase and alanine aminotransaminase were lower in CTZ-treated animals than in control animals (difference not significant). Levels of poly(adenosine diphosphate-ribose) polymerase, a caspase-3 substrate, remained significantly higher in the CTZ-treated group compared with controls (P < .05). Clotrimazole increased the expression of phospho-p 44/42 extracellular signal-regulated kinase 1,2 (P < .05). The gene expression of the heat shock proteins 27, 70 and 90 was significantly lower in CTZ-treated animals than in controls (P < .05). CONCLUSION: Clotrimazole-mediated PXR transactivation protects the liver against ischemia-reperfusion apoptosis in rats. Phospho-p 44/42 extracellular signal-regulated kinase 1,2 is activated, whereas gene expression of heat shock proteins 27, 70, and 90 is downregulated by induction of PXR.

Bacterial translocation in adult small bowel transplantation.

The application of intestinal transplantation is limited by the high rate of infectious complications that can occur; the migration of enteric microorganisms to extraintestinal sites (bacterial translocation) has been suggested to be responsible for this event. We reviewed 95 intestinal biopsies performed on 28 transplanted patients to identify histologic features predictive of isolation of enteric microorganisms in extraintestinal sites within the first month after transplantation. At least 1 isolation of enteric microorganisms in the peritoneal cavity and/or in blood samples was obtained in 13 patients (46.4%); this event led to higher 1-year mortality (38.5% vs. 6.7%; P = .041). Of the 95 biopsies, 38 were followed by positive cultures (40.0%), showing higher degrees of mucosal vascular alterations (Ruiz grade) and ischemia/reperfusion injuries (Park/Chiu grade) compared with the negative cases (P < .05). We also observed an higher prevalence of positive cultures in relation to acute cellular rejection episodes (P = .091). Neither clinical or surgical factors nor immunosuppressive therapy were observed to be significantly related to positive cultures. Histologic alterations of the small bowel allograft are related to isolation of enteric microorganisms in extraintestinal sites. The degree of these histologic features can identify patients at high risk of potentially life-threatening infectious complications and death.

Elevated E-cadherin and alpha/beta-catenin expression after androgen deprivation therapy in prostate adenocarcinoma.

The histological patterns of anti-androgen-treated prostate adenocarcinoma mimic high grade tumors classified according to the widely used Gleason scoring system. However, the biological characteristics of anti-androgen treated carcinoma are largely unknown. E-cadherin, alpha-catenin, and beta-catenin adhesion molecules are down-regulated in pharmacologically untreated high grade prostate carcinoma. In this study, we used immunohistochemical techniques to investigate their expression in twenty acinar adenocarcinomas after anti-androgen therapy in prostatectomy specimens. After adrogen ablation therapy, expression of all these adhesion molecules was higher than that of pretreatment biopsies of the same patient group and high grade matched untreated controls. These results emphasize the inaccuracy of the Gleason score for anti-androgen-treated prostate adenocarcinoma and the more differentiated phenotype of prostate adenocarcinoma after anti-hormonal therapy.

Spontaneous apoptosis in primary cultures of human and rat hepatocytes: molecular mechanisms and regulation by dexamethasone.

To elucidate the biochemical pathways leading to spontaneous apoptosis in primary cultures of human and rat hepatocytes, we examined the activation of the caspase cascade, the expression of Bcl-2-related-proteins and heat shock proteins. Comparisons were made before and after dexamethasone (DEX) treatment. We show that DEX inhibited spontaneous apoptosis in a dose-dependent manner. DEX increases the expression of anti-apoptotic Bcl-2 and Bcl-x(L) proteins, decreases the expression of pro-apoptotic Bax and inhibits Bad translocation thereby preventing the release of cytochrome c, the activation of caspases, and cell death. Although, the expression of Hsp27 and Hsp70 proteins remained unchanged, the oncogenic protein c-Myc is upregulated upon DEX-treatment. These results indicate that DEX mediates its survival effect against spontaneous apoptosis by acting upstream of the mitochondrial changes. Thus, the mitochondrial apoptotic pathway plays a major role in regulating spontaneous apoptosis in these cells. Blocking this pathway therefore may assist with organ preservation for transplant, drug screening, and other purposes.