Fenofibrate prevents orotic acid--induced hepatic steatosis in rats

The experiments performed in this report were designed to investigate the mechanisms involved in the metabolic alterations associated with orotic acid-induced hepatic steatosis and the effect of fenofibrate, a stimulant of peroxisome proliferators-activated receptor alpha (PPARalpha), on these alterations. Male Wistar rats were divided into three experimental groups: 1) fed a balanced diet (C); 2) fed a balanced diet supplemented with 1% orotic acid (OA); 3) fed OA diet containing 100 mg.kg(-1) bw.day(-1) fenofibrate (OA+F), for 9 days. Administration of OA to rats induced significant increase in the hepatic total lipids content, marked microvesicular steatosis and decrease in plasma lipids concentrations compared to control group. Fenofibrate treatment prevented fatty liver induction, caused an additional reduction on plasma lipids concentrations and caused a 40% decrease in the lipogenic rate in adipose tissue. The results also showed a 40% increase in lipoprotein lipase (LPL) activity in adipose tissue from OA treated group and fenofibrate administration induced a 50% decrease in LPL activity. The liver mRNA expression of PPARalpha and ACO (acyl CoA oxidase) were 85% and 68% decreased in OA group when compared to control, respectively. Fenofibrate treatment increased the PPARalpha and ACO expressions whereas the CPT-1 (carnitine palmitoyl transferase-1) expression was not altered. Our results have shown that fenofibrate treatment decreases the hepatic lipid content induced by OA which is mediated by an important increase in fatty acid oxidation consequent to an increase in hepatic mRNA expression of PPARalpha and ACO.     

Inhibition of crotoxin binding to synaptosomes by a receptor-like protein from Crotalus durissus terrificus (the South American rattlesnake)

Crotoxin (Ctx) is a potent neurotoxin of the venom of Crotalus durissus terrificus (the South American rattlesnake). Ctx is a heterodimer composed of CB, a toxic PLA₂ subunit, and CA, a non-toxic and non-enzymatic subunit, that potentiates the neurotoxicity of CB in vivo. The deleterious action of Ctx upon C. d. terrificus snakes themselves is known to be prevented by a PLA₂ inhibitor (CNF) present in their blood serum. CNF acts by replacing CA in Ctx, thus forming a new stable complex CNF-CB. This complex no longer interacts with the target receptor (TR) to deliver CB to cause its lethal effect. Furthermore, CNF-CB seems to be reminiscent of the interaction Ctx-TR at the pre-synaptic site. In the present work, the binding competition between rat brain synaptosomes (TR) and CNF for Ctx was investigated. Radiolabeled Ctx, made of CA and one isoform of CB (CA-¹²⁵ICB₂), was used as ligand. The competition by unlabeled Ctx was taken as a reference. The potency of CNF as a competitor was evaluated under different incubation conditions with varying time scale addition of reagents (CA-¹²⁵ICB₂, synaptosomes and CA-CB₂ or CNF). CNF was able to inhibit the binding of the toxin to synaptosomes as well as to partially displace the toxin already bound to its membrane target. The mechanisms of competition involved were discussed and a previous schematic model of interactions between Ctx, TR and CNF was updated.     

Improvement of the energy supply and contractile function in normal and ischemic rat hearts by dietary orotic acid

AimsAs cardiac performance is closely related to its energy supply, our study investigated the effect of the orotic acid cardioprotective agent on the pathways of energy supply, in both conditions of normal flow and ischemia.Main methodsMale Wistar rats were fed during nine days with a balanced diet only or supplemented with 1% orotic acid.Key findingsDietary administration of orotic acid increased the cardiac utilization of fatty acids, activity of the lipoprotein lipase, expression of the gene of peroxisome proliferator-activated receptor α and its target enzymes. In addition, orotic acid increased the myocardial uptake and incorporation of glucose, glycogen content and level of GLUT4, concentration of glycolytic metabolites and lactate production in both experimental conditions, baseline and after regional ischemia.SignificanceThus, in orotic acid hearts there was a simultaneous stimulus of fatty acid oxidation and glycolytic pathway, reflected in increased energetic content even in pre-ischemia. The analysis of the cardiac contractility index showed a positive inotropic effect of orotic acid due, at least in part, to the increased availability of energy. The result allows us to suggest that the metabolic changes induced by orotic acid result in appreciable alterations on myocardial contractile function.     

Pancreaticoduodenectomy Combined with Vascular Resection and Reconstruction for Patients with Locally Advanced Pancreatic Cancer: A Multicenter,Retrospective Analysis

Objective

The aim of this study was to present the therapeutic outcome of patients with locally advanced pancreatic cancer treated with pancreatoduodenectomy combined with vascular resection and reconstruction in addition to highlighting the mortality/morbidity and main prognostic factors associated with this treatment.

Materials and Methods

We retrospectively analyzed the clinical and pathological data of a total of 566 pancreatic cancer patients who were treated with PD from five teaching hospitals during the period of December 2006–December 2011. This study included 119 (21.0%) patients treated with PD combined with vascular resection and reconstruction. We performed a detailed statistical analysis of various factors, including postoperative complications, operative mortality, survival rate, operative time, pathological type, and lymph node metastasis.

Results

The median survival time of the 119 cases that received PD combined with vascular resection was 13.3 months, and the 1-, 2-, and 3-year survival rates were 30.3%, 14.1%, and 8.1%, respectively. The postoperative complication incidence was 23.5%, and the mortality rate was 6.7%. For the combined vascular resection group, complications occurred in 28 cases (23.5%). For the group without vascular resection, complications occurred in 37 cases (8.2%). There was significant difference between the two groups (p = 0.001). The degree of tumor differentiation and the occurrence of complications after surgery were independent prognostic factors that determined the patients’ long-term survival.

Conclusions

Compared with PD without vascular resection, PD combined with vascular resection and reconstruction increased the incidence of postoperative complications. However, PD combined with vascular resection and reconstruction could achieve the complete removal of tumors without significantly increasing the mortality rate, and the median survival time was higher than that of patients who underwent palliative treatment. In addition, the two independent factors affecting the postoperative survival time were the degree of tumor differentiation and the presence or absence of postoperative complications.     

Inhibition of crotoxin binding to synaptosomes by a receptor-like protein from Crotalus durissus terrificus (the South American rattlesnake)

Crotoxin (Ctx) is a potent neurotoxin of the venom of Crotalus durissus terrificus (the South American rattlesnake). Ctx is a heterodimer composed of CB, a toxic PLA(2) subunit, and CA, a non-toxic and non-enzymatic subunit, that potentiates the neurotoxicity of CB in vivo. The deleterious action of Ctx upon C. d. terrificus snakes themselves is known to be prevented by a PLA(2) inhibitor (CNF) present in their blood serum. CNF acts by replacing CA in Ctx, thus forming a new stable complex CNF-CB. This complex no longer interacts with the target receptor (TR) to deliver CB to cause its lethal effect. Furthermore, CNF-CB seems to be reminiscent of the interaction Ctx-TR at the pre-synaptic site. In the present work, the binding competition between rat brain synaptosomes (TR) and CNF for Ctx was investigated. Radiolabeled Ctx, made of CA and one isoform of CB (CA-(125)ICB(2)), was used as ligand. The competition by unlabeled Ctx was taken as a reference. The potency of CNF as a competitor was evaluated under different incubation conditions with varying time scale addition of reagents (CA-(125)ICB(2), synaptosomes and CA-CB(2) or CNF). CNF was able to inhibit the binding of the toxin to synaptosomes as well as to partially displace the toxin already bound to its membrane target. The mechanisms of competition involved were discussed and a previous schematic model of interactions between Ctx, TR and CNF was updated.