Modulatory effects of α- linolenic acid on generation of reactive oxygen species in elaidic acid enriched peritoneal macrophages in rats.

Fatty acids are known to influence the ability of macrophages to generate reactive oxygen species (ROS). However the effect of elaidic acid (EA, 18:1 trans fatty acid) on ROS generation is not well studied. Rat peritoneal macrophages were enriched with elaidic acid by incubating the cells with 80 µM EA. The macrophages containing EA generated higher amounts of superoxide anion (O2·-), hydrogen peroxide (H2O2) and nitric oxide (NO˙) by 54, 123 and 237%, respectively as compared to control cells which did not contain EA. To study the competition of other C18 fatty acids with EA macrophages were incubated with EA along with stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2) and α- linolenic acid (ALA, 18:3). ALA significantly reduced the incorporation of EA into macrophage lipids. This also significantly reduced the generation of O2· -, H2O2, NO˙ by macrophages. Studies were also conducted by feeding rats with diet containing partially hydrogenated vegetable fat (PHVF) as a source for EA and linseed oil (LSO) as a source for ALA. The rats were fed AIN-93 diet containing PHVF with 17% EA and incremental amounts of linseed oil for 10 weeks. The peritoneal macrophages from rats fed partially hydrogenated vegetable fat generated higher levels of O2·-, H2O2, NO˙ by 46, 161 and 76% respectively, when compared to rats fed control diets containing ground nut oil. Macrophages from rats fed PHVF with incremental amounts of LSO produced significantly lower levels ROS in a dose dependent manner. Thus ALA reduces the higher levels of ROS generated by macrophages containing EA.

Lipotoxicidade na leptospirose humana: aspectos prognósticos e potencial efeito benéfico da administração de albumina / Lipotoxicity in human leptospirosis: prognostics aspects and potential beneficial effect of albumin administration

A leptospirose humana é uma doença infecciosa aguda de amplo espectro clínico e que cursa com alterações metabólicas e dislipidêmicas envolvendo colesterol total e frações, triglicerídeos e ácidos graxos não esterificados (AGNEs). Dentre os mecanismos celulares envolvidos na sua fisiopatologia encontram-se a inibição da enzima Na, K ATPase pela endotoxina GLP e a lipotoxicidade, ambos agravados pela redução dos níveis circulantes da albumina, molécula que exerce um papel fundamental na adsorção de moléculas lipídicas. Neste estudo observacional, determinamos as concentrações séricas de bilirrubina, creatinina e albumina e, pela técnica de cromatografia líquida de alta performance, a concentração sérica dos AGNEs de cadeia longa (C16: C18) de 27 pacientes com síndrome de Weil durante o período de internação hospitalar, dos quais cinco vieram a falecer. Verificamos correlações significantes (p<0,05) ao longo da internação hospitalar, nas concentrações séricas de marcadores bioquímicos de gravidade da doença (bilirrubina, creatinina e albumina), AGNEs, ácido oléico e ácido linoléico, e relação molar ácido oléico/albumina, com r (Pearson) de -0,7981, -0,7699, 0,9014, -0,8795 -0,9816, -0,9694, -0,9821, respectivamente. A relação molar ácido oléico/albumina e ácido oléico+linoléico/albumina foi significantemente mais elevada nos pacientes que faleceram (p<0,001), retornando aos valores semelhantes aos do grupo controle nos pacientes que evoluíram para a cura. Na análise por Curva Roc, a relação molar ácido oléico/albumina se mostrou um bom teste preditivo, com valor de corte 0,705 associado com maior especificidade e sensibilidade prognóstica. Nossos resultados sugerem que a utilização parenteral da albumina humana em pacientes com leptospirose pode ser uma potente ferramenta terapêutica nos casos mais graves ao interferir positivamente no resgate do equilíbrio bioquímico das relações molares ácido oléico/algumina e ácido oléico+linoléico/algumina.

Human leptospirosis is an acute infectious disease with a broad clinical spectrum. It courses with metabolic and dyslipidemic alterations, involving total cholesterol and fractions, triglycerides and nonesterified fatty acids (NEFAs). The cellular mechanisms involved in its pathogenesis include the inhibition of the enzyme sodium-potassium adenosine triphosphatase and lipotoxicity. Both mechanisms are aggravated by the reduction of serum levels of albumin, a molecule that plays a fundamental role in the absorption of lipid molecules. In this observational study, we determined the serum concentrations of bilirubin, creatinine and albumin, and, by High Performance Liquid Chromatography, the serum concentrations of long chain NEFAs (C16: C18) during the period of hospitalization of 27 patients with Weil's syndrome, five of whom progressed to death. Significant correlations were found between the length of hospitalization and serum concentrations of biochemical markers of severity (bilirubin, creatinine, albumin), NEFAs, oleic acid and linoleic acid, and the oleic acid: albumin molar ratio, with r (Pearson) of de -0,7981, -0,7699, 0,09014, -0,8795 -0,9816, -0,9694, -09821 respectively. The oleic acid: albumin molar ratio and oleic-plus-linoleic acid: albumin molar ratio were significantly higher in the patients who progressed to death, whereas in the cured patients this ratio decreased to levels that were similar to those found in the control group. Roc Curve analysis for the acid oleic: albumin molar ratio proved a good predictive test, with value of cutting 0.705 associated with greater specificity and prognostic sensitivity. Our results suggest that parenteral administration of human albumine may interfere positively in the rescue of biochemical balance of oleic acid: albumin molar ratio and oleic-plus-linoleic acid: albumin molar ratio and be a therapeutic tool for severe cases of leptospirosis.

Protection of INS-1 cells from free fatty acid-induced apoptosis by inhibiting the glycogen synthase kinase-3 / 华中科技大学学报（医学）（英德文版）

To examine the role of glycogen synthase kinase 3 (GSK-3) in the apoptosis of pancreatic beta-cells to better understand the pathogenesis and to find new approach to the treatment of type 2 diabetes, apoptosis was induced by oleic acid (OA) in INS-1 cells and the activity of GSK-3 was inhibited by LiCl. The PI staining and flow cytometry were employed for the evaluation of apoptosis. The phosphorylation level of GSK-3 was detected by Western blotting. The results showed that OA at 0.4 mmol/L could cause conspicuous apoptosis of INS-1 cells and the activity of GSK-3 was significantly increased. After the treatment with 24 mmol/L of LiCl, a inhibitor of GSK-3, the OA-induced apoptosis of INS-1 cells was lessened and the phosphorylation of GSK-3 was increased remarkably. It is concluded that GSK-3 activation plays an important role in OA-induced apoptosis in pancreatic beta-cells and inhibition of the GSK-3 activity can effectively protect INS-1 cells from the OA-induced apoptosis. Our study provides a new experimental basis and target for the clinical treatment of type-2 diabetes.

Dexamethasone enhances phospholipase D activity in M-1 cells

Phospholipase D (PLD) is an enzyme involved in signal transduction and widely distributed in mammalian cells. The signal transduction pathways and role for phospholipid metabolism during hormonal response in cortical collecting duct remain partly undefined. It has been reported that dexamethasone increases transepithelial transport in M-1 cells that are derived from the mouse cortical collecting duct. We investigated the expression and activity of PLD in M-1 cells. Basal PLD activity of M-1 cells cultured in the presence of dexamethasone (5 microM) was higher than in the absence of dexamethasone. Dexamethasone and ATP activated PLD in M-1 cells but phorbol ester did not stimulate PLD activity. Vasopressin, bradykinin, dibutyryl cyclic AMP, and ionomycin were ineffective in activating PLD of the cells. The PLD2 isotype was detected by immunoprecipitation but PLD1 was not detected in M-1 cells. Addition of GTPgammaS and ADP-ribosylation factor or phosphatidylinositiol 4,5-bisphosphate to digitonin-permeabilized cells did not augment PLD activity. In intact cells PLD activity was increased by sodium oleate but there was no significant change between dexamethasone treated- and untreated cells by oleate. These results suggest that at least two types of PLD are present in M-1 cells and PLD plays a role in the corticosteroid-mediated response of cortical collecting duct cells.