糖尿病大鼠肾皮质PDGF、LOX-1、TGF-β的基因表达探讨

目的：观察血小板衍化生长因子（PDGF）、氧化低密度脂蛋白内皮受体-1（LOX-1）、转移生长因子（TGF-β）因子在糖尿病肾病的发生、发展中的作用。方法：用反转录半定量聚合酶链反应（RT-PCR）法测定18只STZ模型鼠（DN组）及6只对照K（NC组）的PEGF、LOX-1、TGF-β等基因表达以及mRNA含量的变化。结果：DN组大鼠肾皮质PDGFmRNA、LOX-1mRNA、TGF-βmRNA基因表达较NC组明显增高；（P〈0．01）。结论：在糖尿病后期，PEGF、LOX-1、TGF-β生成增加，参与并加剧了糖尿病肾脏的病变。     

Complementary Roles for Scavenger Receptor A and CD36 of Human Monocyte–derived Macrophages in Adhesion to Surfaces Coated with Oxidized Low-Density Lipoproteins and in Secretion of H2O2

Oxidized low-density lipoprotein (oxLDL) is considered one of the principal effectors of atherogenesis. To explore mechanisms by which oxLDL affects human mononuclear phagocytes, we incubated these cells in medium containing oxLDL, acetylated LDL (acLDL), or native LDL, or on surfaces coated with these native and modified lipoproteins. The presence of soluble oxLDL, acLDL, or native LDL in the medium did not stimulate H₂O₂ secretion by macrophages. In contrast, macrophages adherent to surfaces coated with oxLDL secreted three- to fourfold more H₂O₂ than macrophages adherent to surfaces coated with acLDL or native LDL. Freshly isolated blood monocytes secreted little H₂O₂ regardless of the substrate on which they were plated. H₂O₂ secretion was maximal in cells maintained for 4–6 d in culture before plating on oxLDL-coated surfaces. Fucoidan, a known ligand of class A macrophage scavenger receptors (MSR-A), significantly reduced macrophage adhesion to surfaces coated with oxLDL or acLDL. Monoclonal antibody SMO, which blocks oxLDL binding to CD36, did not inhibit adhesion of macrophages to oxLDL-coated surfaces but markedly reduced H₂O₂ secretion by these cells. These studies show that MSR-A is primarily responsible for adhesion of macrophages to oxLDL-coated surfaces, that CD36 signals H₂O₂ secretion by macrophages adherent to these surfaces, and that substrate-bound, but not soluble, oxLDL stimulates H₂O₂ secretion by macrophages.     

The relationship of TFPI, Lp(a), and oxidized LDL antibody levels in patients with coronary artery disease

OBJECTIVES: The aim of the present study was to determine and correlate tissue factor pathway inhibitor (TFPI), lipoprotein (a) (Lp(a)), oxidized low-density lipoprotein (LDL) antibody (oLAB), and thiobarbituric acid reactive substances (TBARS; as a marker of lipid peroxidation) levels in patients with coronary artery disease (CAD) and in a control group. DESIGN AND METHODS: Peripheral blood samples from patients with coronary heart disease were provided by the Department of Cardiology. Serum oLAB, Lp(a), plasma total TFPI, and plasma-free TFPI levels were determined by ELISA. Serum TBARS levels were determined by a spectrophotometric method using thiobarbituric acid. RESULTS: The CAD and the control group were matched for age and sex. Serum Lp(a), oLAB, and plasma total TFPI levels in patients with coronary heart disease were found to be significantly higher than in the control group (P < 0.001). But there was no difference in plasma-free TFPI levels between patients with CAD and the control group (P > 0.05). In patients with single (P < 0.05), double, and triple vessel (P < 0.01) disease, the mean serum Lp(a) levels were significantly higher than in the control group. On the other hand, in patients with single vessel disease (P < 0.05), double vessel disease (P < 0.05), and triple vessel disease (P < 0.001), plasma total TFPI levels were found to be significantly higher than in the control group. We also found a significant positive correlation (r = 0.28, P < 0.05) between serum Lp(a) and plasma total TFPI levels in CAD. In the patient group, TBARS, total cholesterol, triglyceride (TRG), and LDL cholesterol levels were found to be significantly higher than those in the control group. In addition, high-density lipoprotein (HDL) cholesterol levels were found to be significantly lower than the control group. CONCLUSIONS: These results suggest that elevated plasma levels of total TFPI, Lp(a), and oLAB may be useful diagnostic and monitoring markers in patients with CAD.     

Influence of a thiazole derivative on ethanol and thermally oxidized sunflower oil-induced oxidative stress

The present work describes the protective influence of the dendrodoine analogue (DA) [4-amino-5-benzoyl-2-(4-methoxy phenylamino) thiazole] on thermally oxidized sunflower oil and ethanol-induced oxidative stress. Ethanol was fed to animals at a level of 20% [(7.9 g/kg body weight (bw)] and thermally oxidized sunflower oil at a level of 15% (15 mL/100 g feed). Hepatotoxicity was assessed by measuring the activity of plasma aspartate transaminase (AST), alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT), which were elevated in thermally oxidized oil, and ethanol fed rats when compared with normal control rats. Tissue damage was associated with increased lipid peroxidation and disruption in the antioxidant defence mechanism in thermally oxidized oil- and ethanol-fed groups when compared with normal control group. The activity of liver marker enzymes (AST, ALP and GGT) and the level of lipid peroxidation decreased when DA was administered along with ethanol and thermally oxidized oil. The antioxidant status was near normal in DA-administered groups. Thus we propose that DA exerts antioxidant properties by modulating the activity of hepatic marker enzymes, level of lipid peroxidation and antioxidant status.     

Pathogenic molecular mechanisms in an animal model of fulminant hepatic failure: rabbit hemorrhagic viral disease

In this study we sought to determine whether molecular mechanisms involved in the pathogenesis of fulminant hepatic failure are present in rabbits experimentally infected with rabbit hemorrhagic disease virus (RHDV). The activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, as well as bilirubin concentration, were found to be significantly increased 36 hours after infection. Infected animals also demonstrated significant decreases in factor VII activity, in the Fischer index, and in the deterioration of prothrombin time. The concentration of reduced glutathione was significantly decreased 36 hours after infection, and we noted a marked increase in the ratio of oxidized to reduced glutathione. Infected animals showed progressive decreases in liver activity of the antioxidant enzyme superoxide dismutase. Expression of hepatocyte growth factor and c-met was found to be progressively reduced from 24 hours after infection, during which time we detected no modification in messenger RNA (mRNA) levels of transforming growth factor (TGF)-alpha. TFG-beta 1 was overexpressed 24 and 36 hours after infection, and 36 hours after infection we detected a significant increase in TNF-alpha mRNA levels. Experimental RHDV infection also induced marked activation of nuclear factor-kappaB and a significant increase in inducible nitric oxide synthase mRNA levels from 24 hours after infection. Data obtained from this animal model support its usefulness in the investigation of potential novel therapeutical modalities aimed at neutralizing reactive oxygen species and hepatocyte growth inhibitors or enhancing hepatocyte responsiveness to mitogens.     

Oxidized low-density lipoprotein-induced expression of ABCA1 in blood monocytes precedes coronary atherosclerosis and is associated with plaque complexity in hypercholesterolemic pigs

BACKGROUND: Elevated oxidized low-density lipoprotein (oxLDL) is associated with atherosclerosis and high cardiovascular risk. Previously, we identified 18 genes in coronary plaque macrophages of hypercholesterolemic pigs that correlated with plaque oxLDL. OBJECTIVE: To determine which of these genes were differentially expressed in blood monocytes and correlated with blood and plaque oxLDL and with plaque complexity. METHODS: RNA expression in monocytes of 27 hypercholesterolemic and 12 control pigs was analyzed with quantitative real-time polymerase chain reaction. RESULTS: Five of 12 genes with detectable expression in monocytes were overexpressed (at P < 0.01 level) in blood monocytes of hypercholesterolemic pigs: ABCA1, SCD, IRF1, SDC2, and TLR2. ABCA1 RNA expression in blood monocytes correlated with blood oxLDL, and its RNA and protein expression was increased prior to atherosclerotic plaque formation. Higher expression of ABCA1 in monocytes was associated with higher plaque complexity and higher plaque oxLDL. Immunostaining of coronary plaques showed the association of ABCA1 with macrophages, lipids, and oxLDL; ABCA1 protein correlated with plaque oxLDL (R(2) = 0.66; P < 0.0001). In THP-1 monocytes, oxLDL induced ABCA1 expression. OxLDL-induced foam cell generation in THP-1 and human monocyte-derived macrophages was associated with a further increase of ABCA1 expression. CONCLUSIONS: The increase of ABCA1 in monocytes in association with blood oxLDL prior to atherosclerotic lesion formation and the association of higher ABCA1 with higher plaque complexity suggests that ABCA1 is an early biomarker of atherosclerosis. Studies in humans are warranted.     

KR 31372, a benzopyran derivative, inhibits oxidized LDL-stimulated proliferation and migration of vascular smooth muscle cells

KR 31372 is a benzopyran derivative. Both [3H]thymidine incorporation and migrations (chemotactic and wound-edge) of cultured smooth muscle cells (SMCs) were greatly stimulated by oxidized low-density lipoprotein (LDL). These effects were significantly suppressed by KR 31372 (10(7) - 10(6) M) and PDGF-BB antibody (10(8) - 10(6) M). Preincubation with KR 31372 led to a decrease in the synthesis of PDGF-BB-like immunoreactivity (PDGF-BB-LI) that had been stimulated by oxidized LDL. Otherwise, KR 31372 and probucol strongly inhibited the production of thiobarbituric acid reactive substances (TBARS) caused by the incubation of LDL with Cu2+ ion, and significantly reduced the intracellular oxidative stress when stimulated with H,O2. Taken together, it is suggested that KR 31372 may inhibit the oxidized LDL-stimulated syntheses of DNA and PDGF-BB, and migration of the SMCs, in part, via the antioxidant activity.     

低密度、氧化低密度脂蛋白对内皮细胞分泌内皮素的影响

目的 观察低密度脂蛋白（LDL）、氧化低密度脂蛋白（ox-LDL）对内皮细胞分泌内皮素（ET）的影响，以及后者在体外是否对前者具有氧化修饰作用.方法 采用不同浓度的LDL、ox-LDL及LDL＋ox-LDL与脐静脉内皮细胞株ECV-304进行孵育，24 h后分别收集细胞和上清液，采用放免分析法测定ET含量.结果 LDL、ox-LDL均能促进内皮细胞合成、分泌ET，但ox-LDL的作用更显著，而LDL＋ox-LDL组上清ET浓度大于两者单独作用之和.结论 LDL、ox-LDL均能促进内皮细胞合成、分泌ET，但后者的作用更为明显，且在体外对LDL具有氧化修饰作用。     

氟伐他汀对冠心病患者PAPP-A和ox-LDL水平的影响

目的观察氟伐他汀治疗对冠心病患者妊娠相关血浆蛋白-A（PAPP-A）和氧化型低密度脂蛋白（ox-LDL）水平的影响。方法选择冠心病组患者75例,包括急性心肌梗死（AMI）患者32例,不稳定型心绞痛（UAP）患者22例和稳定型心绞痛（SAP）患者21例。正常对照组60例。采用双抗体夹心酶联免疫吸附试验检测冠心病患者PAPP-A和ox-LDL水平。结果PAPP-A在急性冠脉综合征组（ACS,包括AMI、UAP）浓度较SAP及正常对照组均明显偏高（P<0.05）;ox-LDL在冠心病组中的浓度较正常对照组高（P<0.05）,且在AMI、UAP、SAP各组组间比较均有显著性差异（P<0.05）;氟伐他汀治疗后冠心病患者PAPP-A和ox-LDL浓度均显著下降（P<0.01）;PAPP-A与ox-LDL水平呈正相关（P<0.01）。结论氟伐他汀治疗后冠心病患者PAPP-A和ox-LDL浓度降低,氟伐他汀可能通过抑制炎症反应,减少氧化应激来发挥心血管的保护作用。