The Relationship Between Lipid Peroxidation and LDL Desialylation in Experimental Atherosclerosis.

ABSTRACT High serum total cholesterol concentration has been strongly connected with atherosclerosis in numerous studies. Being the main carrier of cholesterol in blood, low-density lipoprotein (LDL) is also the principal lipoprotein causing atherosclerosis. Sialic acids are a family of amino sugars that are commonly found as terminal oligosaccharide residues on glycoproteins and are sialylated on their apolipoprotein and glycolipid constituents. In several studies, it was demonstrated that LDL has a 2.5- to 5-fold lower content of sialic acid in patients with coronary artery disease compared with healthy subjects. The role of oxidatively modified LDL in the pathogenesis has been well documented. These studies have focused on modifications in the lipid and protein parts of LDL. But recently, desialylated LDL and its relation with the oxidation mechanisms have received attention in the pathogenesis of atherosclerosis and coronary artery disease (CAD). From these points, we have performed atheroma plaques in an experimental atherosclerosis model with rabbits and examined the LDL and plasma sialic acid and thiobarbituric acid reactive substance (TBARS) levels in the same model. We also have determined serum sialidase enzyme activities relevant with these parameters. LDL sialic acid levels were significantly decreased in the progression of the atherosclerosis (by the 30th, 60th, and 90th days). LDL and plasma TBARS levels and plasma sialidase enzyme activities were significantly elevated by the same time periods. In conclusion, serum sialidase enzyme may play an important role in the desialylation mechanism, and reactive oxygen substance (ROS) may affect this reaction.

Relation between serum Insulin-like growth factor-I and insulin-like growth factor-binding protein-3 levels, clinical status and growth parameters in prepubertal cystic fibrosis patients.

BACKGROUND: This study aims to determine the relation between anabolic hormones, Insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3), growth parameters, and clinical status in prepubertal cystic fibrosis (CF) patients. This prospective study comprises age/sex-matched control subjects and was set in a tertiary care teaching hospital. METHODS: Serum concentrations of IGF-I and IGFBP-3 were measured in 37 CF and 23 healthy subjects, whose mean ages were 5.02 +/- 3.06 and 5.27 +/- 2.82, respectively. The results were analyzed in relation to body mass index standard deviation scores (BMISD), height standard deviation scores (HSD), growth velocity standard deviation scores (GVSD), and clinical status assessed by Shwachman scores and pulmonary function parameters. RESULTS: Serum IGFBP-3 of CF patients showed significantly lower concentrations than healthy subjects (2457 vs. 3249 ng/mL) (P < 0.05), whereas IGF-I levels did not (123.35 vs. 149.8 ng/mL). There was significant positive correlation between IGF-I and IGFBP-3 with HSD (r = 0.62; r = 0.79) and BMISD (r = 0.39; r = 0.50). The pulmonary function tests in 14 CF subjects were not statistically worse than in nine healthy cases. The mean HSD (-0.67, SD 1.06) and BMISD (-0.28, SD 0.71) of CF patients were not significantly lower than those of healthy subjects (-0.02, SD 0.86 and 0.03, SD 0.49), respectively. CONCLUSION: Decreased serum IGF-I and IGFBP-3 levels may reflect growth retardation in CF. IGFBP-3 seems like a more sensitive parameter than IGF-I for growth monitoring in this study. Growth parameters of Turkish prepubertal CF patients are not markedly below national standards. Different genetic backgrounds of relevant populations certainly play an important role for the variable clinical course.

Curcumin's effects on sialic acid level and sialidase activity in Ehrlich ascites tumor bearing mice.

In this study, we determined curcumin's anticancer and chemopreventive effects in mice bearing Ehrlich ascites tumor by evaluation of cancer biomarkers, sialic acid level and sialidase activity. Both plasma sialic acid level and sialidase activity increased significantly in the mice group with Ehrlich ascites tumor. When the tumor groups fed with curcumin and fed with sesame oil were compared, sialic acid level and sialidase activity in ascites fluid significantly reduced in the group fed with curcumin in addition to the increases of plasma sialic acid level and sialidase activity. The tumor group fed with curcumin lived twice longer than the one fed with sesame oil. Curcumin as a phenolic compound decreased all these parameters in Ehrlich ascites tumors and lengthened survival by 88% in the mice with tumor. We concluded that curcumin has anticancer activity.