Aleš Žák

Antioxidative enzymes and increased oxidative stress in depressive women

OBJECTIVES To investigate the activities of the main antioxidative enzymes and oxidative stress in women with depressive disorder (DD). METHODS In 35 drug-naive women with DD and 35 age matched healthy women enzymes superoxide dismutase (CuZnSOD), catalase (CAT), glutathione peroxidase (GPX1), glutathione reductase (GR) and paraoxonase (PON1), concentrations of conjugated dienes (CD), reduced glutathione (GSH) and anthropometric and clinical data were investigated. RESULTS Women with DD were found to have decreased activities of GPX1 (p<0.05), decreased concentrations of GSH (p<0.05), and increased activities of GR (p<0.05), CuZnSOD (p<0.001), and concentrations of CD (p<0.05). Activity of GPX1 was positively correlated with concentration of GSH (p<0.05). Concentrations of CD were positively correlated with TG (p<0.01). CONCLUSION Our set of depressive women was characterized by changes indicating an increased oxidative stress, as well as by certain features of metabolic syndrome.

Analysis of fatty acids in plasma lipoproteins by gas chromatography–flame ionization detection: Quantitative aspects

Abstract Profiles of fatty acids in lipid classes of plasma and ultracentrifugally separated lipoproteins were analyzed by capillary gas chromatography. Contribution of individual steps of the whole procedure was calculated on the basis of the multiple analyses. GC contributes to the overall error by the smallest part. Contribution of the extraction, thin-layer chromatography separation and methylation processes might be comparable. The value of relative standard deviation is indirectly proportional to the amount of analyzed component. Comparison of FA profiles in lipid classes of very low density lipoproteins and low density lipoproteins revealed highly individual differences. Increased content of arachidonic and docosahexaenoic acids in triglycerides of low density lipoproteins are in agreement with formerly published results. Duplicate analyses are recommended for the evaluation of differences between FA composition in individual lipoproteins.

Soluble receptor for advanced glycation end-products (sRAGE) and polymorphisms of RAGE and glyoxalase I genes in patients with pancreas cancer.

OBJECTIVES The receptor for advanced glycation end-products (RAGE) takes part in the pathogenesis of many diseases, including diabetes mellitus and cancer. AGE-precursors are detoxified by glyoxalase (GLO). sRAGE, soluble RAGE, is an inhibitor of pathological effects mediated via RAGE. The aim was to study sRAGE and polymorphisms of RAGE (AGER) and GLO genes in patients with pancreas cancer (PC). DESIGN AND METHODS The studied group consisted of 51 patients with PC (34 with impaired glucose tolerance-IGT, 17 without IGT), 34 type 2 DM and 154 controls. For genetic analysis, the number of patients was increased to 170. Serum sRAGE was measured by ELISA and all polymorphisms (RAGE -429T/C, -374T/A, 2184A/G, Gly82Ser and GLO A419C) were determined by PCR-RFLP and confirmed by sequencing. RESULTS Soluble RAGE is decreased in patients with PC compared to patients with DM and controls (975+/-532 vs. 1416+/-868 vs. 1723+/-643pg/mL, p<0.001). Patients with PC and IGT have lower sRAGE levels compared to patients with PC without IGT (886+/-470 vs. 1153+/-616pg/mL, p<0.05). No relationship of sRAGE to the stage was found. We did not show any difference in allelic and genotype frequencies in all RAGE and GLO polymorphisms among the studied groups. CONCLUSION This is the first study demonstrating decreased sRAGE in patients with pancreas cancer. Its levels are even lower than in diabetics and are lowest in patients with PC and IGT. Our study supports the role of glucose metabolism disorder in cancerogenesis. Further studies are clearly warranted, especially with respect to potential preventive and therapeutic implications.

Altered Activities of Antioxidant Enzymes in Patients with Metabolic Syndrome

Objective: In the pathogenesis of the metabolic syndrome (MetS), an increase of oxidative stress could play an important role which is closely linked with insulin resistance, endothelial dysfunction, and chronic inflammation. The aim of our study was to assess several parameters of the antioxidant status in MetS. Methods: 40 subjects with MetS and 40 age- and sex-matched volunteers without MetS were examined for activities of superoxide dismutase (CuZnSOD), catalase (CAT), glutathione peroxidase 1 (GPX1), glutathione reductase (GR), paraoxonase1 (PON1), concentrations of reduced glutathione (GSH), and conjugated dienes in low-density lipoprotein (CD-LDL). Results: Subjects with MetS had higher activities of CuZnSOD (p < 0.05) and GR (p < 0.001), higher concentrations of CD-LDL (p < 0.001), lower activities of CAT (p < 0.05) and PON1 (p < 0.05), and lower concentrations of GSH (p < 0.05), as compared with controls. Activity of GPX1 was not significantly changed. Conclusions: Our results implicated an increased oxidative stress in MetS and a decreased antioxidative defense that correlated with some laboratory (triglycerides, high-density lipoprotein cholesterol (HDL-C)) and clinical (waist circumference, blood pressure) components of MetS.

Plasma Fatty Acid Composition in Patients with Pancreatic Cancer: Correlations to Clinical Parameters

Pancreatic cancer (PC) ranks as the fourth cause of cancer-related deaths in the Czech Republic. Evidence exists that deregulation of fatty acid (FA) metabolism is connected with some malignancies; therefore, we decided to analyze FA profile in plasma lipid classes in patients with PC with relation to tumor staging, nutritional status, and survival. The study included 84 patients (47 males, 37 females) with PC and 68 controls (36 males, 32 females). FA patterns were analyzed in plasma lipid classes by gas-chromatography. We observed increased proportion of total monounsaturated FA (MUFA) in PC group in all plasma lipid classes. These changes were connected with increased Δ9-desaturase (SCD1) and Δ5-desaturase indices. Correlations of dihomo-γ-linolenic acid (DHGLA) with these variables were opposite. Longer survival of patients was connected with higher content of EPA, DHA, and with lower SCD1 index, respectively. Plasma phospholipid proportions of α-linolenic acid, DHGLA, EPA, and n-3 polyunsaturated fatty acids displayed negative trend with tumor staging. Plasma lipid FA pattern in PC patients resulted from decreased dietary fat intake and increased de novo synthesis of FA with transformation into MUFA. Changes in FA profile implicated some pathophysiological mechanisms responsible for disturbed FA metabolism in PC and importance of appropriate nutritional support.

The influence of polymorphism of −493G/T MTP gene promoter and metabolic syndrome on lipids, fatty acids and oxidative stress

The aim of this study was to investigate the effect of the microsomal triglyceride transfer protein (MTP) -493G/T polymorphism on clinical and biochemical parameters in relation to the presence of metabolic syndrome (MS). A group of 270 participants, 143 men and 127 women [50 men/36 women fulfilled the International Diabetes Federation (IDF) criteria of MS], was categorized on the basis of the MTP -493G/T polymorphism: GG homozygotes (Group GG) and carriers of the T allele (Group TT+TG). In men with MS, the presence of the T allele was associated with elevated concentrations of plasma insulin (by 48%, P<.01) and nonesterified fatty acids (by 49%, P<.05); homeostasis model assessment for insulin resistance index was higher by 64% (P<.05). Carriers of the T allele were further characterized by elevated plasma concentrations of total cholesterol (by 14%, P<.05) and by increased triglycerides in plasma (by 95%, P<.01) and in very low-density lipoprotein (by 106%, P<.01). They also had lower concentrations of n-6 polyunsaturated fatty acids in plasma phospholipids (by 3.5%, P<.05), lower Delta5-desaturase activities (by 18%, P<.05) and elevated concentrations of conjugated dienes in low-density lipoprotein (by 29%, P<.01). No significant differences between Groups GG and TT+TG were found in men without MS and in women with and without MS. Our results imply evidence for interactive effects of genetic, metabolic and gender-specific factors on several components of metabolic syndrome, which can increase the risk for cardiovascular disease.

Effect of column and software on gas chromatographic determination of fatty acids

Four capillary columns (A: CP-WAX 52 CB 25 m x 0.25 mm; B: CP WAX 52 CB 30 m x 0.25 mm; C: CP-WAX 58 CB 25 m x 0.25 mm, Chrompack; D: OMEGAWAX 320 30 m x 0.32 mm, Supelco) and two integration software (Mosaic v.5.10, Chrompack and CSW v.1.7, Data Apex5) were compared for analysis of fatty acids. Column A was mounted stepwise in two different instruments. Fatty acids of blood plasma phosphatidylcholine and standard mixture of saturated fatty acids were analysed as methyl esters under identical chromatographic conditions. Both integrating software did not differ significantly in most results; differences were observed only for minor components: 16:1n9 (0.10+/-0.020 vs. 0.17 +/- 0.005 M%, P < 0.0001, column Al; 0.09 +/- 0.011 vs. 0.16 +/- 0.007 M%, P< 0.0001, column A2; 0.09 +/- 0.010 vs. 0.17 +/- 0.003 M%, P < 0.0001, column C; 0.09 +/ -0.008 vs. 0.19 +/- 0.003 M%, P < 0.0001, column D), 20:0 (0.10+0.001 vs. 0.06 +/- 0.005 M%, P < 0.05, column C) and 20:2n6 (0.43 +/- 0.030 vs. 0.91 +/- 0.016 M%, P < 0.0001, column A2). Increased values for 16:1n9 and 20:2n6 integrated by MOSAIC are caused by cointegration of two poorly resolved peaks: fatty acid and impurity from sample matrix. Lower values for 20:0 are caused by incomplete integration of minor peak. Differences between columns were observed mostly for minor fatty acids. The results indicate that CSW is more suitable software for integration of complicated chromatograms. Linear calibration dependences measured with standard mixture of saturated fatty acids (carbon number 10-24) were observed in wide range of concentrations (three orders). Slope close to unity and minimal value of intercept confirmed theoretical relations when analyses are run under optimal conditions. Use of one column is advisable in small intervention or experimental metabolic studies.

Pleiotropic effects of niacin: Current possibilities for its clinical use

Abstract Niacin was the first hypolipidemic drug to significantly reduce both major cardiovascular events and mortality in patients with cardiovascular disease. Niacin favorably influences all lipoprotein classes, including lipoprotein[a],and belongs to the most potent hypolipidemic drugs for increasing HDL-C. Moreover, niacin causes favorable changes to the qualitative composition of lipoprotein HDL. In addition to its pronounced hypolipidemic action, niacin exerts many other, non-hypolipidemic effects (e.g., antioxidative, anti-inflammatory, antithrombotic), which favorably influence the development and progression of atherosclerosis. These effects are dependent on activation of the specific receptor HCA2. Recent results published by the two large clinical studies, AIM-HIGH and HPS2-THRIVE, have led to the impugnation of niacin’s role in future clinical practice. However, due to several methodological flaws in the AIM-HIGH and HPS2-THRIVE studies, the pleiotropic effects of niacin now deserve thorough evaluation. This review summarizes the present and possible future use of niacin in clinical practice in light of its newly recognized pleiotropic effects.

Chronic pancreatitis and the composition of plasma phosphatidylcholine fatty acids.

Chronic pancreatitis (CP) is an irreversible inflammatory disorder characterized by the destruction of both exocrine and endocrine tissue. There is growing evidence that dysregulation of fatty acid (FA) metabolism is connected with many diseases; however, there are few data concerning FA composition in CP. Therefore, we analyzed FA profiles in plasma phosphatidylcholines in 96 patients with CP and in 108 control subjects (CON). The patients with CP had, in comparison with CON, increased sum of monounsaturated FA (ΣMUFA) and decreased content of polyunsaturated FA (PUFA) in both n-6 and n-3 families. Moreover, CP patients had increased indexes for delta-9, delta-6 desaturases, and fall in activity of delta-5 desaturase. Increased ratio of 16:1n-7/18:2n-6 (marker of essential n-6 FA deficiency), was more prevalent among CP patients. These changes implicated decreased fat intake, including n-3 as well as n-6 PUFA, and intrinsic changes in FA metabolism due to the alteration of delta desaturase activities.

Lipid Metabolism in Patients with End-Stage Renal Disease: A Five Year Follow-up Study

BACKGROUND Patients with end-stage renal disease (ESRD) exhibit high morbidity as well as mortality for atherosclerotic cardiovascular diseases (CVD). Therefore, we investigated differences in individual lipoprotein classes and subclasses in ESRD patients under chronic high volume hemodiafiltration (HV-HDF) in comparison with a control group. We also assessed the prognosis of these patients and analyzed these parameters after 5 years follow-up. METHODS 57 patients and 50 controls were enrolled. We analysed high density (HDL) and low density (LDL) lipoprotein subfractions using the Quantimetrix Lipoprint(R) system. Subfractions were correlated with selected clinical-biochemical parameters including risk factors for atherosclerotic CVD at the beginning of and after 5 years follow-up. RESULTS Fourteen patients survived the 5-year follow-up. Follow-up results revealed a shift toward smaller HDL subfractions. In lipoproteins carrying apolipoprotein B, there was a shift of cholesterol from very low density (VLDL) to intermediate density (IDL) lipoproteins and LDLs. Hypolipidaemic therapy did not influence lipoprotein profiles in HV-HDF patients. CONCLUSION 1. HV-HDF patients exhibit specific lipid profiles with elevated triacylglycerol, low HDL and LDL and higher content of cholesterol in remnant particles (VLDL and IDL) at the expense of large LDL. HDL subfractions were linked to the number of risk factors for CVD in the control group only. 2. Baseline lipoprotein profiles did not differ between survivors and non-survivors. Non-survivors had higher CRP and lower HDL-C. 3. During the 5 year follow-up period, cholesterol in HDL particles and lipoproteins carrying apolipoprotein B redistributed in survivors towards smaller particles, thus resembling the profile of control patients.