The Differences in the Cellular and Plasma Antioxidative Capacity Between Transient and Defined Focal Brain Ischemia: Does it Suggest Supporting Time-Dependent Neuroprotection Therapy?

There are many opened questions about the precocious role of oxidative stress in the physiopathology of the early stage of transitory ischemic attack (TIA) and defined focal brain ischemia, as well as about its correlation with clinical severity, short-lasting and clinical outcome prediction in these conditions. The study evaluates the values of glutathione (GSH), glutathione peroxidase, and superoxide dismutase (SOD) in hemolysates and total thiol content (-SH), advanced oxidation protein products (AOPP), SOD, and malondialdehyde (MDA) in plasma, in TIA and stroke patients in the early stage of their neurological onset. The results are interpreted in view of the potential relationship between tested parameters and clinical severity and clinical outcome prediction. Better hemolysates' and total antioxidant profile with higher values of AOPP were observed in TIA compared to stroke patients (p < 0.05). The stroke patients with initially better clinical presentation showed better antioxidant profile with lower values of AOPP (p < 0.05). In TIA patients, this was observed for GSH, -SH content, and AOPP (p < 0.05), which correlated with a short risk for stroke occurrence in this group (p < 0.01). Beyond MDA values, all tested parameters showed correlation with clinical outcome in stroke patients (p < 0.05). The measurement of oxidative stress in TIA and stroke patients would be important for identifying patients' subgroups which might receive supporting therapy providing better neurological recovery and clinical outcome. That approach might give us an additional view of a short-lasting risk of stroke occurrence after TIA, and its clinical outcome and prognosis.

Transforming growth factor beta1, matrix-metalloproteinase-2 and its tissue inhibitor in patients with pseudoexfoliation glaucoma/syndrome.

BACKGROUND/AIM: Transforming growth factor-beta1 (TGF-beta1), oxidative stress and imbalance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) may play an important role in pathogenesis of pseudoexfoliation syndrome/glaucoma (PEX Sy/Gl). The aim of the study was to measure concentrations of TGF-beta1, MMP-2, TIMP-2 in the aqueous humor in the examined group, as well as to compare the biochemical findings with the following clinical parameters: degree of chamber angle pigmantation, presence of pseudoexfoliation and the value of intraocular pressure (IOP). METHODS: Aqueous samples from 30 patients with cataract, 30 patients with PEX Sy, 36 patients with PEX Gl, and 42 patients with primary open-angle glaucoma (POAG) were collected during phacoemulsification cataract surgery. TGF beta1, MMP-2, TIMP-2 Fluotokine Multi Analyze Profiling kits and Luminex technology were used to simultaneously measure TGF beta1, MMP-2 and TIMP-2. RESULTS: TGF-beta1, MMP-2, TIMP-2 were detected in human aqueous from all the groups with the highest level in the group with PEX Gl. Statistically, a significant correlation between the levels of TGF beta1, MMP-2, TIMP-2 in the aqueous humor of the patients with PEX Gl and the IOP value was confirmed (p < 0.05). In this group, the positive correlations between the TGF beta1 concentration in the aqueous humor and the presence of pseudoexfoliation (p < 0.01), on the one hand, and between the TIMP-2 level and the presence of pseudoexfoliation (p < 0.05), on the other, were reported. A statistically significant positive correlation of TGF-beta1 and MMP-2, and the degree of chamber angle pigmentation in the PEX Gl group was confirmed (p < 0.05). In the POAG group, TIMP-2 values were in a negative correlation with the degree of pigmentation (p < 0.05), and the IOP value (p < 0.05). CONCLUSION: TGF beta1 and MMP-2 affect the degree of chamber angle pigmentation and the degree of pseudoexfoliation in patients with pseudoexfoliative glaucoma.

Lipoprotein(a) Is the Best Single Marker in Assessing Unstable Angina Pectoris.

This study evaluated whether statin therapy changed a diagnostic validity of lipid and inflammatory markers in ischemic heart disease (IHD) patients. Levels of lipids, lipoproteins, apolipoproteins, inflammatory markers, and atherogenic indexes were determined in 49 apparently healthy men and women, 82 patients having stable angina pectoris (SAP), 80 patients with unstable angina (USAP), and 106 patients with acute ST-elevation myocardial infarction (STEMI) treated or not treated with statins. Diagnostic accuracy of markers was determined by ROC curve analysis. Significantly lower apoA-I in all statin-treated groups and significantly higher apoB in statin-treated STEMI group compared to non-statin-treated groups were observed. CRP showed the best ROC characteristics in the assessment of STEMI patients. Lp(a) is better in the evaluation of SAP and USAP patients, considering that Lp(a) showed the highest area under the curve (AUC). Regarding atherogenic indexes, the highest AUC in SAP group was obtained for TG/apoB and in USAP and STEMI patients for TG/HDL-c. Statins lowered total cholesterol, LDL-c, and TG but fail to normalize apoA-I in patients with IHD.

[Oxidative stress in human diseases].

Oxidative stress is a "privilege" of aerobic organisms. It can be induced by endogenous and exogenous factors. Most often, it is characterized by the production of free radicals and nonradical oxygen and nitrogen products, referred to under a single term "reactive species" (RS). Oxidative stress is a deleterious process that can be an important mediator of damage to cell structures, including lipids and membranes, proteins and DNA. However, reactive oxygen (ROS) and nitrogen species (RNS) are "two-faced" products. Produced in low/moderate concentrations as molecular signals that regulate a series of physiological processes, such as a defence against infectious agents, the maintenance of vascular tone, the control of ventilation and erythropoietin production, and signal transduction from membrane receptors in various physiological processes. Many of ROS-mediated responses protect cells against oxidative stress and maintain "redox homeostasis". Then, both reactive species are produced by strictly regulated enzymes, such as nitric oxide synthase (NOS), and isoforms of NADPH oxidase, or as by-products from not so well regulated sources, such as the mitochondrial electron-transport chain. An excessive increase in ROS production has been implicated in the pathogenesis of atherosclerosis, cardiovascular diseases, hypertension, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative and immuno-inflammatory diseases. Within the cells, ROS can act as secondary messengers in intracellular signalling cascades, which can induce the oncogenic phenotype of cancer cells, cellular senescence and apoptosis.

Serum neopterin, nitric oxide, inducible nitric oxide synthase and tumor necrosis factor-alpha levels in patients with ischemic heart disease.

BACKGROUND: Atherosclerosis, a chronic inflammatory disease, underlies the pathogenesis of coronary artery disease. The present study assessed the diagnostic possibilities of inflammatory biomarkers, serum neopterin, nitrite/nitrate (NO2(-)/NO3(-)), inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha), and their correlation with risk factors in patients with acute coronary syndromes and stable angina pectoris. METHODS: We studied 44 patients with chronic stable angina pectoris, 46 with unstable angina, 55 with acute ST-elevation myocardial infarction and 39 age-matched healthy volunteers (control group). Serum neopterin, iNOS and TNF-alpha were determined with commercially available enzyme linked immunosorbent assay methods and NO2(-)/NO3(-) by the modified cadmium-reduction method. RESULTS: Mean serum neopterin levels were significantly higher in patients with unstable and stable angina pectoris in comparison to control subjects (p<0.01 and p<0.05, respectively). Serum NO2(-)/NO3(-) values were significantly elevated (p<0.01) only in patients with unstable angina. ST-elevation myocardial infarction patients with cardiac death during follow-up showed significantly lower baseline neopterin values (p<0.001), and higher NO2(-)/NO3(-) levels (p<0.05) in comparison to those without adverse events. Significantly higher NO2(-)/NO3(-) values (p<0.05) were also found in patients who had myocardial reinfarction. Serum iNOS and TNF-alpha in all patient groups were within control ranges. A strong correlation was found between neopterin and both smoking (p<0.01) and triglycerides (p<0.05) in unstable angina patients. In stable angina patients, neopterin, iNOS and TNF-alpha significantly correlated with hypertension (p<0.01) and triglycerides (p<0.05). A significant difference in neopterin concentration was found between smokers and non-smokers (p<0.05). CONCLUSIONS: The results of this study suggest that in stable angina patients, if studied over time, serum neopterin or NO2(-)/NO3(-) levels may indicate future plaque instability. In ST-elevation myocardial infarction patients, neopterin and/or NO2(-)/NO3(-) levels may identify patients at long-term risk of death or recurrent acute coronary events after myocardial infarction.

Effects of aerobic exercise on microalbuminuria and enzymuria in type 2 diabetic patients.

Increased urinary albumin excretion is a strong predictor for the development of overt diabetic nephropathy and overall cardiovascular morbidity and mortality in patients with type 2 diabetes. In a previous study, regular aerobic physical activity in overweight/obese patients with type 2 diabetes mellitus was found to have significant beneficial effects on glycemic control, insulin resistance, cardiovascular risk factors, and oxidative stress. The aim of the present study was to investigate the effects of aerobic exercise in the same cohort of type 2 diabetic patients on urinary albumin excretion, serum levels and urinary excretion of enzymes, tubular damage, and metabolic control markers in type 2 diabetic patients. Changes from baseline to 3 and 6 months of aerobic exercise were assessed for urinary albumin excretion, serum activities, and urinary excretion of N-acetyl-beta-D-glucosaminidase (NAGA), plasma cell glycoprotein 1 (PC-1) and aminopeptidase N (APN), as well as their association with insulin resistance, cardiovascular risk factors, and oxidative stress parameters in 30 male type 2 diabetic patients (aged 54.8 +/- 7.3 years, with a mean BMI of 30.8 +/- 3.0 kg/m2). Microalbuminuria was found in six (20%) diabetic patients at baseline, three of them (10%) after three months, and only one patient (3.33%) at the end of the study period. A significant correlation was found for urinary albumin excretion at baseline both with sulfhydryl-groups and catalase, but not for urinary albumin excretion with MDA and glutathione. The prevalence of microalbuminuria tended to decrease after six months of aerobic exercise in type 2 diabetic patients, independently of any improvement in insulin resistance and oxidative stress parameters. Neither between-group nor within-group changes were found for urinary PC-1, APN, and NAGA activity. Serum NAGA was significantly increased (p < 0.05) over the control level in diabetic patients at baseline, but it decreased to the normal level after six months of exercise. This study has shown that a six-month aerobic exercise, without any change in the medication, tended to decrease microalbuminuria without changing enzymuria. However, further studies are needed not only to confirm those findings, but to elucidate potential mechanisms that would clarify the beneficial effects of exercise.

[Importance of breast-feeding in antioxidant defence].

We investigated the importance of two enzymes (superoxide dismutase--SOD and glutathione peroxidase--GSH-Px) in the antioxidant defence of newborns and analysed their activity in: human colostrum and milk (from 63 mothers, after normal delivery, without complications or signs of infection), gastric fluid (from 10 breast-fed newborns, 7-28 days after birth; and from 15 artificially-fed newborns, with no signs of infection, 7-28 days after birth), and plasma (from 10 newborns, 1-28 days old, with no signs of infection, and 10 newborns, 1-28 days old, with signs of neonatal sepsis). The results of the study showed that there was statistically significant increased activity of SOD (p<0.001) in colostrum compared to mature milk. There was no statistically important difference in the activity of GSH-Px between those two samples. The activity of SOD in the gastric fluid of the artificially-fed newborns was statistically significantly lower than in the breast-fed newborns (p<0.001). The same results were found for mature mother's milk. We discovered a significant increase of SOD plasma activity in the newborns with sepsis, compared to the breast-fed newborns, with no signs of infection. The negative correlation between the activities of SOD and GSH-Px in the gastric fluid samples of the breast-fed and the artificially-fed newborns and the newborns with sepsis, showed that the activities of both enzymes were important for adequate antioxidant defence during the neonatal period. Breast-feeding with both colostrum and mature human milk is probably very important for adequate antioxidant defence in newborns.

Immune system-mediated endothelial damage is associated with NO and antioxidant system disorders.

Two distinct systems of different origin are involved in the pathogenesis of both infectious and immunological vasculitis syndrome: nitric oxide (NO) from endothelial cells and granulocyte NADPH oxidase. In this study, in 31 children with immune system dysfunction, NO, NO synthase (NOS) and antioxidant enzyme activities [catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx)], as well as immunological parameters, were investigated. On the basis of the clinical findings, all children were divided into three groups: group I, 8 children clinically showing macular skin manifestations; group II, 11 children with maculo-papulous changes; and group III, 12 children with clinical findings of papulous changes. Plasma NO values in groups II and III were significantly elevated (79.14+/-30.13 and 65.32+/-6.70 micromol/l), compared to the control group (41.24+/-3.65 micromol/l), while group I showed statistically lower values (32.38+/-3.37 micromol/l). In children with the highest level of NO (group II) NOS activity was two-fold higher (1.77+/-0.59 nmol/ml/min; p<0.01) than in controls (0.98+/-0.23 nmol/ml/min). Catalase activity showed a significant increase and SOD activity a significant decrease in all experimental groups, while GPx was not significantly changed. The results show that immune system dysfunction manifested as vasculitis is associated with significant disturbances in the NO system and free radicals scavengers.