Vidosava Djordjevic

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-β-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.

Toxic essential oils. Part II: Chemical, toxicological, pharmacological and microbiological profiles of Artemisia annua L. volatiles

Botanical drugs based on Artemisia annua L. (Asteraceae) are important in the treatment of malaria. Alongside with artemisinin, this aromatic species produces high and variable amounts of other chemicals that have mostly unknown biological/pharmacological activities. Herein, we have studied the toxicological/pharmacological profile of volatile constituents of a Serbian population of A. annua. Fifty-eight components were identified, among them, artemisia ketone (35.7%), α-pinene (16.5%) and 1,8-cineole (5.5%) were the most abundant ones. Significant variability of A. annua volatile profile was confirmed by means of agglomerative hierarchical cluster analysis indicating the existence of several different A. annua chemotypes. In an attempt to connect the chemical profile of A. annua oil with its biological/toxicological effects, we have evaluated in vivo and/or in vitro toxicity (including hepato- and nephrotoxicity/protection), antinociceptive, antioxidant (DPPH, ABTS and superoxide radical scavenging activity assays), enzyme inhibiting (protein kinase A and α-amylase) and antimicrobial potential of A. annua oil and of its constituents. Our results revealed that the beneficial properties of A. annua botanical drugs are not limited only to their antimalarial properties. Taking into account its relatively low toxicity, the usage of A. annua volatiles (at least of the herein studied population) does not represent a health risk.

Monotherapy with metformin: does it improve hypoxia in type 2 diabetic patients?

Abstract Metformin reduces blood glucose levels predominantly by inhibiting hepatic gluconeogenesis, although it also may enhance insulin receptor number or activity. The full effects of metformin are still poorly understood. In this study the effects of metformin on plasma xanthine oxidase (XO) activity, thiobarbituric acid-reactive substance (TBARS), lactate and fructosamine concentration as well as erythrocyte antioxidant enzyme activities were investigated in 46 patients with type 2 diabetes mellitus. All parameters were measured simultaneously just before metformin therapy (T0), 1 month (T1) and 2 months (T2) later. Results were compared with placebo and control group. We noted significant decrease in XO activity and in TBARS concentration (p<0.001) during monotherapy with metformin vs. placebo and T0 group. A significant correlation was observed between the activity of XO and the concentration of fructosamine (p<0.001). Erythrocyte glutathione peroxidase showed significantly lower activity in T2 group in comparison with T0 group (p<0.01). It is known that diabetic patients produce more TBARS as a result of enhanced free radical generation the source of which may also be the large amounts of XO produced following the conversion of xanthine dehydrogenase in hypoxic diabetic tissues. Thus, our results indirectly suggest that metformin can reduce toxic tissue damage through the inhibition on XO activity.

Polymorphisms of tumor-necrosis factor-α−308 and lymphotoxin-α + 250: Possible modulation of susceptibility to apoptosis in chronic lymphocytic leukemia and non-Hodgkin lymphoma mononuclear cells

Tumor necrosis factor alpha (TNF-α) and lymphotoxin alpha (LT-α) have been shown to play an important role in the pathogenesis of limphoproliferative disease. Both cytokines regulate cell-survival and cell-death in leukemic cells. TNF-α and LT-α are highly produced in chronic lymphotic leukemia (CLL) and non-Hodgkin lymphoma (NHL) patients. Genetic polymorphism within regulatory regions of these cytokine genes can alter their expression levels. This study investigates an influence of TNF-α−308 and LT-α + 250 polymorphisms on the activity of alkaline DNase in mononuclear cells of both patient groups as a potent biochemical marker of DNA fragmentation in the terminal phase of apoptosis. Study was performed on mononuclear cells of CLL and NHL patients. SNP were obtained by PCR-RFLP method. The activity of alkaline DNase was measured by spectrophotometric method. The study provided evidence of the influence of TNFG/A genotype and A alleles in the susceptibility to NHL, since the association of LT-αG/G genotype with CLL was observed. High-producing TNF-α−308/LT-α + 250 heterozygous haplotype is associated with high NHL incidence. The investigated SNP influence the activity of alkaline DNase in CLL and NHL patients. The observed polymorphisms may modulate susceptibility of leukemic cells to apoptosis by way of DNase activity.

Low Catalase Activity in Rats with Ureteral Ligation: Relation to Lipid Peroxidation

Progression of some renal diseases is characterized by generation of reactive oxygen metabolites that are also involved in the pathophysiology of obstructive nephropathy. Catalase activity and lipid peroxidation were investigated in rats with unilaterally (UUL) and bilaterally ligated ureters (BUL). Forty-eight hours after ligation, the animals were sacrificed, and enzyme activity as well as the malondialdehyde (MDA) concentration were measured in the plasma, kidneys and livers. The activity of catalase was significantly reduced in the plasma of the BUL rats and in the kidneys of both investigated groups. In the liver, catalase activity was decreased only in the BUL group. The MDA concentration in the plasma and kidneys of the BUL rats was significantly increased while in the liver it remained unchanged. These results suggest that lipid peroxidation in the induced uremic state could be responsible for catalase inactivation.

Plasma nitrite/nitrate concentrations in patients with schizophrenia

Abstract Background: Nitric oxide (NO) is known to be a signaling molecule with many physiogical functions including apoptotic process regulation. Since apoptosis may contribute to the pathophysiology of schizophrenia, this study was undertaken to determine the plasma concentrations of NO in schizophrenics. Methods: Nitrite/nitrate (NO2–/NO3–) concentrations were measured in plasma from 40 patients with schizophrenia, and 36 age- and gender-matched healthy persons using a colorimetric test. Results: Plasma NO2–/NO3– concentrations were significantly higher in patients with schizophrenia (102.8±34.7 μmol/L, p<0.0001) than in controls (69.2±13.2 μmol/L). Also, mean NO2–/NO3– values in female patients and controls were significantly higher (118.2±44.7 μmol/L, p<0.001; 74.8±16.1 μmol/L, p<0.05, respectively) compared to males (94.7±25.3 μmol/L, 67.6±10.8 μmol/L). Significant correlation was seen between plasma NO2–/NO3– concentrations and heredity, number of episodes and peripheral blood mononuclear cell (PBMC) caspase-3 activity, which was significantly higher in patients than in controls (p<0.05). There was no significant difference in NO2–/NO3– concentrations between patients with different Positive and Negative Syndrome Scale (PANSS) scores or between patients treated with haloperidol (97.2±31.2 μmol/L) and those treated with other atypical antipsychotic drugs (109.8±33.7 μmol/L). Both parameters showed no significant differences between smokers and non-smokers. Conclusions: This study showed that plasma NO2–/NO3– concentrations were significantly increased in patients with schizophrenia, being significantly higher in female than male patients, and showing a significant correlation with heredity, number of episodes and PBMC caspase-3 activity. These results suggest that NO could be considered an inducer or regulator of apoptosis in patients with schizophrenia. Clin Chem Lab Med 2010;48:89–94.

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

Abstract 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-α (TNF-α), 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-α 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-α 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-α 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. Clin Chem Lab Med 2008;46:1149–55.

Beta2-Microglobulin and Alpha1-Microglobulin as Markers of Balkan Endemic Nephropathy, a Worldwide Disease

Background: Urine beta2-microglobulin (beta2-MG) was mainly used as a tubular marker of Balkan endemic nephropathy (BEN) but recently alpha1-microglobulin (alpha1-MG) was proposed for the diagnosis of BEN. In this study, the potential of urine beta2-MG, alpha1-MG, albumin, and total protein in the differentiation of BEN from healthy persons and patients with glomerulonephritis (GN) and nephrosclerosis (NS) was examined. Methods: This study involved 47 patients with BEN, 36 with GN, 11 with NS, 30 healthy subjects from BEN families, and 46 healthy subjects from non-BEN families. Results: In BEN patients area under the curve (AUC) for urine beta2-MG (0.828) and alpha1-MG (0.782) was higher than for urine albumin (0.740), but in GN patients AUC for urine protein (0.854) and albumin (0.872) was significantly higher than for the two low molecular weight proteins. AUC for all four urinary markers in NS patients was significantly lower than in BEN patients, ranging between 500 and 595. Median urine beta2-MG excretion in BEN patients was 17.5 times higher than in GN patients and 18.3 times higher than in controls; median alpha1-MG excretion was higher only 3.0 and 2.25 times, respectively. In the differentiation of BEN from healthy controls, beta2-MG had higher sensitivity and specificity at the cutoff levels (p < 0.001) than alpha1-MG (p < 0.05). In the differentiation of BEN from GN, beta2-MG was the best marker. Conclusion: All four urinary markers can be used for the differential diagnosis of BEN, beta2-MG being the best. Like in aristolochic acid nephropathy, beta2-MG seems to be an early marker of tubular damage in BEN.

δ-Aminolevulinic acid dehydratase activity in erythrocytes of diabetic patients

Erythrocytes delta-aminolevulinate dehydratase activity was assayed in 41 diabetic patients and 33 normal controls. It was found that in diabetic patients the erythrocyte ALA-D activity was lower than in controls, and the difference of the mean values was statistically highly significant (P less than 0.001). We found a significant negative correlation (r = - 0.846, P less than 0.001) between ALA-D activity and blood glucose levels. For this reason, using normal adult human whole blood haemolysates, it was investigated the effects in vitro of glucose and insulin on normal erythrocytic ALA-D. No significant difference in ALA-D activity was found in the presence of insulin. On the other hand, there was considerable decrease in the enzyme activity in the blood samples after glucose addition.

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

Abstract 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 µmol/l), compared to the control group (41.24 ± 3.65 µmol/l), while group I showed statistically lower values (32.38 ± 3.37 µmol/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.