Elevated levels of neuropeptide Y in preeclampsia: A pilot study implicating a role for stress in pathogenesis of the disease.

OBJECTIVE: To determine if preeclampsia (PE) is associated with dysregulation of the neuropeptide Y (NPY) system. METHODS: The study enrolled 114 subjects either with normal pregnancy (NP) or with PE. Systolic blood pressure (SBP) was collected from patients using a standard sphygmomanometer. The PE patients were divided into two groups based on the gestational age (GA) at delivery - placental PE (PLPE, GA <34 weeks) or maternal PE (MTPE, GA ≥34 weeks). NPY was measured in platelet rich plasma (PRP), platelet poor plasma (PPP) and in the serum of NP and PE patients utilizing radioimmunoassay. Serum levels of soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) were measured in NP and PE subjects by ELISA. RESULTS: SBP was higher in PE compared to NP. Circulating NPY in serum and PRP, as well as NPY content per 100,000 platelets, but not its concentrations in PPP, were elevated in PE, as compared to NP. The highest NPY concentrations were observed in sera and PRP of patients with MTPE. PE patients had also elevated levels of sFlt-1, as compared to NP, although no difference between PLPE and MTPL groups were observed. There was no increase in P1GF in PE patients. CONCLUSION: Systemic NPY is elevated in PE patients, as compared to NP. This increase is observed in blood fractions containing platelets, suggesting accumulation of the peptide in these cells. NPY concentrations are particularly high in patients with MTPE, underlying differences in etiology between PLPE and MTPE. Our study implicates NPY as a potential target in antihypertensive therapies for PE patients.

Vitamin complex (ascorbic acid, alpha-tocopherol and beta-carotene) induces micronucleus formation in PBMNC unrelated to ROS production.

OBJECTIVES: To evaluate the correlation between reactive oxygen species (ROS) production and micronucleus formation induced by a vitamin complex in peripheral blood mononuclear cells from healthy people aged between 40 and 85 years old. METHODS: Peripheral blood mononuclear cells (PBMNCs) were purified utilizing ficoll-hypaque gradient. ROS production by PBMNCs was quantified by luminol-dependent chemiluminescence in the presence or in the absence of the vitamin complex. DNA damage in PBMNC by the vitamin complex was detected by the micronucleus technique. Statistical analyses were made with the Student's 't' test and the Pearson correlation. P < 0.05 was considered significant. RESULTS: The vitamin complex induced MN formation in PBMNC but did not augment ROS production. There was no correlation between ROS production and MN formation either in the presence or in the absence of the vitamin complex. DISCUSSION: There was no increase in the ROS production in the presence of the vitamin complex. The vitamin complex induced an augmentation in the MN formation. There was no correlation between ROS production and the induction of MN formation. Since no association could be detected between ROS production and MN formation, additional studies are required in order to investigate the possible mechanism of vitamin-induced MN formation.

Soluble RAGE and malondialdehyde in type 1 diabetes patients without chronic complications during the course of the disease.

Malondialdehyde (MDA), an end product of lipid peroxidation and biomarker for oxidative stress, and its soluble receptor (sRAGE) were evaluated in 42 patients with type 1 diabetes mellitus, but without chronic complications, during the early years after diagnosis (0-10 years) and through the further progression of the disease (10-20 and > 20 years after diagnosis). Clinical and biochemical parameters of the cohort of diabetic patients were compared with those determined in 24 healthy individuals. The median levels of MDA in plasma were similar in type 1 diabetes patients and in healthy subjects. In contrast, statistically significant increases were detected in the median values of sRAGE in patients with type 1 diabetes compared with healthy subjects (2423.75 versus 1472.75 pg/ml; p=0.001, Mann-Whitney test). However, no significant between-group differences (p>0.05) were observed in levels of sRAGE when diabetic patients were grouped according to time elapsed after diagnosis. It is concluded that increased plasma levels of sRAGE in type 1 diabetes may provide protection against cell damage and may be sufficient to eliminate excessive circulating MDA during early years after disease onset.

Determination of the antioxidant status of plasma from type 2 diabetic patients.

An increase in oxidizing response above a certain threshold produces, in the absence of a concomitant rise in antioxidant/reducing response, oxidative stress that is associated with complications in diabetes. A simple technique involving reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye has been developed in order to determine quantitatively the antioxidant status of plasma. MTT (50microL; 5.0mg/mL in PBS) was incubated with plasma (100microL) in PBS for 30, 60 or 120min at 37 degrees C, the reaction terminated by addition of 1.0mL of 0.04M hydrochloric acid in isopropanol and the absorbance measured at 570nm. The modulation by plasma of the generation of reactive oxygen species (ROS) in 12,13-phorbol dibutyrate (PDB)-stimulated granulocytes was evaluated using a chemiluminescence luminol-dependent assay. Plasma from healthy subjects (n=15) showed significantly higher antioxidant status (p<0.05) over all time periods studied compared with plasma from diabetic patients (n=27). MTT was directly reduced by plasma although platelets were not involved. Moreover, the reduction of MTT by bovine serum albumin at levels equivalent to the concentration of human serum albumin in plasma was much lower. The antioxidant status of plasma, as evaluated by MTT dye reduction, may reflect an antioxidant response since ROS generation in PDB-stimulated granulocytes was rapidly down-regulated by the presence of plasma (3.3-fold in diabetic patients and 5.8-fold in healthy subjects) confirming the lower antioxidant activity of plasma from diabetic patients. The results demonstrate that extracellular reduction of MTT by plasma may occur via enzymatic and non-enzymatic processes.