Advanced glycation end products and antioxidant status in nondiabetic and streptozotocin induced diabetic rats: effects of copper treatment

The effects of Cu(II) supplementation on glycemic parameters, advanced glycation end products (AGEs), antioxidant status (glutathione; GSH and total antioxidant capacity; TAOC) and lipid peroxidative damage (thiobarbituric acid-reactive substances, TBARS) were investigated in streptozotocin (STZ) induced diabetic rats. The study was carried out on Wistar albino rats grouped as control (n = 10), CuCl₂ treated (n = 9), STZ (n = 10) and STZ,CuCl₂ treated (n = 9). STZ was administered intraperitoneally at a single dose of 65 mg/kg and CuCl₂, 4 mg copper/kg, subcutaneously, every 2 days for 60 days. At the end of this period, glucose(mg/dl), Cu(μg/dl), TBARS(μmol/l), TAOC(mmol/l) were measured in plasma, GSH(mg/gHb) in erythrocytes and glycated hemoglobin (GHb)(%) in blood. Plasma AGE-peptides(%) were measured by HPLC flow system with spectrofluorimetric and spectrophotometric detectors connected on-line. Data were analyzed by the non-parametric Kruskal–Wallis and Mann–Whitney U test. In the STZ group glucose, GHb and AGE-peptide levels were all significantly higher than the control group (P < 0.01, P < 0.05, and P < 0.01, respectively). CuCl₂ treated group had significantly lower glucose but significantly higher GHb, TAOC and TBARS levels than the control group (P < 0.05, P < 0.001, P < 0.05 and P < 0.001, respectively). STZ,CuCl₂ treated group had significantly higher GHb, TAOC and TBARS levels compared with the control group (P < 0.001, P < 0.05 and P < 0.05, respectively); but only TAOC level was significantly higher than the STZ group (P < 0.01). This experimental study provides evidence that copper intake increases total antioxidant capacity in both nondiabetic and diabetic states. However despite the potentiated antioxidant defence, lipid peroxidation and glycation enhancing effects of CuCl₂ are evident under nondiabetic conditions.     

Regulation of NF-κB signaling by oxidized glycerophospholipid and IL-1β induced miRs-21-3p and -27a-5p in human aortic endothelial cells

Exposure of endothelial cells (ECs) to agents such as oxidized glycerophospholipids (oxGPs) and cytokines, known to accumulate in atherosclerotic lesions, perturbs the expression of hundreds of genes in ECs involved in inflammatory and other biological processes. We hypothesized that microRNAs (miRNAs) are involved in regulating the inflammatory response in human aortic endothelial cells (HAECs) in response to oxGPs and interleukin 1β (IL-1β). Using next-generation sequencing and RT-quantitative PCR, we characterized the profile of expressed miRNAs in HAECs pre- and postexposure to oxGPs. Using this data, we identified miR-21-3p and miR-27a-5p to be induced 3- to 4-fold in response to oxGP and IL-1β treatment compared with control treatment. Transient overexpression of miR-21-3p and miR-27a-5p resulted in the downregulation of 1,253 genes with 922 genes overlapping between the two miRNAs. Gene Ontology functional enrichment analysis predicted that the two miRNAs were involved in the regulation of nuclear factor κB (NF-κB) signaling. Overexpression of these two miRNAs leads to changes in p65 nuclear translocation. Using 3′ untranslated region luciferase assay, we identified 20 genes within the NF-κB signaling cascade as putative targets of miRs-21-3p and -27a-5p, implicating these two miRNAs as modulators of NF-κB signaling in ECs.     

Assessment of DNA damage in women using oral contraceptives

The effect of the use of an oral contraceptive (OC) on the frequency of sister chromatid exchanges (SCEs) and on the response in the alkaline comet assay (single-cell gel electrophoresis (SCGE)) was investigated in 18 women taking contraceptive pills daily for 24 months. As controls, fertile women were included with regular menstrual cycles who received no OC drugs. A significant increase in the number of lymphocytes with DNA migration and an increased frequency of SCE per metaphase were observed in OC users as compared with their age-matched untreated controls (P<0.005). As higher incidences of spontaneous SCEs in peripheral blood lymphocytes have been reported to occur in females during pregnancy due to profound changes in the levels of certain sex hormones such as progesterone and estrogen, particularly during the last trimester, 17 pregnant women served as positive controls in this study in order to test the rate of genetic damage due to those changes. Higher frequencies of SCEs and comet responses were observed in pregnant women than in their matched controls. However, no statistically significant difference in DNA damage was observed between OC users and pregnant women (P>0.05). This study underscores the fact that prolonged and extensive use of these drugs in our daily life may be hazardous and also, that OC users should be aware of multifactorial risk factors (environmental, genetic and life style patterns) that may be responsible for additional DNA damage.     

Chromosomal aberrations under basal conditions and after treatment with X-ray in human lymphocytes as related to the GSTM1 genotype

The frequency of chromosomal aberrations (CAs) was evaluated in blood lymphocytes from 18 healthy subjects. Basal CA frequencies were not significantly different in GSTM1 positive and GSTM1 null subjects (P>0.05), whereas they were considerably higher in smokers than in non-smokers. After 1 Gy dose of X-ray challenge of blood samples, CA frequencies were significantly higher in GSTM1 null subjects, compared to GSTM1 positive subjects (P<0.005), and in smokers, compared to non-smokers. These effects are ascribed to the influence of GSTM1 genotype and of smoking status on DNA repair capacities. As the induction of CAs are associated with carcinogenesis, the challenge assay is able to detect enhanced susceptibility for CA caused by genetic predisposition of DNA repair deficiency.     

Smooth muscle cells contract in response to fluid flow via a Ca2+-independent signaling mechanism.

Smooth muscle cells (SMC) are exposed to fluid shear stress because of transmural (interstitial) flow across the arterial wall. This shear stress may play a role in the myogenic response and flow-mediated vasomotion. We, therefore, examined the effects of fluid flow on contraction of rat aortic SMC. SMC that had been serum-starved to induce a contractile phenotype were plated on quartz slides and exposed to controlled shear stress levels in a flow chamber. The area of the cells was quantified, and reduction in the cell area was reported as contraction. At 25 dyn/cm(2), significant area reduction was apparent 3 min after the onset of flow and exceeded 30% at 30 min. At 1 dyn/cm(2), significant contraction was not observed at 30 min. The threshold for significant shear-induced contraction appeared to be 11 dyn/cm(2). The signal transduction mechanism was studied at 25 dyn/cm(2). Intracellular calcium was imaged by using the calcium-sensitive fluorescent dye fura 2-AM. There was no detectable change in intracellular calcium during 10 min of exposure to shear stress, even though the cells displayed a significant calcium response to thapsigargin, calcium ionophore, and KCl. Further studies using pathway inhibitors provided evidence that the most important signal transduction pathway mediating calcium-independent contraction in response to fluid flow is the Rho-kinase pathway, although there was a suggestion that protein kinase C plays a secondary role.     

Genetic Control of Obesity and Gut Microbiota Composition in Response to High-Fat,High-Sucrose Diet in Mice

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Highlights? Detailed analysis of diet-induced obesity in more than 100 inbred mouse strains ? Identification of 11 genetic loci associated with obesity and dietary responsiveness ? Significant overlap between mouse loci with human GWAS loci for obesity ? Strain-specific shifts in gut microbiota composition in response to dietary intervention     

Pollen counts and their relationship to meteorological factors in Ankara,Turkey during 2005–2008

Pollen plays an important role in the development and exacerbation of allergic diseases. We aimed to investigate the days with highest counts of the most allergenic pollens and to identify the meteorological factors affecting pollen counts in the atmosphere of Ankara, Turkey. Airborne pollen measurements were carried out from 2005 to 2008 with a Burkard volumetric 7-day spore trap. Microscope counts were converted into atmospheric concentrations and expressed as pollen grains/m³. Meteorological parameters were obtained from the State Meteorological Service. All statistical analyses were done with pollen counts obtained from March to October for each year. The percentages of tree, grass and weed pollens were 72.1% (n = 24,923), 12.8% (n = 4,433) and 15.1% (n = 5,219), respectively. The Pinaceae family from tree taxa (39% to 57%) and the Chenopodiaceae/Amaranthaceae family from weed taxa, contributed the highest percentage of pollen (25% to 43%), while from the grass taxa, only the Poaceae family was detected from 2005 to 2008. Poaceae and Chenopodiaceae/Amaranthaceae families, which are the most allergenic pollens, were found in high numbers from May to August in Ankara. In multiple logistic regression analysis, wind speed (OR = 1.18, CI95% = 1.02–1.36, P = 0.023) for tree pollen, daily mean temperature (OR = 1.10, CI95% = 1.04–1.17, P = 0.001) and sunshine hours (OR = 1.15, CI95% = 1.01–1.30, P = 0.033) for grass pollen, and sunshine hours (OR = 3.79, CI95% = 1.03–13.92, P = 0.044) for weed pollen were found as significant risk factors for high pollen count. The pollen calendar and its association with meteorological factors depend mainly on daily temperature, sunshine hours and wind speed, which may help draw the attention of physicians and allergic patients to days with high pollen counts.