leptin and 3-nitrotyrosine

Particulate matter with a diameter ≤ 2.5 μm (PM2.5) affects human fetal development during pregnancy. Oxidative stress is a putative mechanism by which PM2.5 may exert its effects. Leptin (LEP) is an energy-regulating hormone involved in fetal growth and development.. We investigated in placental tissue whether DNA methylation of the LEP promoter is associated with PM2.5 and whether the oxidative/nitrosative stress biomarker 3-nitrotyrosine (3-NTp) is involved.. LEP DNA methylation status of 361 placentas from the ENVIRONAGE birth cohort was assessed using bisulfite-PCR-pyrosequencing. Placental 3-NTp (n = 313) was determined with an ELISA assay. Daily PM2.5 exposure levels were estimated for each mother's residence, accounting for residential mobility during pregnancy, using a spatiotemporal interpolation model.. After adjustment for a priori chosen covariates, placental LEP methylation was 1.4% lower (95% CI: -2.7, -0.19%) in association with an interquartile range increment (7.5 μg/m3) in second-trimester PM2.5 exposure and 0.43% lower (95% CI: -0.85, -0.02%) in association with a doubling of placental 3-NTp content.. LEP methylation status in the placenta was negatively associated with PM2.5 exposure during the second trimester, and with placental 3-NTp, a marker of oxidative/nitrosative stress. Additional research is needed to confirm our findings and to assess whether oxidative/nitrosative stress might contribute to associations between PM2.5 and placental epigenetic events. Potential consequences for health during the neonatal period and later in life warrant further exploration. Citation: Saenen ND, Vrijens K, Janssen BG, Roels HA, Neven KY, Vanden Berghe W, Gyselaers W, Vanpoucke C, Lefebvre W, De Boever P, Nawrot TS. 2017. Lower placental leptin promoter methylation in association with fine particulate matter air pollution during pregnancy and placental nitrosative stress at birth in the ENVIRONAGE cohort. Environ Health Perspect 125:262-268; http://dx.doi.org/10.1289/EHP38.

Topics: Biomarkers; DNA Methylation; Female; Humans; Leptin; Maternal Exposure; Oxidative Stress; Particulate Matter; Placenta; Pregnancy; Pregnancy Trimester, Second; Promoter Regions, Genetic; Tyrosine

We have previously shown that treating streptozotocin-induced diabetic rats, an animal model of type 1 diabetes, with Ilepatril (an inhibitor of neutral endopeptidase and angiotensin converting enzyme (ACE)) improves vascular and neural functions. In this study we sought to determine the effect of Ilepatril treatment of high fat fed/low dose streptozotocin-diabetic rats, a model for type 2 diabetes, on vascular and neural complications. Following 8 weeks on a high fat diet rats were treated with 30 mg/kg streptozotocin (i.p.) and after 4 additional weeks a group of these rats was treated for 12 weeks with Ilepatril followed by analysis of neural and vascular functions. Included in these studies were age-matched control rats and rats fed a high fat diet and treated with or without Ilepatril. Diabetic and diet induced obese rats have characteristics of insulin resistance, slowing of nerve conduction velocity, thermal hypoalgesia, reduction in intraepidermal nerve fiber density in the hindpaw and impairment in vascular relaxation to acetylcholine and calcitonin gene-related peptide in epineurial arterioles of the sciatic nerve. Treatment with Ilepatril was efficacious in improving all of these endpoints although improvement of insulin resistance in diabetic rats was minimal. These studies suggest that dual inhibition of angiotensin converting enzyme and neutral endopeptidase activity of type 2 diabetic rats is an effective approach for treatment of diabetic neural and vascular complications.

Topics: Adipose Tissue; Animals; Arterioles; Blood Glucose; Blood Vessels; Body Weight; Carbohydrate Metabolism; Diabetes Complications; Diabetes Mellitus, Experimental; Diet, High-Fat; Dose-Response Relationship, Drug; Enzyme Inhibitors; Glucose Tolerance Test; Glutathione; Heterocyclic Compounds, 3-Ring; Insulin; Lens, Crystalline; Leptin; Male; Muscle, Skeletal; Nerve Fibers; Nervous System; Nociception; Organ Size; Rats; Rats, Sprague-Dawley; Sciatic Nerve; Superoxides; Thiobarbiturates; Tyrosine; Vasodilation

Advanced glycation endproducts (AGEs) and oxidative stress (OS) contribute to the development and progression of diabetic complications. We have reported that dietary AGEs and OS induce acute endothelial dysfunction in vivo, but little is known about their effects on adipokines. Twenty inpatients with type 2 diabetes mellitus (mean age: 55.9; range: 32-71 years), received a standard diabetes diet for 6 days. On days 4 and 6, the acute effects of a high-AGE (HAGE) or a low-AGE (LAGE) meal (15.100 vs. 2.750 kU AGE) were studied in a randomized, cross-over, investigator-blinded design. Measurements were performed after an overnight fast, at baseline (B) and at 2, 4, and 6 h after the HAGE or LAGE meals. Both meals had the same ingredients and differed only by the cooking method. Two h following HAGE, a significant decrease from baseline occurred in adiponectin (-10%*double dagger vs. +0%) and leptin (-22%*double dagger vs. -13%*), and a significant increase occurred in vascular cell adhesion molecule 1 (+19%*double dagger vs. -5%) and thiobarbituric acid reactive substances (+23%*double dagger vs. +6%). These changes did not occur, or occurred to a lesser extent, following LAGE. At 4 h following HAGE, an increase in methylglyoxal (+20%double dagger vs. -5%) and E-selectin (+54%*double dagger vs. -3%) occurred. Urinary AGEs increased only after HAGE (+51%*double dagger vs. -2%; values presented as HAGE vs. LAGE; *P < 0.05 vs. baseline, double daggerP < 0.05 vs. LAGE). The postprandial excursions in glucose, insulin, and triglycerides were similar between both meals. A meal rich in AGEs induces acute endothelial and adipocyte dysfunction. These effects were prevented by changing the cooking method.

Topics: Adipokines; Adiponectin; Adult; Age of Onset; Aged; Diabetes Mellitus, Type 2; Diet; E-Selectin; Endothelium, Vascular; Female; Glycation End Products, Advanced; Humans; Inpatients; Leptin; Male; Middle Aged; Oxidative Stress; Thiobarbituric Acid Reactive Substances; Tyrosine

Recent studies suggest that adipose tissue hormone, leptin, is involved in the pathogenesis of arterial hypertension. However, the mechanism of hypertensive effect of leptin is incompletely understood. We investigated whether antioxidant treatment could prevent leptin-induced hypertension. Hyperleptinemia was induced in male Wistar rats by administration of exogenous leptin (0.25 mg/kg twice daily s.c. for 7 days) and separate groups were simultaneously treated with superoxide scavenger, tempol, or NAD(P)H oxidase inhibitor, apocynin (2 mM in the drinking water). After 7 days, systolic blood pressure was 20.6% higher in leptin-treated than in control animals. Both tempol and apocynin prevented leptin-induced increase in blood pressure. Plasma concentration and urinary excretion of 8-isoprostanes increased in leptin-treated rats by 66.9% and 67.7%, respectively. The level of lipid peroxidation products, malonyldialdehyde + 4-hydroxyalkenals (MDA+4-HNE), was 60.3% higher in the renal cortex and 48.1% higher in the renal medulla of leptin-treated animals. Aconitase activity decreased in these regions of the kidney following leptin administration by 44.8% and 45.1%, respectively. Leptin increased nitrotyrosine concentration in plasma and renal tissue. Urinary excretion of nitric oxide metabolites (NO(x)) was 57.4% lower and cyclic GMP excretion was 32.0% lower in leptin-treated than in control group. Leptin decreased absolute and fractional sodium excretion by 44.5% and 44.7%, respectively. Co-treatment with either tempol or apocynin normalized 8-isoprostanes, MDA+4-HNE, aconitase activity, nitrotyrosine, as well as urinary excretion of NO(x), cGMP and sodium in rats receiving leptin. These results indicate that oxidative stress-induced NO deficiency is involved in the pathogenesis of leptin-induced hypertension.

Topics: Acetophenones; Aconitate Hydratase; Aldehydes; Animals; Antioxidants; Blood Pressure; Body Weight; Creatine; Cyclic GMP; Cyclic N-Oxides; Drinking; Eating; Hypertension; Isoprostanes; Kidney; Leptin; Male; Malondialdehyde; Natriuresis; Nitric Oxide; Rats; Rats, Wistar; Reactive Nitrogen Species; Sodium; Spin Labels; Tyrosine