Increased systemic and peritoneal oxidative stress biomarkers in endometriosis are not related to retrograde menstruation.

Objetives: The goal of this study was to determine if systemic and peritoneal oxidative stress biomarkers are related to each other and to retrograde menstruation in endometriosis. Methods: Plasma and peritoneal fluid oxidative stress biomarkers and hemoglobin and erythrocytes in peritoneal fluid as retrograde menstruation indicators, were measured in 28 patients with endometriosis and 23 without endometriosis. Results: In the peritoneal fluid, carbonyls and lipohydroperoxides, indicative of protein and lipid oxidative damage, were higher in endometriosis group (21%, p = 0.016 and 46%, p = 0.009, respectively). However, these biomarkers were not different in the blood plasma of both groups, and only protein dityrosine, was increased in the plasma of endometriosis group (31%, p = 0.04). The peritoneal fluid hemoglobin content was not higher in the endometriosis group, nor related to carbonyls and lipohydroperoxides. Additionally, the peritoneal fluid oxidative biomarkers were not correlated with the blood plasma ones, and only malondialdehyde, and ischemia-modified albumin were almost two times higher in peritoneal fluid. Discussion: Our results show a peritoneal and systemic oxidative stress biomarkers increase in endometriosis, but not related to each other, and do not support the hypothesis of an increase in hemoglobin-iron supply towards the peritoneal cavity that causes oxidative damage.

A randomized controlled trial comparing isosorbide dinitrate-oxytocin versus misoprostol-oxytocin at management of foetal intrauterine death.

BACKGROUND: The metabolic activity of endogenous nitric oxide (NO) and the medical use of nitrovasodilatory drugs like isosorbide dinitrate have been shown to be potential inducers inducers of cervical ripening prior to surgical evacuation of the uterus. OBJECTIVE: To assess the therapeutic efficacy and safety of combined isosorbide dinitrate-oxytocin in the management of intrauterine foetal death (IUFD). METHODS: Sixty women with IUFD after 20 weeks of gestation requesting uterine evacuation were randomly selected to receive isosorbide dinitrate gel solution (80 mg/1.5 mL; n = 30) or misoprostol gel solution (100 mcg/1.5 mL; n = 30) every 3 h with a maximum of four doses or until a Bishop score >7 was reached. Subsequently, patients received a high dose of intravenous oxytocin until complete uterus evacuation was achieved. Therapeutic efficacy was evaluated by mean the relative risk of the foetal expulsion based on comparison of event rates, and the proportion of women induced to labor at 7, 10 and 15 h after the administration of isosorbide dinitrate or misoprostol. Safety was assessed on the basis of woman´s vital signs and evaluation of adverse effects, including headache, abdominal pain, pelvic pain, lower back pain, nausea, dizziness and vomiting. RESULTS: The foetal expulsion rate using the isosorbide dinitrate-oxytocin combination was approximately 4.4 times, and at least 2.1 times, the foetal expulsion rate with the misoprostol-oxytocin regimen at any given point in time. The proportion of women achieved vaginal delivery at 15 hours was 100% for the isosorbide dinitrate-oxytocin group and 86.7% for the misoprostol-oxytocin group. The average delivery induction interval was significantly lower when isosorbide dinitrate-oxytocin was used (8.7 ± 3.1 h) than when misoprostol-oxytocin (11.9 ± 3.1 h) was used. A total of 20% of patients in the isosorbide dinitrate-oxytocin group recorded headache, and no cases of uterine tachysystole, haemorrhage or coagulopathy were recorded. CONCLUSION: This study indicates that intravaginal isosorbide dinitrate followed by intravenous oxytocin was more effective than the conventional method used to induce labour in the medical management of foetal death in pregnancies after 20 weeks of gestation. TRIAL REGISTRATION: Clinicaltrials.gov NCT02488642.

Peroxynitrite activates glucose uptake in 3T3-L1 adipocytes through a PI3-K-dependent mechanism.

Peroxynitrite, the product of the reaction between *NO and O2*-, is a strong oxidant and nitrating molecule, and it has been recently consideredas a component of some important signaling pathways. Herein, we report the effect of peroxynitrite on glucose uptake in 3T3-L1 adipocytes. Peroxynitrite stimulated glucose uptake and this effect was inhibited by citochalasin B, indicating the participation of facilitated GLUT transporters. Peroxynitrite-induced glucose uptake was not related to intracellular ATP, nor to external or internal calcium, but it was inhibited by the phosphatidylinositol 3-kinase (PI3-K) inhibitor, wortmannin. Additionally, we also found that peroxynitrite did not activate the insulin receptor nor the PI3-K downstream signaling protein kinase B (PKB/Akt). The dose-dependent inhibitory action of wortmannin suggests that peroxynitrite activates glucose transport without affecting GLUT transporters translocation.

Reactive oxygen species (ROS) induce chemical and structural changes on human insulin in vitro, including alterations in its immunoreactivity.

Oxidative stress occurs when the production of reactive oxygen species (ROS) exceeds the endogenous antioxidant defense. Peroxidations induced by ROS are the key of chemical and structural modifications of biomolecules including circulating proteins. To elucidate the effect of ROS on circulating proteins and considering the presence of oxidative stress in Diabetes Mellitus, the effects of ROS, in vitro, on human insulin were studied. We utilized the Fenton reaction for free hydroxyl radical (HO*) generation in presence of human recombinant insulin measuring chemical changes on its molecular structure. The induced changes in insulin were: a) significant increase on absorbance (280 nm) due to phenylalanine hydroxylation (0.023 +/- 0.007 to 0.13 +/- 0.07). b) Peroxidation products formed on amino acids side branches (peroxyl and alcohoxyl group); measured as increased capacity of reduce nitroblue of tetrazolium (NBT) to formazan (0.007 +/- 0.007 to 0.06 +/- 0.02). c) Increased concentration of free carbonyl groups (8.8 +/- 8.7 to 45.6 +/- 20.2 pmoles dinitrophenylhidrazones/nmol insulin) with lost of secondary structure, and d) Modification of epithopes decreasing the insulin antigen-antibody reactivity measured as a decrease in insulin concentration by RIA. In conclusion, the radical hydroxyl in vitro is able to induce molecular modifications on insulin.

Oxidation by reactive oxygen species (ROS) alters the structure of human insulin and decreases the insulin-dependent D-glucose-C14 utilization by human adipose tissue.

The formation of dityrosine of human insulin oxidized by metal-catalyzed oxidation system (H2O2/Cu) was estimated by fluorescent methods. The oxidation of tyrosine and phenylalanine residues present on the insulin molecule was evident after 2 minutes of in vitro oxidation due to the formation of protein-bound dityrosine. The success of oxidative protein modification was followed until available aromatic residues were consumed (60 minutes), measured by their emission at 405 nm. The structural and chemical changes on insulin molecule are related to the loss of biological activity as assessed by measuring the increase of U-14C-glucose utilization by human adipose tissue in a radiorespirometry system. The oxidation of glucose (14CO2 production) of the adipose cells was increased 35 % (301 +/- 119 to 407 +/- 182 cpm/mg in dry weight. P < 0.05) in presence of 0.1 IU and 69 % (301 +/- 119 to 510 +/- 266 cpm/dry weight. P < 0.05) for 1.0 IU of insulin. The recombinant human insulin oxidized for 5 minutes only increased the glucose oxidation by 25 %. In conclusion, these observations show that dityrosine formation and other oxidative chemical changes of insulin due to its in vitro oxidation decrease and can abolish its biological activity.

Urban PM2.5 activates GAPDH and induces RBC damage in COPD patients.

During Chronic Obstructive Pulmonary Disease (COPD) progression, the intracellular antioxidant defence in RBCs must preserve the integrity of the plasmalemma through NADPH+ generation to obtain a sufficient number of reduced non-protein SH-groups. Here, we studied the activities of enzymes in RBCs that are related to glutathione metabolism under conditions of increasing oxidative stress, which are associated with COPD progression, by increasing cellular damage in vitro with PM2.5, a ROS generator. The study included 43 patients, who were separated according to their GOLD classification into moderate and severe groups, along with 11 healthy volunteers (HV). Blood samples were analysed for G6PD, GAPDH, GPx, and GR. The results showed significant decreases in the oxidation of the G6PD, GR and GPx proteins, resulting in decreased enzymatic activity. By contrast, an increase (p<0.05) in GAPDH was observed, suggesting a pool of ATP on the membrane. However, it is evident that RBCs are damaged during the progression of COPD, although their integrity is preserved, and they retain limited function, thus allowing patient survival without haemolysis.

Urban PM2.5 induces ROS generation and RBC damage in COPD patients.

Particulate matters (PM) produce adverse effects on the respiratory system and cause COPD. These effects are thought to involve intrinsic generation of ROS which are present in ambient PM (transition metals and aromatic organic compounds). Here, we examined the chemical composition and ultra-microscopic structure of PM2.5. The effect of this PM was studied in red blood cell (RBC) membranes (ghosts) from healthy volunteers (n = 11) and COPD patients (n = 43). These effects were compared with that produced by a Fenton metal-catalytic ROS generator. Oxidative biomarkers and cell damage were singificantly increased in presence of PM2.5 or ROS generator in RBC of COPD patients as compared with those in cells from healthy volunteers. In contrast, total SH groups, band 3 phospho-tyrosine phosphatase (PTPase) and glucose-6 phosphate dehydrogenase (G6PD) activities were all diminished in cells from COPD patients. In conclusion, PM2.5 increases damage to RBCs from COPD patients, decreases the activity of PTPase and G6PD, and alters the function of the anionic exchanger (AE1) and the antioxidant response by decreasing SH groups.

Structural and functional changes in the insulin molecule produced by oxidative stress.

The change produced by oxidative stress on proteins (cross-links, backbone cleavage, amino acid modification) generates structural changes with a wide range of consequences such as increased propensity to the aggregation or proteolysis, altered immunogenicity and frequently enzymatic and binding inhibition. Insulin is particularly sensitive to conformational changes, aggregation and cross-linking; any change on insulin could impair its function. We have examined the biological activity of insulin modified by hydroxyl radical and exposed to acrolein in rats and adiposites. We found out important changes that we have shown as prototype of possible effect of oxidative stress on the structural and functional damage to insulin. Whereas, hydroxyl radical and acrolein both have diminished the hypoglycemic effect of insulin in vivo, and the effect of acrolein seems be to involved in carbonylation and not derived from inter-molecular cross-links formation or aggregates. The effect was highly stimulated at alkaline pH, concomitant with carbonyl formation and then probably aldolic condensation type reaction-dependent. Hydroxyls radical generates tyrosine derivative formation and introduces non aldehyde dependent carbonyls in the insulin molecule.

Formation of an adduct between insulin and the toxic lipoperoxidation product acrolein decreases both the hypoglycemic effect of the hormone in rat and glucose uptake in 3T3 adipocytes.

Lipid peroxidation induced by reactive oxygen species might modify circulating biomolecules because of the formation of alpha,beta-unsaturated or dicarbonylic aldehydes. In order to investigate the interaction between a lipoperoxidation product, acrolein, and a circulating protein, insulin, the acrolein-insulin adduct was obtained. To characterize the adduct, gel filtration chromatography, sodium dodecylsulfate-polyacrylamide gel electrophoresis and carbonyl determination were performed. Induction of hypoglycemia in the rat and stimulation of glucose uptake by 3T3 adipocytes were used to evaluate the biological efficiency of the adduct compared with that of native insulin (Mackness, B., Quarck, R., Verte, W., Mackness, M., and Holvoet, P. (2006) Arterioscler., Thromb. Vasc. Biol. 26, 1545-1550). Formation of the acrolein-insulin complex in vitro increased the carbonyl group concentration from 2.5 to 22.5 nmol/mg of protein, and it formed without intermolecular aggregates (Halliwell, B., and Whiteman, M. (2004) Br. J. Pharmacol. 142, 231-255. The hypoglycaemic effect 18 min after administration to the rat is decreased by 25% (Robertson, R. P. (2004) J. Biol. Chem. 279, 42351-42354. An adduct concentration of 94 nM, compared to 10 nM for native insulin, was required to obtain the A 50% (concentration needed to obtain 50% of maximum transport of glucose uptake by 3T3 adipocytes). In conclusion, formation of the acrolein-insulin adduct modifies the structure of insulin and decreases its hypoglycemic effect in rat and glucose uptake by 3T3 adipocytes. These results help explain how a toxic aldehyde prone to be produced in vivo can structurally modify insulin and change its biological action.

La función plaquetaria más allá de la hemostasis: participación en las enfermedades respiratorias / Platelet function beyond haemostasis: Role in respiratory diseases

Actualmente se sabe que las plaquetas, además de almacenar diversos mediadores químicos, también tienen la capacidad de realizar síntesis de varios tipos de proteínas a partir de ARN preformados y de interaccionar con diversos tipos de partículas, con componentes de la matriz extracelular y con varios tipos celulares. Estas características posibilitan que las plaquetas intervengan activamente, no sólo en la hemostasis y trombosis, sino también en la inflamación, remodelación tisular y posiblemente en la defensa innata.

Platelets store different chemical mediators and synthetize various types of proteins from preformed RNA; they also interact with different particles, components of the extracellular matrix and with different kinds of cells. This characteristics enable platelets to have important roles In hemostasis, thrombosis, inflammation, tissue remodeling and possibly in mechanisms of innate defense.

Sistemas moleculares en la interacciones celulares: II. Iimplantación embrionaria en mamíferos / Molecular systems in the cellular interactions: II. Embrionary implantation in mammals

En el presente trabajo se revisan los sistemas moleculares de reconocimiento y adhesión celulares que participan en la implantación embrionaria de los mamíferos.En el proceso de implantación embrionaria, las interacciones son compejas, ya que son diversos tipos celulares los involucrados: las células del trofoblasto del embrión interactúan con varias células uterinas y con sus respectivas matrices extracelulare; participando lactosaminoglicanos, integrinas, cadherinas y galactosil transferasas.

Participation of oxygen-free radicals in the oxido-reduction of proteins

Recent studies have focused attention on the possible role of active oxygen species on protein damage and degradation. The reactions of free radicals on biomolecules are important in physiology and pathology. A number of systems that generate free radicals catalyze the oxidative modification of proteins in two species: protein peroxides, which can consume important antioxidants; and proteinbound reducing moieties, which can reduce transition metals, and may enhace their activity in radical reactions. Protein oxidation also contributes to the pool of damaged enzymes and accumulation of abnormal and damaged proteins, which increases during aging and in various pathological states, such as atherosclerosis, cancer, etc

Participación del óxido nítrico en la función reproductora de mamíferos / Nitric oxide participation in mammals reproductive function

El óxido nítrico, es un mensajero fisiológico que participa en múltiples eventos celulares, muchos de los cuales son extensamente investigados en la actualidad. El propósito de esta revisión, es enfatizar la participación del óxido nítrico a nivel reproductivo, uno de los aspectos estudiados más recientemente, campo donde aún quedan muchas preguntas por formular

Sistemas moleculares en las interacciones celulares I: fecundación en mamíferos / Molecular systems in the cellular interactions I: fecundation in mammals

Las células de los orgnismos multicelulares requieren de diversos mecanismos de reconocimiento entre si, a fin de funcionar de manera integral. En el presente trabajo se revisan los sistemas moleculares de reconocimiento y adhesión celulares en general, y en particular aquellos que participan en la fecundación del óvulo en los mamíferos. Varias proteínas de la superficie del espermatozoide con actividad catalítica (galactosiltransferasa, proteasas y glicosidasas) o de lectinas, reconocen y unen de manera específica a componentes glicoprotéicos de la zona pelúcida del óvulo, como un requisito previo a la fecundación.