Carmen Domínguez

BIOMARKERS OF DIABETES-ASSOCIATED OXIDATIVE STRESS AND ANTIOXIDANT STATUS IN YOUNG DIABETIC PATIENTS WITH OR WITHOUT SUBCLINICAL COMPLICATIONS

The aims of the study were to ascertain the potential role of oxidative stress in the onset of disease-related pathophysiological complications in young type 1 diabetes patients. Indicative parameters of lipoperoxidation, protein oxidation, and changes in antioxidant defense system status were measured in blood samples from 26 young diabetic patients with recently diagnosed (< 6 months) microangiopathy (+DC), 28 diabetic patients without complications (-DC), and 40 healthy age-matched controls (CR). Both diabetic groups presented similar fructosamine and glycated hemoglobin (HbA1c) values. Results showed erythrocyte glutathione peroxidase activity, glutathione content, and plasma beta-carotene to be significantly lower in diabetic patients compared with control subjects, but with no significant differences between -DC and +DC groups. Antioxidant enzyme superoxide dismutase activity was significantly higher in the erythrocytes of diabetic patients independently of the presence of microvascular complications. However, the plasma alpha-tocopherol/total lipids ratio was significantly diminished in +DC group compared with -DC (p =.008). Lipid peroxidation indices measured in plasma included malondialdehyde, lipid hydroperoxides, and lipoperoxides, which were significantly elevated in our diabetic patients regardless of the presence of complications. Evidence of oxidative damage to proteins was shown both through the quantification of plasma protein carbonyl levels, which were significantly higher in -DC (0.61 +/- 0.09 mmol/mg prot), and higher still in the +DC patients (0.75 +/- 0.09 mmol/mg prot) compared with those of controls (0.32 +/- 0.03 mmol/mg prot; p <.01) and immunoblot analysis of protein-bound carbonyls. Additionally, a marked increase in protein oxidation was observed in +DC patients through assessment of advanced oxidation protein products (AOPP) considered to be an oxidized albumin index; AOPP values were significantly higher in +DC than in -DC patients (p <.01) and CR (p <.0001). These results point to oxidatively modified proteins as a differential factor possibly related to the pathogenesis of diabetic complications.

Oxidative Stress at Onset and in Early Stages of Type 1 Diabetes in Children and Adolescents

OBJECTIVE In diabetes, the persistence of hyperglycemia has been reported to cause increased production of oxygen free radicals through glucose autooxidation and nonenzymatic glycation. The aim of this study was to determine whether oxidative cellular damage occurs at the clinical onset of diabetes and in later stages of the disease in young patients. RESEARCH DESIGN AND METHODS Indicative parameters of lipoperoxidation, protein oxidation, and changes in the status of antioxidant defense systems were evaluated in single blood samples from 54 diabetic children, adolescents, and young adults and 60 healthy age- and sex-matched control subjects. RESULTS Malondialdehyde and protein carbonyl group levels in plasma were progressively higher in diabetic children and adolescents than in control subjects (P < 0.0001). The highest erythrocyte superoxide dismutase (SOD) activity was found in diabetic children at onset of clinical diabetes. In diabetic adolescents, SOD was also significantly higher (P < 0.0001) than in control subjects. Erythrocyte glutathione peroxidase was significantly lower in diabetic children and adolescents compared with control subjects (P < 0.002). A significant decline in blood glutathione content at the recent onset of diabetes was found (P < 0.0001). Furthermore, our results demonstrated progressive glutathione depletion during diabetes evolution. The plasma α-tocopherol/total lipids ratio and β-carotene levels during diabetes development (P < 0.001) were low. CONCLUSIONS This cross-sectional study in young diabetic patients showed that systemic oxidative stress is present upon early onset of type 1 diabetes and is increased by early adulthood. Decreased antioxidant defenses may increase the susceptibility of diabetic patients to oxidative injury. Appropriate support for enhancing antioxidant supply in these young diabetic patients may help prevent clinical complications during the course of the disease.

Predictive value of angiogenic factors and uterine artery Doppler for early- versus late-onset pre-eclampsia and intrauterine growth restriction

To investigate potential differences in the prediction of early‐ vs. late‐onset pre‐eclampsia and/or intrauterine growth restriction (PE/IUGR) by second‐trimester uterine artery Doppler examination, and measurement of maternal serum placental growth factor (PlGF) and soluble fms‐like tyrosine kinase 1 (sFlt1).

Oxidative Stress After Thrombolysis-Induced Reperfusion in Human Stroke

Background and Purpose— Animal models of transient ischemia suggest that oxygen-derived free radicals produced on reperfusion of ischemic brain could constitute the main cause of reperfusion injury. We aimed to determine the presence and role of lipid peroxidation and protein oxidation–related molecules after tissue plasminogen activator–induced recanalization in human stroke. Methods— A total of 160 patients with strokes involving the middle cerebral artery and treated with tissue plasminogen activator and 60 healthy controls were included. Blood samples, transcranial Doppler recordings, and National Institutes of Health Stroke Scale scores were obtained at baseline (pretreatment), 1 hour and 2 hours after tissue plasminogen activator bolus, and 12 hours and 24 hours after stroke onset. The main lipid peroxidation end-product malondialdehyde, advanced oxidation protein products, and plasma concentrations of myeloperoxidase were assessed. Results— At baseline, all oxidative stress biomarkers were higher than in control subjects (P<0.01 for all comparisons). Malondialdehyde remained high compared with controls during the study period, whereas myeloperoxidase concentrations were significantly raised at baseline, 1 hour after tissue plasminogen activator administration, and 12 hours after stroke onset. Malondialdehyde concentrations correlated with stroke severity and were associated with outcome and with hemorrhagic complications. Regarding recanalization, among those patients with middle cerebral artery recanalization by the end of tissue plasminogen activator infusion (44%) or anytime thereafter, no peaking of any of the studied molecules could be identified. Conclusions— Our study showed that systemic oxidative damage to lipids and proteins had already occurred at baseline in stroke. In contrast to animal studies, a relationship between free radical–mediated oxidative damage to lipids or proteins and reperfusion injury after arterial recanalization could not be established.

First trimester screening for early and late preeclampsia based on maternal characteristics, biophysical parameters, and angiogenic factors.

The aim of this article is to develop the best first‐trimester screening model for preeclampsia (PE) based on maternal characteristics, biophysical parameters, and angiogenic factors in a low‐risk population.

Plasma VAP-1/SSAO activity predicts intracranial hemorrhages and adverse neurological outcome after tissue plasminogen activator treatment in stroke.

Background and Purpose— Vascular adhesion protein-1 (VAP-1) is a cell surface and circulating enzyme involved in recruitment of lymphocytes and neutrophils through its semicarbazide-sensitive amine oxidase (SSAO) activity. We aimed to study plasma VAP-1/SSAO activity in relation to the risk for intracranial bleeding complications in patients with stroke treated with tissue plasminogen activator (tPA), the greatest safety concern with this treatment. Methods— In 141 patients with ischemic stroke, we measured VAP-1/SSAO activity in plasma taken before tPA administration. Hemorrhagic events were classified according to brain CT criteria and functional outcomes evaluated using the National Institutes of Health Stroke Scale. We also assessed the potential therapeutic effect of blocking VAP-1/SSAO activity in a rat embolic stroke model treated with tPA. Results— We saw significantly higher levels of plasma VAP-1/SSAO activity in patients who subsequently experienced hemorrhagic transformation. Elevated plasma VAP-1/SSAO activity also predicted worse neurological outcome in these patients. In the rat model, we confirmed that use of the inhibitor semicarbazide prevented adverse effects caused by delayed tPA administration, leading to a smaller infarct volume. Conclusions— Our data demonstrate that baseline VAP-1/SSAO activity predicts parenchymal hemorrhage after tPA, suggesting the safety of thrombolytic agents could be improved by considering VAP-1/SSAO activity. Furthermore, anti-VAP-1/SSAO drugs given with tPA may prevent neurological worsening in patients with ischemic stroke.

Estimation of lipoperoxidative damage and antioxidant status in diabetic children: Relationship with individual antioxidants

Increased oxidative stress has emerged as a potential mechanism implicated in the pathogenesis, progression and cell dysfunction associated with many diseases including diabetes. In routine clinical practice, the estimation of the degree of oxidative damage and antioxidant status, even in paediatric patients, by appropriate techniques appears to be of interest. The aim of this study was to reliably identify patients with increased oxidant stress and/or reduced antioxidant defence mechanisms with a small blood sample and verify the applicability to the study of diabetic children (DC) at clinical onset of the disease. In 1-ml blood samples from 30 DC and 34 controls, techniques for accurately measuring malondialdehyde (MDA) concentrations in plasma and erythrocytes (using HPLC analysis with fluorometric detection), total radical antioxidant potential (TRAP) and blood plasma oxidizability were adapted and validated. Plasma α-tocopherol (HPLC), uric acid and sulfhydryl (SH) groups were also determined. At clinical onset of diabetes a significant reduction in plasma TRAP values (P<0.01) was observed in DC compared with controls. Similarly, a significant fall in individual antioxidant levels (α-tocopherol/total lipids, uric acid and protein SH) was noted in plasma of DC. Highly significant increases were found in both plasma and erythrocyte MDA levels in DC (p-MDA:1.7±0.2 μM; er-MDA: 7.2±0.7 nmol/g Hb) compared with controls (p-MDA:0.86±0.09 μM; P<0.0003; er-MDA:3.8±0.2 nmol/g Hb, P<0.0001). Plasma MDA and triglyceride levels correlated directly only in DC (P<0.001). Whole plasma oxidizability was significantly higher in DC than in controls (P<0.0001) and this parameter correlated significantly with plasma cholesterol and triglyceride concentrations (P<0.0001). The micromethods adapted and applied to the simultaneous detection of lipid peroxidation products and antioxidant status permit accurate and reliable assessment of the oxidative stress process in small plasma samples. Our results clearly show systemic peroxidative damage associated with insufficient defence mechanisms against ROS to be already present at clinical onset of type 1 diabetes mellitus in children and adolescents.

Amniotic fluid glucose and cytokines values in the early diagnosis of amniotic infection in patients with preterm labor and intact membranes.

OBJECTIVE Our goal was to compare sensitivity, specificity, and predictive values of glucose and cytokines [interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor (TNF)] in amniotic fluid (AF) to detect an AF-positive culture. METHODS Amniocentesis was performed on 113 patients with preterm labour (PTL) and intact membranes. Fluid was cultured for aerobic and anaerobic bacteria, and for mycoplasmas. AF analysis included cytokines and glucose determinations. RESULTS The prevalence of positive AF cultures was 11.5% (13/113). Anaerobic bacteria were isolated in 9 patients (69.2%). The glucose <16 mg/dl and cytokines values; IL-1 >640 pg/ml, IL-6 >55,000 pg/ml, IL-8 >1,000 pg/ml, TNF >672 pg/ml, were significantly correlated (P < 0.01) with AF culture result. Glucose had a sensitivity of 69.2% and a specificity of 96% for the prediction of positive AF culture. The sensitivity and specificity of the cytokines ranged from 61.5-53.4% and 79.8-8.99%, respectively. CONCLUSIONS In the diagnosis of the AF-positive culture, glucose <16 mg/dl is more sensitive than cytokines.

Nitric oxide protects against pancreatic subcellular damage in acute pancreatitis.

Objectives Oxidative stress involvement in damage to the pancreas in acute pancreatitis (AP) is well documented. However, little is known about oxidative damage occurring in the different subcellular fractions of pancreatic cells. The aim of this study was to ascertain the main targets of oxidative damage inside cells after AP and the role of endogenous nitric oxide (NO) in it. Methods A model of cerulein-induced AP in rats was used and N-nitro-l-arginine methyl ester (l-NAME) was administered as an NO production inhibitor. After pancreatitis induction, indicative parameters of lipid peroxidation and protein oxidation together with some enzymatic and nonenzymatic endogenous free radical scavengers were assessed in serum and pancreatic subcellular fractions. Conclusions In pancreatitic rats, malondialdehyde and protein carbonyl group concentrations were significantly increased (P < 0.05) in serum and some fractions. The increases were higher in l-NAME-treated rats (P < 0.05). Superoxide dismutase and catalase activities were also increased (P < 0.05) but were decreased (P < 0.05) with l-NAME. The &agr;-tocopherol concentration diminished (P < 0.05) in serum and all the studied subcellular fractions and the decrease was stronger in l-NAME-treated rats. Our data suggest that microsomes followed by lysosomal + mitochondrial are the fractions most susceptible to oxidative damage in AP. Endogenous NO plays a protective role against oxidative damage to subcellular fractions.

Angiogenic and antiangiogenic factors before and after resolution of maternal mirror syndrome

Mirror syndrome is a rare condition that involves fetal hydrops, placentomegaly and severe maternal edema. The pathogenesis of this syndrome mimics endothelial dysfunction observed in pre‐eclampsia. We report a case of maternal mirror syndrome caused by bilateral fetal hydrothorax that resolved after intrauterine pleuroamniotic shunt placement. At the time of the clinical manifestation there was an antiangiogenic state similar to that seen in pre‐eclampsia, which resolved after fetal treatment. Our findings suggest that mirror syndrome is a manifestation of a broad spectrum of pathological conditions that induces an antiangiogenic state. Copyright