Fluorescent molecular peroxidation products: a prognostic biomarker of early neurologic deterioration after thrombolysis.

BACKGROUND AND PURPOSE: Fluorescent molecular peroxidation products (FMPPs) are considered potential markers of molecular oxidative damage and may provoke increased permeability and disruption of the blood-brain barrier. This study aimed to determine the value of FMPPs as a biomarker to predict neurological worsening related to early hemorrhagic transformation. METHODS: Baseline FMPP levels were measured in 186 consecutive acute ischemic stroke patients before tissue plasminogen activator treatment was administered. A serial FMPP profile (baseline before tissue plasminogen activator treatment, and 1, 2, 12, and 24 hours from treatment) was determined in a subset of 100 patients. Computed tomographic scans were performed at admission and repeated at 24 to 48 hours or after neurological worsening occurred. Symptomatic intracranial hemorrhage was defined as blood at any site in the brain associated with neurological deterioration. RESULTS: Patients who worsened had higher median FMPP levels compared with those who did not (59.68 [48.63-85.73] versus 44.87 [36.37-58.90] Uf/mL; P=0.035) at baseline. After logistic regression multivariate analysis, FMPP >48.2 Uf/mL together with age, hypertension, and systolic blood pressure remained baseline predictors of worsening at 48 hours. Moreover, baseline FMPP determination helped to distinguish between patients who worsened and those who did not (Integrated Discrimination Improvement index, 5.7%; P=0.0004). Finally, within patients who had worsened at 48 hours, those with symptomatic intracranial hemorrhage had higher FMPP levels (P=0.038). CONCLUSIONS: FMPPs might be a valuable biomarker of poor early neurological outcome and be related to the appearance of symptomatic intracranial hemorrhage in tissue plasminogen activator-treated patients, one of the most feared neurological complications after thrombolytic treatment of acute ischemic stroke.

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.

Oxidative stress in childhood type 1 diabetes: Results from a study covering the first 20 years of evolution.

This study aimed to further analyse the potential role of oxidative stress in children and adolescents with type 1 diabetes at clinical onset, during disease progression and when early microvascular complications ( + DC) appeared. Compared with age-matched controls, diabetic patients had greater oxidative damage to lipids, proteins and DNA demonstrated by analysis of plasma and erythrocyte malondialdehyde, carbonyl proteins and leukocyte 8-hydroxy-deoxyguanosine, all of which were significantly raised at onset, decreased during the first 1.5 years of evolution and rose progressively thereafter. Plasma lipid levels were significantly associated with lipid and protein oxidation products. Erythrocyte glutathione and glutathione-peroxidase activity were significantly decreased with the lowest values at onset and in + DC sub-groups. Insulin therapy in the first year improved metabolic and oxidant-antioxidant status and, consequently, hyperglycaemia-derived biomolecular oxidative damage. Diabetes-associated hyperlipidaemia is related to lipid and protein oxidation, thereby supporting the concept of glucotoxicity and lipotoxicity being inter-related. The overall increase in lipid, protein and DNA oxidative damage in diabetic patients with microangiopathy could be pathogenetically relevant in the early development of diabetes-related complications.

Placental angiogenic growth factors and uterine artery Doppler findings for characterization of different subsets in preeclampsia and in isolated intrauterine growth restriction.

OBJECTIVE: The purpose of this study was to evaluate possible relationships between placental markers and endothelial dysfunction in preeclampsia and intrauterine growth restriction. STUDY DESIGN: A prospective study was conducted in 76 patients with preeclampsia and 37 patients with intrauterine growth restriction that were classified as early onset (<34 weeks of gestational age) or late onset, and 40 control subjects. Plasma levels of placental growth factor, soluble fms-like tyrosine kinase-1, vascular cell adhesion molecule-1, and uterine artery Doppler indices were measured. RESULTS: In early-onset preeclampsia and intrauterine growth restriction, placental growth factor was lower and soluble fms-like tyrosine kinase-1 and vascular cell adhesion molecule-1 higher than in control subjects, although all changes were more pronounced in preeclampsia. In late-onset preeclampsia, those patients with abnormal uterine artery Doppler indices had higher soluble fms-like tyrosine kinase-1 and vascular cell adhesion molecule-1 levels. CONCLUSION: Biochemical changes in early-onset preeclampsia and intrauterine growth restriction point to a common placental disorder and a state of endothelial dysfunction, which may require interaction with other factors to explain the maternal disease in preeclampsia. Data in late-onset preeclampsia suggest that a proportion of them may occur with minimal placental involvement.

Atherogenic lipoprotein subfraction profile in preeclamptic women with and without high triglycerides: different pathophysiologic subsets in preeclampsia.

Abnormal lipid metabolism has been proposed as a pathogenic factor of preeclampsia, although whether it is a constant feature in all preeclamptic patients is unclear. We assessed whether plasma triglyceride (TG) levels can distinguish a subgroup of preeclamptic women with alterations in lipoprotein profile from those with normal lipid metabolism and can be used to identify 2 distinct pathogenic groups in preeclampsia. This prospective study included 34 women with preeclampsia and 23 healthy pregnant women. Preeclamptic women were further subclassified into normal-TG (<250 mg/dL) and high-TG (>or=250 mg/dL) groups on the basis of the 90th percentile in our population. Low-density lipoproteins (LDLs) were ultracentrifuged and were separated into 4 subfractions, and lipid distribution in the subfractions was analyzed in all study groups. Vascular cell adhesion molecule-1 was also measured as a marker of endothelial dysfunction. Sixteen women with preeclampsia had high TGs (47% vs 13% in control subjects, P<.001). This subgroup showed a significant shift in lipid distribution, mainly, TGs, toward the small, dense LDL subfractions. However, preeclamptic patients in the normal-TG subgroup showed LDL subfraction lipid distribution similar to that of healthy pregnancies. Vascular cell adhesion molecule-1 levels were significantly elevated in preeclamptic patients in comparison with those in control subjects regardless of TG levels. The presence of a proatherogenic lipoprotein profile, previously described in preeclampsia, is characterized by increased small dense LDL and is exclusive to a subset of preeclamptic patients with high TG levels. These findings support the concept of heterogeneous pathogenic lines in preeclampsia and the use of subclassifications in pathophysiologic research on this condition.

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 alpha-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 (alpha-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 microM; er-MDA: 7.2+/-0.7 nmol/g Hb) compared with controls (p-MDA:0.86+/-0.09 microM; 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.

A comprehensive study of oxidative stress and antioxidant status in preeclampsia and normal pregnancy.

Oxidative stress has been increasingly postulated as a major contributor to endothelial dysfunction in preeclampsia (PE), although evidence supporting this hypothesis remains inconsistent. This study aimed to analyze in depth the potential role of oxidative stress as a mechanism underlying endothelial damage in PE and the pregnant woman's susceptibility to the disease. To this end, indicative markers of lipoperoxidation and protein oxidation and changes in antioxidant defense systems were measured in blood samples from 53 women with PE and 30 healthy pregnant controls. Results, analyzed in relation to disease severity, showed PE women, compared with women with normal pregnancy, to have: (1) significantly enhanced antioxidant enzyme SOD and GPx activities in erythrocytes; (2) similar plasma alpha-tocopherol levels and significantly increased alpha-tocopherol/lipids in both mild and severe PE; (3) significantly decreased plasma vitamin C and protein thiol levels; (4) similar erythrocyte glutathione content, total plasma antioxidant capacity, and whole plasma oxidizability values; (5) significantly elevated plasma total lipid hydroperoxides, the major initial reaction products of lipid peroxidation, in severe PE; (6) no intracellular or extracellular increases in any of the secondary end-products of lipid peroxidation, malondialdehyde or lipoperoxides; (7) similar oxidative damage to proteins quantified by plasma carbonyl levels, immunoblot analysis, and advanced oxidation protein products assessment; and (8) significantly elevated and severity-related soluble vascular cell adhesion molecule-1 serum levels reflecting endothelial dysfunction. No correlations were found among plasma levels of circulating adhesion molecules with regard to lipid and protein oxidation markers. Globally, these data reflect mild oxidative stress in blood of preeclamptic women, as oxidative processes seem to be counteracted by the physiologic activation of antioxidant enzymes and by the high plasma vitamin E levels that would prevent further oxidative damage. These results do not permit us to conclude that oxidative stress might be a pathogenetically relevant process causally contributing to the disease.

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 alpha-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.

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.