Sample entropy of laser Doppler flowmetry signals increases in patients with systemic sclerosis

Associated to reactivity tests, laser Doppler flowmetry (LDF) emphasizes abnormal skin microvascular function in diseases affecting digits, such as Raynaud\u27s phenomenon (RP) and systemic sclerosis (SSc). However, baseline perfusion value does not discriminate between disease states. We study if LDF sample entropy (SampEn) allows distinguishing healthy subjects, RP and SSc patients. LDF measurements were performed on finger pad and forearm of 108 subjects (27 controls, 28 RP patients, 53 SSc patients), before and after local thermal hyperemia. We also assessed the reproducibility of SampEn [expressed as within-subject coefficients of variation (CV) and intra-class correlation coefficients (ICC)]. Baseline SampEn is significantly increased in patients with SSc compared to RP and controls on finger pad [0.49 (0.19), 0.38 (0.14) and 0.36 (0.15), respectively; P < 0.002], but not on forearm. However, local thermal hyperemia increased SampEn at all sites and for all groups. Finally, reproducibility of SampEn computed on two baseline segments was acceptable (CV = 26%, ICC = 0.63). SampEn of skin blood flow at rest is increased on finger pad of patients with SSc but not on forearm. This is consistent with the pathophysiology of the disease, which predominantly affects digital microcirculation in most patients. SampEn of LDF signal could be a reproducible tool to predict digital microvascular impairment

Oestrogen metabolites in relation to isoprostanes as a measure of oxidative stress

Objective  Oestradiol (E2) and its metabolites 2-hydroxyoestrone (2-OHE1) and 16Α-hydroxyoestrone (16Α-OHE1) are thought to curtail the greater oxidative stress found in the development and progression of disease conditions including atherosclerosis. We related oestrogen levels to F 2a -isoprostane levels, a biomarker of oxidative stress. Design and participants  Data were obtained from 1647 women, aged 47–57 years, participating in the fifth annual follow-up of the Study of Women's Health Across the Nation (SWAN), a study of the menopausal transition. Measurements  Serum E2 and urinary 2-OHE1 and 16Α-OHE1 concentrations were determined by enzyme-linked immunosorbent assay (ELISA) and urinary F 2a -isoprostanes were measured by enzyme immunoassay (EIA). Results  F 2a -isoprostane concentrations were elevated in women who smoked, a behaviour associated with increased oxidative stress, but not in stages of the natural menopause. Mean F 2a -isoprostane concentrations among pre- and postmenopausal women who smoked were 1082 and 1064 pg/ml, respectively, values double those in pre- (343 pg/ml) and postmenopausal (379 pg/ml) nonsmoking women. 2-OHE1 and F 2a -isoprostane concentrations were positively and highly correlated (partial correlations Ρ Y|X  = 0·44 and Ρ Y|X  = 0·43 in pre- and postmenopausal women, respectively). Similarly, 16Α-OHE1 concentrations were positively and highly correlated with F 2a -isoprostane concentrations (Ρ Y|X  = 0·52 and Ρ Y|X  = 0·59 in pre- and postmenopausal women, respectively). E2 was significantly correlated with F 2a -isoprostanes only in postmenopausal women (Ρ Y|X  = 0·20). Associations were adjusted for age, body mass index (BMI), race/ethnicity, lipids, physical activity level and alcohol consumption. Conclusions  This study does not support the commonly held hypothesis that levels of endogenous E2 or its oestrone metabolites favourably modify oxidative stress by decreasing F2 a -isoprostane levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74943/1/j.1365-2265.2007.03108.x.pd

Exploring venlafaxine pharmacokinetic variability with a phenotyping approach, a multicentric french-swiss study (MARVEL study).

It is well known that the standard doses of a given drug may not have equivalent effects in all patients. To date, the management of depression remains mainly empirical and often poorly evaluated. The development of a personalized medicine in psychiatry may reduce treatment failure, intolerance or resistance, and hence the burden and costs of mood depressive disorders. The Geneva Cocktail Phenotypic approach presents several advantages including the "in vivo" measure of different cytochromes and transporter P-gp activities, their simultaneous determination in a single test, avoiding the influence of variability over time on phenotyping results, the administration of low dose substrates, a limited sampling strategy with an analytical method developed on DBS analysis. The goal of this project is to explore the relationship between the activity of drug-metabolizing enzymes (DME), assessed by a phenotypic approach, and the concentrations of Venlafaxine (VLX) + O-demethyl-venlafaxine (ODV), the efficacy and tolerance of VLX. This study is a multicentre prospective non-randomized open trial. Eligible patients present a major depressive episode, MADRS over or equal to 20, treatment with VLX regardless of the dose during at least 4 weeks. The Phenotype Visit includes VLX and ODV concentration measurement. Following the oral absorption of low doses of omeprazole, midazolam, dextromethorphan, and fexofenadine, drug metabolizing enzymes activity is assessed by specific metabolite/probe concentration ratios from a sample taken 2 h after cocktail administration for CYP2C19, CYP3A4, CYP2D6; and by the determination of the limited area under the curve from the capillary blood samples taken 2-3 and 6 h after cocktail administration for CYP2C19 and P-gp. Two follow-up visits will take place between 25 and 40 days and 50-70 days after inclusion. They include assessment of efficacy, tolerance and observance. Eleven french centres are involved in recruitment, expected to be completed within approximately 2 years with 205 patients. Metabolic ratios are determined in Geneva, Switzerland. By showing an association between drug metabolism and VLX concentrations, efficacy and tolerance, there is a hope that testing drug metabolism pathways with a phenotypical approach would help physicians in selecting and dosing antidepressants. The MARVEL study will provide an important contribution to increasing the knowledge of VLX variability and in optimizing the use of methods of personalized therapy in psychiatric settings. ClinicalTrials.gov NCT02590185 (10/27/2015). This study is currently recruiting participants

Les isoprostanes, biomarqueurs de peroxydation lipidique chez l'homme. Partie 3 : biomarqueurs et médiateurs en physiologie et pathologie vasculaire

National audienceThe 15-series F2-isoprostanes mediate vasoconstriction in different vascular beds and species. This contraction is mediated by the thromboxane receptors stimulation, and may be modulated by the endothelium. Furthermore, 15-F2t-IsoP induces smooth muscle cells mitogenesis and monocyte adhesion to endothelial cells. Some 15-series E2-isoprostanes are more potent than F2-isoprostanes. In clinical studies, 15-F2t-IsoP levels are increased in vascular disorders involving atherosclerosis, ischemia–reperfusion and inflammation. F2-isoprostane levels correlate to the severity of heart failure and pulmonary hypertension, raising the potential prognostic interest of these biomarkers. Whether the effects observed in vitro are observed consistently in vivo at physiological concentrations and whether these effects contribute to pathological states in vivo is still debated.Les F2-isoprostanes de la série 15 induisent une vasoconstriction sur la plupart des territoires vasculaires chez l'animal comme chez l'homme. Cette vasoconstriction est liée à la stimulation des récepteurs au thromboxane, et peut être modulée par l'endothélium. De plus, la 15-F2t-IsoP induit une prolifération des cellules musculaires lisses et une adhésion monocytaire sur les cellules endothéliales. Les isoprostanes E2 sont plus puissants, mais sont moins facilement détectables dans les liquides biologiques. En condition clinique, les taux d'isoprostanes sont élevés dans le cadre de certaines pathologies vasculaires impliquant l'athérosclérose, l'ischémie–reperfusion ou l'inflammation. Il existe une corrélation entre la sévérité de l'insuffisance cardiaque et de l'hypertension artérielle pulmonaire et les taux d'isoprostanes, posant la question d'un intérêt potentiel pronostique de ces biomarqueurs. Une question à résoudre est de savoir si les effets délétères observés in vitro peuvent être observés chez l'homme à des concentrations physiologiques, et de déterminer si ces effets peuvent contribuer à la physiopathologie de certaines pathologies vasculaires

Les isoprostanes, biomarqueurs de peroxydation lipidique chez l'homme. Partie 2 : méthodes de quantification

International audienceThe isoprostanes are a new class of natural products produced in vivo by a non-enzymatic free-radical-induced peroxidation of polyunsaturated fatty acids. The quantification of these compounds represents a reliable and useful index of lipid peroxidation and oxidant stress in vivo. Then, a large amount of works has been done in the field of isoprostane analysis, but till now, no standardized method seems to emerge. Indeed, described methodologies differ either in the sample preparation steps or in the detection techniques or both. Extraction and purification procedures are often critical and time-consuming, requiring successive chromatographic steps and these procedures lead to a substantial loose of target compounds. Moreover, two main analytical approaches have been adopted for IsoP measurement: immunological methods or mass spectrometry. Some discussion about the methodology used for measurement of isoprostane is important. This review will aim to present and compare different methods developed nowadays for extraction, purification and analysis of F2-iPs in various biological samples.Les isoprostanes sont une nouvelle classe de molécules naturelles formées in vivo par un mécanisme radicalaire non enzymatique de peroxydation lipidique des acides gras polyinsaturés. La quantification de ces composés comme marqueur de peroxydation lipidique in vivo apparaît comme une avancée importante dans l’exploration du rôle du stress oxydant en pathologie humaine. Un grand nombre de travaux a été réalisé dans le domaine de l’analyse des isoprostanes. Cependant, ces travaux diffèrent dans la préparation de l’échantillon comme pour le choix de la technique analytique et aucune méthode standard n'émerge. Les procédures d’extraction et de purification qui nécessitent une succession de techniques chromatographiques, sont longues, difficiles à mettre en œuvre et ne donnent que de faibles taux de récupération. Par ailleurs, deux méthodes sont couramment utilisées pour la quantification des isoprostanes : la spectrométrie de masse et les méthodes immunologiques. L’objectif de cette revue et de faire le point sur les différentes méthodes publiées à ce jour sur l’extraction, la purification et l’analyse des isoprostanes dans les différents échantillons biologiques

Norepinephrine and ephedrine do not counteract the increase in cutaneous microcirculation induced by spinal anaesthesia.

BACKGROUND: /st> Neuraxial anaesthesia improves tissue perfusion and tissue oxygen tension. Vasodilation induced by this technique may result in hypotension requiring the administration of vasoactive drugs. The use of peripheral vasoconstrictors might counteract the improved tissue perfusion and its potentially beneficial effects. We therefore investigated the effect of i.v. norepinephrine and ephedrine on skin perfusion using laser-Doppler flowmetry (LDF) in patients during spinal anaesthesia. METHODS: /st> Skin blood flow expressed in perfusion units (PU) provided by LDF was measured simultaneously at the foot and the manubrium levels in 44 patients during spinal anaesthesia with a sensory level below T5. Norepinephrine infusion was then titrated to normalize mean arterial pressure (MAP) in 23 patients (Group NOR). Ephedrine (max. 10 mg) was administered in 21 patients (Group EPH). Changes in relative PU were compared between the two sites of measurements in each group during drug administration. The same doses of norepinephrine were assessed in 11 normal volunteers to assure comparable vasoreactivity at the foot and manubrium levels. RESULTS: /st> Spinal anaesthesia resulted in a 10% decrease in MAP (P Improved skin perfusion induced by spinal anaesthesia was not counteracted by the use of norepinephrine or ephedrine

Evidence for caveolin-1 as a new susceptibility gene regulating tissue fibrosis in systemic sclerosis

Objective Caveolin-1 (CAV1) is an inhibitor of tissue fibrosis and has been implicated in the pathogenesis of systemic sclerosis (SSc). The aim of the study was to analyse the possible association of CAV1 gene single nucleotide polymorphisms (SNP) with SSc. Methods A total population of 3974 individuals (1355 SSc patients, 2619 controls) was studied. Genotype data for 23 SNP spanning the CAV1-CAV2 gene locus were obtained from a genome-wide scan conducted in a French population (564 SSc patients, 1776 controls). Three CAV1 SNP (rs926198, rs959173, rs9920) displaying the most significant associations with SSc and/or clinical phenotypes were then genotyped in an Italian population (791 SSc patients, 843 controls). CAV1 protein expression in skin biopsies was investigated by immunohistochemistry and western blotting. Results In the French population, the CAV1 rs959173 C minor allele showed a significant protective association with susceptibility to SSc (OR 0.71, 95% CI 0.59 to 0.86, p(adjusted)=0.009), and with the subset of patients with limited cutaneous SSc (OR 0.71, 95% CI 0.56 to 0.89, p(adjusted)=0.018). The association was replicated in the Italian population and strengthened in the combined populations through Cochran-Mantel-Haenszel meta-analysis (SSc: pooled OR 0.81, 95% CI 0.71 to 0.92, p=0.0018; limited cutaneous SSc: pooled OR 0.80, 95% CI 0.69 to 0.93, p=0.0053). Genotype/protein expression correlations revealed that the rs959173 C protective allele was associated with increased CAV1 protein expression. Conclusions These results add CAV1 to the list of SSc susceptibility genes and provide further evidence for the contribution of this pathway in the fibrotic process that characterises SSc pathogenesis

Association of the CD226 Ser(307) Variant With Systemic Sclerosis Evidence of a Contribution of Costimulation Pathways in Systemic Sclerosis Pathogenesis

Objective. The nonsynonymous polymorphism rs763361 of the CD226 gene, which encodes DNAX accessory molecule 1, which is involved in T cell co-stimulation pathways, has recently been identified as a genetic risk factor for autoimmunity. The purpose of this study was to test for association of the CD226 rs763361 polymorphism with systemic sclerosis (SSc) in European Caucasian populations. Methods. CD226 rs763361 was genotyped in 3,632 individuals, consisting of a discovery sample (991 SSc patients and 1,008 controls) and a replication sample (999 SSc patients and 634 controls). All study subjects were of European Caucasian origin. Expression of CD226 was assessed on peripheral blood mononuclear cells obtained from 21 healthy donors genotyped for CD226 rs763361. Results. The CD226 rs763361 T allele was found to be associated with SSc in both the discovery and the replication samples, showing the following results in the combined populations: odds ratio (OR) 1.22 (95% confidence interval [95% CI] 1.10-1.34), P = 5.69 x 10(-5). The CD226 T allele was also associated with various SSc subsets, highlighting a potential contribution to disease severity. The most remarkable associations of the CD226 TT risk genotype were observed with the diffuse cutaneous SSc subtype, the anti-topoisomerase I antibody-positive, and SSc-related fibrosing alveolitis subsets: OR 1.86 (95% CI 1.42-2.43), P = 5.15 x 10(-6), OR 1.82 (95% CI 1.38-2.40), P = 2.16 x 10(-5), and OR 1.61 (95% CI 1.25-2.08), P = 2.73 x 10(-4), respectively. CD226 expression was not significantly influenced by CD226 rs763361 genotypes whatever the T cell subtype investigated. Conclusion. Our results establish CD226 as a new SSc genetic susceptibility factor underlying the contribution of costimulation pathways in the pathogenesis of SSc. Further work is nevertheless needed to define the causal variant at the CD226 locus as well as the functional consequences