Etat de stress post-traumatique chez les mères et les pères d'enfants prématurés : similitudes et différences

Rapport de synthèse : Cette étude réalisée conjointement par les services de pédopsychiatrie et de néonatologie du Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Suisse, s'inscrit dans un groupe de publications issues d'un projet portant sur les représentations parentales et le devenir de 1a prématurité, financée par le Fonds National de la Recherche Scientifique entre 1998 et 2002 (FNRS 32-49712.96), soutenue par la Fondation de la Psychiatrie pour la Petite Enfance. Elle à pour objectifs d'évaluer et de compazer la présence de symptômes de stress post-traumatique; en fonction de la gravité de la prématurité, chez les mères et chez les pères de bébés nés prématurément. Population et Méthode : en fonction du score de risque périnatal (PERI) du bébé, les parents des prématurés (âge gestationnel < 34 semaines) ont été divisés en deux groupes : les parents de prématurés à faible risque (n = 16) et à haut risque (n = 26). Les symptômes d'intrusion et d'évitement, de l'état de stress post-traumatique, ont été évalués chez les parents à l'aide d'un questionnaire rempli par les parents, l'Impact of Event Scale (IES). Leurs réponses ont été comparées à un groupe contrôle de parents de nouveau-nés à terme (n = 24). Les différences entre les réponses des mères et des pères, ont été analysées. Résultats : les parents de bébés prématurés sont plus à risque que les parents de nouveau-nés à terme, de présenter des symptômes de stress post-traumatique. Les mères en lien avec le fait même de la prématurité du bébé, les pères en lien avec la gravité de la prématurité. Les mèrés et les pères des prématurés des deux groupes (prématurés à faible risque, prématurés à haut risque) décrivent des symptômes d'intrusion, alors que les symptômes d'évitement sont décrits par toutes les mères, mais seulement par les pères de prématurés à haut risque périnatal. Le vécu particulier des parents, ainsi que les enjeux différents pour les mères et les pères lors d'une naissance prématurée, sont ainsi mis en évidence. La prise en compte de ces différences devrait influencer les interventions des pédopsychiatres et des équipes de néonatologie qui interviennent auprès des parents et guident la construction des liens avec le bébé né prématurément. Publiée par la revue «Neuropsychiatrie de l'enfance et de l'adolescence », aux éditions Elsevier Masson sous le titre : « Etat de stress post-traumatique chez les mères et chez les pères d'enfants prématurés : similitudes et différences» ; numéró 57 (2009) 385-391.

Expanding view of phenotype and oxidative stress in Friedreich's ataxia patients with and without idebone.

Friedreich's ataxia (FRDA), the most common autosomal recessive ataxia, is characterised by progressive ataxia with dysarthria of speech, loss of deep-tendon reflexes, impaired vibratory and proprioceptive sensations and corticospinal weakness with a Babinski's sign. Patients eventually also develop kyphoscoliosis, cardiomyopathy and diabetes mellitus. The disease is a GAA repeat disorder resulting in severely reduced levels of frataxin, with secondary increased sensitivity to oxidative stress. The anti-oxidative drug, idebenone, is effective against FRDA-associated cardiomyopathy. We provide detailed clinical, electrophysiological and biochemical data from 20 genetically confirmed FRDA patients and have analysed the relationship between phenotype, genotype and malondialdehyde (MDA), which is a marker of superoxide formation. We assessed the effects of idebenone biochemically by measuring blood MDA and clinically by serial measurements of the International Cooperative Ataxia Rating Scale (ICARS). The GAA repeat length influenced the age at onset (p <0.001), the severity of ataxia (p = 0.02), the presence of cardiomyopathy (p = 0.04) and of low-frequency hearing loss (p = 0.009). Multilinear regression analysis showed (p = 0.006) that ICARS was dependent on the two variables of disease duration (p = 0.01) and size of the GAA expansion (p = 0.02). We found no correlation to bilateral palpebral ptosis, visual impairment, diabetes mellitus or skeletal deformities, all of which appear to be signs of disease progression rather than severity. We discuss more thoroughly two underrecognised clinical findings: palpebral ptosis and GAA length-dependent low-frequency hearing loss. The average ICARS remained unchanged in 10 patients for whom follow-up on treatment was available (mean 2.9 years), whereas most patients treated with idebenone reported an improvement in dysarthria (63%), hand dexterity (58%) and fatigue (47%) after taking the drug for several weeks or months. Oxidative stress analysis showed an unexpected increase in blood MDA levels in patients on idebenone (p = 0.04), and we discuss the putative underlying mechanism for this result, which could then explain the unique efficacy of idebenone in treating the FRDA-associated cardiomyopathy, as opposed to other antioxidative drugs. Indeed, idebenone is not only a powerful stimulator of complexes II and III of the respiratory chain, but also an inhibitor of complex I activity, then promoting superoxide formation. Our preliminary clinical observations are the first to date supporting an effect of idebenone in delaying neurological worsening. Our MDA results point to the dual effect of idebenone on oxidative stress and to the need for controlled studies to assess its potential toxicity at high doses on the one hand, and to revisit the exact mechanisms underlying the physiopathology of Friedreich's ataxia on the other hand, while recent reports suggest non-oxidative pathophysiology of the disease.

Patients presenting with somatic complaints in general practice : dépression, anxiety and somatoform disorders are frequent and associated with psychosocial stressors

RAPPORT DE SYNTHÈSE Introduction En médecine de premier recours, les plaintes physiques sont fréquemment associées à des troubles dépressifs, anxieux et somatoformes et peuvent les masquer. Il est fréquemment reporté que ces troubles mentaux ont tendance à être insuffisamment diagnostiqués. Par ailleurs, peu d'études ont été conduites en médecine de premier recours concernant la possible association entre facteurs de stress psychosociaux et troubles dépressifs, anxieux et somatoformes. Objectifs Les objectifs étaient de déterminer la prévalence des troubles dépressifs, anxieux et somatoformes chez des patients consultant avec une plainte physique en médecine de premier recours, ainsi que d'explorer la possible association entre ces troubles mentaux et des facteurs de stress psychosociaux. Méthodes Nous avons conduit une étude transversale, multicentrique parmi vingt et un cabinets médicaux en Suisse Romande et la Policlinique Médicale Universitaire de Lausanne. Les sujets étaient sélectionnés aléatoirement parmi des patients qui avaient présenté spontanément au moins une plainte physique et qui avaient consulté lors d'une demi- journée de consultation considérée pour l'étude. Les patients inclus ont rempli l'auto- questionnaire Patient Health Questionnaire (PHQ) entre novembre 2004 et juillet 2005. Nous avons utilisé la version française et validée du PHQ qui permet le diagnostic des principaux troubles mentaux selon les critères du DSM-IV et l'analyse de l'exposition aux facteurs de stress psychosociaux. Résultats Neuf cent dix-sept patients se présentant avec au moins une plainte physique ont été inclus. Le taux de troubles dépressifs, anxieux et somatoformes a été de 20,0% (intervalle de confiance [IC] à 95% = 17,4%-22,7%), 15,5% (IC 95% = 13,2%- 18,0%) et 15,1% (IC 95% = 12,8%~17,5%), respectivement. Les facteurs de stress psychosociaux ont été significativement associés aux troubles mentaux. Les patients avec une accumulation de facteurs de stress psychosociaux ont été le plus souvent déprimés, anxieux ou ont manifesté des troubles somatoformes, avec une augmentation par un facteur 2,2 (IC 95% = 2,0-2,5) pour chaque facteur additionnel. Conclusions Bien que la relation entre facteurs de stress psychosociaux et trouble dépressif soit bien établie, cette étude montre qu'il existe un lien entre ces facteurs de stress et les troubles dépressifs, anxieux et somatoformes. L'investigation de ces troubles mentaux chez des patients consultant avec un symptôme physique en médecine de premier recours est pertinente. D'autres explorations sont nécessaires pour investiguer le bénéfice potentiel d'une prise en charge intégrée des facteurs de stress psychosociaux sur la diminution des plaintes physiques et des troubles mentaux chez les patients que suivent les médecins de premier recours.

The level of ascorbate peroxidase is enhanced in benznidazole-resistant populations of Trypanosoma cruzi and its expression is modulated by stress generated by hydrogen peroxide

Ascorbate peroxidases (APX) are class I heme-containing enzymes that convert hydrogen peroxide into water molecules. The gene encoding APX has been characterized in 11 strains of Trypanosoma cruzi that are sensitive or resistant to benznidazole (BZ). Bioinformatic analysis revealed the presence of two complete copies of the T. cruzi APX (TcAPX) gene in the genome of the parasite, while karyotype analysis showed that the gene was present in the 2.000-kb chromosome of all of the strains analyzed. The sequence of TcAPX exhibited greater levels of similarity to those of orthologous enzymes from Leishmania spp than to APXs from the higher plant Arabidopsis thaliana. Northern blot and real-time reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed no significant differences in TcAPX mRNA levels between the T. cruzi strains analyzed. On the other hand, Western blots showed that the expression levels of TcAPX protein were, respectively, two and three-fold higher in T. cruzi populations with in vitro induced (17 LER) and in vivo selected (BZR) resistance to BZ, in comparison with their corresponding susceptible counterparts. Moreover, the two BZ-resistant populations exhibited higher tolerances to exogenous hydrogen peroxide than their susceptible counterparts and showed TcAPX levels that increased in a dose-dependent manner following exposure to 100 and 200 µM hydrogen peroxide.

Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide

To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods) and glutaredoxins (Grxs). The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

Extracellular matrix molecules enhance the neurotrophic effect of schwann cell-like differentiated adipose-derived stem cells and increase cell survival under stress conditions.

Since the first reports of induction of adipose-derived stem cells (ASC) into neuronal and glial cell phenotypes, expectations have increased regarding their use in tissue engineering applications for nerve repair. Cell adhesion to extracellular matrix (ECM) is a basic feature of survival, differentiation, and migration of Schwann cells (SC) during nerve regeneration, and fibronectin and laminin are two key molecules of this process. Interaction between ECM and SC-like differentiated ASC (dASC) could potentially improve the neurotrophic potential of the stem cells. We have investigated the effect of ECM molecules on SC-like dASC in terms of proliferation, adhesion, and cell viability. Fibronectin and laminin did not affect the proliferation of dASC when compared with cell adherent tissue culture plastic, but significantly improved viability and cell attachment when dASC were exposed to apoptotic conditions. To assess the influence of the ECM molecules on dASC neurotrophic activity, dASC were seeded onto ECM-coated culture inserts suspended above dorsal root ganglia (DRG) sensory neurons. Neurite outgrowth of DRG neurons was enhanced when dASC were seeded on fibronectin and laminin when compared with controls. When DRG neurons and dASC were in direct contact on the various surfaces there was significantly enhanced neurite outgrowth and coculture with laminin-conditioned dASC produced the longest neurites. Compared with primary SCs, dASC grown on laminin produced similar levels of neurite outgrowth in the culture insert experiments but neurite length was shorter in the direct contact groups. Anti β1 integrin blocking antibody could inhibit baseline and dASC evoked neurite elongation but had no effect on outgrowth mediated by laminin-conditioned dASC. ECM molecules had no effect on the levels of nerve growth factor and brain-derived neurotrophic factor secretion from dASC. The results of the study suggest that ECM molecules can significantly improve the potential of dASC for nerve regeneration.

Prevalence of symptomatic and silent stress-induced perfusion defects in diabetic patients with suspected coronary artery disease referred for myocardial perfusion scintigraphy.

PURPOSE: Silent myocardial ischaemia--as evaluated by stress-induced perfusion defects on myocardial perfusion scintigraphy (MPS) in patients without a history of chest pain--is frequent in diabetes and is associated with increased rates of cardiovascular events. Its prevalence has been determined in asymptomatic diabetic patients, but remains largely unknown in diabetic patients with suspected coronary artery disease (CAD) in the clinical setting. In this study we therefore sought (a) to determine the prevalence of symptomatic and silent perfusion defects in diabetic patients with suspected CAD and (b) to characterise the eventual predictors of abnormal perfusion. METHODS: The patient population comprised 133 consecutive diabetic patients with suspected CAD who had been referred for MPS. Studies were performed with exercise (41%) or pharmacological stress testing (1-day protocol, (99m)Tc-sestamibi, 201Tl or both). We used semi-quantitative analysis (20-segment polar maps) to derive the summed stress score (SSS) and the summed difference score (SDS). RESULTS: Abnormal MPS (SSS> or =4) was observed in 49 (37%) patients (SSS=4.9+/-8.4, SDS=2.4+/-4.7), reversible perfusion defects (SDS> or =2) in 40 (30%) patients [SSS=13.3+/-10.9; SDS=8.0+/-5.6; 20% moderate to severe (SDS>4), 7% multivessel] and fixed defects in 21 (16%) patients. Results were comparable between patients with and patients without a history of chest pain. Of 75 patients without a history of chest pain, 23 (31%, 95% CI=21-42%) presented reversible defects (SSS=13.9+/-11.3; SDS=7.4+/-1.2), indicative of silent ischaemia. Reversible defects were associated with inducible ST segment depression during MPS stress [odds ratio (OR)=3.2, p<0.01). Fixed defects were associated with erectile dysfunction in males (OR=3.7, p=0.02) and lower aspirin use (OR=0.25, p=0.02). CONCLUSION: Silent stress-induced perfusion defects occurred in 31% of the patients, a rate similar to that in patients with a history of chest pain. MPS could identify these patients with a potentially increased risk of cardiovascular events.

Effects of L-carnitine supplemented total parenteral nutrition on lipid and energy metabolism in postoperative stress.

During episodes of trauma carnitine-free total parenteral nutrition (TPN) may result in a reduction of the total body carnitine pool, leading to a diminished rate of fat oxidation. Sixteen patients undergoing esophagectomy were divided randomly in two equal isonitrogenous groups (0.2 g/kg.day). Both received TPN (35 kcal/kg.day; equally provided as long-chain triglycerides and glucose) over 11 days without (group A) and with (group B) L-carnitine supplementation (12 mg/kg.day = 75 mumol/kg.day). Compared with healthy controls, the total body carnitine pool prior to the operation was significantly reduced in both groups, suggesting a state of semistarvation and muscle wasting. In group A the plasma levels of total carnitine and its subfractions (free carnitine, short- and long-chain acylcarnitine) remained stable during the study whereas in group B the total plasma carnitine concentration rose mainly due to an increase in free carnitine. In group A the cumulative urinary carnitine losses were 11.5 +/- 2.6 mmol (= 15.5 +/- 3.1% of the estimated total body carnitine pool). In group B 3.1 +/- 1.9 mmol (= 11.1 +/- 7.6%) of the infused carnitine was retained in the immediate postoperative phase until day 6, but this amount was completely lost at completion of the study period. No significant differences in the respiratory quotient or in the plasma levels of triglycerides, free fatty acids, and ketone bodies were observed, between or within the groups, before the operation and after 11 days of treatment. It is concluded that the usefulness of carnitine supplementation during postoperative TPN was not apparent in the present patient material.