Implication de HMGB1 dans la différentiation des trophoblastes

Le placenta est l'organe essentiel au succès de la grossesse et la différenciation des trophoblastes est fondamentale pour son bon fonctionnement. La présence d’une inflammation non contrôlée, habituellement induite par des médiateurs inflammatoires endogènes, est associée à plusieurs complications de la grossesse. High Mobility Group Box 1 (HMGB1), une protéine nucléaire qui peut avoir des actions inflammatoires lorsque secrétée dans le milieu extracellulaire, est un des médiateurs inflammatoires endogènes augmentés lors des grossesses pathologiques. Cependant, la manière dont HMGB1 agit à l’interface materno-foetale est encore inconnue. Ce travail de maîtrise a comme objectifs d’évaluer la concentration, la localisation subcellulaire et la sécrétion de HMGB1 lors de la différentiation des trophoblastes et d’étudier sa distribution dans le placenta de grossesses compliquées par une préeclampsie (PE). Dans ces travaux, nous avons démontré une augmentation de la concentration nucléaire de HMGB1 lors de la différenciation spontanée des trophoblastes. De plus, l’utilisation d’un inhibiteur d’histones déacétylases (c.-à-d. NaB) mène à une accumulation de HMGB1 dans le cytoplasme et favorise la différenciation, tandis que l’utilisation d’un inhibiteur de l’export nucléaire (c.-à-d. leptomycine) mène à une diminution de la différenciation. En ce qui concerne les grossesses compliquées par la PE, il y a une redistribution de HMGB1 avec une accumulation cytoplasmique. En conclusion, ces travaux démontrent l’association entre la modulation de HMGB1 et la différentiation des trophoblastes, bien que le lien causal reste à déterminer.The placenta plays a crucial role during pregnancy and trophoblast differentiation is fundamental to its proper functioning. The absence of inflammation is also essential for the success of gestation, the presence of uncontrolled inflammation is associated with several pregnancy complications, such as preeclampsia (PE) and preterm delivery. High Mobility Group Box 1 (HMGB1), a nuclear protein that acts as a pro-inflammatory mediator when secreted into the extracellular media, is one of the endogenous inflammatory mediators increased during pathological pregnancies. However, the actions of HMGB1 at the materno-fetal interface are still unknown. The aim of this work was to evaluate the concentration, subcellular localization and secretion of HMGB1 during trophoblast differentiation and to evaluate the distribution of HMGB1 in the placenta from pregnancies complicated with PE. In my studies I have shown an increase of HMGB1’s nuclear concentration during the spontaneous differentiation of trophoblasts. Moreover, the use of a histone deacetylase inhibitor (i.e. NaB) leads to an accumulation of HMGB1 in the cytoplasm and promotes differentiation, while the use of a nuclear export inhibitor (i.e. leptomycin) leads to a decrease in differentiation. Concerning pregnancies complicated with PE, there is a redistribution of HMGB1 with cytoplasmic accumulation. In conclusion, this work demonstrates the association between the modulation of HMGB1 localisation with trophoblasts differentiation, although the causal link remains to be determined

Agitation, confusion, and aggression in critically ill traumatic brain injury-a pilot cohort study (ACACIA-PILOT)

Abstract Background Agitated behaviors are problematic in intensive care unit (ICU) patients recovering from traumatic brain injury (TBI) as they create substantial risks and challenges for healthcare providers. To date, there have been no studies evaluating their epidemiology and impact in the ICU. Prior to planning a multicenter study, assessment of recruitment, feasibility, and pilot study procedures is needed. In this pilot study, we aimed to evaluate the feasibility of conducting a large multicenter prospective cohort study. Methods This feasibility study recruited adult patients admitted to the ICU with TBI and an abnormal cerebral CT scan. In all patients, we documented Richmond Agitation Sedation Score (RASS) and agitated behaviors every 8-h nursing shift using a dedicated tool documenting 14 behaviors. Our feasibility objectives were to obtain consent from at least 2 patients per month; completion of screening logs for agitated behaviors by bedside nurses for more than 90% of 8-h shifts; completion of data collection in an average of 6 h or less; and obtain 6-month follow-up for surviving patients. The main clinical outcome was the incidence of agitation and individual agitated behaviors. Results In total, 47 eligible patients were approached for inclusion and 30 (64% consent rate) were recruited over a 10-month period (3 patients/month). In total, 794 out of 827 (96%) possible 8-h periods of agitated behavior logs were completed by bedside nurses, with a median of 24 observations (IQR 28.0) per patient. During the ICU stay, 17 of 30 patients developed agitation (56.7%; 95% CI 0.37–0.75) defined as RASS ≥ 2 during at least one observation period and for a median of 4 days (IQR 5.5). At 6 months post-TBI, among the 24 available patients, an unfavorable score (GOS-E < 5 including death) was reported in 12 patients (50%). In the 14 patients who were alive and available at 6 months, the median QOLIBRI score was 74.5 (IQR 18.5). Conclusions This study demonstrates the feasibility of conducting a larger cohort study to evaluate the epidemiology and impact of agitated behaviors in critically ill TBI patients. This study also shows that agitated behaviors are frequent and are associated with adverse events