Fonction des rétinoïdes dans les membranes foetales humaines. Action pro-cicatrisante médiée par LOXL4.

Vitamin A and its active derivates (retinoids) are essential molecules for life from the embryonic development to the adulthood. Because of these numerous functions and especially because of their pro-healing properties, they are commonly used in clinic in dermatology and ophthalmology in particular. Despite this routine clinical use, the molecular and cellular mechanisms used by retinoids to promote a healing process remain unclear. To better understand these mechanisms, but also to expand its clinical use to the premature rupture of fetal membranes (PROM), we looked to pro-healing properties of atRA (active derivative of vitamin A) on the human fetal membranes. While amnion and chorion are unable to initiate a physiological process of healing after injury, our results demonstrate a positive effect of atRA on the migration of primary amniocytes, leading to an healing improvement of up to 80% in vitro. This work, completed by a transcriptomic analysis performed on fetal membranes and primary amniocytes treated or not with atRA, allowed the identification of many genes regulated by atRA within the amnion and the amniocytes. Among these genes, we looked to a member of the lysyl oxidase family, LOXL4, which plays a key role in the dynamic of the extracellular matrix by regulating collagen crosslinking. First, transcription and promotology experiments have shown that atRA strongly induced the expression of LOXL4 in a direct manner. Then, the inhibition of the LOXL4 protein in scratch assay experiments (using β-aminopropionitrile or a specific siRNA) allowed us to demonstrate that the pro-healing effect of atRA was mediated, at least in part, by the retinoid-induction of this gene. Besides providing new elements to understand how atRA exerts their pro-healing properties, this work proposes atRA as a promising candidate to improve the clinical management of premature rupture of the fetal membranes by promoting re-epithelialization of the amnion.La vitamine A et ses dérivés actifs (les rétinoïdes) sont des molécules essentielles à la vie et ce dès la période embryonnaire. Molécules de choix dans de nombreuses applications thérapeutiques, notamment dans les domaines de la dermatologie et de l’ophtalmologie, elles sont le plus couramment utilisées pour leurs propriétés pro-cicatrisantes. Malgré cette utilisation courante en clinique, les mécanismes cellulaires et moléculaires permettant aux rétinoïdes de promouvoir un processus de cicatrisation restent encore mal connus. Afin de mieux appréhender ces mécanismes, mais aussi afin d’élargir leur utilisation clinique à la rupture prématurée des membranes (RPM), je me suis intéressée aux propriétés pro-cicatrisantes de l’atRA (l’un des dérivés actifs de la vitamine A) sur les membranes fœtales. Alors que l’amnios et le chorion sont physiologiquement incapables d’initier un processus de cicatrisation suite à une lésion, nos résultats démontrent un effet positif de l’atRA sur la migration des cellules épithéliales amniotiques (amniocytes primaires), conduisant ainsi à une potentialisation de la cicatrisation de plus de 80% in vitro. Ce travail, complété par une analyse transcriptomique réalisée sur des membranes fœtales et des amniocytes primaires traités ou non à l’atRA, a permis d’identifier de nombreux gènes régulés par l’atRA au sein de l’amnios et des amniocytes. Parmi ces gènes, je me suis intéressée à un membre de la famille des lysyl oxydases, LOXL4, qui joue un rôle clé dans la dynamique de la matrice extracellulaire en régulant la réticulation du collagène. Une étude de régulation transcriptionnelle associée à de la promotologie ont tout d’abord permis de montrer que l’atRA induisait l’expression du gène LOXL4 de manière directe. Puis, l’inhibition de la protéine LOXL4 lors de tests de blessure (par le β-aminopropionitrile et par un siARN spécifique) nous a permis de démontrer que l’effet pro-cicatrisant de l’atRA était médié, au moins en partie, par la rétino-induction deLOXL4. Ces nouveaux éléments apportés par ce travail dans la compréhension des mécanismes moléculaires utilisés par l’atRA afin de promouvoir la cicatrisation permettent d’envisager son utilisation future dans la prise en charge clinique des ruptures prématurées

Function of retinoids in human fetal membranes. Wound-healing action mediated by LOXL4.

La vitamine A et ses dérivés actifs (les rétinoïdes) sont des molécules essentielles à la vie et ce dès la période embryonnaire. Molécules de choix dans de nombreuses applications thérapeutiques, notamment dans les domaines de la dermatologie et de l’ophtalmologie, elles sont le plus couramment utilisées pour leurs propriétés pro-cicatrisantes. Malgré cette utilisation courante en clinique, les mécanismes cellulaires et moléculaires permettant aux rétinoïdes de promouvoir un processus de cicatrisation restent encore mal connus. Afin de mieux appréhender ces mécanismes, mais aussi afin d’élargir leur utilisation clinique à la rupture prématurée des membranes (RPM), je me suis intéressée aux propriétés pro-cicatrisantes de l’atRA (l’un des dérivés actifs de la vitamine A) sur les membranes fœtales. Alors que l’amnios et le chorion sont physiologiquement incapables d’initier un processus de cicatrisation suite à une lésion, nos résultats démontrent un effet positif de l’atRA sur la migration des cellules épithéliales amniotiques (amniocytes primaires), conduisant ainsi à une potentialisation de la cicatrisation de plus de 80% in vitro. Ce travail, complété par une analyse transcriptomique réalisée sur des membranes fœtales et des amniocytes primaires traités ou non à l’atRA, a permis d’identifier de nombreux gènes régulés par l’atRA au sein de l’amnios et des amniocytes. Parmi ces gènes, je me suis intéressée à un membre de la famille des lysyl oxydases, LOXL4, qui joue un rôle clé dans la dynamique de la matrice extracellulaire en régulant la réticulation du collagène. Une étude de régulation transcriptionnelle associée à de la promotologie ont tout d’abord permis de montrer que l’atRA induisait l’expression du gène LOXL4 de manière directe. Puis, l’inhibition de la protéine LOXL4 lors de tests de blessure (par le β-aminopropionitrile et par un siARN spécifique) nous a permis de démontrer que l’effet pro-cicatrisant de l’atRA était médié, au moins en partie, par la rétino-induction deLOXL4. Ces nouveaux éléments apportés par ce travail dans la compréhension des mécanismes moléculaires utilisés par l’atRA afin de promouvoir la cicatrisation permettent d’envisager son utilisation future dans la prise en charge clinique des ruptures prématurées.Vitamin A and its active derivates (retinoids) are essential molecules for life from the embryonic development to the adulthood. Because of these numerous functions and especially because of their pro-healing properties, they are commonly used in clinic in dermatology and ophthalmology in particular. Despite this routine clinical use, the molecular and cellular mechanisms used by retinoids to promote a healing process remain unclear. To better understand these mechanisms, but also to expand its clinical use to the premature rupture of fetal membranes (PROM), we looked to pro-healing properties of atRA (active derivative of vitamin A) on the human fetal membranes. While amnion and chorion are unable to initiate a physiological process of healing after injury, our results demonstrate a positive effect of atRA on the migration of primary amniocytes, leading to an healing improvement of up to 80% in vitro. This work, completed by a transcriptomic analysis performed on fetal membranes and primary amniocytes treated or not with atRA, allowed the identification of many genes regulated by atRA within the amnion and the amniocytes. Among these genes, we looked to a member of the lysyl oxidase family, LOXL4, which plays a key role in the dynamic of the extracellular matrix by regulating collagen crosslinking. First, transcription and promotology experiments have shown that atRA strongly induced the expression of LOXL4 in a direct manner. Then, the inhibition of the LOXL4 protein in scratch assay experiments (using β-aminopropionitrile or a specific siRNA) allowed us to demonstrate that the pro-healing effect of atRA was mediated, at least in part, by the retinoid-induction of this gene. Besides providing new elements to understand how atRA exerts their pro-healing properties, this work proposes atRA as a promising candidate to improve the clinical management of premature rupture of the fetal membranes by promoting re-epithelialization of the amnion

Predictors of Short Latency Period Exceeding 48 h after Preterm Premature Rupture of Membranes

International audienceBackground: Preterm premature rupture of membranes (PPROM) is a complication responsible for a third of preterm births. Clinical management is initially hospital based, but homecare management is possible if patients are clinically stable 48 h after PPROM. This study set out to determine factors that are predictive of short latency (delivery ≤ 7 days) exceeding 48 h after PPROM, enabling estimation of the prevalence of maternal and neonatal complications and comparison of maternal and fetal outcomes between inpatient and outpatient management. Method: This was a monocentric retrospective study conducted between 1 January 2010 and 28 February 2017 on all patients experiencing PPROM at 24 to 34 weeks + 6 days and who gave birth after 48 h. Maternal, obstetric, fetal, and neonatal variables were included in the data collected. The primary endpoint was latency, defined as the number of days between rupture of membranes and delivery. Results: 170 consecutive patients were analyzed. Short latency could be predicted by the need for tocolysis, a cervical length less than 25 mm at admission and the existence of anamnios. Outpatient follow-up was not found to lead to increased maternal morbidity or neonatal mortality. Conclusion: Our study highlights predictive factors of short latency exceeding 48 h after PPROM. Knowledge of these factors may provide justification for outpatient monitoring of patients presenting with a long cervix, absence of need for tocolysis and persistence of amniotic fluid and, thus, no risk factors after 48 h of admission

Retinoic Acid Pathway Regulation of Vascular Endothelial Growth Factor in Ovine Amnion

International audienceVascular endothelial growth factor (VEGF) has been proposed as an important regulator of amniotic fluid absorption across the amnion into the fetal vasculature on the surface of the placenta. However, the activators of VEGF expression and action in the amnion have not been identified. Using the pregnant sheep model, we aimed to investigate the presence of the retinoic acid (RA) pathway in ovine amnion and to determine its effect on VEGF expression. Further, we explored relationships between RA receptors and VEGF and tested the hypothesis that RA modulates intramembranous absorption (IMA) through induction of amnion VEGF in sheep fetuses subjected to altered IMA rates. Our study showed that RA receptor isoforms were expressed in sheep amnion, and RA response elements (RAREs) were identified in ovine RARβ and VEGF gene promoters. In ovine amnion cells, RA treatment upregulated RARβ messenger RNA (mRNA) and increased VEGF transcript levels. In sheep fetuses, increases in IMA rate was associated with elevated VEGF mRNA levels in the amnion but not in the chorion. Further, RARβ mRNA was positively correlated with VEGF mRNA levels in the amnion and not chorion. We conclude that an RA pathway is present in ovine fetal membranes and that RA is capable of inducing VEGF. The finding of a positive relationship between amnion VEGF and RARβ during altered IMA rate suggests that the retinoid pathway may play a role through VEGF in regulating intramembranous transport across the amnion

Method validation of a set of 12 GEM® Premier™ 4000 blood gas analyzers for point-of-care testing in a university teaching hospital

International audienceBackground: Blood gas analyzers are o0.ften integrated into point-of-care testing provisions. International standards (ISO 22870 and 15189) as adapted to French COFRAC regulations make accreditation of point-ofta-care testintag obligatory. We installed and assessed 12 GEM PREMIER 4000 analyzers for pH, pCO 2 , pO 2 , Na + , K + , Cl-, Ca 2+ , lactate, hemoglobin and oxyhemoglobin (O 2 Hb) at Clermont-Ferrand Hospital. These instruments were distributed across 11 care sites in the hospital. Methods: Precision was studied at two control levels for each parameter. Comparisons between GEM analyzers were performed (on 30 samples) for pH, pCO 2 , pO 2 , Na + , K + , Cl-, Ca 2+ , lactate, hemoglobin and O 2 Hb; and between GEM analyzers and the central laboratory for Na + , K + , Cl-, Ca 2+ and hemoglobin (on 30-50 samples). Uncertainty in measurement (UM) was evaluated with an approach using reproducibility and accuracy data. Results: The coefficients of variation (CVs) were in line with recommendations, except for the repeatability CV for pO 2. All CVs were below 4%. All comparisons complied with recommendations. Uncertainties of measurement were also validated. Conclusion: Our results met standard requirements and the 12 analyzers were assessed as suitable for point-of-care testing in services of academic medical centers, as exemplified at Clermont-Ferrand hospital

Factors of Non-Compliance with a Protocol for Oral Administration of Misoprostol (Angusta^®) 25 Micrograms to Induce Labor: An Observational Study

We set out to identify factors of non-compliance with a protocol for the oral administration of misoprostol 25 µg (Angusta®) every 2 h (up to eight tablets), for the induction of labor (IOL). We conducted a retrospective study on IOL at term, on singleton pregnancies from 2019 to 2021, in a university hospital. The study included 195 patients, comprising 144 compliant protocols. Pain was statistically more frequent in the non-compliance group (92.2% vs. 62.5%, p p < 0.001). A multivariable analysis found factors of good response (defined as going into labor before the administration of the median number of tablets, i.e., six) to be an indication for PROM (OR: 12.03, 95% CI: 5.42–26.71), and gestational age at induction (OR: 1.54, 95% CI: 1.19–2.01), independently of BMI, initial Bishop score, and parity. Patients with pain who were able to follow the protocol delivered 9 h earlier than patients with pain who interrupted the protocol and 16 h earlier than patients who experienced no pain. We identified two key elements that favored compliance: (i) providing the next tablet in advance; and (ii) offering patients early epidural analgesia when in pain in order to continue the protocol and go into labor promptly

Le condensé de cigarettes perturbe le signal rétinoïdes au sein de l'amnios humain

International audienceIntroduction: The preterm premature rupture of membranes (PPROM) is a frequent pathology responsible of more than 30% of preterm births. Tobacco smoking is one of the most frequently described risk factors identified and contributes to the pre term weakening of fetal membranes. As previously demonstrated, all-trans retinoic acid (atRA) regulates several genes involved in the extracellular matrix dynamics, an essential actor in fetal membrane ruptures. We hypothesized that cigarette smoke may affect this pathway in human amnion. Methods: Amnion was obtained from full-term fetal membranes collected from non-smoking women after cesarean births and used either as explants or for the isolation of derived epithelial cells. The pro-healing and transcriptomic effects of atRA were studied by a scratch assay experiment and quantitative RT-PCR, respectively, after treatment with dimethyl sulfoxyde (DMSO), atRA, DMSO þ cigarette smoke condensate (CSC), or atRA þ CSC. Results: Our results show a strong alteration of the retinoid pathway after CSC treatment on amnion-derived epithelial cells and explants. We first demonstrated that CSC inhibits the activity of the RARE reporter gene in amnion-derived epithelial cells. Then, atRA's effects on both the transcription of its target genes and wound healing were demonstrated to be inhibited or at least decreased by the CSC in human amnion epithelial cells. Discussion: Here, we demonstrated that CSC altered the retinoid signal, already known to have roles in fetal membrane physiopathology. These results highlight a potential negative action of maternal smoking on the retinoid pathway in human amnion and more generally on pregnancy

Nuclear retinoid receptors and pregnancy: placental transfer, functions, and pharmacological aspects

International audienceAnimal models of vitamin A (retinol) deficiency have highlighted its crucial role in reproduction and placentation, whereas an excess of retinoids (structurally or functionally related entities) can cause toxic and teratogenic effects in the embryo and foetus, especially in the first trimester of human pregnancy. Knock-out experimental strategies-targeting retinoid nuclear receptors RARs and RXRs have confirmed that the effects of vitamin A are mediated by retinoic acid (especially all-trans retinoic acid) and that this vitamin is essential for the developmental process. All these data show that the vitamin A pathway and metabolism are as important for the well-being of the foetus, as they are for that of the adult. Accordingly, during this last decade, extensive research on retinoid metabolism has yielded detailed knowledge on all the actors in this pathway, spurring the development of antagonists and agonists for therapeutic and research applications. Natural and synthetic retinoids are currently used in clinical practice, most often on the skin for the treatment of acne, and as anti-oncogenic agents in acute promyelocytic leukaemia. However, because of the toxicity and teratogenicity of retinoids during pregnancy, their pharmacological use needs a sound knowledge of their metabolism, molecular aspects, placental transfer, and action

Évolution du Shock Index obstétrical lors d’une hémorragie du post-partum selon le recours à la sulprostone

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Risk Factors for Perineal Wound Breakdown in Early Postpartum: A Retrospective Case–Control Study

We conducted a retrospective case–control study in patients presenting a perineal tear (second degree or higher) or episiotomy complicated by wound breakdown during maternity stay to identify risk factors associated with wound breakdown in early postpartum with a view to improving the quality of care. We collected ante- and intrapartum characteristics and outcomes at the postpartum visit. In all, 84 cases and 249 control subjects were included. In univariate analysis, primiparity, absence of history of vaginal delivery, a longer second phase of labour, instrumental delivery, and a higher degree of laceration emerged as risk factors for early perineal suture breakdown postpartum. Gestational diabetes, peripartum fever, streptococcus B, and suture technique did not emerge as risk factors for perineal breakdown. Multivariate analysis confirmed that instrumental delivery (OR = 2.18 [1.07; 4.41], p = 0.03) and a longer second phase of labour (OR = 1.72 [1.23; 2.42], p = 0.001) were risk factors for early perineal suture breakdown.</jats:p