37 research outputs found

    Intact cord resuscitation in newborns with congenital diaphragmatic hernia: insights from a lamb model

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    IntroductionCongenital diaphragmatic hernia (CDH) is a rare condition characterized by pulmonary hypoplasia, vascular dystrophy, and pulmonary hypertension at birth. Validation of the lamb model as an accurate representation of human CDH is essential to translating research findings into clinical practice and understanding disease mechanisms. This article emphasizes the importance of validating the lamb model to study CDH pathogenesis and develop innovative therapeutics.Material and methodsAt 78 days of gestation, the fetal lamb's left forelimb was exposed through a midline laparotomy and hysterotomy, and a supra diaphragmatic thoracotomy was performed to allow the digestive organs to ascend into the thoracic cavity. At 138 ± 3 days of gestation, lambs were delivered via a cesarean section; then, with umbilical cord intact during 1 hour, the lambs were mechanically ventilated with gentle ventilation in a pressure-controlled mode for 2 h.ResultsCDH lambs exhibited a lower left lung-to-body weight ratio of 5.3 (2.03), p < 0.05, and right lung-to-body weight ratio of 8.2 (3.1), p < 0.05. They reached lower Vt/kg (tidal volume per kg) during the course of the resuscitation period with 1.2 (0.7) ml/kg at 10 min and 3 (1.65) ml/kg at 60 min (p < 0.05). Compliance of the respiratory system was lower in CDH lambs with 0.5 (0.3) ml/cmH2O at 60 min (p < 0.05) and 0.9 (0.26) ml/cmH2O at 120 min (p < 0.05). Differences between pre- and postductal SpO2 were higher with 15.1% (21.4%) at 20 min and 6.7% (14.5%) at 80 min (p < 0.05). CDH lambs had lower differences between inspired and expired oxygen fractions with 4.55% (6.84%) at 20 min and 6.72% (8.57%) at 60 min (p < 0.05). CDH lamb had lower left ventricle [2.73 (0.5) g/kg, p < 0.05] and lower right ventricle [0.69 (0.8), p < 0.05] to left ventricle ratio.DiscussionCDH lambs had significantly lower tidal volume than control lambs due to lower compliance of the respiratory system and higher airway resistance. These respiratory changes are characteristic of CDH infants and are associated with higher mortality rates. CDH lambs also exhibited pulmonary hypertension, pulmonary hypoplasia, and left ventricle hypoplasia, consistent with observations in human newborns. To conclude, our lamb model successfully provides a reliable representation of CDH and can be used to study its pathophysiology and potential interventions

    Nouvelles approches thérapeutiques de la pathologie pulmonaire par les suppléments alimentaires en période périnatale

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    Bronchopulmonary dysplasia (BPD), a common complication of prematurity, reached in 30% of newborns with very low birth weight. Persistent pulmonary hypertension of the newborn (PPHN), with or without BPD, results in poor adaptation to extrauterine life and occurs in various pathological conditions such as prematurity, sepsis, inhaled meconium, or diaphragmatic hernia Congenital. The mortality and morbidities of these two diseases are high in the perinatal period. Severe PPHN or BPD are refractory to current treatment.Polyunsaturated fatty acids omega-3 (ω-3 PUFA) are nutrients with beneficial properties on the circulatory and pulmonary system, but also on fetal development, demonstrated by many experimental and clinical studies. Dehydroepiandrosterone (DHEA) is a steroid hormone whose secretion levels in humans decreases with age. Recent studies have demonstrated a cardio-protective effect of diet DHEA supplementation but also a pulmonary vasodilator and preventive effect of DBP injury in experimental models.The aims of our study were : 1) to study the effect of PUFA ω-3 supplementation in an experimental model of hyperoxia-induced DBP in pups; 2) to study effect on pulmonary circulation of infusion of ω-3 PUFAs (in vivo) in model of chronically instrumented fetal sheep, and to analyze the mechanisms of action of ω-3 PUFA (isolated vascular rings); and finally 3) to study the in vivo effect of DHEA in fetal pulmonary circulation in the same model of fetal sheep and to understand the mechanisms of action of DHEA._x000D_We have demonstrated that supplementation with diet PUFA ω-3 on pregnant rats at the end of gestation and after birth prevent BPD injuries induced by chronic exposure to hyperoxia in pups. These lesions were found in the control groups (water and ω-6 PUFA). ω-3 PUFA supplementation did not prevent vascular remodeling.Infusion of eicosapentaenoic acid (EPA) in sheep fetus showed a potent pulmonary vasodilator effect as compared to docosahexaenoic acid (DHA) or excipient (low dose of ethanol). Vasorelaxant effect of EPA on pre-contracted isolated rings was more important than DHA at equivalent dose, and was dose- and endothelium-dependent. This effect involves NO production.Bolus DHEA perfusion in the pulmonary vascular bed study on instrumented fetal sheep highlighted an acute vasodilator effect. This effect was dose-dependent with a more pronounced and sustained decrease in PVR at highest doses of DHEA. Finally, mechanisms of action study found an inhibition of the effect of DHEA by the LNA, indicating that DHEA-induced vasodilation is NO dependant.Taken together, our results suggest that supplementation with ω-3 PUFAs and DHEA within the perinatal period may prevent BPD and PPHN in high risk conditions including preterm birth, premature rupture of the membrane or intrauterine growth restriction.La dysplasie broncho-pulmonaire (DBP), complication frĂ©quente de la prĂ©maturitĂ©, atteint 30% des nouveau-nĂ©s de faible poids de naissance. L’hypertension artĂ©rielle pulmonaire persistante du nouveau-nĂ© (HTAPP), associĂ© ou non Ă  la DBP, rĂ©sulte d’une mauvaise adaptation Ă  la vie extra-utĂ©rine et survient dans diverses situations pathologiques (prĂ©maturitĂ©, sepsis, inhalation de mĂ©conium, hernie diaphragmatique congĂ©nitale
). Ces 2 pathologies sont grevĂ©es d’une morbiditĂ© et d’une mortalitĂ© importante en pĂ©riode pĂ©rinatale. En effet, certaines situations d’HTAPP ou de DBP sĂ©vĂšres restent rĂ©fractaires aux thĂ©rapeutiques actuelles.Les acides gras polyinsaturĂ©s omĂ©ga 3 (AGPI ω-3) sont des nutriments aux propriĂ©tĂ©s bĂ©nĂ©fiques sur le systĂšme circulatoire et pulmonaire, mais Ă©galement sur le dĂ©veloppement fƓtal, dĂ©montrĂ©s par de nombreuses Ă©tudes expĂ©rimentales et cliniques. La dĂ©hydroĂ©piandrostĂ©rone (DHEA) est une hormone stĂ©roĂŻdienne dont le taux de sĂ©crĂ©tion chez l’homme diminue avec l’ñge. Des Ă©tudes rĂ©centes ont dĂ©montrĂ© un effet cardio-protecteur mais Ă©galement un effet vasodilatateur pulmonaire et prĂ©ventif de lĂ©sions de DBP dans des modĂšles expĂ©rimentaux.Les buts de notre travail Ă©taient 1) d’étudier l’effet d’une supplĂ©mentation en AGPI ω-3 dans un modĂšle expĂ©rimental de DBP induite par hyperoxie chez le raton, 2) d’étudier l’effet circulatoire d’injection d’AGPI ω-3 (in vivo) dans un modĂšle d’étude de la circulation pulmonaire chez le fƓtus de brebis chroniquement instrumentĂ©, et d’étudier les mĂ©canismes d’action AGPI ω-3 (anneaux vasculaires isolĂ©s) , enfin 3) d’étudier l’effet circulatoire de la DHEA (in vivo) dans le modĂšle de fƓtus de brebis et d’étudier les mĂ©canismes d’actions de la DHEA sur la circulation pulmonaire fƓtale (in vivo)._x000D_Nous avons dĂ©montrĂ© que la supplĂ©mentation par voie orale en AGPI ω-3 de rates gestantes Ă  la fin de la gestation et aprĂšs la naissance permettait de prĂ©venir, chez les ratons nouveau-nĂ©s, les lĂ©sions de DBP induites par une exposition chronique Ă  l’hyperoxie. Ces lĂ©sions Ă©taient retrouvĂ©es dans les groupes contrĂŽles (eau et AGPI ω-6). Cette Ă©tude n’avait pas retrouvĂ©e d’effet bĂ©nĂ©fique des AGPI ω-3 sur le remodelage vasculaire induit.L’injection d’acide eicosapentaĂšnoique (EPA) chez le fƓtus de brebis a rĂ©vĂ©lĂ© un effet vasodilatateur pulmonaire puissant avec une baisse significative et prolongĂ©e des rĂ©sistances vasculaires pulmonaires (RVP), en comparaison Ă  l’injection d’acide docosahĂ©xaĂšnoique (DHA) ou de l’excipient (faible dose d’éthanol). L’effet vasorelaxant de l’EPA sur des anneaux isolĂ©s prĂ©-contractĂ©s Ă©tait plus important que celui du DHA Ă  dose Ă©quivalente, et il Ă©tait dose- et endothĂ©lium-dĂ©pendent. Enfin, cet effet impliquait la voie de production du NO puisqu’il Ă©tait diminuĂ© lors du traitement des anneaux par le L-Nitro-Arginine (LNA), inhibant la NO synthase.L’étude de perfusion en bolus de DHEA dans le lit pulmonaire vasculaire chez le fƓtus de brebis instrumentĂ© mettait en Ă©vidence un effet vasodilatateur bref. Cet effet Ă©tait dose-dĂ©pendant avec une baisse plus prononcĂ©e des RVP et une durĂ©e plus importante pour des doses de DHEA plus importantes. Enfin l’étude des mĂ©canismes d’action retrouvait une inhibition de l’effet de la DHEA par le LNA, dĂ©montrant une action vasodilatatrice par activation de production du NO.L’ensemble de ces travaux permet de suggĂ©rer que les AGPI ω-3 reprĂ©sentent des nutriments intĂ©ressants en pĂ©riode pĂ©rinatale (grossesse, allaitement et per os), notamment en traitement prĂ©ventif dans les situations Ă  risque de DBP, ou curatif en cas d’HTAPP. La DHEA reste une piste dans le traitement de l’HTAP, mais semble pour l’instant plus difficile Ă  instaurer en clinique humaine

    New therapeutic approaches to lung disease by dietary supplements in neonatal period

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    La dysplasie broncho-pulmonaire (DBP), complication frĂ©quente de la prĂ©maturitĂ©, atteint 30% des nouveau-nĂ©s de faible poids de naissance. L’hypertension artĂ©rielle pulmonaire persistante du nouveau-nĂ© (HTAPP), associĂ© ou non Ă  la DBP, rĂ©sulte d’une mauvaise adaptation Ă  la vie extra-utĂ©rine et survient dans diverses situations pathologiques (prĂ©maturitĂ©, sepsis, inhalation de mĂ©conium, hernie diaphragmatique congĂ©nitale
). Ces 2 pathologies sont grevĂ©es d’une morbiditĂ© et d’une mortalitĂ© importante en pĂ©riode pĂ©rinatale. En effet, certaines situations d’HTAPP ou de DBP sĂ©vĂšres restent rĂ©fractaires aux thĂ©rapeutiques actuelles.Les acides gras polyinsaturĂ©s omĂ©ga 3 (AGPI ω-3) sont des nutriments aux propriĂ©tĂ©s bĂ©nĂ©fiques sur le systĂšme circulatoire et pulmonaire, mais Ă©galement sur le dĂ©veloppement fƓtal, dĂ©montrĂ©s par de nombreuses Ă©tudes expĂ©rimentales et cliniques. La dĂ©hydroĂ©piandrostĂ©rone (DHEA) est une hormone stĂ©roĂŻdienne dont le taux de sĂ©crĂ©tion chez l’homme diminue avec l’ñge. Des Ă©tudes rĂ©centes ont dĂ©montrĂ© un effet cardio-protecteur mais Ă©galement un effet vasodilatateur pulmonaire et prĂ©ventif de lĂ©sions de DBP dans des modĂšles expĂ©rimentaux.Les buts de notre travail Ă©taient 1) d’étudier l’effet d’une supplĂ©mentation en AGPI ω-3 dans un modĂšle expĂ©rimental de DBP induite par hyperoxie chez le raton, 2) d’étudier l’effet circulatoire d’injection d’AGPI ω-3 (in vivo) dans un modĂšle d’étude de la circulation pulmonaire chez le fƓtus de brebis chroniquement instrumentĂ©, et d’étudier les mĂ©canismes d’action AGPI ω-3 (anneaux vasculaires isolĂ©s) , enfin 3) d’étudier l’effet circulatoire de la DHEA (in vivo) dans le modĂšle de fƓtus de brebis et d’étudier les mĂ©canismes d’actions de la DHEA sur la circulation pulmonaire fƓtale (in vivo)._x000D_Nous avons dĂ©montrĂ© que la supplĂ©mentation par voie orale en AGPI ω-3 de rates gestantes Ă  la fin de la gestation et aprĂšs la naissance permettait de prĂ©venir, chez les ratons nouveau-nĂ©s, les lĂ©sions de DBP induites par une exposition chronique Ă  l’hyperoxie. Ces lĂ©sions Ă©taient retrouvĂ©es dans les groupes contrĂŽles (eau et AGPI ω-6). Cette Ă©tude n’avait pas retrouvĂ©e d’effet bĂ©nĂ©fique des AGPI ω-3 sur le remodelage vasculaire induit.L’injection d’acide eicosapentaĂšnoique (EPA) chez le fƓtus de brebis a rĂ©vĂ©lĂ© un effet vasodilatateur pulmonaire puissant avec une baisse significative et prolongĂ©e des rĂ©sistances vasculaires pulmonaires (RVP), en comparaison Ă  l’injection d’acide docosahĂ©xaĂšnoique (DHA) ou de l’excipient (faible dose d’éthanol). L’effet vasorelaxant de l’EPA sur des anneaux isolĂ©s prĂ©-contractĂ©s Ă©tait plus important que celui du DHA Ă  dose Ă©quivalente, et il Ă©tait dose- et endothĂ©lium-dĂ©pendent. Enfin, cet effet impliquait la voie de production du NO puisqu’il Ă©tait diminuĂ© lors du traitement des anneaux par le L-Nitro-Arginine (LNA), inhibant la NO synthase.L’étude de perfusion en bolus de DHEA dans le lit pulmonaire vasculaire chez le fƓtus de brebis instrumentĂ© mettait en Ă©vidence un effet vasodilatateur bref. Cet effet Ă©tait dose-dĂ©pendant avec une baisse plus prononcĂ©e des RVP et une durĂ©e plus importante pour des doses de DHEA plus importantes. Enfin l’étude des mĂ©canismes d’action retrouvait une inhibition de l’effet de la DHEA par le LNA, dĂ©montrant une action vasodilatatrice par activation de production du NO.L’ensemble de ces travaux permet de suggĂ©rer que les AGPI ω-3 reprĂ©sentent des nutriments intĂ©ressants en pĂ©riode pĂ©rinatale (grossesse, allaitement et per os), notamment en traitement prĂ©ventif dans les situations Ă  risque de DBP, ou curatif en cas d’HTAPP. La DHEA reste une piste dans le traitement de l’HTAP, mais semble pour l’instant plus difficile Ă  instaurer en clinique humaine.Bronchopulmonary dysplasia (BPD), a common complication of prematurity, reached in 30% of newborns with very low birth weight. Persistent pulmonary hypertension of the newborn (PPHN), with or without BPD, results in poor adaptation to extrauterine life and occurs in various pathological conditions such as prematurity, sepsis, inhaled meconium, or diaphragmatic hernia Congenital. The mortality and morbidities of these two diseases are high in the perinatal period. Severe PPHN or BPD are refractory to current treatment.Polyunsaturated fatty acids omega-3 (ω-3 PUFA) are nutrients with beneficial properties on the circulatory and pulmonary system, but also on fetal development, demonstrated by many experimental and clinical studies. Dehydroepiandrosterone (DHEA) is a steroid hormone whose secretion levels in humans decreases with age. Recent studies have demonstrated a cardio-protective effect of diet DHEA supplementation but also a pulmonary vasodilator and preventive effect of DBP injury in experimental models.The aims of our study were : 1) to study the effect of PUFA ω-3 supplementation in an experimental model of hyperoxia-induced DBP in pups; 2) to study effect on pulmonary circulation of infusion of ω-3 PUFAs (in vivo) in model of chronically instrumented fetal sheep, and to analyze the mechanisms of action of ω-3 PUFA (isolated vascular rings); and finally 3) to study the in vivo effect of DHEA in fetal pulmonary circulation in the same model of fetal sheep and to understand the mechanisms of action of DHEA._x000D_We have demonstrated that supplementation with diet PUFA ω-3 on pregnant rats at the end of gestation and after birth prevent BPD injuries induced by chronic exposure to hyperoxia in pups. These lesions were found in the control groups (water and ω-6 PUFA). ω-3 PUFA supplementation did not prevent vascular remodeling.Infusion of eicosapentaenoic acid (EPA) in sheep fetus showed a potent pulmonary vasodilator effect as compared to docosahexaenoic acid (DHA) or excipient (low dose of ethanol). Vasorelaxant effect of EPA on pre-contracted isolated rings was more important than DHA at equivalent dose, and was dose- and endothelium-dependent. This effect involves NO production.Bolus DHEA perfusion in the pulmonary vascular bed study on instrumented fetal sheep highlighted an acute vasodilator effect. This effect was dose-dependent with a more pronounced and sustained decrease in PVR at highest doses of DHEA. Finally, mechanisms of action study found an inhibition of the effect of DHEA by the LNA, indicating that DHEA-induced vasodilation is NO dependant.Taken together, our results suggest that supplementation with ω-3 PUFAs and DHEA within the perinatal period may prevent BPD and PPHN in high risk conditions including preterm birth, premature rupture of the membrane or intrauterine growth restriction

    Lung liquid clearance in preterm lambs assessed by magnetic resonance imaging

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    International audienceBACKGROUND: Postnatal adaptation requires liquid clearance and lung aeration. However, their relative contribution to the expansion of functional residual capacity (FRC) has not been fully investigated. We studied evolution of lung liquid removal and lung aeration after birth in preterm lambs. METHODS: Lung liquid content and lung volume were assessed at birth and every 30 min over 2 h using magnetic resonance imaging (MRI) in three groups of lambs delivered by cesarean: preterm, late preterm, and late preterm with antenatal steroids. Lung function and mechanics of the respiratory system were also measured. RESULTS: Lung liquid content increased by approximately 30% in the preterm group (P < 0.05), whereas it did not change significantly in the late preterm lambs. Antenatal steroids induced a 50% drop in the lung liquid content (P < 0.05). Total lung volume increased in all groups (P < 0.05) but was higher in the late preterm + steroids group relative to other groups (P < 0.05). Compliance and resistances of the respiratory system were significantly correlated with lung liquid content (P < 0.05). CONCLUSION: FRC expansion results mainly from an increase in lung volume rather than a decrease in lung liquid in preterm and late preterm lambs. Antenatal steroids promote FRC expansion through increases in lung volume and liquid clearance

    Platelet-to-albumin ratio and radiation-induced lymphopenia—prognostic biomarker for carcinoma esophagus

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    Abstract Background Esophageal cancer has a poor survival outcome with 5-year OS at 16.7% despite treatment. Some inflammation-based prognostic indicators like the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been previously studied as potential biomarker for predicting outcome in esophageal cancer. Recently, platelet-to-albumin ratio (PAR) has been reported as a promising prognostic factor in gastrointestinal malignancies. Methods We performed a retrospective analysis of prospectively treated patients of carcinoma esophagus to evaluate the prognostic significance of inflammation-based prognostic indicators—neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and a composite inflammation-nutrition index: platelet-to-albumin ratio (PAR) in esophageal cancer. Based on previous studies, the optimal cut-off value of PAR was kept at 5.7 × 10^9, and 2.62 for NLR. Results A total of 71 patients of locally advanced esophageal cancer treated between 2019 and 2022, with either neoadjuvant or definitive chemoradiotherapy, were included. Median follow-up time was 19 months [range: 7–44 months]. Median OS and PFS in our study cohort were 11.3 months [range: 7–23 months] and 7.8 months [range: 3–17 months], respectively. In univariate analysis, lower PAR was found to be significantly correlated with shorter survival time (HR = 2.41; 1.3–4.76; p = 0.047). There was no association found between the OS and the NLR [HR = 1.09; 0.95–1.26; p = 0.222]. Univariate and multivariate linear and logistic regressions found no association between V15, V10, V5, or V2 of spleen and nadir lymphocyte count or between Dmax or Dmean and nadir lymphocyte counts. Conclusion Present analysis found a trend toward an inverse association between PAR and OS. PAR, in the not-so-distant future, may evolve as a novel, convenient, and inexpensive prognostic indicator in esophageal cancer

    Spatial analysis of hypospadias cases in northern France: taking clinical data into account

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    International audienceAbstract Background Strong evidence for a causal role of environmental factors in a congenital anomaly is still difficult to produce. The collection of statistical data is crucial for gaining a better understanding of the epidemiology and pathophysiology of these anomalies. We aimed to evaluate spatial variations in hypospadias within our region and it’s association to socioeconomic and ecological factors, taking clinical data into account. Methods All boys with hypospadias born in northern France and seen in Lille University Medical Center (Lille, France) between 1999 and 2012 were included in the analysis. We retrospectively collected geographic data, clinical data (especially known confounding factors associated with an elevated risk of hypospadias), and demographic, socio-economic and ecological data. We analyzed the entire study population and subsequently the subset of boys lacking confounding factors. Results The study sample of 975 cases of hypospadias over the 13-year period resulted in an incidence of 25.4/10,000 male births, and was characterized by significant spatial heterogeneity ( p < 0.005) and autocorrelation ( p < 0.001). We detected two high-incidence clusters that differed with regard to their land use. After the exclusion of 221 patients with confounding factors, two high-incidence clusters with significant disease risks (1.65 and 1.75, respectively; p < 0.001) and a significant difference in land use ( p < 0.001) again appeared. The first cluster contained a higher median [interquartile range] proportion of artificialized land (0.40 [0.22;0.47]) than the remaining “neutral areas” (0.19 [0.08;0.53]) did ( p < 0.001). Conversely, the second cluster contained a higher median proportion of rural land (0.90 [0.78;0.96]) than the “neutral areas” (0.81 [0.47;0.92]) did ( p < 0.001). The median deprivation index was significantly lower in the urban cluster (0.47 [0.42;0.55]) and significantly higher in the rural cluster (0.69 [0.56;0.73]) ( p < 0.001). Conclusions Our results evidenced the heterogeneous spatial distribution of cases of hypospadias in northern France. We identified two clusters with different environmental and social patterns – even after the exclusion of known confounding factors

    Effects of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) on Fetal Pulmonary Circulation: An Experimental Study in Fetal Lambs

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    Background: Persistent pulmonary hypertension of the newborn (PPHN) causes significant morbidity and mortality in neonates. n-3 Poly-unsaturated fatty acids have vasodilatory properties in the perinatal lung. We studied the circulatory effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in fetal sheep and in fetal pulmonary arterial rings. Methods: At 128 days of gestation, catheters were placed surgically in fetal systemic and pulmonary circulation, and a Doppler probe around the left pulmonary artery (LPA). Pulmonary arterial pressure and LPA flow were measured while infusing EPA or DHA for 120 min to the fetus, to compute pulmonary vascular resistance (PVR). The dose effects of EPA or DHA were studied in vascular rings pre-constricted with serotonin. Rings treated with EPA were separated into three groups: E+ (intact endothelium), E− (endothelium stripped) and LNA E+ (pretreatment of E+ rings with l-nitro-arginine). Results: EPA, but not DHA, induced a significant and prolonged 25% drop in PVR (n = 8, p &lt; 0.001). Incubation of vascular rings with EPA (100 ”M) caused a maximum relaxation of 60% in the E+ (n = 6), whereas vessel tone did not change in the E− (n = 6, p &lt; 0.001). The vascular effects of EPA were significantly decreased in LNA E+ (n = 6). Incubation with DHA resulted in only a mild relaxation at the highest concentration of DHA (300 ”M) compared to E+. Conclusions: EPA induces a sustained pulmonary vasodilatation in fetal lambs. This effect is endothelium- and dose-dependent and involves nitric oxide (NO) production. We speculate that EPA supplementation may improve pulmonary circulation in clinical conditions with PPHN

    Fetal brain response to worsening acidosis: an experimental study in a fetal sheep model of umbilical cord occlusions

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    Abstract Perinatal anoxia remains an important public health problem as it can lead to hypoxic–ischaemic encephalopathy (HIE) and cause significant neonatal mortality and morbidity. The mechanisms of the fetal brain’s response to hypoxia are still unclear and current methods of in utero HIE prediction are not reliable. In this study, we directly analysed the brain response to hypoxia in fetal sheep using in utero EEG. Near-term fetal sheep were subjected to progressive hypoxia induced by repeated umbilical cord occlusions (UCO) at increasing frequency. EEG changes during and between UCO were analysed visually and quantitatively, and related with gasometric and haemodynamic data. EEG signal was suppressed during occlusions and progressively slowed between occlusions with the increasing severity of the occlusions. Per-occlusion EEG suppression correlated with per-occlusion bradycardia and increased blood pressure, whereas EEG slowing and amplitude decreases correlated with arterial hypotension and respiratory acidosis. The suppression of the EEG signal during cord occlusion, in parallel with cardiovascular adaptation could correspond to a rapid cerebral adaptation mechanism that may have a neuroprotective role. The progressive alteration of the signal with the severity of the occlusions would rather reflect the cerebral hypoperfusion due to the failure of the cardiovascular adaptation mechanisms
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