In Vivo Evaluation of Cervical Stiffness Evolution during Induced Ripening Using Shear Wave Elastography, Histology and 2 Photon Excitation Microscopy: Insight from an Animal Model

Prematurity affects 11% of the births and is the main cause of infant mortality. On the opposite case, the failure of induction of parturition in the case of delayed spontaneous birth is associated with fetal suffering. Both conditions are associated with precocious and/or delayed cervical ripening. Quantitative and objective information about the temporal evolution of the cervical ripening may provide a complementary method to identify cases at risk of preterm delivery and to assess the likelihood of successful induction of labour. In this study, the cervical stiffness was measured in vivo in pregnant sheep by using Shear Wave Elastography (SWE). This technique assesses the stiffness of tissue through the measurement of shear waves speed (SWS). In the present study, 9 pregnant ewes were used. Cervical ripening was induced at 127 days of pregnancy (term: 145 days) by dexamethasone injection in 5 animals, while 4 animals were used as control. Elastographic images of the cervix were obtained by two independent operators every 4 hours during 24 hours after injection to monitor the cervical maturation induced by the dexamethasone. Based on the measurements of SWS during vaginal ultrasound examination, the stiffness in the second ring of the cervix was quantified over a circular region of interest of 5 mm diameter. SWS was found to decrease significantly in the first 4–8 hours after dexamethasone compared to controls, which was associated with cervical ripening induced by dexamethasone (from 1.779 m/s ± 0.548 m/s, p < 0.0005, to 1.291 m/s ± 0.516 m/s, p < 0.000). Consequently a drop in the cervical elasticity was quantified too (from 9.5 kPa ± 0.9 kPa, p < 0.0005, to 5.0 kPa ± 0.8 kPa, p < 0.000). Moreover, SWE measurements were highly reproducible between both operators at all times. Cervical ripening induced by dexamethasone was confirmed by the significant increase in maternal plasma Prostaglandin E2 (PGE2), as evidenced by the assay of its metabolite PGEM. Histological analyses and two-photon excitation microscopy, combining both Second Harmonic Generation (SHG) and Two-photon Fluorescence microscopy (2PF) contrasts, were used to investigate, at the microscopic scale, the structure of cervical tissue. Results show that both collagen and 2PF-active fibrillar structures could be closely related to the mechanical properties of cervical tissue that are perceptible in elastography. In conclusion, SWE may be a valuable method to objectively quantify the cervical stiffness and as a complementary diagnostic tool for preterm birth and for labour induction success

L'Eléphant d'Asie (Elephas maximus) en Inde

LYON1-BU Santé (693882101) / SudocPARIS-Museum-Bib zoologie mam. (751052312) / SudocSudocFranceF

Mise au point d’un modèle de retard de croissance inra-utérin par restriction chirurgicale de la vascularisation utéro-placentaire chez la lapine

National audienc

Intergenerational effects of a maternal high fat diet on feto-placental development in a rabbit model

National audienc

Intergenerational effects of a maternal high fat diet on feto-placental development in a rabbit model

International audienceWe have shown that the maternal administration of a high fat diet (H) in a rabbit model, before and during pregnancy, induces sex-dependent metabolic adaptations in the placenta from F1 generation. Here, we have focused on the consequences of this diet on the fetal biometry and placental gene expression in the F2 offspring. Rabbit females were fed with a control diet (C) or H diet from 10 weeks of age throughout pregnancy and lactation. After weaning, the female offspring (F1) received either a C diet (groups CC and HC) or an H diet (groups CH and HH). They were mated at 18 weeks of age. At 28 days of gestation, the fetuses (F2) and their placentas were collected. The fetal weight and the fetal to placenta-deciduas weight ratio were significantly lower in HH and CH compared to CC, whereas they increased in HC compared to CH. Relative gene expression of lipid metabolism indicated that FATP-4 mRNA was significantly higher in HC compared to CC. SLC2A1 mRNA, a glucose transporter, was significantly increased in HH compared to the other groups, whereas SLC2A3 expression was higher in CH compared to CC, HC and HH groups. SLC38A1 and SLC38A2, which are involved in the transfer of amino acids, were significantly higher in HC compared to CC. Moreover, SLC38A2 was increased in CH compared to CC. These data established that the grandmother’s and the mother’s diets interfered to disrupt nutrient exchanges in the placenta from the F2 generation

Non-invasive evaluation of placental blood flow: lessons from animal models

In human obstetrics, placental vascularisation impairment is frequent as well as linked to severe pathological events (preeclampsia and intrauterine growth restriction), and there is a need for reliable methods allowing non-invasive evaluation of placental blood flow. Uteroplacental vascularisation is complex, and animal models are essential for the technical development and safety assessment of these imaging tools for human clinical use; however, these techniques can also be applied in the veterinary context. This paper reviews how ultrasound-based imaging methods such as 2D and 3D Doppler can provide valuable insight for the exploration of placental blood flow both in humans and animals and how new approaches such as the use of ultrasound contrast agents or ultrafast Doppler may allow to discriminate between maternal (non-pulsatile) and foetal (pulsatile) blood flow in the placenta. Finally, functional magnetic resonance imaging could also be used to evaluate placental blood flow, as indicated by studies in animal models, but its safety in human pregnancy still requires to be confirmed

Evaluation de la perfusion placentaire en IRM : variation des mesures de T2* chez un modèle lapin d’hypoperfusion placentaire aiguë

Thème de l'année 2017:" De l'implantation à la parturition: Bases fondamentales et cliniques"Evaluation de la perfusion placentaire en IRM : variation des mesures de T2* chez un modèle lapin d’hypoperfusion placentaire aiguë. 6. Colloque International du Groupe de la Francophonie Placentair