Sarah Valentino

A perspective on the developmental toxicity of inhaled nanoparticles

This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.

Placental structure and function in different breeds in horses

Ponies and sometimes draft horses are often used as experimental models for horses although size and metabolic parameters are known to vary between horse breeds. So far, there is little information about differences of placental structure and no information about differences of placental function between breeds. The aim of this study was to investigate differences in placental size, structure and function at birth in relation to foal size and weight in ponies, Saddlebred and draft horses. Pony, Saddlebred and draft horse pregnancies were obtained by artificial insemination over 2 successive breeding seasons. Foals and total fetal membranes (TFM) were weighed and placentas measured for surface area at term. Placentas were sampled above the umbilical cord insertion. Surface density and volume fraction of the different cellular components of the placenta were measured on histological sections using stereology. The expression of genes involved in growth and development, nutrient transfer and vascularization was compared between groups. Foals and TFM were lighter at birth in ponies than Saddlebred horses, and both were lighter compared to draft horses. The surface density and volume fraction of microcotyledonary vessels was increased in pony compared to Saddlebred placentas. The relative expression of genes involved in growth and development was different between breeds and increased with maternal, fetal and placental weight. Primiparous dams produced lighter foals and smaller placentas, associated with a decreased volume fraction of microcotyledonary vessels and genes involved in growth and development and vascularization. Foal sex had little effect on placental structure and function as the expression of only one gene differed according to sex, with EGFR expression being decreased in placentas of females compared to males. In conclusion, foal and placental weight, as well as placental expression of genes involved in growth and development were correlated with maternal size. Placental structure also differed between breeds, with a stronger difference between ponies and both breeds of horses.

Exposition aux gaz d'échappement diesel durant la gestation: quelles conséquences sur le développement fœto-placentaire? Apport des modèles animaux

La pollution atmosphérique est un problème majeur pour la santé humaine, causant 3,7 millions de décès prématurés en 2012 dans le monde. Les personnes âgées, les enfants ou les asthmatiques sont les cibles des messages de prévention lors de pics de pollution alors que les femmes enceintes sont le plus souvent négligées. Pourtant, les études épidémiologiques et les travaux sur les modèles animaux indiquent que la pollution atmosphérique et ses composants peuvent perturber la fonction placentaire, réduire la croissance fœtale et induire un stress oxydant et une inflammation. A long terme, ces effets peuvent participer à l’augmentation des risques de maladies métaboliques chez l’adulte. Il est donc important d’inclure les femmes enceintes dans les messages de prévention lors de pics de pollution atmosphérique et de continuer la recherche sur les effets à long terme grâce au recours aux modèles animaux.