The effects of perinatal steroid therapy on growth factor levels during different stages of the developing brain

Reproductive outcomes of neonatal exposure to betamethasone in male and female rats

Betamethasone (BM) is the drug of choice for antenatal corticosteroid therapy for women at risk of preterm delivery because it induces fetal lung maturation and enhances survival after birth. However, our group reported evidence of fetal programming and impaired reproductive development and function in rats exposed during the critical window of genital system development. Therefore, we aimed to investigate the effects of BM on the sexual development of rats in the period that corresponds to antenatal corticosteroid therapy in humans. Male and female rats were exposed subcutaneously to BM at 0.1 μg/g of pups' body weight or to a NaCl 0.9% solution (control) on postnatal days 1-3. It was observed that neonatal exposure to BM decreased body weight and weight gain in male and female rats during treatment. The estrous cycle was deregulated and LH level was decreased in female rats. In male rats, the sperm concentration in the caput-corpus of the epididymis was decreased, whereas the sperm transit time and sperm concentration in the cauda of the epididymis were increased. Our results demonstrated that neonatal exposure to BM impaired body growth of male and female rats, deregulated the estrous cycle of female rats, and altered sperm quality of male rats. Therefore, BM exposure from postnatal days 1 to 3 corroborated results previously observed after prenatal exposure to this drug. Despite the recognized importance of human antenatal corticosteroid therapy, the findings of this study should encourage further studies in order to minimize possible adverse postnatal effects.

Regional microstructural organization of the cerebral cortex is affected by preterm birth

Objectives

To compare regional cerebral cortical microstructural organization between preterm infants at term-equivalent age (TEA) and healthy full-term newborns, and to examine the impact of clinical risk factors on cerebral cortical micro-organization in the preterm cohort.

Study design

We prospectively enrolled very preterm infants (gestational age (GA) at birth<32 weeks; birthweight<1500 g) and healthy full-term controls. Using non-invasive 3T diffusion tensor imaging (DTI) metrics, we quantified regional micro-organization in ten cerebral cortical areas: medial/dorsolateral prefrontal cortex, anterior/posterior cingulate cortex, insula, posterior parietal cortex, motor/somatosensory/auditory/visual cortex. ANCOVA analyses were performed controlling for sex and postmenstrual age at MRI.

Results

We studied 91 preterm infants at TEA and 69 full-term controls. Preterm infants demonstrated significantly higher diffusivity in the prefrontal, parietal, motor, somatosensory, and visual cortices suggesting delayed maturation of these cortical areas. Additionally, postnatal hydrocortisone treatment was related to accelerated microstructural organization in the prefrontal and somatosensory cortices.

Conclusions

Preterm birth alters regional microstructural organization of the cerebral cortex in both neurocognitive brain regions and areas with primary sensory/motor functions. We also report for the first time a potential protective effect of postnatal hydrocortisone administration on cerebral cortical development in preterm infants.