The role of maternal exercise on placental, behavioral and genetic alterations induced by prenatal stress

A "toxic window" study on the hippocampal development of mice offspring exposed to azithromycin at different doses, courses, and time during pregnancy

BACKGROUND

Azithromycin, one of the new-generation macrolides, is an effective medicine for the treatment of mycoplasma infection during pregnancy. Epidemiological studies have reported adverse pregnancy outcomes with prenatal azithromycin exposure (PAzE). However, the effect of PAzE on fetal hippocampal development is unclear. This study aimed to explore the effects and potential mechanism of PAzE-induced fetal hippocampal development at different doses, courses, and time.

METHOD

Pregnant mice were administered azithromycin by gavage at different doses (50, 100 or 200 mg/kg.d), different courses (gestational day (GD)15-17 for three consecutive days, or GD17 once a day) and different time (GD10-12, GD15-17).

RESULTS

Compared with the control group, morphological development damage of the fetal hippocampus was observed in the PAzE group, with a dysbalance in neuronal proliferation and apoptosis, decreased expression of the neuronal-specific marker Snap25, NeuN, PSD95 and Map2, increased expression of the glial-specific marker Iba1, GFAP, and S-100β, and decreased expression of P2ry12. The PAzE-induced hippocampal developmental deficiency varied based on different doses, courses, and time, and the developmental toxicity was most significant in the late pregnancy, high dose, multi-course group (AZHT). The significant reduction of SOX2 and Wnt, which were related to regulation of neural progenitor cells (NPCs) proliferation in PAzE fetus compared with the control group indicated that the SOX2/Wnt signaling may be involved in PAzE-induced hippocampal developmental toxicity.

CONCLUSION

In this study, PAzE was associated with hippocampal developmental toxicity in a variety of nerve cells. Hippocampal developmental toxicity due to azithromycin was most significant in the late pregnancy, high-dose (equivalent to maximum clinical dose) and multi-course group (AZHT). The findings provide an experimental and theoretical foundation for guiding the sensible use of medications during pregnancy and effectively assessing the risk of fetal hippocampal developmental toxicity.

Oxytocin: A developmental journey

The neuropeptide hormone oxytocin is involved in many processes in our bodies, linking our social lives to our internal states. I started out my career studying primate families, an interest that expanded into the role of oxytocin in family-oriented behaviors such as pair bonding and parenting in prairie voles, humans, and other primates. Starting as a post-doc with Dr. C. Sue Carter, I also became interested in the role of oxytocin during development and the way that we manipulate oxytocin clinically. During that post-doc and then as a faculty member at the University of California, Davis, I have worked on a number of these questions.

Molecular mechanisms underlying physical exercise-induced brain BDNF overproduction

Accumulating evidence supports that physical exercise (EX) is the most effective non-pharmacological strategy to improve brain health. EX prevents cognitive decline associated with age and decreases the risk of developing neurodegenerative diseases and psychiatric disorders. These positive effects of EX can be attributed to an increase in neurogenesis and neuroplastic processes, leading to learning and memory improvement. At the molecular level, there is a solid consensus to involve the neurotrophin brain-derived neurotrophic factor (BDNF) as the crucial molecule for positive EX effects on the brain. However, even though EX incontestably leads to beneficial processes through BDNF expression, cellular sources and molecular mechanisms underlying EX-induced cerebral BDNF overproduction are still being elucidated. In this context, the present review offers a summary of the different molecular mechanisms involved in brain's response to EX, with a specific focus on BDNF. It aims to provide a cohesive overview of the three main mechanisms leading to EX-induced brain BDNF production: the neuronal-dependent overexpression, the elevation of cerebral blood flow (hemodynamic hypothesis), and the exerkine signaling emanating from peripheral tissues (humoral response). By shedding light on these intricate pathways, this review seeks to contribute to the ongoing elucidation of the relationship between EX and cerebral BDNF expression, offering valuable insights into the potential therapeutic implications for brain health enhancement.

Influence of a concurrent exercise training program during pregnancy on the placenta mitochondrial DNA integrity and content of minerals with enzymatic relevance. The GESTAFIT project

INTRODUCTION

We aimed i) to investigate the effects of a concurrent (aerobic plus strength) exercise intervention during pregnancy on placental mtDNA copy number, proportion of deleted mtDNA, and on the content of some trace and ultra-trace minerals with coenzymatic relevance; ii) to explore the association of such mitochondrial markers with the concentration of these minerals.

METHODS

For the present study specific aims, 47 placentas were randomly selected from women that participated in the GESTAFIT project into exercise (n = 24) or control (n = 23) groups. The exercise group followed a concurrent aerobic and strength training program, three 60-min sessions/week, from the 17th gestational week until birth. Placenta tissue was collected and processed for minerals determination by the inductively coupled plasma mass spectrometry technique. RT-PCR was used to determine placentas mtDNA copy number and ND1/ND4 deletion.

RESULTS

After adjusting for potential confounders, the mothers who participated in the exercise program had placentas with greater mtDNA copy number (p = 0.04) and lower mtDNA deletion (p = 0.003). Placentas from mothers in the exercise group presented higher manganese content than those from the controls (0.26 ± 0.03 mg/dL vs. 0.13 ± 0.03 mg/dL, p = 0.003). Placenta manganese content was significantly associated with lower mtDNA deletions (r = -0.382) and greater mtDNA copy number (r = 0.513). Iron content was associated with higher mtDNA copy number (r = 0.393). Selenium content was associated with lower mtDNA deletion (r = -0.377) and greater mtDNA copy number (r = 0.442). Finally, zinc and magnesium content were associated with higher mtDNA copy number (r = 0.447 and r = 0.453, respectively).

DISCUSSION

This concurrent exercise training program induced a better placental status, which might be mediated through an improvement of mitochondrial bioenergetics and antioxidative capacity.

BDNF and KISS-1 Levels in Maternal Serum, Umbilical Cord, and Placenta: The Potential Role of Maternal Levels as Effect Biomarker

Brain-derived neurotrophic factor (BDNF) and kisspeptin-1 (KISS-1) regulate placental development and fetal growth. The predictive value of maternal serum BDNF and KISS-1 concentrations for placental and umbilical cord levels has not yet been explored. The influence of prenatal lead (Pb) and cadmium (Cd) exposure and maternal iron status on BDNF and KISS-1 levels is also unclarified and of concern. In a pilot cross-sectional study with 65 mother-newborn pairs, we analyzed maternal and cord serum levels of pro-BDNF, mature BDNF, and KISS-1, BDNF, and KISS-1 gene expression in placenta, Pb and Cd in maternal and umbilical cord blood (erythrocytes), and placenta. We conducted a series of in vitro experiments using human primary trophoblast cells (hTCs) and BeWo cells to verify main findings of the epidemiological analysis. Strong and consistent correlations were observed between maternal serum levels of pro-BDNF, mature BDNF, and KISS-1 and corresponding levels in umbilical serum and placental tissue. Maternal red blood cell Pb levels were inversely correlated with serum and placental KISS-1 levels. Lower expression and release of KISS-1 was also observed in Pb-exposed BeWo cells. In vitro Pb exposure also reduced cellular BDNF levels. Cd-treated BeWo cells showed increased pro-BDNF levels. Low maternal iron status was positively associated with low BDNF levels. Iron-deficient hTCs and BeWo cells showed a consistent decrease in the release of mature BDNF. The correlations between maternal BDNF and KISS-1 levels, placental gene expression, and umbilical cord serum levels, respectively, indicate the strong potential of maternal serum as predictive matrix for BDNF and KISS-1 levels in placentas and fetal sera. Pb exposure and iron status modulate BDNF and KISS-1 levels, but a clear direction of modulations was not evident. The associations need to be confirmed in a larger sample and validated in terms of placental and neurodevelopmental function.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12403-023-00565-w.

Resistance exercise was safe for the pregnancy and offspring's development and partially protected rats against early life stress-induced effects

Promising evidence points to gestational physical exercise as the key to preventing various disorders that affect the offspring neurodevelopment, but there are no studies showing the impact of resistance exercise on offspring health. Thus, the aim of this study was to investigate whether resistance exercise during pregnancy is able to prevent or to alleviate the possible deleterious effects on offspring, caused by early life-stress (ELS). Pregnant rats performed resistance exercise throughout the gestational period:they climbed a sloping ladder with a weight attached to their tail, 3 times a week. Male and female pups, on the day of birth (P0), were divided into 4 experimental groups: 1) rats of sedentary mothers (SED group); 2) rats of exercised mothers (EXE group); 3) rats of sedentary mothers and submitted to maternal separation (ELS group) and 4) rats of exercised mothers and submitted to MS (EXE + ELS group). From P1 to P10, pups from groups 3 and 4 were separated from their mothers for 3 h/day. Maternal behavior was assessed. From P30, behavioral tests were performed and on P38 the animals were euthanized and prefrontal cortex samples were collected. Oxidative stress and tissue damage analysis by Nissl staining were performed. Our results demonstrate that male rats are more susceptible to ELS than females, showing impulsive and hyperactive behavior similar to that seen in children with ADHD. This behavior was attenuated by the gestational resistance exercise. Our results demonstrate, for the first time, that resistance exercise performed during pregnancy seems to be safe for the pregnancy and offspring's neurodevelopment and are effective in preventing ELS-induced damage only in male rats. Interestingly, resistance exercise during pregnancy improved maternal care and it is reasonable to propose that this finding may be related to the protective role on the animals neurodevelopment, observed in our study.

Severe maternal stress alters placental function, resulting in adipose tissue and liver dysfunction in offspring of mice

The developmental origins of health and disease (DOHaD) hypothesis is that future lifestyle diseases in offspring are associated with intrauterine origins in the mother; stress during pregnancy is a risk factor for these diseases in offspring. This study aimed to clarify association of maternal stress with placental dysfunction and offspring development in mice. We applied water stress for 24 h during late pregnancy to explore the metabolic response of offspring to a normal diet (ND) and high-fat diet (HFD). Placental functions were altered by maternal stress, reducing the birth weight of the offspring. In the later life of offspring fed with ND, maternal stress impaired systemic glucose tolerance and altered adipokine secretion in adipose tissue and/or liver. The female offspring of stress-induced dams were light in body weight with lower adipose tissue and smaller adipocytes in both the ND and HFD groups. Abnormal situations, such as dysregulation of plasma glucose levels and fatty liver despite and lower increases in body weight, were observed in the female offspring of stress-induced dams, especially in the HFD-treated group. These findings suggest that long-lasting abnormal conditions and responses to metabolic challenges in maternal stress-induced offspring are linked to placental dysregulation and fetal programming.