Teratogenesis and the epigenetic programming of congenital defects: Why paternal exposures matter

Preconception Paternal Alcohol Consumption Elicits Postnatal Changes in Neural Retinas of the Offspring

Purpose

This study aims to determine the impact of preconception paternal alcohol consumption (PPAC) on retinal function and morphology in PPAC-offspring. Fetal alcohol spectrum disorder (FASD)-related ocular defects caused by maternal alcohol exposure has been well investigated, but the influence of PPAC on offspring eyes remains unknown.

Methods

Adult C57BL/6J male mice were exposed to either 10% ethanol or water (control) for six weeks and bred to naïve females. Dark-adapted retinal light responses at two, four, and six months old were assessed using electroretinography (ERG) for the offspring born to PPAC and control males. The thicknesses of whole retinas and different retinal layers of the control and PPAC-offspring were analyzed at two and six months old.

Results

Some PPAC-offspring had only one developed eye. ERG a- and b-wave amplitudes were reduced in PPAC-offspring compared to controls, with a more pronounced effect in females. PPAC had significant effects on inner retinal function. At two months old, there was a significant thinning of the retinal inner nuclear and inner plexiform layers in PPAC-offspring. At six months old, the retinal thickness and ERG amplitudes were similar between both treatment groups.

Conclusions

This study provides pioneering evidence that PPAC contributes to FASD-related ocular defects including negative impacts on retinal light responses and retinal thinning in young adult offspring. Thus the adverse impact of paternal alcohol consumption prior to conception on their offspring (from childhood to early adulthood) should be considered as seriously as the maternal contribution to FASD.

Paternal exposure to antiseizure medications and offspring outcomes: a systematic review

BACKGROUND

Concerns have recently been raised about risks to the fetus resulting from paternal exposure to antiseizure medications (ASMs). To address these concerns, we conducted a systematic review of the literature to assess neurodevelopmental and anatomical outcomes in offspring born to fathers taking ASMs at the time of conception.

METHODS

Electronic searches of MEDLINE, PsycINFO, and Embase were conducted to identify human studies published in English that reported on outcomes, comprising neurodevelopmental disorders, major congenital malformations, small-for-gestational age or low birth weight, in offspring of fathers taking ASMs at conception. Quality analysis of included studies was undertaken using the Newcastle-Ottawa Scale. A narrative synthesis was used to report study findings.

RESULTS

Of 923 studies identified by the search and screened by title and abstract, 26 underwent full-text review and 10 met eligibility criteria. There was limited evidence available, but there appeared to be no clear evidence for an adverse impact of paternal ASM use on offspring outcomes. Few isolated adverse findings were not replicated by other investigations. Several methodological limitations prevented meta-analysis, including failure by most studies to report outcomes separately for each individual ASM, heterogeneity in measurement and outcome reporting, and small numbers of monotherapy exposures.

CONCLUSIONS

Although there were limited data available, this systematic review provides reassuring evidence that paternal exposure to ASMs at conception is unlikely to pose any major risk of adverse outcomes for the offspring. Further research is needed to examine the relationship between preconception ASM use in males and offspring outcomes at birth and postnatally.

Parental Alcohol Exposures Associate with Lasting Mitochondrial Dysfunction and Accelerated Aging in a Mouse Model

Although detrimental changes in mitochondrial morphology and function are widely described symptoms of fetal alcohol exposure, no studies have followed these mitochondrial deficits into adult life or determined if they predispose individuals with fetal alcohol spectrum disorders (FASDs) to accelerated biological aging. Here, we used a multiplex preclinical mouse model to compare markers of cellular senescence and age-related outcomes induced by maternal, paternal, and dual-parental alcohol exposures. We find that even in middle life (postnatal day 300), the adult offspring of alcohol-exposed parents exhibited significant increases in markers of stress-induced premature cellular senescence in the brain and liver, including an upregulation of cell cycle inhibitory proteins and increased senescence-associated β-galactosidase activity. Strikingly, in the male offspring, we observe an interaction between maternal and paternal alcohol use, with histological indicators of accelerated age-related liver disease in the dual-parental offspring exceeding those induced by either maternal or paternal alcohol use alone. Our studies indicate that chronic parental alcohol use causes enduring mitochondrial dysfunction in offspring, resulting in a reduced NAD+/NAHD ratio and altered expression of the NAD+-dependent deacetylases SIRT1 and SIRT3. These observations suggest that some aspects of FASDs may be linked to accelerated aging due to programmed changes in the regulation of mitochondrial function and cellular bioenergetics.

Association between Maternal Birth Weight and Prevalence of Congenital Malformations in Offspring: The Japanese Environment and Children's Study

Congenital malformations are functional and structural alterations in embryonic or foetal development resulting from a variety of factors including maternal health status. This study aimed to investigate the association between maternal birth weight (MBW) and the prevalence of congenital malformations in offspring using data from a nationwide birth cohort study in Japan including 103,060 pregnancies. A binary logistic regression model with adjustment for various covariates revealed that an MBW of <2500 g (low MBW) was associated with an increased risk of congenital heart disease (adjusted odds ratio: 1.388, [95% confidence interval: 1.075-1.792]), angioma (1.491 [1.079-2.059]), and inguinal hernia (1.746, [1.189-2.565]), while those with an MBW of ≥4000 g (high MBW) were associated with congenital anomalies of the urinary tract (2.194, [1.261-3.819]) and arrhythmia (1.775, [1.157-2.725]) compared with those with an MBW of 3000-3499 g. Low MBW was associated with cleft lip and/or palate (1.473, [1.052-2.064]), congenital heart disease (1.615, [1.119-2.332]), genital organs (1.648, [1.130-2.405]), hypospadias (1.804, [1.130-2.881]), and inguinal hernia (1.484, [1.189-1.851]) in male infants and CAKUT (1.619, [1.154-2.273]) in female infants, whereas high MBW was associated with congenital heart disease (1.745, [1.058-2.877]) and CAKUT (2.470, [1.350-4.517]) in male infants. The present study is the first to demonstrate a link between MBW and congenital malformations in Japanese children. While these results must be interpreted with caution, MBW should be considered a major predictor of congenital malformation risk.

Paternal p,p'-DDE exposure and pre-pubertal high-fat diet increases the susceptibility to fertility impairment and sperm Igf2 DMR2 hypo-methylation in male offspring

The hypothesis of paternal origins of health and disease (POHaD) indicates that paternal exposure to adverse environment could alter the epigenetic modification in germ line, increasing the disease susceptibility in offspring or even in subsequent generations. p,p'-Dichlorodiphenyldichloroethylene (p,p'-DDE) is an anti-androgenic chemical and male reproductive toxicant. Gestational p,p'-DDE exposure could impair reproductive development and fertility in male offspring. However, the effect of paternal p,p'-DDE exposure on fertility in male offspring remains uncovered. From postnatal day (PND) 35 to 119, male rats (F0) were given 10 mg/body weight (b.w.) p,p'-DDE or corn oil by gavage. Male rats were then mated with the control females to generate male offspring. On PND35, the male offspring were divided into 4 groups according whether to be given the high-fat diet (HF): corn oil treatment with control diet (C-C), p,p'-DDE treatment with control diet (DDE-C), corn oil treatment with high-fat diet (C-HF) or p,p'-DDE treatment with high-fat diet (DDE-HF) for 35 days. Our results indicated that paternal p,p'-DDE exposure did not affect the male fertility of male offspring directly, but decreased sperm quality and induced testicular apoptosis after the high-fat diet treatment. Further analysis demonstrated that paternal exposure to p,p'-DDE and pre-pubertal high-fat diet decreased sperm Igf2 DMR2 methylation and gene expression in male offspring. Hence, paternal exposure to p,p'-DDE and pre-pubertal high-fat diet increases the susceptibility to male fertility impairment and sperm Igf2 DMR2 hypo-methylation in male offspring, posing a significant implication in the disease etiology.