Proteomic Signatures in Spermatozoa Reveal the Role of Paternal Factors in Recurrent Pregnancy Loss

Purpose

To identify the paternal factors responsible for aberrant embryo development leading to loss of foetus in recurrent pregnancy loss (RPL) through proteomic analysis of ejaculated spermatozoa.

Materials and Methods

This prospective study consisted of male partners of RPL patients (n=16) experienced with two or more consecutive unexplained miscarriages and with no female factor abnormality as revealed by gynaecologic investigation including karyotyping and age matched fertile healthy volunteers (n=20). All samples were collected during 2013 to 2015 after getting institutional ethical approval and written consent from the participants. Seminal ejaculates were collected by masturbation after 2 to 3 days of sexual abstinence and analyzed according to World Health Organization 5th criteria 2010. Two-dimensional difference gel electrophoresis followed by mass spectrophotometric analysis was used to identify differentially expressed proteins (DEPs). Western blotting was used for validation of the key proteins.

Results

The data identified 36 protein spots to be differentially expressed by more than 2-fold change with p<0.05 considered as significant. Matrix-assisted laser desorption/ionization time of flight/mass spectrometry identified GPx4, JIP4, ZN248 to be overexpressed while HSPA2, GSTM5, TF3C1, CC74A was underexpressed in RPL group. Western blot analysis confirmed the differential expression of key redox associated proteins GPx4 and HSPA2 in the RPL group. Functional analysis revealed the involvement of key biological processes that includes spermatogenesis, response to oxidative stress, protein folding and metabolic process.

Conclusions

The present study provides a snapshot of the altered protein expression levels consistent with the potential involvement of the sperm chromatin landscape in early embryonic development.

Paternal factors contributing to embryo quality

PURPOSE

Advancing maternal and paternal age leads to a decrease in fertility, and hence, many infertile couples opt for assisted reproductive technologies [ART] to achieve biological parenthood. One of the key determinants of achieving a live outcome of ART, embryo quality, depends on both the quality of the oocyte and sperm that have created the embryo. Several studies have explored the effect of oocyte parameters on embryo quality, but the effects of sperm quality on the embryo have not been comprehensively evaluated.

METHOD

In this review, we assess the effect of various genetic factors of paternal origin on the quality and development of the embryo.

RESULTS

The effects of sperm aneuploidy, sperm chromatin structure, deoxyribonucleic acid [DNA] fragmentation, role of protamines and histones, sperm epigenetic profile, and Y chromosome microdeletions were explored and found to negatively affect embryo quality.

CONCLUSION

We propose that careful assessment of spermatozoal parameters is essential to achieve embryo development and a healthy live birth. However, the heterogeneity in test results and the different approaches of assessing a single sperm parameter highlight the need for more research and the development of standardized protocols to assess the role of sperm factors affecting embryo quality.

Maternal Exposure to Childhood Abuse is Associated with Mate Selection: Implications for Autism in Offspring

Maternal experience of childhood abuse has been associated with offspring autism. To explore whether familial tendency towards autistic traits-presumably related to genetic predisposition-accounts for this association, we examined whether women who experienced childhood abuse were more likely to select mates with high levels of autistic traits, and whether parental autistic traits accounted for the association of maternal abuse and offspring autism in 209 autism cases and 833 controls. Maternal childhood abuse was strongly associated with high paternal autistic traits (severe abuse, OR = 3.98, 95% CI = 1.26, 8.31). Maternal and paternal autistic traits accounted for 21% of the association between maternal abuse and offspring autism. These results provide evidence that childhood abuse affects mate selection, with implications for offspring health.

Association of missing paternal demographics on infant birth certificates with perinatal risk factors for childhood obesity

BACKGROUND

The role of fathers in the development of obesity in their offspring remains poorly understood. We evaluated associations of missing paternal demographic information on birth certificates with perinatal risk factors for childhood obesity.

METHODS

Data were from the Linked CENTURY Study, a database linking birth certificate and well-child visit data for 200,258 Massachusetts children from 1980-2008. We categorized participants based on the availability of paternal age, education, or race/ethnicity and maternal marital status on the birth certificate: (1) pregnancies missing paternal data; (2) pregnancies involving unmarried women with paternal data; and (3) pregnancies involving married women with paternal data. Using linear and logistic regression, we compared differences in smoking during pregnancy, gestational diabetes, birthweight, breastfeeding initiation, and ever recording a weight for length (WFL) ≥ the 95th percentile or crossing upwards ≥2 WFL percentiles between 0-24 months among the study groups.

RESULTS

11,989 (6.0 %) birth certificates were missing paternal data; 31,323 (15.6 %) mothers were unmarried. In adjusted analyses, missing paternal data was associated with lower birthweight (β -0.07 kg; 95 % CI: -0.08, -0.05), smoking during pregnancy (AOR 4.40; 95 % CI: 3.97, 4.87), non-initiation of breastfeeding (AOR 0.39; 95 % CI: 0.36, 0.42), and with ever having a WFL ≥ 95th percentile (AOR 1.10; 95 % CI: 1.01, 1.20). Similar associations were noted for pregnancies involving unmarried women with paternal data, but differences were less pronounced.

CONCLUSIONS

Missing paternal data on the birth certificate is associated with perinatal risk factors for childhood obesity. Efforts to understand and reduce obesity risk factors in early life may need to consider paternal factors.