ORF47-05 - Slower Male Pubertal Trajectory Is Associated with Elevated Serum FSH Level, Decreased Testicular Volume and Fat-Free Mass, Altered Semen Quality and Sperm Epigenetic Markers in Young Adulthood

Objectives.
We tracked the development of boys annually through puberty in a unique prospective cohort Russian Children’s Study (RCS). We investigated whether an pubertal trajectory could predict overall and reproductive health in young adulthood, and what sperm epigenetic markers are associated with this process.
Methods.
We used group-based trajectory models (GBTMs) to identify subgroups of 489 boys who followed similar pubertal trajectories from ages 8–19 years based on annual volume of largest testis (TV) assessed by Prader orchidometer. Each boy was assigned to a single pubertal progression trajectory based on his highest posterior probability from the selected model. Semen samples from 217 subjects were collected at 18-19 years and evaluated according to WHO manual, 6th edition. Anthropometric, sexual maturity metrics and body composition indices assessed by Tanita BC-418MA were collected on the day of semen collection. Serum hormone levels (testosterone (T), SHBG, LH, FSH, prolactin (P), TSH and free T4) were analyzed by Architect i1000SR at the day of semen collection. Intra-assay CVs for hormones ranged 1.6-5%. A subset of 51 subjects and their ejaculate samples were selected for assessment of sperm DNA methylation using RRBS and small non-coding RNA using RNA-seq. Wilcoxon rank-sum test and univariate and multivariate linear regression were used.
Results.
We identified three pubertal progression categories using cubic polynomial function of age (“slower” (34%), “moderate” (48%), and “faster” (18%)). We used data for subjects assigned to the “slower” group (S, n=84) and combined “moderate” and “faster” into F group, n=133. We observed lower birth weight (BW) in S group compared to F group, median (25-75 perc) 3.3 (2.96-3.5) kg vs 3.5 (3.2-3.78) kg, p=3.7*10-5. In multivariate adjusted models for BW, slower pubertal trajectory was associated with higher serum FSH level (b-estimate (p) -1,26 (4.95*10-7)), lower TV 6,3 (6,9*10-35) and total progressive motile sperm 43.1 (0.0009), as well as lower BMI 1.7 (0.0004) and fat-free mass index 1,17 (3,8*10-5). No associations of pubertal trajectories were found with penile length, serum T, LH, P, TSH, free T4 level and fat mass index.
Sperm DNA methylation analysis revealed 2164582 CpGs covered 10X in samples. We found 402 differentially methylated CpG (DMCs) between S and F groups, q < 0.05 and |diff|>10%, with significantly higher levels of methylation among DMCs in the S group. Using RNA seq we identified 104 miRNA, 230 piRNA, and 13 tsRNA in sperm samples. We found differentially expressed piR-32951 and 5'-half-GluTTC (p < 0.05).
Conclusions.
Using unique prospective data of RCS we found that slower pubertal trajectory is associated with elevated serum FSH level and decreased BW, TV, BMI, fat-free mass index, altered semen quality and sperm epigenetic markers in young adulthood, but not associated with other serum reproductive hormones and penile length.