Persistence of cardiac malprogramming in late gestational fetal sheep by early to midgestational testosterone excess

Excess testosterone (T) exposure from early to midgestation (days 30-90) leads to sexually dimorphic adverse cardiac left ventricular (LV) programming at fetal day 90 (term: 147 days). Whether this sexually dimorphic impact is a direct effect of T or reprogramming that persists beyond early fetal life is unknown. We hypothesized that adverse sex-specific cardiac outcomes seen in early fetal life will persist in late gestational fetuses. Pregnant ewes received 100 mg T propionate intramuscularly twice weekly from gestational days (GD) 30-90 (term: GD 147). At GD 120 ± 5, impact of T treatment on left and right ventricle (LV and RV) weight and molecular markers were investigated in female control (FC), female T-treated (FT), male control (MC), male T-treated (MT) fetuses. Data were analyzed by two-way ANOVA and Cohen's effect size (d) analysis. Morphometrically, in the LV, T excess significantly increased percent ki67-positive cells, cyclin D1 gene expression, and LV collagen and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining in both sexes. Moreover, T excess impacted cardiomyocyte nucleation in a sexually dimorphic manner in the LV. Similar changes were not seen in the RV. At a molecular level, T excess significantly downregulated pAKT/pan AKT and GLUT 4 protein selectively in LV, suggestive of insulin resistance. These findings indicate 1) persistence of the adverse organizational impact of prenatal T excess on the LV with evidence for cardiac insulin resistance in both sexes and 2) differential impact of prenatal T excess on LV vs. RV in late gestational fetuses.NEW & NOTEWORTHY Using a sheep model of human translational relevance, this study provides evidence for adverse effects of early to midgestational testosterone exposure on fetal hearts persisting beyond the time of exposure to androgen excess. Moreover, the effects are more pronounced in the left ventricle compared with the right ventricle in late gestational fetuses.