Hormonal and Sex-Specific Regulation of Key Players in Fibro-Calcific Aortic Valve Disease

Male sex and aging are risk factors for fibro-calcific aortic valve disease (FCAVD), indicating an understudied influence of sex hormones. Valvular interstitial cells (VICs) from female and male donors were isolated and exposed to pro-calcifying medium (PM), and the expression of matrix gla protein (MGP), fibronectin (FN1) and bone morphogenic protein 2 (BMP2) was analyzed. The effect of sex hormones on hydroxyapatite (HA) deposition by VICs was also analyzed. Exposure to PM increased MGP gene expression in male (<i>n</i> = 5, +5.8-fold, <i>p</i> = 0.031), and female VICs (<i>n</i> = 6, +4.9-fold, <i>p</i> = 0.004). In female VICs a +3.5-fold MGP increase accompanied the transition from the fibrotic to the calcific phase (<i>p</i> = 0.022 vs. males) while in male VICs the increase was delayed to the calcific phase. Female VICs upregulated FN1 (+1.8-fold, <i>p</i> = 0.003), while male VICs upregulated BMP2 (+3.7-fold, <i>p</i> = 0.05). 5α-dihydrotestosterone increased HA deposition +6.3-fold in male and +5.2-fold in female VICs (<i>p</i> ≤ 0.001 and <i>p</i> < 0.04, respectively). It further decreased BMP2 (<i>p</i> < 0.001) in male VICs and increased MGP in female VICs (<i>p</i> = 0.087). Female VICs decreased HA deposition when exposed to progesterone (-2.4-fold, <i>p</i> = 0.037 vs. PM) and estrogen (-2.0-fold, <i>p</i> = 0.072). In summary, VICs show donor-sex-specific gene expression which is modifiable by 5α-dihydrotestosterone. This needs to be considered when designing in vitro regulatory studies.