Polycystic ovary syndrome (PCOS) is the most common endocrinopathy among reproductive-aged women, affecting ~10% of premenopausal women. Women with PCOS present with myriad cardiovascular risk factors including greater muscle sympathetic nerve activity (MSNA), however this has yet to be assessed during periods of reactivity. Interestingly, there is limited evidence to suggest that testosterone (i.e. free testosterone), which is elevated in ~75% of women with PCOS, may play a role in mediating greater MSNA in PCOS. Therefore, the purpose of this study was to test the hypotheses that (a) women with PCOS would exhibit greater MSNA reactivity in response to acute stress relative to control (CTRL) women, and (b) MSNA reactivity to stress would be positively correlated with elevated testosterone levels. We tested 4 lean women with PCOS and 4 CTRL women (age: 20±1 vs. 23±3 yrs, P=0.12; BMI: 25±3 vs. 24±2 kg/m2, P=0.41). Heart rate (3-lead ECG), beat-by-beat blood pressure (Finapres) and MSNA (microneurography at the peroneal nerve) were measured during 3-min of quiet rest and during a maximal voluntary end-expiratory breath hold. Analyses were performed comparing baseline to the latter half of the apnea, in which sympathetic reactivity was the greatest. Baseline mean arterial pressure (MAP) was similar between PCOS and CTRL (87±7 vs. 86±5 mmHg, P=0.97), as were MSNA burst frequency (BF) and MSNA burst incidence (BI) (BF: 7±5 vs. 10±7 bursts/min, P=0.51; BI: 10±8 vs. 16±10 bursts/100hb, P=0.50). Apnea induced increases in MAP and MSNA in both groups (main effects of condition: MAP, Plt;0.05; BF, Plt;0.01; BI, Plt;0.01). However, MSNA during apnea was higher in women with PCOS compared to CTRL women (BF: 55±7 vs. 35±12 bursts/min, Plt;0.05; BI: 81±18 vs. 50±13 bursts/100hb, Plt;0.05). When all participants were pooled together, a trend towards a positive modest correlation between serum free testosterone concentrations and MSNA BI during apnea was observed (R2=0.33; P=0.18). These preliminary data provide some evidence that elevated testosterone levels observed in women with PCOS may contribute to greater sympathetic reactivity, although this requires further study. Importantly, despite greater MSNA responses to apnea, women with PCOS demonstrated similar BP responses to the CTRL group. These findings suggest that these young lean women with PCOS may benefit from an offsetting of high MSNA, which may be mediated by blunted neurovascular transduction.
Support or Funding Information
This project is funded by the Natural Sciences and Engineering Research Council Discovery Grant.
This project is funded by the Natural Sciences and Engineering Research Council Discovery Grant.lt;ins cite="mailto:Celine%20Chen" datetime="2021-11-30T14:07"gt;lt;/insgt;
