The effect of growth hormone on sleep-related cardio-respiratory control in Prader-Willi syndrome

Abstract

Aim: To evaluate the effects of growth hormone (GH) treatment on control of breathing, heart rate and blood pressure during sleep in Prader-Willi Syndrome (PWS).

Study design: In a prospective clinical case series study, sixteen consecutive PWS patients (median age 16 months at enrolment) were followed-up 6 months (2-32 months) after commencing GH treatment. We compared heart rate (HR), Pulse Transit Time (PTT; an index of blood pressure, BP) and ventilatory responses to standard chemostimuli (4% CO(2) and 100% O(2)) during quiet sleep prior to and after commencing GH treatment.

Results: Growth hormone treatment increased arterial oxygenation during sleep but did not significantly improve breathing stability (apnoea-hypopnoea index remained unchanged). GH treatment did not alter ventilatory, HR and PTT chemoreceptor-mediated responsiveness (p = 0.23-0.97) but did significantly improve the coupling between and HR and PTT, indicating that HR and BP rose (or fell) in parallel after but not before GH therapy (p = 0.01).

Conclusion: Growth hormone treatment improves arterial oxygenation and cardiovascular function during sleep; these changes are not owing to improved (stronger) chemoreflex-mediated autonomic drive.