What role do adrenoreceptor polymorphisms play in modifying cardiovascular responses in obstructive sleep apnoea?

OSA (obstructive sleep apnoea) is a common condition that is strongly associated with cardiovascular disease. It is remains unclear what role OSA plays in determining cardiovascular risk. The immediate physiological changes that occur during upper airway obstruction are potential contributors to cardiovascular risk in OSA. These changes include increased sympathetic activity, which is responsive to treatment of OSA with CPAP (continuous positive airway pressure). In this issue of Clinical Science, the possible role of a common polymorphism in the β₁-adrenoreceptor [R389G (Arg389Gly)] has been investigated by Börgel and co-workers. Measurements of heart rate and blood pressure in untreated OSA patients were not related to the R389G polymorphism. There were changes in heart rate and diastolic blood pressure with CPAP treatment that were related to this polymorphism. Reduction in heart rate with CPAP treatment was associated with the R389R genotype. By contrast, a reduction in diastolic blood pressure was associated with the Gly³⁸⁹ carriers. These findings are intriguing, but difficult to fully explain. Further study is needed to determine if there is an important role of the R389G polymorphism in modifying cardiovascular responses among OSA patients.