Objectives: Central and peripheral chemosensitivity i.e. ventilatory response to CO2 and O2 are thought to be decisive for ventilatory control instability in obstructive sleep apnoea (OSA). Obesity is associated with chronic low level inflammation. Whether body mass related inflammatory and anti-inflammatory factors influencing peripheral and central chemosensitivity differentially is unclear.
Methods: Ventilatory response to hypercapnic-hyperoxic and hypercapnic-hypoxic gas mixtures in patients with OSA (n = 46) and healthy individuals (n = 45) was measured. C-reactive protein (CRP), leptin, adiponectin, and endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) were measured in blood samples.
Results: Mediation analysis revealed that association of chemoresponse to CO2 with apnoea hypopnea index (AHI) was fully mediated by body mass index (BMI). Regression analysis showed that CRP and leptin levels explained ˜25% and ˜15% of the variance in central CO2 response, while 2-AG explained ˜42% of the variance in peripheral response to hypoxia.
Conclusion: Inflammatory and anti-inflammatory factors could explain differential alterations in peripheral and central ventilatory chemoresponse in patients with OSA.
Keywords: C-reactive protein; Chemosensitivity; Endocannabinoids; Inflammation; Obesity; Obstructive sleep apnoea.
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