Purpose: The relationship between obstructive sleep apnea (OSA) and atherosclerosis-related inflammation has been poorly investigated, particularly focusing on functional responses of immune cells playing a key role in atherogenesis and in comparison with control groups with similar cardiovascular risk factors which are known to be themselves associated with inflammation. We sought to determine cellular tumor necrosis factor-alpha (TNF-α) production from peripheral blood mononuclear cells (PBMCs) and interleukin (IL)-8 release from neutrophils (PMNs) in patients studied for suspected OSA.
Methods: Thirty-six consecutive patients who underwent a nocturnal complete cardiorespiratory evaluation for suspected OSA were initially evaluated. Serum, PBMCs, and PMNs were isolated (at baseline and after 12 weeks) from patients with apnea-ipopnea index (AHI) >20 (OSA group, n = 16) and from control patients with AHI <5 (nonOSA group, n = 11). All patients continued the same pharmacological therapy for 12 weeks; the OSA group was additionally treated with nocturnal continuous positive-airway-pressure ventilation (cPAP).
Results: The two groups had similar clinical characteristics (prevalence of hypertension, dyslipidemia, diabetes, and cardio-metabolic therapies) except for obesity. Resting and stimulated TNF-α production from PBMCs and IL-8 release from PMNs were similar in the two groups. Serum cytokines resulted within the normal range. In the OSA group, cPAP was not associated with changes in cellular responses.
Conclusions: In patients showing similar prevalence of major cardiovascular risk factors and cardio-metabolic therapies, differing for the presence or absence of OSA, cytokine productions from PBMC and PMN were similar and were not modified during cPAP therapy. Studies designed to investigate OSA-associated inflammation should carefully match the control group subjects.