Impact of nasal continuous positive airway pressure therapy on markers of platelet activation in patients with obstructive sleep apnea.
BACKGROUND
Considerable evidence implicates CD40 signaling in the pathogenesis of atheromas. Exposure to CD40 ligand induces platelet-leukocyte conjugation, a heightened expression of inflammatory cytokines, matrix-degrading enzymes, and procoagulant factors.


OBJECTIVE
To investigate the association between plasma soluble CD40 ligand (sCD40L) and platelet-monocyte aggregates in patients with obstructive sleep apnea (OSA) and to determine whether treatment of OSA with nasal continuous positive airway pressure (nCPAP) alters this relationship.


METHODS
Twelve patients with OSA who were free of other diseases and 12 healthy controls matched for age, gender, and body mass index had blood drawn for sCD40L and platelet-monocyte aggregate measurements. A repeat assessment was obtained following 8 weeks of nCPAP therapy.


RESULTS
Subjects with OSA had significantly higher plasma sCD40L levels and exhibited elevated platelet-monocyte aggregates compared to nonapneic subjects (7.6 +/- 4.3 versus 1.7 +/- 1.1, p = 0.004; and 41.3 +/- 23.7 versus 6.7 +/- 4.9, p = 0.001, respectively). Both parameters correlated positively with the percentage of time spent with SpO(2) <90% (r = 0.69, p = 0.01 and r = 0.6, p = 0.03, respectively). After 8 weeks of nCPAP treatment, sCD40 levels declined by 47% (p = 0.003) and platelet-monocyte aggregates by 42% (p = 0.002). None of the controls showed any changes in either sCD40L or platelet- monocyte aggregates after nCPAP therapy.


CONCLUSIONS
OSA is associated with upregulation of circulating sCD40L levels and platelet-monocyte aggregation that may account for the increased incidence of cardiovascular events in this population. Treatment with nCPAP may alleviate this risk.
Akinnusi
Morohunfolu E
ME
Division of Pulmonary, Critical Care, and Sleep Medicine, Western New York Respiratory Research Center, Department of Medicine, State University of New York at Buffalo School of Medicine and Biomedical Sciences, Buffalo, N.Y., USA.
Paasch
Linda L
LL
Szarpa
Kristie R
KR
Wallace
Paul K
PK
El Solh
Ali A
AA
D000328:Adult; D000368:Aged; D023201:CD40 Ligand / Q000097:blood*; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000503:physiopathology / Q000628:therapy*
D023201:CD40 Ligand