Heart, Lung and Circulation

Sleep Disordered Breathing in Children is Associated with Increased Platelet Aggregation, Systemic Inflammation and Endothelial Dysfunction

      Introduction: Sleep disordered breathing (SDB) in adults is an independent risk factor for coronary artery disease and stroke. Altered platelet reactivity, endothelial dysfunction and inflammation in adults with SDB are known to contribute to the pathogenesis of its cardiovascular complications. Sleep disordered breathing also occurs in children; however little is known about these parameters in non-obese children with SDB. Therefore, this study investigated platelet aggregation, inflammation and endothelial function in children with SDB and healthy matched controls.
      Methods: Clinical evaluation of SDB was performed on 19 children aged 5–16 years through polysomnography (n = 12 were clinically diagnosed with SDB, n = 7 were controls). Venous blood samples were collected and analysed for measurements of platelet aggregation and inflammation. Platelet aggregation was assessed by the Multiplate analyzer. Inflammation was assessed by intracellular cytokine analysis of T cell by flow cytometry. Plasma asymmetric dimethylarginine (ADMA), a marker of endothelial function, was also quantified.
      Results: Platelet aggregation was significantly increased in SDB subjects compared to controls (56.7 ± 16.8 aggregation units (AU) vs. 38.3 ± 4.0 AU, p < 0.05). There was a significant increase in inflammation measured by T-cell interferon (IFN)-gamma (SDB 52 ± 4% vs controls 25 ± 3% positive cells, P < 0.005) and tumour necrosis factor (TNF)-alpha (SDB 39 ± 4% vs controls 20 ± 2% positive cells, P < 0.005) in SDB children compared with controls. Children with SDB also exhibited higher ADMA levels (0.43 ± 0.5 vs controls 0.35 ± 0.08 μmol/l, p < 0.05).
      Conclusion: Sleep disordered breathing in children is associated with enhanced platelet aggregation, endothelial dysfunction and inflammatory responses. These parameters may contribute to an increased cardiovascular risk for children with SDB.