T regulatory lymphocytes and endothelial function in pediatric obstructive sleep apnea

Area of Science:

• Immunology
• Pediatrics
• Cardiology

Background:

• Obstructive sleep apnea (OSA) is a chronic inflammatory condition impacting cardiovascular and metabolic health.
• Pediatric OSA is associated with reduced T-regulatory lymphocytes (Tregs), which are crucial for immune regulation.
• Tregs influence endothelial activation and insulin resistance, prompting investigation into their role in pediatric OSA complications.

Purpose of the Study:

• To investigate the association between T-regulatory lymphocytes (Tregs) and endothelial and metabolic dysfunction in children with obstructive sleep apnea (OSA).
• To explore the relationship between Treg percentage, Treg suppressive function, and markers of endothelial function and insulin resistance in pediatric OSA.

Main Methods:

• Fifty children (ages 4.8-12 years) with OSA underwent polysomnography and assessment of insulin resistance via HOMA.
• Flow cytometry was used to determine the percentage of circulating Tregs.
• Endothelial function was assessed by measuring the time to peak occlusive hyperemia (Tmax); in vitro Treg suppression tests were performed in a subgroup.

Main Results:

• Circulating Tregs showed no significant association with BMI z-score or HOMA (insulin resistance).
• A significant inverse correlation was found between Treg percentage and Tmax, indicating impaired endothelial function (p<0.0001, r=-0.56).
• Treg suppressive function negatively correlated with the sleep pressure score (SPS), a marker of sleep fragmentation (p=0.02, r=-0.51).

Conclusions:

• Endothelial dysfunction in pediatric OSA is significantly associated with circulating Tregs and their suppressive capacity.
• The findings suggest that Treg alterations, potentially linked to sleep fragmentation, may contribute to cardiovascular morbidity in children with OSA.
• Insulin resistance was not found to be associated with Treg levels in this pediatric OSA cohort.