Inflammatory and oxidative stress markers in serum, urine and exhaled breath condensate: Relationship between asthma and obesity in children

Abstract

Background: Systemic inflammation and oxidative stress are known to exacerbate airway inflammation in asthma. Obesity contributes to this pathophysiology.

Objective: To determine the relationship between obesity, disease severity, disease control, and oxidative stress in asthma with multiple oxidative stress markers.

Methods: The study included 65 obese-asthma (OA), 25 non-obese asthma (A), and 30 healthy non-obese controls (C). Skin prick tests, lung functions, and 8-isoprostane levels in urine samples were measured. Exhaled breath condensate (EBC) was tested for 8-isoprostane, glutathione peroxidase, and malondialdehyde (MDA). Serum samples were taken for adiponectin and leptin.

Results: OA leptin levels were higher than those of the A and C groups (p < 0.001). Glutathione peroxidase levels in EBC were found to be different between groups (p = 0.016), while there was no difference in two-group comparisons. MDA levels were significant (p < 0.001) between groups, with the A group's lower levels contributing to this significance. 8-isoprostane levels were greater in the OA group than in other groups (p = 0.005). This significance came from the difference between the OA and A groups (p = 0.005). Urine 8-isoprostane levels were different between groups (p = 0.001), and the OA group had lower levels than the A group (p = 0.003). In EBC, there were positive correlations between BMI and MDA (p < 0.001, r = 0.484) and 8-isoprostane (p < 0.001, r = 0.471). Patients with uncontrolled/partially-controlled asthma had greater levels of MDA and 8-isoprostane than those with well-controlled asthma (p = 0.036 and p = 0.011).

Conclusion: Elevated levels of MDAand 8-isoprostane in EBC in obese asthma support that obesity increases oxidative stress markers. This relationship indicate that antioxidant therapies may be beneficial in OA patients. EBC is a reliable and noninvasive technique for measuring oxidative inflammation.

Keywords: 8-Isoprostane; Asthma; Exhaled breath condensate; Malondialdehyde; Obesity.