Relation of exhaled breath temperature and systemic markers of inflammation and remodelling in stable bronchial asthma

Background: Bronchial Asthma is characterized by chronic airway inflammation with airway remodeling. Exhaled breath temperature may also assess airway inflammation, since heat production, one of the cardinal features of inflammation has a potential to reflect local inflammation in asthmatics. Not many studies have addressed the relation between airway inflammation and systemic markers of inflammation and remodeling. Objective: To evaluate markers of inflammation and remodeling in blood and their relation with exhaled breath temperature (EBT) in stable asthmatics. Methods: 24 male stable asthmatics and 23 age matched healthy controls were recruited. Tidal breathing EBT was measured by X- Halo breath thermometer. Body temperature was measured by Omeron9s Gentel temp instant ear thermometer. Interleukin-6 (IL-6), vascular endothelial growth factor(VEGF), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1(TIMP-1) were quantified in serum by ELISA. Results: Serum levels of IL-6(p=0.006), VEGF(p=0.01) and MMP-9(p=0.002) were significantly raised in asthmatics as compared to aged matched healthy controls. Mean EBT in asthamatics (34.17 ± 0.61°c) was significantly higher than healthy controls(p=0.038), with statistically comparable core body temperature in both groups. EBT did not show any significant correlation with quantified serum biomarkers of inflammation and repair in asthmatics. Conclusion: EBT may be used as a non-invasive tool for assessment of airway inflammation. Markers of inflammation and remodelling were raised in blood but there was no relation between airway inflammation and the systemic cytokines in asthma.