High sputum total adiponectin is associated with low odds for asthma

Abstract

Objective: Adipose tissue produces adiponectin, an anti-inflammatory protein. High systemic total adiponectin is associated with a low risk for incident asthma but the association with lung adiponectin is not known. Our objective was to evaluate the association between sputum total adiponectin and asthma. Methods: This case-control study included 44 cases with objectively-confirmed asthma and an equal number of body mass index (BMI) and sex-matched controls. Serum and sputum adiponectin were estimated by ELISA and Western Blot technique, respectively. While Fisher’s exact test, t-test and Spearman’s correlations were used for univariate analyses, Spearman and regression analyses were performed for multivariable analyses. Results: While high-molecular-weight adiponectin was the dominant isoform in serum, medium-molecular-weight isoform was dominant in sputum. Sputum total adiponectin was not correlated with serum adiponectin or BMI. Sputum total adiponectin was lower among asthmatics than controls (p = 0.03), although individual sputum isoforms were not similarly associated. High sputum total adiponectin was associated with lower odds for asthma (OR 0.33, 95% C.I. 0.12, 0.91), even after adjustment for systemic adiposity measures including serum adiponectin. Conclusions: High sputum total adiponectin predicted lower odds for asthma, even after adjustment for serum adiponectin. Although not studied, it is possible that pharmacological modulation of sputum adiponectin may suggest new ways to prevent and/or treat asthma.

• Adiponectin
• adiposity
• airway inflammation
• asthma
• obesity
• oxidant stress

Acknowledgements

Akshay Sood, MD, MPH takes responsibility for (is the guarantor of) the content of the manuscript, including the data and analysis. AS, JS, GH, MH, YA, AC, RS, PM, MC, MH, CQ, MB and MS made substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; drafted the submitted article or revised it critically for important intellectual content; and has provided final approval of the version to be published. We would like to thank Umar Cheema, University of New Mexico School of Medicine, Albuquerque, NM, USA for his help with data collection.