Differences in gene expression related to the outcomes of obesity treatment, peak oxygen uptake, and fatty acid metabolism measured in a cardiopulmonary exercise test.

INTRODUCTION The obesity pandemic requires development of methods that could be used on a large scale, such as the cardiopulmonary exercise test (CPET). Gene expression may explain CPET results on the molecular level. OBJECTIVES The aim of this study was to compare gene expression in obesity, depending on CPET results. PATIENTS AND METHODS The study group consisted of 9 obese patients and 7 controls. The treatment encompassed diet, rehabilitation, and behavioral therapy. Diet was based on the body composition analyzed by bioelectrical impedance, resting metabolic rate, and subjective patient preferences. The rehabilitation depended on the CPET results: maximal oxygen uptake and fatty acid metabolism. Behavioral intervention focused on the diagnosis of health problems leading to obesity, lifestyle modification, training in self­assessment, and development of healthy habits. The intensive treatment lasted for 12 weeks and consisted of consultations with a physician, dietitian, and medical rehabilitation specialist. RNA was isolated from the whole blood. A total of 47 323 transcripts were analyzed, of which 32 379 entities were confirmed to have high quality of RNA. RESULTS We observed differences in gene expression related to the CPET results indicating abnormalities in fat oxidation and maximal oxygen uptake. The genes with major differences in expression were: CLEC12A, HLA­DRB1, HLA­DRB4, HLA­A29.1, IFIT1, and LOC100133662. CONCLUSIONS The differences in gene expression may account for the outcomes of treatment related to inflammation caused by obesity, which affects the muscles, fat tissue, and fatty acid metabolism.