Respiratory burden in obese and young asthmatics: a study of diaphragmatic kinetics

Abstract

Objective: The aim of this study was to assess the diaphragm kinetics, respiratory function, and serum dosage of leptin and inflammatory cytokines (IL-6 and TNF-a) in three clinical groups: obese, asthmatic, and healthy. Methods: This is a clinical exploratory study performed on 73 youths (12-24 years of age, 42.5% male) allocated into three groups: obesity (OG, n=33), body mass index (BMIz-score) = +2, asthmatic (AG, n=26) controlled mild asthmatics, classified by GINA, and Healthy Control Group (CG, n=14). The participants were subjected to diaphragmatic ultrasound, spirometry, maximal respiratory pressure, serum leptin levels, and IL-6 and TNF-a whole blood cell culture levels. Results: Diaphragm thickness was higher in OG in comparison to AG and CG (2.0±0.4 vs 1.7±0.5 and 1.6±0.2, both with p<0.05). Maximal voluntary ventilation (MVV) was significantly lower in OG and AG in relation to the CG (82.8±21.4 and 72.5±21.2 vs 102.8±27.3, both with p<0.05). OG has the highest leptin rate among the groups (with the other two groups had p<0.05). All groups had similar TNF-a and IL-6 levels. Conclusion: The muscular hypertrophy found in the diaphragm of the obese individuals can be justified by the increase in respiratory work imposed by the chronic condition of the disease. Such increase in thickness did not occur in controlled mild asthmatics. The IL-6 and TNF-a markers detected no evidence of muscle inflammation, even though leptin was expected to be altered in obese individuals. Both obese and asthmatic patients had lower pulmonary resistance than the healthy ones.

ER stress aggravates diaphragm weakness through activating PERK/JNK signaling in obesity hypoventilation syndrome

“…Compared with well‐studied peripheral muscle tissues, how obesity affects diaphragmatic function remains largely unknown. A previous report showed the muscular hypertrophy of the diaphragm in young people with obesity [37]. Animal models with obesity also displayed morphological and kinematic changes of the diaphragm, such as increased thickening fraction, excursion, and dome height [38], suggesting the adaptation of the diaphragm to the increased burden of metabolic stresses.…”