Regular exercise over the long term improves lung function in people with cystic fibrosis (CF) by lowering levels of a pro-inflammatory hormone called adiponectin, a new study suggests.
Measuring the levels of adiponectin and another hormone known as leptin could also be useful in monitoring CF progression, the investigators added.
Their research, “Adiponectin Expression Is Modulated by Long-Term Physical Activity in Adult Patients Affected by Cystic Fibrosis,” was published in the journal Mediators of Inflammation.
Physical activity is known to have positive effects on insulin sensitivity and blood sugar levels in diabetics and other people, including those with lung diseases.
CF patients often have disease-related complications beyond the lungs, such as limited muscle endurance. While evidence shows that respiratory muscle training, physiotherapy, and moderate physical activity improve lung health in CF, researchers do not fully understand the molecular mechanisms involved.
A team in Italy focused on the role of two hormones — adiponectin and leptin — and how their levels correlate with exercise in CF patients.
Adiponectin levels are higher than usual in people with chronic obstructive pulmonary disease and in other non-obesity-related inflammatory disorders. Mice lacking adiponectin are known to develop difficulties in lung function and systemic inflammation.
Leptin, a hormone that regulates appetite and body weight, is also involved in inflammatory diseases. Previous studies suggest that lung inflammation is associated with increased leptin release, which in turn correlates with disease worsening.
This study looked at 116 adults with CF (mean age, 30.9) diagnosed at a center in southern Italy. Among them, 58 reported engaging in physical exercise regularly over the last three years, while the other 58 were sedentary. As controls, researchers included 98 healthy volunteers (mean age, 31.1).
Physical exercise was selected and monitored by a specialized team formed by a CF physician specialist, a nutritionist, and a physiotherapist to address a concern with this activity’s impact on hydration and salt loss.
At the study’s start, CF patients compared to controls had significantly lower body mass index (22.4 vs 23.4 kg/m2), markedly lower blood (serum) cholesterol levels (140.9 vs 190.2 mg/dL), but higher glucose (sugar) levels (90.8 vs 83.2 mg/dL).
Serum levels of adiponectin were also higher in CF patients than in controls — 13.2 vs 10.2 mg/dL — while leptin levels were lower in the CF group (9.2 mg/dL in CF group, 12 mg/dL in volunteers).
Comparisons within the CF group found that serum concentrations of adiponectin were significantly lower in physically active patients than in sedentary ones, or 12.8 vs. 13.7 μg/mL. Leptin concentrations were opposite, with sedentary patients showing reduced levels compared to active patients, 7.7 vs. 10.8 ng/mL.
Researchers also observed that the levels of C-reactive protein (CRP), a marker of inflammation, were significantly lower in active than sedentary patients.
Further analysis showed that, in the active group only, lower adiponectin levels correlated with a lesser annual decrease in percent-predicted forced expiratory volume in one second (FEV1), a measure of lung function, supporting that lower adiponectin levels associate with better lung health. (FEV1 measures how much air can be exhaled in one second after a deep inhaled breath.
Lower adiponectin levels also correlated with higher amounts of lipid biomarkers (such as total cholesterol) in both active and sedentary patients, and with serum triglyceride levels in the active group only.
“Our results indicate that in CF patients, long-term physical exercise ameliorates the pulmonary phenotype, and improves the metabolic profile and systemic inflammation as shown by serum CRP reduction, adiponectin decrease, and leptin increase,” the researchers wrote.
These findings also suggest that adiponectin and leptin could be useful for monitoring disease progression, they added.