Circulating brain-derived neurotrophic factor, leptin, neuropeptide Y, and their clinical correlates in cystic fibrosis: a cross-sectional study.

INTRODUCTION

Cystic fibrosis (CF) involves chronic inflammation and decreased pulmonary function, which increase caloric demand. Yet, sufficient energy provision is hindered by reduced appetite and fat malabsorption. Brain-derived neurotrophic factor (BDNF), leptin, and neuropeptide Y (NPY) belong to energy balance-regulating factors. We aimed to assess their concentrations in CF patients in order to search for potential clinical correlates.

MATERIAL AND METHODS

This was an exploratory, cross-sectional study. Patients' weight and height scores, forced expiratory volume in 1 s (FEV%), exocrine pancreatic status (fecal elastase-1), genotypes, and other characteristics were assessed. Serum concentrations of BDNF, leptin, NPY, IL-6, and TNF-α were measured using ELISA.

RESULTS

The study enrolled 56 patients, of whom 29 (52%) were female and 17 (30%) were younger than 16 years. Median (1-3 quartile) mass -score was -0.85 (-1.56-(-0.36)); median FEV was 70.5% (45.0-89.5); 48 (86%) patients had exocrine pancreatic insufficiency and 8 (14%) diabetes. Overall, median concentrations were: BDNF: 33.91 ng/ml (26.40-40.43), leptin: 12.05 ng/ml (8.93-17.77), NPY: 2.86 ng/ml (1.75-4.42). None of these factors correlated with mass -score, FEV%, IL-6 or TNF-α. Leptin and NPY correlated negatively (ρ = -0.62, = 3 × 10); BDNF/NPY ratio was associated with leptin (ρ = 0.54, = 2 × 10), BDNF/leptin ratio correlated with NPY (ρ = 0.60, = 1 × 10). In a multivariable regression analysis NPY was weakly, but independently, associated with FEV%, and leptin with age.

CONCLUSIONS

BDNF and leptin were not associated with weight -score or FEV%. Serum NPY concentrations seemed to be lower in CF patients with reduced pulmonary function independently of malnutrition and inflammation.