Ghrelin treatment suppresses neutrophil-dominant inflammation in airways of patients with chronic respiratory infection

BackgroundPersistent neutrophil influx into the airways is a characteristic of chronic respiratory infection and contributes to the deterioration of pulmonary function. Ghrelin is a novel growth hormone (GH)-releasing peptide with potential anti-inflammatory activities. The present study investigated whether or not ghrelin can reduce neutrophil-dominant inflammation in airways of patients with chronic respiratory infection.Populations and methodsSynthesized ghrelin was administered intravenously for 3 weeks to 7 cachectic patients with chronic respiratory infection to confirm ghrelin's effects on airway inflammation and nutrition state. Neutrophils, neutrophil products and inflammatory cytokines in sputum were used as markers of airway inflammation. Changes in serum protein levels were also evaluated along with plasma catecholamine levels. Exercise tolerance was assessed by measuring 6-min walking distance before and after 3 weeks of ghrelin treatment.ResultsThree-week ghrelin administration decreased neutrophil density and inflammatory cytokine levels in sputum, reduced plasma norepinephrine level, and increased body weight, serum protein level, and 6-min walking distance.ConclusionsGhrelin administration suppressed airway inflammation by decreasing neutrophil accumulation in lungs and increased body weight. These findings may contribute to the development of supportive therapies for patients with refractory chronic respiratory infection.