Association between serum YKL-40 level and dysglycemia in cystic fibrosis

Background: YKL-40, a chitinase-like protein, is a biomarker for type 1 and type 2 diabetes prognosis. We hypothesized that YKL-40 protein levels are elevated in CF patients with dysglycemia. Methods: Seventeen healthy control subjects and 66 CF patients were prospectively recruited and subjected to an oral glucose tolerance test. In all participants, fasting serum YKL-40 was compared between control and CF patients and between normal glucose-tolerant patients (NG-CF) and CF patients with dysglycemia (DG-CF). A Botnia clamp procedure was performed on a subset of patients for each group to determine the impact of acute increases of either glucose or insulin on YKL-40 concentration. Results: CF patients had higher serum YKL-40 values than the controls (113 [49;288] vs. 38 [30;50] ng/ml, p < 0.001). YKL-40 concentrations in CF patients were mainly increased in the DG-CF group, who had significantly higher values: 213 [93;383] vs. 67 [27;97] ng/ml in the NG-CF group, p < 0.001). No significant modulation of YKL-40 concentration was observed in serum of CF (NG or DG-CF) or non-CF patients, after acute exposure to glucose or insulin. Conclusions: Higher serum YKL-40 levels in CF patients are significantly associated with dysglycemia. The increase in YKL-40 is potentially associated with an inflammatory response resulting from chronic glucose intolerance or CF disease evolution. (C) 2014 Published by Elsevier Ltd.