CFTR function in respiratory epithelial cell cultures: step to individualize treatments in cystic fibrosis?

Abstract

<b>Background:</b> Cystic fibrosis (CF) is caused by CFTR-dysfunction. We present an innovative method to measure CFTR-function in respiratory epithelial cells (REC). <b>Methods:</b> We derived REC from nasal brushings in CF patients and controls and processed them to air liquid interface (ALI) cultures. We measured transepithelial conductance with an ussing chamber. Change in conductance (ΔcAMP mS) is reported after applying cAMP and after introducing wtCFTR-mRNA to the cell layer with chitosan-based nanocapsules as a vector. <b>Results:</b> We performed 43 measurements in 9 patients with CF and 32 measurements in 8 controls. Median change in ΔcAMP was 0.78 (min: 0.41; max: 1.34) mS in controls and 0.03 (0.75; 0.29) in CF patients (p&lt;0.000). We propose a threshold of 0.3 ΔcAMP mS to discriminate CF from non-CF epithelia. We transfected REC of 6 CF patients (n=26 measurements) with wtCFTR-mRNA. Median ΔcAMP was 0.81 (0.10; 1.77) in controls and 0.03 (-0.93; 0.29) in CF at baseline and 0.83 (0.37; 1.88) 0.43 (-0.02; 1.19), 0.18 (0.07; 0.21) at 24, 48 and 72 hours (h) after transfection with wtCFTR-mRNA in CF patients. Median ΔcAMP at baseline and after 24h and 48h but not after 72h were statistically significantly different. <b>Conclusions:</b> Conductance measurements with the ussing chamber is feasible in ALI cultures from CF patients and assesses CFTR function. Measurements discriminate CF from non-CF patients and show a treatment response after transfection with wtCFTR. The method may be an additional diagnostic tool to measure CFTR function, is a promising method for testing substances for CFTR restoration and may guide future individualized CFTR-modulator therapy in CF.