Detection of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Activity in Rectal Tissues From Human Subjects

CF research has advanced to the point where small molecule agents have been developed to overcome the underlying genetic defects caused by CFTR mutations. There is a critical need to develop new sensitive biomarkers of CFTR function and biochemistry that can be used in early phase clinical trials to demonstrate biologic effects of investigative agents in vivo. Intestinal Current Measurement (ICM) from rectal biopsy samples is an assay that has been proven to be sensitive and specific for CFTR function. This method and site of investigation is particularly attractive, since CFTR is expressed at high levels in the rectum, it is not altered by disease manifestations, and the tissue can be studied ex vivo, providing more flexibility in the nature of the techniques to detect and quantify CFTR activity. This study will aid in the development of new biomarkers in human rectal tissue for use in CF clinical trials. Testing compounds that are designed to restore function to disease-causing CFTR genes and proteins will provide an opportunity to improve and standardize techniques in the acquisition and measurement of CFTR activity in rectal biopsy specimens.