Testing human monocytes as a new tool for clinical and preclinical research in CF.

Functional CFTR is currently directly evaluated in humans using two procedures: rectal biopsies followed by Ussing chamber analysis and nasal potential difference analysis (NPD). Even if only the first require a surgical procedure, nevertheless both can be considered invasive as they require either the removal of tissue (the former) or the use of small electrode on the nasal mucosa (the latter). For this and other practical reasons, for both rectal biopsies and (although to a lesser extent) NPD analysis, the possibility to be repeated multiple times on the same subject, in particular younger subjects, is not practically feasible. Our published data confirm the possibility to apply a well described single-cell fluorescence imaging approach to human monocytes, thus making possible to evaluate CFTR functionality in blood cells. This approach permit to work on with a minimally invasive methodology (a venous blood drawn of 5-10 cc) facilitating the evaluation of CFTR activity in all the cases of relevance in research and clinic, possibly including the evaluation of drugs affecting CFTR function. Our project is the extension of FFC#05/2009 and aims to the evaluation of the monocyte assay on a population of subjects affected by lung disease other than CF and to evaluate ex vivo, on monocyte of CF subjects for the first time, the response to drugs targeting the basic defect of CF, including VX809 and PTC124. It is important to underline the fact that we will have the unique opportunity to evaluate the response to a novel drug, PTC 124, now undergoing a multicentric phase 3 clinical trial in the CF Center in Verona on 15 subjects. Importantly, we have already obtained clearance from the local ethical commettee and from PTC Therapeutics that is organizing this multicenter clinical trial that has recognized the potential of this test for improving the efficacy of future clinical trials. These monocytes will be analyzed also with patch clamp, a highly complex technique that is capable to record the current from single channels present on the cell membrane and represent the gold standard in ion channel research. Eventually, a faster access of the patients to new drugs might be envisaged as this application, once properly validated, might expedite the organization and evaluation of clinical trials based on the use of CFTR correctors.