Plasma lipidomic analysis to investigate putative biomarkers of P-glycoprotein activity in healthy volunteers.

P-glycoprotein (P-gp) is an efflux transporter involved in the bioavailability of many drugs currently on the market. P-gp is responsible for several drug-drug interactions encountered in clinical practice leading to iatrogenic hospital admissions, especially in polypharmacy situations. ABCB1 genotyping only reflects an indirect estimate of P-gp activity. Therefore, it would be useful to identify endogenous biomarkers to determine the P-gp phenotype to predict in vivo activity prior to the initiation of treatment and to assess the effects of drugs on P-gp activity. The objective of this study was to assess changes in plasma lipidome composition among healthy volunteers selected on the basis of their ABCB1 genotype and who received clarithromycin, a known inhibitor of P-gp. Untargeted lipidomic analysis based on liquid chromatography-tandem mass spectrometry was performed before and after clarithromycin administration. Our results revealed changes in plasma levels of some ceramides (Cers) {Cer(d18:1/22:0), Cer(d18:1/22:1), and Cer(d18:1/20:0) by ~38% (p < 0.0001), 13% (p < 0.0001), and 13% (p < 0.0001), respectively} and phosphatidylcholines (PCs) {PC(17:0/14:1), PC(16:0/18:3), and PC(14:0/18:3) by ~24% (p < 0.001), 10% (p < 0.001), and 23.6% (p < 0.001)} associated with both ABCB1 genotype and clarithromycin intake. Through the examination of plasma lipids, our results highlight the relevance of untargeted lipidomics for studying in vivo P-gp activity and, more generally, to safely phenotyping transporters.

[Improving practice in breast pathology: 34-months experience of the regional SENOPATH network and webinars as a tool for diagnosis of difficult lesions of the breast]. / Amélioration des pratiques en pathologie mammaire : bilan à 34 mois du groupe régional de relecture SENOPATH et télépathologie pour les lésions de diagnostic difficile.

Pathologists commonly face breast lesions that are difficult to diagnose. To reduce second opinion delay, erase geographical barrier and provide continuing education, we aimed to develop a telepathology-based regional network of pathologists. With the support of ONCOMIP network, we founded a peer-group named SENOPATH, composed of experienced breast pathologists practising in private laboratories, university hospitals or comprehensive cancer center in the region of Midi-Pyrénées in France. Submitted cases are digitalized at the University Hospital, stored in a shared space with a possible access via Internet prior to the SENOPATH sessions. The group meets monthly, via a synchronized webinar and multihead microscope session. A consensual diagnosis and final pathology report is issued for each case, and sent to the referring clinician via the patient medical file securely hosted by ONCOMIP. Between 2012 and 2014, 142 cases were reviewed, for either diagnostic 'routine' difficulty or rare histological type. The SENOPATH group, also regularly called by oncologists to solve difficult cases, has considerably improved the pathologist network in Southern France. Supported by the webinar tool, its educational impact is prominent, with a considerable progress in the region with regards to standardization of pathology processes, literature review and knowledge sharing.