title: Role of (drug) transporters in imaging in health and disease.
abstract: This report is the summary of presentations at the symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics, April 26-30, at Experimental Biology 2014 in San Diego, CA. The presentations focused on the role of transporters in imaging in health and disease and on assessing transporter function in vivo. Imaging is an important diagnostic tool in clinics and is a novel tool for in vivo visualization of transporter function. Many imaging substrates and endogenous markers for organ function are organic anions. In this symposium, the bile salt transporter sodium taurocholate cotransporting polypeptide and the liver organic anion transporting polypeptides (OATPs) as well as the renal organic anion transporters (OATs) were addressed in detail; e.g., OATPs mediate transport of contrast agents used for magnetic resonance imaging of the liver or transport agents used for hepatobiliary scintigraphy, and OATs transport substances used in renography. In addition, the symposium also focused on the multidrug-resistance transporter 1 (MDR1 or P-gp), which is the most important gatekeeper in epithelial or endothelial barriers for preventing entry of potentially harmful substances into organs. Novel substrates suitable for positron emission tomography (PET) allow the study of such transporters at the blood-brain barrier or while they are mediating uptake of drugs into hepatocytes, and, importantly, PET tracers also now allow renography. Finally, quantitative data on transporter expression in human organs allow the development of improved physiologically based pharmacokinetic (PBPK) models for drug disposition. Hence, the combined efforts using novel substrates for in vivo visualization of transporters and quantification of transporters will lead to a deeper understanding of transporter function in disease and allow development of novel PBPK models for disease states.
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Hospital, Zurich, Switzerland (B.S.); Department of Pharmaceutics, University of Washington, Seattle, Washington (J.D.U., B.P.); Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria and Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria (O.L.); and the Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (H.G.) bruno.stieger@uzh.ch.
authors.forename: Bruno
authors.initials: B
authors.lastname: Stieger
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Hospital, Zurich, Switzerland (B.S.); Department of Pharmaceutics, University of Washington, Seattle, Washington (J.D.U., B.P.); Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria and Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria (O.L.); and the Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (H.G.).
authors.forename: Jashvant D
authors.initials: JD
authors.lastname: Unadkat
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Hospital, Zurich, Switzerland (B.S.); Department of Pharmaceutics, University of Washington, Seattle, Washington (J.D.U., B.P.); Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria and Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria (O.L.); and the Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (H.G.).
authors.forename: Bhagwat
authors.initials: B
authors.lastname: Prasad
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Hospital, Zurich, Switzerland (B.S.); Department of Pharmaceutics, University of Washington, Seattle, Washington (J.D.U., B.P.); Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria and Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria (O.L.); and the Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (H.G.).
authors.forename: Oliver
authors.initials: O
authors.lastname: Langer
authors.affiliation: Department of Clinical Pharmacology and Toxicology, University Hospital, Zurich, Switzerland (B.S.); Department of Pharmaceutics, University of Washington, Seattle, Washington (J.D.U., B.P.); Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria and Health and Environment Department, AIT Austrian Institute of Technology GmbH, Seibersdorf, Austria (O.L.); and the Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (H.G.).
authors.forename: Hariprasad
authors.initials: H
authors.lastname: Gali
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000502:physiology*; D001812:Blood-Brain Barrier / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods
chemical_list: D026901:Membrane Transport Proteins