title: Dynamic carbon 13 breath tests for the study of liver function and gastric emptying.
abstract: In gastroenterological practice, breath tests (BTs) are diagnostic tools used for indirect, non-invasive assessment of several pathophysiological metabolic processes, by monitoring the appearance in breath of a metabolite of a specific substrate. Labelled substrates originally employed radioactive carbon 14 ((14)C) and, more recently, the stable carbon 13 isotope ((13)C) has been introduced to label specific substrates. The ingested (13)C-substrate is metabolized, and exhaled (13)CO2 is measured by mass spectrometry or infrared spectroscopy. Some (13)C-BTs evaluate specific (microsomal, cytosolic, and mitochondrial) hepatic metabolic pathways and can be employed in liver diseases (i.e. simple liver steatosis, non-alcoholic steato-hepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug and alcohol effects). Another field of clinical application for (13)C-BTs is the assessment of gastric emptying kinetics in response to liquids ((13)C-acetate) or solids ((13)C-octanoic acid in egg yolk or in a pre-packed muffin or the (13)C-Spirulina platensis given with a meal or a biscuit). Studies have shown that (13)C-BTs, used for gastric emptying studies, yield results that are comparable to scintigraphy and can be useful in detecting either delayed- (gastroparesis) or accelerated gastric emptying or changes of gastric kinetics due to pharmacological effects. Thus, (13)C-BTs represent an indirect, cost-effective and easy method of evaluating dynamic liver function and gastric kinetics in health and disease, and several other potential applications are being studied.
authors.affiliation: Department of Biomedical Sciences and Human Oncology, Clinica Medica 'A. Murri', University of Bari Medical School, Bari, Italy and Italian College of General Practitioners, Florence and Bari, Italy.
authors.forename: Leonilde
authors.initials: L
authors.lastname: Bonfrate
authors.affiliation: Department of Biomedical Sciences and Human Oncology, Clinica Medica 'A. Murri', University of Bari Medical School, Bari, Italy and Italian College of General Practitioners, Florence and Bari, Italy.
authors.forename: Ignazio
authors.initials: I
authors.lastname: Grattagliano
authors.affiliation: Department of Biomedical Sciences and Human Oncology, Clinica Medica 'A. Murri', University of Bari Medical School, Bari, Italy and Italian College of General Practitioners, Florence and Bari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Palasciano
authors.affiliation: Department of Biomedical Sciences and Human Oncology, Clinica Medica 'A. Murri', University of Bari Medical School, Bari, Italy and Italian College of General Practitioners, Florence and Bari, Italy piero.portincasa@uniba.it.
authors.forename: Piero
authors.initials: P
authors.lastname: Portincasa
keywords: breath tests; gastric motility; hepatic metabolism; scintigraphy; stable isotope