The use of stable isotope techniques for nutritional and metabolic research in paediatrics

• Published in: Early human development Vol. 53; pp. S77 - S97
• Main Authors: Koletzko, Berthold, Demmelmair, Hans, Hartl, Wolfgang, Angelika Kindermann, Koletzko, Sibylle, Sauerwald, Thorsten, Szitanyi, Peter
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier Ireland Ltd 01.12.1998; New York,NY Elsevier; Amsterdam
• Subjects: Biological and medical sciences; Breath-test; Carbon Isotopes; Child Nutritional Physiological Phenomena; Deuterium; Fatty acid; Fatty Acids - metabolism; Female; Fundamental and applied biological sciences. Psychology; Humans; Infant; Infant, Newborn; Isotope ratio mass spectrometry; Isotopes; Lipids. Glycolipids; Metabolism; Metabolisms and neurohumoral controls; Nitrogen Isotopes; Oxygen Isotopes; Pediatrics; Pregnancy; Stable isotope; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Breath-test; Stable isotope; Fatty acid; Isotope ratio mass spectrometry; Human; Pediatrics; Breath test; Absorption; Toxicity; Lipids; Oxidation; Metabolism; Fatty acids; Child; Isotopes; Mass spectrometry
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/S0378-3782(98)00067-X

Stable isotope methods are increasingly used in paediatrics for clinical diagnosis and research due to marked improvements in analytical technologies and better availability of suitable tracers. The safety of stable isotopes is of major importance for use in children. Large amounts of deuterium well above the doses applied under clinical conditions may induce adverse effects. In contrast, heavier stable isotopes such as 13C, 15N or 18O do not induce adverse effects even at the highest enrichments obtained, and they are safe. Breath tests with measurements of 13CO 2 enrichment after oral application of a tracer can reliably evaluate helicobacter pylori infection and gastric emptying kinetics. Combined with an estimation of total CO 2 production, 13CO 2 breath tests allow estimation of the absorption and oxidation of 13C-labelled substrates, such as medium- and long-chain triglycerides, and demonstrates the beneficial effect of carnitine supplements on fat oxidation in primary carnitine deficiency. The study of metabolic processes may require the sampling of blood for isotopic analyses of metabolites of the applied tracer. Gas chromatography–isotope ratio mass spectrometry can detect tracer in individual components from small plasma samples. The high precision enabled us to utilize the small differences in natural 13C-enrichment between dietary fats to study fatty acid turnover in term infants, in whom the dietary fat source was switched to corn oil with a slightly higher 13C-content. With this approach we demonstrated active conversion of linoleic into arachidonic acid. We also applied biotechnologically produced, U- 13C labelled linoleic and α-linolenic acids to infants and detected the conversion of these essential fatty acids to their longer chain polyunsaturated derivatives, with an apparent change of conversion activity with age. Moreover, it has become possible to measure tissue protein synthesis from small biopsy samples obtained in situ without surgery, such as forceps biopsies of rectal tumors. These few examples of recent developments demonstrate the great clinical and scientific potential of stable isotope methods in future paediatric applications.