Stable isotopes in obesity research

Abstract

Obesity is recognized as a major public health problem. Obesity is a multifactorial disease and is often associated with a wide range of comorbidities including hypertension, non-insulin dependent (Type II) diabetes mellitus, and cardiovascular disease, all of which contribute to morbidity and mortality. This review deals with stable isotope mass spectrometric methods and the application of stable isotopes to metabolic studies of obesity. Body composition and total energy expenditure (TEE) can be measured by mass spectrometry using stable isotope labeled water, and the metabolism of protein, lipid, and carbohydrate can be measured using appropriate labeled tracer molecules.

Colonization resistance and microbial ecophysiology: using gnotobiotic mouse models and single-cell technology to explore the intestinal jungle

“…Certainly, many approaches for in vivo stable isotope labeling and analysis of the intestinal microbiota will initially be developed in animal models (Berry et al, 2013) before they will be applied to humans. However, stable isotope tracer application to humans in vivo is not fiction but already for some applications a standard tool in biomedicine for revealing host physiology and quantification of metabolic fluxes (Kelleher, 2004;Dolnikowski et al, 2005;de Graaf & Venema, 2008). For example, whole-body turnover of SCFA in animals and humans, which depends on endogenous turnover and exogenous production by intestinal microbiota, has been determined after intravenous infusion of 13 C-labeled acetate, propionate, and/or butyrate (Pouteau et al, 2003).…”

Mass spectrometry and isotopes: A century of research and discussion

“…Two examples where problems arose will be mentioned here. For carbon, the Peedee belemnite was used, but the supply is now exhausted, and various ersatz standards are recommended in its place (for a discussion of the standards of H, C, and O see Dolnikowski et al, 2005). Lithium has caused difficulties because large amounts of it have been isotopically fractioned by removal of 6 Li for use in hydrogen bombs, and some of this depleted material has found its way into laboratory reagents and into the environment (Coplen et al, 2002).…”

“…and flavors (addition of synthetic material) see Asche et al (2003); for a multielement approach see Camin et al (2004). The use of isotopic ratio measurements to follow the fate of labeled compounds in studies of metabolism has been reviewed recently (Dolnikowski et al, 2005); applications in climate change research have been summarized by Ghosh & Brand, 2003. Isotope ratio patterns can also be used to some extent to determine the geographic region of birth and recent living of humans. Sr incorporated in tooth material preserves the pattern of the environment where a person lived during childhood, while in bones a steady exchange occurs with a rate of approximately 10% per year (slower in the skull, faster, e.g., in the pelvis).…”

Use of dual isotope tracers in biomedical research

“…Digestion of nutrients is monitored by measurement of enriched nutrients such as glucose, fatty acids, amino acids or their metabolic products in blood * 13 19 November 2014 or breath (labelled CO 2 ) after oral administration of labelled carbohydrates [6,7], triglycerides [8,9] and proteins [10]. A special application is the measurement of body composition and energy expenditure on the basic of administration of singly (deuterium) or doubly labelled (deuterium, 18 O) water, respectively [11,12].…”