Applications of stable, nonradioactive isotope tracers in in vivo human metabolic research

Abstract

The human body is in a constant state of turnover, that is, being synthesized, broken down and/or converted to different compounds. The dynamic nature of in vivo kinetics of human metabolism at rest and in stressed conditions such as exercise and pathophysiological conditions such as diabetes and cancer can be quantitatively assessed with stable, nonradioactive isotope tracers in conjunction with gas or liquid chromatography mass spectrometry and modeling. Although measurements of metabolite concentrations have been useful as general indicators of one's health status, critical information on in vivo kinetics of metabolites such as rates of production, appearance or disappearance of metabolites are not provided. Over the past decades, stable, nonradioactive isotope tracers have been used to provide information on dynamics of specific metabolites. Stable isotope tracers can be used in conjunction with molecular and cellular biology tools, thereby providing an in-depth dynamic assessment of metabolic changes, as well as simultaneous investigation of the molecular basis for the observed kinetic responses. In this review, we will introduce basic principles of stable isotope methodology for tracing in vivo kinetics of human or animal metabolism with examples of quantifying certain aspects of in vivo kinetics of carbohydrate, lipid and protein metabolism.

Metabolômica: Definições, Estado-Da-Arte E Aplicações Representativas

“…124 além do entendimento das alterações metabó-licas resultantes da realização de atividades físicas e seus impactos na saúde, especialmente na prevenção de doenças. 125,126 O efeito da prática de exercícios é tópico de uma série de estudos, como alterações no metabolismo e envelhecimento, [127][128][129] efeito no crescimento infantil 130 e ainda, prevenção de doenças em mulheres grávidas e seus fetos. 131,132 Bassini e Cameron introduziram, em 2014, o termo sportomics como sendo a "investigação das alterações metabólicas em indivíduos durante a prática de esportes e exercícios físicos", que visa auxiliar no entendimento do metabolismo na prática de esportes e aprimoramento da ciência do esporte, na busca de melhor performance, treinamento e recuperação.…”

Measurement of metabolic fluxes using stable isotope tracers in whole animals and human patients

“…Numerous studies have uncovered metabolic differences and differential responses to stimuli between cancer cells grown in culture and the tumor in vivo . In vivo imaging techniques have historically exploited fluorescent or radioactive substrates to visualize the uptake and consumption of substrates of interest (e.g., fluorodeoxyglucose), though these approaches do not provide information about metabolic fluxes in vivo and require special licenses to handle and dispose of radioactive compounds, leading to obvious safety concerns for study participents and investigators [8,9]. These hurdles are overcome through the use of stable isotope tracers in vivo .…”

New trends and applications in cyanation isotope chemistry

“…5 In addition to those 2 radioactive carbon isotopes, carbon-13 labeled compounds have many vital uses including structure elucidation via NMR experiments, as mass spectrometry standards, 6 as environmental and forensic markers, 7 or for identifying human metabolites in tracer studies. 8 For all these carbon isotopes ( 11 C, 13 C, 14 C), specific methods, with different synthetic optimization requirements, are of interest to isotope chemists.…”