Metabolomics in critical care medicine: a new approach to biomarker discovery Abstract Purpose: To present an overview and comparison of the main metabolomics techniques ( 1 H NMR, GC-MS, and LC-MS) and their current and potential use in critical care medicine.Source: This is a focused review, not a systematic review, using the PubMed database as the predominant source of references to compare metabolomics techniques.Principal Findings: 1 H NMR, GC-MS, and LC-MS are complementary techniques that can be used on a variety of biofluids for metabolomics analysis of patients in the Intensive Care Unit (ICU). These techniques have been successfully used for diagnosis and prognosis in the ICU and other clinical settings; for example, in patients with septic shock and community-acquired pneumonia.
Conclusion:Metabolomics is a powerful tool that has strong potential to impact diagnosis and prognosis and to examine responses to treatment in critical care medicine through diagnostic and prognostic biomarker and biopattern identification.
REVIEW ARTICLE © 2014 CIMClin Invest Med • Vol 37, no 6, December 2014 E363 Metabolomics refers to the systems level analysis of the metabolism and metabolites in response to physiological stimuli, such as disease or drug administration [1]. The application of clinical metabolomics to the complex illnesses of critical care medicine is relatively new [1,2]. Metabolomics, which is most commonly based on nuclear magnetic resonance (NMR) spectroscopy, gas chromatography-mass spectrometry (GC-MS) and/or liquid chromatography-mass spectrometry (LC-MS) platforms, provides an accurate reflection of the metabolic processes and pathways at play within the human body at a particular moment in time [1].
History of metabolomicsWhile the terms metabolomics and metabonomics are now used interchangeably, their original definitions focused on the level of analysis and the type of analytical technology used. This paper uses the term metabolomics as the terms are often treated as interchangeable and it is more commonly used in the literature than the term metabonomics [1,2]. Nicholson, who first defined metabonomics in 1999, described it as a systemsbased strategy to "measure the global, dynamic metabolic response of living systems to biological stimuli or genetic manipulation" [2]. Conversely, metabolomics was defined as the identification, analysis, and quantification of each metabolite within a biosample [3]. Metabolomics and metabonomics can also be defined by their method of analysis: metabolomics was originally described as a GC-MS-based approach in the study of plant metabolomes [3] and metabonomics was originally defined as NMR-based study of mammalian systems [2]. Although metabolomics and metabonomics were not defined until the late 1990s, biofluid analysis by GC-MS was first reported in the 1960s and 1970s [4]. The basis of today's metabolomics field started in the early 1980s, when NMR technology became adequately sensitive for biofluid metabolite identification. Combined with the use of statisti...