Sweat: a sample with limited present applications and promising future in metabolomics

Abstract

Sweat is a biofluid with present scant use as clinical sample. This review tries to demonstrate the advantages of sweat over other biofluids such as blood or urine for routine clinical analyses and the potential when related to metabolomics. With this aim, critical discussion of sweat samplers and equipment for analysis of target compounds in this sample is made. Well established routine analyses in sweat as is that to diagnose cystic fibrosis, and the advantages and disadvantages of sweat versus urine or blood for doping control have also been discussed. Methods for analytes such as essential metals and xenometals, ethanol and electrolytes in sweat in fact constitute target metabolomics approaches or belong to any metabolomics subdiscipline such as metallomics, ionomics or xenometabolomics. The higher development of biomarkers based on genomics or proteomics as omics older than metabolomics is discussed and also the potential role of metabolomics in systems biology taking into account its emergent implementation. Normalization of the volume of sampled sweat constitutes a present unsolved shortcoming that deserves investigation. Foreseeable trends in this area are outlined.

Keywords: ANOVA; CE; CF; CFTR; Cystic fibrosis; DAD; DCD; Da; Dalton; EI; EIA; ELISA; ESI; FID; GC; GHB; Genomics; HMDB; ISE; LC; LLE; LOQ; METLIN; MRMMS; MS; Metabolomics; NMR; PCA; PIP; PLS-DA; Proteomics; R; RIA; Robert and Ross programme language; SPE; Sweat; TOF; UV; analysis of variance; capillary electrophoresis; cystic fibrosis; cystic fibrosis transmembrane conductance regulator; dermcidin; diode array detector; electron impact ionization; electrospray ionization; enzyme immunoassay; enzyme linked immunoassay; flame ionization detector; gamma hydroxybutyrate; gas chromatograph/gas chromatography; human metabolome data base; ion selective electrode; limit of quantitation; liquid chromatograph/liquid chromatography; liquid–liquid extraction; mass spectrometer/mass spectrometry; metabolite and tandem MS data base; multiple reaction monitoring mass spectrometry; nuclear magnetic resonance spectroscopy; pROC; partial least squares-discriminant analysis; partial receiver operating characteristics; principal components analysis; prolactin inducible protein; radio immunoassay; solid-phase extraction; time-of-flight; ultraviolet.