Determination of stress-induced changes in plasma molecular species by two-dimensional correlation Fourier transform infrared spectrometry

For determining exercise-induced changes in plasma molecular species, we investigated the feasibility of using twodimensional correlation spectra (2D-COS) on 21 series of plasma samples obtained from progressive exercise tests. Intensities of 2D synchronous and asynchronous correlation peaks were compared to concentration evolutions of glucose, lactate, triglycerides (TG), glycerol, fatty acyl moieties, amino acids, proteins, and albumin [determined from plasma Fourier transform infrared (FTIR) spectra] and to performance and training levels of athletes. Synchronous 2D-COS allowed us to determine the linear relationship between protein and fatty acid concentration evolutions as exercise intensity increased ((nu)1 - (nu)2; 2959 vs 1656 and 1543 cm^-1). Asynchronous 2D-COS allowed differentiation of fibrinolysis level in subjects during intense exercise, as well as parameters of fatty acid metabolism specifically related either to performance or to training levels. Furthermore, unexpected correlated evolutions of molecular species were highlighted by this method, showing that 2D spectrometry may also be used for experimental investigations on human physiology. This study has demonstrated that 2D-COS may be used for the treatment of complex biological samples, such as plasma.