Analysis of platelets in hypertensive and normotensive individuals using Raman and Fourier transform infrared-attenuated total reflectance spectroscopies

Platelets of both healthy and hypertensive subjects were analyzed by Raman and Fourier transform infrared by attenuated total reflectance (FTIR-ATR) spectroscopies. We compared the average relative intensities of the main Raman peaks, the areas of convoluted bands in the amide I region, and the second derivative of the FTIR-ATR spectra. Key differences were found in the bands reflecting lipid content and protein structure. The Raman spectra exhibited statistically significant changes in the intensity of bands associated with CC stretching vibrations in the carbon chains of lipids (960 cm⁻¹) and the amide I band (centered at 1,658 cm⁻¹). The amide I deconvolution showed changes in the area percentages of the bands corresponding to different protein secondary structures, suggesting biochemical and protein conformational differences between healthy versus arterial hypertension platelets, which might be related to the platelet activation stage. An analysis by using the second derivative of the FTIR-ATR spectra, followed by deconvolution of amide regions support this observation, revealing differences in the amide II and amide I bands. Moreover, modifications observed in the phosphate-associated bands are possibly related to the phospholipids' behavior and the phosphorylation of proteins. Our results suggest interesting differences between the spectra of healthy versus hypertensive platelets, which may be mainly associated with biochemical changes at the cellular membrane level.