FTIR spectroscopy of chronic venous leg ulcer exudates: an approach to spectral healing marker identification

CERUSICO, NICOLAS ABEL; AYBAR, JUAN PABLO; LOPEZ, SILVANA AIDE; MOLINA, SIVLIA GRACIELA; CHAVEZ JARA, ROMINA; SESTO CABRAL, EUGENIA MARIA; VALDEZ, JUAN CARLOS; BEN ALTABEF, AIDA; RAMOS VERNIERI, ALBERTO NICOLAS

ANALYST

ROYAL SOC CHEMISTRY

Año: 2018 vol. 1 p. 1 - 24

0003-2654

Chronic venous leg ulcer (CVLU) arises as a chronic venous insufficiency complication and is a major cause of morbidity throughout the world. Our hypothesis is that CVLU exudate composition is a biochemical representation of wound clinical state. Then, Fourier Transform Infrared (FTIR) spectroscopy could be a useful and less-invasive technique to study the clinical state of the ulcer. For this, the aim of this work was to perform a spectral characterization of exudate from CVLU using FTIR spectroscopy to identify potential healing markers. 45 exudate samples from CVLU, 95% of the strains isolated from CVLU in planktonic and biofilm phenotypes and other related biological samples as human plasma, serum, urine, blood cells, urea, creatinine, glucose and albumin were studied by FTIR spectroscopy. According to vibration frequency of biomolecules (lipids, protein, nucleic acids and carbohydrates) characteristic bonds at infrared region, different spectral windows were selected and spectral areas of each window were measured. Besides, Savitzky-Golay second derivative were obtained for all spectra and peaks from each standardized window were detected. FTIR spectroscopy allowed to identify sample types (exudate, plasma, serum, urine) as each one present a unique relative composition and ratios ranges. Also, this technique could be useful to identify bacteria at phenotypic-ulcer state and allows to differentiate if bacteria are in biofilm or planktonic form which is unlikely by conventional methods. In this work we found some spectral markers (areas, peaks) that allow to identify several parameters in exudate as: a) Total cellularity, b) Inflammatory cells load, c) Bacterial load, d) Fibrin amount, e) Inflammatory proteins. Because the measured areas or founded peaks are concentration-dependent this method could also serve to measure them. Therefore, FTIR spectroscopy could be useful to evaluate patient evolution as all these exudate parameters represent critical negative markers for wound healing.