Caracterização de biomarcadores espectrais relacionados ao diagnóstico de asma

Abstract

Introduction: Asthma is a common and a major health burden worldwide. Asthma diagnosis actually relies on a combination of clinical factors, bronchodilator responsiveness in lung function, and airway inflammation. Consequently, the search for a non-invasive, reagent-free, and specific platform to asthma diagnosis is needed for clinical practice. Fourier transform infrared (FTIR) spectroscopy provides for sensitive analysis of complex biological samples and demonstrated to be a robust tool for accurate detection of disease. Objective: This study explores whether FTIR can produce distinct spectral profiles in saliva of asthmatic patients comparing to healthy subjects. Material and methods: Ten asthma patients and ten healthy subjects were selected to collect saliva. The salivary profile was analyzed by ATR-FTIR spectroscopy and the vibrational modes were evaluated for diagnostic ability by ROC curve. Results: The intensity of eight vibrational modes (two of original spectra and six of second derivative spectra) showed significant changes between asthma patients and health subjects. In original spectra bands 2344 cm-1 and 1341cm-1, area absorbance were increased (p < 0.05) in asthma patients compared to matched-controls. ROC analysis for these vibrational modes showed: 2344 cm-1: AUC 0.80, sensitivity 70%, specificity 90%; 1341cm-1: AUC 0.77 sensitivity 70%, specificity 80%. At second derivative spectra, intensity of peak in six vibrational modes of saliva (1629, 1156, 1119, 1076, 745 and 619cm-1) were reduced (p < 0.05) in asthma compared to control group and ROC analysis for them showed: 1629 cm-1: AUC 0.83, sensitivity 80%, specificity 70%; 1156 and 1119 cm-1: AUC 0.80, sensitivity of 70%, specificity 80%; 1076 cm-1: AUC 0.85, sensitivity 70%, specificity 90%; 745 cm-1: AUC 0.88, sensitivity 70%, specificity 90% and 619 cm-1: AUC 0.87, sensitivity 70%, specificity 100%. Conclusion: Altogether, attenuated total reflection ATR-FTIR spectroscopy may provide a useful tool to complement analysis in the clinical routine for the diagnosis of asthma.