Plasma biomarkers of pulmonary hypertension identified by Fourier transform infrared spectroscopy and principal component analysis

Abstract

The main goal of this study was to find specific plasma spectral markers associated with pulmonary arterial hypertension (PAH) induced by monocrotaline injection in rats. FTIR was used to monitor biochemical changes in plasma caused by PAH as compared with the systemic hypertension induced by partial ligation on the left artery and with the control group. Both pathologies, systemic and pulmonary hypertension, induced a unique response in the biochemical content of plasma, mainly related to the composition and secondary structure of plasma proteins. For PAH, β-pleated sheet components of plasma proteins were identified whereas the protein composition in systemic hypertension was dominated by unordered structures. In addition, a higher concentration of tyrosine-rich proteins was found in plasma in PAH than in systemic hypertension. The differences between both pathologies were identified also in terms of lipid composition/metabolism as well as in the content of RNA and glucose, suggesting that lipid peroxidation appears upon pulmonary hypertension development. In summary, this work demonstrates that FTIR spectroscopy supported by principal component analysis (PCA) has the potential to become a fast and non-destructive method for biochemical characterization of plasma that consequently could have a diagnostic significance in pulmonary hypertension.

A possible Fourier transform infrared‐based plasma fingerprint of angiotensin‐converting enzyme inhibitor‐induced reversal of endothelial dysfunction in diabetic mice

“…As PER 10 mg/kg, but not PER 2 mg/kg, improved endothelial function the unsaturation level of plasma fatty acids seemed to reflect endothelial status, and most likely oxidative stress. Interestingly, our analysis of systemic and pulmonary hypertensions indicated a similar decrease of lipid unsaturation level in plasma that could also be relevant to the presence of endothelial dysfunction in these diseases [25,27].…”

“…In summary, our results demonstrated that the combination of chemometric analysis and FTIR spectroscopic signature of the macromolecular vibrations found in 0.5 μL dried plasma films reflected closely metabolic disturbances of diabetes and can possibly be used for a rapid monitoring the metabolic response of the diabetes treatment . However, in contrast to other pathologies, in which pattern of FTIR plasma changes seemed to clearly reflect vascular wall pathology, for example, in NO‐deficient mice or pulmonary hypertension , and could be possibly used for monitoring of vasoprotective treatment, FTIR spectra in diabetes were dominated by massive diabetes‐related metabolical dysfunction that masks and overweighs the subtle endothelial‐related effects. However, in each of these 3 pathologies such as systemic hypertension, pulmonary hypertension and diabetes that are linked to endothelial dysfunction, alterations in the secondary structure of proteins are visible, suggesting that this type of changes may indeed constitute the reliable FTIR‐based fingerprint of endothelial dysfunction.…”

“…Fourier transform infrared (FTIR) spectroscopy to study blood‐based samples is not a new concept and there are several reports showing a usefulness of infrared spectroscopy for diagnosis, monitoring progression of diseases and their treatment by investigation of erythrocytes , leukocytes , platelets , plasma , and serum . Instead of the quantification of a single or a few biomarkers, on which most of the blood tests rely, the total biochemical composition of a sample is analyzed in a single and rapid measurement of plasma IR spectrum including peptides, proteins, lipids, RNA and others.…”

“…Three replicates of each plasma sample (0.5 μL) were manually spotted onto CaF 2 windows, and left to dry in a temperature-controlled laboratory (24 C) for approximately 5 min. A similar approach has been successfully employed in several FTIR studies on plasma and serum [25,27,28,34,[41][42][43][44][45].…”

Ultra-filtration of human serum for improved quantitative analysis of low molecular weight biomarkers using ATR-IR spectroscopy

“…The IR spectrum contains rich and specific information about the molecular composition of the human serum which, coupled to advanced multivariate analysis tools, could deliver accurate diagnostics. Recent systematic studies have demonstrated the potential of IR serum based diagnosis with different data mining approaches such as Principal Components Analysis (PCA), PCA coupled to Linear Discriminant Analysis (PCA-LDA), Random Forest or Support Vector Machine (SVM) [26][27][28][29][30] . However, the development of spectroscopic technologies with medical perspectives needs to align with clinical requirements to enable clinical translation of these promising technologies 31 .…”