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Molecular structure of human aortic valve by µSR- FTIR microscopy

DOI: 10.1016/j.nimb.2017.06.021 DOI Help

Authors: Anna M. Borkowska (Institute of Nuclear Physics Polish Academy of Sciences) , Michal Nowakowski (Institute of Nuclear Physics Polish Academy of Sciences) , Grzegorz J. Lis (Jagiellonian University) , Katia Wehbe (Diamond Light Source) , Gianfelice Cinque (Diamond Light Source) , Wojciech M. Kwiatek (Institute of Nuclear Physics Polish Academy of Sciences)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nuclear Instruments And Methods In Physics Research Section B: Beam Interactions With Materials And Atoms , VOL 411 , PAGES 129-135

State: Published (Approved)
Published: July 2017
Diamond Proposal Number(s): 12573

Abstract: Aortic valve is a part of the heart most frequently affected by pathological processes in humans what constitute a very serious health problem. Therefore, studies of morphology and molecular microstructure of the AV are needed. µSR- FTIR spectroscopy and microscopy represent unique tools to study chemical composition of the tissue and to identify spectroscopic markers characteristic for structural and functional features. Normal AV reveals a multi-layered structure and the compositional and structural changes within particular layers may trigger degenerative processes within the valve. Thus, deep insight into the structure of the valve to understand pathological processes occurring in AV is needed. In order to identify differences between three layers of human AV, tissue sections of macroscopically normal AV were studied using µSR- FTIR spectroscopy in combination with histological and histochemical stainings. Tissue sections deposited onto CaF2 substrates were mapped and representative set of IR spectra collected from fibrosa, spongiosa and ventricularis were analysed by Principal Component Analysis (PCA) in the spectral range between 1850–1000 cm−1 and 3050–2750 cm−1. PCA revealed a layered molecular structure of the valve and it was possible to identify IR bands associated to different tissue parts. Spongiosa layer was well differentiated from other two layers mainly based on IR bands characteristic for the distribution of glycosaminoglycans (GAGs) in the tissue – like 1170 cm−1 (υas(C-O-S)) and 1380 cm−1 (acetyl amino group). Additionally, it was distinguished from fibrosa and ventricularis based on 1085 cm−1 and 1240 cm−1 bands characteristic for GAGs and for carbohydrates- ν(C-O) and ν(C-O-C) respectively and nucleic acids -νsym(PO2−) and νasym(PO2−) respectively, which were less specific for this layer. The use of µSR- FTIR spectroscopy demonstrated co-localization of GAGs and lipids in spongiosa layer what may indicate their contribution in the very early phase of aortic valve calcific degeneration.

Journal Keywords: Human aortic valve; Principal Component Analysis; µSR- FTIR spectroscopy and microscopy

Subject Areas: Biology and Bio-materials, Medicine, Physics

Instruments: B22-Multimode InfraRed imaging And Microspectroscopy