Calcification of aortic human valves studied in situ by Raman microimaging: following mineralization from small grains to big deposits

Abstract

A Raman microimaging‐based approach has been used in the current study to evaluate formation and progression of calcification in situ in human stenotic aortic valves obtained during surgical valve replacement. The capability of the method to visualize distribution of the calcified deposits resulted in structural characterization of deposits in the various phases of development. A high spatial resolution of the method along with the confocal depth profiling enabled to identify extremely small salt inclusions (of ca. 0.5 µm in diameter), formed probably at the very early stage of calcification. Structurally, these inclusions are built from an octacalcium phosphate‐like compound that during grains' growth transforms into tricalcium phosphate, mixed with the salt containing the acidic phosphate groups (HPO42−) and, finally, into stable B‐type hydroxyapatite that is the only salt present in large‐area calcium salt deposits. Copyright © 2013 John Wiley & Sons, Ltd.

Different Calcification Stage in Each Cusp of a Calcified Tricuspid Aortic Valve

“…The band at 1,069 cm −1 was assigned to B-type carbonated HA. 4 The progressive calcification from β-tricalcium phosphate (as a precursor) to HA and then to B-type carbonated HA in the RCC is clearly seen (Figure 2B). The Raman spectra of the noncoronary cusp (NCC) were divided into two groups: 945-and 970-cm −1 bands (traces 1,2) and 959-and 1,070-cm −1 bands (traces 3-5; Figure 2C), suggesting that the calcification process in the NCC predominantly involved the formation of B-type carbonated HA (major) and β-tricalcium phosphate (minor).…”

“…Both bands were attributed to β-tricalcium phosphate. 4 Interestingly, the Raman spectral shift occurred from 1,658 cm −1 (cis-configuration of unsaturated lipids) to 1,662 cm −1 , and then to 1,664 cm −1 (trans-configuration of unsaturated lipids). 3 This is the first evidence of conversion of unsaturated lipids from cis to trans in the LCC.…”

Raman microspectroscopy of human aortic valves: investigation of the local and global biochemical changes associated with calcification in aortic stenosis

“…[28][29][30][31][32] In our previous experiments we used Raman microimaging to investigate the inorganic deposits in the tissue, describing the chemical structure, distribution, size and shape of calcium phosphate inclusions in stenotic aortic valves. 33 The aim of this study was to determine the biochemical alterations of the tissue in stenotic aortic valves, particularly in the vicinity of inorganic salts.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part VIII

“…They found that the capability of the method to visualize distributions of calcified deposits resulted in structural characterization of deposits in the various phases of development. [103] Terentis et al show that confocal Raman microspectroscopy can discriminate live human metastatic melanoma and skin fibroblast cells. Using chemometrics (PCA and LDA-CV), they were able to successfully discriminate two skin cancer-relevant cell lines while detecting different amounts of nucleic acids, lipids, and proteins in distinct intracellular regions, further underscoring its potential as a clinical diagnostic tool.…”

“…Pilarczyk and coworkers used in situ Raman microimaging to study calcification of aortic human valves by following mineralization from small grains to large deposits. They found that the capability of the method to visualize distributions of calcified deposits resulted in structural characterization of deposits in the various phases of development . Terentis et al .…”