Altered type I collagen networking in osteoporotic human femoral head revealed by histomorphometric and Fourier transform infrared imaging correlated analyses

Abstract

Bone homeostasis is the equilibrium between organic and inorganic components of the extracellular matrix (ECM) and cells. Alteration of this balance has consequences on bone mass and architecture, resulting in conditions such as osteoporosis (OP). Given ECM protein mutual regulation and their effects on bone structure and mineralization, further insight into their expression is crucial to understanding bone biology under normal and pathological conditions. This study focused on Type I Collagen, which is mainly responsible for structural properties and mineralization of bone, and selected proteins implicated in matrix composition, mineral deposition, and cell‐matrix interaction such as Decorin, Osteocalcin, Osteopontin, Bone Sialoprotein 2, Osteonectin and Transforming Growth Factor beta. We developed a novel multidisciplinary approach in order to assess bone matrix in healthy and OP conditions more comprehensively by exploiting the Fourier Transform Infrared Imaging (FTIRI) technique combined with histomorphometry, Sirius Red staining, immunohistochemistry, and Western Blotting. This innovatory procedure allowed for the analysis of superimposed tissue sections and revealed that the alterations in OP bone tissue architecture were associated with warped Type I Collagen structure and deposition but not with changes in the total protein amount. The detected changes in the expression and/or cooperative or antagonist role of Decorin, Osteocalcin, Osteopontin, and Bone Sialoprotein‐2 indicate the deep impact of these NCPs on collagen features of OP bone. Overall, our strategy may represent a starting point for designing targeted clinical strategies aimed at bone mass preservation and sustain the FTIRI translational capability as upcoming support for traditional diagnostic methods.

Preeclampsia Correlates with an Increase in Cannabinoid Receptor 1 Levels Leading to Macromolecular Alterations in Chorionic Villi of Term Placenta

“…Here, we have studied the collagen I deposition in the chorionic villi of term placenta with a novel approach that combines the histological, histomorphometric, and hyperspectral analyses. Our findings demonstrate not only a significant increase in collagen I deposition in the preeclamptic villi, but also remarkable alterations in the collagen secondary structures: the assessment of the Amide III band (mainly attributed to collagen [ 33 , 34 , 36 ]) showing higher levels of collagen α chain and collagen triple helix in the pathological villi. Indeed, villous stroma has been described as the main placental compartment affected by the preeclampsia, being fibrosis of the villous stroma one of the most important features of this disease [ 7 ].…”

“…The average IR spectra of CTRL and PRE experimental groups are reported in Figure 3 , both in absorbance (continuous colored lines) and in second derivative (dotted black lines) modes in the 3050–2800 cm −1 , 1800–1500 cm −1 , and 1330–1100 cm −1 spectral ranges. Labels along the second derivative spectra indicate the most relevant IR bands: 2960 cm −1 and 2870 cm −1 (asymmetric and symmetric stretching vibrations of CH 3 groups); 2925 cm −1 and 2850 cm −1 (asymmetric and symmetric stretching vibrations of CH 2 groups); 1740 cm −1 (stretching vibration of C=O ester moieties in triglycerides and phospholipids); 1660 cm −1 and 1635 cm −1 (Amide I band components of proteins, AI) [ 29 , 30 , 31 ]; 1555 cm −1 and 1540 cm −1 (Amide II band components of proteins, AII) [ 29 , 30 , 31 , 32 ]; 1320 cm −1 (collagen’s α-helix secondary structures) [ 33 , 34 , 35 ]; 1284 cm −1 and 1240 cm −1 (collagen’s triple helix) [ 33 , 34 , 35 ]; 1204 cm −1 (collagen’s amino acids lateral chains) [ 33 , 34 , 35 , 36 ]; 1172 cm −1 phosphodiester bond (COP) [ 34 ] and 1130 cm −1 [ 32 ].…”

“…In that regard, the FTIRI analysis of tissue samples allows a 2D morpho-chemical correlation between the histological and spectroscopic data by topographically detecting changes in the biochemical composition and/or conformation of the biomolecules of interest, on the same tissue section and without any label. Moreover, FTIRI is a valuable and reliable tool for the study of the alterations in the secondary structure of proteins (including collagen) as biomarkers of some pathological conditions, by the thorough spectral analysis of Amide bands [ 34 , 36 ]. In this study, immunohistochemistry was carried out to analyze the specific levels of the endocannabinoid receptors in the CV, and by combining this technique with histomorphometry and a high-throughput technique, the FTIRI, we have investigated their potential link to the macromolecular alterations occurring in the CV of preeclamptic placenta.…”

In vivo effects of biosilica and spongin-like collagen scaffolds on the healing process in osteoporotic rats

“…Bone is unique in connective tissue healing because it heals entirely by cellular regeneration and the production of a mineral matrix rather than just collagen deposition known as scar (KIM et al, 2020;MARX, 2007). Moreover, type I collagen primarily provides structural and mechanical support, acting as a natural scaffold for the other extracellular matrix proteins beyond their core purpose in mineral deposition initiation (LICINI et al, 2022). For the quantitative collagen analysis, an increase of type I collagen for BS and of type III collagen for BS/SPG were found.…”

New insights on collagen structural organization and spatial distribution around dental implants: a comparison between machined and laser-treated surfaces

“…Fourier Transform Infrared Imaging (FTIRI) spectroscopy is a well assessed and label-free tool for studying non-homogeneous biological samples such as tissues and cells [ 37 , 38 ]. In fact, the coupling between infrared spectroscopy and visible microscopy and the development of array detectors able to reach a spatial resolution down to a few microns, let obtain high-resolution IR images which simultaneously provide reliable information on the biomolecular composition and structural organization of several macromolecules, including proteins and collagen [ 17 , 39 ]. Recently, FTIRI has been successfully applied for exploring the structural organization of collagen in soft and hard tissues and interesting results have been obtained [ 37 , 38 ].…”