scholarly journals Murine Metatarsus Bone and Joint Collagen-I Fiber Morphologies and Networks Studied With SHG Multiphoton Imaging

2021 ◽  
Vol 9 ◽  
Author(s):  
Martin Vielreicher ◽  
Aline Bozec ◽  
Georg Schett ◽  
Oliver Friedrich
Keyword(s):  
Rheumatoid Arthritis ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Chronic Inflammatory Disease ◽  
Collagen I ◽  
Bone Architecture ◽  
Fiber Types ◽  
Label Free ◽  
Fiber Morphology ◽  
Collagen Network

Chronic inflammatory disease of bones and joints (e.g., rheumatoid arthritis, gout, etc.), but also acute bone injury and healing, or degenerative resorptive processes inducing osteoporosis, are associated with structural remodeling that ultimately have impact on function. For instance, bone stability is predominantly orchestrated by the structural arrangement of extracellular matrix fibrillar networks, i.e., collagen-I, -IV, elastin, and other proteins. These components may undergo distinct network density and orientation alterations that may be causative for decreased toughness, resilience and load bearing capacity or even increased brittleness. Diagnostic approaches are usually confined to coarse imaging modalities of X-ray or computer tomography that only provide limited optical resolution and lack specificity to visualize the fibrillary collagen network. However, studying collagen structure at the microscopic scale is of considerable interest to understand the mechanisms of tissue pathologies. Multiphoton Second Harmonic Generation (SHG) microscopy, is able to visualize the sterical topology of the collagen-I fibrillar network in 3D, in a minimally invasive and label-free manner. Penetration depths exceed those of conventional visible light imaging and can be further optimized through employing decalcification or optical clearing processing ex vivo. The goal of this proof-of-concept study was to use SHG and two-photon excited fluorescence (2-PEF) imaging to mainly characterize the fibrillary collagen organization within ex vivo decalcified normal mouse metatarsus bone and joint. The results show that the technique resolved the fibrillar collagen network of complete bones and joints with almost no artifacts and enabled to study the complex collagen-I networks with various fiber types (straight, crimped) and network arrangements of mature and woven bone with high degree of detail. Our imaging approach enabled to identify cavities within both cortical and trabecular bone architecture as well as interfaces with sharply changing fiber morphology and network structure both within bone, in tendon and ligament and within joint areas. These possibilities are highly advantageous since the technology can easily be applied to animal models, e.g., of rheumatoid arthritis to study structural effects of chronic joint inflammation, and to many others and to compare to the structure of human bone.

scholarly journals Multiscale molecular profiling of pathological bone resolves sexually dimorphic control of extracellular matrix composition

2021 ◽  
Vol 14 (3) ◽  
pp. dmm048116 ◽  
Author(s):  
Aikta Sharma ◽  
Alice Goring ◽  
Peter B. Johnson ◽  
Roger J. H. Emery ◽  
Eric Hesse ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Collagen Fibre ◽  
Matrix Composition ◽  
Label Free ◽  
Fibre Number ◽  
Backscattered Electron ◽  
Matrix Mineralisation

ABSTRACTCollagen assembly during development is essential for successful matrix mineralisation, which determines bone quality and mechanocompetence. However, the biochemical and structural perturbations that drive pathological skeletal collagen configuration remain unclear. Deletion of vascular endothelial growth factor (VEGF; also known as VEGFA) in bone-forming osteoblasts (OBs) induces sex-specific alterations in extracellular matrix (ECM) conformation and mineralisation coupled to vascular changes, which are augmented in males. Whether this phenotypic dimorphism arises as a result of the divergent control of ECM composition and its subsequent arrangement is unknown and is the focus of this study. Herein, we used murine osteocalcin-specific Vegf knockout (OcnVEGFKO) and performed ex vivo multiscale analysis at the tibiofibular junction of both sexes. Label-free and non-destructive polarisation-resolved second-harmonic generation (p-SHG) microscopy revealed a reduction in collagen fibre number in males following the loss of VEGF, complemented by observable defects in matrix organisation by backscattered electron scanning electron microscopy. This was accompanied by localised divergence in collagen orientation, determined by p-SHG anisotropy measurements, as a result of OcnVEGFKO. Raman spectroscopy confirmed that the effect on collagen was linked to molecular dimorphic VEGF effects on collagen-specific proline and hydroxyproline, and collagen intra-strand stability, in addition to matrix carbonation and mineralisation. Vegf deletion in male and female murine OB cultures in vitro further highlighted divergence in genes regulating local ECM structure, including Adamts2, Spp1, Mmp9 and Lama1. Our results demonstrate the utility of macromolecular imaging and spectroscopic modalities for the detection of collagen arrangement and ECM composition in pathological bone. Linking the sex-specific genetic regulators to matrix signatures could be important for treatment of dimorphic bone disorders that clinically manifest in pathological nano- and macro-level disorganisation.This article has an associated First Person interview with the first author of the paper.

scholarly journals Multiomic and quantitative label-free microscopy-based analysis of ex vivo culture and TGFbeta1 stimulation of human precision-cut lung slices

2019 ◽  
Author(s):  
Muzamil Majid Khan ◽  
Daniel Poeckel ◽  
Aliaksandr Halavatyi ◽  
Frank Stein ◽  
Johanna Vappiani ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Integrated Approach ◽  
Imaging Method ◽  
Fibrillar Collagen ◽  
Label Free ◽  
Ex Vivo Culture ◽  
And Function ◽  
Precision Cut Lung Slices

AbstractFibrosis can affect any organ resulting in the loss of tissue architecture and function with often life-threatening consequences. Pathologically, fibrosis is characterised by expansion of connective tissue due to excessive deposition of extracellular matrix proteins (ECM), including the fibrillar forms of collagen. A significant hurdle for discovering cures for fibrosis is the lack of suitable models and techniques to quantify mature collagen deposition in tissues. Here we have extensively characterized an ex-vivo cultured human lung derived, precision-cut lung slices model (hPCLS) using live fluorescence light microscopy as well as mass spectrometry-based techniques to obtain a proteomic and metabolomic fingerprint. Using an integrated approach of multiple readouts such as quantitative label-free Second Harmonic Generation (SHG) imaging to measure fibrillar collagen in the extracellular matrix and ELISA-based methods to measure soluble ECM biomarkers, we investigated TGFbeta1-mediated pro-fibrotic signalling in hPCLS. We demonstrate that hPCLS are viable and metabolically active with mesenchymal, epithelial, endothelial, and immune cells surviving for at least two weeks in ex vivo culture. Analysis of hPCLS-conditioned supernatants showed strong induction of ECM synthesis proteins P1NP and fibronectin upon TGFb stimulation. Importantly, this effect translated into an increased deposition of fibrillar collagen in ECM of cultured hPCLS as measured by a novel quantitative SHG-based imaging method only following addition of a metalloproteinase inhibitor (GM6001). Together the data show that an integrated approach of measuring soluble pro-fibrotic markers and quantitative SHG-based analysis of fibrillar collagen is a valuable tool for studying pro-fibrotic signalling and testing anti-fibrotic agents.

scholarly journals An integrated multiomic and quantitative label-free microscopy-based approach to study pro-fibrotic signalling in ex vivo human precision-cut lung slices

2020 ◽  
pp. 2000221
Author(s):  
Muzamil Majid Khan ◽  
Daniel Poeckel ◽  
Aliaksandr Halavatyi ◽  
Joanna Zukowska-Kasprzyk ◽  
Frank Stein ◽  
...  
Keyword(s):  
Immune Cell ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Integrated Approach ◽  
Fibrillar Collagen ◽  
Collagen Deposition ◽  
Label Free ◽  
Human Lung Tissue ◽  
Ecm Proteins ◽  
Precision Cut Lung Slices

Fibrosis can affect any organ resulting in the loss of tissue architecture and function with often life-threatening consequences. Pathologically, fibrosis is characterised by expansion of connective tissue due to excessive deposition of extracellular matrix proteins (ECM), including the fibrillar forms of collagen. A significant limitation for discovering cures for fibrosis is the availability of suitable human models and techniques to quantify mature fibrillar collagen deposition as close as possible to human physiological conditions. Here we have extensively characterised an ex vivo cultured human lung tissue-derived, precision-cut lung slices model (hPCLS) using label-free second harmonic (SHG) light microscopy to quantify fibrillar collagen deposition and mass spectrometry-based techniques to obtain a proteomic and metabolomic fingerprint of hPCLS in ex vivo culture.We demonstrate that hPCLS are viable and metabolically active with mesenchymal, epithelial, endothelial, and immune cell types surviving for at least 2 weeks in ex vivo culture. Analysis of hPCLS-conditioned supernatants showed a strong induction of pulmonary fibrosis-related ECM proteins upon TGFß1 stimulation. This upregulation of ECM proteins was not translated into an increased deposition of fibrillar collagen. In support of this observation, we revealed the presence of a pro-ECM degradation activity in our ex vivo cultures of hPCLS, inhibition of which by metalloproteinase inhibitor resulted in increased collagen deposition in response to TGFß1 stimulation. Together the data show that an integrated approach of measuring soluble pro-fibrotic markers alongside quantitative SHG-based analysis of fibrillar collagen is a valuable tool for studying pro-fibrotic signalling and testing antifibrotic agents.

scholarly journals Label-free imaging immune cells and collagen in atherosclerosis with two-photon and second harmonic generation microscopy

2016 ◽  
Vol 09 (01) ◽  
pp. 1640003 ◽  
Author(s):  
Chunqiang Li ◽  
Riikka K. Pastila ◽  
Charles P. Lin
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Immune Cells ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Label Free ◽  
Optical Signals ◽  
Two Photon

Atherosclerosis has been recognized as a chronic inflammation disease, in which many types of cells participate in this process, including lymphocytes, macrophages, dendritic cells (DCs), mast cells, vascular smooth muscle cells (SMCs). Developments in imaging technology provide the capability to observe cellular and tissue components and their interactions. The knowledge of the functions of immune cells and their interactions with other cell and tissue components will facilitate our discovery of biomarkers in atherosclerosis and prediction of the risk factor of rupture-prone plaques. Nonlinear optical microscopy based on two-photon excited autofluorescence and second harmonic generation (SHG) were developed to image mast cells, SMCs and collagen in plaque ex vivo using endogenous optical signals. Mast cells were imaged with two-photon tryptophan autofluorescence, SMCs were imaged with two-photon NADH autofluorescence, and collagen were imaged with SHG. This development paves the way for further study of mast cell degranulation, and the effects of mast cell derived mediators such as induced synthesis and activation of matrix metalloproteinases (MMPs) which participate in the degradation of collagen.

scholarly journals A method to analyze the influence of mechanical strain on dermal collagen morphologies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maximilian Witte ◽  
Michael Rübhausen ◽  
Sören Jaspers ◽  
Horst Wenck ◽  
Frank Fischer
Keyword(s):  
Mechanical Properties ◽  
Collagen Fiber ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Mechanical Strain ◽  
Collagen Fibers ◽  
Collagen Network ◽  
Skin Sample ◽  
Fiber Network ◽  
Dermal Collagen

AbstractCollagen fibers and their orientation play a major role in the mechanical behavior of soft biological tissue such as skin. Here, we present a proof-of-principle study correlating mechanical properties with collagen fiber network morphologies. A dedicated multiphoton stretching device allows for mechanical deformations in combination with a simultaneous analysis of its collagen fiber network by second harmonic generation imaging (SHG). The recently introduced Fiber Image Network Evaluation (FINE) algorithm is used to obtain detailed information about the morphology with regard to fiber families in collagen network images. To demonstrate the potential of our method, we investigate an isotropic and an anisotropic ex-vivo dorsal pig skin sample under quasi-static cyclic stretching and relaxation sequences. Families of collagen fibers are found to form a partially aligned collagen network under strain. We find that the relative force uptake is accomplished in two steps. Firstly, fibers align within their fiber families and, secondly, fiber families orient in the direction of force. The maximum alignment of the collagen fiber network is found to be determined by the largest strain. Isotropic and anisotropic samples reveal a different micro structural behavior under repeated deformation leading to a similar force uptake after two stretching cycles. Our method correlates mechanical properties with morphologies in collagen fiber networks.

scholarly journals Second harmonic generation microscopy is a novel technique for differential diagnosis of breast fibroepithelial lesions

2015 ◽  
Vol 68 (12) ◽  
pp. 1033-1035 ◽  
Author(s):  
Wai Jin Tan ◽  
Jie Yan ◽  
Shuoyu Xu ◽  
Aye Aye Thike ◽  
Boon Huat Bay ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Clinical Decision Making ◽  
Direct Detection ◽  
Second Harmonic ◽  
Collagen I ◽  
Tissue Array ◽  
Label Free ◽  
Phyllodes Tumours

Breast fibroepithelial lesions, including fibroadenomas and phyllodes tumours, are commonly encountered in clinical practice. As histological differences between these two related entities may be subtle, resulting in a challenging differential diagnosis, pathological techniques to assist the differential diagnosis of these two entities are of high interest. An accurate diagnosis at biopsy is important given corresponding implications for clinical decision-making including surgical extent and monitoring. Second harmonic generation (SHG) microscopy is a recently developed optical imaging technique capable of robust, powerful and unbiased label-free direct detection of collagen fibril structure in tissue without the use of antibodies. We constructed tissue microarrays emulating limited materials on biopsy to investigate quantitative collagen signal in fibroepithelial lesions using SHG microscopy. Archived formalin-fixed paraffin-embedded materials of 47 fibroepithelial lesions (14 fibroadenomas and 33 phyllodes tumours) were evaluated. Higher collagen signal on SHG microscopy was observed in fibroadenomas than phyllodes tumours on SHG imaging (p<0.001, area under the curve 0.859). At an automated threshold (2.5 million positive pixels), the sensitivity and specificity of the SHG microscopy for fibroadenoma classification was 71.4% and 84.4%, respectively. To corroborate these findings, we performed immunohistochemistry on tissue array sections using collagen I and III primary antibodies. Both collagen I and III immunohistochemical expressions were also significantly higher in fibroadenomas than in phyllodes tumours (p<0.001). In conclusion, label-free collagen quantitation on SHG microscopy is a novel imaging approach that can aid the differential diagnosis of fibroepithelial lesions.

scholarly journals Custom Multiphoton/Raman Microscopy Setup for Imaging and Characterization of Biological Samples

2019 ◽  
Vol 2 (2) ◽  
pp. 51 ◽  
Author(s):  
Marco Marchetti ◽  
Enrico Baria ◽  
Riccardo Cicchi ◽  
Francesco Saverio Pavone
Keyword(s):  
Laser Scanning ◽  
Ex Vivo ◽  
Second Harmonic ◽  
Biological Tissues ◽  
Molecular Organization ◽  
Chemical Information ◽  
Specific Information ◽  
Label Free ◽  
Wide Range ◽  
Experimental Apparatus

Modern optics offers several label-free microscopic and spectroscopic solutions which are useful for both imaging and pathological assessments of biological tissues. The possibility to obtain similar morphological and biochemical information with fast and label-free techniques is highly desirable, but no single optical modality is capable of obtaining all of the information provided by histological and immunohistochemical analyses. Integrated multimodal imaging offers the possibility of integrating morphological with functional-chemical information in a label-free modality, complementing the simple observation with multiple specific contrast mechanisms. Here, we developed a custom laser-scanning microscopic platform that combines confocal Raman spectroscopy with multimodal non-linear imaging, including Coherent Anti-Stokes Raman Scattering, Second-Harmonic Generation, Two-Photon Excited Fluorescence, and Fluorescence Lifetime Imaging Microscopy. The experimental apparatus is capable of high-resolution morphological imaging of the specimen, while also providing specific information about molecular organization, functional behavior, and molecular fingerprint. The system was successfully tested in the analysis of ex vivo tissues affected by urothelial carcinoma and by atherosclerosis, allowing us to multimodally characterize of the investigated specimen. Our results show a proof-of-principle demonstrating the potential of the presented multimodal approach, which could serve in a wide range of biological and biomedical applications.

scholarly journals Global Deletion of 11β-HSD1 Prevents Muscle Wasting Associated with Glucocorticoid Therapy in Polyarthritis

2021 ◽  
Vol 22 (15) ◽  
pp. 7828
Author(s):  
Justine M. Webster ◽  
Michael S. Sagmeister ◽  
Chloe G. Fenton ◽  
Alex P. Seabright ◽  
Yu-Chiang Lai ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Skeletal Muscle ◽  
Chronic Inflammation ◽  
Muscle Atrophy ◽  
Muscle Wasting ◽  
Ex Vivo ◽  
Glucocorticoid Therapy ◽  
Knock Out ◽  
Fiber Size ◽  
Anti Inflammatory

Glucocorticoids provide indispensable anti-inflammatory therapies. However, metabolic adverse effects including muscle wasting restrict their use. The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) modulates peripheral glucocorticoid responses through pre-receptor metabolism. This study investigates how 11β-HSD1 influences skeletal muscle responses to glucocorticoid therapy for chronic inflammation. We assessed human skeletal muscle biopsies from patients with rheumatoid arthritis and osteoarthritis for 11β-HSD1 activity ex vivo. Using the TNF-α-transgenic mouse model (TNF-tg) of chronic inflammation, we examined the effects of corticosterone treatment and 11β-HSD1 global knock-out (11βKO) on skeletal muscle, measuring anti-inflammatory gene expression, muscle weights, fiber size distribution, and catabolic pathways. Muscle 11β-HSD1 activity was elevated in patients with rheumatoid arthritis and correlated with inflammation markers. In murine skeletal muscle, glucocorticoid administration suppressed IL6 expression in TNF-tg mice but not in TNF-tg11βKO mice. TNF-tg mice exhibited reductions in muscle weight and fiber size with glucocorticoid therapy. In contrast, TNF-tg11βKO mice were protected against glucocorticoid-induced muscle atrophy. Glucocorticoid-mediated activation of catabolic mediators (FoxO1, Trim63) was also diminished in TNF-tg11βKO compared to TNF-tg mice. In summary, 11β-HSD1 knock-out prevents muscle atrophy associated with glucocorticoid therapy in a model of chronic inflammation. Targeting 11β-HSD1 may offer a strategy to refine the safety of glucocorticoids.

scholarly journals Optical Biomarkers for the Diagnosis of Osteoarthritis through Raman Spectroscopy: Radiological and Biochemical Validation Using Ex Vivo Human Cartilage Samples

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Paula Casal-Beiroa ◽  
Vanesa Balboa-Barreiro ◽  
Natividad Oreiro ◽  
Sonia Pértega-Díaz ◽  
Francisco J. Blanco ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Articular Cartilage ◽  
Ex Vivo ◽  
Cartilage Degradation ◽  
Calcium Pyrophosphate ◽  
Calcium Pyrophosphate Dihydrate ◽  
Label Free ◽  
Molecular Fingerprint ◽  
Human Cartilage ◽  
Biochemical Validation

Osteoarthritis (OA) is the most common rheumatic disease, characterized by progressive articular cartilage degradation. Raman spectroscopy (RS) has been recently proposed as a label-free tool to detect molecular changes in musculoskeletal tissues. We used cartilage samples derived from human femoral heads to perform an ex vivo study of different Raman signals and ratios, related to major and minor molecular components of articular cartilage, hereby proposed as candidate optical biomarkers for OA. Validation was performed against the radiological Kellgren–Lawrence (K-L) grading system, as a gold standard, and cross-validated against sulfated glycosaminoglycans (sGAGs) and total collagens (Hyp) biochemical contents. Our results showed a significant decrease in sGAGs (SGAGs, A1063 cm−1/A1004 cm−1) and proteoglycans (PGs, A1375 cm−1/A1004 cm−1) and a significant increase in collagen disorganization (ColD/F, A1245 cm−1/A1270 cm−1), with OA severity. These were correlated with sGAGs or Hyp contents, respectively. Moreover, the SGAGs/HA ratio (A1063 cm−1/A960 cm−1), representing a functional matrix, rich in proteoglycans, to a mineralized matrix-hydroxyapatite (HA), was significantly lower in OA cartilage (K-L I vs. III–IV, p < 0.05), whilst the mineralized to collagenous matrix ratio (HA/Col, A960 cm−1/A920 cm−1) increased, being correlated with K-L. OA samples showed signs of tissue mineralization, supported by the presence of calcium crystals-related signals, such as phosphate, carbonate, and calcium pyrophosphate dihydrate (MGP, A960 cm−1/A1004 cm−1, MGC, A1070 cm−1/A1004 cm−1 and A1050 cm−1/A1004 cm−1). Finally, we observed an increase in lipids ratio (IL, A1450 cm−1/A1670 cm−1) with OA severity. As a conclusion, we have described the molecular fingerprint of hip cartilage, validating a panel of optical biomarkers and the potential of RS as a complementary diagnostic tool for OA.

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