Morphology Of Collagen Fibers Research Articles

Label‐Free Detection of Breast Phyllodes Tumors Based on Multiphoton Microscopy

ABSTRACTPhyllodes tumors (PTs) are rare breast stroma neoplasms, and their accurate identification at various stages is essential for personalized patient treatment. In this study, multiphoton microscopy (MPM) with two‐photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging was used for label‐free detection and differentiation of PTs and normal breast tissue. An automated image processing strategy was developed to quantify changes in collagen fiber morphology within the stroma and boundary of PTs, establishing optical diagnostic characteristics of PTs using MPM. The results demonstrated that MPM could be used for the detection of different stages of PTs, and the morphological alterations in collagen fibers could serve as critical indicators of PT malignancy, offering new insights for the diagnosis and grading of benign, borderline, and malignant PTs. It lays the groundwork for the future application of compact MPM for the rapid detection and diagnosis of PTs.

Transcriptomic analysis reveals the mechanism of isorhamnetin in the treatment of diabetes mellitus erectile dysfunction

PurposeExploring the therapeutic effect and mechanism of isorhamnetin in the treatment of DMED. MethodsUsing a high glucose environment to induce endothelial cells damage in the corpus cavernosum, and combining with intervention agents such as ferroptosis inhibitors to observe the process of cell damage and repair, evaluating cell status through CCK-8 and DAPI; To establish the STZ-induced diabetes rat model and detect the erectile function and tissue changes; Perform transcriptomic sequencing on rat models and samples treated with isorhamnetin to analyze differentially expressed genes and their GO functions; Identify critical pathways by combining with the ferroptosis database; Flow cytometry was used to detect ROS and mitochondrial membrane potential, and RT-PCR was used to verify gene expression, Seahorse detects mitochondrial oxygen consumption rate, revealing the mechanism of action of isorhamnetin. ResultsFerroptosis inhibitors and isorhamnetin can effectively reverse the damage of corpus cavernosum endothelial cells induced by high glucose and ferroptosis agonists. Isorhamnetin has the ability to reinstate the erectile function of diabetic rats, while enhancing the quantity of endothelial cells and refining the morphology of collagen fibers. Immunohistochemistry revealed that ferroptosis existed in the penis tissue of diabetes rats. Transcriptomic analysis showed that isorhamnetin improves gene expression in DM rats by regulating genes such as GFER, IGHM, GPX4 and HMOX1, involving multiple pathways and biological processes. Flow cytometry and RT-PCR confirmed that isorhamnetin can reduce reactive oxygen species levels, restore essential gene expression, improve mitochondrial membrane potential, and alleviate oxidative stress and ferroptosis. Seahorse detection found that isorhamnetin can restore mitochondrial oxygen consumption rate. ConclusionIsorhamnetin attenuates high glucose damage to cavernous endothelial cells by inhibiting ferroptosis and oxidative stress, restores erectile function and improves tissue morphology in diabetic rats, and its multi-pathway and multi-targeting regulatory mechanism suggests that it is promising to be an effective drug for the treatment of DMED.

Effects of lactic acid etching on immediate and aged bond strength of resin-dentin bonding interface.

To investigate the effects of lactic acid etching on the immediate and aged bond strength of the resin-dentin bonding interface, the resin-dentin bonding interface was evaluated 24 hours and 6 months later. A total of 42 isolated third molars were randomly divided into 6 experimental groups according to different lactate concentration (35%, 40%, 45%) and acid etching time (30 s, 45 s), with 37% phosphoric acid etching 15 s as a control. In each group, dentin samples were etched under different acidic conditions and bonded with Adper Single Bond 2 (3M ESPE) as directed. The immediate group was immediately stored in deionized water at 37 °C for 24 h, and the aging group was stored in artificial saliva at 37 °C for 6 months. Immediate and aged bond strengths were measured by a micro-tensile tester, and the specimen fracture surface was observed under a microscope. 14 isolated third molars were randomly divided into 7 groups, and each group was etched with acid. Collagen fibers morphology in dentin was examined after gradient dehydration with ethanol by scanning electron microscopy (SEM). Statistically, there was no difference between the resin-dentin immediate bonding strength of 35% lactic acid for 30 s and 37% phosphoric acid for 15 s, but the aged bond strength was greater than that of the phosphoric acid group. According to scanning electron microscope observations, the collagen fiber morphology in 35% and 40% lactate etching dentin 30 s groups was relatively intact compared with other groups. In conclusion, 35% lactic acid etching of dentin 30 s ensures both immediate and aged resin-dentin bond strength.

Multiphoton excited polymerized biomimetic models of collagen fiber morphology to study single cell and collective migration dynamics in pancreatic cancer

The respective roles of aligned collagen fiber morphology found in the extracellular matrix (ECM) of pancreatic cancer patients and cellular migration dynamics have been gaining attention because of their connection with increased aggressive phenotypes and poor prognosis. To better understand how collagen fiber morphology influences cell-matrix interactions associated with metastasis, we used Second Harmonic Generation (SHG) images from patient biopsies with Pancreatic ductal adenocarcinoma (PDAC) as models to fabricate collagen scaffolds to investigate processes associated with motility. Using the PDAC BxPC-3 metastatic cell line, we investigated single and collective cell dynamics on scaffolds of varying collagen alignment. Collective or clustered cells grown on the scaffolds with the highest collagen fiber alignment had increased E-cadherin expression and larger focal adhesion sites compared to single cells, consistent with metastatic behavior. Analysis of single cell motility revealed that the dynamics were characterized by random walk on all substrates. However, examining collective motility over different time points showed that the migration was super-diffusive and enhanced on highly aligned fibers, whereas it was hindered and sub-diffusive on un-patterned substrates. This was further supported by the more elongated morphology observed in collectively migrating cells on aligned collagen fibers. Overall, this approach allows the decoupling of single and collective cell behavior as a function of collagen alignment and shows the relative importance of collective cell behavior as well as fiber morphology in PDAC metastasis. We suggest these scaffolds can be used for further investigations of PDAC cell biology. Statement of significancePancreatic ductal adenocarcinoma (PDAC) has a high mortality rate, where aligned collagen has been associated with poor prognosis. Biomimetic models representing this architecture are needed to understand complex cellular interactions. The SHG image-based models based on stromal collagen from human biopsies afford the measurements of cell morphology, cadherin and focal adhesion expression as well as detailed motility dynamics. Using a metastatic cell line, we decoupled the roles of single cell and collective cell behavior as well as that arising from aligned collagen. Our data suggests that metastatic characteristics are enhanced by increased collagen alignment and that collective cell behavior is more relevant to metastatic processes. These scaffolds provide new insight in this disease and can be a platform for further experiments such as testing drug efficacy.

SHG Fiberscopy Assessment of Collagen Morphology and Its Potential for Breast Cancer Optical Histology.

This study is to investigate the feasibility of our recently developed nonlinear fiberscope for label-free in situ breast tumor detection and lymph node status assessment based on second harmonic generation (SHG) imaging of fibrillar collagen matrix with histological details. The long-term goal is to improve the current biopsy-based cancer paradigm with reduced sampling errors. In this pilot study we undertook retrospective SHG imaging study of ex vivo invasive ductal carcinoma human biopsy tissue samples, and carried out quantitative image analysis to search for collagen structural signatures that are associated with the malignance of breast cancer. SHG fiberscopy image-based quantitative assessment of collagen fiber morphology reveals that: 1) cancerous tissues contain generally less extracellular collagen fibers compared with tumor-adjacent normal tissues, and 2) collagen fibers in lymph node positive biopsies are more aligned than lymph node negative counterparts. The results demonstrate the promising potential of our SHG fiberscope for in situ breast tumor detection and lymph node involvement assessment and for offering real-time guidance during ongoing tissue biopsy.

Evaluation of Collagen Morphology and Eosinophils in Different Grades of Oral Squamous Cell Carcinoma Using Hematoxylin and Eosin and Congo Red Stains – A Pilot Study

Abstract Background: Oral squamous cell carcinoma (OSCC) exhibits dysplastic features in the epithelium and connective tissue which constitute tumor microenvironment. Eosinophils are granulocytic cells which impart inflammatory response and cell death, thereby producing a great role in the regulation and progression of tumors. The morphology of collagen fibers also varies on the progression of oral cancer. Aims: The present study aims at evaluating collagen morphology and amount of eosinophil in different grades of OSCC using hematoxylin and eosin (H and E) and Congo red stains. Settings and Design: The present study includes histopathologically proven cases of 15 OSCC subclassified into five cases per each group. Subjects and Methods: Both H and E and Congo red staining were done for five cases per grades of OSCC and viewed by two observers in zigzag pattern. Statistical Analysis Used: Statistical analysis was done using ANOVA test and interobserver variability by kappa statistics. Results: P < 0.001 was obtained based on the ANOVA test and P value of eosinophils among different grades was statistically significant. Conclusions: The present study concludes that stroma will change from dense to loose and increase in number of eosinophils as carcinoma progresses.

Kartogenin-loaded polyvinyl alcohol/nano-hydroxyapatite composite hydrogel promotes tendon-bone healing in rabbits after anterior cruciate ligament reconstruction.

Accumulating evidence supports the role of cartilage tissue engineering in cartilage defect repair, but the biological function has yet to be fully explained. In this work, kartogenin (KGN), an emerging chondroinductive nonprotein small molecule, was incorporated into a composite hydrogel of polyvinyl alcohol/nano-hydroxyapatite (PVA/n-HA) to fabricate an appropriate microenvironment for tendon-bone healing after anterior cruciate ligament (ACL) reconstruction. KGN/PVA/n-HA composite hydrogel scaffolds were prepared by in situ synthesis and physical adsorption, followed by characterization under a scanning electron microscope. The scaffolds were transplanted into healthy New Zealand White (NZW) rabbits. It was confirmed that KGN/PVA/n-HA scaffolds were successfully prepared and exhibited good supporting properties and excellent biocompatibility. Unilateral ACL reconstruction was constructed with tendon autograft in NZW rabbits, and the morphology and diameter of collagen fiber were analyzed. The scaffolds were shown to promote ACL growth and collagen fiber formation. Furthermore, microcomputerized tomography analysis and bone formation histology were performed to detect new bone formation. KGN/PVA/n-HA scaffolds effectively alleviated cartilage damage and prevented the occurrence of osteoarthritis. Meanwhile, ligament-bone healing and bone formation were observed in the presence of KGN/PVA/n-HA scaffolds. In conclusion, these results suggest that the KGN/PVA/n-HA scaffolds can facilitate tendon-bone healing after ACL reconstruction and might be considered novel hydrogel biomaterials in cartilage tissue engineering.

Optical second-harmonic generation imaging for identifying gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors arising in the digest tract. It brings a challenge to diagnosis because it is asymptomatic clinically. It is well known that tumor development is often accompanied by the changes in the morphology of collagen fibers. Nowadays, an emerging optical imaging technique, second-harmonic generation (SHG), can directly identify collagen fibers without staining due to its noncentrosymmetric properties. Therefore, in this study, we attempt to assess the feasibility of SHG imaging for detecting GISTs by monitoring the morphological changes of collagen fibers in tumor microenvironment. We found that collagen alterations occurred obviously in the GISTs by comparing with normal tissues, and furthermore, two morphological features from SHG images were extracted to quantitatively assess the morphological difference of collagen fibers between normal muscular layer and GISTs by means of automated image analysis. Quantitative analyses show a significant difference in the two collagen features. This study demonstrates the potential of SHG imaging as an adjunctive diagnostic tool for label-free identification of GISTs.

Region- and layer-specific investigations of the human menisci using SHG imaging and biaxial testing.

In this paper, we examine the region- and layer-specific collagen fiber morphology via second harmonic generation (SHG) in combination with planar biaxial tension testing to suggest a structure-based constitutive model for the human meniscal tissue. Five lateral and four medial menisci were utilized, with samples excised across the thickness from the anterior, mid-body, and posterior regions of each meniscus. An optical clearing protocol enhanced the scan depth. SHG imaging revealed that the top samples consisted of randomly oriented fibers with a mean fiber orientation of 43.3 o . The bottom samples were dominated by circumferentially organized fibers, with a mean orientation of 9.5 o . Biaxial testing revealed a clear anisotropic response, with the circumferential direction being stiffer than the radial direction. The bottom samples from the anterior region of the medial menisci exhibited higher circumferential elastic modulus with a mean value of 21MPa. The data from the two testing protocols were combined to characterize the tissue with an anisotropic hyperelastic material model based on the generalized structure tensor approach. The model showed good agreement in representing the material anisotropy with a mean r 2 = 0.92.

Characteristics of Collagen Changes in Small Intestine Anastomoses Induced by High-Frequency Electric Field Welding.

High-frequency electric field welding-induced tissue fusion has been explored as an advanced surgical method for intestinal anastomoses; however, intrinsic mechanisms remain unclear. The aim of this study was to investigate microcosmic changes of collagen within the fusion area, with various parameters. Ex vivo small intestine was fused with mucosa-mucosa. Four levels of compressive pressure (100 kPa, 150 kPa, 200 kPa, 250 kPa) were applied for 10 s in order to fuse the colons under a power level of 140 W. Then, collagen fibers of the fusion area were examined by fibrillar collagen alignment and TEM. Three levels of power (90 W, 110 W, 140 W) and three levels of time (5 s, 10 s, 20 s) were applied in order to fuse colons at 250 kPa, and then collagen within the fusion area was examined by Raman spectroscopy. Fibrillar collagen alignment analysis showed that with the increase in compression pressure, alignment of the collagen in the fusion area gradually increased, and the arrangement of collagen fibers tended to be consistent, which was conducive to the adhesion of collagen fibers. TEM showed that pressure changed the distribution and morphology of collagen fibers. Raman spectroscopy showed that increased power and time within a certain range contributed to collagen cross linking. Peak positions of amide I band and amide III band changed. These results suggested that higher power and a longer amount of time resulted in a decrease in non-reducible cross links and an increase in reducible cross links. Compression pressure, power, and time can affect the state of collagen, but the mechanisms are different. Compressive pressure affected the state of collagen by changing its orientation; power and time denatured collagen by increasing temperature and improved the reducible cross linking of collagen to promote tissue fusion.

Assessing the roles of collagen fiber morphology and matrix stiffness on ovarian cancer cell migration dynamics using multiphoton fabricated orthogonal image-based models

Ovarian cancer remains the deadliest of the gynecological cancers, where this arises from poor screening and imaging tools that can detect early disease, and also limited understanding of the structural and functional aspects of the tumor microenvironment. To gain insight into the underlying cellular dynamics, we have used multiphoton excited fabrication to create Second Harmonic Generation (SHG) image-based orthogonal models from collagen/GelMA that represent both the collagen matrix morphology and stiffness (∼2–8 kPa) of normal ovarian stroma and high grade serous ovarian cancers (HGSOC). These scaffolds are used to study migration/cytoskeletal dynamics of normal (IOSE) and ovarian cancer (OVCA433) cell lines. We found that the highly aligned fiber morphology of HGSOC promotes aspects of motility (motility coefficient, motility, and focal adhesion expression) through a contact guidance mechanism and that stiffer matrix further promotes these same processes through a mechanosensitive mechanism, where these trends were similar for both normal and cancer cells. However, cell specific differences were found on these orthogonal models relative to those providing only morphology, showing the importance of presenting both morphology and stiffness cues. Moreover, we found increased cadherin expression and decreased cell alignment only for cancer cells on scaffolds of intermediate modulus suggesting different stiffness-dependent mechanotransduction mechanisms are engaged. This overall approach affords decoupling the roles of matrix morphology, stiffness and cell genotype and affords hypothesis testing of the factors giving rise to disease progression and metastasis. Further, more established fabrication techniques cannot simultaneously reproduce both the 3D collagen fiber morphology and stiffness. Statement of significanceOvarian cancer metastasizes when lesions are small, where cells exfoliate from the surface of the ovary and reattach at distal sites in the peritoneum. The adhesion/migration dynamics are not well understood and there is a need for new 3D in vitro models of the extracellular matrix to study the biology. Here we use multiphoton excited crosslinking to fabricate ECM orthogonal models that represent the collagen morphology and stiffness in human ovarian tissues. These are then used to study ovarian cancer cell migration dynamics and we found that contact guidance and a mechanosensitive response and cell genotype all combine to affect the behavior. These models provide insight into disease etiology and progression not readily possible by other fabrication methods.

Effect of High Pressure/Heating Combination on the Structure and Texture of Chinese Traditional Pig Trotter Stewed with Soy Sauce

In order to clarify the effect of a high pressure/heating combination on the texture of Chinese traditional pig trotter with soy sauce, textural parameters (springiness, chewiness, hardness, and gumminess), the secondary structures, cross-links, decorin (DCN), glycosaminoglycans (GAGs) levels, and the histochemical morphology of collagen fibers under different treatments (0.1 MPa, 150 MPa, 300 MPa, 0.1 MPa + 50 °C, 150 MPa + 50 °C, and 300 MPa + 50 °C) were assessed. At room temperature, the 150 and 300 MPa treatments increased the hardness and chewiness of the pig trotter with weak denaturation of collagen proteins compared with the control group. Textural parameters were improved at 300 MPa + 50 °C, accompanied by an ultrastructural collapse of collagen fibers, the reduction in cross-links, DCN and GAGs levels, and unfolded triple-helix structure. We concluded that the positive effects on the textural parameters of pig trotters by a combination of treatments could be attributed to the collapse of collagen structure.

The Texture Change of Chinese Traditional Pig Trotter with Soy Sauce during Stewing Processing: Based on a Thermal Degradation Model of Collagen Fibers.

In order to clarify the influence of the thermal degradation of collagen fibers on the texture profile analysis (TPA) parameters of pig trotter stewed with soy sauce (PTSWSS), TPA (springiness, chewiness, hardness, and gumminess), the secondary structures, the cross-linkage, decorin (DCN) and glycosaminoglycan (GAG) levels, and the histochemical morphology of collagen fibers during the stewing process (0, 30, 60, 120 min) were assessed. The springiness and hardness increased after 30 min of stewing, along with the denaturation of collagen proteins. TPA parameters improved with the prolonged stewing times of 60 and 120 min, along with the ultra-structural dissolution of collagen fibers, and a substantial reduction in cross-linkage, DCN, and GAG levels, and the unfolded triple-helix structure. This study concluded that the TPA parameters of PTSWSS were dependent on the stewing time, and that the improvement in TPA parameters with longer stewing time could primarily be attributed to the thermal degradation of collagen fibers.

Collagen and elastic fiber remodeling in the pregnant mouse myometrium†.

The myometrium undergoes progressive tissue remodeling from early to late pregnancy to support fetal growth and transitions to the contractile phase to deliver a baby at term. Much of our effort has been focused on understanding the functional role of myometrial smooth muscle cells, but the role of extracellular matrix is not clear. This study was aimed to demonstrate the expression profile of sub-sets of genes involved in the synthesis, processing, and assembly of collagen and elastic fibers, their structural remodeling during pregnancy, and hormonal regulation. Myometrial tissues were isolated from non-pregnant and pregnant mice to analyze gene expression and protein levels of components of collagen and elastic fibers. Second harmonic generation imaging was used to examine the morphology of collagen and elastic fibers. Gene and protein expressions of collagen and elastin were induced very early in pregnancy. Further, the gene expressions of some of the factors involved in the synthesis, processing, and assembly of collagen and elastic fibers were differentially expressed in the pregnant mouse myometrium. Our imaging analysis demonstrated that the collagen and elastic fibers undergo structural reorganization from early to late pregnancy. Collagen and elastin were differentially induced in response to estrogen and progesterone in the myometrium of ovariectomized mice. Collagen was induced by both estrogen and progesterone. By contrast, estrogen induced elastin, but progesterone suppressed its expression. The current study suggests progressive extracellular matrix remodeling and its potential role in the myometrial tissue mechanical function during pregnancy and parturition.

Native human collagen type I provides a viable physiologically relevant alternative to xenogeneic sources for tissue engineering applications: A comparative in vitro and in vivo study.

Xenogeneic sources of collagen type I remain a common choice for regenerative medicine applications due to ease of availability. Human and animal sources have some similarities, but small variations in amino acid composition can influence the physical properties of collagen, cellular response, and tissue remodeling. The goal of this work is to compare human collagen type I-based hydrogels versus animal-derived collagen type I-based hydrogels, generated from commercially available products, for their physico-chemical properties and for tissue engineering and regenerative medicine applications. Specifically, we evaluated whether the native human skin type I collagen could be used in the three most common research applications of this protein: as a substrate for attachment and proliferation of conventional 2D cell culture; as a source of matrix for a 3D cell culture; and as a source of matrix for tissue engineering. Results showed that species and tissue specific variations of collagen sources significantly impact the physical, chemical, and biological properties of collagen hydrogels including gelation kinetics, swelling ratio, collagen fiber morphology, compressive modulus, stability, and metabolic activity of hMSCs. Tumor constructs formulated with human skin collagen showed a differential response to chemotherapy agents compared to rat tail collagen. Human skin collagen performed comparably to rat tail collagen and enabled assembly of perfused human vessels in vivo. Despite differences in collagen manufacturing methods and supplied forms, the results suggest that commercially available human collagen can be used in lieu of xenogeneic sources to create functional scaffolds, but not all sources of human collagen behave similarly. These factors must be considered in the development of 3D tissues for drug screening and regenerative medicine applications.

Qingwei San treats oral ulcer subjected to stomach heat syndrome in db/db mice by targeting TLR4/MyD88/NF-\u03baB pathway

BackgroundQingwei San (QWS), one of classic Chinese Medicine prescripts, has been widely used to treat stomach heat syndrome which manifests oral ulcer (OU), periodontitis and upper gastrointestinal bleeding for seven hundred years. However, the therapeutic effects of QWS on diabetic OU subjected to stomach heat syndrome are still ambiguous. In the study, we investigated the pharmacological mechanisms.MethodsThe main components of QWS aqueous extract were analyzed by LC–MS, and potential pathways of QWS targeting OU were predicted by network pharmacology. The db/db mice were administered with the decoction of dried Zingiber officinale Rosc. rhizome combined with NaOH cauterization to establish the model of diabetic OU subjected to stomach heat syndrome. Subsequently, the model mice were treated with QWS, and OU wound healing status were recorded. The pathological changes of gastric tissue and oral mucosa were evaluated using hematoxylin–eosin staining, and the morphology of collagen fibers in oral mucosa was assessed by Masson staining. The levels of thromboxane B2 (TXB2), 6-Keto-prostaglandin F1α (6-keto-PGF1α), interleukin-1 β (IL-1β), IL-2, IL-6, tumor necrosis factor-α (TNF-α), β-endorphin (β-EP) and 5-Hydroxytryptamine (5-HT) were determined by ELISA assay. The protein expressions of Toll-like receptor 4 (TLR4), TNF receptor associated factor 6 (TRAF6), myeloid differentiation factor 88 (MyD88), inhibitor of NF-κB alpha (IκΒα), p-IκΒα and nuclear factor kappa-B (NF-κB) p65 were measured by Western Blotting.ResultsA total of 183 compounds in QWS were identified by LC–MS, and identified 79 bioactive compounds corresponded to 269 targets and 59 pathways. QWS high-dose treatment significantly reduced the level of TXB2 and the ratio of TXB2/6-keto-PGF1α. Meanwhile, it improved mucosal pathological morphology, and reduced the area of OU and local edema. Simultaneously, the levels of TNF-α, IL-1β, IL-6, IL-2 and 5-HT, and the expressions of TLR4, TRAF6, MyD88, p-IκΒα and NF-κB p65 were decreased.ConclusionQWS treatment facilitates the healing of OU, ameliorates pathological morphologies of gastric and oral mucosa and decreases the levels of pro-inflammatory cytokines in db/db mice subjected to stomach heat syndrome, whose mechanism may be associated with the inhibition of TLR4/MyD88/NF-κB signaling pathway to exert anti-inflammatory effects.

Impairment of esophageal skeletal muscle in type XIX collagen mutant mouse

Type XIX collagen is an extremely rare extracellular matrix collagen thought to be involved in the formation of basement membrane zones and is transiently expressed by differentiating muscle cells. Mice without collagen XIX exhibit an impaired muscle differentiation and function. Individual skeletal muscle fibers are ensheathed by a meshwork of collagen fibers comprising the endomysium. Such structures seem to play an important role in resisting imputes. Type XIX collagen-null mice have a poor survival, and surviving null mice exhibit a dilated esophagus after three months of age, especially in aged mice. We used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to examine the skeletal muscle morphology and reticular distribution of collagen fibers in the endomysium of the esophagus in mice. The aim of this research was to demonstrate the fine structures in the dilated portion of the esophagus in mutant mice. Our findings showed that the size and arrangement of skeletal muscle as well as the collagen fibrils of the endomysium in the dilated portion of the esophagus differed markedly from those in wild-type mice. In addition, skeletal abnormalities were seen in the non-dilated portion of the esophagus in the mutant mice. These findings suggest that type XIX collagen-containing fibrils influence morphogenesis during skeletal myogenesis in the murine esophagus.

Evaluation of Collagen Alterations in Early Precursor Lesions of High Grade Serous Ovarian Cancer by Second Harmonic Generation Microscopy and Mass Spectrometry.

Simple SummaryThe collagen architecture in the extracellular matrix (ECM) is highly remodeled in high grade serous ovarian cancer (HGSOC). Many of these tumors begin in the fallopian tubes (FT) before metastasizing to the ovaries and it is important to study ECM alterations in carcinogenesis. Here, we used Second Harmonic Generation (SHG) microscopy to classify changes in the collagen fiber morphology in normal FT, and precursor pure p53 signatures and serous tubal intraepithelial carcinoma (STICs) in tissues with no HGSOC. Using a machine learning approach based on image features, we were able to discriminate the tissue groups with good classification accuracy. We additionally performed mass spectrometry analysis of normal and HGSOC tissues to associate the differential expression of collagen isoforms with fiber morphology alterations. This work provides new insights into ECM remodeling in early stage HGSOC and suggests the combined use of SHG microscopy and mass spectrometry as a new diagnostic/prognostic approach.Background: The collagen architecture in high grade serous ovarian cancer (HGSOC) is highly remodeled compared to the normal ovary and the fallopian tubes (FT). We previously used Second Harmonic Generation (SHG) microscopy and machine learning to classify the changes in collagen fiber morphology occurring in serous tubal intraepithelial carcinoma (STIC) lesions that are concurrent with HGSOC. We now extend these studies to examine collagen remodeling in pure p53 signatures, STICs and normal regions in tissues that have no concurrent HGSOC. This is an important distinction as high-grade disease can result in distant collagen changes through a field effect mechanism. Methods: We trained a linear discriminant model based on SHG texture and image features as a classifier to discriminate the tissue groups. We additionally performed mass spectrometry analysis of normal and HGSOC tissues to associate the differential expression of collagen isoforms with collagen fiber morphology alterations. Results: We quantified the differences in the collagen architecture between normal tissue and the precursors with good classification accuracy. Through proteomic analysis, we identified the downregulation of single α-chains including those for Col I and III, where these results are consistent with our previous SHG-based supramolecular analyses. Conclusion: This work provides new insights into ECM remodeling in early ovarian cancer and suggests the combined use of SHG microscopy and mass spectrometry as a new diagnostic/prognostic approach.

Effects of Long-Term Methotrexate, Infliximab, and Tocilizumab Administration on Bone Microarchitecture and Tendon Morphology in Healthy Wistar Rats.

ObjectiveRheumatic diseases are associated with bone loss, both systemic and periarticular, and tendon abnormalities. The aim of this study is to examine the effect of three antiarthritic drugs, methotrexate, an anti-folate metabolite; infliximab, a Tumor Necrosis Factor-alpha (TNF-α) inhibitor; and tocilizumab, an antibody against Interleukin-6 (IL-6) receptor, on bone microarchitecture and tendon morphology in the absence of an inflammatory state.Materials and methodsThirty-five, 8- to 9-week-old, male, Wistar rats were randomly allocated into five groups: negative control (CTRL), vehicle (VEH), methotrexate (MTX), infliximab (INFX), and tocilizumab (TCZ). After 8 weeks of antiarthritic drug intraperitoneal administration, animals were euthanized and rat tibiae and patellar tendons were histologically examined.ResultsAll sections exhibited normal bone microarchitecture. Histological scores in all groups corresponded to normal bone mineral density. No no apparent differences in tenocyte morphology and architecture of collagen fibers were observed.ConclusionsThe results of this study indicate that long-term administration of methotrexate, infliximab, and tocilizumab had no effect on bone microarchitecture and tendon morphology in rats in the absence of an inflammatory condition.

Picrosirius-Polarization Method for Collagen Fiber Detection in Tendons: A Mini-Review.

Although the structure and composition of collagen have been studied by polarized light microscopy since the early 19th century, many studies and reviews have paid little or no attention to the morphological problems of histopathological diagnosis. The morphology of collagen fibers is critical in guiding mechanical and biological properties in both normal and pathological tendons. Highlighting the organization and spatial distribution of tendon‐containing collagen fibers can be very useful for visualizing a tendon's ultrastructure, biochemical and indirect mechanical properties, which benefits other researchers and clinicians. Picrosirius red (PSR) staining, relying on the birefringence of collagen fibers, is one of the best understood histochemical methods that can highly and specifically underline fibers better than other common staining techniques when combined with polarized light microscopy (PLM). Polarized light microscopy provides complementary information about collagen fibers, such as orientation, type and spatial distribution, which is important for a comprehensive assessment of collagen alteration in a tendon. Here, this brief review serves as a simplistic and important primer to research developments in which differential staining of collagen types by the Picrosirius‐polarization method is increasing in diverse studies of the medical field, mainly in the assessment of the morphology, spatial distribution, and content of collagen in tendons.