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Topic:Collagen
Collagen is a structural protein found abundantly in the connective tissues of horses, including skin, tendons, ligaments, and cartilage. It contributes to the strength and elasticity of these tissues, playing a significant role in maintaining structural integrity. Collagen fibers are composed of amino acid chains, primarily glycine, proline, and hydroxyproline, which form a triple helix structure. In horses, collagen is involved in various physiological processes, including tissue repair and regeneration. Changes in collagen composition and structure can be associated with conditions such as joint disorders and tendon injuries. This page compiles peer-reviewed research studies and scholarly articles that explore the synthesis, function, and clinical implications of collagen in equine health.
Immunogenicity of intensively decellularized equine carotid arteries is conferred by the extracellular matrix protein collagen type VI. The limited biocompatibility of decellularized scaffolds is an ongoing challenge in tissue engineering. Here, we demonstrate the residual immunogenicity of an extensively decellularized equine carotid artery (dEAC(intens)) and identify the involved immunogenic components. EAC were submitted to an elaborated intensified decellularization protocol with SDS/sodium desoxycholate for 72 h using increased processing volumes (dEAC(intens)), and compared to dEAC(ord) prepared by an ordinary protocol (40 h, normal volumes). Matrix integrity was checked via correlative volumetric visualization which rev...
Concomitant inhibition of primary equine bronchial fibroblast proliferation and differentiation by selective β2-adrenoceptor agonists and dexamethasone. Altered airway cell proliferation plays an important role in the pathogenesis of human bronchial asthma and chronic obstructive pulmonary disease (COPD) as well as the equine recurrent airway obstruction (RAO) with consistent changes, i.e. narrowing the airway wall, explained by proliferation and differentiation of fibroblasts. In permanent cell lines, it has been suggested that β2-adrenoceptor agonists and glucocorticoids regulate cell proliferation via the β2-adrenoceptor pathway; indeed, no study was carried out in fresh isolated primary equine bronchial fibroblasts (EBF). We characterize...
Airway collagen and elastic fiber content correlates with lung function in equine heaves. The consequences on lung function and inflammation of alterations in the extracellular matrix affecting the peripheral airway wall in asthma are largely unknown. We hypothesized that remodeling of collagen and elastic fibers in the peripheral airway wall leads to airway obstruction and contributes to neutrophilic airway inflammation. Animals used were six heaves-affected horses and five controls. Large peripheral lung biopsies were obtained from horses with heaves in clinical remission (Baseline) and during disease exacerbation and from age-matched controls. The area of collagen and elastic fi...
Regulation of Tenomodulin Expression Via Wnt/β-catenin Signaling in Equine Bone Marrow-derived Mesenchymal Stem Cells. Tenomodulin has been recognized as a biomarker for tendon differentiation, and its gene expression is regulated by several transcription factors including Scleraxis and Mohawk. In this study, we found a novel regulatory mechanism of tenomodulin expression. Equine bone marrow-derived mesenchymal stem cells (BMSCs) in monolayer culture showed a low mRNA level of tenomodulin in comparison with the level in the tendon. When cultured in collagen gel containing a glycogen synthase kinase-3 (GSK-3) inhibitor (BIO), expression of tenomodulin in BMSCs increased up to the level in the tendon. Participat...
Three-dimensional culture and transforming growth factor beta3 synergistically promote tenogenic differentiation of equine embryo-derived stem cells. The natural reparative mechanisms triggered by tendon damage often lead to the formation of biomechanically inferior scar tissue that is prone to re-injury. Before the efficient application of stem cell-based regenerative therapies, the processes regulating tenocyte differentiation should first be better understood. Three-dimensional (3D) growth environments under strain and the exogenous addition of transforming growth factor beta3 (TGF-β3) have separately been shown to promote tendon differentiation. The aim of this study was to determine the ability of both of these factors to induce tendo...
Culture of equine fibroblast-like synoviocytes on synthetic tissue scaffolds towards meniscal tissue engineering: a preliminary cell-seeding study. Introduction. Tissue engineering is a new methodology for addressing meniscal injury or loss. Synovium may be an ideal source of cells for in vitro meniscal fibrocartilage formation, however, favorable in vitro culture conditions for synovium must be established in order to achieve this goal. The objective of this study was to determine cellularity, cell distribution, and extracellular matrix (ECM) formation of equine fibroblast-like synoviocytes (FLS) cultured on synthetic scaffolds, for potential application in synovium-based meniscal tissue engineering. Scaffolds included open-cell poly-L-l...
In vivo effects of phenylbutazone on inflammation and cartilage-derived biomarkers in equine joints with acute synovitis. Although phenylbutazone (PBZ) is commonly used in equine orthopaedic practice, little is known about its in vivo effects on joint inflammation and cartilage turnover. This study investigates the effects of PBZ on inflammatory parameters, matrix metalloproteinase (MMP) activity and cartilage biomarkers in equine joints with acute synovitis. In a two-period cross-over study, transient synovitis was induced at T = 0 h in the middle carpal joint of seven ponies by lipopolysaccharide (LPS) injection. Ponies received PBZ (2 mg/kg PO twice daily) or placebo for 1 week, starting at T = 2 h. Ar...
Connective tissue disorders in domestic animals. Though soft tissue disorders have been recognized and described to some detail in several types of domestic animals and small mammals for some years, not much progress has been made in our understanding of the biochemical basis and pathogenesis of these diseases in animals. Ehlers-Danlos syndrome described in dogs already in 1943 and later in cats affects mainly skin in these animals. The involved skin is thin and hyperextensible with easily inflicted injuries resulting in hemorrhagic wounds and atrophic scars. Joint laxity and dislocation common in people are less frequently found in dogs. No...
Connective tissue disorders in domestic animals. Though soft tissue disorders have been recognized and described to some detail in several types of domestic animals and small mammals for some years, not much progress has been made in our understanding of the biochemical basis and pathogenesis of these diseases in animals. Ehlers-Danlos syndrome described in dogs already in 1943 and later in cats affects mainly skin in these animals. The involved skin is thin and hyperextensible with easily inflicted injuries resulting in hemorrhagic wounds and atrophic scars. Joint laxity and dislocation common in people are less frequently found in dogs. No...
Regenerative therapies for equine degenerative joint disease: a preliminary study. Degenerative joint disease (DJD) is a major cause of reduced athletic function and retirement in equine performers. For this reason, regenerative therapies for DJD have gained increasing interest. Platelet-rich plasma (PRP) and mesenchymal stem cells (MSCs) were isolated from a 6-year-old donor horse. MSCs were either used in their native state or after chondrogenic induction. In an initial study, 20 horses with naturally occurring DJD in the fetlock joint were divided in 4 groups and injected with the following: 1) PRP; 2) MSCs; 3) MSCs and PRP; or 4) chondrogenic induced MSCs and PRP. The ho...
Expression and activity of collagenases in the digital laminae of horses with carbohydrate overload-induced acute laminitis. Matrix metalloproteinases (MMP) are hypothesized to degrade structurally important components of the laminar extracellular matrix (ECM) in horses with laminitis. Objective: To compare levels of expression of stromelysin-1 (MMP-3), collagenases (MMP-1, -13), and membrane type-MMPs (MMP-14, -15, -16), and the distribution of their ECM substrates, in laminae of healthy horses and horses with carbohydrate overload laminitis. Methods: Twenty-five adult horses. Methods: Gene and protein expression were determined in extracts of laminae using real-time quantitative polymerase chain reaction and Weste...
Polymorphisms in TNC and COL5A1 genes are associated with risk of superficial digital flexor tendinopathy in National Hunt Thoroughbred racehorses. To explore whether genetic susceptibility is a potential risk factor for superficial digital flexor (SDF) tendinopathy in Thoroughbred (TB) racehorses. Objective: To identify informative single nucleotide polymorphisms (SNPs) that capture genetic diversity across a range of candidate genes and to investigate, in a case-control study, their association with SDF tendinopathy in UK National Hunt TB racehorses in training. Methods: Case-control candidate gene association study. Methods: This study used in silico gene assembly and DNA sequencing to screen candidate genes for SNPs. Seven candidate g...
The fibrous tapetum of the horse eye. The tapetum lucidum is a light-reflective tissue in the eyes of many animals. Many ungulates have a fibrous tapetum. The horse has one of the largest eyes of any living animal and also has excellent vision in low-light environments. This study aimed to clarify the macroscopic tapetal shape, relationship between the tapetal thickness and the degree of pigmentation of the retinal pigment epithelium (RPE), spatial relationship between the visual streak and the tapetum, and wavelength of the light reflected from the tapetum in the horse. Macroscopically, weak light revealed the tapetum as a horizo...
Tensile properties in collagen-rich tissues of Quarter Horses with hereditary equine regional dermal asthenia (HERDA). Hereditary equine regional dermal asthenia (HERDA) is an autosomal recessive disorder of Quarter Horses characterised by skin fragility. Horses with HERDA have a missense mutation in peptidyl-prolyl cis-trans isomerase B (PPIB), which encodes cyclophilin B and alters folding and post translational modifications of fibrillar collagen. Objective: The study aimed to test the hypothesis that tendons, ligaments and great vessels, which, like skin, are rich in fibrillar collagen, will also have abnormal biomechanical properties in horses with HERDA. Methods: Ex vivo biomechanical study comparing...
Effects of exercise on markers of venous remodeling in lungs of horses. To determine the effects of 2 weeks of intense exercise on expression of markers of pulmonary venous remodeling in the caudodorsal and cranioventral regions of the lungs of horses. Methods: 6 horses. Methods: Tissue samples of the caudodorsal and cranioventral regions of lungs were obtained before and after conditioning and 2 weeks of intense exercise. Pulmonary veins were isolated, and a quantitative real-time PCR assay was used to determine mRNA expression of matrix metalloproteinase-2 and -9, tissue inhibitor of metalloproteinase-1 and -2, collagen type I, tenascin-C, endothelin-1, platelet...
Foetal and postnatal equine articular cartilage development: magnetic resonance imaging and polarised light microscopy. Adult articular cartilage (AC) has a well described multizonal collagen structure. Knowledge of foetal AC organisation and development may provide a prototype for cartilage repair strategies, and improve understanding of structural changes in developmental diseases such as osteochondrosis (OC). The objective of this study was to describe normal development of the spatial architecture of the collagen network of equine AC using 1.5 T magnetic resonance imaging (MRI) and polarised light microscopy (PLM), at sites employed for cartilage repair studies or susceptible to OC. T2-weighted fast-spin e...
Induction of cytochrome P450 enzymes in primary equine hepatocyte culture. In this study, we established cell culture conditions for primary equine hepatocytes allowing cytochrome P450 enzyme (CYP) induction experiments. Hepatocytes were isolated after a modified method of Bakala et al. (2003) and cultivated on collagen I coated plates. Three different media were compared for their influence on morphology, viability and CYP activity of the hepatocytes. CYP activity was evaluated with the fluorescent substrate 7-benzyloxy-4-trifluoromethylcoumarin. Induction experiments were carried out with rifampicin, dexamethasone or phenobarbital. Concentration-response curves for...
In vitro mesenchymal trilineage differentiation and extracellular matrix production by adipose and bone marrow derived adult equine multipotent stromal cells on a collagen scaffold. Directed differentiation of adult multipotent stromal cells (MSC) is critical for effective treatment strategies. This study was designed to evaluate the capability of equine MSC from bone marrow (BMSC) and adipose tissue (ASC) on a type I collagen (COLI) scaffold to undergo chondrogenic, osteogenic and adipogenic differentiation and form extracellular matrix (ECM) in vitro. Following determination of surface antigen expression, MSC were loaded into scaffolds in a perfusion bioreactor and loading efficiency was quantified. Cell-scaffold constructs were assessed after loading and 7, 14 and 21 d...
Imaging horse tendons using multimodal 2-photon microscopy. Injuries and damage to tendons plague both human and equine athletes. At the site of injuries, various cells congregate to repair and re-structure the collagen. Treatments for collagen injury range from simple procedures such as icing and pharmaceutical treatments to more complex surgeries and the implantation of stem cells. Regardless of the treatment, the level of mechanical stimulation incurred by the recovering tendon is crucial. However, for a given tendon injury, it is not known precisely how much of a load should be applied for an effective recovery. Both too much and too little loading...
The use of bioinspired alterations in the glycosaminoglycan content of collagen-GAG scaffolds to regulate cell activity. The design of biomaterials for regenerative medicine can require biomolecular cues such as growth factors to induce a desired cell activity. Signal molecules are often incorporated into the biomaterial in either freely-diffusible or covalently-bound forms. However, biomolecular environments in vivo are often complex and dynamic. Notably, glycosaminoglycans (GAGs), linear polysaccharides found in the extracellular matrix, are involved in transient sequestration of growth factors via charge interactions. Biomaterials mimicking this phenomenon may offer the potential to amplify local biomolecular...
Tenascin-C Expression in Equine Tendon-derived Cells During Proliferation and Migration. In vitro cell studies might be a useful tool for studying tendon pathology, but no suitable in vitro models exist for tendon disorders. The purpose of this study was to confirm whether cell scratch culture using tendon-derived fibroblasts can provide a suitable in vitro tendon disorder model. Extracellular matrix components were examined immunohistochemically in tendon tissue, and then their related gene expression levels were analyzed by conventional reverse transcription polymerase chain reaction (RT-PCR) and/or quantitative real-time RT-PCR in tissues and cells. Collagen type I (Col I), col...
Functional characterization of detergent-decellularized equine tendon extracellular matrix for tissue engineering applications. Natural extracellular matrix provides a number of distinct advantages for engineering replacement orthopedic tissue due to its intrinsic functional properties. The goal of this study was to optimize a biologically derived scaffold for tendon tissue engineering using equine flexor digitorum superficialis tendons. We investigated changes in scaffold composition and ultrastructure in response to several mechanical, detergent and enzymatic decellularization protocols using microscopic techniques and a panel of biochemical assays to evaluate total protein, collagen, glycosaminoglycan, and deoxyribo...
Effects of serum and autologous conditioned serum on equine articular chondrocytes treated with interleukin-1β. To compare the effects of autologous equine serum (AES) and autologous conditioned serum (ACS) on equine articular chondrocyte metabolism when stimulated with recombinant human (rh) interleukin (IL)-1β. Methods: Articular cartilage and nonconditioned and conditioned serum from 6 young adult horses. Methods: Cartilage samples were digested, and chondrocytes were isolated and formed into pellets. Chondrocyte pellets were treated with each of the following: 10% AES, 10% AES and rhIL-1β, 20% AES and rhIL-1β, 10% ACS and rhIL-1β, and 20% ACS and rhIL-1β, and various effects of these treatments...
Tenogenic differentiation of equine adipose-tissue-derived stem cells under the influence of tensile strain, growth differentiation factors and various oxygen tensions. Mesenchymal stem cells have become extremely interesting for regenerative medicine and tissue engineering in the horse. Stem cell therapy has been proven to be a powerful and successful instrument, in particular for the healing of tendon lesions. We pre-differentiated equine adipose-tissue-derived stem cells (ASCs) in a collagen I gel scaffold by applying tensile strain, growth differentiation factors (GDFs) and various oxygen tensions in order to determine the optimal conditions for in vitro differentiation toward the tenogenic lineage. We compared the influence of 3% versus 21% oxygen tensio...
Scaffold effects on osteogenic differentiation of equine mesenchymal stem cells: an in vitro comparative study. The in vitro viability, osteogenic differentiation, and mineralization of four different equine mesenchymal stem cells (MSCs) from bone marrow, periosteum, muscle, and adipose tissue are compared, when they are cultured with different collagen-based scaffolds or with fibrin glue. The results indicate that bone marrow cells are the best source of MSCs for osteogenic differentiation, and that an electrochemically aggregated collagen gives the highest cell viability and best osteogenic differentiation among the four kinds of scaffolds studied.
Equine articular chondrocytes on MACT scaffolds for cartilage defect treatment. Treatment of cartilage defects poses challenging problems in human and veterinary medicine, especially in horses. This study examines the suitability of applying scaffold materials similar to those used for human cartilage regeneration on equine chondrocytes. Chondrocytes gained from biopsies of the talocrural joint of three horses were propagated in 2D culture and grown on two different scaffold materials, hyaluronan (HYAFF®) and collagen (BioGide®), and evaluated by light and electron microscopy. The equine chondrocytes developed well in both types of materials. They were vital and physiol...
Composite growth factor supplementation strategies to enhance tenocyte bioactivity in aligned collagen-GAG scaffolds. Biomolecular environments encountered in vivo are complex and dynamic, with combinations of biomolecules presented in both freely diffusible (liquid-phase) and sequestered (bound to the extracellular matrix) states. Strategies for integrating multiple biomolecular signals into a biomimetic scaffold provide a platform to simultaneously control multiple cell activities, such as motility, proliferation, phenotype, and regenerative potential. Here we describe an investigation elucidating the influence of the dose and mode of presentation (soluble, sequestered) of five biomolecules (stromal cell-de...
Development of an in vitro model of injury-induced osteoarthritis in cartilage explants from adult horses through application of single-impact compressive overload. To develop an in vitro model of cartilage injury in full-thickness equine cartilage specimens that can be used to simulate in vivo disease and evaluate treatment efficacy. Methods: 15 full-thickness cartilage explants from the trochlear ridges of the distal aspect of the femur from each of 6 adult horses that had died from reasons unrelated to the musculoskeletal system. Methods: To simulate injury, cartilage explants were subjected to single-impact uniaxial compression to 50%, 60%, 70%, or 80% strain at a rate of 100% strain/s. Other explants were left uninjured (control specimens). All speci...
Immunolocalization of collagens (I and III) and cartilage oligomeric matrix protein in the normal and injured equine superficial digital flexor tendon. This is a descriptive study of tendon pathology with different structural appearances of repair tissue correlated to immunolocalization of cartilage oligomeric matrix protein (COMP) and type I and III collagens and expression of COMP mRNA. The material consists of nine tendons from seven horses (5-25 years old; mean age of 10 years) with clinical tendinopathy and three normal tendons from horses (3, 3, and 13 years old) euthanized for non-orthopedic reasons. The injured tendons displayed different repair-tissue appearances with organized and disorganized fibroblastic regions as well as areas o...
Age-dependent effects of systemic administration of oxytetracycline on the viscoelastic properties of rat tail tendons as a mechanistic basis for pharmacological treatment of flexural limb deformities in foals. To describe the effect of systemically administered oxytetracycline on the viscoelastic properties of rat tail tendon fascicles (TTfs) to provide a mechanistic rationale for pharmacological treatment of flexural limb deformities in foals. Methods: TTfs from ten 1-month-old and ten 6-month-old male Sprague-Dawley rats. Methods: 5 rats in each age group were administered oxytetracycline (50 mg/kg, IP, q 24 h) for 4 days. The remaining 5 rats in each age group served as untreated controls. Five days after initiation of oxytetracycline treatment, TTfs were collected and their viscoelastic properti...
