Expression of Estrogen Receptor Alpha and Evaluation of Histological Degeneration Scores in Fibroblasts of Hypertrophied Ligamentum Flavum: A Qualitative Study.

The most common spinal disorder in elderly is lumbar spinal stenosis (LSS), resulting partly from ligamentum flavum (LF) hypertrophy. Its pathophysiology is not completely understood. The present study wants to elucidate the role of estrogen receptor α (ER α) in fibroblasts of hypertrophied LF. LF samples of 38 patients with LSS were obtained during spinal decompression. Twelve LF samples from patients with disk herniation served as controls. Hematoxylin & Eosin (H&E) and Elastica stains and immunohistochemistry for ER α were performed. The proportions of fibrosis, loss and/or degeneration of elastic fibers and proliferation of collagen fibers were assessed according to the scores of Sairyo and Okuda. Group differences in the ER α and Sairyo and Okuda scores between patients and controls, male and female sex and absence and presence of additional orthopedic diagnoses were assessed with the Mann-Whitney U test. There was a tendency towards higher expression of ER α in LF fibroblasts in the hypertrophy group (p = 0.065). The Sairyo and Okuda scores were more severe for the hypertrophy group but, in general, not statistically relevant. There was no statistically relevant correlation between the expression of ER α and sex (p = 0.326). ER α expression was higher in patients with osteochondrosis but not statistically significant (p = 0.113). In patients with scoliosis, ER α expression was significantly lower (p = 0.044). LF hypertrophy may be accompanied by a higher expression of ER α in fibroblasts. No difference in ER α expression was observed regarding sex. Further studies are needed to clarify the biological and clinical significance of these findings.

Molecular Processes in Chondrocyte Biology.

Chondrocyte biology is a hot topic, because osteoarthritis (OA) is a serious problem in an aging society, but there are no fundamental therapeutic drugs [...].

Proteome Alterations in Equine Osteochondrotic Chondrocytes.

Osteochondrosis is a failure of the endochondral ossification that affects developing joints in humans and several animal species. It is a localized idiopathic joint disorder characterized by focal chondronecrosis and growing cartilage retention, which can lead to the formation of fissures, subchondral bone cysts, or intra-articular fragments. Osteochondrosis is a complex multifactorial disease associated with extracellular matrix alterations and failure in chondrocyte differentiation, mainly due to genetic, biochemical, and nutritional factors, as well as traumas. This study describes the main proteomic alterations occurring in chondrocytes isolated from osteochondrotic cartilage fragments. A comparative analysis performed on equine osteochondrotic and healthy chondrocytes showed 26 protein species as differentially represented. In particular, quantitative changes in the extracellular matrix, cytoskeletal and chaperone proteins, and in cell adhesion and signaling molecules were observed in osteochondrotic cells, compared to healthy controls. Functional group analysis annotated most of these proteins in "growth plate and cartilage development", while others were included in "glycolysis and gluconeogenesis", "positive regulation of protein import", "cell-cell adhesion mediator activity", and "mitochondrion nucleoid". These results may help to clarify some chondrocyte functional alterations that may play a significant role in determining the onset and progression of equine osteochondrosis and, being related, of human juvenile osteochondrosis.

Synovial Fluid Metabolites Differentiate between Septic and Nonseptic Joint Pathologies.

Osteoarthritis (OA), osteochondrosis (OC), and synovial sepsis in horses cause loss of function and pain. Reliable biomarkers are required to achieve accurate and rapid diagnosis, with synovial fluid (SF) holding a unique source of biochemical information. Nuclear magnetic resonance (NMR) spectroscopy allows global metabolite analysis of a small volume of SF, with minimal sample preprocessing using a noninvasive and nondestructive method. Equine SF metabolic profiles from both nonseptic joints (OA and OC) and septic joints were analyzed using 1D 1H NMR spectroscopy. Univariate and multivariate statistical analyses were used to identify differential metabolite abundance between groups. Metabolites were annotated via 1H NMR using 1D NMR identification software Chenomx, with identities confirmed using 1D 1H and 2D 1H 13C NMR. Multivariate analysis identified separation between septic and nonseptic groups. Acetate, alanine, citrate, creatine phosphate, creatinine, glucose, glutamate, glutamine, glycine, phenylalanine, pyruvate, and valine were higher in the nonseptic group, while glycylproline was higher in sepsis. Multivariate separation was primarily driven by glucose; however, partial-least-squares discriminant analysis plots with glucose excluded demonstrated the remaining metabolites were still able to discriminate the groups. This study demonstrates that a panel of synovial metabolites can distinguish between septic and nonseptic equine SF, with glucose the principal discriminator.

Zinc: the Other Suspected Environmental Factor in Kashin-Beck Disease in Addition to Selenium.

Kashin-Beck disease (KBD) is an endemic chronic osteochondral disease characterized by high prevalence, disability, and morbidity and is distributed from the northeast to the southwest in China, in some regions of Eastern Siberia in Russia, and in North Korea. Although the selenium deficiency etiological hypothesis for KBD has been proposed by scientists for decades, the idea that selenium deficiency is one of the most important environmental factors but not the primary and sole pathogenic factor for KBD has been widely accepted. Zn2+, which is closely involved in the synthesis of enzymes, nucleic acids, and proteins, is an essential microelement in vivo. A conundrum still exists in research on the relationship between Zn2+ and KBD due to inconsistent results, but it has been confirmed that Zn2+ can help repair metaphyseal lesions in patients with KBD, indicating that Zn2+ might play a key role in the pathogenesis of KBD, although the mechanism is unknown. The zinc-ZIP8-MTF1 axis in chondrocytes forms a catabolic cascade that promotes upregulation of the crucial effector matrix-degrading enzymes MMP3, MMP13, and ADAMTS5, thereby leading to osteoarthritis (OA) cartilage destruction. Zinc finger protein-related genes, the ZNT family, and the ZIP family of Zn2+ transporter genes have been found to be differentially expressed in KBD by high-throughput screening. Therefore, Zn2+ could play a key role in the pathogenesis of KBD.

Femoral epiphyseal cartilage matrix changes at predilection sites of equine osteochondrosis: Quantitative MRI, second-harmonic microscopy, and histological findings.

Osteochondrosis is an ischemic chondronecrosis of epiphyseal growth cartilage that results in focal failure of endochondral ossification and osteochondritis dissecans at specific sites in the epiphyses of humans and animals, including horses. The upstream events leading to the focal ischemia remain unknown. The epiphyseal growth cartilage matrix is composed of proteoglycan and collagen macromolecules and encases its vascular tree in canals. The matrix undergoes major dynamic changes in early life that could weaken it biomechanically and predispose it to focal trauma and vascular failure. Subregions in neonatal foal femoral epiphyses (n = 10 osteochondrosis predisposed; n = 6 control) were assessed for proteoglycan and collagen structure/content employing 3T quantitative MRI (3T qMRI: T1ρ and T2 maps). Site-matched validations were made with histology, immunohistochemistry, and second-harmonic microscopy. Growth cartilage T1ρ and T2 relaxation times were significantly increased (p < 0.002) within the proximal third of the trochlea, a site predisposed to osteochondrosis, when compared with other regions. However, this was observed in both control and osteochondrosis predisposed specimens. Microscopic evaluation of this region revealed an expansive area with low proteoglycan content and a hypertrophic-like appearance on second-harmonic microscopy. We speculate that this matrix structure and composition, though physiological, may weaken the epiphyseal growth cartilage biomechanically in focal regions and could enhance the risk of vascular failure with trauma leading to osteochondrosis. However, additional investigations are now required to confirm this. 3T qMRI will be useful for future non-invasive longitudinal studies to track the osteochondrosis disease trajectory in animals and humans. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1743-1752, 2016.

Identification of novel osteochondrosis--Associated genes.

During the early stages of articular osteochondrosis, cartilage is retained in subchondral bone, but the pathophysiology of this condition of growing humans and domestic animals is poorly understood. A subtractive hybridization study was undertaken to compare gene expression between the cartilage of early experimentally induced equine osteochondrosis lesions and control cartilage. Of the many putative differentially expressed genes identified, eight were confirmed by quantitative PCR analysis as differentially expressed, in addition to those already known to be associated with early lesions. Genes encoding vacuolar H(+)-ATPase V0 subunit d2 (ATP6V0D2), cathepsin K, integrin-binding sialoprotein, integrin αV, low density lipoprotein receptor-related protein 4, lumican, osteopontin, and thymosin ß4 (TMSB4) were expressed at higher levels in lesions than in control cartilage. These genes included 34 genes not previously identified in cartilage. Some genes identified as associated with early lesions are known chondrocyte hypertrophy-associated genes, and in transmission electron microscopy studies normal hypertrophic chondrocytes were observed in lesions. Differential expression of ATP6V0D2 and TMSB4 in the cartilage of early naturally occurring osteochondrosis lesions was confirmed by immunohistochemistry. These results identify novel osteochondrosis-associated genes and provide evidence that articular osteochondrosis does not necessarily result from failure of chondrocytes to undergo hypertrophy.

[INFLUENCE OF AUTOLOGOUS CHONDROCYTES TRANSPLANTATION ON THE INTERVERTEBRAL DISC STATE IN EXPERIMENTAL MODEL OF OSTEOCHONDROSIS].

The degenerative changes in the nucleus pulposus and fibrous ring of the intervertebral discs are the basis of spinal osteochondrosis. A large number of models, including biological, where some mechanisms of their development were worked out and studied, was used to study the morphogenesis and pathogenesis of degenerative spinal changes. The deserved place in the comparative experiments and especially the different methods of therapeutic effects on the tissues of the intervertebral discs in degenerative spinal changes is taken by the experimental methods. The biochemical changes of the intervertebral disc structures were analyzed under the administration of cultured autologous cell of nucleus pulposus suspension against a background of experimental model of rat osteochondrosis.

Effects of moderate amounts of barley in late pregnancy on growth, glucose metabolism and osteoarticular status of pre-weaning horses.

In stud management, broodmares are commonly fed concentrates in late pregnancy. This practice, however, was shown to correlate with an increased incidence of osteochondrosis in foals, which may be related to insulin sensitivity. We hypothesized that supplementation of the mare with barley in the last trimester of pregnancy alters the pre-weaning foal growth, glucose metabolism and osteoarticular status. Here, pregnant multiparous saddlebred mares were fed forage only (group F, n=13) or both forage and cracked barley (group B, n=12) from the 7th month of pregnancy until term, as calculated to cover nutritional needs of broodmares. Diets were given in two daily meals. All mares and foals returned to pasture after parturition. Post-natal growth, glucose metabolism and osteoarticular status were investigated in pre-weaning foals. B mares maintained an optimal body condition score (>3.5), whereas that of F mares decreased and remained low (<2.5) up to 3 months of lactation, with a significantly lower bodyweight (-7%) than B mares throughout the last 2 months of pregnancy. B mares had increased plasma glucose and insulin after the first meal and after the second meal to a lesser extent, which was not observed in F mares. B mares also had increased insulin secretion during an intravenous glucose tolerance test (IVGTT). Plasma NEFA and leptin were only temporarily affected by diet in mares during pregnancy or in early lactation. Neonatal B foals had increased serum osteocalcin and slightly increased glucose increments and clearance after glucose injection, but these effects had vanished at weaning. Body measurements, plasma IGF-1, T4, T3, NEFA and leptin concentrations, insulin secretion during IVGTT, as well as glucose metabolism rate during euglycemic hyperinsulinemic clamps after weaning, did not differ between groups. Radiographic examination of joints indicated increased osteochondrosis relative risk in B foals, but this was not significant. These data demonstrate that B or F maternal nutrition has very few effects on foal growth, endocrinology and glucose homeostasis until weaning, but may induce cartilage lesions.

Wnt/ß-catenin signaling of cartilage canal and osteochondral junction chondrocytes and full thickness cartilage in early equine osteochondrosis.

The objective of this study was to elucidate gene and protein expression of Wnt signaling molecules in chondrocytes of foals having early osteochondrosis (OC) versus normal controls. The hypothesis was that increased expression of components of Wnt signaling pathway in osteochondral junction (OCJ) and cartilage canal (CC) chondrocytes would be found in early OC when compared to controls. Paraffin-embedded osteochondral samples (7 OC, 8 normal) and cDNA from whole cartilage (7 OC, 10 normal) and chondrocytes surrounding cartilage canals and osteochondral junctions captured with laser capture microdissection (4 OC, 6 normal) were obtained from femoropatellar joints of 17 immature horses. Equine-specific Wnt signaling molecule mRNA expression levels were evaluated by two-step real-time qPCR. Spatial tissue protein expression of ß-catenin, Wnt-11, Wnt-4, and Dkk-1 was determined by immunohistochemistry. There was significantly decreased Wnt-11 and increased ß-catenin, Wnt-5b, Dkk-1, Lrp6, Wif-1, Axin1, and SC-PEP gene expression in early OC cartilage canal chondrocytes compared to controls. There was also significantly increased ß-catenin gene expression in early OC osteochondral junction chondrocytes compared to controls. Based on this study, abundant gene expression differences in OC chondrocytes surrounding cartilage canals suggest pathways associated with catabolism and inhibition of chondrocyte maturation are targeted in early OC pathogenesis.

Omics technologies provide new insights into the molecular physiopathology of equine osteochondrosis.

BACKGROUND: Osteochondrosis (OC(D)) is a juvenile osteo-articular disorder affecting several mammalian species. In horses, OC(D) is considered as a multifactorial disease and has been described as a focal disruption of endochondral ossification leading to the development of osteoarticular lesions. Nevertheless, OC(D) physiopathology is poorly understood. Affected horses may present joint swelling, stiffness and lameness. Thus, OC(D) is a major concern for the equine industry. Our study was designed as an integrative approach using omics technologies for the identification of constitutive defects in epiphyseal cartilage and/or subchondral bone associated with the development of primary lesions to further understand OC(D) pathology. This study compared samples from non-affected joints (hence lesion-free) from OC(D)-affected foals (n = 5, considered predisposed samples) with samples from OC-free foals (n = 5) considered as control samples. Consequently, results are not confounded by changes associated with the evolution of the lesion, but focus on altered constitutive molecular mechanisms. Comparative proteomics and micro computed tomography analyses were performed on predisposed and OC-free bone and cartilage samples. Metabolomics was also performed on synovial fluid from OC-free, OC(D)-affected and predisposed joints. RESULTS: Two lesion subtypes were identified: OCD (lesion with fragment) and OC (osteochondral defects). Modulated proteins were identified using omics technologies (2-DE proteomics) in cartilage and bone from affected foals compare to OC-free foals. These were associated with cellular processes including cell cycle, energy production, cell signaling and adhesion as well as tissue-specific processes such as chondrocyte maturation, extracellular matrix and mineral metabolism. Of these, five had already been identified in synovial fluid of OC-affected foals: ACTG1 (actin, gamma 1), albumin, haptoglobin, FBG (fibrinogen beta chain) and C4BPA (complement component 4 binding protein, alpha). CONCLUSION: This study suggests that OCD lesions may result from a cartilage defect whereas OC lesions may be triggered by both bone and cartilage defects, suggesting that different molecular mechanisms responsible for the equine osteochondrosis lesion subtypes and predisposition could be due to a defect in both bone and cartilage. This study will contribute to refining the definition of OC(D) lesions and may improve diagnosis and development of therapies for horses and other species, including humans.

Gene expression profiling of articular cartilage reveals functional pathways and networks of candidate genes for osteochondrosis in pigs.

Osteochondrosis (OC) is a joint disorder that frequently causes leg weakness in growing pigs, resulting in welfare problems and economic losses. We aimed to detect molecular pathways relevant to the emergence of the disease and to identify candidate genes for the liability to the disorder. Therefore, we compared microarray-based expression patterns of articular cartilage with (n=11) and without (n=11) histologically diagnosed OC lesions obtained from discordant sib-pairs. A total of 1,564 genes were found with different transcript abundance [differentially expressed (DE) genes] at q≤0.05. To further identify candidate genes, we integrated data from quantitative trait loci (QTL) and genome-wide association (GWA) studies with the expression analysis. We detected 317 DE genes within the QTL confidence intervals, of which 26 DE genes also overlapped GWA regions. Ingenuity Pathway Analysis suggests a pathogenic role of immune response, angiogenesis, and synthesis of extracellular matrix pathways for OC. These processes could facilitate the emergence of defects. But they may also promote the degradation of articular cartilage and the worsening of the disease. A functional network was derived that comprised genes with functional and positional clues of their role in bone and cartilage metabolisms and development, including extracellular matrix genes (e.g., LOX, OGN, and ASPN), angiogenesis genes (e.g., ANGPTL4 and PDGFA), and immune response genes (e.g., ICAM1, AZGP1, C1QB, C1QC, PDE4B, and CDA). The study identified molecular processes linked to OC and several genes with positional, genetic-statistical, and functional evidence for their role in the emergence of articular cartilage lesions and the liability to OC.

Evaluation of experimental impact injury for inducing post-traumatic osteoarthritis in the metacarpophalangeal joints of horses.

OBJECTIVE: To determine whether a single contusive impact injury to the palmar aspect of the metacarpus would progress to post-traumatic osteoarthritis or palmar osteochondral disease in horses. ANIMALS: 12 horses. PROCEDURES: In each horse, an impact injury was created on the palmar aspect of the medial metacarpal condyle of 1 randomly chosen limb with an impactor device under arthroscopic and fluoroscopic guidance. The opposite limb was sham operated as a control. A low to moderate amount of forced exercise was instituted, and horses were evaluated clinically via lameness examinations weekly for 5 months, then biweekly until endpoint, with synovial fluid analysis performed at 0, 1, 2, 3, 4, 6, 8, and 10 months and radiography at baseline and endpoint. Macroscopic examination, micro-CT, and sample collection for cartilage viability and sulfated glycosaminoglycan content, histologic evaluation, immunohistochemical analysis, and fluorochrome analysis were performed following euthanasia at 1 (3 horses), 4 (4), and 8 to 10 (5) months after surgery. RESULTS: There was variability in impact lesion location, depth, and area on macroscopic inspection, but on histologic evaluation, cartilage defects were less variable. Mean sulfated glycosaminoglycan concentration from cartilage at the impact site was significantly lower than that at a similar site in control limbs. Higher concentrations of cartilage oligomeric matrix protein were observed in synovial fluid from impact-injured joints. CONCLUSIONS AND CLINICAL RELEVANCE: The impact injury method caused mild focal osteoarthritic lesions in the metacarpophalangeal joint, but did not progress to palmar osteochondral disease at this site. Repeated injury is probably required for the development of palmar osteochondral disease.

Gene and protein expression of cartilage canal and osteochondral junction chondrocytes and full-thickness cartilage in early equine osteochondrosis.

The objective of this study was to investigate the expression of several regulatory factors associated with cartilage maturation in horses with early osteochondrosis (OC) compared to normal controls. The hypothesis was that expression levels of Indian hedgehog (Ihh), parathyroid hormone-related peptide (PTH-rP), vascular endothelial growth factor (VEGF), platelet-derived growth factor-A (PDGF-A), and matrix metalloproteinase-13 and -3 (MMP-13, -3) would be increased in OC. Articular cartilage and osteochondral samples were collected from the femoropatellar joints from seven OC and eight normal young (1-6 months) horses after euthanasia and snap frozen or suspended in 4% paraformaldehyde. Laser capture microdissection was used to capture cells surrounding cartilage canals and the osteochondral junction. Total RNA was isolated from whole cartilage and laser-captured cells. Equine-specific Ihh, PTH-rP, VEGF, PDGF-A, MMP-13, and MMP-3 mRNA expression levels were evaluated by real-time (RT)-PCR. Spatial tissue protein expression was determined by immunohistochemistry. In laser-captured samples, there was significantly increased MMP-13 and PDGF-A gene expression in chondrocytes adjacent to cartilage canals and increased PDGF-A gene expression in osteochondral junction chondrocytes of OC-affected foals. In full-thickness cartilage samples, there was significantly increased Ihh, MMP-3, and MMP-13 gene expression in OC samples, while PTH-rP protein expression was significantly higher along the osteochondral junction. The results suggest that pathways involving cartilage maturation and ossification are altered in early OC and may be associated with disease pathogenesis.

Gambling on putative biomarkers of osteoarthritis and osteochondrosis by equine synovial fluid proteomics.

Osteoarthritis (OA) and osteochondrosis (OC) are two of the main challenges in orthopedics, whose definitive diagnosis is usually based on radiographic/arthroscopic evidences. Their early diagnosis should allow preventive or timely therapeutic actions, which are generally precluded from the poor relationships occurring between symptomatologic and radiographic evidences. These limitations should be overcome by improving the knowledge on articular tissue metabolism and on molecular factors regulating its normal homeostasis, also identifying novel OA and OC biomarkers suitable for their earlier diagnoses, whenever clinical/pathological inflammatory scenarios between these joint diseases seem somewhat related. To identify proteins involved in their aetiology and progression, we undertook a differential proteomic analysis of equine synovial fluid (SF), which compared the protein pattern of OA or OC patients with that of healthy individuals. Deregulated proteins in OA and OC included components related to inflammatory state, coagulation pathways, oxidative stress and matrix damage, which were suggestive of pathological alterations in articular homeostasis, plasma-SF exchange, joint nutritional status and vessel permeability. Some proteins seemed commonly deregulated in both pathologies indicating that, regardless of the stimulus, common pathways are affected and/or the animal joint uses the same molecular mechanisms to restore its homeostasis. On the other hand, the increased number of deregulated proteins observed in OA with respect to OC, together with their nature, confirmed the high inflammatory character of this disease. Some deregulated proteins in OA found a verification by analyzing the SF of injured arthritic joints following autologous conditioned serum treatment, an emergent therapy that provides positive results for both human and equine OA. Being the horse involved in occupational/sporting activities and considered as an excellent animal model for human joint diseases, our data provide suggestive information for tentative biomedical extrapolations, allowing to overcome the limitations in joint size and workload that are typical of other small animal models.

Synovial fluid chondroitin sulphate indicates abnormal joint metabolism in asymptomatic osteochondritic horses.

REASONS FOR PERFORMING STUDY: Alternative methods to evaluate the joint condition in asymptomatic osteochondrosis dissecans (OCD) and other joint diseases may be useful. OBJECTIVES: To investigate possible changes in synovial fluid composition that may lead to joint conditions in asymptomatic OCD, in mature horses. METHODS: Animals aged >2 years, of different breeds, with OCD in the intermediate ridge of distal tibia, symptomatic or not, were studied. Synovial fluid samples (10 healthy; 11 asymptomatic OCD; 25 symptomatic OCD) were collected by arthroscopy from 29 horses. Glycosaminoglycans (GAGs) were analysed by a combination of agarose gel electrophoresis and enzymatic degradation with specific GAG lyases. The viscosity, white blood cell (WBC) count, protein concentration and hyaluronic acid (HA) molecular weight were also determined. RESULTS: The method used here to analyse synovial fluid GAGs is reliable, reproducible and specific. The main synovial fluid GAGs are HA and chondroitin sulphate (CS), 93% and 7% respectively in normal horses. In symptomatic OCD, the concentrations of both increased (expressed as GAG/urea ratios), but CS increased more. The CS increased also in asymptomatic OCD. An inflammatory reaction was suggested by the increased WBC counts in OCD. The molecular weight of the synovial fluid HA was reduced in OCD, explaining the lower viscosity observed. CONCLUSIONS: The increased CS in synovial fluid of OCD joints in mature horses suggests that the synovial fluid CS and the WBC count are good markers of the joint conditions, allowing the identification of pathological phase in joint diseases. POTENTIAL RELEVANCE: The analysis of synovial fluid GAGs shows that cartilage damage occurs even in asymptomatic OCD, implying that arthroscopic removal of osteochondral fragments should be performed even in asymptomatic OCD.

Biochemical evaluation of articular cartilage in patients with osteochondrosis dissecans by means of quantitative T2- and T2-mapping at 3T MRI: a feasibility study.

OBJECTIVE: To perform an in vivo evaluation comparing overlying articular cartilage in patients suffering from osteochondrosis dissecans (OCD) in the talocrural joint and healthy volunteers using quantitative T2 mapping at 3.0 T. METHOD AND MATERIALS: Ten patients with OCD of Grade II or lower and 9 healthy age matched volunteers were examined at a 3.0 T whole body MR scanner using a flexible multi-element coil. In all investigated persons MRI included proton-density (PD)-FSE and 3D GRE (TrueFisp) sequences for morphological diagnosis and location of anatomical site and quantitative T2 and T2 maps. Region of interest (ROI) analysis was performed for the cartilage layer above the OCD and for a morphologically healthy graded cartilage layer. Mean T2 and T2 values were then statistically analysed. RESULTS: The cartilage layer of healthy volunteers showed mean T2 and T2 values of 29.4 ms (SD 4.9) and 11.8 ms (SD 2.7), respectively. In patients with OCD of grade I and II lesions mean T2 values were 40.9 ms (SD 6.6), 48.7 ms (SD 11.2) and mean T2 values were 16.1 ms (SD 3.2), 16.2 ms (SD 4.8). Therefore statistically significantly higher mean T2 and T2 values were found in patients suffering from OCD compared to healthy volunteers. CONCLUSION: T2 and T2 mapping can help assess the microstructural composition of cartilage overlying osteochondral lesions.

Relationship between arthroscopic joint evaluation and the levels of Coll2-1, Coll2-1NO(2), and myeloperoxidase in the blood and synovial fluid of horses affected with osteochondrosis of the tarsocrural joint.

OBJECTIVE: To evaluate the levels of plasmatic and synovial Coll2-1, Coll2-1NO(2) and myeloperoxidase (MPO) in horses with osteochondral lesions of the tarsocrural joint and to investigate how these levels relate to arthroscopic findings of inflammation and degeneration. MATERIALS AND METHODS: Venous blood and synovial fluid samples were collected from 63 horses presented for arthroscopic removal of osteochondral fragments in the tarsocrural joint. Prior to removal of the osteochondral fragment, an exploration of the joint was performed and an inflammatory and degenerative score was determined. The blood and synovial levels of Coll2-1, Coll2-1NO(2) and MPO were also measured. The effects of the arthroscopic evaluation (inflammatory and degenerative classes) on the blood and synovial markers were evaluated using a linear model (GLM procedure), and correlations between biochemical markers in the blood and synovial fluid and the arthroscopic evaluation (inflammatory and degenerative classes) were established (Pearson's correlations). RESULTS: Significantly higher levels of Coll2-1 were detected in synovial fluid of higher degenerative classes. There was a significant correlation between the degenerative score and the synovial levels of Coll2-1 (r=0.27). According to the logistic regression model, there was a significant effect of the degenerative class on synovial levels of Coll2-1. CONCLUSIONS: Coll2-1 correlates well with the degenerative state of tarsocrural joints as evaluated by arthroscopy. This marker can therefore be classified as a burden-of-disease marker in the assessment of joint disease in horses.

Coll2-1, Coll2-1NO2 and myeloperoxidase concentrations in the synovial fluid of equine tarsocrural joints affected with osteochondrosis.

The measurement of biomarkers that reflect cartilage breakdown is a powerful tool for investigating joint damage caused by disease or injury. Particularly in cases of osteochondrosis, synovial concentrations of these biomarkers may reveal the presence of osteoarthritic changes. Coll2-1, Coll2-1 NO2 and myeloperoxidase have recently been introduced in equine osteoarticular research but comparison between the concentrations of these markers in OCD affected and healthy joints has not been made. Therefore, this study aimed at reporting the synovial concentrations of these biomarkers in joints affected with osteochondral fragments in the tarsocrural joint compared to unaffected joints. Myeloperoxidase and Coll2-1NO2 revealed to have similar levels between affected joints and controls. However, in contrast to previous studies using C2C the present study demonstrated that synovial levels of Coll2-1 were significantly elevated in tarsocrural joints affected with osteochondrosis. Thus, Coll2-1 may be an earlier marker of cartilage degeneration than other cartilage degradation markers that have been previously used in equine medicine.

Assessment of synovial fluid biomarkers in healthy foals and in foals with tarsocrural osteochondrosis.

Although alterations in biomarkers of cartilage turnover in synovial fluid (SF) have been demonstrated in horses with osteochondrosis (OC), there have been few investigations of such alterations in animals <1 year old. In this study tarsocrural SF samples from foals aged 18, 22 and 52 weeks of age were assessed for: (1) 'turnover' biomarkers of type II collagen (CPII and C2C) and proteoglycan (CS846 and glycosaminoglycans [GAG]); (2) matrix metalloproteinase (MMP) activity; (3) insulin-like growth factor (IGF)-1; (4) transforming growth factor (TGF)-ß1; (5) prostaglandin (PG) E(2); and (6) leukotriene B(4). Using a linear mixed model, the concentration of biomarkers was compared between animals that developed or did not develop radiographic evidence of OC at 24 or 48 weeks of age. The CPII:C2C ratio tended to be higher in OC-affected joints compared to controls at all ages, and this difference was statistically significant at 22 weeks of age. The concentrations of CS846 and IGF-1, and the CS846:GAG ratio were reduced in OC-affected joints relative to controls at 18 weeks of age only. At 52 weeks of age, the PGE(2) concentration was lower in joints with OC. Overall, there appears to be a consistent anabolic shift in type II collagen turnover in juvenile joints affected by OC. Aberrant proteoglycan turnover is not a hallmark of the late repair of this lesion but reduced concentrations of IGF-1 in SF may be associated with early-stage lesions.