Functional adaptation through changes in regional biochemical characteristics during maturation of equine superficial digital flexor tendons.

Objective: To quantify and compare biochemical characteristics of the extracellular matrix (ECM) of specimens harvested from tensional and compressive regions of the superficial digital flexor tendon (SDFT) of horses in age classes that include neonates to mature horses.

Sample Population: Tendon specimens were collected on postmortem examination from 40 juvenile horses (0, 5, 12, and 36 months old) without macroscopically visible signs of tendonitis.

Procedure: Central core specimens of the SDFT were obtained with a 4-mm-diameter biopsy punch from 2 loaded sites, the central part of the mid-metacarpal region and the central part of the mid-sesamoid region.

Biochemical analysis of the articular cartilage and subchondral and trabecular bone of the metacarpophalangeal joint of horses with early osteoarthritis.

Objective: To assess whether site-related changes in biochemical composition are present in the cartilage and subchondral and trabecular bone of the metacarpophalangeal joint of horses with early osteoarthritis.

Sample Population: Right metacarpophalangeal joints from 59 mature warmblood horses.

Procedure: Biochemical data (cross-link, amino acid, DNA, and ash contents; denatured collagen and glycosaminoglycan [GAG] concentrations; bone mineral density; and mineral composition) were obtained from 2 differently loaded sites of phalanx I cartilage and subchondral and trabecular bone samples; data were compared with previously published values from nonosteoarthritic equine joints.

Extracellular matrix composition of the equine superficial digital flexor tendon: relationship with age and anatomical site.

The objectives of the present study were to test the hypotheses that: (1) the composition of the extracellular matrix of the equine superficial digital flexor tendon (SDFT) shows great functional similarities with articular cartilage, i.e. that significant differences exist in biochemical composition of differently loaded areas (which in the case of tendons may be more apparent as tendon shows more obvious differences than cartilage); and (2) that, as in articular cartilage, no substantial alterations in biochemical composition take place during ageing once adulthood has been attained.

Study of cartilage and bone layers of the bearing surface of the equine metacarpophalangeal joint relative to different timescales of maturation.

Reasons For Performing Study: A detailed and comprehensive insight into the normal maturation process of the different tissues that make up functional units of the locomotor system such as joints is necessary to understand the influence of early training on musculoskeletal tissues.

Objectives: To study simultaneously the maturation process in the entire composite structure that makes up the bearing surface of a joint (cartilage, subchondral and trabecular bone) in terms of biochemical changes in the tissues of juvenile horses at 2 differently loaded sites of the metacarpophalangeal joint, compared to a group of mature horses.

Hypothesis: In all the structures described above developmental changes may follow a different timescale.

An integral biochemical analysis of the main constituents of articular cartilage, subchondral and trabecular bone.

Objective: In articular joints, the forces generated by locomotion are absorbed by the whole of cartilage, subchondral bone and underlying trabecular bone. The objective of this study is to test the hypothesis that regional differences in joint loading are related to clear and interrelated differences in the composition of the extracellular matrix (ECM) of all three weight-bearing constituents.

Method: Cartilage, subchondral- and trabecular bone samples from two differently loaded sites (site 1, dorsal joint margin; site 2, central area) of the proximal articular surface of 30 macroscopically normal equine first phalanxes were collected.

MMP profile in paired serum and synovial fluid samples of patients with rheumatoid arthritis.

Objective: To analyse matrix metalloproteinases (MMPs) and tissue inhibitor-1 of MMPs (TIMP-1) levels in the systemic circulation and synovial fluid (SF) of patients with RA and to compare these levels with inflammatory and collagen degradation markers.

Methods: ProMMP-1, -2, -3, -8, -9, TIMP-1, levels of MMP/alpha(2)-macroglobulin complexes, and collagen degradation products were measured by sandwich ELISA, activity assays, and HPLC in paired SF and serum samples from 15 patients with RA and 13 with OA.

Results: MMPs were higher in SF of patients with RA than in OA or controls.

The influence of repeated arthrocentesis and exercise on matrix metalloproteinase and tumour necrosis factor alpha activities in normal equine joints.

Reasons For Performing Study: Matrix metalloproteinases (MMPs) and tumour necrosis factor alpha (TNF-alpha) may be useful as biomarkers of joint disease or inflammation. However, activity of both MMPs and TNF-alpha in synovial fluid (SF) may be influenced by nonpathological factors such as arthrocentesis or exercise.

Objective: To investigate the influence of repeated arthrocentesis and exercise on MMP and TNF-alpha activities in SF from normal equine joints.

Assessment of the effects of age and joint disease on hydroxyproline and glycosaminoglycan concentrations in synovial fluid from the metacarpophalangeal joint of horses.

Objective: To assess the effects of age and joint disease on hydroxyproline and glycosaminoglycan (GAG) concentrations in synovial fluid from the metacarpophalangeal joint of horses and evaluate the association of those concentrations with severity of osteoarthritis and general matrix metalloproteinase (MMP) activity.

Sample Population: Synovial fluid was collected from the metacarpophalangeal joints of foals at birth (n = 10), 5-month-old foals (10), 11-month-old foals (5), and adult horses (73).

Procedure: Hydroxyproline and GAG concentrations were determined in synovial fluid samples.

Collagenase-1 (MMP-1) activity in equine synovial fluid: influence of age, joint pathology, exercise and repeated arthrocentesis.

Reasons For Performing Study: Matrix metalloproteinases (MMPs) are considered candidate biomarkers for both physiological and pathological tissue remodelling because of their key role in articular cartilage homeostasis. As disruption of the collagenous architecture is thought to be pivotal in chronic degenerative diseases such as osteoarthritis (OA), the collagenases form an interesting subset of the MMPs. The significance of any biomarker in synovial fluid (SF) can be assessed properly only when fluctuations in patterns induced by physiological processes such as development and growth, and by external influences and interventions such as exercise and repeated arthrocentesis, are known and taken into account.

Advanced glycation end product ligands for the receptor for advanced glycation end products: biochemical characterization and formation kinetics.

Advanced glycation end products (AGEs) accumulate with age and at an accelerated rate in diabetes. AGEs bind cell-surface receptors including the receptor for advanced glycation end products (RAGE). The dependence of RAGE binding on specific biochemical characteristics of AGEs is currently unknown.