Profiling the secretion of soluble mediators by end stage osteoarthritis synovial tissue explants reveals a reduced responsiveness to an inflammatory trigger.

Objective: Evidence is accumulating that synovial tissue plays an active role in osteoarthritis (OA), however, exact understanding of its contribution is lacking. In order to further elucidate its role in the OA process, we aimed to identify the secretion pattern of soluble mediators by synovial tissue and to assess its ability to initiate cartilage degeneration.

Methods: Synovial tissue explants (STEs) obtained from donors without history of OA (n = 8) or from end stage OA patients (n = 16) were cultured alone or together with bovine cartilage explants in the absence or presence of IL-1α.

Longevity of elastin in human intervertebral disc as probed by the racemization of aspartic acid.

Background: Aging and degeneration of human intervertebral disc (IVD) are associated with biochemical changes, including racemization and glycation. These changes can only be counteracted by protein turnover. Little is known about the longevity of IVD elastin in health or disease.

Integration of efficacy, pharmacokinetic and safety assessment of interleukin-1 receptor antagonist in a preclinical model of arthritis.

Pharmacokinetic properties and safety profile of a drug are likely influenced by the disease state of a patient. In this study, we investigated the influence of arthritic processes on pharmacokinetics and immunotoxicity of interleukin-1 receptor antagonist (Anakinra) in the rat adjuvant arthritis model. Anakinra dose-dependently suppressed joint inflammation and degradation as demonstrated by reduced clinical arthritis score, paw thickness, synovial infiltration and bone degradation.

Does loading influence the severity of cartilage degeneration in the canine Groove-model of OA?

Many animal models are used to study osteoarthritis (OA). In these models the role of joint loading in the development of OA is not fully understood. We studied the effect of loading on the development of OA in the canine Groove-model.

Profiling of endogenous peptides in human synovial fluid by NanoLC-MS: method validation and peptide identification.

Synovial fluid potentially contains markers for early diagnosis and disease progression in degenerative joint diseases such as osteoarthritis. Here, a method is described for profiling endogenous peptides in human synovial fluid, using ultrafiltration, solid-phase extraction, nanoscale liquid chromatography, and high-resolution mass spectrometry. Synovial fluid is characterized by its high viscosity, caused by the presence of the lubricant hyaluronic acid.

Achilles tendinosis: changes in biochemical composition and collagen turnover rate.

Background: Understanding biochemical and structural changes of the extracellular matrix in Achilles tendinosis might be important for developing mechanism-based therapies.

Hypothesis: In Achilles tendinosis, changes occur in biochemical composition and collagen turnover rate.

Study Design: Descriptive laboratory study.

Corticosteroids reduce the tensile strength of isolated collagen fascicles.

Background: Overuse tendon injuries are frequent. Corticosteroid injections are commonly used as treatment, although their direct effects on the material properties of the tendon are poorly understood.

Purpose: To examine the influence of corticosteroids on the tensile strength of isolated collagen fascicles.

Accumulation of advanced glycation end products as a molecular mechanism for aging as a risk factor in osteoarthritis.

Objective: Osteoarthritis (OA) is one of the most prevalent and disabling chronic conditions affecting the elderly. Its etiology is largely unknown, but age is the most prominent risk factor. The current study was designed to test whether accumulation of advanced glycation end products (AGEs), which are known to adversely affect cartilage turnover and mechanical properties, provides a molecular mechanism by which aging contributes to the development of OA.

Matrix metalloproteinase activities and their relationship with collagen remodelling in tendon pathology.

Our aim was to correlate the activity of matrix metalloproteinases (MMPs) with denaturation and the turnover of collagen in normal and pathological human tendons. MMPs were extracted from ruptured supraspinatus tendons (n=10), macroscopically normal ("control") supraspinatus tendons (n=29) and normal short head of biceps brachii tendons (n=24). Enzyme activity was measured using fluorogenic substrates selective for MMP-1, MMP-3 and enzymes with gelatinolytic activity (MMP-2, MMP-9 and MMP-13).