K.A. Kimmerling

Articular Ankle Fracture Results in Increased Synovitis, Synovial Macrophage Infiltration, and Synovial Fluid Concentrations of Inflammatory Cytokines and Chemokines

The inflammatory response following an articular fracture is thought to play a role in the development of posttraumatic arthritis (PTA) but has not been well characterized. The objective of this study was to characterize the acute inflammatory response, both locally and systemically, in joint synovium, synovial fluid (SF), and serum following articular fracture of the ankle. We hypothesized that intraarticular fracture would alter the synovial environment and lead to increased local and systemic inflammation.

Serum and synovial fluid lipidomic profiles predict obesity-associated osteoarthritis, synovitis, and wound repair

High-fat diet-induced obesity is a major risk factor for osteoarthritis (OA) and diminished wound healing. The objective of this study was to determine the associations among serum and synovial fluid lipid levels with OA, synovitis, adipokine levels, and wound healing in a pre-clinical obese mouse model of OA. Male C57BL/6 J mice were fed either a low-fat (10% kcal) or one of three high-fat (HF, 60% kcal) diets rich in saturated fatty acids (SFAs), ω-6 or ω-3 polyunsaturated FAs (PUFAs). OA was induced by destabilization of the medial meniscus. Mice also received an ear punch for evaluating wound healing. Serum and synovial fluid were collected for lipidomic and adipokine analyses. We demonstrated that the serum levels of ω-3 PUFAs were negatively correlated with OA and wound size, but positively correlated with adiponectin levels. In contrast, most ω-6 PUFAs exhibited positive correlations with OA, impaired healing, and inflammatory adipokines. Interestingly, levels of pentadecylic acid (C15:0, an odd-chain SFA) and palmitoleic acid were inversely correlated with joint degradation. This study extends our understanding of the links of FAs with OA, synovitis and wound healing, and reports newly identified serum and synovial fluid FAs as predictive biomarkers of OA in obesity.

Conditional Macrophage Depletion Increases Inflammation and Does Not Inhibit the Development of Osteoarthritis in Obese Macrophage Fas‐Induced Apoptosis–Transgenic Mice

To investigate whether short‐term, systemic depletion of macrophages can mitigate osteoarthritis (OA) following injury in the setting of obesity.

Survey of Animal Models in Post-Traumatic Arthritis: Choosing the Right Model to Answer the Right Question

The selection of a model to study post-traumatic arthritis is a challenging and potentially confusing decision. This chapter was added specifically to address questions investigators may have when considering moving their work into an animal model. It is not possible to cover every possible species of animal that could be used. Therefore, this chapter provides a comprehensive review of the various aspects of arthritis after joint injury that can be studied in three commonly used species. This work provides an overview of what assays, information, and data can be available to the investigators. It is important that investigators are certain they will be able to collect data to address their research question before the investigation begins.

Anterior Cruciate Transection/Disruption Models of Post-Traumatic Arthritis

The anterior cruciate ligament (ACL) plays a critical role in knee stability, and clinically, ACL tears greatly increase the risk for post-traumatic arthritis. In this regard, animal models of ACL transection or disruption have been developed using a variety of species, including dogs, sheep, cats, rabbits, guinea pigs, rats, and mice. These models have used different techniques for disrupting the function of the ACL, including open surgery, stab incision, arthroscopic transection, and noninvasive joint loading. The outcome measures of these studies have included characterization of the ensuing effects on the articular cartilage, synovium, genetic markers, and biomarkers, and have provided a means of testing different therapeutic interventions. In summary, animal models of ACL injury provide repeatable and relatively straightforward means of reproducing many of the characteristics of human PTA, on a more rapid time frame. Here we review the animal models used for studying post-traumatic arthritis, and discuss the potential advantages and disadvantages of different animals and approaches.