Background/Purpose:

Psoriatic arthritis is a chronic joint disease clinically associated with psoriasis. Some patients also have signs of inflammatory bowel disease. Enthesitis, inflammation at the attachment sites of ligaments and tendons into the bone, is put forward as key mechanism leading to the clinical manifestations of psoriatic arthritis. One of the leading hypothesis for initiation of disease is that biomechanical stress, together with other initiating factors, plays a role in altering the properties of the anatomic region, thus leading to the development of the disease and its amplification in other compartments of the synovio-entheseal complex.

In this study, we aim to understand early events leading to the onset of psoriatic arthritis, in the presence of distant inflammation in the skin and the intestine.

Methods:

Eight-week-old male C57/Bl6 mice were treated with imiquimod cream (IMQ) on a shaved area of the back skin or with dextran sodium sulphate (DSS) dissolved in the drinking water to induce psoriasis-like skin or inflammatory bowel disease-like gut inflammation. Control mice were left untreated. Afterwards, half of the mice were subject to a forced treadmill running protocol to increase biomechanical stress. Control mice with or without IMQ or DSS treatment did not run. Severity of cutaneous or intestinal inflammation was assessed clinically and by histology; knees and paws were evaluated with microCT, histology and immunohistochemistry.

Results:

The clinical and histopathologic assessment of skin and intestine sections confirmed that we have successfully induced the two models of inflammation in immune-competent tissues. In both models, signs of systemic inflammation were also present and a significant loss of trabecular bone was indicated by microCT analyses. Signs of synovitis have been detected both for IMQ and DSS protocol, but increased inflammation of the entheses was detected only with the IMQ model. The running protocol appear to affect the joints at the cartilage and the entheseal level.

Conclusion:

The presence of cutaneous or intestinal inflammation and the associated bone loss influence the impact of biomechanical stress at the joint level.

« Back to 2018 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/inflammation-at-distant-immunocompetent-sites-combined-with-a-protocol-of-forced-exercise-induces-mild-joint-inflammation/