What is the pathophysiology behind the radiographic features seen in Axial Spondyloarthritis?
Unknown. Experimental data from mouse models support that inflammation and bone remodeling are two independent processes. The model shows:
• Bone morphogenic proteins (BMP) and the WNT family of proteins may contribute to the development of calcification at sites of entheses and the sacroiliac joints. TNFα has a ying-yang effect on this process. It stimulates BMP production but downregulates WNT signaling through upregulation of DKK1.
• The presence of enthesis-resident T cells (CD3+CD4-CD8-IL-23R+) that respond to IL-23 with resultant release of IL-17 (causing local inflammation) and IL-22 (inducing osteoblast-mediated bone formation).