Bone formation in axial spondyloarthritis

Area of Science:

• Rheumatology and Immunology
• Skeletal Biology
• Therapeutic Development

Background:

• Tumor necrosis factor (TNF) inhibitors have improved spondyloarthritis treatment, shifting focus to preventing structural damage.
• Structural damage, including new bone formation leading to ankylosis, causes functional loss in spondyloarthritis.
• Understanding the interplay between inflammation and new bone formation is crucial for developing effective long-term strategies.

Purpose of the Study:

• To review current understanding of structural damage in spondyloarthritis.
• To explore the link between inflammation and new bone formation.
• To identify potential therapeutic targets and windows of opportunity for inhibiting structural progression.

Main Methods:

• Analysis of existing human and animal study data.
• Review of recent discoveries in spondyloarthritis pathophysiology, including T cell populations and auto-antibodies.
• Evaluation of long-term data from tumor necrosis factor (TNF) inhibitor trials.

Main Results:

• Evidence strongly links inflammation and new bone formation in spondyloarthritis, though the sequence and triggers require further elucidation.
• Growth factor signaling pathways and specific T cell populations (IL23 receptor) are implicated.
• Auto-antibodies against noggin and sclerostin offer new insights.
• TNF inhibitors may offer a window to inhibit structural disease progression.

Conclusions:

• Further research and critical analysis of existing data are needed to understand spondyloarthritis pathophysiology and structural damage.
• Novel disease definitions, especially for non-radiographic axial spondyloarthritis, are vital for advancing knowledge.
• Targeting specific pathways and understanding disease triggers are key to preventing long-term disability.