The enthesis in psoriatic arthritis

Area of Science:

• Immunology
• Rheumatology
• Biomedical Engineering

Background:

• Enthesitis is increasingly recognized as a primary pathology in psoriatic arthritis and spondyloarthritis.
• Animal models highlight the IL-23/IL-17 axis and TNF-dependent pathways, alongside joint biomechanics at entheses, as crucial factors.
• Therapeutic strategies targeting these pathways show efficacy in human studies.

Purpose of the Study:

• To explore the underlying immunological basis of enthesitis in psoriatic arthritis and spondyloarthritis.
• To investigate the role of biomechanics in entheseal pathology.
• To identify gaps in understanding human entheseal immunology for improved therapeutic development.

Main Methods:

• Review of animal models elucidating IL-23/IL-17 axis and TNF-dependent inflammation.
• Analysis of empirical data on the effectiveness of anti-IL23/17 and anti-TNF therapies in human enthesitis.
• Discussion of biomechanical factors influencing enthesitis.
• Identification of challenges in obtaining human entheseal tissue for histological analysis.

Main Results:

• Animal models provide strong support for enthesitis as a primary lesion driven by specific inflammatory axes and biomechanical stress.
• Clinical data confirm the efficacy of IL-23/17 and TNF-targeting therapies for entheseal pathology.
• The biological mechanisms of other therapies, like PDE4 inhibitors, remain unclear due to limited human entheseal tissue data.

Conclusions:

• Enthesitis is a central feature in psoriatic arthritis and spondyloarthritis, with significant contributions from biomechanics and specific inflammatory pathways.
• While targeted therapies are effective, a deeper understanding of human entheseal immunology is essential for advancing treatment strategies.
• Further research into human entheseal immunology is critical for developing more refined and effective therapies for these conditions.