Human xylosyltransferases--mediators of arthrofibrosis? New pathomechanistic insights into arthrofibrotic remodeling...

Area of Science:

• Biomedical Engineering
• Orthopedics
• Rheumatology

Background:

• Total knee replacement (TKR) can lead to arthrofibrosis in 10% of patients, with unclear underlying mechanisms.
• Arthrofibrosis involves excessive fibrotic remodeling of joint tissues.
• Xylosyltransferases (XT) are key enzymes in glycosaminoglycan biosynthesis, potentially mediating fibrosis.

Purpose of the Study:

• To investigate the role of xylosyltransferases (XT) in arthrofibrosis following TKR.
• To assess the potential of serum XT activity as a diagnostic marker for arthrofibrosis.
• To explore therapeutic targets for preventing arthrofibrotic remodeling.

Main Methods:

• Synovial fibroblasts (SF) were isolated from arthrofibrotic and control synovial biopsies.
• Assessed fibroblast-myofibroblast transition via α-smooth muscle actin (α-SMA) expression.
• Measured XT activity, α-SMA protein, and mRNA expression of XT-I, COL3A1, and ACTA2.
• Compared serum XT-I, galectin-3, and GDF-15 levels between patients with and without arthrofibrosis.

Main Results:

• Arthrofibrotic fibroblasts showed higher basal α-SMA expression, indicating increased fibroblast-myofibroblast transition.
• Transforming growth factor-β1 (TGF-β1) stimulation enhanced fibrotic remodeling markers (XT activity, α-SMA, XT-I, COL3A1, ACTA2 mRNA) in arthrofibrotic fibroblasts.
• No significant differences in serum XT-I, galectin-3, or GDF-15 levels were found between arthrofibrosis patients and controls.

Conclusions:

• XT-I is a key cellular mediator of arthrofibrosis and a potential therapeutic target.
• The blood-synovial barrier prevents arthrofibrotic molecular changes from being detected in serum.
• Future monitoring or prevention strategies for arthrofibrosis should focus on local, not systemic, parameters.