Counts of hyaluronic acid-containing extracellular vesicles decrease in naturally occurring equine osteoarthritis.

Area of Science:

• Veterinary Medicine
• Biochemistry
• Cell Biology

Background:

• Osteoarthritis (OA) is a degenerative joint disease causing pain and limited mobility.
• Extracellular vesicles (EVs) in synovial fluid play roles in OA pathogenesis.
• Hyaluronic acid (HA) is a key molecule in joint lubrication, transported by EVs.

Purpose of the Study:

• To characterize synovial fluid (SF) EVs and their HA content in horses with naturally occurring OA.
• To investigate the potential of HA-containing EVs (HA-EVs) as biomarkers for equine OA.

Main Methods:

• Collected SF from control and OA metacarpophalangeal joints in horses.
• Quantified HA concentrations using ELISA and size-exclusion chromatography.
• Utilized nanoparticle tracking analysis (NTA) for small EVs and confocal laser scanning microscopy (CLSM) for larger EVs.

Main Results:

• Small EV counts and size distribution were not significantly affected by OA.
• A decrease in the number and proportion of larger HA-EVs was observed in OA SF.
• Lower total HA concentrations were found in OA joints.
• An inverse association was noted between OA grade and HA-EV counts and percentages.

Conclusions:

• Synovial fluid HA-EVs show potential as a biomarker for naturally occurring equine OA.
• Further research is needed to explore the role of HA-EVs in OA pathogenesis and their therapeutic potential.