Effects of Autologous Conditioned Serum on inflammatory-equine cartilage

Autologous conditioned serum (ACS) and autologous protein solution (APS) are
newer therapeutic options for osteoarthritis (OA). Co-culture of cartilage and synovium
stimulated with IL-1b produces a similar physiologic response to tissues from
naturally-ocurring OA. The study objective was to investigate the effects of ACS, APS,
and triamcinolone (TA) on inflammatory and catabolic gene expression of inflamed
joint tissues in co-culture. Blood was collected and processed for ACS and APS from
six horses. Cartilage and synovial explants were harvested from the stifle, placed in
co-culture, and treated as: (1) unstimulated control (2) stimulated control (3) ACS at 25%
v/v (4) ACS at 50% v/v (5) APS at 25% v/v (6) APS at 50% v/v, (7) TA (10−6 M). Treatment
groups 2–7 were stimulated with IL-1b (10 ng/ml). Cultures were maintained for 96 hours,
and then both media and explants were harvested for measurement of gene expression
and protein. IL-1b stimulation significantly increased IL-1b (p = 0.029), IL-8 (p = 0.011)
and MMP-3 (p = 0.043) expression in synovium and IL-1b (p = 0.003) and TNF-a
(p = 0.001) expression in cartilage. Treatment with 50%ACS and APS v/v downregulated
IL-1b expression in cartilage more than TA treatment (p = 0.001 and p = 0.0004) and
APS downregulated MMP-1 expression in synovial membrane (p = 0.025). Treatment
with ACS and APS caused a trend in upregulation of IL-10 expression in synovium and
type II collagen and aggrecan expression in cartilage. PGE2 media concentrations were
significantly reduced following treatment with APS (13.7-fold decrease, p = 0.0001)
and ACS (4.13-fold decrease, p = 0.024); while TA did not reduce PGE2 significantly
(2.3-fold decreased p = 0.406). As disease-modifying therapies, ACS and APS modified
the cellular response from synovial membrane and articular cartilage. ACS and APS may
offer an improved strategy to improve clinical signs of horses with naturally occurring OA,
compared to TA treatment.