The Effect of Autologous Protein Solution on the Inflammatory Cascade in Stimulated Equine Chondrocytes

Abstract

Cartilage injury occurs commonly in equine athletes, often precipitating posttraumatic osteoarthritis (PTOA). Orthobiologics such as autologous conditioned serum (ACS) and autologous protein solution (APS) may be useful in decreasing posttraumatic inflammation, thereby preventing PTOA. The objective of this study was to quantify cytokine concentrations in ACS and APS and evaluate the protective effects of ACS and APS on inflamed chondrocytes cultured in vitro. We hypothesized that the combination of platelet-derived growth factors (PDGF) and anti-inflammatory cytokines present in APS would be superior in decreasing the inflammatory and catabolic cascade in inflamed chondrocytes when compared to ACS in which platelets are excluded from the preparation. Chondrocytes were isolated from the cartilage of femoral trochlear ridges of 6 horses and cultured in 12-well transwell plates. Treatment groups included: (1) control, (2) APS (Pro-Stride; Owl Manor), and (3) ACS (IRAP II; Arthrex). Each group was unstimulated or stimulated with IL-1β and TNF-α for 48 h. The concentration of IL-1β, IL-6, TNF-α, MMP-3, MMP-13, and IL-10 was quantified using a fluorescent bead-based multiplex assay. IL-1Ra concentration was quantified using ELISA. APS and ACS both had significantly increased concentrations of IL-1Ra without a concurrent increase in IL-1β concentration. After 48 h of culture, media from chondrocytes treated with APS contained significantly increased concentrations of IL-1Ra and IL-10. APS-treated cultures had increased concentrations of IL-6. Overall, APS effectively concentrated IL-1Ra without an incubation period and media from APS-treated chondrocytes had increased concentrations of chondroprotective (IL-1Ra and IL-10) and modulatory (IL-6) cytokines, which may be beneficial in the treatment of inflammatory conditions such as PTOA.

Effects of Autologous Conditioned Serum, Autologous Protein Solution, and Triamcinolone on Inflammatory and Catabolic Gene Expression in Equine Cartilage and Synovial Explants Treated With IL-1β in Co-culture

“…The results of our study showed a smaller increase in WBCs (12.1 vs. 4.9-fold increase) and a greater increase in PLTs (1.6 vs. 3.5-fold increase) compared to what has been reported by Bertone et al, most likely due to individual variations in physiologic status. In our study, ACS produced a significantly higher concentration of sTNF-R1 (p = 0.009) and TGF-β (p = 0.024), compared to APS, while another publication found that APS produced a higher concentration of TGF-β compared to ACS (11). Significant differences in cytokine concentration using different commercial kits under different physiologic conditions from the same horse has been reported with ACS (8,10), which could explain differences between studies.…”

“…In horses and dogs, APS has improved pain scores and reduced lameness up to 1 year after treatment (9,32). In vitro, limited anti-inflammatory effects have been observed following treatment of articular cells and/or tissues with APS (11,33,34).…”

A Survey of Clinical Usage of Non-steroidal Intra-Articular Therapeutics by Equine Practitioners

“…Recently, non-steroidal intraarticular therapies (NSIATs), such as biological and synthetic products, have become more popular. NSIATs have been shown to possess limited disease-modifying properties, such as slowing down disease progression and enhancing the quality of repair tissue (5)(6)(7)(8)(9)(10)(11).…”

Autologous cell-free serum preparations in the management of knee osteoarthritis: what is the current clinical evidence?

“…Hix et al [20] reported the average concentration of IL-1Ra in APS to be 63,740 pg/ml whereas Woodell-May et al [46] noted it to be 30,853 pg/ml. The wide variation in the IL-1Ra levels of ACS and APS reported by the investigators may be due a combination of the production kit and the 24-h incubation period used during the preparation of ACS [47]. Various anabolic factors, including epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), IGF, TGF-β and the anti-inflammatory cytokines soluble tumor necrosis factor receptor type II (sTNF-RII), IL-4 and IL-10, have been noted in APS [46].…”

“…The aforementioned growth factors, which include TGF-β, PDGF, VEGF and IGF, have been shown to stimulate chondrocyte proliferation and augment articular cartilage metabolism [44,52]. Whilst it is perceived that both ACS and APS potentially mitigate the inflammatory cascade, the detailed pathways or mechanisms through which they perform these actions have not been fully described [40,45,47,53].…”