Inflammatory mediators are potential biomarkers for extracorporeal shockwave therapy in horses

Abstract

Summary Background Extracorporeal shockwave therapy (ESWT) can potentially mask painful injuries in equine athletes. Tests to detect whether a horse has received ESWT prior to competition are needed. Extracorporeal shockwave therapy is known to affect inflammatory mediators in other species, and if these mediators are altered in the horse, these could serve as biomarkers of ESWT. Objectives To test the hypothesis that a single application of ESWT will alter the circulating protein concentrations of 10 inflammatory mediators in horse plasma. Study design Prospective repeated measures experimental study. Methods Eleven healthy horses were administered a single dose of ESWT on the dorsal surface of proximal MCIII. Blood samples were collected at −168, −144, −120, −96, −72, −70, −68, −66, −48, −24, −6, −4, −2, 0 h before and 2, 4, 6, 24, 48, 72, 96, 168, 336 and 504 h after ESWT. Plasma concentrations of interleukin 1 beta (IL‐1β), IL‐1 receptor antagonist (IL‐1RA), IL‐2, IL‐4, IL‐6, IL‐10, IL‐15, interferon gamma (IFN‐γ), soluble toll‐like receptor 2 (sTLR2) and tumour necrosis factor alpha (TNF‐α) were measured to assess the effects of ESWT on these mediators. Results Baseline concentrations of inflammatory mediators did not change substantially during the week prior to ESWT. Plasma concentrations of five inflammatory factors changed following ESWT. IL‐1β and IL‐6 were significantly down‐regulated (P<0.01), while TNF‐α, IL‐1RA and TLR2 were significantly up‐regulated (P<0.01). The remaining cytokines were not significantly affected by ESWT. Main limitations This study was performed in a small number of sedentary, healthy pasture‐kept horses using a single dose of ESWT applied to a single location. Additional studies are necessary to determine the effect of ESWT on inflammatory mediators in athletic horses undergoing treatment for musculoskeletal injuries. Conclusions Plasma concentrations of TNF‐α, IL‐1β, IL‐1RA, IL‐6 and TLR2 were significantly affected by ESWT, and deserve further investigation as possible biomarkers of ESWT.

Gene transcripts expressed in equine white blood cells are potential biomarkers of extracorporeal shock wave therapy

“…IL-1Ra protein was also increased in the corresponding plasma samples. 16 Importantly, this study demonstrates an increase in the gene transcript for IL1β in circulating WBC, while the study of the corresponding plasma samples from the same administration study found a decrease in IL1β protein expression. 16 This is not an unusual finding; studies of gene transcription and protein expression for the same target often find differing effects of a treatment or condition on the gene transcript and protein expression levels.…”

“…16 Importantly, this study demonstrates an increase in the gene transcript for IL1β in circulating WBC, while the study of the corresponding plasma samples from the same administration study found a decrease in IL1β protein expression. 16 This is not an unusual finding; studies of gene transcription and protein expression for the same target often find differing effects of a treatment or condition on the gene transcript and protein expression levels. The regulation of protein translation from the gene transcripts is a complex process with a number of regulatory steps, underscoring the importance of assessing each type of potential biomarker directly.…”

“…A single dose of ESWT applied to the distal limb of a horse has been demonstrated to alter circulating levels of pro-and anti-inflammatory proteins. 16 IL-1b and IL-6 were significantly down-regulated, while TNF-a, IL-1RA, and TLR2 were significantly up-regulated. Changes in gene expression precede changes in protein production; thus, gene transcripts may also serve as biomarkers of ESWT.…”

“…Changes in biomarkers have been proposed as a method for detecting ESWT; however, there is limited information on the biological effects of ESWT. A single dose of ESWT applied to the distal limb of a horse has been demonstrated to alter circulating levels of pro‐ and anti‐inflammatory proteins 16 . IL‐1b and IL‐6 were significantly down‐regulated, while TNF‐a, IL‐1RA, and TLR2 were significantly up‐regulated.…”

“…20 Exposure of normal pony tendinous tissue to ESWT led to down-regulation of MMP3 and upregulation of COL1 and MMP14. 15 While it has been widely reported that ESWT affects the inflammatory response, 16,[21][22][23][24][25] the specific cell types responsible for changes in circulating inflammatory proteins have not been identified. WBC can produce pro-and anti-inflammatory proteins as well as other types of proteins, and effects of ESWT on gene transcription have been demonstrated in other tissue types.…”