Work

Inflammatory blood biomarker response after controlled subconcussive head impacts: a pilot randomized controlled trial

Year: 2019

Type: preprint

Study designs: Randomized Controlled Trial, Clinical Trial

Abstract: Background: Chronic neuroinflammation has been implicated as a possible contributing mechanism in the development and progression of chronic traumatic encephalopathy. This neurodegenerative condition has been associated with longterm, repetitive exposure to subconcussive head impacts, defined as head impacts that do not induce clinical signs or symptoms of concussion. However, there is a gap in knowledge surrounding the acute inflammatory response to subconcussive head impacts. The present study aimed to test our hypothesis that plasma levels of two proinflammatory markers (CCL11, CCL2) and one anti-inflammatory marker (IL-10) would be significantly elevated after 10 repetitions of controlled subconcussive head impacts. Methods: This randomized controlled trial included 39 healthy adult soccer players who were randomized into a heading (n=22) or kicking-control group (n=17). The heading group executed 10 headers with soccer balls projected at a speed of 25mph. The kicking-control group followed the same protocol with 10 kicks. Plasma samples were collected pre-, 0h post-, 2h post-, and 24h post-intervention. Samples were assayed for CCL11, CCL2, and IL-10, which are inflammatory markers that have shown to upregulate following traumatic brain injury. The longitudinal inflammatory marker data were analyzed using mixed-effect regression models. Results: There were no significant group differences in the changes of plasma CCL11, CCL2, or IL-10 levels at post-intervention time points as compared with pre-intervention baseline. However, within the heading group, there was a statistically significant interaction between time and years of soccer heading experience in plasma CCL11 levels at 24h post-intervention (2.0 pg/mL per a single year of soccer heading experience, 95% CI: 0.8, 3.1, p = 0.001). Conclusions: Ten soccer headings did not modulate the acute response in the three inflammatory marker levels compared against a kicking-control group. However, the acute CCL11 response may be influenced by the duration of prior exposure to subconcussive head impacts. Our data provide a precedent for future field studies that prospectively track head impact exposure and the time course of changes in circulating CCL11.

Source: Research Square

DOI: 10.21203/rs.2.15214/v1