Citation

Clarke G, Skandsen T, Zetterberg H, Follestad T, Einarsen C, Vik A, Mollnes TE, Pischke SE, Blennow K, Håberg AK. J. Neurotrauma 2023; ePub(ePub): ePub.

Copyright

(Copyright © 2023, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2023.0419

PMID

38117157

Abstract

The aim of our study was to investigate the biological underpinnings of persistent post-concussion symptoms (PPCS) at 3 months following mild traumatic brain injury (mTBI). Patients (n = 192, 16-60 years) with mTBI, defined as Glasgow Coma Scale (GCS) score between 13 and 15, loss of consciousness (LOC)<30 min and post-traumatic amnesia (PTA)<24 hours were included. Blood samples were collected at admission (within 72 hours), 2 weeks and 3 months. From the blood, concentrations of blood biomarkers associated with CNS damage (GFAP, NFL and tau) and inflammation (IFN, IL-8, eotaxin, MIP-1, MCP-1, IP-10, IL-17A, IL-9, TNF, FGF-basic PDGF and IL-1ra) were obtained. Demographic and injury-related factors investigated were age, sex, GCS score, LOC, PTA duration, traumatic intracranial finding on MRI (within 72 hours), and extracranial injuries. Delta values, i.e., timepoint differences in biomarker concentrations between 2 weeks minus admission and 3 months minus admission, were also calculated. PPCS was assessed with the British Columbia Post-Concussion Symptom Inventory (BC-PSI). In single variable analyses, longer PTA duration and a higher proportion of intracranial findings on MRI were found in the PPCS group, but no single biomarker differentiated those with PPCS from those without. In multivariable models, female sex, longer PTA duration, MRI findings and lower GCS scores were associated with increased risk of PPCS. Inflammation markers, but not GFAP, NFL or tau, were associated with PPCS. At admission, higher concentrations of IL-8 and IL-9 and lower concentrations of TNF, IL-17a, and MCP-1 were associated with greater likelihood of PPCS; at 2 weeks, higher IL-8 and lower IFN were associated with PPCS; at 3 months, higher PDGF was associated with PPCS. Higher delta values of PDGF, IL-17A and FGF-basic at 2 weeks compared to admission, MCP-1 at 3 months compared to admission and TNF at 2 weeks and 3 months compared to admission were associated with greater likelihood of PPCS. Higher IL-9 delta values at both timepoint comparisons were negatively associated with PPCS. Discriminability of individual CNS-injury and inflammation biomarkers for PPCS was around chance level, while the optimal combination of biomarkers yielded AUCs between 0.62 and 0.73. We demonstrate a role of biological factors on PPCS, including both positive and negative effects of inflammation biomarkers that differed based on sampling timepoint after mTBI. PPCS was associated more with acute inflammatory processes, rather than ongoing inflammation or CNS-injury biomarkers. However, the modest discriminative ability of the models suggests other factors are more important in the development of PPCS.

Language: en

Keywords

ADULT BRAIN INJURY; BIOMARKERS; TRAUMATIC BRAIN INJURY; OUTCOME MEASURES; INFLAMMATION