nInteraction of APOE4 alleles and PET Tau Imaging In Former Contact Sport Athletes

Abstract Background : Genetic polymorphisms like apolipoprotein E (APOE) and microtubule-associated protein tau (MAPT) genes increase the risk of neurodegeneration. Methods : 38 former players (age 52.63±14.02) of contact sports underwent neuroimaging, biofluid collection, and comprehensive neuropsychological assessment. The [F-18]AV-1451 tracer signal was compared in the cortical grey matter between APOE4 allele carriers and non-carriers as well as carriers of MAPT H1H1 vs non-H1H1. Participants were then divided into the high (N=13) and low (N=13) groups based on cortical PET tau standard uptake value ratios (SUVRs) for comparison. Findings : Cortical grey matter PET tau SUVR values were significantly higher in APOE4 carriers compared to non-carriers (p=0.020). In contrast, there was no significant difference in SUVR between MAPT H1H1 vs non-H1H1 carrier genes (p=1.00). There was a significantly higher APOE4 allele frequency in the high cortical grey matter PET tau group, comparing to low cortical grey matter PET tau group (p=0.048). No significant difference in neuropsychological function was found between APOE4 allele carriers and non-carriers. Interpretation : There is an association between higher cortical grey matter tau burden as seen with [F-18]AV-1451 PET tracer SUVR, and the APOE4 allele in former professional and semi-professional players at high risk of concussions. APOE4 allele may be a risk factor for tau accumulation in former contact sports athletes at high risk of neurodegeneration. Funding : Toronto General and Western Hospital Foundations; Weston Brain Institute; Canadian Consortium on Neurodegeneration in Aging; Krembil Research Institute. There was no role of the funders in this study.