Traumatic brain injury increases plasma astrocyte-derived exosome levels of neurotoxic complement proteins.
Possible involvement of complement (C) systems in the pathogenesis of traumatic brain injury (TBI) was investigated by quantifying Cproteins in plasma astrocyte-derived exosomes (ADEs) of subjects with sports-related TBI (sTBI) and TBI in military veterans (mtTBI) without cognitive impairment. All sTBI subjects (n = 24) had mild injuries, whereas eight of the mtTBI subjects had moderate, and 17 had mild injuries. Plasma levels of ADEs were decreased after acute sTBI and returned to normal within months. Cprotein levels in ADEs were from 12- to 35-fold higher than the corresponding levels in neuron-derived exosomes. CD81 exosome marker-normalized ADE levels of classical pathway C4b, alternative pathway factor D and Bb, lectin pathway mannose-binding lectin (MBL), and shared neurotoxic effectors C3b and C5b-9 terminal C complex were significantly higher and those of C regulatory proteins CR1 and CD59 were lower in the first week of acute sTBI (n = 12) than in controls (n = 12). Most C abnormalities were no longer detected in chronic sTBI at 3-12 months after acute sTBI, except for elevated levels of factor D, Bb, and MBL. In contrast, significant elevations of ADE levels of C4b, factor D, Bb, MBL, C3b and C5b-9 terminal C complex, and depressions of CR1 and CD59 relative to those of controls were observed after 1-4 years in early chronic mtTBI (n = 10) and persisted for decades except for normalization of Bb, MBL, and CD59 in late chronic mtTBI (n = 15). Complement inhibitors may be useful therapeutically in acute TBI and post-concussion syndrome.
['Goetzl|Edward J|EJ|', 'Yaffe|Kristine|K|', 'Peltz|Carrie B|CB|', 'Ledreux|Aurélie|A|', 'Gorgens|Kim|K|', 'Davidson|Bradley|B|', 'Granholm|Ann-Charlotte|AC|', 'Mustapic|Maja|M|', 'Kapogiannis|Dimitrios|D|', 'Tweedie|David|D|', 'Greig|Nigel H|NH|']
D001253:Astrocytes D015415:Biomarkers D000070642:Brain Injuries, Traumatic D002097:C-Reactive Protein D003165:Complement System Proteins D055354:Exosomes D005260:Female D006801:Humans D008297:Male D055815:Young Adult
extracellular vesicles neurodegeneration neuroinflammation