title: Serum Glial Fibrillary Acidic Protein Predicts Tissue Glial Fibrillary Acidic Protein Break-Down Products and Therapeutic Efficacy after Penetrating Ballistic-Like Brain Injury.
abstract: Acute traumatic brain injury (TBI) is associated with neurological dysfunction, changes in brain proteins, and increased serum biomarkers. However, the relationship between these brain proteins and serum biomarkers, and the ability of these serum biomarkers to indicate a neuroprotective/therapeutic response, remains elusive. Penetrating ballistic-like brain injury (PBBI) was used to systematically analyze several key TBI biomarkers, glial fibrillary acidic protein (GFAP) and its break-down products (BDPs)-ubiquitin C-terminal hydrolase-L1 (UCH-L1), α-II spectrin, and α-II spectrin BDPs (SBDPs)-in brain tissues and serum during an extended acute-subacute time-frame. In addition, neurological improvement and serum GFAP theranostic value was evaluated after neuroprotective treatment. In brain tissues, total GFAP increased more than three-fold 2 to 7 d after PBBI. However, this change was primarily due to GFAP-BDPs which increased to 2.7-4.8 arbitrary units (AU). Alpha-II spectrin was nearly ablated 3 d after PBBI, but somewhat recovered after 7 d. In conjunction with α-II spectrin loss, SBDP-145/150 increased approximately three-fold 2 to 7 d after PBBI (vs. sham, p<0.05). UCH-L1 protein levels were slightly decreased 7 d after PBBI but otherwise were unaffected. Serum GFAP was elevated by 3.2- to 8.8-fold at 2 to 4 h (vs. sham; p<0.05) and the 4 h increase was strongly correlated to 3 d GFAP-BDP abundance (r=0.66; p<0.05). Serum GFAP showed such a strong injury effect that it also was evaluated after therapeutic intervention with cyclosporin A (CsA). Administration of 2.5 mg/kg CsA significantly reduced serum GFAP elevation by 22.4-fold 2 h after PBBI (vs. PBBI+vehicle; p<0.05) and improved neurological function 1 d post-injury. Serum biomarkers, particularly GFAP, may be correlative tools of brain protein changes and feasible theranostic markers of TBI progression and recovery.
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: Angela M
authors: AM
authors: Boutté
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: Ying
authors: Y
authors: Deng-Bryant
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: David
authors: D
authors: Johnson
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: Frank C
authors: FC
authors: Tortella
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: Jitendra R
authors: JR
authors: Dave
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: Deborah A
authors: DA
authors: Shear
authors: Brain Trauma Neuroprotection and Neurorestoration Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research , Silver Spring, Maryland.
authors: Kara E
authors: KE
authors: Schmid
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D004195:Disease Models, Animal; D005904:Glial Fibrillary Acidic Protein / Q000097:blood / Q000378:metabolism*; D020197:Head Injuries, Penetrating / Q000097:blood / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013049:Spectrin / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase / Q000097:blood / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D013049:Spectrin; D043222:Ubiquitin Thiolesterase
keywords: CsA; GFAP-BDP; TBI; biomarker; neuroprotection; proteolysis, SBDP; serum