Immunochemistry and serum values of S-100B, glial fibrillary acidic protein, and hyperphosphorylated neurofilaments in brain injuries
Abstract
Introduction: Traumatic brain injury (TBI) triggers a series of reactions resulting in cytoskeletal-related changes varying between focal and diffuse injuries. Methods: The patients (n=38) were divided into group of diffuse axonal injuries (DAI, n=10) and focal (n=28) injuries.
Serum hyperphosphorylated neurofilaments (NF-H) and glial fibrillary acidic protein (GFAP) were measured by Biovendor immunoassay, and serum S-100B protein was measured by Cobas e411 (Roche) by immunoassay. Immunohistochemistry was performed with monoclonal antibodies (Chemicon, USA).
Results: The median serum S-100B concentration was higher in patients with focal mass lesions (1.72±0.4 μg/l vs. 0.37±0.1 μg/l, p<0,05) compared to patients with DAI during 10 days of hospitalisation. With respect to all patients, the highest peak of serum S-100B values (4.21±1.1 μg/l) and GFAP (8.58±2.4 μg/l) were found in expansive lesions.
The median serum NF-H was higher in DAI compared to focal TBI (0.625±0.14 vs 0.139±0.02 ng/l, p<0.05) during all 10 days after admission. Further, immunohistochemical investigation, in deceased patients with DAI , using NF-H antibody proved positive varicose and waving axons, and retraction balls.
Time-dependent profile of serum NF-H demonstrated the increase of values within 4th up to 10th day in both groups. Values ranged from 0.263 up to 1.325 ng/l in DAI, and from 0.103 up to 1.108 ng/l in focal injuries.
Patients with expansive contusions had similar levels of serum NF-H as patients without expansive lesions. Immunohistochemistry of cytoskeletal proteins presented strong positive staining of vinculin, vimentin in vessels, GFAP, and S-100B in DAI compared to weak staining in expansive lesions.
Conclusion: The time-profile kinetics of all markers may reflect different types of pathophysiological changes of the BBB or axonal damage in focal and diffuse injuries.
