Biological and methodological features of the measurement of S100B, a putative marker of brain injury.
The S100B astroglial protein is widely used as a parameter of glial activation and/or death in several conditions of brain injury. Cerebrospinal fluid and serum S100B variations have been proposed to evaluate clinical outcomes in these situations. Here, we briefly broach some aspects, commonly not sufficiently valorized, concerning the biology and measurements of this protein. S100B has molecular targets and activities in and outside of astrocytes, and variations of intra and extracellular content are not necessarily coupled. We discuss the extracellular origin of this protein in brain tissue, as well as extracerebral sources of this protein in serum, comparing it with other available protein markers of brain damage. The superestimation of the heterodimer S100A1-B in the current clinical literature is also analyzed. We affirm that poor dualistic views that consider S100B elevation as "bad" or "good" simplify clinical practice and delay our comprehension of the role of this protein, both in physiological conditions and in brain disorders.
Gonçalves
Carlos-Alberto
CA
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. casg@ufrgs.br
Leite
Marina Concli
MC
Nardin
Patrícia
P
D000918:Antibody Specificity; D015415:Biomarkers / Q000032:analysis; D001930:Brain Injuries / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D009414:Nerve Growth Factors / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D015203:Reproducibility of Results; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000032:analysis* / Q000235:genetics; D014158:Transcription, Genetic
D015415:Biomarkers; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human