Netto Cristina B O, Conte Sabrina, Leite Marina C, Pires Caroline, Martins Tiago L, Vidal Penélope, Benfato Mara S, Giugliani Roberto, Gonçalves Carlos-Alberto
Dept. Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Brazil.
Arch Med Res. 2006 Jul;37(5):683-6. doi: 10.1016/j.arcmed.2005.11.005.
S100B is a calcium-binding protein expressed and secreted by astrocytes; serum and cerebrospinal fluid (CSF) S100B elevation has been proposed as an index of brain damage. However, other tissues are shown to produce this protein and the clinical significance of serum S100B elevation has been discussed.
We investigated the levels of serum and CSF S100B in fasting Wistar rats. Animals were divided into two groups, control and fasting for 48 h, and S100B levels in serum and CSF were determined by ELISA. S100B secretion in dissociated epididymal fat cells was investigated in the presence of epinephrine.
We observed a significant >2-fold increase of S100B levels in serum of fasting rats, without changes in its CSF content. Moreover, we demonstrated in vitro epinephrine stimulated S100B release from fat cells.
Present results reinforce that extracerebral sources of S100B, particularly adipocytes, contribute to its serum levels and support the idea that caution is needed when interpreting serum S100B increase as a clinical marker of brain damage.
S100B是一种由星形胶质细胞表达和分泌的钙结合蛋白；血清和脑脊液（CSF）中S100B水平升高已被提议作为脑损伤的一个指标。然而，其他组织也被证明能产生这种蛋白，并且血清S100B水平升高的临床意义一直存在争议。
我们研究了禁食的Wistar大鼠血清和脑脊液中S100B的水平。将动物分为两组，对照组和禁食48小时组，通过酶联免疫吸附测定法（ELISA）测定血清和脑脊液中S100B的水平。在肾上腺素存在的情况下，研究离体附睾脂肪细胞中S100B的分泌情况。
我们观察到禁食大鼠血清中S100B水平显著增加了两倍多，而其脑脊液含量没有变化。此外，我们在体外证明肾上腺素能刺激脂肪细胞释放S100B。
目前的结果强化了S100B的脑外来源，特别是脂肪细胞，对其血清水平有贡献这一观点，并支持在将血清S100B升高解释为脑损伤临床标志物时需要谨慎的观点。
