Institute of Anatomy and Cell Biology, Università Cattolica Sacro Cuore, Roma, Italy.
J Neurochem. 2012 Mar;120(5):644-59. doi: 10.1111/j.1471-4159.2011.07612.x. Epub 2012 Jan 23.
S100B is a calcium-binding protein concentrated in glial cells, although it has also been detected in definite extra-neural cell types. Its biological role is still debated. When secreted, S100B is believed to have paracrine/autocrine trophic effects at physiological concentrations, but toxic effects at higher concentrations. Elevated S100B levels in biological fluids (CSF, blood, urine, saliva, amniotic fluid) are thus regarded as a biomarker of pathological conditions, including perinatal brain distress, acute brain injury, brain tumors, neuroinflammatory/neurodegenerative disorders, psychiatric disorders. In the majority of these conditions, high S100B levels offer an indicator of cell damage when standard diagnostic procedures are still silent. The key question remains as to whether S100B is merely leaked from injured cells or is released in concomitance with both physiological and pathological conditions, participating at high concentrations in the events leading to cell injury. In this respect, S100B levels in biological fluids have been shown to increase in physiological conditions characterized by stressful physical and mental activity, suggesting that it may be physiologically regulated and raised during conditions of stress, with a putatively active role. This possibility makes this protein a candidate not only for a biomarker but also for a potential therapeutic target.
S100B 是一种钙结合蛋白，主要集中在神经胶质细胞中，但也在某些特定的神经外细胞类型中被检测到。其生物学作用仍存在争议。当分泌时，S100B 被认为在生理浓度下具有旁分泌/自分泌的营养作用，但在更高浓度下具有毒性作用。因此，生物体液（CSF、血液、尿液、唾液、羊水）中 S100B 水平升高被认为是病理状况的生物标志物，包括围产期脑窘迫、急性脑损伤、脑肿瘤、神经炎症/神经退行性疾病、精神疾病。在大多数情况下，当标准诊断程序仍未显示时，高 S100B 水平提供了细胞损伤的指标。关键问题仍然是 S100B 是否只是从受损细胞中泄漏出来，还是与生理和病理状况同时释放出来，在高浓度下参与导致细胞损伤的事件。在这方面，已经表明，在以紧张的身心活动为特征的生理条件下，生物体液中的 S100B 水平会升高，这表明它可能受到生理调节，并在应激条件下升高，具有潜在的积极作用。这种可能性使这种蛋白质不仅成为生物标志物的候选物，也成为潜在的治疗靶点。
