P-778 - S100B Serum protein does not have a circadian rhythm in healthy subjects

Abstract

Introduction: Circadianity is a characteristic of several human biological variables, such as testosterone, melatonin and cortisol. There is little information whether or not S100B serum protein presents a circadian rhythm. Material and methods: 44 healthy subjects (24 female and 20 male, age 39.7 ± 9.4) participated in the study. Blood was sampled in July at 09:00, 12:00 and 24:00 h. Blood was centrifuged and serum was aliquot in Eppendorf tubes and frozen at-70º C. Serum S100B was measured by ELISA. Results: Serum S100B concentrations at 09:00 (56.3 ± 18.1 pg/ml), 12:00 (53.8 ± 23.1 pg/ml) and 24:00 h. (55.3 ± 20.3 pg/ml) were not significantly different. Conclusions: Our results point to the absence of a circadian rhythm of S100B serum protein concentrations. The lack of the disadvantage may allow researchers on this area to sample subjects at any time of the day.

Evaluation of Serum S100B Levels in Male Children Younger than 6 Years Old with Autism Spectrum Disorder: A Psychiatric and Biochemical Perspective

“…Ikeda and Umemura (24) showed that serum S100B protein levels were not affected by the circadian rhythm. Likewise, Morera-fumero et al (6) found no circadian rhythm in S100B levels. In the same study different S100B values were seen due to the season, whether it is summer or winter, with higher values in summer than in winter.…”

“…The intracellular role of S100B includes participation in cell proliferation, differentiation, transcription, survival, and enzyme activities, whereas its extracellular role is exerted mostly through receptors for advanced glycation end-products (RAGE) and triggering intracellular signaling cascade, leading to processes such as neuroinflammation and neurodegeneration (3)(4)(5). It has been confirmed that the action of S100B is either neurotrophic/neuroprotective or neurotoxic/apoptotic depending on the concentration (3,6). In neural cultures neurotrophic effects have been demonstrated at nanomolar levels and apoptotic effects at micromolar levels (5).…”