S100 proteins in Corpora Amylacea from normal human brain

Corpora amylacea (C.A.) also named polyglucosan bodies (P.B.) are one of the hallmarks of normal brain aging. Although their functions are not yet clear. C.A. increase in number in patients suffering from neurodegenerative diseases. C.A. contain 88% of hexoses and 4% of proteins. Most of the proteins in C.A. are aging or stress proteins such as heat shock proteins, ubiquitinated proteins and advanced glycation end products which are also proinflammatory products. Stimulated by the potential rule played by some S100 proteins in the inflammatory process which may be triggered in C.A., we investigated, by immunohistochemistry, the presence of different S100 proteins (S100A1. S100A2, S100A3, S100A4, S100A5, S100A6, S100A8; S100A9, S100A12 and S100B) in C.A; from normal human brain. Among the ten S100 proteins analyzed, nine (S100A) were detected in C.A. Three S100 proteins (S100A8, S100A9, S100A12) which are highly expressed in activated macrophages and used as inflammatory markers were detected in C.A. S100A8 was, in addition, found in thick neuronal processes from the pens. One (S100B) could not be found in C.A. although it was highly expressed in astrocytes. In C.A.. the staining intensity was estimated by computer-assisted microscopy and gave th; following order: S100A1 congruent to S100A8 congruent to S100A9>S1005 greater than or equal to S100A4>S100A12>S100A6>S100A2=S100A3. The potential inflammatory role-played by S100 proteins in C.A. is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.