Transformation of Adult Schwann Cells Into Macrophages. *

Abstract

Conclusions

(1) The adult Schwann cell is capable of a wide range of modulation in the course of which it can assume numerous shapes and characters often associated in neuropathology with distinct cell types. (2) Schwann cells presumably are a major source of macrophages during Wallerian nerve degeneration, and their control becomes a prime consideration in nerve regeneration.⁷ (3) The active role of the Schwann cell in removing myelin by phagocytosis and digestion has been experimentally verified. (4) The filamentous shape of the spindletype Schwann cell makes it a superb guide for axons.⁸ Its dimensions and staining properties are very close to those of axon sprouts, which suggests one source of error in past unfounded claims of “autogenous” nerve regeneration. (5) The results place increased emphasis on the great versatility of even the adult cell, within the limited potentialities of its strain, in response to the composition and microstructural organization of its environment.⁵