The Special Case of Human Astrocytes

Abstract

In this first issue of Neuroglia, it is highly appropriate that Professor Jorge A. Colombo at the Unit of Applied Neurobiology (UNA, CEMIC-CONICET) in Buenos Aires, Argentina, writes a perspective of idiosyncrasies of astrocytes in the human brain. Much of his work has been focused on the special case of interlaminar astrocytes, so-named because of their long straight processes that traverse the layers of the human cerebral cortex. Notably, interlaminar astrocytes are primate-specific and their evolutionary development is directly related to that of the columnar organization of the cerebral cortex in higher primates. The human brain also contains varicose projection astrocytes or polarized astrocytes which are absent in lower animals. In addition, classical protoplasmic astrocytes dwelling in the brains of humans are ≈15-times larger and immensely more complex than their rodent counterparts. Human astrocytes retain their peculiar morphology even after grafting into rodent brains; that is, they replace the host astrocytes and confer certain cognitive advantages into so-called ‘humanised’ chimeric mice. Recently, a number of innovative studies have highlighted the major differences between human and rodent astrocytes. Nonetheless, these differences are not widely recognized, and we hope that Jorge Colombo’s Perspective and our associated Commentary will help stimulate appreciation of human astrocytes by neuroscientists and glial cell biologists alike.