The Interstitial Cells of the Human Brain. An Atlas of Light and Electron Microscopy

At cerebral level, new results of authors' own investigations presented the description of shape, distribution, and ultrastructural features of interstitial Cajal-like cells in different locations of the human brain (including interstitial cells of subcortical white matter, interstitial cells within the ectocortex of cerebral hemispheres, interstitial cells within the subarachnoid space, interstitial cells surrounding cortical arteries and veins) for comparative morphology and physiology. Surprisingly, some revolutionary ideas emerge from our new observations regarding the ultrastructural characterization of the intracranial interstitial cells, other than classical fibroblasts of the meninges. In fact, from the pia mater to arachnoid, including the subarachnoid space, the interstitial Cajal-like cells are widely distributed, rather than attenuated fibroblasts. A special spatial relationship at the interface of cerebral cortex with leptomeninges seems to be performed by means of this special cellular type, i.e. ICLC, which also contacts smooth muscle cells contained within the pia mater. Moreover, the pia mater itself is composed of cellular elements resembling ICLCs rather than fibroblasts. In addition, the deep layer of the arachnoid contains cells morphologically similar to the ICLCs. Therefore, from the ectocortex to the deepest arachnoid do exist a network of ICLCs. This special network appears to be the main cellular complex at the cerebral surface and regulates numerous functions, with a common denominator: neuroprotective and vasculoprotective functions. The true name for these special cells should be "protectocytes." Read more