Astrogliosis and blood vessel development during human spinal cord myelination

The aim of our study was to investigate a relationship between vessel development, astrogliosis and myelination in humans. We examined spinal cords of human fetuses and infants using immunohistochemical methods with antibodies against Myelin Basic Protein (MBP), Glial Fibrillary Acidic Protein (GFAP) and lectin Ulex Europaeus Type 1 (UEA-1). Our investigation showed that in parallel to the increase of MBP reactivity in the spinal cord white matter more GFAP-immunoreactive astrocytes appeared. Reaction of vessel endothelium with lectin UEA-1 revealed the temporal increase of vascularization in the course of the spinal cord tracts myelination in fetuses. In the postnatal period when the myelination is nearly morphologically completed, the spinal cord white matter was poorly vascularized although GFAP-immunoreactive cells were still relatively numerous. We suggested that the increase of vascularization and astrogliosis observed during spinal cord tracts myelination may be connected with their participation in process of myelin sheath formation via, among others, local secretion of growth factors necessary for normal myelin development.