Congenital vascular malformations – cerebral lesions differ from extracranial lesions by their immune expression of the glucose transporter protein GLUT1

Abstract

Cerebral vascular malformations were investigated for the presence of the glucose transporter protein GLUT1, which is normally expressed in endothelial cells of the pre-existing microvasculature of the brain and absent in the vasculature of the choroid plexus and extracranial vasculature without a barrier function. Extracranial arteriovenous malformations (AVM) are known to show an absence of GLUT1 expression which distinguishes them from infantile hemangioma of skin and soft tissue. The expression of GLUT1 in cerebrovascular malformations is not systematically investigated. Paraffin-embedded sections of cerebral AVM (4), including one choroid plexus AVM, cerebral cavernous malformations (CCM, 3) and extracranial (facial) AVM (3) were immunostained with anti-CD31 and GLUT1 in doublestaining procedure which was further analyzed with the use of spectral analysis software. All 7 cases of cerebral vascular malformations showed colocalization of GLUT1/CD31 of endothelial cells of the vessels within the malformation. Only in the extracranial AVM expression of GLUT1 was completely absent. Cerebral AVM differ from extracranial AVM by their endothelial immunoexpression of GLUT1, indicating that the vessels of these malformations retain the endothelial phenotype of the local vascular beds from which they are derived during embryogenesis.