Expression of structural proteins and angiogenic factors in cerebrovascular anomalies

OBJECTIVE: The goal of this study was to describe the expression of matrix proteins and angiogenic factors in cerebrovascular malformations. METHODS: Forty-six cerebrovascular malformations were immunohistochemically investigated with a battery of staining for five structural proteins (coll agen IV collagen III, smooth muscle actin, fibronectin, and laminin), and t hree angiogenic factors (vascular endothelial growth factor [VEGF], basic f ibroblast growth factor [bFGF], and transforming growth factor alpha[TGF al pha]). The lesions consisted of 34 arteriovenous malformations (AVMs), 10 c avernous malformations (CMs), and 2 venous angiomas. Expression intensity f or each histological layer in the abnormal vessel wall was graded and compa red. RESULTS: AVM endothelia and subendothelia expressed move laminin and collag en IV than the same layers of CMs. Conversely, CMs expressed move fibronect in than AVMs. CM endothelia exhibited more prominent staining for smooth mu scle actin than AVM endothelia. AVMs and CMs expressed VEGF in the endothel ium and subendothelium, and TGF alpha in endothelial and perivascular layer s. However, unlike AVMs, CMs expressed bFGF in the endothelium as well. The brain tissue intermingled within AVMs also expressed growth factors. Modif ied glial cells in the brain tissue adjacent to CMs expressed bFGF and TGF alpha, but not VEGF. Venous angiomas did not express the studied growth fac tors and mainly consisted of structural proteins of angiogenically mature t issue. CONCLUSION: Expression characteristics of structural proteins reveal that A VMs and CMs have different immunohistological properties. This study provid es strong confirmation of previous findings of VEGF and bFGF immunoexpressi on in AVMs and CMs. It adds new information on TGF alpha expression in thes e malformations and on expression of the angiogenic factors in venous angio mas.