Immunohistochemical study in dural arteriovenous fistulas and possible role of local hypoxia for the de novo formation of dural arteriovenous fistulas.
OBJECTIVE
Although previous clinical and experimental studies investigated the pathogenesis of dural arteriovenous fistulas (DAVFs), the biological process leading to intracranial DAVFs so far remains unknown. In this study, we investigated the expression of vascular growth factors in order to elucidate the possible role of these factors in the development of DAVFs.


METHODS
We examined the histological features, proliferative and angiogenic capacities of the tissue specimens obtained from eight patients who underwent surgery at our institution. Immunohistochemical staining for vascular endothelial growth factor (VEGF), its receptors Flk-1 and Flt-1, transforming growth factor alpha (TGFalpha), basic fibroblast growth factor (bFGF), hypoxia inducible factor 1alpha (Hif-1alpha), MIB-1 and proliferating cell nuclear antigen (PCNA) was performed using standard immunohistochemical techniques.


RESULTS
A positive immunostaining was found for all antibodies studied except MIB-1, whereas nuclear endothelial expression of PCNA was observed in only 3/8 cases. Hif-1alpha and VEGF stained positive in all of the available specimens (7/7). Flk-1 showed a positive immunoreaction in only 2/8 cases and Flt-1 in 5/7 cases. TGFalpha and bFGF were expressed in the majority (6/8) of cases.


CONCLUSIONS
These results indicate the possible role of local tissue hypoxia as the initial step causing neoangiogenesis and a low degree of endothelial proliferation in DAVFs. Such hypoxia might be caused by venous hypertension or venous thrombosis as it was previously suggested by other authors.
Tirakotai
Wuttipong
W
Department of Neurosurgery, Philipps University, Baldingerstrasse, 35033 Marburg, Germany.
Bertalanffy
Helmut
H
Liu-Guan
Bian
B
Farhoud
Ahmed
A
Sure
Ulrich
U
D000328:Adult; D020785:Central Nervous System Vascular Malformations / Q000473:pathology*; D004730:Endothelium, Vascular / Q000473:pathology; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000032:analysis*; D006801:Humans; D000860:Hypoxia / Q000473:pathology*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000032:analysis*; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis*; D016211:Transforming Growth Factor alpha / Q000032:analysis*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis*; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000032:analysis*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000032:analysis*
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D018809:Proliferating Cell Nuclear Antigen; D016211:Transforming Growth Factor alpha; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2