Hypoxia inducible factor expression and angiogenesis – Analysis in the pituitary gland and patterns of death

Abstract

Background/Aim: We investigated the expression of angiogenesis and hypoxia markers in the adenohypophysis and neurohypophysis of patients who died from various acute or chronic diseases. Materials and Methods: Paraffin-embedded material of pituitary glands (97 patients) was investigated immunohistochemically for vascular density (CD31) and the expression of vascular endothelial growth factor (VEGF) and of hypoxia inducible factors HIF1α and HIF2α. Results: Vascular density, and HIF1α/HIF2α reactivity is directly related with VEGF expression in the pituitary gland, suggesting that the HIF pathway may regulate the vascular density and blood flow in the gland under hypoxic conditions. HIF2α appears to be a key regulator in neurohypophysis, whilst in adenohypophysis HIF1α and HIF2α are equally expressed. Chronic conditions, including alcoholism and substance abuse, seem to activate the HIF pathway in both neuro- and adeno-hypophysis. Conclusion: The HIF pathway has an important role in regulating vascular density and blood flow in the pituitary gland.