Analysis of Circulating Endostatin and Vascular Endothelial Growth Factor in Patients with Pituitary Adenoma Treated by Stereotactic Radiosurgery: A Preliminary Study

BACKGROUND: The purpose of this study was to investigate plasma levels of endostatin and vascular endothelial growth factor (VEGF) in normal subjects and in patients with pituitary adenoma and to evaluate change in these levels following stereotactic radiosurgery (SRS) for pituitary adenoma. METHODS: Peripheral venous blood was collected from five patients with pituitary adenoma before SRS using Gamma Knife and at the 1 week and 1 month follow-up visits. Plasma endostatin and VEGF levels were measured using commercially available enzyme-linked immunosorbent assay kits. Peripheral blood samples were obtained from 10 healthy volunteers as controls. RESULTS: Mean baseline plasma endostatin level (105.3 ng/mL, range, 97.0-120.2 ng/mL) in patients with pituitary adenoma was higher than that of the healthy controls (86.6 ng/mL, range, 71.3-98.2 ng/mL) (p=0.001). Mean plasma VEGF level was 89.5 pg/mL (range, 24.1-171.8 pg/mL) in patients with pituitary adenoma at baseline and 29.3 pg/mL (range, 9.2-64.3 pg/mL) in the control group (p=0.050). Plasma endostatin level changed to 106.6 ng/mL 1 week after SRS and decreased to 95.9 ng/mL after 1 month. Plasma VEGF level following SRS decreased to 74.1 pg/mL after 1 week and 79.0 pg/mL after 1 month. There was a trend toward decreased plasma endostatin and VEGF concentrations 1 month after SRS compared to baseline levels (p=0.195, p=0.812, respectively). CONCLUSION: Plasma endostatin and VEGF levels in patients with pituitary adenoma were significantly elevated over controls at baseline, which decreased from baseline to 1 month after SRS for pituitary adenomas.