Effects of Methotrexate on Vascular Endothelial Growth Factor, Angiopoietin 1, and Angiopoietin 2 in Nasal Polyps

Abstract

Background Methotrexate (MTX) is a very effective treatment for chronic inflammatory diseases, which are often associated with increased angiogenesis. Angiogenesis is dependent on a perfectly coordinated balance between endogenous-positive and -negative regulatory factors, including vascular endothelial growth factor (VEGF) and the angiopoietins (Ang). The aim of this study was to investigate the effects of MTX on levels of VEGF, Ang-1, and Ang-2 in organ-cultured nasal polyps (NPs. Methods To determine the effects of MTX, NP tissues were cultured using an air-liquid interface method. Cultures were maintained in the absence or presence of MTX (10 or 100 micromoles) for 24 hours. Hematoxylin and eosin, and TUNEL (terminal deoxynucleotidyl transferase [Tdt]-mediated dUTP-biotin nick-end labeling) staining were performed to observe apoptosis. Enzyme-linked immunosorbent assay was used to quantify tissue concentrations of VEGF, Ang-1, and Ang-2. Results MTX treatment resulted in marked alterations in inflammatory cells, especially eosinophils. In contrast, the mucosal epithelium, microvessels including arterioles, veins and capillaries, and fibroblasts maintained their structure. TUNEL+ cells (apoptotic cells) were seen in the MTX-treated specimens. The more induction of TUNEL+ cells was observed 100-micromolar MTX-treated specimens. VEGF and Ang-1 levels were significantly lower, and Ang-2 levels were significantly higher in NPs treated with 100-micromolar MTX than in nontreated NPs (p < 0.01. Conclusion MTX may inhibit the growth of NPs via local regulation of VEGF, Ang-1, and Ang-2 protein levels. We suggest that MTX can be used to treat NPs.