Vascular endothelial growth factor expression in nasal polyps of aspirin-intolerant patients

Abstract

Objective: To study differences between aspirin-tolerant patients and aspirin-intolerant patients concerning vascular endothelial growth factor (VEGF) expression. Recent publications strongly suggest the involvement of VEGF and its receptors in the pathophysiologic process of nasal polyps.

Design: We subjected 43 polyp specimens to semiquantitative immunohistochemical analysis. We quantified VEGF and its receptors (Flk, Flt, and neuropilin) in all samples. To gain insight into potential VEGF-mediated cellular responses, we determined proliferative (Ki67) and apoptotic (caspase 3) indices.

Patients: Polyp samples were obtained from 22 aspirin-intolerant patients and from 21 aspirin-tolerant patients, and control specimens were obtained from 24 subjects with healthy nasal respiratory mucosa.

Setting: Laboratory; Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.

Main outcome measures: Expression levels of VEGF, VEGF receptors. and proliferative and apoptotic indices.

Results: We found higher expressed levels of VEGF and neuropilin and stronger proliferation in nasal polyps from aspirin-tolerant and aspirin-intolerant patients compared with controls. In polyps from aspirin-intolerant patients, VEGF was expressed at considerably higher levels compared with those from aspirin-tolerant subjects. Apoptotic activity remained unchanged in all 3 groups.

Conclusions: Nasal polyps from aspirin-tolerant and aspirin-intolerant patients are characterized by strong proliferation and high levels of VEGF and neuropilin expression. Nasal polyps from aspirin-intolerant patients show distinctly increased VEGF levels. The relevance of these findings for future therapeutic approaches is yet to be determined.