Identification of the nasal mucosa as a new target for leptin action.

Unlabelled: The aim of this study was to examine systemic and local nasal leptin and leptin receptor expression in patients with nasal polyposis and healthy controls.

Methods And Results: Serum leptin and soluble leptin receptor levels were examined by enzyme-linked immunosorbent assay (ELISA). The presence of leptin and leptin receptor mRNA was investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), and tissue leptin and leptin receptor protein expression was analysed by immunohistochemistry and ELISA. Serum levels of biologically active leptin were significantly elevated in patients with nasal polyps compared with control subjects. These serum leptin levels were strongly correlated with the levels found in tissue in both study groups, although leptin was not significantly elevated in nasal polyp tissue. Using RT-PCR, we showed that both leptin and its receptors were produced in nasal mucosa. Finally, immunohistochemistry showed that leptin and leptin receptor protein were expressed in several cells of the normal and inflamed nasal mucosa.

Conclusions: Leptin receptors and their biological ligand leptin are expressed in the nasal mucosa, suggesting a possible role in upper airway immunology.