Expression of Placenta Growth Factor mRNA Transcripts and Protein in Nasal Mucosa and Nasal Polyps

ABSTRACT

Placenta growth factor (PIGF) was originally described as a placenta produced homodimeric protein that shares substantial structural similarity with vascular endothelial growth factor (VEGF). It is becoming increasingly evident that PIGF may directly or indirectly modulate several key vascular events in various tissues. These include angiogenesis or vasculogenesis, vascular maturation and stabilization, vascular permeability, and endothelial cell survival. Inflammatory reaction in the nasal mucosa increases mucosal vascular permeability, resulting in edematous nasal mucosa with polypoid change. In this respect, PIGF may play a role in the formation of nasal polyp. In the present study we evaluated the expression of PIGF mRNA and protein in human inferior turbinate mucosa and nasal polyp. The expression and localization of PlGF mRNA and protein were investigated in the inferior turbinate mucosa and nasal polyps using reverse transcription-polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry. These results showed that the mRNA transcripts and protein for PlGF are expressed in human turbinate mucosa and nasal polyps. Semiquantitative RT-PCR revealed that PIGF mRNA in nasal polyps increased in its expression level than that in nasal turbinate mucosa. Likewise, immunoblot analysis demonstrated a higher expression of PIGF protein in nasal polyp tissues, compared with that of the nasal turbinate mucosa. However, immunohistochemical findings revealed that PlGF is localized in the endothelial lining of blood vessels in the inferior turbinate mucosa, whereas it is expressed in the epithelial cells of nasal polyps. These results indicate that PlGF mRNA and protein are expressed in normal turbinate mucosa and nasal polyp. Further, based on the fact showing that the expression site of PIGF is different in both tissues, the action mechanism of PIGF may be different in human nasal mucosa and nasal polyp. That is, the PIGF may play a role in the physiological function of normal nasal mucosa, possibly the maintenance of blood vessel and in the pathogenesis of nasal polyp formation.