Vasoactive intestinal peptide receptor expression in chronic periapical lesions J. Caviedes-Bucheli 1 , M. M. Azuero-Holguı´n 1 , G. C. Moreno 1 , I. L. Gonza ´ lez 2 , E. Mateu 2 , J. F. Salazar 2 & H. R. Munoz 2 Department of 1 Graduate Studies and 2 Endodontic, School of Dentistry, Pontificia Universidad Javeriana, Bogota, Colombia Abstract Caviedes-Bucheli J, Azuero-Holguı ´n MM, Moreno GC, Gonza ´ lez IL, Mateu E, Salazar JF, Munoz HR. Vasoactive intestinal peptide receptor expression in chronic periapical lesions. International Endodontic Journal, 40, 521–525, 2007. Aim To use radioreceptor analysis for evaluating whether vasoactive intestinal peptide (VIP) receptors are present in chronic periapical lesions and to deter- mine whether differences in its expression are found according to the size of the lesions. Methodology Twelve periapical lesions were obtained from teeth diagnosed with chronic apical periodontitis and indicated for endodontic surgery; they were classified according to the size of the lesion in two groups of six samples (lesion size greater or smaller than 5 mm), and then processed and labelled with 125 I- VIP. Binding sites were identified by 125 I-VIP and standard VIP competition assays. Mann–Whitney’s test was used to establish statistically significant differences in the VIP receptor expression between groups. Results Vasoactive intestinal peptide receptor expres- sion was found in all periapical lesion samples. There was a statistically significantly higher expression in periapical lesions <5 mm (P < 0.001). Conclusion Vasoactive intestinal peptide receptors were expressed in chronic periapical lesions with levels inversely proportional to lesion size. Keywords: neuropeptides, periapical lesion, vaso- active intestinal polypeptide, VIP-receptor. Received 12 April 2006; accepted 14 December 2006 Introduction Chronic periapical lesions develop as an inflammatory response to pulp tissue necrosis to prevent dissemin- ation of bacteria and their toxins infection send towards the periapical tissues. Although a chronic periapical lesion is a radiographic finding, histologically they are classified as granulomas and periapical cysts (Marton & Kiss 1993, Rodini & Lara 2001, de Oliveira Rodini et al. 2004). Periapical lesions, such as granulomas and cysts, are densely innervated (Leonardi et al. 2003), comprising an inflammatory exudate with abundant macrophages, lymphocytes, polymorphonuclear leukocytes and plas- ma cells (Marton & Kiss 1993). Nervous and immune systems become intimately related during periapical tissue inflammatory responses (Segura et al. 1996). These interactions are facilitated by anatomical con- nections and chemical mediators such as neuropeptides and cytokines released and recognized by both systems (Gozes et al. 1999). Vasoactive intestinal peptide (VIP) has been associ- ated with the development of chronic periapical lesions suggesting that it could participate in their growth and maturation (Azuero-Holguin et al. 2003). VIP is a parasympathetic neuropeptide consisting of 28 amino acids, distributed throughout the central and peripheral nervous systems (Gozes et al. 1999). This neuropeptide has a vasodilator effect and is expressed in healthy and inflamed human dental pulps (Caviedes-Bucheli et al. Correspondence: Javier Caviedes-Bucheli, DDS, MSc, School of Dentistry, Pontificia Universidad Javeriana, Cra 7 No. 40-62 Building 26, Bogota, Colombia (Tel.: +57 (1) 3208320 Ext. 2889; e-mail: javiercaviedes@cable.net.co). doi:10.1111/j.1365-2591.2007.01250.x ª 2007 International Endodontic Journal International Endodontic Journal, 40, 521–525, 2007 521