Substance P and neurokinin 1 receptors as potential therapeutic targets in children with OSA

Background: Increased substance P (SP) levels and abundant expression of neurokinin (NK) 1 receptor in adenotonsillar tissues of children with OSA but not recurrent tonsillar infection (RI) suggest that NK1 antagonists could be useful in treating OSA. Methods: The effects of SP and the NK1 antagonist GR-82334 were examined on mixed cell cultures prepared from dissociated tonsils harvested intraoperatively from children with OSA and RI. Proliferation was assessed by [3H]-thymidine or 5-ethynyl-29-deoxyuridine incorporation, and infl ammatory cytokine production (tumor necrosis factor [TNF]- α , IL-6, IL-1 β ) was assessed in supernatants by enzyme-linked immunosorbent assay. Results: SP elicited dose-dependent increases in tonsillar cell proliferation in mixed cell cultures from children with OSA but not with RI ( P < .0001). The NK1 antagonist exhibited dose-dependent reductions in cellular proliferative rates in OSA-derived cell cultures but not in RI-derived mixed cell cultures ( P < .00001). SP treatment was associated with increased TNF- α and IL-6 production, and GR-82334 abrogated SP effects, as well as reduced basal cytokine release ( P < .0001). Conclusions: SP pathways appear to underlie intrinsic proliferative and infl ammatory signaling pathways in tonsillar tissues from children with OSA but not with RI. Selective disruption of these pathways may provide nonsurgical alternatives for prevention and treatment of pediatric OSA.