Acellular Human Dermal Allograft as a Graft for Nasal Septal Perforation Reconstruction.

BACKGROUND: Nasal septal perforations pose a troubling source of morbidity for patients and a difficult problem for the otolaryngologist. Multiple surgical techniques have been tried, with inconsistent success. Prosthetic nasal buttons also have limitations, including patient intolerance and dissatisfaction. Acellular human dermal allograft (AlloDerm) has been described as an alternative material for septal perforation repair. The authors studied objective and subjective outcomes, including quantification of the patient's symptoms in septal perforation repair with AlloDerm. METHODS: The authors performed a prospective cohort study of 12 patients with 1- to 2-cm anterior septal perforations who were recruited from a tertiary care practice. Patients with admitted smoking or cocaine use in the previous 3 months or vascular or granulomatous diseases were excluded. Subjective scores on the Sino-nasal Outcome Test-22, along with objective nasal endoscopy and acoustic rhinometry measures, were collected at baseline and 2, 4, and 12 weeks postoperatively. Patients were followed for reperforation 9 to 20 months postoperatively. Data were normalized to baseline values and analyzed using analysis of variance and Bonferroni correction. RESULTS: Successful closure of the septal perforation was obtained in 10 of 12 patients and confirmed with rigid nasal endoscopy. Nasal symptom scores (Sino-nasal Outcome Test-22 ) were significantly reduced to 52.8 percent (95 percent CI, 35.1 to 70.5 percent; p < 0.01) of baseline symptoms at 4 weeks postoperatively. At 12 weeks postoperatively, symptoms were measured at 26.6 percent (95 percent CI, 10.9 to 42.1 percent; p < 0.01) of baseline symptoms. Acoustic rhinometry confirmed perforation closure, demonstrating a reduction in cross-sectional nasal area from baseline of 55.1 percent (95 percent CI, 37.7 to 66.8 percent; p < 0.01). CONCLUSION: This is the first study to use objective and subjective measurements to confirm success with acellular dermis allograft as an adjunct for septal perforation repair, demonstrating a statistically significant reduction in patient nasal symptoms following repair. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Cystic fibrosis transmembrane conductance regulator dysfunction in VIP knockout mice.

Vasoactive intestinal peptide (VIP), a neuropeptide, controls multiple functions in exocrine tissues, including inflammation, and relaxation of airway and vascular smooth muscles, and regulates CFTR-dependent secretion, which contributes to mucus hydration and local innate defense of the lung. We had previously reported that VIP stimulates the VPAC1 receptor, PKCϵ signaling cascade, and increases CFTR stability and function at the apical membrane of airway epithelial cells by reducing its internalization rate. Moreover, prolonged VIP stimulation corrects the molecular defects associated with F508del, the most common CFTR mutation responsible for the genetic disease cystic fibrosis. In the present study, we have examined the impact of the absence of VIP on CFTR maturation, cellular localization, and function in vivo using VIP knockout mice. We have conducted pathological assessments and detected signs of lung and intestinal disease. Immunodetection methods have shown that the absence of VIP results in CFTR intracellular retention despite normal expression and maturation levels. A subsequent loss of CFTR-dependent chloride current was measured in functional assays with Ussing chamber analysis of the small intestine ex vivo, creating a cystic fibrosis-like condition. Interestingly, intraperitoneal administration of VIP corrected tissue abnormalities, close to the wild-type phenotype, as well as associated defects in the vital CFTR protein. The results show in vivo a primary role for VIP chronic exposure in CFTR membrane stability and function and confirm in vitro data.

VIP-dependent increase in F508del-CFTR membrane localization is mediated by PKCε.

The most common cystic fibrosis causing mutation F508del induces early degradation and reduced trafficking of cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels to the apical membrane of epithelial cells. In the human nasal epithelial cells JME/CF15, we previously reported that vasoactive intestinal peptide (VIP) exposure corrects trafficking and membrane insertion of functional F508del-CFTR channels at 37°C. Correction of trafficking was PKA dependent, whereas enhanced membrane localization involved PKC. In the present study, we have identified PKCε as the isoform involved in VIP-dependent F508del-CFTR membrane insertion. Iodide effluxes were used to monitor the presence of VIP-rescued functional F508del-CFTR channels at the surface of JME/CF15 cells maintained at 37°C. Iodide efflux peaks measured in response to stimulation with forskolin were insensitive to PKC α, ß, γ, δ, ζ inhibitors. In contrast, efflux peaks were completely inhibited by pretreatment with the PKCε inhibitor peptide EAVSLKPT with an IC(50) of 4.9 µM or by PKCε small interfering RNA (siRNA). Immunostaining and confocal microscopy confirmed that membrane localization of F508del-CFTR induced by VIP was abolished in the presence of EAVSLKPT but not with other isoform inhibitors. In recombinant baby hamster kidney cells, endogenously expressing PKCε but no VIP receptor, wild-type, and F508del-CFTR sensitivity to cpt-cAMP stimulation was increased by PMA treatment. Biotinylation assays and immunoblots confirmed that PMA (0.5-2 h) induced a greater than threefold increase in membrane CFTR, whereas forskolin had no effect. The PMA effect was abolished by specifically inhibiting PKCε (EAVSLKPT IC(50) = 5.7 µM) but not other PKC isoforms. Taken together, these results indicate that stimulating PKCε by VIP or PMA increases membrane insertion and activity of WT- and F508del-CFTR.