Melissa A. Rosenfeld

In vivo transfer of the human cystic fibrosis transmembrane conductance regulator gene to the airway epithelium

Direct transfer of the normal cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene to airway epithelium was evaluated using a replication-deficient recombinant adenovirus (Ad) vector containing normal human CFTR cDNA (Ad-CFTR). In vitro Ad-CFTR-infected CFPAC-1 CF epithelial cells expressed human CFTR mRNA and protein and demonstrated correction of defective cAMP-mediated Cl- permeability. Two days after in vivo intratracheal introduction of Ad-CFTR in cotton rats, in situ analysis demonstrated human CFTR gene expression in lung epithelium. PCR amplification of reverse transcribed lung RNA demonstrated human CFTR transcripts derived from Ad-CFTR, and Northern analysis of lung RNA revealed human CFTR transcripts for up to 6 weeks. Human CFTR protein was detected in epithelial cells using anti-human CFTR antibody 11-14 days after infection. While the safety and effectiveness remain to be demonstrated, these observations suggest the feasibility of in vivo CFTR gene transfer as therapy for the pulmonary manifestations of CF.

Administration of an adenovirus containing the human CFTR cDNA to the respiratory tract of individuals with cystic fibrosis.

We have administered a recombinant adenovirus vector (AdCFTR) containing the normal human CFTR cDNA to the nasal and bronchial epithelium of four individuals with cystic fibrosis (CF). We show that this vector can express the CFTR cDNA in the CF respiratory epithelium in vivo. With doses up to 2 × 109 pfu, there was no recombination/complementation or shedding of the vector or rise of neutralizing antibody titres. At 2 × 109 pfu, a transient systemic and pulmonary syndrome was observed, possibly mediated by interleukin-6. Follow-up at 6–12 months demonstrated no long term adverse effects. Thus, it is feasible to use an adenovirus vector to transfer and express the CFTR cDNA in the respiratory epithelium of individuals with CF. Correction of the CF phenotype of the airway epithelium might be achieved with this strategy.

Diversity of airway epithelial cell targets for in vivo recombinant adenovirus-mediated gene transfer.

A variety of pulmonary disorders, including cystic fibrosis, are potentially amenable to treatment in which a therapeutic gene is directly transferred to the bronchial epithelium. This is difficult to accomplish because the majority of airway epithelial cells replicate slowly and/or are terminally differentiated. Adenovirus vectors may circumvent this problem, since they do not require target cell proliferation to express exogenous genes. To evaluate the diversity of airway epithelial cell targets for in vivo adenovirus-directed gene transfer, a replication deficient recombinant adenovirus containing the Escherichia coli lacZ (beta-galactosidase [beta-gal]) gene (Ad.RSV beta gal) was used to infect lungs of cotton rats. In contrast to uninfected animals, intratracheal Ad.RSV beta gal administration resulted in beta-gal activity in lung lysate and cytochemical staining in all cell types forming the airway epithelium. The expression of the exogenous gene was dose-dependent, and the distribution of the beta-gal positive airway epithelial cells in Ad.RSV beta gal-infected animals was similar to the normal cell differential of the control animals. Thus, a replication deficient recombinant adenovirus can transfer an exogenous gene to all major categories of airway epithelial cells in vivo, suggesting that adenovirus vectors may be an efficient strategy for in vivo gene transfer in airway disorders such as cystic fibrosis.

A Report of Familial Carotid Body Tumors and Multiple Extra-Adrenal Pheochromocytomas

A case of familial carotid body tumors and multiple extra-adrenal pheochromocytomas is reported. The carotid body tumors, resected previously, were bilateral and associated with 4 intra-abdominal extra-adrenal pheochromocytomas. Magnetic resonance imaging was far superior to computerized tomography and 131iodine-metaiodobenzylguanidine in visualizing the intra-abdominal lesions, and may soon become the imaging technique of choice in the evaluation of patients with suspected pheochromocytoma.