Peptides as surface coatings of nanoparticles that penetrate human cystic fibrosis sputum and uniformly distribute in vivo following pulmonary delivery.

Therapeutic delivery of drug and gene delivery systems have to traverse multiple biological barriers to achieve efficacy. Mucosal administration, such as pulmonary delivery in cystic fibrosis (CF) disease, remains a significant challenge due to concentrated viscoelastic mucus, which prevents drugs and particles from penetrating the mucus barrier. To address this problem, we used combinatorial peptide-presenting phage libraries and next-generation sequencing (NGS) to identify hydrophilic, net-neutral charged peptide coatings that enable penetration through human CF mucus ex vivo with ~600-fold better penetration than control, improve uptake into lung epithelial cells compared to uncoated or PEGylated-nanoparticles, and exhibit enhanced uniform distribution and retention in the mouse lung airways. These peptide coatings address multiple delivery barriers and effectively serve as excellent alternatives to standard PEG surface chemistries to achieve mucus penetration and address some of the challenges encountered using these chemistries. This biomolecule-based strategy can address multiple delivery barriers and hold promise to advance efficacy of therapeutics for diseases like CF.

Respiratory syncytial virus infection in a murine model of cystic fibrosis.

Viral respiratory infections play an important role in the development and progression of pulmonary disease in cystic fibrosis (CF). The CF mouse model provides a tool to examine the relationship between the cystic fibrosis transmembrane conductance regulator (CFTR) defect and lung disease. This work investigates the cellular response to a common viral pathogen, respiratory syncytial virus (RSV) in the lung of CF mice. RSV was administered by intranasal inoculation of CFTR(tm1Unc)-Tg(FABPCFTR)1Jaw/J (CFTR-/-) and control mice. At day 5 post infection, viral titers, bronchoalveolar fluid nitrate levels (BALF) cell and differential counts, histology and studies on airway mechanics were performed. CFTR-/- mice had an impaired ability to clear RSV. This was associated with an exaggerated inflammatory response (increased lymphocytes and neutrophils) in BALF of RSV-infected CFTR-/- mice and a decreased ability to generate nitric oxide (NO) (measured as BAL nitrate). Lung histopathology of RSV-infected CFTR-/- mice demonstrated increased inflammation compared to RSV (-) CFTR-/- and control mice (regardless of RSV treatment). The airway response to methacholine was increased by RSV infection in CF mice when compared to controls. The CFTR-/- mouse exhibits an aberrant response to RSV infection. This model should be useful in providing further mechanistic information on the biology of respiratory viruses in mammalian models, and provide new insights into the pathogenesis of airway inflammation in patients with CF.

Role of cysteinyl leukotrienes in airway inflammation and responsiveness following RSV infection in BALB/c mice.

Cysteinyl leukotrienes (CysLTs) contribute to the development of airway obstruction and inflammation in asthma; however little information is available on the role of these molecules in the pathophysiology of respiratory syncytial virus (RSV) bronchiolitis. This study was designed to evaluate the effects of RSV infection on CysLTs production in a well-established mouse infection model. Furthermore, we assessed the effect of anti-inflammatory agents (a leukotriene receptor antagonist, MK-571, and dexamethasone) on the functional and immune changes induced by RSV infection. Six to 8-wk-old BALB/c mice were infected with human RSV (strain A2). Measurements of airway function were performed using whole body plethysmography. Lung inflammation was assessed by cell counts, measurement of cytokines and CysLTs in bronchoalveolar lavage fluid (BALF) in the absence and presence of treatment with MK-571 or dexamethasone. RSV infection produced a marked increase in CysLTs in the BALF and lung tissue, recruitment of neutrophils and lymphocytes into the airways, increased IFN-gamma levels and airway hyperresponsiveness (AHR). Treatment with MK-571 decreased RSV-induced AHR without affecting the cellular and inflammatory responses to RSV. Dexamethasone decreased AHR and markedly reduced the recruitment of inflammatory cells and production of IFN-gamma. Our findings suggest CysLTs play an important role in the pathogenesis of RSV-induced airway dysfunction. Treatment with MK-571 decreases RSV-induced AHR but does not appear to alter the lung inflammatory responses to RSV. In contrast, dexamethasone decreases RSV-induced AHR but interferes with recruitment of inflammatory cells, resulting in decreased Th1 cytokines (a potentially Th2-prone environment) in this model. These studies support recent reports on the beneficial effects of CysLT receptor antagonist in human trials and provide a model for investigating the role of CysLTs in RSV bronchiolitis.

Successful treatment of bronchiolitis obliterans in a bone marrow transplant patient with tumor necrosis factor-alpha blockade.

Bronchiolitis obliterans (BO) in children is a rare, inflammatory/fibrosing process involving the small airways that often results in progressive, irreversible obstructive pulmonary disease. Because treatment has focused mainly on supportive care and generally unsuccessful immunosuppression, children with BO experience significant morbidity and mortality. We report a case of biopsy-proven BO after bone marrow transplantation in a child who, after failed corticosteroid therapy, was treated with infliximab, a monoclonal antibody with binding specificity for human tumor necrosis factor-alpha. With initiation of treatment, her pulmonary symptoms and radiographic and spirometric evidence of BO resolved. Nine months later, she remains asymptomatic and shows no evidence of pulmonary decompensation. This case illustrates a successful treatment of BO with selective tumor necrosis factor-alpha blockade.

Pulmonary capillaritis in children: a review of eight cases with comparison to other alveolar hemorrhage syndromes.

OBJECTIVE: To review clinical, laboratory, and outcome characteristics of children diagnosed with pulmonary capillaritis (PC), a small-vessel vasculitis, presenting as diffuse alveolar hemorrhage (DAH), and to compare these findings with those for children with other alveolar hemorrhage syndromes. STUDY DESIGN: A retrospective chart review of patients who underwent a lung biopsy because of a clinical suggestion of pulmonary hemorrhage. RESULTS: PC was identified in 8 of 23 patients. In these patients, cough, crackles, and hypoxia were common. Alveolar infiltrates on radiography and anemia were present in 7 of 8 cases. Serologic evidence of a systemic vasculitis was present in 50% of patients. High-dose corticosteroids proved effective in controlling alveolar hemorrhage in all cases. There were no presenting signs or symptoms that could differentiate patients with PC from those with non-immune-mediated alveolar hemorrhage. In general, patients with PC had a lower hematocrit and higher erythrocyte sedimentation rate (ESR). CONCLUSION: Children presenting with lower respiratory tract symptoms, chest x-ray abnormalities, and anemia should undergo evaluation for PC, as early initiation of immunosuppression can be lifesaving and organ sparing. No clinical signs to differentiate immune and non-immune-mediated alveolar hemorrhage were evident in this study.