The effect of nasal douching by hypertonic 2.3 per cent sea water with algae extracts on the concentration of epidermal growth factor, transforming growth factor-α and interleukin-8 in nasal secretions of patients with nasal polyposis following endoscopic surgical treatment.

OBJECTIVE: To investigate epidermal growth factor, transforming growth factor-α and interleukin-8 production in nasal mucosa irrigated with hypertonic 2.3 per cent solution with algae extracts, in comparison to 0.9 per cent NaCl during the first two weeks after surgery for nasal polyposis, in relation to symptoms and local findings. METHODS: This prospective study included 20 nasal polyposis patients postoperatively irrigated with hypertonic solution and 20 nasal polyposis patients postoperatively irrigated with isotonic solution. We evaluated nasal symptom score, endoscopic score and mediator levels in nasal secretions before and after irrigation. RESULTS: Following treatment, nasal symptom score and endoscopic score were significantly lower in the hypertonic solution group (p = 0.023; p < 0.001, respectively). The increase in the epidermal growth factor and the decrease in the transforming growth factor-α and interleukin-8 concentration were higher in the hypertonic group (p < 0.001 for all mediators). CONCLUSION: Irrigation with a hypertonic solution was found to be more effective than an isotonic solution in nasal mucosa reparation.

Activin-A overexpression in the murine lung causes pathology that simulates acute respiratory distress syndrome.

RATIONALE: Activin-A is up-regulated in various respiratory disorders. However, its precise role in pulmonary pathophysiology has not been adequately substantiated in vivo. OBJECTIVES: To investigate in vivo the consequences of dysregulated Activin-A expression in the lung and identify key Activin-A-induced processes that contribute to respiratory pathology. METHODS: Activin-A was ectopically expressed in murine lung, and functional, structural, and molecular alterations were extensively analyzed. The validity of Activin-A as a therapeutic target was demonstrated in animals overexpressing Activin-A or treated with intratracheal instillation of LPS. Relevancy to human pathology was substantiated by demonstrating high Activin-A levels in bronchoalveolar lavage (BAL) samples from patients with acute respiratory distress syndrome (ARDS). MEASUREMENTS AND MAIN RESULTS: Overexpression of Activin-A in mouse airways caused pulmonary pathology reminiscent of acute lung injury (ALI)/ARDS. Activin-A triggered a lasting inflammatory response characterized by acute alveolar cell death and hyaline membrane formation, sustained up-regulation of high-mobility group box 1, development of systemic hypercoagulant state, reduction of surfactant proteins SpC, SpB, and SpA, decline of lung compliance, transient fibrosis, and eventually emphysema. Therapeutic neutralization of Activin-A attenuated the ALI/ARDS-like pathology induced either by ectopic expression of Activin-A or by intratracheal instillation of LPS. In line with the similarity of the Activin-A-induced phenotype to human ARDS, selective up-regulation of Activin-A was found in BAL of patients with ARDS. CONCLUSIONS: Our studies demonstrate for the first time in vivo the pathogenic consequences of deregulated Activin-A expression in the lung, document novel aspects of Activin-A biology that provide mechanistic explanation for the observed phenotype, link Activin-A to ALI/ARDS pathophysiology, and provide the rationale for therapeutic targeting of Activin-A in these disorders.

Integrin-linked kinase (ILK) in pulmonary fibrosis.

Pulmonary fibrosis is a common feature of a large group of lung diseases. The molecular mechanisms underlying pulmonary fibrosis and the key macromolecules involved are not fully understood yet. In an effort to better understand aspects of pulmonary fibrosis, the established bleomycin injection model in mice was used and the focus of the present study was on integrin-linked kinase (ILK) expression. ILK is an intracellular protein involved in the regulation of integrin-mediated processes. In fibrosis, ILK has been examined in the kidney and in the liver where it mediates epithelial to mesenchymal transition (EMT) and hepatic stellate cell activation, respectively. However, information on ILK's involvement in lung fibrosis is missing. In order to examine ILK's role in pulmonary fibrosis, we used both an in vivo and an in vitro approach. In vivo, the bleomycin model was used in order to examine ILK's expression and localization in the fibrotic lung. In vitro, transforming growth factor-ß1 was used to induce fibrotic characteristics and EMT in alveolar epithelial cells. ILK's role in alveolar EMT was studied by siRNA. Our results demonstrate that in the animal model used, ILK exhibits a decrease in expression at early stages of the fibrotic process and that a specific subset of fibroblasts is expressing ILK. The in vitro experiments suggested that ILK is not directly involved in E-cadherin downregulation and initiation of EMT (as is the case in renal fibrosis) but is involved in upregulation of vimentin. These results suggest that ILK is involved in lung fibrosis in a tissue-specific manner and raise the possibility to use it as a specific therapeutic target for lung fibrosis in the future.

Isolation and characterization of human anti-acetylcholine receptor monoclonal antibodies from transgenic mice expressing human immunoglobulin loci.

The isolation of human antibodies against muscle acetylcholine receptor (AChR), the autoantigen involved in myasthenia gravis (MG), is important for the development of therapeutically useful reagents. Monovalent antibody fragments from monoclonal antibodies against the main immunogenic region (MIR) of AChR protect the receptor from the destructive activity of MG autoantibodies. Human anti-AChR alpha-subunit antibody fragments with therapeutic potential have been isolated using phage display antibody libraries. An alternative approach for obtaining human mAb has been provided by the development of humanized mice. In this report, we show that immunization of transgenic mouse strains with the extracellular domain of the human AChR alpha-subunit results in antibody responses and isolation of hybridomas producing human mAb. Four specific IgM mAb were isolated and analyzed. mAb170 recognized the native receptor the best and was capable of inducing AChR antigenic modulation, suggesting its specificity for a pathogenic epitope. Moreover, the recombinant antigen-binding (Fab) fragment of this mAb competed with an anti-MIR mAb, revealing that its antigenic determinant lies in or near the MIR. Finally, Fab170 was able to compete with MG autoantibodies and protect the AChR against antigenic modulation induced by MG sera. This approach will be useful for isolating additional mAb with therapeutic potential against the other AChR subunits.