[Contribution of hypoxia in pulmonary tissue remodeling in asthmatic processes]. / Contribución de la hipoxia en la remodelación del tejido pulmonar en procesos asmáticos.

Asthma is a chronic airway inflammatory disease that is associated with pulmonary remodelling of respiratory tissue. During asthma, lung structure changes due to persistent inflammation and causes obstruction of the air flow, which leads to a paradoxical hypoxic condition in the affected pulmonary tissue. Angiogenesis, which is one of the main components of the remodelling process, is mainly regulated by the vascular endothelial growth factor (VEGF), although other less influential factors are also involved. It is known that VEGF is up-regulated by hypoxia inducible factor 1 (HIF-1) during hypoxia. The transcription factor HIF-1 is a dimeric protein composed of two subunits: HIF-1alpha (inducible by hypoxia) and HIF-1beta (constitutive). HIF-1 activates the transcription of genes during hypoxia by translocating to the nucleus and binding to hypoxia response elements (HREs) on the promoter regions of target genes. Recently the expression of HIF has been documented during angiogenesis in lung remodelling during asthma, thus suggesting that it may play a role in this process. The objective of this review is to give to the reader an overview of the literature in hypoxia and its role in remodelling and the pathogenesis of asthma.

Therapeutic efficacy of an E coli strain carrying an ovalbumin allergenic peptide as a fused protein to OMPC in a murine model of allergic airway inflammation.

An Escherichia coli strain expressing the ovalbumin (OVA) 323-329 allergenic peptide on the bacterial surface was evaluated for its ability to reduce the lung inflammatory response in mice allergic to OVA. BALB/c mice were rendered allergic by means of two intraperitoneal injections of OVA suspended in alum 5 days apart, and one intratracheal boost 1 week later. The mice were then treated with two intranasal, 1 week apart, doses of 4x10(9) E. coli-UH302 transformed with plasmids pST13 or pST13-OVA(323-339), which bear the OmpC porin from Salmonella enterica serovar Typhi or the OmpC with the OVA allergenic 323-339 amino acid sequence inserted in the external loop 5. The allergic inflammatory reaction was evaluated on day 31, finding that mice treated with E. coli-UH302-pST13-OVA reduced four to seven times perivascular and peribronchial infiltrates, mucus production, goblet cell hyperplasia and eosinophils when compared with mice treated with E. coli-UH302-pST13 or saline solution. These results were consistent with a significant decrease of IL-5 mRNA and induction of IFN-gamma mRNA in cells from bronchio-alveolar lavages (BAL). Specific serum IgE anti-OVA was also reduced, although the decrease did not reach statistical significance. These results demonstrate that the bacterial live vector bearing an allergenic peptide successfully moderated two important components of allergy, pulmonary inflammation and mucus overproduction.