Human Neutrophils Couple Nitric Oxide Production and Extracellular Traps Formation in Allergic Asthma.

RATIONALE: Nitric oxide (NO) is elevated in the airways and serum of allergic asthmatic patients, suggesting an important role in asthma. NO production has been widely attributed to the canonical inducible nitric oxide synthase (iNOS). Much effort has been made to inhibit this enzyme with two outcomes: no asthma improvement; and partial NO reduction, suggesting the involvement of an iNOS-independent source. OBJECTIVES: Neutrophils produce NO under inflammatory conditions and their role in asthma has been overlooked. The present study analyzes their possible role as source of NO. METHODS: Our hypothesis was tested in 99 allergic patients with intermittent bronchial asthma and 26 healthy donors. NO production by blood and sputum neutrophils in response to allergens, anti-IgE, and anti-IgE receptors Abs was assessed by Griess, flow cytometry and confocal microscopy. Extracellular traps (ETs) formation, as a possible consequence of NO production, was quantified by western blot and confocal microscopy, and reactive oxygen species by luminol-enhanced chemiluminescence. RESULTS: Among blood and sputum granulocytes from allergic asthmatic patients, only neutrophils, produce NO by an IgE-dependent mechanism. This production is independent of NOS, but dependent on a reaction between L-arginine and reactive oxygen species from NOX2. NO and ETosis are induced in parallel, and NO amplifies ETs formation, which is a key mediator in asthma. CONCLUSIONS: Our findings reveal a novel role of neutrophils as the unique allergen/IgE-dependent NO source in allergic asthma enhancing ETs formation. These results suggest that NO produced by neutrophils needs further consideration in the treatment of allergic asthma.

Regulation and directed inhibition of ECP production by human neutrophils.

Background: Neutrophils are involved in the pathophysiology of allergic asthma, where the Eosinophil Cationic Protein (ECP) is a critical inflammatory mediator. Although ECP production is attributed to eosinophils, we reported that ECP is also present in neutrophils from allergic patients where, in contrast to eosinophils, it is produced in an IgE-dependent manner. Given the key role of ECP in asthma, we investigated the molecular mechanisms involved in ECP production as well as the effects induced by agonists and widely used clinical approaches. We also analyzed the correlation between ECP production and lung function. Methods: Neutrophils from allergic asthmatic patients were challenged with allergens, alone or in combination with cytokines, in the presence of cell-signaling inhibitors and clinical drugs. We analyzed ECP levels by ELISA and confocal microscopy. Lung function was assessed by spirometry. Results: IgE-mediated ECP release is dependent on phosphoinositide 3-kinase, the extracellular signal-regulated kinase (ERK1/2) and the production of reactive oxygen species by NADPH-oxidase. Calcineurin phosphatase and the transcription factor NFAT are also involved. ECP release is enhanced by the cytokines interleukin (IL)-5 and granulocyte macrophage-colony stimulating factor, and inhibited by interferon-γ, IL-10, clinical drugs (formoterol, tiotropium and budesonide) and allergen-specific IT. We also found an inverse correlation between asthma severity and ECP levels. Conclusions: Our results suggest the molecular pathways involved in ECP production and potential therapeutic targets. We also provide a new method to evaluate disease severity in asthmatic patients based on the quantification of in vitro ECP production by peripheral neutrophils.

Contaminación enteroparasitaria de intercomunicadores en edificios de Barquisimeto y Cabudare, Venezuela / Enteroparites contamination of intercoms in buildings of Barquisimeto and Cabudare, Venezuela

Resumen Introducción. La falta de estudios en intercomunicadores como medios de propagación de enteroparásitos en Venezuela, motivó el presente estudio. Metodología. Se frotó el intercomunicador tres veces con un hisopo impregnado con solución salina 0,85% (SSI), resuspendiéndolo en un tubo con 10 ml de SSI, el cual se centrifugó a 3000 rpm por 10 minutos para luego observar el sedimente al microscopio. Resultados. El 65% de las muestras estuvieron contaminadas, encontrando 10 taxones de enteroparásitos, a saber: Blastocystis sp (49% del total de muestras examinadas), Endolimax nana (36%), lodamoeba butschlii (8%), Giardia lamblia (7%), Entamoeba coli (4%), Chilomastix mesnili (2%), Entamoeba hartmanni (2%), Trichuris trichiura (2%), Hymenolepis nana (2%) y Taenia sp (1%). Discusión. La diversidad de parásitos encontrados y su abundancia, se corresponden con lo reportado en poblaciones de la misma zona. Conclusión. La falta de higiene en la mayoría de los intercomunicadores facilitan el potencial de estos para transmitir los parásitos endémicos del estado Lara.

Abstract Introduction. The lack of studies in intercoms as means of propagation of enteroparasites in Venezuela, motivated the present study. Methodology. The intercom was rubbed three times with a swab impregnated with 0.85% saline solution (SSI), resuspending it in a tube with 10 ml of SSI, which was centrifuged at 3000 rpm for 10 minutes to then observe the pellet under a microscope. Results. 65% of the samples were contaminated, finding 10 taxa of enteroparasites, namely: Blastocystis sp (49% of the samples examined), Endolimax nana (36%), Iodamoeba butschlii (8%), Giardia lamblia (7%), Entamoeba coli (4%), Chilomastix mesnili (2%), Entamoeba hartmanni (2%), Trichuris trichiura (2%), Hymenolepis nana (2%) and Taenia sp (1%). Discussion. The diversity of parasites found and their abundance correspond to that reported in populations of the same area. Conclusion. The lack of hygiene of most of the intercoms facilitates the potential of these to transmit the endemic parasites of the Lara State.