Inhalation of concentrated PM2.5 from Mexico City acts as an adjuvant in a guinea pig model of allergic asthma.

Exposure to Particulate Matter (PM) could function as an adjuvant depending on the city of origin in mice allergic asthma models. Therefore, our aim was to determine whether inhalation of fine particles (PM2.5) from Mexico City could act as an adjuvant inducing allergic sensitization and/or worsening the asthmatic response in guinea pig, as a suitable model of human asthma. Experimental groups were Non-Sensitized (NS group), sensitized with Ovalbumin (OVA) plus Aluminum hydroxide (Al(OH)3) as adjuvant (S + Adj group), and sensitized (OVA) without adjuvant (S group). All the animals were exposed to Filtered Air (FA) or concentrated PM2.5 (5 h/daily/3 days), employing an aerosol concentrator system, PM2.5 composition was characterized. Lung function was evaluated by barometric plethysmography (Penh index). Inflammatory cells present in bronchoalveolar lavage were counted as well as OVA-specific IgG1 and IgE were determined by ELISA assay. Our results showed in sensitized animals without Al(OH)3, that the PM2.5 exposure (609 ± 12.73 µg/m3) acted as an adjuvant, triggering OVA-specific IgG1 and IgE concentration. Penh index increased ∼9-fold after OVA challenge in adjuvant-sensitized animals as well as in S + PM2.5 group (∼6-fold), meanwhile NS + FA and S + FA lacked response. S + Adj + PM2.5 group showed an increase significantly of eosinophils and neutrophils in bronchoalveolar lavage. PM2.5 composition was made up of inorganic elements and Polycyclic Aromatic Hydrocarbons, as well as endotoxins and ß-glucan, all these components could act as adjuvant. Our study demonstrated that acute inhalation of PM2.5 acted as an adjuvant, similar to the aluminum hydroxide effect, triggering allergic asthma in a guinea pig model. Furthermore, in sensitized animals with aluminum hydroxide an enhancing influence of PM2.5 exposure was observed as specific-hyperresponsiveness to OVA challenge (quickly response) and eosinophilic and neutrophilic airway inflammation. Fine particles from Mexico City is a complex mix, which play a significant role as adjuvant in allergic asthma.

Albúmina humana y albúmina de rata como contaminantes ambientales en la Ciudad de México / Human albumin and rat albumin as pollutants in Mexico city

El deterioro de la atmósfera, por elementos nocivos, se ha identificado como causa de alteraciones en la salud, sobre todo de tipo respiratorio. Existen elementos en la atmósfera que aún se desconocen. Con objeto de definir mejor la composición atmosférica, se determinó la presencia de albúmina humana(AH) y albúmina de rata (AR) en 117 extractos de filtros ambientales por inmunoenzimoensayo con anticuerpos específicos contra cada antígeno. Se encontró, que existen cantidades detectables de AH(2-200 ug/mL), en el 44.4 por ciento de los filtros, y de AR en el 20.5 por ciento; sólo el 14.5 por ciento fue positivo para ambas proteínas. Nos podría sorprender la presencia de estas proteínas en el aire, pero existen y ésto nos sugeriría que la composición protéica de la atmósfera que respiramos puede ser más compleja de lo que se sospecha, planteandose así un reto mayor para identificar la causa de los padecimientos respiratorios