Associations between respiratory symptoms, lung function and gastro-oesophageal reflux symptoms in a population-based birth cohort

BACKGROUND: Several studies have reported an association between asthma and gastro-oesophageal reflux, but it is unclear which condition develops first. The role of obesity in mediating this association is also unclear. We explored the associations between respiratory symptoms, lung function, and gastro-oesophageal reflux symptoms in a birth cohort of approximately 1000 individuals. METHODS: Information on respiratory symptoms, asthma, atopy, lung function and airway responsiveness was obtained at multiple assessments from childhood to adulthood in an unselected birth cohort of 1037 individuals followed to age 26. Symptoms of gastro-oesophageal reflux and irritable bowel syndrome were recorded at age 26. RESULTS: Heartburn and acid regurgitation symptoms that were at least "moderately bothersome" at age 26 were significantly associated with asthma (odds ratio = 3.2; 95% confidence interval = 1.6–6.4), wheeze (OR = 3.5; 95% CI = 1.7–7.2), and nocturnal cough (OR = 4.3; 95% CI = 2.1–8.7) independently of body mass index. In women reflux symptoms were also associated with airflow obstruction and a bronchodilator response to salbutamol. Persistent wheezing since childhood, persistence of asthma since teenage years, and airway hyperresponsiveness since age 11 were associated with a significantly increased risk of heartburn and acid regurgitation at age 26. There was no association between irritable bowel syndrome and respiratory symptoms. CONCLUSION: Reflux symptoms are associated with respiratory symptoms in young adults independently of body mass index. The mechanism of these associations remains unclear

Protector mechanisms of the association between gastroesophageal reflux disease and asthma: experimental study in rats Mecanismos protetores: doença do refluxo gastroesofágico e asma. Estudo experimental em ratos

BACKGROUND: It is well known the association between gastroesophageal reflux disease and asthma. The hyperreactivity of the airways is a characteristic of an asthmatic. Many studies associate the increase of the airways reactivity with gastroesophageal reflux disease. AIM: In this study we have evaluated the effect of the intraluminal exposition to gastric juice of trachea on the reactivity to methacholine from rats submitted to a pulmonary allergic inflammation. METHODS: Group of rats were sensitized and challenged with ovalbumin. After 24 hours the animals were sacrificed, and their tracheae were removed to be cultured with gastric juice. The gastric juice was obtained from a donor rat. Subsequently the segments were placed into plastic plates with RPMI-1640 for incubation, under suitable atmosphere and time. After the period of incubation the segments were put into chambers for the analysis of the contractile response to methacholine. RESULTS: We observed reduction in the contractile response of trachea cultured with gastric juice from allergic rats. This result was confirmed by the pharmacological treatments with compound 48/80 and dissodium cromoglicate (mast cells blockade), L-NAME (nitric oxide inhibitor, NO), capsaicin (neuropeptides depletion) and indomethacin (ciclooxigenase inhibitor). CONCLUSIONS: Our results highlight to the existence of a complex interaction between pulmonary allergy and gastric juice in the airways. The involvement of the non-adrenergic non-cholinergic system, NO, prostanoids and mast cells are directly related to this interaction. We suggest that the reduced contractile response observed in vitro may represent a protector mechanism of the airways. Despite its presence in the human body it can not be observed due to the predominant effects of excitatory the non-adrenergic non-cholinergic system.<br>RACIONAL: É bem estabelecida a relação entre a doença do refluxo gastroesofágico e a asma. A hiperreatividade das vias aéreas é uma das características que o indivíduo asmático desenvolve e diversos estudos associam o aumento da reatividade das vias aéreas com o refluxo gastroesofágico. OBJETIVO: Avaliar a reatividade à metacolina de traquéia exposta intraluminalmente ao suco gástrico de ratos submetidos a inflamação alérgica pulmonar. MÉTODOS: Grupos de ratos foram sensibilizados e broncoprovocados com ovoalbumina. Após 24 horas, os animais foram sacrificados e a traquéia removida para preenchimento de seu lúmen com suco gástrico obtido de um animal doador. A seguir, os segmentos foram colocados em placas plásticas com RPMI-1640 e mantidos em estufa por 3 horas em condições ambientais adequadas. Após o tempo de incubação, os fragmentos foram montados em cubas de vidro para órgão isolado para registro isométrico de contração, através da construção de curvas concentração-efeito à metacolina. RESULTADOS: Observou-se redução da resposta contrátil em traquéia exposta ao suco gástrico proveniente de ratos alérgicos. Os tratamentos farmacológicos com composto 48/80 e cromoglicato de sódio (bloqueio de mastócitos), L-NAME (inibidor de óxido nítrico, NO), capsaicina (depleção de neuropeptídios) e indometacina (inibidor da ciclooxigenase) corroboraram esta observação. CONCLUSÕES: Os resultados apontam para a existência de complexa interação entre a alergia pulmonar e o suco gástrico nas vias aéreas, com o envolvimento do sistema não-adrenérgico não-colinérgico, NO, prostanóides e mastócitos. À luz das evidências in vivo sobre a hiperreatividade das vias aéreas na associação asma e refluxo gastroesofágico, sugere-se que a reduzida resposta contrátil detectada in vitro pode representar um mecanismo protetor das vias aéreas. A despeito de sua presença, esta redução pode não ser observada in vivo devido à proeminência dos efeitos do sistema não-adrenérgico não-colinérgico excitatório