title: Molecular composition of the alveolar lining fluid in the aging lung.
abstract: As we age, there is an increased risk for the development of pulmonary diseases, including infections, but few studies have considered changes in lung surfactant and components of the innate immune system as contributing factors to the increased susceptibility of the elderly to succumb to infections. We and others have demonstrated that human alveolar lining fluid (ALF) components, such as surfactant protein (SP)-A, SP-D, complement protein C3, and alveolar hydrolases, play a significant innate immune role in controlling microbial infections. However, there is a lack of information regarding the effect of increasing age on the level and function of ALF components in the lung. Here we addressed this gap in knowledge by determining the levels of ALF components in the aging lung that are important in controlling infection. Our findings demonstrate that pro-inflammatory cytokines, surfactant proteins and lipids, and complement components are significantly altered in the aged lung in both mice and humans. Further, we show that the aging lung is a relatively oxidized environment. Our study provides new information on how the pulmonary environment in old age can potentially modify mucosal immune responses, thereby impacting pulmonary infections and other pulmonary diseases in the elderly population.
authors.affiliation: Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, USA.
authors.forename: Juan I
authors.initials: JI
authors.lastname: Moliva
authors.forename: Murugesan V S
authors.initials: MV
authors.lastname: Rajaram
authors.forename: Sabeen
authors.initials: S
authors.lastname: Sidiki
authors.forename: Smitha J
authors.initials: SJ
authors.lastname: Sasindran
authors.forename: Evelyn
authors.initials: E
authors.lastname: Guirado
authors.forename: Xueliang Jeff
authors.initials: XJ
authors.lastname: Pan
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Wang
authors.forename: Patrick
authors.initials: P
authors.lastname: Ross
authors.forename: William P
authors.initials: WP
authors.lastname: Lafuse
authors.forename: Larry S
authors.initials: LS
authors.lastname: Schlesinger
authors.forename: Joanne
authors.initials: J
authors.lastname: Turner
authors.forename: Jordi B
authors.initials: JB
authors.lastname: Torrelles
mesh_terms: D000328:Adult; D000375:Aging / Q000378:metabolism*; D000818:Animals; D005260:Female; D006801:Humans; D006867:Hydrolases / Q000378:metabolism; D008168:Lung / Q000378:metabolism*; D008297:Male; D051379:Mice; D018384:Oxidative Stress; D011650:Pulmonary Alveoli / Q000378:metabolism*; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism*
chemical_list: D037662:Pulmonary Surfactant-Associated Protein A; D006867:Hydrolases