Anales RANF

P.102 SIGNIFICANCE OF ADENOSINE A 2A RECEPTORS IN THE COMMENSAL-PATHOGEN SWITCH IN THE ELDERLY GUT L.Rodrigues 1,2 , I.Miranda 3 , G.Andrade 4 , M.Mota 1,2 , L.Cortes 1 , A.Rodrigues 3 , R.A. Cunha 1,2 , T. Gonçalves 1,2 1 CNC-Center for Neurosciences and Cell Biology,Coimbra, Portugal; 2 Faculty of Medicine, University of Coimbra, Portugal ; 3 Faculty of Medicine-University of Porto;CINTESIS, Porto, Portugal; 4 Federal University of Ceará,Fortaleza, Brazil. Immunosenescence and inflammaging of the elderly is a public health issue, associated with increased morbidity and mortality due to infections and chronic inflammatory gut diseases. 1,2 The adenosine A 2A receptor (A 2A R) contributes to fine-tuning inflammatory and immune responses, prompting an efficient elimination of threats while minimizing tissue damage. 3 We studied the gut A 2A R distribution/density in an in vivo mice model of aged, adult and young individuals; assessed the relative intestinal over-colonization by Candida albicans , a gut commensal that can turn into an aggressive agent of opportunistic infections 1,2 , and the correlation between this, tissue damage and gut microbiota diversity. We showed that elderly mice are more prone to over-colonization by C.albicans than adults and young. This seems to be related with higher growth rate in intestinal lumen, independent of gut tissues invasion, with higher inflammation of the elderly gut. These mice have a higher stomach colonization and increased yeast-to-hypha transition, a virulent trait. When compared with young and adults, aged mice have lower gut A 2A R density and C.albicans overgrowth failed to increase it. 4 These results indicate that aged mice have lower ability to cope with inflammation due to C.albicans over-colonization and phenotypic switch, related with the inability to adaptively adjust A 2A R density. In conclusion, gut over-colonization/dysbiosis control and microbiota homeostasis is likely to be regulated by the purinergic system, particularly A 2A R. 1) Bischoff. Curr Opin Clin Nutr Metab Care.2016;19:26. 2) Köhler et al. Microbiol Spectrum.2017;5:FUNK-0014. 3) Hasko et al. Nat Rev Drug Discov.2008;7:759. 4) Rodrigues et al. Oncotarget.2016;7:62862.