Introduction. Mediterranean diet (MD) has been proposed as a dietary pattern model to prevent or delay brain dysfunction by gut manipulation. Alterations of colonic environment including microbial population and derived metabolites have been associated with neurological alterations explained by gut-brain connection. Differences in metabolic profile between healthy and Alzheimer disease (AD) patients may offer the possibility to identify potential target to treat or delay the onset of the disease. The aim of this study was to identify possible metabolic alterations in the colon environment of AD patients compared with matched controls in the context of a MD. Material and methods. Healthy subjects (n=19) and AD patients (n=25) of both sexes, between 55-75 y from La Rioja, Spain, participated in this observational study. Data concerning dietary habits were obtained during personal interview and processed to calculate MD adherence score and nutrients intake. Plasmatic and fecal short chain fatty acids (SCFA) were determined by GC-MS/MS and fecal biomarkers of intestinal inflammation (IL-1β, TNF-α, calprotectin) were quantified by ELISA. Results. Dietary data and intestinal metabolites are reported in control and AD volunteers. Despite similar MD score, the consumption of animal proteins (p=0.048), fruits (p=0.006) and phenol flavones (p=0.013) were different between groups. Feces of controls were enriched in caproic acid (p=0.008) whereas propionic acid (p=0.017) was more abundant in fecal samples of AD patients. In plasma, isovaleric acid was higher in the control group (p=0.041). Regarding the biomarkers of intestinal inflammation, we observed that IL-1β was increased in feces of control volunteers (p=0.008). Correlations among SCFA, IL-1β and dietary parameters were also evaluated. Conclusions. These initial data suggest difference in microbial metabolism among healthy and AD patients which could be considered as possible participants in the gut-brain axis communication.

Trabajo presentado en la Reunión Conjunta: LXVII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC); LXX Reunión Anual de la Sociedad Argentina de Inmunología (SAI) & 3er Congreso Franco-Argentino de Inmunología (FAIC); Reunión Anual 2022 de la Sociedad argentina de Fisiología (SAFIS), celebrada en Buenos Aires (Argentina), del 16 al 19 de noviembre de 2022