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Angiotensin (1–7) delivered orally via probiotic, but not subcutaneously, benefits the gut-brain axis in older rats
Author(s) -
Thomas W. Buford,
Yi Sun,
Lisa M. Roberts,
Anisha Banerjee,
Sujitha Peramsetty,
Anthony Knighton,
Amrisha Verma,
Drake Morgan,
Gonzalo E. Torres,
Qiuhong Li,
Christy S. Carter
Publication year - 2020
Publication title -
geroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.883
H-Index - 63
eISSN - 2509-2715
pISSN - 2509-2723
DOI - 10.1007/s11357-020-00196-y
Subject(s) - probiotic , angiotensin ii , medicine , orally active , pharmacology , endocrinology , oral administration , biology , blood pressure , bacteria , genetics
To (1) investigate the efficacy of multiple doses of an orally delivered probiotic bacteria Lactobacillus paracasei (LP) modified to express angiotensin (1-7) (LP-A) in altering physiologic parameters relevant to the gut-brain axis in older rats and to (2) compare this strategy with subcutaneous delivery of synthetic Ang(1-7) peptide on circulating Ang(1-7) concentrations and these gut-brain axis parameters. Male 24-month-old F344BN rats received oral gavage of LP-A, or subcutaneous injection of Ang(1-7) for 0×, 1×, 3×, or 7×/week over 4 weeks. Circulating RAS analytes, inflammatory cytokines, and tryptophan and its downstream metabolites were measured by ELISA, electrochemiluminescence, and LC-MS respectively. Microbiome taxonomic analysis of fecal samples was performed via 16S-based PCR. Inflammatory and tryptophan-related mRNA expression was measured in colon and pre-frontal cortex. All dosing regimens of LP-A induced beneficial changes in fecal microbiome including overall microbiota community structure and α-diversity, while the 3×/week also significantly increased expression of the anti-inflammatory species Akkermansia muciniphila. The 3×/week also increased serum serotonin and the neuroprotective analyte 2-picolinic acid. In the colon, LP-A increased quinolinate phosphoribosyltransferase expression (1×/week) and increased kynurenine aminotransferase II (1× and 3×/week) mRNA expression. LP-A also significantly reduced neuro-inflammatory gene expression in the pre-frontal cortex (3×/week: COX2, IL-1β, and TNFα; 7×/week: COX2 and IL-1β). Subcutaneous delivery of Ang(1-7) increased circulating Ang(1-7) and reduced angiotensin II, but most gut-brain parameters were unchanged in response. Oral-but not subcutaneous-Ang(1-7) altered physiologic parameters related to gut-brain axis, with the most effects observed in 3×/week oral dosing regimen in older rats.

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