A PRECLINICAL STUDY ON THE MODULATION OF THE MICROBIOTA–GUT–BRAIN AXIS BY A FUNCTIONAL SNACK PROMOTING HEALTHY AGING

Clinical and preclinical studies increasingly report alterations in gut microbial composition and reduced microbial diversity in patients with Alzheimer’s disease (AD), suggesting the gut ecosystem may influence disease onset and progression. Preclinical studies in transgenic AD mouse models indicate that gut dysbiosis could be correlated with impaired intestinal barrier function, local deposition of amyloid-β (Aβ) in the gastrointestinal tract, and regional and systemic inflammatory changes. These alterations have been proposed to accelerate central Aβ accumulation and neuroinflammation through immune and metabolic pathways. Together, these findings support a model in which gut microbiota and mucosal barrier modulation contribute to reinforce the cascade that may promote neuropathology in AD. However, although causal links in humans remain to be fully established. A novel engineered health-promoting cookie formulated with red lentil prebiotics and coated in multi-strain probiotic (SLAB51®)-fortified chocolate was tested in 3xTg-AD mice. At eight weeks of age, mice were divided into experimental groups and subjected to a four-month supplementation protocol. The groups received a functional cookie containing the prebiotic and probiotic formulation, a prebiotic cookie without SLAB51®, a standard recipe cookie, or SLAB51® administered in drinking water. The possible effects on intestinal mucosa morphology, secretion and integrity, neuroplasticity in the enteric and central nervous system, and neuroinflammation were evaluated with biochemical and immunohistochemical approaches. Experimental groups receiving the functional snack exhibited well-preserved intestinal wall architecture and a restoration of epithelial homeostasis. These effects were associated with enhanced mucus layer stability and improved barrier integrity, linked by attenuated pro-inflammatory microenvironment consequent to the decrease in enteric glial cells activation. Furthermore, the intake of this symbiotic formulation preserved cognitive function and was associated with decreased amyloid load, oxidative stress, gliosis, and neuroinflammation in brain areas including the hippocampal region. This symbiotic formulation represents a novel dietary vehicle that may provide a nutritional approach to mitigate AD–related microbiota–gut–brain axis disturbances and promote healthy aging. Funded by Next Generation EU - program “MUR-Fondo Promozione e Sviluppo - D.M. 737/2021, PROTECTIVE, Design and development of probiotic and prebiotic functional cookies to counteract cognitive decline”.