Dietary vitamin A shows promise in Alzheimer's disease intervention, study finds

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A caller study published successful nan diary Frontiers successful Nutrition evaluated nan effects of dietary vitamin A connected nan gut microbiota and intestinal transcriptome.

Alzheimer's illness (AD) is an age-associated neurodegenerative disease. A 2021 study revealed that complete 55 cardinal individuals person dementia globally, pinch low- and middle-income countries accounting for 60% of nan estimate. Given nan aging population, AD prevalence and related economical burdens are expected to increase. Currently, treatments that tin cure AD aliases modify its pathological progression are lacking.

As such, effective guidance and regularisation of associated factors person been paramount. Diet is implicated successful AD prevention and progression, pinch vitamin A arsenic a imaginable prophylactic and therapeutic strategy. Non-genomic actions of vitamin A successful nan encephalon person important roles, and modulating them whitethorn amended encephalon usability and connection therapeutic avenues.

 Nefedova Tanya / ShutterstockStudy: Dietary vitamin A modifies nan gut microbiota and intestinal insubstantial transcriptome, impacting intestinal permeability and nan merchandise of inflammatory factors, thereby influencing Aβ pathology. Image Credit: Nefedova Tanya / Shutterstock

About nan study

In nan coming study, researchers investigated nan effects of dietary vitamin A connected nan intestinal transcriptome, inflammation, gut microbiota, and amyloid-β (Aβ) pathology. Thirty APP/PS1 mice (AD rodent model) were randomly assigned to 3 groups based connected assemblage weight. Mice received a fare pinch deficient (VAD), normal (VAN), aliases enriched (VAS) levels of vitamin A. Body weight and nutrient intake were recorded each week.

Animals were euthanized aft 12 weeks. Sera and fecal samples were collected. Tissues from nan encephalon and nan gut were harvested. Serum levels of intestinal permeability markers, specified arsenic D-lactate and diamine oxidase (DAO), and cytokines, specified arsenic interleukin (IL)-1β, IL-6, and tumor necrosis facet (TNF)-α, were measured utilizing enzyme-linked immunosorbent assay (ELISA). Neurobehavioral functions were assessed successful a six-day Morris h2o maze test.

Accordingly, mice were trained for 4 days, followed by a 60-second hunt for a hidden platform. A discovery trial was performed aft 5 days of training, and nan clip to find nan level was determined. Two tests were administered connected nan concluding day; 1 required locating nan platform's position successful its absence wrong 60 seconds, and successful nan other, nan clip to find nan level was measured.

Further, morphometric and immunohistochemical analyses were performed to measure Aβ deposition successful nan brain. 16S rRNA sequencing was performed to analyse nan gut microbiota. Transcriptomic study of nan intestinal insubstantial was besides performed. Serum vitamin A levels were quantified by liquid chromatography-mass spectrometry.

Findings

There were nary notable changes successful assemblage weight and dietary intake betwixt groups passim nan intervention. However, astatine chopped clip points, nan VAS and VAD groups had little assemblage weight and nutrient intake than nan VAN group. The mean vitamin A levels were 382.61 ng/ml successful nan VAD group, 548.32 ng/ml successful nan VAN group, and 640.85 ng/ml successful nan VAS group. Analysis of variance indicated a important group difference.

The effect of vitamin A connected dietary intake and assemblage weight changes successful APP/PS1 mice. (A) The changes successful assemblage weight of APP/PS1 mice among different groups. (B) The changes successful dietary vitamin A intake among different groups of APP/PS1 mice. *Indicates compared pinch nan VAN group, p < 0.05 indicates statistical significance

The effect of vitamin A connected dietary intake and assemblage weight changes successful APP/PS1 mice. (A) The changes successful assemblage weight of APP/PS1 mice among different groups. (B) The changes successful dietary vitamin A intake among different groups of APP/PS1 mice. *Indicates compared pinch nan VAN group, p < 0.05 indicates statistical significance

Mice successful nan VAN group could straight find nan level and move to its position moreover erstwhile removed. These mice took little clip to find nan level than different groups. Moreover, nan VAS group took little clip than nan VAD group. There were nary important differences successful nan clip spent uncovering nan level betwixt VAS and VAN groups. When nan level was removed, nan VAN group many times crossed nan level area.

Mice successful nan VAD group showed importantly greater Aβ deposition successful nan encephalon than successful different groups. The VAS group besides had higher Aβ deposition than nan VAN group, albeit not statistically significant. The Shannon scale was higher successful nan VAS and VAN groups than successful nan VAD group; however, it was akin betwixt nan VAS and VAN groups. VAN and VAS groups had greater microbial diverseness than nan VAD group.

Overall, 571 genes pinch differential look were identified betwixt nan VAS and VAD groups. Between VAN and VAD groups, 313 differentially expressed genes were identified. Further, location were 243 genes pinch differential look betwixt VAN and VAS groups. DAO and D-lactate levels were importantly elevated successful nan VAD group compared to nan VAS and VAN groups. Mice successful nan VAD group exhibited much important levels of inflammatory cytokines than different groups.

Conclusions

In sum, nan study showed that a 12-week VAD fare reduced serum levels of retinol, impaired cognition, and accrued Aβ pathology successful mice. On nan contrary, a fare enriched pinch vitamin A accrued retinol, reduced Aβ, and preserved cognition. Overall, nan findings item nan value of vitamin A successful AD pathology and behavior.

Journal reference:

  • Wang ZL, Pang SJ, Zhang KW, Li PY, Li PG, nan C. Dietary vitamin A modifies nan gut microbiota and intestinal insubstantial transcriptome, impacting intestinal permeability and nan merchandise of inflammatory factors, thereby influencing Aβ pathology. Front Nutr, 2024, DOI: 10.3389/fnut.2024.1367086, https://www.frontiersin.org/articles/10.3389/fnut.2024.1367086/full