Normalization of hippocampal retinoic acid level corrects age-related memory deficits in rats

Fabien Dumetz, Corinne Buré, Serge Alfos, Marc Bonneu, Emmanuel Richard, Katia Touyarot, Anaïs Marie, Jean-Marie Schmitter, Clémentine Bosch-Bouju, Véronique Pallet
Neurobiology of Aging. 2019-09-01; :
DOI: 10.1016/j.neurobiolaging.2019.09.016

Dietary micronutrients constitute a major environmental factor influencing aging processes. Vitamin A (vit. A) is the precursor of retinoic acid, a bioactive molecule that controls the expression of several genes involved in brain function. Evidence suggest a reduction of vit. A bioavailability with aging, but its impact on neuronal network is poorly understood. We investigated the mechanisms linking memory impairments with specific alterations of retinoic acid metabolism in the hippocampus. We compared young (10 weeks) and aged (16 months) rats, supplemented or not with dietary vitamin A (20 IU retinol/g) for 4 weeks. Our study reveals that aging induced dysregulation of gene expression involved in vit. A and retinoic acid metabolism in the liver. Furthermore, vit. A supplementation restored the integrity of the hippocampal neuronal morphology altered by aging. Importantly, we found a high correlation between hippocampal levels of retinoic acid and memory performance. The present work establishes the link between collapse of retinoid metabolism and age-related cognitive decline, highlighting the role of vit. A in maintaining memory through aging.

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