Probiotic Modulation in Aging: Strain-Specific Geroprotective Effects in <i>Caenorhabditis elegans</i>.

Elderly individuals are more vulnerable to disease due to their increased frailty. Emerging evidence highlights the potential of probiotics as geroprotective agents by maintaining gut health and modulating key physiological processes involved in aging, such as inflammation, cognitive functions, and metabolism. Here, we investigated the geroprotective potential of four probiotic strains (<i>Lacticaseibacillus paracasei</i> LPC1114, <i>Limosilactobacillus reuteri</i> PBS072, <i>Bifidobacterium breve</i> BB077, and <i>Bifidobacterium animalis</i> subsp. <i>lactis</i> BL050) using <i>Caenorhabditis elegans</i> as an aging model. Mid-life healthspan(definition) parameters were assessed, including lifespan, motility, ROS levels, lipofuscin accumulation, and cognitive capabilities. The probiotics exhibited strain-specific effects. <i>L. reuteri</i> PBS072 and <i>B. lactis</i> BL050 significantly increased locomotion by 20% and decreased ROS levels by 70% and 30% respectively, suggesting enhanced oxidative stress response and neuromuscular maintenance. <i>B. breve</i> BB077, <i>L. paracasei</i> LPC1114, and <i>L. reuteri</i> PBS072 enhanced associative learning performance, whereas <i>B. lactis</i> BL050 improved chemotactic response. Notably, only <i>L. paracasei</i> LPC1114 and <i>L. reuteri</i> PBS072 extended the maximum lifespan by 4 and 5 days, respectively, an effect mediated by the longevity-related genes <i>skn1</i>, <i>sir2.1</i>, and <i>daf16</i>. Our findings highlight the multifaceted, strain-specific geroprotective properties of probiotics and support their potential as microbiome-based interventions to promote healthy aging.