Supplementation with Lactobacillus plantarum WCFS1 Prevents Decline of Mucus Barrier in Colon of Accelerated Aging Ercc1−/Δ7 Mice

Abstract

Although it is clear that probiotics improve intestinal barrier function, little is known about the effects of probiotics on the aging intestine. We investigated effects of 10-week bacterial supplementation of <i>Lactobacillus plantarum</i> WCFS1, <i>Lactobacillus casei</i> BL23, or <i>Bifidobacterium breve</i> DSM20213 on gut barrier and immunity in 16-week-old accelerated aging <i>Ercc1^-/Δ7</i> mice, which have a median lifespan of ~20 weeks, and their wild-type littermates. The colonic barrier in <i>Ercc1^-/Δ7</i> mice was characterized by a thin (< 10 μm) mucus layer. <i>L. plantarum</i> prevented this decline in mucus integrity in <i>Ercc1^-/Δ7</i> mice, whereas <i>B. breve</i> exacerbated it. Bacterial supplementations affected the expression of immune-related genes, including Toll-like receptor 4. Regulatory T cell frequencies were increased in the mesenteric lymph nodes of <i>L. plantarum</i>- and <i>L. casei</i>-treated <i>Ercc1^-/Δ7</i> mice. <i>L. plantarum</i>- and <i>L. casei</i>-treated <i>Ercc1^-/Δ7</i> mice showed increased specific antibody production in a T cell-dependent immune response <i>in vivo</i>. By contrast, the effects of bacterial supplementation on wild-type control mice were negligible. Thus, supplementation with <i>L. plantarum</i> - but not with <i>L. casei</i> and <i>B. breve -</i> prevented the decline in the mucus barrier in <i>Ercc1^-/Δ7</i> mice. Our data indicate that age is an important factor influencing beneficial or detrimental effects of candidate probiotics. These findings also highlight the need for caution in translating beneficial effects of probiotics observed in young animals or humans to the elderly.