Dysfunction of the Murine Liver with Aging and Its Improvement with the Continuous Consumption of Enterococcus faecalis EC-12.

Chronic inflammation is involved in the development of age-related diseases. Given its persistence, controlling chronic inflammation is essential for preventing age-related diseases. In this study, we investigated the effects of Enterococcus faecalis EC-12 (EC-12), which has immunomodulatory and antioxidant effects, on liver gene expression and aging phenomena in mice. Short-term EC-12 administration stimulated the expression of genes involved in lipid synthesis and metabolism in the liver. Furthermore, long-term EC-12 administration from 10 weeks to 1.5 years of age resulted in significant increases in blood interleukin (IL)-6 and IL-10 concentrations (both p < 0.05) and a significant decrease in the monocyte chemotactic protein-1 concentration (p < 0.05). These results indicated pathologic improvement, such as suppression of fat degeneration in the liver. These results suggest that continuous EC-12 intake from a young age can suppress liver function abnormalities, which is one of the aging phenomena in old age, and contribute to health in old age.

Oral supplementation of a cell preparation of Enterococcus faecalis strain EC-12 stimulates superoxide dismutase production in the livers of healthy and arthritis-induced mice.

Hepatitis, a major human chronic inflammation disease, has been linked to oxidative stress, which can be initiated by radicals produced during the oxidative metabolism. Oxidative damage has been also observed in arthritis-induced mice. Here we evaluated whether supplementation of a cell preparation of Enterococcus faecalis EC-12 could induce superoxide dismutase activity and/or damage in the livers of healthy mice or mice with arthritis. In Experiment 1, both healthy and arthritis-induced mice were orally given a saline solution, or a solution with a low (0.2 mg/mouse/day) or a high (2.0 mg/mouse/day) concentration of E. faecalis EC-12 for 49 consecutive days. Manganese superoxide dismutase activity increased in E. faecalis EC-12-supplemented mice but with no arthritis. In Experiment 2, mice received orally either a saline or an E. faecalis EC-12 suspension (10 mg/kg of body weight/day) for 28 consecutive days. No changes in tissues and levels of function markers and 8-hydroxy-2'-deoxyguanosine were observed in mouse livers, inferring that E. faecalis EC-12 supplementation caused no damage. While mRNA expression of copper/zinc superoxide dismutase remained unaltered, that of manganese superoxide dismutase increased in E. faecalis EC-12 administration mice. In conclusion, at least in healthy mice, E. faecalis EC-12 supplementation stimulated manganese superoxide dismutase activity in liver tissues with no side effects.

Edible bird's nest extract downregulates epidermal apoptosis and helps reduce damage by ultraviolet radiation in skin of hairless mice.

The purpose of the present study was to examine whether daily intake of edible bird's nest extract reduced ultraviolet-induced damage to skin. Twenty-one female HR-1/Hos mice were divided into control (C, n = 7), low-dose (2 mg/kg body weight/day of edible bird's nest extract) (L, n = 7), and high-dose (20 mg/kg body weight/day of edible bird's nest extract) (H, n = 7) groups. With their left back skin covered with aluminum sheet to prevent exposure, mice were radiated with either ultraviolet A (20 J/cm2) or ultraviolet B (40 mJ/cm2) in an alternate manner once daily for 10 weeks. They were gavaged either a solution of saline or edible bird's nest extract every day. The moisture content of the ultraviolet-exposed right back skin was significantly higher in H than in C or L. Histochemical analysis showed that the number of apoptotic epidermal cells on the ultraviolet-exposed skin was significantly lower in L and H than in C. In H, the mRNA expression of superoxide dismutase 2 was significantly higher on ultraviolet-exposed skin than on unexposed skin. Our data suggested that edible bird's nest extract enhanced superoxide dismutase 2 expression and downregulated apoptosis in their epidermis, which likely helped reduce skin damage.

Heat-killed Enterococcus fecalis (EC-12) supplement alters the expression of neurotransmitter receptor genes in the prefrontal cortex and alleviates anxiety-like behavior in mice.

Gut microbiota plays a crucial role in the maintenance of mental health and influences mental disorders such as depression and anxiety. Several studies have reported the beneficial affects of probiotics in mental health. Heat-killed Enterococcus faecalis strain EC-12 (EC-12), a lactic acid bacterium induces activation of the immune system. However, little is known about the effect of EC-12 on mental health. In the present study, the anti-anxiety effect of EC-12 was elucidated in vivo. Male mice fed on diet supplemented with EC-12 showed decreased anxiety-like behavior in open-field and elevated plus-mazetest. In addition, EC-12 supplementation exhibited an anti-depressive trend in mice subjected to forced swim test. The expression of neurotransmitter receptor genes: Adrb3 and Avpr1a were significantly enhanced in EC-12 supplemented mice compared to that of the control mice. In mice, analyses of gut microbiota composition by next generation sequencing revealed significant increase in Butyricicoccus and Enterococcus with EC-12 supplementation. Significant difference was not detected in the expression of neurotransmitter receptor genes in the prefrontal cortex with the administration of sodium butyrate compared to that of the control group. The mechanism associated with EC-12 mediated reduced anxiety-like behavior and altered gene expression in the brain needs to be further elucidated. Taken together, the present study is the first to report the possibility of exploiting the anti-anxiety effect of heat-killed EC-12 as a novel probiotic to promote mental health.

Exploratory investigation of the anti-inflammatory effects of RNase A-treated Enterococcus faecalis strain EC-12.

We previously reported that the major component of Enterococcus faecalis strain EC-12 (EC-12) inducing production of Interleukin (IL)-12 in mouse/human immune cells was its own RNA. This study aimed to investigate if RNase A-treated EC-12 could also produce IL-10 and to evaluate the possible effects of IL-10 produced by RNase A-treated EC-12. Three experiments were conducted: (1) Assessment of the effect of RNase A-treated EC-12 on transcriptome profiles and biological pathways in human peripheral blood mononuclear cells; (2) Determination of cytokine concentration in its culture supernatants; and (3) Supplementation of RNase A-treated EC-12 (RN) to mice with dextran sodium sulfate-induced colitis. Treatment of EC-12 with RNase A inhibited inflammatory response including the potency to induce IL-12 production, while it did not affect IL-10 production (Experiment 1 and 2). Colitis symptoms were milder in RN than in PBS-supplemented controls (Experiment 3). RNase A-treated EC-12 likely became an anti-inflammatory agent primarily inducing IL-10 production.