Lactobacillus Rhamnosus HN001 Research Articles

Immune enhancement conferred by oral delivery of Lactobacillus rhamnosus HN001 in different milk-based substrates.

The probiotic Lactobacillus rhamnosus HN001 is known to enhance immunity in animal models, following oral delivery. In this study, we investigated the immunoenhancing effects of HN001 delivered to mice in different milk-based substrates, including: whole (full-fat) milk supplemented with HN001; fermented milk supplemented with HN001; or whole milk which had been part-fermented by HN001. Direct oral feeding of mice with HN001 in whole milk was shown to enhance the phagocytic activity of blood and peritoneal cells. Similar effects on phagocytosis were observed when UN001 was offered to mice in the form of a milk- or fermented milk-based diet. The degree of immune enhancement conferred by HN001 was similar whether the probiotic was used as an additive or as a fermentative agent. These studies confirm that Lb. rhamnosus HN001, derived originally from dairy food, enhances immune function following oral delivery in different milk bases.

Systemic Immunity-Enhancing Effects in Healthy Subjects Following Dietary Consumption of the Lactic Acid Bacterium Lactobacillus rhamnosus HN001

Objective: To determine the effects of the probiotic lactic acid bacterium, Lactobacillus rhamnosus HN001, on natural cellular immunity when delivered orally in normal low-fat milk (LFM) or lactose-hydrolyzed low-fat milk (LFM-LH).Design: A three stage, pre-post intervention trial, spanning nine weeks.Setting: Taipei Medical College Hospital, Taipei, Taiwan.Subjects: Fifty-two healthy middle-aged and elderly volunteers (17 males, 35 females; median age 63.5, range 44–80).Interventions: Stage 1 (run-in diet): 25g/200 mL reconstituted LFM powder, twice daily for 3 weeks. Stage 2 (probiotic intervention): LFM or LFM-LH, supplemented with 109 CFUs/g L. rhamnosus HN001 in each case, for 3 weeks. Stage 3 (wash-out): LFM for 3 weeks.Measures of Outcome: In vitro phagocytic capacity of peripheral blood polymorphonuclear (PMN) leukocytes; in vitro tumoricidal activity of natural killer (NK) leukocytes.Results: Immunological responses were unaffected by the run-in diet of LFM alone. In contrast, the relative proportion of PMN cells showing phagocytic activity increased by 19% and 15%, respectively, following consumption of HN001 in either LFM or LFM-LH; the relative level of NK cell tumor killing activity increased by 71% and 147%. In most cases these levels declined following cessation, but remained above baseline.Conclusions: Dietary consumption of L. rhamnosus HN001, in a base of low-fat milk or lactose-hydrolyzed low-fat milk, appears to enhance systemic cellular immune responses and may be useful as a dietary supplement to boost natural immunity.

Potential probiotic lactic acid bacteria Lactobacillus rhamnosus (HN001), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019) do not degrade gastric mucin in vitro

The mucus layer (mucin) coating the surface of the gastrointestinal tract (GIT) plays an important role in the mucosal barrier system. Any damage or disturbance of this mucin layer will compromise the host’s mucosal defence function. In the present study, the ability of three potential probiotic lactic acid bacteria (LAB) strains ( Lactobacillus rhamnosus HN001, Lactobacillus acidophilus HN017, Bifidobacterium lactis HN019) to degrade mucin in vitro was evaluated, in order to assess their potential pathogenicity and local toxicity. The LAB strains were incubated in medium containing hog gastric mucin (HGM, 0.3%) at 37°C for 48 h, following which any decrease in carbohydrate and protein concentration in the ethanol-precipitated portion of the culture medium was determined, using phenol–sulphuric acid and bicinchonic acid (BCA) protein assays, respectively. The change in molecular weight of mucin glycoproteins, following incubation with the test strains, was monitored by SDS–polyacrylamide gel electrophoresis (SDS–PAGE). In order to expose any ability of the test strains to degrade mucin visually and more directly, the test strains were also cultured on agarose containing 0.3% HGM and incubated anaerobically for 72 h at 37°C. No significant change in the carbohydrate or protein concentration in mucin substrates was found following incubation with the test strains. No mucin fragments were derived from the mucin suspension incubated with test strains, and no mucinolysis zone was identified on agarose. These results demonstrate that the potential probiotic LAB strains tested here were unable to degrade gastrointestinal mucin in vitro, which suggests that these novel probiotic candidates are likely to be non-invasive and non-toxic at the mucosal interface.

Probiotic supplementation to enhance natural immunity in the elderly: effects of a newly characterized immunostimulatory strain Lactobacillus rhamnosus HN001 (DR20™) on leucocyte phagocytosis

Consumption of some species and strains of lactic acid bacteria (LAB) has been shown to enhance immunity in humans. In this study, the effect of dietary supplementation with Lactobacillus rhamnosus HN001 (DR20™), a newly characterized LAB strain, on immune cell function in healthy elderly subjects was investigated. The study comprised three stages, each lasting 3 weeks. In stages 1 (run-in) and 3 (washout), subjects ( n = 13) received low fat milk (LFM, 200 mL twice daily) as a base diet. In Stage 2 (supplement intervention), subjects received LFM supplemented with L. rhamnosus HN001 (1.25 × 10 8 CFU/mL). Assessment of immune function was made at the beginning, and the end of each stage. Consumption of milk supplemented with L. rhamnosus HN001 for three weeks resulted in a significant increase in the phagocytic activity of peripheral blood polymorphonuclear cells and monocytes. These responses returned to baseline following 3 weeks washout with un-supplemented milk. This suggests that L. rhamnosus HN001 is able to enhance aspects of natural immunity in humans, and could be used as a dietary adjunct for optimizing immune responsiveness in the elderly.

Safety assessment of potential probiotic lactic acid bacterial strains Lactobacillus rhamnosus HN001, Lb. acidophilus HN017, and Bifidobacterium lactis HN019 in BALB/c mice

The general safety of immune-enhancing lactic acid bacteria (LAB) strains Lactobacillus rhamnosus HN001 (DR20™), Lb. acidophilus HN017, and Bifidobacterium lactis HN019 (DR10™) was investigated in a feeding trial. Groups of BALB/c mice were orally administered test LAB strains or the commercial reference strain Lb. acidophilus LA-1 at 2.5×10 9, 5×10 10 or 2.5×10 12 colony forming units (CFU)/kg body weight/day for 4 weeks. Throughout this time, their feed intake, water intake, and live body weight were monitored. At the end of the 4 week observation period, samples of blood, liver, spleen, kidney, mesenteric lymph nodes, and gut tissues (ileum, caecum, and colon) were collected to determine: haematological parameters (red blood cell and platelet counts, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration); differential leukocyte counts; blood biochemistry (plasma total protein, albumin, cholesterol, and glucose); mucosal histology (epithelial cell height, mucosal thickness, and villus height); and bacterial translocation to extra-gut tissues (blood, liver, spleen, kidney and mesenteric lymph nodes). DNA finger printing techniques were used to identify any viable bacterial strains recovered from these tissues. The results demonstrated that 4 weeks consumption of these LAB strains had no adverse effects on animals’ general health status, haematology, blood biochemistry, gut mucosal histology parameters, or the incidence of bacterial translocation. A few viable LAB cells were recovered from the tissues of animals in both control and test groups, but DNA fingerprinting did not identify any of these as the inoculated strains. The results obtained in this study suggest that the potentially probiotic LAB strains HN001, HN017, and HN019 are non-toxic for mice and are therefore likely to be safe for human use.

Acute oral toxicity and bacterial translocation studies on potentially probiotic strains of lactic acid bacteria

Three potentially probiotic lactic acid bacteria (LAB) strains, Lactobacillus rhamnosus HN001 (DR20 TM), Lb. acidophilus HN017 and Bifidobacterium lactis HN019 (DR10 ™), have recently been identified and characterized. The present study was designed to evaluate the acute oral toxicity of these strains to mice, and also to investigate bacterial translocation and gut mucosal pathology in BALB/c mice fed HN019, HN001 or HN017 for 8 consecutive days at a high dose of 10 11cfu/mouse/day. Results showed that these probiotic strains had no adverse effect on general health status, feed intake, body weight gain and intestinal mucosal morphology (villus height, crypt depth, epithelial cell height and mucosal thickness). No viable bacteria were recovered from blood and tissue samples (mesenteric lymph nodes, liver and spleen) of mice, and no treatment-associated illness or death was observed. According to these results, the oral LD 50 of HN019, HN001 and HN017 is more than 50 g/kg/day for mice, and their acceptable daily intake (ADI) value is 35 g dry bacteria per day for a 70-kg person. This suggests that the probiotic strains HN019, HN001 and HN017 are non-pathogenic and likely to be safe for human consumption.

Probiotic lactic acid bacteria (Lactobacillus acidophilus HN017, Lactobacillus rhamnosus HN001 and Bifidobacterium lactis HN019) have no adverse effects on the health of mice

Abstract The safety of the probiotic lactic acid bacteria Lactobacillus acidophilus (HN017), Lactobacillus rhamnosus (HN001, DR20 ™ ), and Bifidobacterium lactis (HN019, DR10 ™ ), was studied in BALB/c mice fed with different doses (5×10 7 , 10 9 or 5×10 10 cfu/mouse/day) of the bacteria for 7 days. No abnormal clinical signs were observed in any of the groups during the period of the experiment. There were no significant differences in feed intake, water intake, or liveweight gain among mice fed the different probiotics, in comparison to a control group which was not fed with LAB. No bacteria were detected in the spleen of any animals. Although one mouse from each of the groups fed with Lb. rhamnosus HN001 or B. lactis HN019 had lactic acid bacteria detected in their kidney, DNA finger-printing analysis showed that the isolates were different from the test probiotic strains. Histological and haematological parameters also indicated that the lactic acid bacterial strains did not adversely affect the health of the mice.