HK L-137 Research Articles

Beneficial effect of heat-killed Lactiplantibacillus plantarum L-137 on intestinal barrier function of rat small intestinal epithelial cells

Heat-killed Lactiplantibacillus plantarum L-137 (HK L-137) has been suggested to enhance the intestinal barrier in obese mice, leading to improvement of metabolic abnormalities and adipose tissue inflammation, and in healthy humans with overweight, leading to improvement of systemic inflammation. However, its detailed mechanism of action has not been clarified. Therefore, this study investigated the effects of HK L-137 on the permeability of rat small intestinal epithelial IEC-6 cells, tight junction-related gene and protein expression and localization, and intracellular signaling pathways involved in barrier function. Treatment of IEC-6 cells with HK L-137 for 26 h significantly reduced the permeability to fluorescein isothiocyanate-dextran (FD-4). HK L-137 also increased gene and protein expression of zonula occludens-1 (ZO-1), an important tight junction protein, without affecting the localization. Furthermore, inhibition of the extracellular signal-regulated kinase (ERK)1/2 pathway in IEC-6 cells canceled the HK L-137-related reduction in permeability to FD-4. Phosphorylation of ERK in IEC-6 cells was induced 15 min after the addition of HK L-137. These results suggest that HK L-137 reduces intestinal permeability partly through activating the ERK pathway and increasing expression of the ZO-1 gene and protein. Enhancement of intestinal barrier function with HK L-137 might be effective in preventing and treating leaky gut, for which no specific therapeutic tool has been established.

Evaluation of the in vivo and in vitro interleukin-12 p40 and p35 subunit response in yellowtail (Seriola quinqueradiata) to heat-killed Lactobacillus plantarum strain L-137 (HK L-137) supplementation, and immersion challenge with Lactococcus garvieae

Dietary supplementation of immunostimulants might be effective to reduce the economic losses due to infectious diseases and the use of antibiotics in aquaculture. To investigate the immune response of interleukin-12 (IL-12) in yellowtail Seriola quinqueradiata to heat-killed Lactobacillus plantarum strain L-137 (HK L-137), we performed a leukocyte culture, feeding trial with diets containing L-137 and an immersion challenge with Lactococcus garvieae. IL-12 (IL-12p70) is a heterodimeric cytokine composed of IL-12p35 and IL-12p40 subunits. In the yellowtail-leukocyte culture, HK L-137 treatment stimulated the mRNA expression of one IL12p35 subunit (p35a) and all IL12p40 subunits (p40a, p40b, and p40c) in a dose-dependent manner. Furthermore, mRNA expression of type-I helper (Th-1) cytokine (tumor necrosis factor α, TNF-α, and interferon γ, IFN-γ) was also stimulated by HK L-137. After 6 weeks of feeding yellowtails with diets containing 0, 20, and 100 ppm of HK L-137, the mRNA expression of p35a and p40b in the spleen leukocytes increased with the dietary concentration of HK L-137, and that of p40b, p40c, and ifng in the head kidney leukocytes were the highest in the 20 ppm HK L-137 group. Survival rates in the 20 ppm HK L-137 group after immersion challenge with L. garvieae were significantly higher than the control (0 ppm of HK L-137). The 100 ppm HK L-137 group did not significantly suppress mortality. HK L-137 showed immunostimulant activity by increasing the expression of il-12, tnfa, and ifng mRNA in both in vitro and in vivo tests in yellowtail. Our results suggest that dietary supplementation with 20 ppm HK L-137 is the most efficient dose for improving immunity in yellowtail. Furthermore, a high dose of HK L-137 and/or long-term feeding of a diet containing HK L-137 might suppress the immune response, which probably decreases the survival rate of fish. To maintain a high immune response in yellowtail, the optimal dietary concentration of HK L-137 and/or feeding regime should be investigated further.

From a cell model to a fish trial: Immunomodulatory effects of heat-killed Lactiplantibacillus plantarum as a functional ingredient in aquafeeds for salmonids.

Paraprobiotics (dead/inactivated probiotics) are promising candidates in functional feeds to promote growth performance, modulate intestinal microbiota and enhance immune response of fish. During industrial production, fish are exposed to several stressful conditions such as handling, sub-optimal nutrition and diseases that can lead to reduced growth, increased mortalities and large economical losses. Such problems can be mitigated by use of functional feeds, leading to more-sustainable aquaculture and improved animal welfare. Lactiplantibacillus plantarum strain L-137 is a common bacterium found in fermented Southeast Asian dish made from fish and rice. The benefits of its heat-killed form (HK L-137) related to growth performance and immunomodulation have been studied in farmed fish such as Nile Tilapia (Oreochromis niloticus), striped catfish (Pangasianodon hypophthalmus) and bighead catfish (Clarias macrocephalus). To study if such benefits can also be observed in salmonids, we worked both at in vitro level using an intestinal epithelium cell line from rainbow trout (Oncorhynchus mykiss; RTgutGC) stimulated with HK L-137 (Feed LP20™) and at in vivo level with pre-smolt Atlantic salmon (Salmo salar) fed HK L-137 at different inclusion levels (20, 100 and 500 mg of Feed LP20™ kg-1 feed). In RTgutGC, the results showed that the barrier function of the cell monolayer was strengthened along with an increased production of IL-1β and a decreased production of Anxa1, indicating a modulation of the immune response. Interestingly, a similar trend was detected at the in vivo level in distal intestine from fish fed the highest inclusion level of HK L-137. Here, a lower production of Anxa1 was also detected (after a 61-day feeding period) in addition to an increase of total plasma IgM in the same group. Furthermore, the RNA-seq analysis showed that HK L-137 was able to modulate the gene expression of pathways related to molecular function, biological process and cellular component in distal intestine, without compromising fish performance and gut microbiota. Taken together, our study has shown that HK L-137 can modulate physiological response of Atlantic salmon, making fish more robust against stressful conditions during production.

Effects of Heat-Killed Lactobacillus plantarum L-137 Supplementation on Growth Performance, Blood Profiles, Intestinal Morphology, and Immune Gene Expression in Pigs.

In the present study, the effects of dietary heat-killed Lactobacillus plantarum L-137 (HK L-137) on the productive performance, intestinal morphology, and cytokine gene expression of suckling-to-fattening pigs were investigated. A total of 100 suckling pigs [(Large White × Landrace) × Duroc; 4.5 ± 0.54 kg initial body weight (BW)] were used and assigned to each of the four dietary treatments as follows: (1) a control diet with antibiotics as a growth promoter (AGP) from the suckling phase to the grower phase and no supplement in the finisher phases; (2) a control diet without antibiotics as a growth promoter (NAGP); (3) a control diet with HK L-137 at 20 mg/kg from the suckling phase to the starter phase and no supplement from the grower phase to the finisher phases (HKL1); and (4) a control diet with HK L-137 at 20 mg/kg from the suckling phase to the weaner phase, at 4 mg/kg from the starter phase to the finisher 1 phase, and no supplement in the finisher 2 phase (HKL2). During the weaner-starter period, the pigs fed on the AGP and HKL2 diets showed significantly higher weight gain and average daily gain (ADG) than those in the NAGP group (p < 0.05). The pigs in the AGP, HKL1, and HKL2 groups showed greater ADG than those in the NAGP groups (p < 0.05) throughout the grower-finisher period. The suckling pigs in the HKL1 and HKL2 groups showed a higher platelet count (484,500 and 575,750) than in the others (p < 0.05); however, there were no significant differences in the other hematological parameters among the treatment groups. The relative mRNA expression level of IFN- ß of the suckling and starter pigs were significantly higher in the HKL1 and HKL2 groups than in the others (p < 0.05), while the IFN-γ showed the highest level in the HKL2 suckling pigs (p < 0.05). These results demonstrate that a HK L-137 supplementation could stimulate the immune response in suckling and starter pigs and promote the growth performance in finishing pigs.

Beneficial Effect of Heat-Killed Lactiplantibacillus plantarum L-137 on Skin Functions in Healthy Participants: A Randomized, Placebo-Controlled, Double-Blind Study.

To determine whether consuming heat-killed Lactiplantibacillus plantarum L-137 (HK L-137) influences skin functions, we performed a randomized, placebo-controlled, double-blind study in healthy participants who were conscious of dry skin. A total of 80 healthy participants (20 men, 60 women; mean age, 47.3 years) were assigned to receive a tablet containing HK L-137 or a placebo tablet daily for 12 weeks. Every 4 weeks, the skin water content and transepidermal water loss (TEWL) were measured at the forearm and face, and participants completed two skin-related questionnaires, the Dermatology Life Quality Index and a self-evaluation. The HK L-137 group tended to show greater increases from baseline of water content at the forearm and larger decreases of TEWL at the face. The total scores of both questionnaires improved significantly more in the HK L-137 group. Water content and TEWL improved significantly in participants in the HK L-137 group who were above the median age of study participants or had relatively dry skin. These findings suggest that daily HK L-137 intake can improve dry skin, thereby contributing to skin satisfaction.

Effects of dietary supplementation of heat-killed Lactobacillus plantarum L-137 on growth performance and immune response of bighead catfish (Clarias macrocephalus)

The aim of this study was to determine the effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on the growth performances and immune response of juvenile bighead catfish (Clarias macrocephalus). The experiment was conducted with four iso-nitrogenous (44.8 % crude protein) and iso-caloric (20.17 KJ g−1) diets supplemented with different levels (0, 10, 20, and 50 mg kg−1) of HK L-137. The bighead catfish (n = 1800, average body weight: 9.69 ± 0.24 g) were randomly introduced to 200-L composite tanks (filled with 150 L of fresh water) and stocked at 150 fish tank−1 in triplicates per dietary treatment for 60 days. The results showed that the diets supplemented with 10, 20, and 50 mg kg−1 of HK L-137 significantly increased the growth, protein efficiency ratio, feed conversion ratio, survival rate, and lysozyme activity compared to the control. Furthermore, the diets supplemented with 20 and 50 mg kg−1 or 10 and 20 mg kg−1 of HK L-137 significantly enhanced the total white blood cell count or apparent digestibility coefficient of the fish, respectively. The fish fed the HK L-137 diets (at 10, 20, and 50 mg kg−1) revealed lower cumulative mortality than the control after challenge with Aeromonas hydrophila. Our results suggested that dietary supplementation of 10 mg kg−1 HK L-137 is the most efficient in improving the performance and immunity of bighead catfish; however, this should be confirmed in further study under full-scale commercial trials.

Safety and efficacy of using heat-killed Lactobacillus plantarum L-137: High-dose and long-term use effects on immune-related safety and intestinal bacterial flora

Heat-killed Lactobacillus plantarum L-137 (HK L-137) promotes immune function in animals. In healthy people, T-cell proliferation was shown to be enhanced by taking 10 mg HK L-137 daily for 12 weeks. However, the safety and efficacy of higher doses or longer treatments have not yet been investigated in humans. To investigate the high-dose and long-term use effects of HK L-137 on immune-related safety and on host intestinal bacterial flora, 15 healthy volunteers took a daily HK L-137 (50 mg) preparation for 4 weeks. An additional 29 participants who regularly visited a clinic for health care took HK L-137 (10 mg) daily for 12 months. Measures for anthropometrics, hematology, biochemistry, and urinalysis were taken at scheduled timepoints for all participants. Stool and blood samples were also collected and evaluated for microbes and short-chain fatty acids (SCFA); isolated T-cells were assessed for levels of proliferation induced by phytohemagglutinin in the long-term study. Adverse events or shifts in clinical measures from normal ranges due to the dietary intervention were not observed in the high-dose or long-term studies. Long-term intake also did not result in immune exhaustion due to any chronic immunostimulation; ex vivo T-cell proliferation was significantly greater at 12 months than at baseline (p < 0.01). In addition, the Firmicutes/Bacteroidetes ratio in stool samples was significantly lower at 12 months than at baseline (p < 0.05) due to the long-term intake of the HK L-137. Lastly, fecal SCFA concentrations were significantly greater (p < 0.05) at 6 months than at baseline. From these data, it can be concluded that the efficacy of HK L-137 is maintained with no overt adverse effects as a result of high-dose and/or long-term consumption.

Heat-killed Lactobacillus plantarum L-137 attenuates obesity and associated metabolic abnormalities in C57BL/6 J mice on a high-fat diet.

Heat-killed Lactobacillus plantarum L-137 (HK L-137) has anti-allergic, antitumor, and antiviral effects in mice, as well as an anti-inflammatory effect in rats with metabolic syndrome through regulation of immunity. To evaluate the influence of HK L-137 on chronic inflammation in mice with diet-induced obesity, C57BL/6 J mice were fed a normal diet (16% of energy as fat) or a high-fat diet (62% of energy as fat) with or without 0.002% HK L-137 for 4 to 20 weeks. It was found that HK L-137 supplementation alleviated weight gain and elevation of plasma glucose, cholesterol, alanine aminotransferase, and aspartate transaminase levels in mice with diet-induced obesity. Expression of several inflammation-related genes, including F4/80, CD11c, and IL-1β, in the epididymal adipose tissue of these mice was significantly downregulated by HK L-137. In addition, plasma levels of lipopolysaccharide-binding protein, a marker of endotoxemia, tended to be decreased by administration of HK L-137. These findings suggest that HK L-137 supplementation ameliorates obesity-induced metabolic abnormalities and adipose tissue inflammation, possibly through improvement of intestinal permeability.

Effects of heat killed Lactobacillus plantarum (HK L-137) supplemental diets on growth, survival and health of juvenile striped catfish, Pangasianodon hypophthalmus

The present study was conducted to determine the effects of dietary heat killed Lactobacillus plantarum (HK L-137) on growth, survival, and immune response of juvenile striped catfish (Pangasianodon hypophthalmus).

Daily intake of heat-killed Lactobacillus plantarum L-137 improves inflammation and lipid metabolism in overweight healthy adults: a randomized-controlled trial

PurposeThe effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on inflammation and lipid metabolism were investigated in overweight volunteers.MethodsOne hundred healthy subjects with a body mass index from 23.0 to 29.9 (51 men and 49 women; mean age: 41.4 years) were enrolled in this randomized, double-blind, placebo-controlled, parallel group study. Subjects were randomly assigned to daily administration of a tablet containing HK L-137 (10 mg) or a placebo tablet for 12 weeks. Blood samples were collected every 4 weeks to measure biomarkers of lipid metabolism and inflammatory mediators.ResultsThe percent change of concanavalin A-induced proliferation of peripheral blood mononuclear cells was significantly larger in the HK L-137 group than in the control group, similar to previous studies. The decreases of aspartate aminotransferase and alanine aminotransferase over time were significantly larger in the HK L-137 group than in the control group, as were the decreases of total cholesterol, low-density lipoprotein cholesterol, and the leukocyte count at one time point. These effects of HK L-137 were stronger in the subjects with higher C-reactive protein levels.ConclusionsThese findings suggest that daily intake of HK L-137 can improve inflammation and lipid metabolism in subjects at risk of inflammation.

The effects of heat-killed Lactobacillus plantarum L-137 supplementation on growth performance, intestinal morphology, and immune-related gene expression in broiler chickens

The present study was conducted to investigate the effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) supplementation on the growth performance, intestinal morphology, and immune-related gene expression in broiler chickens. A total of 600 5-day-old male Ross 308 broilers were randomly separated in a completely randomized design with to 2 dietary treatments, each with 6 replicates of 50 birds. The basal diets were formulated and prepared using HK L-137 at a level of 0 or 10 mg/kg. Chickens were fed basal diets with or without HK L-137 from 5 to 42 days of age. In addition to performance parameters, 5 birds with a live weight close to the group average were selected from each group and euthanized to collect their spleens for gene expression analysis (at 5, 10, 22, and 42 days old) as well as the whole small intestine for morphological analysis (at 22 and 42 days old). Thirty chickens with uniform weight from each group were slaughtered at the last trial day to measure carcass characteristics. Results showed that HK L-137 supplementation from the 5th to the 22nd day could enhance the body weight (BW), and average daily gain (ADG) in broilers (P < 0.05), and showed a lower value (P < 0.05) of average daily feed intake (ADFI). HK L-137 fed birds showed a significant improvement (P < 0.05) in BW, weight gain, and feed conversion ratio (FCR) at 42 days old, but there were no significant differences on feed intake, survival rate, carcass characteristic, and visceral organs. The intestinal morphometric examination of the broilers at 22 days-old showed that villus height (VH), villus area (VA), and the ratio of VH and crypt depth (CD; VH/CD ratio) trended to be higher in the HK L-137 group. The duodenal VH and jejunal VH/CD ratio significantly increased (P < 0.05) in birds fed HK L-137. This might indicate that the birds fed dietary HK L-137 might have increased growth rate due to the increased VH and VH/CD ratio, resulting in raising the absorptive surface area for available nutrients. However, chickens at 42 days old presented that the intestinal VH, VA, CD, and VH/CD ratio did not differ between dietary groups (P > 0.05). The gene expression levels of IL-12β, IFN-β, and IFN-γ in HK L-137 group were significantly higher than those of the control (P < 0.05, P < 0.01, P < 0.05, respectively) at 22 days of age. These results suggest that HK L-137 has some properties to stimulate the growth performance and immune response in young broiler chickens, and thus that it may be a potential alternative replacement for antibiotic growth promoters (AGPs) in the broiler chicken industry.

Lactobacillus plantarum L-137 upregulates hyaluronic acid production in epidermal cells and fibroblasts in mice.

Heat-killed Lactobacillus plantarum L-137 (HK L-137), an immunobiotic lactic acid bacterium, has been reported to enhance IFN-γ production through induction of IL-12. In this study, we investigated the effects of HK L-137 on skin moisturizing and production of hyaluronic acid (HA), an extracellular matrix associated with the retention of skin moisture. Oral administration of HK L-137 suppressed the loss of water content in the stratum corneum in hairless mice. Treatment of primary epidermal cells with HK L-137 increased HA production. Supernatant from immune cells stimulated by HK L-137, which contained proinflammatory cytokines such as IL-12, TNF-α, and IFN-γ, upregulated HA production and hyaluronan synthase 2 (HAS2) messenger RNA expression by BALB/3T3 fibroblasts via activation of transcription factor nuclear factor κB (NFκB). Although treatment of the supernatant with anti-TNF-α antibody (Ab) alone did not inhibit the HA production, combination of anti-TNF-α Ab with anti-IFN-γ Ab significantly inhibited the HA production. Thus, HK L-137-induced IFN-γ plays a critical role in upregulated HA production in collaboration with TNF-α. HK L-137 may be useful for improvement of skin functions such as moisture retention by inducing HA production.

Synergetic Effects of Lactobacillus plantarum and β-Glucan on Digestive Enzyme Activity, Intestinal Morphology, Growth, Fatty Acid, and Glucose-Related Gene Expression of Genetically Improved Farmed Tilapia

The current study was conducted to evaluate the synergetic effects of heat-killed Lactobacillus plantarum (HK L-137) and β-glucan (BG) on digestive enzyme activity and intestinal morphology of genetically improved farmed tilapia (GIFT) with focus on insulin-like growth factor I (IGF-I), fatty acid synthase (FAS), and glucose-6-phosphate dehydrogenase (G6PD). For 12weeks, fish fed the control, or three diets incorporated with 100 HK L-137, 100 BG, or 50 HK L-137 + 50 BGmg/kg (HK L-137, BG, and HK L-137/BG diets). After final sampling, fish fed HK L-137 or HK L-137/BG diets exhibited significantly (P < 0.05) increased final body weight and weight gain while the specific growth rate and feed efficiency ratio enhanced only in HK L-137/BG group. Mucosal and villi lengths and muscle thickness significantly (P < 0.05) increased by HK L-137 or/and BG for the middle intestine. Lipase and protease improved significantly (P <0.05) in fish fed both HK L-137 and BG when compared to the control group. Interestingly, qRT-PCR revealed a significant (P < 0.05) upregulation in the IGF-1 gene expression in fish fed HK L-137 or/and BG additives compared to the control. Muscle and liver G6PD gene expression were upregulated significantly (P <0.05) in fish fed HK L-137/BG diet as compared to the control group. In addition, feeding HK L-137 or both additives effectively elevated the hematocrit, hemoglobin, and WBCs and decreased triglyceride and glucose levels. Accordingly, the use of both HK L-137 and BG is an efficient scheme to reach economically feasible and sustainable tilapia production.

Modulation of digestive enzyme activity, blood health, oxidative responses and growth-related gene expression in GIFT by heat-killed Lactobacillus plantarum (L-137)

The current study was performed to investigate the effects of dietary heat-killed Lactobacillus plantarum (HK L-137) on growth, digestive enzyme activity, intestinal morphology and oxidative status in genetically improved farmed tilapia (GIFT). For 12 weeks, fish were fed a control diet (HKL0) or a diet supplemented with HK L-137 at a concentration of 50 (HKL50), 100 (HKL100) or 1000 (HKL1000) mg kg−1 feed. At the final sampling, the HKL100 group had significantly (P < 0.05) increased performance parameters (FBW, WG, SGR and FER) compared to the control group, while the HKL50 and HKL1000 groups showed weaker improvements. Mucosal thickness and villus length were significantly (P < 0.05) increased in the HKL50 and HKL100 groups in the anterior, middle and posterior intestine, but muscle thickness was significantly (P < 0.05) improved only in the anterior and middle intestine. Amylase, lipase and protease activity was significantly (P < 0.05) increased in fish fed 50 or 100 mg HK L-137 per kg diet compared to control fish. Significant modulation of blood haematocrit, haemoglobin levels, and RBC and WBC counts (P < 0.05) occurred in fish fed HK L-137, while total cholesterol and GPT were decreased by HK L-137. Furthermore, antioxidative enzyme (SOD and CAT) activity were significantly (P < 0.05) higher in the HKL100 group than in the control group, while MDA levels were lower. Furthermore, fish fed HK L-137 showed enhanced total serum protein and IgM levels. Interestingly, qRT-PCR revealed significant (P < 0.05) upregulation of the growth-related gene IGF-I and the glucose regulation gene G6PD but downregulation of the fatty acid synthase (FAS) gene in all HKL groups compared to the control group. Thus, we conclude that the use of HK L-137 is an efficient strategy to achieve economically feasible and sustainable tilapia production.

Evaluation of dietary Heat-killed Lactobacillus plantarum strain L-137 supplementation on growth performance, immunity and stress resistance of Nile tilapia (Oreochromis niloticus)

Four feeding trials were carried out to investigate the effect of immunobiotic (Heat-killed Lactobacillus plantarum strain L-137-HK L-137) supplement in diets on growth, immune responses and stress resistance of Nile tilapia (Oreochromis niloticus). For the growth evaluation, three different feeding regimes allocated for tilapia juveniles including 0, 10, 20 and 50 ppm concentrations of HK L-137 for the first 50-day feeding period, and then fish were continuously fed diets with reduced HK L-137 levels of 0, 2, 4 and 4 ppm, respectively for 70 days, and finally the last feeding period prolonged for 30 days without HK L-137 in diets. In terms of the immunity test, fish were exposed to ammonium chloride and Streptococcus agalactiae to investigate the immune responses and stress resistance.Fish fed HK L-137 containing diets showed significantly higher growth compared to those fed the control diet. Phagocyte and lysozyme activity of fish fed HK L-137 diets were significantly higher than those of the control for 50-day feeding period and a similar situation obtained at day 75 for fish fed 4 ppm HK L-137-containing diets compared to those of the remaining diets (0 and 2 ppm HK L-137). Stress resistance in fish to ammonia indicated that fish fed HK L-137 supplemented diets performed a lower increment of cortisol concentration compared to those fed the control diet. Interestingly, the lowest cumulative mortality rate (78.33%) obtained in fish fed 20 ppm HK L-137 while the poorest values observed in group fed control diet (96.67%) after exposure to S. agalactiae for 15 days. The present study revealed that the appropriate doses of HK L-137 ranged from 20 to 50 ppm in diets provided the notable positive effects enhancing not only the growth performances but also immunity responses and stress resistance of Nile tilapia.

Anti-inflammatory effects of heat-killed Lactobacillus plantarum L-137 on cardiac and adipose tissue in rats with metabolic syndrome

The effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on chronic inflammation associated with metabolic disorders have remained unknown. We examined the effects of HK L-137 on cardiac and adipose tissue pathophysiology in DahlS.Z-Leprfa/Leprfa (DS/obese) rats as a model of metabolic syndrome. DS/obese rats were treated orally with HK L-137 (2 or 75 mg kg−1 day−1) from 9 to 13 weeks of age. HK L-137 attenuated left ventricular (LV) inflammation and fibrosis as well as adipocyte hypertrophy, inflammation, and up-regulation of sterol regulatory element–binding protein–1c (SREBP-1c) gene expression in visceral and subcutaneous adipose tissue, without affecting body weight gain or hypertension. The low dose of HK L-137 also ameliorated LV diastolic dysfunction, the increase in subcutaneous fat mass, and insulin resistance as well as attenuated the down-regulation of Akt phosphorylation in visceral and subcutaneous adipose tissue, and the elevation of the circulating interleukin-6 concentration. Furthermore, the proportion of regulatory T (Treg) cells among CD4+ T cells in the spleen was increased by HK L-137. These results suggest that the anti-inflammatory effects of HK L-137 on the heart and adipose tissue are related, at least partly, to suppression of systemic inflammation associated with an increase in splenic Treg cell.

Effects of dietary heat-killedLactobacillus plantarumL-137 (HK L-137) on the growth performance, digestive enzymes and selected non-specific immune responses in sea cucumber,Apostichopus japonicusSelenka

A feeding trial was conducted to evaluate the efficacy of dietary heat-killed Lactobacillus plantarum L-137 (HK L-137) on growth performance, digestive, non-specific immune and phagocytosis of sea cucumber, Apostichopus japonicus. Sea cucumbers (initial body weight 1.35 ± 0.04 g) were fed diets supplemented with five levels of HK L-137 (0, 0.005, 0.025, 0.05 and 0.25 g HK L-137 kg−1 diets) for 60 days. Results indicated sea cucumbers fed with diets containing 0.05 and 0.25 g HK L-137 kg−1 diets showed significantly (P < 0.05) higher body weight gain and specific growth rate than other groups. Sea cucumbers fed with diets containing 0.05 and 0.25 g HK L-137 kg−1 diets showed significantly (P < 0.05) higher protease activity than control group. Higher amylase, lysozyme and phagocytic activities were found in 0.25 g HK L-137 kg−1 diet group. Higher superoxide dismutase enzyme and alkaline phosphatase activity was found in 0.05 g HK L-137 kg−1. While no significant differences (P > 0.05) were found in acid phosphatase activity. These results suggested that dietary supplementation of 0.05 g HK L-137 kg−1 diets would have benefit on growth, digestive enzymes and several non-specific immune parameters of sea cucumber.

Scavenger receptor for lipoteichoic acid is involved in the potent ability of Lactobacillus plantarum strain L-137 to stimulate production of interleukin-12p40.

Heat-killed Lactobacillus plantarum strain L-137 (HK L-137) is a more potent inducer of interleukin (IL)-12 than other heat-killed Lactobacillus strains. To elucidate the mechanism involved in this IL-12p40 induction, we compared HK L-137 with heat-killed L. plantarum strain JCM1149 (HK JCM1149) by nuclear magnetic resonance and mass spectrometry. Results showed that HK L-137 contained lipoteichoic acid (LTA) with a chemical structure similar to that of JCM1149, except for a lower degree of glucosyl substitution in the poly(glycerol phosphate) backbone. Lysozyme sensitivity and electrophoretic moiety analysis revealed that HK L-137 exposed more LTA on its cell surface than HK JCM1149. Phagocytosis of HK L-137 by splenic adherent cells was significantly greater than that of HK JCM1149. Anti-LTA antibody and anti-scavenger receptor-A (SR-A) antibody selectively inhibited phagocytosis of HK L-137, as well as IL-12p40 production, by splenic adherent cells. Thus, a higher efficiency of phagocytosis of HK L-137 via SR-A for LTA is responsible for the potent IL-12p40 induction.

Oral intake of heat-killed Lactobacillus plantarum L-137 decreases the incidence of upper respiratory tract infection in healthy subjects with high levels of psychological stress.

The immunomodulatory effects of live or non-viable lactic acid bacteria have been extensively investigated. We reported that oral intake of heat-killed Lactobacillus plantarum L-137 (HK L-137) augmented innate and acquired immunity in mice and human subjects. To examine the effects of HK L-137 intake on upper respiratory tract infection (URTI) symptoms and immune functions in human subjects, a randomised, double-blind, placebo-controlled, parallel study was conducted in subjects with high psychological stress levels. A total of seventy-eight healthy subjects (thirty-three men and forty-five women; mean age 50·6 years) with scores of>41 on eighteen-item subscales of psychological distress in the Brief Job Stress Questionnaire were randomly assigned to receive a tablet containing HK L-137 (10mg) or a placebo tablet daily for 12 weeks. The URTI symptoms were rated once daily on the validated twenty-one-item Wisconsin Upper Respiratory Symptom Survey-21. Immune functions, such as concanavalin A-induced proliferation and percentages of interferon (IFN)-γ- and IL-4-producing CD4 T cells of peripheral blood mononuclear cells (PBMC), and serum IFN-β concentrations were measured every 4 weeks. URTI incidence was significantly lower in the HK L-137 group than in the control group. URTI incidence, duration and severity, and duration of medication showed significant negative correlations with duration of HK L-137 intake. The percentage change from baseline of concanavalin A-induced proliferation of PBMC was significantly greater in the HK L-137 group than in the control group. These findings suggest that daily HK L-137 intake can decrease URTI incidence in healthy subjects, possibly through augmentation of immune functions.

Daily intake of heat-killed Lactobacillus plantarum L-137 enhances type I interferon production in healthy humans and pigs

We have previously reported that oral administration of heat-killed Lactobacillus plantarum L-137 (HK L-137) stimulates innate immunity for production of type I interferon (IFN) which subsequently augments host defense against influenza A virus infection in mice. We here examined the effect of HK L-137 intake on type I IFN in humans. Sixteen subjects were randomly assigned to receive a tablet containing 10 mg of HK L-137 or a matching tablet for 8 weeks and the serum levels of type I IFN were examined before and after the first or second dose of the trivalent inactivated influenza vaccine. There were no differences in the seroresponse rate, the seroprotection rate and the geometric mean Ab titers after either the first or second dose of vaccine between the HK L-137 group and the control group. On the other hand, the levels of IFN-β were significantly higher in the HK L-137 group than in the control group before vaccination although the vaccination conferred little additional induction of IFN-β. We further examined IFN-β gene expression in the whole blood cells of pigs fed on a diet containing HK L-137 and found that the IFN-β mRNA levels were significantly higher in the HK L-137 group than in the control group. The finding that daily intake of HK L-137 enhances type I IFN production and host defense against influenza A virus infection in mice may be applied to at least two additional species.