Effect of Lactobacillus casei on the Production of Pro-Inflammatory Markers in Streptozotocin-Induced Diabetic Rats

Exploring the Significance of Gut Microbiota in Diabetes Pathogenesis and Management-A Narrative Review

Type 2 diabetes is a disease with significant health consequences for the individual. Currently, new mechanisms and therapeutic approaches that may affect this disease are being sought. One of them is the association of type 2 diabetes with microbiota. Through the enteric nervous system and the gut-microbiota axis, the microbiota affects the functioning of the body. It has been proven to have a real impact on influencing glucose and lipid metabolism and insulin sensitivity. With dysbiosis, there is increased bacterial translocation through the disrupted intestinal barrier and increased inflammation in the body. In diabetes, the microbiota's composition is altered with, for example, a more abundant class of Betaproteobacteria. The consequences of these disorders are linked to mechanisms involving short-chain fatty acids, branched-chain amino acids, and bacterial lipopolysaccharide, among others. Interventions focusing on the gut microbiota are gaining traction as a promising approach to diabetes management. Studies are currently being conducted on the effects of the supply of probiotics and prebiotics, as well as fecal microbiota transplantation, on the course of diabetes. Further research will allow us to fully develop our knowledge on the subject and possibly best treat and prevent type 2 diabetes.

Fermentation characteristics and prebiotic potential of enzymatically synthesized butyryl-fructooligosaccharides

Existing prebiotics, such as fructo-oligosaccharides (FOSs), can be modified to enhance their functionality or introduce additional functionalities. This study aimed to investigate the fermentation characteristics and prebiotic potential of enzymatically synthesized butyryl-FOSs. The esters were successfully synthesized through the reaction of butyric acid and FOSs using both chemical and enzymatic methods, denoted as A-FOSs and B-FOSs, respectively, for comparative analysis. The esterification degree of each component in A-FOSs was significantly higher than that of B-FOSs. Subsequently, the obtained esters were characterized for their fermentation properties, degradation mode and potential prebiotic effects using an in vitro simulated colonic fermentation model. Enzymes of human gut microbiota were found to preferentially cleave the glycosidic bond to the unit without butyryl group and release the sugars for utilization. A significant increase in butyric acid levels was observed during fermentation after the supplementation of B-FOSs. The 16S rRNA gene sequencing, absolute quantification of microbiota, and selected probiotic strains culture showed that B-FOSs supplementation promoted the growth of beneficial bacteria while reducing harmful ones. These results suggest that B-FOSs hold promise as novel prebiotics, possessing dual functions of modulating gut microbiota and delivering butyric acid to the colon in a targeted manner, ultimately contributing to improved gut health.

Effect of probiotic yogurt consumption on glycemic control and lipid profile in patients with type 2 diabetes mellitus: A randomized controlled trial

BACKGROUND & AIMS

Type 2 diabetes mellitus (T2DM) is a common endocrine disease. Altered gut microbiota (Dysbiosis) is closely associated with development of T2DM. Growing body of evidence hypothesized that probiotics intake may be useful for patients with T2DM. We investigated the effect of probiotic yogurt consumption on glycemic control and lipid profile in patients with T2DM.

METHODS

In this 12-week randomized controlled clinical trial, seventy-two patients with T2DM were randomly assigned to the intervention group (IG) that received 200 g/d probiotic yogurt containing 4.65 × 10⁶ CFU/g Lactobacillus acidophilus and Bifidobacterium lactis) or placebo group (PG) that received 200 g/d conventional yogurt.

RESULTS

We found no difference between two groups in fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol (TC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-c) and low density lipoprotein-cholesterol (LDL-c) after intervention. After adjusting for baseline values of covariate, a significant reduction in HbA1c (mean change: -0.76 ± 1.3 vs. -0.15 ± 1.3; P = 0.01), TC (mean change: -10.61 ± 27.8 vs. -2.97 ± 35.0; P = 0.02) and LDL-c (mean change: -8.62 ± 21.7 vs. 0.02 ± 25.8; P = 0.004) was observed in the IG compared to the PG. In addition, a non-significant trend to reduction was observed in term of FPG (mean change: -19.61 ± 29.1 vs. -4.19 ± 24.2; P = 0.13). TG and HDL-c remained unchanged.

CONCLUSIONS

Probiotic yogurt consumption may be useful for patients with T2DM. More well-designed clinical trials with longer intervention duration are required. Registered on 30 July 2022 at Iranian Registry of Clinical Trials (IRCT20220226054125N1) with URL: https://www.irct.ir/trial/62304.

Gut microbiome and human health: Exploring how the probiotic genus Lactobacillus modulate immune responses

The highest density of microbes resides in human gastrointestinal tract, known as “Gut microbiome”. Of note, the members of the genus Lactobacillus that belong to phyla Firmicutes are the most important probiotic bacteria of the gut microbiome. These gut-residing Lactobacillus species not only communicate with each other but also with the gut epithelial lining to balance the gut barrier integrity, mucosal barrier defence and ameliorate the host immune responses. The human body suffers from several inflammatory diseases affecting the gut, lungs, heart, bone or neural tissues. Mounting evidence supports the significant role of Lactobacillus spp. and their components (such as metabolites, peptidoglycans, and/or surface proteins) in modulatingimmune responses, primarily through exchange of immunological signals between gastrointestinal tract and distant organs. This bidirectional crosstalk which is mediated by Lactobacillus spp. promotes anti-inflammatory response, thereby supporting the improvement of symptoms pertaining to asthma, chronic obstructive pulmonary disease (COPD), neuroinflammatory diseases (such as multiple sclerosis, alzheimer’s disease, parkinson’s disease), cardiovascular diseases, inflammatory bowel disease (IBD) and chronic infections in patients. The metabolic disorders, obesity and diabetes are characterized by a low-grade inflammation. Genus Lactobacillus alleviates metabolic disorders by regulating the oxidative stress response and inflammatory pathways. Osteoporosis is also associated with bone inflammation and resorption. The Lactobacillus spp. and their metabolites act as powerful immune cell controllers and exhibit a regulatory role in bone resorption and formation, supporting bone health. Thus, this review demonstrated the mechanisms and summarized the evidence of the benefit of Lactobacillus spp. in alleviating inflammatory diseases pertaining to different organs from animal and clinical trials. The present narrative review explores in detail the complex interactions between the gut-dwelling Lactobacillus spp. and the immune components in distant organs to promote host’s health.

Goat Milk Improves Glucose Homeostasis via Enhancement of Hepatic and Skeletal Muscle AMP-Activated Protein Kinase Activation and Modulation of Gut Microbiota in Streptozocin-Induced Diabetic Rats

SCOPE

Previously, the metabolic benefits of goat milk consumption in high-fat diet-fed rats are demonstrated. However, the effects are only reported in one animal model and the involvement of gut microbiota is not investigated. The aim of this study is to investigate the effects of goat milk consumption on glucose homeostasis and gut microbiota in streptozocin (STZ)-induced diabetic rats.

METHODS AND RESULTS

STZ-induced diabetic rats are fed with three dosages of goat milk: 2.5, 5, and 10 g kg-1 . Parameters related to glucose homeostasis, hepatic and skeletal muscle AMP-activated protein kinase (AMPK) activation, and gut microbiota are investigated. The dose of 10 g kg-1 exerts more metabolic benefits. Goat milk consumption improves fasting glucose levels, glucose tolerance, insulin sensitivity, and promotes hepatic and skeletal muscle AMPK activation in STZ-injected diabetic rats. Goat milk modulates gut microbiota, increases the relative abundance of Lactobacillus, and augments levels of propionic and butyric acids.

CONCLUSION

This study demonstrates the metabolic benefits of goat milk consumption in STZ-induced diabetic rats, which is consistent with the previous observations in high-fat diet-induced diabetic rats. Furthermore, this study elucidates the modulation of gut microbiota by goat milk, which likely mediates the metabolic effects of goat milk.

Lactobacillus fermentum MCC2759 and MCC2760 Alleviate Inflammation and Intestinal Function in High-Fat Diet-Fed and Streptozotocin-Induced Diabetic Rats

The growing incidence of type 2 diabetes and obesity has become a worldwide crisis with increased socio-economic burden. Changes in lifestyle and food habits resulting in dysbiosis of the gut microbiota and low-grade inflammation are linked to the rising incidence. The aim of this study was to investigate the effects of potential probiotic Lactobacillus fermentum MCC2759 and MCC2760 on intestinal markers of inflammation using a high-fat diet (HFD)-fed model and a streptozotocin (STZ)-induced diabetic model. Lact. fermentum administration showed improved oral glucose tolerance compared with the model controls of HFD (AUC 1518) and STZ (628.8). Plasma insulin levels improved in the Lact. fermentum treated groups of HFD + MCC2759 (129 ± 4.24 pmol/L) and HFD + MCC2760 (151.5 ± 9.19 pmol/L) in HFD study, while in STZ diabetic study, the insulin levels were normalized with Lact. fermentum administration, for D + MCC2759 (120.5 ± 7.77) and D + MCC2760 (138 ± 5.65 pmol/L) groups. The results showed reduction in inflammatory tone in liver, muscle, and adipose tissues of rats in both models with stimulation of anti-inflammatory IL-10 by real-time quantitative polymerase chain reaction. Additionally, the potential probiotic cultures also displayed normalization of markers related to intestinal barrier integrity (ZO-1), TLR-4 receptor, and insulin sensitivity (GLUT-4, GLP-1, adiponectin). Thus, the results suggest that Lact. fermentum could act as potential probiotic for lifestyle-related disorders such as obesity, diabetes, and metabolic syndrome as both prophylactic and adjunct therapies.

Antidiabetic and Hypolipidaemic Action of Finger Millet (Eleusine coracana)-Enriched Probiotic Fermented Milk: An in vivo Rat Study

Research background

Diabetes is a chronic multi-system disease having long term consequences to the health of people suffering from it. This study investigates the role of finger millet (Eleusine coracana)-enriched probiotic fermented milk in alleviating the diabetic complications in streptozotocin-induced diabetic rats.

Experimental approach

The probiotic strain used in the study was Lactobacillus helveticus MTCC 5463. Study comprised six groups each containing 6 Sprague Dawley rats: two controls (nondiabetic and diabetic), and four diabetic groups fed finger millet-enriched probiotic fermented milk, probiotic fermented milk, finger millet flour or metformin (standard drug). Samples were administered orally for four weeks, and parameters associated with diabetic disorders were studied.

Results and conclusions

Oral administration of finger millet-enriched milk significantly (p<0.001) decreased (64.26%) the fasting blood glucose level of diabetic rats compared to metformin (56.43%) and diabetic groups receiving the probiotic fermented milk (18.88%) and finger millet flour (47.14%) after four weeks of treatment. The finger millet-enriched milk significantly ameliorated the diabetic symptoms polyphagia and polydipsia and improved body mass. In diabetic control group, body mass was reduced up to 15.60% at the end of experiment, while in the group receiving the probiotic fermented milk, body mass significantly (p<0.0001) increased by about 5-30%. Significant (p<0.0001) reduction in total cholesterol, triglyceride levels in the groups treated with finger millet flour, finger millet-enriched probiotic fermented milk and probiotic fermented milk was observed compared to diabetic control rats. The probiotic fermented milk enriched with finger millet caused significant (p<0.05) decrease in low-density lipoprotein and very-low-density lipoprotein levels (p<0.0001) and insignificant increase in high-density lipoprotein level. A reversal of altered activities of hepatic marker enzymes aspartate transaminase and alanine transaminase was observed in the group receiving the probiotic milk enriched with finger millet. Histological observations of pancreatic tissues and liver showed that the enriched milk prevents more severe changes in the acinar cells and ameliorated the inflammation and alteration in the liver structure to some extent. Therefore, the finger millet-enriched probiotic fermented milk can be a potential functional food in the management of diabetes.

Novelty and scientific contribution

This is the only paper reporting about the antidiabetic potential of finger millet-enriched milk fermented using probiotic Lactobacillus helveticus MTCC 5463 and Streptococcus thermophilus MTCC 5460. It also shows the synergistic antidiabetic effect of milk and finger millet used in combination, thus offering a novel functional food.

Lactobacillus acidophilus alleviates type 2 diabetes by regulating hepatic glucose, lipid metabolism and gut microbiota in mice

Diabetes, an endocrine and metabolic disorder, has become the third most non-infectious chronic disease that threatens human health. Type 2 diabetes (T2D) accounts for more than 90% of diabetic patients, mainly caused by environmental factors. Lactic acid bacteria (LAB) exhibit several health benefits to the host including regulating glucose and lipid metabolism and improving oxidative stress and inflammatory response. However, the anti-diabetic mechanism of probiotics has not been elucidated clearly. In this study, the anti-diabetic effects of Lactobacillus acidophilus KLDS1.1003 and KLDS1.0901 on T2D mice were assessed. Oral administration of L. acidophilus KLDS1.1003 and KLDS1.0901 for 6 weeks significantly improved the epithelial barrier function, which in turn lowered inflammation cytokines, including IL-8, TNF-α and IL-1β in liver and colon tissue, and prevented liver and colon tissue injuries to some extent. Additionally, L. acidophilus treatment regulated the expression genes that are related to glucose and lipid metabolism. The two tested strains down-regulated the expression of glycogen synthase kinase 3β (GSK-3β), fatty acid synthase (FAS) and sterol regulatory element-binding transcription factor 1c (SREBP-1c), and up-regulated the expression of protein kinase B (Akt). However, L. acidophilus KLDS1.0901 is better for improving T2D than L. acidophilus KLDS1.1003. Further research showed that L. acidophilus KLDS1.0901 supplementation could reshape gut microbiota, increasing short chain fatty acid-producing bacteria (Blautia, Roseburia and Anaerotruncus) and the level of SCFAs and decreasing the relative abundance of Gram-negative bacteria such as Desulfovibrio, Alistipes and Bacteroides. Notably, L. acidophilus KLDS1.0901 treatment restored the structure of gut microbiota similar to the control group. These findings suggested that L. acidophilus KLDS1.0901 might be used as a new type of antidiabetic drug candidate.

Using probiotics for type 2 diabetes mellitus intervention: Advances, questions, and potential

Type 2 diabetes mellitus (T2DM) has become one of the most prevalent diseases on earth and several treatments have been developed. However, the current intervention approaches have not been as effective as expected. One promising supplementary strategy is the use of probiotics through direct or indirect approaches. Probiotics are microbial food cultures conferring health-promoting properties. In this review, we summarized the current theories and mechanisms of T2DM intervention using probiotics and hypothesize that probiotics intervene T2DM during its onsetting, developing, and complicating. For the first time, we comprehensively analyzed T2DM intervention in animal models using both wide-type probiotics in different forms and using recombinant probiotics. Then, probiotic intervention in T2DM patients was reviewed and the main results were compared with that obtained from animal studies. Finally yet importantly, remaining questions that are important such as in which form and in which state, as well as the future potential of probiotic intervention in T2DM were discussed from a perspective of food microbiologists. In conclusion, probiotic intervention in T2DM is promising but there are still many important issues unsolved yet. Critical review of the advances, questions, and potential of probiotic intervention in T2DM promotes the development of this approach for further application in humans.

The effect of probiotic supplementation on glycemic control and lipid profile in patients with type 2 diabetes: A randomized placebo controlled trial

AIMS

The role of gut microbiota in the pathogenesis of diabetes is increasing; this study investigates the effect of multi-strain probiotics on fasting plasma glucose (FPG), plasma insulin and lipid profile among patients.

METHODS

This randomized double blind controlled trial was performed among 60 patients; individuals were randomly assigned into 2 groups of 30 participants in order to take either probiotic supplements or placebo for 6 weeks. The probiotic supplement consisted of 7 viable strains Lactobacillus, Bifidobacterium and Streptococcus. Nutrient intakes were estimated using a 3-day and 24 hour-dietary recall at the beginning and end of study. Fasting blood samples were taken before and after intervention to measure the levels of FPG, plasma insulin and lipid profiles.

RESULTS

Within group comparisons showed significant decrease and increase in the levels of FPG (P = 0.001) and HDL-C (P = 0.002) in probiotic group, respectively. No significant alterations were observed for within and between group comparisons in the levels of insulin, triglycerides, total cholesterol, insulin resistance and anthropometric measurements, including weight, waist circumference and body mass index (all P > 0.05).

CONCLUSIONS

This study showed a significant decrease in FPG level by multi-strain probiotic supplements in within group comparison; though, further studies are needed to confirm results. (IRCT Code: IRCT2013100714925N1).

Adipose tissue inflammation and metabolic syndrome. The proactive role of probiotics

PURPOSE

The first part of this review focuses on the role of cells and molecules of adipose tissue involved in metabolic syndrome-induced inflammation and in the maintenance of this pathology. In the second part of the review, the potential role of probiotics-modulating metabolic syndrome-related inflammatory components is summarized and discussed.

METHODS

The search for the current scientific literature was carried out using ScienceDirect, PubMed, and Google Scholar search engines. The keywords used were: metabolic syndrome, obesity, insulin resistant, adipose tissue, adipose tissue inflammation, chronic low-grade inflammation, immune cells, adipokines, cytokines, probiotics, and gut microbiota.

RESULTS AND CONCLUSIONS

Chronic low-grade inflammation that characterized metabolic syndrome can contribute to the development of the metabolic dysfunctions involved in the pathogenesis of its comorbidities. Adipose tissue is a complex organ that performs metabolic and immune functions. During metabolic syndrome, an imbalance in the inflammatory components of adipose tissue (immune cells, cytokines, and adipocytokines), which shift from an anti-inflammatory to a pro-inflammatory profile, can provoke metabolic syndrome linked complications. Further knowledge concerning the immune function of adipose tissue may contribute to finding better alternatives for the treatment or prevention of such disorders. The control of inflammation could result in the management of many of the pathologies related to metabolic syndrome. Due to the strong evidence that gut microbiota composition plays a role modulating the body weight, adipose tissue, and the prevalence of a low-grade inflammatory status, probiotics emerge as valuable tools for the prevention of metabolic syndrome and health recovery.

Probiotic Lactobacillus casei Shirota improves efficacy of amoxicillin-sulbactam against childhood fast breathing pneumonia in a randomized placebo-controlled double blind clinical study

The aim of the present study was to investigate the efficacy of oral administration of probiotic Lactobacillus casei Shirota and amoxicillin-sulbactam in treating childhood fast breathing pneumonia. 518 children diagnosed of fast breathing pneumonia were enrolled and randomly assigned to be administered either amoxicillin-sulbactam + Lactobacillus casei Shirota or amoxicillin-sulbactam + placebo. Primary outcome was defined as treatment failure before day 3, and secondary outcome was defined as treatment failure during follow-ups on day 6 and 12. Serum levels of tumor necrosis factor-α and interferon-γ were also examined at the end of day 3. Treatment failure rate before day 3 was significantly reduced in amoxicillin-sulbactam + Lactobacillus casei Shirota group compared to amoxicillin-sulbactam + placebo group. Serum levels of tumor necrosis factor-α and interferon-γ were both significantly reduced in amoxicillin-sulbactam + placebo group on day 3. On day 6 and 12, although treatment failure rates were higher than on day 3 in both groups, it was still significantly reduced in amoxicillin-sulbactam + Lactobacillus casei Shirota group. No severe adverse effects were observed in either treatment group. In conclusion, Probiotic Lactobacillus casei Shirota, in combination with amoxicillin-sulbactam, is more effective in treating childhood fast breathing pneumonia, which supports the potential clinical application of Lactobacillus casei Shirota as a safe supplement to amoxicillin-sulbactam therapy against childhood fast breathing pneumonia.

Potential mechanisms linking probiotics to diabetes: a narrative review of the literature

CONTEXT AND OBJECTIVE:

Some studies have suggested a wide range of possible mechanisms through which probiotics may play a role in diabetes prevention and treatment. However, the underlying mechanisms are not fully understood. We conducted this study to review the potential mechanisms suggested for the effect of probiotics in diabetes.

DESIGN AND SETTING:

Narrative review conducted at the Food Security Research Center of Isfahan.

METHODS:

A search in the electronic databases MEDLINE (PubMed), Cochrane Library, Web of Science and Google scholar was performed up to October 2016.

RESULTS:

The initial search yielded 1214 reports. After removing duplicates, 704 titles and abstracts were screened. Finally, out of 83 full-text articles that were reviewed for eligibility, 30 articles were included in the final analysis. The anti-diabetic mechanisms for probiotics reported encompass intraluminal and direct effects on the intestinal mucosa and microbiota (n = 13), anti-inflammatory and immunomodulatory effects (n = 10), antioxidative effects (n = 5), effects on endoplasmic reticulum (ER) stress and expression of genes involved in glucose homeostasis and insulin resistance (n = 6), with some studies pointing to more than one mechanism.

CONCLUSION:

The results may throw some light on the capacity of probiotics as a novel approach towards controlling diabetes. However, further human studies are warranted to elucidate and confirm the potential role of probiotics in diabetes prevention and treatment. Also, it needs to be ascertained whether the effectiveness of probiotics in diabetes prevention and treatment is dependent on the strain of the microorganisms.

Influence of GABA and GABA-producing Lactobacillus brevis DPC 6108 on the development of diabetes in a streptozotocin rat model

The aim of this study was to investigate if dietary administration of γ-aminobutyric acid (GABA)-producing Lactobacillus brevis DPC 6108 and pure GABA exert protective effects against the development of diabetes in streptozotocin (STZ)-induced diabetic Sprague Dawley rats. In a first experiment, healthy rats were divided in 3 groups (n=10/group) receiving placebo, 2.6 mg/kg body weight (bw) pure GABA or L. brevis DPC 6108 (~10(9)microorganisms). In a second experiment, rats (n=15/group) were randomised to five groups and four of these received an injection of STZ to induce type 1 diabetes. Diabetic and non-diabetic controls received placebo [4% (w/v) yeast extract in dH2O], while the other three diabetic groups received one of the following dietary supplements: 2.6 mg/kg bw GABA (low GABA), 200 mg/kg bw GABA (high GABA) or ~10(9) L. brevis DPC 6108. L. brevis DPC 6108 supplementation was associated with increased serum insulin levels (P<0.05), but did not alter other metabolic markers in healthy rats. Diabetes induced by STZ injection decreased body weight (P<0.05), increased intestinal length (P<0.05) and stimulated water and food intake. Insulin was decreased (P<0.05), whereas glucose was increased (P<0.001) in all diabetic groups, compared with non-diabetic controls. A decrease (P<0.01) in glucose levels was observed in diabetic rats receiving L. brevis DPC 6108, compared with diabetic-controls. Both the composition and diversity of the intestinal microbiota were affected by diabetes. Microbial diversity in diabetic rats supplemented with low GABA was not reduced (P>0.05), compared with non-diabetic controls while all other diabetic groups displayed reduced diversity (P<0.05). L. brevis DPC 6108 attenuated hyperglycaemia induced by diabetes but additional studies are needed to understand the mechanisms involved in this reduction.

Probiotics as beneficial agents in the management of diabetes mellitus: a systematic review

Probiotics have been suggested to play an important role in the management of diabetes. We conducted a systematic review on the role of probiotics in modulating parameters related to diabetes in animal and human experiments. We searched Pubmed, Scopus and Cochrane central until June 2014, concerning the effects of probiotics on hyperglycemia, hyperinsulinemia and their anti-diabetic efficacies by modulating the activities of proinflammatory and antioxidant factors. Our initial search retrieved 1120 reports. After screening titles and abstracts, 72 full-text articles were reviewed for eligibility. Ultimately, 33 articles met our inclusion criteria consisting of five human and twenty eight animal reports. Lactobacillus strains were, in particular, used in all studies with or without other strains. We found that probiotics have beneficial effects on glycemic controls, as all human studies showed significant reductions in at least one of the primary outcome endpoints which were the levels of fasting plasma glucose, postprandial blood glucose, glycated haemoglobin, insulin, insulin resistance and onset of diabetes; similarly, all the animal reports, except for two, documented significant changes in these parameters. Regarding secondary outcome measures, that is, lipid profiles, pro-inflammatory and anti-oxidant factors, only one human and one animal study failed to show any significant changes in any of these parameters. This systematic review generally demonstrated beneficial effects of the probiotic administration, especially Lactobacillus sub-strains, on the management of diabetes-related blood parameters, although, more evidence, especially from human trials, is needed to confirm these effects and also to conduct a meta-analysis. Copyright © 2015 John Wiley & Sons, Ltd.

Short communication: Effect of supplementation with Lactobacillus casei Shirota on insulin sensitivity, β-cell function, and markers of endothelial function and inflammation in subjects with metabolic syndrome--a pilot study

Based on animal studies, intake of probiotic bacteria was suggested to improve insulin sensitivity by reducing endotoxinemia and inflammation. The objective of this study was to determine the effects of supplementation with the probiotic strain Lactobacillus casei Shirota (LcS) over 12 wk on insulin sensitivity, β-cell function, inflammation, and endothelial dysfunction parameters in subjects with metabolic syndrome. In a randomized-controlled study, 30 subjects with metabolic syndrome either received Lactobacillus casei Shirota 3 times daily for 12 wk or served as controls with standard medical therapy. Fasting blood samples were taken and a 75-g oral glucose tolerance test was performed to derive indices for insulin sensitivity and β-cell function. In addition, parameters to assess endothelial function and inflammation markers were determined. Even though the insulin sensitivity index significantly improved after 3 mo of probiotic supplementation (0.058±0.021 vs. 0.038±0.025), the change was not significantly different compared with the control group. No improvements were seen in additional indices of insulin sensitivity (quantitative insulin sensitivity check index, insulin sensitivity by oral glucose tolerance test, and homeostasis model assessment for insulin resistance) and β-cell function (first and second phase insulin secretion, and homeostasis model assessment for β-cell function). Probiotic supplementation resulted in a significant reduction in soluble vascular cell adhesion molecule-1 (sVCAM-1) level (1,614±343 vs. 1,418±265 ng/mL). No significant changes in parameters used to assess low-grade inflammation or endothelial dysfunction were observed. Intake of LcS for 12 wk in subjects with metabolic syndrome did not improve insulin sensitivity, β-cell function, endothelial function, or inflammation markers in this trial.