Glucose- and glycaemic factor-lowering effects of probiotics on diabetes: a meta-analysis of randomised placebo-controlled trials. Br J Nutr. 2016;115:1167-1177. [PMID: 26899960 DOI: 10.1017/s0007114516000076]

Probiotics for pancreatic β-cell function: from possible mechanism of action to assessment of effectiveness

Type 2 diabetes (T2D) is a metabolic disease characterized by chronic hyperglycemia because of insulin resistance (IR) and\or pancreatic β-cell dysfunction. Last century research showed that gut microbiota has a direct effect on metabolism and metabolic diseases. New studies into the human microbiome and its connection with the host is making it possible to develop new therapies for a wide variety of diseases. Inflammation is a well-known precursor to metabolic syndrome, which increases the risk of hypertension, visceral obesity, and dyslipidemia, which can lead to T2D through the damage of pancreatic β-cell and reduce insulin secretion. Current understanding for beneficial effects of probiotics in T2D strictly rely on both animal and clinical data, which mostly focused on their impact on IR, anthropometric parameters, glycemic control and markers of chronic systemic inflammation. From the other hand, there is a lack of evidence-based probiotic efficacy on pancreatic β-cell function in terms of T2D and related metabolic disorders. Therefore, current review will focus on the efficacy of probiotics for the protection of β-cells damage and it`s mechanism in patients with T2D.

Gut microbiota interventions in type 2 diabetes mellitus: An umbrella review of glycemic indices

BACKGROUND

We aimed to explore how probiotics, prebiotics, or synbiotics impact glycemic indices in patients with diabetes mellitus.

METHOD

A comprehensive search was conducted on PubMed, Scopus, and Web of Science from inception up to April 2023. The random-effects model was employed for the study analysis. Furthermore, sensitivity and subgroup analyses were conducted to investigate potential sources of heterogeneity. AMSTAR2 checklist was used to determine the quality of studies. Comprehensive meta-analysis version 3 was used for the study analysis.

RESULT

A total of 31 studies were included in the final analysis. Based on the results of the meta-analysis, gut microbial therapy could significantly decrease serum fasting blood glucose levels in patients with type 2 diabetes mellitus (effect size: -0.211; 95 % CI: -0.257, -0.164; P < 0.001). Additionally, significant associations were also found between gut microbial therapy and improved serum levels of fasting insulin, glycated hemoglobin, and homeostatic model assessment for insulin resistance (effect size: -0.087; 95 % confidence interval: -0.120, -0.053; P < 0.001; effect size: -0.166; 95 % confidence interval: -0.200, -0.132; P < 0.001; effect size: -0.230; 95 % confidence interval: -0.288, -0.172; P < 0.001, respectively).

CONCLUSION

Our results revealed promising effects of gut microbiota modulation on glycemic profile of patients with type 2 diabetes mellitus. The use of these agents as additional treatments can be considered.

Beneficial effects of a new probiotic formulation on adipocytokines, appetite-regulating hormones, and metabolic parameters in obese women

Obesity is often accompanied by low-grade chronic inflammation and metabolic syndrome. It has been established that microbiota influences many physiological processes, including the development of obesity, and dysbiosis has been observed in obese individuals. In this study, we aimed to evaluate the impact of a new probiotic formulation, containing two probiotic strains and the bioactive compound octacosanol, on body weight, metabolic parameters, and concentrations of certain adipocytokines and appetite-regulating hormones in obese women. This double blind placebo-controlled supplementary intervention study included twenty-five women in the intervention group and twenty-three in the placebo group, and it lasted 12 weeks. Daily oral supplementation included 7 × 1010 CFU of Lactiplantibacillus plantarum 299v (DSM9843), 5 × 109 CFU of Saccharomyces cerevisiae var. boulardii (DBVPG6763), and 40 mg of octacosanol or placebo. Body weight, metabolic parameters, adipocytokines, and appetite-regulating hormones were assessed before (T0) and after the intervention (T1). After the intervention, significantly lower median concentrations of CRP (p = 0.005) and IL-6 (p = 0.012) were measured in the intervention group than the baseline, while the median concentrations of ghrelin (p = 0.026) and HDL-cholesterol (p = 0.03) were significantly increased. The intervention group had lower CRP levels (p = 0.023) and higher ghrelin levels (p = 0.006) than the placebo group. Significant changes in BMI between groups were not observed. In summary, although the new probiotic formulation showed beneficial effects on IL-6, CRP, HDL, and ghrelin levels, its potential effects on regulating triglyceride, insulin, and glucose levels require further studies before the novel dietary intervention could be considered a useful adjuvant therapy and an effective strategy for the management of obesity and obesity-associated comorbidities.

Human gut microbiome: Therapeutic opportunities for metabolic syndrome-Hype or hope?

Shifts in gut microbiome composition and metabolic disorders are associated with one another. Clinical studies and experimental data suggest a causal relationship, making the gut microbiome an attractive therapeutic goal. Diet, intake of probiotics or prebiotics and faecal microbiome transplantation (FMT) are methods to alter a person's microbiome composition. Although FMT may allow establishing a proof of concept to use microbiome modulation to treat metabolic disorders, studies show mixed results regarding the effects on metabolic parameters as well as on the composition of the microbiome. This review summarizes the current knowledge on diet, probiotics, prebiotics and FMT to treat metabolic diseases, focusing on studies that also report alterations in microbiome composition. Furthermore, clinical trial results on the effects of common drugs used to treat metabolic diseases are synopsized to highlight the bidirectional relationship between the microbiome and metabolic diseases. In conclusion, there is clear evidence that microbiome modulation has the potential to influence metabolic diseases; however, it is not possible to distinguish which intervention is the most successful. In addition, a clear commitment from all stakeholders is necessary to move forward in the direction of developing targeted interventions for microbiome modulation.

Maternal and infant microbiome: next-generation indicators and targets for intergenerational health and nutrition care

Microbes are commonly sensitive to shifts in the physiological and pathological state of their hosts, including mothers and babies. From this perspective, the microbiome may be a good indicator for diseases during pregnancy and has the potential to be used for perinatal health monitoring. This is embodied in the application of microbiome from multi body sites for auxiliary diagnosis, early prediction, prolonged monitoring, and retrospective diagnosis of pregnancy and infant complications, as well as nutrition management and health products developments of mothers and babies. Here we summarized the progress in these areas and explained that the microbiome of different body sites is sensitive to different diseases and their microbial biomarkers may overlap between each other, thus we need to make a diagnosis prudently for those diseases. Based on the microbiome variances and additional anthropometric and physical data, individualized responses of mothers and neonates to meals and probiotics/prebiotics were predictable, which is of importance for precise nutrition and probiotics/prebiotics managements and developments. Although a great deal of encouraging performance was manifested in previous studies, the efficacy could be further improved by combining multi-aspect data such as multi-omics and time series analysis in the future. This review reconceptualizes maternal and infant health from a microbiome perspective, and the knowledge in it may inspire the development of new options for the prevention and treatment of adverse pregnancy outcomes and bring a leap forward in perinatal health care.

Attenuation of Hyperglycemia in Diabetic Rats Assisted by Immobilized Probiotic in Sodium Alginate

Diabetes mellitus type 2 (DM2) is the most common chronic disease worldwide, characterized mainly by increased glucose concentration in the blood and affecting several organs' functionality. The daily consumption of probiotic bacteria can help control diabetes and reduce the damage caused. Cell immobilization techniques are a powerful tool that provides physical cell protection to such probiotic bacteria against gastrointestinal conditions. We suggest that cell immobilization could be a significant vector for delivering a high quantity of viable probiotics to the gut, helping attenuate hyperglycemia in diabetic rats. Seventy male Wistar rats were used in this work. Nicotinamide was administrated via intraperitoneal injection 15 minutes before inducing type 2 diabetes (DM2), followed by a second intraperitoneal injection of streptozotocin to induce DM2. Rats were divided into seven groups. For 45 days, a specific treatment was applied to each group. The group of rats, supplied with immobilized Lactobacillus casei, showed a serum glucose concentration of 137 mg/dL, which was close to the one observed in the groups of healthy rats (117 mg/dL) and rats treated with metformin (155 mg/dL). The diabetic rats without treatment presented a higher serum glucose concentration (461 mg/dL). In the rats treated with immobilized L. casei, there was no biochemical parameter alteration, and the cell morphology of the analyzed tissues was similar to those of the healthy group. The consumption of immobilized L. casei could allow a high quantity of viable probiotics to be delivered to the gut, reducing serum glucose concentration by up to 70% compared to diabetic rats and reducing organ damage caused by diabetes.

The effects of pro-, pre-, and synbiotics supplementation on polycystic ovary syndrome: an umbrella review of meta-analyses of randomized controlled trials

Background

Synbiotics, refer to a combination of probiotics and prebiotics in a form of synergism that beneficially affect the host's health by alternating the composition and/or function of the gut microbiota. Numerous meta-analyses of randomized clinical trials have proven that pro, pre-, and synbiotics supplementation has health outcomes in women with polycystic ovary syndrome (PCOS). However, the strength and quality of this evidence in aggregate have not yet been synthesized in great detail.

Methods

PubMed, Scopus, Web of Sciences, and Google Scholar were searched up to March 2023. We pooled the mean difference and its 95% confidence interval (CI) by applying a random-effects model.

Results

Overall, nine meta-analyses including a total of 12 trials were identified. The results of the present study indicated that probiotic supplementation significantly reduced the homeostatic model assessment for insulin resistance (HOMA-IR; WMD: -0.29, 95% CI: -0.57 to -0.02, p = 0.03, n = 4; moderate certainty) and fasting glucose concentration (FGC; WMD: -7.5 mg/dL, 95% CI: -13.60 to -0.51, p = 0.03; n = 4; low certainty). Moreover, synbiotic supplementation had beneficial effects on glycemic control, lipid profile, and hormonal parameters, but the certainty of the evidence was rated as low to very low. However, supplementation with pro-/synbiotics did not affect inflammation and oxidative stress in women with PCOS. Furthermore, waist/hip circumference, fasting glucose concentration, lipid profile, dehydroepiandrosterone sulfate, high-sensitivity C-reactive protein, and hirsutism score were significantly reduced after prebiotics supplementation with low certainty of evidence.

Conclusion

Although pro-, pre-, and synbiotics supplementation had beneficial effects on some PCOS-related outcomes, the certainty of the evidence was rated as low to very low. Therefore, further well-designed RCTs might help to confirm our findings in women with PCOS.

Benefits of Combining Sonchus brachyotus DC. Extracts and Synbiotics in Alleviating Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease, commonly abbreviated to NAFLD, is a pervasive ailment within the digestive system, exhibiting a rising prevalence, and impacting individuals at increasingly younger ages. Those afflicted by NAFLD face a heightened vulnerability to the onset of profound liver fibrosis, cardiovascular complications, and malignancies. Currently, NAFLD poses a significant threat to human health, and there is no approved therapeutic treatment for it. Recent studies have shown that synbiotics, which regulate intestinal microecology, can positively impact glucolipid metabolism, and improve NAFLD-related indicators. Sonchus brachyotus DC., a Chinese herb, exhibits hepatoprotective and potent antioxidant properties, suggesting its potential therapeutic use in NAFLD. Our preclinical animal model investigation suggests that the synergy between Sonchus brachyotus DC. extracts and synbiotics is significantly more effective in preventing and treating NAFLD, compared to the isolated use of either component. As a result, this combination holds the potential to introduce a fresh and encouraging therapeutic approach to addressing NAFLD.

American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update

OBJECTIVE

The objective of this clinical practice guideline is to provide updated and new evidence-based recommendations for the comprehensive care of persons with diabetes mellitus to clinicians, diabetes-care teams, other health care professionals and stakeholders, and individuals with diabetes and their caregivers.

METHODS

The American Association of Clinical Endocrinology selected a task force of medical experts and staff who updated and assessed clinical questions and recommendations from the prior 2015 version of this guideline and conducted literature searches for relevant scientific papers published from January 1, 2015, through May 15, 2022. Selected studies from results of literature searches composed the evidence base to update 2015 recommendations as well as to develop new recommendations based on review of clinical evidence, current practice, expertise, and consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RESULTS

This guideline includes 170 updated and new evidence-based clinical practice recommendations for the comprehensive care of persons with diabetes. Recommendations are divided into four sections: (1) screening, diagnosis, glycemic targets, and glycemic monitoring; (2) comorbidities and complications, including obesity and management with lifestyle, nutrition, and bariatric surgery, hypertension, dyslipidemia, retinopathy, neuropathy, diabetic kidney disease, and cardiovascular disease; (3) management of prediabetes, type 2 diabetes with antihyperglycemic pharmacotherapy and glycemic targets, type 1 diabetes with insulin therapy, hypoglycemia, hospitalized persons, and women with diabetes in pregnancy; (4) education and new topics regarding diabetes and infertility, nutritional supplements, secondary diabetes, social determinants of health, and virtual care, as well as updated recommendations on cancer risk, nonpharmacologic components of pediatric care plans, depression, education and team approach, occupational risk, role of sleep medicine, and vaccinations in persons with diabetes.

CONCLUSIONS

This updated clinical practice guideline provides evidence-based recommendations to assist with person-centered, team-based clinical decision-making to improve the care of persons with diabetes mellitus.

Probiotic therapy, a novel and efficient adjuvant approach to improve glycemic status: An umbrella meta-analysis

BACKGROUND

Probiotics exert several promoting effects on the glycemic status, however, the results of meta-analyses are inconsistent. we conducted an umbrella meta-analysis, across existing systematic reviews and meta-analyses of clinical trials to determine the definite effects of supplementation with probiotics on glycemic indices.

METHODS

A comprehensive systematic search of PubMed/Medline, Scopus, EMBASE, and Web of Science was carried out till August 2021. The random-effects model was employed to conduct meta-analysis. Meta-analysis studies of randomized clinical trials examining the impacts of probiotics supplementation on glycemic indices were qualified in the current umbrella meta-analysis.

RESULTS

48 articles out of 693 in the literature search qualified for inclusion in the umbrella meta-analysis. Pooled effects of probiotics on fasting plasma glucose (FPG), hemoglobin A1C (HbA1c), homeostatic model assessment for insulin resistance (HOMA-IR), and insulin levels were reported in articles 45, 21, 35, and 33, respectively. The analysis indicated a significant decrease of FPG (ES= -0.51 mg/dL; 95% CI: -0.63, -0.38, p < 0.001), HbA1c (ES = -0.32 mg/dL; 95% CI: -0.44, -0.20, p < 0.001), HOMA-IR (ES= -0.56; 95% CI: -0.66, -0.47, p < 0.001), and insulin levels (ES= -1.09 IU/mL; 95% CI: -1.37, -0.81, p = 0.006) by probiotics supplementation.

CONCLUSION

Probiotics have amending effects on FPG, HbA1c, HOMA-IR, and insulin levels. A < 8-week period of probiotic supplementation in the moderate dosages (10⁸ or 10⁹ CFU) is an efficacious approach in improving glycemic parameters. Overall, probiotics could be recommended as an adjuvant anti-hyperglycemic agent.

Synbiotics and Gut Microbiota: New Perspectives in the Treatment of Type 2 Diabetes Mellitus

The number of people with type 2 diabetes mellitus (T2DM) has increased sharply over the past decades. Apart from genetic predisposition, which may cause some of the diagnosed cases, an unhealthy diet and lifestyle are incentive triggers of this global epidemic. Consumption of probiotics and prebiotics to gain health benefits has become increasingly accepted by the public in recent years, and their critical roles in alleviating T2DM symptoms are confirmed by accumulating studies. Microbiome research reveals gut colonization by probiotics and their impacts on the host, while oral intake of prebiotics may stimulate existing metabolisms in the colon. The use of synbiotics (a combination of prebiotics and probiotics) can thus show a synergistic effect on T2DM through modulating the gastrointestinal microenvironment. This review summarizes the research progress in the treatment of T2DM from the perspective of synbiotics and gut microbiota and provides a class of synbiotics which are composed of lactulose, arabinose, and Lactobacillus plantarum, and can effectively adjust the blood glucose, blood lipid, and body weight of T2DM patients to ideal levels.

Probiotic Mechanisms Affecting Glucose Homeostasis: A Scoping Review

The maintenance of a healthy status depends on the coexistence between the host organism and the microbiota. Early studies have already focused on the nutritional properties of probiotics, which may also contribute to the structural changes in the gut microbiota, thereby affecting host metabolism and homeostasis. Maintaining homeostasis in the body is therefore crucial and is reflected at all levels, including that of glucose, a simple sugar molecule that is an essential fuel for normal cellular function. Despite numerous clinical studies that have shown the effect of various probiotics on glucose and its homeostasis, knowledge about the exact function of their mechanism is still scarce. The aim of our review was to select in vivo and in vitro studies in English published in the last eleven years dealing with the effects of probiotics on glucose metabolism and its homeostasis. In this context, diverse probiotic effects at different organ levels were highlighted, summarizing their potential mechanisms to influence glucose metabolism and its homeostasis. Variations in results due to different methodological approaches were discussed, as well as limitations, especially in in vivo studies. Further studies on the interactions between probiotics, host microorganisms and their immunity are needed.

Anti-obesity properties of probiotics; a considerable medical nutrition intervention: Findings from an umbrella meta-analysis

Although several studies have indicated that consumption of probiotics is effective in the treatment of obesity, the results in this regard have yielded controversial findings. The current umbrella meta-analysis was performed to evaluate the effects of probiotics supplementation on obesity indices in adults. Scopus, PubMed, Web of Science, Embase and Google Scholar were searched for relevant studies published till November 2021. Meta-analysis was conducted using the random-effects model. Sensitivity and subgroup analyses were performed. In total, 29 meta-analyses with 14,366 participants, including 112, 78, and 38 unique trials for body mass index (BMI), body weight (BW), and waist circumference (WC), were included in the study, respectively. The findings demonstrated that the probiotics supplementation was significantly effective on decreasing of BMI (ES = -0.21; 95% CI: -0.30, -0.13, p < 0.001; I² = 83.0%, p < 0.001), BW (ES = -0.38, 95% CI: -0.60, -0.16; p < 0.001; I² = 81.8%, p < 0.001), and WC (ES = -0.60; 95% CI: -0.89, -0.31; p < 0.001; I² = 89.1%, p < 0.001). Greater effects on BW were observed when intervention duration was >8 weeks and on obese individuals. BMI was also greatly modified in participants with metabolic syndrome and when intervention duration lasted for ≥12 weeks. The methodological quality (AMSTAR2) was moderate in 83%, low in 10%, and critically low in 7% of included studies. The current umbrella meta-analysis indicated that supplementation of probiotics in adults led to a meaningful reduction in BW, BMI, and WC. Therefore, our findings strongly recommend supplementation with probiotics as a potent intervention in the management of obesity.

A randomised controlled trial of a probiotic and a prebiotic examining metabolic and mental health outcomes in adults with pre-diabetes

AIMS

To evaluate the effect of the probiotic Lactobacillus rhamnosus HN001 and/or cereal enriched with oat-derived beta-glucan (OBG) on metabolic and mental health outcomes when administered to adults with pre-diabetes.

DESIGN

2×2 factorial design randomised, parallel-groups placebo-controlled; double-blinded for probiotic, single-blinded for cereals.

PARTICIPANTS

Community-dwelling adults aged 18-80 years with pre-diabetes: glycated haemoglobin (HbA_1c) 41-49 mmol/mol.

INTERVENTIONS

Capsules containing Lactobacillus rhamnosus (HN001) (6×10⁹ colony-forming units/day), or placebo capsules; and cereal containing 4 g/day OBG or calorie-matched control cereal, taken daily, for 6 months. Study groups were: (A) HN001 capsules+OBG cereal; (B) HN001 capsules+control cereal; (C) placebo capsules+OBG cereal and (D) placebo capsules+control cereal.

OUTCOME MEASURES

Primary outcome: HbA_1c at 6 months.

SECONDARY OUTCOMES

fasting plasma glucose, fasting insulin, homeostatic model assessment of insulin resistance, fasting lipids, blood pressure, body weight, waist circumference, body mass index and mental well-being.

RESULTS

153 participants were randomised. There was complete HbA_1c outcome data available for 129 participants. At 6 months the mean (SD) HbA_1c was 45.9 (4.4) mmol/mol, n=66 for HN001, and 46.7 (4.3) mmol/mol, n=63 for placebo capsules; 46.5 (4.0) mmol/mol, n=67 for OBG and 46.0 (4.6) mmol/mol n=62 for control cereal. The estimated difference between HN001-placebo capsules was -0.83, 95% CI -1.93 to 0.27 mmol/mol, p=0.63, and between OBG-control cereals -0.17, 95% CI -1.28 to 0.94 mmol/mol, p=0.76. There was no significant interaction between treatments p=0.79. There were no differences between groups or significant interactions between treatments for any of the secondary outcomes.

CONCLUSIONS

This study found no evidence of clinical benefit from the supplementation with either HN001 and/or cereal containing 4 g OBG on HbA_1c and all secondary outcomes relevant to adults with pre-diabetes.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clincial Trials Registry number ACTRN12617000990325.

Gut microbiota-derived short chain fatty acids are potential mediators in gut inflammation

Gut inflammation is a challenging concern in humans and animals, which disturbs normal growth and leads to severe bowel diseases. Short chain fatty acids (SCFA) are the gut microbiota metabolites produced from fermentation of non-digestible carbohydrates, and have been reported to modulate gut inflammation. SCFA have been implicated as the potential therapeutic bioactive molecules for gut inflammatory diseases, and could be an alternative to antibiotic growth promoters (AGP). In this review, the existing knowledge about the types of SCFA, the related gut microbes producing SCFA, the roles of SCFA in maintaining gut homeostasis, and how SCFA modulate gut inflammation is summarized. The therapeutic application of SCFA in the treatment of inflammatory bowel disease (IBD) is also highlighted.

Antidiabetic Effects of Pediococcus acidilactici pA1c on HFD-Induced Mice

Prediabetes (PreD), which is associated with impaired glucose tolerance and fasting blood glucose, is a potential risk factor for type 2 diabetes mellitus (T2D). Growing evidence suggests the role of the gastrointestinal microbiota in both PreD and T2D, which opens the possibility for a novel nutritional approach, based on probiotics, for improving glucose regulation and delaying disease progression of PreD to T2D. In this light, the present study aimed to assess the antidiabetic properties of Pediococcus acidilactici (pA1c) in a murine model of high-fat diet (HFD)-induced T2D. For that purpose, C57BL/6 mice were given HFD enriched with either probiotic (1 × 10¹⁰ CFU/day) or placebo for 12 weeks. We determined body weight, fasting blood glucose, glucose tolerance, HOMA-IR and HOMA-β index, C-peptide, GLP-1, leptin, and lipid profile. We also measured hepatic gene expression (G6P, PEPCK, GCK, IL-1β, and IL-6) and examined pancreatic and intestinal histology (% of GLP-1⁺ cells, % of goblet cells and villus length). We found that pA1c supplementation significantly attenuated body weight gain, mitigated glucose dysregulation by reducing fasting blood glucose levels, glucose tolerance test, leptin levels, and insulin resistance, increased C-peptide and GLP-1 levels, enhanced pancreatic function, and improved intestinal histology. These findings indicate that pA1c improved HFD-induced T2D derived insulin resistance and intestinal histology, as well as protected from body weight increase. Together, our study proposes that pA1c may be a promising new dietary management strategy to improve metabolic disorders in PreD and T2D.

Assessing the drug resistance profiles of oral probiotic lozenges

Background

Probiotic lozenges have been developed to harvest the benefits of probiotics for oral health, but their long-term consumption may encourage the transfer of resistance genes from probiotics to commensals, and eventually to disease-causing bacteria.

Aim

To screen commercial probiotic lozenges for resistance to antibiotics, characterize the resistance determinants, and examine their transferability in vitro.

Results

Probiotics of all lozenges were resistant to glycopeptide, sulfonamide, and penicillin antibiotics, while some were resistant to aminoglycosides and cephalosporins. High minimum inhibitory concentrations (MICs) were detected for streptomycin (>128 µg/mL) and chloramphenicol (> 512 µg/mL) for all probiotics but only one was resistant to piperacillin (MIC = 32 µg/mL). PCR analysis detected erythromycin (erm(T), ermB or mefA) and fluoroquinolone (parC or gyr(A)) resistance genes in some lozenges although there were no resistant phenotypes. The dfrD, cat-TC, vatE, aadE, vanX, and aph(3")-III or ant(2")-I genes conferring resistance to trimethoprim, chloramphenicol, quinupristin/dalfopristin, vancomycin, and streptomycin, respectively, were detected in resistant probiotics. The rifampicin resistance gene rpoB was also present. We found no conjugal transfer of streptomycin resistance genes in our co-incubation experiments.

Conclusion

Our study represents the first antibiotic resistance profiling of probiotics from oral lozenges, thus highlighting the health risk especially in the prevailing threat of drug resistance globally.

Characteristics of the Gut Microbiota and Potential Effects of Probiotic Supplements in Individuals with Type 2 Diabetes mellitus

The increasing prevalence of type 2 diabetes mellitus (T2DM) worldwide has become a burden to healthcare systems. In 2019, around 463 million adults were living with diabetes mellitus, and T2DM accounted for 90 to 95% of cases. The relationship between the gut microbiota and T2DM has been explored with the advent of metagenomic techniques. Genome-wide association studies evaluating the microbiota of these individuals have pointed to taxonomic, functional, and microbial metabolite imbalances and represent a potential intervention in T2DM management. Several microbial metabolites and components, such as imidazole propionate, trimethylamine, and lipopolysaccharides, appear to impair insulin signaling, while short-chain fatty acids, secondary bile acids, and tryptophan metabolites may improve it. In addition, the use of probiotics with the aim of transiently restoring the microbial balance or reducing the effects of microbial metabolites that impair insulin sensitivity has been explored. Herein, we critically review the available literature on the changes in the gut microbiota in T2DM together with potential adjuvant therapies that may improve the health status of this population.

Therapeutic Potential of Butyrate for Treatment of Type 2 Diabetes

Metagenomics studies have shown that type 2 diabetes (T2D) is associated with an altered gut microbiota. Whereas different microbiota patterns have been observed in independent human cohorts, reduction of butyrate-producing bacteria has consistently been found in individuals with T2D, as well as in those with prediabetes. Butyrate is produced in the large intestine by microbial fermentations, particularly of dietary fiber, and serves as primary fuel for colonocytes. It also acts as histone deacetylase inhibitor and ligand to G-protein coupled receptors, affecting cellular signaling in target cells, such as enteroendocrine cells. Therefore, butyrate has become an attractive drug target for T2D, and treatment strategies have been devised to increase its intestinal levels, for example by supplementation of butyrate-producing bacteria and dietary fiber, or through fecal microbiota transplant (FMT). In this review, we provide an overview of current literature indicating that these strategies have yielded encouraging results and short-term benefits in humans, but long-term improvements of glycemic control have not been reported so far. Further studies are required to find effective approaches to restore butyrate-producing bacteria and butyrate levels in the human gut, and to investigate their impact on glucose regulation in T2D.

Gut Microbiota and Type 2 Diabetes Mellitus: Association, Mechanism, and Translational Applications

Gut microbiota has attracted widespread attention due to its crucial role in disease pathophysiology, including type 2 diabetes mellitus (T2DM). Metabolites and bacterial components of gut microbiota affect the initiation and progression of T2DM by regulating inflammation, immunity, and metabolism. Short-chain fatty acids, secondary bile acid, imidazole propionate, branched-chain amino acids, and lipopolysaccharide are the main molecules related to T2DM. Many studies have investigated the role of gut microbiota in T2DM, particularly those butyrate-producing bacteria. Increasing evidence has demonstrated that fecal microbiota transplantation and probiotic capsules are useful strategies in preventing diabetes. In this review, we aim to elucidate the complex association between gut microbiota and T2DM inflammation, metabolism, and immune disorders, the underlying mechanisms, and translational applications of gut microbiota. This review will provide novel insight into developing individualized therapy for T2DM patients based on gut microbiota immunometabolism.

Effects of probiotics on body adiposity and cardiovascular risk markers in individuals with overweight and obesity: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Evidence suggests that gut microbiota is a potential factor in the pathophysiology of both obesity and related metabolic disorders. While individual randomized controlled trials (RCTs) have evaluated the effects of probiotics on adiposity and cardiovascular disease (CVD) risk factors in subjects with overweight and obesity, the results are inconsistent. Thus, this systematic review and meta-analysis aimed to evaluate the effects of probiotic supplementation on body weight, body adiposity and CVD risk markers in overweight and obese subjects.

METHODS

A systematic search for RCTs published up to December 2020 was conducted in MEDLINE (via PubMed), EMBASE, Scopus and LILACS. Meta-analysis using a random-effects model was chosen to analyze the impact of combined trials.

RESULTS

Twenty-six RCTs (n = 1720) were included. Data pooling showed a significant effect of probiotics in reducing body weight (MD:-0.70 kg; 95%CI:-1.04,-0.35 kg; P < 0.0001), body mass index (BMI) (MD:-0.24 kg/m²; 95%CI:-0.35,-0.12 kg/m²; P = 0.0001), waist circumference (WC) (MD:-1.13 cm; 95%CI:-1.54,-0.73 cm; P < 0.0001), fat mass (MD:-0.71 kg; 95%CI:-1.10,-0.32 kg; P = 0.0004), tumor necrosis factor-α (MD:-0.16 pg/ml; 95%CI:-0.24,-0.08 pg/ml; P = 0.0001), insulin (MD:-0.85mcU/ml; 95%CI:-1.50,-0.21mcU/ml; P = 0.010), total cholesterol (MD:-0.16 mmol/l; 95%CI:-0.26,-0.05 mmol/l; P = 0.003) and LDL (MD:-0.09 mmol/l; 95%CI:-0.16,-0.03 mmol/l; P = 0.006) compared with control groups. There was a significant decrease in body weight, BMI and WC in studies using both single and multi-bacterial species. Decreases in body adiposity parameters were only observed in studies using a probiotic dose of ≥ 10¹⁰ CFU and for ≥8 weeks duration.

CONCLUSIONS

The present meta-analysis suggests that probiotics consumption may be helpful for improving body weight, body adiposity and some CVD risk markers in individuals with overweight and obesity. The review was registered on PROSPERO (International prospective register of systematic reviews): CRD42020183136.

Effects of probiotic supplementation on anthropometric and metabolic characteristics in adults with metabolic syndrome: A systematic review and meta-analysis of randomized clinical trials

AIMS

We conducted a systematic review and meta-analysis to evaluate evidence from randomized controlled trials (RCTs) documenting the effectiveness of supplementation with pro-/synbiotics versus placebo controls on anthropometric and metabolic (glucoregulatory status, lipid profile) indices in adults with metabolic syndrome (MetS).

METHODS

Databases of MEDLINE, Scopus, Embase, Web of Science, and Cochrane Library were searched through March 2020 to identify eligible RCTs evaluating the effects of pro-/synbiotic consumption in adults (≥18 years) with MetS. Mean differences (MDs) and 95% confidence intervals (CIs) were pooled using random-effects models.

RESULTS

Ten eligible publications (9 RCTs, n = 344 participants) were included. Supplementation with pro-/synbiotics reduced total cholesterol (TC) in adults with MetS versus placebo (MD: -6.66 mg/dL, 95% CI: -13.25 to -0.07, P = 0.04, I² = 28.8%, n = 7), without affecting weight, body mass index, waist circumference, fasting blood sugar, homeostasis model assessment for insulin resistance, insulin, triglyceride, low-density lipoprotein cholesterol, or high-density lipoprotein cholesterol (P > 0.05).

CONCLUSIONS

Pro-/synbiotic consumption may be beneficial in reducing TC levels in adults with MetS. However, our observations do not support the effectiveness of pro-/synbiotics consumption on other anthropometric or metabolic outcomes of MetS. Further investigations with larger sample sizes are required to confirm these findings.

Metabolites Linking the Gut Microbiome with Risk for Type 2 Diabetes

PURPOSE OF REVIEW

An increasing body of evidence suggests that the gut microbiome influences the pathogenesis of insulin resistance and type 2 diabetes (T2D). In this review, we will discuss the latest findings regarding the mechanisms linking the gut microbiome and microbial metabolites with T2D and therapeutic approaches based on the gut microbiota for the prevention and treatment of T2D.

RECENT FINDINGS

Alterations in the gut microbial composition are associated with the risk of T2D. The gut microbiota can metabolize dietary- and host-derived factors to produce numerous microbial metabolites, which are involved in metabolic processes modulating nutrition and energy harvest, gut barrier function, systemic inflammation, and glucose metabolism. Microbial metabolites are important mediators of microbial-host crosstalk impacting host glucose metabolism. Furthermore, microbiome-based interventions may have beneficial effects on glycemic control. Future research is required to develop personalized T2D therapy based on microbial composition and/or metabolites.

Recent advances in the therapeutic application of short-chain fatty acids (SCFAs): An updated review

Over the past decade, the gut microbiota has emerged as an important frontier in understanding the human body's homeostasis and the development of diseases. Gut flora in human beings regulates various metabolic functionalities, including enzymes, amino acid synthesis, bio-transformation of bile acid, fermentation of non-digestible carbohydrates (NDCs), generation of indoles and polyamines (PAs), and production of short-chain fatty acids (SCFAs). Among all the metabolites produced by gut microbiota, SCFAs, the final product of fermentation of dietary fibers by gut microbiota, receive lots of attention from scientists due to their pharmacological and physiological characteristics. However, the molecular mechanisms underlying the role of SCFAs in the interaction between diet, gut microbiota, and host energy metabolism is still needed in-depth research. This review highlights the recent biotechnological advances in applying SCFAs as important metabolites to treat various diseases and maintain colonic health.

Unravelling the involvement of gut microbiota in type 2 diabetes mellitus

Type 2 diabetes mellitus is the most prevalent metabolic disorder characterized by hyperglycemia, hyperlipidemia as well as insulin resistance and is affecting the lives of a huge population across the globe. Genetic mutations, obesity and lack of physical activity constitute the possible factors that can lead to onset and progression of this disorder. However, there is another major factor that can be the root cause of type 2 diabetes mellitus and that is an imbalance in the microorganisms that inhabit the gut. The gut microbiome is a vital component that needs to be given significant attention because any "dysbiosis" in the colonic microorganisms can transform the host from a state of health to a state of disease. This transformation is quite obvious since the gut barrier integrity, host metabolism such as sensitivity to insulin and maintaining blood glucose level are carried out by the tiny organisms inhabiting our intestine. In fact, the normal functioning of the human body is accredited to the microbes, particularly the bacteria, because they generate their metabolites that communicate with host cells and maintain normal physiology. Giving importance to gut health is, therefore, necessary to prevent metabolic diseases that can be maintained by the intake of prebiotics, probiotics, synbiotics along with healthy diet. The tiny microorganisms in the gut that keep our body free of disorders such as type 2 diabetes mellitus need to be in a state of 'eubiosis', else the consequences of disturbance in gut microbes can progress to serious complications in the host.

Clostridium tyrobutyricum Protects against LPS-Induced Colonic Inflammation via IL-22 Signaling in Mice

This study aimed to investigate the effects of Clostridium tyrobutyricum (C. tyrobutyricum) on colonic immunity and the role of IL-22 in the protective function of C. tyrobutyricum. Mice were supplemented with 108 CFU/mL C. tyrobutyricum daily for 20 days, followed by injecting with LPS for 24 h. In vivo interference of IL-22 via injecting with an adeno-associated virus was conducted to elucidate the role of IL-22 in C. tyrobutyricum attenuating colonic inflammation. The results showed that C. tyrobutyricum decreased the mRNA expression of IL-6 and IL-1β. C. tyrobutyricum enhanced the mRNA expression of IL-22 and the expression of MUC2 in the colon. The in vivo interference results showed that C. tyrobutyricum enhanced the mRNA expression of IL-6 and IL-1β while decreased the expression of MUC2 after knocking down IL-22. The flow cytometric analysis showed that C. tyrobutyricum decreased the proportions of macrophages, DCs, and mast cells and effectively regulated the proportion of Th17 cells, indicating that C. tyrobutyricum may stimulate the expression of IL-22 via regulating Th17 cells. Our study concluded that C. tyrobutyricum protected against LPS-induced colonic barrier dysfunction and inflammation via IL-22 signaling, suggesting that C. tyrobutyricum could be a potential probiotic in regulating colonic health.

The role of the gut microbiome and its metabolites in metabolic diseases

It is well known that an unhealthy lifestyle is a major risk factor for metabolic diseases, while in recent years, accumulating evidence has demonstrated that the gut microbiome and its metabolites also play a crucial role in the onset and development of many metabolic diseases, including obesity, type 2 diabetes, nonalcoholic fatty liver disease, cardiovascular disease and so on. Numerous microorganisms dwell in the gastrointestinal tract, which is a key interface for energy acquisition and can metabolize dietary nutrients into many bioactive substances, thus acting as a link between the gut microbiome and its host. The gut microbiome is shaped by host genetics, immune responses and dietary factors. The metabolic and immune potential of the gut microbiome determines its significance in host health and diseases. Therefore, targeting the gut microbiome and relevant metabolic pathways would be effective therapeutic treatments for many metabolic diseases in the near future. This review will summarize information about the role of the gut microbiome in organism metabolism and the relationship between gut microbiome-derived metabolites and the pathogenesis of many metabolic diseases. Furthermore, recent advances in improving metabolic diseases by regulating the gut microbiome will be discussed.

In vitro antidiabetic potentials, antioxidant activities and phytochemical profile of african black pepper (Piper guineense)

Background

Diabetes mellitus is a metabolic disorder of glucose metabolism and management of blood glucose level is the hallmark in the treatment of this disease. The present study investigated chemical composition, in vitro antioxidant and antidiabetic activity of different fractions of 80% methanol Piper guineense leaves extract.

Materials and methods

The crude methanolic extract of P. guineense was obtained following 80% methanol cold extraction and was successively partitioned with dichloromethane (DCM), ethyl acetate (EtOAc), n-butanol (nBuOH) and aqueous solvents to give four fractions. The chemical composition of the fractions from P. guineense was determined using gas chromatography coupled with mass spectrometry (GC-MS) and their potentials as antioxidant and anti-diabetes were evaluated.

Results

The percentage yields were 3.16, 2.22, 0.68 and 0.66% (w/w) in n-butanol, DCM, aqueous and ethyl acetate fractions of P. guineense methanolic extract, respectively. The GC-MS analyses identified a total of 71 and 34 phytochemicals in n-butanol and ethyl acetate fractions respectively. Tributyl acetylcitrate (10.95%) and phytol (9.11%) were the major components in the n-butanol fraction while ethyl piperonyl cyanoacetate (27.35%) and phytol (15.17%) were the major constituents in the ethyl acetate fraction. Ethyl acetate fraction had the highest ferric reducing antioxidant power with a value of 53.96 ± 0.40 mgAAE/g while n-butanol fraction possessed highest total antioxidant power (9.98 ± 0.15) followed by aqueous fraction (9.72 ± 0.02). The ethyl acetate and n-butanol fractions with IC50 value of 0.24 ± 0.07 and 0.83 ± 0.15 μg/mL respectively elicited significant inhibitory activities against α-glucosidase while only n-butanol fraction (IC50 = 0.33 ± 0.09 μg/ml) exhibited appreciable inhibition against α-amylase activity. However, none of the four fractions showed significant inhibitory activity towards dipeptidyl-peptidase-IV.

Conclusion

n-butanol and ethyl acetate fractions of 80% methanol P. guineense leaves extract can be a potential source of bioactive compounds of pharmacological importance in the management of diabetes.

Angiotensin-(1-7) Expressed From Lactobacillus Bacteria Protect Diabetic Retina in Mice

Purpose

A multitude of animal studies substantiates the beneficial effects of Ang-(1-7), a peptide hormone in the protective axis of the renin angiotensin system, in diabetes and its associated complications including diabetic retinopathy (DR). However, the clinical application of Ang-(1-7) is limited due to unfavorable pharmacological properties. As emerging evidence implicates gut dysbiosis in pathogenesis of diabetes and supports beneficial effects of probiotics, we sought to develop probiotics-based expression and delivery system to enhance Ang-(1-7) and evaluate the efficacy of engineered probiotics expressing Ang-(1-7) in attenuation of DR in animal models.

Methods

Ang-(1-7) was expressed in the Lactobacillus species as a secreted fusion protein with a trans-epithelial carrier to allow uptake into circulation. To evaluate the effects of Ang-(1-7) expressed from Lactobacillus paracasei (LP), adult diabetic eNOS-/- and Akita mice were orally gavaged with either 1 × 109 CFU of LP secreting Ang-(1-7) (LP-A), LP alone or vehicle, 3 times/week, for 8 and 12 weeks, respectively.

Results

Ang-(1-7) is efficiently expressed from different Lactobacillus species and secreted into circulation in mice fed with LP-A. Oral administration of LP-A significantly reduced diabetes-induced loss of retinal vascular capillaries. LP-A treatment also prevented loss of retinal ganglion cells, and significantly decreased retinal inflammatory cytokine expression in both diabetic eNOS-/- and Akita mice.

Conclusions

These results provide proof-of-concept for feasibility and efficacy of using engineered probiotic species as live vector for delivery of Ang-(1-7) with enhanced bioavailability.

Translational Relevance

Probiotics-based delivery of Ang-(1-7) may hold important therapeutic potential for the treatment of DR and other diabetic complications.

Gut Microbiota as a Trigger for Metabolic Inflammation in Obesity and Type 2 Diabetes

The gut microbiota has been linked to the development of obesity and type 2 diabetes (T2D). The underlying mechanisms as to how intestinal microbiota may contribute to T2D are only partly understood. It becomes progressively clear that T2D is characterized by a chronic state of low-grade inflammation, which has been linked to the development of insulin resistance. Here, we review the current evidence that intestinal microbiota, and the metabolites they produce, could drive the development of insulin resistance in obesity and T2D, possibly by initiating an inflammatory response. First, we will summarize major findings about immunological and gut microbial changes in these metabolic diseases. Next, we will give a detailed view on how gut microbial changes have been implicated in low-grade inflammation. Lastly, we will critically discuss clinical studies that focus on the interaction between gut microbiota and the immune system in metabolic disease. Overall, there is strong evidence that the tripartite interaction between gut microbiota, host immune system and metabolism is a critical partaker in the pathophysiology of obesity and T2D.

Efficacy of probiotic supplementation in patients with diabetic nephropathy: A systematic review and meta-analysis

BACKGROUND

Diabetic nephropathy (DN) is one of the diabetes mellitus complications, which develops in approximately one-third of diabetic patients. Probiotics are microorganisms such as Lactobacillus and Bifidobacterium which have some benefits with gastrointestinal disorders and diabetic patients.

AIM

We aim to assess the efficacy of probiotic supplementation in patients with diabetic nephropathy (DN).

METHODS

We searched PubMed, Scopus, Web of Science, and Cochrane on 20 august 2019 and updated the search on 26 April 2020 using relevant keywords. Studies were screened for eligibility. We extracted the data from the relevant articles and then these data were pooled as mean difference (MD) with a 95% confidence interval (CI), using Review Manager software (ver. 3.5).

RESULTS

Pooled data from four trials compared probiotics with a placebo showed a significant reduction in insulin (MD = -1.99, 95% CI [-3.99, 0.01]) and Homeostatic Model Assessment for Insulin Resistance (MD = -3.87, 95% CI [-7.51, -0.22]), High-sensitivity C-reactive protein (MD = -1.55, 95% CI [-2.19, -0.92]), malondialdehyde (MD = -0.77, 95% CI [-0.96, -0.58]), sodium (MD = -0.93, 95% CI [-1.87, -0.01]), but the total antioxidant capacity was significantly increased (MD = 62.29, 95% CI [18.34, 106.24]), while no significant effect on other lipid profiles, oxidative stress biomarkers or kidney function parameters like creatinine and glomerular filtration rate. Two trials showed that probiotic soy is better than conventional soy in terms of kidney function and lipid profiles.

CONCLUSION

Probiotics supplementation decreases serum insulin and insulin resistance, but it has no beneficial effect regarding kidney function, body-weight, and lipid profiles, with a moderate positive effect regarding some oxidative stress biomarkers. Also, probiotic soy protein may improve kidney function and lipid profiles. Further studies are needed to confirm our findings and to assess the long-term effect.

Effect of Lactobacillus delbrueckii Subsp. lactis PTCC1057 on Serum Glucose, Fetuin-A ,and Sestrin 3 Levels in Streptozotocin-Induced Diabetic Mice

Intake of probiotic bacteria may improve or preserve insulin sensitivity. Fetuin-A and sestrin 3 have emerged as promising candidate biomarkers for crucial roles in insulin signaling pathway. Therefore, the effect of oral supplementation with the probiotic bacterium Lactobacillus delbrueckii subsp. lactis PTCC1057 on proteins involved in insulin signaling pathway was investigated in normal and streptozotocin (STZ)-induced diabetic mice. The 6-8-week-old female mice were divided into a non-diabetic control, diabetic control, and diabetic experimental and non-diabetic experimental groups (5 mice each group). Diabetic and non-diabetic experimental groups treated with 3 × 10⁷ CFU mL^-1 L. delbrueckii subsp. lactis PTCC1057 by gavage feeding approach daily for 28 days. Serum glucose, fetuin-A, and sestrin 3 levels were measured by standard methods. The result showed that oral administration of L. delbrueckii significantly decreased serum glucose in comparison to diabetic control group (P = 0.01). Serum fetuin-A level was higher in diabetic control group than non-diabetic group and oral administration of L. delbrueckii subsp. lactis PTCC1057 significantly decreased fetuin-A level in diabetic experimental group in comparison with non-diabetic groups (P = 0.001). Sestrin 3 level significantly was lower in diabetic control group than non-diabetic control group (P = 0.03) and it significantly increased in diabetic experimental group in comparison with diabetic control group after intervention of L. delbrueckii subsp. lactis PTCC1057 (P = 0.02). The results show that feeding the STZ-induced diabetic mice with L. delbrueckii subsp. lactis PTCC1057 terminated to decrease in fasting blood glucose and fetuin-A level and increase in serum sestrin 3 level. Therefore, the L. delbrueckii subsp. lactis PTCC1057 can be considered as excellent candidate for future studies on diabetes mellitus.

The Effects of Probiotic Honey Consumption on Metabolic Status in Patients with Diabetic Nephropathy: a Randomized, Double-Blind, Controlled Trial

To the best of our knowledge, this study is the first evaluating the effects of probiotic honey intake on glycemic control, lipid profiles, biomarkers of inflammation, and oxidative stress in patients with diabetic nephropathy (DN). This investigation was conducted to evaluate the effects of probiotic honey intake on metabolic status in patients with DN. This randomized, double-blind, controlled clinical trial was performed among 60 patients with DN. Patients were randomly allocated into two groups to receive either 25 g/day probiotic honey containing a viable and heat-resistant probiotic Bacillus coagulans T11 (IBRC-M10791) (10⁸ CFU/g) or 25 g/day control honey (n = 30 each group) for 12 weeks. Fasting blood samples were taken at baseline and 12 weeks after supplementation to quantify glycemic status, lipid concentrations, biomarkers of inflammation, and oxidative stress. After 12 weeks of intervention, patients who received probiotic honey compared with the control honey had significantly decreased serum insulin levels (- 1.2 ± 1.8 vs. - 0.1 ± 1.3 μIU/mL, P = 0.004) and homeostasis model of assessment-estimated insulin resistance (- 0.5 ± 0.6 vs. 0.003 ± 0.4, P = 0.002) and significantly improved quantitative insulin sensitivity check index (+ 0.005 ± 0.009 vs. - 0.0007 ± 0.005, P = 0.004). Additionally, compared with the control honey, probiotic honey intake has resulted in a significant reduction in total-/HDL-cholesterol (- 0.2 ± 0.5 vs. + 0.1 ± 0.1, P = 0.04). Probiotic honey intake significantly reduced serum high-sensitivity C-reactive protein (hs-CRP) (- 1.9 ± 2.4 vs. - 0.2 ± 2.7 mg/L, P = 0.01) and plasma malondialdehyde (MDA) levels (- 0.1 ± 0.6 vs. + 0.6 ± 1.0 μmol/L, P = 0.002) compared with the control honey. Probiotic honey intake had no significant effects on other metabolic profiles compared with the control honey. Overall, findings from the current study demonstrated that probiotic honey consumption for 12 weeks among DN patients had beneficial effects on insulin metabolism, total-/HDL-cholesterol, serum hs-CRP, and plasma MDA levels, but did not affect other metabolic profiles. http://www.irct.ir: IRCT201705035623N115.

Preclinical relevance of probiotics in type 2 diabetes: A systematic review

Type 2 diabetes (T2DM) is among the most prevalent metabolic diseases in the world and may result in several long-term complications. The crosstalk between gut microbiota and host metabolism is closely related to T2DM. Currently, fragmented data hamper defining the relationship between probiotics and T2DM. This systematic review aimed at investigating the effects of probiotics on T2DM in animal models. We systematically reviewed preclinical evidences using PubMed/MEDLINE and Scopus databases, recovering 24 original articles published until September 27th, 2019. This systematic review was performed according to PRISMA guidelines. We included experimental studies with animal models reporting the effects of probiotics on T2DM. Studies were sorted by characteristics of publications, animal models, performed analyses, probiotic used and interventions. Bias analysis and methodological quality assessments were examined through the SYRCLE's Risk of Bias tool. Probiotics improved T2DM in 96% of the studies. Most studies (96%) used Lactobacillus strains, and all of them led to improved glycaemia. All studies used rodents as models, and male animals were preferred over females. Results suggest that probiotics have a beneficial effect in T2DM animals and could be used as a supporting alternative in the disease treatment. Considering a detailed evaluation of the reporting and methodological quality, the current preclinical evidence is at high risk of bias. We hope that our critical analysis will be useful in mitigating the sources of bias in further studies.

Interactions of probiotics and prebiotics with the gut microbiota

The gut microbiota (GM) composition varies among individuals and is influenced by intrinsic (genetics, age) and extrinsic (environment, diet, lifestyle) factors. An imbalance or dysbiosis is directly associated with the development of several illnesses, due to the potential increase in intestinal permeability leading to a systemic inflammation triggered by higher levels of circulating lipopolysaccharides and changes in the immune response caused by an overgrowth of a specific genus or of pathogens. These mechanisms may increase symptoms in gastrointestinal disorders or reduce glucose tolerance in metabolic diseases. Diet also has a significant impact on GM, and functional foods, namely prebiotics and probiotics, are a novel approach to reestablish the indigenous microbiota. Prebiotics, like inulin and polyphenols, are selectively utilized by GM, releasing short-chain fatty acids (SCFA) and other metabolites which may reduce the intestinal lumen pH, inhibit growth of pathogens, and enhance mineral and vitamin bioavailability. Probiotic microorganism may increase the microbial diversity of GM and improve the integrity of the intestinal barrier, leading to an improvement of baseline and pathologic inflammation. In this chapter, we will discuss the potential roles of prebiotics and probiotics in health and diseases throughout an individual's lifetime and proposed mechanisms of action.

Whey and Its Derivatives for Probiotics, Prebiotics, Synbiotics, and Functional Foods: a Critical Review

The purpose of this review is to highlight the importance of whey as a source of new-generation functional ingredients. Particular interest is given to probiotic growth in the presence of whey derivatives such as lactulose, a lactose derivative, which is a highly sought-after prebiotic in functional feeding. The role of sugar/nitrogen interactions in the formation of Maillard products is also highlighted. These compounds are known for their antioxidant power. The role of bioactive peptides from whey is also discussed in this study. Finally, the importance of an integrated valuation of whey is discussed with an emphasis on functional nutrition and the role of probiotics in the development of novel foods such as synbiotics.

Probiotics, prebiotics, and synbiotics supplementation in prediabetes: protocol for a systematic review and meta-analysis

BACKGROUND

The prevalence of prediabetes and diabetes is increasing rapidly, and 5% to 10% of prediabetic patients will develop diabetes every year. Diabetes causes major health problems as well as a large economic burden. Human studies have demonstrated the beneficial effects of probiotics, prebiotics, and synbiotics supplementation in prediabetes. However, there are no systematic reviews that explore the therapeutic efficacy of probiotics, prebiotics, and synbiotics supplementation in patients with prediabetes. Therefore, we aim to synthesize the existing evidence evaluating the effectiveness and safety of probiotics, prebiotics, and synbiotics supplementation in prediabetic patients.

METHODS

We will search PubMed, EMBASE, Cochrane Library, Web of Science, the Clinical Trials.gov website, China National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang Data Knowledge Service Platform from inception to August 2020. Additionally, the search will be conducted in multiple languages. Search terms are keywords and medical subject headings related to prediabetes, probiotics, prebiotics, and synbiotics. The primary outcomes are differences in glycated hemoglobin and fasting blood glucose. The secondary outcomes are differences in fasting insulin, homeostasis model assessment of insulin resistance, quantitative insulin sensitivity check index, and adverse events. The meta-analysis will be performed using the Revman5.3.0 software provided by the Cochrane Collaboration.

RESULTS

Our study will systematically evaluate the effectiveness and safety of probiotics, prebiotics, and synbiotics supplementation in prediabetes.

CONCLUSION

The findings of this study will provide the best available evidence for probiotics, prebiotics, and synbiotics in the treatment of prediabetes, and provide a strong basis for clinical treatment.

From role of gut microbiota to microbial-based therapies in type 2-diabetes

The incidence of type 2 diabetes mellitus (T2DM) has increased dramatically at an alarming level around the world.T2DM is associated with changeable risk factors in lifestyle as well as genetic and family associated risk factors. More importantly, imbalanced or impaired gut microbial distribution (dysbiosis) has been reported as a contributing risk factor in insulin resistance progression in T2DM. Dysbiosis may restructure the metabolic and functional pathways in the intestine which are involved in the development of T2DM. However, several studies have indicated the constructive and helpful effect of prebiotics, probiotics, and fecal microbiota transplantation (FMT) on the improvement of gut microbiota (GM) and accordingly host metabolism. In this review, the association between GM and T2DM have been evaluated and the role of prebiotics, probiotics and FMT, as potential therapeutic approaches have been discussed. Relevant studies were obtained randomly from online databases such as PubMed/Medline and ISI Web of Science.

Probiotics for the treatment of type 2 diabetes: A review of randomized controlled trials

With the increasing prevalence of type 2 diabetes mellitus (T2DM), there is increased interest in probiotic supplementation for improving glycaemic control. This review evaluates nine randomized controlled trials that tested the effects of probiotics on glycaemic outcomes including fasting plasma glucose, fasting plasma insulin, haemoglobin A1c, and homeostatic model assessment of insulin resistance among adults with T2DM. Based on the evidence reviewed, multistrain probiotics that contain seven million to 100 billion colony forming units of Lactobacillus acidophilus, Streptococcus thermophilus, Lactobacillus bulgaricus, and/or Bifidobacterium lactis administered for 6 to 12 weeks may be efficacious for improving glycaemic control in adults with T2DM. Further research is needed to understand the role of the gut microbiota and the probiotic dose, medium, and duration of exposure that is most effective for disease management.

Effects of Cognitive Behavioral Therapy-Based Intervention on Improving Glycaemic, Psychological, and Physiological Outcomes in Adult Patients With Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Patients with diabetes mellitus (DM) have a high risk of secondary physiological and psychological complications. Some interventions based on cognitive behavioral therapy (CBT) have been used to control glucose levels and improve negative emotions of patients with DM. This study was undertaken to provide an overview of the effectiveness of CBT-based interventions for improving glycaemic control, psychological, and physiological outcomes in adult patients with DM.

METHODS

Randomized controlled trials (RCTs) published in English and Chinese during 2007 and April 2019 were searched through various electronic databases including PubMed, Cochrane Library, Scopus, Embase, ProQuest Dissertations and Theses, and the Chinese databases (WanFang data and China National Knowledge Infrastructure). The primary outcome variables included glycated haemoglobin (HbA1c), fasting plasma glucose (FPG), depression, and anxiety symptoms. The secondary outcomes were weight and cholesterol. Effect sizes were pooled by random-effects modelling using Comprehensive Meta-Analysis software. Physiotherapy Evidence Database tool was used to assess the quality of all included studies.

RESULTS

Twenty-three RCTs comprising 2,619 patients with DM (type 1 and type 2) were included in at least one meta-analysis. The results of the main analysis showed that CBT-based interventions had a better effect on reduced HbA1c (-0.275%, 95% CI: -0.443 to -0.107; p < 0.01) with Hedge's g of 0.466 (95% CI: 0.710 - 0.189), reduced depression symptoms with average reduction of -2.788 (95% CI: -4.450 to -1.207; p < 0.01) and Hedge's g of 0.966 (95% CI: 1.507 - 0.426). Twenty-three RCTs comprising 2,619 patients with DM (type 1 and type 2) were included in this meta-analysis. Several mediators of the effect were found through subgroup analysis for HbA1c and depression symptoms. The interventions emphasising completion homework assignments, stress management, and that used an interpersonal strategy delivered via a group had a better effect on both HbA1c and depression symptoms. In addition, behavioral strategies had a better effect on glycaemic control, and cognitive strategies had a better effect on depression symptoms. There was no difference in the change of FPG, anxiety symptoms, weight, and high-density lipoprotein cholesterol (HDL-C) between CBT-based interventions and the control conditions.

CONCLUSIONS

The findings indicate that CBT-based interventions are effective for improving glycaemic control and depression symptoms in adult patients with type 1 DM (T1DM) or type 2 DM (T2DM) with moderate to large effect size. The results of the subgroup analysis suggest that it is necessary to adopt different types and technical components of CBT according to the population and purpose of the treatment in clinical practice. Due to the high heterogeneity of included studies and other limitations, further study including large number of studies is needed to confirm these results.

Effects of a multispecies synbiotic on glucose metabolism, lipid marker, gut microbiome composition, gut permeability, and quality of life in diabesity: a randomized, double-blind, placebo-controlled pilot study

Purpose

Diabesity, the combination of obesity and type 2 diabetes, is an ever-growing global health burden. Diabesity-associated dysbiosis of the intestinal microbiome has gained attention as a potential driver of disease and, therefore, a possible therapeutic target by means of pro- or prebiotic supplementation. This study tested the effects of a multispecies synbiotic (i.e. a combination of probiotics and prebiotics) on glucose metabolism, gut microbiota, gut permeability, neutrophil function and quality of life in treatment-experienced diabesity patients.

Methods

A randomized, double-blind, placebo-controlled pilot study with 26 diabesity patients was conducted in which patients received a daily dose of a multispecies probiotic and a prebiotic (or a placebo) for 6 months.

Results

There were no changes in glucose metabolism or mixed meal tolerance test responses throughout the study. The analysis of secondary outcomes revealed beneficial effects on hip circumference [− 1 (95% CI − 4; 3) vs +3 (− 1; 8) cm, synbiotics vs. placebo, respectively, p = 0.04], serum zonulin [− 0.04 (− 0.2; 0.1) vs +0.3 (− 0.05; 0.6) ng/ml, p = 0.004)] and the physical role item of the SF36 quality of life assessment [+ 5.4 (− 1.7; 12.5) vs − 5.0 (− 10.1; 0.2) points, p = 0.02] after 3 months of intervention, and lipoprotein (a) [− 2.1 (− 5.7; 1.6) vs +3.4 (− 0.9; 7.9) mg/dl, p = 0.02] after 6 months. There were no significant differences in alpha or beta diversity of the microbiome between groups or time points.

Conclusions

Glucose metabolism as the primary outcome was unchanged during the intervention with a multispecies synbiotic in patients with diabesity. Nevertheless, synbiotics improved some symptoms and biomarkers of type 2 diabetes and aspects of quality of life suggesting a potential role as adjuvant tool in the management of diabesity.

Graphic abstract

Electronic supplementary material

The online version of this article (10.1007/s00394-019-02135-w) contains supplementary material, which is available to authorized users.

Probiotic and synbiotic supplementation could improve metabolic syndrome in prediabetic adults: A randomized controlled trial

AIMS

Modulation of the gastrointestinal microbiome is suggested to contribute to the progression of metabolic syndrome associated diseases. This study was designed to assess the effects of probiotics and synbiotics on metabolic syndrome in individuals with prediabetes.

METHODS

120 adults with prediabetes were enrolled in a double-blind, placebo-controlled randomized parallel-group clinical trial. Participants were randomized to a multi-species probiotic or inulin-based synbiotic or placebo. Blood samples and anthropometric measures were collected at baseline, 12 and 24 weeks after treatment. The primary outcome measures were the changes between groups in metabolic syndrome and its components' prevalence.

RESULTS

A significant trend for a reduction in the prevalence of hyperglycemia in probiotic and synbiotic groups (p = 0.01 and 0.005 respectively), and hypertension in probiotic group (p = 0.04) was found. The decreases in metabolic syndrome prevalence were significant after taking probiotic and synbiotic supplementation as compared with placebo (p = 0.02). Also, the prevalence of low HDL-cholesterol level was decreased during the study in the probiotic group compared with placebo (p = 0.02).

CONCLUSIONS

The potential benefits of using probiotic and synbiotic for metabolic syndrome management in prediabetes have been supported by the results in the current study which might provide an important strategy to combat metabolic syndrome-associated diseases.

The role of gut micorbiome in obesity and diabetes

BACKGROUND

Obesity and diabetes became a grooving problem in both adults and children. Many hypotheses concerned agents involved in the excessive weight gain process and it's consequences. Not only genetic or environmental factors, but also intestinal microbiome seems to play a role in the pathophysiology of this phenomenon.

DATA SOURCES

A systematic review was conducted using Pubmed as the medical database source. Studies concerning connection between microbiome and metabolic disorders such as obesity and diabetes from last 10 years were analyzed.

RESULTS

Intestinal bacteria may be involved both in the development of obesity, and its further complications. The pro-inflammatory and immunomodulating effect of dysbiosis are possible triggers of insulin resistance and diabetes. Early interventions aimed at the microbiome, as well as attempts to modify the microbiome at later stages may become new opportunities in the prevention and treatment of obesity and carbohydrate metabolism disorders.

CONCLUSIONS

The gut microbiome has been shown to be an important part of the metabolic processes. The use of probiotic, prebiotics and symbiotics is promising, but requires further investigations to determine the specific metabolic effects of each bacteria strain and substance.

Expression of Human ACE2 in Lactobacillus and Beneficial Effects in Diabetic Retinopathy in Mice

The angiotensin converting enzyme 2 (ACE2) catalyzes the degradation of Angiotensin II (Ang II) to generate Angiotensin-(1-7), which reduces inflammation and oxidative stress stimulated by Ang II. ACE2 has been shown to be protective in cardiovascular and metabolic diseases including diabetes and its complications. However, the challenge for its clinical application is large-scale production of high-quality ACE2 with sufficient target tissue bioavailability. We developed an expression and delivery system based on the use of probiotic species Lactobacillus paracasei (LP) to serve as a live vector for oral delivery of human ACE2. We show that codon-optimized ACE2 can be efficiently expressed in LP. Mice treated with the recombinant LP expressing the secreted ACE2 in fusion with the non-toxic subunit B of cholera toxin, which acts as a carrier to facilitate transmucosal transport, showed increased ACE2 activities in serum and tissues. ACE2-LP administration reduced the number of acellular capillaries, blocked retinal ganglion cell loss, and decreased retinal inflammatory cytokine expression in two mouse models of diabetic retinopathy. These results provide proof of concept for feasibility of using engineered probiotic species as live vector for delivery of human ACE2 with enhanced tissue bioavailability for treating diabetic retinopathy, as well as other diabetic complications.

Implications of Diet and The Gut Microbiome in Neuroinflammatory and Neurodegenerative Diseases

Within the last century, human lifestyle and dietary behaviors have changed dramatically. These changes, especially concerning hygiene, have led to a marked decrease in some diseases, i.e., infectious diseases. However, other diseases that can be attributed to the so-called ‘Western’ lifestyle have increased, i.e., metabolic and cardiovascular disorders. More recently, multifactorial disorders, such as autoimmune and neurodegenerative diseases, have been associated with changes in diet and the gut microbiome. In particular, short chain fatty acid (SCFA)-producing bacteria are of high interest. SCFAs are the main metabolites produced by bacteria and are often reduced in a dysbiotic state, causing an inflammatory environment. Based on advanced technologies, high-resolution investigations of the abundance and composition of the commensal microbiome are now possible. These techniques enable the assessment of the relationship between the gut microbiome, its metabolome and gut-associated immune and neuronal cells. While a growing number of studies have shown the indirect impact of gut metabolites, mediated by alterations of immune-mediated mechanisms, the direct influence of these compounds on cells of the central nervous system needs to be further elucidated. For instance, the SCFA propionic acid (PA) increases the amount of intestine-derived regulatory T cells, which furthermore can positively affect the central nervous system (CNS), e.g., by increasing remyelination. However, the question of if and how PA can directly interact with CNS-resident cells is a matter of debate. In this review, we discuss the impact of an altered microbiome composition in relation to various diseases and discuss how the commensal microbiome is shaped, starting from the beginning of human life.

The Effects of Probiotic Supplementation on Clinical Symptom, Weight Loss, Glycemic Control, Lipid and Hormonal Profiles, Biomarkers of Inflammation, and Oxidative Stress in Women with Polycystic Ovary Syndrome: a Systematic Review and Meta-analysis of Randomized Controlled Trials

The purpose of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to determine the effectiveness of probiotic supplementation on clinical symptoms, weight loss, glycemic control, lipid and hormonal profiles, and biomarkers of inflammation and oxidative stress in women with polycystic ovary syndrome (PCOS). Eligible studies were systematically searched from Cochrane Library, Embase, Medline, and Web of Science databases until January 2019. Cochran (Q) and I-square statistics were used to measure heterogeneity among included studies. Data were pooled by using random-effect model and expressed as standardized mean difference (SMD) with 95% confidence interval (CI). Eleven articles were included in this meta-analysis. Probiotic supplementation significantly decreased weight (SMD - 0.30; 95% CI, - 0.53, - 0.07; P = 0.01), body mass index (BMI) (SMD - 0.29; 95% CI, - 0.54, - 0.03; P = 0.02), fasting plasma glucose (FPG) (SMD - 0.26; 95% CI, - 0.45, - 0.07; P < 0.001), insulin (SMD - 0.52; 95% CI, - 0.81, - 0.24; P < 0.001), homeostatic model assessment for insulin resistance (HOMA-IR) (SMD - 0.53; 95% CI, - 0.79, - 0.26; P < 0.001), triglycerides (SMD - 0.69; 95% CI, - 0.99, - 0.39; P < 0.001), VLDL-cholesterol (SMD - 0.69; 95% CI, - 0.99, - 0.39; P < 0.001), C-reactive protein (CRP) (SMD - 1.26; 95% CI, - 2.14, - 0.37; P < 0.001), malondialdehyde (MDA) (SMD - 0.90; 95% CI, - 1.16, - 0.63; P < 0.001), hirsutism (SMD - 0.58; 95% CI, - 1.01, - 0.16; P < 0.001), and total testosterone levels (SMD - 0.58; 95% CI, - 0.82, - 0.34; P < 0.001), and also increased the quantitative insulin sensitivity check index (QUICKI) (SMD 0.41; 95% CI, 0.11, 0.70; P < 0.01), nitric oxide (NO) (SMD 0.33; 95% CI 0.08, 0.59; P = 0.01), total antioxidant capacity (TAC) (SMD 0.64; 95% CI, 0.38, 0.90; P < 0.001), glutathione (GSH) (SMD 0.26; 95% CI, 0.01, 0.52; P = 0.04), and sex hormone binding globulin (SHBG) levels (SMD 0.46; 95% CI, 0.08, 0.85; P = 0.01). Probiotic supplementation may result in an improvement in weight, BMI, FPG, insulin, HOMA-IR, triglycerides, VLDL-cholesterol, CRP, MDA, hirsutism, total testosterone, QUICKI, NO, TAC, GSH, and SHBG but did not affect dehydroepiandrosterone sulfate levels, and total, LDL, and HDL cholesterol levels in patients with PCOS.