Effect of dietary prebiotic supplementation on advanced glycation, insulin resistance and inflammatory biomarkers in adults with pre-diabetes: a study protocol for a double-blind placebo-controlled randomised crossover clinical trial

Effect of gut hormones on bone metabolism and their possible mechanisms in the treatment of osteoporosis

Bone is a highly dynamic organ that changes with the daily circadian rhythm. During the day, bone resorption is suppressed due to eating, while it increases at night. This circadian rhythm of the skeleton is regulated by gut hormones. Until now, gut hormones that have been found to affect skeletal homeostasis include glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2), glucose-dependent insulinotropic polypeptide (GIP), and peptide YY (PYY), which exerts its effects by binding to its cognate receptors (GLP-1R, GLP-2R, GIPR, and Y1R). Several studies have shown that GLP-1, GLP-2, and GIP all inhibit bone resorption, while GIP also promotes bone formation. Notably, PYY has a strong bone resorption-promoting effect. In addition, gut microbiota (GM) plays an important role in maintaining bone homeostasis. This review outlines the roles of GLP-1, GLP-2, GIP, and PYY in bone metabolism and discusses the roles of gut hormones and the GM in regulating bone homeostasis and their potential mechanisms.

Role of Synbiotics (Prebiotics and Probiotics) as Dietary Supplements in Type 2 Diabetes Mellitus Induced Health Complications

Diabetes is a metabolic disorder whose prevalence has become a worrying condition in recent decades. Chronic diabetes can result in serious health conditions such as impaired kidney function, stroke, blindness, and myocardial infarction. Despite a variety of currently available treatments, cases of diabetes and its complications are on the rise. This review article provides a comprehensive account of the ameliorative effect of prebiotics and probiotics individually or in combination i.e. synbiotics on health complications induced by Type 2 Diabetes Mellitus (T2DM). Recent advances in the field underscore encouraging outcomes suggesting the consumption of synbiotics leads to favorable changes in the gut microbiota. These changes result in the production of bioactive metabolites such as short-chain fatty acids (crucial for lowering blood sugar levels), reducing inflammation, preventing insulin resistance, and encouraging the release of glucagon-like peptide-1 in the host. Notably, novel strategies supplementing synbiotics to support gut microbiota are gaining attraction as pivotal interventions in mitigating T2DM-induced health complications. Thus, by nurturing a symbiotic relationship between prebiotics and probiotics i.e. synbiotics, these interventions hold promise in reshaping the microbial landscape of the gut thereby offering a multifaceted approach to managing T2DM and its associated morbidities. Supporting the potential of synbiotics underscores a paradigm shift toward holistic and targeted interventions in diabetes management, offering prospects for improved outcomes and enhanced quality of life for affected individuals. Nevertheless, more research needs to be done to better understand the single and multispecies pre/pro and synbiotics in the prevention and management of T2DM-induced health complications.

Advanced glycation end products and insulin resistance in diabetic nephropathy

Insulin resistance is a central hallmark that connects the metabolic syndrome and diabetes to the resultant formation of advanced glycation end products (AGEs), which further results in the complications of diabetes, including diabetic nephropathy. Several factors play an important role as an inducer to diabetic nephropathy, and AGEs elicit their harmful effects via interacting with the receptor for AGEs Receptor for AGEs, by induction of pro-inflammatory cytokines, oxidative stress, endoplasmic reticulum stress and fibrosis in the kidney tissues leading to the loss of renal function. Insulin resistance results in the activation of other alternate pathways governed by insulin, which results in the hypertrophy of the renal cells and tissue remodeling. Apart from the glucose uptake and disposal, insulin dependent PI3K and Akt also upregulate the expression of endothelial nitric oxide synthase, that results in increasing the bioavailability of nitric oxide in the vascular endothelium, which further results in tissue fibrosis. Considering the global prevalence of diabetic nephropathy, and the impact of protein glycation, various inhibitors and treatment avenues are being developed, to prevent the progression of diabetic complications. In this chapter, we discuss the role of glycation in insulin resistance and further its impact on the kidney.

Prebiotic Systems Containing Anthocyanin-Rich Pomegranate Flower Extracts with Antioxidant and Antidiabetic Effects

Pomegranate flower extract, rich in anthocyanins, demonstrates beneficial health-promoting properties such as an anti-diabetic and antioxidant effect, among others. However, the potential health-promoting properties may be hindered by the low stability of anthocyanins. Therefore, the aim of our study was to assess whether stabilizing carriers, namely HP-γ-cyclodextrin (HP-γ-CD), α-cyclodextrin (α-CD), Methyl-β-cyclodextrin (Me-β-CD), Inulin (Inu) and Arabic gum (AGu) affect the antioxidant and antidiabetic activity of lyophilized pomegranate flower extract, how they influence stability, release profile, and whether the systems exhibit prebiotic activity. Interactions between pomegranate flower extract and these factors were analyzed using FT-IR. The structures were examined through microscopic imaging while for the prepared prebiotic systems, antidiabetic activity was determined and confirmed by the inhibition of α-amylase and α-glucosidase; antioxidant activity was expressed by DPPH and CUPRAC assays. The content of pelargonidin-3,5-glucoside in these systems was assessed using the HPLC method. The release profiles of pelargonidin-3,5-glucoside were examined in a medium at pH = 6.8 and pH = 1.2, and the stability was assessed after subjecting the systems to high temperatures (T = 90 °C). The prebiotic potential was evaluated for 10 prebiotic bacterial strains (Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus brevis Lactobacillus rhamnosus gg, Lactobacillus reuteri, Pediococcus pentosaceus, Lactococcus lactis, Lactobacillus fermentum lf, Streptococcus thermophilus). As a result of the conducted research, better functionalities of the obtained systems containing Pomegranate flower extract were proven in terms of prebiotic and antidiabetic effects. The obtained delivery systems for pelargonidin-3,5-glucoside allow for better use of its health-promoting effects.

Inulin intake and the incidence of cardiometabolic diseases: a prospective cohort study

Inulin is a prebiotic and has beneficial effects on health, such as improving the immune function, lipid profile, and gut microbiota. Some previous studies have assessed the effects of inulin supplementation on cardiometabolic diseases, but the relationship between dietary inulin and these diseases has not been investigated yet. Thus, this survey was designed to assess the potential association between the dietary intake of inulin and the incidence of cardiometabolic diseases, including cardiovascular disease (CVD), hypertension (HTN), chronic kidney disease (CKD), and type 2 diabetes (T2D) among adults. The present prospective cohort study was conducted on participants in the third wave of the Tehran Lipid and Glucose Study (2006-2008) and was followed up until March 2018. The dietary intake of inulin was estimated using a special database that reports values of inulin and oligofructose in grams per 100 g of each food. Cox proportional hazards regression showed that higher consumption of inulin was associated with a lower risk of HTN (HR: 0.79, 95% CI: 0.63 to 0.99) and T2D (HR: 0.94, 95% CI: 0.89 to 1.00). We found no relationship between higher consumption of dietary inulin and the incidence of CKD and CVD in our population. According to our results, it seems inulin from foods had a preventive effect against HTN and T2D, which are major risk factors for cardiovascular and renal events. However, more investigations are warranted.

The Effect of Adding Job’s Tears to Yogurt on Plasma Glycated Albumin, Weight, and Lipid Profile in Patients with Type 2 Diabetes Mellitus: A Randomized Controlled Trial

Background

A potential effect of Job's tears on metabolic diseases has been recognized. However, studies on the effect of Job's tears on lipid profile and glycated albumin (GA) are still rare. This study aimed to examine the influence of Job's tears in conjunction with probiotics on the lipid profile and GA concentration of patients with type 2 diabetes mellitus.

Methods

This double-blind 12-week study involved 60 patients with type 2 diabetes assigned randomly into two groups. The first group consumed yogurt alone (containing Lactobacillus acidophilus La5 and Bifidobacterium Bb12), while the second had yogurt with Job's tears once daily (200 ml each). Lipids and GA concentrations were measured using an enzymatic colorimetric assay. Paired and unpaired Students t-test, Wilcoxon signed-rank, and Mann–Whitney test were applied. Statistical significance was set at p < 0.05.

Results

The characteristics of the groups were comparable except for baseline plasma GA (p=0.012). Subjects who used Metformin were distributed equally between the groups (p=0.118). Caloric intake between the groups also did not differ (p=0.856). There was also no change in weight, BMI, or plasma GA. Yogurt and the mixture of Job's tears and yogurt reduced cholesterol and LDL and increased HDL (all p < 0.05) within the groups. However, HDL levels in patients who had Job's tears were significantly elevated than yogurt alone (0.9 vs. 25 mg/dL, p=0.029).

Conclusion

The combination of Job's tears and yogurt improved HDL more than yogurt alone.

Advanced Glycation End Products (AGEs) and Chronic Kidney Disease: Does the Modern Diet AGE the Kidney?

Since the 1980s, chronic kidney disease (CKD) affecting all ages has increased by almost 25%. This increase may be partially attributable to lifestyle changes and increased global consumption of a “western” diet, which is typically energy dense, low in fruits and vegetables, and high in animal protein and ultra-processed foods. These modern food trends have led to an increase in the consumption of advanced glycation end products (AGEs) in conjunction with increased metabolic dysfunction, obesity and diabetes, which facilitates production of endogenous AGEs within the body. When in excess, AGEs can be pathological via both receptor-mediated and non-receptor-mediated pathways. The kidney, as a major site for AGE clearance, is particularly vulnerable to AGE-mediated damage and increases in circulating AGEs align with risk of CKD and all-cause mortality. Furthermore, individuals with significant loss of renal function show increased AGE burden, particularly with uraemia, and there is some evidence that AGE lowering via diet or pharmacological inhibition may be beneficial for CKD. This review discusses the pathways that drive AGE formation and regulation within the body. This includes AGE receptor interactions and pathways of AGE-mediated pathology with a focus on the contribution of diet on endogenous AGE production and dietary AGE consumption to these processes. We then analyse the contribution of AGEs to kidney disease, the evidence for dietary AGEs and endogenously produced AGEs in driving pathogenesis in diabetic and non-diabetic kidney disease and the potential for AGE targeted therapies in kidney disease.

The Promising Role of Microbiome Therapy on Biomarkers of Inflammation and Oxidative Stress in Type 2 Diabetes: A Systematic and Narrative Review

Background

One in 10 adults suffer from type 2 diabetes (T2D). The role of the gut microbiome, its homeostasis, and dysbiosis has been investigated with success in the pathogenesis as well as treatment of T2D. There is an increasing volume of literature reporting interventions of pro-, pre-, and synbiotics on T2D patients.

Methods

Studies investigating the effect of pro-, pre-, and synbiotics on biomarkers of inflammation and oxidative stress in T2D populations were extracted from databases such as PubMed, Scopus, Web of Science, Embase, and Cochrane from inception to January 2022.

Results

From an initial screening of 5,984 hits, 47 clinical studies were included. Both statistically significant and non-significant results have been compiled, analyzed, and discussed. We have found various promising pro-, pre-, and synbiotic formulations. Of these, multistrain/multispecies probiotics are found to be more effective than monostrain interventions. Additionally, our findings show resistant dextrin to be the most promising prebiotic, followed closely by inulin and oligosaccharides. Finally, we report that synbiotics have shown excellent effect on markers of oxidative stress and antioxidant enzymes. We further discuss the role of metabolites in the resulting effects in biomarkers and ultimately pathogenesis of T2D, bring attention toward the ability of such nutraceuticals to have significant role in COVID-19 therapy, and finally discuss few ongoing clinical trials and prospects.

Conclusion

Current literature of pro-, pre- and synbiotic administration for T2D therapy is promising and shows many significant results with respect to most markers of inflammation and oxidative stress.

Coffee Chlorogenic Acids Incorporation for Bioactivity Enhancement of Foods: A Review

The demand of foods with high antioxidant capacity have increased and research on these foods continues to grow. This review is focused on chlorogenic acids (CGAs) from green coffee, which is the most abundant source. The main CGA in coffee is 5-O-caffeoylquinic acid (5-CQA). Coffee extracts are currently the most widely used source to enhance the antioxidant activity of foods. Due to the solubility of CGAs, their extraction is mainly performed with organic solvents. CGAs have been associated with health benefits, such as antioxidant, antiviral, antibacterial, anticancer, and anti-inflammatory activity, and others that reduce the risk of cardiovascular diseases, type 2 diabetes, and Alzheimer's disease. However, the biological activities depend on the stability of CGAs, which are sensitive to pH, temperature, and light. The anti-inflammatory activity of 5-CQA is attributed to reducing the proinflammatory activity of cytokines. 5-CQA can negatively affect colon microbiota. An increase in anthocyanins and antioxidant activity was observed when CGAs extracts were added to different food matrices such as dairy products, coffee drinks, chocolate, and bakery products. The fortification of foods with coffee CGAs has the potential to improve the functionality of foods.

Dietary supplementation of inulin alleviates metabolism disorders in gestational diabetes mellitus mice via RENT/AKT/IRS/GLUT4 pathway

BACKGROUND

Gestational diabetes mellitus (GDM) has significant short and long-term health consequences for both the mother and child. There is limited but suggestive evidence that inulin could improve glucose tolerance during pregnancy. This study assessed the effect of inulin on glucose homeostasis and elucidated the molecular mechanisms underlying the inulin-induced antidiabetic effects during pregnancy.

METHOD

Female C57BL/6 mice were randomized to receive either no treatment, high-dose inulin and low-dose inulin for 7 weeks with measurement of biochemical profiles. A real-time² (RT²) profiler polymerase chain reaction (PCR) array involved in glycolipid metabolism was measured.

RESULTS

Inulin treatment facilitated glucose homeostasis in a dose-dependent manner by decreasing fasting blood glucose, advanced glycation end products and total cholesterol, and improving glucose tolerance. Suppressing resistin (RETN) expression was observed in the inulin treatment group and the expression was significantly correlated with fasting blood glucose levels. The ratios of p-IRS to IRS and p-Akt to Akt in liver tissue and the ratio of p-Akt to Akt in adipose tissue as well as the expression level of GLUT4 increased significantly after inulin treatment.

CONCLUSIONS

Our findings indicated improvement of glucose and lipid metabolism by inulin was to activate glucose transport through the translocation of GLUT4 which was mediated by insulin signaling pathway repairment due to decreased expression of RETN and enhanced phosphorylation of IRS and Akt in GDM mice.

Inflammation Parameters Associated with Metabolic Disorders: Relationship Between Diet and Microbiota

The metabolic syndrome (MetS) includes numerous interrelated clinical, anthropometric, biochemical, and metabolic components and has become a public health problem due to its impact on morbimortality. Inflammation is a central mechanism underlying the etiology and clinical manifestations of MetS, contributing to its related pathological outcomes. Dietary patterns have been associated with the promotion of the diversity of microbiota in the digestive tract. Recently, research has focused on the importance of microbiota changes associated with MetS and inflammation. Other studies have been performed to understand the impact of prebiotics, probiotics, and synbiotics as allies on diet, inflammation, and MetS parameters. This review analyses the correlation between metabolic disorders, inflammation parameters, gut microbiota, and how diet has been involved as treatment of MetS and the modulation of inflammation and microbiota.

Anti-inflammatory and -apoptotic effects of a long-term herbal extract treatment on DSS-induced colitis in mice fed with high AGEs-fat diet

Background

Obesity is associated with many comorbidities including inflammatory bowel disease (IBD). We investigated prophylactic effects of an herbal extract (HE) on the DSS-induced colitis mice challenged with high AGEs-fat diet 60% (HFD).

Methods

Six-week-old C57BL/6 male mice were fed with either HFD (8 groups, 6 mice in each group), or normal diet (ND) (8 groups, 6 mice in each group). After 6 weeks, animals received HE (combination of turmeric, ginger, boswellia and cat’s claw extract) for 7 weeks in three doses (high dose (0.6 mg/g); low dose (0.15 mg/g) and mid dose (0.3 mg/g)). Next, mice were subjected to 2.5% DSS in drinking water. Control mice received ND and instead of HE and DSS they received distilled water. Obesity index markers were determined, H&E staining and TUNEL assay evaluated apoptosis. Colonic expressions of IL-6, RAGE, AGER1, Sirt1, Bax, Bcl2, ZO-1 and P53 were determined.

Results

HE ameliorated colitis in HFD mice by reducing colonic myeloperoxidase activity (by 2.3-fold), macrophage accumulation (by 2.6-fold) and mRNA expression of IL-6 (by 2.3-fold) in HFD mice. Moreover, HE restored ZO-1 (by 2.7-fold), prevented apoptosis and maintained immune homeostasis. HE reduced activation of NF-κB protein (by 1.3-fold) through decreasing RAGE (by 1.93-fold) and up-regulation of Sirt1 (by 7.71-fold) and prevented down-regulation of DDOST (by 6.6-fold) in HFD mice.

Conclusions

HE ameliorated colitis in prophylactic in HFD mice and it was, at least partly, due to the restoration of the gut integrity, suppression of inflammation and apoptosis via modulation of colonic Sirt1, RAGE and DDOST signaling.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-021-00603-x.

Co-supplementation of camelina oil and a prebiotic is more effective for in improving cardiometabolic risk factors and mental health in patients with NAFLD: a randomized clinical trial

This trial evaluated the effects of co-supplementing Camelina sativa oil (CSO) and a prebiotic as modulators of the gut microbiota on cardiometabolic risk factors and mental health in NAFLD patients. In all, 44 subjects with NAFLD were allocated to either an intervention (20 g d-1 CSO + resistant dextrin) or a placebo (20 g d-1 CSO + maltodextrin) group and received a calorie-restricted diet (-500 kcal d-1) for 12 weeks. Fasting plasma levels of gucose, insulin, hs-CRP, endotoxin, antioxidant enzyme activity, total antioxidant capacity (TAC), malondialdehyde (MDA), 8-iso-prostaglandin F2α, and uric acid were measured at the baseline and post-intervention. The depression, anxiety and stress scale (DASS) and the general health questionnaire (GHQ) were used to assess mental health. Co-supplementing CSO and resistant dextrin significantly decreased the level of insulin concentration (-0.84 μU ml-1, p = 0.011), HOMA-IR (-0.27, p = 0.021), hs-CRP (-1.25 pg ml-1, p = 0.023), endotoxin (-3.70 EU mL-1, p = 0.001), cortisol (-2.43, p = 0.033), GHQ (-5.03, p = 0.035), DASS (-9.01, p = 0.024), and MDA (-0.54 nmol mL-1, p = 0.021) and increased the levels of TAC (0.16 mmol L-1, p = 0.032) and superoxide dismutase (106.32 U g-1 Hb, p = 0.45) in the intervention group compared with the placebo group. No significant changes were observed in the levels of other biomarkers. Co-supplementing CSO and resistant dextrin in combination with a low-calorie diet may improve metabolic risk factors and mental health in NAFLD patients.

Assessing the effects of inulin-type fructan intake on body weight, blood glucose, and lipid profile: A systematic review and meta-analysis of randomized controlled trials

Inulin-type fructan (ITF) intake has been suggested to alleviate several features of metabolic syndrome including obesity, diabetes, and hyperlipidemia; yet, results from the human trials remained inconsistent. We aimed to systematically evaluate the effects of ITF intake on body weight, glucose homeostasis, and lipid profile on human subjects with different health status, including healthy, overweight and obese, prediabetes and diabetes, and hyperlipidemia. Weighted mean differences (WMDs) between ITF and control groups were calculated by a random-effects model. A total of 33 randomized controlled human trials were included. Significant effect of ITF intake was only observed in the diabetics, but not in the other subject groups. Specifically, ITF intervention significantly decreased the WMD of blood glucose (-0.42 mmol/L; 95% CI: -0.71, -0.14; p = .004), total cholesterol (-0.46 mmol/L; 95% CI: -0.75, -0.17; p = .002), and triglycerides (TAG) (-0.21 mmol/L; 95% CI: -0.37, -0.05; p = .01) compared with the control. The stability of these favorable effects of ITF on diabetics was confirmed by sensitivity analysis. Also, ITF tends to lower LDL cholesterol (p = .084). But body weight and blood insulin were not affected by ITF intake. It should be noted that blood glucose, total cholesterol, and LDL cholesterol exhibited high unexplained heterogeneity. In conclusion, ITF intake lowers blood glucose, total cholesterol, and TAG in the people with diabetes, and they may benefit from addition of inulin into their diets, but the underlying mechanisms responsible for these effects are inconclusive.

Alzheimer's Disease and Diabetes: Role of Diet, Microbiota and Inflammation in Preclinical Models

Alzheimer's disease (AD) is the most common cause of dementia. Epidemiological studies show the association between AD and type 2 diabetes (T2DM), although the mechanisms are not fully understood. Dietary habits and lifestyle, that are risk factors in both diseases, strongly modulate gut microbiota composition. Also, the brain-gut axis plays a relevant role in AD, diabetes and inflammation, through products of bacterial metabolism, like short-chain fatty acids. We provide a comprehensive review of current literature on the relation between dysbiosis, altered inflammatory cytokines profile and microglia in preclinical models of AD, T2DM and models that reproduce both diseases as commonly observed in the clinic. Increased proinflammatory cytokines, such as IL-1β and TNF-α, are widely detected. Microbiome analysis shows alterations in Actinobacteria, Bacteroidetes or Firmicutes phyla, among others. Altered α- and β-diversity is observed in mice depending on genotype, gender and age; therefore, alterations in bacteria taxa highly depend on the models and approaches. We also review the use of pre- and probiotic supplements, that by favoring a healthy microbiome ameliorate AD and T2DM pathologies. Whereas extensive studies have been carried out, further research would be necessary to fully understand the relation between diet, microbiome and inflammation in AD and T2DM.

Inflammatory Activities in Type 2 Diabetes Patients With Co-morbid Angiopathies and Exploring Beneficial Interventions: A Systematic Review

Background: Diabetes is a long-term condition that can be treated and controlled but do not yet have a cure; it could be induced by inflammation and the goal of managing it is to prevent additional co-morbidities and reduce glycemic fluctuations. There is a need to examine inflammatory activities in diabetes-related angiopathies and explore interventions that could reduce the risk for future outcome or ameliorate its effects to provide insights for improved care and management strategies.

Method: The study was conducted in Embase (1946–2020), Ovid Medline (1950–2020), and PubMed databases (1960–2020) using the PICO framework. Primary studies (randomized controlled trials) on type 2 diabetes mellitus and inflammatory activities in diabetes-related angiopathies were included. Terms for the review were retrieved from the Cochrane library and from PROSPERO using its MeSH thesaurus qualifiers. Nine articles out of 454 total hits met the eligibility criteria. The quality assessment for the selected study was done using the Center for Evidence-Based Medicine Critical Appraisal Sheet.

Results: Data analysis showed that elevated CRP, TNF-α, and IL-6 were the most commonly found inflammatory indicator in diabetes-related angiopathies, while increased IL-10 and soluble RAGE was an indicator for better outcome. Use of drugs such as salsalate, pioglitazone, simvastatin, and fenofibrate but not glimepiride or benfotiamine reported a significant decrease in inflammatory events. Regular exercise and consumption of dietary supplements such as ginger, hesperidin which have anti-inflammatory properties, and those containing prebiotic fibers (e.g., raspberries) revealed a consistent significant (p < 0.05) reduction in inflammatory activities.

Conclusion: Inflammatory activities are implicated in diabetes-related angiopathies; regular exercise, the intake of healthy dietary supplements, and medications with anti-inflammatory properties could result in improved protective risk outcome for diabetes patients by suppressing inflammatory activities and elevating anti-inflammatory events.

Glycation of gut proteins initiates microbial dysbiosis and can promote establishment of diabetes in experimental animals

Diabetes and obesity is associated with change in the gut microbiota, however, the reason for such transition is still unknown. The secondary complications in diabetes mainly stem from protein glycation, oxidative stress and inflammatory response. It is intended to study the correlation between gut proteins glycation and microbial dysbiosis and thereby progression to diabetes. The study was carried out through feeding high fructose to male Wistar rats and evaluating their gut microbiota. The rate of gut flora excretion via faecal matter was found to decrease on fructose feed for 7 days. Intestinal flora was drastically reduced and pathogenic succession observed. Intestinal fluorescence studies confirmed that there is heavy glycation of gut proteins. Microbes obtained from fructose fed animals could grow on glycated BSA. There was significant increase in level of TNF-α and IFN-γ providing evidence of inflammation. Though microbial dysbiosis was observed in diabetes, the cause for this remained elusive. In the present study we prove that high fructose feed and glycation of the gut proteins probably prevent adherence/survival of the gut microflora in control animals and promotes transition to a changed microflora which is capable of adhering/utilizing glycated proteins as well as high fructose. The changed microbiota, enhanced protein glycation and inflammation help in establishing insulin resistance.

Effects of High-Fat Diet Induced Obesity and Fructooligosaccharide Supplementation on Cardiac Protein Expression

The mechanism by which high fat-diet induced obesity affects cardiac protein expression is unclear, and the extent to which this is modulated by prebiotic treatment is not known. These outcomes were assessed in rats initially fed a high-fat diet, then the top 40% weight gain group were randomly allocated to control (CON), high-fat (HF) and HF supplemented with fructooligosaccharide (32 g; HF-FOS) treatments for 12 weeks (n = 10/group). At sacrifice, left ventricles were either frozen or preserved in formalin. Serum was stored for glucose and insulin measurements. Protein spectra was obtained using an Orbitrap analyzer, processed with Sequest and fold changes assessed with Scaffold Q +. Treatment effects for body weights, glucose and insulin were assessed using one-way ANOVA, and the differential protein expression was assessed by a Mann-Whitney U test. The Database for Annotation, Visualization and Integrated Discovery and the Kyoto Encyclopedia of Genes and Genomes identified pathways containing overrepresented proteins. Hematoxylin and eosin sections were graded for hypertrophy and also quantified; differences were identified using Chi-square analyses and Mann-Whitney U tests. HF diet fed rats were significantly (p < 0.05) heavier than CON, and 23 proteins involved in mitochondrial function and lipid metabolism were differentially expressed between HF and CON. Between HF-FOS and HF, 117 proteins involved in contractility, lipid and carbohydrate metabolism were differentially expressed. HF cardiomyocytes were significantly (p < 0.05) more hypertrophic than CON. We conclude that high-fat feeding and FOS are associated with subcellular deviations in cardiac metabolism and contractility, which may influence myocardial function and alter the risk of cardiovascular disease.

The effects of probiotic/synbiotic supplementation compared to placebo on biomarkers of oxidative stress in adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

During the last decades, there has been a burst of scientific literature hypothesizing the antioxidant effect of probiotics. However, the results of these studies are inconsistent and a final conclusion has yet to be reached. Thus, the aim of this study was to assess the effects of probiotic/synbiotic supplementation on serum total antioxidant capacity (TAC), glutathione (GSH), malondialdehyde (MDA) and nitric oxide (NO) levels in adults.

METHODS AND RESULTS

The following online databases were searched until August 26th 2020: PubMed/Medline, Scopus, Clarivate Analytics Web of Science, Cochrane Central Register of Controlled Trials, Science Direct, Google Scholar and Igaku Chuo Zasshi. The effect sizes were expressed as the weighted mean difference (WMD) with 95% confidence intervals (CI). A total of 31 eligible trials with 1681 participants (839 cases and 842 controls) were included in this meta-analysis. The results revealed that the supplementation with probiotics/synbiotics, significantly increased serum TAC (WMD: 54.14 mmol/L, 95% CI: 27.87, 80.40, P < 0.001), GSH (WMD: 40.38 μmol/L, 95% CI: 20.72, 60.03, P < 0.001) and NO (WMD: 3.54 μmol/L, 95% CI: 1.73, 5.34, P < 0.001) levels. In addition, MDA levels were significantly reduced (WMD: -0.45 μmol/L, 95% CI: -0.58,-0.32, P < 0.001) following probiotic/synbiotic supplementation. None of the variables showed a significant change in the sensitivity analysis.

CONCLUSION

Available evidence suggests that probiotic/synbiotic supplementation can significantly increase serum TAC, GSH and NO, as well as reduce MDA levels in adults. Therefore, probiotic/synbiotic supplementation may play a role in improving antioxidant indices and reducing oxidative stress in the body.

Microbiota and Diabetes Mellitus: Role of Lipid Mediators

Diabetes Mellitus (DM) is an inflammatory clinical entity with different mechanisms involved in its physiopathology. Among these, the dysfunction of the gut microbiota stands out. Currently, it is understood that lipid products derived from the gut microbiota are capable of interacting with cells from the immune system and have an immunomodulatory effect. In the presence of dysbiosis, the concentration of lipopolysaccharides (LPS) increases, favoring damage to the intestinal barrier. Furthermore, a pro-inflammatory environment prevails, and a state of insulin resistance and hyperglycemia is present. Conversely, during eubiosis, the production of short-chain fatty acids (SCFA) is fundamental for the maintenance of the integrity of the intestinal barrier as well as for immunogenic tolerance and appetite/satiety perception, leading to a protective effect. Additionally, it has been demonstrated that alterations or dysregulation of the gut microbiota can be reversed by modifying the eating habits of the patients or with the administration of prebiotics, probiotics, and symbiotics. Similarly, different studies have demonstrated that drugs like Metformin are capable of modifying the composition of the gut microbiota, promoting changes in the biosynthesis of LPS, and the metabolism of SCFA.

A P4 Medicine Perspective of Gut Microbiota and Prediabetes: Systems Analysis and Personalized Intervention

Type 2 diabetes (T2D) accounts for approximately 90% of diabetes worldwide and has become a global public health problem. Generally, individuals go to hospitals and get healthcare only when they have obvious T2D symptoms. While the underlying cause and mechanism of the disease are usually not well understood, treatment is for the symptoms, but not for the disease cause, and patients often continue to progress with more symptoms. Prediabetes is the early stage of diabetes and provides a good time window for intervention and prevention. However, with few symptoms, prediabetes is usually ignored without any treatment. Obviously, it is far from ideal to rely on the traditional medical system for diabetes healthcare. As a result, the medical system must be transformed from a reactive approach to a proactive approach. Root cause analysis and personalized intervention should be conducted for patients with prediabetes. Based on systems medicine, also known as P4 medicine, with a predictive, preventive, personalized, and participatory approach, new medical system is expected to significantly promote the prevention and treatment of chronic diseases such as prediabetes and diabetes. Many studies have shown that the occurrence and development of diabetes is closely related to gut microbiota. However, the relationship between diabetes and gut microbiota has not been fully elucidated. This review describes the research on the relationship between gut microbiota and diabetes and some exploratory trials on the interventions of prediabetes based on P4 medicine model. Furthermore, we also discussed how these findings might influence the diagnosis, prevention and treatment of diabetes in the future, thereby to improve the wellness of human beings.

Dietary fiber and its associations with depression and inflammation

Dietary fiber is a crucial component of a healthy diet, with benefits that can be attributed to processes in the gut microbiota and the resulting by-products. Observational studies support associations between dietary fiber intake and depression and inflammation, but the potential mechanisms are poorly understood. This review examines evidence of the effects of dietary fiber on depression and inflammation and considers plausible mechanisms linking dietary fiber and depression, including microbiota-driven modification of gene expression and increased production of neurotransmitters. Additionally, inflammation may mediate the relationship between dietary fiber intake and depression. A high-fiber diet potentially lowers inflammation by modifying both the pH and the permeability of the gut. The resultant reduction in inflammatory compounds may alter neurotransmitter concentrations to reduce symptoms of depression. Further research into the link between dietary fiber intake and inflammation and depression is essential, as findings could potentially provide guidance for improvement in or prevention of inflammatory and depressive disorders.

From the gut to the heart: L. plantarum and inulin administration as a novel approach to control cardiac apoptosis via 5-HT2B and TrkB receptors in diabetes

BACKGROUND & AIMS

Type 2 diabetes mellitus, as a metabolic disorder, can lead to diabetic cardiomyopathy, identified by cardiomyocyte apoptosis and myocardial fibrosis. Brain-derived neurotrophic factor (BDNF) and serotonin are two neurotransmitters that can control cardiomyocyte apoptosis and myocardial fibrosis through their cardiac receptors. In the present study, we investigated the impacts of L. plantarum and inulin supplementation on the inhibition of cardiac apoptosis and fibrosis by modulating intestinal, serum, and cardiac levels of serotonin and BDNF as well as their cardiac receptors.

METHODS

Diabetes was induced by a high-fat diet and streptozotocin in male Wistar rats. Rats were divided into six groups and were supplemented with L. plantarum, inulin or their combination for 8 weeks. Finally, the rats were killed and levels of intestinal, serum, and cardiac parameters were evaluated.

RESULTS

Concurrent administration of L. plantarum and inulin caused a significant rise in the expression of cardiac serotonin and BDNF receptors (P < 0.001) as well as a significant fall in cardiac interstitial and perivascular fibrosis (P < 0.001, both) and apoptosis (P = 0.01). Moreover, there was a strong correlation of cardiac 5-Hydroxytryptamine 2B (5-HT2B) and tropomyosin receptor kinase B (TrkB) receptors with interstitial/perivascular fibrosis and apoptosis (P < 0.001, both).

CONCLUSIONS/INTERPRETATION

Results revealed beneficial effects of L. plantarum, inulin or their combination on intestinal, serum, and cardiac serotonin and BDNF accompanied by higher expression of their cardiac receptors and lower levels of cardiac apoptotic and fibrotic markers. It seems that L. plantarum and inulin supplementation could be considered as a novel adjunct therapy to reduce cardiac complications of type 2 diabetes mellitus.

Inulin-type fructan intervention restricts the increase in gut microbiome-generated indole in patients with peritoneal dialysis: a randomized crossover study

BACKGROUND

Indoxyl sulfate (IS) and p-cresyl sulfate (pCS), 2 important protein-bound uremic toxins, are independent risk factors for cardiovascular disease in patients with end-stage renal disease. Indole and p-cresol are gut microbiome-generated precursors of IS and pCS.

OBJECTIVE

The aim of the present study was to determine whether inulin-type fructans (ITFs) reduce the production of indole and p-cresol by altering their producing bacteria in patients with peritoneal dialysis.

METHODS

Patients receiving peritoneal dialysis for >3 mo without diabetes and not using antibiotics were recruited to a randomized, double-blind, placebo-controlled, crossover trial of ITF intervention over 36 wk (12-wk washout). The primary outcomes were gut microbiome, fecal indole and p-cresol, indole-producing bacteria, p-cresol-producing bacteria, and serum IS and pCS. The secondary outcomes were fecal pH, 24-h urine, and dialysis removal of IS and pCS.

RESULTS

Of 21 individuals randomly assigned, 15 completed the study. The daily nutrient intakes, including protein, tryptophan, and tyrosine, were isostatic during the prebiotic, washout, and placebo intervention. There were no baseline differences in the outcomes of interest between treatments. For fecal indole, its concentrations did not change significantly in either treatment. However, there was a trend toward the treatment-by-time effect (P = 0.052), with a quantitative reduction in the ITF treatment and an increase in the control. The difference in the changes between the 2 treatments was significant (-10.07 ± 7.48 μg/g vs +13.35 ± 7.66 μg/g; P = 0.040). Similar to Bacteroides thetaiotaomicron, there was a difference over time between the 2 treatments, with a significant treatment and time interaction effect (P = 0.047). There were no treatment, time, or interaction effects for fecal p-cresol, serum IS and pCS, 24-h urine, and dialysis removal of IS and pCS.

CONCLUSIONS

Our results suggested that ITFs restricted the increase in gut microbiome-generated indole in patients with peritoneal dialysis. This trial was registered at http://www.chictr.org.cn/showproj.aspx?proj=21228 as ChiCTR-INR-17013739.

Nutrition and the Immune System: A Complicated Tango

Enthusiasm exists for the potential of diet to impact the immune system, prevent disease and its therapeutic potential. Herein, we describe the challenge to nutrition scientists in defining this relationship through case studies of diets and nutrients in the context of allergic and autoimmune diseases. Moderate-quality evidence exists from both human intervention and observational studies to suggest that diet and individual nutrients can influence systemic markers of immune function and inflammation; numerous challenges exist for demonstrating the impact of defined diets and nutrient interventions on clearly influencing immune-mediated-clinical disease endpoints. A growing body of evidence suggests that further consideration of dietary patterns, immune system and gut microbiome composition and function, and subsequent epigenetic modifications are needed to improve our understanding of diet-immune system interactions.

Prebiotic supplementation modulates advanced glycation end-products (AGEs), soluble receptor for AGEs (sRAGE), and cardiometabolic risk factors through improving metabolic endotoxemia: a randomized-controlled clinical trial

PURPOSE

The oxidative stress plays a key role in the initiation, propagation, and development of the complications of type 2 diabetes mellitus (T2DM). This trial aimed to evaluate the effects of resistant dextrin as a prebiotic on the cardiometabolic risk factors and the status of oxidative stress in patients with T2DM.

METHODS

Sixty-five female subjects with T2DM were assigned to either the intervention (n = 33) or control (n = 32) groups receiving 10 g/day of resistant dextrin or placebo, respectively, for 8 weeks. Fasting blood samples were collected at baseline and post-intervention to determine the serum levels of glycemic indices, lipid profile, atherogenic indices, and soluble receptor for AGEs (sRAGE), carboxymethyl lysine (CML), pentosidine, malondialdehyde (MDA), 8-iso-prostaglandin F2α (8-iso-PGF2α), total antioxidant capacity (TAC), antioxidant enzymes activity, and uric acid. Data were analyzed using SPSS software 17. Paired, unpaired Student's t tests, and analysis of covariance were used to compare the quantitative variables.

RESULTS

Resistant dextrin caused a significant decrease in FPG (- 17.43 mg/dl, 9.80%), TG (- 40.25 mg/dl, 23.01%), TC/HDL (- 0.80, 21.87%), LDL-c/HDL-c (- 0.80, 17.85%), Atherogenic index (- 0.40, 15.80%), LPS (- 6.5 EU/ml, 23.40%) and hs-CRP (- 8.02 ng/ml, 54.00%), MDA (- 1.21 nmol/mL, 25.58%), CML (- 93.40 ng/ml, 26.30%), 8-iso-PGF2α (- 4.65 pg/ml, 15.00%), and a significant increase in TAC (0.33 mmol/L, 36.25%) and s-RAGE (2.10 ng/ml, 28.90%) in the intervention group compared with the control group. No significant changes were observed in glycosylated hemoglobin, total cholesterol, LDL-c, HDL-c, superoxide dismutase, glutathione peroxidase and catalase, pentosidine, and uric acid in the intervention group compared with the control group.

CONCLUSIONS

Supplementation with resistant dextrin may improve the advanced glycation end-products, sRAGE, and cardiometabolic risk factors in women with type 2 diabetes mellitus.

Formation of advanced glycation endproducts in foods during cooking process and underlying mechanisms: a comprehensive review of experimental studies

Advanced glycation endproducts (AGE) are a group of complex and heterogeneous molecules, sharing some common characteristics such as covalent cross-link formation among proteins, the effect of transforming the colour of food products into yellow-brown colours and fluorescence formation. AGE are linked to many diseases including diabetes, renal diseases, CVD, liver diseases, neuro-degenerative and eye disorders, female reproductive dysfunction, and even cancer. AGE are formed endogenously but are also provided from exogenous sources including diet and tobacco. Western diet, rich in processed and/or heat-treated foods, fat and sugar, increases the exposure to AGE. The foods that contain high levels of fat and protein are generally rich in terms of AGE, and are also prone to AGE formation during cooking compared with carbohydrate-rich foods such as vegetables, fruits, legumes and whole grains. The present article aimed to review the literature about the effects of different cooking methods and conditions on the AGE content of food and AGE formation mechanisms using a comprehensive approach.

Effects of resistant starch on glycemic control, serum lipoproteins and systemic inflammation in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled clinical trials

The aim of this systematic review and meta-analysis was to evaluate the effects of resistant starch (RS) on glycemic status, serum lipoproteins and inflammatory markers in patients with metabolic syndrome (MetS) and related disorders. Two independent authors systematically searched online database including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until 30 April 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. The heterogeneity among the included studies was assessed using Cochrane's Q test and I-square (I²) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. Nineteen trials were included in this meta-analysis. Administration of RS resulted in significant reduction in fasting plasma glucose (FPG) (14 studies) (WMD: -4.28; 95% CI: -7.01, -1.55), insulin (12 studies) (WMD: -1.95; 95% CI: -3.22, -0.68), and HbA1C (8 studies) (WMD: -0.60; 95% CI: -0.95, -0.24). When pooling data from 13 studies, a significant reduction in total cholesterol levels (WMD: -8.19; 95% CI: -15.38, -1.00) and LDL-cholesterol (WMD: -8.57; 95% CI: -13.48, -3.66) were found as well. Finally, RS administration was associated with a significant decrease in tumor necrosis factor alpha (TNF-α) (WMD: -2.02; 95% CI: -3.14, -0.90). This meta-analysis showed beneficial effects of RS on improving FPG, insulin, HbA1c, total cholesterol, LDL-cholesterol and TNF-α levels in patients with MetS and related disorders, but it did not affect HOMA-IR, triglycerides, HDL-cholesterol, CRP and IL-6 levels.

Consumption of Chlorogenic Acids through Coffee and Health Implications

Chlorogenic acids (CGA) are the main antioxidant compounds in the Western diet, due to their high concentrations in coffee associated with the high consumption of the beverage. Until about 10 years ago, like many other phenolic compounds, CGA were thought to be poorly absorbed in the human digestive system. Along the years, large amounts of information on the absorption and metabolism of these compounds have been unveiled, and today, it is known that, on average, about one third of the consumed CGA from coffee is absorbed in the human gastrointestinal tract, although large inter-individual variation exists. Considering results from in vitro animal and human studies, it is possible to conclude that the antioxidant and anti-inflammatory effects of coffee CGA are responsible for, at least to a certain extent, the association between coffee consumption and lower incidence of various degenerative and non-degenerative diseases, in addition to higher longevity.

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).

A mix of dietary fermentable fibers improves lipids handling by the liver of overfed minipigs

Obesity induced by overfeeding ultimately can lead to nonalcoholic fatty liver disease, whereas dietary fiber consumption is known to have a beneficial effect. We aimed to determine if a supplementation of a mix of fibers (inulin, resistant starch and pectin) could limit or alleviate overfeeding-induced metabolic perturbations. Twenty female minipigs were fed with a control diet (C) or an enriched fat/sucrose diet supplemented (O + F) or not (O) with fibers. Between 0 and 56 days of overfeeding, insulin (+88%), HOMA (+102%), cholesterol (+45%) and lactate (+63%) were increased, without any beneficial effect of fibers supplementation. However, fibers supplementation limited body weight gain (vs. O, -15% at D56) and the accumulation of hepatic lipids droplets induced by overfeeding. This could be explained by a decreased lipids transport potential (-50% FABP1 mRNA, O + F vs. O) inducing a down-regulation of regulatory elements of lipids metabolism / lipogenesis (-36% SREBP1c mRNA, O + F vs. O) but not to an increased oxidation (O + F not different from O and C for proteins and mRNA measured). Glucose metabolism was also differentially regulated by fibers supplementation, with an increased net hepatic release of glucose in the fasted state (diet × time effect, P<.05 at D56) that can be explained partially by a possible increased glycogen synthesis in the fed state (+82% GYS2 protein, O + F vs. O, P=.09). The direct role of short chain fatty acids on gluconeogenesis stimulation is questioned, with probably a short-term impact (D14) but no effect on a long-term (D56) basis.

Biological Activities of Lactose-Based Prebiotics and Symbiosis with Probiotics on Controlling Osteoporosis, Blood-Lipid and Glucose Levels

Lactose-based prebiotics are synthesized by enzymatic- or microbial- biotransformation of lactose and have unique functional values. In this comprehensive review article, the biochemical mechanisms of controlling osteoporosis, blood-lipid, and glucose levels by lactose-based prebiotics and symbiosis with probiotics are reported along with the results of clinical investigations. Interaction between lactose-based prebiotics and probiotics reduces osteoporosis by (a) transforming insoluble inorganic salts to soluble and increasing their absorption to gut wall; (b) maintaining and protecting mineral absorption surface in the intestine; (c) increasing the expression of calcium-binding proteins in the gut wall; (d) remodeling osteoclasts and osteoblasts formation; (e) releasing bone modulating factors; and (f) degrading mineral complexing phytic acid. Lactose-based prebiotics with probiotics control lipid level in the bloodstream and tissue by (a) suppressing the expressions of lipogenic- genes and enzymes; (b) oxidizing fatty acids in muscle, liver, and adipose tissue; (c) binding cholesterol with cell membrane of probiotics and subsequent assimilation by probiotics; (d) enzymatic-transformations of bile acids; and (e) converting cholesterol to coprostanol and its defecation. Symbiosis of lactose-based prebiotics with probiotics affect plasma glucose level by (a) increasing the synthesis of gut hormones plasma peptide-YY, glucagon-like peptide-1 and glucagon-like peptide-2 from entero-endocrine L-cells; (b) altering glucose assimilation and metabolism; (c) suppressing systematic inflammation; (d) reducing oxidative stress; and (e) producing amino acids. Clinical investigations show that lactose-based prebiotic galacto-oligosaccharide improves mineral absorption and reduces hyperlipidemia. Another lactose-based prebiotic, lactulose, improves mineral absorption, and reduces hyperlipidemia and hyperglycemia. It is expected that this review article will be of benefit to food technologists and medical practitioners.

Effects of Prebiotic and Synbiotic Supplementation on Glycaemia and Lipid Profile in Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials

Purpose: Diabetes Mellitus (T2DM) as a chronic disease, is on rise in parallel with other non-communicable diseases. Several studies have shown that probiotics and prebiotics might exert beneficial effects in chronic diseases including diabetes. Because of controversial results from different trials, the present study aims to assess the effects of prebiotic/synbiotic consumption on metabolic parameters in patients with type2 diabetes. Methods: A systematic literature search was performed on randomized controlled trial published in PubMed/Medline, SciVerse Scopus, Google scholar, SID and Magiran up to March 2018. Of a total number of 255 studies found in initial literature search, ten randomized controlled trials were included in the meta-analysis. The pooled mean net change were calculated in fasting blood-glucose [FBG], Hemoglobin A1c [HbA1c] and lipid markers (total cholesterol [TC], triglyceride [TG], low-density lipoprotein cholesterol [LDL-C], high density lipoprotein cholesterol [HDL-C]). The meta-analyses was conducted using Revman Software (v5.3). Results: The pooled estimate indicated a significant difference for the mean change in FBG, HbA1c and HDL in treatment group in comparison with control group. Subgroup analysis by intervention showed a significant difference in TG, LDL and HDL (synbiotic group) and in TG, TC, FBG, HDL and HbA1c (prebiotic group) compared with placebo. In another subgroup analysis, high quality studies showed significant reductions in TG, TC, FBG and HbA1c in intervention group compared with placebo group. Conclusion: In summary, diets supplemented with either prebiotics or synbiotics can result in improvements in lipid metabolism and glucose homeostasis in type 2 diabetic patients.

Targeting the gut microbiome to treat the osteoarthritis of obesity

Obesity is a risk factor for osteoarthritis (OA), the greatest cause of disability in the US. The impact of obesity on OA is driven by systemic inflammation, and increased systemic inflammation is now understood to be caused by gut microbiome dysbiosis. Oligofructose, a nondigestible prebiotic fiber, can restore a lean gut microbial community profile in the context of obesity, suggesting a potentially novel approach to treat the OA of obesity. Here, we report that - compared with the lean murine gut - obesity is associated with loss of beneficial Bifidobacteria, while key proinflammatory species gain in abundance. A downstream systemic inflammatory signature culminates with macrophage migration to the synovium and accelerated knee OA. Oligofructose supplementation restores the lean gut microbiome in obese mice, in part, by supporting key commensal microflora, particularly Bifidobacterium pseudolongum. This is associated with reduced inflammation in the colon, circulation, and knee and protection from OA. This observation of a gut microbiome-OA connection sets the stage for discovery of potentially new OA therapeutics involving strategic manipulation of specific microbial species inhabiting the intestinal space.

Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials

Background: There is strong epidemiologic evidence that dietary fiber intake is protective against overweight and obesity; however, results of intervention studies have been mixed. Soluble fiber beneficially affects metabolism, and fiber supplementation may be a feasible approach to improve body composition and glycemia in adults with overweight and obesity.Objective: We evaluated randomized controlled trials (RCTs) of isolated soluble fiber supplementation in overweight and obese adults on outcomes related to weight management [body mass index (BMI; in kg/m²), body weight, percentage of body fat, and waist circumference] and glucose and insulin metabolism (homeostasis model assessment of insulin resistance and fasting insulin) through a systematic review and meta-analysis.Design: We searched PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature and Cochrane Library databases. Eligible studies were RCTs that compared isolated soluble fiber with placebo treatments without energy-restriction protocols. Random-effects models were used to estimate pooled effect sizes and 95% CIs. Meta-regressions were performed to assess outcomes in relation to the intervention duration, fiber dose, and fiber type. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection.Results: Findings from 12 RCTs (n = 609 participants) from 2 to 17 wk of duration are summarized in this review. Soluble fiber supplementation reduced BMI by 0.84 (95% CI: -1.35, -0.32; P = 0.001), body weight by 2.52 kg (95% CI: -4.25, -0.79 kg; P = 0.004), body fat by 0.41% (95% CI: -0.58%, -0.24%; P < 0.001), fasting glucose by 0.17 mmol/L (95% CI: -0.28, -0.06 mmol/L; P = 0.002), and fasting insulin by 15.88 pmol/L (95% CI: -29.05, -2.71 pmol/L; P = 0.02) compared with the effects of placebo treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes.Conclusions: Isolated soluble fiber supplementation improves anthropometric and metabolic outcomes in overweight and obese adults, thereby indicating that supplementation may improve fiber intake and health in these individuals. However, the interpretation of these findings warrants caution because of the considerable between-study heterogeneity. This trial was registered at clinicaltrials.gov as NCT03003897.

Advanced glycation end products dietary restriction effects on bacterial gut microbiota in peritoneal dialysis patients; a randomized open label controlled trial

The modern Western diet is rich in advanced glycation end products (AGEs). We have previously shown an association between dietary AGEs and markers of inflammation and oxidative stress in a population of end stage renal disease (ESRD) patients undergoing peritoneal dialysis (PD). In the current pilot study we explored the effects of dietary AGEs on the gut bacterial microbiota composition in similar patients. AGEs play an important role in the development and progression of cardiovascular (CVD) disease. Plasma concentrations of different bacterial products have been shown to predict the risk of incident major adverse CVD events independently of traditional CVD risk factors, and experimental animal models indicates a possible role AGEs might have on the gut microbiota population. In this pilot randomized open label controlled trial, twenty PD patients habitually consuming a high AGE diet were recruited and randomized into either continuing the same diet (HAGE, n = 10) or a one-month dietary AGE restriction (LAGE, n = 10). Blood and stool samples were collected at baseline and after intervention. Variable regions V3-V4 of 16s rDNA were sequenced and taxa was identified on the phyla, genus, and species levels. Dietary AGE restriction resulted in a significant decrease in serum N^ε-(carboxymethyl) lysine (CML) and methylglyoxal-derivatives (MG). At baseline, our total cohort exhibited a lower relative abundance of Bacteroides and Alistipes genus and a higher abundance of Prevotella genus when compared to the published data of healthy population. Dietary AGE restriction altered the bacterial gut microbiota with a significant reduction in Prevotella copri and Bifidobacterium animalis relative abundance and increased Alistipes indistinctus, Clostridium citroniae, Clostridium hathewayi, and Ruminococcus gauvreauii relative abundance. We show in this pilot study significant microbiota differences in peritoneal dialysis patients’ population, as well as the effects of dietary AGEs on gut microbiota, which might play a role in the increased cardiovascular events in this population and warrants further studies.

Examining the gut bacteriome, virome, and mycobiome in glucose metabolism disorders: Are we on the right track?

Human gut microbiome is defined as the gene complement of the gut microbial community, measured via laboratory metagenomic techniques. It includes bacteriome, virome and mycobiome, which represent, respectively, the assemblages of bacteria, viruses and fungi, living in the human gut. Gut microbiota function as a living "organ" that interacts with the gastro-intestinal environment, provides nutrients and vitamins to the organism and transduces hormonal messages, essentially influencing the main metabolic pathways, including drug metabolism. A clear association between gut, and glucose metabolism disorders has recently emerged. Medications acting on glucose absorption in the gut, or enhancing gut hormone activity are already extensively employed in the therapy of diabetes. Moreover, the gut is characterized by immune, and autonomous neuronal features, which play a critical role in maintaining glucose metabolism homeostasis. Gut microbes respond to neuroendocrine, and immune biochemical messages, affecting the health, and behavior of the host. There is vast heterogeneity in the studies included in this review, hence a meta-analysis, or a systematic review were not applicable. In this article, we attempt to reveal the interplay between human gut microbiota physiology, and hyperglycemic states, synthesizing, and interpreting findings from human studies.

Chicory inulin ameliorates type 2 diabetes mellitus and suppresses JNK and MAPK pathways in vivo and in vitro

SCOPE

Chicory inulin is a naturally occurring fructan that is conducive to glucose and lipid metabolism in patients with diabetes mellitus. This study aims to investigate the mechanism by which chicory inulin improves glucolipid metabolism in diabetic conditions.

METHODS AND RESULTS

Rats were injected with streptozotocin and fed with high fat diet to induce diabetes, and then administrated with different doses of chicory inulin for 8 weeks. The glycometabolism and lipid metabolism parameters were determined, the activity of insulin receptor substrate (IRS) and mitogen-activated protein kinase (MAPK) pathways were examined by western blot. The effect of chicory inulin on glucose uptake of myoblast and hepatocyte were also measured in vitro. Data were analyzed by student's t-test or one-way analysis of variance followed by the Bonferroni post-hoc testing. The results showed that chicory inulin improved glucolipid metabolism, and it activated IRS but suppressed the MAPK pathways in vivo and in vitro.

CONCLUSION

Our study demonstrates that chicory inulin, as a nutritional supplement, may be beneficial for the patients with type 2 diabetes mellitus, and the metabolism-modulatory effect seems to be related with the inhibition of JNK and P38 MAPK pathways.

The Role of Supplemental Complex Dietary Carbohydrates and Gut Microbiota in Promoting Cardiometabolic and Immunological Health in Obesity: Lessons from Healthy Non-Obese Individuals

Dietary supplementation with complex carbohydrates is known to alter the composition of gut microbiota, and optimal implementation of the use of these so called "prebiotics" could be of great potential in prevention and possibly treatment of obesity and associated cardiometabolic and inflammatory diseases via changes in the gut microbiota. An alternative to this "microbiocentric view" is the idea that health-promoting effects of certain complex carbohydrates reside in the host, and could secondarily affect the diversity and abundance of gut microbiota. To circumvent this potential interpretational problem, we aimed at providing an overview about whether and how dietary supplementation of different complex carbohydrates changes the gut microbiome in healthy non-obese individuals. We then reviewed whether the reported changes in gut bacterial members found to be established by complex carbohydrates would benefit or harm the cardiometabolic and immunological health of the host taking into account the alterations in the microbiome composition and abundance known to be associated with obesity and its associated disorders. By combining these research areas, we aimed to give a better insight into the potential of (foods containing) complex carbohydrates in the treatment and prevention of above-mentioned diseases. We conclude that supplemental complex carbohydrates that increase Bifidobacteria and Lactobacilli, without increasing the deleterious Bacteroides, are most likely promoting cardiometabolic and immunological health in obese subjects. Because certain complex carbohydrates also affect the host's immunity directly, it is likely that host-microbiome interactions in determination of health and disease characteristics are indeed bidirectional. Overall, this review article shows that whereas it is relatively clear in which direction supplemental fermentable carbohydrates can alter the gut microbiome, the relevance of these changes regarding health remains controversial. Future research should take into account the different causes of obesity and its adverse health conditions, which in turn have drastic effects on the microbiome balance.

Methylglyoxal in Metabolic Disorders: Facts, Myths, and Promises

Glucose and fructose metabolism originates the highly reactive byproduct methylglyoxal (MG), which is a strong precursor of advanced glycation end products (AGE). The MG has been implicated in classical diabetic complications such as retinopathy, nephropathy, and neuropathy, but has also been recently associated with cardiovascular diseases and central nervous system disorders such as cerebrovascular diseases and dementia. Recent studies even suggested its involvement in insulin resistance and beta-cell dysfunction, contributing to the early development of type 2 diabetes and creating a vicious circle between glycation and hyperglycemia. Despite several drugs and natural compounds have been identified in the last years in order to scavenge MG and inhibit AGE formation, we are still far from having an effective strategy to prevent MG-induced mechanisms. This review summarizes the endogenous and exogenous sources of MG, also addressing the current controversy about the importance of exogenous MG sources. The mechanisms by which MG changes cell behavior and its involvement in type 2 diabetes development and complications and the pathophysiological implication are also summarized. Particular emphasis will be given to pathophysiological relevance of studies using higher MG doses, which may have produced biased results. Finally, we also overview the current knowledge about detoxification strategies, including modulation of endogenous enzymatic systems and exogenous compounds able to inhibit MG effects on biological systems.