Prebiotic effects of wheat arabinoxylan related to the increase in bifidobacteria, Roseburia and Bacteroides/Prevotella in diet-induced obese mice

Background

Alterations in the composition of gut microbiota - known as dysbiosis - has been proposed to contribute to the development of obesity, thereby supporting the potential interest of nutrients targeting the gut with beneficial effect for host adiposity. We test the ability of a specific concentrate of water-extractable high molecular weight arabinoxylans (AX) from wheat to modulate both the gut microbiota and lipid metabolism in high-fat (HF) diet-induced obese mice.

Methodology/Principal Findings

Mice were fed either a control diet (CT) or a HF diet, or a HF diet supplemented with AX (10% w/w) during 4 weeks. AX supplementation restored the number of bacteria that were decreased upon HF feeding, i.e. Bacteroides-Prevotella spp. and Roseburia spp. Importantly, AX treatment markedly increased caecal bifidobacteria content, in particular Bifidobacterium animalis lactis. This effect was accompanied by improvement of gut barrier function and by a lower circulating inflammatory marker. Interestingly, rumenic acid (C18:2 c9,t11) was increased in white adipose tissue due to AX treatment, suggesting the influence of gut bacterial metabolism on host tissue. In parallel, AX treatment decreased adipocyte size and HF diet-induced expression of genes mediating differentiation, fatty acid uptake, fatty acid oxidation and inflammation, and decreased a key lipogenic enzyme activity in the subcutaneous adipose tissue. Furthermore, AX treatment significantly decreased HF-induced adiposity, body weight gain, serum and hepatic cholesterol accumulation and insulin resistance. Correlation analysis reveals that Roseburia spp. and Bacteroides/Prevotella levels inversely correlate with these host metabolic parameters.

Conclusions/Significance

Supplementation of a concentrate of water-extractable high molecular weight AX in the diet counteracted HF-induced gut dysbiosis together with an improvement of obesity and lipid-lowering effects. We postulate that hypocholesterolemic, anti-inflammatory and anti-obesity effects are related to changes in gut microbiota. These data support a role for wheat AX as interesting nutrients with prebiotic properties related to obesity prevention.

Arabinoxylan fibre improves metabolic control in people with Type II diabetes

OBJECTIVE

To determine whether diet supplementation with arabinoxylan-rich (AX)-fibre from wheat improves glycaemic control in Type II diabetes.

DESIGN

Randomized, crossover intervention trial.

SETTING

Monash Medical Centre.

SUBJECTS

A total of 15 subjects with Type II diabetes.

INTERVENTIONS

Over two 5-week periods, subjects supplemented their usual diet with control bread and muffins (50% whole wheat, 50% white flour) (control diet) or with AX-bread and muffins (50% whole wheat, 36% white flour, 14% AX fibre) (AX diet). Subjects completed a 7-day food diary. At 0 and 5 weeks, venous blood was collected for determination of fasting and 2 h glucose, insulin, fructosamine and blood lipids. Blood pressure, body weight and body fat were also determined. A 24 h faecal sample, from 12 subjects, was weighed and analysed for faecal polysaccharide as a marker for dietary compliance.

RESULTS

Control and AX diets were similar except the AX diet supplied an additional 15.1 (12.0-18.5) (mean (95% confidence intervals)) g/day dietary fibre (P=0.000). Consumption of the AX diet increased faecal output by 61.5 (0.2-122.8) g/day (P=0.05) on a wet weight basis and significantly lowered fasting and 2 h plasma glucose, 2 h insulin and serum fructosamine (P=0.002, 0.000, 0.015, and 0.02, respectively). Blood lipids, body weight, fat mass and blood pressure remained unchanged.

CONCLUSION

A supplement of 15 g/day of AX-rich fibre can significantly improve glycaemic control in people with Type II diabetes.

Xyloglucan, a Plant Polymer with Barrier Protective Properties over the Mucous Membranes: An Overview

Disruption of the epithelial barrier function has been recently associated with a variety of diseases, mainly at intestinal level, but also affecting the respiratory epithelium and other mucosal barriers. Non-pharmacological approaches such as xyloglucan, with demonstrated protective barrier properties, are proposed as new alternatives for the management of a wide range of diseases, for which mucosal disruption and, particularly, tight junction alterations, is a common characteristic. Xyloglucan, a natural polysaccharide derived from tamarind seeds, possesses a "mucin-like" molecular structure that confers mucoadhesive properties, allowing xyloglucan formulations to act as a barrier capable of reducing bacterial adherence and invasion and to preserve tight junctions and paracellular flux, as observed in different in vitro and in vivo studies. In clinical trials, xyloglucan has been seen to reduce symptoms of gastroenteritis in adults and children, nasal disorders and dry eye syndrome. Similar mucosal protectors containing reticulated proteins have also been useful for the treatment of irritable bowel syndrome and urinary tract infections. The role of xyloglucan in other disorders with mucosal disruption, such as dermatological or other infectious diseases, deserves further research. In conclusion, xyloglucan, endowed with film-forming protective barrier properties, is a safe non-pharmacological alternative for the management of different diseases, such as gastrointestinal and nasal disorders.

Ferulated Arabinoxylans and Their Gels: Functional Properties and Potential Application as Antioxidant and Anticancer Agent

In the last years, biomedical research has focused its efforts in the development of new oral delivery systems for the treatment of different diseases. Ferulated arabinoxylans are polysaccharides from cereals that have been gaining attention in the pharmaceutical field due to their prebiotic, antioxidant, and anticancer properties. The antioxidant and anticancer properties of these polysaccharides make them attractive compounds for the treatment of cancer, particularly colon cancer. In addition, ferulated arabinoxylans can form covalent gels through the cross-linking of their ferulic acids. Due to their particular characteristics, ferulated arabinoxylan gels represent an excellent alternative as colon-targeted drug delivery systems. The aim of the present work is to review the physicochemical and functional properties of ferulated arabinoxylans and their gels and to present the future perspectives for potential application as antioxidant and anticancer agents.

Arabinoxylan fibre consumption improved glucose metabolism, but did not affect serum adipokines in subjects with impaired glucose tolerance

The consumption of arabinoxylan, a soluble fibre fraction, has been shown to improve glycemic control in type 2 diabetic subjects. Soluble dietary fibre may modulate gastrointestinal or adipose tissue hormones regulating food intake. The present study investigated the effects of arabinoxylan consumption on serum glucose, insulin, lipids, leptin, adiponectin and resistin in subjects with impaired glucose tolerance. In a randomized, single-blind, controlled, crossover intervention trial, 11 adults consumed white bread rolls as either placebo or supplemented with 15 g arabinoxylan for 6 weeks with a 6-week washout period. Fasting serum glucose, insulin, triglycerides, unesterified fatty acids, apolipoprotein A1 and B, adiponectin, resistin and leptin were assessed before and after intervention. Fasting serum glucose, serum triglycerides and apolipoprotein A-1 were significantly lower during arabinoxylan consumption compared to placebo (p=0.029, p=0.047; p=0.029, respectively). No effects of arabinoxylan were observed for insulin, adiponectin, leptin and resistin as well as for apolipoprotein B, and unesterified fatty acids. In conclusion, the consumption of AX in subjects with impaired glucose tolerance improved fasting serum glucose, and triglycerides. However, this beneficial effect was not accompanied by changes in fasting adipokine concentrations.

Efficacy and safety of Gelsectan for diarrhoea-predominant irritable bowel syndrome: A randomised, crossover clinical trial

Background

Irritable bowel syndrome (IBS) is highly prevalent and presents a clinical challenge. Gelsectan is a medical device containing xyloglucan (XG), pea protein and tannins (PPT) from grape seed extract, and xylo-oligosaccharides (XOS), which act together to protect and reinforce the intestinal barrier.

Objective

The objective of this study is to evaluate the efficacy and safety of XG + PPT + XOS in patients with diarrhoea-predominant IBS (IBS-D).

Methods

In this double-blind study, 60 patients were randomly assigned to receive XG + PPT + XOS or placebo for 28 days, then crossed over to the alternative treatment. Patients were followed for 60 days.

Results

At Day 28, a significantly higher proportion of patients starting treatment with XG + PPT + XOS than placebo (87 vs 0%; p = 0.0019) presented normal stools (Bristol Stool Form Scale type 3-4). At Day 56, a significantly higher proportion of patients who crossed over to XG + PPT + XOS than placebo (93% vs 23%; p = 0.0001) presented normal stools. In the group allocated to receive XG + PPT + XOS after placebo, benefits of XG + PPT + XOS were maintained during follow-up. Subjective assessments of abdominal pain, bloating, quality of life and general health indicated significant improvement with XG + PPT + XOS over placebo. There were no related adverse events.

Conclusion

XG + PPT + XOS effectively controlled diarrhoea and alleviated clinical symptoms in patients with IBS-D, and was well tolerated.

Evidence-Based Review of BioBran/MGN-3 Arabinoxylan Compound as a Complementary Therapy for Conventional Cancer Treatment

INTRODUCTION

Conventional cancer treatment, including surgery, chemotherapy, and radiotherapy, may not be sufficient to eradicate all malignant cells and prevent recurrence. Intensive treatment often leads to a depressed immune system, drug resistance, and toxicity, hampering the treatment outcomes. BioBran/MGN-3 Arabinoxylan is a standardized arabinoxylan concentrate which has been proposed as a plant-based immunomodulator that can restore the tumor-induced disturbance of the natural immune system, including natural killer cell activity to fight cancer, complementing conventional therapies.

OBJECTIVES

To comprehensively review the available evidence on the effects and efficacies of MGN-3 as a complementary therapy for conventional cancer treatment.

METHODS

Systematic search of journal databases and gray literature for primary studies reporting the effects of MGN-3 on cancer and cancer treatment.

RESULTS

Thirty full-text articles and 2 conference abstracts were included in this review. MGN-3 has been shown to possess immunomodulating anticancer effects and can work synergistically with chemotherapeutic agents, in vitro. In murine models, MGN-3 has been shown to act against carcinogenic agents, and inhibit tumor growth, either by itself or in combination with other anticancer compounds. Fourteen successful MGN-3 treated clinical cases were found. Eleven clinical studies, including 5 nonrandomized, pre-post intervention studies and 6 randomized controlled trials (RCTs) were located. Reported effects include enhanced immunoprofile, reduced side effects, improved treatment outcomes; one RCT established significantly increased survival rates. There are no reports on adverse events on MGN-3. Most of the clinical trials are small studies with short duration.

CONCLUSION

There is sufficient evidence suggesting MGN-3 to be an effective immunomodulator that can complement conventional cancer treatment. However, more well-designed RCTs on MGN-3 are needed to strengthen the evidence base.

A placebo-controlled, double-blind, randomized controlled trial of a natural killer cell stimulant (BioBran MGN-3) in chronic fatigue syndrome

BACKGROUND

Previous research has suggested that natural killer (NK) cell activity may be reduced in patients with chronic fatigue syndrome (CFS).

AIM

To evaluate the effectiveness of a putative NK cell stimulant, BioBran MGN-3, in reducing fatigue in CFS patients.

DESIGN

Randomized, double-blind, placebo-controlled trial.

METHODS

We recruited 71 patients with CFS (according to the Centers for Disease Control 1994 criteria) attending an out-patient specialist CFS service. Participants were given oral BioBran MGN-3 for 8 weeks (2 g three times per day) or placebo equivalent. The primary outcome measure was the Chalder physical fatigue score. Self-reported fatigue measures, self-assessment of improvement, change in key symptoms, quality of life, anxiety and depression measures were also included.

RESULTS

Data were complete in 64/71 patients. Both groups showed marked improvement over the study duration, but without significant differences. Mean improvement in the Chalder fatigue score (physical scale) was 0.3 (95%CI -2.6 to 3.2) lower in the BioBran group.

DISCUSSION

The findings do not support a specific therapeutic effect for BioBran in CFS. The improvement showed by both groups over time highlights the importance of placebo controls when evaluating interventions in CFS.

Isolation of a gastroprotective arabinoxylan from sugarcane bagasse

After industrial processing, one-third of sugarcane culms is converted into residual bagasse. The xylan-rich hemicellulose components of the bagasse were extracted with hot aqueous alkali (AX-CRUDE). Approximately 82% of the extracted hemicelluloses was precipitated with ethanol (AX-PET). Both AX-CRUDE and AX-PET contained an arabinoxylan as confirmed by 13C NMR and methylation analysis. Fraction AX-PET was fed to female Wistar rats with ethanol-induced gastric lesions. Oral administrations of 30, 100, and 300 mg/kg reduced the gastric lesion area by over 50%, and replenished ethanol-induced depletion of glutathione. The polysaccharide also increased mucus production by over 70%, indicating its cytoprotective action on experimentally induced gastric ulcers. These findings are significant, since a biologically active compound can be extracted in high yields from an abundant, readily available residue.

Effects of a diet rich in arabinoxylan and resistant starch compared with a diet rich in refined carbohydrates on postprandial metabolism and features of the metabolic syndrome

PURPOSE

Low intake of dietary fibre is associated with the development of type 2 diabetes. Dyslipidaemia plays a key role in the pathogenesis of type 2 diabetes. Knowledge of the impact of dietary fibres on postprandial lipaemia is, however, sparse. This study aimed in subjects with metabolic syndrome to assess the impact on postprandial lipaemia and features of the metabolic syndrome of a healthy carbohydrate diet (HCD) rich in cereal fibre, arabinoxylan and resistant starch compared to a refined-carbohydrate western-style diet (WSD).

METHODS

Nineteen subjects completed the randomised, crossover study with HCD and WCD for 4-week. Postprandial metabolism was evaluated by a meal-challenge test and insulin sensitivity was assessed by HOMA-IR and Matsuda index. Furthermore, fasting cholesterols, serum-fructosamine, circulating inflammatory markers, ambulatory blood pressure and intrahepatic lipid content were measured.

RESULTS

We found no diet effects on postprandial lipaemia. However, there was a significant diet × statin interaction on total cholesterol (P = 0.02) and LDL cholesterol (P = 0.002). HCD decreased total cholesterol (-0.72 mmol/l, 95% CI (-1.29; -0.14) P = 0.03) and LDL cholesterol (-0.61 mmol/l, 95% CI (-0.86; -0.36) P = 0.002) compared with WSD in subjects on but not without statin treatment. We detected no other significant diet effects.

CONCLUSIONS

In subjects with metabolic syndrome on statins a 4-week diet rich in arabinoxylan and resistant starch improved fasting LDL and total cholesterol compared to subjects not being on statins. However, we observed no diet related impact on postprandial lipaemia or features of the metabolic syndrome. The dietary fibre x statin interaction deserves further elucidation.

Effect of a Product Containing Xyloglucan and Pea Protein on a Murine Model of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory disease of the skin, characterized by dryness and more or less severe itching. The etiology of AD is complex and has not been fully clarified, involving genetic susceptibility, immunological abnormalities, epidermal barrier dysfunction, and environmental factors. Xyloglucan (XG) and pea protein (PP) are two compounds of natural origin characterized by the ability to create a physical barrier that protects mucosae membranes, reducing inflammation. The aim of the present study was to evaluate the potential beneficial effects of XG + PP in both a mouse model of AD and Staphylococcus aureus (S. aureus) infection- associated AD. Mice were topically treated with 200 μL of 0.5% oxazolone on the dorsal skin three times a week for AD induction. Mice received XG and PP by topical administration 1 h before oxazolone treatment. In S. aureus infection-associated AD, to induce a superficial superinfection of the skin, mice were also treated with 5 μL of 10⁸ of a culture of S. aureus for 2 weeks; mice superinfected received XG and PP by topical administration 1 h before oxazolone + S. aureus. Four weeks later, the skin was removed for histological and biochemical analysis. Our results demonstrated the protective barrier effects of XG and PP characterized by a reduction in histological tissue changes, mastocyte degranulation, and tight junction permeability in the skin following oxazolone treatment. Moreover, XG + PP was able to preserve filaggrin expression, a hallmark of AD. Our data also support the effectiveness of XG + PP to reduce the damage by superinfection post AD induced by S. aureus. In conclusion, a future product containing XG and PP could be considered as a potentially interesting approach for the treatment of AD.

Inhibitory Effects of Acidic Xylooligosaccharide on Stress-induced Gastric Inflammation in Mice

The preventive effects of acidic xylooligosaccharide prepared from xylan of corncobs and related sugars on stress-induced gastric inflammation in mice were investigated. Oral administration of acidic xylooligosaccharide and hydrocortisone at doses of 100 and 200 mg/kg body weight significantly reduced the number of bleeding points in the gastric mucosa of mice loaded with cold-restraint stress. Acidic xylooligosaccharide showed concentration-dependent superoxide anion radical-scavenging activity at concentrations of 3.3-4.3 mg/mL and its IC50 was 3.5 mg/mL, although this value is approximately six times that of quercetin. The antioxidant activity of acidic xylooligosaccharide could contribute, in part, to its suppressive activities on stress-induced mouse gastritis. Xylose, xylobiose, xylan, and glucuronic acid showed no significant suppressive activities on mouse gastric inflammation at a dose of 100 mg/kg body weight. These results suggest that an appropriate degree of polymerization of xylan (larger than trimer) is necessary for the activities of acidic xylooligosaccharide.

Arabinoxylan rice bran (MGN-3/Biobran) enhances radiotherapy in animals bearing Ehrlich ascites carcinoma†

This study examines the ability of arabinoxylan rice bran (MGN-3/Biobran) to enhance the anti-cancer effects of fractionated X-ray irradiation of Ehrlich solid tumor-bearing mice. Swiss albino mice bearing tumors were exposed to the following: (i) Biobran treatment (40 mg/kg/day, intraperitoneal injections) beginning on day 11 post-tumor cell inoculation until day 30; (ii) ionizing radiation (Rad) 2 Gy at three consecutive doses on days 12, 14 and 16; or (iii) Biobran + Rad. Final tumor weight was suppressed by 46% for Biobran, 31% for Rad and 57% for the combined treatment (Biobran + Rad) relative to control untreated mice. Biobran and Rad also arrested the hypodiploid cells in the sub-G1-phase, signifying apoptosis by +102% and +85%, respectively, while the combined treatment induced apoptosis by +123%, with similar results in the degree of DNA fragmentation. Furthermore, Biobran + Rad upregulated the relative gene expression and protein level of p53 and Bax in tumor cells, down-regulated Bcl-2 expression, and increased the Bax/Bcl-2 ratio and caspase-3 activity, with the combined treatment greater than for either treatment alone. Additionally, the combined treatment modulated the decrease in body weight, the increase in liver and spleen weight, and the elevation of liver enzymes aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transferase to be within normal values. We conclude that Biobran enhances radiation therapy-induced tumor regression by potentiating apoptosis and minimizing toxicities related to radiation therapy, suggesting that Biobran may be useful in human cancer patients undergoing radiotherapy and warranting clinical trials.

Translational evaluation of Gelsectan® effects on gut barrier dysfunction and visceral pain in animal models and irritable bowel syndrome with diarrhoea

BACKGROUND

Gelsectan® is a formulation of xyloglucan (XG), pea protein, grape seed extract (PPGS) and xylo-oligosaccharides (XOS). Our aim was to examine the effect of Gelsectan® on rectal sensitivity in an animal model, abdominal pain in irritable bowel syndrome with diarrhoea (IBS-D) subjects and intestinal permeability in both conditions.

METHODS

Animals: Wistar rats received gavage with XOS, XG + PPGS or XG + PPGS + XOS, as a single dose or for 7 days before a partial restraint stress (PRS). Visceromotor response to rectal distension and total gut paracellular permeability to 51Cr-EDTA were assessed. Humans: IBS-D and control patients were involved. After initial colonoscopy with biopsy sampling Gelsectan® was administered to IBS-D patients for 12 weeks. Stool count and pain scores were documented. After treatment, colonoscopy was repeated. The permeability of biopsy samples was measured in Ussing-chambers. Adherent mucus layer, Muc-2 expression as well as TNFα, Interferon IFNγ were evaluated by histology/immunohistochemistry and ELISA assays, respectively.

RESULTS

Animal studies: In control rats, PRS significantly increased visceromotor response as well as gut paracellular permeability. Single dose administration of XG + PPGS + XOS failed to reverse PRS, but 7 days of oral treatment reversed PRS-induced rectal hypersensitivity and gut hyperpermeability. Human studies: Gelsectan® treatment significantly reduced and abdominal pain. Intestinal permeability in IBS-D patients was elevated compared with controls, Gelsectan® restored permeability in the ascendent colon. Periodic acid-Schiff-stained mucus layer was significantly thinner in IBS-D patients compared with controls, In both segments, mucus thickness and the proportion of Muc-2 positive cells were not affected by Gelsectan® treatment. IFNγ tissue level in the sigmoid colon shows modest mucosal inflammation in IBS-D.

CONCLUSIONS

Gelsectan® prevented rectal hypersensitivity in rats, abdominal pain in human and intestinal hyperpermeability in rat and human studies respectively. These effects involve restoration of gut permeability. Based on this translational study, Gelsectan® can be considered as an effective therapy for IBS-D symptoms.

[Effect of Hemoclar on lipid metabolism and the clinical picture of ischemic heart disease]

The article discusses the results of treatment of 38 patients suffering from ischemic heart disease with hemoclar given in a dose of 200 mg for 25-34 days. Ergometry was carried out and the values of lipid metabolism and creatine phosphokinase activity were studied before and after treatment. The drug caused noticeable decrease in the lipid level, mainly in types IIb and IV hyperlipoproteinemia. Medication with hemoclar was attended by a decrease in the frequency and strength of the anginal attacks and by a lesser increase in the activity of creatine phosphokinase during a load. No side-effects were recorded.