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1.
The effect of arabinoxylooligosaccharides on upper gastroduodenal motility and hunger ratings in humans.
Scarpellini, E, Deloose, E, Vos, R, Francois, I, Delcour, JA, Broekaert, WF, Verbeke, K, Tack, J
Neurogastroenterology and motility. 2018;(7):e13306
Abstract
BACKGROUND AND AIMS Prebiotics such as Arabinoxylooligosaccharides (AXOS) are non-digestible, fermentable food ingredients stimulating growth/activity of colonic bacteria with enhanced carbohydrates fermentation (CF) in humans. The migrating motor complex (MMC) of the gastrointestinal tract has been recently identified as an important hunger signal, but no data are available yet on the role of acute CF on MMC activity and related hunger ratings. Thus, we aimed to study the effect of acute AXOS CF on MMC and hunger in humans. METHODS A total of 13 healthy volunteers were randomized in a single-blind crossover placebo-controlled study where 9.4 g of AXOS or 10 g of maltodextrin and 1 g of unlabelled lactose ureide (LU) were given 12 hours prior to the study and, in the next morning, together with a pancake containing 500 mg of 13 C-LU. In 10 hours after the meal, 13 CO2 and hydrogen excretion were determined every 15 minutes while hunger/appetite ratings every 2 minutes through a VAS questionnaire. Five hours after the meal, antroduodenal motility was measured using HRM. KEY RESULTS AXOS significantly increased CF (158 ± 81 vs 840 ± 464 H2 ppm*minute, placebo vs AXOS, P < .05) without affecting the orocecal transit time (OCTT). AXOS had no significant effect on the occurrence, origin, and duration of phase III and on the total number, origin, and duration of phases I and II. Hunger and appetite scores prior and after phase III were not affected by AXOS. CONCLUSIONS AXOS acutely increases colonic fermentation, but this neither affects OCTT, activity of the MMC, nor interdigestive hunger scores in man.
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2.
Association of prophylactic synbiotics with reduction in diarrhea and pneumonia in mechanically ventilated critically ill patients: A propensity score analysis.
Shimizu, K, Ogura, H, Kabata, D, Shintani, A, Tasaki, O, Ojima, M, Ikeda, M, Shimazu, T
Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy. 2018;(10):795-801
Abstract
INTRODUCTION The preventive association of synbiotics therapy has not been thoroughly clarified in mechanically ventilated patients. The purpose of this study was to evaluate whether synbiotics therapy has preventive association against septic complications in ventilated critically ill patients. METHODS Critically ill patients who were mechanically ventilated were included in this retrospective observational study. Patients who received synbiotics (Bifidobacterium breve, Lactobacillus casei, and galactooligosaccharides) within 3 days after admission (denoted as synbiotics group) were compared with patients who did not receive synbiotics. The incidences of enteritis, pneumonia, and bacteremia were evaluated as clinical outcome. Enteritis was defined as an acute onset of diarrhea consisting of continuous liquid watery stools for more than 12 h. The confounding factors include APACHE II on admission, gender, the cause of admission and antibiotics. RESULTS We included 179 patients in this study: 57 patients received synbiotics and 122 patients did not receive synbiotics. The incidences of enteritis were significantly lower in the synbiotics group compared with the control group (3.5% vs. 15.6%; p < 0.05). The odds ratios for diarrhea-free days during the first 28 days for the synbiotics group as compared with the controls were 4.354 (95% confidence interval (CI), 2.407 to 7.877; p < 0.001) in an ordinal logistic regression model with propensity scores. The odds ratios for pneumonia-free days during the first 28 days for the synbiotics group were 2.529 (95% CI, 1.715 to 3.731; p < 0.001). The incidences of bacteremia did not have significant differences. CONCLUSION Prophylactic synbiotics appeared to have preventive association on enteritis and pneumonia in mechanically ventilated critically ill patients.
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3.
Dietary Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAPs) and Gastrointestinal Disease.
Vakil, N
Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition. 2018;(4):468-475
Abstract
FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Dietary modification of FODMAPs has been shown to have significant effects on the physiology of the gastrointestinal tract and improves symptoms of abdominal pain, distention, and bloating in patients with irritable bowel syndrome. Structured withdrawal and reintroduction of FODMAPs supervised by a dietitian is the optimal practice for dietary FODMAP modification in irritable bowel syndrome. FODMAPs are present in enteral feeding formulas and may have a role in diarrhea and bloating in tube-fed patients. Emerging areas of research include the effects of dietary modification of FODMAPs on the microbiome, micronutrient absorption, and caloric intake. FODMAP dietary modification is an emerging area in other gastrointestinal disorders and is of relevance to all practicing dietitians.
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4.
Human Milk Oligosaccharides as Promising Antivirals.
Morozov, V, Hansman, G, Hanisch, FG, Schroten, H, Kunz, C
Molecular nutrition & food research. 2018;(6):e1700679
Abstract
Human milk oligosaccharides (HMOs) are diverse unconjugated carbohydrates that are highly abundant in human breast milk. These glycans are investigated in the context of exhibiting multiple functions in infant growth and development. They seem to provide protection against infectious diseases, including a number of poorly manageable viral infections. Although the potential mechanism of the HMO antiviral protection is rather broad, much of the current experimental work has focused on studying of HMO antiadhesive properties. HMOs may mimic structures of viral receptors and block adherence to target cells, thus preventing infection. Still, the potential of HMOs as a source for new antiviral drugs is relatively unexploited. This can be partly attributed to the extreme complexity of the virus-carbohydrate interactions and technical difficulties in HMO isolation, characterization, and manufacturing procedures. Fortunately, we are currently entering a period of major technological advances that have enabled deeper insights into carbohydrate mediated viral entry, rational selection of HMOs as anti-entry inhibitors, and even evaluation of individual synthetic HMO structures. Here, we provide an up-to-date review on glycan binding studies for rotaviruses, noroviruses, influenza viruses, and human immunodeficiency viruses. We also discuss the preventive and therapeutic potential of HMOs as anti-entry inhibitors and address challenges on the route from fundamental studies to clinical trials.
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5.
Physiological effects of prebiotics and its role in prevention of necrotizing enterocolitis in preterm neonates.
Garg, BD, Balasubramanian, H, Kabra, NS
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2018;(15):2071-2078
Abstract
Necrotizing enterocolitis (NEC) is one of the most serious gastrointestinal emergencies in very low birth weight (VLBW) preterm neonates, affecting 7-14% of these neonates. Due to the seriousness of the disease, prevention of NEC is the most important goal. Current evidence from systematic review and meta-analysis revealed that probiotics are the most promising intervention in reduction of the incidence of NEC in VLBW neonates. As per the evidence, prebiotics modulate the composition of human intestine microflora to the benefit of the host by suppression of colonization of harmful microorganism and/or the stimulation of bifidobacterial growth, decreased stool viscosity, reduced gastrointestinal transit time, and better feed tolerance. Prebiotics may be potential alternatives or adjunctive therapies to probiotics, despite a lack of evidence supporting its clinical efficacy in prevention of NEC. In this article, we discuss evidence-based physiological effects of prebiotics and its therapeutic role in prevention of NEC.
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6.
Fructooligosaccharides and appetite.
Korczak, R, Slavin, JL
Current opinion in clinical nutrition and metabolic care. 2018;(5):377-380
Abstract
PURPOSE OF REVIEW Dietary fiber may play a role in obesity prevention through reduction of body weight and control of appetite, however, not all fibers are created equally, and characteristics of fiber such as viscosity, fermentability and solubility may affect appetite differently. RECENT FINDINGS Although early studies supported that fructan fibers, including inulin, fructooligosaccharides, and oligofructose affected satiety, more recent studies are less supportive. We found that a higher dose of fiber such as oligofructose (16 g/day) is needed and for a longer duration (12-16 weeks) to detect differences in appetite and subsequent energy intake, whereas, practical amounts of fructooligosaccharides, less than 10 g/day, generally do not affect satiety or food intake. It should be noted that there are many sources of fructan fibers, both in native foods, chicory roots, agave, and Jerusalem artichokes and isolated forms that vary in chain length. SUMMARY Fructan fibers, which include fructooligosaccharides, oligofructose, and inulin, provided in low doses (<10 g/day), generally do not affect measures of human appetite including satiety or food intake and should not be recommended as a fiber with sole satiating power.
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7.
Comparison of the thermal stabilization of proteins by oligosaccharides and monosaccharide mixtures: Measurement and analysis in the context of excluded volume theory.
Beg, I, Minton, AP, Islam, A, Hassan, MI, Ahmad, F
Biophysical chemistry. 2018;:31-37
Abstract
The thermal stability of apo α-lactalbumin (α-LA) and lysozyme was measured in the presence of mixtures of glucose, fructose, and galactose. Mixtures of these monosaccharides in the appropriate stoichiometric ratio were found to have a greater stabilizing effect on each of the two proteins than equal weight/volume concentrations of di- tri- and tetrasaccharides with identical subunit composition (sucrose, trehalose, raffinose, and stachyose). The excluded volume model for the effect of a single saccharide on the stability of a protein previously proposed by Beg et al. [Biochemistry 54 (2015) 3594] was extended to treat the case of saccharide mixtures. The extended model predicts quantitatively the stabilizing effect of all monosaccharide mixtures on α-LA and lysozyme reported here, as well as previously published results obtained for ribonuclease A [Biophys. Chem. 138 (2008) 120] to within experimental uncertainty.
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8.
Strategy in manipulating transglycosylation activity of glycosyl hydrolase for oligosaccharide production.
Abdul Manas, NH, Md Illias, R, Mahadi, NM
Critical reviews in biotechnology. 2018;(2):272-293
Abstract
BACKGROUND The increasing market demand for oligosaccharides has intensified the need for efficient biocatalysts. Glycosyl hydrolases (GHs) are still gaining popularity as biocatalyst for oligosaccharides synthesis owing to its simple reaction and high selectivity. PURPOSE Over the years, research has advanced mainly directing to one goal; to reduce hydrolysis activity of GHs for increased transglycosylation activity in achieving high production of oligosaccharides. DESIGN AND METHODS This review concisely presents the strategies to increase transglycosylation activity of GHs for oligosaccharides synthesis, focusing on controlling the reaction equilibrium, and protein engineering. Various modifications of the subsites of GHs have been demonstrated to significantly modulate the hydrolysis and transglycosylation activity of the enzymes. The clear insight of the roles of each amino acid in these sites provides a platform for designing an enzyme that could synthesize a specific oligosaccharide product. CONCLUSIONS The key strategies presented here are important for future improvement of GHs as a biocatalyst for oligosaccharide synthesis.
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9.
Solvent Networks Tune Thermodynamics of Oligosaccharide Complex Formation in an Extended Protein Binding Site.
Kunstmann, S, Gohlke, U, Broeker, NK, Roske, Y, Heinemann, U, Santer, M, Barbirz, S
Journal of the American Chemical Society. 2018;(33):10447-10455
Abstract
The principles of protein-glycan binding are still not well understood on a molecular level. Attempts to link affinity and specificity of glycan recognition to structure suffer from the general lack of model systems for experimental studies and the difficulty to describe the influence of solvent. We have experimentally and computationally addressed energetic contributions of solvent in protein-glycan complex formation in the tailspike protein (TSP) of E. coli bacteriophage HK620. HK620TSP is a 230 kDa native trimer of right-handed, parallel beta-helices that provide extended, rigid binding sites for bacterial cell surface O-antigen polysaccharides. A set of high-affinity mutants bound hexa- or pentasaccharide O-antigen fragments with very similar affinities even though hexasaccharides introduce an additional glucose branch into an occluded protein surface cavity. Remarkably different thermodynamic binding signatures were found for different mutants; however, crystal structure analyses indicated that no major oligosaccharide or protein topology changes had occurred upon complex formation. This pointed to a solvent effect. Molecular dynamics simulations using a mobility-based approach revealed an extended network of solvent positions distributed over the entire oligosaccharide binding site. However, free energy calculations showed that a small water network inside the glucose-binding cavity had the most notable influence on the thermodynamic signature. The energy needed to displace water from the glucose binding pocket depended on the amino acid at the entrance, in agreement with the different amounts of enthalpy-entropy compensation found for introducing glucose into the pocket in the different mutants. Studies with small molecule drugs have shown before that a few active water molecules can control protein complex formation. HK620TSP oligosaccharide binding shows that similar fundamental principles also apply for glycans, where a small number of water molecules can dominate the thermodynamic signature in an extended binding site.
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10.
Increasing Symptoms in Irritable Bowel Symptoms With Ingestion of Galacto-Oligosaccharides Are Mitigated by α-Galactosidase Treatment.
Tuck, CJ, Taylor, KM, Gibson, PR, Barrett, JS, Muir, JG
The American journal of gastroenterology. 2018;(1):124-134
Abstract
OBJECTIVES Galacto-oligosaccharides (GOS) are dietary FODMAPs (fermentable carbohydrates) associated with triggering gastrointestinal symptoms in patients with irritable bowel syndrome (IBS). This randomized, double-blind, placebo-controlled, cross-over trial aimed to assess whether oral α-galactosidase co-ingestion with foods high in GOS and low in other FODMAPs would reduce symptoms. METHODS Patients meeting the Rome III criteria for IBS who were hydrogen-producers on breath testing were recruited. Participants were treated with full-dose (300 GALU (galactosidic units) α-galactosidase) and half-dose enzyme (150 GALU α-galactosidase), and placebo (glucose) in a random order with ≤14 days washout between arms. Following a 3-day low FODMAP run-in period, participants consumed provided diets high in GOS for a further 3-days. Gastrointestinal symptoms were measured daily using a 100 mm visual-analogue-scale, and breath samples taken hourly on the second last day with hydrogen content analysed as area-under-the-curve. RESULTS Thirty-one patients with IBS (20 IBS-D, 4 IBS-C, 7 IBS-M) completed the study. The addition of high GOS foods resulted in a significant increase in overall symptoms with 21 patients exhibiting GOS-sensitivity (>10 mm increase for overall symptoms). Of those, full-dose enzyme reduced overall symptoms (median 24. 5(IQR 17.5-35.8) vs. 5.5(1.5-15.0) mm; P=0.006) and bloating (20.5(9.5-42.0) vs. 6.5(2.0-15.8); P=0.017). Breath hydrogen production was minimal with no differences seen between placebo and full-dose (P=0.597). CONCLUSIONS Oral α-galactosidase taken with high GOS foods provides a clinically significant reduction in symptoms in GOS-sensitive individuals with IBS. This strategy can be translated into practice to improve tolerance to high GOS foods as an adjunct therapy to the low FODMAP diet.