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Poor Sensitivity of Fecal Gluten Immunogenic Peptides and Serum Antibodies to Detect Duodenal Mucosal Damage in Celiac Disease Monitoring.
Laserna-Mendieta, EJ, Casanova, MJ, Arias, Á, Arias-González, L, Majano, P, Mate, LA, Gordillo-Vélez, CH, Jiménez, M, Angueira, T, Tébar-Romero, E, et al
Nutrients. 2020;(1)
Abstract
A lifelong gluten-free diet (GFD) is the only current treatment for celiac disease (CD), but strict compliance is complicated. Duodenal biopsies are the "gold standard" method for diagnosing CD, but they are not generally recommended for disease monitoring. We evaluated the sensitivity and specificity of fecal gluten immunogenic peptides (GIPs) to detect duodenal lesions in CD patients on a GFD and compared them with serum anti-tissue transglutaminase (tTG) IgA antibodies. A prospective study was conducted at two tertiary centers in Spain on a consecutive series of adolescents and adults with CD who maintained a long-lasting GFD. Adherence to a GFD and health-related quality of life were scored with validated questionnaires. Mucosal damage graded according to the Marsh-Oberhüber classification (Marsh 1/2/3) was used as the reference standard. Of the 97 patients included, 27 presented duodenal mucosal damage and 70 had normal biopsies (Marsh 0). The sensitivity (33%) and specificity (81%) of GIPs were similar to those provided by the two assays used to measure anti-tTG antibodies. Scores in questionnaires showed no association with GIP, but an association between GIPs and patients' self-reported gluten consumption was found (p = 0.003). GIP displayed low sensitivity but acceptable specificity for the detection of mucosal damage in CD.
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2.
Visceral Adiposity and Glucoregulatory Peptides are Associated with Susceptibility to Type 2 Diabetes: The TOFI_Asia Study.
Sequeira, IR, Yip, W, Lu, L, Jiang, Y, Murphy, R, Plank, L, Zhang, S, Liu, H, Chuang, CL, Vazhoor-Amarsingh, G, et al
Obesity (Silver Spring, Md.). 2020;(12):2368-2378
Abstract
OBJECTIVE Ethnic differences in fat deposition contribute to type 2 diabetes (T2D). Identification of biomarkers that underpin dysglycemia are needed for better-targeted prevention and treatment. METHODS The cross-sectional thin-on-the-outside-fat-on-the-inside (TOFI)_Asia study investigated adipose depots and clinical biomarkers as predictors of fasting plasma glucose (FPG) and insulin resistance (IR; assessed using the updated homeostatic model assessment of IR) in lean and overweight normo- and dysglycemic Chinese (n = 199) and Caucasian (n = 158) individuals. Multivariate least-angle regression models were used to identify predictors of FPG and IR. RESULTS At similar age and BMI, Chinese individuals had lower body weight but had a greater percentage of total abdominal adipose tissue and a greater percentage of total visceral adipose tissue (VAT) (all P < 0.005). In Chinese individuals, FPG, hemoglobin A1c , fasting insulin, and triglycerides were higher, whereas HDL cholesterol and total and high-molecular-weight adiponectin levels were lower (all P < 0.0001). Raised liver enzyme and peptide concentrations (P < 0.02) were consistent with increased T2D risk. Lean Chinese women (<25 kg/m2 ) had greater total abdominal adipose tissue (kilograms) and VAT (kilograms) than Caucasian women, exhibiting the TOFI profile, with raised FPG (P < 0.001) and IR (P = 0.01). Risk factors for elevated FPG specific to Chinese individuals included male gender, VAT, and triglycerides (R2 = 0.33), and risk factors for IR specific to Chinese individuals included amylin, C-peptide, and glucagon (R2 = 0.49). VAT, amylin, and C-peptide were predictors in Caucasian individuals. CONCLUSIONS VAT contributed to dysglycemia in both ethnicities, particularly in Chinese individuals characterized by the TOFI phenotype, as did the glucoregulatory peptides amylin and C-peptide, providing targets for T2D prevention.
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Glycaemic target attainment in people with Type 2 diabetes treated with insulin glargine/lixisenatide fixed-ratio combination: a post hoc analysis of the LixiLan-O and LixiLan-L trials.
Davidson, JA, Desouza, C, Fonseca, V, Frias, JP, Van Gaal, L, Giorgino, F, Chao, J, Dex, TA, Roberts, M, Saremi, A, et al
Diabetic medicine : a journal of the British Diabetic Association. 2020;(2):256-266
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Abstract
AIMS: Both fasting (FPG) and postprandial plasma glucose (PPG) contribute to HbA1c levels. We investigated the relationship between achievement of American Diabetes Association (ADA) and American Association of Clinical Endocrinologists (AACE) recommended FPG and/or PPG targets and glycaemic efficacy outcomes in two trials. METHODS In this post hoc analysis, data from participants with Type 2 diabetes in the phase 3 LixiLan-O (NCT02058147) and LixiLan-L (NCT02058160) trials were evaluated to compare the relationship between achievement of society-recommended FPG and/or PPG targets and efficacy (HbA1c change, HbA1c goal attainment, weight change) and safety outcomes in the treatment groups. RESULTS Across treatment arms, iGlarLixi achieved the highest proportion of participants meeting both ADA- and AACE-recommended FPG and PPG targets at study end in both trials. A higher proportion of participants in the iGlarLixi (fixed-ratio combination of insulin glargine and lixisenatide) vs. insulin glargine alone or lixisenatide alone treatment arms achieved HbA1c goals (P < 0.001 for overall comparisons), irrespective of ADA- or AACE-defined targets. Hypoglycaemia rates [any, documented symptomatic (plasma glucose ≤ 3.9 mmol/l), and clinically important (plasma glucose < 3.0 mmol/l)] were low across all groups. Participants treated with iGlarLixi tended to show weight loss or less weight gain compared with participants receiving insulin glargine alone. No differences were observed in average daily basal insulin dose at week 30 between the two treatment arms or across the different FPG and PPG target groups. CONCLUSION Insulin glargine and lixisenatide as a fixed-ratio combination resulted in more participants reaching both FPG and PPG targets, leading to better HbA1c target attainment.
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Whey protein but not collagen peptides stimulate acute and longer-term muscle protein synthesis with and without resistance exercise in healthy older women: a randomized controlled trial.
Oikawa, SY, Kamal, MJ, Webb, EK, McGlory, C, Baker, SK, Phillips, SM
The American journal of clinical nutrition. 2020;(3):708-718
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Abstract
BACKGROUND Aging appears to attenuate the response of skeletal muscle protein synthesis (MPS) to anabolic stimuli such as protein ingestion (and the ensuing hyperaminoacidemia) and resistance exercise (RE). OBJECTIVES The purpose of this study was to determine the effects of protein quality on feeding- and feeding plus RE-induced increases of acute and longer-term MPS after ingestion of whey protein (WP) and collagen protein (CP). METHODS In a double-blind parallel-group design, 22 healthy older women (mean ± SD age: 69 ± 3 y, n = 11/group) were randomly assigned to consume a 30-g supplement of either WP or CP twice daily for 6 d. Participants performed unilateral RE twice during the 6-d period to determine the acute (via [13C6]-phenylalanine infusion) and longer-term (ingestion of deuterated water) MPS responses, the primary outcome measures. RESULTS Acutely, WP increased MPS by a mean ± SD 0.017 ± 0.008%/h in the feeding-only leg (Rest) and 0.032 ± 0.012%/h in the feeding plus exercise leg (Exercise) (both P < 0.01), whereas CP increased MPS only in Exercise (0.012 ± 0.013%/h) (P < 0.01) and MPS was greater in WP than CP in both the Rest and Exercise legs (P = 0.02). Longer-term MPS increased by 0.063 ± 0.059%/d in Rest and 0.173 ± 0.104%/d in Exercise (P < 0.0001) with WP; however, MPS was not significantly elevated above baseline in Rest (0.011 ± 0.042%/d) or Exercise (0.020 ± 0.034%/d) with CP. Longer-term MPS was greater in WP than in CP in both Rest and Exercise (P < 0.001). CONCLUSIONS Supplementation with WP elicited greater increases in both acute and longer-term MPS than CP supplementation, which is suggestive that WP is a more effective supplement to support skeletal muscle retention in older women than CP.This trial was registered at clinicaltrials.gov as NCT03281434.
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The new place of enterohormones in intestinal failure.
Daoud, DC, Joly, F
Current opinion in clinical nutrition and metabolic care. 2020;(5):344-349
Abstract
PURPOSE OF REVIEW Since the approval of teduglutide, a glucagon-like peptide-2 (GLP-2) analog, for the treatment of patients with short bowel syndrome (SBS) associated with intestinal failure, enterohormone therapy has received significant interest and is becoming the first choice of treatment in selected patients. As such, it is paramount to assess and understand the new place of hormonal therapy in the algorithm of treatments in SBS-intestinal failure. RECENT FINDINGS Specialized intestinal failure units have recently reported their outcomes with teduglutide to evaluate if they are consistent with the phase III trials results. SBS-intestinal failure patients are very heterogenous including their response to this treatment, hence the importance of real-life studies beyond the context of clinical trials. Moreover, it is essential to find a consensus on criteria identifying candidate patients for teduglutide. In addition, the impact of teduglutide on quality of life and its cost-effectiveness are emerging as well as new enterohormone treatments are being studied whether it is long action GLP-2 analog or other ileocolonic break hormones like glucagon-like peptide-1 analog. SUMMARY Hormonotherapy is currently modifying the natural history of patients with SBS-intestinal failure by decreasing their need for parenteral support and possibly even complications associated with long-term parenteral support. Enterohormone treatment is now the cornerstone in SBS-intestinal failure and should be offered as a first-line therapy to selected patients.
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Evidence for Pentapeptide-Dependent and Independent CheB Methylesterases.
Velando, F, Gavira, JA, Rico-Jiménez, M, Matilla, MA, Krell, T
International journal of molecular sciences. 2020;(22)
Abstract
Many bacteria possess multiple chemosensory pathways that are composed of homologous signaling proteins. These pathways appear to be functionally insulated from each other, but little information is available on the corresponding molecular basis. We report here a novel mechanism that contributes to pathway insulation. We show that, of the four CheB paralogs of Pseudomonas aeruginosa PAO1, only CheB2 recognizes a pentapeptide at the C-terminal extension of the McpB (Aer2) chemoreceptor (KD = 93 µM). McpB is the sole chemoreceptor that stimulates the Che2 pathway, and CheB2 is the methylesterase of this pathway. Pectobacterium atrosepticum SCRI1043 has a single CheB, CheB_Pec, and 19 of its 36 chemoreceptors contain a C-terminal pentapeptide. The deletion of cheB_Pec abolished chemotaxis, but, surprisingly, none of the pentapeptides bound to CheB_Pec. To determine the corresponding structural basis, we solved the 3D structure of CheB_Pec. Its structure aligned well with that of the pentapeptide-dependent enzyme from Salmonella enterica. However, no electron density was observed in the CheB_Pec region corresponding to the pentapeptide-binding site in the Escherichia coli CheB. We hypothesize that this structural disorder is associated with the failure to bind pentapeptides. Combined data show that CheB methylesterases can be divided into pentapeptide-dependent and independent enzymes.
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Food protein-derived iron-chelating peptides: The binding mode and promotive effects of iron bioavailability.
Wu, W, Yang, Y, Sun, N, Bao, Z, Lin, S
Food research international (Ottawa, Ont.). 2020;:108976
Abstract
Iron is known as an essential nutrient in the human body. Insufficient iron uptake is easy to result in iron deficiency anemia, which is a public health problem in both developing and developed countries. Iron, complexed by iron-chelating peptides, have been proposed as a superior candidate to ionized iron for improving iron absorption and bioavailability. Nowadays, as more and more iron-chelating peptides are identified from different food sources, the iron-peptide binding mode attracts much attention. Meanwhile, many studies have been conducted on the iron-chelating peptides to make clear their iron bioavailability enhancement potential. The aim of this review is to provide an overview of research progress in food protein-derived iron-chelating peptides. The review would be of particular value for iron-peptide complexes as functional ingredients or iron supplements.
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Recent trends in peptide and protein-based hydrogels.
Katyal, P, Mahmoudinobar, F, Montclare, JK
Current opinion in structural biology. 2020;:97-105
Abstract
Hydrogels are classic examples of biomaterials that have found its niche in biomedical and allied fields. Here, we describe examples of peptide-based and protein-based hydrogels with a focus on smart gels that respond to various stimuli including temperature, pH, light, and ionic strength. With the recent advancements in computational modeling, it has been possible to predict as well as design peptide and protein sequences that can assemble into hydrogels with unique and improved properties. We briefly discuss coarse grained and atomistic simulations in designing peptides that can form hydrogels. In addition, we highlight the trends that will influence the future design and applications of hydrogels, with emphasis on bioadhesion, exosomes delivery, tissue and organoids engineering, and even intracellular production of gels.
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Use of Alcalase in the production of bioactive peptides: A review.
Tacias-Pascacio, VG, Morellon-Sterling, R, Siar, EH, Tavano, O, Berenguer-Murcia, Á, Fernandez-Lafuente, R
International journal of biological macromolecules. 2020;(Pt B):2143-2196
Abstract
This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.
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Late-Stage Diversification of Tryptophan-Derived Biomolecules.
Gruß, H, Sewald, N
Chemistry (Weinheim an der Bergstrasse, Germany). 2020;(24):5328-5340
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Abstract
Pd-mediated reactions have emerged as a powerful tool for the site-selective and bioorthogonal late-stage diversification of amino acids, peptides and related compounds. Indole moieties of tryptophan derivatives are susceptible to C2 H-activation, whereas halogenated aromatic amino acids such as halophenylalanines or halotryptophans provide a broad spectrum of different functionalisations. The compatibility of transition-metal-catalysed cross-couplings with functional groups in peptides, other biologically active compounds and even proteins has been demonstrated. This Review primarily compiles the application of different cross-coupling reactions to modify halotryptophans, halotryptophan containing peptides or halogenated, biologically active compounds derived from tryptophan. Modern approaches use regio- and stereoselective biocatalytic strategies to generate halotryptophans and derivatives on a preparative scale. The combination of bio- and chemocatalysis in cascade reactions is given by the biocompatibility and bioorthogonality of Pd-mediated reactions.