Increase in colonic PRopionate as a method of prEVENTing weight gain in adults aged 20–40 years (iPREVENT): a multi-centre, double-blind, randomised, parallel-group study to investigate the efficacy of inulin-propionate ester versus inulin (control) in the prevention of weight gain over 12 months

Introduction: Overweight and obesity affects over 70% of the UK population and is a major risk factor for the development of co-morbidities, including type 2 diabetes and cardiovascular disease. There now exists a considerable evidence base for the management of obesity. However, this is not the case for the prevention of obesity. Preventing weight gain in periods of life where there is an elevated risk of fat mass expansion could be beneficial to preventing associated diseases in later life. This protocol investigates the impact of novel food ingredient inulin propionate ester (IPE) in the prevention of weight gain. This trial aims to investigate the primary hypothesis that IPE has a superior effect on preventing body weight gain, compared with inulin, in young (<40 years old) adults over 12 months, whilst also investigating several complementary mechanisms that may explain the prevention of weight gain and improved long-term energy balance from consuming IPE. Methods: In this multi-centre, double-blind, randomised, parallel-group study, eligible participants will be randomly assigned to consume 10g IPE or 10g inulin (control) daily for 12 months. Study visits will be conducted at baseline, two-month, six-month and 12-month time points. The primary outcome is weight gain from baseline to 12 months. Secondary outcomes will examine changes in metabolic and cardiovascular health biomarkers, body composition and appetite. A mechanistic sub-group will explore causal mechanisms around energy balance, body composition, appetite regulation and the gut microbiota. Based on the power calculation, the sample size required is 270 participants or 135 per study group. Ethics and dissemination: The trial protocol and participant-facing documents have been reviewed and approved, by the London Hampstead Ethics Committee (REC Reference 19/LO/0095, 29th January 2019). Upon completion, the trial results will be published in peer-reviewed journals and presented at scientific conferences. Trial registration number: ISRCTN16299902, 1st March 2018

A natural mutation in Pisum sativum L. (pea) alters starch assembly and improves glucose homeostasis in humans

Elevated postprandial glucose (PPG) is a significant risk factor for non-communicable diseases globally. Currently, there is a limited understanding of how starch structures within a carbohydrate-rich food matrix interact with the gut luminal environment to control PPG. Here, we use pea seeds (Pisum sativum) and pea flour, derived from two near-identical pea genotypes (BC1/19RR and BC1/19rr) differing primarily in the type of starch accumulated, to explore the contribution of starch structure, food matrix and intestinal environment to PPG. Using stable isotope 13C-labelled pea seeds, coupled with synchronous gastric, duodenal and plasma sampling in vivo, we demonstrate that maintenance of cell structure and changes in starch morphology are closely related to lower glucose availability in the small intestine, resulting in acutely lower PPG and promotion of changes in the gut bacterial composition associated with long-term metabolic health improvements

A Doubly Fmoc-Protected Aspartic Acid Self-Assembles into Hydrogels Suitable for Bone Tissue Engineering

Hydrogels have been used as scaffolds for biomineralization in tissue engineering and regenerative medicine for the repair and treatment of many tissue types. In the present work, we studied an amino acid-based material that is attached to protecting groups and self-assembles into biocompatible and stable nanostructures that are suitable for tissue engineering applications. Specifically, the doubly protected aspartic residue (Asp) with fluorenyl methoxycarbonyl (Fmoc) protecting groups have been shown to lead to the formation of well-ordered fibrous structures. Many amino acids and small peptides which are modified with protecting groups display relatively fast self-assembly and exhibit remarkable physicochemical properties leading to three-dimensional (3D) networks, the trapping of solvent molecules, and forming hydrogels. In this study, the self-assembling fibrous structures are targeted toward calcium binding and act as nucleation points for the binding of the available phosphate groups. The cell viability, proliferation, and osteogenic differentiation of pre-osteoblastic cells cultured on the formed hydrogel under various conditions demonstrate that hydrogel formation in CaCl2 and CaCl2-Na2HPO4 solutions lead to calcium ion binding onto the hydrogels and enrichment with phosphate groups, respectively, rendering these mechanically stable hydrogels osteoinductive scaffolds for bone tissue engineering

Use of Boronic Acid Disk Tests To Detect Extended- Spectrum β-Lactamases in Clinical Isolates of KPC Carbapenemase-Possessing Enterobacteriaceae▿

We evaluated boronic acid (BA)-based methods for their ability to detect extended-spectrum β-lactamases (ESBLs) among clinical isolates of KPC-producing members of the Enterobacteriaceae family. A total of 155 isolates of Klebsiella pneumoniae (n = 141), Escherichia coli (n = 6), Enterobacter aerogenes (n = 6), and Klebsiella oxytoca (n = 2) genotypically confirmed to be KPC producers were analyzed. As many as 118 isolates harbored ESBLs (103 harbored SHV-type ESBLs, 13 harbored CTX-M-type ESBLs, and 2 harbored both SHV- and CTX-M-type ESBLs); the remaining 37 isolates were genotypically negative for ESBL production. The CLSI ESBL confirmatory test was positive for 79 of the 118 ESBL producers (sensitivity, 66.9%), while all 37 non-ESBL producers were negative (specificity, 100%). When a ≥5-mm increase in the zone diameter of either the cefotaxime (CTX)-clavulanate (CA) or the ceftazidime (CAZ)-CA disks containing BA compared with the zone diameter of the CTX or CAZ disks containing BA was considered to be a positive result for ESBL production, the method detected all 118 ESBL producers (sensitivity, 100%) and showed no false-positive results for non-ESBL producers (specificity, 100%). Double-disk synergy tests, in which disks of CTX, CAZ, aztreonam, or cefepime in combination with BA were placed at distances of 20, 25, and 30 mm (center to center) from a disk containing amoxicillin (amoxicilline)-clavulanate-BA, were able to detect 116 (98.3%), 101 (85.6%), and 28 (23.7%) of the ESBL-positive isolates, respectively; no false-positive results for non-ESBL-producing isolates were detected. Our results demonstrate that the modified CLSI ESBL confirmatory test with antibiotic disks containing BA is the most accurate phenotypic method for the detection of ESBLs in Enterobacteriaceae producing KPC carbapenemases

Evaluation of Boronic Acid Disk Tests for Differentiating KPC-Possessing Klebsiella pneumoniae Isolates in the Clinical Laboratory▿

The worldwide increase in the occurrence and dissemination of KPC β-lactamases among gram-negative pathogens makes critical the early detection of these enzymes. Boronic acid disk tests using different antibiotic substrates were evaluated for detection of KPC-possessing Klebsiella pneumoniae isolates. A total of 57 genotypically confirmed KPC-possessing K. pneumoniae isolates with varying carbapenem MICs were examined. To measure the specificity of the tests, 106 non-KPC-possessing isolates (89 K. pneumoniae and 17 Escherichia coli isolates) were randomly selected among those exhibiting reduced susceptibility to cefoxitin, expanded-spectrum cephalosporins, or carbapenems. As many as 56, 53, and 40 of the non-KPC-possessing isolates harbored extended-spectrum β-lactamases, metallo-β-lactamases, and plasmid-mediated AmpC β-lactamases, respectively. By use of CLSI methodology and disks containing imipenem, meropenem, or cefepime, either alone or in combination with 400 μg of boronic acid, all 57 KPC producers gave positive results (sensitivity, 100%) whereas all 106 non-KPC producers were negative (specificity, 100%). The meropenem duplicate disk with or without boronic acid demonstrated the largest differences in inhibition zone diameters between KPC producers and non-KPC producers. By use of disks containing ertapenem, all isolates were correctly differentiated except for five AmpC producers that gave false-positive results (sensitivity, 100%; specificity, 95.3%). These practical and simple boronic acid disk tests promise to be very helpful for the accurate differentiation of KPC-possessing K. pneumoniae isolates, even in regions where different broad-spectrum β-lactamases are widespread