The impact of age, disease severity, and BMI on bone health and growth in children and young people with Crohn's disease.

Objectives: The objective of this study was to explore the correlation between paediatric Crohn's disease (CD) characteristics, bone health and growth parameters at diagnosis and follow-up. Methods: Retrospective data was collected for 47 children aged 4-16 who were newly diagnosed with CD between January 2018 and December 2019. Mean follow-up time was 2.5 years. Results: Eleven (24%) children had growth delay at diagnosis, which persisted in 4 (44%) of 9 recorded children at follow-up. Of the 35 children tested, 20 (57%) had inadequate Vitamin D levels (<50 mmol/L) at diagnosis. Thirty-seven (79%) children had a dual-energy X-ray absorptiometry scan at diagnosis, with 20 of them having at least 1 low Z-score. Children with poorer bone mineral density and bone mineral concentration Z-scores for age had a younger age at diagnosis (p = .042 and p = .021), more severe disease (p = .04 and p = .029) and a lower BMI (p < .001) at diagnosis. Children diagnosed with CD ≥11 years had a lower-than-expected height velocity (p < .0001 and p < .001). Multivariate regression analysis demonstrated an older age of diagnosis was a significant predictor of a lower height velocity at follow-up. Conclusion: Disease severity and age of diagnosis are important CD-related factors that influence bone health and growth. Vitamin D is an accessible component that if optimised can improve all three factors. Monitoring and optimising each aspect systematically has the potential to enable children to achieve their bone health and growth potentials.

Thromboprophylaxis Use in Paediatric Inflammatory Bowel Disease: An International RAND Appropriateness Panel.

BACKGROUND AND AIMS: Thromboprophylaxis use in paediatric inflammatory bowel disease [IBD] is inconsistent. Current guidelines only support treating children with acute severe colitis with risk factors. We convened an international RAND panel to explore thromboprophylaxis in paediatric IBD inpatients in the context of new evidence. METHODS: We convened a geographically diverse 14-person panel of paediatric gastroenterologists alongside supporting experts. An online survey was sent before an online meeting. Panellists were asked to rate the appropriateness of thromboprophylaxis in hospitalised paediatric IBD patients via 27 scenarios of varying ages, gender, and phenotype, with and without thrombotic risk factors. Anonymised results were presented at the meeting. A second modified survey was distributed to all panellists present at the meeting. Results from the second survey constitute the RAND panel results. The validated RAND disagreement index defined disagreement when ≥ 1. RESULTS: The combined outcome of thromboprophylaxis being considered appropriate until discharge and inappropriate to withhold was seen in 20 of 27 scenarios, including: all patients with new-onset acute severe colitis; all flares of known ulcerative colitis, irrespective of risk factors except in pre-pubescent patients with limited disease and no risk factors; and all Crohn's patients with risk factors. Disagreement was seen in five scenarios regarding Crohn's without risk factors, where outcomes were already uncertain. CONCLUSIONS: RAND panels are an established method to assess expert opinion in areas of limited evidence. This work therefore constitutes neither a guideline nor a consensus; however, the findings suggest a need to re-evaluate the role of thromboprophylaxis in future guidelines.

Advantages of Proactive Therapeutic Drug Monitoring in a Prospective Cohort of Children With Inflammatory Bowel Disease Treated With Anti-Tumour Necrosis Factor.

ABSTRACT: Few studies have addressed whether proactive therapeutic drug monitoring (TDM) results in improved clinical outcomes in children with inflammatory bowel disease (IBD) treated with anti-tumour necrosis factor. The aim of this study was to investigate the impact of using proactive TDM in this patient group.Pilot single-centre observational study to accrue data on patients managed with proactive TDM.More patients in the proactive TDM cohort were managed by escalating the infliximab (IFX) regime (P < 0.001). The need for switching to different biologics was significantly lower in this patient group (P < 0.001).The introduction of proactive TDM resulted in a significant reduction of patients requiring switch of their primary biologic. The results of this study are indicators that proactive TDM offers a better method of managing children with IBD on IFX therapy.

Controlling the Assembly of Coiled-Coil Peptide Nanotubes.

An ability to control the assembly of peptide nanotubes (PNTs) would provide biomaterials for applications in nanotechnology and synthetic biology. Recently, we presented a modular design for PNTs using α-helical barrels with tunable internal cavities as building blocks. These first-generation designs thicken beyond single PNTs. Herein we describe strategies for controlling this lateral association, and also for the longitudinal assembly. We show that PNT thickening is pH sensitive, and can be reversed under acidic conditions. Based on this, repulsive charge interactions are engineered into the building blocks leading to the assembly of single PNTs at neutral pH. The building blocks are modified further to produce covalently linked PNTs via native chemical ligation, rendering ca. 100 nm-long nanotubes. Finally, we show that small molecules can be sequestered within the interior lumens of single PNTs.

Modular Design of Self-Assembling Peptide-Based Nanotubes.

An ability to design peptide-based nanotubes (PNTs) rationally with defined and mutable internal channels would advance understanding of peptide self-assembly, and present new biomaterials for nanotechnology and medicine. PNTs have been made from Fmoc dipeptides, cyclic peptides, and lock-washer helical bundles. Here we show that blunt-ended α-helical barrels, that is, preassembled bundles of α-helices with central channels, can be used as building blocks for PNTs. This approach is general and systematic, and uses a set of de novo helical bundles as standards. One of these bundles, a hexameric α-helical barrel, assembles into highly ordered PNTs, for which we have determined a structure by combining cryo-transmission electron microscopy, X-ray fiber diffraction, and model building. The structure reveals that the overall symmetry of the peptide module plays a critical role in ripening and ordering of the supramolecular assembly. PNTs based on pentameric, hexameric, and heptameric α-helical barrels sequester hydrophobic dye within their lumens.