Outcomes of Tofacitinib Use in an Irish Pediatric Cohort

Background

Pediatric ulcerative colitis (UC) is typically more extensive and severe at diagnosis compared with adult disease. Tofacitinib, a Janus kinase inhibitor, has been used since 2018 to induce and maintain remission in UC. There are limited pediatric data regarding its use, either as a monotherapy or in combination with other treatments.

Objectives

To determine the real-world experience and outcomes of tofacitinib therapy in the Irish national cohort with pediatric UC.

Methods

A retrospective study of tofacitinib outcomes was undertaken at Ireland's single national center for pediatric inflammatory bowel disease. All patients commenced on tofacitinib since its availability in 2019 were included. Baseline and follow-up clinical characteristics, phenotype, Pediatric Ulcerative Colitis Activity Index (PUCAI) scores, and treatments before and after tofacitinib commenced were recorded. The primary outcome was remission by 8 weeks, with other clinical outcomes being recorded to maximal available follow-up.

Results

Between November 1, 2019 and June 30, 2022, 15 children (M:F 1:2) were prescribed tofacitinib, 5 as monotherapy. Thirteen had baseline pancolitis at diagnosis and all patients had prior infliximab exposure. The mean time from diagnosis to starting tofacitinib was 381 days (±SD 265). Dual therapy included 5 with infliximab, 4 with vedolizumab, and 1 with adalimumab. The average length of treatment on tofacitinib was 232 days (±SD 170) with 2 patients transitioning to adult services while in remission on tofacitinib therapy. The mean PUCAI score was 48.7 (±SD 14.1) pre-tofacitinib, 16.7 (±SD 15.6) at week 8, and 22.5 (±SD 29.6) by week 16, with a significant reduction in PUCAI by week 16 (P = 0.0004). Eight patients (3 monotherapy) achieved clinical remission, with 4 of the 5 dual therapy patients on infliximab. There were no significant outcome differences between those on mono- or dual therapy. Three patients with combined vedolizumab therapy did not achieve remission, 2 of whom required colectomy by week 24. There were no malignancies, 1 patient developed shingles and another developed herpangina post-tofacitinib. Failure to achieve clinical remission by week 16 was seen in all children who progressed to colectomy (n = 4).

Conclusion

Combining tofacitinib with other biologics is effective in select children with refractory UC. Early responders were more likely to achieve a sustained response at week 16. Failure to achieve remission by week 16 of tofacitinib therapy was strongly associated with progression to colectomy.

The oral microbiome in treatment naïve paediatric IBD patients exhibits dysbiosis related to disease severity that resolves following therapy

BACKGROUND

There is a limited literature describing the oral microbiome and its diagnostic potential in paediatric inflammatory bowel disease (IBD).

METHODS

We examined the dorsum tongue microbiome by V1-V2 sequencing in a cohort of 156 treatment naïve children diagnosed with IBD compared to 102 healthy control children. Microbiome changes over time following treatment were examined in a subset of patients and associations between IBD diagnosis and dysbiosis were explored.

RESULTS

Analysis of community structure of the microbiome in tongue samples revealed that IBD samples significantly diverged from healthy control samples (PERMANOVA P=0.0009) and exhibited a reduced abundance of Clostridia in addition to several major oral genera (Veillonella, Prevotella, Fusobacterium species) with an increased abundance of streptococci. This dysbiosis was more marked in patients with severe disease. Higher levels of the potential pathobionts Klebsiella and Pseudomonas spp. were also associated with IBD. In terms of predicted functions, the IBD oral microbiome was potentially more acidogenic and exhibited reduced capacity for B vitamin biosynthesis. We used a machine learning approach to develop a predictive model of IBD which exhibited a mean-prediction AUC: 0.762. Finally, we examined a subset of 53 patients following 12 months of therapy and could show resolution of oral dysbiosis demonstrated by a shift towards a healthy community structure and a significant reduction in oral dysbiosis.

CONCLUSION

Oral dysbiosis found in children with IBD is disease severity related and resolves over time following successful IBD treatment.

Mutations at the M2 and M3 Transmembrane Helices of the GABAARs α1 and β2 Subunits Affect Primarily Late Gating Transitions Including Opening/Closing and Desensitization

GABA type A receptors (GABA_ARs) belong to the pentameric ligand-gated ion channel (pLGIC) family and play a crucial role in mediating inhibition in the adult mammalian brain. Recently, a major progress in determining the static structure of GABA_ARs was achieved, although precise molecular scenarios underlying conformational transitions remain unclear. The ligand binding sites (LBSs) are located at the extracellular domain (ECD), very distant from the receptor gate at the channel pore. GABA_AR gating is complex, comprising three major categories of transitions: openings/closings, preactivation, and desensitization. Interestingly, mutations at, e.g., the ligand binding site affect not only binding but often also more than one gating category, suggesting that structural determinants for distinct conformational transitions are shared. Gielen and co-workers (2015) proposed that the GABA_AR desensitization gate is located at the second and third transmembrane segment. However, studies of our and others’ groups indicated that other parts of the GABA_AR macromolecule might be involved in this process. In the present study, we asked how selected point mutations (β₂G254V, α₁G258V, α₁L300V, and β₂L296V) at the M2 and M3 transmembrane segments affect gating transitions of the α₁β₂γ₂ GABA_AR. Using high resolution macroscopic and single-channel recordings and analysis, we report that these substitutions, besides affecting desensitization, also profoundly altered openings/closings, having some minor effect on preactivation and agonist binding. Thus, the M2 and M3 segments primarily control late gating transitions of the receptor (desensitization, opening/closing), providing a further support for the concept of diffuse gating mechanisms for conformational transitions of GABA_AR.

A typical Wegeners granulomatosis -- but not pauci-immune!

We present a the case of 58-year old man who was admitted to hospital with typical clinical features (bloody nasal discharge, arthralgia, acute kidney injury with a nephritic syndrome) consisting with Wegeners granulomatosis (WG). CT-scan showed pulmonary nodules and antineutrophil cytoplasmatic antibodies (ANCA) were elevated. A kidney biopsy showed a crescentic glomerulonephritis, but not pauci-immune-immune with a histopathological staining of a mesangioproliferative IgA-glomerulonephritis. The patient was put on prednisolone and i.v. cyclophosphamid (CYCLOPS-protocol (1). The anti-proteinase-3 antibody titer decreased and the CT-scan showed decreased activity of Wegener's granulomatosis (BVAS 26 dropped to 2) and the patient`s serum creatinine level was stable. The exact nosological relation of mesangial IgA-nephropathy to WG is still unclear. This case underlines that knowledge of renal histology is essential in the management of patients with renal disease, especially in patients with hematuria and/or proeinuria with positive ANCA.

Candidosis of the pharyngeal mucosa in patients with infectious mononucleosis

The aim of our study was to assess the frequency rate of Candida yeast-like fungi in isolations from nasal and pharyngeal mucosa in patients diagnosed with IM who had undergone an antibiotic therapy. The study was performed in 51 patients aged 17-33. The diagnosis of IM was made on the basis of clinical symptoms, haematological, biochemical and serologic examination results. The material constituted of nasal and pharyngeal swabs. The identification of Candida species was done according to the routine microbiological diagnostics. Our results show that among the Candida genus, C. albicans was the only pathogenic species isolated from patients with IM. It was observed only in pharyngeal swabs in 27.4% of the patients.

marvin: A Platform for Chemoinformatics Software Development

A strategy for a new type of platform for chemoinformatics software development and its first implementation are presented. The basic task of such a platform is to apply sequences of computational methods to high numbers of molecules. The implementation presented is based on four major components: (a) the application manager, responsible for running programs and for data management; (b) executable applications that supply limited pieces of functionality; (c) syntax definitions for data and control files and (d) the runtime library which comprises routines for data handling and user interface. This simple concept is implemented in the software package marvin. Different computational methods are available within marvin, including parts of commercial software packages (e.g. molecular modeling, bioinformatics, statistics, etc.) as well as newly developed and innovative algorithms. The basic layout of marvin is described and a simple example illustrates its application.

Action of calpastatin in prevention of cardiac L-type Ca2+ channel run-down cannot be mimicked by synthetic calpain inhibitors

Activity of L-type Ca2+ channels in a membrane patch disappears rapidly when the patch is excised from the cell into an artificial solution. This channel run-down observed in isolated membrane patches can however, be prevented by application of calpastatin, an endogenous protease inhibitor, and ATP. The high specificity of calpastatin for the protease calpain would clearly point to a participation of calpain activity in the run-down of Ca2+ channels. In an attempt to examine a possible involvement of calpain, three synthetic and rather specific calpain inhibitors were substituted for calpastatin. One of these inhibitors chosen for its membrane permeability in addition allowed calpain activity to be inhibited even before patch excision. The potency of these compounds in inhibiting calpain, specifically mu- and m-calpain, was first determined in a biochemical assay and then compared with their efficacy in preventing Ca2+ channel run-down. Surprisingly, calpastatin was least effective in calpain inhibition but by far the most potent in prevention of Ca2+ channel run-down. In addition run-down of Ca2+ channel activity was examined for its reversibility, which would not be expected upon involvement of a proteolytic process. However, Ca2+ channel activity clearly recovered after run-down by application of calpastatin. In contrast, synthetic calpain inhibitors were unable to reverse Ca2+ channel run-down. These results indicate that proteolysis might only be partially responsible for channel run-down and suggest an as yet unidentified function for calpastatin beyond its inhibitory action on calpain in the regulation of Ca2+ channel activity.