Precision Delivery of Human Bone Marrow-Derived Mesenchymal Stem Cells Into the Pancreas Via Intra-arterial Injection Prevents the Onset of Diabetes

Mesenchymal stem cells (MSCs) are a promising therapy to potentially treat diabetes given their potent anti-inflammatory and immune-modulatory properties. While these regenerative cells have shown considerable promise in cell culture, their clinical translation has been challenging. In part, this can be attributed to these cells not reaching the pancreas to exert their regenerative effects following conventional intravenous (IV) injection, with the majority of cells being trapped in the lungs in the pulmonary first-pass effect. In the present study, we will therefore examine whether direct delivery of MSCs to the pancreas via an intra-arterial (IA) injection can improve their therapeutic efficacy. Using a mouse model, in which repetitive low doses of STZ induced a gentle, but progressive, hyperglycemia, we tested bone marrow-derived MSCs (BM-MSCs) which we have shown are enriched with pro-angiogenic and immunomodulatory factors. In cell culture studies, BM-MSCs were shown to preserve islet viability and function following exposure to proinflammatory cytokines (IFN-γ, IL-1β, and TNF-α) through an increase in pAkt. When tested in our animal model, mice receiving IV BM-MSCs were not able to mitigate the effects of STZ, however those which received the same dose and batch of cells via IA injection were able to maintain basal and dynamic glycemic control, to similar levels as seen in healthy control animals, over 10 days. This study shows the importance of considering precision delivery approaches to ensure cell-based therapies reach their intended targets to enable them to exert their therapeutic effects.

Rates and Predictors of Long-term Clinical Outcomes in Patients With Perianal Crohn's Disease on Biologic Therapy

BACKGROUND AND GOALS

Perianal Crohn's disease (pCD) represents an aggressive phenotype with limited studies on long-term outcomes. We evaluated 5-year outcomes of these patients on biologic therapies.

METHODS

We performed a retrospective analysis of patients with pCD at a tertiary medical center. We used Kaplan-Meier curves to estimate rates and multivariate logistic regression to identify predictors of long-term outcomes.

RESULTS

We included 311 patients with pCD of which 168 patients were started on biologics [138 anti-tumor necrosis factor (TNF) α, 14 vedolizumab, 16 ustekinumab] at the time of diagnosis. Anti-TNF use at the time of diagnosis was associated with decreased rates of perianal abscess recurrence [hazard ratio (HR)=0.48, 95% confidence interval (CI): 0.32-0.74], whereas ustekinumab use was associated with increased rates of perianal fistula closure (HR=3.58, 95% CI: 1.04-12.35) and decreased rates of perianal abscess recurrence (HR=0.20, 95% CI: 0.07-0.56) at follow-up. Among patients who failed their first anti-TNF, switching to another anti-TNF was associated with decreased rates of colectomy (HR=0.20, 95% CI: 0.04-0.90) and permanent diversion (HR=0.16, 95% CI: 0.03-0.94) compared with ustekinumab, whereas vedolizumab use was associated with decreased perianal fistula closure (HR=0.22, 95% CI: 0.05-0.96) compared with ustekinumab. Predictors of colectomy included colonic disease (odds ratio=2.71, 95% CI: 1.36-5.38) and anal stenosis (odds ratio=4.44, 95% CI: 1.59-12.43).

CONCLUSION

Type of biologic use at the time of pCD diagnosis or after first anti-TNF failure may be associated with long-term outcomes in patients with pCD.

Precision Delivery of Steroids as a Rescue Therapy for Gastrointestinal Graft-versus-Host Disease in Pediatric Stem Cell Transplant Recipients

Graft versus host disease (GVHD) is one of the most serious complications following stem cell transplant in children and is a major cause of morbidity and mortality. Corticosteroids remain the mainstay of treatment, and although a majority of children respond to systemic steroids, those refractory to or dependent upon corticosteroids suffer from complications secondary to long-term steroid administration. This problem has prompted consideration of steroid-sparing treatment strategies, although the time to clinical remission can be variable. Intraarterial corticosteroid delivery has been used in adults as a rescue therapy in steroid-resistant patients, but its use in children has been limited. We investigated the feasibility of intraarterial steroid administration into the bowel and/or liver in a cohort of six pediatric patients with acute GVHD. All patients successfully underwent treatment with no serious adverse effects. Five of five (100%) patients with gastrointestinal bleeding due to GVHD had rapid symptom improvement by 48 h, which was durable up to three weeks. Three of four (75%) patients with hepatic GVHD had improved cholestasis following intraarterial steroid administration. Our experience with this small cohort preliminarily demonstrated the feasibility and safety of intraarterial steroid administration in children with acute GVHD. This approach warrants consideration as a rescue therapy in steroid-refractory cases and as a "bridge" therapy for children with severe acute GVHD who are transitioning to steroid-sparing regimens.

Case Series of Precision Delivery of Methylprednisolone in Pediatric Inflammatory Bowel Disease: Feasibility, Clinical Outcomes, and Identification of a Vasculitic Transcriptional Program

Systemic steroid exposure, while useful for the treatment of acute flares in inflammatory bowel disease (IBD), is associated with an array of side effects that are particularly significant in children. Technical advancements have enabled locoregional intraarterial steroid delivery directly into specific segments of the gastrointestinal tract, thereby maximizing tissue concentration while limiting systemic exposure. We investigated the feasibility of intraarterial steroid administration into the bowel in a cohort of nine pediatric patients who had IBD. This treatment approach provided symptom relief in all patients, with sustained relief (>2 weeks) in seven out of nine; no serious adverse effects occurred in any patient. In addition, we identified patterns of vascular morphologic changes indicative of a vasculopathy within the mesenteric circulation of inflamed segments of the bowel in pediatric patients with Crohn's disease, which correlated with disease activity. An analysis of publicly available transcriptomic studies identified vasculitis-associated molecular pathways activated in the endothelial cells of patients with active Crohn's disease, suggesting a possible shared transcriptional program between vasculitis and IBD. Intraarterial corticosteroid treatment is safe and has the potential to be widely accepted as a locoregional approach for therapy delivery directly into the bowel; however, this approach still warrants further consideration as a short-term "bridge" between therapy transitions for symptomatic IBD patients with refractory disease, as part of a broader steroid-minimizing treatment strategy.

Local Pentraxin-2 Deficit Is a Feature of Intestinal Fibrosis in Crohn's Disease

BACKGROUND

Pentraxin-2 (PTX-2) is a homo-pentameric plasma protein showing evidence of antifibrotic activity in Phase 2 clinical trials in idiopathic pulmonary fibrosis (IPF). Whether PTX-2 plays a role in other fibrotic diseases, including intestinal fibrosis which commonly occurs in inflammatory bowel disease (IBD), remains unknown.

AIMS

This study aimed to qualitatively and quantitatively assess PTX-2 expression in fibrostenotic Crohn's disease (FCD) and determine whether expression is correlated with postsurgical restenosis.

METHODS

Immunohistochemistry was performed in histologic sections of small bowel resected from patients with fibrostenotic Crohn's disease (FCD), comparing strictured segments with adjacent surgical margins from the same patient. Ileal resections from patients without inflammatory bowel disease were examined as controls.

RESULTS

PTX-2 signal was analyzed in 18 patients with FCD and 15 patients without IBD and localized predominantly to submucosal vasculature, including arterial subendothelium and internal elastic lamina, and perivascular connective tissue. PTX-2 signal in the surgical margins from patients with FCD strictures (where tissue architecture was normal) was consistently lower than non-IBD samples. Fibrostenotic regions showed increased PTX-2 signal relative to surgical margins from the same patient in 14/15 paired samples. Submucosal/mural PTX-2 signal in fibrostenotic tissue was lower in patients who subsequently experienced re-stenosis (P = 0.015).

CONCLUSIONS

This exploratory study is the first analysis of PTX-2 within the intestine, and demonstrates that PTX-2 signal is reduced in the architecturally normal bowel of patients with FCD. Lower submucosal PTX-2 levels in patients with re-stenosis raises the possibility of a protective role of PTX-2 in intestinal fibrosis.

Effects of CFTR modulators on serum biomarkers of liver fibrosis in children with cystic fibrosis

The cystic fibrosis (CF) transmembrane conductance regulator corrector/potentiator combinations lumacaftor/ivacaftor and elexacaftor/tezacaftor/ivacaftor improve sweat chloride, pulmonary function, and nutrition. Yet it is unclear whether they may also impact the progression of liver fibrosis, which is a substantial source of morbidity and mortality for patients with CF. We conducted a retrospective, single-center analysis of children and adolescents with CF treated with lumacaftor/ivacaftor and/or elexacaftor/tezacaftor/ivacaftor therapy, focusing on alterations in liver function tests and fibrosis indices using previously-established thresholds that corresponded with increased liver elastography. In pairwise comparisons of before and during treatment timepoints, we found that those with CF-associated liver involvement experienced significant decreases in gamma-glutamyl transferase, aspartate aminotransferase-to-platelet index, and gamma-glutamyl transferase-to-platelet ratio while on lumacaftor/ivacaftor. These differences were not observed in patients treated with elexacaftor/tezacaftor/ivacaftor, nor were they observed in patients without underlying CF-associated liver disease. These results provide the first evidence that lumacaftor/ivacaftor may improve liver fibrosis in children and adolescents with CF and suggest it may be beneficial in the treatment of CF-associated liver disease.

Warning Labels and High-Powered Magnet Exposures

BACKGROUND AND OBJECTIVES

High-powered magnets are among the most dangerous childhood foreign bodies. Consumer advocates and physicians have called for these products to be effectively banned, but manufacturers assert warning labels would sufficiently mitigate risk.

METHODS

Subjects from Injuries, Morbidity, and Parental Attitudes Concerning Tiny High-powered Magnets (IMPACT of Magnets), a retrospective, multicenter study of children with high-powered magnet exposures (ie, ingestion or bodily insertion), were contacted. Consenting participants responded to a standardized questionnaire regarding the presence and utility of warning labels, magnet product manufacturer, and attitudes around risk.

RESULTS

Of 596 patients in the IMPACT study, 173 parents and 1 adult patient were reached and consented to participate. The median age was 7.5 years. Subjects reported not knowing if a warning label was present in 60 (53.6%) cases, whereas 25 (22.3%) stated warnings were absent. Warnings were present in 28 (24.1%) cases but only 13 (46.4%) reported reading them. A manufacturer was identified by families in 28 (16.1%) exposures; 25 of these were domestic and 27 had warnings. Subjects reported knowing magnets were dangerous in 58% of the cases, although 44.3% believed they were children's toys and only 6.9% knew high-powered magnets were previously removed from the United States market.

CONCLUSIONS

Over 90% of subjects from the IMPACT study didn't know if warning labels were present or failed to read them if they were, whereas almost half believed high-powered magnets were children's toys. Warning labels on high-powered magnet products are, therefore, unlikely to prevent injuries in children.

High-Powered Magnet Exposures in Children: A Multi-Center Cohort Study

BACKGROUND AND OBJECTIVES

High-powered magnets were effectively removed from the US market by the Consumer Product Safety Commission (CPSC) in 2012 but returned in 2016 after federal court decisions. The United States Court of Appeals for the 10th Circuit cited imprecise data among other reasons as justification for overturning CPSC protections. Since then, incidence of high-powered magnet exposure has increased markedly, but outcome data are limited. In this study, we aim to describe the epidemiology and outcomes in children seeking medical care for high-powered magnets after reintroduction to market.

METHODS

This is a multicenter, retrospective cohort study of patients aged 0 to 21 years with a confirmed high-powered magnet exposure (ie, ingestion or insertion) at 25 children's hospitals in the United States between 2017 and 2019.

RESULTS

Of 596 patients with high-powered magnet exposures identified, 362 (60.7%) were male and 566 (95%) were <14 years of age. Nearly all sought care for magnet ingestion (n = 574, 96.3%), whereas 17 patients (2.9%) presented for management of nasal or aural magnet foreign bodies, 4 (0.7%) for magnets in their genitourinary tract, and 1 patient (0.2%) had magnets in their respiratory tract. A total of 57 children (9.6%) had a life-threatening morbidity; 276 (46.3%) required an endoscopy, surgery, or both; and 332 (55.7%) required hospitalization. There was no reported mortality.

CONCLUSIONS

Despite being intended for use by those >14 years of age, high-powered magnets frequently cause morbidity and lead to high need for invasive intervention and hospitalization in children of all ages.

Vitamin D Is Associated with α4β7+ Immunophenotypes and Predicts Vedolizumab Therapy Failure in Patients with Inflammatory Bowel Disease

BACKGROUND AND AIMS

Vitamin D downregulates the in vitro expression of the gut-tropic integrin α4β7 on immune cells. The clinical relevance of this finding in patients with inflammatory bowel disease [IBD] is unclear. We tested the hypothesis that vitamin D is associated with α4β7 immunophenotypes and risk of vedolizumab [anti-α4β7] failure in IBD.

METHODS

We performed single-cell immunophenotyping of peripheral and intestinal immune cells using mass cytometry [CyTOF] in vedolizumab-naïve patients with IBD [N = 48]. We analysed whole-genome mucosal gene expression [GSE73661] from GEMINI I and GEMINI long-term safety [LTS] to determine the association between vitamin D receptor [VDR] and integrin alpha-4 [ITGA4] and beta-7 [ITGB7] genes. We estimated the odds of vedolizumab failure with low pre-treatment vitamin D in a combined retrospective and prospective IBD cohort [N = 252] with logistic regression.

RESULTS

Immunophenotyping revealed that higher 25[OH]D was associated with decreased α4β7+ peripheral blood mononuclear cells [R = -0.400, p <0.01] and α4β7+ intestinal leukocytes [R = -0.538, p = 0.03]. Serum 25[OH]D was inversely associated with α4β7+ peripheral B cells and natural killer [NK] cells and α4β7+ intestinal B cells, NK cells, monocytes, and macrophages. Mucosal expression of VDR was inversely associated with ITGA4 and ITGB7 expression. In multivariate analysis, 25[OH]D <25 ng/mL was associated with increased vedolizumab primary non-response during induction (odds ratio [OR] 26.10, 95% confidence interval [CI] 14.30-48.90, p <0.001) and failure at 1-year follow-up [OR 6.10, 95% CI 3.06-12.17, p <0.001].

CONCLUSIONS

Low serum 25[OH]D is associated with α4β7+ immunophenotypes and predicts future vedolizumab failure in patients with IBD.

PODCAST

This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Artificial intelligence applications in inflammatory bowel disease: Emerging technologies and future directions

Inflammatory bowel disease (IBD) is a complex and multifaceted disorder of the gastrointestinal tract that is increasing in incidence worldwide and associated with significant morbidity. The rapid accumulation of large datasets from electronic health records, high-definition multi-omics (including genomics, proteomics, transcriptomics, and metagenomics), and imaging modalities (endoscopy and endomicroscopy) have provided powerful tools to unravel novel mechanistic insights and help address unmet clinical needs in IBD. Although the application of artificial intelligence (AI) methods has facilitated the analysis, integration, and interpretation of large datasets in IBD, significant heterogeneity in AI methods, datasets, and clinical outcomes and the need for unbiased prospective validations studies are current barriers to incorporation of AI into clinical practice. The purpose of this review is to summarize the most recent advances in the application of AI and machine learning technologies in the diagnosis and risk prediction, assessment of disease severity, and prediction of clinical outcomes in patients with IBD.

Lysosomal Disorders Drive Susceptibility to Tuberculosis by Compromising Macrophage Migration

A zebrafish genetic screen for determinants of susceptibility to Mycobacterium marinum identified a hypersusceptible mutant deficient in lysosomal cysteine cathepsins that manifests hallmarks of human lysosomal storage diseases. Under homeostatic conditions, mutant macrophages accumulate undigested lysosomal material, which disrupts endocytic recycling and impairs their migration to, and thus engulfment of, dying cells. This causes a buildup of unengulfed cell debris. During mycobacterial infection, macrophages with lysosomal storage cannot migrate toward infected macrophages undergoing apoptosis in the tuberculous granuloma. The unengulfed apoptotic macrophages undergo secondary necrosis, causing granuloma breakdown and increased mycobacterial growth. Macrophage lysosomal storage similarly impairs migration to newly infecting mycobacteria. This phenotype is recapitulated in human smokers, who are at increased risk for tuberculosis. A majority of their alveolar macrophages exhibit lysosomal accumulations of tobacco smoke particulates and do not migrate to Mycobacterium tuberculosis. The incapacitation of highly microbicidal first-responding macrophages may contribute to smokers’ susceptibility to tuberculosis.

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Lysosomal storage diseases reduce macrophage endocytic recycling and migration

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Reduced macrophage migration increases tuberculosis severity via granuloma breakdown

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Tobacco smoke particles accumulate in lysosomes of smokers’ alveolar macrophages

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Lysosomal particles reduce smokers’ macrophage migration to infecting mycobacteria

mTOR deficiency reveals an immunological trade-off in innate resistance to mycobacterial infection in vivo

The Mechanistic Target of Rapamycin (mTOR) has been implicated in myeloid cell development and survival. As adequate myelopoiesis has been recently shown to be a resistance factor in tuberculosis, mTOR deficiency would be expected to increase mycobacterial growth and thus host susceptibility to this disease. In contrast, mTOR inhibition decreases Mycobacterium tuberculosis infection burdens in cultured macrophages, an effect attributed to the triggering of autophagy. Which of these contradictory effects of mTOR deficiency influences infection outcome in vivo is unknown. We have examined the effects of mTOR on mycobacterial infection using the optically transparent and genetically tractable Mycobacterium marinum-zebrafish model of tuberculosis. A forward genetic screen in zebrafish initially identified an mtor mutant as being hypersusceptible to M. marinum, a phenotype that mapped to mTOR complex 1 and was reproduced with rapamycin. However, using very low inoculums typical of human tuberculosis (1–3 mycobacteria) revealed mTOR’s dichotomous role: mTOR-deficient animals were more likely to clear infection early, but those that did not clear the infection progressed rapidly to more severe disease characterized by the death of infected macrophages and subsequent release of mycobacteria into the more growth-permissive extracellular space. Thus, mTOR supports macrophage homeostasis at the expense of a transient enhancement in microbicidal capacity that could reduce the likelihood of mycobacterial colonization but would inevitably thwart long-term immunity.