The Impact of Vitamin D on Response to Anti-tumor Necrosis Factor-α Therapy in Children With Inflammatory Bowel Disease

Cellular and Molecular Determinants of Biologic Drugs Resistance and Therapeutic Failure in Inflammatory Bowel Disease

The advent of biologic drugs has revolutionized the treatment of Inflammatory Bowel Disease, increasing rates of response and mucosal healing in comparison to conventional therapies by allowing the treatment of corticosteroid-refractory cases and reducing corticosteroid-related side effects. However, biologic therapies (anti-TNFα inhibitors, anti-α4β7 integrin and anti-IL12/23) are still burdened by rates of response that hover around 40% (in biologic-naïve patients) or lower (for biologic-experienced patients). Moreover, knowledge of the mechanisms underlying drug resistance or loss of response is still scarce. Several cellular and molecular determinants are implied in therapeutic failure; genetic predispositions, in the form of single nucleotide polymorphisms in the sequence of cytokines or Human Leukocyte Antigen, or an altered expression of cytokines and other molecules involved in the inflammation cascade, play the most important role. Accessory mechanisms include gut microbiota dysregulation. In this narrative review of the current and most recent literature, we shed light on the mentioned determinants of therapeutic failure in order to pave the way for a more personalized approach that could help avoid unnecessary treatments and toxicities.

Correlation between Treatment Outcomes and Serum Vitamin D Levels As Well As Infliximab Trough Concentration among Chinese Patients with Crohn's Disease

Background

The relationship between vitamin D (vit-D) levels and the effectiveness of infliximab (IFX) in patients with Crohn's disease (CD) remains controversial.

Objective

To evaluate the interaction between vit-D levels and the response to IFX therapy in patients with CD.

Methods

This was a retrospective cohort study. Serum vit-D and IFX trough concentrations (TC) were measured in 84 patients, and statistical analyses were performed.

Results

The total vit-D deficiency rate at enrollment, at week 14 and week 38, was 64.3%, 41.67%, and 37.5%, respectively (P < 0.001). CD activity index (CDAI) (120, range, 93-142.75) and simplified endoscopic activity score for CD (SES-CD) (2, range, 0-4) at week 14 were lower than that of enrollment (CDAI, 136.5, range, 101.25-196; SES-CD 13, range, 5-23) (P < 0.001). The biochemical remission (BR), clinical remission (CR), endoscopic remission (ER), and response (ERe) rates of week 38 were 76.1%, 88.5%, 22.4%, and 67.2%, respectively. vit-D levels at enrollment were positively correlated with CDAI at week 38 (P = 0.024). IFX serum TC was related to BR (P = 0.036), CR (P = 0.032) at week 14, and ERe (P = 0.009) at week 38.

Conclusion

Among Chinese patients with CD, vit-D levels prior to IFX therapy are related to CDAI scores, and IFX serum TC is associated with BR, CR, and ERe.

[Mechanism of action and exogenous supplementation of vitamin D in Crohn's disease]

Vitamin D can not only regulate calcium and phosphorus metabolism, but also exert an immunoregulatory effect. Vitamin D deficiency is common in patients with Crohn's disease (CD). Studies have shown that vitamin D is associated with CD and other autoimmune diseases and can improve the condition of patients with CD and promote their recovery by regulating intestinal immunity, repairing the intestinal mucosal barrier, inhibiting intestinal fibrosis, enhancing the response to infliximab, and regulating intestinal microbiota. Exogenous vitamin D supplementation can induce disease remission while increasing the serum level of vitamin D. However, only a few randomized, double-blind, and placebo-controlled trials have investigated the therapeutic effect of vitamin D in CD, and the optimal form of vitamin D supplementation, the specific dosage of vitamin D supplementation, and the optimal serum maintenance concentration of vitamin D remain to be clarified. This article mainly discusses the mechanism of action of vitamin D in CD and the beneficial effect of exogenous vitamin D supplementation on CD.

Rising Incidence of Inflammatory Bowel Disease in South Asian Children in New Zealand-A Retrospective Population-Based Study

OBJECTIVES

High rates of inflammatory bowel disease (IBD) are reported in children of South Asian (SA) descent in some western countries. This population-based study describes the incidence and clinical course of IBD in SA children compared to non-South Asian (NSA) children in New Zealand (NZ).

METHODS

Children (≤15 years) with new-onset IBD presenting to a centralized tertiary referral center in Auckland, NZ from 2010 to 2020 were identified. Disease phenotype, clinical characteristics, response to exclusive enteral nutrition, clinical remission rates at 3 and 12 months, biologic use, corticosteroid exposure, and disease complications were compared by ethnicity; IBD incidence was calculated.

RESULTS

There were 127 (26 SA; 101 NSA) children with Crohn disease, 41 (10 SA; 31 NSA) with ulcerative colitis, and 10 (3 SA; 7 NSA) with IBD-unclassified. IBD incidence in SA and NSA children was 14.1 per 100,000 and 4.3 per 100,000 respectively ( P < 0.001). IBD incidence increased by 5.6% per year ( P = 0.022), due to a greater rise in incidence in SA (SA 16.8% per year, P = 0.015; NSA 4.5% per year, P = 0.317). At presentation, SA children had worse biochemical parameters, severe colitis, and vitamin D deficiency. SA children had lower rates of remission following exclusive enteral nutrition (28.5% vs 65.0%, P < 0.001) or biologic induction (35.7% vs 70.8%, P = 0.020), at 3-month (35.3% vs 69.8%, P < 0.001) and 12-month follow-up (29.4% vs 55.0%, P = 0.005). No significant differences were found in disease location or corticosteroid burden.

CONCLUSIONS

Increasing incidence of IBD was disproportionately represented by SA children with more severe disease and lower remission rates following exclusive enteral nutrition or biologic therapy.

Adjunctive therapeutic effects of micronutrient supplementation in inflammatory bowel disease

Growing evidence suggests that micronutrient status may have some impact on the course of inflammatory bowel disease (IBD). However, micronutrient deficiencies are easily overlooked during the treatment of IBD patients. There have been many studies on micronutrient supplementation, in which several clinical trials have been conducted targeting vitamin D and iron, but the current research is still preliminary for other vitamins and minerals. This review provides an overview of the adjunctive therapeutic effects of micronutrient supplementation in IBD, to summarize the available evidence, draw the attention of clinicians to micronutrient monitoring and supplementation in patients with IBD, and also provide some perspectives for future research directions.

The Role of Vitamin D in Immune System and Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a nonspecific inflammatory disease that includes ulcerative colitis (UC) and Crohn’s disease (CD). The pathogenesis of IBD is not fully understood but is most reported associated with immune dysregulation, dysbacteriosis, genetic susceptibility, and environmental risk factors. Vitamin D is an essential nutrient for the human body, and it not only regulates bone metabolism but also the immune system, the intestinal microbiota and barrier. Vitamin D insufficiency is common in IBD patients, and the abnormal low levels of vitamin D are highly correlated with disease activity, treatment response, and risk of relapse of IBD. Accumulating evidence supports the protective role of vitamin D in IBD through regulating the adaptive and innate immunity, maintaining the intestinal barrier and balancing the gut microbiota. This report aims to provide a broad overview of the role vitamin D in the immune system, especially in the pathogenesis and treatment of IBD, and its possible role in predicting relapse.

Vitamin D: Dosing, levels, form, and route of administration: Does one approach fit all?

The 4^th International Conference on Controversies in Vitamin D was held as a virtual meeting in September, 2020, gathering together leading international scientific and medical experts in vitamin D. Since vitamin D has a crucial role in skeletal and extra-skeletal systems, the aim of the Conference was to discuss improved management of vitamin D dosing, therapeutic levels and form or route of administration in the general population and in different clinical conditions. A tailored approach, based on the specific mechanisms underlying vitamin D deficiency in different diseases that were discussed, was recommended. Specifically, in comparison to healthy populations, higher levels of vitamin D and greater amounts of vitamin D were deemed necessary in osteoporosis, diabetes mellitus, obesity (particularly after bariatric surgery), and in those treated with glucocorticoids. Emerging and still open issues were related to target vitamin D levels and the role of vitamin D supplementation in COVID-19 since low vitamin D may predispose to SARS-CoV-2 infection and to worse COVID-19 outcomes. Finally, whereas oral daily cholecalciferol appears to be the preferred choice for vitamin D supplementation in the general population, and in most clinical conditions, active vitamin D analogs may be indicated in patients with hypoparathyroidism and severe kidney and liver insufficiency. Parenteral vitamin D administration could be helpful in malabsorption syndromes or in states of vitamin D resistance.Specific guidelines for desired levels of vitamin D should be tailored to the different conditions affecting vitamin D metabolism with the goal to define disease-specific normative values.

Biomarkers for Optimization and Personalization of Anti-TNFs in Pediatric Inflammatory Bowel Disease

The use of biological drugs has improved outcomes in pediatric inflammatory bowel disease (IBD). Prediction of the response to biological drugs would be extremely useful in IBD, and even more so in children, who are still growing physically and psychologically. Specific clinical, biochemical, and genetic parameters are considered predictive of response to biological drugs, although few studies have been carried out in children with IBD. In this review, we present current evidence on biological treatments used in pediatric IBD and the available biomarkers of response. We examine demographics, clinical characteristics, biomarkers (genetic, genomic, and cellular), and microbiota.