Association of linear growth impairment in pediatric Crohn's disease and a known height locus: a pilot study

Current perspectives on pediatric inflammatory bowel disease focusing on transitional care management. What should we consider?

The prevalence of inflammatory bowel disease (IBD) continues to rise around the globe. Although the percentage of pediatric IBD patients seems to be increasing, rates are surprisingly heterogeneous among different populations. Although the pathogenesis of IBD is believed to be multifactorial, a genetic predisposition may be especially relevant in pediatric-onset IBD. Phenotypic characteristics can also be significantly different when comparing pediatric and adult-onset IBD. Patients that develop the disease at a younger age usually present with more extensive and more aggressive disease and develop complications faster when compared to those that develop it during adulthood. Children with IBD are found to have frequent mood disorders and have a higher risk of developing socio-economic hardship, failing to meet development milestones. Therefore, IBD management should always involve a multidisciplinary team that is not limited to medical providers. Most institutions do not have an established transition protocol and lack the resources and training for transition care. Although there is no consensus on an optimal timing to transition the patient's care to an adult team, it is usually accepted they should be eligible for adult care when most of the key transition points have been met. Management strategies should be tailored to each patient's developmental level and environment. A successful transition can improve the long-term outcomes such as sustained remission, medication adherence, mental health and social and academic performance, while decreasing healthcare utilization. Every institution that manages pediatric IBD patients should have a well-established transition protocol in order to make sure to maintain continuity of care.

ILRUN Downregulates ACE2 Expression and Blocks Infection of Human Cells by SARS-CoV-2

The human protein-coding gene ILRUN (inflammation and lipid regulator with UBA-like and NBR1-like domains; previously C6orf106) was identified as a proviral factor for Hendra virus infection and was recently characterized to function as an inhibitor of type I interferon expression. Here, we have utilized transcriptome sequencing (RNA-seq) to define cellular pathways regulated by ILRUN in the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of Caco-2 cells. We find that inhibition of ILRUN expression by RNA interference alters transcription profiles of numerous cellular pathways, including upregulation of the SARS-CoV-2 entry receptor ACE2 and several other members of the renin-angiotensin aldosterone system. In addition, transcripts of the SARS-CoV-2 coreceptors TMPRSS2 and CTSL were also upregulated. Inhibition of ILRUN also resulted in increased SARS-CoV-2 replication, while overexpression of ILRUN had the opposite effect, identifying ILRUN as a novel antiviral factor for SARS-CoV-2 replication. This represents, to our knowledge, the first report of ILRUN as a regulator of the renin-angiotensin-aldosterone system (RAAS). IMPORTANCE There is no doubt that the current rapid global spread of COVID-19 has had significant and far-reaching impacts on our health and economy and will continue to do so. Research in emerging infectious diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is growing rapidly, with new breakthroughs in the understanding of host-virus interactions to assist with the development of innovative and exciting therapeutic strategies. Here, we present the first evidence that modulation of the human protein-coding gene ILRUN functions as an antiviral factor for SARS-CoV-2 infection, likely through its newly identified role in regulating the expression of SARS-CoV-2 entry receptors ACE2, TMPRSS2, and CTSL. These data improve our understanding of biological pathways that regulate host factors critical to SARS-CoV-2 infection, contributing to the development of antiviral strategies to deal with the current SARS-CoV-2 pandemic.

The Association of ATG16L1 Variations with Clinical Phenotypes of Adult-Onset Still's Disease

Adult-onset Still’s disease (AOSD) is a rare autoinflammatory disease, which has elevated autophagosome levels regulated by autophagy-related gene (ATG) expression. We investigated the associations of ATG polymorphisms with AOSD susceptibility, clinical manifestations, and disease course. The six-candidate single-nucleotide polymorphisms (SNPs) involved in autophagy were genotyped using direct sequencing on samples from 129 AOSD patients and 129 healthy participants. The differentially expressed gene products were quantified using PCR and ELISA. Significant linkage disequilibrium was noted in three SNPs of autophagy-related 16-like 1 (ATG16L1) gene (rs10210302, rs2241880, and rs1045100). Although the AA/CC/TT haplotype of ATG16L1 was not associated with the susceptibility of our AOSD patients compared with other haplotypes, those carrying this haplotype had lower mRNA expression levels of LC3-II, reflecting by autophagosome formation (p = 0.026). Patients carrying AA/CC/TT haplotype also have a significantly higher proportion of skin rash and a lower proportion of arthritis compared with other haplotypes. The AA/CC/TT haplotype was significantly associated with systemic pattern (odds ratio, 3.25; 95% confidence interval, 1.15–9.14; p = 0.026). In summary, the AA/CC/TT haplotype encoded lower levels of autophagosome formation and was associated with a higher proportion of skin rash and systemic pattern of AOSD compared with other haplotypes.

Growth and Puberty in Children with Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are gastrointestinal tract pathologies of unknown etiology; they have an alternating trend, with active and silent phases. IBD are classified in two main forms: ulcerative colitis (UC) and Crohn’s disease (CD). Both have chronic and recurrent course, gastrointestinal symptoms, and extraintestinal manifestations. The altered immune response role seems to be important both in UC and CD. In the majority of cases, CD begins with abdominal pain, diarrhea, decrease in appetite, and weight loss; there can be also perianal fistulas, rhagades, and perianal recurrent abscesses. In addition, retarded growth and delayed puberty can precede the development of the disease or can even be predominant at onset. Growth retardation is found in 40% of IBD patients, but the underlying mechanism of this and other extra-intestinal manifestations are partially known: the main hypotheses are represented by malnutrition and inflammatory response during the active phase of the disease. The increased level of pro-inflammatory cytokines can influence growth, but also the onset of puberty and its progression. In addition, it could be essential to clarify the role and the possible effects of all the currently used treatments concerning growth failure and delayed puberty.

Molecular characterisation of ILRUN, a novel inhibitor of proinflammatory and antimicrobial cytokines

Regulation of type-I interferon (IFN) production is essential to the balance between antimicrobial defence and autoimmune disorders. The human protein-coding gene ILRUN (inflammation and lipid regulator with UBA-like and NBR1-like domains, previously C6orf106) was recently characterised as an inhibitor of antiviral and proinflammatory cytokine (interferon-alpha/beta and tumor necrosis factor alpha) transcription. Currently there is a paucity of information about the molecular characteristics of ILRUN, despite it being associated with several diseases including virus infection, coronary artery disease, obesity and cancer. Here, we characterise ILRUN as a highly phylogenetically conserved protein containing UBA-like and a NBR1-like domains that are both essential for inhibition of type-I interferon and tumor necrosis factor alpha) transcription in human cells. We also solved the crystal structure of the NBR1-like domain, providing insights into its potential role in ILRUN function. This study provides critical information for future investigations into the role of ILRUN in health and disease.

Long-term outcome of immunomodulator use in pediatric patients with inflammatory bowel disease

OBJECTIVES

In the era where new biologicals are entering the market, the place of immunomodulators in the treatment of pediatric inflammatory bowel disease (IBD) needs to be reassessed.

METHODS

All children with Crohn's disease (CD) or ulcerative colitis (UC) followed at our center over the last 10 years were reviewed. Children who received conventional therapy (including 5-aminosalicylates, steroids, thiopurines and methotrexate) since diagnosis were included. Primary outcome was steroid-free clinical remission without need for rescue therapy (biologics or surgery) at 6 and 12 months after diagnosis and at last follow-up. Cox proportional hazard modelling was performed to determine variables at diagnosis associated with outcomes.

RESULTS

In total, 176 IBD patients (121 CD, 55 UC) were identified with a median follow-up of 4.6 [2.0-8.1] years. Remission rates were 79.6% at month 6, but decreased to 60.2% at month 12, and 31.8% at last follow-up. Higher CRP [1.006 (1.001-1.011)], lower albumin [1.050 (1.012-1.086)] and growth impairment [1.214 (1.014-1.373)] in CD patients and higher PUCAI score [1.038 (1.006-1.072)] and low iron [1.023 (1.003-1.043)] in UC patients were associated with treatment failure (all p < 0.05).

CONCLUSION

Only 32% pediatric IBD patients will remain free of biologics or surgery 5-years after diagnosis. Especially children with a high disease burden at diagnosis were more likely to fail conventional therapy.

Growth failure in pediatric onset inflammatory bowel disease: mechanisms, epidemiology, and management

Impairment of growth is recognized as one of the most significant complications of inflammatory bowel disease (IBD) in pediatric patients. The reported incidence of growth failure at diagnosis is 15-40% in pediatric onset Crohn's disease (CD) and 3-10% in ulcerative colitis (UC). Growth failure is associated with decreased appetite, abdominal symptoms, malabsorption due to mucosal inflammation, growth hormone (GH) resistance due to inflammation, and even genetic factors. Several population-based studies and cohort studies suggest that patients with pre-pubertal onset CD have a higher risk of growth failure at disease onset. Final adult height is still lower than that of healthy controls; however, its prevalence is generally lower than that at the disease onset. Several IBD treatments were reported to improve patients' growth. In addition to enteral nutrition therapy, treatment with anti-tumor necrosis factor (TNF) agents was reported to have favorable effects on growth of patients with pre-pubertal onset CD. Avoiding corticosteroids (CS) and achieving deep remission seems to be important to maintain optimal growth in patients with pediatric onset IBD.

Nutrition in Pediatric Inflammatory Bowel Disease: A Position Paper on Behalf of the Porto Inflammatory Bowel Disease Group of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND AND AIMS

A growing body of evidence supports the need for detailed attention to nutrition and diet in children with inflammatory bowel disease (IBD). We aimed to define the steps in instituting dietary or nutritional management in light of the current evidence and to offer a useful and practical guide to physicians and dieticians involved in the care of pediatric IBD patients.

METHODS

A group of 20 experts in pediatric IBD participated in an iterative consensus process including 2 face-to-face meetings, following an open call to Nutrition Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition Porto, IBD Interest, and Nutrition Committee. A list of 41 predefined questions was addressed by working subgroups based on a systematic review of the literature.

RESULTS

A total of 53 formal recommendations and 47 practice points were endorsed with a consensus rate of at least 80% on the following topics: nutritional assessment; macronutrients needs; trace elements, minerals, and vitamins; nutrition as a primary therapy of pediatric IBD; probiotics and prebiotics; specific dietary restrictions; and dietary compounds and the risk of IBD.

CONCLUSIONS

This position paper represents a useful guide to help the clinicians in the management of nutrition issues in children with IBD.

Growth and the Growth Hormone-Insulin Like Growth Factor 1 Axis in Children With Chronic Inflammation: Current Evidence, Gaps in Knowledge, and Future Directions

Growth failure is frequently encountered in children with chronic inflammatory conditions like juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis. Delayed puberty and attenuated pubertal growth spurt are often seen during adolescence. The underlying inflammatory state mediated by proinflammatory cytokines, prolonged use of glucocorticoid, and suboptimal nutrition contribute to growth failure and pubertal abnormalities. These factors can impair growth by their effects on the GH-IGF axis and also directly at the level of the growth plate via alterations in chondrogenesis and local growth factor signaling. Recent studies on the impact of cytokines and glucocorticoid on the growth plate further advanced our understanding of growth failure in chronic disease and provided a biological rationale of growth promotion. Targeting cytokines using biological therapy may lead to improvement of growth in some of these children, but approximately one-third continue to grow slowly. There is increasing evidence that the use of relatively high-dose recombinant human GH may lead to partial catch-up growth in chronic inflammatory conditions, although long-term follow-up data are currently limited. In this review, we comprehensively review the growth abnormalities in children with juvenile idiopathic arthritis, inflammatory bowel disease, and cystic fibrosis, systemic abnormalities of the GH-IGF axis, and growth plate perturbations. We also systematically reviewed all the current published studies of recombinant human GH in these conditions and discussed the role of recombinant human IGF-1.

Impaired growth and puberty in pediatric patients with inflammatory bowel disease: Etiology and treatment

Growth failure associated with delayed puberty is a unique feature in pediatric patients with inflammatory bowel disease (IBD), especially those with Crohn's disease, which has a negative effect on quality of life, emotional functioning, social functioning, and body image. Although the underlying mechanisms are not fully clear, the condition may be induced by the effects of malnutrition, inflammatory process and glucocorticoid on the growth hormone/insulin-like growth factor-1 axis or on the growth plate. Nutrition, biologic agents, intestinal resection and glucocorticoids are main treatments. Standards for monitoring and treatment of impaired growth and development in pediatric IBD patients need to be formulated. To achieve optimal growth, the efforts of hospitals, families and society are necessary.

Genome-wide interrogation of longitudinal FEV1 in children with asthma

RATIONALE

Most genomic studies of lung function have used phenotypic data derived from a single time-point (e.g., presence/absence of disease) without considering the dynamic progression of a chronic disease.

OBJECTIVES

To characterize lung function change over time in subjects with asthma and identify genetic contributors to a longitudinal phenotype.

METHODS

We present a method that models longitudinal FEV1 data, collected from 1,041 children with asthma who participated in the Childhood Asthma Management Program. This longitudinal progression model was built using population-based nonlinear mixed-effects modeling with an exponential structure and the determinants of age and height.

MEASUREMENTS AND MAIN RESULTS

We found ethnicity was a key covariate for FEV1 level. Budesonide-treated children with asthma had a slight but significant effect on FEV1 when compared with those treated with placebo or nedocromil (P < 0.001). A genome-wide association study identified seven single-nucleotide polymorphisms nominally associated with longitudinal lung function phenotypes in 581 white Childhood Asthma Management Program subjects (P < 10(-4) in the placebo ["discovery"] and P < 0.05 in the nedocromil treatment ["replication"] group). Using ChIP-seq and RNA-seq data, we found that some of the associated variants were in strong enhancer regions in human lung fibroblasts and may affect gene expression in human lung tissue. Genetic mapping restricted to genome-wide enhancer single-nucleotide polymorphisms in lung fibroblasts revealed a highly significant variant (rs6763931; P = 4 × 10(-6); false discovery rate < 0.05).

CONCLUSIONS

This study offers a strategy to explore the genetic determinants of longitudinal phenotypes, provide a comprehensive picture of disease pathophysiology, and suggest potential treatment targets.

Growth problems in children with IBD

Crohn's disease in childhood causes linear growth retardation, which has a substantial effect on management of this disease. By contrast, growth is rarely a problem in children presenting with ulcerative colitis. Depending on how growth failure is defined, approximately one-third of children with Crohn's disease have growth retardation at diagnosis. Although corticosteroids can suppress growth, decreased height at diagnosis demonstrates that this finding is a consequence of the disease and not merely an adverse effect of treatment. Both inflammation and undernutrition contribute to decreased height velocity. Increased cytokine production acts both on the hepatic expression of insulin-like growth factor 1 (IGF-1) and at chondrocytes of the growth plates of long bones. Growth hormone insensitivity caused by deranged immune function is a major mechanism in growth retardation. Resolution of inflammation is the cornerstone of treatment, but current studies on growth hormone and IGF-1 might yield therapies for those children whose inflammation is refractory to treatment.

Inflammatory cytokines and growth in childhood

PURPOSE OF REVIEW

In this review we report an update on the current knowledge on growth disorders in children with chronic inflammatory diseases, mainly inflammatory bowel disease and juvenile idiopathic arthritis, with a particular focus on the role of inflammatory cytokines as mediators of growth impairment.

RECENT FINDINGS

Growth disorders are common among patients with inflammatory diseases. Several factors can contribute to growth failure: poor nutrition, immobilization, drugs, disease activity, duration and severity. There is extensive evidence suggesting that inflammatory cytokines are key players in mediating growth failure. Recent studies have confirmed a direct association between levels of inflammatory cytokines, such as tumour necrosis factor-α and interleukin-6, and reduced growth velocity, as well as impaired body composition. Recent studies have also highlighted the beneficial effect of new drugs, such biologics, not only in controlling disease activity, but also in improving growth.

SUMMARY

Growth retardation remains a major problem in patients with chronic inflammatory diseases, and proinflammatory cytokines are key players in this context. New drugs, specifically targeting inflammatory cytokines appear to be promising for their effect on growth. Further studies are required to better characterize the cytokine profile in children with inflammatory disease and help in developing effective treatment strategies.

Sex differences in statural growth impairment in Crohn's disease: role of IGF-1

BACKGROUND

Growth impairment in Crohn's disease (CD) is more common in males than females for unknown reasons. Since insulin-like growth factor-1 (IGF-1) is important for statural growth, we hypothesized that IGF-1 levels are lower in males with CD.

METHODS

Sex differences in hormone Z-scores based on chronological age (CA-Z) and bone age (BA-Z) were examined in a cross-sectional study of 82 CD patients <21 years of age (43% female).

RESULTS

IGF-1 CA-Z and BA-Z-scores were 0.50 units (P = 0.04) and 1.24 units (P = 0.003) lower in males. Mean bone age (12.2 years) was lower than chronological age (13.1 years) (P < 0.0001). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and albumin did not differ by sex (P ≥ 0.08), but were associated with IGF-1 CA-Z and BA-Z-scores (P ≤ 0.02). Insulin-like growth factor binding protein-3 (IGFBP-3) CA-Z and BA-Z-scores were 0.71 units (P = 0.004) and 1.26 units (P < 0.001) lower in males. Inflammatory markers were correlated with sex hormone CA-Z and BA-Z and pituitary hormone BA-Z-scores in males (P ≤ 0.03), but not females (P ≥ 0.25). IGF-1 BA-Z-scores were positively associated with height BA-Z-scores (P = 0.03). Mean height BA-Z-scores were lower in males (P = 0.03).

CONCLUSIONS

Lower IGF-1 levels in males may explain sex differences in growth impairment in CD. Inflammation appears to more adversely affect hormone levels and statural growth in males. Prospective longitudinal studies are needed to further clarify the role of IGF-1 in sex differences in statural growth impairment in pediatric CD.

Marco Ramoni: an appreciation of academic achievement

We review the scholarly career of our colleague, Marco Ramoni, who died unexpectedly in the summer of 2010. His work mainly explored the development and application of Bayesian techniques to model clinical, public health, and bioinformatics questions. His contributions have led to improvements in our ability to model behavior that evolves in time, to explore systematic relationships among large sets of covariates, and to tease out the meaning of data on the role of genetic variation in the genesis of important diseases.

Impact of Inflammatory Bowel Disease upon Growth in Children and Adolescents

The inflammatory bowel diseases (IBDs) are chronic inflammatory processes affecting the gastrointestinal tract. When diagnosed in childhood and adolescence, IBD almost always impacts adversely upon the nutritional state of the patient. Weight loss and impaired linear growth may be present at diagnosis or subsequently. Further potential nutritional consequences in childhood IBD include malnutrition, anaemia, osteopaenia, and delayed puberty. Understanding the nutritional aspects of IBD is paramount in growing children, especially those entering and advancing through puberty. This paper focuses upon the nutritional impacts of IBD in children and adolescents.