Inflammatory cytokines in juvenile idiopathic arthritis: effects on physical growth and the insulin-like-growth factor axis

Tocilizumab for juvenile idiopathic arthritis: a single-center case series

BACKGROUND

Juvenile idiopathic arthritis (JIA) is the commonest chronic rheumatic disease among children. When not treated effectively, JIA can lead to functional disability, due to joint damage, along with long-term morbidities.

OBJECTIVES

To describe the use of tocilizumab therapy for 11 patients with polyarticular JIA (pJIA) and systemic JIA (sJIA) who presented inadequate response or were refractory to disease-modifying anti-rheumatic drugs (DMARDs) and/or other biological therapies; and to evaluate its benefits, safety and tolerability.

DESIGN AND SETTING

Observational retrospective case series at a tertiary-level training and research hospital.

METHODS

We reviewed the medical records of 11 consecutive patients with JIA who received tocilizumab (anti-IL-6) therapy in our pediatric nephrology and rheumatology outpatient clinic. We analyzed their demographic data, clinical and laboratory findings, treatment response and adverse reactions. We determined the efficacy of tocilizumab treatment using the American College of Rheumatology (ACR) pediatric (Pedi) response criteria, including ACR Pedi 30, 50, 70 and 90 scores. We used the Wilcoxon test to compare measurements before and after treatment.

RESULTS

Tocilizumab was given to seven patients with sJIA and four with pJIA (one of the pJIA patients was rheumatoid factor-positive). In most patients, we observed improvement of symptoms, absence of articular and extra-articular inflammation and continued inactive disease. ACR Pedi 30, 50 and 70 scores were achieved by 90.9% of the patients. Five patients showed minor side effects, possibly due to use of tocilizumab.

CONCLUSIONS

Tocilizumab therapy should be considered for treating patients with diagnoses of pJIA or sJIA who are resistant to non-biological DMARDs and/or other biological therapies.

Insulin-Like Growth Factor Binding Proteins in Autoimmune Diseases

Insulin-like growth factor binding proteins (IGFBPs) are a family of proteins binding to Insulin-like growth factors (IGFs), generally including IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, and IGFBP6. The biological functions of IGFBPs can be classified as IGFs-dependent actions and IGFs-independent effects. In this review, we will discuss the structure and function of various IGFBPs, particularly IGFBPs as potential emerging biomarkers and therapeutic targets in various autoimmune diseases, and the possible mechanisms by which IGFBPs act on the pathogenesis of autoimmune diseases.

Growth Outcomes After GH Therapy of Patients Given Long-Term Corticosteroids for Juvenile Idiopathic Arthritis

CONTEXT

Growth hormone (GH) therapy may improve statural growth outcomes in patients with severe juvenile idiopathic arthritis (JIA).

OBJECTIVES

To evaluate the effect of GH treatment on adult height and to identify determinants of growth outcomes in JIA.

DESIGN AND PATIENTS

Data from 58 patients with JIA, including 53 receiving GH, enrolled in three prospective clinical trials between 1997 and 2002 were analyzed.

INTERVENTION

GH (0.056 mg/kg/d [interquartile range (IQR), 0.050 to 0.062]) for a median duration of 6.5 years (IQR, 4.7 to 7.9 years).

MAIN OUTCOME MEASURES

Factors associated with a favorable growth outcome (adult height - target height ≤ -1.5 standard deviations) were identified by multivariate logistic regression.

RESULTS

Adult height was available for 48 patients 8.6 years after GH initiation (IQR, 6.0 to 10.2 years). Height standard deviation score (SDS) increased from -2.9 (IQR, -4.4 to -1.6) at baseline to -1.7 (IQR, -3.9 to -0.1) in adulthood (P < 0.001). Median adult height was below target height [SDS, -0.2 (IQR, -1.4 to 0.4); P < 0.001]. Corrected adult height SDS was -1.3 (IQR, -3.0 to -0.2). Growth outcome was favorable in 24 (52.2%) patients. Significant independent determinants of growth outcome were age at GH initiation [adjusted odds ratio (aOR), 0.68 per additional year; 95% confidence interval (CI), 0.47 to 0.99], height at GH initiation (aOR, 2.6 per additional SDS; 95% CI, 1.15 to 5.9), and mean C-reactive protein levels during follow up (aOR, 0.51 per additional 10 mg/L; 95% CI, 0.28 to 0.92).

CONCLUSION

Long-term GH treatment significantly increased growth in patients with JIA but did not fully restore the genetic growth potential. The response showed marked interindividual variability and was weaker in patients with severe inflammation.

Inflammatory Diseases and Growth: Effects on the GH-IGF Axis and on Growth Plate

This review briefly describes the most common chronic inflammatory diseases in childhood, such as cystic fibrosis (CF), inflammatory bowel diseases (IBDs), juvenile idiopathic arthritis (JIA), and intrauterine growth restriction (IUGR) that can be considered, as such, for the changes reported in the placenta and cord blood of these subjects. Changes in growth hormone (GH) secretion, GH resistance, and changes in the insulin-like growth factor (IGF) system are described mainly in relationship with the increase in nuclear factor-κB (NF-κB) and pro-inflammatory cytokines. Changes in the growth plate are also reported as well as a potential role for microRNAs (miRNAs) and thus epigenetic changes in chronic inflammation. Many mechanisms leading to growth failure are currently known; however, it is clear that further research in the field is still warranted.

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.

Growth abnormalities in children and adolescents with juvenile idiopathic arthritis

In patients with juvenile idiopathic arthritis (JIA) growth impairment and variance in body composition are well-known long-term complications. In the active phases of the disease, particular patients with systemic and polyarticular JIA reveal growth impairment. Some experience "catch-up" growth following reduction in disease activity and lower glucocorticoid doses. Although new therapeutic options are available, there are still 10-20 % of patients with severe forms of the disease who show continuous growth disturbance. Only few studies have specifically addressed body composition in JIA. Bone mass deficits in part could be related to the deficits of muscle mass. Study data on growth hormone treatment in short children with JIA are promising in respect of growth development, final height and body composition. The major goal for physicians is optimal disease control while maintaining normal growth and body composition. Early recognition of patients who develop prolonged growth and body composition disturbances is important as these abnormalities contribute to long-term morbidity and need to be addressed both diagnostically and therapeutically.

Involvement of genes related to inflammation and cell cycle in idiopathic short stature

Idiopathic Short Stature (ISS) defines a condition in which height is <-2SD compared to the mean of a reference population where systemic, endocrinological, nutritional or chromosomal disorders have not been identified and diagnosis is based on exclusion of any known causes of short stature. JAK/STAT pathway is triggered by GH binding to the GH receptor and promotes cellular growth through transcription of GH-responsive genes. In order to identify "candidate genes" differently expressed in ISS subjects with respect to control ones, we analyzed the expression of 84 genes related to JAK/STAT pathway by RT(2) Profiler PCR array approach in a total of 10 subjects. Then, we validated the observed data by Real Time PCR and ELISA assays in a major number of subjects. We found two genes that were differently expressed in ISS subjects with respect to the control group: CXCL9 and FCGR1A/CD64, both significantly up-regulated (fold change 2.17 and 1.70, respectively) and belonging to family of IFN-γ-inducible factors. Further, ISS subjects showed an increased gene expression of IFN-γ and IFI16, higher serum levels of IFN-γ but similar levels of CXCL9 when compared to healthy subjects. In addition, we showed a pubertal modulation of CXCL9 levels. These data suggest that inflammatory and regulatory factors of the cell cycle may be involved in the ISS condition, introducing a new perspective to its etiology.

Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) encompasses a complex group of disorders with arthritis as a common feature. This article provides the pediatrician with a review of the epidemiology, classification, clinical manifestations, and complications of JIA. It also provides an update on the current understanding of the cause of JIA and recent developments in management and a recent review of the long-term outcome in JIA.

Children with oligoarticular juvenile idiopathic arthritis are at considerable risk for growth retardation

OBJECTIVE

To assess linear growth in patients with persistent oligoarticular juvenile idiopathic arthritis (JIA) treated by intra-articular corticosteroid injections (IACSI).

STUDY DESIGN

Data were obtained from a retrospective review of the charts of 95 patients with persistent oligoarticular JIA (69 females). The mean age at first visit was 4.9 ± 3.4 years, with follow-up of 6 ± 3.7 years. The height SDS for chronologic age (z-score) was correlated with the clinical course of the disease and compared among patients treated by IACSI alone (group I) or by a combination of disease-modifying antirheumatic drugs (DMARDs) (group II).

RESULTS

Growth retardation was found in 35.8% of patients (Δ z-score <-0.3), including 11.6% with severe growth retardation (Δ z-score <-1.0). Growth retardation was found in a smaller proportion of patients in group I (any growth retardation, 30.6%; severe growth retardation, 6.5%) than in patients in group II (any growth retardation, 44.4%; severe growth retardation, 21.2%; P < .05). Elevated erythrocyte sedimentation rate values (≥ 40 mm/1sth) indicated a significantly higher risk for growth retardation. All other clinical variables had no association with growth retardation.

CONCLUSION

A significant proportion of patients with persistent oligoarticular JIA have growth retardation and a minority have severe growth retardation. Only elevated erythrocyte sedimentation rate values were proven to be a good predictor of risk for growth retardation.

Omega-3 fatty acids in juvenile idiopathic arthritis: effect on cytokines (IL-1 and TNF-α), disease activity and response criteria

This study aims to demonstrate the effect of omega-3 fatty acids (ω-3 FAs) supplements on the clinical manifestations, laboratory investigations, disease activity, functional capacity, response criteria as well as interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) levels in juvenile idiopathic arthritis (JIA) patients. Twenty-seven JIA patients were included in this study. Dietary supplements of ω-3 FAs 2 g/day were given for 12 weeks. Juvenile arthritis disease activity score in 27 joints (JADAS-27) and pediatric American College of Rheumatology (ACR) response criteria were determined. Childhood Health Assessment Questionnaire (CHAQ) was used to measure the functional status. Assessment of serum IL-1 and TNF-α level was performed using enzyme-linked immunosorbent assay. The mean age of the patients was 12.78 ± 3.26 years, the disease duration was 5.93 ± 3.06 years, and the age at disease onset was 6.78 ± 3.26 years. The TNF-α and IL-1 were significantly higher in the JIA patients compared to the control. There was a significant improvement of active joint count, number of swollen joints, JADAS-27, CHAQ, TNF-α, and IL-1 levels. The pediatric ACR response criteria improved in 92.59% of the patients. The daily requirements of nonsteroidal anti-inflammatory drugs (NSAIDs) obviously decreased. ω-3 FAs supplements reduce the inflammatory response and improve the clinical manifestation in JIA patient. The daily intake of NSAID dose decreased thus reducing the risk of related side effects. Our results support the use of omega-3 fatty acids as an add-on therapy to conventional treatment of JIA.

A preliminary trial of the effect of recombinant human growth hormone on short-term linear growth and glucose homeostasis in children with Crohn's disease

BACKGROUND

It is unclear whether recombinant human growth hormone (rhGH) improves linear growth in children with Crohn's disease (CD).

AIMS

To investigate the effects of rhGH on height velocity (HV) and glucose homeostasis over a 6-month period.

DESIGN AND SETTING

Randomized controlled trial in two tertiary children's hospitals in 22 children with inflammatory bowel disease amongst whom 21 had CD. Duration of disease from diagnosis and number of acute relapses requiring either exclusive enteral nutrition or therapeutic dose of oral prednisolone were similar in the treatment and control groups.

INTERVENTION

Either rhGH (0·067 mg/kg per day) as daily subcutaneous injections (rhGH group; n, 11) or no rhGH, (Ctrl; n, 11) for 6 months.

MAIN OUTCOME MEASURE

Percentage change in HV after 6 months in the two groups. Auxology, puberty, skeletal age, disease factors, treatment and glucose homeostasis were also assessed.

RESULTS

Median HV increased from 4·5 (range, 0·6, 8·9) at baseline to 10·8 (6·1, 15·0) cm/year at 6 month (P = 0·003) in the rhGH group, whereas in the Ctrl group, it was 3·8 (1·4, 6·7) and 3·5 cm/year (2·0, 9·6), respectively (P = 0·58). Median percentage increase in HV after 6 months in the rhGH group was 140% (16·7, 916·7) compared with 17·4% (-42·1%, 97·7%) in the Ctrl group (P < 0·001). There were no significant differences in disease activity and proinflammatory cytokines at baseline and 6 months in both groups and change in bone age for chronological age was also similar in the two groups. In the rhGH group, fasting insulin increased from 4·0 (2·0, 11·0) to 7·0 mU/l (2·0, 16·0) (P = 0·02), whereas in the Ctrl group, it was 3·0 (1·2, 12·7) and 3·8 mU/l (2·1, 7·0) (P = 0·72), respectively.

CONCLUSIONS

Although this pilot trial shows that rhGH can improve short-term linear growth in children with CD, the clinical efficacy of this therapy needs to be further studied in longer-term studies of growth, glucose homeostasis and disease status.

Insulin-like growth factor-binding protein-3 (IGFBP-3) blocks the effects of asthma by negatively regulating NF-κB signaling through IGFBP-3R-mediated activation of caspases

Insulin-like growth factor-binding protein-3 (IGFBP-3) is a multifunctional protein known for modulating mitogenic and metabolic actions of IGFs as well as exerting a variety of biological actions not involving IGFs. Here, we show that IGFBP-3 blocks specific physiological consequences of asthma in an IGF-independent manner in vitro and in vivo. IGFBP-3 treatment effectively reduced all physiological manifestations of asthma examined in vivo (airway hyper-responsiveness, cellular and pathological changes in bronchoalveolar lavage fluid and lung tissue, and expression of numerous proinflammatory molecules). These unique IGFBP-3 effects were further confirmed in IGFBP-3-transgenic mice, thus strengthening the notion of IGFBP-3 actions within the respiratory system. Using human epithelial cells, we demonstrated the following: 1) IGFBP-3 blocks TNF-α-induced expression of proinflammatory molecules; 2) IGFBP-3 attenuates the TNF-α-induced migratory response of eosinophils; and 3) IGFBP-3 negatively regulates TNF-α-induced expression of the key NF-κB regulatory molecules IκBα and p65-NF-κB at the post-translational level. We identified that IGFBP-3 degrades IκBα and p65-NF-κB proteins through IGFBP-3 receptor (IGFBP-3R)-mediated activation of caspases thereby inhibiting TNF-α-induced activation of NF-κB signaling cascades. This unique IGFBP-3/IGFBP-3R action was further confirmed by demonstrating complete inhibition of IGFBP-3 action in the presence of caspase inhibitors as well as IGFBP-3R siRNAs. Non-IGF-binding IGFBP-3 mutants further proved the IGF-independent action of IGFBP-3. Our findings indicate that IGFBP-3 inhibits airway inflammation and hyper-responsiveness via an IGF-independent mechanism that involves activation of IGFBP-3R signaling and cross-talk with NF-κB signaling. The IGFBP-3/IGFBP-3R system therefore plays a pivotal role in the pathogenesis of asthma and can serve as a newly identified potential therapeutic target for this debilitating disease.