Growth hormone treatment in children with rheumatic disease, corticosteroid induced growth retardation, and osteopenia

Chronic inflammation and the growth hormone/insulin-like growth factor-1 axis

Interactions between growth hormone (GH), insulin-like growth factor-1 (IGF-1), and the immune system are complex, bidirectional, but not fully explained. Current reviews based on numerous studies have indicated that chronic inflammation could suppress the GH/IGF-1 axis via several mechanisms such as relative GH and/or IGF-1 insufficiency, peripheral resistance to GH and/or IGF-1 resulting from down-regulation of GH and IGF-1 receptors, disruption in the GH/IGF-1 signalling pathways, dysregulation of IGF binding proteins (IGFBPs), reduced IGF bioavailability, and modified gene regulation due to changes in the microRNA system. It is well-known that relationships between the immune system and the GH/IGF-1 axis are mutual and GH as well as IGF-1 could modulate inflammatory response and the activity of systemic inflammation. Available data indicate that the GH/IGF-1 axis exerts both pro-inflammatory and anti-inflammatory effects. Pro-inflammatory cytokines such as interleukin-6 (IL-6), tumour necrosis factor-a (TNF-α), and interleukin-1b (IL-b) are some of the most significant factors, besides malnutrition, chronic stress, and prolonged use of glucocorticoids, which impair the activity of the GH/IGF-1 axis, and consequently lead to growth retardation in children suffering from childhood-onset chronic inflammatory diseases. In this review, we discuss the mechanisms underlying the impact of chronic inflammation on the GH/IGF-1 axis and growth processes during childhood and adolescence, based on a number of experimental and human studies.

Biological basis of bone strength: anatomy, physiology and measurement

Understanding how bones are innately designed, robustly developed and delicately maintained through intricate anatomical features and physiological processes across the lifespan is vital to inform our assessment of normal bone health, and essential to aid our interpretation of adverse clinical outcomes affecting bone through primary or secondary causes. Accordingly this review serves to introduce new researchers and clinicians engaging with bone and mineral metabolism, and provide a contemporary update for established researchers or clinicians. Specifically, we describe the mechanical and non-mechanical functions of the skeleton; its multidimensional and hierarchical anatomy (macroscopic, microscopic, organic, inorganic, woven and lamellar features); its cellular and hormonal physiology (deterministic and homeostatic processes that govern and regulate bone); and processes of mechanotransduction, modelling, remodelling and degradation that underpin bone adaptation or maladaptation. In addition, we also explore commonly used methods for measuring bone metabolic activity or material features (imaging or biochemical markers) together with their limitations.

Efficacy and safety of recombinant growth hormone treatment in children with growth retardation related to long-term glucocorticosteroid therapy

OBJECTIVE

To evaluate safety and efficacy of recombinant human growth hormone treatment in children on long-term glucocorticoid therapy.

METHODS

A 5-year prospective open-label study included children on glucocorticoid therapy with either standard deviation score (SDS)<-2 for height for chronological age (CA) if naïve to growth hormone treatment, or annual growth rate≥0 SDS for CA if currently receiving growth hormone.

RESULTS

Ninety-eight patients began treatment, 63 discontinued; 59 were analyzed for safety and 58 for efficacy. There was male predominance (78.0%). Median age was 13.0 years. Median height screening was 136.0cm (range, 95.1-159.7cm). Mean SDS for height for CA in the efficacy analysis set was -2.91±1.19 (range, -7.49 to -0.96). Mean growth hormone dose was 0.4, 0.4, 0.4 and 0.3mg/kg/week at month 0, M12, M24, and M36, respectively. Primary analysis of change in SDS for height for CA from baseline to M36 showed a significant increase of 0.80±1.03. Twenty patients in the safety analysis set had≥1 treatment-emergent adverse event (TEAE) related to study treatment. Two patients experienced serious treatment-related TEAEs: 1 case of poor compliance, and 1 of mild hyperglycemia, both already observed under growth hormone treatment.

CONCLUSION

This study suggests that growth hormone treatment could be effective in increasing height in children on long-term glucocorticoid treatment with a safety profile comparable to that in approved rhGH treatment indications.

CLINICAL TRIAL REGISTRATION

NCT00163189.

The impact of underlying disease on fracture risk and bone mineral density in children with rheumatic disorders: A review of current literature

Childhood rheumatic diseases are associated with negative impacts on the skeleton, related to both the underlying illness and complications of therapy. The effects of medications like corticosteroids are well recognized, leading to reductions in bone mineral density and bone strength and concomitant increases in bone fragility and fracture risk. The impact of factors directly attributable to the underlying disease is not as well recognized. In this article, we review relevant literature to identify data which can contribute to an understanding of the impact of childhood rheumatic disease on the skeleton. We conclude that childhood rheumatic diseases are associated with reductions in bone mineral density and increased risk of vertebral and non-vertebral fractures. These data are strongest for juvenile arthritis, while conclusions are more limited for other rheumatic illnesses, like juvenile systemic lupus erythematosus or juvenile dermatomyositis, due to small numbers of patients studied. Finally, we make recommendations for areas in need of further research. These include the need for long-term longitudinal studies and for data to be collected in patients who have not been treated with corticosteroids.

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.

Characterization and prevalence of severe primary IGF1 deficiency in a large cohort of French children with short stature

OBJECTIVE

The prevalence of severe primary IGF1 deficiency (IGFD) is unclear. IGFD must be identified promptly as treatment with recombinant human IGF1 (rhIGF1) is now available. Our objective was to characterize and assess the prevalence of severe primary IGFD in a large cohort of patients evaluated for short stature at a pediatric endocrinology unit in France.

DESIGN

Observational study in a prospective cohort.

METHODS

Consecutive patients referred to our unit between 2004 and 2009 for suspected slow statural growth were included. Patients were classified into eight etiological categories. IGFD was defined by height ≤-3 SDS, serum IGF1 levels <2.5th percentile, GH sufficiency, and absence of causes of secondary IGFD.

RESULTS

Out of 2546 patients included, 337 (13.5%) were born small for gestational age and 424 (16.9%) had idiopathic short stature. In these two categories, we identified 30 patients who met our criterion for IGFD (30/2546, 1.2%). In these 30 patients, we assessed the response to IGF1 generation test, time course of IGF1 levels, and efficiency of GH replacement therapy. The results indicated that only four of the 30 children were definite or possible candidates for rhIGF1 replacement therapy.

CONCLUSION

The prevalence of severe primary IGFD defined using the standard criterion for rhIGF1 treatment was 1.2%, and only 0.2% of patients were eligible for rhIGF1 therapy.

Glucocorticoids and the regulation of growth hormone secretion

Glucocorticoids modulate the secretion of growth hormone (GH) by various and competing effects on the hypothalamus and pituitary gland. The final effects of this modulation depend on hormone concentrations and the duration of exposure. The traditional hypothesis is that chronically raised levels of glucocorticoids suppress the secretion of GH. However, a functional impairment of the GH reserve might also be observed in patients with low levels of glucocorticoids, such as those with secondary hypoadrenalism, which is consistent with the model of biphasic dose-dependent effects of glucocorticoids on the somatotropic axis. This Review updates our current understanding of the mechanisms underlying the effects of glucocorticoids on the secretion of GH and the clinical implications of the dual action of glucocorticoids on the GH reserve in humans. This Review will also address the potential diagnostic and therapeutic implications of GH for patients with a deficiency or excess of glucocorticoids.

[hrGH treatment of glucocorticoid-induced short stature in children]

The treatment of systemic diseases with glucocorticoids is often associated with decreased height velocity (HV), and can result in shorter final height. Interactions between adrenal and GH-IGF axis have been described and can occur at hypothalamic-pituitary level or at the regulation of IGF system, including the IGF1R signaling. The clinical state of these patients may be considered as an absolute and/or functional IGF-1 deficiency. Interventions aiming to restore the normal function of GH-IGF axis might reduce the glucocorticoids-induced growth suppression in these children. It has been shown that recombinant human GH (hrGH) induces an increase in HV and a decrease in protein loss in patients with juvenile idiopathic arthritis treated with glucocorticoids. Significant increment in HV was also described after hrGH treatment in children under glucocorticoid therapy due to inflammatory bowel disease or renal transplantation. There is a positive correlation between HV and the dose of hrGH. The results support that the IGF-1 deficiency in these children may be counteract by hrGH therapy. The effect of hrGH is observed only during the treatment period and depends on the replacement strategy, nutritional status and disease control.

The effects of recombinant human growth hormone on linear growth in children with Crohn's disease and short stature

BACKGROUND/AIMS

The efficacy of recombinant human growth hormone (rhGH) in treating the growth failure associated with Crohn's disease (CD) is unclear.

METHODS

Retrospective data analysis at 12 months before (T-12), 6 months before (T-6), at baseline (T+0), 6 months after (T+6) and 12 months after (T+12) rhGH treatment in seven patients with CD (five males).

RESULTS

Median chronological age (CA) and median difference between CA and bone age was 15.9 yr (range, 13.0 to 17.9) and 1.7 yr (-0.7 to 3.3), respectively. Median dose of rhGH at T+0 was 0.23 mg/wk (0.15 to 0.31). Pubertal status remained unchanged in 6/7 patients. Median albumin and C-reactive protein (CRP) were similar at T+0 and T+6. Median height SDS at T+0, T+6 and T+12 was -2.2 (-4.0 to -1.5), -1.9 (-4.1 to -0.8), -1.9 (-4.1 to -0.7), respectively (NS). Median height velocity (HV) SDS at T+0 and T+6 was -2.5 (-4.8 to 1.4) and -0.9 (-5.3 to 3.4), respectively (NS). There was a positive correlation between percentage change in HV SDS at T+6 and dose of rhGH at T+0 (r = 0.8, p = 0.03).

CONCLUSION

Introduction of rhGH therapy was associated with a cessation in the deterioration in linear growth. However, an improvement in height SDS was not observed over the period of the study. Future studies should explore the efficacy of a higher dose of rhGH in CD.

EULAR evidence-based recommendations on the management of systemic glucocorticoid therapy in rheumatic diseases

OBJECTIVE

To develop evidence-based recommendations for the management of systemic glucocorticoid (GC) therapy in rheumatic diseases.

METHODS

The multidisciplinary guideline development group from 11 European countries, Canada and the USA consisted of 15 rheumatologists, 1 internist, 1 rheumatologist-epidemiologist, 1 health professional, 1 patient and 1 research fellow. The Delphi method was used to agree on 10 key propositions related to the safe use of GCs. A systematic literature search of PUBMED, EMBASE, CINAHL, and Cochrane Library was then used to identify the best available research evidence to support each of the 10 propositions. The strength of recommendation was given according to research evidence, clinical expertise and perceived patient preference.

RESULTS

The 10 propositions were generated through three Delphi rounds and included patient education, risk factors, adverse effects, concomitant therapy (ie, non-steroidal anti-inflammatory drugs, gastroprotection and cyclo-oxygenase-2 selective inhibitors, calcium and vitamin D, bisphosphonates) and special safety advice (ie, adrenal insufficiency, pregnancy, growth impairment).

CONCLUSION

Ten key recommendations for the management of systemic GC-therapy were formulated using a combination of systematically retrieved research evidence and expert consensus. There are areas of importance that have little evidence (ie, dosing and tapering strategies, timing, risk factors and monitoring for adverse effects, perioperative GC-replacement) and need further research; therefore also a research agenda was composed.

Late consequences of chronic pediatric illness

There are many challenges in coping with and adapting to life with a chronic disease, and increased survival cannot be assumed to be associated with increased quality of life. A recent systematic review shows there is wide variation in outcomes depending on the definitions and measurements used to estimate the prevalence of chronic health conditions, making the impact of disability on children's health and social functioning difficult to assess; various authors have called for an international consensus about the conceptual definition of chronic health conditions in childhood. It frequently is difficult to determine if problems in psychosocial functioning are caused by the underlying illness, by treatment, or by the resultant effects of either illness or treatment on physical growth or cognitive development. Assessment and treatment of mental health should be an integral component of the comprehensive care of chronically ill children and adolescents. Transition of care is an important process that addresses significant changes from child-oriented to adult-oriented care. Adults who have chronic health conditions should continue to be evaluated periodically for late consequences of the childhood illness and early medical care, and attention should be paid to their ongoing psychosocial, psychiatric, educational, and vocational needs.