Safety of inhaled corticosteroids in children with asthma

Glucocorticoid-induced leucine zipper (GILZ) mediates glucocorticoid action and inhibits inflammatory cytokine-induced COX-2 expression

Cyclooxygenase-2 (COX-2) plays an important role in rheumatoid arthritis and therefore, has been a major target for anti-arthritis therapies. The expression of COX-2 is induced by inflammatory cytokines such as TNF-alpha and IL-1beta, and inhibited by glucocorticoids. However, the molecular mechanisms underlying the anti-inflammatory and immune suppressive actions of glucocorticoids are not well defined. Here we report that glucocorticoid-induced leucine zipper (GILZ) mimics glucocorticoid action and inhibits inflammatory cytokine-induced COX-2 expression in bone marrow mesenchymal stem cells, the cells that have been recently implicated in the pathogenesis and progression of rheumatoid arthritis. Using a retrovirus-mediated gene expression approach we demonstrate that overexpression of GILZ inhibits TNF-alpha and IL-1beta-induced COX-2 mRNA and protein expression, and knockdown of GILZ by shRNA reduces glucocorticoid inhibition of cytokine-induced COX-2 expression. Consistent to these results, overexpression of GILZ also inhibits NF-kappaB-mediated COX-2 promoter activity. Finally, we show that GILZ inhibits COX-2 expression by blocking NF-kappaB nuclear translocation. Our results suggest that GILZ is a key glucocorticoid effect mediator and that GILZ may have therapeutic value for novel anti-inflammation therapies.

Regulation of mesenchymal stem cell osteogenic differentiation by glucocorticoid-induced leucine zipper (GILZ)

Mesenchymal stem cells (MSCs) can differentiate into multiple cell lineages, including osteoblasts and adipocytes. We reported previously that glucocorticoid-induced leucine zipper (GILZ) inhibits peroxisome proliferator-activated receptor gamma-2 (Ppargamma2) expression and blocks adipocyte differentiation. Here we show that overexpression of GILZ in mouse MSCs, but not MC3T3-E1 osteoblasts, increases alkaline phosphatase activity and enhances mineralized bone nodule formation, whereas knockdown of Gilz reduces MSC osteogenic differentiation capacity. Consistent with these observations, real-time reverse transcription-PCR analysis showed that both basal and differentiation-induced transcripts of the lineage commitment gene Runx2/Cbfa1, as well as osteoblast differentiation marker genes including alkaline phosphatase, type I collagen, and osteocalcin, were all increased in GILZ-expressing cells. In contrast, the mRNA levels of adipogenic Ppargamma2 and C/ebpalpha were significantly reduced in GILZ-expressing cells under both osteogenic and adipogenic conditions. Together, our results demonstrate that GILZ functions as a modulator of MSCs and that overexpression of GILZ shifts the balance between osteogenic and adipogenic differentiation of MSCs toward the osteogenic pathway. These data suggest that GILZ may have therapeutic value for stem cell-based therapies of metabolic bone diseases, such as fracture repair.

[Wheezing in infants and toddlers: new insights]

Wheezing in infants and toddlers is a common symptom, and these patients are difficult to approach--both diagnostically and therapeutically. Congenital conditions causing wheezing disorders should not be missed and--not all wheezy bronchitis is or will become asthma. Results from longitudinal studies indicate that the term "asthma" includes different phenotypes: so-called transient early wheezing, non atopic wheezing and atopic wheezing (asthma). Transient early wheezing is generally accepted to define recurrent wheezing in non-atopic babies or toddlers and tends to disappear by the age of 3. The primary risk factor is reduced pulmonary function since birth. The most common cause for non-atopic wheezing is viral infection, most frequently caused by respiratory syncytial virus. Infection with respiratory syncytial virus is a risk factor for ongoing wheeze during childhood but resolves in most children by the age of 13. Asthma can start at any age and is determined by a more chronic condition, provoked by a number of triggers in addition to viruses, frequently associated with a family history of atopy, early allergic sensitization and concomitant atopic dermatitis. Only asthma seems to be a progressive disease; and there is evidence from long-term studies that if anti-inflammatory interventions are started late, it might be too late to alter the natural course of the disease with its decline in pulmonary function. On the other hand, there is no evidence that small children with non-atopic wheezy bronchitis would benefit from long-term therapy with anti-inflammatory treatment; in this group a therapeutic trial with bronchodilators is sufficient. The diagnostic and therapeutic challenges of diagnosing asthma in this age group are considerable and require a comprehensive approach.

Fluticasone and beclometasone: what are their effects on children's growth?

Fear of growth retardation may account for the underuse of inhaled corticosteroids in children with asthma, despite compelling evidence of their effectiveness. This fear may be reduced with newer agents with lower oral bioavailability if their theoretical advantage of fewer systemic adverse effects than the standard treatment of inhaled beclometasone is realized in practice. This review aims to determine if one of the newer agents, inhaled fluticasone, has less effect on the growth of pre-pubertal asthmatic children than inhaled beclometasone. The outcome measure was growth velocity. Two double blind, randomized controlled trials were identified. In one of the studies the mean growth velocity in the fluticasone group was 0.7 cm/year greater than in the beclometasone group. In the second, smaller study the mean growth velocity in the fluticasone group was 0.8 cm/year greater. There is therefore some evidence that fluticasone has less (if any) adverse effect on growth.

Systemic activity of inhaled corticosteroid treatment in asthmatic children: corticotrophin releasing hormone test

BACKGROUND

A study was undertaken to assess the function of the hypothalamic-pituitary-adrenal axis (HPA) in a group of asthmatic children before and after treatment with inhaled corticosteroids.

METHODS

Thirty prepubertal patients of mean (SD) age 6.7 (1.8) years were treated with inhaled corticosteroids. All children underwent a corticotrophin releasing hormone (CRH) test with evaluation of serum cortisol and adrenocorticotrophin hormone (ACTH) levels before and after 3 months of treatment. Twenty four hour urine samples were also collected to measure free cortisol (UFC) excretion.

RESULTS

Subjects showed no difference between basal serum cortisol levels (mean change -18; 95% CI -41 to 5; p=0.118) and delta (peak minus basal) levels (mean change -13; 95% CI -38 to 12; p=0.308) before and after treatment, whereas the peak cortisol level (mean change -31; 95% CI -55 to -7; p=0.013) and area under the curve (AUC) (mean change -175; 95% CI -288 to -63; p=0.003) after CRH were significantly lower following treatment. Basal, peak and AUC ACTH were significantly lower after treatment (p<0.05, p=0.004 and p=0.003, respectively), while delta ACTH was similar before and after treatment ((mean change -12; 95% CI - 31 to -7; p=0.199). No significant reduction in 24 hour UFC was observed after the treatment period (before 14.9 (7.1), after 15.0 (11.6); mean change 0.1, 95% CI -5.2 to 5.4; p=0.967). No correlation was found between UFC and any of the parameters of cortisol excretion following the CRH test, either before or after treatment.

CONCLUSIONS

These data suggest that, at the dosage and for the treatment period used, inhaled steroids do not seem to suppress the HPA axis in the majority of patients. The CRH test may be more sensitive than 24 hour UFC and morning plasma cortisol levels in evaluating systemic activity of inhaled corticosteroid treatment.