Sodium cromoglycate in asthma: correlation between response and serum concentrations

Intermediary quantitative traits--an alternative in the identification of disease genes in asthma?

Intermediary quantitative traits are a possible alternative for the identification of disease genes. This may be particularly relevant when diagnostic criteria are not very well defined as described for asthma. We analyzed serum samples from 944 individuals of 218 asthma families for 17 cytokines (eotaxin, GM-CSF, IFNγ, IL1B, IL1RA, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12(p40), IL-13, IL-17, IL-23, IL-33, TSLP and TNF-α) and determined the heritability. Linked chromosomal regions were identified by a genome-wide analysis using 334 autosomal microsatellite marker and association tested by further 550 SNP marker at genes implicated earlier with immune response. Heritability varied with TNF-α and IL-8 levels having the highest and TSLP having the lowest heritability. Linkage was significantly increased only for IL-12(p40) at D17S949. There were multiple significant single-nucleotide polymorphisms (SNP) associations (P<0.05) as found in the transmission disequilibrium test, whereas only a few replicated in parents or children only. These include SNPs in IL1RN that were associated with IL-33 and TSLP levels, and a SNP in NR3C2 that was associated with eotaxin, IL-13 and IFN-γ levels. Circulating level of serum cytokines exhibits genetic associations with asthma traits that are otherwise not detected using clinical diagnosis or when the clinical details are ambiguous.

Disodium cromoglycate use in children and adolescents with asthma: correlation between plasma concentrations and protective effects for various inhalation methods

BACKGROUND

Few studies have addressed the association between the plasma concentration of disodium cromoglycate and its protective effects on patients with bronchial asthma.

OBJECTIVE

We measured plasma concentrations of disodium cromoglycate for various asthmatic treatments in children and adolescents and estimated plasma concentrations and protective effects.

METHOD

Disodium cromoglycate as a 2-mg aerosol (n = 12), 4-mg aerosol (n = 5), or 20-mg nebulizer solution (n = 13) was inhaled by patients in remission.

RESULTS

The plasma concentrations of disodium cromoglycate after 5 minutes of inhalation were 3.04 +/- 2.72 ng/mL in the 2-mg aerosol group, 2.95 +/- 0.86 ng/mL in the 4-mg aerosol group, and 7.72 +/- 4.65 ng/mL in the nebulizer solution group. Subjects who used the nebulizer exhibited markedly higher plasma concentrations of disodium cromoglycate. There was a significant correlation between the concentration of disodium cromoglycate at 5 minutes and the protective effect determined by a ratio of the difference in the asthma score between baseline and treatment periods to the baseline asthma score.

CONCLUSION

When the plasma concentration of disodium cromoglycate is low, administration of larger aerosol dose or nebulization might be necessary.

Plasma concentrations of disodium cromoglycate after various inhalation methods in healthy subjects

AIMS

To compare the plasma concentrations of disodium cromoglycate (DSCG) following various inhalation procedures in healthy volunteers.

METHODS

Nine healthy subjects inhaled 2 mg of aerosol, 20 mg of nebuliser solution only, 20 mg of nebuliser solution mixed with isotonic saline, or 20 mg of nebuliser solution mixed with saline and procaterol, a beta2-adenoceptor agonist, on separate occasions 2-3 weeks apart. Plasma concentrations of DSCG were determined by high-performance liquid chromatography (h.p.l.c.).

RESULTS

The peak plasma concentrations of DSCG were 1.5+/-0.7 (range 0.4-2.4) ng ml-1 in the aerosol group, 8.8+/-6.2 (range 5.3-19.9) ng ml-1 in the nebuliser solution only group, 17.2+/-16.3 (range 5.0-38.6) ng ml-1 in the nebuliser solution plus isotonic saline group, and 24.5+/-11. 9 (range 10.2-44.9) ng ml-1 in the nebuliser solution plus saline and procaterol group. Thus subjects who used the nebuliser had markedly higher plasma concentrations of DSCG than subjects who used the aerosol inhaler.

CONCLUSIONS

These findings may have important implications for the evaluation of inhalation treatment with DSCG for bronchial asthma.

Theophylline attenuation of airway responses to allergen: comparison with cromolyn metered-dose inhaler

BACKGROUND

The purpose of this study was to compare the protection afforded by individualized doses of theophylline and a cromolyn metered-dose inhaler (MDI) during allergen challenge.

METHODS

The study design was randomized, double-blind, and crossover. Responses to inhaled allergen were measured in 16 subjects with allergic asthma (age range, 18 to 35 years) after 7 days of treatment with either placebo, once daily slow-release theophylline producing a mean +/- SD serum concentration of 16 +/- 5 micrograms/ml during the late phase, or 2 mg of cromolyn administered by MDI four times daily. Forced expiratory volume in 1 second was measured at frequent intervals, and airway responsiveness to histamine was measured before and 3 hours after allergen challenge.

RESULTS

The mean +/- SD maximum decrease in forced expiratory volume in 1 second during the late phase was 30% +/- 14% during placebo treatment, 16% +/- 13% during theophylline treatment, and 13% +/- 14% during cromolyn treatment (placebo vs theophylline and cromolyn, p = 0.0001; theophylline vs cromolyn, p = 0.1). The geometric mean fold increase in airway responsiveness was 3.0 +/- 1.7 during placebo treatment, 1.7 +/- 1.7 during theophylline treatment, and 1.5 +/- 1.6 during cromolyn treatment (placebo vs theophylline and cromolyn, p = 0.0001; theophylline vs cromolyn, p = 0.1).

CONCLUSIONS

Theophylline, when administered once daily as a slow-release formulation, was as effective as cromolyn, administered four times daily through an MDI, in attenuating airway responses to inhaled allergen. The protection afforded by both treatments, however, was modest when compared with the results of similar studies with inhaled corticosteroids or other cromolyn formulations that deliver more drug to the lungs than the MDI available in the United States.

Reflections on the mechanism(s) of action of sodium cromoglycate (Intal) and the role of mast cells in asthma

In this review, only a few questions concerning the mechanism(s) of action of sodium cromoglycate in asthma have been considered. The large number of cells and mediator pathways where sodium cromoglycate may have pharmacological effects are depicted. In addition to its mast cell effect, sodium cromoglycate is also inhibitory to macrophages, eosinophils, monocytes and platelets, which are all important components in the inflammatory response of asthma. From studies with bradykinin and sulphur dioxide it is also known that the drug can block afferent discharges along non-myelinated nerves. Although the ability of sodium cromoglycate to block late phase responses and acquired hyper-reactivity is not questioned, to what extent its therapeutic efficacy can be accounted for by actions on these leukocytes and reflex pathways is not known. When administered to patients with asthma, sodium cromoglycate results in symptomatic improvement, but there is still much to be learned about its mode of action.