Pharmacogenomics of pediatric asthma

Association between beta-2 adrenergic receptor variants and clinical outcomes in children and adolescents with acute asthma

Objective

To investigate whether different genotypes of p.Arg16Gly, p.Gln27Glu, p.Arg19Cys and p.Thr164Ile variants interfere in response to treatment in children and adolescents with moderate to severe acute asthma.

Methods

This sample comprised patients aged 2 to 17 years with a history of at least two wheezing episodes and current moderate to severe asthma exacerbation. All patients received multiple doses of albuterol and ipratropium bromide delivered via pressurized metered-dose inhaler with holding chamber and systemic corticosteroids. Hospital admission was defined as the primary outcome. Secondary outcomes were changes in forced expiratory volume in the first second after 1 hour of treatment, and for outpatients, length of stay in the emergency room. Variants were genotyped by sequencing.

Results

A total of 60 patients were evaluated. Hospital admission rates were significantly higher in carriers of the genotype AA relative to those with genotype AG or GG, within the p.Arg16Gly variant (p=0.03, test χ², alpha=0.05). Secondary outcomes did not differ between genotypes.

Conclusion

Hospital admission rates were significantly higher among carriers of the genotype AA within the p.Arg16Gly variant. Trial registration: ClinicalTrials.gov: NCT01323010

"Omics" in pharmaceutical research: overview, applications, challenges, and future perspectives

In the post-genomic era, biological studies are characterized by the rapid development and wide application of a series of "omics" technologies, including genomics, proteomics, metabolomics, transcriptomics, lipidomics, cytomics, metallomics, ionomics, interactomics, and phenomics. These "omics" are often based on global analyses of biological samples using high through-put analytical approaches and bioinformatics and may provide new insights into biological phenomena. In this paper, the development and advances in these omics made in the past decades are reviewed, especially genomics, transcriptomics, proteomics and metabolomics; the applications of omics technologies in pharmaceutical research are then summarized in the fields of drug target discovery, toxicity evaluation, personalized medicine, and traditional Chinese medicine; and finally, the limitations of omics are discussed, along with the future challenges associated with the multi-omics data processing, dynamics omics analysis, and analytical approaches, as well as amenable solutions and future prospects.

Clinically relevant pharmacogenomic testing in pediatric practice

Clinicians and patients continue to convey interest in personalized medicine. The objective of personalized medicine is to improve healthcare by tailoring disease prevention, diagnosis, and treatment strategies for individuals based on their unique clinical history and genetic composition. This article offers an overview of pharmacogenomics, discusses caveats specific to pharmacogenomics in pediatric populations, provides evidence-based recommendations for pediatric clinicians, and offers insight regarding the future role of pharmacogenomics testing in pediatric medicine. Reviews of the current literature and thoughtful discussions are presented regarding the pharmacogenomics of antidepressants, codeine and oncologic, asthma, and immunomodulatory pharmacotherapies.

Pharmacogenomics and pharmacoepigenomics in pediatric medicine

In the past several years, human genetics studies have progressed from monogenic to complex and common diseases because of the advancement in technologies. There is increased knowledge of the pharmacokinetics and pharmacogenomics of the drugs in adults as well as in children. These technological developments provided new diagnostic, prognostic, and therapeutic opportunities. We are now in a position to address many additional ambitious questions. For instance, in clinical medicine, interindividual variation in drug response is a major problem. Some of the heterogeneity of drug safety and efficacy among individuals can be explained by pharmacogenomics. It has also the potential to improve the treatment in both adults and children. In pediatrics however, there is ontogeny and metabolic capacity in children is different compared to adults. Several specific developmental changes may underlie some of the variability in drug response seen in children. They may also be responsible for adverse drug reactions (ADRs). Therefore, much of the diversity in drug effects cannot be explained by studying the genomic diversity alone. It is necessary to include the effect of growth (involves variations in gene expression) along with genetic differences when explaining the variability in treatment response. In this respect epigenomics may expand the scope of pharmacogenomics towards optimization of drug therapy. Future studies must focus on periods of maturation of the drug-metabolizing enzymes and polymorphisms in their genes by using candidate gene approach, gene expression analysis, genome-wide haplotype mapping, and proteomics. The integration of genetic data and clinical phenotypes along with the role of other factors is necessary to evaluate both efficacy and ADRs of any drug. It may require extensive genetic epidemiological studies spanning over many years.

Variability in laboratory immune parameters is associated with stress hormone receptor polymorphisms

OBJECTIVES

Interpretation of laboratory immune data in healthy human subjects is often challenging due to wide inter-subject variability. Since endocrine and immune mediators have been mutually interlinked, a potential explanation for the significant variability seen in immune data even when controlled for technical variability and demographics is differences in the binding affinity of ligand with hormone receptors on the surface of immune cells, which can be associated with single nucleotide polymorphisms (SNP).

METHODS

We categorized immunoregulatory cellular profiles from PBMC of 207 healthy volunteers according to glucocorticoid receptor (GR: Bcl1, TthIIII, and A3669G) and β₂-adrenergic receptor (β2AR: Gly16Arg and Gln27Glu) polymorphisms. Subjects were genotyped for each SNP, and Th1, Th2, Th1/Th2 ratio, regulatory T cell (T(reg)), Tr1, and Th3 cell numbers were assessed. Immune parameters in the SNP groups were compared to the wild type (WT).

RESULTS

Significant differences were observed in Th2 and the Th1/Th2 ratio for the β2AR SNP Gly16Arg. Th1, the Th1/Th2 ratio, and Tr1 differed significantly by SNP of Gln27Glu. In addition, the effect of age on Th2 and the effect of the body mass index on the Th1/Th2 ratio significantly differed across subtypes of the Gly16Arg SNP. Significant differences based on allergic status and gender were also seen for T(reg), Th1, and Th2 across Gly16Arg, Gln27Glu, and TthIIII SNP.

CONCLUSIONS

These data suggest that SNP from various components of the stress-immune network may be useful for subgrouping of immune responses to more accurately categorize psychoneuroimmunological components of stress risk in individual subjects. This approach may have significant research and clinical potential.

Differential expression of the β2-adrenoreceptor and M3-cholinoreceptor genes in bronchial mucosa of patients with asthma and chronic obstructive pulmonary disease

BACKGROUND

Bronchodilators are drugs of choice in the combined therapy of bronchial asthma and chronic obstructive pulmonary disease (COPD). However, the therapeutic sensitivity is variable between patients, probably because of structural features of regulating molecules or variation in key genes' expression.

OBJECTIVES

The aim of this study was to evaluate the β2-adrenoceptor (ADRB2) and M3-cholinoreceptor (CHRM3) gene expression in bronchial mucosa in patients with COPD and different severity of asthma.

METHODS

Biopsy specimens of right middle lobar bronchus were obtained from 59 asthma patients (10 patients with severe brittle phenotype, 14 patients with severe asthma with persistent airflow limitation, 27 patients with moderate asthma, and 8 patients with mild asthma) and 10 COPD patients with or without bronchial hyperresponsiveness (BHR). The messenger RNA (mRNA) levels for the ADRB2 and CHRM3 genes in bronchial mucosa were revealed using quantitative reverse transcription polymerase chain reaction (RT-PCR) and compared between groups.

RESULTS

An increase of the ADRB2 genes expression was demonstrated in patients with severe asthma and COPD as compared with patients with mild and moderate disease. Significantly higher levels of ADRB2 mRNA were observed in patients with severe asthma with persistent airflow limitation. Significantly lower levels of the CHRM3 mRNA were observed in patients with COPD as compared with asthma patients. Also, CHRM3 gene expression was significantly elevated in COPD patients with BHR as compared with patients without BHR.

CONCLUSIONS

The results of the study suggest that the differential expression of the ADRB2 and CHRM3 genes is associated with asthma and COPD clinical subtypes.