Paediatric asthma control under a community management model in China: a protocol for a prospective multicentre cohort study.

INTRODUCTION: Childhood asthma is globally one of the most common respiratory disorders and accounts for more school absences and more hospitalizations than any other chronic illness. The worldwide economic burden of this disease exceeds those of HIV/AIDS and tuberculosis combined. Proper intervention and effective management is of paramount importance for the control and prognosis of paediatric asthma. Unfortunately, the rate of uncontrolled and partially controlled paediatric asthma in China is >90%. This study will use a new management model to investigate the status of asthma control and the adherence of patients to a medication protocol. METHODS: This prospective, multicentre, observational study will be conducted at 15 hospitals on children (n=800) diagnosed with asthma. Each patient will be assigned to either the nearest community hospital or Shanghai Children's Medical Center, whichever is closer to the patient's home, according to the decision of parents. Participants were divided into two groups: tertiary care hospital (Shanghai Children's Medical Center) follow-up group and community hospital follow-up group. The primary outcome will be the difference in the proportion of controlled, partially controlled and uncontrolled asthma among the two groups. Secondary outcomes will be the differences in adherence rate, lung function, exacerbations, growth development, total asthma-related unscheduled visits, days absent from school and loss of working days for the patient's caregiver. Data will be analysed on an intention-to-treat and a per-protocol basis. ETHICS AND DISSEMINATION: Ethics approval was obtained from the Institutional Review Board of Shanghai Children's Medical Center affiliated with Shanghai Jiao Tong University of Medicine. We plan to publish the results of this study in a peer-reviewed journal article.

Comparison of the crystal structure and function to wild-type and His25Ala mutant human heme oxygenase-1.

Human heme oxygenase-1 (hHO-1) is a rate-limiting enzyme in heme metabolism. It regulates serum bilirubin level. Site-directed mutagenesis studies indicate that the proximal residue histidine 25 (His25) plays a key role in hHO-1 activity. A highly purified hHO-1 His25Ala mutant was generated and crystallized with a new expression system. The crystal structure of the mutant was determined by X-ray diffraction technology and molecular replacement at the resolution of 2.8 A, and the model of hHO-1 His25Ala mutant was refined. The final crystallographic and free R factors were 0.245 and 0.283, respectively. The standard bond length deviation was 0.007 A, and the standard bond angle deviation was 1.3 degrees . The mutation of His25 to Ala led to an empty pocket underneath the ferric ion in the heme, leading to loss of binding iron ligand. Although this did not cause an overall structural change, the enzymatic activity of the mutant hHO-1 was reduced by 90%. By supplementing imidazole, the HO-1 activity was restored approximately 90% to its normal level. These data suggest that Ala25 remains unchanged in the structure compared to His25, but the important catalytic function of hHO-1 is lost. Thus, it appears that His25 is a crucial residue for proper hHO-1 catalysis.

Heme oxygenase-1 attenuates ovalbumin-induced airway inflammation by up-regulation of foxp3 T-regulatory cells, interleukin-10, and membrane-bound transforming growth factor- 1.

Cumulative evidence suggests the up-regulation of interleukin (IL)-10 and T-regulatory (Treg) cells is implicated in anti-inflammatory effect of heme oxygenase-1 (HO-1). Thus, we postulated that induction of HO-1 could augment IL-10 and transforming growth factor (TGF)-beta production and foxp3+CD4+CD25+ Treg cell function, thereby leading to attenuation of airway inflammation. In this study, CD4+CD25+ Treg cells isolated from mouse spleen were either transfected with a HO-1 expression vector (pcDNA3HO-1) or treated with a HO-1 inducer (hemin). Up-regulation of HO-1 enhanced foxp3 expression and IL-10 secretion in the Treg cells in vitro. Next, BALB/c, C57/B6.129, and IL-10-deficient B6.129P2-Il10tm1Cgn/J mice were challenged by ovalbumin to induce airway inflammation. Consistent with in vitro findings, hemin treatment resulted in induction of HO-1 and foxp3 and production of IL-10 and membrane-bound TGF-beta1 in vivo. This was further correlated with decrease of ovalbumin-specific immunoglobulin E level and eosinophil infiltration in bronchial alveolar lavage fluid from the asthmatic mice. Furthermore, hemin significantly enhanced the biological activity of CD4+CD25+ Treg cells. This protective effect was specifically blocked by Sn-protoporphyrin, a HO-1 enzymatic inhibitor. Finally, hemin failed to up-regulate the function of CD4+CD25+ Treg cells from IL-10-deficient mice. Our study indicates that HO-1 exerts its protective effect on asthma through a mechanism mediated by foxp3+CD4+CD25+ Treg cells, IL-10, and membrane-bound TGF-beta1.

Reduction of bilirubin by targeting human heme oxygenase-1 through siRNA.

Neonatal hyperbilirubinemia is a common clinical condition caused mainly by the increased production and decreased excretion of bilirubin. Current treatment is aimed at reducing the serum levels of bilirubin. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that generates bilirubin. In this study we intended to suppress HO-1 using the RNA interference technique. Small interfering RNA (siRNA)-A, -B, and -C were designed based on human HO-1 (hHO-1) mRNA sequences. siRNA was transfected into a human hepatic cell line (HL-7702). hHO-1 transcription and protein levels were then determined. In addition, the inhibitory effect of siRNA on hHO-1 was assessed in cells treated with hemin or transfected with an hHO-1 plasmid. siRNA-C showed the most potent suppressive effect on hHO-1. This inhibition is dose and time dependent. Compared with control, both hemin and hHO-1 plasmids up-regulated hHO-1 expression in HL-7702 cells. However, the up-regulation was significantly attenuated by siRNA-C. Furthermore, the decrease in hHO-1 activity was coincident with the suppression of its transcription. Finally, siRNA-C was shown to reduce hHO-1 enzymatic activity and bilirubin levels. Thus, this study provides a novel therapeutic rationale by blocking bilirubin formation via siRNA for preventing and treating neonatal hyperbilirubinemia and bilirubin encephalopathy at an early clinical stage.

Heme oxygenase-1-mediated CD4+CD25high regulatory T cells suppress allergic airway inflammation.

Heme oxygenase-1 (HO-1) has anti-inflammatory effects in asthma. CD4+CD25(high) regulatory T cells (Treg) are a potent immunoregulator that suppresses the immune response. We studied the effects of HO-1-mediated CD4+CD25(high) Treg on suppression of allergic airway inflammation by comparing mice treated with hemin, OVA, Sn-protoporphyrin (SnPP), and hemin plus SnPP. Airway responsiveness, airway eosinophil infiltration, the level of OVA-specific IgE, and the numbers of cells in general and eosinophils in particular in bronchial alveolar lavage fluid were lower in the hemin group than in the OVA, SnPP, and hemin plus SnPP groups. The expressions of HO-1 mRNA and protein in the lung were increased by repeated administrations of hemin and SnPP. However, the activity of HO-1 was highest in hemin mice. The percentage and suppressive function of CD4+CD25(high) Treg and the expression of Foxp3 mRNA were obviously enhanced after treatment with hemin. This increase was diminished by the administration of SnPP. The concentration of serum IL-10 was higher in the hemin group than in the other groups, whereas the level of serum TGF-beta did not significantly differ across groups. Furthermore, the ratio of IFN-gamma/IL-4 mRNA in the lung was higher in hemin-treated mice than in OVA and SnPP mice. The suppressive capacity of CD4+CD25(high) Treg was not enhanced in the IL-10-deficient mice treated with hemin. In conclusion, our experiments in the animal model demonstrated that HO-1 has anti-inflammatory effects, probably via enhancement of the secretion of IL-10 and promotion of the percentage of CD4+CD25(high) Treg.

[Clinical study on effect of chuankezhi injection in treating children with bronchial asthma].

OBJECTIVE: To evaluate the efficacy and safety of chuankezhi injection to children with bronchial asthma. METHODS: Sixty-eight children suffered from asthma and/or asthma complicated with allergic rhinitis were randomly divided into the treated group and the control group, who received treatment of chuankezhi injection and Ginkgo injection respectively. Clinical observation on daily-symptom scores, and lung functions as peak expiratory flow (PEF), and forced expiratory volume in one second (FEV1) were conducted. RESULTS: After treatment the median of symptomatic scores in the treated group was 6.0 (M25-M75: 4.9-21.5) and that in the control group was 10.0 (M25-M75: 6.19-27.5), showing significant difference between groups; significant improvement was shown in the treated group, in which the PEF variance rate was reduced to 4.3 +/- 5.1%, while in the control group, it was 5.9 +/- 6.7%, the difference between the two groups was significant. Similar result also showed in comparison of FEV1 rate. CONCLUSION: Chuankezhi is helpful in improving clinical symptoms, reducing PEF variance rate and enhancing lung function in children with bronchial asthma, so as to be benefit to the long-term stable alleviation of asthma.