The Changes Of VEGF And TGF-β₁ In The Serum Of Children With Asthma And Its Clinical Significance

Objective:Bronchial asthma is a global common respiratory diseases and it is the most common chronic airway disease in childhood.Its prevalence is increasing year by year in the world.It represents a significant social and economic burden. Bronchial asthma is a chronic disease of the airways, which is characterized by persistent airway inflammation, airway hyperresponsiveness(AHR) and reversible airways obstruction. Chronic persistent airway hyperresponsiveness and inflammatory stimulation may reflect airway remodeling. This airway remodelling is an irreversible changes in the structure of the airway wall,including shedding of the epithelium, goblet cell hyperplasia, increased blood vessel number and area, deposition of extracellular matrix (ECM) and Hyperplasia and hypertrophy of airway smooth muscle cells (ASMC). However, the pathogenesis of bronchial asthma has not been determined. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogenic peptide and plays a key role in vasculogenesis, which is a mediator of airway inflammation and remodelling in bronchial asthma. Transforming growth factor-β1 (TGF-β1) is a multifunctional cytokine and plays important roles in diverse biological processes of bronchial asthma.But there are few studies elucidating the interactions between VEGF and TGF-β1 in bronchial asthma. In this study,we detect the levels of VEGF and TGF-β1 in the serum of children with asthma to investigate the correlations and their roles in the pathogenesis of bronchial asthma.Methods:All the 117 subjects aged 6 months-8 years old in case group were from out-patient clinic in pediatrics or Pediatric Medical wards of our hospital from june,2009 to February,2010,which were divided into pneumonia group (35 subjects),bronchiolitis group (32 subjects),asthma groupⅠ(24 subjects) and asthma groupⅡ(26 subjects). Normal controls were 18 subjects.Some of them were from Pediatic Surgery wards, who were not suffering from respiratory diseases,and the others were from Children's preventive health care section to do health check-up. All normal controls had no family history of asthma, no personal and family history of allergic diseases and no recent history of infection.And they were not receiving corticosteroids and leukotriene antagonists for 2 months. All the patients of pneumonia group,bronchiolitis group and asthma group were diagnosed according to the seventh edition of Pediatrics.The cases of asthma groupⅠwere wheezhing episodes≤3 times and the cases of asthma groupⅡwere wheezhing episodes＞3 times.The patients of bronchiolitis and asthma group were treated with budesonide inhalation therapy.Patients aged＜3 years old inhaled budesonide 0.5mg each time twice a day for 7 days and the others aged≥3 years old inhaled 1.0mg each time.The levels of VEGF and TGF-β1 were detected respectively by sandwich ELISA procedures.All of the data was analyzed using statistical method.Results:The levels of serum VEGF in normal control group were basic expression. The levels of serum VEGF in pneumonia group and in bronchiolitis group slightly increased and increased,respectively,but with no statistical significance. (t=0.16,0.46,P＞0.05, P＞0.05). The levels of serum VEGF were distinct higher in asthma groupⅠthan those in normal controls and the levels in asthma groupⅡwere much higher with statistical significance (t=2.07,3.66,P＜0.05,P＜0.01).The difference between pneumonia group and bronchiolitis group did not have statistical significance. (t=0.38,P＞0.05). The levels of serum VEGF in pneumonia group compared with those in asthma groupⅠand asthma groupⅡwere statistical different (t=2.32,3.84,P＜0.05,P＜0.01). The levels of serum VEGF in bronchiolitis group compared with those in asthma groupⅠand asthma groupⅡwere statistical different (t=2.18,3.57,P＜0.05,P＜0.01).There was no statistical difference between the serum VEGF levels in asthma groupⅠand asthma groupⅡ(t=1.45, P＞0.05).After 7 days budesonide inhalation therapy, the levels of serum VEGF in pneumonia group were slightly lower,and in bronchiolitis group were lower than 7 days ago but both of them were with no statistical significance (t=0.10,0.65,P＞0.05,P＞0.05).The serum VEGF levels in asthma groupⅠdistinct lower than those of 7 days ago (t=2.05,P＜0.05),whereas the serum VEGF levels in asthma groupⅡslightly decreased after treatment and with no statistical significance (t=0.67,P＞0.05)The levels of serum TGF-β1 in normal control group were basic expression. The levels of serum TGF-β1 in pneumonia group and in bronchiolitis group slightly increased but with no statistical significance (t=0.84,0.94,P＞0.05, P＞0.05). The levels of serum TGF-β1 were distinct higher in asthma groupⅠthan those in normal controls and the levels in asthma groupⅡwere much higher with statistical significance (t=2.62,3.87,P＜0.05,P＜0.01).The difference between pneumonia group and bronchiolitis group did not have statistical significance (t=0.24,P＞0.05). The levels of serum TGF-β1 in pneumonia group compared with those in asthma groupⅠand asthma groupⅡwere statistical different (t=2.47,3.70,P＜0.05,P＜0.01). The levels of serum TGF-β1 in bronchiolitis group compared with those in asthma groupⅠand asthma groupⅡwere statistical different (t=2.06,3.36,P＜0.05, P＜0.01).There was no statistical difference between the serum TGF-β1 levels in asthma groupⅠand asthma groupⅡ(t=1.42, P＞0.05).After 7 days budesonide inhalation therapy, the levels of serum TGF-β1 in pneumonia group were slightly lower,and in bronchiolitis group were lower than 7 days ago but both of them were with no statistical significance (t=0.75,0.93,P＞0.05, P＞0.05).The serum TGF-β1 levels in asthma groupⅠdistinct lower than those of 7 days ago (t=2.04,P＜0.05),whereas the serum TGF-β1 levels in asthma groupⅡslightly decreased after treatment and with no statistical significance (t=0.80,P＞0.05)Conclusion:This study showed that the levels of serum VEGF and TGF-β1 maybe related to the activities of airway inflammation and the severity of asthma attack. They may play a role in the pathogenesis of asthma.It will become to be a new strategy of asthma therapy to regulate the levels of VEGF and TGF-β1 for the prevention and treatment of asthma.