VEGF levels increased in children with asthma
MedWire News: Serum levels of vascular endothelial growth factor (VEGF) are elevated in children with asthma, and may result in increased airway responsiveness through mechanisms related to airway inflammation or increased permeability of airway vasculature, say researchers.
“VEGF increases vascular permeability and angiogenesis, leads to mucosal edema, narrows the airway diameter, and reduces airway flow,” explain Jin Tae Choung (Korea University Anam Hospital, Seoul, Korea) and colleagues in the Annals of Allergy, Asthma and Immunology.
The team investigated VEGF levels and relationships between VEGF levels and airway responsiveness to methacholine and adenosine monophosphate (AMP) challenge in 31 children, aged 7 to 12 years, with the respiratory condition and 26 healthy age-matched controls.
The researchers note that challenges with methacholine cause airway narrowing mainly by direct action on receptors of airway smooth muscle, whereas challenges with AMP are thought to act primarily on other cells, thus initiating processes that indirectly lead to smooth muscle contraction.
All the participants provided blood samples for the measurement of total eosinophil counts, serum eosinophil cationic protein (ECP) levels, and VEGF levels, and underwent skin prick testing for the evaluation of atopy. Children with asthma also underwent methacholine and AMP bronchial challenges, with spirometry performed before and after these tests.
The researchers found that children with asthma had a significantly higher mean VEGF level than controls, at 361.2 versus 102.7 pg/ml.
In children with asthma, blood eosinophil and serum ECP levels significantly inversely correlated with AMP provocation concentration, which caused a decrease in FEV1 of 20% (PC20). However, blood eosinophil and serum ECP levels did not correlate with methacholine PC20.
Serum VEGF levels significantly correlated with airway responsiveness to AMP, but not with responsiveness to methacholine.
Tae Choung and team comment: “Level of VEGF may be associated with the pathogenesis of childhood asthma through increased permeability and airway inflammation and may be better reflected by airway responsiveness to AMP rather than to methacholine.
“These findings indicate that methacholine challenge is a better physiologic marker of smooth muscle dysfunction as opposed to inflammation.”
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By Mark Cowen