MedWire News: Levels of the inflammatory mediator high mobility group box 1 (HMGB-1) and its endogenous decoy inhibitor, endogenous secretory receptor for advanced glycation end products (esRAGE), are increased in patients with asthma, study results show.
The team also found that an imbalance between HMGB-1 and esRAGE is significantly associated with disease severity in asthma patients.
Tetsuya Watanabe (Osaka City University, Japan) and colleagues explain that, recently, "HMGB-1 has attracted much attention as an important mediator in inflammatory diseases such as atherosclerosis, arthritis, collagen disease, cancers, sepsis, and acute lung injury."
But they add: "The role of HMGB-1 in the pathogenesis of asthma and the involvement of the esRAGE feedback system in HMGB-1-mediated inflammatory responses in asthma are not yet fully understood."
To compare HMGB-1 and esRAGE levels between asthma patients and those without the respiratory condition, and to investigate correlations with asthma severity, the team enrolled 44 asthmatic patients and 15 healthy controls who were aged an average of 34 and 42 years, respectively.
Analysis of sputum samples collected from the participants revealed that median HMGB-1 and esRAGE levels were significantly higher in asthma patients than controls, at 91.5 ng/ml versus 0.0 ng/ml, and 110.5 versus 12.0 pg/ml, respectively.
In asthma patients, HMGB-1 levels were inversely correlated with percentage of predicted FEV1 and FEV1/forced vital capacity ratio.
Furthermore, increased HMGB-1 levels were associated with increased asthma severity, but esRAGE levels were not significantly associated with disease severity.
The researchers also found that there was a significant positive correlation between HMGB-1 levels and percentage of neutrophils in induced sputum from asthma patients. But there was no significant correlation between esRAGE levels and percentage of neutrophils.
"Our findings suggest that the HMGB-1 is a mediator of neutrophilic airway inflammation in asthma and that imbalance between HMGB-1 and esRAGE is related to the severity of asthma," comment Watanabe and team.
They conclude that, although further research is needed, "combined measurement of HMGB-1 and esRAGE may be novel biomarkers in asthma with severe airflow limitation."
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