Increases in peripheral SIRT1: a new biological characteristic of asthma

Silent information regulator 1 (SIRT1) is a class III histone deacetylase that exerts both anti-inflammatory and anti-aging effects. However, no data are available regarding SIRT1 expression in patients with asthma. Here, we studied SIRT1 levels in the serum of patients with asthma and analysed the distribution of SIRT1 in both the serum and the lungs in an asthmatic mouse model to determine its clinical significance.

Serum SIRT1 levels, total immunoglobulin E (IgE) levels and peripheral blood eosinophil percentages as well as pulmonary function were quantified in 97 patients with asthma and 118 healthy volunteers. BALB/c mice were sensitized and challenged using ovalbumin (OVA) to produce the asthmatic model, and SIRT1 levels in both the serum and the lung tissues were subsequently measured.

The serum SIRT1 levels were significantly elevated in the patients with asthma compared with the controls. Serum SIRT1 levels positively correlated with total IgE levels and negatively correlated with pulmonary function. In the OVA-sensitized and challenged mice, an increased serum SIRT1 level was confirmed, whereas decreased SIRT1 expression was observed in the lung tissues.

These data indicate that lung SIRT1 expression decreased while serum SIRT1 increased in the setting of asthma. Serum SIRT1 levels correlate positively with both IgE levels and negatively with pulmonary function, suggesting that increased peripheral SIRT1 levels represent a new biological characteristic of asthma. Increased serum SIRT1 may be an auxiliary index for the diagnosis of asthma and elevating lung SIRT1 levels may be a new strategy for asthma therapy.