The alarm secretory leukocyte protease inhibitor increases with progressive metabolic dysfunction

Secretory leukocyte protease inhibitor (SLPI) is an alarm antiprotease secreted by neutrophils and mucous membranes that potently inhibits the inflammatory cascade; however, the role of SLPI in human disease remains largely unknown. We hypothesized that SLPI is related to chronic low-grade inflammatory diseases, such as metabolic syndrome (MS) or type-2 diabetes (T2DM).

We examined associations between circulating SLPI (ELISA) and quantitative traits of MS (ATPIII criteria) in 261 Caucasian men with various degrees of metabolic dysfunction. Subjects had neither MS nor T2DM (n=140), either diagnosis (n=44) or both diagnoses (n=77).

Circulating SLPI increased with progressive metabolic dysfunction, with a mean increase of 4.4 ng/ml (95% IC 2.4 to 6.3 ng/ml; p<0.001) for each unit increase in the criteria used to define MS. Circulating SLPI showed independent associations with uric acid [β=5.1 (95% CI 3.4 to 6.7), p<0.00001], serum lipids, pulse pressure and inflammatory markers.

Circulating SLPI increases with progressive metabolic dysfunction and is related to metabolic and inflammatory parameters in men.