Purpose: The goal of the study was to examine the effects of sivelestat sodium hydrate (sivelestat), a neutrophil elastase inhibitor, on production of cytokines in granulocytes and monocytes, using flow cytometry after cytokine staining in whole blood culture.
Methods: Blood samples were collected from healthy volunteers. Vehicle (control group), lipopolysaccharide (LPS) (LPS group), or LPS + sivelestat (sivelestat group) were added to the whole blood, followed by addition of a protein transport inhibitor in each group. After incubation, staining for cytokines retained in the cells was performed by addition of an anti-interleukin 8 (IL-8) or anti-tumor necrosis factor-α (TNF-α) antibody. The cells were then analyzed using flow cytometry.
Results: Granulocytic production of IL-8 induced by 1 ng/ml LPS was significantly (P < 0.05) inhibited by treatment with 1 μg/ml sivelestat, and upregulation of IL-8 by 10 ng/ml LPS was also significantly (P < 0.05) suppressed by 1 and 10 μg/ml sivelestat. Addition of 10 or 100 μg/ml sivelestat significantly (P < 0.05) inhibited the production of TNF-α from granulocytes induced by 10 ng/ml LPS. Sivelestat did not significantly inhibit LPS-induced monocytic production of TNF-α and IL-8.
Conclusion: Suppression of granulocytic production of IL-8 and TNF-α by sivelestat suggests that this drug may be useful for treatment of morbid conditions involving IL-8 and TNF-α at onset.