Background: Hepatocyte growth factor (HGF) has a significant effect on the regeneration of epithelial and endothelial cells. Studies have also shown an important role of HGF in wound healing and organ regeneration. Because recent studies indicate that polymorphonuclear leukocytes (PMNLs) store HGF in their specific granules and that HGF can be degranulated in the inflammatory tissue in which activated PMNLs migrate, we evaluated the storage and release of HGF in PMNLs from patients with systemic inflammatory response syndrome (SIRS) and attempted to examine the role of HGF from PMNLs in the systemic inflammatory process.
Methods: Twenty-four patients with SIRS (serum C-reactive protein, 20.2 +/- 12.4 mg/dL [mean +/- SD]) and 18 healthy volunteers were studied. HGF in PMNLs was measured by flow cytometry by using a monoclonal antibody to HGF. The oxidative activity in PMNLs was also measured by flow cytometry. Serum HGF, interleukin (IL)-6, and IL-8 levels in each patient were measured by enzyme-linked immunosorbent assay. HGF degranulation from PMNLs was evaluated in 10 patients.
Results: Immunocytochemistry under fluorescence microscopy revealed enhanced expression of HGF in the granules of PMNLs. HGF in PMNLs significantly increased in patients with SIRS compared with PMNLs from healthy volunteers (SIRS, 171.0 +/- 6.6 fluorescence/cell; control, 130.7 +/- 3.8 fluorescence/cell). N-formylmethionyl-leucyl-phenylalanine and lipopolysaccharide stimulation induced further increase of HGF fluorescence in PMNLs from patients. HGF degranulation from PMNLs was also significantly enhanced in patients. Moreover, oxidative activity in PMNLs was significantly enhanced in patients with SIRS. Plasma HGF (pHGF) correlated positively with IL-6 and IL-8 levels in patients (pHGF and IL-6, gamma = 0.635, p < 0.05; pHGF and IL-8, gamma = 0.827, p < 0.01), but these values did not correlate with HGF in PMNLs.
Conclusion: Activated PMNLs in SIRS patients increased HGF in their granules and demonstrate enhanced degranulation of HGF. The release of HGF from migrated PMNLs in the inflammatory tissue may play an important role in wound healing and organ regeneration under those conditions.