Polyamines found in gingival fluid inhibit chemotaxis by human polymorphonuclear leukocytes in vitro

Putrescine and spermidine occur at concentrations approaching 1 mM in gingival fluid at diseased periodontal sites. Previous work demonstrates that these polyamines potentiate Ca2+ signaling in polymorphonuclear leukocytes (PMNs), resulting in enhanced degranulation and superoxide generation. The present study extends this work by characterizing the effects of polyamines on PMN chemotaxis and phagocytosis, in which Ca2+ signaling plays a less defined regulatory role. Putrescine (1 mM) and spermidine (0.1 to 0.5 mM) significantly inhibited chemotaxis to fMet-Leu-Phe and C5a (P < 0.05). This inhibition was not strongly related to any effect polyamines have on PMN adhesion, actin polymerization, or formyl peptide receptor expression. Neither putrescine nor spermidine had a significant impact on phagocytosis of opsonized bacteria by PMNs. Thus, at concentrations similar to those found in gingival fluid, polyamines could potentially inhibit recruitment of PMNs to diseased pockets without impairing their ability to engulf invading bacteria.