Ultrahigh dose gentamicin alters inflammation and angiogenesis in vivo and in vitro

Skin quality outcome after skin grafting is adversely affected by wound bed inflammation. Neomycin, gentamicin, and other aminoglycoside antibiotics are known to modulate inflammation, and topical application affords the use of higher doses than are possible to use systemically. Previous data suggest that clinically relevant doses of neomycin, but not gentamicin, may impair angiogenesis, which is critical to the durable survival of skin grafts. The role of gentamicin at ultrahigh doses compared with clinically relevant neomycin doses in regulating inflammatory expression and angiogenesis has been examined. In a porcine skin replacement excisional wound model, continuous exposure to gentamicin increased anti-angiogenic and inflammatory expression at 7 days postgrafting. In in vitro studies, gentamicin also impaired angiogenesis in a human umbilical vein endothelial cell (HUVEC) tube formation model, increased the expression of the anti-angiogenic gene C-X-C motif chemokine 10 (CXCL10) in HUVECs and macrophages, and increased pro-inflammatory cytokine expression of macrophages in a dose-dependent manner. Neomycin exerted similar effects in vitro at clinically relevant doses on HUVEC tube formation and macrophage pro-inflammatory expression. CXCL10 was upregulated in macrophages, but did not exhibit a change in HUVECs with neomycin treatment. Ultrahigh doses of gentamicin and clinically relevant doses of neomycin affect inflammation and angiogenesis in in vivo and in vitro models. These findings suggest that topical administration of aminoglycosides have the potential to adversely influence early skin graft survival.