Combined blockade of VEGFR-2 and VEGFR-3 inhibits inflammatory lymphangiogenesis in early and middle stages.

PURPOSE: Lymphangiogenesis (LG) accompanies many corneal diseases after inflammatory, infectious, or chemical insults and is a primary mediator of transplant rejection. The purpose of this study was to investigate whether there is a time window for therapeutic intervention of corneal LG and whether a combined blockade of VEGFR-2 and VEGFR-3 effectively suppresses early-, middle-, or late-stage LG. METHODS: Corneal inflammatory neovascularization was induced by a standard suture placement model in mice. Neutralizing antibodies against VEGFR-3 and/or VEGFR-2 were administrated systemically with the treatment started at postoperative day 0, day 7, or day 14. Whole mount corneas were sampled for immunofluorescence microscopic studies using LYVE-1 (a lymphatic marker) antibodies. Digital images were analyzed by software. RESULTS: Both VEGFR-3 and VEGFR-2 were involved in corneal suture-induced inflammatory LG. Their combined blockade led to a significant inhibition of both early- and middle-stage LG while demonstrating no effect on late-stage LG. CONCLUSIONS: Corneal inflammatory LG has a discrete time window for intervention therapy. Although it is important to start the treatment as soon as possible, interventions initiated in the middle of the LG process are still effective. These novel findings will shed some light on our understanding of inflammatory LG and the development of new therapeutic protocols for LG-related diseases at different stages.

Tumor necrosis factor-alpha and interleukin-1 antagonists alleviate inflammatory skin changes associated with epidermal growth factor receptor antibody therapy in mice.

Cancer patients receiving epidermal growth factor receptor (EGFR) antibody therapy often experience an acneiform rash of uncertain etiology in skin regions rich in pilosebaceous units. Currently, this condition is treated symptomatically with very limited, often anecdotal success. Here, we show that a monoclonal antibody targeting murine EGFR, ME1, caused a neutrophil-rich hair follicle inflammation in mice, similar to that reported in patients. This effect was preceded by the appearance of lipid-filled hair follicle distensions adjacent to enlarged sebaceous glands. The cytokine tumor necrosis factor-alpha (TNFalpha), localized immunohistochemically to this affected region of the pilosebaceous unit, was specifically up-regulated by ME1 in skin but not in other tissues examined. Moreover, skin inflammation was reduced by cotreatment with the TNFalpha signaling inhibitor, etanercept, indicating the involvement of TNFalpha in this inflammatory process. Interleukin-1, a cytokine that frequently acts in concert with TNFalpha, is also involved in this process given the efficacy of the interleukin-1 antagonist Kineret. Our results provide a mechanistic framework to develop evidence-based trials for EGFR antibody-induced skin rash in patients with cancer.