Chronic hyperglycemia is thought to be important in the development of diabetic neovascularization but the mechanisms involved remain poorly understood. Interleukin-8 (IL-8) is a leukocyte chemokine and activating agent with angiogenic properties that is present in diabetic vitreous and may play a role in diabetic vasculopathy. We studied IL-8 and monocyte chemotactic protein-1 (MCP-1) production by human retinal pigment epithelial (hRPE) cells exposed to glycated human serum albumin (GHSA). Enzyme-linked immunoassay GHSA (500 micrograms/mL)-treated hRPE cells secreted levels of IL-8 and MCP-1 detectable within 4 h and reached 26.0 +/- 1.3 and 42.2 0.4 ng/10(6) cells/mL after 24 h, respectively. Induction of IL-8 and MCP-1 by GHSA at concentrations ranging from 62.5 to 3,000 micrograms/mL exhibited dose-dependent kinetics. The GHSA-induced chemokine secretion by hRPE was almost completely inhibited by actinomycin D and cycloheximide, suggesting that de novo mRNA and protein synthesis are necessary for the GHSA-induced IL-8 and MCP-1 production. Northern blot analysis of GHSA-induced hRPE IL-8 and MCP-1 mRNA expression corresponded to the time- and dose-dependent increases measured by enzyme-linked immunosorbent assay. High concentrations of glucose (20 mM; 360 mg/dl) increased GHSA-induced hRPE IL-8 and MCP-1 secretion, whereas added insulin (0.5 ng/mL) inhibited IL-8 but not MCP-1 protein secretion and mRNA expression. GHSA also induced hRPE to secrete GRO-alpha, RANTES, and NAP-2 chemokines. GHSA induction of hRPE chemokines further suggests a role for the hRPE in leukocyte infiltration, vascular injury, and neovascularization.