Abstract
Purpose:
The purpose of this study is to investigate the characteristics of human macrophages under ocular diabetic condition. Since increased advanced glycation endproducts (AGEs) are major causes of diabetic microvasculopathy, macrophages characters induced by AGEs were analyzed and were compared to that induced by other cytokines.
Methods:
Human monocyte cell line THP-1 was stimulated by PMA (Phorbol 12-myristate 13-acetate). PMA-stimulated THP-1 was used as differentiated macrophages in vitro. PMA-THP-1 cells were cultured with AGEs or various cytokines (M1 inducer: IFN-g, M2 inducer: IL-4 & IL-13, RPE secreting cytokine: PGE2). ELISA or FACS was performed in order to measure cytokines and chemokines in the cell supernatants. Quantitative mRNA expressions were also examined by RT-PCR.
Results:
VEGF was highly secreted by PMA-stimulated THP-1 in the presence of AGEs or PGE2. The mRNA expression of vegf was higher, while ccr2 was less than control respectively. Furthermore, not only massive secretion of IL-8 but also multiple increased productions of TNF-α, IL-1β, IL-6, IL-10, MCP-1, RANTES were induced by AGEs.
Conclusions:
Pro-angiogenic myeloid cells are presumably induced through intraocular cytokines or AGEs directly. Together with robust VEGF and IL-8 secretions, multiple chemokines or cytokines released from myeloid cells may orchestrate diabetic ocular pathology.