Peyronie's disease (PD) is characterized by fibrosis in the tunica albuginea (TA) of the penis, which becomes bent as a result, We have previously shown that transforming growth factor-beta1 (TGF-beta1) is upregulated in the TA of patients with PD and can initiate PD-like lesions in rat models. In this study we isolated three types of fibroblasts: P cells from the lesions of PD patients, C cells from the normal-appearing areas of the TA of the same patients, and N cells from the TA of patients without PD. We examined these cells for the expression of two fibrogenic cytokines, connective tissue growth factor (CTGF). and Monocyte Chemoattractant Protein 1 (MCP-1). We found that CTGF was expressed at similar levels in P, C, and N cells, whereas MCP-1 was significantly more expressed in P cells than in C cells and more in C cells than in N cells. Higher MCP-1 expression was also found in the lesions than in normal TA. Treatment with TGF-1-induced higher expression of MCP-1 but not CTGF in all three types of cells, with C cells being the most responsive. Based on these observations, we propose that MCP-1 could be a novel therapeutic target in PD. (C) 2002 Elsevier Science (USA). All rights reserved.