Interleukin-6 stimulates proliferation of cultured vascular smooth muscle cells independently of interleukin-1 beta.

The effects of interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) on proliferation of cultured vascular smooth muscle cells (VSMCs) were investigated. Treatment with IL-6 caused a rapid increase in the c-myc mRNA level, and resulted in increases in DNA synthesis and cell number. IL-1 beta stimulated the DNA synthesis of the cells. EGF showed synergistic and PDGF or IL-1 beta showed additive effects with IL-6 on the DNA synthesis. These results suggest that IL-6, independently of IL-1 beta, may be important in the proliferation of VSMCs.