HUMAN SATELLITE CELL-PROLIFERATION IN-VITRO IS REGULATED BY AUTOCRINESECRETION OF IL-6 STIMULATED BY A SOLUBLE FACTOR(S) RELEASED BY ACTIVATED MONOCYTES

We previously showed that macrophages, besides their scavenger role, s electively induce rat myoblast proliferation in vitro by releasing sol uble factors. In this paper we demonstrate a relationship between huma n-activated monocytes and increased human myoblast proliferation due t o IL-6 autocrine secretion by satellite cells. Indeed in the supernata nts of muscle cultures treated with activated monocyte-conditioned med ium we show by means of an ELISA quantitation a higher autocrine secre tion of IL-6 associated with increased myoblast proliferation. This su ggests that a growth factor(s) secreted by activated monocytes stimula tes IL-6 production by myoblasts and then regulates proliferation of s atellite cells. (C) 1995 Academic Press, Inc.