  We present here a population structured model to describe the dynamics of
macrophage cells. The model involves the interactions between modified LDL,
monocytes/macrophages, cytokines and foam cells. The key assumption is that the
individual macrophage dynamics depends on the amount of lipoproteins it has
internalized. The obtained renewal equation is coupled with an ODE describing
the lipoprotein dynamics. We first prove global existence and uniqueness for
the nonlinear and nonlocal system. We then study long time asymp-totics in a
particular case describing silent plaques which undergo periodic rupture and
repair. Finally we study long time asymptotics for the nonlinear renewal
equation obtained when considering the steady state of the ODE. and we prove
that ....
