ABCG1 and diabetes mellitus: For example, insulin decreases human macrophage ABCA1 and ABCG1 gene expression in vitro.[29] Animal studies indicate that complications such as nephropathy independently reduce macrophage ABCA1 and increase cellular cholesterol content.[30] Treatment of nephropathy in this study restored ABCA1-mediated cholesterol efflux in macrophages.[30] The present study has the advantage of having matched controls and patients who were drug naive and free of diabetes related complications.