GDF15 and atherosclerosis: As GDF15 (growth differentiation factor 15) fits this description and is produced by adipose tissue macrophages (among other cell types) and has also immunoinhibitory effects,38–44 we assessed the GDF15 levels in the atherosclerosis initiation study (female LDLr−/− fed a WTD and treated for 7 weeks), preexisting adipose tissue study (male LDLr−/− mice on a WTD for 11 weeks and treated the last 7 weeks), and short-term treatment study (male LDLr−/− on a WTD for 5 weeks, treated for 1 day or 1 week).