SPP1 and Insulin resistance: Given the increased insulin levels and reduced insulin sensitivity in aged Ldlr−/− mice, we examined whether adipose tissue from young or aged Ldlr−/− mice exhibited an altered ability to produce CCL‐2, IL‐6 and OPN, inflammatory proteins, which have all been implicated in insulin resistance (Kanda et al., 2006; Pedersen & Febbraio, 2007; Kiefer et al., 2010).