The apolipoprotein-al mimetic peptide L4F at a modest dose does not attenuate weight gain, inflammation, or atherosclerosis in Ldlr-null mice

Objective: High density lipoprotein (HDL) cholesterol levels are inversely related to cardiovascular disease risk and associated with a reduced risk of type 2 diabetes. Apolipoprotein A-l (apoA-l; major HDL protein) mimetics have been reported to reduce atherosclerosis and decrease adiposity. This study investigated the effect of L4F mimetic peptide and apoA-I overexpression on weight gain, insulin resistance, and atherosclerosis in an LDL receptor deficient (Ldlr&quot) model fed a high fat high sucrose with cholesterol (HFHSC) diet.

Methods: Studies in differentiated 3T3-L1 adipocytes tested whether L4F could inhibit palmitate-induced adipocyte inflammation. In vivo studies used male Ldir&quotmice fed a HFHSC diet for 12 weeks and were injected daily with L4F (100 μg/ mouse) subcutaneously during the last 8 weeks. Wild-type and apoA-l overexpressing Ldir&qout mice were fed HFHSC diet for 16 weeks.

Results: Neither L4F administration nor apoA-I overexpression affected weight gain, total plasma cholesterol or triglycerides in our studies. While pre-treatment of 3T3-L1 adipocytes with either L4F or HDL abolished palmitate-induced cytokine expression in vitro, L4F treatment did not affect circulating or adipose tissue inflammatory markers in vivo. Neither L4F administration nor apoA-I overexpression affected glucose tolerance. ApoA-l overexpression significantly reduced atherosclerotic lesion size, yet L4F treatment did not affect atherosclerosis.

Conclusion: Out results suggest that neither L4F (100 pg/day/mouse) nor apoA-l overexpression affects adiposity or insulin resistance in this model. We also were unable to confirm a reduction in atherosclerosis with L4F in our particular model. Further studies on the effect of apoA-l mimetics on atherosclerosis and insulin resistance in a variety of dietary contexts are warranted.