i) Comparison between p16Ink4a mRNA levels of young (3 months old) and old INK-ATTAC mice (28-29 month old) treated with vehicle or AP20187. Data are mean ± SEM of n = 5-8 mice per age group; j) % of TAF positive hepatocytes in old INK-ATTAC mice (28-29 months old) treated with vehicle or AP20187. Data are mean ± SEM of n = 5-6 mice per group; k) Liver neutrophils (Ly6G) in old INK-ATTAC mice (28-29 months old) treated with vehicle or AP20187. Data are mean ± SEM of n = 5-7 mice per group; 