Figure 3. Top lipid species changed with age in the skeletal muscle mitochondrial lipidome. Scatter plots (A-C) display the top three lipids that increase in abundance in aged 78 weeks skeletal muscle mitochondria (n=10) compared with young 4-11 weeks skeletal muscle mitochondria (n=10). The scatter plots (D-F) display the top three lipids that decrease in abundance in the aged skeletal muscle mitochondria compared to the young skeletal muscle mitochondria. (A) The lipid m/z 642.568 tentatively identified as ceramide (36:0) increases in abundance by a fold change of 12.37 in the aged skeletal muscle mitochondria. (B) The lipid m/z 1466.917 tentatively identified as cardiolipin (72:10) increases in abundance by a fold change of 9.31 in the old skeletal muscle mitochondria. (C) The lipid m/z 874.537 tentatively identified as phosphatidylcholine (42:11) increases in abundance by a fold change of 7.52 in aged skeletal muscle mitochondria. (D) The lipid m/z 564.305 tentatively identified as lyso-phosphatidylcholine (20:5/0:0) decreases in abundance by a fold change of 23.19 in aged skeletal muscle mitochondria. (E) The lipid m/z 1504.035 tentatively identified as phosphatidylethanolamine (36:3) decreases in abundance by a fold change of 12.96 in aged skeletal muscle mitochondria. (F) The lipid m/z 331.263 tentatively identified as docosatetraenoic acid decreases in abundance by a fold change of 10.12 in aged skeletal muscle mitochondria. Scatter plots display the abundance ± SEM. We used the Wilcoxon rank test and Bonferroni correction (p<0.15). Lipids were identified using Lipid Maps and Human Metabolome databases. Refer to Supplementary Tables 1 and 2 for the top 50 lipid changes. Abbreviations: ceramide (cer), cardiolipin (CL), phosphatidylcholine (PC), lysophosphatidylcholine (lysoPC) and phosphatidylethanolamine (PE).