Figure 2.

The relationship between cardiomyocyte membrane fatty acid composition and contractile dysfunction. Cardiomyocyte membrane fatty acid composition, the balance of SFA and MUFA, are well maintained by the SIRT1-LXR-SCD1 axis. SFA overload decreases the activity of the SIRT1-LXR-SCD1 axis, which leads to a high ratio of membrane SFA/MUFA. An increase in membrane SFA/MUFA ratio triggers ER stress and relates to cardiac contractile dysfunction, mainly diastolic dysfunction. Intervention with either SIRT1 activation or MUFA supplementation during SFA overload improves membrane SFA/MUFA ratio, ER stress, and contractile dysfunction. A black arrow facing upwards indicates an increase and downwards indicates a decrease. ER, endoplasmic reticulum; LXR, liver X receptor; MUFA, monounsaturated fatty acid; SCD1, stearoyl-CoA desaturase I; SFA, saturated fatty acid; and SIRT1, sirtuin1.