MBTPS1 and hydrops fetalis: ,64,65 In mouse models, the accumulation of cardiac Cer through either the increased entry of FAs in cardiomyocytes, the increased Cer production through de novo biosynthesis, or the decreased Cer breakdown have all been directly related to the development of HF with reduced LVEF.66, 67, 68 Our data showed that nonresponders tended to have higher levels of cardiac Cer compared to nonfailing donor hearts, coupled with increased levels of upstream SLs such as dhCer and Sa1P and downstream SLs such as S1P compared to responders.