SPHK2 and atherosclerosis: To investigate roles of the two SphK isoforms in atherosclerosis, we fed four mice groups with different SphK genotypes, i.e. Sphk1+/+; Sphk2+/+ (hereafter abbreviated as Sphk2+/+), Sphk1+/+; Sphk2+/− (Sphk2+/−), Sphk1+/+; Sphk2−/− (Sphk2−/−), and Sphk1−/−; Sphk2+/+ (Sphk1−/−) in the Apoe−/− background, on a WD for 12 weeks, followed by determinations of the aortic plaque lesion areas.