APOA1 and atherosclerosis: We have also shown that the decrease in plasma ceramides in morbidly obese patients after bariatric surgery coincided with decreased ApoB levels, a reduced ApoB/ApoA1 ratio and a reduction in the overall CVD risk, suggesting that in addition to regulating HDL metabolism sphingolipids may also contribute to atherosclerosis through their effect on ApoB metabolism [20].