Nelson Robert H, Prasad Abhiram, Lerman Amir, Miles John M
Endocrine Research Unit, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Diabetes. 2007 Feb;56(2):527-30. doi: 10.2337/db06-1552.
Animal studies indicate that oversupply of fatty acids derived from the action of cardiac lipoprotein lipase (LPL) on plasma lipoproteins may contribute to myocardial dysfunction. However, the contribution of circulating triglycerides to myocardial fatty acid supply in humans is not known. Six postabsorptive nondiabetic subjects who were scheduled for diagnostic coronary angiography were studied. (14)C oleate and a lipid emulsion labeled with (3)H triolein were infused to assess myocardial uptake of free fatty acids (FFAs) and triglycerides, as well as myocardial spillover of LPL-generated fatty acids. Six paired blood samples were taken from the femoral artery and the coronary sinus. Coronary sinus concentrations of unlabeled triglycerides were slightly, but not significantly, lower than arterial (P = 0.12), whereas labeled triglyceride concentrations were significantly lower in the coronary sinus than in the artery (P < 0.05; extraction fraction congruent with 11%). Triglycerides and FFAs accounted for approximately 17% and approximately 83%, respectively, of myocardial fatty acid uptake. Systemic and myocardial fractional spillover of LPL-generated fatty acids was 49.0 +/- 7% and 34.7 +/- 13%, respectively. The myocardium was a minor contributor to systemic triglyceride uptake ( approximately 3%) and a trivial contributor to systemic FFA production ( approximately 0.5%). These results indicate that circulating triglycerides may be a significant source of fatty acids for myocardial respiration.
动物研究表明，心脏脂蛋白脂肪酶（LPL）作用于血浆脂蛋白产生的脂肪酸供应过多可能导致心肌功能障碍。然而，循环甘油三酯对人类心肌脂肪酸供应的贡献尚不清楚。对六名计划进行诊断性冠状动脉造影的空腹非糖尿病受试者进行了研究。输注（14）C油酸酯和用（3）H三油酸甘油酯标记的脂质乳剂，以评估心肌对游离脂肪酸（FFA）和甘油三酯的摄取，以及LPL产生的脂肪酸的心肌溢出。从股动脉和冠状窦采集六对血样。未标记甘油三酯的冠状窦浓度略低于动脉，但无显著差异（P = 0.12），而标记甘油三酯浓度在冠状窦中显著低于动脉（P < 0.05；提取率约为11%）。甘油三酯和FFA分别约占心肌脂肪酸摄取的17%和约83%。LPL产生的脂肪酸的全身和心肌分数溢出分别为49.0 +/- 7%和34.7 +/- 13%。心肌对全身甘油三酯摄取的贡献较小（约3%），对全身FFA产生的贡献微不足道（约0.5%）。这些结果表明，循环甘油三酯可能是心肌呼吸脂肪酸的重要来源。
