Myocardial substrate metabolism influences left ventricular energetics in vivo
Myocardial substrate metabolism influences left ventricular energetics in vivo
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DOI：
10.1152/ajpheart.2000.278.4.h1345
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发表时间：
2000-04-01
影响因子：
4.8
通讯作者：
Myrmel, T
中科院分区：
文献类型：
--
作者：
Korvald, C;Elvenes, OP;Myrmel, T
心肌耗氧量(MVO(2))与左心室压力-容积面积(PVA)的关系假定不受底物的改变，尽管磷酸盐与氧气的比率不同，且可能与脂肪酸消耗相关的MVO(2)过多。这一假设的有效性在体内得到了检验。用电导-压力复合导管对8只麻醉猪的左心室容量和压力进行了测定。根据冠脉流量和动脉-冠状静脉窦氧分压差计算MVO(2)。用葡萄糖-胰岛素-钾(GIK)或脂内肝素(IH)随机顺序输注改变代谢，并用[C-14]葡萄糖和[H-3]油酸盐示踪。观察到葡萄糖和脂肪酸氧化的深刻变化。在GIK和IH输注期间，收缩性、冠脉流量和MVO(2)-PVA关系的斜率没有变化，无PVA时的MVO(2)为0.16+/-0.13J。节拍(-1)。IH组较GIK组高100g~(-1)(P=0.001)，增加48%。这项研究证明了心肌中葡萄糖氧化的显著能量优势，深刻地影响了MVO(2)-PVA关系。这可能在一定程度上解释了诸如肾上腺素能药物和缺血等增强血脂的干预措施的“耗氧”效应。
The myocardial oxygen consumption (MVo(2)) to left ventricular pressure-volume area (PVA) relationship is assumed unaltered by substrates, despite varying phosphate-to-oxygen ratios and possible excess MVo(2) associated with fatty acid consumption. The validity of this assumption was tested in vivo. Left ventricular volumes and pressures were assessed with a combined conductance-pressure catheter in eight anesthetized pigs. MVo(2) was calculated from coronary flow and arterial-coronary sinus O-2 differences. Metabolism was altered by glucose-insulin-potassium (GIK) or Intralipid-heparin (IH) infusions in random order and monitored with [C-14]glucose and [H-3]oleate tracers. Profound shifts in glucose and fatty acid oxidation were observed. Contractility, coronary flow, and slope of the MVo(2)-PVA relationship were unchanged during GIK and IH infusions, MVo(2) at zero PVA (unloaded MVo(2)) was 0.16 +/- 0.13 J . beat(-1) . 100 g-(1) higher during IH compared with GIK infusion (P = 0.001), a 48% increase. The study demonstrates a marked energetic advantage of glucose oxidation in the myocardium, profoundly affecting the MVo(2)-PVA relationship. This may in part explain the "oxygen-wasting" effect of lipid-enhancing interventions such as adrenergic drugs and ischemia.