病毒性心肌炎小鼠心肌线粒体结构和功能变化

目的:探讨病毒性心肌炎(VMC)小鼠心肌线粒体结构和功能变化。方法:雄性Balb/c小鼠随机分为柯萨奇B3病毒(CVB3)感染组和对照组。分别采用电镜和形态计量学方法观察心肌线粒体形态、数量和膜磷脂定位,酶细胞化学法分析线粒体细胞色素氧化酶(CCO)和琥珀酸脱氢酶(SDH)活性,反相高效液相色谱法测定心肌组织腺苷酸(ATP、ADP和AMP)含量。结果:CVB2感染组小鼠心肌线粒体大量破坏,膜磷脂严重缺失、定位改变,CCO和SDH活性降低,腺苷酸(ATP、ADP和AMP)含量下降。结论:VMC心肌线粒体结构严重破坏、功能明显下降,心肌细胞存在产能障碍。     

川芎嗪通过抑制环氧化酶2/前列腺素E2途径减轻血管紧张素Ⅱ诱导的心肌肥大

目的:探究川芎嗪通过抑制环氧化酶2(COX2)/前列腺素E2(PGE2)途径减轻血管紧张素Ⅱ(AngⅡ)诱导的心肌肥大。方法:培养小鼠正常心肌细胞H9c2作为对照组,用0.1μmol/L的AngⅡ诱导建立H9c2肥大模型作为模型组,用低剂量(0.01 mmol/L)、中剂量(0.1 mmol/L)、高剂量(1 mmol/L)的川芎嗪干预AngⅡ诱导的H9c2细胞作为低剂量川芎嗪组、中剂量川芎嗪组、高剂量川芎嗪组。甲基噻唑基四唑(MTT)法检测细胞活性;Leica Qwin V3图像分析系统测量细胞表面积;激光共聚焦显微镜检测细胞[Ca²⁺]i;采用比色法测定细胞一氧化氮(NO)含量和一氧化氮合酶(NOS)活性;酶联免疫吸附法(ELISA)测定细胞转化生长因子β₁(TGF-β₁)含量;反转录聚合酶链式反应(qRT-PCR)检测细胞COX2和PGE2 mRNA表达;蛋白质免疫印迹法(WesternBlot)检测细胞COX2和PGE2蛋白表达。结果:与对照组比较,模型组H9c2细胞活性、细胞NO含量和NOS活性降低(P<...     

上调微小RNA-142-3p对心肌肥厚中线粒体功能的影响

目的观察微小RNA(microRNA,miR)-142-3p对血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)诱导的心肌肥厚中线粒体功能的影响。方法我们使用Sprague-Dawley(SD)大鼠的乳鼠心肌细胞,细胞培养后分成4组:空白组;AngⅡ组;miR nc+AngⅡ组;miR-142-3p mimic+AngⅡ组。分别往细胞中转染相同浓度的miR-142-3p和miR nc质粒6 h,实时定量聚合酶链反应(real-time polymerase chain reaction,rt-PCR)检测实验组miR-142-3p mRNA表达增多,提示细胞质粒转染成功,再用10-6mol/L浓度的AngⅡ诱导细胞48 h,使用线粒体MitoRed Tracker处理细胞30 min,共聚焦显微镜观察细胞中线粒体密度的变化;使用流式细胞仪检测线粒体膜电位变化。结果与空白组相比,AngⅡ组的线粒体膜电位减低(n=3,P0.01);与AngⅡ+miR nc组相比,AngⅡ+miR-142-3p组的线粒体膜电位增加(n=3,P0.01)。与空白组相比,AngⅡ组的线粒体荧光数量减低(n=3,P0.01);与AngⅡ+miR nc组相比,AngⅡ+miR-142-3p组的线粒体荧光数量增加(n=3,P0.01)。结论在AngⅡ诱导心肌肥大过程中miR-142-3p对心肌线粒体具有保护作用。     

温补心阳和肾阳方对心力衰竭大鼠心功能和心肌磷酸腺苷含量的影响

目的研究温补心阳和肾阳方对心力衰竭大鼠心功能和心肌磷酸腺苷含量的影响。方法采用结扎冠状动脉前降支术制备心力衰竭大鼠模型,用温补心阳和温补肾阳方于术后2周灌胃,以假手术组为空白对照组,曲美他嗪为阳性药物对照组。给药8周,采用酶联免疫吸附法检测心梗后心力衰竭大鼠药物干预前后脑钠肽(BNP)水平,测定治疗后血流动力学改变,包括心率(HR)、左室收缩压(LVSP)、左室舒张压(LVEDP)、左室内压上升下降最大速率(±LVdp/dtmax),并行高效液相法测定心肌组织中AMP、ADP、ATP的含量。结果对心力衰竭大鼠心功能的影响,温补心阳和肾阳组较模型组,显著降低BNP水平(P<0.01),改善心肌收缩、舒张功能。而肾阳组大鼠LVSP、+LVdp/dtmax较心阳组升高(P<0.05),LVEDP、-LVdp/dtmax、HR、BNP较心阳组降低(P<0.05)。对心力衰竭大鼠心肌磷酸腺苷含量的影响:温补心阳和肾阳组大鼠较模型组心肌AMP、ADP降低(P<0.05),ATP含量升高,而肾阳组大鼠心肌ATP含量显著高于模型组(P<0.01),较心阳组更接近曲美他嗪和假手术组。结论温补心阳和温补肾阳可改善心力衰竭大鼠能量代谢,提高心功能,其中以温补肾阳作用更显著。     

外源性硫化氢对心肌肥大的保护作用

目的:研究外源性硫化氢(H2S)对血管紧张素Ⅱ(AngⅡ)引起的心肌细胞肥大的保护作用。方法:将1~3日龄Wistar乳鼠心肌细胞培养48 h,随机分为正常对照组、AngⅡ组、硫氢化钠组(NaHS组),其中AngⅡ组和NaHS组的心肌细胞经AngⅡ干预48 h制备心肌肥大细胞模型,通过鬼笔环肽染色判定模型成功。NaHS组在肥大基础上用NaHS干预48 h。JC-1染色观察各组线粒体膜电位势能变化。Mitosox测定各组活性氧(ROS)水平。Western blot检测心肌细胞相关蛋白表达水平。结果:AngⅡ能够建立大鼠心肌肥大细胞模型。对照组、NaHS组线粒体膜电位势能均明显高于AngⅡ组。NaHS组ROS、NADPH氧化酶(NOX)4水平均低于AngⅡ组。结论:H2S可减少心肌细胞线粒体氧化应激,减少心肌细胞凋亡。     

应用压力-容积环评价曲美他嗪对大鼠心肌顿抑的影响

目的应用压力-容积环评价曲美他嗪对大鼠心肌顿抑的影响及可能机制。方法 30只雄性SD大鼠,随机等分成3组:对照组、心肌顿抑组(生理盐水2 mL)和曲美他嗪组(曲美他嗪片3 mg/kg)。结扎冠状动脉左前降支20 min再灌注120 min,制作大鼠心肌顿抑模型(对照组只穿线不结扎)。用压力-容积系统动态观察心率、左心室收缩期末压、收缩期末压力容积、左心室舒张期末压及舒张期末压力容积等血流动力学变量以及压力-容积环变化,并应用软件PowerLab系统离线分析;再灌注结束后测定大鼠心肌组织中ATP含量、ATP酶活性及磷酸果糖激酶活性,并应用体视学方法定量分析大鼠心肌线粒体的变化。结果与心肌顿抑组相比,曲美他嗪组舒张期末压、收缩期末容积、前负荷补充搏功均显著降低(P<0.01),舒张期末压力-容积也降低(P<0.05);舒张期末容积、收缩期末压力容积均显著升高(P<0.01),ATP含量及ATP酶(Ca2+-Mg2+ATPase和Na+-K+ATPase)活性增加(P<0.05);磷酸果糖激酶活性显著增加(P<0.01);心肌线粒体损伤显著减轻(P<0.01)。结论曲美他嗪可以通过改善能量代谢降低心肌顿抑的发生,压力-容积环能准确敏感地评价心功能。     

缬沙坦抑制血管紧张素Ⅱ刺激下心肌细胞缝隙连接蛋白43表达的上调

目的研究血管紧张素Ⅱ(AngⅡ)刺激心肌细胞肥大后,缝隙连接蛋白43(Cx43)表达的变化及缬沙坦的干预作用。方法分离培养大鼠心肌细胞,分为对照组,AngⅡ组(AngⅡ1.0×10~6mol/L)和缬沙坦组(AngⅡ1.0×10~6mol/L+缬沙坦1.0×10~6mol/L)。另外将缬沙坦以1.0×10~5、1.0×10~6和1.0×10~7mol/L刺激分为A组、B组和C组。先用AngⅡ诱导心肌肥大24 h后,采用免疫荧光法和免疫印迹蛋白法观察心肌细胞Cx43蛋白表达以及缬沙坦的干预作用。结果与对照组比较,AngⅡ组心肌细胞明显肥大,蛋白质含量明显增加,Cx43蛋白表达明显上调;与AngⅡ组比较,缬沙坦组拮抗AngⅡ刺激下Cx43蛋白的上调,并呈明显浓度依赖性下降。与A组比较,B、C组Cx43蛋白表达下降(P<0.05)。结论 AngⅡ刺激心肌细胞24 h后,通过AngⅡ1型受体信号通路,导致Cx43蛋白表达浓度依赖性上调,缬沙坦明显抑制其上调,Cx43上调可能与心肌肥大过程有关。     

曲美他嗪对缺氧诱导原代大鼠心肌细胞凋亡的影响

目的研究曲美他嗪对缺氧诱导的心肌细胞凋亡及线粒体能量代谢改变的影响。方法采用胰酶和胶原酶联合消化的方法,提取大鼠原代心肌细胞,三气培养箱模拟缺氧损伤。MTT和Hoechst染色检测细胞活性和凋亡,TMRE染色检测线粒体膜电位,Oxygraph-2k细胞呼吸测量仪检测态3、态4呼吸和呼吸控制率,Western blot检测Caspase-3、细胞色素C以及线粒体呼吸链复合酶体Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ蛋白表达水平的变化。结果缺氧能够诱导心肌细胞凋亡、引起线粒体膜电位下降和促进细胞色素C的释放。此外,缺氧能够显著下调态3呼吸和上调态4呼吸,引起呼吸控制率的下降,同时缺氧能够不同程度地下调线粒体呼吸链复合酶体Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ的蛋白表达水平。曲美他嗪能够显著降低缺氧诱导的心肌细胞凋亡、稳定线粒体膜电位和减少细胞色素C释放。此外,曲美他嗪还能减轻缺氧对线粒体呼吸链复合酶体的损伤,维持线粒体有氧呼吸。结论曲美他嗪具有抵抗缺氧致心肌细胞凋亡的作用,可能与其稳定线粒体膜和呼吸链复合酶体有关,继而减少细胞色素C的释放和维持线粒体有氧呼吸。     

PTD4-Cu/ZnSOD融合蛋白对缺氧复氧损伤模型大鼠心肌细胞H9C2心肌线粒体功能的影响

目的探讨蛋白质转导结构域4-铜锌超氧化物歧化酶(PTD4-Cu/ZnSOD)融合蛋白对缺氧/复氧损伤心肌线粒体功能的影响。方法 H9C2大鼠心肌细胞采用厌氧培养箱培养(85%N_2,10%H_2,5%CO_2)制作缺氧复氧损伤模型,之后在缺氧复氧损伤细胞培养液中不加任何处理因素作为HRI组,分别加入10μmol/L Cu/ZnSOD作为Cu/ZnSOD组、10μmol/L PTD4-Cu/ZnSOD作为PTD4-Cu/ZnSOD组,且以正常培养心肌细胞作为正常组。采用JC-1试剂盒检测线粒体膜电位,TUNEL法检测心肌细胞凋亡,生化测定心肌细胞线粒体三磷酸腺苷(ATP)酶活性、超氧化物歧化酶活性及丙二醛含量,Western blot检测心肌细胞线粒体B淋巴细胞瘤-2基因(Bcl-2)蛋白、Bax蛋白的表达。结果 HRI组线粒体膜电位显著低于正常组;PTD4-Cu/ZnSOD组线粒体膜电位较正常组较低。各处理组心肌细胞凋亡指数均明显高于正常组(P0.01);PTD4-Cu/ZnSOD组心肌细胞凋亡指数较HRI组明显降低(P0.01)。PTD4-Cu/ZnSOD组线粒体ATP酶活性明显高于HRI组,且超氧化物歧化酶活性较高,显著降低丙二醛含量(P0.01)。HRI组Bcl-2蛋白表达低于正常组,Bax蛋白表达高于正常组(P0.01);与HRI组比较,PTD4-Cu/ZnSOD融合蛋白能显著增加Bcl-2蛋白表达,降低Bax蛋白表达(P0.01)。结论 PTD4-Cu/ZnSOD融合蛋白可提高线粒体ATP酶活性,减轻线粒体损伤;提高线粒体SOD活性,减轻自由基对线粒体损伤;提高线粒体膜Bcl-2蛋白表达,降低Bax蛋白表达,从而发挥心肌保护作用。     

心房颤动犬能量代谢变化及曲美他嗪干预研究

目的 研究慢性心房颤动(房颤)犬心房能量代谢的变化,探讨曲美他嗪对房颤能量代谢和内皮功能的影响.方法 18只健康杂种犬,随机分为窦性心律组、心房起搏组和曲美他嗪组,每组6只犬.心房起搏组以400次/min快速起搏心房6周,建立房颤犬动物模型;曲美他嗪组给予曲美他嗪5 mg·kg-1·d-1口服,随后以400次/min快速起搏心房6周.采用高效液相色谱测定心肌组织磷酸肌酸(CrP)、三磷酸腺苷(ATP)、二磷酸腺苷(ADP)和一磷酸腺苷(AMP)含量,计算总腺苷酸池(TAN);用Western blot定量、免疫组化定性检测左房内皮型一氧化氮合酶(eNOS)蛋白表达,酶联免疫吸附定量检测血浆血管性血友病因子(vWF)含量,采用硝酸还原酶法测定血浆NO2-/NO3-(NOx)含量.结果 与窦性心律组相比,心房起搏6周后,心房肌CrP(P<0.01)和CrP/ATP(P<0.05)显著降低,而ATP、ADP、AMP和TAN无明显变化(P>0.05),内皮细胞功能标志物血浆vWF明显增高,NOx降低,心房eNOS蛋白表达减少.曲美他嗪治疗6周,心房肌CrP、CrP/ATP、ATP、ADP、AMP和TAN差异均无统计学意义,但eNOS蛋白表达上调(P<0.05),血浆vWF含量降低(P<0.01),NOx增加(P<0.05),内皮细胞功能改善.结论 房颤早期可出现能量代谢失衡,但随着持续时间延长,能量供求能重新达到平衡.曲美他嗪对房颤能量代谢无明显影响,但能通过一氧化氮途径改善内皮细胞功能.     

卡维地洛改善大鼠肥厚心肌能量代谢及其机制

目的探讨卡维地洛对压力超负荷大鼠肥厚心肌能量代谢的影响及其机制。方法将雄性SD大鼠随机分为假手术组、腹主动脉缩窄组和卡维地洛治疗组,15周后观察大鼠血流动力学参数、心室重构指标。采用密度梯度法提取大鼠心肌线粒体,用抑制剂终止法测定线粒体腺苷酸转运体（adenine nucleotide translocator,ANT）的转运活性,高效液相色谱法测量心肌组织及线粒体内腺苷酸含量。结果大鼠腹主动脉缩窄术后15周出现左心室肥厚及心功能减退;组织及线粒体内ATP、ADP及（ATP+ADP）含量及ANT转运活性降低。卡维地洛减轻心室肥厚、改善心功能的同时,增加组织及心肌线粒体腺苷酸含量,增强ANT转运活性。结论肥厚心肌心功能减退,心肌线粒体腺苷酸含量及ANT活性降低,使能量的产生和利用异常。卡维地洛改善心肌肥厚和心功能,且可能通过增强ANT活性而促进线粒体内产能,从而改善心肌能量代谢。     

Effect of captopril on myocardial energy metabolism in chronic pressure overload rats

Objective To investigate the effects of captopril on cardiac function and levels of energy-rich phosphates in pressure overload induced left ventricular hypertrophy rats. Methods One hundred and twenty SD rats were randomly divided into three groups: sham operation group (SH group, n=40),coarctation of abdominal aorta group (CAA group, n=40) and captopril treatment 1mg?100g-1?d-1) group (CAP group, n=40). Left ventricular end-diastolic pressure (LVEDP), left ventricular mass index (LVMI), levels of energy-rich phosphates and morphological changes of the myocardial mitochondria were compared at the 6th and 8th week after operation. Results At 6th week, in CAA group, LVMI and LVEDP were increased and ±dp/dtmax was decreased, while ATP and ADP were decreased and AMP was increased (P<0.01). These changes were much obvious at 8th week (P<0.01). Compared with those of CAA group, the parameters of heart function and energy-rich phosphates (ATP, ADP, AMP, TAN) in CAP group were improved significantly(P<0.01) at the 6th and 8th week. In CAP group, the parameters of heart function and energy-rich phosphates (ADP, AMP, TAN) were much better at 8th week than those at 6th week. The morphological change of mitochondria was less in CAP group than that in CAA group. Conclusion Captopril significantly improves myocardial energy metabolism in pressure overload rats and protects the function of myocardial mitochondria (J Geriatr Cardiol 2010; 7:176-179).     

Effects of hypobaric hypoxia on adenine nucleotide pools, adenine nucleotide transporter activity and protein expression in rat liver

AIM: To explore the effect of hypobaric hypoxia on mitochondrial energy metabolism in rat liver. METHODS: Adult male Wistar rats were exposed to a hypobaric chamber simulating 5000 m high altitude for 23 h every day for 0 (H0), 1 (H1), 5 (H5), 15 (H15) and 30 d (H30) respectively. Rats were sacrificed by decapitation and liver was removed. Liver mitochondria were isolated by differential centrifugation program. The size of adenine nucleotide pool (ATP, ADP, and AMP) in tissue and mitochondria was separated and measured by high performance liquid chromatography (HPLC). The adenine nucleotide transporter (ANT) activity was determined by isotopic technique. The ANT total protein level was determined by Western blot. RESULTS: Compared with H0 group, intra-mitochondrial ATP content decreased in all hypoxia groups. However, the H5 group reached the lowest point (70.6%) (P<0.01) when compared to the control group. Intra-mitochondrial ADP and AMP level showed similar change in all hypoxia groups and were significantly lower than that in H0 group. In addition, extra-mitochondrial ATP and ADP content decreased significantly in all hypoxia groups. Furthermore, extra-mitochondrial AMP in groups H5, H15 and H30 was significantly lower than that in H0 group, whereas H1 group had no marked change compared to the control situation. The activity of ANT in hypoxia groups decreased significantly, which was the lowest in H5 group (55.7%) (P<0.01) when compared to H0 group. ANT activity in H30 group was higher than in H15 group, but still lower than that in H0 group. ANT protein level in H5, H15, H30 groups, compared with H0 group decreased significantly, which in H5 group was the lowest, being 27.1% of that in HO group (P<0.01). ANT protein level in H30 group was higher than in H15 group, but still lower than in HO group. CONCLUSION: Hypobaric hypoxia decreases the mitochondrial ATP content in rat liver, while mitochondrial ATP level recovers during long-term hypoxia exposure. The lower level of extra-mitochondrial ATP may be related to the decrease of ANT activity during hypoxia exposure.     

曲美他嗪对慢性心力衰竭大鼠心肌能量代谢及超微结构的影响

目的研究曲美他嗪对异丙肾上腺素诱导的慢性心力衰竭大鼠心肌能量代谢和超微结构的影响。方法72只雄性SD大鼠随机分为对照组(14只)和模型组(58只),模型制备采用皮下多点注射异丙肾上腺素法,4周后模型组大鼠死亡12只,再将存活的46只模型组大鼠随机分为未治疗组(M组,16只)、曲美他嗪治疗组(T组,15只)和培哚普利治疗组(P组,15只)。治疗5周后行二维心脏超声检查和病理形态学观察,并测定心肌组织能量代谢相关指标。结果与M组比较,T组大鼠LVEF、左心室短轴缩短率均提高;光镜和电镜下观察T组和P组心肌损伤程度较M组明显减轻。T组与P组大鼠心肌二磷酸腺苷(ADP)、一磷酸腺苷、ATP/ADP和总腺苷含量与对照组比较差异无统计学意义(P>0.05)。T组大鼠心肌肌浆网Ca2+-ATPase活性与对照组和P组比较差异无统计学意义。结论曲美他嗪能够改善心力衰竭大鼠心肌能量代谢、病理和超微结构,并且有改善大鼠心功能的趋势。     

Mst1敲除减轻高脂饮食诱发的心肌线粒体动力学紊乱

目的 探讨哺乳动物STE20样激酶1（Mst1）基因敲除是否可以减轻高脂饮食导致的心肌线粒体动力学紊乱并探究其机制。 方法 C57BL/6小鼠（WT）和Mst1基因敲除小鼠（Mst1-/-）(C57BL/6背景)随机分为正常饮食（Normal diet,ND）组和高脂饮食（High-fat diet,HFD）组,连续喂养16w后,检测各组小鼠体质量、心脏重量/胫骨长度和空腹血脂水平,超声心动图评估心脏功能,HE染色及透射电镜观察心肌肥厚和线粒体形态,心肌柠檬酸合酶(CS)活性和ATP含量评价线粒体功能,Western blot检测线粒体动力学相关蛋白的表达水平。 结果 与ND+WT组相比,HFD+WT组小鼠出现肥胖、高血脂、心肌肥厚和心脏舒张功能障碍,同时线粒体分裂增多、形态明显受损,心肌CS活性、ATP含量均降低,线粒体分裂蛋白Drp1、Fis1的表达明显上调（P<0.05）,融合蛋白Mfn2的表达明显下调（P<0.05）;与HFD+WT组相比,HFD+Mst1-/-组小鼠心脏舒张功能、线粒体形态与功能的损伤明显减轻,Drp1表达明显下调（P<0.05）,Mfn2表达明显上调（P<0.05）。 结论 Mst1基因敲除可以通过抑制线粒体分裂,促进线粒体融合,以维持线粒体动力学稳定,从而减轻脂毒性相关心肌损害。     

Effect of captopril on myocardial energy metabolism in chronic pressure overload rats

Objective To investigate the effects of captopril on cardiac function and levels of energy-rich phosphates in pressure overload induced left ventricular hypertrophy rats. Methods One hundred and twenty SD rats were randomly divided into three groups： sham operation group （SH group, n=40）,coarctation of abdominal aorta group （CAA group, n=40） and captopril treatment lmg~ 100g1 ~ d-1） group （CAP group, n=40）. Left ventricular end-diastolic pressure （LVEDP）, left venh-icular mass index （LVMI）, levels of energy-rich phosphates and morphological changes of the myocardial mitochondria were compared at the 62 and 82 week after operation. Results At 62 week, in CAA group, LVMI and LVEDP were increased and _ dp/dtmax was decreased, while ATP and ADP were decreased and AMP was increased （P〈0.01）. These changes were much obvious at 8th week （P〈0.01）. Compared with those of CAA group, the parameters of heart function and energy-rich phosphates （ATP, ADP, AMP, TAN） in CAP group were improved significantly（P〈0.01） at the 6th and 8th week. In CAP group, the parameters of heart function and energy-rich phosphates （ADP, AMP, TAN） were much better at 8~ week than those at 6th week. The morphological change of mitochondria was less in CAP group than that in CAA group. Conclusion Captopril significantly improves myocardial energy metabolism in pressure overload rats and protects the function of myocardial mitochondria     

Myocardial fuel and energy balance, acute ischemia and diabetes

When glucose-insulin-potassium (GIK) is infused, glucose supplies most of the energy demands of the heart. Fatty acid becomes the major substrate during fasting, pathologically increased work loads or insulin deficiency. Myocardial purine breakdown reflects myocardial energy status and influences coronary tone. Ischemia accelerates breakdown of ATP to AMP, which is further metabolized to adenosine, which causes vasodilatation and a blunted response to catecholamines. If normal circulation is restored, ADP and AMP are rapidly converted to ATP and purine metabolism is changed from degradation to salvage and de novo synthesis of purines. Ischemia impairs mitochondrial function, causing decreased capacity to oxidize fatty acids once aerobic conditions return. Thus, reperfusion with elevated plasma free fatty acids results in acyl-CoA accumulation in the heart. In diabetic animals, phosphorylation of AMP to ATP is defective in the heart, and AMP degradation is increased. Therefore, careful regulation of the blood sugar with concomitant lowering of plasma free fatty acids in diabetics with ischemic heart disease should improve myocardial salvage by preserving and repleting myocardial ATP. Thus, along with reestablishment of coronary flow and reduction in myocardial oxygen demands, may significantly reduce the morbidity of acute ischemia in diabetics.     

Energy stores and metabolites in chronic reversibly and irreversibly dysfunctional myocardium in humans

OBJECTIVES: Our goal was to study metabolic energy stores and lactate content in chronic reversibly and irreversibly dysfunctional myocardium. BACKGROUND: It is unknown whether metabolism is deranged in chronic reversibly and irreversibly dysfunctional myocardium in humans. Semiquantitative histological examinations have shown altered mitochondrial morphology and glycogen accumulation in dysfunctional regions. METHODS: We studied 25 patients with a mean ejection fraction of 38 +/- 9% scheduled for coronary artery bypass surgery. Regional perfusion and metabolism were assessed by positron emission tomography, and regional function was assessed by echocardiography. Perioperative myocardial biopsies were obtained from a control region and from a dysfunctional region. We analyzed biopsies for contents of noncollagen protein (NCP), ATP, ADP, AMP, glycogen and lactate. Six months after surgery we assessed wall motion by echocardiography to group patients in those with (n = 11) and without (n = 14) functional improvement. RESULTS: Reversibly dysfunctional myocardium had reduced perfusion (0.59 +/- 0.16 vs. 0.69 +/- 0.20 ml/g/min, p < 0.05), similar glucose-tracer uptake (92 +/- 12 and 95 +/- 14%), ATP/ADP ratio (2.4 +/- 1.1 and 2.4 +/- 0.7), glycogen content (631 +/- 174 and 632 +/- 148 nmol/microg NCP) and lactate levels (59 +/- 27 and 52 +/- 29 nmol/microg NCP) compared with control regions. Irreversibly dysfunctional regions (n = 14) had severely reduced perfusion (0.48 +/- 0.15 vs. 0.72 +/- 0.12 ml/g/min, p < 0.001) and glucose-tracer uptake (52 +/- 16 vs. 94 +/- 15%, p < 0.001), reduced ATP/ADP ratio (1.5 +/- 0.9 vs. 2.3 +/- 0.9, p < 0.05), similar glycogen content (579 +/- 265 vs. 593 +/- 127 nmol/microg NCP) and increased lactate levels (114 +/- 52 vs. 89 +/- 24 nmol/microg NCP, p < 0.01) compared with control regions. CONCLUSIONS: Contents of metabolic energy stores and lactate in chronic reversibly dysfunctional myocardium were preserved. In contrast, energy stores were depleted in myocardium without functional recovery after revascularization.