A PUFA Dietary Intervention for Heart Rate

PUFA 饮食干预心率

• 批准号: 8335786
• 负责人: Edward Lakatta
• 金额: $ 25.83万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8335786
• 关键词: 4 hydroxynonenal; Acids; Affect; Affinity; Age; Alzheimer' s Disease; Aorta; Arrhythmia; Calcium; Cardiac; Cardiolipins; Cardiovascular system; Cells; Ceramides; Cessation of life; Chemistry; Cholesterol; Clinical; Data; Data Analyses; Diet; Dietary Intervention; Disease; Elderly; Epidemiologic Studies; Epidemiology; Esters; Event; Fatty Acid Desaturases; Fatty Acids; Fatty acid glycerol esters; Fish Oils; Fishes; Gangliosides; Gas Chromatography; Heart Atrium; Heart Rate; Homeostasis; Image; Individual; Industry; Ion Channel; Ions; Link; Lipid Peroxidation; Lipids; Membrane; Membrane Lipids; Membrane Microdomains; Methodology; Modeling; Mole the mammal; Nerve; Nodal; Nonesterified Fatty Acids; Omega-3 Fatty Acids; Oryctolagus cuniculus; Outcome; Outcome Study; Oxidation-Reduction; Pacemakers; Pharmaceutical Preparations; Polyunsaturated Fatty Acids; Property; Proteins; Protocols documentation; Rattus; Residual state; Rest; Rodent; Sarcoplasmic Reticulum; Signal Transduction; Signaling Molecule; Signaling Protein; Sinoatrial Node; Skin; Sphingomyelins; Surface; Tissues; Ultracentrifugation; Ventricular; Ventricular Fibrillation; age related; arm; normal aging; novel; patch clamp

We, and others, have demonstrated that dietary content of long chain polyunsaturated fatty acids (PUFA) affects their incorporation into cell membrane lipid rafts. PUFA have a dramatic impact on cell ion homeostasis and redox chemistry. Omega 3 PUFA, the good variety of PUFA, type typified by Docosohexanoic acid, protect from lethal post-ischemic arrhythmias, whilst the Omega 6, the bad variety of PUFA, promote theses arrhythmias. With advancing age in rodents, membrane Omega 3 decrease and Omega 6 increase. Old rats are extremely vulnerable to post ischemic ventricular fibrillation. The age-associated change in membrane PUFA profile is completely reversed by diets rich in Omega 3 PUFA, as is the vulnerability to ventricular fibrillation. Accumulating epidemiological evidence indicates that dietary PUFA (from fish) confer secondary protection from death due to cardiovascular events related to Alzheimers CV disease. In these studies, it was noted that those individuals who consumed diets high in Omega 3 PUFA also had a reduction in resting heart rate. Numerous other recent epidemiological studies have demonstrated a beneficial effect to a lower (but normal) heart rate with respect to morbid outcomes with CV disease. The Pharma industry has begun to capitalize upon these discoveries by initiating clinical outcome studies to reduce heart rate using bradycardic drug as the active arm. Results to date demonstrate that there is a moderate, but significant reduction in baseline and intrinsic (elimination of sympathetic and residual nerve control) heart rate following a 40-60 day diet of Omega 3 PUFA compared to a diet of Omega 6 PUFA. Analysis of data is ongoing for studies employed to identify mechanistic causes for altered beating rates in isolated sinoatrial nodal cells between the two dietary groups: 1) patch clamp protocols to evaluate their beating rate and also possible changes in some other electrophysiological parameters, 2) skinned cell methodologies to compare local calcium release (LCR) and sarcoplasmic reticulum (SR) load, and 3) cytosolic Ca2+ transients. The large amount of cardiac tissue collected is being analyzed for fatty acid content and incorporation. Gas chromatography of fatty acid methyl ester extracted from the ventricle, sinoatrial node, atria and aorta revealed overall increases in membrane n-3 PUFA in fish oil diet versus control diet. Mole to mole (Omega-3/Omega-6) ratios of the two most biologically active Omega-3 PUFAs DHA and EPA were found in ranges of all fish oil tissues from 3:1 to 31:1. Specifically, the affinity for n-3 EPA was found to be the highest in the sinoatrial node at 31:1 followed by the atria 29:1, aorta 27:1 and ventricle 3:1. The aorta showed the highest affinity for DHA at 21:1 followed by the ventricle 13:1, atria 15:1 and the sinoatrial node 8:1. Total Omega-3 fatty acids comprised 15% of total lipids in fish oil diets 2% in control diets. Also, there was an increase in incorporation of Omega-3 PUFA proportionate to the number of days on the fish oil diet. These data indicate an important cardiovascular tissue specific incorporation of dietary PUFA . To further elucidate signaling membrane changes, rabbit tissues were pooled (n=5) then fractionated through ultracentrifugation to isolate lipid rafts. These fractions were then extracted for protein or lipid analysis. Preliminary lipid analysis indicates that the PUFA diet significantly shifts lipid raft components (i.e. sphingomyelins, ceramides, gangliosides, and cholesterol, cardiolipin) that normally increase with age and/or a high fat (Omega-6) diet. These changes were also accompanied by decreases in lipid peroxidation markers 4-hydroxynonenal and 8-epi-prostaglanin F2. We also observed significant increases in the ratio of unsaturated free fatty acids (C16:1 and C24:1) which are indicative of PUFA inhibition of fatty acid desaturase. All of these effects seem to reverse the normal age-related changes seen in these lipid profiles, and helps explain many of the beneficial effects of a high PUFA diet.

我们和其他人已经证明，膳食中长链多不饱和脂肪酸（PUFA）的含量会影响其进入细胞膜脂筏。PUFA对细胞离子稳态和氧化还原化学具有显著影响。欧米茄3多不饱和脂肪酸，多不饱和脂肪酸的良好品种，二十二碳六烯酸的典型类型，防止致命的缺血后心律失常，而欧米茄6，多不饱和脂肪酸的坏品种，促进这些心律失常。随着年龄的增长，膜Omega 3减少，Omega 6增加。老年大鼠极易发生缺血后心室颤动。与年龄相关的膜PUFA分布的变化被富含Omega 3 PUFA的饮食完全逆转，心室纤颤的脆弱性也是如此。 越来越多的流行病学证据表明，饮食中的PUFA（来自鱼类）可提供二级保护，使患者免于因与阿尔茨海默病相关的心血管事件而死亡。在这些研究中，人们注意到，那些食用富含Omega 3 PUFA的饮食的人也会降低静息心率。最近的许多其他流行病学研究已经证明了较低（但正常）心率对CV疾病的病态结局的有益作用。制药行业已经开始利用这些发现，启动临床结果研究，以降低心率使用心动过缓药物作为积极的手臂。 迄今为止的结果表明，与Omega 6 PUFA饮食相比，Omega 3 PUFA饮食40 - 60天后基线和内在（交感神经和残余神经控制的消除）心率中度但显著降低。 正在进行数据分析，以确定两个饮食组之间孤立窦房结细胞搏动率改变的机械原因：1）膜片钳方案，以评估它们的搏动速率以及一些其他电生理参数的可能变化，2）皮肤细胞方法学，以比较局部钙释放（LCR）和肌浆网（SR）负荷，3）胞浆Ca~（2+）瞬变。收集的大量心脏组织正在分析脂肪酸含量和掺入。 从心室、窦房结、心房和主动脉中提取的脂肪酸甲酯的气相色谱显示，鱼油饮食与对照饮食相比，膜n-3 PUFA总体增加。在所有鱼油组织中，发现两种最具生物活性的ω-3多不饱和脂肪酸DHA和EPA的摩尔比（ω-3/ω-6）在3：1至31：1之间。具体地，发现对n-3EPA的亲和力在窦房结中最高，为31：1，其次是心房29：1，主动脉27：1和心室3：1。主动脉显示出对DHA的最高亲和力，为21：1，随后是心室13：1，心房15：1和窦房结8：1。总欧米茄-3脂肪酸占鱼油饮食中总脂质的15%，占对照饮食中的2%。此外，Omega-3 PUFA的掺入量与鱼油饮食的天数成比例增加。这些数据表明，一个重要的心血管组织特异性纳入膳食PUFA。 为了进一步阐明信号传导膜的变化，将兔组织合并（n = 5），然后通过超离心分离以分离脂筏。 然后提取这些级分用于蛋白质或脂质分析。 初步脂质分析表明，PUFA饮食显著改变了脂筏组分（即鞘磷脂、神经酰胺、神经节苷脂和胆固醇、心磷脂），这些组分通常随着年龄和/或高脂肪（Omega-6）饮食而增加。 这些变化还伴随着脂质过氧化标记物4-羟基壬烯醛和8-表-异丙肾上腺素F2的减少。 我们还观察到不饱和游离脂肪酸（C16：1和C24：1）的比率显著增加，这表明PUFA抑制脂肪酸去饱和酶。 所有这些影响似乎都逆转了这些脂质分布中与年龄相关的正常变化，并有助于解释高PUFA饮食的许多有益作用。