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，长链多不饱和脂肪酸（PUFA）的膳食含量会影响它们融入细胞膜脂筏中。 PUFA 对细胞离子稳态和氧化还原化学具有巨大影响。 Omega 3 PUFA 是 PUFA 的优良品种，以二十二碳六烯酸为代表，可以预防致命性缺血后心律失常，而 Omega 6 是 PUFA 的不良品种，可促进这些心律失常。随着啮齿动物年龄的增长，膜上的 Omega 3 含量减少，而 Omega 6 含量增加。老年大鼠极易发生缺血后心室颤动。富含 Omega 3 PUFA 的饮食可以完全逆转膜 PUFA 谱与年龄相关的变化，以及心室颤动的脆弱性。 越来越多的流行病学证据表明，饮食中的多不饱和脂肪酸（来自鱼类）可提供二级保护，防止因与阿尔茨海默病相关的心血管事件而导致死亡。在这些研究中，人们注意到那些食用富含 Omega 3 PUFA 的饮食的人的静息心率也会降低。最近的许多其他流行病学研究已经证明，较低（但正常）的心率对于心血管疾病的病态结果具有有益的作用。制药行业已开始利用这些发现，启动临床结果研究，以使用心动过缓药物作为活性药物来降低心率。 迄今为止的结果表明，与欧米伽 6 PUFA 饮食相比，欧米伽 3 PUFA 饮食 40-60 天后，基线心率和内在心率（消除交感神经和残余神经控制）心率有中度但显着的降低。 正在进行数据分析，用于确定两个饮食组之间孤立窦房结细胞搏动率改变的机制原因：1）膜片钳方案评估其搏动率以及其他一些电生理参数的可能变化，2）剥皮细胞方法学比较局部钙释放（LCR）和肌浆网（SR）负荷，以及3）胞质Ca2+ 瞬变。正在分析收集的大量心脏组织的脂肪酸含量和掺入情况。 从心室、窦房结、心房和主动脉提取的脂肪酸甲酯的气相色谱分析显示，与对照饮食相比，鱼油饮食中膜 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 Omega-3 PUFA DHA 和 EPA 的摩尔与摩尔 (Omega-3/Omega-6) 比率为 3:1 至 31:1。具体来说，发现窦房结中 n-3 EPA 的亲和力最高，为 31:1，其次是心房 29:1、主动脉 27:1 和心室 3:1。主动脉对 DHA 的亲和力最高，为 21:1，其次是心室 13:1、心房 15:1 和窦房结 8:1。总 Omega-3 脂肪酸占鱼油日粮中总脂质的 15%，对照日粮中的 2%。此外，Omega-3 PUFA 的摄入量也随着鱼油饮食天数的增加而增加。这些数据表明饮食中 PUFA 的特殊掺入对心血管组织具有重要意义。 为了进一步阐明信号膜的变化，汇集兔组织（n=5），然后通过超速离心进行分级以分离脂筏。 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 饮食显着改变了通常随着年龄和/或高脂肪 (Omega-6) 饮食而增加的脂筏成分（即鞘磷脂、神经酰胺、神经节苷脂和胆固醇、心磷脂）。 这些变化还伴随着脂质过氧化标记物 4-羟基壬烯醛和 8-表前列腺素 F2 的减少。 我们还观察到不饱和游离脂肪酸（C16:1 和 C24:1）的比例显着增加，这表明 PUFA 对脂肪酸去饱和酶的抑制作用。 所有这些效应似乎都逆转了血脂谱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。