ENDOTHELIAL CELLS PREVENT ACCUMULATION OF LIPID HYDROPEROXIDES IN LDL

内皮细胞防止低密度脂蛋白中脂质过氧化氢的积累

• 批准号: 6307896
• 负责人: DAVID M SMALLEY
• 金额: $ 1.13万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2001-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6307896
• 关键词: animal tissue; bioengineering /biomedical engineering; biomedical resource; lipids

A variety of cell types, including endothelial cells, oxidize low-density lipoprotein (LDL). To investigate the mechanisms by which endothelial cells modulate LDL oxidation states, endothelial cell cultures were incubated with LDL (240 mg cholesterol/dL) for 24 h in M199 supplemented with fetal bovine serum (FBS, 16.7%). These conditions were not toxic to endothelial cells over the time frame of the study. Changes in LDL oxidation were monitored by measuring thiobarbituric acid-reactive substances (TBARS), lipid hydroperoxide (LOOH), and conjugated dienes. LDL medium incubated in the absence of endothelial cells contained higher TBARS that did LDL medium incubated with endothelial cells. LOOHs were higher in LDL medium incubated without endothelial cells than in LDL medium incubated with endothelial cells. Conjugated diene formation, based on changes in absorbance at 234 nm, increased to a greater extent in LDL medium incubated in the absence of endothelial cells than when endothelial cells were present. To increase oxidative stress on the endothelial cell cultures, increasing concentrations of Cu(2+) (0 to 4 micromole) were added to LDL medium. Endothelial cells prevented LOOH accumulation until the concentration of Cu(2+) exceeded 0.75 micromole. AT 1.5 and 4 micromole Cu(2+), endothelial cells enhanced LOOH formation nearly 3 and 2.5 times the LOOH values in the corresponding medium incubated in the absence of endothelial cells. This loss of protective function, however, was not permanent. Endothelial cells, preincubated for 24 h with Cu(2+)-containing LDL medium, were still able to prevent LOOH accumulation in fresh LDL medium. Endothelial cells prevented LOOH accumulation even when exposed to LDL medium that contained low concentrations of LOOHs (<22 nmol/mg). However, endothelial cells accelerated the accumulation of LOOHs in LDL when exposed to LDL medium that contained slightly higher concentrations of preexisting LOOHs (about 33 nmol/ng). These data indicate that endothelial cells have a limited capacity for preventing LOOH formation and that small increases in LOOHs may play a critical role in enhancing the potential of endothelial cells for oxidative modification of LDL.

多种细胞类型，包括内皮细胞， 低密度脂蛋白（LDL）。 为了研究 内皮细胞调节LDL氧化状态，内皮细胞 将培养物与LDL（240 mg胆固醇/dL）在100 ml/min的培养液中孵育24小时。 补充有胎牛血清（FBS，16.7%）的M199。 这些 条件是没有毒性的内皮细胞在时间范围内， 书房 LDL氧化的变化通过测量 硫代巴比妥酸反应物质（TBARS），脂质过氧化氢 （LOOH）和共轭二烯。 LDL培养基在不存在 内皮细胞含有更高的TBARS，LDL培养基孵育 内皮细胞。 在LDL培养基中孵育的LOOH较高， 与在LDL培养基中孵育的内皮细胞相比， 内皮细胞 共轭二烯的形成，基于 234 nm处的吸光度，在LDL培养基中增加到更大程度 在没有内皮细胞的情况下孵育， 细胞存在。 增加内皮细胞的氧化应激 细胞培养，增加Cu（2+）浓度（0至4微摩尔） 加入LDL培养基中。 内皮细胞阻止LOOH Cu（2+）浓度超过0.75 微摩尔 在1.5和4微摩尔Cu（2+）时，内皮细胞增强 LOOH的形成几乎是LOOH值的3和2.5倍， 在不存在内皮细胞的情况下孵育相应的培养基。 然而，这种保护功能的丧失并不是永久性的。 内皮细胞，用含Cu（2+）的LDL预孵育24 h 仍然能够防止新鲜LDL中LOOH的积累 介质 内皮细胞阻止LOOH积累，即使 暴露于含有低浓度LOOH（<22 nmol/mg）。 然而，内皮细胞加速了 当暴露于LDL培养基时， 预先存在的LOOH浓度（约33 nmol/ng）。 这些数据 表明内皮细胞具有有限的预防能力， LOOH的形成，LOOH的小幅增加可能会对 在增强内皮细胞氧化能力中的作用 修饰LDL。