Bismuth Jean, Chai Hong, Lin Peter H, Yao Qizhi, Chen Changyi
Molecular Surgeon Research Center, Division of Vascular Surgery and Endovascular Therapy, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA.
Med Sci Monit. 2009 Sep;15(9):BR270-4.
Lactosylceramide (LacCer) is a member of the glycosphingolipid family, which has been implicated in the atherogenic process. The goal of this study was to determine the effects and molecular mechanisms of LacCer on endothelial functions in porcine coronary arteries and human coronary endothelial cells (HCAECs).
MATERIAL/METHODS: The vessel rings and HCAECs were treated with different concentrations of LacCer for 24 hours. Vasomotor function was studied using a myograph tension system in response to thromboxane A2 analog U46619, bradykinin and sodium nitroprusside (SNP). Superoxide anion production was determined using lucigenin-enhanced chemiluminescence. The expression of endothelial nitric oxide synthase (eNOS), NADPH oxidase subunit NOX4 and catalase was determined by real-time PCR.
LacCer (0.1, 1 and 10 microM) significantly decreased endothelium-dependent vasorelaxation (bradykinin) in porcine coronary artery rings in a concentration-dependent manner compared with untreated controls (P<0.05). High concentration of LacCer (10 microM) also reduced endothelium-independent vasorelaxation (SNP). However, LacCer did not affect vessel contraction (U46619). Antioxidant selenomethionine (SeMet) effectively reversed LacCer-induced endothelial dysfunction in the vessel rings. Furthermore, LacCer significantly increased superoxide anion production in the vessel rings in a concentration-dependent manner compared with untreated controls (P<0.05). In response to LacCer treatment, NOX4 mRNA levels were significantly increased, while the expression of catalase and eNOS was significantly decreased in HCAECs compared with controls (P<0.05).
LacCer causes endothelial dysfunction with potential mechanisms of the down-regulation of eNOS and increase of oxidative stress due to the activation of NADPH oxidase and inhibition of internal antioxidant catalase. This study suggests that LacCer may represent a risk factor to the vascular system and antioxidant SeMet may have clinical applications for prevention of vascular disease.
乳糖神经酰胺（LacCer）是糖鞘脂家族的一员，与动脉粥样硬化形成过程有关。本研究的目的是确定LacCer对猪冠状动脉和人冠状动脉内皮细胞（HCAECs）内皮功能的影响及其分子机制。
材料/方法：用不同浓度的LacCer处理血管环和HCAECs 24小时。使用肌张力测定系统研究血管舒张功能，以响应血栓素A2类似物U46619、缓激肽和硝普钠（SNP）。使用光泽精增强化学发光法测定超氧阴离子的产生。通过实时PCR测定内皮型一氧化氮合酶（eNOS）、NADPH氧化酶亚基NOX4和过氧化氢酶的表达。
与未处理的对照组相比，LacCer（0.1、1和10微摩尔）以浓度依赖的方式显著降低猪冠状动脉环中内皮依赖性血管舒张（缓激肽）（P<0.05）。高浓度的LacCer（10微摩尔）也降低了非内皮依赖性血管舒张（SNP）。然而，LacCer不影响血管收缩（U46619）。抗氧化剂硒代蛋氨酸（SeMet）有效地逆转了LacCer诱导的血管环内皮功能障碍。此外，与未处理的对照组相比，LacCer以浓度依赖的方式显著增加了血管环中超氧阴离子的产生（P<0.05）。与对照组相比，在HCAECs中，响应LacCer处理，NOX4 mRNA水平显著增加，而过氧化氢酶和eNOS的表达显著降低（P<0.05）。
LacCer导致内皮功能障碍，其潜在机制是eNOS下调以及由于NADPH氧化酶激活和内源性抗氧化剂过氧化氢酶抑制导致氧化应激增加。本研究表明，LacCer可能是血管系统的一个危险因素，抗氧化剂SeMet可能在预防血管疾病方面具有临床应用价值。
