脂联素与代谢综合征的研究进展
2.4 脂联素与血脂代谢紊乱
血脂代谢紊乱以高水平三酰甘油（TG）、高水平低密度脂蛋白(LDL)和低水平高密度脂蛋白(HDL)为特征。调节血脂代谢在预防心血管疾病危险的发生中有积极作用。脂联素连接着脂肪组织和整体代谢，在能量的平衡、控制方面起到重要的作用。在骨骼肌和肝脏中脂联素通过激活AMPK途径而刺激葡萄糖的利用，同时也激活了磷酸酰基辅酶A碳酸酶，增加了脂肪酸的氧化，降低了循环和组织中的游离脂肪酸水平。多项研究显示，血浆脂联素水平与TG、LDLC、HDLC独立相关。2型糖尿病患者中，校正了BMI、年龄和血压后,血浆脂联素水平与TG、apoB、LDLC呈负相关,与HDLC、apoA呈正相关。脂联素可以增加脂肪酸氧化，降低肌肉与肝脏中的TG含量，改善脂代谢，发挥抗动脉粥样硬化的作用。
2.5 其他
代谢综合征患者发生心血管疾病的风险要比正常人高许多，同时近年研究发现这类患者中多数伴有脂联素水平的降低，使得脂联素与心血管疾病的关系日益受到重视。在冠心病的发生中基本病理改变是动脉粥样硬化，而动脉粥样硬化是一种慢性炎性疾病，在这一发病过程中，内皮细胞、平滑肌细胞、巨噬细胞是构成动脉病变的3个要素。大量体外研究证实，脂联素抑制巨噬细胞清道夫受体A的表达，降低其摄取氧化型低密度脂蛋白的能力，从而抑制其向泡沫细胞的转化；抑制动脉血管内皮细胞、血管平滑肌细胞的增殖、分化及向内皮下损伤区的迁徙，从而抑制动脉粥样硬化灶的形成而直接发挥血管保护作用。近年来，研究发现脂联素和心肌肥厚疾病直接相关。Shibata［23］等报道，脂联素基因敲除的高血压模型小鼠，心肌肥厚的发病率增高且病死率高。这可能与脂联素激活AMPK途径的减弱有关。体外实验表明，脂联素可激活培养心肌细胞的AMPK途径并对抗激动剂激动的心肌肥厚。结果表明，与其他脂肪细胞因子不同，脂联素可通过激活AMPK途径抑制心肌细胞肥厚，具有保护心肌细胞的作用。
3 展望
脂联素通过与其受体如Adipo R1和Adipo R2的结合，激活特定信号转导通路，改善代谢综合征患者的糖脂代谢并调控其并发症的发生发展过程。因此，通过监测血清脂联素水平，有利于对代谢综合症各种因子风险的评估，尽可能早期进行干预治疗，改善预后。
将来人们可以直接用脂联素作为抗肥胖药、2型糖尿病的一级预防药物及其并发症的二级预防药物，也可开发促进内源性脂联素分泌的代谢综合征的防治药物，例如TZD。因此,对脂联素的分子结构、影响脂联素分泌表达的因素及脂联素受体的信号转导进行深入研究,提高体内脂联素水平，将为代谢综合征的防治提供一条新的途径。
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