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1、DISORDERSOFLIPIDMETABOLISMDepartmentofLaboratoryMedicineWestChinaMedicalSchoolSichuanUniversity李萍(LIPing)一、PlasmaLipoprotein二、DisordersofLipoproteinMetabolism三、AnalysisAssay四、Caseanalysis一、PlasmaLipoprotein分類(classification)?根據(jù)化學(xué)結(jié)構(gòu)將血漿脂肪分為膽固醇(cholesterol),甘油三酯(triglyceride),磷脂(phospholipid)和游離
2、脂肪酸(freelipid)。脂肪在血漿中以脂蛋白型式存在,所以高脂血癥一定是高脂蛋白血癥(hyperlipoproteinemia)。分類(classification)?根據(jù)化學(xué)結(jié)構(gòu),脂蛋白電泳或超速離心對血漿脂蛋白進行分類。主要的脂蛋白有高密度脂蛋白(HDL),低密度脂蛋白(LDL),極低密度脂蛋白(VLDL)和乳糜微粒(CM)。血漿脂蛋白分析可有助于明確病因。超速離心CMVLDLLDLHDL電泳CM前β-LPβ-LPα-LP?膽固醇主要存在于HDL和LDL中,而甘油三酯主要存在于VLDL和乳糜微粒中。不同的基因缺陷可能產(chǎn)生同樣的脂蛋白異常,只有通過廣泛的家族分析予以鑒別。T
3、hefourmainlipoproteinsandtheirfunctionsLiporoteinMainapoliporoteinsFunctionCMB48,A-I,C-II,ELargestlipoprotein.Synthesizedbygutafterameal.Notpresentinnormalfastingplasma.MaincarrierofdietarytriglycerideVLDLB100,C-II,ESynthesizedintheliver.MaincarrierofendogenouslyproducedtriglycerideLDLB100Gene
4、ratedfromVLDLinthecirculationMaincarrierofcholesterolHDLA-I,A-IISmallestbutmostabundant.Protectivefunction.Takescholesterolfromextrahepatictissuestotheliverforexcretion脂蛋白代謝(Lipoproteinmetabolism)脂蛋白的代謝是以肝臟為中心通過兩個循環(huán)進行內(nèi)源性外源性(endogenous)(exogenous)兩個關(guān)鍵酶:脂蛋白脂酶(Lipoproteinlipase,LPL):從CM和VLDL中解離出脂
5、肪酸和甘油至組織卵磷脂膽固醇?;D(zhuǎn)移酶(Lecithincholesterolacyltransferase,LCAT):使游離膽固醇和脂肪酸形成膽固醇酯LDLReceptorPathwayLDL受體途徑主要功能:通過攝取膽固醇進入細胞內(nèi),用于細胞增殖和類固醇激素及膽汁酸鹽的合成等。LipoproteinMetabolism(summary)LipoproteinarecomplexesoflipidandproteinswhichfacilitatelipidtransportTheirmetabolismcanbethoughtofastwointerconnectedcycl
6、escenteredontheliverLipoproteinsaredefinedbytheirdensityanddifferincomposition,structureandfunctionApolipoproteinshaveafunctionalaswellasstructuralimportanceCholesterolcanonlybeexcretedfromthebodybywayoftheliver.二、DisordersofLipoproteinMetabolismLipoproteindisordersaresomeofthecommonestmetabol
7、icdiseasesseeninclinicalpractice.Theymaypresentwiththeirvarioussequelaewhichinclude:coronaryheartdisease,CHDacutepancreatitisfailuretothriveandweaknesscataractsClassificationGenaticPathogenyPrimary--whenthedisorderisnotduetoanidentifiab