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LIPOPROTEINE

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Structura lipoproteinelor

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LIPOPROTEINELE

HDL-Colesterol(High-density lipoprotein)

LDL-Colesterol (Low-density lipoprotein)

VLDL-Colesterol (Very low density lipoprotein)

Chilomicroni

Fiecare clas de lipoproteine are dimensiune, structur(compoziie de lipide i apolipoproteine) ifunciediferit.

Cu ct raportul proteine-lipide este mai mic, cu attdensitatea este mai mic.

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CHILOMICRONII

1.nveli de apolipoproteine

2. Nucleu : - 97% trigliceride

- 3 % esteri de colesterol.

LPL

Intestinal Limfatic Plasm Chi

remnants

Chi remnantsendocitai hepatic.

LPL - lipoprotein lipaza

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VLDL - COLESTEROL1.nveli de apolipoproteine

2. Nucleu - 75% trigliceride

- 25% esteri de colesterol.

LPL

Hepatic Plasma IDL (intermediate deansity

lipoproteins)

HL

IDL : - endocitat hepatic LDL

- se tranform n LDL.

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LDL COLESTEROL

IDL apolipoproteine- trigliceridele rmase n urma hidrolizei VLDL- esterii de colesterol din VLDL.

Trigliceride

IDL HDL 2

Esteri de colesterol

LDL- colesterol.

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LDL-colesterol

1. nveli - apolipoproteine.2. Nucleu : - 88% esteri de colesterol

- 12% trigliceride.

La nivelul celulelor nucleate exist receptoriipentru LDL (70% la nivelul hepatic ).

n celule, apolipoproteinele sunt desfcute naminoacizi, iar esterii de colesterol n

colesterol liber.

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HDL-COLESTEROL

Hepatic, intestinal se sintetizeaz HDL.

HDL preia colesterolul n exces de la celule.

HDL poate fi metabolizat de ficat, apolipoproteineletransformndu-se n aminoacizi iar esterii decolesterol n colesterol liber.

Colesterolul liber - depozitat la nivel hepatic subform de esteri de

colesterol

- sinteza acizilor biliari,

- eliminat direct n bil

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Fiziologia lipoproteinelor plasmatice

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Apo

Nastere B48 CII CIII E B100 AI AII

CHILOMICRONI intestin + + + + +

VLDL ficat + + + +IDL ficat + +LDL ficat +

HDLficat

+ + + + +

TRASPORT

ANTEROGRAD

ApoB

TRASPORT RETROGRADApoA

Structura principalelor lipoproteine

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Apo-proteineClasa majora

deApo-proteine

Funcia

Apo A A I

A II

Trasportul retrograd alcolesterolului (LCAT)

Apo B B 48

B 100

Legarea de LDL-R i clearence-uldin circulaie

Apo C C IIC III

Activarea LPL

Apo E Legarea de Remnant Receptorhepatic i clearence-ul resturilor

de chilomicroni i LDL

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Clasificarea FredricksonTip Lipoproteina

crescut

Lipidul crescut Defectul

Ia Chilomicroni Trigliceride LpL

Ib Chilomicroni Trigliceride Apo CII

IIa LDL Colesterol LDL-RIIb LDL i VLDL Colesterol LDL-R i Apo B-100

III -VLDL Colesterol itrigliceride

Apo E

IV VLDL Colesterol itrigliceride

VLDL supraproduciesau subutilizere

V VLDL i

chilomicroni

Colesterol i

trigliceride

Deficien LpL sau HL

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Indicatii de recoltare Antecedente heredo-colaterale de boala coronarian

prematur :

- tatl sau alt membru de sex masculin rud grad 1 cu IMA saumoarte subit sub vrsta de 55 ani

- mama sau alt membru de sex feminin rud grad 1 cu IMA saumoarte subit sub vrsta de 65 ani.

Triada lipidic :Trigliceride crescuteLDL crescutHDL sczut.

Ali factori :Diabet zaharat

Obezitate central (ATP III 102/90; IDF 94 / 80)Vrsta naintat

Hipertensiune arterial

Fumat

Cresterea PAI-1, CRP

Hiperhomocisteinemie

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Condiii de recoltare

Lipoproteine:

Explorarea de realizez dupa repausalimentar de 12 - 14 ore.

Cu 24-48 de ore nainte de dozare esteinterzis consumul de alcool.

Apolipoproteine:

este util pentru aprecierea riscului deateroscleroz.

Dozarea se face dup repaus alimentar de 12-14 ore.

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Fraciuni lipidice plasmatice

determinate uzual n clinic

Colesterol total

LDL-Colesterol

HDL-Colesterol

Trigliceride

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Valori normaleNormal

(mg/dl)

Risc la

limit(mg/dl)

Risc nalt de afectare

Cardiovascular(mg/dl)

Colesterol

total< 200 200 - 239 > 240

LDL colesterol < 130 130 - 159 > 160

HDL

colesterol

> 45 35 - 45 < 35, la barbati

< 45, la femei.Trigliceride < 150 150 - 200 > 200

AACE Guideline Medical Guidelines for Clinical Practice for the Diagnosis and

treatment of Dyslipidemiaand Prevention of Atherogenesis - Amended Version - 2002

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Valori normale

Normal Normalinalt /aproapenormal

Risc lalimit

Risc inalt Riscfoarteinalt

Colesteroltotal < 200 200 - 239 > 240

LDLcolesterol

< 100 100 129 130 159 160 189 190

HDL

colesterol

40 - 60 < 40

Trigliceride 500

Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation,

and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) -NIH Publication No. 01-3670 May

2001.

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Cauze de dislipidemie

Genetice

Dobandite (Secundare altor afeciuni)

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Cauze genetice de dislipidemie

HDL VLDL LDL TG Defect genetic

Hipercolesterolemiafamilial

++ N LDL-R

Deficit de ApoB ++ N anomalii ApoB

Familial mixt 1/3 1/3 exces ApoB1/3

Hipercolesterolemiapoligenic

+ poligenic

Hipertrigliceridemiafamilial

+ 200-1000

scade activitatea LpL

Hipertrigliceridemiasever

++ >1000 LpL

Hipoalfalipoproteinemia familiala

< 30 B

< 35 F

scade Apo AI

Dis-

betalipoproteinemia

+ + + anomalii ApoE

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Cauze de dislipidemie

Genetice

Dobandite (Secundare altor

afeciuni)

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Colesterolul total i LDL crescute :

hipotiroidism(scade numr receptori LDL, scade

colesterol hepatic, se stimuleaz HMG-coAreductaza).

afeciuni biliare obstructive

afeciunihepatice cronice scade catabolismulLDL colesterol.

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Trigliceride i VLDL crescute (1):

sindrom nefrotic ( proteinurie, scade presiuneacoloid-osmotica ceea ce stimuleaz sintezele

proteice hepatice, inclusiv de apoproteine i

lipopproteine) Diabet zaharat (deficit de insulin deficit de

lipoproteinlipaz, lipoliza accentuat,

hipertrigliceridemie, supraproducie de VLDL).

Obezitate (aport caloric crescut, insulinorezistenperiferic)

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Trigliceride i VLDL crescute (2)

Consum excesiv dealcool(inhib beta-oxidareaacizilor grai, exces de trigliceride intracelular, deci

supraproducie de VLDL).

Hipotiroidism(scade activitatea lipoproteinlipazei)

Sarcin