Bilirubin and Jaundice - · PDF fileBilirubin and Jaundice ... Jaundice Defect in Conjugation...

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Transcript of Bilirubin and Jaundice - · PDF fileBilirubin and Jaundice ... Jaundice Defect in Conjugation...

  • 1

    Bilirubin and Jaundice

    Pathways of Bilirubin Synthesis and Catabolism

    Porphogens

    Fe

    Heme

    Globin

    Hgb

    +

    +

    Urobilinogen StercobilinFecalPigments

    UrineUrobilinogen

    Heme PrecursorsMyoglobinNon-Hgb HemeProteins

    ShuntPathwayFree Bilirubin Albumin Complex

    ConjugatedBilirubin

    Hgb

    Biliverdin

    Bilirubin

    Fe

    Globin

    RBCsBone

    MarrowReticuloendothelial

    System (RES)

    2mg

    70mg

    68mg

  • 2

    Labeling of RBC hemoglobin and fecal stercobilin

    0.3

    0.2

    0.1

    0.1

    0.08

    0.06

    0.04

    0.02

    20 40 60 80 100 120 140 160 180

    A:

    Ato

    m %

    exc

    ess

    15N

    of

    ster

    cob

    ilin

    B:

    Ato

    m %

    exc

    ess

    15N

    of

    hae

    min

    B

    A

    Times ( days)

    Labeling of red cell hemoglobin and fecal stercobilinin a normal human given 15N orally

    X

    X X

    X X X

    XX

    X

    X X

    X

    X

    X

    X

    Sources of bilirubin production in the rat

    Early Bilirubin15%

    0-3 Days

    Late Bilirubin65%

    40-80 Days

    Non-HemoglobinSources (liver)

    Red CellSenescence

    IncreasedErythropoiesis

    Sources of bilirubin production in the rat, as adduced from studies of thelabeling of plasma bilirubin in Gunn rats and bile bilirubin in normal rats.

  • 3

    NN

    N NFe

    COO COO

    C

    NN

    N N

    OOC COO

    OH HO

    H H

    H

    NN

    NH N

    OOC COO

    OH HO

    H

    NADPH NADP

    O2NADPHNADP

    Fe (II)O2 CO

    Biliverdin

    reductase

    NADPHNADP

    Hemin +

    heme-oxygenase complex

    hydroxyheme-oxygenase complex

    biliverdin

    bilirubin

    NN

    N NFe

    COO COO

    OH

  • 4

    OATP MDR2

    (ligandin)

    A.

    B.

  • 5

    N NH

    NNHFe

    Me

    CH

    CHCH2

    Me

    CH2 CH2 CO2H

    MeMe

    H2C CH2 CH2 CO2H

    A B

    CD

    NH

    NH

    NH

    CH CH2CH

    NH

    O

    MeCH2MeCHMe Me CH

    O

    CH2C

    CH2CH2C

    CH2

    OO O OO O

    OH

    OHHO

    COOH COOH

    OHHO

    HOCH2

    NH

    NH

    NH

    CH CH2CH

    NH

    O

    MeCH2MeMe Me CH

    OA B C D

    CHCH2 CH2

    CO2H

    CH2CH2CO2H

    CH2

    A B

    C

    D

    BILIRUBIN - IX DIGLUCURONIDE

    BILIRUBIN IX (convoluted structure)

    BILIRUBIN IX (planar structure)

    A.

    B.

    C.

    CO (excreted via lungs)

    Fe (reutilized)

    HN

    HN

    NH

    NH

    C OO

    C

    C

    OO

    OO

    H

    H

    HN

    HN

    NH

    NH

    C OO

    C

    C

    OO

    OO

    H

    GA

    HN

    HN

    NH

    NH

    C OO

    C

    C

    OO

    O

    GA

    OGAConjugation prevents

    internal H-bonding by the-COOH groups of Bilirubin

    BILIRUBINS:

    UNCONJUGATED (UCB)

    MONO-GLUCURONIDE

    (BMG)

    DIGLUCURONIDE(BDG)

    2

    1

    BILIRUBIN CONJUGATION IN MICROSOMESINVOLVES TWO STEPS, MEDIATED BY

    ONE BILIRUBIN-UDPGA TRANSFERASE

    UDPGA

    UDP

    UDPGA

    UDP

    UDPGATRANSFERASE

  • 6

    OATP MDR2

    (=cMOAT)

    UROBILINOGENS ARE FORMED BY DECONJUGATION AND REDUCTION OF BILIRUBINS BY INTESTINAL BACTERIA

    CONJUGATED BILIRUBIN

    UNCONJUGATEDBILIRUBIN

    Deconju-gation

    A UROBILINOGEN

    Reduction

    NHN H

    HN HN

    COOGA COOGA

    M

    MV

    M VO O

    M

    NHN H

    HN HN

    COOH COOH

    M

    MV

    M VO O

    M

    NHN H

    HN HN

    H2C CH2

    COOH COOH

    M

    ME

    M EO O

    M

    H H

    2 GA + 8HM = MethylE = EthylV = Vinyl

  • 7

    Slow

    Fast

    FRACTIONAL DIAZO REACTION OF PLASMA

    R R

    Directreaction

    Indirectreaction

    CONJUGATEDBILIRUBIN

    UNCONJUGATEDBILIRUBIN

    N+

    N

    SO3H

    +

    N+

    N

    SO3H

    +

    DIA

    ZO

    RE

    AG

    EN

    T

  • 8

    R R

    CONJUGATEDBILIRUBIN

    UNCONJUGATEDBILIRUBIN

    N+

    N

    SO3H

    + + ACCELERATOR(ALCOHOL, CAFFEINE)

    TOTAL DIRECT INDIRECT=

    TOTAL DIAZO REACTION OF PLASMA

    Bilirubinuria in Jaundice

    UNCONJUGATED PLASMA BILIRUBIN (B) CONJUGATED

    NO BILIRUBIN BILIRUBIN ++

    URINE

    PLASMA

    (A=ALBUMIN)

  • 9

  • 10

    Phototherapy for neonatal jaundice

    Treatment for Neonatal JaundicePrevention of kernicterus

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    NH

    NH

    NH

    CH CH2CH

    NH

    O

    MeCH2MeMe Me CH

    OA B C D

    CHCH2 CH2

    COOH

    CH2CH2COOH

    CH2

    NH

    NH

    NH

    CH CH2CH

    NH

    O

    CH2MeMe Me CH

    O

    CH2COOH

    CH2CH2CH2COOH

    Me CHCH2

    Structure of the and isomers of bilirubin IX. In the IX isomer (and in the and isomers, not shown) the propionic acid groups are moved to positions other than those indicated on the central pyrrole rings B and C of bilirubin IX.

    Bilirubin IX

    Bilirubin IX

    2.5

    2.0

    1.5

    1.0

    0.5

    16

    12

    8

    4

    0 8 16 24 0 2 4 6 8 10

    LiverCo-PPLiverSn-PP

    Hem

    e O

    xyge

    nase

    (nm

    ol b

    ilirub

    in/m

    g ph

    Effect of Sn-protoporphyrin (Sn-PP) and CO-protoporphyrin (Co-PP) when administeredonce at a dose of 50 mol/kg body wt on hepatic heme oxygenase activity in the rat.

    Time(hours) (days)

  • 12

    18

    16

    14

    10

    -4 0 2 4 0 1 2 3 4 5 6 7

    12

    2.5

    5.0

    7.5

    10.0

    Effect of Sn-protoporphyrin (Sn-PP) (100 mol/kg body wt) administeredat 4d before and on the day of surgery on hyperbilirubinemia in the

    bile-duct-ligated rat. Effect of Sn-PP (2 x 0.25 mol/kg body wt) on the levels of serum bilirubin in a patient with primary biliary cirrhosis (PBC).

    Time (days)

    Bile-DuctLigation

    RAT PBC(50 )

    Sn-PP

    Pla

    sma

    Bilir

    ubin

    mg/

    dl Control

    Sn-PP

    UGT1 gene

    1J 1I 1H 1G 1F 1E 1D 1C 1B 1A 2 3 4 5

    5 3

    mRNA B-UGT1

    Phenol

    UGTs

    NH2 COOH

    enzymesubstrate binding site UDPGA

    binding sitemembranespanningregion

    285 amino acids 246 amino acids

  • 13

    UDPGT promoter A(TA)6TAA

    UDPGT nullMutation

    Bolivian Squirrel MonkeyGunn ratAnimal Model

    BenignKernicterusPrognosis

    2-7% of populationRarePrevalence

    Increased proportion of monoglucuronide

    Small amounts of unconjugatedbilirubin

    Pigments in bile

    ReductionNo effectEffect of Phenobarbital on plasma bilirubin

    30-50% of normalUndetectableHepatic bilirubin-UDPGT activity

    Usually normal; elevated in a minority of cases

    NormalPlasma BSP retention at 45 min

    50-85 M (fluctuates)340-860 MPlasma bilirubin

    Gilbert SyndromeCrigler-Najjar Type ICharacteristics

    Unconjugated Hyperbilirubinemia

    MRP2Mutation

    BenignBenignPrognosis

    RareUncommon (1:1300 in Persian Jews)Prevalence

    Autosomal recessiveAutosomal recessiveMode of inheritance

    Elevated total; elevated proportion of coproporphyrin I but 80% as coproporphyrin IUrinary coproporphyrin

    Elevated; no secondary rise at 90 min

    Normal or elevated; secondary rise at 90 min45-min plasma BSP retention

    Normal except for bilirubinNormal except for bilirubinRoutine liver function tests

    Elevated, usually between 2 and 5 mg%, occasionally as high as 20 mg%; predominantly direct-reacting

    Elevated, usually between 2 and 5 mg%, occasionally as high as 20 mg%; predominantly direct-reacting

    Serum bilirubin

    NormalDark pigment; predominantly in centrilobular areas; otherwise normal

    Histology of liver

    NormalGrossly blackAppearance of liver

    Rotor SyndromeDubin-Johnson SyndromeCharacteristic

    Chronic conjugated hyperbilirubinemias

  • 14

    Hemolysis Hepatocellular

    Conjugated bilirubin

    Jaundice

    Defect in Conjugation

    Unconjugated bilirubin

    Intrahepatic Extrahepatic

    Cholestatic

  • 15

    Hemolysis Hepatocellular

    Conjugated bilirubin

    Jaundice

    Defect in Conjugation

    Unconjugated bilirubin

    Intrahepatic Extrahepatic

    Cholestatic

  • 16

    Liver Function Tests

    Bilirubin PT (Prothrombin time) Glucose Cholesterol ALT (alanine aminotransferase) AST (aspartate aminotransferase) Alkaline phosphatase GGT (-glutamyltranspeptidase)

    Imaging

    Ultrasound CT scan Liver-spleen scan Radionuclide biliary scan ERCP (endoscopic retrograde

    cholangiopancreatography) Transhepatic cholangiography

  • 17

    Hemolysis Hepatocellular

    Conjugated bilirubin

    Jaundice

    Defect in Conjugation

    Unconjugated bilirubin

    Intrahepatic Extrahepatic

    Cholestatic

    BR

    Nl BD Dilated BD

    AP ALT

  • 18

    Bilirubin Metabolism

    BloodConjugated & Conjugated

    Urine UrobilinogenStool Stercobilin

    NH

    NH

    NH

    CH CH2CH

    NH

    O

    MeCH2MeMe Me CH

    OA B C D

    CHCH2 CH2

    COOH

    CH2CH2COOH

    CH2N

    N N

    N

    Fe

    MV

    V

    M

    CH2

    CH2

    COOH

    M

    M

    CH2

    CH2

    COOH

    plus 3 O minus Fe

    minus CO

    A

    B

    D

    C

    Ferroprotoporphyrin IX(Protoheme)

    Bilirubin IX

    Conversion of protoheme (ferroprotoporphyrin IX) to bilirubin IX