Biochemistry Diagnosis of Liver and Gallbladder

Anatomic and Physiology Anatomic structure characteristichepatic portal vein) Approximately 75% of the blood supply comes from the portal veinDrains the GI tract and is rich in nutrients(hepatic artery) Remainder of blood supply enters by hepatic artery Rich in oxygendouble blood supply

(hepatic vein) (systemic circulation) -(kidney)- uria (biliary tract ) (intestinal tract)-(faeces)

Cell surface have a lot of microvilli() (sinusoid)Cell membrane have relatively high permeability Abundance mitochondria in cell Cell have abundance rough surfaced endoplasmic reticulumsmooth surfaced endoplasmic reticulum and Golgi complex Cell have abundance enzyme (morphological structure) (chemical composition)

Metabolism Carbohydrate, Fat & ProteinLiver Functions:Secretory bile-Bile acids, salts & pigmentsExcretory BilirubinSynthesis Albumin, coagulation factorsStorage Vitamins, carbohydrates etc.Detoxification toxins, ammonia, etc.

Metabolic change of hepatocellular injury () (Dysfunction of substance metabolism)

1 (Glucose metabolism) Important role in metabolism of glucose and regulation of blood glucose

Converts glucose to glycogen (storage)

Breaks down glycogen into glucose (energy)

glucose is synthesized through gluconeogenesis (amino acids or lactate)

Fasting-plasma glucose(FPG) decreased glycogenesis disorder glycogen storage decreasedPostchallenge plasma glucose(PPG) increased (disease of the liver)

(serious disease of the liver)(aerobic oxidation)(tricarboxylic acid cycle)(pyruvic acid ) (disease of the liver)(phosphopentose pathway) (glycolytic pathway) OGTT

Synthesizes all plasma proteins except gamma globulinAlbumin (osmotic pressure)Alpha and beta globulinsBlood clotting factorsSpecific transport proteinsProthrombin: liver needs vitamin K2 (Protein metabolism)

Ammonia (potential toxin) is byproduct of gluconeogenesis(Liver converts ammonia into ureaAlso removes ammonia produced by intestinal bacteria from portal bloodUrea is excreted in urineAmmonia Conversion

(albumin)(globulin) (A/G) 1 (chronic hepatic parenchymatous injure) 1.(synthesis protein)coagulation factor (coagulation disorder)plasma protein albumin (hypoalbuminemia)

(transamination) (deamination) (decarboxylase) / (Branched-chain amino acid/Aromatic amino acid)BCAA/AAA)(transaminase) ALTBranched-chainExtrahepatic metabolism (LeuIleValAromatic Liver metabolism TrpTyrPhe /=3-3.5/12.(amino acid metabolism)

.(ammonia) (urea) blood ammonia () BCAA/AAA(/)aminehepatic encephalopathy(HE)

Fatty acids broken down into ketonesProvide source of energy for muscles and other tissues.Occurs when glucose is limited as in starvation or uncontrolled diabetesFatty acids also used for synthesis of cholesterol, lipoproteins and other complex lipids(Lipid metabolism)

.(digest and absorb) : (cholesterol) (bile acid) Steatorrhea. (synthesize and transport )Synthesize TGChE/ChPLLCAT acetone body() TransportVLDLHDL

(decompose)TGFAfat oxygenolysis decreaseExcess fat accumulate in hepatic cells fatty liver (5%)

(Dysfunction of coagulation and fibrinolysis) (Dysfunction of immunity)

(vitamin metabolism) 1(absorption bile acid-fat-soluble vitamin2transform synthesize coenzyme Provitamin A vitamine A vitamin D3 25-OH-D3

inactivation of hormone

steroid hormone Protein hormoneCatecholamine hormone

(skin spider) (liver palms) ( face pigmentation)

Biotransformation biotransformation)

Biotransformation reaction biotransformation) Exogenous non-nutrient(drugToxin Carcinogens)

Endogenous non-nutrient (hormone), NH3,(neurotransmitter), Bilirubin ,(amine)

(Phase I)(oxidation) (reduction)(hydrolysis)( increasing polarity(type)

Oxidation: alcohol, aldehyde, ketone, monoamine, aromatization, molybdenum, flavin Key oxidation enzyme: cytochrome P450

Reduction: azo- and nitro-, carbonyl, disulfide, sulfoxide, quinone, dihydropyrimidine

Hydrolysis: functional group such as carboxylic acid ester, amide, thioester, acid anhydride

(conjugation reactions) CoAGSHLess toxic ,easy for excretion(Phase II)

Feature of biotransformation 1.continuity

2.multiplicity ++

3.detoxifcation/ carcinogen 34-

Drugs or poisoninhibitor or inducer Age, Sex .Race Condition of liver and kidneyphysiological significances.detoxication .the products are less toxic or carcinogen Factors influence (

metadolism of bilirubin and abnormity

bilirubin metabolism formation transportation liver metabolis extrahepatic metabolism excrete

1 heme)bilirubin)

Extravascular Pathway for RBC Destruction(1)heme)

heme oxygenaseFe2+NADPH+H+NADP+biliverdin reductase(2)bilirubin)greenred-orange

4 3 2 1 0

Methine-carbon bond

Hydrophilic groups lipotropyHydrophobicity bilirubin through the cells into the bloodintracelular

2bilirubin in the blood transfer (signification)1in favor of transport 2restrict bilirubin into cell-bilirubin-albumin indirect bilirubin unconjugated bilirubin free bilirubin

3bilirubin in hepatic cells metabolize(uptake)(transform)(excrete) (1)(uptake)-Y-Z

2(transform)(bilirubin)B-UGT direct bilirubin conjugated bilirubin

3(excrete)conjugated bilirubin (Anion carrier)(bile) bile capillary (bile) intestinal tract

4 metabolism of bilirubin in intestine and bilinogen enterohepatic circulation mesobilirubinogenstercobilinogenurobilinogen

mesobilirubinogenstercobilinogenurobilinogen bilinmesobilirubinstercobilinurobilinbrown color of fecesyellow color of urine

(10%-20%)(95%)(concept of bilinogen enterohepatic circulation)In intestine (10% -20%) of bilinogen -intestinal cells could be reabsorbed ,by hepatic portal vein into liver, most of them (95%) and then with the bile into the intestine, form bilinogen circulation

(urine bilirubin)(urobilinogen) (urobilin)concept)

NORMAL BILIRUBIN METABOLISM Uptake of bilirubin by the liver is mediated by a carrier protein (receptor) On the smooth ER, bilirubin is conjugated with glucoronic acid, xylose, or ribose Glucoronic acid is the major conjugate - catalyzed by UDP glucuronyl tranferaseConjugated bilirubin is water soluble and is secreted by the hepatocytes into the biliary canaliculi Converted to stercobilinogen (urobilinogen) (colorless) by bacteria in the gut Oxidized to stercobilin which is colored Excreted in feces Some stercobilin may be re-adsorbed by the gut and re-excreted by either the liver or kidney Uptake of bilirubin by the liver is mediated by a carrier protein (receptor) On the smooth ER, bilirubin is conjugated with glucoronic acid, xylose, or ribose Glucoronic acid is the major conjugate - catalyzed by UDP glucuronyl tranferaseConjugated bilirubin is water soluble and is secreted by the hepatocytes into the biliary canaliculi Converted to stercobilinogen (urobilinogen) (colorless) by bacteria in the gut Oxidized to stercobilin which is colored Excreted in feces Some stercobilin may be re-adsorbed by the gut and re-excreted by either the liver or kidney

(normal serum) (total bilirubin,TB)conjugated bilirubindirect bilirubin,DB TB1.71-17.1 mol/L DB0.51-3.42 mol/Lunconjugated bilirubin indirect bilirubin Disorder of bilirubin metabolism and jaundice

(jaundice)1concept)(latent jaundice) TB17.1 -34.2mol/L (clinical jaundice) TB>34.2mol/LA variety of diseases caused by increased serum total bilirubinBilirubin into tissue cell Yellow discoloration of skin & sclera due to excess serum bilirubin

Jaundice may result from:increased production of bilirubin impaired metabolism of bilirubin reduced bilirubin excretion combination of the above

2(classification)(1) hemolytic jaundice hepatocellular jaundice obstructive jaundice2 (prehepatic jaundice) (hepatic jaundice) (posthepatic jaundice) 3

Over production of Bilirubin (Hemolytic) A variety of causes excessive red blood cell damage generate too much unconjugated bilirubinexcess the combination of ability and excretion of liver cells hemolytic jaundice.

Impaired hepatic function (Hepatitic)Hepatocellular dysfunction in handling bilirubin(uptake,combine,excrete) unconjugated bilirubin or conjugated bilirubin increased

excretion dysfunction the bile reflux ,conjugated bilirubin in the blood increased Obstruction to bile flow (Obstructive)Intrahepatic cholestasisExtrahepatic Obstruction (Surgical Jaundice)

Type of jaundiceBilirubin metabolismPrehepatic (increased plasma unconjugated bilirubin)Degradation of haem from haemoglobin, myoglobin and cytochromes produces bilirubinBilirubin is bound to albumin to make it water soluble and is transported to hepatocytesHepatocellular (increased plasma conjugated and unconjugated bilirubin)Bilirubin is taken up by hepatocytes and conjugated with glucuronic acid to make it water soluble Obstruction (plasma conjugated bilirubin particularly increased)Bilirubin conjugates excreted into biliary tractObstruction to bile outflow may be intrahepatic or extrahepaticIn intestine bilirubin may be deconjugated and metabolised to bilinogens

1mg/dl1mg/dl1mg/dl1mg/dl00.7mg/dl 40280mg/24h

1mg/dl>1mg/dl>1mg/dl00.8mg/dl

1 2

Bile acid metabolism and its abnormity

(composition of bile) Bile from the liver cells to bile acids, inorganic ions such as water and released into the tube formed by bile canaliculi .

bile pigment cholesterolinorganic salt

To promote digestion and absorption of fat To promote the absorption of fat-soluble vitamins Regulation of cholesterol metabolism, The maintenance of cholesterol in the bile of the state of dissolution ,()Functon of bile acid

Reduce oil/water surface tension /Make the hydrophobic lipids in aqueous micro-emulsion into a small micelle:-

(precursor) (cholesterol ) (site) (liver) (type) Metabolism and function of bile acids Biosynthesis of primarybile acidsconcept)Cholesterol in the liver cells generated into bile acids

cholic acid chenodeoxy cholic acidglycocholic acid taurocholic acidglycochenodeoxycholic acidtaurochenodeoxycholic acid

(site):(small intestine) (large intestine) Biosynthesis second bile acid Primary bile acid secretion by the intestinal bacterial role in post-generated productconcept)

Bile acid is a negative feedback regulation Thyroid hormone may promote bile acid synthesis(synthesis process) 7-(Hydroxylase)(regulation)

- Bile acid synthesis by the liver cells, secreted into the bile into the intestine after most of the weight can be absorbed through the portal vein back to the cycle of the liver, liver cells from the intake, and the synthesis of new bile acid secretion with bile into the intestines -- Between the liver and intestine bile acid cycle known as the bile acid enterohepatic circulation.concept). Enterohepatic circulation of bile acid

;/, Limited Bile acids play maximize the role of the emulsion; Bile acid / cholesterol ratio constant, Is not easy to form cholesterol gallstone. Enterohepatic circulation of bile acid(signification)

Clinical biochemistry of hepatocirrhosisconcept)Cirrhosis is a pathological diagnosis.It is characterized by widespread fibrosis with nodular regeneration. Its presence implies previous or continuing hepatic cell damage.

(viral hepatitis) (alcoholic hepatitis) (cholestasis) severe heart failure) (hepatolenticular disease) -- antitrypsin deficiency) Aetiology

1. Cirrhosis of the biochemical mechanismsIHypoxia and inflammatory stimulation, resulting in enhanced synthesis of collagen fibers. I type in the main-and .HBVLack of immune function, liver cells from recurring destruction of HBV, as well as nodular liver cell regeneration, continuous proliferation of fibrous tissue, leading to cirrhosis.

KufferKuffer cells with a variety of cytokines and bio-active substances, such as collagenase, as well as fat-storing cells produce collagen and so on.Many of the genetic factors involved, this has become a liver cell injury in response to the independent pathogenic factors.1. Cirrhosis of the biochemical mechanisms

2. 1. -- TP,ALB,A/G,,2.--- 3. ---ALTASTMAO4. VitK Liver function test

(classification)(Mitochondria) 2(Connective tissue) 2monoamine oxidaseMAOdistribution)

MAOSchiff MAO

- -proline hydroxylase -PH -PH -PH

hyaluronic acid HA,HA

LNLN

procollagen III peptidePIIIP

IVLiver needle biopsy

hepatic encephalopathy Hepatic encephalopathy is a syndrome observed in patients with cirrhosis of the liver. It is characterized by personality changes, intellectual impairment, and a depressed level of consciousness.1concept)

2Clinical presentation

3Etiology - Cirrhosis (all kinds), most of liver cirrhosis, up to see the door - shunt (Natural intrahepatic or shunt surgery) Acute or fulminant hepatic failure : severe hepatitis (viral, toxic, drug-induced) Primary liver cancer, acute fatty liver of pregnancy, severe biliary tract infection A variety of end-stage liver disease

4inducement Upper gastrointestinal bleedinginfectiona large number of potassium diuretic rowput asciteshigh-protein dietconstipationuremiahypnotic sedativesanesthetics surgical

5Ammonia intoxication hypothesis -/ GABA/BZ)

1)pH (Metabolism)(Source)

pH NH3 (NH4+ NH3 NH4+ NH3NH4+ pH pH>6 pH

(2)scavenger pathway of ammonia ATP NH4+

NH3 productionNH3 clearance urea cycle Ammonia intoxication hypothesisUnder normal condition, the production and the clearance of NH3 is in balance

Upper alimentary tract bleedingGastrointestinal dysfunction Renal dysfunctionMuscle contractionPortal-systemic shuntNH3 productionNH3 clearanceCausesSevere hepatic dysfunctiondysfunction of urea cyclesubstrate ATP , enzyme inactivation

Decreasing energy productionChanging neurotransmitters increasing glutamine and GABA decreasing glutamic acid and acetyl cholinea(Disturb membrane function Effect of ammonia on CNS

Severe hepatic dysfunction Urea synthesis hyperammonemiaElevated level of brain ammoniaBrain dysfunctionSummary of ammonia intoxication

2 fasle neurotransmitter hypothesis False neurotransmitter: molecular structure similar to the normal neurotransmitter, but it can not transmit nerve impulses or the role of the weak, resulting in some parts of the nervous system dysfunction occurred, so that the occurrence of abnormal brain inhibitory, resulting in a coma.

(1)

(2) ()

()

()

3Amino acid imbalance theory

(1) BCAA /AAA 3~4/1(2) BCAA /AAA 1/1(3)AAABCAA AAA 5-5-(4)AAABCAA AAABCAA BCAA

5-(5-hydroxytryptamine,5-HT)5-

5 - HT is a central nervous system inhibitory neurotransmitter, norepinephrine is the antagonist. Brain 5 - HT may be caused by increased sleep, so that it may be caused by hepatic coma is an important reason.

4 GABAGABA hypothesisGlutamic acid- -aminobutyric acid GABAdecarboxylase---GABA Activation of GABA receptor --- Opening of Cl- channel --- Membrane hyperpolarization of neuron

5mercaptanmethyl mercaptan dimethylsulphide

1 ------HS-CH3, HS-CH2CH3 /---- -----8

Na+-K+ATP

2 -----

Lab test 1blood ammonia: 2,endotoxin 3(disseminated intravascular coagulation DIC)

Lab tests of liver function

(protein metabolism)(lipid metabolism)(glucose metabolism)Total proteinA/GPre-albuminIgBlood ammoniaAFPCEATChChELecithoid()TGLipoprotein XApoproteinBile acidfasting blood-glucoseOGTTGalactose tolerance tests()Pyruvic acid Lactic Acid

Liver cell permeability

Liver cell necrosis

ALT OCT SDHAST GDH MAOalanine aminotransferaseaspartate aminotransferaseGPTGOTdistribution cytoplasm > mitochondria> colorimetry5-258-28continuous monitoring5-40U/L8-40U/L

3

ALP alkaline phosphataser-GT -glutamyltransfarasedistribution kidneyliverpancreasmetabolismALPsignification()

ALP 20%

4(Liver cancer and hepatic fibrosis)

Liver cancerhepatic fibrosisALP-GT -L-(-L- fucosidaseAFUmonamine oxidase,MAOproline hydroxylase,PH

5 AST/ALT ratio

Liver cell damageALT ASTCholestasis-GTALP5-NThepatic fibrosisMAOPHliver cancer AFPALP-GTAFU

Bile Salts - Intestinal Natural Detergents:Bile acids are produced in the liver and secreted in the intestine via the gall bladder. Bile acids are oxidation products of cholesterol. First the cholesterol is converted to the trihydroxy derivative containing three alcohol groups. The end of the alkane chain at C # 17 is converted into an acid, and finally the amino acid, glycine is bonded through an amide bond. The acid group on the glycine is converted to a salt. The bile salt is called sodiumglycoholate. Another salt can be made with a chemical called taurine.The main function of bile salts is to act as a soap or detergent in the digestive processes. The major action of a bile salt is to emulsify fats and oils into smaller droplets. The various enzymes can then break down the fats and oils.QUES. Explain how bile salts work to emulsify fats. Talk about the polar and non-polar parts of the molecule.