General PathologyBasic Principles of Cellular and Organ Pathology

SteatosisMitochondrial , Lysosomal,

and

Peroxisomal

Disorders.

Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague

Jaroslava Dušková

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Mitochondria

Peroxisomes–5

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Steatosis. Mitochondrial and Peroxisomal

Disorders - table of contents

Steatosis

– Pathogenesis of cell injury

– morphology

– complications

– differential diagnosis

– organelles involved in lipid metabolismGER + GA

mitochondria (& mitochondriopaties)

lysosomes (acquired and inborn diseases)

– lipids in signaling

– Pathology of peroxisomes (& a case report)

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Pathogenesis of Cell Injury and Cell

Death

ATP depletion

Oxygen and oxygen-derived free

radicals

Intracellular calcium and loss of

calcium steady state

Defects in membrane permeability

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Pathogenesis of Cell Injury & Cell Death

ATP depletion

decrease/loss of mitochondrial ATP

synthesis

cell swelling, lipogenesis & active

cell transport

loss of integrity of plasma membrane

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clinic reversible ireversible

Huether SE, Mc Cance KL: Understanding Pathophysiology

Huether S., Mc Cance K.L. eds.:

Understanding Pathophysiology. 3rd ed., Mosby, 2004, 1235 pages, p.70

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Steatosis (Fatty Change)Definition:

acquired metabolic disorder

with intracellular accumulation

of lipid droplets

(x lipomatosis, adipositas - increase of fatty

tissue amount)

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IM

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Heart Muscle

Tigering Toxic

degenerationFat infiltration

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Adipositas cordis. Atrophia lipomatosa myocardii

ventriculi dx. cordis.

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Steatosis myocardii(tigering, thrush breast heart)

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HS

Steatosis myocardii(tigering, thrush breast heart)

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Steatosis - morphologyMacroscopy:yellowish - orange color of organs

(+ carotenoids - lipochrom)

Microscopy:microvacuolar cytoplasm - foamy

cellmacrovacuolar – unilocular

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Steatosis - techniquesFixation

Freezing - cryostat sections

Watery fixatives – 10% formalin

Staining

Aniline dyes – Sudan Red, Sudan Black, Oil Red

Luxol blue – phospholipids- myelin sheets

Polarization – lung surfactant in premature lungs

Fluorochrome lipid staining with benzpyrene – lung surfactant in premature lungs

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Cirrhosis hepatis ethylica

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Cirrhosis hepatis ethylica

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Hepar moschatum – nutmeg liver

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Steatosis hepatis

LIVER - major organ of fat

metabolism

abnormal accumulations

of TRIGLYCERIDES within

parenchymal cells

Causes:

obesity

alcohol abuse

protein malnutrition

diabetes mellitus, toxins

drugs

anoxia

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Cholesterol Transport

BioFiles, 2007,2,7,p.13

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LDL

Chylomicron

LDL receptor

Lipids in food emulgation (bile salts)

digestion (pancreatic lipase)

micelles

Enterocytes

chylomicrons synthesis

release to lymphatic vessels

to blood and tissues

Tissues

Fatty acids for β-oxidation (lipoprotein lipases)

Cholesterol in the Body dietary – chylomicrons

endogenous (liver – AcetylCoA)

75% - bile acids

skin – kalcitriol

adrenals and gonads - steroid hormones

LDL – cholesterol to the tissues

HDL - produced as a protein rich particle in

the liver and intestine; can transport CH from

the tissues to the liver – scavenger function

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Atherosclerosis initialis aortae

Sudan Red

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Atherosclerosis – foam cells

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Atherosclerosis a. coronariae grave stenosans

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Lipids accumulation in cells

(sometimes causing cellular injury)

normal cellular constituent accumulating

in excess

abnormal substance, usually a product

of abnormal metabolism

pigment

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Processes Resulting in Abnormal

Intracellular Accumulations

Abnormal metabolism of a normal

endogenous substance (e. g. fatty liver)

Lack of an enzyme necessary for the

metabolism of a normal or abnormal

endogenous substance (e. g. lysosomal

storage disease)

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hyperplasia

gl. suprarenalium 25g

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Hypolipoidosis

gl. suprarenalium

( acute stress)

new storage

of lipids

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B5253/05Adenoma gl. suprarenalis

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Myelolipoma

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Kidney – clear cell ca

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Clear Intracellular Vacuoles

& adjunct techniques

accumulations of water neg.

lipides SUDAN, OIL RED

polysaccharides PAS, A-PASJaroslava Duško

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Organelles Involved

in Lipid Metabolism

Granular Endoplasmic

Reticulum GER + Golgi app.

mitochondria

lysosomes

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ERG

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GER - lipoprotein synthesis

enterocytes Apo B48

monoacylglycerols (fatty acids)

triacylglycerols - chylomicrons

hepatocytes Apo B100

Very Low Density Lipoproteins

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Cholesterol Transport

BioFiles, 2007,2,7,p.13

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GER - lipoprotein synthesis

DISORDERS

hepatocytes

lack of Apo B100 synthesis -

toxins

toxic steatosis

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NL

L

SG

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M

LERG

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Mitochondria - beta oxidation

fatty acids - carnitinacyltranpherase 1

+ coenzyme A -

carnitinacyltranspherase 2

beta oxidationJarosla

va Dušková

Mitochondria - beta oxidation

DISORDERS

fatty acids - carnitinacyltranpherase 1

+ coenzyme A - transport malfunction

carnitinacyltranpherase 2

beta oxidation defect - hypoxia, anoxia

hypoxic steatosis

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Mitochondria - semiautonomous

organelles (circular mtDNA, division)

isolated

network

spiral chain

Outer membrane

Inner membrane

Cristae

Matrix

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Mitochondria - semiautonomous

organelles (circular mtDNA, division)

Function

beta oxidation,

Krebs cycle,

OXFOS

protein sorting

& synthesis

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Mitochondria - life cycle

division

majority of

proteins coded in

the nucleus

degradation in

the

autophagosomes

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Protein

Sorting

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Mitochondria - genetics

circular mtDNA

haploid (maternal origin)

2-20 mtDNA molecules in one

mitochondrion

100 -10 000 mtDNA molecules in one

cell

variable amplification

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Mitochondria vs. Nucleusgenetics

circular mtDNA

haploid (maternal

origin)

2-20 mtDNA

molecules in one

mitochondrion

100 -10 000 mtDNA

molecules in one cell

asynchrone replication

linear - chromosomes

diploid 23 pairs

(maternal+paternal)

46 macromolecules per

one nucleus

46 macromolecules per

one cell

synchronized replication

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Mitochondria vs. Nucleusgenetics

homoplasmia

heteroplasmia

polyplasmia

only some copies

normal + mutated

mtDNA

threshold effect

homozygotic

heterozygotic

– carriersJaroslava Duško

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Mitochondria - pathology

acquired

– mitochondriosis

– oncocytic change

inborn

– enzymopathies

Prof. H. Hamperl

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Mitochondria - pathology

inborn - enzymopathiesSynthesis defects (partly nucleus coded):

urea and porphyrine

transport proteins

Krebs cycle enzymes succinate deh.

OXFOS nucleus & mitoch. coded

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Mitochondrial diseases

Progressive external ophthalmoplegias

Mitochondrial encephalomyopathies

Undefined mitochondrial

encephalomyopathies

Mitochondrial myopathies

childhood onset, ophtalmoplegia, weekness….

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Myopathia - ragged red fibres

young age: ophtalmoplegia, weakness, cardiomyopathia

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Somatic mtDNA mutations reported in many types of cancer cells….

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HIF1α destabilization is independent of ROS overproduction.

Porcelli A M et al. Hum. Mol. Genet. 2010;19:1019-1032

Cells bearing mutated mitochondria may gain advantage in a low oxygen/nutrients environment

since they may be more prone to switch their metabolism towards a glycolytic one (d), driving the

shift of the mtDNA mutation towards homoplasmy ….

Oncocytic

tumours

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Oncocytes

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Nephrosis vasoparalytica

- steatosis

Lipoproteinuria

β - oxidation

disorders

KIDNEY -

ischemia

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lysosome

Lysosomes - lipid hydrolysis

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Lysosomes - lipid hydrolysis

enzymes - lipase, phospholipase,

sphingomyelinase etc….

membrane diffusion, reutilisation

storage TAG, ChE

transport from the cell - HDL, apo E

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Lysosomes - lipid hydrolysis

DISORDERS

acquired - intensive endocytosis of lipids

- histiocytes – foam cells

hereditary - lipidoses , lipid storage dis.Jarosla

va Dušková

Cystis dermoidalis inflammata

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Granuloma lipophagicum

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Cholesterolosis mucosae vesicae felleae

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Storage DiseasesDef.:

inborn errors of metabolism (mostly

single gene abnormality) leading to an enzyme defect with subsequent accumulation of the substrate (& lack of the product) in tissues or organs „thesaurismoses“

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Lipidosis (thesaurismosis,

lipid storage disease)

Definition:inborn metabolic disorder

with intracellular accumulation of lipid droplets

(lysosomal enzymopathies)

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Lipidoses - classification

E- defect

Material stored

Location - neuronal, visceral, neurovisceral

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Lipidoses – diagnosis & therapy

E- defect / decreased activity tests

Mutation analysis

Multidisciplinary approach

Substitution of recombinant E

Reduction of stored materiál intake

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Lipid Storage Diseases -1.

Disease E- def Accum.

Lipid

Tissues

Involved

Tay-Sachs

AR

Hexos

aminidase A

GM2

ganglioside

Brain, retinaBlindness, mental

retardation

Gaucher

ARDiff. clin. types

-

Glucosidase

Gluco

cerebrosid

Liver, spleen,

bone marrow,

brain *

Niemann-

Pick AR

Sphingo

myelinase

Sphingo

myelin

Brain, liver

spleen

* substituted E does not cross the BB-barrier

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m. Gaucher (liver)

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Lipid Storage Diseases – 2.

Disease E- def Accum.

Lipid

Tissues

Involved

Metachro

matic AR

Leuco

dystrophy

Arylsulfat

ase A

Sulfatid Brain, kidney,

liver, peripheral

nerves

Fabry´s angiokeratoma

corporis

diffusum GR

-galactosid

ase

Ceramid

trihexosid

Skin, kidney,

myocardiumMultiorgan failure

Krabbe´s globoid AR

leukodystrophy

Galactosyl

ceramidase

Galactol

cerebroside

Brain

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Extracellular Steatosis

blood: hyperlipidemias

– increased size of lipoprotein particles (rel.

decrease of the apoprotein component)

– increased number of lipoprotein particles

removed after oxidation via „scavenger receptors“ –

resulting e.g. into aggravated & accelerated

atherosclerosis, pancreatic necrosis

– arcus senilis myringis, arcus senilis corneae

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Hyperlipidemia

- symptom of many different diseases

Primary – monogenic or polygenic

hyperlipidemias

Secondary – due to other diseases –

e.g. DM, nephrotic syndrome

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Primary Hypercholesterolemia

- mutation of LDL rec. gene

accelerated atherosclerosis

heterozygots – middle age atherosclerosis

complications

homozygots – childhood & adolescence

atherosclerosis complications

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Arcus senilis corneae

Xantelasma

Xanthoma

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Granuloma cholesterolophagicum

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Lipids in Cell Signaling - 1

Many of the lipids involved as second messengers in cell signaling pathways arise from the arachidonic acid (AA) pathway.

AA is an unsaturated fatty acid

a normal constituent of membrane phospholipids

released from the phospholipids by the actions of phospholipase A2 (PLA2).

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Lipids in Cell Signaling - 2

Prostaglandins (PG) are generated by the cyclooxygenase (COX).

Constriction or dilation in vascular smooth muscle cells

Aggregation or disaggregation of platelets

Sensitize spinal neurons to pain

Decrease intraocular pressure

Regulate inflammatory mediation

Regulate calcium movement

Control hormone regulation

Control cell growth

Short half-life. Therefore, they exert only a paracrine(locally active) or autocrine (acting on the same cell from which it is synthesized) function

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Lipids in Cell Signaling - 3

Leukotrienes (LT) and lipoxins (LP), are

derived directly from AA without the mediation

of a cyclic endoperoxide.

LT induce inflammation by their chemotactic

and degranulating actions on

polymorphonuclear leucocytes (PML)

the amino acid containing LTs induce

vasoconstriction and bronchoconstriction and

are involved in asthma and anaphylaxis.

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Pneumonia

lobarishepatisatio flava

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Peroxisomes - microbodiesup to 2 microns – catalase

(in kidney and liver up to 10 times larger)

Function

Degradation: substrate oxidation (etanol)

Anabolism: synthesis of prostaglandins,

cholesterol, billiary acids,

plasmalogens, gluconeogenesis,

transamination

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Peroxisomes

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Peroxisomes - microbodiesDISORDERS

Lack of:Degradation: substrate oxidation

e.g. etanol...

Anabolism: synthesis of

prostaglandins , cholesterol,

billiary acids, gluconeogenesis,

transamination...

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Case report

Zellweger cerebrohepatorenal syndrome

(ZWS)

Def.:

inborn metabolic defect(s)

of several proteins involved in the

assembly of peroxisomes

(5 ZWS variants described sofar)

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Case report

Zellweger cerebrohepatorenal syndrome

(ZWS)

Clinic:

onset at birth – severe hypotonia &

dysmorphia- high forehead, epicanthic folds,

abnormal ears, micrognathia, arched palate

epilepsy, failure to thrive, psychomotor retardation,

pigmentary retinopathy, abnormal liver function

death at about 5 months of age

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Case report

Zellweger cerebrohepatorenal syndrome

(ZWS)

Boy, born from 1st pregnancy in 40th week

2750g/51cm

mother 30yrs, father 31yrs, healthy, non-related

AFP (alpha-feto-protein) positive, after correction of

gestational and USG age of pregnancy negative,

amniocenthesis not performed

born asphyctic, dysmorphia, hypotonia,

hyporeflexia, hypomotility, Apgar 1-5-5

Apgar Score:

• heart rate

• respiration

• muscle tone

• reflex

irritability

• color

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Case report Zellweger cerebrohepatorenal

syndrome

(ZWS)

Genetic investigation

insertion T, position c.2097-2098insT in gene PEX1 in

homozygot status (exon 13, preliminary termination codon

creation), PEX1=peroxin 1, RNDr. Petrovič,PhD, Bratislava

peroxisomal biogenesis disorder (complete lack of

peroxisomes in all cells - Zellweger syndrom.

autosomal recessive heredity - risk 25% for each pregnancy

of healthy parents – carriers

genetic consultation and prenatal diagnostics

recommended

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Case report

Zellweger cerebrohepatorenal syndrome

(ZWS)

Course

hypotonia, no development – neonate level

frequent asphyxia episodes, no succion reflex,

nasogastral canulation for nutrition

hepatopathy

died at 8th months - bronchopneumonia

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Pachygyria

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frontal lobes-neuronal dystopia in white matter

ZWS

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dystopia of

Purkyne cells

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nucleus olivarius widening of the dorsal zone

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I. Defectus metabolicus hereditarius - Syndroma Zellwegeri: Atrophia

cerebri periventricularis. Pachygyria. Dystopia neuronalis cerebri, medullae

oblongatae et cerebelli. Cirrhosis micronodularis hepatis (322,9g).

Hypotonia. Hypotrophia (4001g pro norma minima 7000g). Cystes

subcapsulares renum dispersae.

Defectus septi secundi.

II. Bronchopneumonia catarrhalis purulenta iterata peracta therapia

antibitioticis curata. Tracheitis catarrhalis purulenta acuta.

Bronchopneumonia catarrhalis purulenta acuta focale abscedens loborum

omnium pulmonum, praecipue loborum inferiorum. Insufficientia

cardiorespiratoria terminalis.

III. Bronchopneumonia.

IV. Fetus maturus, generis masculini, ponderis 2750g, longitudinis 51cm.

Graviditas I., hebd. XL. Partus maturus spontaneus positione occipitali.

Asphyxia postnatalis peracta oxygenotherapia curata.

Diagnosis clinico-pathologica

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