Download 7 autog. pigments

General Pathology
Basic Principles
of Cellular and Organ
Pathology
Autogenous
Pigments
Jaroslava Dušková
Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague
Pigments
Definition:
colored substances
in the organism
or environment
Pigments
Classification:
 endogenous



autogenous
hemoproteins derived
exogenous
Autogenous Pigments
- color
substances formed in the
organism as metabolism products

melanin

ceroid

lipofuscin
Melanin

oculocutaneous
(origin from tyrosine in melanocytes)

neuromelanin - subst. nigra
(origin from dopamin)
Melanin - types

eumelanin – insoluble , brown-black

phaeomelanin – soluble, yellow-red
(high sulphur content)
Melanin - production
Melanocytes
– derived from the neural crest
– present in the basal layer of epidermis,
dermis, hair folicles, mucose membranes,
uveal tract of the eye, meninges, inner ear
– secretory in the contact with the epithelial
cells - cytocrinia
Melanin Functions – 1.

cytoprotective
– light absorption & conversion of the photon
energy into heat
– uvea – absorption of the light
retina
protection of light overexposure
– retina - visual acuity preventing light
reflexion from the fundus
Melanin Functions -2.

Ion exchanging capacity
Melanosomes can also act as detoxyfiing and
excretory components accumulating great number
of drugs and toxic component e.g. heavy metals.
Scavengers of the free radicals.
Rarely cytotoxic – photosensibilisation
Melanin - Features

brown

destained with H2O2

reducing AgNO3
Disorders
of Melanin Pigmentation
Lack
 generalized

local
– total albinism
– vitiligo
– parcial
albinism
– leucoderma
Albinism

autosomal recessive heredity
– tyrosinase deficiency
– tyrosinase positive – melanosomes defect

oculo-cutaneous albinoidism – dominant
inheritance
Disorders
of Melanin Pigmentation
Lack
 generalized

local
– total albinism
– vitiligo
– parcial
albinism
– leucoderma
Vitiligo

familial aggregation

polygenic nature

association with other
autoimmune diseases (DM,
thyroiditis, gastritis)

ab against tyrosinase in the serum

autoreact . T- cellular cytotoxicity
Disorders
of Melanin Pigmentation
Lack
 generalized

local
– total albinism
– vitiligo
– parcial
albinism
– leucoderma
Leucoderma

postinflammatory
circumscribed depigmentation
e.g.
– leucoderma syphyliticum
– leucoderma psoriaticum
Disorders
of Melanin Pigmentation
Increase
 generalized
– Adison
disease

local
– freckles, nevi
– chloasma /melasma
– melanodermia
– melanoma
Metabolic Disorders- Enzyme Defects

substrate accumulation – storage diseases
(lipidoses, glycogenoses, mucopolysaccharidoses)

toxicity of substrate, crystalisation

alternative metabolic way – toxic product -
cystinosis, urates – gout
phenylketouria
Disorders of Phenylalanine
and Tyrosine Metabolism
1. Phenylalanine hydroxylase
PHENYLKETONURIA
2. Homogentisic acid oxydase
ALKAPTONURIA
3. Tyrosinase
ALBINISM
Disorders of Phenylalanine
and Tyrosine Metabolism
Phenylalanine
1
Homogentisic
acid
methyl–
acetoacetic
acid
Norepinephrine
Epinephrine
Tyrosine
3
DOPA
MELANIN
Ceroid

features
–
–
–
–

light brown
PAS +
acidoresistent
Sudan +-
origin
–
–
fagocytosis od lipid substances by
macrophages
oxidation of non–saturated lipid acids
Ceroid

localisation
–
places of erythrocytes destruction
–
necroses of adipous tissue
–
avitamonosis E
–
melanosis coli
–
Dubin - Johnson syndrome
Neuronal Ceroidlipofuscinoses
 neurodegenerative
disorders
characterized by accumulation of ceroid
lipopigment in lysosomes in various
tissues and organs.
 childhood forms - inherited in an AR
mode- five genes associated
 adult form of NCL – rare- AR, AD
Lipochrom




ubiquitous pigment
exogenous origin
lipid solvent
histologically unprovable
Lipofuscin

features
– dark brown
– Sudan +– autofluorescence
Lipofuscin
origin
– autophagocytosis
"wear and tear" pigment
from the accumulation
of autophagolysosomes over time.
Lipofuscin
localisation
–
CNS, epithels, muscles, liver
ATROPHIA FUSCA
Mitochondrial Damage and Intralysosomal
Degradation in Cellular Aging.
Terman A, Gustafsson B, Brunk UT.
Department of Pathology, University of Linkoping, Sweden
.
 mitochondrial
respiration - production of
superoxide and hydrogen peroxide
 minor macromolecular damage
 accumulation of biological "garbage" material
 neurons, cardiac myocytes and other long-lived
postmitotic cells affected
 lipofuscin-loaded lysosomes, in turn, poorly turn
over mitochondria
Mol Aspects Med. 2006 Oct-Dec;27(5-6):471-82.
Lipofuscin Pigment Can Be Used as a
Prognostic Marker in Prostatic
Adenocarcinoma.
„Lipofuscin in prostatic adenocarcinoma correlates
with both lower Gleason score and pathologic stage.
Lipofuscin probably indicates slow cellular turnover as
suggested by the low proliferation rate and p53
expression. The value of lipofuscin in biopsy as a
predictor separating aggressive from indolent disease
needs further investigation.“
Ann Diagn Pathol. 2006 Oct; 10(5)pp.257-62