Amyloidoisis

2. • Amyloidosis is a rare, serious condition
caused by a extracellular deposition of an
abnormal, insoluble fibrillar protein called
amyloid.
Such insoluble proteins gets
deposited in tissues causing
Tissue damage
Functional compromise

3. • Amyloids are aggregates of proteins that
become misfolded into a shape that allows
many copies of that protein to stick together,
forming fibrils

4. • The Word Amyloid means STARCH-LIKE (since
they stain with iodine just like Starch).
• Earlier it was thought as Starch, but in later
years it was chemically identified as Protein.
• Even though it was identified as Protein its
name Amyloid remained the same.

5. PROPERTIES OF AMYLOID PROTEINS
• More than 20 different types of Proteins can
aggregate to form fibrils.
• Although all these protein aggregates appear similar,
with regard to their nature they are different and
each kind of protein aggregate can cause different
disease.
• Eg:
- β – Amyloid causes Alzheimer's disease
- Apolipoprotein AI- causes atherosclerosis

6. PROPERTIES
1. PHYSICAL NATURE
2. CHEMICAL NATURE

7. 1. PHYSICAL NATURE

8. Cross-beta-pleated
sheet configuration

10. 2- CHEMICAL NATURE
FIBRIL PROTEINS-
95 %
NON-FIBRIL
PROTEINS-5 %
FIBRIL PROTEINS
NON-FIBRIL PROTEINS
Even though physically similar in appearance, chemically they are heterogeneous

11. 1. FIBRIL PROTEINS
• These proteins can be categorized as under:
FIBRIL
PROTEINS
AL (Amyloid
Light chain)
protein
AA (Amyloid
Associated)
protein
Other proteins- (β-
Amyloid proteins,
Transthyretin
proteins)
MAJOR FORMS
MINOR FORMS

12. AL PROTEIN AA PROTEIN
• derived from
immunoglobulin light
chain.
• produced by
immunoglobulin secreting
cells.
• seen in association with
Plasma Cell Dyscrasias /
Tumours / Multiple
Myeloma
• derived from Acute phase
reactant protein called
Serum Amyloid Associated
Protein (SAA).
• Seen in association with
Chronic inflammatory
conditions and
Autoimmune diseases.
MAJOR FORMS

13. β- Amyloid (Aβ) Amyloid Transthyretin
(ATTR)
Amyloid β2- Microglobulin
(Aβ2M)
• derived from the cell
surface protein
(Transmembrane
glycoprotein) called
Amyloid Precursor
Protein.
• seen in association
with Alzheimer's
disease
• derived from the serum
protein called
Transthyretin (TTR)
(which transports
thyroxine and retinol)
(trans-thy-retin).
• ATTR forms due to
mutation in genes coding
to TTR
•Seen in association with
familial Amyloid
polyneuropathies
• derived from MHC Class 1
protein molecules
•seen in cases of long-term
haemodialysis (for 10-12
years).
MINOR FORMS

14. 2. NON-FIBRILLAR PROTEINS
NON-FIBRILLAR
PROTEINS
AMYLOID P (AP)
APOLIPOPROTEINS
(apoE)
SULFATED
GLYCOSAMINOGLYCANS
(GAGS)
MINOR FORMS

15. PATHOGENESIS OF AMYLOIDOSIS

16. BASIC MECHANISM
Abnormal folding of proteins/ Misfolding of Proteins
In NORMAL CIRCUMSTANCES
Misfolded Proteins are degraded
by
BY
PROTEOSOME
PATHWAY
BY
MACROPHAGES
INTRACELLUARLY EXTRACELLUARLY
IN AMYLOIDOSIS
Misfolded Proteins are NOT degraded due
to FAILURE in control mechanisms leading
to aggregation of proteins forming fibrils

17. PATHOGENESIS OF NORMAL PROTEINS PRODUCED IN
ABNORMAL NUMBERS
AMYLOID LIGHT CHAIN PROTEIN (AL)
ABNORMAL B-LYMPHOCYTE PROLIFERATION
INCREASED PLASMA CELLS
INCREASED IMMUNOGLOBULINS LIGHT CHAINS
INCREASED IMMUNOGLOBULINS LIGHT CHAINS
AMYLOID LIGHT CHAIN PROTEINS (AL)
FAILURE in control mechanisms

18. AMYLOID ASSOCIATED (AA) PROTEIN
CHRONIC INFLAMMATION
IL-1, IL-6 PRODUCTION BY MACROPHAGES
INCREASED SERUM AMYLOID ASSOCIATED PROTEIN
FORMATION OF AMYLOID ASSOCIATED PROTEIN
FAILURE in control mechanisms

19. • Sometimes mutation of some proteins like TTR
(Transthyretin) leads to formation of MUTANT
FORM OF TTR i.e., ATTR.
• Such proteins are resistant to degradation and
gets accumulated in tissues.
PATHOGENESIS OF ABNORMAL MUTATED PROTEINS PRODUCED
IN NORMAL NUMBERS

20. CLASSIFICATION OF AMYLOIDOSIS

21. • Over the years, amyloidosis has been
classified in a number of ways.
• However clinicopathologic classification is
widely accepted

22. CLINICOPATHOLOGIC CLASSIFICATION
CATEGORY PRECURSOR
PROTEIN
FIBRIL
PROTEIN
ASSOCIATED
DISSEASES
1. GENERALISED/SYSTEMIC AMYLODOSIS
PRIMARY AMYLOIDOSIS Ig Light Chains AL MULTIPLE MYELOMA
SECONDARY AMYLOIDOSIS
(REACTIVE SYSTEMIC
AMYLOIDOSIS)
SAA AA CHRONIC
INFLAMMATION
HEMODIALYSIS ASSOCIATED
AMYLOIDOSIS
β2- microglobulin Aβ2M CHRONIC RENAL
FAILURE
2. LOCALISED AMYLOIDOSIS
SENILE CEREBRAL
AMYLOIDOSIS
APP Aβ ALZEMIERS DISEASE
SENILE CARDIAC AMYLOIDOSIS TTR ATTR SENILITY

23. CATEGORY PRECURSOR
PROTEIN
FIBRIL PROTEIN ASSOCIATED
DISSEASES
ENDOCRINE AMYLOIDOSIS
THYROID
ISLET OF LANGERHANS
CALCITONIN
ISLET AMYLOID
PEPTIDE
Acal
AIAPP
Medullary carcinoma
of Thyroid.
TYPE-2 DIABETES
3. HEREDITARY AMYLOIDOSIS
FAMILIAL MEDITERRIAN FEVER SAA AA
FAMILIAL AMYLOIDOTIC
NEUROPATHY
TTR ATTR

24. SYSTEMIC AMYLOIDOSIS

25. REACTIVE SYSTEMIC AMYLOIDOSIS/SECONDARY AMYLOIDOSIS
• It is secondary to chronic inflammatory diseases.
• Fibril proteins are AA amyloid.
Diseases where it is seen:
Earlier common in TUBERCULOSIS,
BRONCHIECTASIS, CHRONIC
OSTEOMYELITIES
Presently common in RHEUMATOID
ARTHRITIS, ANKYLOSING
SPONDYLOSIS, IBD
Also common in Drug abusers-
heroin injections.
Tumors: RENAL CELL CARCINOMA,
HODGKIN LYMPHOMA,

26. Secondary Amyloidosis is typically distributed:
 in solid abdominal viscera like the
- kidney,
- liver,
- spleen and
- adrenals.
• Secondary reactive amyloidosis is seen less frequently
in developed countries, but this is the more common
type of amyloidosis in under developed and developing
countries of the world.
• Can occur at any age.
• Is the only form of amyloid which can occur in
children.

27. Primary Systemic (AL) Amyloidosis
• It is associated with Plasma cell dyscrasias like
MULTIPLE MYELOMA.
• Neoplastic plasma cells produce
immunoglobulin light chains or part of light
chain.
• These light chains clump together to form
Fibril proteins called AL amyloid.
• Abnormal light chains in urine are sometimes
referred to as "Bence Jones protein".

28. In multiple myeloma, the type of light chains
which form Amyloid fibrils are- λ (lambda) or κ
(kappa) chains

29. Signs and Symptoms of Primary amyloidosis
• More common in DEVELOPED COUNTRIES
• AL amyloidosis can affect a wide range of organs
• The kidneys are the most commonly affected organ in AL amyloidosis.
• Symptoms of kidney disease and kidney failure can include fluid
retention, swelling, and shortness of breath.
• In addition to kidneys, AL amyloidosis may affect the heart, peripheral
nervous system, gastrointestinal tract, blood, lungs and skin.
• Heart complications include heart failure and irregular heart beat.
Other complications:
• Stroke,
• Enlarged liver,
• Diminished spleen function,
• Diminished function of the adrenal
• Bleeding and bruising problems,
• Fatigue, and weight loss

31. STAINING CHARACTERISTICS OF AMYLOID
• 1. STAIN ON GROSS
• The oldest method since the time of Virchow for
demonstrating amyloid on cut surface of a gross specimen, or
on the frozen/paraffin section is iodine stain.
• Iodine imparts mahogany brown colour to the amyloid
containing area which on addition of dilute sulfuric acid turns
blue.
mahogany brown colour

32. 2. H & E STAIN:
• Amyloid by light microscopy with haematoxylin and
eosin staining appears as extracellular,
homogeneous, structureless and eosinophilic hyaline
material.

33. 3. METACHROMATIC STAINS (ROSANILINE DYES)
• Amyloid has the property of metachromasia i.e. the
dye reacts with amyloid and undergoes a colour
change.
• Metachromatic stains employed are rosaniline dyes
such as methyl violet and crystal violet which impart
rose-pink colouration to amyloid deposits.

34. 4. CONGO RED AND POLARISED LIGHT:
• All types of amyloid have affinity for Congo red
stain; therefore this method is used for confirmation
of amyloid of all types.
• The stain may be used on both gross specimens and
microscopic sections; amyloid of all types stains pink
red colour

35. 5. FLUORESCENT STAINS:
• Fluorescent stain thioflavin-T binds to amyloid
and fluoresces yellow under ultraviolet light.

36. MORPHOLOGIC FEATURES OF AMYLOIDOSIS OF ORGANS
AMYLOIDOSIS OF SPLEEN
Amyloid deposition in the spleen, for some unknown
reasons, may have one of the following two patterns:
1. SAGO SPLEEN
• Grossly, splenic enlargement is not marked and cut
surface shows characteristic translucent pale and
waxy nodules resembling sago grains and hence the
name.
• Microscopically, the amyloid deposits begin in the
walls of the arterioles of the white pulp and may
subsequently extend out and replace the follicles.

37. SAGO SPLEEN

38. 2. LARDACEOUS SPLEEN
• Grossly, there is generally moderate to marked
splenomegaly (weight up to 1 kg).
• Cut surface of the spleen shows map-like areas of
amyloid (lardaceous-lard-like; lard means fat of
pigs)
• Microscopically, the deposits involve the red pulp
in the walls of splenic sinuses and the small
arteries and in the connective tissue .
• Confirmation is by observing Congophilia in
Congo red staining and demonstration of apple-
green birefringence under polarising microscopy
in the corresponding positive areas.

40. 2. AMYLOIDOSIS OF KIDNEYS
• Amyloidosis of the kidneys is most common and
most serious because of ill-effects on renal function.
• The deposits in the kidneys are found in most cases
of secondary amyloidosis and in about one-third
cases of primary amyloidosis.
• Even small quantities of amyloid deposits in the
glomeruli can cause proteinuria and nephrotic
syndrome.