Amyloidosis

covered most of amyloidosis

1. AMYLOIDOSIS Dr. Manoj Pant

2. Definition History Properties of amyloid proteins Classification Pathogenesis Morphology Clinicopathological classification Morphology of affected organs and clinical features Diagnosis Prognosis Layout

3. AMYLOIDOSIS Is a condition associated with inherited and inflammatory disorders in which There is deposition of Extracellular fibrillar proteins Tissue damage & functional compromise Aggregates of MISFOLDED proteins Insoluble

4. HISTORICAL ASPECTS “amylim” a latin word means “starch” Matthias Schleiden a German Botanist was the first to use the term “amyloid” in botany, for starch, referring to“starch-like”. German pathologist Rudolf Virchow in 1854 used the word “Amyloid” to describe some deposits in nervous system which showed the same color reaction with iodine and sulfuric acid, i.e. a change from brown to blue, typical to starch. In 1959 amyloid deposits were found to be composed of fibrils, other proteins and glycosoaminoglycans .

5. PROPERTIES OF AMYLOID PROTEINS

6. PHYSICAL NATURE Electron microscopy X-Ray crystallography & infrared spectroscopy All types of amyloid Continuous , non branching fibrils 7.5-10 nm in dia meter Cross beta pleated sheet conformation Responsible for distinctive congo red staining and birefr ingence

7. CHEMICAL NATURE 5% P FIBRILLARY PROTEINS Proteoglycans Glycosaminoglycans Serum Amyloid P etc. 95%

8. BIO CHEMICAL FORMS MAJOR AL Protein Highly sulfated glycosaminoglycans Transthyretin (TTR) β2-Microglobulin Serum Amyloid P ( SAP) Proteoglycans AA Protein A β Amyloid MINOR Prion proteins( APrP )

9. Complete Ig light chains (lambda/kappa light chain) /amino terminal fragment of light chains/both Secreted by monoclonal population of plasma cells Plasma cell tumors Non Immunoglobulin Derived from SAA protein which is synthesized from liver Acute phase protein Chronic i nflammation Derived from proteolysis of Amyloid precursor protein t ransmembrane g lycoprotein Alzheimer disease BIO CHEMICAL FORMS MAJOR AL Protein AA Protein A β Amyloid

10. Is a normal serum protein Mutant forms are deposited in familial amyloid polyneuropathies Normal form is deposited in heart of aged patients ( Senile cardiac Amyloidosis ) A normal serum protein Component of MHC class 1 A β2 - m - Amyloid fibril comp onent Long term hemodialysis BIO CHEMICAL FORMS MINOR Transthyretin (TTR) β2-Microglobulin Highly sulfated glycosaminoglycans Serum Amyloid P ( SAP) Proteoglycans Prion proteins( APrP )

11. PATHOGENESIS

12. Normal circumstances Misfolded proteins are degraded Intracellularly Extracellularly Amyloidosis Control mechanism fails Mutations which favor misfolding Proteasome pathway Macrophages Accumulation and Aggregation to form fibrils Abnormal folding of proteins/ Misfolded proteins Basic Mechanism

13. Normal proteins, when produced in abnormal numb ers Production of mutant proteins Acquired mutation Monoclonal B lymphocyte proliferation Immunoglobulin light chains Incomplete proteolysis AL protein Chronic Inflammation Macrophages activation IL1 &IL6 Increased SAA protein Incomplete proteolysis AA protein Eg : Transthyretin (TTR) Mutation Mutant TTR Aggregation ATTR protein PATHOGENESIS

14. MECHANISM OF DAMAGE TO THE TISSUES 1. Pressure effect: leading to atrophy 2. Accumulation in vessel wall : Leading to ischemia and also increased permeabi lity 3. Direct cytotoxicity: eg, Amyloidogenic light chain accumulation n cardiac cells 4. Prefibrillar oligomers: are found be more injurious than actual fibrils. In Alzheimer's and ATTR Amyloidosis

15. GENERALISED/SYSTEMIC AMYLOIDOSIS Familial Amyloidotic Neuropathy Transthyretin ATTR Systemic senile amyloidosis Transthyretin ATTR CATEGORY PRECURSOR PROTEIN FIBRIL PROTEIN ASSOCIATED DISEASES CLASSIFICATION (Based on the clinicopathologic features) Primary Amyloidosis ( immunocyte dyscrasias with amyloidosis Ig Light chains AL Multiple myeloma & other plasma cell dyscrasias Secondary Amyloidosis ( Reactive systemic amyloidosis SAA AA Chronic inflammation Hemodialysis associated Amyloidosis β2-microglobulin Aβ2-m Chronic renal failure LOCALISED AMYLOIDOSIS Senile cerebral APP Aβ Alzheimer disease Endocrine: Thyroid Calcitonin Acal Medullary Ca Thyroid Islet of Langerhans Islet Amyloid Peptide AIAPP Type 2 Diabetes HEREDITARY AMYOIDOSIS Familial Mediterranean fever SAA AA

16. Secondary Amyloidosis Rheumatoid arthritis, Ankylosing, spondylosis, inflammatory bowel diseases Drug abusers: Heroin injections… due to chronic skin infections Solid tumors : Renal cell carcinoma, Hodgkin lymphoma. REACTIVE SYSTEMIC AMYLOIDOSIS

17. Chronic renal failure β2-microglobulin is increased in the serum of these patients and gets Deposited in synovium, joints & tendon sheath β 2 - microg lobulin not filtered by dialysis membranes Hemodialysis associated Amyloidosis Deposition of A β2 microglobul in With recent advances and new dialysis filters the incidence has decreased.

18. Familial Amyloidotic Neuropathy Familial Mediterranean fever Heredofamilial amyloidosis Autosomal recessive Autoinflammatory syndrome Excessive production of IL1 in response to inflammation Characterized by attacks of fever with serosal inflammation Wide spread amyloidosis AA proteins Autosomal dominant Deposition of amyloid in peripheral and autonomic nerves Fibrils are made up of mutant TTRs

19. Limited to a single tissue or organ Can be only microscopic foci or may be evident grossly as nodular m asses The common sites: lung, larynx, skin, bladder, tongue etc. Microscopic findings: Lymphocytes and plasma cells can be seen in the periphery of amyloid deposits. Some cases , the amyloid consists of AL protein Localised amyloidosis

20. MORPHOLOGY OF AMYLOIDOSIS

21. GROSS EXAMINATION May or may not be visible If the deposits are too much, then the organ is enlarged, grey, waxy and firm.

22. MICROSCOPIC EXAMINATION Hematoxylin & Eosin Extrace llular Closely a djacent to basement membranes. With further accumulation , it encroaches on cells and destroy them Can be perivascular or vascular Amorphous, eosinophilic, glassy/hyaline . Should be differentiated from collagen, fibrin .

23. SPECIAL STAINS Congo Red Stain Ordinary light Amyloid appears red/pink Polarizing microscopy Apple Green Birefringence Cross beta pleated sheet conformation is the reason for this special staining property!

24. OTHER SPECIAL STAINS

25. 2. Methyl & Cresyl Violet Metachromatic stains, pink color

26. 3. ThioFlavin Exhibits Yellow Flouroscence

27. 4. Alcian Blue Stains blue, due to presence of glycosaminoglycans

28. 5. Immunohistochemistry: To distinguish AL, AA & ATTR types (A panel of antibodies against major amyloid fibril proteins)

29. AMYLOIDOIS O F DIFFERENT ORGANS

30. 1.KIDNEY • Most common • Most serious • Found most commonly in secondary amyloidosis . • Accounts for one third cases of primary amyloidosis

31. • Gross examination: • Can be normal size/ enlarged • may be contracted/shrunken (due to the narrowing of vessels resulting in ischemia) • Cut surface: Pale and waxy/ transluscent

32. Microscopy Can involve any part of kidney! But glomerular lesions predominates . Glomeruli: They appear as amorphous material in mesangium and capillary loops Tubules : deposits near basement membrane. Later seen in connective tissue between them/interstitium Vessels: deposits in the walls of arterioles leading to narrowing of lumen

33. Clinical features of Renal amyloidosis • Can present with proteinuria. • May be severe enough to result in Nephrotic syndrome Increased deposition in glomeruli and interstitium Glomerular ischemia and atrophy of tubules Chronic Renal failure

34. 2.LIVER Involved in most cases of systemic amyloidosis. Gross : Enlarged, pale & waxy

35. Microscopy Initially appears in space of Disse In between the cords of hepatocytes ( RIBBON like pink staining ) Shrunken /atrophic hepatocytes Compression of cords eosinophilic hyaline material (1) present within and between the hepatic tissue (2). There is marked distortion of lobular 

36. 3.SPLEEN Gross : Moderate to marked splenomegaly. Two patterns seen: Moderate enlargement. C/S: transluscent waxy nodules resembling sago grains Moderate to marked enlargement C/S: map like areas resembling La rd! LARDACEOUS SPLEEN/DIFFUSE SAGO SPLEEN /NODULAR SAGO SPLEEN /NODULAR

37. Microscopy Micro: involves periarteolar lymphoid sheath (white pulp) and hence they form discrete deposits Micro: Deposits start in the walls of splenic sinuses,which progresses till they form large diffuse masses. SAGO SPLEEN /NODULAR LARDACEOUS SPLEEN/DIFFUSE

38. 4.HEART Commonly associated with systemic amyloidosis Rarely as localized type ( Senile Cardiac Amyloidosis) Clinical Features : Can result in Cardiac Failure. Subendocardial deposition can interfere with conduction system leading to arrhythmias .

39. Gross : May be enlarged. Pale , translucent and waxy. Nodules/Plaques of amyloid can be seen in the epi/endocardium

40. Microscopically Seen in the coronary vessels or surrounding them. Around the myocardial fibes ( Ring Fibers). Left atrium/interatrial septum in Senile Cardiac Amyloidosis.

41. Other organs Brain- Alzheimer disease, amyloid plaques . Gastrointestinal tract - Malabsorption, diarrhea. Involvement of tongue can cause macroglossia. Respiratory tract involved focally or diffuse from larynx to bronchioles. Vascular amyloidosis- vascular fragility and increased bleeding tendency. Peripheral and autonomic nerves- Familial amyloidotic neuropathies Macroglossia Bleeding under the skin Amyloid plaques -Alzheimer disea se

42. DIAGNOSIS OF AMYLOIDOSIS D iagnosis of systemic amyloidosis is confirmed by tissue diagnosis/ histopathological examination. Abdominal fat pad aspiration is the preferred method for diagnosis. Rectal and Gingival biopsy or labial/salivary gland biopsy may be taken for systemic amyloidosis. Localised amyloidosis: biopsy of the involved tissue and confirmation by staining.

43. Immunohistochemistry the most commonly used method for amyloid typing . In suspected AL amyloidosis electrophoresis and immunoelectrophoresis .

44. Scintigraphy with radiolabelled serum amyloid (SAP-SERUM AMYLOID P component, I 123 labelled) – rapid and specific, measures the extent of amyloidosis. Technetium scan : Tc 99m pyrophosphate binds avidly to many types of amyloid -strongly positive in patients with severe disease. Recent advances in amyloidosis

45. PROGNOSIS Generalised /systemic amyloidosis: the prognosis is poor. Myeloma associated amyloidosis has poorer outcomes with median survival rates of 2years. Survival time depends on the type of predominantly involved organ. Cardiac involvement is the major determinant of survival prognosis – major cause of death.

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