[Interdisciplinary guidelines on diagnosis and treatment for extracerebral amyloidoses--published by the German Society of Amyloid Diseases (www.amyloid.de)]

[Renal manifestations in rheumatoid arthritis and spondylarthritis]

As systemic diseases it is not uncommon for inflammatory rheumatic diseases to exhibit renal involvement. In contrast to connective tissue diseases and vasculitis, in rheumatoid arthritis and spondylarthritis direct inflammatory manifestations in the sense of glomerulonephritis (GN) and autoimmune interstitial nephritis are rare. In these groups of diseases renal biopsies usually show mesangial proliferative GN and IgA nephropathy or less commonly membranous GN. These and secondary amyloid A (AA) amyloidosis are regularly associated with longer lasting disease activity and a poor prognosis; however, clinically more frequent and more relevant are other sequelae of chronic systemic inflammation, namely endothelial function disorder and the premature development of atherosclerosis, resulting in progressive kidney failure. This is accompanied by the undesired effects of antirheumatic treatment and renal complications of comorbidities.

Amyloid in biopsies of the gastrointestinal tract-a retrospective observational study on 542 patients

In this retrospective observational study, we investigated the histopathological and demographic characteristics of amyloid in gastrointestinal biopsies. From the Amyloid Registry Kiel, we retrieved all cases with amyloid in biopsies of the stomach, duodenum, small intestine, large intestine, and rectum submitted for tertiary referral between January 2003 and April 2013. Amyloid was identified by Congo red staining in combination with polarization microscopy and classified by immunohistochemistry. The TTR-genotype was assessed in 56 patients. Amyloid type was correlated with demographic patient characteristics. Six hundred sixty-three biopsies from 542 patients were retrieved. Amyloid was found in each biopsy as vascular and/or interstitial amyloid deposits. Biopsies were obtained from the colon [254 biopsies (38.3 %)], stomach, [153 (23.1 %)], rectum [112 (16.9 %)], duodenum [105 (15.8 %)], and jejunum/ileum [39 (5.9 %)]. ALλ amyloid was found in 286 (52.8 %), ATTR in 88 (16.2 %), ALκ in 74 (13.7 %), AA in 58 (10.7 %), and ApoAI amyloid in 4 (0.7 %) patients. The remaining 21 cases were ALys amyloid in 4 (0.7 %), AL n.o.s. in 14 (2.6 %), and mixed type amyloidosis in 3 (0.6 %). The amyloid of 11 (2.0 %) cases remained unclassified. The median age of the patients was 68 years. Men [332 (61.7 %)] were significantly more prevalent than women [206 (38.3 %); p < 0.001]. TTR mutations were found in 24 % of the patients with ATTR amyloidosis. The median age, the histoanatomical distribution (proximal to distal; mucosal to submucosal), and the deposition pattern (vascular/interstitial) varied between different amyloid types. Amyloid in gastrointestinal biopsies mainly affects male elderly patients and shows amyloid-type-specific demographic patient characteristics.

Amyloid arthropathy associated with multiple myeloma: a systematic analysis of 101 reported cases

OBJECTIVE

Amyloid deposition in multiple myeloma (MM) may lead to an arthropathy resembling rheumatoid arthritis (RA). Since a systematic description of its natural history is lacking, we have performed a systematic analysis of all published cases.

METHODS

Literature review featuring backward and forward database searches and direct inspection of reference lists. Inclusion criteria were as follows: publication between 1931 and 2012, diagnosis of multiple myeloma, and demonstration of light chain amyloid (AL) in any organ or in synovial fluid, arthritis, or synovitis.

RESULTS

Overall, 101 cases were identified. Median age was 59 years and the male-to-female ratio was 1:1. A systemic manifestation of MM was reported in 88 cases. In 53 of these, characteristic physical findings (carpal tunnel syndrome, macroglossia, shoulder pad, and soft tissue swelling/masses) were present. Arthritis manifested before the diagnosis of MM in 63 cases, with 33 cases initially misdiagnosed as RA. There were 72 cases of poly-, 17 of oligo-, and three of monoarthritis. The shoulder joint was most commonly affected, followed by knees and small hand joints. Median synovial fluid leukocyte count was 2460 cells/mm(3), and was normal in seven cases. Synovial histopathology often featured mild synovitis without plasma cell infiltration. Imaging revealed articular or periarticular inflammation in many cases and bone lesions near 22% of affected joints. Treatments varied but led to some improvement in the majority of cases.

CONCLUSIONS

These results solidify previous experience that MM arthropathy tends to feature a symmetric RF-negative nonerosive polyarthritis. However, the results also highlight the diversity of its presentations and stress the importance of arthropathy as a potentially under-recognized presenting manifestation of MM.

[Amyloidosis of the heart]

Amyloidosis is a heterogeneous group of diseases characterized by the pathological deposition of autologous proteins in an antiparallel β-sheet confirmation forming non-branching linear fibrils of indefinite length and an approximate diameter of 10-12 nm. Cardiac amyloidosis is caused by deposits in the heart and may lead to cardiac arrhythmia and low output failure. Following the diagnosis, classification of the amyloid protein and evaluation of further organ involvement is mandatory. Treatment approaches are based on reduction of the production of amyloid precursor proteins. Standard heart failure treatment is usually not well tolerated and the underlying disease remains unaffected. Cardiac amyloidosis, especially of the light chain type, is associated with a poor outcome. The clinical picture is uncharacteristic, therefore correct diagnosis of cardiac amyloidosis is often delayed in many patients. Combination of clinical symptoms of different organ systems should alert the physician to the diagnosis of amyloidosis.

[Amyloidosis in liver biopsies]

INTRODUCTION

We reassessed the histopathology and origin of amyloid in liver biopsies.

MATERIALS AND METHODS

All liver biopsies were retrieved from a series of 588 cases with histologically confirmed amyloidosis submitted between February 2006 and January 2009 to the Amyloid Registry of the Charité University Hospital. Liver biopsies had been fixed in formalin and embedded in paraffin. 3-5 microm thick paraffin sections were stained with hematoxylin and eosin and Congo red. Amyloid was classified immunohistochemically, using antibodies directed against amyloid P-component, AA amyloid, apolipoprotein AI, fibrinogen, lysozyme, lambda- and kappa-light chain, and transthyretin.

RESULTS

Amyloid was found in 46 liver biopsies (29 men, 17 women; mean age 60 years, range 34-87 years). Immunohistochemical classification succeeded in 42 cases. AL amyloidosis was present in 40 (87%) cases and was further categorized into AL amyloid of lambda-light chain origin in 26 (57%) cases, and kappa-light chain origin in 14 (30%) cases. ATTR and AA amyloidosis were found in a single patient each (2%). In 4 (9%) cases, amyloid remained unclassified.

CONCLUSIONS

Hepatic amyloidosis is most commonly AL amyloid of lambda- and kappa-light chain origin and is often associated with marked parenchymal atrophy.

[Amyloid and amyloidoses]

Amyloid is a pathologic fibrillar aggregation of polypeptides in a cross-beta-sheet conformation. Amyloidoses are caused by the deposition of amyloid and may occur as cerebral and extracerebral disease. More than 29 different amyloid proteins have been identified. Analysis of a Congo red-stained tissue section by polarization microscopy is the gold standard for diagnosing amyloid. Subsequent classification of the amyloid is mandatory and is increasingly supported by molecular biological analyses. In Germany, this recently led to the discovery of several hereditary amyloid diseases. The correct classification of amyloid is of paramount importance. This helps to asses the prognosis and plan patient treatment.

[Amyloidoses in the Berlin Museum of Medical History of the Charité]

The Berliner Medizinhistorische Museum (Berlin Museum of Medical History) of the Charité is located in its own separate building and was officially opened in 1899. It currently houses 10,000 specimens, of which 23 were labelled with the diagnosis "amyloid" or "amyloidosis". In this retrospective study we aimed to histologically verify the diagnosis, classify the amyloid deposits immunohistochemically and correlate the type of amyloid with clinico-pathological data. The specimens were obtained between 1866 and 1987 and included 17 kidneys, five spleens and one liver. The diagnosis could be confirmed histologically using Congo red staining and polarization microscopy in 22 specimens. However, the diagnosis could not be confirmed in the oldest specimen, which had been labelled by Rudolf Virchow himself. Immunohistochemically amyloid was classified as either AA amyloidosis (19 cases) or AL amyloidosis (two cases). Tuberculosis was the most common cause of AA amyloidosis. This study shows that a surgical pathological re-evaluation of historical specimens can verify the original diagnosis. This is historically fascinating and also offers a valuable addition to student teaching.

Transthyretin valine-94-alanine, a novel variant associated with late-onset systemic amyloidosis with cardiac involvement

A 63-year-old Caucasian male, diagnosed with dilated cardiomyopathy in 1993, remained clinically stable for several years. In 2003, a marked increase of N-terminal pro-natriuretic peptide serum level (611 ng/ml to 4926 ng/ml) was observed; left ventricular (LV) septum thickness was 10 mm. In addition, sensorimotor polyneuropathy and autonomic dysfunction occurred. Further progression of heart failure occurred despite unchanged systolic LV function. Endomyocardial biopsy in 2006 revealed transthyretin amyloidosis by Congo red and immunohistochemical staining, as well as Val94Ala substitution by transthyretin gene analysis. Cardiac amyloid deposition was quantified by technetium-99m-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) scintigraphy. Mutational search of the relatives (n = 1) was unremarkable. The transthyretin Val94Ala mutation is characterized by sensorimotor polyneuropathy, autonomic dysfunction, and gastrointestinal and cardiac involvement with amyloid. This mutation is an addition to the growing spectrum of transthyretin mutations with late onset of clinical symptoms, but noteworthy because of progressive, finally disabling disease course. Final clinical assessment of severity of cardiac involvement in the present patient is rendered complex by possible concomitant or preceding idiopathic dilated cardiomyopathy.

Directed selection of a conformational antibody domain that prevents mature amyloid fibril formation by stabilizing Abeta protofibrils

The formation of amyloid fibrils is a common biochemical characteristic that occurs in Alzheimer's disease and several other amyloidoses. The unifying structural feature of amyloid fibrils is their specific type of beta-sheet conformation that differentiates these fibrils from the products of normal protein folding reactions. Here we describe the generation of an antibody domain, termed B10, that recognizes an amyloid-specific and conformationally defined epitope. This antibody domain was selected by phage-display from a recombinant library of camelid antibody domains. Surface plasmon resonance, immunoblots, and immunohistochemistry show that this antibody domain distinguishes Abeta amyloid fibrils from disaggregated Abeta peptide as well as from specific Abeta oligomers. The antibody domain possesses functional activity in preventing the formation of mature amyloid fibrils by stabilizing Abeta protofibrils. These data suggest possible applications of B10 in the detection of amyloid fibrils or in the modulation of their formation.

Effect of Different Salt Ions on the Propensity of Aggregation and on the Structure of Alzheimer’s Aβ(1-40) Amyloid Fibrils

The formation of amyloid fibrils and other polypeptide aggregates depends strongly on the physico-chemical environment. One such factor affecting aggregation is the presence and concentration of salt ions. We have examined the effects of salt ions on the aggregation propensity of Alzheimer's Abeta(1-40) peptide and on the structure of the dissolved and of the fibrillar peptide. All salts examined promote aggregation strongly. The most pronounced effect is seen within the cationic series, i.e. for MgCl2. Evaluation of different possible explanations suggests that Abeta(1-40) aggregation depends on direct interaction between ions and Abeta(1-40) peptide, and correlates with ion-induced changes of the surface tension. Salts have profound effects on the fibril structure. In the presence of salts, fibrils are associated with smaller diameters, narrower crossover distances and lower amide I maxima. Since Abeta(1-40) aggregation responds to salts in a manner unlike that for other polypeptides, such as glucagon, beta2-microglobulin or alpha-synuclein; these data argue that there is no fully uniform way in which salts affect aggregation of different polypeptide chains. These observations are important for understanding and predicting aggregation on the basis of simple physico-chemical properties.

[Amyloid diagnostics in rheumatic diseases]

Amyloid is a pathological protein deposit in tissue which has a red eosin color when the slice preparation is stained with traditional hematoxylin and eosin and after Congo red staining under polarized light exhibits a characteristic apple-green polarization color. Over 26 different autologous physiological proteins have been described that can form amyloid. In surgical pathology, immunoglobulin light chain-associated AL amyloidosis is the most frequent generally occurring amyloidosis, followed by hereditary and nonhereditary ATTR amyloidosis and AA amyloidosis. AA amyloidosis mostly develops subsequent to chronic infectious or inflammatory underlying disease and can represent a potentially life threatening complication. The spectrum of causes for AA amyloidosis has changed in the past few decades and is now determined by chronic rheumatic diseases and hereditary periodic fever syndromes. Early diagnosis of an amyloidosis and its correct classification continue to pose a great challenge. Precise classification of the amyloid and amyloidosis is essential for prognosis assessment and treatment planning. In addition to anti-inflammatory management of AA amyloidosis, specific treatment strategies may possibly become available in the future.