Where has secondary amyloid gone?

Characteristics and course of patients with AA amyloidosis: single centre experience with 174 patients from Turkey

OBJECTIVES

This study aimed to evaluate the clinical, laboratory and genetic characteristics and outcomes of patients with AA amyloidosis.

METHODS

Patients followed up in a tertiary referral centre in Turkey with the diagnosis of inflammatory rheumatic diseases and immunohistologically proven AA amyloidosis were included in the study and retrospectively analysed.

RESULTS

Among 184 patients with the diagnosis of AA amyloidosis, 174 (83 female, 91 male) were included in the analysis. The most common cause of AA amyloidosis was FMF (78.7%), and 91% of FMF-AA amyloidosis patients were carrying the p.M694V variant (74.1% homozygous). AA amyloidosis was identified earlier in patients with homozygous or compound heterozygous MEFV exon 10 variants compared with the heterozygous patients (27, 30 and 41 years, respectively). Patients with an estimated glomerular filtration rate <60 ml/min at admission had a higher frequency of progression to end-stage renal disease (P < 0.001). The overall mortality rate was 15.3% and it increased gradually in association with the amyloid burden (10% in patients with renal, 15% in renal + gastrointestinal and 43% in those with additional cardiac involvement). Renal findings responded completely to treatment in 31% of the patients, a partial response was observed in 4%, a stable course in 23.6% and progression in 38.5%. Amyloid storm was identified in nine patients and was found to be associated with increased mortality within 1 year.

CONCLUSION

FMF patients still constitute the majority of AA amyloidosis patients in Turkey. The MEFV genotype and associated inflammatory load may affect the age of onset of AA amyloidosis, and earlier diagnosis and stricter follow-up and treatment may delay progression of the disease.

Course and Prognosis of AA Amyloidosis in Patients with Psoriatic Arthritis: Report of Three Cases from a Single Center Cohort and Review of the Literature

Objective

Herein, we aimed to evaluate the frequency and clinical features of AA amyloidosis in patients with PsA followed up in our tertiary referral clinic.

Methods

We retrospectively evaluated PsA patients classified according to CASPAR classification criteria followed-up in our tertiary referral clinic for AA amyloidosis. The literature search was also done by three independent researchers using the keywords "psoriatic arthritis AND amyloidosis", "spondyloarthritis AND amyloidosis", "AA amyloidosis", "secondary amyloidosis".

Results and conclusions

A total of 253 patients were included into the analysis. Two thirds of (n=162; 64%) the patients were women, and the mean age of the patients was 50.6 ± 13.4 (range, 20-90). We identified three patients with AA amyloidosis in 253 patients with PsA (1.2 %). The frequency of PsA-related amyloidosis in our AA amyloidosis cohort (n=165) was 1.8 %. Literature search revealed only a retrospective cohort study and 17 case reports, and we analysed these 31 cases. Nearly half of the cases were male, mean age of the patients was 50.7±15.3 and mean age of amyloidosis diagnosis was 47.2±16.7 years. Most of these patients had both polyarticular and axial involvement (81.3%). AA amyloidosis is a rare in patients with PsA. It should be kept in mind that patients with PsA who have not received appropriate treatment for a long time and/or have refractory disease may develop AA amyloidosis.

Tissue-based diagnosis of systemic amyloidosis: Experience of the informal diagnostic center at Uppsala University Hospital

Diagnosis of systemic amyloidosis is a clinical challenge and usually relies on a tissue biopsy. We have developed diagnostic methods based on the presence of amyloid deposits in abdominal subcutaneous fat tissue. This tissue is also used to determine the biochemical type of amyloidosis, performed by western blot and immunohistochemical analyses with the aid of in-house developed rabbit antisera and mouse monoclonal antibodies. Mass spectrometric methods are under development for selected cases. The diagnostic outcome for 2018-2020 was studied. During this period, we obtained 1,562 biopsies, of which 1,397 were unfixed subcutaneous fat tissue with varying degrees of suspicion of systemic amyloidosis. Of these, 440 contained amyloid deposits. The biochemical nature of the amyloid was determined by western blot analysis in 319 specimens and by immunohistochemistry in further 51 cases.

Immunohistochemical typing of amyloid in fixed paraffin-embedded samples by an automatic procedure: Comparison with immunofluorescence data on fresh-frozen tissue

Amyloidosis comprises a spectrum of disorders characterized by the extracellular deposition of amorphous material, originating from an abnormal serum protein. The typing of amyloid into its many variants represents a pivotal step for a correct patient management. Several methods are currently used, including mass spectrometry, immunofluorescence, immunohistochemistry, and immunogold labeling. The aim of the present study was to investigate the accuracy and reliability of immunohistochemistry by means of a recently developed amyloid antibody panel applicable on fixed paraffin-embedded tissues in an automated platform. Patients with clinically and pathologically proven amyloidosis were divided into two cohorts: a pilot one, which included selected amyloidosis cases from 2009 to 2018, and a retrospective one (comprising all consecutive amyloidosis cases analyzed between November 2018 and May 2020). The above-referred panel of antibodies for amyloid classification was tested in all cases using an automated immunohistochemistry platform. When fresh-frozen material was available, immunofluorescence was also performed. Among 130 patients, a total of 143 samples from different organs was investigated. They corresponded to 51 patients from the pilot cohort and 79 ones from the retrospective cohort. In 82 cases (63%), fresh-frozen tissue was tested by immunofluorescence, serving to define amyloid subtype only in 30 of them (36.6%). On the contrary, the automated immunohistochemistry procedure using the above-referred new antibodies allowed to establish the amyloid type in all 130 cases (100%). These included: ALλ (n = 60, 46.2%), ATTR (n = 29, 22.3%), AA (n = 19, 14.6%), ALκ (n = 18, 13.8%), ALys (n = 2, 1.5%), and Aβ₂M amyloidosis (n = 2, 1.5%). The present immunohistochemistry antibody panel represents a sensitive, reliable, fast, and low-cost method for amyloid typing. Since immunohistochemistry is available in most pathology laboratories, it may become the new gold standard for amyloidosis classification, either used alone or combined with mass spectrometry in selected cases.

A new era of amyloidosis: the trends at a major US referral centre

Objective: To characterize the changing spectrum of amyloidosis classes, as well as patient demographics, at a major US referral centre. Patients and methods: A retrospective analysis was conducted of all referrals to the Amyloidosis Centre at Boston University and Boston Medical Centre over the last 3 decades. Results: A total of 3987 new patients with amyloidosis were evaluated between 1990 and 2018 with the average number of new cases per year increasing 2.5-fold during this period. Systemic immunoglobulin light-chain (AL) amyloidosis decreased in proportion with each decade from 77% to 69% to 50% of new cases. Meanwhile, ATTR amyloidosis increased from 12% to 16% to 29%, predominately due to more diagnosis of ATTRwt and ATTRV122I amyloidosis. Gender and race profile differences, while changing over the observed time period, persisted among amyloidosis patients. Conclusion: Amyloid diseases are more widely recognized and classes of amyloidosis, including ATTRwt and ATTRV122I, once considered rare are now increasingly diagnosed. These data likely reflect a national trend of increased amyloidosis awareness facilitated by accessible diagnostic approaches, emerging treatments, and coordinated educational initiatives. ClinicalTrials.gov identifier: NCT00898235.

Apolipoprotein A-II induces acute-phase response associated AA amyloidosis in mice through conformational changes of plasma lipoprotein structure

During acute-phase response (APR), there is a dramatic increase in serum amyloid A (SAA) in plasma high density lipoproteins (HDL). Elevated SAA leads to reactive AA amyloidosis in animals and humans. Herein, we employed apolipoprotein A-II (ApoA-II) deficient (Apoa2 ^-/- ) and transgenic (Apoa2Tg) mice to investigate the potential roles of ApoA-II in lipoprotein particle formation and progression of AA amyloidosis during APR. AA amyloid deposition was suppressed in Apoa2 ^-/- mice compared with wild type (WT) mice. During APR, Apoa2 ^-/- mice exhibited significant suppression of serum SAA levels and hepatic Saa1 and Saa2 mRNA levels. Pathological investigation showed Apoa2 ^-/- mice had less tissue damage and less inflammatory cell infiltration during APR. Total lipoproteins were markedly decreased in Apoa2 ^-/- mice, while the ratio of HDL to low density lipoprotein (LDL) was also decreased. Both WT and Apoa2 ^-/- mice showed increases in LDL and very large HDL during APR. SAA was distributed more widely in lipoprotein particles ranging from chylomicrons to very small HDL in Apoa2 ^-/- mice. Our observations uncovered the critical roles of ApoA-II in inflammation, serum lipoprotein stability and AA amyloidosis morbidity, and prompt consideration of therapies for AA and other amyloidoses, whose precursor proteins are associated with circulating HDL particles.

Clinical, Epidemiological, and Histopathological Features of Respiratory Involvement in Rheumatoid Arthritis

Although by definition rheumatoid arthritis (RA) is an articular disorder, it is a systemic disease, and 18–40% of patients experience extra-articular manifestations (EAMs). The involvement of the respiratory system occurs in about 30–40% of RA patients, and in about 10–20% of them it represents the first manifestation of RA. A wide range of pulmonary manifestations are detectable in RA patients, including pulmonary parenchymal disease, pleural involvement, and airway and pulmonary inflammation. The clinical, radiological, and histological spectra of respiratory manifestations in RA reflect chronic immune activation, increased susceptibility to infection (often related to immunosuppressive medications), or direct drug. The type and severity of pulmonary involvement influence the prognosis, ranging from mild self-limiting conditions to severe life-threatening complications. Herein, we reviewed the various manifestations of respiratory involvement in RA, providing an overview on epidemiological, histological, clinical, and radiological data.

Systemic AA amyloidosis in the red fox (Vulpes vulpes)

Amyloid A (AA) amyloidosis occurs spontaneously in many mammals and birds, but the prevalence varies considerably among different species, and even among subgroups of the same species. The Blue fox and the Gray fox seem to be resistant to the development of AA amyloidosis, while Island foxes have a high prevalence of the disease. Herein, we report on the identification of AA amyloidosis in the Red fox (Vulpes vulpes). Edman degradation and tandem MS analysis of proteolyzed amyloid protein revealed that the amyloid partly was composed of full-length SAA. Its amino acid sequence was determined and found to consist of 111 amino acid residues. Based on inter-species sequence comparisons we found four residue exchanges (Ser31, Lys63, Leu71, Lys72) between the Red and Blue fox SAAs. Lys63 seems unique to the Red fox SAA. We found no obvious explanation to how these exchanges might correlate with the reported differences in SAA amyloidogenicity. Furthermore, in contrast to fibrils from many other mammalian species, the isolated amyloid fibrils from Red fox did not seed AA amyloidosis in a mouse model.

Long-term follow-up of secondary amyloidosis patients treated with tumor necrosis factor inhibitor therapy: A STROBE-compliant observational study

There are no treatment modalities, which were proven to prevent the deposition of amyloid, proteinuria, and loss of renal function due to amyloidosis. Anti-tumor necrosis factor agents (anti-TNFs) were shown to decrease the production of serum amyloid A protein.We aimed to evaluate the long-term efficacy and safety of anti-TNFs in secondary (AA) amyloidosis patients treated in a single center.Thirty-seven patients with AA amyloidosis were started an anti-TNF for AA amyloidosis between March 2001 and June 2008 and followed until May 2016 unless deceased. They were surveyed for the endpoints of death, development of end-stage renal disease (ESRD), switch to another agent due to worsening of amyloidosis and adverse events.Among the 37 patients, 12 (32%) had died, 9 (24%) had ESRD, and 8 (22%) had started another group of biologic due to worsening of amyloidosis indicated by an increase in proteinuria, 5 (14%) patients are still doing well with anti-TNFs, and 3 (8%) are off treatment at the end of a median follow-up of 10 (interquartile range [IQR]: 5.5-10.5) years since the start of anti-TNFs and 10 (IQR: 8-13) years since the diagnosis of AA amyloidosis. Most common serious adverse events were sepsis and thrombotic events observed in 8 and 4 patients, respectively.Treatment with anti-TNFs may be associated with a higher survival rate compared with historic cohorts of AA amyloidosis, especially when started early with a lower serum creatinine level at baseline. Caution is needed regarding serious adverse events, especially infections.

Cell-to-cell transfer of SAA1 protein in a cell culture model of systemic AA amyloidosis

Systemic AA amyloidosis arises from the misfolding of serum amyloid A1 (SAA1) protein and the deposition of AA amyloid fibrils at multiple sites within the body. Previous research already established that mononuclear phagocytes are crucial for the formation of the deposits in vivo and exposure of cultures of such cells to SAA1 protein induces the formation of amyloid deposits within the culture dish. In this study we show that both non-fibrillar and fibrillar SAA1 protein can be readily transferred between cultured J774A.1 cells, a widely used model of mononuclear phagocytes. We find that the exchange is generally faster with non-fibrillar SAA1 protein than with fibrils. Exchange is blocked if cells are separated by a membrane, while increasing the volume of cell culture medium had only small effects on the observed exchange efficiency. Taken together with scanning electron microscopy showing the presence of the respective types of physical interactions between the cultured cells, we conclude that the transfer of SAA1 protein depends on direct cell-to-cell contacts or tunneling nanotubes.

[Pathological and clinical correlations in renal AA amyloidosis: A Moroccan series of 30 cases]

OBJECTIVE

Study of histological and clinical correlations of 30 cases of renal amyloidosis AA diagnosed between November 2010 and December 2012.

RESULTS

The main causes associated with amyloidosis AA were represented by chronic infectious diseases (60%). Nephrotic syndrome and renal failure were observed in 94% and 73% respectively. The distribution of amyloid deposits: 90% of patients had a glomerular form and 10% had a vascular form. Inflammatory reaction associated with AA renal amyloidosis was present in 50% of cases. This inflammation was observed near amyloid deposits associated with a deposition of immunoglobulin chains and/or complement factors.

CONCLUSION

Our study confirms the predominance of AA amyloidosis complicating chronic infectious diseases, especially tuberculosis. Our data point out a relationship between the morphology of renal AA amyloidosis, its clinical presentation and prognosis.

Intrinsic Stability, Oligomerization, and Amyloidogenicity of HDL-Free Serum Amyloid A

Serum amyloid A (SAA) is an acute-phase reactant protein predominantly bound to high-density lipoprotein in serum and presumed to play various biological and pathological roles. Upon tissue trauma or infection, hepatic expression of SAA increases up to 1,000 times the basal levels. Prolonged increased levels of SAA may lead to amyloid A (AA) amyloidosis, a usually fatal systemic disease in which the amyloid deposits are mostly comprised of the N-terminal 1-76 fragment of SAA. SAA isoforms may differ across species in their ability to cause AA amyloidosis, and the mechanism of pathogenicity remains poorly understood. In vitro studies have shown that SAA is a marginally stable protein that folds into various oligomeric species at 4 °C. However, SAA is largely disordered at 37 °C, reminiscent of intrinsically disordered proteins. Non-pathogenic murine (m)SAA2.2 spontaneously forms amyloid fibrils in vitro at 37 °C whereas pathogenic mSAA1.1 has a long lag (nucleation) phase, and eventually forms fibrils of different morphology than mSAA2.2. Remarkably, human SAA1.1 does not form mature fibrils in vitro. Thus, it appears that the intrinsic amyloidogenicity of SAA is not a key determinant of pathogenicity, and that other factors, including fibrillation kinetics, ligand binding effects, fibril stability, nucleation efficiency, and SAA degradation may play key roles. This chapter will focus on the known structural and biophysical properties of SAA and discuss how these properties may help better understand the molecular mechanism of AA amyloidosis.

AA amyloidosis: pathogenesis and targeted therapy

The understanding of why and how proteins misfold and aggregate into amyloid fibrils has increased considerably during recent years. Central to amyloid formation is an increase in the frequency of the β-sheet structure, leading to hydrogen bonding between misfolded monomers and creating a fibril that is comparably resistant to degradation. Generation of amyloid fibrils is nucleation dependent, and once formed, fibrils recruit and catalyze the conversion of native molecules. In AA amyloidosis, the expression of cytokines, particularly interleukin 6, leads to overproduction of serum amyloid A (SAA) by the liver. A chronically high plasma concentration of SAA results in the aggregation of amyloid into cross-β-sheet fibrillar deposits by mechanisms not fully understood. Therefore, AA amyloidosis can be thought of as a consequence of long-standing inflammatory disease. This review summarizes current knowledge about AA amyloidosis. The systemic amyloidoses have been regarded as intractable conditions, but improvements in the understanding of fibril composition and pathogenesis over the past decade have led to the development of a number of different therapeutic approaches with promising results.

Turkish experience in rheumatoid arthritis patients with clinical apparent amyloid deposition

OBJECTIVES

We evaluated the frequency of clinical apparent amyloid deposition, clinical features and outcome in our rheumatoid arthritis (RA) patients.

METHODS

Medical records of 1415 RA patients were examined. During routine follow-up, RA patients with proteinuria on urinalysis, underwent rectal biopsy.

RESULTS

Eleven patients (0.78%) were diagnosed with clinical apparent amyloid deposition. While the mean annual incidence of AA amyloidosis between 2001 and 2005 was 0.2%, it was 0.13% between 2006 and 2011. At initial presentation, three RA-related AA amyloidosis patients had nephrotic-range proteinuria and renal insufficiency, four had only nephrotic-range proteinuria, three had non-nephrotic-range proteinuria, and one had non-nephrotic-range proteinuria and renal insufficiency. The mean age in RA patients with AA amyloidosis was 60.8 years and disease duration was 12 years. Ten of 11 cases had positive rheumatoid factor. Two RA patients with AA amyloidosis who had been diagnosed in the pre-anti-TNF era died. Of the rest nine patients with AA amyloidosis, eight were administered anti-TNF therapy and one was given rituximab. In four patients, anti-TNF therapy led to disappearance of clinical features, decrement in proteinuria and resulted in improvement of or at least stabilization of renal functions. One patient using anti-TNF therapy died because of tuberculosis. One patient discontinued anti-TNF therapy and developed end-stage renal disease. Two patients have been started to be given anti-TNF therapy recently. In one patient who was given rituximab, there was regression of proteinuria and improvement in renal functions.

CONCLUSIONS

We diagnosed a 0.78% frequency of AA amyloidosis in RA. It seems that - other than the risks of infection, tuberculosis - anti-TNF drugs seem to be effective on RA disease activity and also have renoprotective effects in RA patients with AA amyloidosis.

Transmission of systemic AA amyloidosis in animals

Amyloidoses are a group of protein-misfolding disorders that are characterized by the deposition of amyloid fibrils in organs and/or tissues. In reactive amyloid A (AA) amyloidosis, serum AA (SAA) protein forms deposits in mice, domestic and wild animals, and humans that experience chronic inflammation. AA amyloid fibrils are abnormal β-sheet-rich forms of the serum precursor SAA, with conformational changes that promote fibril formation. Extracellular deposition of amyloid fibrils causes disease in affected animals. Recent findings suggest that AA amyloidosis could be transmissible. Similar to the pathogenesis of transmissible prion diseases, amyloid fibrils induce a seeding-nucleation process that may lead to development of AA amyloidosis. We review studies of possible transmission in bovine, avian, mouse, and cheetah AA amyloidosis.

Clinical characteristics of the patients with systemic amyloidosis in 2000-2010

BACKGROUND

The epidemiology of systemic amyloidosis has been changing in the last decades. We aim to describe the clinical characteristics of the patients seen at our institution with systemic amyloidosis in 2000-2010 and compare them with previous Spanish series.

PATIENTS AND METHODS

An observational, retrospective study was performed on all patients admitted to a tertiary hospital in Madrid, Spain who had been diagnosed of amyloidosis from January 2000 to December 2010. Patients without a proven diagnosis of amyloidosis, with dialysis-associated, senile, or localized forms of amyloidosis were excluded from the study. A systematic review was made of the clinical records, collecting the demographic, clinical and biochemical variables at diagnosis and patients' outcome.

RESULTS

A total of 55 patients were studied, 24 (44%) of whom had AL amyloidosis, 30 (56%) AA amyloidosis, and 1 a familiar form. The most frequent underlying disorders were rheumatoid arthritis (9 patients, 30%) and ankylosing spondylitis (4 cases, 13%). The kidneys were the most frequently involved organ (36 patients, 67%) with nephrotic-range proteinuria at diagnosis (3.4 ± 3.7 g/24 h). Median time to diagnosis was 3 months (interquartile range [IQR]: 1-17). Median follow-up time was 24 months (IQR: 10-91). During follow-up 31 patients died; 18 of those deaths were related to amyloidosis.

CONCLUSIONS

Renal dysfunction dominates the course of systemic amyloidosis, which does not seem to have changed in the last decades. We have observed an important delay in the diagnosis of these processes. Therefore, it is necessary to maintain a high degree of clinical suspicion regarding these conditions.

A marked decline in the incidence of renal replacement therapy for amyloidosis associated with inflammatory rheumatic diseases - data from nationwide registries in Finland

Risk for amyloidosis in rheumatic diseases is associated with a long-lasting inflammation. To assess possible changes in the incidence of terminal uraemia due to amyloidosis associated with rheumatic diseases on a nationwide basis, we scrutinised the files of the Finnish Registry for Kidney Diseases for patients suffering from amyloidosis associated with rheumatoid arthritis (RA), ankylosing spondylitis (AS) or juvenile idiopathic arthritis (JIA) over the period 1995-2008. The registry has an estimated 97-99% coverage of all patients accepted for renal replacement therapy (RRT) in the country. Data on the consumption of antirheumatic drugs were collected from two sources: the Social Insurance Institution's Drug Reimbursement Register, and the Sales Register of the National Agency for Medicines from the above period. Altogether 264 cases were identified. Two hundred twenty-nine of them had RA, 15 AS and 20 JIA. When the total annual number of new admissions to RRT varied between 20 and 37 at the end of 1990s, it was under half of that from 2002 onwards. Over this period, the number of users of low-dose methotrexate (MTX) has increased 3.6-fold, the drug being the most frequently used disease modifying anti-rheumatic drug in Finland. The present nationwide series is the first to show that the incidence of end-stage renal disease due to amyloidosis associated with rheumatic diseases is decreasing. An obvious reason for this is intensive anti-rheumatic drug therapy.

More evidence of declining incidence of amyloidosis associated with inflammatory rheumatic diseases

OBJECTIVE

To assess the incidence, prevalence, and outcome of amyloidosis associated with inflammatory rheumatic diseases.

METHODS

An observational study was performed in the outpatient department of Kainuu Central Hospital from 1993 to 2007. The following criteria were used for the performance of abdominal subcutaneous fat aspiration (ASFA) and/or rectal biopsies: erythrocyte sedimentation rate (ESR) > 40 mm/h at two consecutive visits; and proteinuria (> 0.5 g/day) or serum creatinine > 150 μmol/L. Renal biopsy was performed when there was a high suspicion of amyloidosis in cases with negative findings in the above-mentioned biopsies. In addition, amyloid staining was used routinely for mucosal specimens taken in gastroscopy and colonoscopy. The patients were followed until death or to the end of 2007.

RESULTS

New diagnoses of amyloidosis in the consecutive 5-year periods from 1993 onwards numbered 11, 3, and 5, respectively. During the study period, there was a mean annual incidence of amyloidosis of 1.8 [95% confidence interval (CI) 1.1-2.8)/100,000]. At the end of 2007 there were eight subjects with amyloidosis, giving a point prevalence of 12.0/100,000 (95% CI 5.2-23.6). Five patients out of the 19 underwent haemodialysis because of terminal uraemia and three of them also had renal transplantation. Overall, 12 (63%) patients died after a median survival time of 6 (95% CI 4-8) years, one-third from amyloidosis. The 5-year survival rate of the series was 67% (95% CI 41-86).

CONCLUSION

Amyloidosis is rarely encountered today. ASFA or rectal biopsy facilitates its early diagnosis.

Systemic amyloidosis: a challenge for the rheumatologist

Amyloidosis comprises a group of diseases characterized by the extracellular deposition of insoluble fibrillar proteins. This mechanism generates different clinical syndromes depending on the site and extent of organ involvement. Amyloidosis is classified into categories of systemic and localized disease. Systemic amyloidosis is further subdivided into a hereditary familial form (for example, ATTR amyloidosis), a reactive form (AA amyloidosis), dialysis-related (Abeta(2)M) amyloidosis and immunoglobulin light chain (AL) amyloidosis. Treatment can be symptomatic, directed at the affected organ, or can be directed at reducing the production of the abnormal proteins with different strategies. Despite advances in treatment, the prognosis is still poor and depends on the underlying disease as well as the type and degree of dysfunction in involved organs. Early diagnosis is essential because patients with advanced disease are generally unable to undergo intensive therapy. Patients with systemic amyloidosis often present to a rheumatologist not only because the disease can include musculoskeletal and articular symptoms but also because it can be associated with chronic rheumatic diseases. This Review discusses the clinical features of amyloidosis and its rheumatic manifestations. The various types of amyloidosis, as well their prognosis and treatment, are also presented.

Slaughtered aged cattle might be one dietary source exhibiting amyloid enhancing factor activity

It has been shown that experimental murine AA amyloidosis can be enhanced by dietary ingestion of amyloid fibrils, and it is known that systemic AA amyloidosis occasionally develops in aged cattle. In this study, we examined amyloid deposits in renal and muscular tissues simultaneously obtained from slaughtered aged cattle; from both tissues when affected, amyloid-enhancing activity was also investigated. On histopathology, renal amyloid deposition was seen in nine of the 293 cattle with no history of disease, and minute amyloid deposition in muscular tissue was detectable in one of these nine. All these amyloid deposits were immunohistochemically demonstrated to be AA. Extracts, which might contain amyloid fibril fractions, were isolated from renal and muscular tissues in five of these nine cattle. On SDS-PAGE and Western blot analysis, protein bands immunoreactive to anti-AA serum were detected in the kidney fractions obtained from four of the five latter cattle, but no bands were seen in the muscle fractions of any of the five cattle. Amyloid fibril fractions from two cattle were intravenously injected into group of seven experimentally designed mice for induction of AA amyloidosis. All seven mice injected with kidney fraction developed severe AA amyloidosis, whereas only one of the seven mice given muscle fraction showed slight amyloid deposition in the spleen. These data suggest that food products made from aged cattle possess amyloid-enhancing potential.

Amyloidosis-recent developments

OBJECTIVES

To describe the clinical presentation, diagnosis, classification, grading, evaluation of prognosis, and treatment of amyloidosis against the background of its pathomechanisms.

METHODS

PubMed and MEDLINE databases (1990 to October 2007) and internet were searched for the key word amyloidosis and evaluated on the basis of the authors' own clinical experience and work on the topic.

RESULTS

A clinical suspicion of amyloidosis arises when a patient with a chronic inflammatory disease, plasma cell dyscrasia, or a family history of hereditary amyloidosis develops "an amyloid syndrome" or more rare but specific signs. Microscopy of Congo red stained tissue specimens under polarized light shows birefringent amyloid, which is typed by identification of the amyloid precursor by immunohistochemistry, amino acid sequencing, or proteomics. The diagnosis can be supported by genetic tests. Amyloidosis now covers biochemically and clinically 27 distinct types in man and 9 in animals. Grading to mild, moderate, and severe disease based on laboratory tests and radiology is introduced. Prognosis is affected by the rate of synthesis and the concentration of the circulating precursor. Accurate diagnosis of the underlying disease is mandatory as the treatment is based on disease control and inhibition of amyloid precursor production. Organ-specific treatment, such as transplantation, hemodialysis, treatment of heart failure, pacemakers, and substitution to prevent nutritional deficiencies, is often needed.

CONCLUSIONS

As our knowledge of the pathogenesis of amyloidosis and the structure-function relationship of amyloid proteins increases, new therapies will be developed to prevent protein misfolding and aggregation, inhibit fibrillogenesis, and enhance clearance of amyloid.

Treatment strategies for amyloid A amyloidosis

BACKGROUND

Amyloid A (AA) amyloidosis is a serious complication of a wide range of chronic inflammatory, infectious and neoplastic diseases. A longstanding overproduction of the liver-synthesised cytokine-induced acute phase serum amyloid A (SAA) protein is a key event in the pathogenetic cascade leading to the deposition of AA amyloid in tissues and organs.

OBJECTIVE

The aim of the study was to critically review treatment strategies in AA amyloidosis.

METHODS

A systematic literature review was conducted based on PubMed (January 1980 - April 2008) and selected conference abstracts.

RESULTS/CONCLUSIONS

The current strategy for the treatment of AA amyloidosis is firmly based on the knowledge of the underlying pathogenetic mechanism and aims at reducing the amyloid precursor (SAA) load by intensive anti-inflammatory/immunosuppressive therapy and, in selected instances, anticytokine (TNF-alpha, IL-1beta or IL-6 blockade) therapy, or, when applicable, the eradication of an existing infectious focus (surgery, antimicrobial drugs). Emerging strategies focus on the dissolution of the amyloid deposits using small molecules that either interact with the glycosaminoglycans or the fibril component of the deposits, or deplete amyloid P component.

Clinical strategies for amyloid A amyloidosis secondary to rheumatoid arthritis

Secondary amyloid A (AA) amyloidosis is an important complication of rheumatoid arthritis (RA) and has remarkable variation in frequency worldwide. It is a serious, potentially life-threatening disorder caused by deposition in organs of AA fibrils, which are derived from the circulatory, acute-phase-reactant, serum amyloid A protein (SAA). The SAA1.3 allele can serve not only as a risk factor for the association of AA amyloidosis but also as a poor prognostic factor in Japanese RA patients. Both the association of AA amyloidosis arising early in RA disease course and symptomatic variety and severity were found in amyloidotic patients carrying the SAA1.3 allele. Etanercept for patients with AA amyloidosis who carry the SAA1.3 allele showed the amelioration of rheumatoid inflammation, including marked reduction of SAA and improvement of renal function. In light of the SAA1.3 allele significance in Japanese RA patients, both a tight control by disease-modifying antirheumatic drugs and an early intervention of biologics for RA inflammation should be applied to suppress acute-phase response, thus preventing the association of AA amyloidosis. It is suggested that SAA plays not only an important role in the development of AA amyloidosis but also interacts with events closely involved in metabolic syndrome as a high- and low-grade inflammatory modulator, respectively.

[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.

Amyloidogenic potential of foie gras

The human cerebral and systemic amyloidoses and prion-associated spongiform encephalopathies are acquired or inherited protein folding disorders in which normally soluble proteins or peptides are converted into fibrillar aggregates. This is a nucleation-dependent process that can be initiated or accelerated by fibril seeds formed from homologous or heterologous amyloidogenic precursors that serve as an amyloid enhancing factor (AEF) and has pathogenic significance in that disease may be transmitted by oral ingestion or parenteral administration of these conformationally altered components. Except for infected brain tissue, specific dietary sources of AEF have not been identified. Here we report that commercially available duck- or goose-derived foie gras contains birefringent congophilic fibrillar material composed of serum amyloid A-related protein that acted as a potent AEF in a transgenic murine model of secondary (amyloid A protein) amyloidosis. When such mice were injected with or fed amyloid extracted from foie gras, the animals developed extensive systemic pathological deposits. These experimental data provide evidence that an amyloid-containing food product hastened the development of amyloid protein A amyloidosis in a susceptible population. On this basis, we posit that this and perhaps other forms of amyloidosis may be transmissible, akin to the infectious nature of prion-related illnesses.

[The heart in rheumatic diseases]

As systemic immunological disorders inflammatory rheumatic diseases potentially involve organs and structures beyond the musculo-skeletal system including skin and blood vessels. Various neurological, renal, pulmonary, hematological and cardiac manifestations contribute to the broad clinical picture of connective tissue diseases and vasculitides. Regarding cardiac disease all structures of the heart may be affected. Pericarditis in lupus, mitral valve changes in the antiphospholipid syndrome, myocarditis and coronary artery stenosis in the systemic vasculitides are typical examples in systemic rheumatic diseases. Beyond this, pulmonary hypertension in systemic sclerosis or congenital heart block in newborns of lupus patients are further cardiac issues. Since better treatment options led to more long-lasting courses in connective tissue diseases, cardiovascular complications as a consequence of chronic disease- and therapy-related damage gain increasing attention.

Systemic AA-amyloidosis related to MPO-ANCA microscopic polyangiitis: a case report

We report autopsy findings in an 83-year-old woman with myeloperoxidase-type anti-neutrophil cytoplasmic antibody (MPO-ANCA)-positive microscopic polyangiitis and systemic AA amyloidosis. With a diagnosis of MPO-ANCA-related microscopic polyangiitis, the patient was treated with corticosteroids, but she died of intractable enteritis. Autopsy showed inactive vasculitis affecting small arteries in kidney, lung, intestinal tract, and skeletal muscle. Gastrointestinal viscera were thickened, and AA-amyloid was demonstrated in arterioles and surrounding tissues. Amyloidosis also involved heart, kidney, gallbladder, pancreas, salivary gland, and subcutis. ANCA-positive microscopic polyangiitis appears to have been the likely cause of this patient's AA-amyloidosis.

Oral dimethyl sulfoxide for systemic amyloid A amyloidosis complication in chronic inflammatory disease: a retrospective patient chart review

BACKGROUND

Amyloid A amyloidosis is an obstinate disease complication in chronic inflammatory disease, and there are few effective therapies. The objective of this study was to investigate the effect of oral dimethyl sulfoxide (DMSO) on amyloid A amyloidosis.

METHODS

Fifteen secondary amyloid A amyloidosis patients (4 men, 11 women; age, 23-70 years) were treated with DMSO between 1995 and 2003. DMSO was administered orally in all patients at a dose of 3-20 g/day. The clinical symptoms together with the renal and gastrointestinal functions were evaluated before and after treatment.

RESULTS

Among the 15 patients, amyloid A amyloidosis was a complication of rheumatoid arthritis (RA) in 10, of Crohn's disease in 4, and of Adult Still's disease in 1. Nine cases mainly involved the kidney, with renal dysfunction and proteinuria, five mainly involved the gastrointestinal tract, with protein-losing gastroenteropathy and intractable diarrhea, and one involved both gastrointestinal and renal amyloidosis. DMSO treatment was successful in 10 (66.7%) of the 15 patients (RA, 6/10; Crohn's disease, 4/4; Adult Still's disease, 0/1). Eight weeks of DMSO administration improved the renal function and proteinuria in five out of ten renal amyloidosis patients, but had no effect on those patients with severe and/or advanced renal dysfunction. With regard to gastrointestinal amyloidosis, gastrointestinal symptoms, including diarrhea and protein-losing gastroenteropathy, were improved in six patients. No serious side effects were encountered with the DMSO treatment.

CONCLUSIONS

Oral administration of DMSO is an effective treatment for amyloid A amyloidosis, especially for gastrointestinal involvement and the early stage of renal dysfunction.

Amylose rénale AA secondaire à des bronchectasies

INTRODUCTION

We describe 2 patients with AA renal amyloidosis secondary to bronchiectasis (one patient had tracheobronchomegaly or Mounier-Kuhn syndrome).

CASE REPORTS

The time period between the diagnosis of bronchiectasis and the development of renal amyloidosis was 40 years and 30 years respectively. Both patients evolved to end-stage renal failure requiring dialysis.

CONCLUSION

Although the incidence of renal amyloidosis secondary to bronchectasis has declined, it remains a dreadful complication.

Therapy for immunoglobulin light chain amyloidosis: the new and the old

An accurate diagnosis of amyloidosis and its subtype classification are essential for disease prognostication and treatment. In primary amyloidosis, overall median survival is approximately 2 years and may be less in patients with cardiomyopathy. Current therapy for primary amyloidosis is suboptimal. Controlled studies suggest that treatment with melphalan and prednisone may provide marginal survival benefit. A more aggressive approach such as autologous hematopoietic stem cell transplantation may offer potential for long-term benefit. Although patients undergoing autologous hematopoietic stem cell transplantation are highly selected, response rates can approach 60%, and patients with amyloidosis who respond to treatment have potential for long-term survival. New treatment modalities that were shown to have antitumor activity in multiple myeloma (high-dose dexamethasone and thalidomide) may also be of therapeutic value in primary amyloidosis. Systemic chemotherapy would not be expected to have any beneficial effect on other forms of amyloid and carries significant risk.

The systemic amyloidoses

PURPOSE OF REVIEW

Clinical management of the amyloidoses has historically been the province of rheumatologists, because of the relation to long-standing inflammation in rheumatoid arthritis, ankylosing spondylitis, and juvenile chronic arthritis. Currently, nephrologists, hematologist-oncologists, neurologists, and transplant surgeons all have a diagnostic or therapeutic interest. Current advances, using the tools of physical biochemistry, cell biology, and genetics, have begun to impact the diagnosis and clinical management of these disorders and raise questions regarding our notions of protein conformation in vivo and how nonnatively folded proteins may produce disease.

RECENT FINDINGS

It appears that all amyloidogenic precursors undergo some degree of misfolding that allows them to populate an immediate precursor pool from which they rapidly aggregate. Depending on the particular protein, a variety of mechanisms appear operative, some of which involve nonphysiologic proteolysis, defective physiologic proteolysis, mutations involving changes in thermodynamic or kinetic properties, and pathways that are yet to be defined. Whatever the particular process, the result is a tendency toward oligomeric aggregation followed by the assembly of higher order structures that become insoluble under physiologic conditions. Detailed analyses have been described for transthyretin (senile systemic amyloidosis and familial amyloid polyneuropathy), immunoglobulin light chains (light-chain amyloid), beta2 microglobulin (dialysis-related amyloid), and apolipoprotein A1, and are in process for others. SUMMARY Therapies have been proposed based on precursor stabilization (transthyretin), elimination of the synthesizing cell (light-chain amyloid), fibril disruption and immunization to induce host-mediated aggregate clearance (Alzheimer disease, light-chain amyloid, prions), and aggressive therapy of a primary inflammatory process (amyloid A). During the next decade, the value of these therapies, and others, suggested by studies on the basic properties of cells and proteins, will become clear.

Musculoskeletal disorders in secondary amyloidosis and hereditary fevers

Amyloidosis remains a severe potential complication of many chronic inflammatory disorders, foremost of rheumatoid arthritis. It is not exactly known why some patients develop a progressive amyloidosis while others do not, although latent deposits may be present. It is likely that more potent anti-inflammatory drugs recently used in rheumatoid arthritis have led to a decrease of amyloid-associated (AA) amyloidosis. However, overt amyloidosis remains a severe complication of some chronic inflammatory disorders and it has a poor prognosis. Hereditary fevers are a group of diseases characterized by intermittent bouts of clinical inflammation with focal organ involvement, mainly abdomen, musculoskeletal system and skin. The most frequent is familial Mediterranean fever which affects patients of Mediterranean descent all over the world. Three other types have been recently characterized clinically as well as genetically. A thorough diagnosis is warranted, as clinical and therapeutic management is specific for each of these diseases.

Gastrointestinal Amyloidosis: Approach to Treatment

The main treatment goals in amyloidosis are twofold: 1) to diagnose the underlying disease state accurately to guide effective primary therapy (if available) and 2) to ameliorate symptoms. The correct diagnosis is essential because disease-modifying therapies vary widely according to the underlying primary pathology. Primary treatment options remain limited. The best evidence is for high-dose chemotherapy, followed by autologous stem cell transplantation in patients with primary systemic amyloidosis. High-flux hemodialysis (HD) may prevent HD-related amyloidosis. Liver transplantation may be an option for patients with familial amyloidotic polyneuropathy. Several novel specific therapies are under investigation, including small molecule drugs and vaccines. Their efficacy and safety in humans remain to be demonstrated. In the absence of specific cures, symptom-directed therapy assumes a paramount role and can improve quality of life by mitigating diarrhea or pain, for example.

Renal type AA amyloidosis associated with rheumatoid arthritis: a cohort study showing improved survival on treatment with pulse cyclophosphamide

OBJECTIVE

To determine the incidence of renal AA amyloidosis and its association with rheumatoid arthritis (RA) in a cohort of all renal biopsies at one referral hospital and to measure the effect of a monthly pulse of cyclophosphamide on renal function and survival in these RA patients.

METHOD

All renal biopsies with proven AA amyloidosis from a single pathology unit linked to a major nephrology referral unit in a university hospital were selected retrospectively and RA patients were identified. We studied 6931 renal biopsies. The effect of treatment with and without pulse cyclophosphamide on renal function and survival was studied in these patients.

RESULTS

From March 1977 to February 1999, the incidence of AA amyloidosis was 2.4 cases/yr. The incidence and prevalence of the association of AA amyloidosis with RA were 0.68 cases/yr and 0.22% (15/6931) respectively. RA patients treated with cyclophosphamide (n=6) had a lower rate of renal function loss (P=0.013) and a higher median survival (P=0.026) than untreated patients (n=9). During the follow-up period, two out of six treated patients (33%) and all nine untreated patients (100%) died.

CONCLUSIONS

AA amyloidosis is a rare complication of RA and complicates the evaluation of treatment. This retrospective study suggests that treatment with cyclophosphamide is able to reduce the incidence of end-stage renal failure and to increase survival. Prospective studies are needed to clarify this issue.