Significance of SAA1.3 allele genotype in Japanese patients with amyloidosis secondary to rheumatoid arthritis

AA amyloidosis in vertebrates: epidemiology, pathology and molecular aspects

AA amyloidosis is a prototypic example of systemic amyloidosis: it results from the prolonged overproduction of SAA protein produced in response to chronic inflammation. AA amyloidosis primarily affects the kidneys, liver, spleen, gastrointestinal tract, leading to a variety of symptoms. First, this review examines AA amyloidosis in humans, focusing on pathogenesis, clinical presentation, and diagnosis and then in animals. In fact AA amyloidosis is the only systemic amyloidosis that has been largely documented in a remarkable number of vertebrate species: mammals, birds, and fishes, especially in individuals with comorbidities, chronic stress, or held in captivity. Secondly, here, we summarise independent sets of evidence obtained on different animal species, exploring the possible transmissibility of AA amyloidosis especially in crowded or confined populations. Finally, biochemical and structural data on native SAA and on AA amyloid fibrils from human, murine, and cat ex vivo samples are discussed. The available structural data depict a complex scenario, where SAA can misfold forming highly different amyloid assemblies. This review highlights the complexity of AA amyloidosis, emphasising the need for further research into its spread in the animal kingdom, its structural aspects, and pathogenetic mechanisms to evaluate its impact on human and animal health.

Predicting genetic risk factors for AA amyloidosis in Algerian patients with familial Mediterranean fever

Renal amyloid-associated (AA) amyloidosis is a harmful complication of familial Mediterranean fever (FMF). Its occurrence involves polymorphisms and mutations in the Serum Amyloid A1 (SAA1) and Mediterranean Fever (MEFV) genes, respectively. In Algeria, the association between SAA1 variants and FMF-related amyloidosis was not investigated, hence the aim of this case-control study. It included 60 healthy controls and 60 unrelated FMF patients (39 with amyloidosis, and 21 without amyloidosis). All were genotyped for the SAA1 alleles (SAA1.1, SAA1.5, and SAA1.3), and a subset of them for the - 13 C/T polymorphism by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Comparisons between genotype and allele frequencies were performed using Chi-square and Fisher tests. The SAA1.1/1.1 genotype was predominant in amyloid FMF patients, compared to non-amyloid FMF patients (p = 0.001) and controls (p < 0.0001). SAA1.1/1.5 was higher in non-amyloid patients (p = 0.0069) and in controls (p = 0.0082) than in patients with amyloidosis. Bivariate logistic regression revealed an increased risk of AA amyloidosis with three genotypes, SAA1.1/1.1 [odds ratio 7.589 (OR); 95% confidence interval (CI): 2.130-27.041] (p = 0.0018), SAA1.1/1.3 [OR 5.700; 95% CI: 1.435-22.644] (p = 0.0134), and M694I/M694I [OR 4.6; 95% CI: 1.400-15.117] (p = 0.0119). The SAA1.1/1.5 genotype [OR 0.152; 95% CI: 0.040-0.587] (p = 0.0062) was protective against amyloidosis. In all groups, the - 13 C/C genotype predominated, and was not related to renal complication [OR 0.88; 95% CI: 0.07-10.43] (p = 0.915). In conclusion, in contrast to the - 13 C/T polymorphism, the SAA1.1/1.1, SAA1.1/1.3 and M694I/M694I genotypes may increase the risk of developing renal AA amyloidosis in the Algerian population.

Down-regulated Th17 cells in a patient with familial Mediterranean fever associated with amyloid A amyloidosis in the treatment of canakinumab

Autoinflammatory diseases are innate immune-mediated inflammatory disorders, unlike autoimmune diseases, which are characterised by abnormalities in adoptive immunity, although autoimmune and autoinflammatory diseases have certain similar clinical features. Familial Mediterranean fever (FMF), the most common monogenic autoinflammatory disease, is associated with mutations in the MEFV gene that encodes pyrin, which results in inflammasome activation and uncontrolled production of interleukin (IL)-1β. Regular use of colchicine, the primary drug for FMF treatment, prevents febrile attacks and reduces the long-term risk of subsequent complications of amyloid A (AA) amyloidosis. However, a minority of FMF patients develop colchicine resistance, and anti-IL-1β treatment with canakinumab, which is a genetically modified human IgG subclass type 1 (IgG1) monoclonal antibody specific for human IL-1β, was beneficial in inhibiting inflammation in such patients. Here, we present a patient with FMF associated with AA amyloidosis, who was treated with canakinumab and demonstrated down-regulated Th17 cells and activated Th17 cells (from 21.4% to 12.8%, and from 1.45% to 0.83%, respectively) in peripheral blood, as shown by immunophenotyping via multicolour flow cytometry and by disease activity and improved laboratory inflammatory surrogate markers-C-reactive protein (CRP) and serum AA protein (SAA). CRP had values within normal limits, but SAA did not (Spearman's rank correlation coefficient; ρ = 0.133). We report that SAA and IL-1β may differentiate Th17 cells from CD4+-naïve T cells, and we discuss interactions between autoinflammation and autoimmunity as a model based on this case, through modes of action with IL-1β and SAA. This report is the first demonstrating that an IL-1β antagonist may reduce Th17 cells in FMF as a therapeutic option.

Case report: Rapid development of amyloid A amyloidosis in temporal arteritis with SAA1.3 allele; An unusual case of intestinal amyloidosis secondary to temporal arteritis

Temporal arteritis (TA) is a large-vessel vasculitis mostly seen in older patients. Amyloid A (AA) amyloidosis secondary to a chronic inflammation induces multiple organ dysfunctions, including a dysfunction of the gastrointestinal tract. Herein, we present a case of TA complicated by AA amyloidosis that was resistant to oral and intravenous steroids. An 80-year-old man with a history of new-onset headache, jaw claudication, and distended temporal arteries was referred to our department. On admission, the patient presented with tenderness and a subcutaneous temporal nodule in both temple arteries. Ultrasonography of the nodule revealed an anechoic perivascular halo surrounding the right temporal artery. Following the diagnosis of TA, high-dose prednisolone therapy was initiated. However, the patient presented with recurrent abdominal pain and refractory diarrhea. Due to the unclear origin of refractory diarrhea, an extensive workup, including biopsy of the duodenal mucosa, was performed. Endoscopy revealed chronic inflammation in the duodenum. Immunohistochemical analysis of duodenal mucosal biopsy samples revealed AA amyloid deposition resulting in the diagnosis of AA amyloidosis. After tocilizumab (TCZ) administration, refractory diarrhea reduced; however, the patient died of intestinal perforation 1 month after the start of TCZ administration. Gastrointestinal involvement was the main clinical manifestation of AA amyloidosis in the present case. This case highlights the importance of bowel biopsy screening for amyloid deposition in patients with unexplained gastrointestinal tract symptoms, even in a recent onset of large-vessel vasculitis. In the present case, the carriage of the SAA1.3 allele likely contributed to the rare association of AA amyloidosis with TA.

Post-translational modification of amyloid a protein in patients with AA amyloidosis

AA amyloidosis is a disease caused by extracellular deposition of insoluble β-pleated sheet fibrils composed of amyloid A (AA) protein, an amino (N)-terminal fragment of serum amyloid A (SAA). The deposits disrupt tissue structure and compromise organ function. Although the disease is systemic, deposition in kidney glomeruli is the most common manifestation. The leading cause of AA amyloidosis is sustained or recurrent inflammation accompanied by elevated levels of SAA. Factors determining the conversion of SAA to AA amyloid fibrils have yet to be fully resolved. Herein, we present liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis of AA proteins purified from eight patients with AA amyloidosis. For the first time, post-translational modifications (PTM), including carbamylation, acetylation and oxidation, were identified on AA peptides; all eight samples showed some degree of PTM. The amyloid in 6 samples comprised peptides derived from SAA1 with few or none from SAA2, while the other two samples contained both SAA1- and SAA2-derived peptides. N-terminal AA peptides beginning with Arg1 as well as AA peptides starting with Ser2 were present in five of the eight samples, while all or nearly all of the N-terminal peptides in the other three samples lacked Arg1. These data demonstrate that multiple species of AA amyloid proteins can comprise the subunits in amyloid fibrils and raise the possibility that PTM may play a role in fibrillogenesis.

Association between serum amyloid A and rheumatoid arthritis: A systematic review and meta-analysis

BACKGROUNDS

Consistent correlation of serum amyloid A (SAA) to rheumatoid arthritis (RA) is not completely established. The present study is to systematically summarize their relationship.

METHODS

Publications up to may 2021 were examined using key terms in the PubMed, Cochrane Library, Embase and China national knowledge infrastructure (CNKI) databases.

RESULTS

The total 33 studies, involving in 3524 RA cases and 3537 normal participants, were included. The pooled result indicated that the SAA level in the RA group was markedly higher than that in the control group [standardized mean difference (SMD) = 0.80, 95% CI (0.51, 1.08)]. By stratified analyses, the concentration of SAA was found to be gradually increased with the aggravation of RA. Additionally, the meta-analysis of correlation demonstrated that SAA levels were positively associated with the levels of disease activity score 28 (DAS28) [r = 0.55, 95% CI (0.15, 0.94)], erythrocyte sedimentation rate (ESR) [r = 0.65, 95% CI (0.53, 0.76)], C-reactive protein (CRP) [r = 0.92, 95% CI (0.57, 1.57)], rheumatoid factor (RF) [r = 0.24, 95% CI (0.09, 0.39)], interleukin 4 (IL-4) [r = 0.54, 95% CI (0.30, 0.78)], interleukin 6 (IL-6) [r = 0.46, 95% CI (0.27, 0.65)], interleukin 10 (IL-10) [r = 0.53, 95% CI (0.29, 0.77)], interleukin 17 (IL-17) [r = 0.52, 95% CI (0.27, 0.77)], and anti-cyclic citrullinated peptide antibody (A-CCP) [r = 0.32, 95% CI (0.15, 0.50)], but inversely linked with the levels of hemoglobin [r=-0.51, 95% CI (-0.84, -0.18)]. Furthermore, the allele of SAA 1.3 was actively related with increased risks of RA [OR=1.30, 95% CI (1.02, 1.65)] and of RA with amyloidosis [OR=2.06, 95% CI (1.63, 2.60)]. Besides, the genotype of SAA 1.3/1.3 was positively connected with the risks of RA [OR=1.56, 95% CI (1.00, 2.43)] and of RA with amyloidosis [OR=4.47, 95% CI (2.70, 7.41)].

CONCLUSIONS

High levels of SAA might be associated with elevated risk of RA, and the concentration of SAA might be gradually increased with the aggravation of RA. Moreover, high levels of SAA might play a vital role in RA by enhancing the levels of DAS28, ESR, CRP, RF, IL-4, IL-6, IL-10, IL-17 and A-CCP, or by attenuating hemoglobin levels. More importantly, the allele of SAA 1.3 and genotype of SAA 1.3/1.3 might be the risk factor of RA and of RA with amyloidosis.

Biologic therapy for amyloid A amyloidosis secondary to rheumatoid arthritis treated with interleukin 6 therapy: Case report and review of literature

INTRODUCTION

Secondary amyloidosis is a rare complication of rheumatoid arthritis (RA) that is histologically characterized by the deposition of amyloid fibrils in target organs, such as the kidneys and gastrointestinal tract. Controlling the inflammatory response is essential to prevent organ dysfunction in amyloid A (AA) amyloidosis secondary to RA, and no clear treatment strategy exists.

PATIENT CONCERNS AND DIAGNOSIS

A 66-year-old woman with RA, who had been treated with disease-modifying anti-rheumatic drugs for 1 year, presented with recurrent abdominal pain and prolonged diarrhea. Endoscopy showed chronic inflammation, and colon tissue histology confirmed AA amyloidosis.

INTERVENTIONS AND OUTCOMES

After tocilizumab therapy was begun, her diarrhea and abdominal pain subsided, and articular symptoms improved. Biologic drugs for RA have been used in patients with secondary AA amyloidosis, including tumor necrosis factor and Janus kinase inhibitors, interleukin 6 blockers, and a T cell modulator. Here, we systematically review existing case reports and compare the outcomes of RA-related AA amyloidosis after treatment with various drugs.

CONCLUSION

The data indicate that biologic drugs like tocilizumab might be treatments of choice for AA amyloidosis secondary to RA.

Gastric perforation caused by secondary systemic amyloidosis

Amyloid A amyloidosis secondary to chronic inflammation involves systemic organs and tissues, including the gastrointestinal tract. In the present case, massive amyloid deposit caused gastric perforation. IgM co-deposition in the glomeruli was another finding of note.

Serum Amyloid A in Inflammatory Rheumatic Diseases: A Compendious Review of a Renowned Biomarker

Serum amyloid A (SAA) is an acute phase protein with a significant importance for patients with inflammatory rheumatic diseases (IRD). The central role of SAA in pathogenesis of IRD has been confirmed by recent discoveries, including its involvement in the activation of the inflammasome cascade and recruitment of interleukin 17 producing T helper cells. Clinical utility of SAA in IRD was originally evaluated nearly half a century ago. From the first findings, it was clear that SAA could be used for evaluating disease severity and monitoring disease activity in patients with rheumatoid arthritis and secondary amyloidosis. However, cost-effective and more easily applicable markers, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), overwhelmed its use in clinical practice. In the light of emerging evidences, SAA has been discerned as a more sensitive biomarker in a wide spectrum of IRD, especially in case of subclinical inflammation. Furthermore, a growing number of studies are confirming the advantages of SAA over many other biomarkers in predicting and monitoring response to biological immunotherapy in IRD patients. Arising scientific discoveries regarding the role of SAA, as well as delineating SAA and its isoforms as the most sensitive biomarkers in various IRD by recently developing proteomic techniques are encouraging the revival of its clinical use. Finally, the most recent findings have shown that SAA is a biomarker of severe Coronavirus disease 2019 (COVID-19). The aim of this review is to discuss the SAA-involving immune system network with emphasis on mechanisms relevant for IRD, as well as usefulness of SAA as a biomarker in various IRD. Therefore, over a hundred original papers were collected through an extensive PubMed and Scopus databases search. These recently arising insights will hopefully lead to a better management of IRD patients and might even inspire the development of new therapeutic strategies with SAA as a target.

Amyloidosis in Heart Failure

PURPOSE

Amyloidosis represents an increasingly recognized but still frequently missed cause of heart failure. In the light of many effective therapies for light chain (AL) amyloidosis and promising new treatment options for transthyretin (ATTR) amyloidosis, awareness among caregivers needs to be raised to screen for amyloidosis as an important and potentially treatable differential diagnosis. This review outlines the diversity of cardiac amyloidosis, its relation to heart failure, the diagnostic algorithm, and therapeutic considerations that should be applied depending on the underlying type of amyloidosis.

RECENT FINDINGS

Non-biopsy diagnosis is feasible in ATTR amyloidosis in the absence of a monoclonal component resulting in higher detection rates of cardiac ATTR amyloidosis. Biomarker-guided staging systems have been updated to facilitate risk stratification according to currently available biomarkers independent of regional differences, but have not yet prospectively been tested. Novel therapies for hereditary and wild-type ATTR amyloidosis are increasingly available. The complex treatment options for AL amyloidosis are improving continuously, resulting in better survival and quality of life. Mortality in advanced cardiac amyloidosis remains high, underlining the importance of early diagnosis and treatment initiation. Cardiac amyloidosis is characterized by etiologic and clinical heterogeneity resulting in a frequently delayed diagnosis and an inappropriately high mortality risk. New treatment options for this hitherto partially untreatable condition have become and will become available, but raise challenges regarding their implementation. Referral to specialized centers providing access to extensive and targeted diagnostic investigations and treatment initiation may help to face these challenges.

Amyloid A amyloidosis in a patient with Caplan's syndrome, with special reference to genetic predisposition

Secondary amyloid A (AA) amyloidosis, which is a disorder of protein conformation and metabolism, is an important serious complication of inflammatory diseases, especially rheumatoid arthritis (RA). AA amyloidosis develops when AA fibrils, which are derived from the acute-phase reactant, serum amyloid AA (SAA) protein, in the circulation, are deposited in organs and cause systemic organ dysfunction. Caplan's syndrome, or rheumatoid pneumoconiosis, is a rare type of lung disease in which individuals suffering from RA develop lung nodules that are associated with occupational exposure to silica and coal dust. Confirmation of diagnosing as Caplan's syndrome requires the patient's occupational history, imaging studies, and serology. A 72-year-old male, working as a tunnel construction worker for 38 years, with RA who had both chronic cardiac and renal dysfunction was referred to our hospital. He received a diagnosis of pneumoconiosis about 20 years ago, after which he was also diagnosed with RA. So far we performed medical English literature searches on the combination of Caplan's syndrome with AA amyloidosis; there were no articles in relation to such association. Although RA is one of the most common underlying diseases that occur with AA amyloidosis, our report here is the first description of a case of Caplan's syndrome associated with AA amyloidosis. In this report, we provide details about this rare disease occurring with AA amyloidosis and discuss on the possible pathogenesis of AA amyloidosis from a genetic point of aetiological view.

Association Between Centromere- and Topoisomerase-specific Immune Responses and the Degree of Microangiopathy in Systemic Sclerosis

OBJECTIVE

Autoreactive antibody responses, including the use of several isotypes of autoantibodies, have been shown to be associated with clinical outcome in several rheumatic autoimmune diseases. The goals of this study were to evaluate whether (1) anticentromere antibody (ACA)- and antitopoisomerase antibody (ATA)-specific isotype expression, and (2) organ involvement are associated with the degree of microangiopathy in systemic sclerosis (SSc).

METHODS

ACA and ATA IgG, IgM, and IgA levels were measured in baseline serum samples of ACA IgG-positive (+) and ATA IgG+ patients with SSc. The degree of microangiopathy was determined based on nailfold videocapillaroscopy (NVC) images collected at the same point in time. Logistic regression analyses with autoantibodies, clinical characteristics, isotype expression, and ACA and ATA IgG, IgM, and IgA levels as independent variables, and NVC pattern as the dependent variable were performed.

RESULTS

In 164 patients, isotype levels and degree of microangiopathy were evaluated. Logistic regression confirmed the association of the degree of microangiopathy with the presence of digital ulcers (OR 3.07, 95% CI 1.43-6.60), interstitial lung disease (OR 3.41, 95% CI 1.11-10.61), and pulmonary arterial hypertension (OR 5.58, 95% CI 2.05-17.81). ATA positivity was associated with more severe microangiopathy (OR 2.09, 95% CI 1.05-4.13). Patients who expressed solely ACA IgG showed a trend towards less severe microangiopathy compared to patients also expressing ACA IgM and/or IgA. Levels of ACA IgG and ATA IgM were found to be associated with microangiopathy severity.

CONCLUSION

We observed an association between ACA and ATA responses and the degree of microangiopathy in SSc. These findings might indicate that the breadth of the autoimmune response, as reflected by autoantibody production and microvascular damage, interacts in the pathophysiology of SSc.

Renal Parenchymal Thickness in Patients with Systemic Sclerosis Is Related to Intrarenal Hemodynamic Variables and Raynaud Renal Phenomenon

Objective.

Renal involvement in systemic sclerosis (SSc) ranges from urinary abnormalities, reduction of glomerular filtration rate, and high renal resistive index, to scleroderma renal crisis. Intrarenal resistance indices are considered markers of renal SSc-associated vasculopathy. The aim of this study is to evaluate renal morphological variables, such as renal length, parenchymal thickness, atrophy index, and renal sinus in patients with SSc and to correlate it with renal function and hemodynamic variables.

Methods.

There were 92 patients with SSc and 40 healthy controls (HC) enrolled in this study. Doppler and renal ultrasound (US) including renal length, parenchymal thickness, atrophy index, renal sinus, and intrarenal resistive index were measured in patients with SSc and HC.

Results.

Renal US showed significant differences between HC and patients with SSc. The renal length (mm; 106.7 ± 5.1 vs 102.3 ± 8.4) and renal sinus (70.7 ± 7.9 vs 65.3 ± 7.7 mm) were significantly (p = 0.001) higher in HC than patients with SSc. The parenchymal thickness was significantly (p = 0.004) higher in HC than patients with SSc (18 ± 3.1 vs 16.3 ± 2.5 mm). Pulsatility index, resistive index, and systolic/diastolic ratio were significantly (p < 0.0001) lower in HC than patients with SSc. The renal length was significantly (p = 0.004) higher in diffuse cutaneous SSc (105 ± 8.4) than in limited cutaneous SSc (99.5 ± 7.5).

Conclusion.

In SSc, kidney involvement is subclinical and is related to vascular injury, Raynaud phenomenon, and chronic hypoxia that can modify renal morphology. Serum creatinine is a poor marker of renal damage, and renal US could be a useful tool — together with Doppler — to evaluate renal involvement in a systemic and chronic disease such as SSc.

Acute phase reactant serum amyloid A in inflammation and other diseases

Acute-phase reactant serum amyloid A (A-SAA) plays an important role in acute and chronic inflammation and is used in clinical laboratories as an indicator of inflammation. Although both A-SAA and C-reactive protein (CRP) are acute-phase proteins, the detection of A-SAA is more conclusive than the detection of CRP in patients with viral infections, severe acute pancreatitis, and rejection reactions to kidney transplants. A-SAA has greater clinical diagnostic value in patients who are immunosuppressed, patients with cystic fibrosis who are treated with corticoids, and preterm infants with late-onset sepsis. Nevertheless, for the assessment of the inflammation status and identification of viral infection in other pathologies, such as bacterial infections, the combinatorial use of A-SAA and other acute-phase proteins (APPs), such as CRP and procalcitonin (PCT), can provide more information and sensitivity than the use of any of these proteins alone, and the information generated is important in guiding antibiotic therapy. In addition, A-SAA-associated diseases and the diagnostic value of A-SAA are discussed. However, the relationship between different A-SAA isotypes and their human diseases are mostly derived from research laboratories with limited clinical samples. Thus, further clinical evaluations are necessary to confirm the clinical significance of each A-SAA isotype. Furthermore, the currently available A-SAA assays are based on polyclonal antibodies, which lack isotype specificity and are associated with many inflammatory diseases. Therefore, these assays are usually used in combination with other biomarkers in the clinic.

Serum amyloid A1 (SAA1) gene polymorphisms in Japanese patients with adult-onset Still's disease

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder in which inflammasome activation plays a pathophysiological role. In view of the inflammatory nature of AOSD, we investigated whether serum amyloid A (SAA) gene polymorphisms affect the susceptibility of patients with AOSD.Eighty-seven Japanese patients with AOSD and 200 healthy Japanese subjects were recruited in this study. The genotypes of the -13C/T SNP in the 5'-flanking region of the SAA1 gene (rs12218) and two SNPs within exon 3 of SAA1 (2995C/T and 3010C/T polymorphisms) were determined using polymerase chain reaction fragment length polymorphism (PCR-RFLP) assay in all subjects. In AOSD patients, exons 1, 2, 3, and 10 of the MEFV gene were also genotyped by direct sequencing.The frequency of the SAA1.3 allele was increased in AOSD patients compared with that in healthy subjects (43.1% versus 37.5%), but the difference was not significant. The -13T allele was more frequently observed in AOSD patients than in healthy subjects (50.6% versus 41.0%, P = .0336). AOSD patients with the -13T allele had been treated with immunosuppressants more frequently than those without this allele. MEFV mutations were detected in 49 patients with AOSD (49/87, 57.3%). AOSD patients with MEFV variants frequently exhibit macrophage activation syndrome, but the difference was not significant (34.7% versus 18.4%, P = .081). Also, there was no significant difference in SAA1 -13C/T allele frequency between AOSD patients with and without MEFV mutations.Our data shows a significant association between T allele of rs12218 and AOSD in Japanese population.

AA amyloidosis - Benefits and prospects of IL-6 inhibitors

AA amyloidosis may develop in patients with active chronic inflammation. Serum amyloid A (SAA), the precursor of the AA protein, is strongly amplified in the liver under the stimulation of inflammation-associated cytokines, such as IL-6, TNF, and IL-1. Sustained inflammation, aging, and polymorphisms in the SAA1.3 genotype are dependent risk factors for the formation of AA amyloidosis. The most rational treatment strategy for AA amyloidosis is to inhibit the production of SAA. Treatments for AA amyloidosis involving biologics have recently been emphasized. TNF inhibitors and abatacept reduce SAA levels; however, complete normalization is not always achieved. IL-6 inhibitors may normalize SAA levels in most patients in whom a sufficient concentration of medication is maintained in the blood. Therefore, treatments with IL-6 inhibitors represent an excellent therapeutic strategy for AA amyloidosis and have been verified by recent studies.

Secondary, AA, Amyloidosis

Secondary, AA, amyloidosis is a rare systemic complication that can develop in any long-term inflammatory disorder, and is characterized by the extracellular deposition of fibrils derived from serum amyloid A (SAA) protein. SAA is an acute-phase reactant synthetized largely by hepatocytes under the transcriptional regulation of proinflammatory cytokines. The kidney is the major involved organ with proteinuria as first clinical manifestation; renal biopsy is the commonest diagnostic investigation. Targeted anti-inflammatory treatment promotes normalization of circulating SAA levels preventing amyloid deposition and renal damage. Novel therapies aimed at promoting clearance of existing amyloid deposits soon may be an effective treatment approach.

[Causes and treatment of systemic amyloidosis]

BACKGROUND

Systemic amyloidoses are rare protein deposition disorders, which are often diagnosed in an advanced stage of the disease due to non-specific symptoms. Any chronic inflammatory disease can lead to an AA-type amyloidosis.

AIM

This paper summarizes the current state of the art of diagnosis and treatment of AA amyloidosis and presents data from the past 10 years of our amyloidosis center.

MATERIAL AND METHODS

Our data represents an analysis of our cohort of patients with amyloidosis and a selective research in the PubMed database for AA amyloidosis.

RESULTS

The underlying diseases comprise autoinflammatory syndromes, polyarthritis, and chronic inflammatory bowel and lung diseases. Renal organ involvement is the most prevalent in AA amyloidosis. It can be detected early through the evaluation of proteinuria. The treatment depends on the individual underlying disease. Patients without an associated inflammatory disease are considered to have idiopathic AA amyloidosis and empiric treatment is mandatory.

DISCUSSION

Survival of this fatal disease has recently improved due to the new diagnostic tools and treatment options; however, early diagnosis plays a crucial role in the prevention of end-stage renal failure. New therapeutic strategies aim to remove existing amyloid deposits.

iTRAQ technology-based identification of human peripheral serum proteins associated with depression

Clinical depression is one of the most common and debilitating psychiatric disorders and contributes to increased risks of disability and suicide. Differentially expressed serum proteins may serve as biomarkers for diagnosing depression. In this study, samples from depressed patients are aggregated into a pool (22×100μL serum was used) and samples from healthy volunteers are aggregated into the other pool (20×100μL serum was used). Isobaric tag for relative and absolute quantitation (iTRAQ) technology and tandem mass spectrometry were employed to screen for differentially expressed serum protein in two separate pools. We identified 472 proteins in the serum samples, and 154 of these presented differences in abundance between the depression and control groups. Ingenuity pathway analysis (IPA) was employed to identify the highest scoring proteins in signaling pathway networks. Finally, four differentially expressed proteins were validated by enzyme-linked immuno sorbent assay (ELISA). Proteomic studies revealed that levels of c-reaction protein (CRP), inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), serum amyloid A1 (SAA1) and angiopoietin-like 3 (ANGPTL3) were substantially increased in depressed patients compared with the healthy control group. Therefore, these differentially expressed proteins may represent potential markers for the clinical diagnosis of depression.

Structural requirements of glycosaminoglycans for facilitating amyloid fibril formation of human serum amyloid A

Serum amyloid A (SAA) is a precursor protein of amyloid fibrils. Given that heparan sulfate (HS), a glycosaminoglycan (GAG), is detected in amyloid deposits, it has been suggested that GAG is a key component of amyloid fibril formation. We previously reported that heparin (an analog of HS) facilitates the fibril formation of SAA, but the structural requirements remain unknown. In the present study, we investigated the structural requirements of GAGs for facilitating the amyloid fibril formation of SAA. Spectroscopic analyses using structurally diverse GAG analogs suggested that the fibril formation of SAA was facilitated irrespective of the backbone structure of GAGs; however, the facilitating effect was strongly correlated with the degree of sulfation. Microscopic analyses revealed that the morphologies of SAA aggregates were modulated by the GAGs. The HS molecule, which is less sulfated than heparin but contains highly sulfated domains, exhibited a relatively high potential to facilitate fibril formation compared to other GAGs. The length dependence of fragmented heparins on the facilitating effect suggested that a high density of sulfate groups is also required. These results indicate that not only the degree of sulfation but also the lengths of sulfated domains in GAG play important roles in fibril formation of SAA.

Serum amyloid A1: Structure, function and gene polymorphism

Inducible expression of serum amyloid A (SAA) is a hallmark of the acute-phase response, which is a conserved reaction of vertebrates to environmental challenges such as tissue injury, infection and surgery. Human SAA1 is encoded by one of the four SAA genes and is the best-characterized SAA protein. Initially known as a major precursor of amyloid A (AA), SAA1 has been found to play an important role in lipid metabolism and contributes to bacterial clearance, the regulation of inflammation and tumor pathogenesis. SAA1 has five polymorphic coding alleles (SAA1.1-SAA1.5) that encode distinct proteins with minor amino acid substitutions. Single nucleotide polymorphism (SNP) has been identified in both the coding and non-coding regions of human SAA1. Despite high levels of sequence homology among these variants, SAA1 polymorphisms have been reported as risk factors of cardiovascular diseases and several types of cancer. A recently solved crystal structure of SAA1.1 reveals a hexameric bundle with each of the SAA1 subunits assuming a 4-helix structure stabilized by the C-terminal tail. Analysis of the native SAA1.1 structure has led to the identification of a competing site for high-density lipoprotein (HDL) and heparin, thus providing the structural basis for a role of heparin and heparan sulfate in the conversion of SAA1 to AA. In this brief review, we compares human SAA1 with other forms of human and mouse SAAs, and discuss how structural and genetic studies of SAA1 have advanced our understanding of the physiological functions of the SAA proteins.

Risk factors for AA amyloidosis in Germany

OBJECTIVE

To identify risk factors for serum amyloid-A (AA) amyloidosis in patients living in Germany.

METHODS

Clinical and genetic data were obtained from 71 patients with AA amyloidosis. SAA1 genotypes were analyzed in 231 individuals. Control groups comprised 45 patients with long-standing inflammatory diseases without AA amyloidosis and 56 age-matched patients without any inflammatory disease.

RESULTS

The most frequent underlying diseases of AA amyloidosis were familial Mediterranean fever (FMF) (n = 24, 34%) and inflammatory rheumatic diseases (n = 30, 42%). Patients without any known underlying disease (n = 11, 16%) were considered as having idiopathic AA amyloidosis. Patients with FMF were significantly younger at disease onset and younger at diagnosis of AA amyloidosis compared with patients with rheumatic diseases. Patients with idiopathic AA amyloidosis were older than patients with definite rheumatic diseases. Patients with FMF and high penetrance MEFV gene mutations had a relative risk of 1.73 for AA amyloidosis. Patients with FMF or a rheumatic disease and the SAA1 α/α genotype had a relative risk of 4.86 and 2.53, respectively, for developing an AA amyloidosis. The prevalence of this risk genotype was 36% in German patients without an inflammatory disease, 92% in German patients with AA amyloidosis and 100% in German patients with idiopathic AA amyloidosis.

CONCLUSIONS

Risk factors for AA amyloidosis are the presence of a hereditary autoinflammatory or chronic rheumatic disease, elevated C-reactive protein and SAA serum levels, a long delay of a sufficient therapy, an advanced age and the SAA1α/α genotype.

The rate and significance of type 1/type 2 serum amyloid A protein gene polymorphisms in patients with ankylosing spondylitis and amyloidosis

A relationship between the presence of amyloidosis and SAA1 genotype has been shown in recent studies of (principally) familial Mediterranean fever patients. We found that the SAA1 rs12218 polymorphism was significantly more prevalent in ankylosing spondylitis patients with amyloidosis.

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.

Systemic AA amyloidosis: epidemiology, diagnosis, and management

The term “amyloidosis” encompasses the heterogeneous group of diseases caused by the extracellular deposition of autologous fibrillar proteins. The global incidence of amyloidosis is estimated at five to nine cases per million patient-years. While amyloid light-chain (AL) amyloidosis is more frequent in developed countries, amyloid A (AA) amyloidosis is more common in some European regions and in developing countries. The spectrum of AA amyloidosis has changed in recent decades owing to: an increase in the median age at diagnosis; a percent increase in the frequency of primary AL amyloidosis with respect to the AA type; and a substantial change in the epidemiology of the underlying diseases. Diagnosis of amyloidosis is based on clinical organ involvement and histological evidence of amyloid deposits. Among the many tinctorial characteristics of amyloid deposits, avidity for Congo red and metachromatic birefringence under unidirectional polarized light remain the gold standard. Once the initial diagnosis has been made, the amyloid subtype must be identified and systemic organ involvement evaluated. In this sense, the ¹²³I-labeled serum amyloid P component scintigraphy is a safe and noninvasive technique that has revolutionized the diagnosis and monitoring of treatment in systemic amyloidosis. It can successfully identify anatomical patterns of amyloid deposition throughout the body and enables not only an initial estimation of prognosis, but also the monitoring of the course of the disease and the response to treatment. Given the etiologic diversity of AA amyloidosis, common therapeutic strategies are scarce. All treatment options should be based upon a greater control of the underlying disease, adequate organ support, and treatment of symptoms. Nevertheless, novel therapeutic strategies targeting the formation of amyloid fibrils and amyloid deposition may generate new expectations for patients with AA amyloidosis.

Amyloid A amyloidosis in a Japanese patient with familial Mediterranean fever associated with homozygosity for the pyrin variant M694I/M694I

Familial Mediterranean fever (FMF) is an autoinflammatory disease common in eastern Mediterranean populations. The most severe complication is the development of secondary amyloid A (AA) amyloidosis. A 51-year-old Japanese male who had been suffering from periodic fever since in his twenties was referred to our hospital for proteinuria. Histological findings from renal biopsy revealed the deposition of AA amyloid fibrils, suggesting that renal dysfunction was due to AA amyloidosis. Gene analysis of the patient and his mother showed that both were homozygous for the M694I mutation in the MEFV gene. His mother was also a carrier of the SAA1.3 allele, which is not only a univariate predictor of survival but also a risk factor for the association of AA amyloidosis with rheumatoid arthritis in Japanese patients, and the SAA1-13T allele in the 13T/C polymorphism on the 5'-flanking region of the SAA1 gene. The patient was also a carrier of the SAA-13T allele. Colchicine resulted in not only an amelioration of the acute febrile attacks of FMF inflammation, but also an improvement in kidney dysfunction due to AA amyloidosis.

Human SAA1-derived amyloid deposition in cell culture: a consistent model utilizing human peripheral blood mononuclear cells and serum-free medium

Amyloid A (AA) amyloidosis is a fatal disease caused by extracellular deposition of fibrils derived from serum AA (SAA). AA amyloid fibril formation has previously been modeled in macrophage cultures using highly amyloidogenic mouse SAA1.1, but attempts to do the same with human SAA invariably failed. Our objective was to define conditions that support human SAA-derived amyloid formation in peripheral blood mononuclear cell (PBMC) cultures. Two conditions were found to be critical - omission of fetal calf serum and use of StemPro34, a lipid-enriched medium formulated for hematopoietic progenitor cells. Cultures maintained in serum-free StemPro34 and provided with recombinant human SAA1 in the complete absence of amyloid-enhancing factor exhibited amyloid deposition within 7 d. Amyloid co-localized with cell clusters that characteristically included cells of fibrocytic/dendritic morphology as well as macrophages. These cells formed networks that appeared to serve as scaffolding within and upon which amyloid accumulated. Cells in amyloid-forming cultures demonstrated increased adherence, survival and expression of extracellular matrix components. Of the three human SAA1 isoforms, SAA1.3 showed the most extensive amyloid deposition, consistent with it being the most prevalent isoform in Japanese patients with AA amyloidosis. Attesting to the reproducibility and general applicability of this model, amyloid formation has been documented in cultures established from eight PBMC donors.

The contribution of SAA1 polymorphisms to Familial Mediterranean fever susceptibility in the Japanese population

Background/Aims

Familial Mediterranean Fever (FMF) has traditionally been considered to be an autosomal-recessive disease, however, it has been observed that substantial numbers of patients with FMF possess only 1 demonstrable MEFV mutation. The clinical profile of familial Mediterranean fever (FMF) may be influenced by MEFV allelic heterogeneity and other genetic and/or environmental factors.

Methodology/Principal Findings

In view of the inflammatory nature of FMF, we investigated whether serum amyloid A (SAA) and interleukin-1 beta (IL-1β) gene polymorphisms may affect the susceptibility of Japanese patients with FMF. The genotypes of the -13C/T SNP in the 5′-flanking region of the SAA1 gene and the two SNPs within exon 3 of SAA1 (2995C/T and 3010C/T polymorphisms) were determined in 83 Japanese patients with FMF and 200 healthy controls. The same samples were genotyped for IL-1β-511 (C/T) and IL-1 receptor antagonist (IL-1Ra) variable number of tandem repeat (VNTR) polymorphisms. There were no significant differences between FMF patients and healthy subjects in the genotypic distribution of IL-1β -511 (C/T), IL-1Ra VNTR and SAA2 polymorphisms. The frequencies of SAA1.1 allele were significantly lower (21.7% versus 34.0%), and inversely the frequencies of SAA1.3 allele were higher (48.8% versus 37.5%) in FMF patients compared with healthy subjects. The frequency of -13T alleles, associated with the SAA1.3 allele in the Japanese population, was significantly higher (56.0% versus 41.0%, p = 0.001) in FMF patients compared with healthy subjects.

Conclusions/Significance

Our data indicate that SAA1 gene polymorphisms, consisting of -13T/C SNP in the 5′-flanking region and SNPs within exon 3 (2995C/T and 3010C/T polymorphisms) of SAA1 gene, are associated with susceptibility to FMF in the Japanese population.

Variant screening of the serum amyloid A1 gene and functional study of the p.Gly90Asp variant for its role in atherosclerosis

OBJECTIVES

Serum amyloid A1 (SAA1) is a major acute-phase protein that is increasingly used as a reliable predictor of coronary artery disease (CAD). In this study we aim to screen the SAAI promoter and exons for genetic variants and to determine their association with CAD. In addition, we also carried out functional study on a variant of p.Gly90Asp encoded by the SAA1 gene.

METHODS

Variant screening of SAA1 was performed using high resolution melting (HRM) analysis. Genetic association of p.Gly90Asp with CAD was determined in 800 CAD patients and 773 Chinese control subjects. Functional study of p.Gly90Asp was carried out using THP-1-derived macrophages and HL-60 promyelocytic leukemia cells.

RESULTS

A total of 6 SNPs were identified, of which 2 were found to be novel (c.-913G > A and c.92-5T > G). The rare allele of p.Gly90Asp has a lower frequency of 0.013 in the CAD patients although this is not statistically significant. Functional studies of p.Gly90Asp revealed that the variant has decreased upregulation of key cytokines such as IL-8, MCP-1 and TNF-α as well as SERPINB2.

CONCLUSIONS

We found the variant p.Gly90Asp SAA1 protein eliciting significantly reduced inflammatory responses in macrophages through a reduction in the secretion of inflammatory cytokines. Despite strong functional effects, the minor allele frequency is too low in the population to attain statistical significance difference between cases and controls.

Familial Mediterranean fever in Japan

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disease that is prevalent in Mediterranean populations. While it is considered a rare disease in the rest of world, a significant number of FMF patients have been reported in East Asia, including Japan. Our aim was to determine the prevalence of FMF in Japan and elucidate the clinical and genetic features of Japanese patients. A primary nationwide survey of FMF was conducted between January and December 2009. Hospitals specializing in pediatrics and hospitals with pediatric, internal medicine, and rheumatology/allergy departments were asked to report all patients with FMF during the survey year. The estimated total number of Japanese FMF patients was 292 (95% confidence interval, 187-398 people). We evaluated the clinical and genetic profiles of Japanese patients from the data obtained in a secondary survey of 134 FMF patients. High-grade fever was observed in 95.5%, chest pain (pleuritis symptoms) in 36.9%, abdominal pain (peritonitis symptoms) in 62.7%, and arthritis in 31.3%. Of the patients profiled, 25.4% of patients experienced their first attack before 10 years of age, 37.3% in their teens, and 37.3% after age 20 years. Colchicine was effective in 91.8% of patients at a relatively low dose (mean dose, 0.89 ± 0.45 mg/d). AA amyloidosis was confirmed in 5 patients (3.7%). Of the 126 patients studied, 109 (86.5%) were positive for 1 or more genetic mutations and 17 (13.5%) had no mutation detected. Common Mediterranean fever gene (MEFV) mutations were E148Q/M694I (19.8%) and M694I/normal (12.7%). The differences in the prevalence of peritonitis, pleuritis, and a family history of FMF were statistically significant between FMF patients with MEFV exon 10 mutations compared with those without exon 10 mutations.In conclusion, a significant number of patients with FMF exist in Japan. Although Japanese patients with FMF are clinically or genetically different from Mediterranean patients, the delay in diagnosis is an issue that should be resolved.

Effectiveness of etanercept vs cyclophosphamide as treatment for patients with amyloid A amyloidosis secondary to rheumatoid arthritis

OBJECTIVES

To compare the effectiveness of an alkylating agent with that of a biologic agent in the treatment of patients with amyloid A (AA) amyloidosis secondary to RA and to assess the association of the serum AA (SAA) 1.3 allele with treatment.

METHODS

CYC and etanercept (ETN) were administered to 62 and 24 RA patients, respectively, who were confirmed with biopsy as having AA amyloidosis. We evaluated whether the SAA1.3 allele, a factor indicating genetic risk and poor prognosis of Japanese RA patients with AA amyloidosis, influenced treatments and retrospectively analysed the effectiveness of both agents via statistical methods.

RESULTS

Two treatment groups were similar, except for the SAA1.3 genotype (P = 0.015) and duration of AA amyloidosis since diagnosis (P < 0.001). Also, patients given ETN had somewhat worse renal function, i.e. 24-h proteinuria (P = 0.02), at the initiation of treatment. ETN demonstrated greater effectiveness than CYC, as shown by significantly improved levels of serum CRP and serum albumin (both P < 0.01) and estimated glomerular filtration rate (eGFR; P = 0.032). ETN improved survival (P = 0.025), and the hazard ratios for the risk of death endpoint with eGFR and 24-h proteinuria were significant by P = 0.024 and P = 0.025, respectively. The SAA1.3 allele did not affect the response to medications in AA amyloidosis secondary to RA.

CONCLUSION

ETN treatment was more effective than CYC treatment, and CRP, albumin and eGFR may be valuable biomarkers for analysis. The SAA1.3 allele was not a factor affecting treatment in Japanese patients with AA amyloidosis secondary to RA.

Tocilizumab improves cardiac disease in a hemodialysis patient with AA amyloidosis secondary to rheumatoid arthritis

A 58-year-old Japanese woman on hemodialysis (HD) was admitted for intractable rheumatoid arthritis. Even after HD was started due to end-stage renal failure in 2004, her arthropathy worsened. A soluble tumor necrosis factor receptor inhibitor (etanercept at 25 mg twice weekly), tacrolimus (2 mg daily), and prednisolone (10 mg daily) had been administered since 2005, but high disease activity had persisted. She was admitted to our hospital in July 2007. C-reactive protein (CRP) was 6.8 mg/dL, and the DAS-CRP score was calculated to be 8.3. The cardiothoracic ratio (CTR) was 62% on a chest radiograph, but dialysis hypotension was remarkable. Left ventricular mass (LVM) was calculated as 320 g using echocardiography. Endoscopic biopsy of the stomach and duodenum revealed heavy deposition of AA amyloid. Etanercept was discontinued and tocilizumab was started at a dose of 320 mg (8 mg/kg) monthly. Even after predonisolone and tacrolimus were tapered gradually and discontinued because of her good response, CRP and DAS-CRP became 0.0 mg/dL and 1.5, respectively. In September 2011, re-evaluation was performed. CTR was reduced to 51% and LVM was decreased to 180 g. Endoscopic biopsy of the stomach and duodenum revealed disappearance of AA amyloid. Although AA amyloidosis of the gastrointestinal tract has already been reported to be improved by tocilizumab, this is the first report on improvement of myocardial hypertrophy as well as dialysis hypotension.

Concurrent systemic AA amyloidosis can discriminate primary sclerosing cholangitis from IgG4-associated cholangitis

Chronic hepatobiliary inflammatory diseases are not widely acknowledged as underlying disorders of systemic AA amyloidosis, except epidemic schistosomiasis. Among them, primary sclerosing cholangitis (PSC) might initiate amyloid A protein deposition in diverse tissues, giving rise to systemic amyloidosis, due to a progressive and unresolved inflammatory process, and its possible association with inflammatory bowel diseases. Nevertheless, only one such case has been reported in the literature to date. We report a 69-year-old Japanese woman with cirrhosis who was diagnosed with PSC complicated with systemic AA amyloidosis, without any evidence of other inflammatory disorders. As a result of cholestasis in conjunction with biliary strictures and increased serum IgG4, the presence of IgG4⁺ plasma cells was examined systemically, resulting in unexpected documentation of Congo-red-positive amyloid deposits, but not IgG4⁺ plasma cells, in the liver, stomach and salivary glands. Elevated serum IgG4 is the hallmark of IgG4-related disease, including IgG4-associated cholangitis, but it has also been demonstrated in certain patients with PSC. Amyloid A deposits in multiple organs associated with an indolent clinical course that progresses over many years might have a diagnostic value in discriminating PSC from IgG4-associated cholangitis.

Systemic AA amyloidosis

Systemic AA amyloidosis is a rare complication of chronic inflammatory disorders. The amyloid fibrils are derived from serum amyloid A protein, an acute phase protein synthesized in the liver. Clinical presentation is most commonly due to the consequences of renal involvement, with proteinuria and progressive renal decline. Progression to end stage renal failure is common. Management is currently centred on reducing the supply of the precursor protein by treating the underlying inflammatory condition, whilst supporting the affected organs. Monitoring of the serum amyloid A protein is vital to assess whether there is adequate suppression of the underlying disease. The level of serum amyloid A protein is a powerful predictor of both patient survival and renal outcome. In patients with adequate suppression of the serum amyloid A protein amyloid deposits can be seen to regress and renal function can be stabilised and even improve.

Ageing: a risk factor for amyloid A amyloidosis in rheumatoid arthritis

OBJECTIVE

Acceleration of amyloid A (AA) amyloidosis induction by ageing has not been extensively studied in rheumatoid arthritis (RA). The aim of this study is to clarify contribution of ageing to the development of AA amyloidosis associated with RA in our large cohort.

METHODS

388 adult-onset RA patients whose RA was complicated by biopsy-proven AA amyloidosis were enrolled. The ages of RA onset and AA amyloidosis diagnosis were estimated in each patient. The contributions of ageing, inflammatory activity, SAA1 exon 3 polymorphism as well as gender to the pathogenesis of AA amyloidosis in 144 cases were also studied by multiple regression analysis.

RESULTS

Subjects with RA onset at older age had a shorter period to develop amyloidosis than those with disease onset at younger age (p < 0.001). The interval between RA onset and AA amyloidosis diagnosis was significantly shorter in the SAA1.3 positive group than in the SAA1.3 negative (p=0.001). Multiple regression analysis indicated that the interval from RA onset to diagnosis of AA amyloidosis is determined by age at RA onset (p < 0.001), the most recent median annual CRP concentration (p=0.006) and SAA1.3 allele (p=0.058). Gender did not significantly contribute to the onset of AA amyloidosis (p=0.569).

CONCLUSION

Ageing is an independent risk factor for the induction of AA amyloidosis complicating RA.

Antisense oligonucleotide suppression of serum amyloid A reduces amyloid deposition in mice with AA amyloidosis

AA amyloid patients who experience disease progression and develop renal failure have not received sufficient benefit from agents that treat inflammation or infection. We have begun to explore the potential application of antisense oligonucleotides (ASOs) to specifically suppress SAA production and thereby reduce amyloid deposition. Proof-of-concept experiments conducted in mice initially examined ASO ability to reduce serum levels of SAA during an acute inflammatory response. Peak SAA levels in ASO-treated mice were reduced as much as 65% relative to levels in saline-treated mice. The extent of suppression was dose-dependent and influenced by the time interval between ASO administration and inflammatory stimulation. Subsequent experiments tested whether ASO suppression of SAA was sufficient to mitigate amyloid deposition. Amyloidosis was induced by amyloid-enhancing factor and silver nitrate injection; ASO treatment was initiated 1 week later and continued 1× or 3× per week; inflammation was re-triggered by subsequent injection(s) of silver nitrate; mice were sacrificed after 4-5 weeks. Examination of tissues by Congo red staining and SAA/AA immunohistochemistry revealed consistently less amyloid in the organs of ASO-treated mice compared to saline-treated counterparts. These findings provide rationale for further investigation of SAA-specific ASOs as a potential therapy for AA amyloidosis.

Laser Doppler perfusion imaging in systemic sclerosis impaired response to cold stimulation involves digits and hand dorsum

OBJECTIVES

To assess by Laser Doppler perfusion imaging (LDPI) skin blood perfusion of hands in patients with SSc and primary RP (PRP) at baseline and after cold stimulation (CS). In SSc patients, the associations between skin perfusion and nailfold video capillaroscopy (NVC) patterns were also evaluated.

METHODS

Forty patients with SSc, 38 patients with PRP and 32 healthy controls were recruited. Skin blood flow of the hands was detected by Lisca Laser Doppler Perfusion Imager at baseline and after CS. Further laser Doppler scanning was performed for each hand at 0 (T(1)), 3 (T(2)), 7 (T(3)) and 15 min (T(4)).

RESULTS

Baseline mean perfusion is significantly (P < 0.000 l) lower in SSc patients than in healthy controls. In SSc patients, mean perfusion is reduced after CS (P < 0.0001) and skin flow recovery (significant difference between T(0) and T(4), P < 0.0001) is incomplete. In SSc patients with low vascular damage (early and active capillaroscopic groups), the abnormal microvascular response to CS involves only the digits, while the perfusion of hands dorsum is normal. With the progression of vascular damage (late capillaroscopic groups), the abnormal microvascular response to CS also appears in the hand dorsum skin. In PRP patients, baseline hand perfusion is very low and the skin flow recovery after CS is absent (P < 0.05).

CONCLUSION

In early SSc, the thermoregulation of finger skin is impaired, but only in advanced stages of microangiopathy does the skin of the hand dorsum show a vasomotor control failure.

Identification of regions responsible for heparin-induced amyloidogenesis of human serum amyloid A using its fragment peptides

Human serum amyloid A (SAA) is a precursor protein of amyloid fibrils. Although several studies have been performed, a detailed understanding of the molecular mechanism for SAA fibrillation remains elusive. Glycosaminoglycans such as heparin are suggested to serve as scaffolds in amyloid fibril formation in some cases. In the present study, amyloidogenic properties of synthetic fragment peptides corresponding to the N-terminal (residues 1-27), central (residues 43-63), and C-terminal (residues 77-104) regions of SAA molecule induced by heparin were examined using fluorescence, circular dichroism (CD), and electron microscopy. Fluorescence and CD measurements demonstrated that SAA (1-27) peptide is evidently involved in heparin-induced amyloidogenesis. Correspondingly, relatively minor changes in fluorescence and a quite different pattern in the CD spectrum were observed in SAA (43-63) peptide. In contrast, SAA (77-104) peptide did not show any changes induced by heparin. Transmission electron microscopy indicated that SAA (1-27) peptide forms short and straight fibrils, whereas SAA (43-63) peptide forms much longer and seemingly elastic fibrils. These results suggest that the N-terminal region plays a crucial role as a rigid core and the central region facilitates the elongation of fibrils in heparin-induced amyloidogenesis of SAA molecule.

[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.