Systemic AA amyloidosis is a worldwide occurring protein misfolding disease of humans and animals. It arises from the formation of amyloid fibrils from the acute phase protein serum amyloid A. Here, ...we report the purification and electron cryo-microscopy analysis of amyloid fibrils from a mouse and a human patient with systemic AA amyloidosis. The obtained resolutions are 3.0 Å and 2.7 Å for the murine and human fibril, respectively. The two fibrils differ in fundamental properties, such as presence of right-hand or left-hand twisted cross-β sheets and overall fold of the fibril proteins. Yet, both proteins adopt highly similar β-arch conformations within the N-terminal ~21 residues. Our data demonstrate the importance of the fibril protein N-terminus for the stability of the analyzed amyloid fibril morphologies and suggest strategies of combating this disease by interfering with specific fibril polymorphs.
Systemic AA amyloidosis is a debilitating protein misfolding disease in humans and animals. In humans, it occurs in two variants that are called 'vascular' and 'glomerular', depending on the main ...amyloid deposition site in the kidneys. Using cryo electron microscopy, we here show the amyloid fibril structure underlying the vascular disease variant. Fibrils purified from the tissue of such patients are mainly left-hand twisted and contain two non-equal stacks of fibril proteins. They contrast in these properties to the fibrils from the glomerular disease variant which are right-hand twisted and consist of two structurally equal stacks of fibril proteins. Our data demonstrate that the different disease variants in systemic AA amyloidosis are associated with different fibril morphologies.
Purpose
Cardiac transthyretin-related amyloidosis (ATTR) is a progressive and fatal cardiomyopathy. The diagnosis of this disease is frequently delayed or missed due to the limited specificity of ...echocardiography. An increasing amount of data in the literature demonstrate the ability of bone scintigraphy with bone-seeking radiopharmaceuticals to detect myocardial amyloid deposits, in particular in patients with ATTR. Therefore we performed a systematic review and bivariate meta-analysis of the diagnostic accuracy of bone scintigraphy in patients with suspected cardiac ATTR.
Methods
A comprehensive computer literature search of studies published up to 30 November 2017 on the role of bone scintigraphy in patients with ATTR was performed using the following search algorithm: (a) “amyloid” OR “amyloidosis” AND (b) “TTR” OR “ATTR” OR “transthyretin” AND (c) “scintigraphy” OR “scan” OR “SPECT” OR “SPET” OR “bone” OR “skeletal” OR “skeleton” OR “PYP” OR “DPD” OR “HMDP” OR “MDP” OR “HDP”. Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR−) and diagnostic odds ratio (DOR) of bone scintigraphy were calculated.
Results
The meta-analysis of six selected studies on bone scintigraphy in cardiac ATTR including 529 patients provided the following results: sensitivity 92.2% (95% CI 89–95%), specificity 95.4% (95% CI 77–99%), LR+ 7.02 (95% CI 3.42–14.4), LR− 0.09 (95% CI 0.06–0.14), and DOR 81.6 (95% CI 44–153). Mild heterogeneity was found among the selected studies.
Conclusion
Our evidence-based data demonstrate that bone scintigraphy using technetium-labelled radiotracers provides very high diagnostic accuracy in the non-invasive assessment of cardiac ATTR.
Peripheral and autonomic neuropathy are common disease manifestations in systemic amyloidosis. The neurofilament light chain (NfL), a neuron-specific biomarker, is released into the blood and ...cerebrospinal fluid after neuronal damage. There is a need for an early and sensitive blood biomarker for polyneuropathy, and this systematic review provides an overview on the value of NfL in the early detection of neuropathy, central nervous system involvement, the monitoring of neuropathy progression, and treatment effects in systemic amyloidosis. A literature search in PubMed, Embase, and Web of Science was performed on 14 February 2024 for studies investigating NfL levels in patients with systemic amyloidosis and transthyretin gene-variant (
v) carriers. Only studies containing original data were included. Included were thirteen full-text articles and five abstracts describing 1604 participants: 298 controls and 1306
v carriers or patients with or without polyneuropathy. Patients with polyneuropathy demonstrated higher NfL levels compared to healthy controls and asymptomatic carriers. Disease onset was marked by rising NfL levels. Following the initiation of transthyretin gene-silencer treatment, NfL levels decreased and remained stable over an extended period. NfL is not an outcome biomarker, but an early and sensitive disease-process biomarker for neuropathy in systemic amyloidosis. Therefore, NfL has the potential to be used for the early detection of neuropathy, monitoring treatment effects, and monitoring disease progression in patients with systemic amyloidosis.
Amyloidosis: a clinical overview Hazenberg, Bouke P C
Rheumatic diseases clinics of North America
39, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Amyloidosis is the name for protein-folding diseases characterized by extracellular deposition of a specific soluble precursor protein that aggregates in the form of insoluble fibrils. The ...classification of amyloidosis is based on the chemical characterization of the precursor protein. Deposition of amyloid is localized or systemic. The 4 main types of systemic amyloidosis are AL, AA, ATTR, and Aβ2M type. A schematic approach is proposed for the clinical management of systemic amyloidosis. The importance of typing amyloid with confidence, the usefulness of imaging techniques, the principles of treatment, and the need for well-planned treatment monitoring during follow-up are discussed.
A wide range of rare diseases can have fiscal impacts on government finances that extend beyond expected healthcare costs. Conditions preventing people from achieving national lifetime work averages ...will influence lifetime taxes paid and increase the likelihood of dependence on public income support. Consequently, interventions that influence projected lifetime work activity, morbidity and mortality can have positive and negative fiscal consequences for government. The aim of this study was to apply a public economic framework to a rare disease that takes into consideration a broad range of costs that are relevant to government in relation to transfers received and taxes paid. As a case study we constructed a simulation model to calculate the fiscal life course of an individual with hereditary transthyretin-mediated (hATTR) amyloidosis in The Netherlands. In this lethal disease different progressive disease scenarios occur, including polyneuropathy and/or cardiomyopathy.
Due to progressive disability, health care resource use, and early death, hATTR amyloidosis with polyneuropathy receives more transfers from government compared to the general population. In a scenario where a patient is diagnoses with hATTR at age 45, an individual pays €180,812 less in lifetime taxes and receives incrementally €111,695 in transfers from the government, compared to a person without hATTR. Patients suffering from cardiomyopathy die after median 4 years. The health costs of this scenario are therefore lower than that of the other polyneuropathy-based scenarios.
The fiscal analysis illustrates how health conditions influence not only health costs, but also the cross-sectorial public economic burden attributed to lost tax revenues and public disability allowances. Due to the progressive nature of hATTR amyloidosis used in this study, public costs including disability increase as the disease progresses with reduced lifetime taxes paid. The results indicate that halting disease progression early in the disease course would generate fiscal benefits beyond health benefits for patients. This analysis highlights the fiscal consequences of diseases and the need for broader perspectives applied to evaluate health conditions. Conventional cost-effectiveness framework used by many health technology assessment agencies have well-documented limitations in the field of rare diseases and fiscal modeling should be a complementary approach to consider.
Cardiac amyloidosis is emerging as an underdiagnosed cause of heart failure and mortality. Growing literature suggests that a noninvasive diagnosis of cardiac amyloidosis is now feasible. However, ...the diagnostic criteria and utilization of imaging in cardiac amyloidosis are not standardized. In this paper, Part 2 of a series, a panel of international experts from multiple societies define the diagnostic criteria for cardiac amyloidosis and appropriate utilization of echocardiography, cardiovascular magnetic resonance imaging, and radionuclide imaging in the evaluation of patients with known or suspected cardiac amyloidosis.
To study effectiveness of surgery and watchful waiting in localized laryngeal amyloidosis, retrospective case series. This retrospective study comprises all consecutive patients with localized ...laryngeal amyloidosis surgically treated in a tertiary hospital between 1994 and February 2016. Recurrence rate, revision surgery, progression to systemic amyloidosis, and changes in voice were monitored yearly. Eighteen patients were included. Seven women and eleven men had a median age 50 years (range 21–77 years) and median follow-up 6.4 years (2.4–17 years). Amyloid was located in subglottis (5), glottis (8), false vocal folds (8) and other supraglottic areas (5), in more than one laryngeal region (13) and bilaterally (12). Cold steel excision was used at the glottis; CO
2
laser excision, sometimes assisted by microdebrider, at other laryngeal areas. Eleven patients needed revision surgery, ten within the first 4 years after surgical treatment. One patient needed his first revision surgery after 11 years. Five patients needed a second revision within 6 years after initial diagnosis. Two patients needed a third revision. Indications for first revision surgery were progression (8) with dysphonia (7), dyspnea (2), dysphagia (1), exclusion of malignancy (1), and aphonia (1). No patient developed systemic amyloidosis during follow-up. Although local progression of amyloid necessitates revision surgery once or twice in the first 4–6 years, progression slows down thereafter. Late progression, however, remains possible.
From a clinical perspective, there is a need for a reliable and comprehensive list of diseases causing AA amyloidosis. This list could guide clinicians in the evaluation of patients with AA ...amyloidosis in whom an obvious cause is lacking. In this systematic review, a PubMed, Embase and Web of Science literature search were performed on causes of AA amyloidosis published in the last four decades. Initially, 4066 unique titles were identified, but only 795 full-text articles and letters were finally selected for analysis. Titles were excluded because of non-AA type of amyloidosis, language, no full-text publication or irrelevance. Hundred and fifty diseases were initially reported to be associated with the development of AA amyloidosis. The presence of AA amyloid was proven in 208 articles (26% of all) of which 140 (67%) showed a strong association with an underlying disease process. Disease associations were categorized and 48 were listed as strong, 19 as weak, 23 as unclear, and 60 as unlikely. Most newly described diseases are not really unexpected because they often cause longstanding inflammation. Based on the spectrum of identified causes, a pragmatic diagnostic approach is proposed for the AA amyloidosis patient in whom an obvious underlying disease is lacking.
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