INTRODUCTION:Liver is frequently involved in AL amyloidosis. Diagnosis usually relies on hepatomegaly and elevated alkaline phosphatase levels. Liver stiffness (LS) at diagnosis and, overall, its follow-up remains to be further explored. MATERIAL AND METHODS:We assessed LS at diagnosis in a retrospective multicenter cohort. Patients were classified as having liver involvement only (group 1), heart involvement only (group 2), both (group 3), or neither (group 4). In a prospective monocentric cohort, we evaluated changes in LS over time. RESULTS:In the retrospective cohort of 56 patients, median LS values were 75 kPa in group 1 (n = 14), 11.6 kPa in group 2 (n = 17), 28.8 kPa in group 3 (n = 13), and 6.4 kPa in group 4 (n = 12). The ROC curve in patients with liver involvement identified an optimal cutoff of 13.6 kPa, with 92% sensitivity and 71% specificity. In the prospective cohort of 19 treated patients, median LS decreased with 91% reduction, 26% reduction, 79% reduction and 19% reduction respectively in groups 1, 2, 3 and 4. CONCLUSION:LS is useful for diagnosing hepatic involvement in amyloidosis. A threshold of 13.6 kPa, in the absence of other etiologies, could be prosposed as diagnostic criteria. A decrease in LS greater than 50% can be a marker of hepatic recovery. Clinically and prognostically significant cutoffs still need to be confirmed in future, larger-scale studies.
BACKGROUND:Systemic amyloidosis is a progressive disease in which misfolded protein toxicity and deposition lead to organ dysfunction. Early diagnosis is essential to enable timely treatment and prevent irreversible organ damage, yet the disease remains underrecognized. Although advances in imaging and biomarkers have raised suspicion in appropriate contexts, a major barrier is the absence of clearly defined factors identifying individuals at high risk who warrant timely screening. METHODS:On behalf of the International Society of Amyloidosis (ISA), experts in the field reviewed the diagnostic landscape and identified unmet needs in the early detection of systemic amyloidosis. RESULTS:The experts highlighted a lack of risk-adapted screening strategies capable of improving detection while avoiding inefficient population-level screening. They identified parameters that may help define high-risk populations, including biomarkers, susceptibility factors, demographic variables, and clinical 'red flags'. They further discussed how artificial intelligence (AI)-driven tools may support identification of at-risk individuals and accelerate diagnosis in suspected amyloidosis. CONCLUSIONS:Defining high-risk populations and integrating AI-based tools may enable risk-adapted screening that improves early diagnosis while avoiding indiscriminate population-level testing.
BACKGROUNDS:Hereditary ATTR amyloidosis with polyneuropathy (ATTRv-PN) frequently presents with gastrointestinal autonomic dysfunction, but its underlying pathology remains unclear. METHODS:We examined gastric mucosal amyloid deposition and innervation using conventional endoscopic biopsies in ATTRv-PN patients and a human TTR (hTTR A117S) knock-in mouse model. Clinical assessments, gut microbiota, metabolomics, and neurite growth assays were integrated. RESULTS:Among 33 patients, 84.8% showed TTR(+) amyloid deposition in gastric mucosa. Gastric mucosal innervation density (GMID) was significantly reduced in all gastric regions compared with controls and was similarly decreased in hTTR(A117S) mice. Lower GMID correlated with gastroparesis and reflux symptom severity. Integrated analyses revealed positive associations between GMID, four microbial genera, and histidine levels. Both microbiota-derived principal components and histidine independently correlated with GMID. Histidine also promoted neurite growth in vitro. CONCLUSIONS:Endoscopic biopsy enables assessment of both gastric amyloid pathology and mucosal innervation in ATTRv-PN. Reduced GMID is closely associated with gastrointestinal symptoms, microbiota alterations, and metabolomic changes, providing insights into disease mechanisms and potential biomarkers of autonomic gastrointestinal dysfunction.
BACKGROUND:Amyloidosis is characterized by hierarchical organ-specific targeting related to the nature and amino acid sequence of the precursor protein. However, several crucial aspects of tissue vulnerability and resilience to amyloid deposition and toxicity remain poorly defined. RESULTS:The amino acid sequence of the amyloid protein is a primary determinant of organ targeting. Cryo-electron microscopy reveals common fibril architectures across organs, indicating interactions with shared tissue constituents. The interaction with the microenvironment, comprising glycosaminoglycans, collagen, endoproteases, and tissue cells, may underlie tissue vulnerability. Cellular interactions involve internalization of amyloid precursors, leading to lysosomal dysfunction, mitochondrial impairment, reactive oxygen species production, and proteotoxicity, particularly in cardiomyocytes and mesangial cells. Increased structural dynamics in amyloidogenic light chains promote improper interactions with cell constituents. Tissue-specific proteostasis capacity declines with age, contributing to tissue vulnerability in elderly patients. Parallels with neurodegenerative diseases underscore selective cellular susceptibility due to proteostatic overload and metabolic stress. CONCLUSIONS:Evidence shows that the amino acid sequence of the amyloid protein, microenvironmental factors, and cell-intrinsic and extracellular proteostatic capacity jointly determine tissue vulnerability and resilience in amyloidosis, with relative contributions varying by amyloid protein. Identifying key determinants provides actionable targets for improving the care of systemic and localized amyloidosis.
BACKGROUND:Hereditary transthyretin (ATTRv) amyloidosis is a systemic disorder caused by extracellular deposition of transthyretin-derived amyloid fibrils. Although gastrointestinal involvement is common, its endoscopic characteristics remain unclear. This study aimed to elucidate the endoscopic and histological features of gastrointestinal ATTRv amyloidosis. METHODS:Between January 2012 and August 2024, 123 patients with histologically and genetically confirmed gastrointestinal ATTRv amyloidosis who underwent esophagogastroduodenoscopy were retrospectively enrolled (GI ATTRv group). As controls, 123 age- and sex-matched individuals without amyloidosis were included. RESULTS:The GI ATTRv group comprised 77 men (62.6%) with a median age of 54 years. Amyloid deposition was most frequently observed in the muscularis mucosae (83.7%). More than half of both groups showed no abnormal endoscopic findings in the stomach (GI ATTRv: 61.8%, control: 62.6%; p = 1) or duodenum (GI ATTRv: 89.4%, control: 95.9%; p = .099). Gastric food residue was significantly more frequent in the GI ATTRv group than in controls (15.4% vs. 0.8%, p < .001). CONCLUSIONS:Gastrointestinal ATTRv amyloidosis was characterized by a lack of specific endoscopic abnormalities. However, gastric food residue may represent a useful indicator of gastrointestinal dysmotility in ATTRv amyloidosis.
BACKGROUND:Patients with transthyretin amyloidosis (ATTR) with cardiomyopathy (CM) can experience extracardiac manifestations, including gastrointestinal (GI) manifestations that negatively impact their quality of life. METHODS:In the double-blind HELIOS-B study, patients received vutrisiran 25 mg or placebo every 12 weeks for up to 36 months. Reported adverse events classified using preferred terms of the MedDRA GI disorders system organ class were compared between treatment arms in the overall population, the monotherapy population (not receiving tafamidis at baseline) and the baseline tafamidis subgroup. RESULTS:Overall, 271/654 patients experienced 529 GI events, 195 in the vutrisiran arm (23.4 events per 100 patient-years) and 334 in the placebo arm (40.6 events/100 patient-years; rate ratio, 0.58; p < 0.0001). With vutrisiran, lower rates were observed for almost all GI events including constipation, diarrhea, nausea, abdominal pain and vomiting, versus placebo, with rates of overall GI events reduced by 38-49% across populations (all p < 0.0001). Reductions in mean cumulative GI events with vutrisiran versus placebo were observed from Month 3. CONCLUSIONS:Treatment with vutrisiran was associated with substantially fewer GI events versus placebo in patients with ATTR-CM, with the difference beginning early in treatment. Future trials should consider assessment of extracardiac manifestations.
BACKGROUND:Advances in disease-modifying therapies for hereditary transthyretin (ATTRv) amyloidosis have improved long-term survival. As a result, central nervous system (CNS) involvement, particularly leptomeningeal amyloidosis and cerebral amyloid angiopathy, is increasingly encountered in V30M (p.V50M) patients. However, the frequency, distribution, and progression of CNS involvement on MRI remain unclear. METHODS:We retrospectively analyzed patients with ATTR V30M amyloidosis who underwent brain MRI with gadolinium-enhanced FLAIR (Gd-FLAIR) or susceptibility-weighted imaging (SWI) between 2010 and 2025. Associations between leptomeningeal enhancement, cerebral microbleeds, and clinical parameters were evaluated. RESULTS:Leptomeningeal enhancement on Gd-FLAIR was observed in 13/44 patients (29.5%); disease duration was longer in patients with enhancement than in those without (15.0 [8.9-22.8] vs. 5.2 [2.4-10.5] years, p < 0.001). The semiquantitative Gd-FLAIR score correlated with disease duration (rs = 0.56, p < 0.001). In contrast, cerebral microbleeds were not associated with disease duration or progression. Leptomeningeal enhancement appeared as focal surface lesions in early stages and became diffuse in advanced stages, predominantly involving the posterior fossa. CONCLUSIONS:Leptomeningeal enhancement on Gd-FLAIR MRI is a frequent and progressive finding associated with disease duration and may precede cerebral microbleeds, supporting its role as an early and sensitive marker in ATTR V30M amyloidosis.
INTRODUCTION:Subcutaneous fat aspiration is a minimally-invasive screening tool for systemic amyloidosis (SA) with high variability in reported sensitivities. METHODS:Sensitivity and specificity were studied for consecutive Congo red-stained fat aspirates for amyloidosis screening performed between 2013 and 2020. For sensitivity analysis patients with symptomatic SA proven by either histopathology or scintigraphy and for specificity analysis patients with clinically certain exclusion of SA were chosen. Deposits were classified as substantial when >10% of analyzed tissue stained positive. RESULTS:1320/2830 probes were positive of which 617 were graded as substantial.Overall sensitivity was 70.0% (1190/1701) according to gold-standard and specificity was 99.4% (613/617). Additionally, in 110/114 patients with clinically certain SA and in 16/398 probes from patients with nonspecific findings amyloid was detected. For subtypes, sensitivities were: systemic light-chain (AL) 90.1% (922/1023), transthyretin wild-type (ATTRwt) 18.8% (69/368), AA 72.3% (107/148) and transthyretin variant (ATTRv) amyloidosis 71% (63/89). Sensitivity overall and in AL, ATTRwt, AA and ATTRv was higher in females. Substantial deposits were more common in females overall and in AL. SUMMARY:Fat aspiration for symptomatic SA yielded excellent specificity. Sensitivity was very good in AL and fair in ATTRv and AA amyloidosis. Sensitivity was higher in females than in males.
BACKGROUND:The vascular effects of wild-type (ATTRwt-CM) and hereditary (ATTRv-CM) transthyretin cardiac amyloidosis, and the impact of tafamidis treatment, remain unclear. METHODS:Serum from ATTRwt-CM and ATTRv-CM patients (pre- and 6-months post-Tafamidis treatment) elderly and young controls, was applied on human umbilical vein endothelial cells (HUVECs). Viability, motility, and stress responses and serum cytokine and proteomic profiles were assessed. Recombinant TTR, with and without tafamidis co-treatment, were also evaluated. Pulse wave velocity (PWV) was longitudinally assessed in ATTRwt-CM patients pre- and post-tafamidis treatment and in elderly controls. RESULTS:ATTRwt-CM or ATTRv serum reduced HUVECs viability and motility, inducing proteotoxic and oxidative stress, while serum cytokine and proteome profiling revealed inflammatory-related signatures; All these effects were attenuated in HUVECs treated with post-Tafamidis serum. Recombinant TTR also induced proteotoxic stress, which was attenuated by tafamidis co-treatment (safety range ≤ 16 μM). Consistently, PWV was reduced in ATTRwt-CM patients after Tafamidis, as compared to controls, correlating with increased serum transthyretin and reduced PBMCs' proteasome activity. CONCLUSIONS:Serum from ATTR-CM patients or recombinant TTR directly induced toxic effects in HUVECs. Tafamidis mitigated these effects in vitro and improved arterial stiffness in ATTRwt-CM patients, implying protective vascular effects of tafamidis in ATTR-CM beyond direct myocardial transthyretin stabilization.
BACKGROUND:The long-term efficacy and safety of vutrisiran in hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) were assessed in the HELIOS-A randomized treatment extension (RTE). METHODS:Patients who completed the 18-month, phase 3, open-label HELIOS-A study could enter an open-label RTE with re-randomization 1:1 to vutrisiran 25 mg every 3 months (Q3M) or 50 mg every 6 months (Q6M; transitioned to 25 mg Q3M following an amendment) for up to 42 months (RTE M18 efficacy assessment; RTE M42 safety and transthyretin (TTR) levels). RESULTS:In the RTE, 149 patients were re-randomized to vutrisiran (25 mg Q3M [n = 76]; 50 mg Q6M [n = 73]). Mean serum TTR reduction from study baseline at RTE M42 for the total vutrisiran group was 84.5%. Efficacy was sustained from RTE baseline through RTE M18 in modified Neuropathy Impairment Score +7, Norfolk Quality of Life-Diabetic Neuropathy score, 10-meter walk test, Rasch-built Overall Disability Scale and modified body mass index (mBMI); most patients (67.8%) had stable polyneuropathy disability scores. Most AEs were mild/moderate in severity with no new safety concerns. CONCLUSIONS:Results from the HELIOS-A RTE demonstrate relative stability with only modest changes in disease activity, sustained serum TTR reductions, and an acceptable safety profile with long-term vutrisiran treatment in patients with ATTRv-PN. ClinicalTrials.gov: NCT03759379.
BACKGROUND:Systemic light chain amyloidosis is a protein misfolding disorder characterized by deposition of clonal immunoglobulin light chains in vital organs. To date, little is known about the contribution of light chain constant domain mutations in thermodynamic stability and amyloidogenicity. METHODS:In 89 patients, RNA-based full-length light chain repertoire sequencing with Oxford Nanopore was performed, in addition to Illumina sequencing and mass spectrometric detection of light chain protein in serum and amyloid deposits. Computational methods for conservation, free energy calculation and molecular dynamics simulations were applied to investigate the thermodynamic stability. RESULTS:Monoclonal light chain detection rate was 95.4%, and sequences showed 100% identity with Illumina in all patients. Light chain protein was specifically detectable by mass spectrometry in serum and amyloid deposits. Lambda constant domain mutations were present in 10%, while no kappa constant domain mutations were detected. Fold free energy change and molecular dynamics simulations indicate potential light chain stabilizing or destabilizing effects of detected constant domain mutations. CONCLUSION:Current findings highlight the importance of routinely implementing full-length light chain sequencing in plasma cell dyscrasias, particularly light chain amyloidosis to account for the potential impact of constant domain mutations on light chain stability and amyloidogenicity.
BACKGROUND:Hereditary transthyretin-related (ATTRv) amyloidosis may involve the central nervous system (CNS) years after liver transplantation, causing transient focal neurological episodes (TFNEs). Their mechanisms and electrophysiological correlates remain unclear. METHODS:We retrospectively analyzed 155 patients with ATTRV30M (p.V50M) amyloidosis patients who underwent liver transplantation and had at least one electroencephalogram (EEG). TFNEs were categorized into five clinical subtypes. EEGs from outpatient and hospital settings were included. RESULTS:TFNEs occurred in 76.8% of patients, most commonly as seizure-like (37.0%), transient ischemic attack-like (25.2%) or migraine-like (24.4%) episodes. Stroke-like TFNEs and bilateral tonic-clonic seizures were rarely the initial presentation (13.4%). Anti-seizure medications were prescribed to 77.3% of patients with TFNEs and 26.9% required two or more drugs. Focal slow EEG activity was detected in 40.0% of patients and was associated with TFNEs (OR = 2.91) and reduced survival (HR = 2.18). During acute TFNEs, focal slowing predominated, whereas epileptiform patterns were infrequent (19.5%). Cognitive impairment correlated with posterior dominant rhythm slowing and focal slow activity, particularly in language and executive domains. CONCLUSIONS:TFNEs are common after liver transplantation in ATTRv amyloidosis. Focal slow EEG activity may indicate advanced CNS amyloid deposition, cognitive impairment and poorer prognosis.
BACKGROUND:Diflunisal has been shown to slow the progression of hereditary transthyretin (ATTRv) amyloidosis. We examined the efficacy of diflunisal using data from SveATTR, a longitudinal Swedish registry open for patients with ATTR amyloidosis. METHODS:Data from diflunisal treated patients registered in SveATTR through Dec 2022 were included. Available data on Kumamoto score, PND score/FAP stage, mBMI, NYHA classification and Karnofsky performance status were analyzed using random coefficients mixed effects modeling, and the results were combined with those of the pivotal diflunisal trial. RESULTS:In total, 118 registry subjects were included. Estimated mean time of diflunisal therapy was 3.4 (range 0.1 to 10.2) years. Random coefficients mixed effects modeling demonstrated gradual progression of disease over time by upward trend of Kumamoto score, PND score and FAP stage, and downward trend in Karnofsky score and mBMI while NYHA class score remained unchanged. A Bayesian augmentation analysis was undertaken using registry data and pivotal trial data. After 24 months, the probability of superiority for diflunisal over placebo was 99.6% and 97.2% for Kumamoto score and mBMI, respectively. CONCLUSIONS:SveATTR registry data align with the results of the pivotal trial, providing long-term real-world evidence that confirm the efficacy of diflunisal for ATTRv amyloidosis.
BACKGROUND:Systemic amyloidosis is a chronic, devastating illness caused by the build-up of misfolded proteins, leading to abdominothoracic organ dysfunction. Currently approved treatment options focus on preventing further amyloid accumulation. As such, there is a clinically unmet need for therapeutics that can opsonize tissue-deposited amyloid for clearance by phagocytic cells. We have developed a class of polybasic peptides that bind conserved properties of amyloid and amyloid-associated hypersulfated heparan sulfate, with high specificity. We have generated a novel structural class of polybasic peptides (termed PxR peptides) based on a proline-rich repeat strategy that demonstrates potency against amyloid. METHODS:Amyloid-reactivity and specificity were probed using amyloid-laden and control tissue sections from mice and humans. Amyloid binding to synthetic fibrils and human patient-derived amyloid extracts was quantified using immunosorbent assays. PxR peptide stability in mouse and human serum was quantified using a bioactivity assay. RESULTS:PxR peptides were predicted to form a linear face of positive charges, which can bind with high specificity and potency to synthetic fibrils and amyloid extracts, and are resistant to serum proteases. CONCLUSIONS:Polybasic PxR peptides offer additional resources as pan-amyloid binding peptides for effective delivery of bioactive and amyloid-clearing therapeutics to amyloid.
BACKGROUND:Amyloid transthyretin cardiomyopathy (ATTR-CM) results from extracellular deposition of misfolded transthyretin (TTR), causing progressive heart failure. Naturally-occurring antibodies (nAbs) targeting misfolded proteins exist in neurodegenerative disease, but their presence in ATTR-CM is unknown. The objective of this study is to determine whether nAbs against TTR (nAbsTTR) exist in humans and whether they are influenced by disease or its treatment. METHODS:Serum from healthy donors, umbilical cord blood (UCB), and patients with ATTR-CM - both untreated and receiving TTR-stabilizing therapy - was analyzed for nAbsTTR using immunoassays, blotting, and binding studies. Functional activity was evaluated in a fibril formation assay. RESULTS:nAbsTTR binding both native and amyloid TTR (ATTR) with high affinity (KD 30 nM/7 nM) were detected in healthy serum and UCB. NAbsTTR levels were significantly altered in ATTR-CM compared to controls: nAbsTTR (IgG) were higher while nAbsTTR (IgM) were lower. nAbsTTR of both subtypes significantly increased by 22% (p ≤ 0.05) in patients receiving TTR-stabilizing therapy. In vitro, nAbsTTR suppressed TTR fibril aggregation. CONCLUSIONS:Naturally-occurring TTR-targeting antibodies are present from birth, modulated by disease and therapy, and inhibit fibril formation. These findings reveal an unrecognized immune mechanism with potential relevance for ATTR-CM pathogenesis and treatment.
