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European Journal of Medicinal Chemistry Dec 2023The aggregation of wild-type transthyretin (TTR) and over 130 genetic TTR variants underlies a group of lethal disorders named TTR amyloidosis (ATTR). TTR chemical...
The aggregation of wild-type transthyretin (TTR) and over 130 genetic TTR variants underlies a group of lethal disorders named TTR amyloidosis (ATTR). TTR chemical chaperones are molecules that hold great promise to modify the course of ATTR progression. In previous studies, we combined rational design and molecular dynamics simulations to generate a series of TTR selective kinetic stabilizers displaying exceptionally high affinities. In an effort to endorse the previously developed molecules with optimal pharmacokinetic properties, we conducted structural design optimization, leading to the development of PITB. PITB binds with high affinity to TTR, effectively inhibiting tetramer dissociation and aggregation of both the wild-type protein and the two most prevalent disease-associated TTR variants. Importantly, PITB selectively binds and stabilizes TTR in plasma, outperforming tolcapone, a drug currently undergoing clinical trials for ATTR. Pharmacokinetic studies conducted on mice confirmed that PITB exhibits encouraging pharmacokinetic properties, as originally intended. Furthermore, PITB demonstrates excellent oral bioavailability and lack of toxicity. These combined attributes position PITB as a lead compound for future clinical trials as a disease-modifying therapy for ATTR.
Topics: Mice; Animals; Prealbumin; Amyloid Neuropathies, Familial; Tolcapone; Molecular Dynamics Simulation
PubMed: 37837673
DOI: 10.1016/j.ejmech.2023.115837 -
Zhonghua Bing Li Xue Za Zhi = Chinese... Jul 2023To investigate the histological features and clinical manifestations in different types of cardiac amyloidosis to improve diagnostic accuracy. The histopathological... (Review)
Review
To investigate the histological features and clinical manifestations in different types of cardiac amyloidosis to improve diagnostic accuracy. The histopathological features and clinical manifestations of 48 patients diagnosed with cardiac amyloidosis by Congo red stain and electron microscopy through endomyocardial biopsy were collected in West China Hospital of Sichuan University from January 2018 to December 2021. Immunohistochemical stains for immunoglobulin light chains (κ and λ) and transthyretin protein were carried out, and a review of literature was made. The patients age ranged from 42 to 79 years (mean 56 years) and the male to female ratio was 1.1 to 1.0. The positive rate of endomyocardial biopsy was 97.9% (47/48), which was significantly higher than that of the abdominal wall fat (7/17). Congo red staining and electron microscopy were positive in 97.9% (47/48) and 93.5% (43/46), respectively. Immunohistochemical stains showed 32 cases (68.1%) were light chain type (AL-CA), including 31 cases of AL-λ type and 1 case of AL-κ type; 9 cases (19.1%) were transthyretin protein type (ATTR-CA); and 6 cases (12.8%) were not classified. There was no significant difference in the deposition pattern of amyloid between different types (>0.05). Clinical data showed that ATTR-CA patients had less involvement of 2 or more organs and lower N-terminal pro-B-type natriuretic peptide (NT-proBNP) than the other type patients (<0.05). The left ventricular stroke volume and right ventricular ejection fraction of ATTR-CA patients were better than the other patients (<0.05). Follow-up data of 45 patients was obtained, and the overall mean survival time was 15.6±2.0 months. Univariate survival analysis showed that ATTR-CA patients had a better prognosis, while cardiac amyloidosis patients with higher cardiac function grade, NT-proBNP >6 000 ng/L, and troponin T >70 ng/L had a worse prognosis (<0.05). Multivariate survival analysis showed that NT-proBNP and cardiac function grade were independent prognostic factors for cardiac amyloidosis patients. AL-λ is the most common type of cardiac amyloidosis in this group. Congo red staining combined with electron microscopy can significantly improve the diagnosis of cardiac amyloidosis. The clinical manifestations and prognosis of each type are different and can be classified based on immunostaining profile. However, there are still a few cases that cannot be typed; hence mass spectrometry is recommended if feasible.
Topics: Humans; Male; Female; Adult; Middle Aged; Aged; Prealbumin; Stroke Volume; Cardiomyopathies; Congo Red; Ventricular Function, Right; Amyloidosis; Prognosis
PubMed: 37408396
DOI: 10.3760/cma.j.cn112151-20221230-01082 -
European Journal of Nuclear Medicine... Dec 2023Transthyretin (ATTR) amyloidosis is a progressive protein misfolding disease with frequent cardiac involvement. This review aims to determine the value of PET in... (Review)
Review
PURPOSE
Transthyretin (ATTR) amyloidosis is a progressive protein misfolding disease with frequent cardiac involvement. This review aims to determine the value of PET in diagnosis, assessment of disease progression or treatment response and its relation to clinical outcome in follow-up of ATTR amyloid cardiomyopathy (ATTR-CM) patients.
METHODS
Medline, Cochrane Library, Embase and Web of Science databases were searched, from the earliest date available until December 2022, for studies investigating the use of PET in ATTR-CM patients. Studies containing original data were included, except for case reports. Risk of bias was assessed by QUADAS-2.
RESULTS
Twenty-one studies were included in this systematic review, investigating five different tracers: carbon-11 Pittsburgh compound B ([C]PIB), fluorine-18 Florbetaben ([F]FBB), fluorine-18 Florbetapir ([F]FBP), fluorine-18 Flutemetamol ([F]FMM) and fluorine-18 Sodium Fluoride (Na[F]F). In total 211 ATTR amyloidosis patients were included. A majority of studies concluded that [C]PIB, [F]FBP and Na[F]F can distinguish ATTR amyloidosis patients from controls, and that [C]PIB and Na[F]F, but not [F]FBP, can distinguish ATTR-CM patients from patients with cardiac light chain amyloidosis. Evidence on the performance of [F]FBB and [F]FMM was contradictory. No studies on the use of PET in follow-up were found.
CONCLUSION
[C]PIB, Na[F]F and [F]FBP can be used to diagnose cardiac amyloidosis, although [F]FBP may not be suitable for the distinction of different types of amyloid cardiomyopathy. No studies on PET in the follow-up of ATTR amyloidosis patients were found. Future research should focus on the use of these PET tracers in the follow-up of ATTR amyloidosis patients.
Topics: Humans; Prealbumin; Follow-Up Studies; Amyloidosis; Positron-Emission Tomography; Cardiomyopathies
PubMed: 37561144
DOI: 10.1007/s00259-023-06381-3 -
Journal of the American Heart... Feb 2024Transthyretin cardiac amyloidosis (ATTR-CA) is a progressive and ultimately fatal cardiomyopathy. Biomarkers reflecting multiorgan dysfunction are of increasing...
BACKGROUND
Transthyretin cardiac amyloidosis (ATTR-CA) is a progressive and ultimately fatal cardiomyopathy. Biomarkers reflecting multiorgan dysfunction are of increasing importance in patients with heart failure; however, their significance in ATTR-CA remains largely unknown. The aims of this study were to characterize the multifaceted nature of ATTR-CA using blood biomarkers and assess the association between blood biomarkers and prognosis.
METHODS AND RESULTS
This is a retrospective cohort study of 2566 consecutive patients diagnosed with ATTR-CA between 2007 and 2023. Anemia (39%), high urea (52%), hyperbilirubinemia (18%), increased alkaline phosphatase (16%), increased CRP (C-reactive protein; 27%), and increased troponin (98.2%) were common findings in the overall population, whereas hyponatremia (6%) and hypoalbuminemia (2%) were less common. These abnormalities were most common in patients with p.(V142I) hereditary ATTR-CA, and became more prevalent as the severity of cardiac disease increased. Multivariable Cox regression analysis demonstrated that anemia (hazard ratio [HR], 1.19 [95% CI, 1.04-1.37]; =0.01), high urea (HR, 1.23 [95% CI, 1.04-1.45]; =0.01), hyperbilirubinemia (HR, 1.32 [95% CI, 1.13-1.57; =0.001), increased alkaline phosphatase (HR, 1.20 [95% CI, 1.01-1.42; =0.04), hyponatremia (HR, 1.65 [95% CI, 1.28-2.11]; <0.001), and troponin-T >56 ng/L (HR, 1.72 [95% CI, 1.46-2.03]; <0.001) were all independently associated with mortality in the overall population. The association between biomarkers and mortality varied across the spectrum of genotypes and left ventricular ejection fraction, with anemia remining independently associated with mortality in p.(V142I) hereditary ATTR-CA (HR, 1.58 [95% CI, 1.17-2.12]; =0.003) and in a subgroup of the overall population with a left ventricular ejection fraction ≤40% (HR, 1.39 [95% CI, 1.08-1.81]; =0.01).
CONCLUSIONS
Cardiac and noncardiac biomarker abnormalities were common and reflect the complex and multifaceted nature of ATTR-CA, with a wide range of biomarkers remaining independently associated with mortality. Clinical trials are needed to investigate whether biomarker abnormalities represent modifiable risk factors that if specifically targeted could improve outcomes.
Topics: Humans; Prealbumin; Cardiomyopathies; Amyloid Neuropathies, Familial; Stroke Volume; Retrospective Studies; Alkaline Phosphatase; Hyponatremia; Ventricular Function, Left; Prognosis; Biomarkers; Anemia; Hyperbilirubinemia; Urea
PubMed: 38314569
DOI: 10.1161/JAHA.123.033094 -
Journal of Integrative Neuroscience Nov 2023Transthyretin (TTR) is secreted by hepatocytes, retinal pigment epithelial cells, pancreatic α and β cells, choroid plexus epithelium, and neurons under stress. The... (Review)
Review
Transthyretin (TTR) is secreted by hepatocytes, retinal pigment epithelial cells, pancreatic α and β cells, choroid plexus epithelium, and neurons under stress. The choroid plexus product is the main transporter of the thyroid hormone thyroxine (T4) to the brain during early development. TTR is one of three relatively abundant cerebrospinal fluid (CSF) proteins (Apolipoprotein J [ApoJ] (also known as clusterin), Apolipoprotein E [ApoE], and TTR) that interact with Aβ peptides , in some instances inhibiting their aggregation and toxicity. It is now clear that clusterin functions as an extracellular, and perhaps intracellular, chaperone for many misfolded proteins and that variation in its gene () is associated with susceptibility to sporadic Alzheimer's disease (AD). The function of ApoE in AD is not yet completely understood, although the allele has the strongest genetic association with the development of sporadic late onset AD. Despite and evidence of the interaction between TTR and Aβ, genomewide association studies including large numbers of sporadic Alzheimer's disease patients have failed to show significant association between variation in the gene and disease prevalence. Early clinical studies suggested an inverse relationship between CSF TTR levels and AD and the possibility of using the reduced CSF TTR concentration as a biomarker. Later, more extensive analyses indicated that CSF TTR concentrations may be increased in some patients with AD. While the observed changes in TTR may be pathogenetically or biologically interesting because of the inconsistency and lack of specificity, they offered no benefit diagnostically or prognostically either independently or when added to currently employed CSF biomarkers, i.e., decreased Aβ1-42 and increased Tau and phospho-Tau. While some clinical data suggest that increases in CSF TTR may occur early in the disease with a significant decrease late in the course, without additional, more granular data, CSF TTR changes are neither consistent nor specific enough to warrant their use as a specific AD biomarker.
Topics: Humans; Alzheimer Disease; Clusterin; Prealbumin; Apolipoproteins E; Biomarkers; Amyloid beta-Peptides
PubMed: 38176942
DOI: 10.31083/j.jin2206158 -
Blood Nov 2023Hereditary transthyretin amyloidosis (ATTRv) is a rare autosomal dominant adult-onset disorder caused by point mutations in the transthyretin (TTR) gene encoding TTR,...
Hereditary transthyretin amyloidosis (ATTRv) is a rare autosomal dominant adult-onset disorder caused by point mutations in the transthyretin (TTR) gene encoding TTR, also known as prealbumin. ATTRv survival ranges from 3 to 10 years, and peripheral nervous system and heart are usually the 2 main tissues affected, although central nervous system and eye may also be involved. Because the liver is the main TTR protein secretor organ, it has been the main target of treatments developed these last years, including liver transplantation, which has been shown to significantly increase survival in a subset of patients carrying the so-called "early-onset Val30Met" TTR gene mutation. More recently, treatments targeting hepatic TTR RNA have been developed. Hepatic TTR RNA targeting is performed using RNA interference (RNAi) and antisense oligonucleotide (ASO) technologies involving lipid nanoparticle carriers or N-acetylgalactosamine fragments. RNAi and ASO treatments induce an 80% decrease in TTR liver production for a period of 1 to 12 weeks. ASO and RNAi phase 3 trials in patients with TTR-related polyneuropathy have shown a positive impact on neuropathy clinical scores and quality of life end points, and delayed RNAi treatment negatively affects survival. Clinical trials specifically investigating RNAi therapy in TTR cardiomyopathy are underway. Hepatic RNA targeting has revolutionized ATTRv treatment and may allow for the transforming a fatal disease into a treatable disorder. Because retina and choroid plexus secrete limited quantities of TTR protein, both tissues are now seen as the next targets for fully controlling the disease.
Topics: Adult; Humans; Oligonucleotides, Antisense; RNA Interference; Quality of Life; CRISPR-Cas Systems; Amyloid Neuropathies, Familial; Oligonucleotides; RNA
PubMed: 37624911
DOI: 10.1182/blood.2023019884 -
Amyloid : the International Journal of... Dec 2023In ATTR amyloidosis, transthyretin (TTR) protein is secreted from the liver and deposited as toxic aggregates at downstream target tissues. Despite recent advancements...
BACKGROUND
In ATTR amyloidosis, transthyretin (TTR) protein is secreted from the liver and deposited as toxic aggregates at downstream target tissues. Despite recent advancements in treatments for ATTR amyloidosis, the mechanisms underlying misfolded TTR-mediated cellular damage remain elusive.
METHODS
In an effort to define early events of TTR-associated stress, we exposed neuronal (SH-SY5Y) and cardiac (AC16) cells to wild-type and destabilized TTR variants (TTR (p.V142I) and TTR (p.L70P)) and performed transcriptional (RNAseq) and epigenetic (ATACseq) profiling. We subsequently compared TTR-responsive signatures to cells exposed to destabilized antibody light chain protein associated with AL amyloidosis as well as ER stressors (thapsigargin, heat shock).
RESULTS
In doing so, we observed overlapping, yet distinct cell type- and amyloidogenic protein-specific signatures, suggesting unique responses to each amyloidogenic variant. Moreover, we identified chromatin level changes in AC16 cells exposed to mutant TTR that resolved upon pre-incubation with kinetic stabilizer tafamidis.
CONCLUSIONS
Collectively, these data provide insight into the mechanisms underlying destabilized protein-mediated cellular damage and provide a robust resource representing cellular responses to aggregation-prone proteins and ER stress.
Topics: Humans; Amyloid Neuropathies, Familial; Amyloidogenic Proteins; Amyloidosis; Neuroblastoma; Neurons; Prealbumin
PubMed: 37439769
DOI: 10.1080/13506129.2023.2224494 -
Circulation Apr 2024The extent of myocardial bone tracer uptake with technetium pyrophosphate, hydroxymethylene diphosphonate, and 3,3-diphosphono-1,2-propanodicarboxylate in transthyretin...
BACKGROUND
The extent of myocardial bone tracer uptake with technetium pyrophosphate, hydroxymethylene diphosphonate, and 3,3-diphosphono-1,2-propanodicarboxylate in transthyretin amyloid cardiomyopathy (ATTR-CM) might reflect cardiac amyloid burden and be associated with outcome.
METHODS
Consecutive patients with ATTR-CM who underwent diagnostic bone tracer scintigraphy with acquisition of whole-body planar and cardiac single-photon emission computed tomography (SPECT) images from the National Amyloidosis Centre and 4 Italian centers were included. Cardiac uptake was defined according to the Perugini classification: 0=absent cardiac uptake; 1=mild uptake less than bone; 2=moderate uptake equal to bone; and 3=high uptake greater than bone. Extent of right ventricular (RV) uptake was defined as focal (basal segment of the RV free wall only) or diffuse (extending beyond basal segment) on the basis of SPECT imaging. The primary outcome was all-cause mortality.
RESULTS
Among 1422 patients with ATTR-CM, RV uptake accompanying left ventricular uptake was identified by SPECT imaging in 100% of cases at diagnosis. Median follow-up in the whole cohort was 34 months (interquartile range, 21 to 50 months), and 494 patients died. By Kaplan-Meier analysis, diffuse RV uptake on SPECT imaging (n=936) was associated with higher all-cause mortality compared with focal (n=486) RV uptake (77.9% versus 22.1%; <0.001), whereas Perugini grade was not associated with survival (=0.27 in grade 2 versus grade 3). On multivariable analysis, after adjustment for age at diagnosis (hazard ratio [HR], 1.03 [95% CI, 1.02-1.04]; <0.001), presence of the p.(V142I) variant (HR, 1.42 [95% CI, 1.20-1.81]; =0.004), National Amyloidosis Centre stage (each category, <0.001), stroke volume index (HR, 0.99 [95% CI, 0.97-0.99]; =0.043), E/e' (HR, 1.02 [95% CI, 1.007-1.03]; =0.004), right atrial area index (HR, 1.05 [95% CI, 1.02-1.08]; =0.001), and left ventricular global longitudinal strain (HR, 1.06 [95% CI, 1.03-1.09]; <0.001), diffuse RV uptake on SPECT imaging (HR, 1.60 [95% CI, 1.26-2.04]; <0.001) remained an independent predictor of all-cause mortality. The prognostic value of diffuse RV uptake was maintained across each National Amyloidosis Centre stage and in both wild-type and hereditary ATTR-CM (<0.001 and =0.02, respectively).
CONCLUSIONS
Diffuse RV uptake of bone tracer on SPECT imaging is associated with poor outcomes in patients with ATTR-CM and is an independent prognostic marker at diagnosis.
Topics: Humans; Cardiomyopathies; Prealbumin; Prognosis; Tomography, Emission-Computed, Single-Photon
PubMed: 38328945
DOI: 10.1161/CIRCULATIONAHA.123.066524 -
Journal of the American Heart... Aug 2023Background Transthyretin cardiac amyloidosis (ATTR-CM), found in 6% to 15% of cohorts with heart failure with preserved ejection fraction, has long been considered a... (Comparative Study)
Comparative Study
Background Transthyretin cardiac amyloidosis (ATTR-CM), found in 6% to 15% of cohorts with heart failure with preserved ejection fraction, has long been considered a rare disease with poor prognosis. New treatments have made it one of the few directly treatable causes of heart failure. This study sought to determine whether patients with ATTR-CM, particularly those treated with tafamidis, have comparable survival to an unselected cohort with heart failure with preserved ejection fraction. Methods and Results We compared the clinical characteristics and outcomes between a single-center cohort of patients with ATTR-CM (n=114) and patients with heart failure with preserved ejection fraction enrolled in the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) trial (n=1761, excluding Russia and Georgia). The primary outcome was a composite of all-cause death, heart failure hospitalization, myocardial infarction, and stroke. Subgroup analysis of patients with ATTR-CM treated with tafamidis was also performed. Patients with ATTR-CM had higher rates of the primary composite outcome compared with patients enrolled in the TOPCAT trial (hazard ratio [HR], 1.44 [95% CI, 1.09-1.91]; =0.01), with similar rates of all-cause death (HR, 1.43 [95% CI, 0.99-2.06]; =0.06) but higher rates of heart failure hospitalizations (HR, 1.62 [95% CI, 1.15-2.28]; <0.01). Compared with patients enrolled in TOPCAT, patients with ATTR-CM treated with tafamidis had similar rates of the primary composite outcome (HR, 1.30 [95% CI, 0.86-1.96]; =0.21) and all-cause death (HR, 1.10 [95% CI, 0.57-2.14]; =0.78) but higher rates of heart failure hospitalizations (HR, 1.96 [95% CI, 1.27-3.02]; <0.01). Conclusions Patients with ATTR-CM treated with tafamidis have similar rates of all-cause death compared with patients with heart failure with preserved ejection fraction, with higher rates of heart failure hospitalizations.
Topics: Humans; Amyloidosis; Cardiomyopathies; Heart Failure; Prealbumin; Spironolactone; Stroke Volume; Treatment Outcome
PubMed: 37522238
DOI: 10.1161/JAHA.123.029705 -
European Heart Journal. Cardiovascular... Jul 2023Tafamidis treatment positively affects left ventricular (LV) structure and function and improves outcomes in patients with transthyretin amyloid cardiomyopathy...
AIMS
Tafamidis treatment positively affects left ventricular (LV) structure and function and improves outcomes in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). We aimed to investigate the relationship between treatment response and cardiac amyloid burden identified by serial quantitative 99mTc-DPD SPECT/CT. We furthermore aimed to identify nuclear imaging biomarkers that could be used to quantify and monitor response to tafamidis therapy.
METHODS AND RESULTS
Forty wild-type ATTR-CM patients who underwent 99mTc-DPD scintigraphy and SPECT/CT imaging at baseline and after treatment with tafamidis 61 mg once daily [median, 9.0 months (interquartile range 7.0-10.0)] were divided into two cohorts based on the median (-32.3%) of the longitudinal percent change in standardized uptake value (SUV) retention index. ATTR-CM patients with a reduction greater than or equal to the median (n = 20) had a significant decrease in SUV retention index (P < 0.001) at follow-up, which translated into significant benefits in serum N-terminal prohormone of brain natriuretic peptide levels (P = 0.006), left atrial volume index (P = 0.038), as well as LV [LV global longitudinal strain: P = 0.028, LV ejection fraction (EF): P = 0.027, LV cardiac index (CI): P = 0.034] and right ventricular (RV) [RVEF: P = 0.025, RVCI: P = 0.048] functions compared with patients with a decrease less than the median (n = 20).
CONCLUSION
Treatment with tafamidis in ATTR-CM patients results in a significant reduction in SUV retention index, associated with significant benefits for LV and RV function and cardiac biomarkers. Serial quantitative 99mTc-DPD SPECT/CT imaging with SUV may be a valid tool to quantify and monitor response to tafamidis treatment in affected patients.
TRANSLATIONAL PERSPECTIVE
99mTc-DPD SPECT/CT imaging with determination of SUV retention index as part of a routine annual examination can provide evidence of treatment response in ATTR-CM patients receiving disease-modifying therapy. Further long-term studies with 99mTc-DPD SPECT/CT imaging may help to evaluate the relationship between tafamidis-induced reduction in SUV retention index and outcome in patients with ATTR-CM and will demonstrate whether highly disease-specific 99mTc-DPD SPECT/CT imaging is more sensitive than routine diagnostic monitoring.
Topics: Humans; Prealbumin; Amyloidosis; Single Photon Emission Computed Tomography Computed Tomography; Cardiomyopathies; Amyloid Neuropathies, Familial
PubMed: 36881774
DOI: 10.1093/ehjci/jead030