tafamidis and Amyloidosis

Cardiac amyloidosis is an underrecognized cause of heart failure. We review clinical clues to the diagnoses, a rational approach to testing, and current and emerging therapies.. Advances in the diagnosis of amyloid cardiomyopathy include (1) use of

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Benzoxazoles; Cardiomyopathies; Heart Failure; Humans; Immunoglobulin Light-chain Amyloidosis

Often considered a rare disease, cardiac amyloidosis is increasingly recognized by practicing clinicians. The increased rate of diagnosis is in part due the aging of the population and increasing incidence and prevalence of cardiac amyloidosis with advancing age, as well as the advent of noninvasive methods using nuclear scintigraphy to diagnose transthyretin cardiac amyloidosis due to either variant or wild type transthyretin without a biopsy. Perhaps the most important driver of the increased awareness is the elucidation of the biologic mechanisms underlying the pathogenesis of cardiac amyloidosis which have led to the development of several effective therapies with differing mechanisms of actions. In this review, the mechanisms underlying the pathogenesis of cardiac amyloidosis due to light chain (AL) or transthyretin (ATTR) amyloidosis are delineated as well as the rapidly evolving therapeutic landscape that has emerged from a better pathophysiologic understanding of disease development.

Topics: Aging; Alkylating Agents; Amyloid; Amyloid Neuropathies, Familial; Amyloidosis; Antibodies, Monoclonal; Benzoates; Benzoxazoles; Bridged Bicyclo Compounds, Heterocyclic; Cardiomyopathies; Catechol O-Methyltransferase Inhibitors; Heart Transplantation; Humans; Immunomodulating Agents; Oligonucleotides; Proteasome Inhibitors; Protein Folding; Pyrazoles; RNA, Small Interfering; Stem Cell Transplantation; Sulfonamides; Tolcapone

Cardiac amyloidosis (CA) is an infiltrative and restrictive cardiomyopathy that leads to heart failure, reduced quality of life, and death. The disease has two main subtypes, transthyretin cardiac amyloidosis (ATTR-CA) and immunoglobulin light chain cardiac amyloidosis (AL-CA), characterized by the nature of the infiltrating protein. ATTR-CA is further subdivided into wild-type (ATTRwt-CA) and variant (ATTRv-CA) based on the presence or absence of a mutation in the transthyretin gene. CA is significantly underdiagnosed and increasingly recognized as a cause of heart failure with preserved ejection fraction. Advances in diagnosis that employ nuclear scintigraphy to diagnose ATTR-CA without a biopsy and the emergence of effective treatments, including transthyretin stabilizers and silencers, have changed the landscape of this field and render early and accurate diagnosis critical. This review summarizes the epidemiology, pathophysiology, diagnosis, prognosis, and management of CA with an emphasis on the significance of recent developments and suggested future directions.

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Arrhythmias, Cardiac; Benzoates; Benzoxazoles; Biopsy; Cardiac Pacing, Artificial; Cardiomyopathies; Diflunisal; Disease Progression; Early Diagnosis; Early Medical Intervention; Echocardiography; Electrocardiography; Heart Failure; Humans; Immunoglobulin Light-chain Amyloidosis; Immunologic Factors; Magnetic Resonance Imaging; Oligonucleotides; Prealbumin; Prognosis; Proteasome Inhibitors; Pyrazoles; Radionuclide Imaging; RNA, Small Interfering

Systemic amyloid diseases are characterized by the deposition of an amyloidogenic protein as toxic oligomers and amyloid fibrils on tissues distal from the site of protein synthesis. Traditionally, these diseases have been viewed as disorders of peripheral target tissues where aggregates are deposited, and toxicity is observed. However, recent evidence highlights an important role for endoplasmic reticulum (ER) proteostasis pathways within tissues synthesizing and secreting amyloidogenic proteins, such as the liver, in the pathogenesis of these disorders. Here, we describe the pathologic implications of ER proteostasis and its regulation on the toxic extracellular aggregation of amyloidogenic proteins implicated in systemic amyloid disease pathogenesis. Furthermore, we discuss the therapeutic potential for targeting ER proteostasis to reduce the secretion and toxic aggregation of amyloidogenic proteins to mitigate peripheral amyloid-associated toxicity involved in the onset and progression of systemic amyloid diseases.

Topics: Amyloid; Amyloidogenic Proteins; Amyloidosis; Animals; Benzoxazoles; Drug Development; Endoplasmic Reticulum; Endoplasmic Reticulum Stress; Humans; Prealbumin; Proteostasis; Unfolded Protein Response

Hereditary transthyretin (TTR)-related amyloidosis is caused by mutations in the TTR gene. The mutations destabilize the tetramer and/or monomer of TTR, and thus the stabilization of TTR is a key strategy for the treatment of TTR-related amyloidosis. In this review, we summarized the natural products and synthetic compounds that have been shown to inhibit the amyloidogenesis of TTR. The stabilizers and/or the amyloid fibril disrupters isolated from natural sources may become lead compounds for the treatment of TTR-related amyloidosis.

Topics: Amyloid; Amyloidosis; Anti-Inflammatory Agents, Non-Steroidal; Benzoxazoles; Biological Products; Diflunisal; Humans; Mutation; Prealbumin

Tafamidis reduced all-cause mortality and cardiovascular-related hospitalizations and minimized patient-reported health status deterioration at 30 months in patients with transthyretin (ATTR) amyloidosis. However, the clinical significance of health status changes remains unclear, particularly in patients with New York Heart Association (NYHA) class III symptoms who experienced more cardiovascular-related hospitalizations than those with NYHA class I-II symptoms.. To evaluate the health status of patients taking tafamidis with baseline NYHA class III symptoms.. This randomized clinical trial post hoc analysis evaluated data for patients with transthyretin (ATTR) cardiac amyloidosis and NYHA class I-III symptoms at baseline who were enrolled in ATTR-ACT, a placebo-controlled study of tafamidis held at 48 sites in 13 countries.. Tafamidis meglumine, 80 mg or 20 mg (pooled cohort), vs placebo.. Established thresholds for clinical benefit on the Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) were used to define response groups (very large decline to very large improvement); the proportion of patients in each group was calculated within each baseline NYHA class.. Among 441 patients (264 tafamidis, 177 placebo), the mean (SD) age was 74.3 (7.0) years; 398 (90%) were male and 43 (10%) were female. Mean (SD) baseline KCCQ-OS scores were 67.3 (21.4) in the tafamidis group and 65.9 (21.7) in the placebo group (range: 0-100, with 100 indicating the best health). There was a significant shift toward better KCCQ-OS scores in patients receiving tafamidis (odds ratio for 10-point improvement 2.4; 95% CI, 1.6-3.4; P < .001). More patients taking tafamidis were alive and not worse at all time points (37% vs 15% at month 30). These findings were similar in patients with NYHA class III symptoms. In patients with NYHA class III symptoms alive at 30 months, improvements in health status were more common (35% vs 10%) and declines were less common (38% vs 57%) with tafamidis vs placebo.. In ATTR-ACT, although patients with baseline NYHA class III symptoms had worse overall outcomes, treatment with tafamidis yielded better health status compared with placebo.. ClinicalTrials.gov Identifier: NCT01994889.

Topics: Aged; Amyloidosis; Benzoxazoles; Female; Health Status; Humans; Male; Prealbumin

In the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), tafamidis significantly reduced mortality and cardiovascular (CV)-related hospitalizations compared with placebo in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). This analysis aimed to assess the causes of CV-related death and hospitalization in ATTR-ACT to provide further insight into the progression of ATTR-CM and efficacy of tafamidis. ATTR-ACT was an international, double-blind, placebo-controlled, and randomized study. Patients with hereditary or wild-type ATTR-CM were randomized to tafamidis (n = 264) or placebo (n = 177) for 30 months. The independent Endpoint Adjudication Committee determined whether certain investigator-reported events met the definition of disease-related efficacy endpoints using predefined criteria. Cause-specific reasons for CV-related deaths (heart failure [HF], arrhythmia, myocardial infarction, sudden death, stroke, and other CV causes) and hospitalizations (HF, arrhythmia, myocardial infarction, transient ischemic attack/stroke, and other CV causes) were assessed. Total CV-related deaths was 53 (20.1%) with tafamidis and 50 (28.2%) with placebo, with HF (15.5% tafamidis, 22.6% placebo), followed by sudden death (2.7% tafamidis, 5.1% placebo), the most common causes. The number of patients with a CV-related hospitalization was 138 (52.3%) with tafamidis and 107 (60.5%) with placebo; with HF the most common cause (43.2% tafamidis, 50.3% placebo). All predefined causes of CV-related death or hospitalization were less frequent with tafamidis than placebo. In conclusion, these data provide further insight into CV disease progression in patients with ATTR-CM, with HF the most common adjudicated cause of CV-related hospitalization or death in ATTR-ACT. Clinical trial registration ClinicalTrials.gov: NCT01994889.

Topics: Aged; Amyloid Neuropathies, Familial; Amyloidosis; Arrhythmias, Cardiac; Benzoxazoles; Cardiomyopathies; Cardiovascular Diseases; Cause of Death; Death, Sudden, Cardiac; Double-Blind Method; Female; Heart Failure; Hospitalization; Humans; Ischemic Attack, Transient; Male; Myocardial Infarction; Prealbumin; Proportional Hazards Models; Stroke

Emerging evidence suggests that several factors can impact disease progression in transthyretin amyloid polyneuropathy (ATTR-PN). The present analysis used longitudinal data from Val30Met patients participating in the tafamidis (selective TTR stabilizer) clinical development program to evaluate the impact of baseline neurologic severity on disease progression in ATTR-PN.. A linear mixed-effects model for repeated measures (MMRM) was constructed using tafamidis and placebo data from the intent-to-treat Val30Met population of the original registration study as well as tafamidis data from the two consecutive open-label extension studies. The second extension study is ongoing, but a prospectively-planned interim analysis involving a cleaned and locked database was conducted (cut-off: December 31, 2014). Val30Met patients are presented by treatment groups as those who received tafamidis during the registration and open-label studies (T-T group), or who received placebo during the registration study and were switched to tafamidis in the open-label studies (P-T group). Neurologic functioning was assessed at baseline and subsequent visits using the Neuropathy Impairment Score-Lower Limbs (NIS-LL). The analysis focused on the disease trajectory over the first 18 months of treatment.. The T-T (n = 64) and P-T (n = 61) cohorts were predominantly Caucasian and presented with early-stage neurologic disease (mean [standard deviation] baseline NIS-LL values were 8.4 [11.4] and 11.4 [13.5], respectively). The MMRM analysis demonstrated that baseline severity is an independent significant predictor of disease progression in addition to the treatment effect: patients with a lower baseline NIS-LL showed less progression than those with a higher baseline NIS-LL (p < 0.0001). Neurologic progression in the T-T group was less than in the P-T group across all levels of baseline NIS-LL (p = 0.0088), and the degree of separation increased over the 18-month period. Similar results were seen with the NIS-LL muscle weakness subscale.. This analysis of patients with Val30Met ATTR-PN demonstrates that neurologic disease progression strongly depends on baseline neurologic severity and illustrates the disease-modifying effect of tafamidis relative to placebo across a range of baseline levels of neurologic severity and treatment durations. These data also underscore the benefit of early diagnosis and treatment with tafamidis in delaying disease progression in ATTR-PN.. NCT00409175 , NCT00791492 and NCT00925002 registered 08 December 2006, 14 November 2008 (retrospectively registered), and 19 June 2009, respectively.

Topics: Adult; Amyloid Neuropathies; Amyloidosis; Benzoxazoles; Disease Progression; Double-Blind Method; Female; Humans; Male; Middle Aged; Prealbumin; Prospective Studies

The impact of tafamidis on myocardial strain in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) have been barely investigated. We aimed to determine tafamidis-induced changes using serial speckle tracking echocardiography and to identify imaging parameters for specific therapy monitoring.. ATTR-CM patients underwent serial TTE with two-dimensional (2 D) speckle tracking imaging. Patients receiving tafamidis free acid 61 mg (. Treatment with tafamidis free acid 61 mg in ATTR-CM patients delays the deterioration of LA and LV longitudinal function, resulting in significant clinical benefits compared with natural history. Serial TTE with 2 D speckle tracking imaging may be appropriate for disease-specific therapy monitoring.

Topics: Amyloidosis; Cardiomyopathies; Echocardiography; Humans; Myocardium; Prealbumin; Ventricular Function, Left

Topics: Amyloidosis; Cardiomyopathies; Humans; Prealbumin; Radionuclide Imaging; Tomography, X-Ray Computed

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Cardiomyopathies; Diphosphates; Heart Failure; Humans; Prealbumin; Radionuclide Imaging; Radiopharmaceuticals; Technetium

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Cardiomyopathies; Diphosphates; Humans; Prealbumin; Predictive Value of Tests

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.. 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).. 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.. 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: Amyloid Neuropathies, Familial; Amyloidosis; Cardiomyopathies; Humans; Prealbumin; Single Photon Emission Computed Tomography Computed Tomography

Tafamidis has been used for treatment of transthyretin cardiac amyloidosis (ATTR-CA). However, Tc-99 m pyrophosphate (PYP) cardiac scan for follow-up after tafamidis therapy has not been reported.. From May 2017 to March 2022, five patients with or without tafamidis therapy had received two Tc-99 m PYP cardiac scans. Tc-99 m PYP cardiac scan was performed with planar image and single photon emission computed tomography/computed tomography (SPECT/CT) 3 h after administration of Tc-99 m PYP. Perugini grading system was applied to determine positive or negative result of the scan. Heart to contralateral lung (H/CL) ratio as well as the difference of H/CL ratio between first and second Tc-99 m PYP cardiac scans (ΔH/CL ratio) was calculated.. In the five patients participated in this study, three received tafamidis therapy and H/CL ratio was significantly decreased (p = 0.02) after tafamidis therapy. Besides, the ΔH/CL ratio was larger in patients with tafamidis therapy than that in those without tafamidis therapy, albeit not reaching statistical significance (p = 0.2).. A decrease in H/CL ratio was found after tafamidis therapy in patients with ATTR-CA, albeit the magnitude of changes in the H/CL ratio (ΔH/CL ratio) was not significantly different from that of patients without tafamidis therapy. Future study with larger population might be required to further clarify the effect of tafamidis therapy on myocardial uptake of Tc-99 m PYP.. No clinical trial was conducted in our retrospective study.

Topics: Amyloidosis; Cardiomyopathies; Diphosphates; Follow-Up Studies; Humans; Prealbumin; Retrospective Studies; Technetium Tc 99m Pyrophosphate

Tafamidis improves prognosis in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). However, real-world data on the therapeutic effect of tafamidis are lacking. This study aimed to evaluate the clinical course, outcomes, and effectivity monitoring of the therapeutic effect of tafamidis in patients with ATTR-CM.. This is a single-centre, retrospective observational study. We evaluated the clinical characteristics and outcomes in 125 consecutive patients with wild-type ATTR-CM (ATTRwt-CM) treated with tafamidis (treatment group) and 55 untreated patients (treatment-naïve group). We monitored the therapeutic effect of tafamidis for 12 months by evaluating serial cardiac biomarker and imaging findings. The treatment group had significantly more favourable outcome in all-cause mortality and hospitalization due to heart failure than the treatment-naïve group in both the entire cohort (P < 0.01) and the propensity score-matched cohort (P < 0.05). Kaplan-Meier survival curves showed that tafamidis treatment significantly reduced all-cause mortality (P = 0.03, log-rank test), with the curves diverging after approximately 18 months of treatment in the propensity score-matched cohort. On inverse probability of treatment weighting analysis, tafamidis treatment showed a reduced all-cause mortality [hazard ratio (HR), 0.31; 95% confidence interval (CI), 0.11-0.93; P = 0.04]. High-sensitivity cardiac troponin T (hs-cTnT) > 0.05 ng/mL, B-type natriuretic peptide (BNP) > 250 pg/mL, and estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m. The prognosis of patients with ATTRwt-CM treated with tafamidis was more favourable than that of untreated patients. Patient stratification combined with biomarkers (hs-cTnT, BNP, and eGFR) predicted clinical outcomes. hs-cTnT may be a useful biomarker for evaluating the therapeutic effect of tafamidis.

Topics: Amyloidosis; Biomarkers; Cardiomyopathies; Heart Failure; Humans; Prealbumin

Topics: Amyloidosis; Cardiomyopathies; Humans; Prealbumin; Single Photon Emission Computed Tomography Computed Tomography

Transthyretin cardiac cardiomyopathy (ATTR-CM) is a rare but life-threatening disease. Tafamidis is an effective treatment for patients with ATTR-CM, however its long-term effects on cardiac remodeling and cardiac amyloid deposition are unknown. This study aimed to used cardiac magnetic resonance (CMR) to investigate the effects of tafamidis on patients with hereditary A97S ATTR-CM.. We retrospectively analyzed a prospective cohort of ATTR-CM patients, including 14 with hereditary A97S ATTR-CM and 17 healthy controls with baseline CMR data. All ATTR-CM patients received tafamidis treatment and received CMR with extracellular volume (ECV) at baseline and after 1 year of follow-up.. Baseline N-terminal pro-B-type natriuretic peptide, left ventricular (LV) mass, LV ejection fraction, global radial, circumferential and longitudinal strain, T1 mapping and ECV were significantly worse in the patients with ATTR-CM compared with the healthy controls. After 1 year of tafamidis treatment, ECV decreased from 51.5 ± 8.9% to 49.0 ± 9.4% (P = 0.041), however there were no significant changes in LV mass, LV ejection fraction, global radial strain, global circumferential strain, global longitudinal strain and T1 mapping.. After a one-year treatment period, tafamidis exhibited subtle but statistically significant reductions in ECV, potentially indicating a decrease in amyloid deposition among patients diagnosed with hereditary A97S ATTR-CM.

Topics: Amyloidosis; Cardiomyopathies; Follow-Up Studies; Humans; Prealbumin; Prospective Studies; Retrospective Studies

Tafamidis improves outcomes in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). However, it is not yet known whether tafamidis affects cardiac amyloid deposition and structural changes in the myocardium. We aimed to determine disease-modifying effects on myocardial amyloid progression and to identify imaging parameters that could be applied for specific therapy monitoring.. ATTR-CM patients underwent serial cardiac magnetic resonance (CMR) imaging using T1 mapping techniques to derive extracellular volume (ECV). Patients receiving tafamidis 61 mg (n = 35) or 20 mg (n = 15) once daily showed stable measurements at follow-up (FU) {61 mg: 9.0 [interquartile range (IQR) 7.0-11.0] months, 20 mg: 11.0 (IQR 8.0-18.0) months} in left ventricular (LV) ejection fraction (LVEF; 61 mg: 47.6% vs. 47.5%, P = 0.935; 20 mg: 52.4% vs. 52.1%, P = 0.930), LV mass index (LVMI; 61 mg: 110.2 vs. 106.2 g/m2, P = 0.304; 20 mg: 114.5 vs. 115.4 g/m2, P = 0.900), and ECV (61 mg: 47.5% vs. 47.7%, P = 0.861; 20 mg: 56.7% vs. 57.5%, P = 0.759), whereas treatment-naïve ATTR-CM patients (n = 19) had clear signs of disease progression at the end of the observation period [12.0 (IQR 10.0-21.0) months; LVEF: 53.3% vs. 45.7%, P = 0.031; LVMI: 98.9 vs. 106.9 g/m2, P = 0.027; ECV: 49.3% vs. 54.6%, P = 0.023]. Between-group comparison at FU revealed positive effects in tafamidis 61 mg-treated compared to treatment-naïve patients (LVEF: P = 0.035, LVMI: P = 0.036, ECV: P = 0.030), while those treated with 20 mg showed no difference in the above LV measurements when compared with treatment-naïve (P = 0.120, P = 0.287, P = 0.158). However, both treatment groups showed clinically beneficial effects compared to the natural course [61 mg, 6-min walk distance (6-MWD): P = 0.005, N-terminal prohormone of brain natriuretic peptide (NT-proBNP): P = 0.002; 20 mg, 6-MWD: P = 0.023, NT-proBNP: P = 0.003].. Tafamidis delays myocardial amyloid progression in ATTR-CM patients, resulting in structural, functional, and clinical benefits compared to the natural course. Serial CMR including measurement of ECV may be appropriate for disease-specific therapy monitoring.

Topics: Amyloidosis; Benzoxazoles; Cardiomyopathies; Heart Ventricles; Humans; Prealbumin; Time-to-Treatment

Present study describes a high-performance liquid chromatography method for the determination of the potent kinetic stabilizer-Tafamidis in human plasma. It was approved for medical use in European Union in 2011. Ultra violet (UV) detection mode and isocratic elution of the mobile phase were set and made the analytical procedure fast and widely applicable. Chromatographic determination was performed on a Purospher® RP-18 column. The mobile phase consisted of 0.1% trifluoroacetic acid in water and acetonitrile in the ratio 42:58 v/v and the flow rate was 1.0 ml/min. All analyses were carried at a room temperature and the detector was set at 280 nm. Calibration curve over a range of 1.00-10.00 μM was constructed for the purposes of linearity method validation. The specificity and effectiveness of the developed method made it suitable for observation of patients' plasma Tafamidis concentration with time and drug therapy monitoring.

Topics: Amyloidosis; Benzoxazoles; Chromatography, High Pressure Liquid; Humans; Mutation

In patients with transthyretin amyloid cardiomyopathy (ATTR-CM), the effect of tafamidis on myocardial function using serial speckle tracking echocardiography has not been reported. The purpose of this study was to describe the natural history of myocardial function in untreated ATTR-CM and determine the effect of tafamidis on myocardial functional parameters over 12 months of treatment.. A total of 45 subjects with ATTR-CM were retrospectively studied: 23 treated with tafamidis and 22 untreated. Two-dimensional speckle tracking echocardiography was analysed at baseline and 1 year. Serial longitudinal, circumferential, and radial strain, twist, torsion, and myocardial work were measured. Over 1 year, absolute global longitudinal strain (GLS) deteriorated more in the untreated group by a median of 1.1% [inter-quartile range (IQR) 0.95] compared with 0.3% (IQR 1) in the tafamidis group (P = 0.02). Myocardial work index and efficiency also deteriorated to a greater degree: 142.5 mmHg% (IQR 197) and 4% (IQR 8), respectively, in the untreated group compared with 61.5 mmHg% (IQR 210) and 1% (IQR 7) in the tafamidis group (P = 0.04). There were no significant between group differences in left ventricular ejection fraction (LVEF), tissue Doppler velocities, circumferential or radial strain, LV twist or torsion at 1 year. The stabilization effect of tafamidis on myocardial function at 1 year did not differ according to baseline GLS, LVEF, or National Amyloidosis Centre disease stage.. In ATTR-CM, tafamidis resulted in a lesser deterioration in GLS, myocardial work index, and efficiency over a 12-month period compared with a cohort not treated with tafamidis.

Topics: Amyloidosis; Benzoxazoles; Humans; Prealbumin; Retrospective Studies; Stroke Volume; Ventricular Function, Left

Topics: Amyloidosis; Benzoxazoles; Biopsy; Humans; Ligaments

Cardiac amyloidosis usually presents with diastolic dysfunction, but sometimes systolic dysfunction develops, particularly at its advanced stage. However, the therapeutic strategy for patients with cardiac amyloidosis and systolic dysfunction remains unknown. We report a 77-year-old man who was diagnosed with wild-type cardiac amyloidosis and systolic dysfunction with a left ventricular ejection fraction of 27%. Following 6-month medical therapy of tafamidis 80 mg and neurohormonal blockers (carvedilol 5.0 mg, enalapril 2.5 mg, and spironolactone 25 mg), the left ventricular ejection fraction improved to 55%. Tafamidis-incorporated neurohormonal blocker therapy might be a promising strategy to facilitate cardiac reverse remodeling in patients with cardiac amyloidosis and systolic dysfunction.

Topics: Aged; Amyloidosis; Benzoxazoles; Cardiomyopathies; Carvedilol; Humans; Male; Stroke Volume; Ventricular Function, Left

In this update, we focus on selected topics of high clinical relevance for health care providers who treat patients with heart failure (HF), on the basis of clinical trials published after 2017. Our objective was to review the evidence, and provide recommendations and practical tips regarding the management of candidates for the following HF therapies: (1) transcatheter mitral valve repair in HF with reduced ejection fraction; (2) a novel treatment for transthyretin amyloidosis or transthyretin cardiac amyloidosis; (3) angiotensin receptor-neprilysin inhibition in patients with HF and preserved ejection fraction (HFpEF); and (4) sodium glucose cotransport inhibitors for the prevention and treatment of HF in patients with and without type 2 diabetes. We emphasize the roles of optimal guideline-directed medical therapy and of multidisciplinary teams when considering transcatheter mitral valve repair, to ensure excellent evaluation and care of those patients. In the presence of suggestive clinical indices, health care providers should consider the possibility of cardiac amyloidosis and proceed with proper investigation. Tafamidis is the first agent shown in a prospective study to alter outcomes in patients with transthyretin cardiac amyloidosis. Patient subgroups with HFpEF might benefit from use of sacubitril/valsartan, however, further data are needed to clarify the effect of this therapy in patients with HFpEF. Sodium glucose cotransport inhibitors reduce the risk of incident HF, HF-related hospitalizations, and cardiovascular death in patients with type 2 diabetes and cardiovascular disease. A large clinical trial recently showed that dapagliflozin provides significant outcome benefits in well treated patients with HF with reduced ejection fraction (left ventricular ejection fraction ≤ 40%), with or without type 2 diabetes.

Topics: Amyloidosis; Angiotensin Receptor Antagonists; Benzoxazoles; Heart Diseases; Heart Failure; Humans; Mitral Valve Insufficiency; Neprilysin; Randomized Controlled Trials as Topic; Severity of Illness Index; Sodium-Glucose Transporter 2 Inhibitors; Stroke Volume

We have recently argued that, because microbes have pervasive - often vital - influences on our lives, and that therefore their roles must be taken into account in many of the decisions we face, society must become microbiology-literate, through the introduction of relevant microbiology topics in school curricula (Timmis et al. 2019. Environ Microbiol 21: 1513-1528). The current coronavirus pandemic is a stark example of why microbiology literacy is such a crucial enabler of informed policy decisions, particularly those involving preparedness of public-health systems for disease outbreaks and pandemics. However, a significant barrier to attaining widespread appreciation of microbial contributions to our well-being and that of the planet is the fact that microbes are seldom visible: most people are only peripherally aware of them, except when they fall ill with an infection. And it is disease, rather than all of the positive activities mediated by microbes, that colours public perception of 'germs' and endows them with their poor image. It is imperative to render microbes visible, to give them life and form for children (and adults), and to counter prevalent misconceptions, through exposure to imagination-capturing images of microbes and examples of their beneficial outputs, accompanied by a balanced narrative. This will engender automatic mental associations between everyday information inputs, as well as visual, olfactory and tactile experiences, on the one hand, and the responsible microbes/microbial communities, on the other hand. Such associations, in turn, will promote awareness of microbes and of the many positive and vital consequences of their actions, and facilitate and encourage incorporation of such consequences into relevant decision-making processes. While teaching microbiology topics in primary and secondary school is key to this objective, a strategic programme to expose children directly and personally to natural and managed microbial processes, and the results of their actions, through carefully planned class excursions to local venues, can be instrumental in bringing microbes to life for children and, collaterally, their families. In order to encourage the embedding of microbiology-centric class excursions in current curricula, we suggest and illustrate here some possibilities relating to the topics of food (a favourite pre-occupation of most children), agriculture (together with horticulture and aquaculture), health and medicine, the en

Topics: Adult; Amyloidosis; Benzoxazoles; Child; Humans; Prealbumin

Topics: Amyloidosis; Benzoxazoles; Cardiomyopathies; Humans; Japan; Prognosis; Treatment Outcome

Topics: Amyloidosis; Benzoxazoles; Cardiomyopathies; Humans; Prealbumin

Transthyretin (TTR) is a homotetrameric protein. Its dissociation into monomers leads to the formation of fibrils that underlie human amyloidogenic diseases. The binding of small molecules to the thyroxin-binding sites in TTR stabilizes the homotetramer and attenuates TTR amyloidosis. Herein, we report on boronic acid-substituted stilbenes that limit TTR amyloidosis in vitro. Assays of affinity for TTR and inhibition of its tendency to form fibrils were coupled with X-ray crystallographic analysis of nine TTR·ligand complexes. The ensuing structure-function data led to a symmetrical diboronic acid that forms a boronic ester reversibly with serine 117. This diboronic acid inhibits fibril formation by both wild-type TTR and a common disease-related variant, V30M TTR, as effectively as does tafamidis, a small-molecule drug used to treat TTR-related amyloidosis in the clinic. These findings establish a new modality for covalent inhibition of fibril formation and illuminate a path for future optimization.

Topics: Amyloidosis; Boronic Acids; Crystallography, X-Ray; Humans; Ligands; Models, Molecular; Point Mutation; Prealbumin; Protein Aggregates; Stilbenes

Amyloid formation of the human plasma protein transthyretin (TTR) is associated with several human disorders, including familial amyloidotic polyneuropathy (FAP) and senile systemic amyloidosis. Dissociation of TTR's native tetrameric assembly is the rate-limiting step in the conversion into amyloid, and this feature presents an avenue for intervention because binding of an appropriate ligand to the thyroxin hormone binding sites of TTR stabilizes the native tetrameric assembly and impairs conversion into amyloid. The desired features for an effective TTR stabilizer include high affinity for TTR, high selectivity in the presence of other proteins, no adverse side effects at the effective concentrations, and a long half-life in the body. In this study we show that the commonly used flame retardant tetrabromobisphenol A (TBBPA) efficiently stabilizes the tetrameric structure of TTR. The X-ray crystal structure shows TBBPA binding in the thyroxine binding pocket with bromines occupying two of the three halogen binding sites. Interestingly, TBBPA binds TTR with an extremely high selectivity in human plasma, and the effect is equal to the recently approved drug tafamidis and better than diflunisal, both of which have shown therapeutic effects against FAP. TBBPA consequently present an interesting scaffold for drug design. Its absorption, metabolism, and potential side-effects are discussed.

Topics: Amyloid; Amyloidosis; Benzoxazoles; Binding Sites; Cell Line, Tumor; Crystallography, X-Ray; Diflunisal; Drug Design; Excipients; Half-Life; Humans; Ligands; Polybrominated Biphenyls; Prealbumin; Protein Binding; Thyroxine

The transthyretin (TTR) amyloidoses are a group of degenerative diseases caused by TTR aggregation, requiring rate-limiting tetramer dissociation. Kinetic stabilization of TTR, by preferential binding of a drug to the native tetramer over the dissociative transition state, dramatically slows the progression of familial amyloid polyneuropathy. An established method for quantifying the kinetic stability of recombinant TTR tetramers in buffer is subunit exchange, in which tagged TTR homotetramers are added to untagged homotetramers at equal concentrations to measure the rate at which the subunits exchange. Herein, we report a subunit exchange method for quantifying the kinetic stability of endogenous TTR in human plasma. The subunit exchange reaction is initiated by the addition of a substoichiometric quantity of FLAG-tagged TTR homotetramers to endogenous TTR in plasma. Aliquots of the subunit exchange reaction, taken as a function of time, are then added to an excess of a fluorogenic small molecule, which immediately arrests further subunit exchange. After binding, the small molecule reacts with the TTR tetramers, rendering them fluorescent and detectable in human plasma after subsequent ion exchange chromatography. The ability to report on the extent of TTR kinetic stabilization resulting from treatment with oral tafamidis is important, especially for selection of the appropriate dose for patients carrying rare mutations. This method could also serve as a surrogate biomarker for the prediction of the clinical outcome. Subunit exchange was used to quantify the stabilization of WT TTR from senile systemic amyloidosis patients currently being treated with tafamidis (20 mg orally, once daily). TTR kinetic stability correlated with the tafamidis plasma concentration.

Topics: Amyloidosis; Animals; Benzoxazoles; Chromatography, Ion Exchange; Humans; Mice; Mice, Knockout; Prealbumin; Protein Binding; Protein Stability; Protein Structure, Secondary; Protein Subunits

The misassembly of soluble proteins into toxic aggregates, including amyloid fibrils, underlies a large number of human degenerative diseases. Cardiac amyloidoses, which are most commonly caused by aggregation of Ig light chains or transthyretin (TTR) in the cardiac interstitium and conducting system, represent an important and often underdiagnosed cause of heart failure. Two types of TTR-associated amyloid cardiomyopathies are clinically important. The Val122Ile (V122I) mutation, which alters the kinetic stability of TTR and affects 3% to 4% of African American subjects, can lead to development of familial amyloid cardiomyopathy. In addition, aggregation of WT TTR in individuals older than age 65 y causes senile systemic amyloidosis. TTR-mediated amyloid cardiomyopathies are chronic and progressive conditions that lead to arrhythmias, biventricular heart failure, and death. As no Food and Drug Administration-approved drugs are currently available for treatment of these diseases, the development of therapeutic agents that prevent TTR-mediated cardiotoxicity is desired. Here, we report the development of AG10, a potent and selective kinetic stabilizer of TTR. AG10 prevents dissociation of V122I-TTR in serum samples obtained from patients with familial amyloid cardiomyopathy. In contrast to other TTR stabilizers currently in clinical trials, AG10 stabilizes V122I- and WT-TTR equally well and also exceeds their efficacy to stabilize WT and mutant TTR in whole serum. Crystallographic studies of AG10 bound to V122I-TTR give valuable insights into how AG10 achieves such effective kinetic stabilization of TTR, which will also aid in designing better TTR stabilizers. The oral bioavailability of AG10, combined with additional desirable drug-like features, makes it a very promising candidate to treat TTR amyloid cardiomyopathy.

Topics: Amyloid; Amyloidosis; Animals; Area Under Curve; Benzoates; Benzoxazoles; Cardiomyopathies; Cell Line; Cell Line, Tumor; Cell Survival; Crystallography, X-Ray; Dose-Response Relationship, Drug; HeLa Cells; Humans; MCF-7 Cells; Mice; Mice, Inbred ICR; Models, Molecular; Molecular Structure; Mutation; Prealbumin; Protein Binding; Protein Stability; Protein Structure, Tertiary; Pyrazoles; Rats; Rats, Wistar

CHI's 17th International Tri-Conference on Molecular Medicine, held in San Francisco, included topics covering new developments in the field of medicinal chemistry. This conference report highlights selected presentations on fragment-based drug discovery, quantum mechanical energy decomposition for the analysis of SARs, medicinal chemistry strategies and the role of imaging in drug discovery. Investigational drugs discussed include MLN-4924 (Millennium Pharmaceuticals Inc), GDC-0449 (Chugai Pharmaceutical Co Ltd/Curis Inc/F Hoffmann-La Roche Ltd/Genentech Inc/NCI), RDEA-119 (Ardea Biosciences Inc/Bayer HealthCare AG) and tafamidis (Fx-1006A; FoldRx Pharmaceuticals Inc).

Topics: Alzheimer Disease; Amyloidosis; Anilides; Animals; Benzoxazoles; Chemistry, Pharmaceutical; Drug Discovery; Drug-Related Side Effects and Adverse Reactions; Enzyme Inhibitors; HSP90 Heat-Shock Proteins; Humans; Macrocyclic Compounds; Neoplasms; Pharmacokinetics; Positron-Emission Tomography; Pyridines; Quantum Theory; Receptors, Immunologic; Receptors, Prostaglandin; Structure-Activity Relationship