Amyloid Polyneuropathy Research Articles

Cardiac Amyloidosis: A Comprehensive Review of Pathophysiology, Diagnostic Approach, Applications of Artificial Intelligence, and Management Strategies.

Cardiac amyloidosis (CA) is a serious and often fatal condition caused by the accumulation of amyloid fibrils in the heart, leading to progressive heart failure. It involves the misfolding of normally soluble proteins into insoluble amyloid fibrils, with transthyretin and light-chain amyloidosis being the most common forms affecting the heart. Advances in diagnostics, especially cardiac magnetic resonance imaging and non-invasive techniques, have improved early detection and disease management. Artificial intelligence has emerged as a diagnostic tool for cardiac amyloidosis, improving accuracy and enabling earlier intervention through advanced imaging analysis and pattern recognition. Management strategies include volume control, specific pharmacotherapies like tafamidis, and addressing arrhythmias and advanced heart failure. However, further research is needed for novel therapeutic approaches, the long-term effectiveness of emerging treatments, and the optimization of artificial intelligence applications in clinical practice for better patient outcomes.The article aims to provide an overview of CA, outlining its pathophysiology, diagnostic advancements, the role of artificial intelligence, management strategies, and the need for further research.

Response to therapy with tafamidis 61 mg in patients with cardiac transthyretin amyloidosis: real-world experience since approval

Aims Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive disease that causes heart failure due to amyloid fibril deposition. Tafamidis was approved as the first causal treatment in 2020. We here report on real-world data in patients treated with tafamidis for at least 12 months according to the recently defined European Society for Cardiology (ESC) consensus criteria for disease progression. Methods and results Three hundred and eight wildtype and 31 hereditary ATTR-CM patients were prospectively enrolled after first diagnosis of ATTR-CM and initiation of tafamidis 61 mg once daily treatment. After 12 months, significant deterioration in Karnofsky Index, estimated glomerular filtration rate (eGFR), N-terminal brain natriuretic peptide (NT-proBNP), septum thickness and left ventricular ejection fraction (LVEF) could be observed, significant disease progression was only detected in 25 patients (9%) using ESC consensus criteria. Mean survival time was 37 months with no differences between responders and non-responders. NT-proBNP was the only independent predictor for poor therapy response (p = .008). Conclusions The majority of patients showed no significant disease progression according to the ESC consensus criteria after 12 months of therapy with tafamidis. However, at 12 months, treatment response based on the ESC consensus criteria was not associated with improved survival. Moreover, higher levels of NT-proBNP at diagnosis of ATTR-CM appears to predict poorer treatment response, confirming that timely initiation of therapy is advantageous.

Cardiac amyloidosis and aortic stenosis: what do we know?

Aortic valve stenosis and cardiac amyloidosis, particularly transthyretin-related, often coexist and share a common clinical and demographic profile. Several pathophysiological hypotheses have been proposed regarding the causes of this association, neither of which fully substantiated in practice. The key to detect the coexistence of cardiac amyloidosis and aortic valve stenosis lies in clinical suspicion. It is possible to hypothesize concurrent cardiac amyloidosis in patients with aortic valve stenosis with the aid of clinical, electrocardiographic, echocardiographic, and extracardiac "red flags". Subsequent non-invasive diagnostic steps are often sufficient to establish a definitive diagnosis. The early diagnosis of this condition is pivotal since the presence of dual pathology worsens patient's prognosis, especially without intervention. Available data on treatment show a better outcome in terms of survival and cardiovascular events in patients undergoing percutaneous correction of valvular heart disease rather than medical therapy alone, regardless of the presence of cardiac amyloidosis. Furthermore, it seems that cardiac amyloidosis does not impact survival after transcatheter aortic valve replacement, even if higher rates of rehospitalizations have been described. Indeed, percutaneous treatment of valvular heart disease is currently considered the primary therapeutic option. Subsequently a disease-modifying treatment for transthyretin amyloidosis may be considered in order to delay disease progression and improve outcomes, even if specific data are still lacking.

A mini-review of Vutrisiran and Eplontersen in hereditary transthyretin-mediated amyloidosis with polyneuropathy.

Hereditary transthyretin-mediated amyloidosis (ATTRv amyloidosis), known as Corino de Andrade disease, is a rare neurodegenerative disorder with a significant global impact characterized by the misfolding of transthyretin (TTR) protein leading to amyloid aggregation, ATTRv amyloidosis, especially with polyneuropathy, poses a considerable challenge in managing its rapid progression and debilitating effects. This mini-review focuses on the recent advancements in the treatment landscape for ATTRv amyloidosis with polyneuropathy, specifically the RNA interference therapeutic Vutrisiran and the ligand-conjugated antisense oligonucleotide Eplontersen. We aim to provide a comprehensive overview of the mechanisms, current evidence from clinical trials, and future directions for these novel therapeutic agents. Vutrisiran and Eplontersen have demonstrated significant clinical efficacy in improving neuropathic impairment, quality of life, and serum TTR levels in various trials. The distinct mechanistic approaches of these therapies, coupled with their acceptable safety profiles, offer promising avenues for addressing the complexities of ATTRv amyloidosis with polyneuropathy. The introduction of Vutrisiran and Eplontersen marks a pivotal moment in the quest for effective therapies against ATTRv amyloidosis with polyneuropathy. While clinical evidence is promising, ongoing research is crucial to deepen mechanistic understanding and address research gaps. Future perspectives include the potential expansion of therapeutic options and a more inclusive approach to cater to the diverse needs of individuals globally. This mini-review provides valuable insights into the evolving landscape of ATTRv amyloidosis management and sets the stage for further exploration in this challenging domain.

Impact of Tafamidis on Delaying Clinical, Functional, and Structural Cardiac Changes in Patients with Wild-Type Transthyretin Amyloid Cardiomyopathy.

Background: This study aimed to evaluate the effect of treatment with tafamidis on clinical, laboratory, functional, and structural cardiovascular imaging parameters at the 12-month follow-up timepoint in patients with wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) and to assess the response to treatment in terms of disease progression. Methods: Patients with ATTRwt-CM undergoing treatment with tafamidis for >12 months were included. The patients underwent a comprehensive evaluation (including echocardiography, cardiac magnetic resonance imaging, six-minute walking test, assessment of quality of life, and laboratory tests) at baseline and the 12-month follow-up timepoint. Disease progression was assessed using a set of tools proposed by an international panel of experts, evaluating three main domains (clinical, biochemical, and structural). Results: The study cohort consisted of 25 patients (mean age of 75.9 ± 6.1 years, with 92% males). At the 12-month follow-up timepoint, an improvement in quality of life calculated with the KCCQ overall score (64 ± 20 vs. 75 ± 20, p = 0.002) and a reduction in pulmonary artery pressure (34 ± 10 mmHg vs. 30 ± 5 mmHg, p-value = 0.008) and in native T1 time were observed (1162 ± 66 ms vs. 1116 ± 52 ms, p-value = 0.001). Clinical, biochemical, and structural disease progression was observed in 6 (24%), 13 (52%), and 7 (28%) patients, respectively. Overall disease progression was observed in two patients (8%). Conclusions: This study described the impact of tafamidis treatment on clinical, laboratory, and functional parameters. Disease progression, assessed using a multiparametric tool recommended by a recent position paper of experts, was observed in a minority of patients.

Mechanisms of Action of the US Food and Drug Administration-Approved Antisense Oligonucleotide Drugs.

Antisense oligonucleotides (ASOs) are single stranded nucleic acids that target RNA. The US Food and Drug Administration has approved ASOs for several diseases. ASOs utilize three principal modes of action (MOA). The first MOA is initiated by base-pairing between the ASO and its target mRNA, followed by RNase H-dependent mRNA degradation. The second MOA is triggered by ASOs that occlude splice acceptor sites in pre-mRNAs leading to skipping of a mutation-bearing exon. The third MOA involves ASOs that sterically hinder mRNA function, often inhibiting translation. ASOs contain a variety of modifications to the sugar-phosphate backbone and bases that stabilize the ASO or render them resistant to RNase activity. RNase H-dependent ASOs include inotersen and eplontersen (for hereditary transthyretin amyloidosis), fomiversen (for opportunistic cytomegalovirus infection), mipomersen (for familial hypercholesterolemia), and tofersen [for amyotrophic lateral sclerosis (ALS)]. Splice modulating ASOs include nursinersen (for spinal muscular atrophy) and eteplirsen, golodirsen, viltolarsen, and casimersen (all for the treatment of Duchenne muscular dystrophy). In addition, a designer ASO, milasen, was used to treat a single individual afflicted with Batten disease. Since ASO design relies principally upon knowledge of mRNA sequence, the bench to bedside pipeline for ASOs is expedient compared with protein-directed drugs.[Graphical abstract available.].

Amyloid Neuropathy: From Pathophysiology to Treatment in Light-Chain Amyloidosis and Hereditary Transthyretin Amyloidosis.

Amyloid neuropathy is caused by deposition of insoluble β-pleated amyloid sheets in the peripheral nervous system. It is most common in: (1) light-chain amyloidosis, a clonal non-proliferative plasma cell disorder in which fragments of immunoglobulin, light or heavy chain, deposit in tissues, and (2) hereditary transthyretin (ATTRv) amyloidosis, a disorder caused by autosomal dominant mutations in the TTR gene resulting in mutated protein that has a higher tendency to misfold. Amyloid fibrils deposit in the endoneurium of peripheral nerves, often extensive in the dorsal root ganglia and sympathetic ganglia, leading to atrophy of Schwann cells in proximity to amyloid fibrils and blood-nerve barrier disruption. Clinically, amyloid neuropathy is manifested as a length-dependent sensory predominant neuropathy associated with generalized autonomic failure. Small unmyelinated nerves are involved early and prominently in early-onset Val30Met ATTRv, whereas other ATTRv and light-chain amyloidosis often present with large- and small-fiber involvement. Nerve conduction studies, quantitative sudomotor axon testing, and intraepidermal nerve fiber density are useful tools to evaluate denervation. Amyloid deposition can be demonstrated by tissue biopsy of the affected organ or surrogate site, as well as bone-avid radiotracer cardiac imaging. Treatment of light-chain amyloidosis has been revolutionized by monoclonal antibodies and stem cell transplantation with improved 5-year survival up to 77%. Novel gene therapy and transthyretin stabilizers have revolutionized treatment of ATTRv, improving the course of neuropathy (less change in the modified Neuropathy Impairment Score + 7 from baseline) and quality of life. With great progress in amyloidosis therapies, early diagnosis and presymptomatic testing for ATTRv family members has become paramount. ANN NEUROL 2024;96:423-440.

Challenges associated with managing treatment complications in an older patient with cardiac amyloidosis

BackgroundAmyloidosis, particularly wild-type transthyretin amyloidosis (ATTRwt), is an increasingly recognized cause of heart failure with preserved ejection fraction in the aging population. The complexity of managing ATTRwt in older patients underscores the necessity for individualized treatment approaches, yet clinical guidelines are lacking. This case report contributes to the understanding of ATTRwt management in the elderly, emphasizing the intricacies of medication tolerance and therapeutic decision-making.Case presentationAn 83-year-old Korean man with a history of hypertension presented with dyspnea and peripheral edema. Investigations including electrocardiography, transthoracic echocardiography, cardiac magnetic resonance, and Technetium pyrophosphate scintigraphy led to a diagnosis of ATTRwt cardiac amyloidosis. Initial management with heart failure medications, including an angiotensin-converting enzyme inhibitor, diuretic, and mineralocorticoid receptor antagonist, was modified due to evolving clinical presentations, such as hypotension and onset of atrial fibrillation. Challenges included intolerance to beta-blockers and bleeding complications from direct oral anticoagulant therapy. The patient’s treatment journey highlighted the need for personalized management strategies in older ATTRwt patients.ConclusionsThis case illustrates the challenges in diagnosing and managing ATTRwt amyloidosis in the elderly, particularly the complexities in medication management due to the patient’s age, comorbid conditions, and side effects. It underscores the importance of a tailored approach in managing ATTRwt in older populations and highlights the need for ongoing research and development of treatment strategies tailored to this demographic.

Evaluation of the 2021 ESC recommendations for family screening in hereditary transthyretin cardiac amyloidosis.

The 2021 European Society of Cardiology (ESC) screening recommendations for individuals carrying a pathogenic transthyretin amyloidosis variant (ATTRv) are based on expert opinion. We aimed to (i) determine the penetrance of ATTRv cardiomyopathy (ATTRv-CM) at baseline; (ii) examine the value of serial evaluation; and (iii) establish the yield of first-line diagnostic tests (i.e. electrocardiogram, echocardiogram, and laboratory tests) as per 2021 ESC position statement. We included 159 relatives (median age 55.6 [43.2-65.9] years, 52% male) at risk for ATTRv-CM from 10 centres. The primary endpoint, ATTRv-CM diagnosis, was defined as the presence of (i) cardiac tracer uptake in bone scintigraphy; or (ii) transthyretin-positive cardiac biopsy. The secondary endpoint was a composite of heart failure (New York Heart Association class ≥II) and pacemaker-requiring conduction disorders. At baseline, 40/159 (25%) relatives were diagnosed with ATTRv-CM. Of those, 20 (50%) met the secondary endpoint. Indication to screen (≤10 years prior to predicted disease onset and absence of extracardiac amyloidosis) had an excellent negative predictive value (97%). Other pre-screening predictors for ATTRv-CM were infrequently identified variants and male sex. Importantly, 13% of relatives with ATTRv-CM did not show any signs of cardiac involvement on first-line diagnostic tests. The yield of serial evaluation (n = 41 relatives; follow-up 3.1 [2.2-5.2] years) at 3-year interval was 9.4%. Screening according to the 2021 ESC position statement performs well in daily clinical practice. Clinicians should adhere to repeating bone scintigraphy after 3 years, as progressing to ATTRv-CM without signs of ATTRv-CM on first-line diagnostic tests or symptoms is common.

A novel mutation in the transthyretin gene in amyloidosis: A cluster case report in Vietnam

Transthyretin amyloidosis (ATTR) is a slowly progressive condition characterised by the abnormal accumulation of a protein called amyloid in the body’s organs and tissues. There are three main subtypes of amyloidosis (AL), including primary or AL, secondary or AA AL, and hereditary or familial AL. Hereditary AL, which is less common, is caused by an autosomal-dominant mutation, most frequently in the transthyretin (TTR) gene, and has a more favourable prognosis. We report the case of a 51-year-old Vietnamese male who presented with severe dizziness, fainting episodes, low BMI, slow heart rate, and a blood pressure of 60/40 mmHg. The patient had a history of diges-tive disorders, weakness, and pain in the legs even after disc spine surgery. All symptoms onset occurred at 43 years old. A pathogenic mutation in the TTR gene c.209G>T was confirmed in the patient and 7 out of 15 individuals in his extended family. This is the first case reported in Vietnam diagnosing a new variant of TTR causing typical AL. Based on this study, we conclude that the TTR variant c.209G>T is a pathogenic gene. This study also emphasises the need for increased knowledge regarding AL associated with this pathogenic variant. However, further extensive research is required to provide a comprehensive understanding of the pathogenesis of TTR in the future.

EPH225 Characteristics of Patients with Transthyretin Amyloidosis and Methodological Approaches for Establishing Clinical Subtype in the Netherlands

EPH225 Characteristics of Patients with Transthyretin Amyloidosis and Methodological Approaches for Establishing Clinical Subtype in the Netherlands

Inverse correlation between age of onset and myocardial amyloid deposition quantified by 99mTc-PYP scintigraphy in patients with wild-type transthyretin amyloid cardiomyopathy.

Wild-type transthyretin amyloidosis cardiomyopathy (ATTRwt-CM) is increasingly recognized as a contributing factor to cardiac insufficiency in the elderly population. We aimed to identify the factors affecting age of onset of ATTRwt-CM, encompassing the assessment of amyloid deposition in myocardial tissue through the use of 99mTc-pyrophosphate (PYP) and clinical parameters. A retrospective investigation involving a consecutive cohort of 107 cases, each having been diagnosed with ATTRwt-CM confirmed through histopathological and genetic analysis, was performed. All patients underwent PYP scintigraphy, and the heart-to-contralateral (H/CL) ratio was calculated to measure amyloid deposition in the myocardium. Univariate and multivariate analyses were performed to identify independent predictors of the age of onset of ATTRwt-CM, considering the H/CL ratio and various clinical risk factors for heart failure. Gender (p = 0.03), Creatinine (Cr) (r = 0.32, p < 0.01), hemoglobin (Hb) (r = - 0.44, p < 0.01), albumin (Alb) (r = - 0.32, p < 0.01), brain natriuretic peptide (BNP) (r = 0.21, p = 0.03), low-density lipoprotein-cholesterol (LDL-C) (r = - 0.27, p < 0.01), and H/CL ratio (r = - 0.44, p < 0.01) were all significantly associated with the onset age. In multiple regression analysis, the independent predictive factors for the onset age of ATTRwt-CM were identified as the H/CL ratio (p < 0.01), Hb (p < 0.01), and Cr (p < 0.01). The H/CL ratio, Hb, and Cr independently affect age of onset in patients with ATTRwt-CM. The H/CL ratio is inversely correlated with age of onset, and may be the sole factor in the development of heart failure in early onset patients, while it may have a synergistic effect on heart failure with anemia and renal dysfunction in late-onset patients.

Native State Stabilization of Amyloidogenic Proteins by Kinetic Stabilizers: Inhibition of Protein Aggregation and Clinical Relevance.

Proteinopathies or amyloidoses are a group of life-threatening disorders that result from misfolding of proteins and aggregation into toxic insoluble amyloid aggregates. Amyloid aggregates have low clearance from the body due to the insoluble nature, leading to their deposition in various organs and consequent organ dysfunction. While amyloid deposition in the central nervous system leads to neurodegenerative diseases that mostly cause dementia and difficulty in movement, several other organs, including heart, liver and kidney are also affected by systemic amyloidoses. Regardless of the site of amyloid deposition, misfolding and structural alteration of the precursor proteins play the central role in amyloid formation. Kinetic stabilizers are an emerging class of drugs, which act like pharmacological chaperones to stabilize the native state structure of amyloidogenic proteins and to increase the activation energy barrier that is required for adopting a misfolded structure or conformation, ultimately leading to the inhibition of protein aggregation. In this review, we discuss the kinetic stabilizers that stabilize the native quaternary structure of transthyretin, immunoglobulin light chain and superoxide dismutase 1 that cause transthyretin amyloidoses, light chain amyloidosis and familial amyotrophic lateral sclerosis, respectively.

Transthyretin amyloid cardiomyopathy in patients with unexplained increased left ventricular wall thickness

Amyloid cardiomyopathy (CA) was previously considered a rare disease; however, rapid advancements in imaging modalities have led to an increased frequency of its diagnosis. The aim of this prospective study was to assess the prevalence and clinical phenotype of transthyretin amyloidosis (ATTR) cardiomyopathy in patients exhibiting unexplained increased left ventricular (LV) wall thickness. From 2020 to 2022, we enrolled 100 consecutive adults with unexplained increased LV wall thickness in the study. The analysis included clinical data, electrocardiography, transthoracic echocardiography, single-photon emission computed tomography/computed tomography with 3,3-disphono-1,2-propanodicarboxylic acid, genetic testing. Overall, 18% of patients were diagnosed with CA, comprising 5% with light-chain amyloidosis, and 12% with ATTR. To evaluate associations with the ATTR diagnosis, a LOGIT model and multivariate analysis were applied. Notably, age, polyneuropathy, gastropathy, carpal tunnel syndrome, lumbar spine stenosis, low voltage, ventricular arrhythmia, LV mass, LV ejection fraction, global longitudinal strain (GLS), E/A, E/E′, right ventricle (RV) thickness, right atrium area, RV VTI, TAPSE, apical sparing, ground glass appearance of myocardium, thickening of interatrial septum, thickening of valves, and the “5–5–5” sign were found to be significantly associated with ATTR (p < 0.05). The best predictive model for ATTR diagnoses exhibited an area under the curve of 0.99, including LV mass, GLS and RV thickness. This study, conducted at a cardiology referral center, revealed that a very considerable proportion of patients with unexplained increased LV wall thickness may suffer from underlying CA. Moreover, the presence of ATTR should be considered in patients with increased LV mass accompanied by reduced GLS and RV thickening.

Patisiran for the treatment of patients with p.Ile88Leu hereditary transthyretin amyloidosis: an Italian real-life experience.

Evidence on the activity of patisiran therapy in specific subgroups of patients with hereditary transthyretin amyloidosis variant (ATTRv) is still scarce. This prospective real-world study was designed to provide the first in-depth clinical data on the effectiveness of patisiran in patients with ATTRv reporting the p.Ile88Leu variant, the most widespread variant in the Emilia-Romagna regional area, which has been less represented in previous clinical trials. This prospective study evaluated all the patients with genetically proven ATTRv (p.Ile88Leu) and polyneuropathy treated with patisiran in the Emilia-Romagna referral centers for ATTRv (Institute of Neurological Sciences in Bologna and Division of Neurology in Rimini) from March 2021 to April 2023. All subjects underwent clinical and neurological evaluations at baseline and after 9-12 months of treatment. A total of 22 patients were included in the study; the median age was 73 years (IQR: 9), the age at diagnosis was 72 years (IQR: 10), and the disease duration was 1.6 years (IQR: 2.3). We observed stability of all considered neurological and cardiological parameters at 9-12 months after the beginning of patisiran treatment. Our findings support the clinical data regarding the effectiveness of patisiran in stabilizing the disease course and extend this activity to the subset of patients with the p.Ile88Leu variant.

Islands and Neurology: An Exploration into a Unique Association.

The current study investigates the intricate connection between neurology and islands shedding light on the historical, epidemiological, and genetic aspects. Based on an elaborate literature review, we identified neurological conditions having a significant clustering in an island(s), confined to a particular island(s), named after an island, and described first in an island. The genetic factors played a crucial role, uncovering disorders like Cayman ataxia, Machado Joseph disease, SGCE-mediated dystonia-myoclonus syndrome, X-linked dystonia parkinsonism, hereditary transthyretinrelated amyloidosis, Charcot Marie Tooth 4F, and progressive myoclonic epilepsy syndromes, that exhibited remarkable clustering in diverse islands. Local customs also left enduring imprints. Practices such as cannibalism in Papua New Guinea led to Kuru, while cycad seed consumption in Guam triggered Lytico-Bodig disease. Toxin-mediated neurologic disorders exhibited intricate island connections, exemplified by Minamata disease in Kyushu islands and atypical parkinsonism in French Caribbean islands. Additionally, the Cuban epidemic of amblyopia and neuropathy was associated with severe nutritional deficiencies. This study pioneers a comprehensive review narrating the genetic, environmental, and cultural factors highlighting the spectrum of neurological disorders in island settings. It enriches the medical literature with a unique understanding of the diverse influences shaping neurological health in island environments.

Advancing Transthyretin Amyloidosis Drug Development in an Evolving Treatment Landscape: Amyloidosis Forum Meeting Proceedings.

Hereditary transthyretin amyloidosis (ATTRv, also referred to as hATTR; ORPHA 271861) and wild-type ATTR amyloidosis (ATTRwt; ORPHA 330001) are rare, progressive, systemic protein misfolding disorders with heterogeneous clinical presentations. ATTRv and ATTRwt amyloidosis are characterized by the deposition of amyloid fibrils in multiple organs including the heart, nerves, eyes, and soft tissues. The management of ATTR amyloidosis is complex because of its multisystemic nature and progression despite available treatment options. Morbidity is high and there are many unmet medical needs for patients. While contemporary ATTR amyloidosis cohorts are diagnosed earlier, have lower risk disease and lower mortality compared with the previous era, these advances coupled with the emergence of effective disease-modifying therapies have confounded the design of future prospective clinical trials and interpretation of historical control data. The Amyloidosis Forum is a public-private partnership between the US Food and Drug Administration Center for Drug Evaluation and Research and the nonprofit Amyloidosis Research Consortium ( www.arci.org ). This article summarizes proceedings from the 21 June 2023 Amyloidosis Forum on advancing drug development in ATTR amyloidosis in an evolving treatment landscape. The Forum focused on elements of clinical trial design to address these challenges and discussed their strengths and weaknesses from multiple stakeholder perspectives (i.e., patient, sponsor, statistician, clinician, and regulatory authorities). Given rapid evolution of natural history in ATTR amyloidosis, the utility of historical control data is limited. Leveraging contemporary real-world data is essential for clinical trial design. Evidence generation from clinical trials should address clinically relevant questions. Key factors in successful trial design must be informed by up-to-date data on natural history, prognostic factors, clinically meaningful thresholds, and sharing available clinical trial data. The Amyloidosis Forum includes the community of patients with ATTR amyloidosis, the physicians who treat them, and the sponsors and regulators who collectively stand ready to support further studies in order to develop novel effective therapies.

Hereditary Transthyretin Amyloidosis (hATTR) with Polyneuropathy Clusters Are Located in Ancient Mining Districts: A Possible Geochemical Origin of the Disease.

Hereditary transthyretin amyloidosis (hATTR) with polyneuropathy (formerly known as Familial Amyloid Polyneuropathy (FAP)) is an endemic amyloidosis involving the harmful aggregation of proteins, most commonly transthyretin (TTR) but sometimes also apolipoprotein A-1 or gelsolin. hATTR appears to be transmitted as an autosomal dominant trait. Over 100 point mutations have been identified, with the Val30Met substitution being the most common. Yet, the mechanism of pathogenesis and the overall origin of hATTR remain unclear. Here, we argue that hATTR could be related to harmful metal exposure. hATTR incidence is unevenly distributed globally, and the three largest defined clusters exist in Japan, Portugal, and Sweden. All three disease regions are also ancient mining districts with associated metal contamination of the local environment. There are two main mechanisms for how harmful metals, after uptake into tissues and body fluids, could induce hATTR. First, the metals could directly influence the expression, function, and/or aggregation of the proteins involved in hATTR pathology. Such metal-protein interactions might constitute molecular targets for anti-hATTR drug design. Second, metal exposure could induce hATTR -associated genetic mutations, which may have happened several generations ago. These two mechanisms can occur in parallel. In conclusion, the possibility that hATTR could be related to metal exposure in geochemically defined regions deserves further attention.

Clinical outcomes of catheter ablation for atrial fibrillation, atrial flutter, and atrial tachycardia in wild-type transthyretin amyloid cardiomyopathy: a proposed treatment strategy for catheter ablation in each arrhythmia.

Wild-type transthyretin amyloid cardiomyopathy (ATTRwt-CM) is often accompanied by atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT), which are difficult to control because beta-blockers and antiarrhythmic drugs can worsen heart failure (HF). This study aimed to investigate the outcomes of catheter ablation (CA) for AF/AFL/AT in patients with ATTRwt-CM and propose a treatment strategy for CA. A cohort study was conducted on 233 patients diagnosed with ATTRwt-CM, including 54 who underwent CA for AF/AFL/AT. The background of each arrhythmia and the details of the CA and its outcomes were investigated. The recurrence-free rate of AF/AFL/AT overall in ATTRwt-CM patients with multiple CA was 70.1% at 1-year, 57.6% at 2-year, and 44.0% at 5-year follow-up, but CA significantly reduced all-cause mortality [hazard ratio (HR): 0.342, 95% confidence interval (CI): 0.133-0.876, P = 0.025], cardiovascular mortality (HR: 0.378, 95% CI: 0.146-0.981, P = 0.045), and HF hospitalization (HR: 0.488, 95% CI: 0.269-0.889, P = 0.019) compared with those without CA. There was no recurrence of the cavotricuspid isthmus (CTI)-dependent AFL, non-CTI-dependent simple AFL terminated by one linear ablation, and focal AT originating from the atrioventricular (AV) annulus or crista terminalis eventually. Twelve of 13 patients with paroxysmal AF and 27 of 29 patients with persistent AF did not have recurrence as AF. However, all three patients with non-CTI-dependent complex AFL not terminated by a single linear ablation and 10 of 13 cases with focal AT or multiple focal ATs originating beyond the AV annulus or crista terminalis recurred even after multiple CA. The outcomes of CA for ATTRwt-CM were acceptable, except for multiple focal AT and complex AFL. Catheter ablation may be aggressively considered as a treatment strategy with the expectation of improving mortality and hospitalization for HF.

Design and redesign journey of a drug for transthyretin amyloidosis.

Design and redesign journey of a drug for transthyretin amyloidosis.