Neurofilament Light Chains in Systemic Amyloidosis: A Systematic Review.

Peripheral and autonomic neuropathy are common disease manifestations in systemic amyloidosis. The neurofilament light chain (NfL), a neuron-specific biomarker, is released into the blood and cerebrospinal fluid after neuronal damage. There is a need for an early and sensitive blood biomarker for polyneuropathy, and this systematic review provides an overview on the value of NfL in the early detection of neuropathy, central nervous system involvement, the monitoring of neuropathy progression, and treatment effects in systemic amyloidosis. A literature search in PubMed, Embase, and Web of Science was performed on 14 February 2024 for studies investigating NfL levels in patients with systemic amyloidosis and transthyretin gene-variant (TTRv) carriers. Only studies containing original data were included. Included were thirteen full-text articles and five abstracts describing 1604 participants: 298 controls and 1306 TTRv carriers or patients with or without polyneuropathy. Patients with polyneuropathy demonstrated higher NfL levels compared to healthy controls and asymptomatic carriers. Disease onset was marked by rising NfL levels. Following the initiation of transthyretin gene-silencer treatment, NfL levels decreased and remained stable over an extended period. NfL is not an outcome biomarker, but an early and sensitive disease-process biomarker for neuropathy in systemic amyloidosis. Therefore, NfL has the potential to be used for the early detection of neuropathy, monitoring treatment effects, and monitoring disease progression in patients with systemic amyloidosis.

Determinants of health status in older patients with transthyretin cardiac amyloidosis: a prospective cohort study.

BACKGROUND: Whether, and to what extent, frailty and other geriatric domains are linked to health status in patients with transthyretin cardiac amyloidosis (ATTR-CA) is unknown. AIMS: To determine the association of frailty with health status [defined by the Kansas City Cardiomyopathy Questionnaire (KCCQ)] in patients with ATTR-CA. METHODS: Consecutive ATTR-CA patients undergoing cardiovascular assessment at a tertiary care clinic from September 2021 to September 2023 were invited to participate. KCCQ, frailty and social environment were recorded. Frailty was assessed using the modified Frailty Index (mFI), mapping 11 variables from the Canadian Study of Health and Aging (frailty ≥0.36). RESULTS: Of 168 screened ATTR-CA patients, 138 [83% men, median age of 79 (75-84) years] were enrolled in the study. Median KCCQ was 66 (50-75). wtATTR-CA was the most prevalent form (N = 113, 81.9%). The most frequent cardiac variant was Ile68Leu (17/25 individuals with vATTR-CA). Twenty (14.5%) patients were considered frail, and prevalence of overt disability was 6.5%. At multivariable linear regression analysis, factors associated with worsening KCCQ were age at evaluation, the mFI, NYHA Class, and NAC Score. Gender, ATTR-CA type, phenotype, and LVEF were not associated with health status. DISCUSSION: In older patients diagnosed with ATTR-CA, frailty, symptoms, and disease severity were associated with KCCQ. CONCLUSIONS: Functional status is a determinant of quality of life and health status in older individuals with a main diagnosis of ATTR-CA. Future research may provide more in-depth knowledge on the association of frailty in patients with ATTR-CA with respect to quality of life and prognosis.

The association between prealbumin concentration at admission and mortality in elderly patients with hip fractures: a cohort study.

Malnutrition is associated with complications and mortality in patients of hip fracture. Prealbumin may be more suitable than albumin to accurately predict the prognosis of hip fracture in elderly patients. We found that prealbumin concentration was nonlinearly associated with mortality in elderly patients with hip fracture, and an inflection point effect was observed. OBJECTIVE: To evaluate the association between prealbumin concentration at admission and mortality in elderly patients with hip fractures. METHODS: Elderly patients with hip fractures were screened between Jan 2015 and Sep 2019. Demographic and clinical characteristics of the patients were collected. Linear and nonlinear multivariate Cox regression models were used to identify the association between prealbumin concentration at admission and mortality. All analyses were performed using EmpowerStats and the R software. RESULTS: This cohort study included 2387 patients who met the study criteria. The mean follow-up was 37.64 months. The prealbumin concentration was 162.67 ± 43.2 mg/L. Multivariate Cox regression showed that prealbumin concentration was associated with mortality in geriatric patients with hip fracture (hazard ratio [HR] = 0.95, 95% confidence intervals [CI]: 0.93-0.97, P < 0.0001). In addition, an inflection point effect was observed in the nonlinear association. The inflection point was 162.2 mg/L. If it is less than this inflection point, then every 10 mg/L increase in prealbumin was associated with a 7% reduction in the risk of death (HR = 0.93, 95%CI: 0.90-0.96, P < 0.0001). When greater than the inflection point, there was no difference in the risk of death (HR = 0.99, 95%CI: 0.95-1.03, P = 0.5127). CONCLUSION: The prealbumin concentrations at admission were nonlinearly associated with long-term mortality in geriatric hip fractures, and 162.2 mg/L could be considered a prognostic factor of mortality risk.

Incidencia y causas de hospitalización en pacientes con amiloidosis cardiaca por transtiretina (AC-ATTR) y por cadenas ligeras (AC-AL) / Incidence and causes of hospitalization in patients with transthyretin (ATTR-CA) and light chain (AL-CA) cardiac amyloidosis

Introducción y objetivos: La amiloidosis cardiaca (AC) es una patología asociada a un elevado número de ingresos hospitalarios. Dada la escasa información disponible al respecto, planteamos un análisis de la incidencia y las causas de hospitalización en esta enfermedad.Material y métodosSe evaluaron 143 pacientes (128 por transtiretina [AC-ATTR] y 15 por cadenas ligeras [AC-AL]) incluidos en el Registro de Amiloidosis Cardiaca de Galicia (AMIGAL), recogiendo todas sus hospitalizaciones.ResultadosDurante un seguimiento mediano de 959 días se produjeron 179 hospitalizaciones no programadas (tasa de incidencia [TI] 512,6 ingresos hospitalarios por 1.000 pacientes-año), siendo las más habituales las de causa cardiovascular (n=109, TI 312,2). El motivo individual de ingreso hospitalario más frecuente fue la insuficiencia cardiaca (IC) (n=87, TI 249,2).La AC-AL se asoció con una TI de hospitalizaciones no programadas más elevada que la AC-ATTR (TI 781 vs. 483,2; HR 1,62; p=0,029) a expensas de las de causa no cardiovascular (TI 376 vs. 181,2; HR 2,07; p=0,027). La supervivencia libre de hospitalización no programada al año y a los tres años en la AC-AL fue menor que en la AC-ATTR (46,7 y 20,0% vs. 73,4 y 35,2%, respectivamente; p=0,021). (AU)

Introduction and objetives: Cardiac amyloidosis (CA) is a disorder associated with high number of hospital admissions. Given the scarce information available, we propose an analysis of the incidence and causes of hospitalization in this disease.Material and methodsOne hundred and forty-three patients [128 by transthyretin (ATTR-CA) and 15 by light chains (AL-CA)] included in Registro de Amiloidosis Cardiaca de Galicia (AMIGAL) were evaluated, including all hospitalizations.ResultsDuring a median follow-up of 959 days there were 179 unscheduled hospitalizations [incidence rate (IR) 512.6 admissions per 1000 patients-year], most common due to cardiovascular reasons (n=109, IR 312.2). Most frequent individual cause of hospitalization was heart failure (n=87, TI 249.2).AL-CA was associated with a higher IR of unscheduled hospitalizations than ATTR-CA (IR 781 vs. 483.2; HR 1.62; p=0,029) due to non-cardiovascular admissions (IR 376 vs. 181.2; HR 2.07; p=0.027). Unscheduled admission-free survival at 1 and 3 years in AL-CA was inferior than in ATTR-CA (46.7% and 20.0% vs. 73.4% and 35.2%, respectively; p=0.021). (AU)

Prognostic value of the neutrophil-to-lymphocyte ratio and C-reactive-protein-to-prealbumin ratio in hospitalized older patients with coronavirus disease 2019.

The neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein-to-prealbumin ratio (CPAR) are novel markers of inflammation. The CPAR is an indicator of inflammation and malnutrition. We evaluated NLR and CPAR in combination as indicators of disease severity and prognosis in hospitalized older patients with coronavirus disease 2019 (COVID-19). A total of 222 hospitalized patients with COVID-19 (aged > 60 years) were divided into non-severe and severe groups. The severe group was subdivided into the surviving and deceased subgroups. We retrospectively assessed the predictive power of NLR and CPAR in combination (NLR + CPAR) to determine the prognosis of hospitalized older patients with COVID-19. The NLR and CPAR were significantly higher in the severe group than in the non-severe group (P < .001). Furthermore, the NLR and CPAR were higher in the deceased subgroup than in the surviving subgroup (P < .001). Pearson correlation analysis showed a highly significant positive correlation between NLR and CPAR (P < .001, r = 0.530). NLR + CPAR showed an area under the curve of 0.827 and sensitivity of 83.9% in the severe group; the area under the curve was larger (0.925) and sensitivity was higher (87.1%) in the deceased subgroup. The receiver operating characteristic curve of NLR + CPAR was significantly different from the receiver operating characteristic curves of either biomarker alone (P < .001). Kaplan-Meier analysis showed that patients in the severe group with elevated NLR + CPAR had a significantly lower 90-day survival rate than patients who lacked this finding (odds ratio 7.87, P < .001). NLR + CPAR may enable early diagnosis and assessment of disease severity in hospitalized older patients with COVID-19. This may also enable the identification of high-risk older patients with COVID-19 at the time of admission.

Evaluation of Laboratory Parameters as Predictors of Mortality.

BACKGROUND: Evaluation of biomarkers as risk factors for mortality may provide early intervention and treatment for fatal diseases. We aimed to determine the usability of inexpensive and easily measurable tests in the differentiation of critically ill patients by investigating their relationship with mortality. METHODS: This study was executed by examining the sixth, third, and first month examinations of patients registered to the home health care services unit in 2022 before mortality due to any reason. This study was conducted by including 1,060 patients. All parameters were distributed non-parametrically. The difference between the dependent groups was evaluated with Friedman's two-way analysis of variance, and p < 0.05 was considered statistically significant. RESULTS: When the patients' premortem one-month, three-month, and six-month results were examined, there was an increase in mean platelet volume (MPV) values over time. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) also increased. In these two parameters, the difference between the first and third months and between the first and sixth months was statistically significant. Given the C-Reactive Protein (CRP)/Albumin Ratio (CAR) and CRP/Prealbumin results, a significant increase was observed in both ratios. A more than four-fold increase was observed in the CAR between the premortem first and sixth month results, which increased gradually over time and was statistically significant. Conclusions: NLR, PLR, MPV, CAR and CRP/Prealbumin values were statistically associated with mortality.

Preclinical evaluation of Tc-99m p5+14 peptide for SPECT detection of cardiac amyloidosis.

INTRODUCTION: Amyloid deposition is a cause of restrictive cardiomyopathy. Patients who present with cardiac disease can be evaluated for transthyretin (TTR)-associated cardiac amyloidosis using nuclear imaging with 99mTc-labeled pyrophosphate (PYP); however, light chain-associated (AL) cardiac amyloid is generally not detected using this tracer. As an alternative, the amyloid-binding peptide p5+14 radiolabeled with iodine-124 has been shown to be an effective pan-amyloid radiotracer for PET/CT imaging. Here, a 99mTc-labeled form of p5+14 peptide has been prepared to facilitate SPECT/CT imaging of cardiac amyloidosis. METHOD: A synthesis method suitable for clinical applications has been used to prepare 99mTc-labeled p5+14 and tested for peptide purity, product bioactivity, radiochemical purity and stability. The product was compared with99mTc-PYP for cardiac SPECT/CT imaging in a mouse model of AA amyloidosis and for reactivity with human tissue sections from AL and TTR patients. RESULTS: The 99mTc p5+14 tracer was produced with >95% yields in radiopurity and bioactivity with no purification steps required and retained over 95% peptide purity and >90% bioactivity for >3 h. In mice, the tracer detected hepatosplenic AA amyloid as well as heart deposits with uptake ~5 fold higher than 99mTc-PYP. 99mTc p5+14 effectively bound human amyloid deposits in the liver, kidney and both AL- and ATTR cardiac amyloid in tissue sections in which 99mTc-PYP binding was not detectable. CONCLUSION: 99mTc-p5+14 was prepared in minutes in >20 mCi doses with good performance in preclinical studies making it suitable for clinical SPECT/CT imaging of cardiac amyloidosis.

Perfis clínicos e genéticos de pacientes com amiloidose transtiretina hereditária e do tipo selvagem: o registro de amiloidose cardíaca transtiretina no Estado de São Paulo, Brasil (REACT-SP) / Clinical and genetic profiles of patients with hereditary and wild-type transthyretin amyloidosis: the transthyretin cardiac amyloidosis registry in the State of São Paulo, Brazil (REACT-SP)

INTRODUÇÃO: A amiloidose transtiretina (ATTR) é uma doença multissistêmica causada pela deposição de proteína fibrilar em órgãos e tecidos. Os genótipos e fenótipos da ATTR são altamente heterogêneos. MÉTODOS: Apresentamos dados sobre sinais e sintomas físicos, avaliações cardíacas e neurológicas, e genética em pacientes incluídos no Registro de Amiloidose Cardíaca Transtiretina no Estado de São Paulo (REACT-SP), Brasil. RESULTADOS: Foram incluídos 644 pacientes, sendo 505 com a forma variante (ATTRv) e 139 com a forma selvagem (ATTRwt). Dezesseis mutações diferentes foram detectadas, sendo as mais comuns Val50Met (48,3%) e V142Ile (40,8%). No geral, mais da metade dos pacientes apresentou envolvimento cardíaco, e a diferença nessa proporção entre os grupos ATTRv e ATTRwt foi significativa (43,9 vs. 89,9%; p<0,001). O fenótipo neurológico também diferiu entre ATTRv e ATTRwt (56,8 vs. 31,7%; p<0,001). O fenótipo misto foi encontrado em 25,6% da população, sem diferença significativa entre as formas de amiloidose. Um grupo de pacientes permaneceu assintomático (10,4%), com uma proporção menor de pacientes assintomáticos no grupo ATTRwt. CONCLUSÕES: Este estudo detalha o espectro clínico e genético de pacientes com ATTR em São Paulo, Brasil. Esta análise preliminar destaca a considerável heterogeneidade fenotípica das manifestações neurológicas e cardíacas em pacientes com ATTR variante e ATTR do tipo selvagem.

Amyloid Typing in Cardiac Amyloidosis Using Western Blotting.

BACKGROUND: Cardiac amyloidosis (CA) is characterized by the extracellular deposition of misfolded protein in the heart. Precise identification of the amyloid type is often challenging, but critical, since the treatment and prognosis depend on the disease form and the type of deposited amyloid. Coexistence of clinical conditions such as old age, monoclonal gammopathy, chronic inflammation, or peripheral neuropathy in a patient with cardiomyopathy creates a differential diagnosis between the major types of CA: amyloidosis light chains (AL), amyloidosis transthyretin (ATTR) and amyloidosis A (AA). OBJECTIVES: To demonstrate the utility of the Western blotting (WB)-based amyloid typing method in patients diagnosed with cardiac amyloidosis where the type of amyloid was not obvious based on the clinical context. METHODS: Congo red positive endomyocardial biopsy specimens were studied in patients where the type of amyloid was uncertain. Amyloid proteins were extracted and identified by WB. Mass spectrometry (MS) of the electrophoretically resolved protein-in-gel bands was used for confirmation of WB data. RESULTS: WB analysis allowed differentiation between AL, AA, and ATTR in cardiac biopsies based on specific immunoreactivity of the electrophoretically separated proteins and their characteristic molecular weight. The obtained results were confirmed by MS. CONCLUSIONS: WB-based amyloid typing method is cheaper and more readily available than the complex and expensive gold standard techniques such as MS analysis or immunoelectron microscopy. Notably, it is more sensitive and specific than the commonly used immunohistochemical techniques and may provide an accessible diagnostic service to patients with amyloidosis in Israel.

Composite of KLVFF-Transthyretin-Penetratin and Manganese Dioxide Nanoclusters: A Multifunctional Agent against Alzheimer's ß-Amyloid Fibrillogenesis.

Design of amyloid ß-protein (Aß) inhibitors is considered an effective strategy for the prevention and treatment of Alzheimer's disease (AD). However, the limited blood-brain barrier (BBB) penetration and poor Aß-targeting capability restricts the therapeutic efficiency of candidate drugs. Herein, we have proposed to engineer transthyretin (TTR) by fusion of the Aß-targeting peptide KLVFF and cell-penetrating peptide Penetratin to TTR, and derived a fusion protein, KLVFF-TTR-Penetratin (KTP). Moreover, to introduce the scavenging activity for reactive oxygen species (ROS), a nanocomposite of KTP and manganese dioxide nanoclusters (KTP@MnO2) was fabricated by biomineralization. Results revealed that KTP@MnO2 demonstrated significantly enhanced inhibition on Aß aggregation as compared to TTR. The inhibitory effect was increased from 18%, 33%, and 49% (10, 25, and 50 µg/mL TTR, respectively) to 52%, 81%, and 100% (10, 25, and 50 µg/mL KTP@MnO2). In addition, KTP@MnO2 could penetrate the BBB and target amyloid plaques. Moreover, multiple ROS, including hydroxyl radicals, superoxide radicals, hydrogen peroxide, and Aß-induced-ROS, which cannot be scavenged by TTR, were scavenged by KTP@MnO2, thus resulting in the mitigation of cellular oxidative damages. More importantly, cell culture and in vivo experiments with AD nematodes indicated that KTP@MnO2 at 50 µg/mL increased the viability of Aß-treated cells from 66% to more than 95%, and completely cleared amyloid plaques in AD nematodes and extended their lifespan by 7 d. Overall, despite critical aspects such as the stability, metabolic distribution, long-term biotoxicity, and immunogenicity of the nanocomposites in mammalian models remaining to be investigated, this work has demonstrated the multifunctionality of KTP@MnO2 for targeting Aß in vivo, and provided new insights into the design of multifunctional nanocomposites of protein-metal clusters against AD.

Structures and Dynamics of ß-Rich Oligomers of ATTR (105-115) Assembly.

Transthyretin (TTR) is a tetrameric homologous protein that can dissociate into monomers. Misfolding and aggregation of TTR can lead to amyloid transthyretin amyloidosis (ATTR), which can cause many diseases (e.g., senile systemic amyloidosis, familial amyloid cardiomyopathy, and familial amyloid polyneuropathy). Despite growing evidence indicating that small oligomers play a critical role in regulating cytotoxicity, the structures of these oligomeric intermediates and their conformational transformations are still unclear, impeding our understanding of neurodegenerative mechanisms and the development of therapeutics targeting early aggregation species. The TTR monomer protein consists of various fragments prone to self-aggregation, including the residue 105-115 sequence. Therefore, our study investigated the assembly progress of ATTR (105-115) peptides using all-atom molecular dynamics simulations. The findings indicate that the probability of ß-sheet content increases with increasing numbers of peptides. Additionally, interactions between hydrophobic residues L110 and L111 are crucial for the formation of a ß-rich oligomer formation. These ß-rich oligomers may adopt ß-barrel conformations, potentially toxic oligomer species. Free-energy analysis reveals that ß-barrel conformations serve as intermediates for these ß-rich oligomers. Our insights into the structural ensemble dynamics of ATTR (105-115) contribute to understanding the physical mechanisms underlying the ß-barrel oligomers of ATTR. These findings may shed light on the pathological role of ATTR in neurodegenerative diseases and offer potential therapeutic targets.

Late-onset familial amyloidosis polyneuropathy associated with c.186G>C in transthyretin.

INTRODUCTION: The most common form of hereditary amyloidosis is associated with variants of transthyretin (TTR). Familial amyloidosis polyneuropathy associated with variants of TTR (FAP-TTR) is an infrequent, multisystemic disease, with predominant involvement of the peripheral nervous system. More than 130 pathogenic variants have been identified so far and most of them are amyloidogenic, being Val30Met the most frequently described. CASE REPORT: A 74 year-old male was evaluated for progressive decreased sensitivity and associated loss of strength in four limbs in the previous two years, needing assistance for walking. Areflexia, bilateral tibialis anterior and gastrocnemius atrophy, bilateral anesthesia and apalesthesia were found in lower limbs. Bilateral hypoesthesia was reported in upper limbs. No painful dysesthesia, hyperalgesia or allodynia were found. DNA sequencing of the TTR gene led to the detection of the variant c.186G>C in heterozygous state. The resulting variant (Glu62Asp), located in the critical functional domain, has not been published before. CONCLUSION: The importance of considering late onset, sporadic FAP-TTR as a differential diagnosis of cryptogenic polyneuropathy is highlighted.

Introducción: La forma más común de amiloidosis hereditaria está asociada con variantes de la transtiretina. La polineuropatía amiloidótica familiar asociada con variantes de la TTR (FAP-TTR) es una enfermedad multisistémica poco frecuente, con afectación predominante del sistema nervioso periférico. Hasta ahora se han identificado más de 130 variantes patogénicas y la mayoría de ellas son amiloidogénicas, siendo Val30Met la más frecuentemente descrita. Caso clínico: Un paciente de 74 años fue evaluado por disminución progresiva de la sensibilidad y pérdida asociada de fuerza en las cuatro extremidades de dos años de evolución, necesitando ayuda para caminar. En las extremidades inferiores se observó arreflexia, atrofia bilateral del tibial anterior y del gastrocnemio, anestesia bilateral y apalestesia. Los miembros superiores presentaban hipoestesia bilateral. No se observaron disestesias dolorosas, hiperalgesia ni alodinia. La secuenciación del ADN del gen TTR permitió detectar la variante c.186G>C en estado heterocigoto. La variante resultante (Glu62Asp), localizada en el dominio funcional crítico de la proteína, no ha sido informada con anterioridad. Conclusión: Se destaca la importancia de considerar la FAP-TTR esporádica de aparición tardía como un diagnóstico diferencial de la polineuropatía criptogénica.

Prevalence of transthyretin cardiac amyloidosis in patients with high-degree AV block.

OBJECTIVE: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an infiltrative cardiac disorder caused by deposition of wild type or mutated transthyretin. As ATTR-CM is associated with conduction disease, we sought to determine its prevalence in patients with idiopathic high-degree atrioventricular (AV) block requiring permanent pacemaker (PPM) implantation. METHODS: Consecutive patients aged 70-85 years undergoing PPM implantation for idiopathic high-degree AV block between November 2019 and November 2021 were offered a 3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scan. Demographics, comorbidities, electrocardiographic and imaging data from the time of device implantation were retrospectively collected. RESULTS: 39 patients (79.5% male, mean (SD) age at device implantation 76.2 (2.9) years) had a DPD scan. 3/39 (7.7%, all male) had a result consistent with ATTR-CM (Perugini grade 2 or 3). Mean (SD) maximum wall thickness of those with a positive DPD scan was 19.0 mm (3.6 mm) vs 11.4 mm (2.7 mm) in those with a negative scan (p=0.06). All patients diagnosed with ATTR-CM had spinal canal stenosis and two had carpal tunnel syndrome. CONCLUSIONS: ATTR-CM should be considered in older patients requiring permanent pacing for high-degree AV block, particularly in the presence of left ventricular hypertrophy, carpal tunnel syndrome or spinal canal stenosis.

Histological Typing in Patients With Cardiac Amyloidosis: JACC Review Topic of the Week.

Cardiac amyloidosis is increasingly recognized as a treatable form of heart failure. Highly effective specific therapies have recently become available for the 2 most frequent forms of cardiac amyloidosis: immunoglobulin light chain amyloidosis and transthyretin (ATTR) amyloidosis. Nevertheless, initiation of specific therapies requires recognition of cardiac amyloidosis and appropriate characterization of the amyloid type. Although noninvasive diagnosis is possible for ATTR cardiac amyloidosis, histological demonstration and typing of amyloid deposits is still required for a substantial number of patients with ATTR and in all patients with light chain amyloidosis and other rarer forms of cardiac amyloidosis. Amyloid histological typing can be performed using different techniques: mass spectrometry, immunohistochemistry, and immunoelectron microscopy. This review describes which patients require histological confirmation of cardiac amyloidosis along with when and how to type amyloid deposits in histologic specimens. Furthermore, it covers the characteristics and limitations of the different typing methods that are available in clinical practice.