Systemic immunoglobulin light chain amyloidosis

Graded Organ Response and Progression Criteria for Kidney Immunoglobulin Light Chain Amyloidosis

Importance

Kidney light chain (AL) amyloidosis is associated with a risk of progression to kidney replacement therapy (KRT) and death. Several studies have shown that a greater reduction in proteinuria following successful anticlonal therapy is associated with improved outcomes.

Objective

To validate graded kidney response criteria and their association with kidney and overall survival (OS).

Design, Setting, and Participants

This retrospective, multicenter cohort was conducted at 10 referral centers for amyloidosis from 2010 to 2015 and included patients with kidney AL amyloidosis that was evaluable for kidney response and who achieved at least hematologic partial response within 12 months of diagnosis. The median follow-up was 69 (54-88) months. Data analysis was conducted in 2023.

Exposure

Four kidney response categories based on the reduction in pretreatment 24-hour urine protein (24-hour UP) levels: complete response (kidCR, 24-hour UP ≤200 mg), very good partial response (kidVGPR, >60% reduction in 24-hour UP), partial response (kidPR, 31%-60% reduction), and no response (kidNR, ≤30% reduction). Kidney response was assessed at landmark points (6, 12, and 24 months) and best kidney response.

Main Outcomes and Measures

Cumulative incidence of progression to KRT and OS.

Results

Seven-hundred and thirty-two patients (335 women [45.8%]) were included, with a median (IQR) age of 63 (55-69) years. The median (IQR) baseline 24-hour proteinuria and estimated glomerular filtration rate was 5.3 (2.8-8.5) g per 24 hours and 72 (48-92) mL/min/1.73m2, respectively. In a competing-risk analysis, the 5-year cumulative incidence rates of progression to KRT decreased with deeper kidney responses as early as 6 months from therapy initiation (11%, 12%, 2.1%, and 0% for kidNR, kidPR, kidVGPR, and kidCR, respectively; P = .002) and were maintained at 12 months and 24 months and best kidney response. Patients able to achieve kidCR/kidVGPR by 24 months and at best response had significantly better OS compared with kidPR/kidNR. Kidney progression, defined as a 25% or greater decrease in estimated glomerular filtration rate, was associated with cumulative incidence of progression to KRT and OS.

Conclusions and Relevance

The results of this cohort study suggest that graded kidney response criteria offers clinically and prognostically meaningful information for treating patients with kidney AL amyloidosis. The response criteria potentially inform kidney survival based on the depth of reduction in 24-hour proteinuria levels and demonstrate an OS advantage for those able to achieve kidCR/kidVGPR compared with kidPR/kidNR. Taken together, achievement of at least kidVGPR by 12 months is needed to ultimately improve kidney and patient survival.

Multiple myeloma with secondary amyloidosis: Dysphagia as the first symptom: A case report

RATIONALE

Multiple myeloma (MM) with secondary amyloidosis (AL) is a rare clonal plasma cell proliferation disease, which causes dysfunction of multiple organs and tissues. We report a case of dysphagia as the first symptom in a patient with MM and secondary AL.

PATIENT CONCERNS

The patient was a 73-year-old female, was admitted to our hospital, because of progressive dysphagia for 4 months and limb weakness for 1 month.

DIAGNOSES

The bone marrow smear and pathology diagnosis revealed the presence of MM, while the biceps myopathy diagnosis indicated AL.

INTERVENTIONS

The VCD regimen consisted of bortezomib at a dosage of 1.9 mg on days 1, 8, 15, and 22, cyclophosphamide 0.4 g on days 1, 8, and 15, and dexamethasone at a dosage of 40 mg on days 1, 8, 15, and 22. The patient simultaneously received comprehensive treatment including anti-infective therapy, enhanced cardiac function, and nutritional support.

OUTCOMES

The M protein in the blood and urine protein were negative, indicating a reduction in bone marrow plasma cells to 2%. Flow cytometric analysis revealed a minimal percentage 0.04%. As a result, complete remission was achieved.

LESSONS

The clinical manifestations of MM exhibit a wide range, with the symptoms of secondary injury causing significant disturbing, while the atypical symptoms of extramedullary manifestations pose challenges in diagnosing the disease.

Clonal hematopoiesis of indeterminate potential in patients with immunoglobulin light-chain AL amyloidosis

ABSTRACT

Immunoglobulin light-chain (AL) amyloidosis is characterized by the deposition of misfolded monoclonal free light chains, with cardiac complications accounting for patient mortality. Clonal hematopoiesis of indeterminate potential (CHIP) has been associated with worse cardiovascular outcomes in the general population. Its significance in AL amyloidosis remains unclear. We collected clinical information and outcome data on 76 patients with a diagnosis of AL amyloidosis who underwent deep targeted sequencing for myeloid neoplasia-associated mutations between April 2018 and August 2023. Variant allele frequency was set at 2% to call CHIP-associated mutations. CHIP mutations were present in patients with AL amyloidosis at a higher frequency compared with age-matched control individuals. Sixteen patients (21%) had at least 1 CHIP mutation. DNMT3A was the most frequent mutation (7/16; 44%). Compared with patients without CHIP, patients with CHIP had a higher prevalence of t(11;14) translocation (69% vs 25%, respectively; P = .004). Furthermore, among patients with renal involvement, those with CHIP had a lower Palladini renal stage (P = .001). At a median follow-up of 32.5 months, the presence of CHIP was not associated with worse overall survival or major organ dysfunction progression-free survival. Larger studies and longer follow-up are needed to better define the impact of CHIP in patients with AL amyloidosis.

Effect of dynamic exclusion and the use of FAIMS, DIA and MALDI-mass spectrometry imaging with ion mobility on amyloid protein identification

Amyloidosis is a disease characterized by local and systemic extracellular deposition of amyloid protein fibrils where its excessive accumulation in tissues and resistance to degradation can lead to organ failure. Diagnosis is challenging because of approximately 36 different amyloid protein subtypes. Imaging methods like immunohistochemistry and the use of Congo red staining of amyloid proteins for laser capture microdissection combined with liquid chromatography tandem mass spectrometry (LMD/LC-MS/MS) are two diagnostic methods currently used depending on the expertise of the pathology laboratory. Here, we demonstrate a streamlined in situ amyloid peptide spatial mapping by Matrix Assisted Laser Desorption Ionization-Mass Spectrometry Imaging (MALDI-MSI) combined with Trapped Ion Mobility Spectrometry for potential transthyretin (ATTR) amyloidosis subtyping. While we utilized the standard LMD/LC-MS/MS workflow for amyloid subtyping of 31 specimens from different organs, we also evaluated the potential introduction in the MS workflow variations in data acquisition parameters like dynamic exclusion, or testing Data Dependent Acquisition combined with High-Field Asymmetric Waveform Ion Mobility Spectrometry (DDA FAIMS) versus Data Independent Acquisition (DIA) for enhanced amyloid protein identification at shorter acquisition times. We also demonstrate the use of Mascot's Error Tolerant Search and PEAKS de novo sequencing for the sequence variant analysis of amyloidosis specimens.

A patient with AL amyloidosis presenting with refractory tuberculosis, chest tightness and hypotension: case report

INTRODUCTION

Immunoglobulin light chain (AL) amyloidosis presents a clinical spectrum characterized by diverse manifestations and involvement of multiple organs, posing a significant diagnostic challenge for physicians.

METHODS AND RESULTS

We present a case of a patient admitted to our hospital due to recurrent cough and sputum, which was initially diagnosed as refractory tuberculosis. Throughout his hospitalization, the patient experienced distressing symptoms, including uncontrollable chest tightness, hypotension, and fever. Noteworthy observations included a persistent elevation in cardiac biomarkers, indicative of cardiac damage. Bronchoalveolar lavage revealed the presence of various pathogenic microorganisms, while bone marrow flow cytometry demonstrated the existence of clonal plasma cells. Additionally, the urine free light chain assay detected the presence of M protein, and the positive congo red staining of the abdominal wall fat biopsy confirmed amyloid deposition in the tissues. Taking into account the patient's clinical presentation and the examination findings, we reached a conclusive diagnosis of immunoglobulin light chain (AL) amyloidosis.

CONCLUSION

This case serves as a reminder for physicians to consider rare diseases like AL amyloidosis when patients present with symptoms involving multiple organ systems such as heart, lung and kidney that are unresponsive to conventional treatment options.

Pathway for Development and Validation of Multi-domain Endpoints for Amyloid Light Chain (AL) Amyloidosis

Immunoglobin light chain (AL) amyloidosis is a rare disease in which a plasma cell dyscrasia leads to deposition of insoluble amyloid fibrils in multiple organs. To facilitate development of new therapies for this heterogenous disease, a public-private partnership was formed between the nonprofit Amyloidosis Research Consortium and the US Food and Drug Administration Center for Drug Evaluation and Research. In 2020, the Amyloidosis Forum launched an initiative to identify clinical trial endpoints and analytic strategies across affected organ systems and life impacts via specialized working groups. This review summarizes the proceedings of the Statistical Group and proposes a pathway for development and validation of multi-domain endpoints (MDEs) for potential use in AL amyloidosis clinical trials. Specifically, drawing on candidate domain-specific endpoints recommended by each organ-specific working group, different approaches to constructing MDEs were considered. Future studies were identified to assess the validity, meaningfulness and performance of MDEs through use of natural history and clinical trial data. Ultimately, for drug development, the context of use in a regulatory evaluation, the specific patient population, and the investigational therapeutic mechanism should drive selection of appropriate endpoints. MDEs for AL amyloidosis, once developed and validated, will provide important options for advancing patient-focused drug development in this multi-system disease.

Current status and prospect of anti-amyloid fibril therapy in AL amyloidosis

Amyloid light-chain (AL) amyloidosis is a rare hematological disease that produces abnormal monoclonal immunoglobulin light chains to form amyloid fibrils that are deposited in tissues, resulting in organ damage and dysfunction. Advanced AL amyloidosis has a very poor prognosis with a high risk of early mortality. The combination of anti-plasma cell therapy and amyloid fibrils clearance is the optimal treatment strategy, which takes into account both symptoms and root causes. However, research on anti-amyloid fibrils lags far behind research on anti-plasma cells, and there is currently no approved treatment that could clear amyloid fibrils. Nevertheless, anti-amyloid fibril therapies are being actively investigated recently and have shown potential in clinical trials. In this review, we aim to outline the preclinical work and clinical efficacy of fibril-directed therapies for AL amyloidosis.

Pathophysiology of Cardiac Amyloidosis

Amyloidosis refers to a heterogeneous group of disorders sharing common pathophysiological mechanisms characterized by the extracellular accumulation of fibrillar deposits consisting of the aggregation of misfolded proteins. Cardiac amyloidosis (CA), usually caused by deposition of misfolded transthyretin or immunoglobulin light chains, is an increasingly recognized cause of heart failure burdened by a poor prognosis. CA manifests with a restrictive cardiomyopathy which progressively leads to biventricular thickening, diastolic and then systolic dysfunction, arrhythmias, and valvular disease. The pathophysiology of CA is multifactorial and includes increased oxidative stress, mitochondrial damage, apoptosis, impaired metabolism, and modifications of intracellular calcium balance.

Computational evidences of a misfolding event in an aggregation-prone light chain preceding the formation of the non-native pathogenic dimer

Antibody light chain amyloidosis is a disorder in which protein aggregates, mainly composed of immunoglobulin light chains, deposit in diverse tissues impairing the correct functioning of organs. Interestingly, due to the high susceptibility of antibodies to mutations, AL amyloidosis appears to be strongly patient-specific. Indeed, every patient will display their own mutations that will make the proteins involved prone to aggregation thus hindering the study of this disease on a wide scale. In this framework, determining the molecular mechanisms that drive the aggregation could pave the way to the development of patient-specific therapeutics. Here, we focus on a particular patient-derived light chain, which has been experimentally characterized. We investigated the early phases of the aggregation pathway through extensive full-atom molecular dynamics simulations, highlighting a structural rearrangement and the exposure of two hydrophobic regions in the aggregation-prone species. Next, we moved to consider the pathological dimerization process through docking and molecular dynamics simulations, proposing a dimeric structure as a candidate pathological first assembly. Overall, our results shed light on the first phases of the aggregation pathway for a light chain at an atomic level detail, offering new structural insights into the corresponding aggregation process.

Waldenström Macroglobulinemia - A State-of-the-Art Review: Part 1: Epidemiology, Pathogenesis, Clinicopathologic Characteristics, Differential Diagnosis, Risk Stratification, and Clinical Problems

Waldenström macroglobulinemia (WM) is an infrequent variant of lymphoma, classified as a B-cell malignancy identified by the presence of IgM paraprotein, infiltration of clonal, small lymphoplasmacytic B cells in the bone marrow, and the MYD88 L265P mutation, which is observed in over 90% of cases. The direct invasion of the malignant cells into tissues like lymph nodes and spleen, along with the immune response related to IgM, can also lead to various health complications, such as cytopenias, hyperviscosity, peripheral neuropathy, amyloidosis, and Bing-Neel syndrome. Chemoimmunotherapy has historically been considered the preferred treatment for WM, wherein the combination of rituximab and nucleoside analogs, alkylating drugs, or proteasome inhibitors has exhibited notable efficacy in inhibiting tumor growth. Recent studies have provided evidence that Bruton Tyrosine Kinase inhibitors (BTKI), either used independently or in conjunction with other drugs, have been shown to be effective and safe in the treatment of WM. The disease is considered to be non-curable, with a median life expectancy of 10 to 12 years.

Prognostic Value of Left Ventricular 18F-Florbetapir Uptake in Systemic Light-Chain Amyloidosis

BACKGROUND

Positron emission tomography/computed tomography (PET/CT) with 18F-florbetapir, a novel amyloid-targeting radiotracer, can quantify left ventricular (LV) amyloid burden in systemic light-chain (AL) amyloidosis. However, its prognostic value is not known.

OBJECTIVES

The authors' aim was to evaluate the prognostic value of LV amyloid burden quantified by 18F-florbetapir PET/CT, and to identify mechanistic pathways mediating its association with outcomes.

METHODS

A total of 81 participants with newly diagnosed AL amyloidosis underwent 18F-florbetapir PET/CT imaging. Amyloid burden was quantified using 18F-florbetapir LV uptake as percent injected dose. The Mayo stage for AL amyloidosis was determined using troponin T, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and free light chain levels. Major adverse cardiac events (MACE) were defined as all-cause death, heart failure hospitalization, or cardiac transplantation within 12 months.

RESULTS

Among participants (median age, 61 years; 57% males), 36% experienced MACE, increasing from 7% to 63% across tertiles of LV amyloid burden (P < 0.001). LV amyloid burden was associated with MACE (HR: 1.46; 95% CI: 1.16-1.83; P = 0.001). However, this association became nonsignificant when adjusted for Mayo stage. In mediation analysis, the association between LV amyloid burden and MACE was mediated by NT-proBNP (P < 0.001), a marker of cardiomyocyte stretch and heart failure, and a component of Mayo stage.

CONCLUSIONS

In this first study to link cardiac 18F-florbetapir uptake to subsequent outcomes, LV amyloid burden estimated by percent injected dose predicted MACE in AL amyloidosis. This effect was not independent of Mayo stage and was mediated primarily through NT-proBNP. These findings provide novel insights into the mechanism linking myocardial amyloid deposits to MACE.

Options for Rescue Treatment of Patients with AL Amyloidosis Exposed to Upfront Daratumumab

PURPOSE OF REVIEW

This review aims to assess the therapeutic strategies available for relapsed/refractory patients with immunoglobulin light chain (AL) amyloidosis who received upfront daratumumab-based regimens.

RECENT FINDINGS

The treatment landscape of AL amyloidosis has changed radically thanks to the introduction in the upfront setting of daratumumab in combination with bortezomib, cyclophosphamide and dexamethasone (DaraCyBorD) which improved patients' outcomes increasing the rate of hematologic and organ responses. However, many patients eventually relapse or are refractory to daratumumab and the best salvage therapy is not well defined yet. In this contest, we reviewed the available therapeutic options after daratumumab failure, and we look towards the current advances in Bcl-2 inhibitors, novel immunotherapeutic agents as chimeric antigen receptor (CAR-T) therapy and bispecific antibodies (bsAbs). Relapsed/refractory AL amyloidosis represent an unmet clinical need and novel targeted drugs require urgent prospective assessment.

Development and Validation of Staging Systems for AA Amyloidosis

Key Points

Patients with AA amyloidosis and age ≥65 years, eGFR <45 ml/min per 1.73 m2, and N -terminal type-B natriuretic peptide >1000 ng/L and/or type-B natriuretic peptide >130 ng/L at diagnosis have poorer survival. Proteinuria >3.0 g/24 hours and eGFR <35 ml/min per 1.73 m2 identify patients at high risk of progression to end-stage kidney failure. Prognostic stratification in AA amyloidosis can be easily made by staging systems, similarly to AL and transthyretin amyloidosis.

Background

The kidney is involved in almost 100% of cases of AA amyloidosis, a rare disease caused by persistent inflammation with long overall survival but frequent progression to kidney failure. Identification of patients with advanced disease at diagnosis is difficult, given the absence of validated staging systems.

Methods

Patients with newly diagnosed AA amyloidosis from the Pavia (n =233, testing cohort) and Heidelberg (n =243, validation cohort) centers were included in this study. Cutoffs of continuous variables were determined by receiver operating characteristic analysis predicting death or dialysis at 24 months. Prognostic factors included in staging systems were identified by multivariable models in the testing cohort.

Results

Age ≥65 years, eGFR <45 ml/min per 1.73 m2, and elevated natriuretic peptides (type-B natriuretic peptide >130 ng/L and/or N -terminal type-B natriuretic peptide >1000 ng/L) were associated with overall survival and included in the staging system (all with simplified coefficients 1). Mean 36-month overall survival was lower with higher staging system scores (score 0–1: 92%; score 2: 72%; score 3: 32%). These results were confirmed in the validation cohort. For kidney failure, variables selected to enter in the staging system model were proteinuria >3 g/24 hour and eGFR <35 ml/min per 1.73 m2 (both with simplified coefficients 1). The 36-month cumulative incidence of kidney failure was higher with higher staging system scores (score 0: 0%; score 1: 24%; score 2: 51%). Again, similar results were obtained in validation cohort.

Conclusions

We identified and validated biomarker-based staging systems for overall survival and kidney failure in AA amyloidosis.

Advancing Renal Amyloidosis Care: The Role of Modern Diagnostic Techniques with the Potential of Enhancing Patient Outcomes

Renal amyloidosis is a set of complex disorders characterized by the deposition of amyloid proteins in the kidneys, which causes gradual organ damage and potential kidney failure. Recent developments in diagnostic methods, particularly mass spectrometry and proteome profiling, have greatly improved the accuracy of amyloid typing, which is critical for disease management. These technologies provide extensive insights into the specific proteins involved, allowing for more targeted treatment approaches and better patient results. Despite these advances, problems remain, owing to the heterogeneous composition of amyloid proteins and the varying efficacy of treatments based on amyloid type. Access to sophisticated diagnostics and therapy varies greatly, highlighting the global difference in renal amyloidosis management. Future research is needed to investigate next-generation sequencing and gene-editing technologies, like clustered regularly interspaced short palindromic repeats (CRISPR), which promise more profound insights into the genetic basis of amyloidosis.

Amyloid detection in neurodegenerative diseases using MOFs

Neurodegenerative diseases (amyloid diseases such as Alzheimer's and Parkinson's), stemming from protein misfolding and aggregation, encompass a spectrum of disorders with severe systemic implications. Timely detection is pivotal in managing these diseases owing to their significant impact on organ function and high mortality rates. The diverse array of amyloid disorders, spanning localized and systemic manifestations, underscores the complexity of these conditions and highlights the need for advanced detection methods. Traditional approaches have focused on identifying biomarkers using imaging techniques (PET and MRI) or invasive procedures. However, recent efforts have focused on the use of metal-organic frameworks (MOFs), a versatile class of materials known for their unique properties, in revolutionizing amyloid disease detection. The high porosity, customizable structures, and biocompatibility of MOFs enable their integration with biomolecules, laying the groundwork for highly sensitive and specific biosensors. These sensors have been employed using electrochemical and photophysical techniques that target amyloid species under neurodegenerative conditions. The adaptability of MOFs allows for the precise detection and quantification of amyloid proteins, offering potential advancements in early diagnosis and disease management. This review article delves into how MOFs contribute to detecting amyloid diseases by categorizing their uses based on different sensing methods, such as electrochemical (EC), electrochemiluminescence (ECL), fluorescence, Förster resonance energy transfer (FRET), up-conversion luminescence resonance energy transfer (ULRET), and photoelectrochemical (PEC) sensing. The drawbacks of MOF biosensors and the challenges encountered in the field are also briefly explored from our perspective.

A Simple Frailty Score Predicts Survival and Early Mortality in Systemic AL Amyloidosis

Systemic AL amyloidosis is a challenging disease for which many patients are considered frail in daily clinical practice. However, no study has so far addressed frailty and its impact on the outcome of these patients. We built a simple score to predict mortality based on three frailty-associated variables: age, ECOG performance status (<2 vs. ≥2) and NT-proBNP (<8500 vs. ≥8500 ng/L). Four-hundred and sixteen consecutive newly diagnosed patients diagnosed at ten sites from the Spanish Myeloma Group were eligible for the study. The score was developed in a derivation cohort from a referral center, and it was externally validated in a multicenter cohort. Multivariate analysis showed that the three variables were independent predictors of survival. The score was able to discriminate four groups of patients in terms of overall survival and early mortality in both cohorts. Comorbidity was also analyzed with the Charlson comorbidity index, but it did not reach statistical significance in the model. A nomogram was created to easily estimate the mortality risk of each patient at each time point. This score is a simple, robust, and efficient approach to dynamically assess frailty-dependent mortality both at diagnosis and throughout follow-up. The optimal treatment for frail AL amyloidosis patients remains to be determined but we suggest that the estimation of frailty-associated risk could complement current staging systems, adding value in clinical decision-making in this complex scenario.

Minimal residual disease in systemic light chain amyloidosis: a systematic review and meta-analysis

PURPOSE

Minimal residual disease (MRD) is a validated prognostic factor in several hematological malignancies. However, its role in systemic light chain (AL) amyloidosis remains controversial, and this systematic review and meta-analysis aims to fill this gap.

METHODS

We searched for relevant studies on Pubmed, Embase, and Cochrane Controlled Register of Trials, nine studies involving 451 patients were included and meta-analyzed. This systematic review has been registered in PROSPERO (CRD42023494169).

RESULTS

Our study found that in the group of patients who achieved very good partial response (VGPR) or better, MRD negativity was correlated with higher cardiac and renal response rates [pooled risk ratio (RR) = 0.74 (95% CI 0.62-0.89), 0.74 (95% CI 0.64-0.87), respectively]. Patients with MRD positivity had a higher hematologic progression rate within two years after MRD detection [pooled RR = 10.31 (95% CI 2.02-52.68)]; and a higher risk of hematologic + organ progression in the first year [pooled RR = 12.57 (95% CI 1.73-91.04)]. Moreover, MRD negativity was correlated with a better progression-free survival (PFS) [pooled hazard ratio (HR) = 0.27 (95% CI 0.17-0.45)]; but it did not significantly improve the overall survival (OS) [pooled HR = 0.34 (95% CI 0.11-1.07)].

CONCLUSION

In AL amyloidosis, our study supports that MRD negativity correlates with higher cardiac or renal response rates and indicates a better PFS in the follow-up. However, the correlation between OS and the status of MRD is not significant.

Truncation of the constant domain drives amyloid formation by immunoglobulin light chains

AL amyloidosis is a life-threatening disease caused by deposition of immunoglobulin light chains. While the mechanisms underlying light chains amyloidogenesis in vivo remain unclear, several studies have highlighted the role that tissue environment and structural amyloidogenicity of individual light chains have in the disease pathogenesis. AL natural deposits contain both full-length light chains and fragments encompassing the variable domain (VL) as well as different length segments of the constant region (CL), thus highlighting the relevance that proteolysis may have in the fibrillogenesis pathway. Here, we investigate the role of major truncated species of the disease-associated AL55 light chain that were previously identified in natural deposits. Specifically, we study structure, molecular dynamics, thermal stability, and capacity to form fibrils of a fragment containing both the VL and part of the CL (133-AL55), in comparison with the full-length protein and its variable domain alone, under shear stress and physiological conditions. Whereas the full-length light chain forms exclusively amorphous aggregates, both fragments generate fibrils, although, with different kinetics, aggregate structure, and interplay with the unfragmented protein. More specifically, the VL-CL 133-AL55 fragment entirely converts into amyloid fibrils microscopically and spectroscopically similar to their ex vivo counterpart and increases the amorphous aggregation of full-length AL55. Overall, our data support the idea that light chain structure and proteolysis are both relevant for amyloidogenesis in vivo and provide a novel biocompatible model of light chain fibrillogenesis suitable for future mechanistic studies.

Abnormal global longitudinal strain and reduced serum inflammatory markers in cardiac AL amyloidosis patients without significant amyloid fibril deposition

Background

Cardiac dysfunction in AL amyloidosis is thought to be partly related to the direct impact of AL LCs on cardiomyocyte function, with the degree of dysfunction at diagnosis as a major determinant of clinical outcomes. Nonetheless, mechanisms underlying LC-induced myocardial toxicity are not well understood.

Methods

We identified gene expression changes correlating with human cardiac cells exposed to a cardiomyopathy-associated κAL LC. We then sought to confirm these findings in a clinical dataset by focusing on clinical parameters associated with the pathways dysregulated at the gene expression level.

Results

Upon exposure to a cardiomyopathy-associated κAL LC, cardiac cells exhibited gene expression changes related to myocardial contractile function and inflammation, leading us to hypothesize that there could be clinically detectable changes in GLS on echocardiogram and serum inflammatory markers in patients. Thus, we identified 29 patients with normal IVSd but abnormal cardiac biomarkers suggestive of LC-induced cardiac dysfunction. These patients display early cardiac biomarker staging, abnormal GLS, and significantly reduced serum inflammatory markers compared to patients with clinically evident amyloid fibril deposition.

Conclusion

Collectively, our findings highlight early molecular and functional signatures of cardiac AL amyloidosis, with potential impact for developing improved patient biomarkers and novel therapeutics.

Cardiac Amyloidosis Due to Transthyretin Protein: A Review

Importance

Systemic amyloidosis from transthyretin (ATTR) protein is the most common type of amyloidosis that causes cardiomyopathy.

Observations

Transthyretin (TTR) protein transports thyroxine (thyroid hormone) and retinol (vitamin A) and is synthesized predominantly by the liver. When the TTR protein misfolds, it can form amyloid fibrils that deposit in the heart causing heart failure, heart conduction block, or arrhythmia such as atrial fibrillation. The biological processes by which amyloid fibrils form are incompletely understood but are associated with aging and, in some patients, affected by inherited variants in the TTR genetic sequence. ATTR amyloidosis results from misfolded TTR protein deposition. ATTR can occur in association with normal TTR genetic sequence (wild-type ATTR) or with abnormal TTR genetic sequence (variant ATTR). Wild-type ATTR primarily manifests as cardiomyopathy while ATTR due to a genetic variant manifests as cardiomyopathy and/or polyneuropathy. Approximately 50 000 to 150 000 people in the US have heart failure due to ATTR amyloidosis. Without treatment, heart failure due to ATTR amyloidosis is associated with a median survival of approximately 5 years. More than 130 different inherited genetic variants in TTR exist. The most common genetic variant is Val122Ile (pV142I), an allele with an origin in West African countries, that is present in 3.4% of African American individuals in the US or approximately 1.5 million persons. The diagnosis can be made using serum free light chain assay and immunofixation electrophoresis to exclude light chain amyloidosis combined with cardiac nuclear scintigraphy to detect radiotracer uptake in a pattern consistent with amyloidosis. Loop diuretics, such as furosemide, torsemide, and bumetanide, are the primary treatment for fluid overload and symptomatic relief of patients with ATTR heart failure. An ATTR-directed therapy that inhibited misfolding of the TTR protein (tafamidis, a protein stabilizer), compared with placebo, reduced mortality from 42.9% to 29.5%, reduced hospitalizations from 0.7/year to 0.48/year, and was most effective when administered early in disease course.

Conclusions and Relevance

ATTR amyloidosis causes cardiomyopathy in up to approximately 150 000 people in the US and tafamidis is the only currently approved therapy. Tafamidis slowed progression of ATTR amyloidosis and improved survival and prevented hospitalization, compared with placebo, in people with ATTR-associated cardiomyopathy.

An Unusual Diagnosis in a Single-Lung Transplant Recipient: Secondary Amyloidosis

Silicosis, a progressive, fibrotic occupational lung disease with no known treatment, is an uncommon indication for lung transplant. There is a paucity of research on patients with silicosis who have received lung transplants. The long-term consequences of the native lung in patients with severe chronic silicosis who have had a single-lung transplant are also of interest. We present a case of amyloidosis in a patient who underwent a single-lung transplant for silicosis.

Kinetic evidence for multiple aggregation pathways in antibody light chain variable domains

Aggregation of antibody light chain proteins is associated with the progressive disease light chain amyloidosis. Patient-derived amyloid fibrils are formed from light chain variable domain residues in non-native conformations, highlighting a requirement that light chains unfold from their native structures in order to aggregate. However, mechanistic studies of amyloid formation have primarily focused on the self-assembly of natively unstructured peptides, and the role of native state unfolding is less well understood. Using a well-studied light chain variable domain protein known as WIL, which readily aggregates in vitro under conditions where the native state predominates, we asked how the protein concentration and addition of pre-formed fibril "seeds" alter the kinetics of aggregation. Monitoring aggregation with thioflavin T fluorescence revealed a distinctly non-linear dependence on concentration, with a maximum aggregation rate observed at 8 μM protein. This behavior is consistent with formation of alternate aggregate structures in the early phases of amyloid formation. Addition of N- or C-terminal peptide tags, which did not greatly affect the folding or stability of the protein, altered the concentration dependence of aggregation. Aggregation rates increased in the presence of pre-formed seeds, but this effect did not eliminate the delay before aggregation and became saturated when the proportion of seeds added was greater than 1 in 1600. The complexity of aggregation observed in vitro highlights how multiple species may contribute to amyloid pathology in patients.

Amyloidosis and Considerations for the Hand Surgeon

Amyloidosis can lead to cardiac, renal, and other multiorgan failure. New treatments have become available that can prolong survival but rely on early diagnosis. Manifestations of amyloidosis in hand surgery include carpal tunnel syndrome, trigger finger, peripheral neuropathy, and spontaneous distal biceps rupture. Often, these can predate systemic amyloidosis, offering hand surgeons an opportunity to diagnose patients with amyloidosis before systemic disease, refer them for treatment, and potentially alter disease course and prolong survival. In this review, we describe the pathophysiology and two most common subtypes of amyloidosis seen by hand surgeons. We provide guidance on biopsy practices and referral for patients with amyloidosis. Lastly, we provide a brief overview of the treatments for amyloidosis and their effect on disease course.

Arrhythmias and Device Therapies in Cardiac Amyloidosis

Cardiac amyloidosis is caused by amyloid fibrils that deposit in the myocardial interstitium, causing restrictive cardiomyopathy and eventually death. The electromechanical, inflammatory, and autonomic changes due to amyloid deposition result in arrhythmias. Atrial fibrillation is by far the most common arrhythmia. The rate control strategy is generally poorly tolerated due to restrictive filling physiology and heart rate dependance, favoring adoption of the rhythm control strategy. Anticoagulation for stroke prophylaxis is warranted, irrespective of CHA2DS2-VASc score in patients with a favorable bleeding profile; data on left appendage closure devices are still insufficient. Ventricular arrhythmias are also not uncommon, and the role of implantable cardioverter-defibrillator in cardiac amyloidosis is controversial. There is no evidence of improvement in outcomes when used for primary prevention in these patients. Bradyarrhythmia is most commonly associated with sudden cardiac death in cardiac amyloidosis. Pacemaker implantation can help provide symptomatic relief but does not confer mortality benefit.

Rare vertebral pathological fracture in primary amyloidosis

Spinal involvement in primary amyloidosis is an exceedingly rare condition, presenting with typical pathological fracture symptoms that are often indistinguishable from other pathologies such as bone metastasis, metabolic disorders and infections. Histopathological studies for tissue diagnosis are the cornerstone of a definitive diagnosis, leading to successful treatment. Early diagnosis and intervention play a pivotal role in the care of patients with amyloidosis. Here, we present a unique case of a pathological fracture in the L4 vertebra following minor trauma. This fracture manifested with pain, instability and limitations in daily activities in a patient who had already been diagnosed with systemic amyloidosis and was undergoing chemotherapy. This case represents a distinct instance of vertebral involvement in amyloidosis and was managed with both chemotherapy and surgical intervention to address the spinal pathology, resulting in favourable outcomes.

Misfolded protein oligomers: mechanisms of formation, cytotoxic effects, and pharmacological approaches against protein misfolding diseases

The conversion of native peptides and proteins into amyloid aggregates is a hallmark of over 50 human disorders, including Alzheimer's and Parkinson's diseases. Increasing evidence implicates misfolded protein oligomers produced during the amyloid formation process as the primary cytotoxic agents in many of these devastating conditions. In this review, we analyze the processes by which oligomers are formed, their structures, physicochemical properties, population dynamics, and the mechanisms of their cytotoxicity. We then focus on drug discovery strategies that target the formation of oligomers and their ability to disrupt cell physiology and trigger degenerative processes.

Hepatomegaly and jaundice as the presenting symptoms of systemic light-chain amyloidosis: A case report

BACKGROUND

Light chain (AL) amyloidosis is a plasma cell dyscrasia characterized by the pathologic production and extracellular tissue deposition of fibrillar proteins derived from immunoglobulin AL fragments secreted by a clone of plasma cells, which leads to progressive dysfunction of the affected organs. The two most commonly affected organs are the heart and kidneys, and liver is rarely the dominant affected organ with only 3.9% of cases, making them prone to misdiagnosis and missed diagnosis.

CASE SUMMARY

A 65-year-old woman was admitted with a 3-mo history of progressive jaundice and marked hepatomegaly. Initially, based on enhanced computed tomography scan and angiography, Budd-Chiari syndrome was considered and balloon dilatation of significant hepatic vein stenoses was performed. However, additional diagnostic procedures, including liver biopsy and bone marrow-examination, revealed immunoglobulin kapa AL amyloidosis with extensive liver involvement and hepatic vascular compression. The disease course was progressive and fatal, and the patient eventually died 5 mo after initial presentation of symptoms.

CONCLUSION

AL amyloidosis with isolated liver involvement is very rare, and can be easily misdiagnosed as a vascular disease.

Cardiac Troponin in Patients With Light Chain and Transthyretin Cardiac Amyloidosis: JACC: CardioOncology State-of-the-Art Review

Cardiac amyloidosis (CA) is an infiltrative disease caused by amyloid fibril deposition in the myocardium; the 2 forms that most frequently involve the heart are amyloid light chain (AL) and amyloid transthyretin (ATTR) amyloidosis. Cardiac troponin (cTn) is the biomarker of choice for the detection of myocardial injury and is frequently found to be elevated in patients with CA, particularly with high-sensitivity assays. Multiple mechanisms of myocardial injury in CA have been proposed, including cytotoxic effect of amyloid precursors, interstitial amyloid fibril infiltration, coronary microvascular dysfunction, amyloid- and non-amyloid-related coronary artery disease, diastolic dysfunction, and heart failure. Regardless of the mechanisms, cTn values have relevant prognostic (and potentially diagnostic) implications in both AL and ATTR amyloidosis. In this review, the authors discuss the significant aspects of cTn biology and measurement methods, potential mechanisms of myocardial injury in CA, and the clinical application of cTn in the management of both AL and ATTR amyloidosis.

Re-Engineering Therapeutic Anti-Aβ Monoclonal Antibody to Target Amyloid Light Chain

Amyloidosis involves the deposition of misfolded proteins. Even though it is caused by different pathogenic mechanisms, in aggregate, it shares similar features. Here, we tested and confirmed a hypothesis that an amyloid antibody can be engineered by a few mutations to target a different species. Amyloid light chain (AL) and β-amyloid peptide (Aβ) are two therapeutic targets that are implicated in amyloid light chain amyloidosis and Alzheimer's disease, respectively. Though crenezumab, an anti-Aβ antibody, is currently unsuccessful, we chose it as a model to computationally design and prepare crenezumab variants, aiming to discover a novel antibody with high affinity to AL fibrils and to establish a technology platform for repurposing amyloid monoclonal antibodies. We successfully re-engineered crenezumab to bind both Aβ42 oligomers and AL fibrils with high binding affinities. It is capable of reversing Aβ42-oligomers-induced cytotoxicity, decreasing the formation of AL fibrils, and alleviating AL-fibrils-induced cytotoxicity in vitro. Our research demonstrated that an amyloid antibody could be engineered by a few mutations to bind new amyloid sequences, providing an efficient way to reposition a therapeutic antibody to target different amyloid diseases.

Systemic Amyloidosis and Kidney Transplantation: An Update

Amyloidosis is a heterogeneous disorder characterized by abnormal protein aggregate deposition that often leads to kidney involvement and end-stage kidney disease. With advancements in diagnostic techniques and treatment options, the prevalence of patients with amyloidosis requiring chronic dialysis has increased. Kidney transplantation is a promising avenue for extending survival and enhancing quality of life in these patients. However, the complex and heterogeneous nature of amyloidosis presents challenges in determining optimal referral timing for transplantation and managing post-transplantation course. This review focuses on recent developments and outcomes of kidney transplantation for amyloidosis-related end-stage kidney disease. This review also aims to guide clinical decision-making and improve management of patients with amyloidosis-associated kidney disease, offering insights into optimizing patient selection and post-transplant care for favorable outcomes.

Valvular heart disease in patients with cardiac amyloidosis

Cardiac amyloidosis (CA) is an underdiagnosed condition caused by the deposition of misfolded proteins, namely immunoglobulin light chains and transthyretin, in the extracellular spaces of the heart. Any cardiovascular structure can be affected by amyloid infiltration, including the valves. Amyloid accumulation within the cardiac valves may lead to their structural and functional impairment, with a profound impact on patients' prognosis and quality of life. The most common forms of valvular disease in CA are aortic stenosis (AS), mitral regurgitation (MR), and tricuspid regurgitation (TR). CA and AS share similar risk factors, disease mechanisms, and remodeling patterns, which make their diagnosis particularly challenging. Patients with both CA and AS experience worse outcomes than CA or AS alone, and transcatheter aortic valve replacement may represent a useful therapeutic strategy in this population. Data on MR and TR are quite limited and mainly coming from case reports or small series. This review paper will summarize our current understanding on the epidemiology, disease mechanisms, echocardiographic features, clinical implications, and therapeutic options of AS, MR, and TR in patients with CA.

Immune checkpoint expression patterns on T cell subsets in light-chain amyloidosis: VISTA, PD-1, and TIGIT as potential therapeutic targets

Amyloid light chain (AL) amyloidosis is a rare plasma cell dyscrasia with dismal prognosis. This study aims to investigate the T-cell immune checkpoint expression patterns in systemic AL amyloidosis and its relationship with clinicobiological traits. We examined the frequencies of V-domain immunoglobulin suppressor of T cell activation+ (VISTA+), programmed cell death 1+ (PD-1+), T cell immunoglobulin and mucin-domain-containing-3+ (Tim-3+), T cell immunoreceptor with Ig and ITIM domains+ (TIGIT+) T cells in peripheral blood (PB) and bone marrow (BM) from 19 patients with newly diagnosed AL amyloidosis. Patients with AL amyloidosis had significantly higher percentages of VISTA+ and PD-1+ T cells in PB than healthy individuals (HIs), with no statistical differences in BM. The percentages of some double-positive T cells in PB were also considerably higher in AL amyloidosis than those in HIs. Additionally, the patients with renal involvement had more PD-1+ and TIGIT+ T cells than the patients without, and PD-1+CD3+%, PD-1+CD4+%, PD-1+Treg% were positively correlated with 24-hour proteinuria levels. Furthermore, the AL amyloidosis patients had higher counts of PD-1+ Treg in PB than multiple myeloma (MM) patients, while the MM patients had higher counts of TIGIT+ T cells than AL amyloidosis patients. Collectively, this is the first report of elevated proportions of VISTA+ and PD-1+ T cells in PB of AL amyloidosis patients, indicating an immunosuppressive milieu, and the increased PD-1+ and TIGIT+ T cells were associated with renal damage. VISTA, PD-1, and TIGIT may be potential targets for reversing T-cell exhaustion in AL amyloidosis.

Expression and Clinical Significance of Non B Cell-Derived Immunoglobulins in the Urinary System and Male Reproductive System

The urinary system comprises kidneys, ureters, bladder, and urethra with its primary function being excretion, referring to the physiological process of transporting substances that are harmful or surplus out of the body. The male reproductive system consists of gonads (testis), vas deferens, and accessory glands such as the prostate. According to classical immunology theory, the tissues and organs mentioned above are not thought to produce immunoglobulins (Igs), and any Ig present in the relevant tissues under physiological and pathological conditions is believed to be derived from B cells. For instance, most renal diseases are associated with uncontrolled inflammation caused by pathogenic Ig deposited in the kidney. Generally, these pathological Igs are presumed to be produced by B cells. Recent studies have demonstrated that renal parenchymal cells can produce and secrete Igs, including IgA and IgG. Glomerular mesangial cells can express and secrete IgA, which is associated with cell survival and adhesion. Likewise, human podocytes demonstrate the ability to produce and secrete IgG, which is related to cell survival and adhesion. Furthermore, renal tubular epithelial cells also express IgG, potentially involved in the epithelial-mesenchymal transition (EMT). More significantly, renal cell carcinoma, bladder cancer, and prostate cancer have been revealed to express high levels of IgG, which promotes tumour progression. Given the widespread Ig expression in the urinary and male reproductive systems, continued efforts to elucidate the roles of Igs in renal physiological and pathological processes are necessary.

Autologous Stem Cell Transplant in Hodgkin's and Non-Hodgkin's Lymphoma, Multiple Myeloma, and AL Amyloidosis

Human body cells are stem cell (SC) derivatives originating from bone marrow. Their special characteristics include their capacity to support the formation and self-repair of the cells. Cancer cells multiply uncontrollably and invade healthy tissues, making stem cell transplants a viable option for cancer patients undergoing high-dose chemotherapy (HDC). When chemotherapy is used at very high doses to eradicate all cancer cells from aggressive tumors, blood-forming cells and leukocytes are either completely or partially destroyed. Autologous stem cell transplantation (ASCT) is necessary for patients in those circumstances. The patients who undergo autologous transplants receive their own stem cells (SCs). The transplanted stem cells first come into contact with the bone marrow and then undergo engraftment, before differentiating into blood cells. ASCT is one of the most significant and innovative strategies for treating diseases. Here we focus on the treatment of Hodgkin's lymphoma, non-Hodgkin's lymphoma, multiple myeloma, and AL amyloidosis, using ASCT. This review provides a comprehensive picture of the effectiveness and the safety of ASCT as a therapeutic approach for these diseases, based on the currently available evidence.

Nanobodies counteract the toxicity of an amyloidogenic light chain by stabilizing a partially open dimeric conformation

Light chain amyloidosis (AL) is a systemic disease where fibrillar deposition of misfolded immunoglobulin light chains (LCs) severely affects organ function and results in poor prognosis for patients, especially when heart involvement is severe. Particularly relevant in this context is the cardiotoxicity exerted by still uncharacterized soluble LC species. Here, with the final goal of identifying alternative therapeutic strategies to tackle AL amyloidosis, we produced five llama-derived nanobodies (Nbs) specific against H3, a well-characterized amyloidogenic and cardiotoxic LC from an AL patient with severe cardiac involvement. We found that Nbs are specific and potent agents capable of abolishing H3 soluble toxicity in C. elegans in vivo model. Structural characterization of H3-Nb complexes revealed that the protective effect of Nbs is related to their ability to bind to the H3 VL domain and stabilise an unexpected partially open LC dimer in which the two VL domains no longer interact with each other. Thus, while identifying potent inhibitors of LC soluble toxicity, we also describe the first non-native structure of an amyloidogenic LC that may represent a crucial step in toxicity and aggregation mechanisms.

Monoclonal Gammopathy of Undetermined Cardiovascular Significance; Current Evidence and Novel Insights

Monoclonal gammopathy of undetermined significance (MGUS) is a premalignant condition characterized by the presence of low levels of a monoclonal protein in the serum and a low percentage of clonal plasma cells in the bone marrow. MGUS may progress to multiple myeloma or other plasma cell disorders at a rate of 1% annually. However, MGUS may also have adverse effects on the cardiovascular system independent of its malignant potential. Emerging data have shown that MGUS is associated with cardiovascular disease. The mechanisms underlying this association are not fully understood but may involve genetic abnormalities, vascular calcification, cryoglobulinemia, cold agglutinin disease, autoantibodies and the direct or indirect effects of the monoclonal protein on the vascular endothelium. Herein, we review current evidence in this field and we suggest that patients with MGUS may benefit from regular cardiovascular risk assessment to prevent severe cardiovascular complications, in parallel with close hematological follow-up to monitor potential disease progression.

Role of complementarity-determining regions 1 and 3 in pathologic amyloid formation by human immunoglobulin κ1 light chains

BACKGROUND

Immunoglobulin light chain (LC) amyloidosis is a life-threatening disease complicated by vast numbers of patient-specific mutations. We explored 14 patient-derived and engineered proteins related to κ1-family germline genes IGKVLD-33*01 and IGKVLD-39*01.

METHODS

Hydrogen-deuterium exchange mass spectrometry analysis of conformational dynamics in recombinant LCs and their fragments was integrated with studies of thermal stability, proteolytic susceptibility, amyloid formation and amyloidogenic sequence propensity. The results were mapped on the structures of native and fibrillary proteins.

RESULTS

Proteins from two κ1 subfamilies showed unexpected differences. Compared to their germline counterparts, amyloid LC related to IGKVLD-33*01 was less stable and formed amyloid faster, whereas amyloid LC related to IGKVLD-39*01 had similar stability and formed amyloid slower, suggesting different major factors influencing amyloidogenesis. In 33*01-related amyloid LC, these factors involved destabilization of the native structure and probable stabilization of amyloid. The atypical behavior of 39*01-related amyloid LC stemmed from increased dynamics/exposure of amyloidogenic segments in βC'V and βEV that could initiate aggregation and decreased dynamics/exposure near the Cys23-Cys88 disulfide.

CONCLUSIONS

The results suggest distinct amyloidogenic pathways for closely related LCs and point to the complementarity-defining regions CDR1 and CDR3, linked via the conserved internal disulfide, as key factors in amyloid formation.

First Norwegian case of hereditary ATTR amyloidosis with a novel transthyretin variant

An earlier healthy 64-year-old man with previous surgery for bilateral carpal tunnel syndrome (CTS) in his 50s, presented with dyspnoea on exertion. Cardiac amyloidosis was suspected due to "red flag" signs and symptoms. Further investigations with scintigraphy and genetic testing confirmed the diagnosis of hereditary ATTR variant (ATTRv) amyloidosis. This is the first case report of ATTRv amyloidosis in a patient of Norwegian origin and is caused by the mutation E54A (p.E74A) in the transthyretin (TTR) gene. This mutation is previously not reported in international databases. Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed disease with a poor prognosis. Early recognition remains essential to afford the best treatment efficacy.

Assessing the prognostic utility of hematologic response for overall survival in patients with newly diagnosed AL amyloidosis: results of a meta-analysis

OBJECTIVES

Amyloid light-chain (AL) amyloidosis is a rare disease characterized by amyloid fibril deposits made up of toxic light chains causing progressive organ dysfunction and death. Recent studies suggest that hematologic response may be an important prognostic indicator of overall survival (OS) in AL amyloidosis. The aim of this study was to evaluate the trial-level association between hematologic complete response (CR) or very good partial response or better (≥ VGPR) and OS in newly diagnosed patients.

METHODS

Studies were identified via systematic literature review. Pooled effect estimates were generated by a random-effects model.

RESULTS

Nine observational studies reporting hematologic CR or ≥VGPR and OS hazard ratios (HRs) were included in the meta-analysis. Achieving hematologic CR was associated with improved OS (HR, 0.21; 95% confidence interval [CI] 0.13-0.34). Achieving ≥ VGPR was also associated with improved OS (HR 0.21; 95% CI 0.17-0.26). Results of a sensitivity analysis excluding one outlier study revealed no heterogeneity and a better overall HR estimate. Potential limitations of this meta-analysis include the small number of eligible studies (consistent with the rarity of the disease) and inconsistencies in reporting of results.

CONCLUSIONS

Overall, our findings support the use of deep hematologic response (CR or ≥VGPR) as a clinical trial endpoint in newly diagnosed AL amyloidosis. This study provides evidence that early hematologic response is a strong patient-level surrogate for long-term OS in patients with AL amyloidosis receiving frontline therapy. Structured data collection of depth of response in future trials will further strengthen these observations.

Alzheimer's disease: The role of proteins in formation, mechanisms, and new therapeutic approaches

Alzheimer's disease (AD) is a progressive neurological disorder that affects the central nervous system (CNS), leading to memory and cognitive decline. In AD, the brain experiences three main structural changes: a significant decrease in the quantity of neurons, the development of neurofibrillary tangles (NFT) composed of hyperphosphorylated tau protein, and the formation of amyloid beta (Aβ) or senile plaques, which are protein deposits found outside cells and surrounded by dystrophic neurites. Genetic studies have identified four genes associated with autosomal dominant or familial early-onset AD (FAD): amyloid precursor protein (APP), presenilin 1 (PS1), presenilin 2 (PS2), and apolipoprotein E (ApoE). The formation of plaques primarily involves the accumulation of Aβ, which can be influenced by mutations in APP, PS1, PS2, or ApoE genes. Mutations in the APP and presenilin (PS) proteins can cause an increased amyloid β peptides production, especially the further form of amyloidogenic known as Aβ42. Apart from genetic factors, environmental factors such as cytokines and neurotoxins may also have a significant impact on the development and progression of AD by influencing the formation of amyloid plaques and intracellular tangles. Exploring the causes and implications of protein aggregation in the brain could lead to innovative therapeutic approaches. Some promising therapy strategies that have reached the clinical stage include using acetylcholinesterase inhibitors, estrogen, nonsteroidal anti-inflammatory drugs (NSAIDs), antioxidants, and antiapoptotic agents. The most hopeful therapeutic strategies involve inhibiting activity of secretase and preventing the β-amyloid oligomers and fibrils formation, which are associated with the β-amyloid fibrils accumulation in AD. Additionally, immunotherapy development holds promise as a progressive therapeutic approach for treatment of AD. Recently, the two primary categories of brain stimulation techniques that have been studied for the treatment of AD are invasive brain stimulation (IBS) and non-invasive brain stimulation (NIBS). In this article, the amyloid proteins that play a significant role in the AD formation, the mechanism of disease formation as well as new drugs utilized to treat of AD will be reviewed.

Patient Journey Toward a Diagnosis of Light Chain Amyloidosis in a National Sample: Cross-Sectional Web-Based Study

BACKGROUND

Systemic light chain (AL) amyloidosis is a rare and multisystem disease associated with increased morbidity and a poor prognosis. Delayed diagnoses are common due to the heterogeneity of the symptoms. However, real-world insights from Chinese patients with AL amyloidosis have not been investigated.

OBJECTIVE

This study aimed to describe the journey to an AL amyloidosis diagnosis and to build an in-depth understanding of the diagnostic process from the perspective of both clinicians and patients to obtain a correct and timely diagnosis.

METHODS

Publicly available disease-related content from social media platforms between January 2008 and April 2021 was searched. After performing data collection steps with a machine model, a series of disease-related posts were extracted. Natural language processing was used to identify the relevance of variables, followed by further manual evaluation and analysis.

RESULTS

A total of 2204 valid posts related to AL amyloidosis were included in this study, of which 1968 were posted on haodf.com. Of these posts, 1284 were posted by men (median age 57, IQR 46-67 years); 1459 posts mentioned renal-related symptoms, followed by heart (n=833), liver (n=491), and stomach (n=368) symptoms. Furthermore, 1502 posts mentioned symptoms related to 2 or more organs. Symptoms for AL amyloidosis most frequently mentioned by suspected patients were nonspecific weakness (n=252), edema (n=196), hypertrophy (n=168), and swelling (n=140). Multiple physician visits were common, and nephrologists (n=265) and hematologists (n=214) were the most frequently visited specialists by suspected patients for initial consultation. Additionally, interhospital referrals were also commonly seen, centralizing in tertiary hospitals.

CONCLUSIONS

Chinese patients with AL amyloidosis experienced referrals during their journey toward accurate diagnosis. Increasing awareness of the disease and early referral to a specialized center with expertise may reduce delayed diagnosis and improve patient management.

Safety and Efficacy of Propylene Glycol-Free Melphalan in Patients with AL Amyloidosis Undergoing Autologous Stem Cell Transplantation: Results of a Phase II Study

Patients with systemic light chain (AL) amyloidosis undergoing treatment with high-dose melphalan and autologous stem cell transplantation (HDM/SCT) may develop renal and cardiac toxicities potentially exacerbated by the co-solvent propylene glycol in conventional melphalan formulations. We investigated the safety and efficacy of propylene glycol-free melphalan (PGF-Mel) during HDM/SCT in patients with AL amyloidosis (ClinicalTrials.gov identifier NCT02994784). The primary objective of this phase II, open-label study was evaluation for renal dysfunction, new cardiac arrhythmias, and postural hypotension related to autonomic dysfunction. Secondary objectives included time to neutrophil and platelet engraftment, treatment-related mortality (TRM), overall hematologic response, organ response, and number of peritransplantation hospitalizations. Twenty-eight patients with AL amyloidosis enrolled, of whom 27 underwent HDM/SCT. PGF-Mel at 140 to 200 mg/m2 was administered i.v. in 2 equally divided doses. Patients were monitored for up to 30 days after the last administration of PGF-Mel to assess for treatment-related toxicity. Patients were followed for 12 months from the time of treatment with HDM/SCT for evaluation of hematologic and organ responses. Kaplan-Meier analysis was used to estimate progression-free survival. Two patients (7%) developed renal dysfunction, 5 (19%) experienced new cardiac arrhythmias, and 3 (11%) developed orthostatic hypotension. All patients achieved neutrophil and platelet engraftment, at a median of 10 days and 17 days post-HDM/SCT, respectively. TRM on day +100 was 0%. Peritransplantation hospitalization was required for 23 patients (85%). The most common nonhematologic adverse events were diarrhea (93%), fatigue (82%), and nausea (74%). At 6 months post-HDM/SCT, hematologic complete response or very good partial response occurred in 66% of the patients. At 12 months post-HDM/SCT, renal response occurred in 12 of 23 (52%) patients with renal involvement, and cardiac response occurred in 3 of 11 (27%) patients with evaluable cardiac involvement. Our data indicate that PGF-Mel is safe and efficacious as a high-dose conditioning regimen for autologous SCT in patients with AL amyloidosis.

Peripheral Nervous, Hepatic, and Gastrointestinal Endpoints for AL Amyloidosis Clinical Trials: Report from the Amyloidosis Forum Multi-organ System Working Group

Systemic immunoglobulin light chain (AL) amyloidosis is a heterogeneous rare disease driven by a destructive monoclonal gammopathy and typified by misfolded immunoglobulin light and/or heavy chains which aggregate and deposit in organs as insoluble amyloid fibrils. Disease heterogeneity is driven by the degree of multi-systemic involvement; cardiac, renal, neurological, and gastrointestinal (GI) systems are affected to varying degrees in different patients. While prognosis is primarily driven by hematologic response to treatment and outcomes associated with cardiac events and overall survival, the involvement of the peripheral nervous, hepatic, and GI systems can also have a significant impact on patients. The Amyloidosis Forum ( https://amyloidosisforum.org ) is a public-private partnership between the nonprofit Amyloidosis Research Consortium ( www.arci.org ) and the US Food and Drug Administration (FDA) Center for Drug Evaluation and Research formed to advance drug development for the treatment of systemic amyloid disorders. A series of virtual workshops focused on the development of novel, patient-relevant endpoint components and analytical strategies for clinical trials in AL amyloidosis. This review summarizes the proceedings and recommendations of the Multi-Systemic Working Group which identified, reviewed, and prioritized endpoints relevant to the impacts of AL amyloidosis on the peripheral nervous, hepatic, and GI systems. The Working Group comprised amyloidosis experts, patient representatives, statisticians, and representatives from the FDA, Medicines and Healthcare products Regulatory Agency (MHRA), and pharmaceutical companies. Prioritized neuropathy/autonomic endpoints included a modified form of the Neuropathy Impairment Score (NIS + 7) and the Composite Autonomic Symptom Score (COMPASS-31), respectively. Alkaline phosphatase was identified as the most relevant indicator of liver involvement and disease progression. Following extensive review of potential GI endpoints, the Working Group identified multiple exploratory endpoints. These recommended components will be further explored through evaluation of clinical trial datasets and possible integration into composite endpoint analysis.

Epidemiology and clinical outcomes of light-chain amyloidosis in Sweden: A nationwide population-based study

OBJECTIVES

This study evaluated data from six Swedish national registries to fill current evidence gaps on the epidemiology, clinical burden, and overall survival (OS) associated with light-chain (AL) amyloidosis.

METHODS

Patients newly diagnosed with AL amyloidosis were identified using six linked Swedish nationwide population-based registers. For each case, individuals from the general population were selected and matched with a maximum ratio of 1:5 based on age, sex, calendar year, and county.

RESULTS

846 patients newly diagnosed with AL amyloidosis and 4227 demographically matched individuals were identified. From 2011 to 2019, annual AL amyloidosis incidence increased from 10.5 to 15.1 cases per million. At baseline, patients with AL amyloidosis had a significantly higher disease burden including higher rates of cardiac and renal failure relative to the comparison group. Among patients with AL amyloidosis, 21.5% had incident heart failure and 17.1% had incident renal failure after initial diagnosis. Median OS for patients with AL amyloidosis was 56 months versus not reached in the matched general population comparison group.

CONCLUSION

The incidence of newly diagnosed AL amyloidosis in Sweden increased over time with AL amyloidosis being associated with a higher risk of cardiac/renal failure and all-cause mortality compared with the general population.

Predictors of treatment response and survival outcomes in patients with advanced cardiac AL amyloidosis

Patients with advanced cardiac immunoglobulin light chain (AL) amyloidosis have a poor prognosis. Early hematologic and cardiac responses can prolong survival, but predictors of these outcomes have yet to be clarified. We report on 142 patients with newly diagnosed stage IIIb AL amyloidosis. After a median follow-up of 60 months, the median overall survival (OS) was 9 months. Independent baseline factors associated with shorter OS were symptom onset to diagnosis >6 months (hazard ratio [HR], 1.94; P = .003); bone marrow plasmacytosis ≥ 10% (HR, 1.98; P = .01); troponin I > 0.635 ng/mL (HR, 1.62; P = .04); New York Heart Association class III or IV (HR, 1.67; P = .04); and 6-minute walk test distance < 200 m (HR, 1.85; P = .01). Early hematologic (within 1 month) and cardiac (within 3 months) responses were significantly associated with longer survival. In a 1-month landmark analysis, patients with a hematologic very good partial response, partial response, and no response had a median OS of 47, 25, and 5 months, respectively (P < .0001). Patients with cardiac response at 3 months had significantly longer OS (47 vs 11 months; P < .0001). On multivariable modeling, bortezomib use was associated with early hematologic and cardiac responses and longer OS. Symptom onset to diagnosis duration of >6 months and difference between the involved and uninvolved free light chain > 350 mg/L were independently associated with lower odds of an early cardiac response. This study identified factors predictive of treatment outcomes and survival in advanced cardiac AL amyloidosis.

Thromboembolic and Bleeding Events in Transthyretin Amyloidosis and Coagulation System Abnormalities: A Review

Transthyretin amyloidosis (ATTR) is a group of diseases caused by the deposition of insoluble fibrils derived from misfolded transthyretin, which compromises the structure and function of various organs, including the heart. Thromboembolic events and increased bleeding risk are among the most important complications of ATTR, though the underlying mechanisms are not yet fully understood. Transthyretin plays a complex role in the coagulation cascade, contributing to the activation and regulation of the coagulation and fibrinolytic systems. The prevalence of atrial fibrillation, cardiac mechanical dysfunction, and atrial myopathy in patients with ATTR may contribute to thrombosis, though such events may also occur in patients with a normal sinus rhythm and rarely in properly anticoagulated patients. Haemorrhagic events are modest and mainly linked to perivascular amyloid deposits with consequent capillary fragility and coagulation anomalies, such as labile international-normalised ratio during anticoagulant therapy. Therefore, it is paramount to carefully stratify the thrombotic and haemorrhagic risks, especially when initiating anticoagulant therapy. Our review aims to ascertain the prevalence of thromboembolic and haemorrhagic events in ATTR and identify potential risk factors and predictors and their impact on antithrombotic therapy.

First third-generation CAR T cell application targeting CD19 for the treatment of systemic IgM AL amyloidosis with underlying marginal zone lymphoma

Light chain amyloidosis (AL) is a rare disease caused by the generalized deposition of misfolded free light chains. Patients with immunoglobulin M gammopathy (IgM) and indolent B-cell lymphoma such as marginal zone lymphoma (MZL) may in some instances develop AL amyloidosis. So far, CAR T cells for AL amyloidosis have only been reported utilizing the B cell maturation antigen as target, while CD19 has so far not been used in AL amyloidosis.We report the case of a 71-year-old male, diagnosed with systemic AL kappa amyloidosis and MZL, receiving third-generation CAR T cell therapy targeting CD19. Prior treatment included bendamustine/rituximab and cyclophosphamide/ dexamethasone with subsequent autologous stem cell transplantation. CAR T application was well tolerated despite heart and kidney amyloid manifestations, and only early low-grade procedure-specific toxicities were observed. A continuous decrease in IgM, kappa light chains and kappa-to-lambda light chain difference was observed in the patient from day + 30 on, resulting in a deep hematological response six months after treatment.In summary, we present a novel case of CAR T cell treatment with third generation CD19 directed infusion for AL amyloidosis with an underlying secretory active B cell lymphoma, showing that this is an effective treatment modality and can be applied to patients with subsequent AL amyloidosis.

Birtamimab plus standard of care in light-chain amyloidosis: the phase 3 randomized placebo-controlled VITAL trial

Amyloid light-chain (AL) amyloidosis is a rare, typically fatal disease characterized by the accumulation of misfolded immunoglobulin light chains (LCs). Birtamimab is an investigational humanized monoclonal antibody designed to neutralize toxic LC aggregates and deplete insoluble organ-deposited amyloid via macrophage-induced phagocytosis. VITAL was a phase 3 randomized, double-blind, placebo-controlled clinical trial assessing the efficacy and safety of birtamimab + standard of care (SOC) in 260 newly diagnosed, treatment-naive patients with AL amyloidosis. Patients received 24 mg/kg IV birtamimab + SOC or placebo + SOC every 28 days. The primary composite end point was the time to all-cause mortality (ACM) or centrally adjudicated cardiac hospitalization ≥91 days after the first study drug infusion. The trial was terminated early after an interim futility analysis; there was no significant difference in the primary composite end point (hazard ratio [HR], 0.826; 95% confidence interval [CI], 0.574-1.189; log-rank P = .303). A post hoc analysis of patients with Mayo stage IV AL amyloidosis, those at the highest risk of early mortality, showed significant improvement in the time to ACM with birtamimab at month 9 (HR, 0.413; 95% CI, 0.191-0.895; log-rank P = .021). At month 9, 74% of patients with Mayo stage IV AL amyloidosis treated with birtamimab and 49% of those given placebo survived. Overall, the rates of treatment-emergent adverse events (TEAEs) and serious TEAEs were generally similar between treatment arms. A confirmatory phase 3 randomized, double-blind, placebo-controlled clinical trial of birtamimab in patients with Mayo stage IV AL amyloidosis (AFFIRM-AL; NCT04973137) is currently enrolling. The VITAL trial was registered at www.clinicaltrials.gov as #NCT02312206.

Light-chain cardiac amyloidosis for the non-expert: pearls and pitfalls

Cardiac amyloidosis (CA) is an uncommon, progressive, and fatal disease; the two main forms that can affect the heart are transthyretin CA and light chain CA (AL-CA). AL-CA is a medical urgency for which a diagnostic delay can be catastrophic for patients' outcome. In this manuscript, we focus on the pearls and pitfalls that are relevant to achieve a correct diagnosis and to avoid diagnostic and therapeutical delays. Through the aid of three unfortunate clinical cases, some fundamental diagnostic aspects are addressed, including the following: first, a negative bone scintigraphy does not exclude CA, with patients with AL-CA frequently showing no or mild cardiac uptake, and its execution should not delay hematological tests; second, fat pad biopsy does not have a 100% sensitivity for AL amyloidosis and, if negative, further investigations should be performed, particularly if the pre-test probability is high. Third, Congo Red staining is not sufficient to reach a definitive diagnosis and amyloid fibrils typing with mass spectrometry, immunohistochemistry, or immunoelectron microscopy is crucial. To achieve a timely and correct diagnosis, all the necessary investigations must be performed, always considering the yield and diagnostic accuracy of each examination.