Light-chain (AL) amyloidosis: diagnosis and treatment

Broken but not beaten: Challenge of reducing the amyloids pathogenicity by degradation

BACKGROUND

The accumulation of ordered protein aggregates, amyloid fibrils, accompanies various neurodegenerative diseases (such as Parkinson's, Huntington's, Alzheimer's, etc.) and causes a wide range of systemic and local amyloidoses (such as insulin, hemodialysis amyloidosis, etc.). Such pathologies are usually diagnosed when the disease is already irreversible and a large amount of amyloid plaques have accumulated. In recent years, new drugs aimed at reducing amyloid levels have been actively developed. However, although clinical trials have demonstrated a reduction in amyloid plaque size with these drugs, their effect on disease progression has been controversial and associated with significant side effects, the reasons of which are not fully understood.

AIM OF REVIEW

The purpose of this review is to summarize extensive array of data on the effect of exogenous and endogenous factors (physico-mechanical effects, chemical effects of low molecular weight compounds, macromolecules and their complexes) on the structure and pathogenicity of mature amyloids for proposing future directions of the development of effective and safe anti-amyloid therapeutics.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Our analysis show that destruction of amyloids is in most cases incomplete and degradation products often retain the properties of amyloids (including high and sometimes higher than fibrils, cytotoxicity), accelerate amyloidogenesis and promote the propagation of amyloids between cells. Probably, the appearance of protein aggregates, polymorphic in structure and properties (such as amorphous aggregates, fibril fragments, amyloid oligomers, etc.), formed because of uncontrolled degradation of amyloids, may be one of the reasons for the ambiguous effectiveness and serious side effects of the anti-amyloid drugs. This means that all medications that are supposed to be used both for degradation and slow down the fibrillogenesis must first be tested on mature fibrils: the mechanism of drug action and cytotoxic, seeding, and infectious activity of the degradation products must be analyzed.

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.

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.

Mapping cellular response to destabilized transthyretin reveals cell- and amyloidogenic protein-specific signatures

BACKGROUND

In ATTR amyloidosis, transthyretin (TTR) protein is secreted from the liver and deposited as toxic aggregates at downstream target tissues. Despite recent advancements in treatments for ATTR amyloidosis, the mechanisms underlying misfolded TTR-mediated cellular damage remain elusive.

METHODS

In an effort to define early events of TTR-associated stress, we exposed neuronal (SH-SY5Y) and cardiac (AC16) cells to wild-type and destabilized TTR variants (TTRV122I (p.V142I) and TTRL55P (p.L70P)) and performed transcriptional (RNAseq) and epigenetic (ATACseq) profiling. We subsequently compared TTR-responsive signatures to cells exposed to destabilized antibody light chain protein associated with AL amyloidosis as well as ER stressors (thapsigargin, heat shock).

RESULTS

In doing so, we observed overlapping, yet distinct cell type- and amyloidogenic protein-specific signatures, suggesting unique responses to each amyloidogenic variant. Moreover, we identified chromatin level changes in AC16 cells exposed to mutant TTR that resolved upon pre-incubation with kinetic stabilizer tafamidis.

CONCLUSIONS

Collectively, these data provide insight into the mechanisms underlying destabilized protein-mediated cellular damage and provide a robust resource representing cellular responses to aggregation-prone proteins and ER stress.

Need for Early Recognition of Amyloidosis in Cases of Unexplained Heart Failure: A Case Report

Amyloidosis is a plasma cell dyscrasia that leads to the excessive production and deposition of mutant protein fragments in various organs. Cardiac amyloidosis is often implicated in two main subtypes: transthyretin (ATTR) and light chain (AL). While both subtypes increase the risk of restrictive cardiomyopathy, cardiogenic shock, and arrhythmias, poorer outcomes are seen in those with cardiac infiltration secondary to AL amyloidosis. Prognosis depends on the timing of diagnosis and the extent of the disease burden prior to recognition and treatment. The following case report describes a young patient who was admitted to the intensive care unit (ICU) for concerns of decompensated heart failure of unknown etiology, later determined to be due to amyloidosis. We describe her clinical course prior to and during hospital admission, along with the proposed physiologic factors that may have contributed to her poor outcome.

Non-Perturbative Identification and Subtyping of Amyloidosis in Human Kidney Tissue with Raman Spectroscopy and Machine Learning

Amyloids are proteins with characteristic beta-sheet secondary structures that display fibrillary ultrastructural configurations. They can result in pathologic lesions when deposited in human organs. Various types of amyloid protein can be routinely identified in human tissue specimens by special stains, immunolabeling, and electron microscopy, and, for certain forms of amyloidosis, mass spectrometry is required. In this study, we applied Raman spectroscopy to identify immunoglobulin light chain and amyloid A amyloidosis in human renal tissue biopsies and compared the results with a normal kidney biopsy as a control case. Raman spectra of amyloid fibrils within unstained, frozen, human kidney tissue demonstrated changes in conformation of protein secondary structures. By using t-distributed stochastic neighbor embedding (t-SNE) and density-based spatial clustering of applications with noise (DBSCAN), Raman spectroscopic data were accurately classified with respect to each amyloid type and deposition site. To the best of our knowledge, this is the first time Raman spectroscopy has been used for amyloid characterization of ex vivo human kidney tissue samples. Our approach, using Raman spectroscopy with machine learning algorithms, shows the potential for the identification of amyloid in pathologic lesions.

A Rare Case of Gastrointestinal Amyloidosis Due to Monoclonal Gammopathy of Undetermined Significance

Amyloidosis of the gastrointestinal (GI) tract is caused by the deposition of fibrils made of serum proteins into extracellular spaces. It is an uncommon disease with a poor prognosis, requiring prompt diagnosis and treatment. Treatment for amyloid light chain (AL)-type amyloidosis involves supportive care as well as addressing any underlying plasma cell dyscrasias. We present the case of a 64-year-old female diagnosed with AL-type GI amyloidosis with associated monoclonal gammopathy of undetermined significance. Unfortunately, the treatment was initiated nine months after the initial presentation, and she died one month later. Awareness of GI amyloidosis may allow for faster diagnosis and treatment in future patients.

Machine Learning Approaches in Diagnosis, Prognosis and Treatment Selection of Cardiac Amyloidosis

Cardiac amyloidosis is an uncommon restrictive cardiomyopathy featuring an unregulated amyloid protein deposition that impairs organic function. Early cardiac amyloidosis diagnosis is generally delayed by indistinguishable clinical findings of more frequent hypertrophic diseases. Furthermore, amyloidosis is divided into various groups, according to a generally accepted taxonomy, based on the proteins that make up the amyloid deposits; a careful differentiation between the various forms of amyloidosis is necessary to undertake an adequate therapeutic treatment. Thus, cardiac amyloidosis is thought to be underdiagnosed, which delays necessary therapeutic procedures, diminishing quality of life and impairing clinical prognosis. The diagnostic work-up for cardiac amyloidosis begins with the identification of clinical features, electrocardiographic and imaging findings suggestive or compatible with cardiac amyloidosis, and often requires the histological demonstration of amyloid deposition. One approach to overcome the difficulty of an early diagnosis is the use of automated diagnostic algorithms. Machine learning enables the automatic extraction of salient information from “raw data” without the need for pre-processing methods based on the a priori knowledge of the human operator. This review attempts to assess the various diagnostic approaches and artificial intelligence computational techniques in the detection of cardiac amyloidosis.

Amyloidoma and Plasmacytoma Presented as a Solitary Lung Nodule in a Patient of Multiple Myeloma With AL-Amyloidosis: A Case Report and Review of Literature

Nodular amyloidoma in the lungs is a rare entity, also the occurrence of extramedullary plasmacytoma (EMP) in the lungs is rare. To have concomitant EMP and amyloidoma presented as a single lung mass is even rarer. There was only one similar case reported in the abstract form previously. Our case did not respond to many novel chemotherapy agents, suggesting that this combination of amyloidoma and plasmacytoma belonged to a poor prognosis entity, requiring different treatment modalities, such as early bone marrow transplantation or CART (chimeric antigen receptors T) therapy.

A comprehensive overview of AL amyloidosis disease characteristics accumulated over two decades at a single referral center in Korea

BACKGROUND

Characteristics of AL amyloidosis across Asia are not well-described in the literature. Thus, we overviewed the incidence and disease characteristics of AL amyloidosis in Korea.

METHODS

We collected medical records of 302 AL amyloidosis patients and compared survival outcomes by predominant treatment strategy and at four time points: 1995-2003, 2004-2008, 2009-2013, and 2014-2018.

RESULTS

The median age was 62 years (36-83). One hundred forty-one patients were classified as stage III (26.3%) or IV (47.9%). The patients diagnosed between 2014 and 2018 survived longer than those diagnosed at other time points due to the introduction of bortezomib (p < 0.01). In addition, patients who received upfront ASCT survived longer than those who received salvage ASCT or chemotherapy alone (p < 0.01). However, most of the 85 patients who experienced early death within 6 months were older than 75 years, had BMI less than 20, and had a high disease burden.

CONCLUSIONS

The incidence of AL amyloid has increased and survival outcomes have improved gradually, most likely due to introduction of novel agents and upfront ASCT. However, not all patients are suitable for these potent treatment modalities, and avoiding early death within 6 months remains a challenge.

Changing paradigm in the treatment of amyloidosis: From disease-modifying drugs to anti-fibril therapy

Cardiac amyloidosis is a rare, debilitating, and usually fatal disease increasingly recognized in clinical practice despite patients presenting with non-specific symptoms of cardiomyopathy. The current standard of care (SoC) focuses on preventing further amyloid formation and deposition, either with anti-plasma cell dyscrasia (anti-PCD) therapies in light-chain (AL) amyloidosis or stabilizers of transthyretin (TTR) in transthyretin amyloidosis (ATTR). The SoC is supplemented by therapies to treat the complications arising from organ dysfunction; for example, heart failure, arrhythmia, and proteinuria. Advancements in treatments have improved patient survival, especially for those whose disease is detected and for whom treatment is initiated at an early stage. However, there still are many unmet medical needs, particularly for patients with severe disease for whom morbidity and mortality remain high. There currently are no approved treatments to reverse amyloid infiltration and deplete the amyloid fibrils already deposited in organs, which can continue to cause progressive dysfunction. Anti-fibril therapies aimed at removing the deposited fibrils are being investigated for safety and efficacy in improving outcomes for patients with severe disease. However, there is no clinical evidence yet that removing deposited amyloid fibrils will improve organ function, thereby improving quality of life or extending life. Nevertheless, anti-fibril therapies are actively being investigated in clinical trials to evaluate their ability to complement and synergize with current SoC.

AL Amyloidosis for Cardiologists: Awareness, Diagnosis, and Future Prospects: JACC: CardioOncology State-of-the-Art Review

Amyloid light chain (AL) amyloidosis is a rare, debilitating, often fatal disease. Symptoms of cardiomyopathy are common presenting features, and patients often are referred to cardiologists. Cardiac amyloid infiltration is the leading predictor of death. However, the variable presentation and perceived rarity of the disease frequently lead to delay in suspecting amyloidosis as a cause of heart failure, leading to misdiagnoses and a marked delay in diagnosis, with devastating consequences for the patient. A median time from symptom onset to correct diagnosis of about 2 years is often too long when median survival from diagnosis for patients with AL amyloidosis and cardiomyopathy is 4 months to 2 years. The authors highlight the challenges to diagnosis, identify gaps in the current knowledge, and summarize novel treatments on the horizon to raise awareness about the critical need for early recognition of symptoms and diagnosis of AL amyloidosis aimed at accelerating treatment and improving outcomes for patients.

Isolated prostate amyloidosis; a case report

Identification of amyloidosis on a prostate biopsy specimen raises suspicion for systemic amyloidosis. For patients at risk of prostate adenocarcinoma, a transrectal MRI ultrasound fusion (MRI-TRUS) guided biopsy of the prostate is often needed for further investigation. Our patient is a 70 year old male presenting from his primary care provider with an elevated PSA. The patient underwent MRI-TRUS fusion biopsy of the prostate, which demonstrated AL (lambda)-type amyloidosis, confirmed by mass spectrometry in addition to prostatic adenocarcinoma. He was subsequently diagnosed with primary amyloidosis of the prostate without evidence of other amyloid deposition sites.

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Prostate biopsies rarely have unique pathology, such as amyloidosis in our case.

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Amyloidosis of the prostate should trigger systemic amyloidosis workup.

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Unusually, no further evidence of extraprostatic amyloid deposition was found.

Real-world treatment patterns, costs, and outcomes in patients with AL amyloidosis: analysis of the Optum EHR and commercial claims databases

BACKGROUND

This study characterised real-world treatment patterns, clinical outcomes, and cost-of-illness in patients with light-chain (AL) amyloidosis.

METHODS

Data were extracted from the US-based Optum® EHR and Clinformatics® Data Mart (claims) databases (2008-2019) for patients newly diagnosed with AL amyloidosis and who initiated anti-plasma cell therapies. Healthcare resource utilisation (HCRU) and related costs were compared across lines of therapy (LOT). Incidences of cardiac and renal failure were evaluated using the Kaplan-Meier method.

RESULTS

About 1347 patients (EHR, n = 776; claims, n = 571) were included. Median age was 68 years; 56.8% were male. At initial diagnosis, 33.1% and 15.1% of patients had cardiac and renal failure, respectively. Most patients received bortezomib-containing treatment in LOT1 (69%); bortezomib-cyclophosphamide-dexamethasone was most common (26%). HCRU was similar across LOTs. Mean per-patient-per-month and per-patient-per-LOT costs were $19,343 and $105,944 for LOT1, $19,183 and $95,793 for LOT2, and $16,611 and $128,446 for LOT3, respectively. Costs were primarily driven by anti-plasma cell therapies, outpatient visits, and hospitalisations. The 5-year cardiac and renal failure rates following initial diagnosis were 64.5% and 39.0%, respectively.

CONCLUSION

AL amyloidosis is associated with substantial costs and suboptimal outcomes, highlighting the need for new therapeutic approaches to prevent organ deterioration, and reduce disease burden.

Clinical characteristics and prognostic value of renal immune complex deposition in patients with light chain amyloidosis

Although patients with light chain amyloidosis (AL) may present with co-deposition of amyloid and immune complexes (ICs) in renal biopsies, data on clinical characteristics and prognostic value of renal IC deposition are limited. A total of 73 patients with AL amyloidosis who were newly diagnosed by renal biopsy in Xijing Hospital (Xi'an, China) were divided into two groups (IC and non-IC groups). As a result, renal IC deposition was found in 26% of patients. Patients with IC deposition were associated with more urinary protein excretion and lower serum albumin. Notably, patients in the non-IC group achieved higher hematological overall response rate (81.5% vs. 47.4%, p = 0.007) and ≥VGPR rate (75.9% vs. 39.8%, p = 0.004) compared with those in IC group. Renal response rate was also higher in the non-IC group (63% vs. 31.6%, p = 0.031). With the median follow-up time of 19 months, a significantly worse overall survival was observed in patients with the IC group as compared with those without renal IC deposition in the Kaplan-Meier analysis (p = 0.036). Further multivariate analysis demonstrated that renal immune complex deposition was associated with worse overall survival in patients with AL amyloidosis (HR 5.927, 95% CI 2.148-16.356, p = 0.001).

Systematic literature review of evidence in amyloid light-chain amyloidosis

Introduction: Treatment of amyloid light-chain (AL) amyloidosis, a rare disease with a <5-year lifespan, remains challenging. This systematic literature review (SLR) aimed to evaluate the current evidence base in AL amyloidosis. Methods: Literature searches on clinical, health-related quality of life, economic and resource use evidence were conducted using the Embase, MEDLINE and Cochrane databases as well as gray literature. Results: This SLR yielded 84 unique studies from: five randomized controlled trials; 54 observational studies; 12 health-related quality of life studies, none with utility values; no economic evaluation studies; and 16 resource use studies, none with indirect costs. Conclusion: This SLR highlights a paucity of published literature relating to randomized controlled trials, utility values, economic evaluations and indirect costs in AL amyloidosis.

Population Pharmacokinetics and Exposure-Response Modeling of Daratumumab Subcutaneous Administration in Patients With Light-Chain Amyloidosis

The purpose of this study is to characterize the population pharmacokinetics (popPK) of subcutaneous (SC) daratumumab in combination with bortezomib, cyclophosphamide, and dexamethasone and explore the relationship between daratumumab systemic exposure and selected efficacy and safety end points in patients with newly diagnosed systemic amyloid light-chain amyloidosis. The popPK analysis included pharmacokinetic and immunogenicity data from patients receiving daratumumab SC in combination with bortezomib, cyclophosphamide, and dexamethasone in the ANDROMEDA study (AMY3001; safety run-in, n = 28; randomized phase, n = 183). Nonlinear mixed-effects modeling was used to characterize the popPK and quantify the impact of potential covariates. The exposure-response (E-R) analysis included data from all patients in the randomized phase of ANDROMEDA (n = 388). Logistic regression and survival analysis were used to evaluate the relationships between daratumumab systemic exposure and efficacy end points. The E-R analysis on safety was conducted using quartile comparison and logistic regression analysis. The observed concentration-time data of daratumumab SC were well described by a 1-compartment popPK model with first-order absorption and parallel linear and nonlinear Michaelis-Menten elimination pathways. None of the investigated covariates were determined to be clinically meaningful. Daratumumab systemic exposure was generally similar across subgroups that achieved different levels of hematologic response, and there was no apparent relationship between daratumumab systemic exposure and the investigated safety end points. In conclusion, the popPK and E-R analyses supported the selected 1800-mg flat dose of daratumumab SC in combination with bortezomib, cyclophosphamide, and dexamethasone regimen for the treatment of light-chain amyloidosis. No dose adjustment was recommended for investigated covariates.

Clinical and Radiological Features of Intramuscular Orbital Amyloidosis: A Case Series and Literature Review

PURPOSE

Orbital amyloidosis of the extraocular muscles (EOMs) is a rare condition, and its clinicoradiological features are not well elucidated. This study describes the characteristic clinical signs, MRI features, and potential treatment options.

METHODS

Retrospective multicenter case series and literature review of EOM amyloidosis.

RESULTS

Five cases were identified for inclusion. Common clinical findings were diplopia, ophthalmoplegia, and proptosis. Systemic amyloidosis was more likely to present with multiple muscle involvement, but no particular pattern was observed with localized disease. On MRI, amyloid deposition was characterized as a heterogeneous intramuscular mass with T2 hypointensity and post contrast enhancement. Management is dependent on the extent of disease and functional impairment; options include surgical debulking and radiation therapy.

CONCLUSION

EOM amyloidosis is uncommon. The combination of clinical and radiologic findings described in this study should lead to its clinical suspicion.

Free Immunoglobulin Light Chains in Patients with Tick-Borne Encephalitis: Before and after Treatment

Background: Tick-borne encephalitis (TBE) is inflammation of the central nervous system (CNS) caused by a viral infection which may be associated with increased synthesis of immunoglobulins. It can lead to inter alia, breakdown of the blood-brain barrier (BBB), or even death and, unfortunately, treatment is only symptomatic. Therefore, the aim of the present study was assessment of the concentrations of free light chains (FLC) kappa (κ) and lambda (λ in the cerebrospinal fluid (CSF) and serum of patients with TBE. Methods: A total of 58 cerebrospinal fluid and serum sample pairs were analyzed. Samples were collected from patients with TBE before and after treatment. FLC were measured using the turbidimetric method. The values of κIgG-index, λIgG-index, κFLC-index and λFLC-index were calculated using relevant formulas. Results: Pre-treatment serum λFLC concentrations were higher in comparison to post-treatment levels. Moreover, it was observed that CSF λFLC, TBEV IgM, TBEV IgG, and serum TBEV IgG, as well as the values of λFLC-index, κFLC-index, and λIgG-index were elevated after treatment. In the total study group, the concentrations of CSF κFLC and λFLC, and values of four indexes: κFLC-index, λFLC-index, κIgG-index, and λIgG-index correlated with each other and with CSF TBEV IgM and IgG antibodies. The CSF level of TBEV IgG was also associated with serum IgG TBEV and CSF IgM TBEV antibodies. Additionally, serum κFLC correlated with serum and CSF λFLC. Conclusion: This is the first study that demonstrates statistically significant differences in serum and CSF λFLC, as well as in the calculated values of three algorithms: λIgG-index, κFLC-index, and λIgG-index prior to and following treatment of TBE. Our findings may indicate that these differences reflect the intrathecal synthesis of immunoglobulins and increased permeability of BBB in patients with TBE. Moreover, it could provide the basis for developing new therapeutic strategies.

Diagnosis of wild-type transthyretin amyloid cardiomyopathy in Japan: red-flag symptom clusters and diagnostic algorithm

Wild‐type transthyretin amyloid cardiomyopathy (ATTRwt‐CM) is caused by the deposition of wild‐type transthyretin (TTR) amyloid fibrils in the heart. The age at diagnosis of ATTRwt‐CM is reported to be approximately 70–80 years, and patients commonly present with non‐disease‐specific cardiac abnormalities, such as heart failure with preserved ejection fraction and diastolic dysfunction. The disease can be fatal if left untreated, with an approximate survival of 3–5 years from diagnosis. An oral TTR stabilizer, tafamidis, has enabled early intervention for the treatment of ATTRwt‐CM. However, awareness of ATTRwt‐CM remains low, and misdiagnosis and a delay in diagnosis are common. This review discusses the epidemiology, characteristics, treatment strategy, and red‐flag symptoms and signs of ATTRwt‐CM based on the published literature, as well as recent advances in diagnostic modalities that enable early and accurate diagnosis of the disease. We also discuss an algorithm for early and accurate diagnosis of ATTRwt‐CM in daily clinical practice. In our diagnostic algorithm, a suspected diagnosis of ATTRwt‐CM should be triggered by unexplained left ventricular hypertrophy (LVH), which is LVH that cannot be explained by an increased afterload due to hypertension or valvular disease. In addition, heart failure symptoms, laboratory test results (N‐terminal pro‐B‐type natriuretic peptide, high‐sensitivity troponin T, or high‐sensitivity troponin I), electrocardiogram and imaging (echocardiogram or cardiac magnetic resonance) data, age (≥60 years), and medical history suggestive of ATTRwt‐CM (e.g. carpal tunnel syndrome) should be examined. Detailed examinations using bone scintigraphy and monoclonal protein detection tests followed by tissue biopsy, amyloid typing, and TTR genetic testing are warranted for a definite diagnosis of ATTRwt‐CM.

Nuclear Imaging for the Diagnosis of Cardiac Amyloidosis in 2021

Cardiac amyloidosis is caused by the deposition of misfolded protein fibrils into the extracellular space of the heart. The diagnosis of cardiac amyloidosis remains challenging because of the heterogeneous manifestations of the disease. There are many different types of amyloidosis with light-chain (AL) amyloidosis and transthyretin (ATTR) amyloidosis being the most common types of cardiac amyloidosis. Endomyocardial biopsy is considered the gold standard for diagnosing cardiac amyloidosis and differentiating amyloid subtypes, but its use is limited because of the invasive nature of the procedure, with risks for complications and the need for specialized training and centers to perform the procedure. Radionuclide cardiac imaging has recently become the most commonly performed test for the diagnosis of ATTR amyloidosis but is of limited value for the diagnosis of AL amyloidosis. Positron emission tomography has been increasingly used for the diagnosis of cardiac amyloidosis and its applications are expected to expand in the future. Imaging protocols are under refinement to achieve better quantification of the disease burden and prediction of prognosis.

Predictors and outcomes of acute kidney injury during autologous stem cell transplantation in AL amyloidosis

BACKGROUND

Acute kidney injury (AKI) is a common complication after high dose melphalan and autologous stem cell transplantation (HDM/SCT) in patients with AL amyloidosis. However, its incidence, predictors and outcomes are not well known.

METHODS

This observational study included 223 patients with AL amyloidosis who underwent HDM/SCT. AKI was defined as an increase in serum creatinine to ≥ 1.5 times the baseline occurring within the first 30 days of HDM/SCT.

RESULTS

The median age was 58 years (range: 30-77). Kidney and cardiac involvement were present in 86.1% and 56.8%, respectively. The median eGFR was 83.5 mL/min/1.73m2 (range: 9-213) and proteinuria was 2,899 mg/24 h (range: 0-19,966). AKI occurred in 29.1% of patients. Dialysis was initiated in 15 patients (6.7%) and of these 12 (80%) were able to discontinue dialysis. Most of the episodes of AKI occurred within the first 2 weeks. With a median follow-up of 4.5 years (range: 0.1-16.5), AKI was associated with increased overall mortality, HR 4.53 (95%CI [2-10.23]). The 10-year overall survival (OS) was 87.1% without AKI, versus 56.9% with AKI. AKI was also associated with an increased risk for end stage kidney disease (ESKD), HR 4.6 (95%CI [1.44-14.38]). The risk of developing ESKD at 10-year was 18.9% with AKI, versus 8.1% without AKI. Several risk factors were found and using multivariate logistic regression, a prediction model was developed which included 3 readily available variables: eGFR<60 mL/min/1.73m2, IVSd>12mm, and albumin<3 g/dL. This model was able to predict AKI development with an AUC of 0.8.

CONCLUSIONS

AKI is common in the post-HDM/SCT period and it leads to increased risk for ESKD and death. Our prediction model is an easily deployable tool in clinical settings as part of the discussion with patients who are being prepared for HDM/SCT.

Recommendations for the diagnosis and management of transthyretin amyloidosis with gastrointestinal manifestations

Transthyretin amyloid (ATTR) amyloidosis is an adult-onset, rare systemic disorder characterized by the accumulation of misfolded fibrils in the body, including the peripheral nerves, the heart and the gastrointestinal tract. Gastrointestinal manifestations are common in hereditary (ATTRv) amyloidosis and are present even before the onset of the polyneuropathy in some cases. Delays in diagnosis of ATTRv amyloidosis with gastrointestinal manifestations commonly occur because of fragmented knowledge among gastroenterologists and general practitioners, as well as a shortage of centers of excellence and specialists dedicated to disease management. Although the disease is becoming well-recognized in the societies of Neurology and Cardiology, it is still unknown for most gastroenterologists. This review presents the recommendations for ATTRv amyloidosis with gastrointestinal manifestations elaborated by a working group of European gastroenterologists and neurologists, and aims to provide digestive health specialists with an overview of crucial aspects of ATTRv amyloidosis diagnosis to help facilitate rapid and accurate identification of the disease by focusing on disease presentation, misdiagnosis and management of gastrointestinal symptoms.

AL-amyloidosis with cardiac involvement. Diagnostic capabilities of non-invasive methods

There are presented the literature data and a description of the clinical course of the disease in isolated/predominant cardiac amyloidosis. Amyloid cardiomyopathy is the most common phenocopy of hypertrophic cardiomyopathy. The modern possibilities of non-invasive diagnostics using osteoscintigraphy for the differential diagnosis between amyloid cardiomyopathy caused by AL- and transthyretin amyloidosis are described in detail.

The Clone Wars: Diagnosing and Treating Dysproteinemic Kidney Disease in the Modern Era

Dysproteinemic kidney diseases are disorders that occur as the result of lymphoproliferative (B cell or plasma cell) disorders that cause kidney damage via production of nephrotoxic monoclonal immunoglobulins or their components. These monoclonal immunoglobulins have individual physiochemical characteristics that confer specific nephrotoxic properties. There has been increased recognition and revised characterization of these disorders in the last decade, and in some cases, there have been substantial advances in disease understanding and treatments, which has translated to improved patient outcomes. These disorders still present challenges to nephrologists and patients, since they are rare, and the field of hematology is rapidly changing with the introduction of novel testing and treatment strategies. In this review, we will discuss the clinical presentation, kidney biopsy features, hematologic characteristics and treatment of dysproteinemic kidney diseases.

Cardiac Amyloid for the Internist

Cardiac amyloid is an uncommon cause of diastolic dysfunction the recognition of which requires the internist to have clinical suspicion to guide diagnosis and treatment. Cardiac amyloid is an infiltrative cardiomyopathy with significant morbidity and mortality. Appropriate diagnosis is important because management of cardiac amyloid differs from typical heart failure with preserved ejection fraction. An astute internist must be able to recognize common findings of cardiac amyloidosis. Here we present a case of a patient presenting with diastolic heart failure and the steps leading towards diagnosis and subsequent treatment.

Localized Lymph Node Light Chain Amyloidosis

The prognosis of systemic amyloid light chain (AL) amyloidosis is generally poor, hence requiring chemotherapy or hematopoietic stem cell transplantation, while the prognosis of localized AL amyloidosis without an abnormal monoclonal immunoglobulin light chain is good. Localized AL amyloidosis has been previously reported to be observed in pulmonary, urinary tract, gastrointestinal, oropharyngeal, and laryngeal sites. However, only a few cases of localized lymph node AL amyloidosis have so far been reported. We herein present a case of localized lymph node AL amyloidosis that could possibly be misdiagnosed as systematic AL amyloidosis.

A study from The Mayo Clinic evaluated long-term outcomes of kidney transplantation in patients with immunoglobulin light chain amyloidosis

Longer survival using modern therapies has increased the number of patients with immunoglobulin light-chain amyloidosis receiving kidney transplantation. We evaluated 60 patients with immunoglobulin light chain amyloidosis who underwent kidney transplantation based on their hematologic response for outcomes of death, graft failure, and complications. Patient hematologic responses (light-chain in blood or urine) prior to kidney transplantation were three patients had no response, five had a partial response, six had a very good partial response, 37 had a complete response, and nine were treatment-naive patients (never treated for this disorder). After transplantation, seven of nine treatment-naive patients achieved a complete response. The median follow-up for the entire transplant cohort was 61 months. The estimated median overall survival from the time of kidney transplantation was 123 months for the entire group. Median overall survival was not reached for the very good partial response plus complete response groups, it was 47 months for no response plus partial response groups, and 117 months for the treatment-naive group (all significantly different). Median overall survival of very good partial response was 81 months, while the median was not reached in the complete response group (no significant difference). The time to amyloid recurrence was significantly longer in complete response compared to very good partial response (median 181 vs 81 months). Death-censored graft survival at one- and five-years was 98.3%, and 95.8%, respectively for all groups. Of the 60 patients, three had allograft failure, 19 died with a functioning graft, and 13 had an amyloid recurrence. Thus, outcomes after kidney transplant in patients with immunoglobulin light-chain amyloidosis seem acceptable if a very good partial response or complete response is achieved either before or after transplantation.

Towards a novel target therapy for renal diseases related to plasma cell dyscrasias: The example of AL amyloidosis

Immunoglobulin light chain amyloidosis is a rare systemic disease caused by monoclonal light chains (LCs) depositing in tissue as insoluble fibrils resulting in irreversible damage of vital organs. The mechanisms involved in aggregation and deposition of LCs are not fully understood, but CD138/38 plasma cells are undoubtedly involved in monoclonal LC production. We are reporting favorable effects on AL amyloidosis patients with renal involvement using the anti-CD38 monoclonal antibody Daratumumab. We speculate that research for the near future should be devoted to design similar therapeutic approaches for other diseases attributable to a plasma cell dyscrasia.

A Rare Case of Light Chain Amyloidosis of the Gastrointestinal Tract

A 65-year-old Hispanic female presented with a one-year history of anorexia, nausea, early satiety, epigastric discomfort, and a 20 kg weight loss. Computed tomography (CT) demonstrated heterogeneous liver parenchyma. Upper endoscopy revealed large, fungating, infiltrative mass at the lesser gastric curvature incisura, highly suspicious of gastric tumor; however, initial biopsy of the gastric mass was equivocal and an exploratory laparoscopy was performed. Repeated intraoperative biopsies of the gastric mass and of liver parenchyma demonstrated diffuse hyalinized stroma consistent with amyloid deposition, and a bone marrow biopsy confirmed the diagnosis of primary light chain (AL) amyloidosis.

Droxidopa as an effective treatment for refractory neurogenic orthostatic hypotension and reflex bradycardia in amyloid light-chain amyloidosis: a case report

BACKGROUND

Droxidopa is an oral treatment for the stepwise treatment of neurogenic orthostatic hypotension from autonomic dysfunction. It has been shown to be useful predominantly with neurogenic orthostatic hypotension secondary to Parkinson's disease, but only a few cases have documented its usefulness in patients with neurogenic orthostatic hypotension due to amyloidosis, which is often severe and refractory. In addition, only one source in the literature reports the concomitant use of midodrine and droxidopa for such patients. Finally, we argue that droxidopa seems to have a protective effect against episodes of reflex bradycardia, which is not previously reported.

CASE PRESENTATION

A 64-year-old white man was admitted for 1 year of worsening syncopal episodes, diarrhea, failure to thrive, heart failure, and neuropathy. Medical emergencies were called five times on the overhead hospital intercom over a 4-day period in the beginning of his admission due to severe hypotension and bradycardia. He was eventually diagnosed as having amyloid light-chain amyloidosis and myeloma. After starting droxidopa, both his systolic blood pressure and reflex bradycardia improved, and no more medical emergency events were called during the remaining 30 days of admission. He felt much better subjectively and was able to sit upright and engage in physical therapy.

CONCLUSIONS

We show that droxidopa is effective when used with midodrine to treat refractory neurogenic orthostatic hypotension in patients with amyloidosis. There are very few cases reporting the use of droxidopa in amyloidosis, with only one study that uses droxidopa and midodrine concomitantly. In addition, our patient's reflex bradycardia improved drastically after starting droxidopa, which we believe is mediated by increased systemic norepinephrine. There were no side effects to droxidopa, and the benefits lasted well beyond the reported duration of 1-2 weeks that was noted to be a limitation in some studies.

CD38 and Anti-CD38 Monoclonal Antibodies in AL Amyloidosis: Targeting Plasma Cells and beyond

Immunoglobulin light chain amyloidosis (AL amyloidosis) is a rare systemic disease characterized by monoclonal light chains (LCs) depositing in tissue as insoluble fibrils, causing irreversible tissue damage. The mechanisms involved in aggregation and deposition of LCs are not fully understood, but CD138/38 plasma cells (PCs) are undoubtedly involved in monoclonal LC production.CD38 is a pleiotropic molecule detectable on the surface of PCs and maintained during the neoplastic transformation in multiple myeloma (MM). CD38 is expressed on T, B and NK cell populations as well, though at a lower cell surface density. CD38 is an ideal target in the management of PC dyscrasia, including AL amyloidosis, and indeed anti-CD38 monoclonal antibodies (MoAbs) have promising therapeutic potential. Anti-CD38 MoAbs act both as PC-depleting agents and as modulators of the balance of the immune cells. These aspects, together with their interaction with Fc receptors (FcRs) and neonatal FcRs, are specifically addressed in this paper. Moreover, the initiallyavailable experiences with the anti-CD38 MoAb DARA in AL amyloidosis are reviewed.

Outcome of patients with severe AL amyloidosis and biopsy-proven renal involvement ineligible for bone marrow transplantation

INTRODUCTION

AL amyloidosis is caused by a clone of plasma cell. Due to the impact of the disease on patient survival, careful evaluation of organ involvement is essential and treatment should be tailored to single patient's risk.

AIM

We analyzed the clinical, laboratory and histological characteristics of 21 elderly patients (pts) (mean age 74.7 ± 7.97 years, range 55-81) with AL amyloidosis, including 17 patients (81%) with biopsy-proven renal involvement, who were ineligible for bone marrow transplantation, and evaluated the impact of renal impairment on survival.

RESULTS

Cardiac and renal involvement was found in 14 (67%) cases. Among the 17 patients with renal involvement, 12 had renal failure with proteinuria, and one showed isolated renal failure and vascular amyloid deposition. Hematological response occurred in 57.1% after first line therapy (75% after three cycles). In six of the patients with renal involvement, proteinuria decreased from 4.2 to 1.1 g/24 h (range 0.2-3 g/24 h), serum Creatinina (sCr) levels declined or stabilized. Severe renal failure at diagnosis was found to directly influence patient survival, while the Staging System for Renal Outcome in AL Amyloidosis did not associate with outcomes.

CONCLUSIONS

To the best of our knowledge this is the first case series in which the whole cohort of patients with urinary or functional abnormalities underwent a histological evaluation. None of the patients were eligible for bone marrow transplantation. Hematologic response was 57.1%, while renal response was much lower (35%). Of note, the Staging System did not completely apply to this peculiar setting of patients in whom renal involvement was not presumptive but biopsy-proven. More aggressive approaches may be needed in these patients to avoid the inexorable progression of the disease.

Amyloidoma of the Tongue: Case Report, Surgical Management, and Review of the Literature

PURPOSE

Localized amyloidosis of the tongue is a benign condition in which surgical management may be considered. The aim of the study was to review the current literature and report a case.

MATERIALS AND METHODS

We searched the PubMed database for all relevant articles reporting cases of localized tongue amyloidosis published between 1980 and February 2020. In addition, we updated 1 case diagnosed and treated in our department.

RESULTS

A 49-year-old male patient presented with an asymptomatic tongue nodule of the dorsum mimicking median rhomboid glossitis. The results of an incisional biopsy showed an amyloid on Congo red staining and positive findings for the κ light chain by immunohistochemical analysis. The findings of the systemic workup were negative. Therefore, a diagnosis of localized κ light-chain amyloidosis was made. The patient underwent a resection of the lesion, and no recurrence or progression was observed during a period of 18 months. The literature review showed 12 reports describing 21 patients (11 men, 52.3%) with localized tongue amyloidosis. The most common clinical presentation was nodular with a single lesion of the tongue dorsum (15 patients, 71.4%). All cases showed positive findings on Congo red staining. Immunohistochemical analysis findings were available for only 9 patients (42.8%) and showed light-chain amyloidosis. No case showed any systemic involvement or the development of systemic disease. Surgical excision was performed in 9 cases, with recurrence at the site of operation in 2 cases.

CONCLUSIONS

Localized amyloidosis of the tongue is a rare disease in which surgical excision may be therapeutic when a multidisciplinary evaluation does not show any systemic disease. We recommend an excision when the lesion is persistent or shows an enlargement or when discomfort is reported. In the case of any further local recurrence, resection may be repeated.

The utility of repeat kidney biopsy in systemic immunoglobulin light chain amyloidosis

Background: The diagnostic utility of repeat kidney biopsy in AL amyloidosis patients in complete (CR) or very good partial hematologic response (VGPR) but with renal organ relapse is not clear.Methods: We present eight patients with AL amyloidosis who had a repeat kidney biopsy performed.Results: AL amyloidosis was initially diagnosed by a kidney biopsy. All patients had a favorable response to treatment (CR/VGPR) and five of them also had initially a renal organ response. A repeat kidney biopsy was done due to gradual deterioration of kidney function and/or proteinuria while maintaining a hematologic response. Repeat kidney biopsies showed findings consistent with amyloid deposits in all patients. Seven patients had renal progression with four of them requiring dialysis initiation. Only one patient had a favorable renal outcome. This patient had subacute kidney injury with decreasing proteinuria and was found to have granulomatous interstitial nephritis in addition to amyloid deposits and responded well to steroid treatment with rapid improvement in renal function.Conclusions: In AL amyloidosis patients who achieve a favorable hematologic response to treatment (CR/VGPR) but subsequently develop worsening renal insufficiency or proteinuria, a repeat kidney biopsy should generally not be performed. Amyloid deposits persist in the kidneys even after successful hematologic treatment and it is impossible to differentiate between new versus old amyloid deposits, which makes performing a repeat kidney biopsy unnecessary in most cases. Demonstration of amyloid deposits on repeat kidney biopsy would not aid in the decision making regarding re-initiation of hematologic treatment. A kidney biopsy should be considered only in cases when a specific alternative diagnosis is suspected.

Generalized Acquired Cutis Laxa Associated with Monoclonal Gammopathy of Dermatological Significance

Background

Cutis laxa is a rare dermatosis that is inherited or acquired and clinically features loose, wrinkled, and redundant skin with decreased elasticity. This heterogeneous connective tissue disorder may be localized or generalized, with or without internal manifestations. Generalized cutis laxa often has a cephalocaudal progression and is attributed to inflammatory cutaneous eruptions, medications, and infections. Cutis laxa is also associated with several other conditions including rheumatoid arthritis, systemic lupus erythematosus, and plasma-cell dyscrasias. Case Presentation. We report an unusual case of a 35-year-old male with progression of generalized acquired cutis laxa and vasculitis that occurred over a period of one year. No cutaneous inflammatory eruption preceded or accompanied his decreased skin elasticity, and a biopsy of the skin showed elastolysis. His cutaneous manifestation led to systemic evaluation and an eventual diagnosis of smoldering multiple myeloma accompanied by aortitis and anemia. His myeloma and vasculitis were successfully treated with cyclophosphamide, bortezomib, and dexamethasone and high-dose prednisone, respectively, with no improvement to his cutis laxa.

Conclusions

The presence of monoclonal gammopathy is strongly associated with several dermatological entities such as acquired cutis laxa. We propose a new term for the dermatological manifestations caused by paraproteinemia: monoclonal gammopathy of dermatological significance, or MGODS, and stress the evaluation of an underlying gammopathy in the setting of certain dermatologic conditions, including scleromyxedema and amyloidosis. We present a case of a newly acquired cutis laxa secondary to plasma-cell dyscrasias that exemplifies MGODS, alongside a brief literature review, and underscore the clinical relevance of monoclonal gammopathies of dermatological significance.

Dual Monoclonal Antibody Therapy in Patients With Systemic AL Amyloidosis and Cardiac Involvement

BACKGROUND

Systemic AL amyloidosis (AL) is a rare disease in which clonal immunoglobulin light chains produced by monoclonal plasma cells circulate and misfold, resulting in direct toxicity and fibrillar deposition of amyloid in numerous tissues. Early mortality from cardiac damage remains high. As depth of organ response carries a prognostic significance, combining anti-plasma cell and anti-amyloid therapies might hold the key to achieving long lasting responses. We report a series of patients who received 2 monoclonal antibodies, anti-CD38 and anti-amyloid, simultaneously.

MATERIALS AND METHODS

We describe the characteristics and outcomes of 19 patients who received daratumumab (anti-CD38) on progression with front-line therapy for AL, 9 of whom were on concurrent dual monoclonal antibody treatment with daratumumab and NEOD001 (anti-amyloid), and also provide data on the schedule, safety, and tolerability of intravenous infusions of these monoclonal antibodies.

RESULTS

The 9 patients who received treatment with dual monoclonal antibodies achieved a high rate (100%) of hematologic response in a median of 33 days. There was no significant toxicity to dual monoclonal antibody therapy. Seven of the 8 met criteria for cardiac response, achieved in less than 3 months of combined therapy. Ten patients who received daratumumab alone also had high rates of hematologic and organ responses.

CONCLUSIONS

Monoclonal antibodies with distinctly different targets can be safely combined in patients with AL and cardiac involvement. Patients experienced high rates of hematologic and cardiac response with combined anti-CD38 and anti-amyloid monoclonal antibody therapies. Further study of this combined approach is warranted.

Cardiac amyloidosis: in search of the ideal diagnostic tool

BACKGROUND

Cardiac amyloidosis (CA) is due to amyloid deposition in the myocardium. Transthyretin (ATTR) and light-chain (AL) amyloidosis are the main types of CA. Here, we present the clinical and imaging findings in patients with CA and discuss the controversies with the aim of finding the ideal diagnostic tool.

METHODS

Ten patients suspected of having CA on the basis of electrocardiographic (ECG) and echocardiographic findings were evaluated via cardiovascular magnetic resonance imaging (CMR; 1.5 T) using cine, late gadolinium enhancement (LGE), T1, T2 mapping, and extracellular volume fraction. N‑terminal pro-B-type natriuretic peptide (NT-proBNP) levels were also assessed in all patients.

RESULTS

All ten patients had an echocardiogram suggestive of CA. The CMR study documented ventricular hypertrophy leading to small ventricular volumes, as assessed by echocardiography. Diffuse subendocardial LGE, supporting the diagnosis of CA, was identified in all except one patient, who had subepicardial LGE due to myocarditis that was verified by endomyocardial biopsy (EMB). Right ventricular (RV) involvement was identified in four of the ten patients, whose condition deteriorated rapidly over the next 6 months. The NT-proBNP levels were >332 pg/ml in all except two patients. Light-chain amyloidosis was identified via fat tissue biopsy in two patients and through renal biopsy in one patient. In two patients with positive technetium-99m, EMB confirmed the diagnosis of ATTR.

CONCLUSION

NT-proBNP may be a sensitive but nonspecific biomarker for assessing CA. However, CMR is the only imaging modality that can assess the pathophysiologic background of cardiac hypertrophy and the severity of CA, irrespective of NT-proBNP level.

A new era for understanding amyloid structures and disease

The aggregation of proteins into amyloid fibrils and their deposition into plaques and intracellular inclusions is the hallmark of amyloid disease. The accumulation and deposition of amyloid fibrils, collectively known as amyloidosis, is associated with many pathological conditions that can be associated with ageing, such as Alzheimer disease, Parkinson disease, type II diabetes and dialysis-related amyloidosis. However, elucidation of the atomic structure of amyloid fibrils formed from their intact protein precursors and how fibril formation relates to disease has remained elusive. Recent advances in structural biology techniques, including cryo-electron microscopy and solid-state NMR spectroscopy, have finally broken this impasse. The first near-atomic-resolution structures of amyloid fibrils formed in vitro, seeded from plaque material and analysed directly ex vivo are now available. The results reveal cross-β structures that are far more intricate than anticipated. Here, we describe these structures, highlighting their similarities and differences, and the basis for their toxicity. We discuss how amyloid structure may affect the ability of fibrils to spread to different sites in the cell and between organisms in a prion-like manner, along with their roles in disease. These molecular insights will aid in understanding the development and spread of amyloid diseases and are inspiring new strategies for therapeutic intervention.

A rare systemic etiology of heart failure and liver dysfunction

Systemic amyloidosis is a rare condition that can manifest with cardiomyopathy, hepatic dysfunction, and renal disease. Diagnosis is often missed and/or delayed due to chronic multi-system involvement and indeterminate signs and symptoms. Treatment generally involves systemic therapy and autologous stem-cell transplantation.