The systemic amyloidoses

Non-Val30Met mutation, septal hypertrophy, and cardiac denervation in patients with mutant transthyretin amyloidosis

Aims

Mutant transthyretin (ATTRm) amyloidosis is a systemic disease caused by the deposition of amyloid fibrils derived from mutated transthyretin. Although cardiac involvement impacts the prognosis of patients with ATTRm amyloidosis, the incidence of cardiac events, such as bradyarrhythmia, ventricular tachycardia, and heart failure, has not been fully elucidated. The aim of this study was to evaluate the prognosis and predictors of clinical outcomes, including cardiac events, in patients with ATTRm amyloidosis in Japan.

Methods and results

We evaluated 90 consecutive patients with ATTRm amyloidosis at Kumamoto University. ATTRm amyloidosis was diagnosed by the observation of both amyloid fibril deposition on tissue biopsy and a transthyretin mutation on sequential analysis. Sympathetic nerve activity was evaluated in 59 patients using 123‐iodine metaiodobenzylguanidine (¹²³I‐MIBG) imaging. The endpoint was a composite of all‐cause death, hospitalization for heart failure, and implantation of a pacemaker, implantable cardioverter defibrillator, or cardiac resynchronization therapy defibrillator. Sixty‐seven patients had the Val30Met mutation (74%). The composite endpoint occurred in 23 patients (26%): all‐cause death (n = 6), hospitalization for worsening heart failure (n = 1), and implantation of an implantable cardioverter defibrillator (n = 6), cardiac resynchronization therapy defibrillator (n = 3), or pacemaker (n = 7). The 5‐year incident rate for clinical outcomes was 19%. In a multivariate Cox hazard analysis, age [hazard ratio (HR): 1.07, 95% confidence interval (95% CI): 1.01–1.12, P = 0.015], PQ interval (HR: 1.01, 95% CI: 1.00–1.02, P = 0.042), interventricular septum thickness in diastole (HR: 1.25, 95% CI: 1.09–1.42, P = 0.001), and non‐Val30Met mutation (HR: 4.31, 95% CI: 1.53–12.16, P = 0.006) were independent predictive factors of clinical outcomes. Kaplan–Meier analysis demonstrated a significantly higher probability of the composite endpoint in the non‐Val30Met group than in the Val30Met group (log‐rank test: P = 0.002) and in patients with left ventricular hypertrophy than in patients without left ventricular hypertrophy (log‐rank test: P < 0.001). In patients who underwent ¹²³I‐MIBG imaging, a delayed heart‐to‐mediastinum (HM) ratio <1.6 was a significant predictive factor of the composite endpoint (HR: 4.98, 95% CI: 1.73–14.37, P = 0.003) in the univariate Cox hazard analyses. Kaplan–Meier curve analysis showed that a delayed HM ratio <1.6 was associated with a poor prognosis (log‐rank test: P = 0.001).

Conclusions

Non‐Val30Met mutation, septal hypertrophy, and a delayed HM ratio are useful predictors of clinical outcomes in patients with ATTRm amyloidosis in Japan. These results suggest that it is important to evaluate cardiac involvement in terms of morphological (left ventricular hypertrophy) and functional (cardiac denervation) perspectives using echocardiography and ¹²³I‐MIBG imaging, respectively.

Right ventricular involvement in transthyretin amyloidosis

BACKGROUND

The extent of right ventricular (RV) involvement in transthyretin amyloidosis (ATTR) is unknown.

OBJECTIVES

This study sought to establish the degree of RV involvement in ATTR amyloidosis, and compare findings with RV involvement in hypertrophic cardiomyopathy (HCM).

METHODS

Forty-two patients with ATTR amyloidosis and echocardiographic evidence of cardiac amyloidosis (cardiac ATTR), 19 ATTR patients with normal left ventricular (LV) wall thickness (non-cardiac ATTR), 25 patients with diagnosed HCM and 30 healthy controls were included in this study. Echocardiographic measurements for conventional parameters, as well as RV global and segmental strain, were recorded.

RESULTS

When comparing RV structure and function between cardiac ATTR amyloidosis and HCM patients, only segmental strain differed between the two groups. In cardiac ATTR amyloidosis, we found an RV apex-to-base strain gradient with highest deformation in the apex. This pattern was reversed in patients with HCM.

CONCLUSIONS

RV involvement is common in cardiac ATTR patients. The present study also detected an RV apical sparing pattern in patients with ATTR cardiomyopathy, similar to what has previously been described for the left ventricle in these patients. This pattern was not seen in HCM patients. Further studies are needed to assess the clinical importance of these findings.

Hereditary transthyretin amyloidosis: baseline characteristics of patients in the NEURO-TTR trial

BACKGROUND

Hereditary transthyretin (ATTRm) amyloidosis is a rare, progressive and fatal disease with a range of clinical manifestations.

OBJECTIVE

This study comprehensively evaluates disease characteristics in a large, diverse cohort of patients with ATTRm amyloidosis.

METHODS

Adult patients (N = 172) with Stage 1 or Stage 2 ATTRm amyloidosis who had polyneuropathy were screened and enrolled across 24 investigative sites and 10 countries in the NEURO-TTR trial ( www.clinicaltrials.gov , NCT01737398). Medical and disease history, quality of life, laboratory data, and clinical assessments were analyzed.

RESULTS

The NEURO-TTR patient population was diverse in age, disease severity, TTR mutation, and organ involvement. Twenty-seven different TTR mutations were present, with Val30Met being the most common (52%). One third of patients reported early onset disease (before age 50) and the average duration of neuropathy symptoms was 5.3 years. Symptoms affected multiple organs and systems, with nearly 70% of patients exhibiting broad involvement of weakness, sensory loss, and autonomic disturbance. Over 60% of patients had cardiomyopathy, with highest prevalence in the United States (72%) and lowest in South America/Australasia (33%). Cardiac biomarker NT-proBNP correlated with left ventricular wall thickness (p<.001). Quality of life, measured by Norfolk QoL-DN and SF-36 patient-reported questionnaires, was significantly impaired and correlated with disease severity.

CONCLUSIONS

Baseline data from the NEURO-TTR trial demonstrates ATTRm amyloidosis as a systemic disease with deficits in multiple organs and body systems, leading to decreased quality of life. We report concomitant presentation of polyneuropathy and cardiomyopathy in most patients, and early involvement of multiple body systems.

Recent advances in understanding and treating immunoglobulin light chain amyloidosis

Immunoglobulin (Ig) light chain (AL) amyloidosis is a clonal plasma cell disorder characterized by misfolded Ig light chain deposition in vital organs of the body, resulting in proteotoxicity and organ dysfunction. Owing to its diverse clinical presentations and a tendency to mimic common medical conditions, AL amyloidosis is often diagnosed late and results in dismal outcomes. Early referral to a specialized center with expertise in management of AL amyloidosis is always recommended. The availability of sensitive biomarkers and novel therapies is reforming our approach to how we manage AL amyloidosis. Treatment for patients with AL amyloidosis should be risk-adapted and customized on the basis of individual patient characteristics. In the future, approaches directed at amyloid fibril clearance in combination with agents that target plasma cells will be needed both to eradicate the malignant clone and to establish organ responses.

Development and validation of a TTR-specific copy number screening tool, and application to potentially relevant patient cohorts

TTR amyloidosis (ATTR) is a fatal condition caused by extracellular deposits of misfolded transthyretin. Patients often present with cardiac disease, but manifestations may also involve other organs including the peripheral nervous system. ATTR is considered familial when heterozygous mutations in the TTR gene are present (ATTRmutant or ATTRm), or acquired when no TTR aberrations are detected (ATTRwildtype or ATTRwt). We hypothesized that TTR copy number variants (CNVs), which would escape the standard diagnostic approaches, contribute to ATTR-related phenotypes, and developed a multiplex ligation-dependent probe amplification-based (MLPA-based), TTR-specific copy number screening tool. High inter-sample and intra-sample homogeneity of MLPA signals and the expected drop in signal intensity for restriction digest-based positive controls validated this tool. Subsequent application to 13 patients diagnosed with ATTRwt, and to 93 patients presenting with late onset and presumably inherited polyneuropathy did not identify TTR CNVs. We discuss insufficient sensitivity of the assay as well as non-existence and non-pathogenicity of TTR CNVs as potentially underlying our negative finding, but suggest size and composition of our cohorts as more likely explanations. Our CNV-screening tool will be made available to initiatives interested in screening additional and potentially more appropriate patient samples.

Enthalpy-Driven Stabilization of Transthyretin by AG10 Mimics a Naturally Occurring Genetic Variant That Protects from Transthyretin Amyloidosis

Transthyretin (TTR) amyloid cardiomyopathy (ATTR-CM) is a fatal disease with no available disease-modifying therapies. While pathogenic TTR mutations (TTRm) destabilize TTR tetramers, the T119M variant stabilizes TTRm and prevents disease. A comparison of potency for leading TTR stabilizers in clinic and structural features important for effective TTR stabilization is lacking. Here, we found that molecular interactions reflected in better binding enthalpy may be critical for development of TTR stabilizers with improved potency and selectivity. Our studies provide mechanistic insights into the unique binding mode of the TTR stabilizer, AG10, which could be attributed to mimicking the stabilizing T119M variant. Because of the lack of animal models for ATTR-CM, we developed an in vivo system in dogs which proved appropriate for assessing the pharmacokinetics-pharmacodynamics profile of TTR stabilizers. In addition to stabilizing TTR, we hypothesize that optimizing the binding enthalpy could have implications for designing therapeutic agents for other amyloid diseases.

Accelerated pre-senile systemic amyloidosis in PACAP knockout mice - a protective role of PACAP in age-related degenerative processes

Dysregulation of neuropeptides may play an important role in aging‐induced impairments. Among them, pituitary adenylate cyclase‐activating polypeptide (PACAP) is a potent cytoprotective peptide that provides an endogenous control against a variety of tissue‐damaging stimuli. We hypothesized that the progressive decline of PACAP throughout life and the well‐known general cytoprotective effects of PACAP lead to age‐related pathophysiological changes in PACAP deficiency, supported by the increased vulnerability to various stressors of animals partially or totally lacking PACAP. Using young and aging CD1 PACAP knockout (KO) and wild type (WT) mice, we demonstrated pre‐senile amyloidosis in young PACAP KO animals and showed that senile amyloidosis appeared accelerated, more generalized, more severe, and affected more individuals. Histopathology showed age‐related systemic amyloidosis with mainly kidney, spleen, liver, skin, thyroid, intestinal, tracheal, and esophageal involvement. Mass spectrometry‐based proteomic analysis, reconfirmed with immunohistochemistry, revealed that apolipoprotein‐AIV was the main amyloid protein in the deposits together with several accompanying proteins. Although the local amyloidogenic protein expression was disturbed in KO animals, no difference was found in laboratory lipid parameters, suggesting a complex pathway leading to increased age‐related degeneration with amyloid deposits in the absence of PACAP. In spite of no marked inflammatory histological changes or blood test parameters, we detected a disturbed cytokine profile that possibly creates a pro‐inflammatory milieu favoring amyloid deposition. In summary, here we describe accelerated systemic senile amyloidosis in PACAP gene‐deficient mice, which might indicate an early aging phenomenon in this mouse strain. Thus, PACAP KO mice could serve as a model of accelerated aging with human relevance. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Portal Hypertension and a Stiff Liver

Portal hypertension (PH) is a common clinical syndrome leading to severe complications. In the western world, about 90% of cases of PH are due to liver cirrhosis, and thanks to the availability of ultrasound elastography methods, this diagnosis is usually confirmed at bedside. We report a case of a patient presenting with PH and ascites initially suspected of suffering from liver cirrhosis. The finding of large hepatomegaly and a massive increase in liver stiffness prompted us to perform a liver biopsy. This revealed no fibrosis, but diffuse primary amyloidosis (AL amyloidosis). We discuss the diagnostic and treatment of this case, with emphasis on non-invasive imaging methods available for diagnosis and follow up.

MRI feature tracking strain is prognostic for all-cause mortality in AL amyloidosis

OBJECTIVES

Cardiac involvement is a major determinate of mortality in light chain (AL) amyloidosis. Cardiac magnetic resonance imaging (MRI) feature tracking (FT) strain is a new method for measuring myocardial strain. This study retrospectively evaluated the association of MRI FT strain with all-cause mortality in AL amyloidosis.

MATERIALS AND METHODS

Seventy-six patients with newly diagnosed AL amyloidosis underwent cardiac MRI. 75 had images suitable for MRI FT strain analysis. MRI delayed enhancement, morphologic and functional evaluation, cardiac biomarker staging and transthoracic echocardiography were also performed. Subjects' charts were reviewed for all-cause mortality. Cox proportional hazards analysis was used to evaluate survival in univariate and multivariate analysis.

RESULTS

There were 52 deaths. Median follow-up of surviving patients was 1.7 years. In univariate analysis, global radial (Hazard Ratio (HR) = 0.95, p <.01), circumferential (HR = 1.09, p < .01) and longitudinal (HR = 1.08, p < .01) strain were associated with all-cause mortality. In separate multivariate models, radial (HR = 0.96, p = .02), circumferential (HR = 1.09, p = .03) and longitudinal strain (HR = 1.07, p = .04) remained prognostic when combined with presence of biomarker stage 3.

CONCLUSIONS

MRI FT strain is associated with all-cause mortality in patients with AL amyloidosis.

Cardiac Structural and Functional Consequences of Amyloid Deposition by Cardiac Magnetic Resonance and Echocardiography and Their Prognostic Roles

OBJECTIVES

This cross-sectional study aimed to describe the functional and structural cardiac abnormalities that occur across a spectrum of cardiac amyloidosis burden and to identify the strongest cardiac functional and structural prognostic predictors in amyloidosis using cardiac magnetic resonance (CMR) and echocardiography.

BACKGROUND

Cardiac involvement in light chain and transthyretin amyloidosis is the main driver of prognosis and influences treatment strategies. Numerous measures of cardiac structure and function are assessed by multiple imaging modalities in amyloidosis.

METHODS

A total f 322 subjects (311 systemic amyloidosis and 11 transthyretin gene mutation carriers) underwent comprehensive CMR and transthoracic echocardiography. The probabilities of 11 commonly measured structural and functional cardiac parameters being abnormal with increasing cardiac amyloidosis burden were evaluated. Cardiac amyloidosis burden was quantified using CMR-derived extracellular volume. The prognostic capacities of these parameters to predict death in amyloidosis were assessed using Cox proportional hazards models.

RESULTS

Left ventricular mass and mitral annular plane systolic excursion by CMR along with strain and E/e' by echocardiography have high probabilities of being abnormal at low cardiac amyloid burden. Reductions in biventricular ejection fractions and elevations in biatrial areas occur at high burdens of infiltration. The probabilities of indexed stroke volume, myocardial contraction fraction, and tricuspid annular plane systolic excursion (TAPSE) being abnormal occur more gradually with increasing extracellular volume. Ninety patients (28%) died during a median follow-up of 22 months (interquartile range: 10 to 38 months). Univariable analysis showed that all imaging markers studied significantly predicted outcome. Multivariable analysis showed that TAPSE (hazard ratio: 1.46; 95% confidence interval: 1.16 to 1.85; p < 0.01) and indexed stroke volume (hazard ratio: 1.24; 95% confidence interval: 1.04 to 1.48; p < 0.05) by CMR were the only independent predictors of mortality.

CONCLUSIONS

Specific functional and structural abnormalities characterize different burdens of cardiac amyloid deposition. In a multimodality imaging assessment of a large cohort of amyloidosis patients, CMR-derived TAPSE and indexed stroke volume are the strongest prognostic cardiac functional markers.

Positive Effectiveness of Tafamidis in Delaying Disease Progression in Transthyretin Familial Amyloid Polyneuropathy up to 2 Years: An Analysis from the Transthyretin Amyloidosis Outcomes Survey (THAOS)

INTRODUCTION

The effectiveness of tafamidis for the treatment of transthyretin familial amyloid polyneuropathy (TTR-FAP) was evaluated using data from the Transthyretin Amyloidosis Outcomes Survey (THAOS) registry.

METHODS

Subjects receiving tafamidis (n = 252) were compared with untreated subjects in a non-randomized, matched cohort analysis. Subjects were matched with up to four untreated controls by genetic mutation, region of birth, and mean treatment propensity score.

RESULTS

The matched, treated sample consisted predominantly of subjects with the Val30Met genotype (92.5%), from Portugal, and with a mean age of 40.4 years. Over the course of the 2-year follow-up period, subjects treated with tafamidis showed significantly less deterioration on the Neuropathy Impairment Score for Lower Limbs (p < 0.001) and its subscales (p < 0.023) compared with untreated subjects. There was significantly less deterioration among tafamidis-treated subjects compared with untreated subjects on the Norfolk Quality of Life scale (p < 0.001). There were no significant differences observed in functional (assessed by Karnofsky Performance Status Scale score) or nutritional (assessed by modified body mass index) status between the treated and untreated groups. The primary model which examined survival from baseline using the matched cohort was not able to yield estimates of the hazard ratio, as there were no deaths in the tafamidis-treated subjects.

CONCLUSION

These findings support the results from clinical trials and strengthen evidence of the effectiveness of tafamidis beyond conventional clinical trials.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00628745 FUNDING: Pfizer.

Right ventricular longitudinal strain: a tool for diagnosis and prognosis in light-chain amyloidosis

OBJECTIVES

Light-chain (AL) amyloidosis can lead to an infiltrative cardiomyopathy with increased wall thickness (IWT) of very poor prognosis. Our primary aim was to analyse the right ventricle (RV) in patients with IWT to discriminate AL amyloidosis from IWT due to hypertrophic cardiomyopathy (HCM) or to arterial hypertension (HTN). Our secondary aim was to assess if RV dysfunction predicts overall mortality in cardiac AL amyloidosis.

METHODS

We retrospectively and consecutively compared clinical, biological and echocardiographic data of 315 patients with IWT: 105 biopsy-proven AL amyloidosis patients, 105 patients with HCM and 105 patients with HTN. The prognostic value of these parameters was analysed in the AL amyloidosis group.

RESULTS

Free-wall right ventricular longitudinal strain (FWRVLS) worse than -21.2% discriminates AL amyloidosis [area under the curve (AUC) = 0.744)] from patients with IWT due to other aetiologies. In AL amyloidosis, FWRVLS is the strongest echocardiographic prognostic marker with AUC =0.722 and -16.5% as the optimal cut-off value, beyond which overall mortality increases significantly. It is also the only independent echocardiographic predictor of overall mortality (HR =1.113; 95%CI 1.029-1.204; p = .007), even when adjusted to the Mayo stage and global left ventricular longitudinal strain.

CONCLUSIONS

FWRVLS should be considered in the diagnostic and prognostic workup in light-chain amyloidosis.

Gastrointestinal perforation in light chain amyloidosis in the era of novel agent therapy - a case series and review of the literature

Gastrointestinal (GI) perforation is remarkably rare in patients with light chain (AL) amyloidosis and has not yet been reported in patients with AL amyloidosis treated with novel agents. Only 24 cases of GI perforation have previously been reported in the setting of AL amyloidosis of which 15 had available information in English. All 15 did not receive novel agent therapy and six died early after experiencing GI perforation. This study reports the characteristics and outcome of AL patients that developed GI perforation in the era of novel agent treatment. Seven patients were reviewed. In two patients, GI perforation was the presenting symptom of AL amyloidosis, whereas five patients developed GI perforations following initiation of an anti-AL therapy (three after bortezomib-based, 1 after lenalidomide-based and 1 after thalidomide-based therapy). All patients underwent surgery and survived the perforation. Treatment was renewed following surgery in six of seven patients, with no further GI complications. In conclusion, GI perforation in AL amyloidosis is rare and mostly reported after treatment initiation. Urgent surgery appears to be lifesaving and renewal of the anti-AL novel therapy appears to be safe, with no significant risk for re-perforation or GI toxicity. Prognosis in these patients is related to severity of the disease and response to therapy rather than the development of GI perforation.

Incidence of venous thromboembolism and use of anticoagulation in hematological malignancies: Critical review of the literature

Venous Thromboembolism (VTE) frequently complicates the course of hematologic malignancies (HM) and its incidence is similar to that observed in high-risk solid tumors. Despite that, pharmacologic prophylaxis and treatment of VTE in patients with HM is challenging, mainly because a severe thrombocytopenia frequently complicates the course of treatments or may be present since diagnosis, thus increasing the risk of bleeding. Therefore, in this setting, safe and effective methods of VTE prophylaxis and treatment have not been well defined and hematologists generally refer to guidelines produced for cancer patients that give indications on anticoagulation in patients with thrombocytopenia. In this review, besides to summarize the incidence and the available data on prophylaxis and treatment of VTE in HM, we give some advices on how to use antithrombotic drugs in patients with HM according to platelets count.

Oligosecretory Myeloma With Amyloidosis and Alopecia

Amyloidosis is a systemic illness characterized by the extracellular deposition of abnormal proteins in body tissues and organs. In addition to renal involvement, amyloidosis can also present with a variety of skin manifestations, though rarely with alopecia. Sixteen cases of alopecia secondary to systemic amyloidosis are reported. There is one reported case that presented with alopecia universalis. We report a case of a 68-year-old woman presenting with alopecia universalis, rapid decline in kidney function, and nephrotic syndrome who was found to have multiple myeloma-associated AL amyloidosis (immunoglobulin light chain). Her serological workup including serum electrophoresis was negative and she underwent renal biopsy. Pathology revealed eosinophilic material within the mesangium that was Congo-red positive, had apple-green birefringence under polarized light, and ultramicroscopically appeared as fibrillary material. Subsequent bone marrow examination showed a diffuse increase in plasma cells with atypia indicating plasma cell neoplasm. This case underlines several interesting aspects of multiple myeloma and the way it may present with amyloidosis. The lack of monoclonal spike on electrophoresis yet positive light chain analysis deserves special attention by clinicians to avoid a missed diagnosis. The extensive skin involvement also raises several questions regarding the pathologic mechanisms of alopecia in a patient with amyloidosis.

Atraumatic Splenic Rupture Due to Ectopic Extramedullary Hematopoiesis after Autologous Stem Cell Transplantation in a Patient with AL Amyloidosis

A 50-year-old man was diagnosed with multiple myeloma complicating AL amyloidosis. Splenic rupture was complicated during autologous stem cell transplantation (auto-SCT). Granulocyte colony-stimulating factor (G-CSF) was not administered. A pathological examination of the spleen revealed that CD34-positive cells were concentrated in the ruptured part of the splenic capsule. Hematopoietic cells were engrafted in the small gap between the capsule and amyloid protein deposition area of the spleen, which might have caused the splenic rupture in the absence of G-CSF administration. Special attention is thus required for amyloidosis patients undergoing auto-SCT, even when G-CSF is not administered.

Nationwide Survey of 741 Patients with Systemic Amyloid Light-chain Amyloidosis in Japan

Objective To retrospectively investigate the clinical manifestations of systemic amyloid light-chain (AL) amyloidosis in Japanese patients and the treatment strategy for the condition. Methods We conducted a survey of Japanese AL amyloidosis patients, who were treated between January 1, 2012, and December 31, 2014. Results A total of 741 AL amyloidosis patients were included in this study (436 men and 305 women; median age: 65 years old, range: 31-93). The most frequently affected organ was the kidneys (n=542), followed by the heart (n=252), gastrointestinal (GI) tract (n=164), autonomic nervous system (n=131), liver (n=71), and peripheral nervous system (n=71). Diagnostic findings were most commonly detected in the GI tract (upper GI tract: 350 cases, lower GI tract: 167 cases), followed by the bone marrow and kidneys. An abdominal fat-pad biopsy was only conducted in 128 patients. Autologous stem cell transplants (ASCTs) and bortezomib were used to treat 126 and 276 patients, respectively. Conclusion The clinical features of Japanese patients with systemic AL amyloidosis are similar to those reported previously for cases in the US and Europe. Regarding treatment, a significant number of ASCTs were performed in Japan as well as in Western countries. Surprisingly, a marked number of patients received bortezomib as a treatment for AL amyloidosis.

The prognostic value of T1 mapping and late gadolinium enhancement cardiovascular magnetic resonance imaging in patients with light chain amyloidosis

BACKGROUND

Cardiac impairment is associated with high morbidity and mortality in immunoglobulin light chain (AL) type amyloidosis, for which early identification and risk stratification is vital. For myocardial tissue characterization, late gadolinium enhancement (LGE) is a classic and most commonly performed cardiovascular magnetic resonance (CMR) parameter. T1 mapping with native T1 and extracellular volume (ECV) are recently developed quantitative parameters. We aimed to investigate the prognostic value of native T1, ECV and LGE in patients with AL amyloidosis.

METHODS

Eighty-two patients (55.5 ± 8.5 years; 52 M) and 20 healthy subjects (53.2 ± 11.7 years; 10 M) were prospectively recruited. All subjects underwent CMR with LGE imaging and T1 mapping using a Modified Look-Locker Inversion-recovery (MOLLI) sequence on a 3 T scanner. Native T1 and ECV were measured semi-automatically using a dedicated CMR software. The left ventricular (LV) LGE pattern was classified as none, patchy, and global groups. Global LGE was considered when there was diffuse, transmural LGE in more than half of the short axis images. Follow-up was performed for all-cause mortality using Cox proportional hazards regression analysis and Kaplan-Meier survival curves.

RESULTS

The patients demonstrated an increase in native T1 (1438 ± 120 ms vs. 1283 ± 46 ms, P = 0.001) and ECV (43.9 ± 10.9% vs. 27.0 ± 1.7%, P = 0.001) compared to healthy controls. Native T1, ECV and LGE showed significant correlation with Mayo Stage, and ECV and LGE showed significant correlation with echocardiographic E/E' and LV ejection fraction. During the follow-up for a median time of 8 months, 21 deaths occurred. ECV ≥ 44.0% (hazard ratio [HR] 7.249, 95% confidence interval (CI) 1.751-13.179, P = 0.002) and global LGE (HR 4.804, 95% CI 1.971-12.926, P = 0.001) were independently prognostic for mortality over other clinical and imaging parameters. In subgroups with the same LGE pattern, ECV ≥ 44.0% remained prognostic (log rank P = 0.029). Median native T1 (1456 ms) was not prognostic for mortality (Tarone-Ware, P = 0.069).

CONCLUSIONS

During a short-term follow-up, both ECV and LGE are independently prognostic for mortality in AL amyloidosis. In patients with a similar LGE pattern, ECV remained prognostic. Native T1 was not found to be a prognostic factor.

A Filter Retardation Assay Facilitates the Detection and Quantification of Heat-Stable, Amyloidogenic Mutant Huntingtin Aggregates in Complex Biosamples

N-terminal mutant huntingtin (mHTT) fragments with pathogenic polyglutamine (polyQ) tracts spontaneously form stable, amyloidogenic protein aggregates with a fibrillar morphology. Such structures are detectable in brains of Huntington's disease (HD) patients and various model organisms, suggesting that they play a critical role in pathogenesis. Heat-stable, fibrillar mHTT aggregates can be detected and quantified in cells and tissues using a denaturing filter retardation assay (FRA). Here, we describe step-by-step protocols and experimental procedures for the investigation of mHTT aggregates in complex biosamples using FRAs. The methods are illustrated with examples from studies in cellular, transgenic fly, and mouse models of HD, but can be adapted for any disease-relevant protein with amyloidogenic polyQ tracts.

Rapid clinical improvement of amyloid A amyloidosis following treatment with tocilizumab despite persisting amyloid deposition: a case report

Background

Amyloid A amyloidosis is one of the most common forms of amyloidosis. It is secondary to rheumatoid arthritis, which is difficult to manage and has a poor prognosis. We present a patient with rheumatoid arthritis and amyloid A amyloidosis who was treated with tocilizumab, a humanized monoclonal antibody against interleukin 6 receptor, resulting in improvement in both proteinuria and gastrointestinal symptoms; however, amyloid deposition remained.

Case presentation

A 67-year-old woman who had previously been treated for rheumatoid arthritis presented with abdominal pain and diarrhea. Right renal cell carcinoma was found, and amyloid A amyloidosis was diagnosed concomitantly based on colon biopsy. The renal cell carcinoma was resected, and the non-cancerous part of the renal tissue also showed amyloid A deposition. Following surgery, protein levels in the urine increased to the nephrotic range, and administration of tocilizumab was initiated, which resulted in resolution of the proteinuria. The patient’s gastrointestinal symptoms were also alleviated. However, repeat colon biopsy showed amyloid deposition.

Conclusions

This case of amyloid A amyloidosis suggests that amyloid deposition indicates only structural change of the affected tissue, and that it is not amyloid deposition per se that causes the clinical symptoms of amyloidosis.

Imaging of Left Ventricular Hypertrophy: a Practical Utility for Differential Diagnosis and Assessment of Disease Severity

PURPOSE OF REVIEW

Left ventricular hypertrophy (LVH) is often encountered in clinical practice, and it is a risk factor for cardiac mortality and morbidity. Determination of the etiology and disease severity is important for the management of patients with LVH. The aim of this review is to show the remarkable progress in cardiac imaging and its importance in clinical practice.

RECENT FINDINGS

This review focuses on clinical features and characteristic cardiac imaging in LVH caused by various diseases including hypertension, aortic valve stenosis, hypertrophic cardiomyopathy, and secondary cardiomyopathies. The usefulness of echocardiography as a tool of general versatility including hemodynamic evaluation and the usefulness of cardiac magnetic resonance imaging for assessment of cardiac morphology and myocardial tissue characteristics of relevance for LVH are described. Imaging modalities now have central roles in the differentiation and prognostic assessment of LVH.

Amyloid-β peptide protects against microbial infection in mouse and worm models of Alzheimer's disease

The amyloid-β peptide (Aβ) is a key protein in Alzheimer's disease (AD) pathology. We previously reported in vitro evidence suggesting that Aβ is an antimicrobial peptide. We present in vivo data showing that Aβ expression protects against fungal and bacterial infections in mouse, nematode, and cell culture models of AD. We show that Aβ oligomerization, a behavior traditionally viewed as intrinsically pathological, may be necessary for the antimicrobial activities of the peptide. Collectively, our data are consistent with a model in which soluble Aβ oligomers first bind to microbial cell wall carbohydrates via a heparin-binding domain. Developing protofibrils inhibited pathogen adhesion to host cells. Propagating β-amyloid fibrils mediate agglutination and eventual entrapment of unatttached microbes. Consistent with our model, Salmonella Typhimurium bacterial infection of the brains of transgenic 5XFAD mice resulted in rapid seeding and accelerated β-amyloid deposition, which closely colocalized with the invading bacteria. Our findings raise the intriguing possibility that β-amyloid may play a protective role in innate immunity and infectious or sterile inflammatory stimuli may drive amyloidosis. These data suggest a dual protective/damaging role for Aβ, as has been described for other antimicrobial peptides.

Prognostic impact of immunoparesis at diagnosis and after treatment onset in patients with light-chain amyloidosis

OBJECTIVES

Immunoparesis (IP) is a risk factor associated with an unfavourable outcome in several plasma cell disorders. It has been suggested that its presence in light-chain (AL) amyloidosis could be associated with worse prognosis. However, the relevance of IP after treatment has not been evaluated to date. The aim of this study was to determine the prognostic impact of IP at diagnosis and one year after treatment onset in patients with AL amyloidosis.

METHODS

The clinical records of 69 patients with AL amyloidosis treated at a single institution from January 2006 to January 2016 were included in the study.

RESULTS

IP was observed in 27.5% of patients at diagnosis. The presence of IP was associated with a lower probability to achieve very good partial response or better after first-line treatment (37.8% versus 62.2%; p = .04). However, only in the group of patients treated with autologous stem cell transplantation (ASCT), the presence of IP resulted in a shorter progression-free survival (PFS) (30.2 months versus not reached [NR]; p = .02) but not in overall survival (OS). Persistence of IP at one year after treatment onset was identified in only four (9.8%) of the 41 evaluable patients. In the ASCT group, the absence of IP at one year after treatment onset resulted in a longer median PFS and OS (NR versus 22.6 months; p = .006; and NR versus 35.2 months; p < .001; respectively). In the multivariate analysis, the absence of IP at one year after treatment onset was independently associated with longer survival.

CONCLUSION

IP at diagnosis has a negative impact on survival while its absence at one year after treatment is an independent marker for long-term survival.

Extracellular volume with bolus-only technique in amyloidosis patients: Diagnostic accuracy, correlation with other clinical cardiac measures, and ability to track changes in amyloid load over time

BACKGROUND

Extracellular volume (ECV) by T₁ mapping requires the contrast agent distribution to be at equilibrium. This can be achieved either definitively with a primed contrast infusion (infusion ECV), or sufficiently with a delay postbolus (bolus-only ECV). For large ECV, the bolus-only approach measures higher than the infusion ECV, causing some uncertainty in diseases such as amyloidosis.

PURPOSE

To characterize the relationship between the bolus-only and current gold-standard infusion ECV in patients with amyloidosis.

STUDY TYPE

Bolus-only and infusion ECV were prospectively measured.

POPULATION

In all, 186 subjects with systemic amyloidosis attending our clinic and 23 subjects with systemic amyloidosis who were participating in an open-label, two-part, dose-escalation, phase 1 trial.

FIELD STRENGTH

Avanto 1.5T, Siemens Medical Solutions, Erlangen, Germany.

ASSESSMENT

Bolus-only and infusion ECV were measured in all subjects using shortened modified Look-Locker inversion recovery (ShMOLLI) T₁ mapping sequence.

STATISTICAL TESTS

Pearson correlation coefficient (r); Bland-Altman; receiver operating characteristic (ROC) curve analysis. Linear regression model with a fractional polynomial transformation.

RESULTS

The difference between the bolus-only and infusion myocardial ECV increased as the average of the two measures increased, with the bolus-ECV measuring higher. For an average ECV of 0.4, the difference was 0.013. The 95% limits of agreement for the two methods, after adjustment for the bias, were ±0.056. However, cardiac diagnostic accuracy was comparable (bolus-only vs. infusion ECV area under the curve [AUC] = 0.839 vs. 0.836), as were correlations with other clinical cardiac measures, and, in the trial patients, the ability to track changes in the liver/spleen with therapy.

DATA CONCLUSION

In amyloidosis, with large ECVs, the bolus-only technique reads higher than the infusion technique, but clinical performance by any measure is the same. Given the work-flow advantages, these data suggest that the bolus-only approach might be acceptable for amyloidosis, and might support its use as a surrogate endpoint in future clinical trials.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;47:1677-1684.

Abnormal Coronary Flow Velocity Reserve and Decreased Myocardial Contractile Reserve Are Main Factors in Relation to Physical Exercise Capacity in Cardiac Amyloidosis

BACKGROUND

The aim of the present study was to evaluate the clinical importance of echocardiographic coronary flow velocity reserve (CFVR), resting and exercise left ventricular global longitudinal strain (LVGLS), and myocardial work efficiency (MWE) in patients with cardiac amyloidosis (CA).

METHODS

The study population comprised 69 subjects: group A, 27 patients with CA confirmed by endomyocardial biopsy (CA positive); group B, 42 healthy control subjects. The amyloid phenotype in group A was as follows: patients with wild-type transthyretin-related amyloidosis (n = 10), carriers of the Danish familial transthyretin amyloidosis mutation with cardiac involvement (n = 5), and patients with amyloid light chain amyloidosis with cardiac involvement (n = 12). All subjects underwent comprehensive echocardiographic evaluation during rest and during symptom-limited, semisupine exercise testing. Furthermore, CFVR was assessed using Doppler echocardiography.

RESULTS

Patients with CA had significantly lower CFVR (1.7 ± 0.6 vs 3.9 ± 0.8, P < .0001), MWE (1.9 ± 1.0 vs 3.0 ± 0.7, P < .0001), and LVGLS magnitude (11% [10%-14%] vs 20% [18%-21%], P < .0001) than control subjects. Patients with CA showed severely reduced deformation and efficiency reserve compared with control subjects (ΔLVGLS 0.9 ± 2.8% vs 5.6 ± 2.3%, P < .0001; ΔMWE 2.5 ± 2.8 vs 8.8 ± 2.6, P < .0001). In patients with CA, a strong relation was seen between physical capacity by the metabolic equivalent of tasks test and CFVR (r = 0.55, P < .01), peak exercise LVGLS (r = 0.64, P < .0001), and peak exercise MWE (r = 0.60, P < .01).

CONCLUSIONS

Patients with CA had a profound lack of CFVR and longitudinal myocardial deformation reserve compared with healthy control subjects. Both parameters were significantly associated with exercise capacity and may prove useful for evaluating cardiac performance in patients with CA.

Prognostic and Added Value of Two-Dimensional Global Longitudinal Strain for Prediction of Survival in Patients with Light Chain Amyloidosis Undergoing Autologous Hematopoietic Cell Transplantation

BACKGROUND

Autologous hematopoietic cell transplantation (HCT) is a first-line therapy for prolonging survival in patients with light-chain (AL) amyloidosis. Cardiac involvement is the most important determinant of survival. However, patients with advanced cardiac involvement have often been excluded from HCT because of high risk for transplantation-related mortality and poor overall survival. Whether baseline left ventricular global longitudinal strain (GLS) can provide additional risk stratification and predict survival after HCT in this high-risk population remains unclear. The aim of this study was to evaluate the prognostic implication of baseline GLS and the added value of GLS beyond circulating cardiac biomarkers for risk stratification in patients with AL amyloidosis undergoing HCT.

METHODS

Eighty-two patients with newly diagnosed AL amyloidosis who underwent upfront HCT between January 2007 and April 2014 were included in the study. Clinical, echocardiographic, and serum cardiac biomarker data were collected at baseline and 12 months following HCT. GLS measurements were performed using a vendor-independent offline system. The median follow-up time for survivors was 58 months.

RESULTS

Sixty-four percent of patients were in biomarker-based Mayo stage II or III. GLS, brain natriuretic peptide, troponin, and mitral E/A ratio were identified as the strongest predictors of survival (P < .0001). Other predictors included sex, creatinine, free AL, wall thickness, and ejection fraction. Mayo stage was significantly associated with outcome, with 5-year survival of 93%, 72% and 31% in stage I, II, and III patients, respectively. GLS of 17% was identified as the value that best discriminated survivors from nonsurvivors, and the application of this cutoff value provided further mortality risk stratification within each Mayo stage.

CONCLUSIONS

GLS is a strong predictor of survival in patients with AL amyloidosis undergoing HCT, potentially providing incremental value over serum cardiac biomarkers for risk stratification. GLS should be considered as a standard parameter along with serum cardiac biomarkers when evaluating eligibility for HCT or other investigational therapies.

Nodular pulmonary amyloidosis: a complex disease with malignancy association

Pulmonary amyloidosis is a rare disease that incorporates deposition of amyloid microfibril material in the lung parenchyma. The condition generally presents as an indolent subacute-to-chronic pulmonary disease and requires tissue biopsy to establish the diagnosis. Nodular pulmonary amyloidosis, a subtype of pulmonary amyloidosis, is characterised by special radiographic and pathological features. While the disease can be associated with inflammatory conditions; its association with mucosal-associated lymphoid tissue (MALT lymphoma) is unusual and carries management challenges. Herein, we illustrate a case study of nodular pulmonary amyloidosis associated with underlying MALT lymphoma in a patient with known systemic lupus erythematosus. The aim of this article is to share the management experience of this complex condition with the medical community and to conduct an up-to-date literature review on nodular pulmonary amyloidosis.

Hepatic Amyloidosis: Something That Can camouflage and Deceive our Perception!

Amyloidosis is a multi-systemic diffusely infiltrating disease due to extracellular deposition of protein-mucopolysaccharide complexes. The type of protein deposited determines the subgroup of amyloid. Hepatic amyloidosis is a rare infiltrating disease affecting the hepatic parenchyma. A wide range of clinical presentation and atypical imaging findings delay the diagnosis of amyloidosis, while tissue biopsy demonstrating amyloid deposits is vital for a definitive diagnosis.

Effect of amino acid mutations on the conformational dynamics of amyloidogenic immunoglobulin light-chains: A combined NMR and in silico study

The conformational dynamics of a pathogenic κ4 human immunoglobulin light-chain variable domain, SMA, associated with AL amyloidosis, were investigated by ¹⁵N relaxation dispersion NMR spectroscopy. Compared to a homologous light-chain, LEN, which differs from SMA at eight positions but is non-amyloidogenic in vivo, we find that multiple residues in SMA clustered around the N-terminus and CDR loops experience considerable conformational exchange broadening caused by millisecond timescale protein motions, consistent with a destabilized dimer interface. To evaluate the contribution of each amino acid substitution to shaping the dynamic conformational landscape of SMA, NMR studies were performed for each SMA-like point mutant of LEN followed by in silico analysis for a subset of these proteins. These studies show that a combination of only three mutations located within or directly adjacent to CDR3 loop at the dimer interface, which remarkably include both destabilizing (Q89H and Y96Q) and stabilizing (T94H) mutations, largely accounts for the differences in conformational flexibility between LEN and SMA. Collectively, our studies indicate that a correct combination of stabilizing and destabilizing mutations is key for immunoglobulin light-chains populating unfolded intermediates that result in amyloid formation, and underscore the complex nature of correlations between light-chain conformational flexibility, thermodynamic stability and amyloidogenicity.

High-Dose Melphalan and Stem Cell Transplantation in Patients on Dialysis Due to Immunoglobulin Light-Chain Amyloidosis and Monoclonal Immunoglobulin Deposition Disease

The kidney is the most common organ affected by immunoglobulin light-chain (AL) amyloidosis and monoclonal immunoglobulin deposition disease (MIDD), often leading to end-stage renal disease (ESRD). High-dose melphalan and stem cell transplantation (HDM/SCT) is effective for selected patients with AL amyloidosis, with high rates of complete hematologic response and potential for improved organ dysfunction. Data on tolerability and response to HDM/SCT in patients with ESRD due to AL amyloidosis and MIDD are limited. We analyzed data on toxicity, efficacy, and hematologic and renal response of HDM/SCT in 32 patients with AL amyloidosis and 4 patients with MIDD who were dialysis-dependent for ESRD treated at Boston Medical Center between 1994 and 2016. The most common grade 3/4 nonhematologic toxicities were infections (75%), metabolic abnormalities (56%), mucositis (42%), constitutional symptoms (39%), pulmonary complications (39%), and diarrhea (28%). Treatment related mortality (defined as death within 100 days of SCT) occurred in 8% (3 of 36). A complete hematologic response was achieved in 70% of evaluable patients (19 of 27) at 1 year after HDM/SCT. In the entire cohort, median overall survival (OS) after HDM/SCT was 5.8 years; median OS was 1 year for those who did not achieve a complete hematologic response and 8 years for those who did achieve a complete hematologic response. Twelve patients (33%) underwent kidney transplantation after successful treatment with HDM/SCT at a median of 2.4 years after SCT. HDM/SCT is safe and effective in inducing hematologic complete responses and prolonging survival in patients with ESRD from AL amyloidosis and MIDD. Achievement of a durable hematologic response can make these patients possible candidates for renal transplantation.

A longitudinal evaluation of health-related quality of life in patients with AL amyloidosis: associations with health outcomes over time

Light chain (AL) amyloidosis is a rare disease associated with significant, irreversible organ dysfunction and high case fatality. An observational study was conducted to assess health‐related quality of life (HRQoL) in patients treated for AL amyloidosis between 1994 and 2014 with both high dose melphalan and stem cell transplantation (HDM/SCT) or non‐SCT chemotherapy regimens. The SF‐36v1^® Health Survey (SF‐36) was administered to assess HRQoL during clinic visits. Analysis of variance was used to compare pre‐ and post‐treatment HRQoL within each treatment group to an age‐ and gender‐adjusted general population (GP) normative sample. Cox proportional hazard models were fit to examine associations between pre‐treatment levels of HRQoL and mortality within 1 and 5 years after initiating specific treatment regimens (HDM/SCT: n = 402; non‐SCT chemotherapy regimens: n = 172). Among patients who received HDM/SCT, there were significant improvements following treatment in vitality, social functioning, role‐emotional and mental health. Worse pre‐treatment SF‐36 physical component scores were associated with a greater risk of mortality in both treatment groups and follow‐up periods (P ≤ 0·005 for both). [Correction added on 20 October 2017, after first online publication: This P value has been corrected]. Using HRQoL assessments in every physician visit or treatment may provide valuable insights for treating rare conditions like AL amyloidosis.

Transthyretin Cardiac Amyloidosis

PURPOSE OF REVIEW

Transthyretin (TTR)-related cardiac amyloidosis is a progressive infiltrative cardiomyopathy that mimics hypertensive, hypertrophic heart disease and may go undiagnosed. Transthyretin-derived amyloidosis accounts for 18% of all cases of cardiac amyloidosis. Thus, the study's purpose is to provide a comprehensive review of transthyretin cardiac amyloidosis.

RECENT FINDINGS

Wild-type transthyretin (ATTRwt) protein causes cardiac amyloidosis sporadically, with 25 to 36% of the population older than 80 years of age are at risk to develop a slowly progressive, infiltrative amyloid cardiomyopathy secondary to ATTRwt. In contrast, hereditary amyloidosis (ATTRm) is an autosomal dominant inherited disease associated with more than 100 point mutations in the transthyretin gene and has a tendency to affect the heart and nervous system. Up to 4% of African-Americans carry the Val122Ile mutation in the transthyretin gene, the most prevalent cause of hereditary cardiac amyloidosis in the USA. Identifying transthyretin cardiac amyloidosis requires increased awareness of the prevalence, signs and symptoms, and diagnostic tools available for discrimination of this progressive form of cardiomyopathy associated with left ventricular hypertrophy. While there are no FDA-approved medical treatments, investigation is underway on agents to reduce circulating mutated transthyretin.

Inotropic myocardial reserve deficiency is the predominant feature of exercise haemodynamics in cardiac amyloidosis

AIMS

This study aimed to characterize invasive haemodynamics during exercise in subjects with cardiac amyloidosis (CA).

METHODS AND RESULTS

The study population numbered 44 subjects. Group A (CA-positive, n = 24) comprised wild-type transthyretin patients (n = 10), familial transthyretin amyloidosis mutation carriers (ATTRm) with cardiac involvement (n = 5), and light-chain amyloidosis patients with cardiac involvement (n = 9). Group B (CA-negative, n = 20) comprised four healthy ATTRm subjects without cardiac involvement documented by ¹¹ C-PIB positron emission tomography and 16 healthy controls. All subjects underwent a symptom-limited, semi-supine exercise test with expired gas analysis and simultaneous right heart catheterization. CA patients had lower peak oxygen consumption [15 ± 6 mL/min/kg bodyweight (bwt) vs. 33 ± 7 mL/min/kg bwt; P < 0.0001] than controls. Myocardial reserve during exercise was significantly reduced in CA patients as reflected in a small increase in stroke volume index (SVI) and cardiac index (CI) compared with controls [ΔSVI: 4 mL/m² (range: -1 to 8) vs. 14 mL/m² (range: 5-25); P < 0.0001; ΔCI: 2 ± 2 L/min vs. 7 ± 2 L/min; P < 0.0001]. During exercise, CA patients had significantly higher left and right ventricular filling pressures than controls. Furthermore, CA patients had severely impaired pulmonary arterial compliance (PAC) compared with controls [2.9 mL/mmHg (range: 2.1-4.5) vs. 7.5 mL/mmHg (range: 5.7-10.4); P < 0.0001].

CONCLUSIONS

Cardiac amyloid deposits are associated with severely reduced inotropic myocardial reserve and increased left and right ventricular filling pressures during exercise. Furthermore, CA subjects have severely reduced PAC, which may contribute to right heart failure and reduced exercise capacity.

Contribution of human smooth muscle cells to amyloid angiopathy in AL (light-chain) amyloidosis

OBJECTIVE

Amyloid light-chain (AL) amyloidosis is a disease process that often compromises the peripheral vascular system and leads to systemic end-organ dysfunction. Although amyloid formation in vessel walls is a multifaceted process, the assembly of the native light chains (LCs) into amyloid fibrils is central to its pathogenesis. Recent evidence suggests that endocytosis and endolysosomal processing of immunoglobin LCs by host cells is essential to the formation of amyloid fibrils that are deposited in at least some tissues. The aim of this study was to elucidate the role of vascular smooth muscle in amyloid angiopathy.

METHODS

Human coronary artery smooth muscle cells (SMCs) were grown on coverslips, four chamber glass slides, and growth factor-reduced Matrigel matrix in the presence of 10 µg/ml of ALs (λ and κ isotypes), nonamyloidogenic LCs, and culture medium (negative control) for 48 and 72 hours. Thereafter, a detailed light microscopic, immunohistochemical, and ultrastructural evaluation was conducted to verify amyloid deposition and characterize the role of SMCs in the formation of amyloid deposits in the various experimental conditions.

RESULTS

Amyloid deposits were detected extracellulary as early as 48 hours after exposure of vascular smooth muscle cells (VSMCs) to AL-LCs (amyloidogenic light chains) as confirmed by affinity to Congo red dye, thioflavin T fluorescence, and transmission electron microscopy. No amyloid was present in the cultures of SMCs treated with medium alone or nonamyloidogenic LCs. SMCs associated with amyloid deposits exhibited CD68, lysosome-associated membrane protein 1-1, and intracellular lambda light chain expression and only focal smooth muscle actin and muscle-specific actin positivity. Electron microscopy revealed these cells to have an expanded mature lysosomal compartment closely associated with deposits of newly formed amyloid fibrils.

CONCLUSIONS

The interaction of amyloidogenic LCs with VSMCs is necessary for the formation of amyloid fibrils that are deposited in peripheral vessels. VSMCs participate in the formation of amyloid by the intracellular processing of AL-LCs, which is possible due to their transformation from a smooth muscle to a macrophage phenotype. The formation of amyloid fibrils occurs in the mature lysosomal compartment of transformed cells. The amyloid that is formed is then extruded into the extracellular matrix.

Genotype and Phenotype of Transthyretin Cardiac Amyloidosis: THAOS (Transthyretin Amyloid Outcome Survey)

BACKGROUND

Transthyretin amyloidosis (ATTR) is a heterogeneous disorder with multiorgan involvement and a genetic or nongenetic basis.

OBJECTIVES

The goal of this study was to describe ATTR in the United States by using data from the THAOS (Transthyretin Amyloidosis Outcomes Survey) registry.

METHODS

Demographic, clinical, and genetic features of patients enrolled in the THAOS registry in the United States (n = 390) were compared with data from patients from other regions of the world (ROW) (n = 2,140). The focus was on the phenotypic expression and survival in the majority of U.S. subjects with valine-to-isoleucine substitution at position 122 (Val122Ile) (n = 91) and wild-type ATTR (n = 189).

RESULTS

U.S. subjects are older (70 vs. 46 years), more often male (85.4% vs. 50.6%), and more often of African descent (25.4% vs. 0.5%) than the ROW. A significantly higher percentage of U.S. patients with ATTR amyloid seen at cardiology sites had wild-type disease than the ROW (50.5% vs. 26.2%). In the United States, 34 different mutations (n = 201) have been reported, with the most common being Val122Ile (n = 91; 45.3%) and Thr60Ala (n = 41; 20.4%). Overall, 91 (85%) of 107 patients with Val122Ile were from the United States, where Val122Ile subjects were younger and more often female and black than patients with wild-type disease, and had similar cardiac phenotype but a greater burden of neurologic symptoms (pain, numbness, tingling, and walking disability) and worse quality of life. Advancing age and lower mean arterial pressure, but not the presence of a transthyretin mutation, were independently associated with higher mortality from a multivariate analysis of survival.

CONCLUSIONS

In the THAOS registry, ATTR in the United States is overwhelmingly a disorder of older adult male subjects with a cardiac-predominant phenotype. Val122Ile is the most common transthyretin mutation, and neurologic phenotypic expression differs between wild-type disease and Val122Ile, but survival from enrollment in THAOS does not. (Transthyretin-Associated Amyloidoses Outcome Survey [THAOS]; NCT00628745).

Proteostasis in cardiac health and disease

The incidence and prevalence of cardiac diseases, which are the main cause of death worldwide, are likely to increase because of population ageing. Prevailing theories about the mechanisms of ageing feature the gradual derailment of cellular protein homeostasis (proteostasis) and loss of protein quality control as central factors. In the heart, loss of protein patency, owing to flaws in genetically-determined design or because of environmentally-induced 'wear and tear', can overwhelm protein quality control, thereby triggering derailment of proteostasis and contributing to cardiac ageing. Failure of protein quality control involves impairment of chaperones, ubiquitin-proteosomal systems, autophagy, and loss of sarcomeric and cytoskeletal proteins, all of which relate to induction of cardiomyocyte senescence. Targeting protein quality control to maintain cardiac proteostasis offers a novel therapeutic strategy to promote cardiac health and combat cardiac disease. Currently marketed drugs are available to explore this concept in the clinical setting.

Significant association between renal function and area of amyloid deposition in kidney biopsy specimens in both AA amyloidosis associated with rheumatoid arthritis and AL amyloidosis

The kidney is a major target organ for systemic amyloidosis, which results in proteinuria and an elevated serum creatinine level. The clinical manifestations and precursor proteins of amyloid A (AA) and light-chain (AL) amyloidosis are different, and the renal damage due to amyloid deposition also seems to differ. The purpose of this study was to clarify haw the difference in clinical features between AA and AL amyloidosis are explained by the difference in the amount and distribution of amyloid deposition in the renal tissues. A total of 119 patients participated: 58 patients with an established diagnosis of AA amyloidosis (AA group) and 61 with AL amyloidosis (AL group). We retrospectively investigated the correlation between clinical data, pathological manifestations, and the area occupied by amyloid in renal biopsy specimens. In most of the renal specimens the percentage area occupied by amyloid was less than 10%. For statistical analyses, the percentage area of amyloid deposition was transformed to a common logarithmic value (Log₁₀%amyloid). The results of sex-, age-, and Log₁₀%amyloid-adjusted analyses showed that systolic blood pressure (SBP) was higher in the AA group. In terms of renal function parameters, serum creatinine, creatinine clearance (Ccr) and estimated glomerular filtration rate (eGFR) indicated significant renal impairment in the AA group, whereas urinary protein indicated significant renal impairment in the AL group. Pathological examinations revealed amyloid was predominantly deposited at glomerular basement membrane (GBM) and easily transferred to the mesangial area in the AA group, and it was predominantly deposited at in the AL group. The degree of amyloid deposition in the glomerular capillary was significantly more severe in AL group. The frequency of amyloid deposits in extraglomerular mesangium was not significantly different between the two groups, but in AA group, the degree amyloid deposition was significantly more severe, and the deposition pattern in the glomerulus was nodular. Nodular deposition in extraglomerular mesangium leads to renal impairment in AA group. There are significant differences between AA and AL amyloidosis with regard to the renal function, especially in terms of Ccr, eGFR and urinary protein, even after Log10%amyloid was adjusted; showing that these inter-group differences in renal function would not be depend on the amount of renal amyloid deposits. These differences could be explained by the difference in distribution and morphological pattern of amyloid deposition in the renal tissue.

Preclinical data support leveraging CS1 chimeric antigen receptor T-cell therapy for systemic light chain amyloidosis

BACKGROUND AIMS

Light chain amyloidosis (AL) is a protein deposition disorder that is a result of a plasma cell dyscrasia, similar to multiple myeloma (MM). Immunotherapy is an attractive approach because of the low burden of disease, but the optimal target for AL is unclear. CS1 and B-cell maturation antigen (BCMA) are two potential targets because they are expressed on normal plasma cells and MM cells.

METHODS

We performed a prospective study evaluating bone marrow specimens of 20 patients with plasma cell diseases, 10 with AL and 10 with MM. We evaluated the clonal population of plasma cells for BCMA and CS1 expression. We designed a second-generation CS1 chimeric antigen receptor (CAR) construct, comprising a CS1 antigen-specific scFv, shortened hinge region and CD28 costimulatory domain. Purified central memory T cells were activated and transduced with a lentiviral vector encoding the CS1 CAR. Cytotoxicity was evaluated using ⁵¹Cr release assays. Five days after tumor inoculation, NSG mice were injected intravenously with CS1 CAR T cells.

RESULTS

Whereas CS1 is present on the plasma cells of AL patients, we found BCMA expression in AL to be markedly low. CS1 CAR T cells were cytotoxic against CS1 positive tumor cells and induced durable tumor regressions in mice.

DISCUSSION

Our work represents a novel application of CS1-directed CAR T cells while revealing that BCMA would not be a suitable target. We expect AL to be particularly susceptible to CAR T-cell therapy because of the low tumor burden in the bone marrow.

Cardiovascular magnetic resonance myocardial T1 mapping to detect and quantify cardiac involvement in familial amyloid polyneuropathy

OBJECTIVES

This study sought to explore the potential role of non-contrast T1 mapping for the detection and quantification of cardiac involvement in familial amyloid polyneuropathy (FAP).

METHODS

Japanese patients with FAP [n = 41, age 53.2 ± 13.9 years, genotype Val30Met (n = 25), non-Val30Met (n = 16)] underwent cardiac magnetic resonance imaging that included T1 mapping (saturation-recovery method) and late gadolinium-enhanced (LGE) imaging on a 3.0-T MR scanner. Their native T1 was measured on mid-ventricular short-axis images and compared with 30 controls.

RESULTS

Of the 41 FAP patients 29 were LGE positive. The native T1 was significantly higher in FAP patients than in the controls (1,634.1 ± 126.3 ms vs. 1,432.4 ± 69.0 ms, p < 0.01), significantly higher in LGE-positive- than LGE-negative FAP patients (1,687.1 ± 104.4 ms vs. 1,505.4 ± 68.5 ms, p < 0.01), and significantly higher in LGE-negative FAP patients than the controls (p < 0.01). A native T1 cutoff value of 1,610 ms yielded 85.4% accuracy for identifying LGE-positive FAP. The native T1 significantly correlated with the interventricular septum wall thickness, the left ventricular mass, the LGE volume, the plasma B-type natriuretic peptide level, and the E/e' ratio (all p < 0.01).

CONCLUSION

T1 mapping is of high diagnostic accuracy for the detection of LGE-positive FAP. The native myocardial T1 may be correlated with the severity of cardiac amyloid deposition.

KEY POINTS

• The native T1 was higher in FAP patients than the controls. • The native T1 was higher in LGE-positive- than LGE-negative FAP patients. • The native T1 was higher in LGE-negative FAP patients than the controls. • The native T1 correlated with clinical markers of systolic and diastolic dysfunction. • Myocardial T1 mapping is of high diagnostic accuracy for detecting LGE-positive FAP.