Molecular mechanisms of amyloidosis

Speckle-Tracking Echocardiography in Cardio-Oncology and Beyond

Speckle-tracking echocardiography has enabled clinicians to detect changes in myocardial function with more sensitivity than that afforded by traditional diastolic and systolic functional measurements, including left ventricular ejection fraction. Speckle-tracking echocardiography enables evaluation of myocardial strain in terms of strain (percent change in length of a myocardial segment relative to its length at baseline) and strain rate (strain per unit of time). Both measurements have potential for use in diagnosing and monitoring the cardiovascular side effects of cancer therapy. Regional and global strain measurements can independently predict outcomes not only in patients who experience cardiovascular complications of cancer and cancer therapy, but also in patients with a variety of other clinical conditions. This review and case series examine the clinical applications and overall usefulness of speckle-tracking echocardiography in cardio-oncology and, more broadly, in clinical cardiology.

Laryngotracheobronchial Amyloidosis: Patterns of Presentation and Management

OBJECTIVE

To evaluate the pattern of presentation and management of laryngotracheobronchial amyloidosis at a tertiary care academic center over a 27 year period.

METHODS

In a retrospective review, the electronic medical record at a tertiary care academic center was queried for encounters with 3 laryngologists between 1996 and 2019 which included the ICD-9 or ICD-10 diagnosis of amyloidosis. Demographics, clinical presentation, referral diagnoses, medical history, family history, laboratory values, radiology studies, and treatment modalities of subjects were collated. Results were analyzed using standard univariate descriptive statistics.

RESULTS

Seventeen subjects were identified with an average age at diagnosis of 58 years (range 26-76 years). The most common amyloid type on biopsy was immunoglobulin light chain (AL) subtype. The most common location of laryngeal amyloid at diagnosis was the glottis and disease was more likely to be bilateral at the time of diagnosis in this location. Supraglottic disease more often had a unilateral presentation and had a tendency to spread to additional laryngeal subsites. Nearly 25% of subjects had associated systemic disease, including multiple myeloma, auto-immune disease, and familial ATTR mutation.

CONCLUSIONS

The overall rate of associated systemic disease was low in our study cohort; however, it is higher than typically referenced in extant literature. Our cohort demonstrates that while laryngeal amyloidosis is a chronic condition, the behavior is generally indolent with a low treatment burden.

Systemic Amyloidosis: a Contemporary Overview

Amyloidosis constitutes a large spectrum of diseases characterized by an extracellular deposition of a fibrillar aggregate, generating insoluble and toxic amasses that may be deposited in tissues in bundles with an abnormal cross-β-sheet conformation, known as amyloid. Amyloid may lead to a cell damage and an impairment of organ function. Several different proteins are recognized as able to produce amyloid fibrils with a different tissue tropism related to the molecular structure. The deposition of amyloid may occur as a consequence of the presence of an abnormal protein, caused by high plasma levels of a normal protein, or as a result of the aging process along with some environmental factors. Although amyloidosis is rare, amyloid deposits play a role in several conditions as degenerative diseases. Thus, the development of antiamyloid curative treatments may be a rational approach to treat neurodegenerative conditions like Alzheimer's disease in the future. Nowadays, novel treatment options are currently refined through controlled trials, as new drug targets and different therapeutic approaches have been identified and validated through modern advances in basic research. Fibril formation stabilizers, proteasome inhibitors, and immunotherapy revealed promising results in improving the outcomes of patients with systemic amyloidosis, and these novel algorithms will be effectively combined with current treatments based on chemotherapeutic regimens. The aim of this review is to provide an update on diagnosis and treatment for systemic amyloidosis.

Phasic left atrial strain analysis to discriminate cardiac amyloidosis in patients with unclear thick heart pathology

AIMS

Traditional echocardiographic parameters for the assessment of suspected cardiac amyloidosis (CA) are of limited diagnostic accuracy. We sought to explore differences and the discriminative value of phasic left atrial strain (LAS) reductions and of regional longitudinal left ventricular (LV) strain alterations (relative apical sparing; RELAPS) in CA and other causes of LV wall thickening (LVH).

METHODS AND RESULTS

We included 54 patients with unclear LVH (mean septal diastolic wall thickness 17.8 ± 3.5 mm); CA was bioptically confirmed in 35 patients (8 mATTR, 6 wtATTR, 20 AL, and 1 AA amyloidosis) and LVH in 19 subjects. We analysed RELAPS as well as LA reservoir (LASr), conduit (LAScd), and contraction strain (LASct) using 2D speckle tracking echocardiography (EchoPAC software, GE). RELAPS was higher (1.37 ± 0.94 vs. 0.86 ± 0.29, P < 0.007), whereas atrial mechanics were significantly reduced in CA (LASr, LAScd, and LASct: 9.7 ± 5.2%, -6.5 ± 3.5%, and -5.0 ± 4.1% in CA; and 22.7 ± 7.8%, -13.9 ± 5.2%, and -13.0 ± 5.5% in LVH, respectively; P < 0.001 each). With an area under the curve (AUC) of 0.91 [95% confidence interval (CI) 0.82-0.99], LASr showed a higher diagnostic accuracy in discriminating CA than RELAPS (AUC 0.74, 95% CI 0.59-0.88). LASr and LAScd remained significantly associated with CA in a multivariate regression model.

CONCLUSION

Phasic LAS was significantly reduced in patients with CA and showed a higher diagnostic accuracy in discriminating CA than RELAPS. The additional assessment of phasic LAS may be useful to rule in the possible diagnosis of CA in patients with unclear LVH.

Imaging Techniques as an Aid in the Early Detection of Cardiac Amyloidosis

The idea that performing a proper succession of imaging tests and techniques allows an accurate and early diagnosis of cardiac amyloidosis, avoiding the need to perform the myocardial biopsy, is becoming increasingly popular. Furthermore, being imaging techniques non-invasive, it is possible to perform the follow-up of the pathology through repeated image acquisitions. In the present review, the various innovative imaging methodologies are presented, and it is discussed how they have been applied for early diagnosis of cardiac amyloidosis (CA), also to distinguish the two most frequent subtypes in CA: immunoglobulin light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR); this allows to perform the therapy in a targeted and rapid manner.

Emphysematous Lung Lesions Caused by Perivascular and Alveolar-Septal Deposition of Amyloid Light-Chain Amyloidosis

Pulmonary amyloidosis, whether isolated or seen as part of systemic amyloidosis, has a variety of radiographic manifestations. Known parenchymal lung findings include reticulonodular opacities, diffuse interstitial infiltrates, or cystic lesions. Here, we present a case of systemic amyloid light-chain (AL) amyloidosis presenting with severe exertional dyspnea and emphysematous lung lesions on chest CT, a finding described only once before. Although factors that influence the pattern of pulmonary amyloid deposition remain unclear, CT image findings typically reflect the histopathologic patterns of deposition. In this case, we hypothesize that the emphysematous changes in the lower lung zones are likely a manifestation of severe alveolar-septal involvement. This case suggests that radiographic findings of pulmonary amyloidosis are not limited to the more common findings of reticular opacities or interstitial infiltrates. Emphysematous changes are possible, and clinicians should maintain a broad differential when seen in the setting of dyspnea.

Incidence rate of hospitalization and mortality in the first year following initial diagnosis of cardiac amyloidosis in the US claims databases

OBJECTIVE

This study aimed to determine rates of hospitalization and in-hospital mortality in the first year following amyloidosis diagnosis with cardiac involvement using observational databases.

METHODS

Three administrative claims databases, IBM MarketScan^® Commercial Claims and Encounters (CCAE), IBM MarketScan^® Multi-State Medicare Database (MDCR), and Optum's de-identified Clinformatics^® Data Mart Database (Optum) were analyzed. Adults ≥18 years old, with a diagnosis of amyloidosis and evidence of cardiac involvement (i.e. heart failure, heart block, or cardiomyopathy) but no hepatic/renal failure prior to amyloidosis diagnosis were included for analysis. The primary analyses identified patients between 01-01-2010 and 31-12-2017 period. We calculated the rates of hospitalization and in-hospital mortality within 1 year after the initial diagnosis of amyloidosis. A sensitivity analysis was conducted for patients identified in Optum database during 2004-2011 period, which provided additional mortality information.

RESULTS

A total of 419, 654, and 922 patients from CCAE, MDCR, and Optum were identified during 2010-2017 period, with mean age of 55.6, 77.8, and 74.2 years, respectively. Within 1 year following initial amyloidosis diagnosis, incidence rates (95% confidence interval [CI]) of hospitalization were 78.4 (66.3, 90.4), 78.6 (69.2, 87.9), and 61.2 (54.4, 68.0) per 100 person-years, rates of in-hospital mortality were 16.5 (11.8, 21.3), 8.4 (5.7, 11.0), and 17.7 (14.5, 21.0) per 100 person-years, in CCAE, MDCR, and Optum, respectively. The mortality rate from the sensitivity analysis among patients identified in Optum 2004-2011 period was higher compared with Optum 2010-2017 period.

CONCLUSIONS

The results from this study indicate that amyloidosis with cardiac involvement is a condition with high rates of hospitalization and mortality in the first year after initial diagnosis. Future studies are needed to further evaluate the outcomes within the subtypes of amyloidosis and understand the risk factors associated with poor prognoses.

18F-sodium fluoride PET/MRI myocardial imaging in patients with suspected cardiac amyloidosis

BACKGROUND

We evaluated the diagnostic performance of 18F-NaF PET/MRI in patients with suspected cardiac amyloidosis (CA).

METHODS

Twenty-seven consecutive patients underwent myocardial PET 1 hour after injection of 4 MBq/kg 18F-NaF with simultaneous MRI including cine-MRI, T1 and T2 mapping, first-pass and late gadolinium enhancement (LGE). 18F-NaF uptake was measured visually and semi-quantitatively by calculating myocardium-to-blood pool (M/B) ratios. CA was confirmed histologically.

RESULTS

Transthyretin (TTR)-CA was diagnosed in 16 patients, light-chain (AL)-CA in 7, and no-CA in 4. Visual interpretation of 18F-NaF images revealed a relative increase in myocardial uptake in only 3 patients, all with TTR CA, and a relative decrease in 13, including 7 AL CA, 3 no-CA, and 3 TTR CA. M/B ratios were significantly higher in TTR CA (1.00 ± 0.12) than in AL CA (0.81 ± 0.06, P = 0.001) or in no-CA (0.73 ± 0.16, P = 0.006). The optimal M/B cut-off to distinguish TTR CA from AL CA was ≥ 0.90 (Fischer, P = 0.0005). By comparison, classification of patients using 99mTc-HMDP heart-to-mediastinum ratios with the previously published cut-off ≥ 1.21 reached higher significance (P < 0.0001). Among MRI parameters, myocardial T1, LGE score, and extracellular volume were higher in CA than in no-CA patients, 1409 ± 76 vs 1278 ± 35 ms (P = 0.004), 10.35 ± 5.30 vs 3.50 ± 3.42 (P = 0.03), and 46 ± 10 vs 33 ± 8 % (P = 0.01), respectively.

CONCLUSION

18F-NaF PET/MRI shows good diagnostic performance when semi-quantification is used. However, contrast is low and visual interpretation may be challenging in routine. PET/MRI could constitute a one-stop-shop evaluation of amyloid load and cardiac function in patients needing rapid work-up.

Progress in research: Daratumumab improves treatment outcomes of patients with AL amyloidosis

Outcomes for patients with systemic light-chain (AL) amyloidosis have improved over the last two decades with timely diagnosis, use of novel chemotherapeutic agents, risk stratification and better patient selection criteria before hematopoietic autologous stem cell transplant (ASCT). However, majority of patients have advanced stage disease at initial presentation and at relapse rendering them ineligible for intensive cytotoxic chemotherapy or ASCT. Daratumumab (Dara) with or without standard chemotherapy appears to be an excellent treatment option for newly diagnosed and relapsed refractory AL amyloidosis. This is largely due to its tolerable safety and remarkable efficacy as seen in multiple retrospective, small phase II studies as well as a phase III randomized controlled trial. Here we review published clinical trials and retrospective data of Dara in AL amyloidosis that explore its role as a valuable addition to the treatment armamentarium for this challenging disease.

Nonenhanced Chemical Exchange Saturation Transfer Cardiac Magnetic Resonance Imaging in Patients With Amyloid Light-Chain Amyloidosis

BACKGROUND

Chemical exchange saturation transfer (CEST) is an emerging metabolic MRI technique to map creatine distribution in the myocardium.

PURPOSE

To investigate the feasibility of using a contrast-free CEST technique to evaluate cardiac involvement in amyloid light-chain (AL) amyloidosis.

STUDY TYPE

Prospective.

POPULATION

Forty patients with biopsy-proven AL amyloidosis (age 57.6 ± 9.1 years, 31 males) and 20 healthy controls (age 42.8 ± 13.8 years, 13 males).

FIELD STRENGTH/SEQUENCE

A 3.0 T, CEST imaging using a single-shot FLASH sequence, T1 mapping with a modified Look-Locker inversion recovery sequence and late gadolinium enhancement (LGE) imaging with a phase-sensitive inversion recovery gradient echo sequence.

ASSESSMENT

The average CEST was calculated in the basal short-axis slice of the entire left ventricle and septum. LGE was assessed subjectively (none/patchy/global) and extracellular volume (ECV), CEST and T1 maps generated.

STATISTICAL TESTS

Comparison between patient groups and healthy controls was performed by one-way analysis of variance with post hoc Bonferroni correction. Correlation was assessed using the Pearson's r correlation or Spearman ρ correlation. Statistical significance was defined as P < 0.05.

RESULTS

Global (0.09 ± 0.03 vs. 0.11 ± 0.02) and septal (0.09 ± 0.03 vs. 0.11 ± 0.03) basal short-axis CEST was significantly decreased in patients with AL amyloidosis compared to the controls. Global CEST correlated significantly with Mayo stage (ρ = -0.508), NYHA Class (ρ = -0.430), LVEF (r = 0.511), mass index (r = -0.373), LGE (ρ = -0.537), ECV (r = -0.544), and T2 (r = -0.396). Septal CEST correlated significantly with LVEF (r = 0.395), LGE (ρ = -0.330), and ECV (r = -0.391).

DATA CONCLUSIONS

This study highlights the potential of CEST MRI to identify cardiac involvement and evaluate disease burden and to give insight into cellular changes intermediary between function and structure in AL amyloidosis patients.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

The amyloid proteome: a systematic review and proposal of a protein classification system

Amyloidosis is a disease caused by pathological fibril aggregation and deposition of proteins in different tissues and organs. Thirty-six fibril-forming proteins have been identified. So far, proteomic evaluation of amyloid focused on the detection and characterization of fibril proteins mainly for diagnostic purposes or to find novel fibril-forming proteins. However, amyloid deposits are a complex mixture of constituents that show organ-, tissue-, and amyloid-type specific patterns, that is the amyloid proteome. We carried out a comprehensive literature review on publications investigating amyloid via liquid chromatography coupled to tandem mass spectrometry, including but not limited to sample preparation by laser microdissection. Our review confirms the complexity and dynamics of the amyloid proteome, which can be divided into four functional categories: amyloid proteome-category 1 (APC1) includes exclusively fibrillary proteins found in the patient; APC2 includes potential fibril-forming proteins found in other types of amyloid; and APC3 and APC4 summarizes non-fibril proteins-some being amyloid signature proteins. Our categorization may help to systemically explore the nature and role of the amyloid proteome in the manifestation, progression, and clearance of disease. Further exploration of the amyloid proteome may form the basis for the development of novel diagnostic tools, thereby enabling the development of novel therapeutic targets.

Cardiac Amyloidosis: Diagnostic Tools for a Challenging Disease

Amyloidosis is a group of diseases in which amyloid fibrils build up in tissues, leading to organ dysfunction. Cardiac involvement is observed in immunoglobulin light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR) and, when it occurs, the prognosis worsens. Cardiac tissue infiltration can lead to restrictive cardiomyopathy with clinical signs of diastolic heart failure, without reduction of ejection fraction (HFpEF). The aim of multiple and less invasive diagnostic tests is to discern peculiar characteristics and reach the diagnosis without performing an invasive endomyocardial biopsy. These diagnostic tools allow early diagnosis, and they are crucial to best benefit from target therapy. In this review article, we describe the mechanism behind amyloid fibril formation, infiltration of tissues, and consequent clinical signs, focusing on the diagnostic tools and the red flags to obtain a diagnosis.

Thymic amyloidoma mimicking sclerosing thymoma in a triple vessel disease patient: An incidental finding

A 65 year old man who underwent coronary artery bypass graft (CABG) for triple vessel disease was found to have enlarged thymus. Biopsy of the thymic mass revealed localised amyloid deposits demonstrating strong apple green birefringence on polarised microscopy. Localized thymic amyloidosis is an extremely rare finding with present case as the seventh in the world and the first in India. Review of literature of thymic amyloidoma and its close differential sclerosing thymoma is hereby described.

Search for AL amyloidosis risk factors using Mendelian randomization

In amyloid light chain (AL) amyloidosis, amyloid fibrils derived from immunoglobulin light chain are deposited in many organs, interfering with their function. The etiology of AL amyloidosis is poorly understood. Summary data from genome-wide association studies (GWASs) of multiple phenotypes can be exploited by Mendelian randomization (MR) methodology to search for factors influencing AL amyloidosis risk. We performed a 2-sample MR analyzing 72 phenotypes, proxied by 3461 genetic variants, and summary genetic data from a GWAS of 1129 AL amyloidosis cases and 7589 controls. Associations with a Bonferroni-defined significance level were observed for genetically predicted increased monocyte counts (P = 3.8 × 10-4) and the tumor necrosis factor receptor superfamily member 17 (TNFRSF17) gene (P = 3.4 × 10-5). Two other associations with the TNFRSF (members 6 and 19L) reached a nominal significance level. The association between genetically predicted decreased fibrinogen levels may be related to roles of fibrinogen other than blood clotting. be related to its nonhemostatic role. It is plausible that a causal relationship with monocyte concentration could be explained by selection of a light chain-producing clone during progression of monoclonal gammopathy of unknown significance toward AL amyloidosis. Because TNFRSF proteins have key functions in lymphocyte biology, it is entirely plausible that they offer a potential link to AL amyloidosis pathophysiology. Our study provides insight into AL amyloidosis etiology, suggesting high circulating levels of monocytes and TNFRSF proteins as risk factors.

Species-barrier on the cross-species oral transmission of bovine AA amyloidosis in mice

In AA amyloidosis, cross-species oral transmission has been demonstrated in several animal models. While it is known that the transmission efficiency of AA amyloidosis between different species is lower than that among the same species, the mechanism of this species-barrier is unclear. In this study, we found at first that mice orally given a large amount of bovine AA simultaneously with inflammatory stimulation did not develop AA amyloidosis. Therefore, we hypothesized that the low efficiency of the cross-species oral transmission of AA amyloidosis might be due to the low absorption rate in Peyer's patches. To evaluate the hypothesis, we next investigated whether bovine AA was taken up by Peyer's patches and translocated to other organs in vivo and ex vivo models. The direct absorption of bovine AA by Peyer's patches was not observed. Besides, translocation of bovine AA to the mesenteric lymph nodes, spleen, liver, or kidney was not observed except the mesenteric lymph node of a single mouse. Thus, absorption of bovine AA by Peyer's patches occurred much less efficiently in mouse models of cross-species oral transmission of AA amyloidosis. The present study suggests that the less efficient amyloid uptake by Peyer's patches may be involved in the species-barrier of oral transmission of AA amyloidosis.

Impact of time to diagnosis on Mayo stages, treatment outcome, and survival in patients with AL amyloidosis and cardiac involvement

OBJECTIVE

To study the impact of time to diagnosis on cardiac Mayo stages, treatment outcome, and overall survival.

METHODS

We retrospectively analyzed 77 consecutive patients diagnosed between 2015 and 2020 with AL amyloidosis and cardiac involvement. Medical history was recorded in standardized form with the help of a questionnaire.

RESULTS

Time from onset of symptoms of cardiac failure to diagnosis was correlated with the severity of cardiac involvement in modified Mayo 2004 and revised Mayo 2012 staging systems (r_s  = 0.30, 95% CI: 0.07-0.50, P = .007 and r_s  = 0.25, 95% CI: 0.01-0.45, P = .03). Patients with advanced Mayo 2004 stages received reduced-intensity regimens and had a lower probability to achieve adequate hematologic- and cardiac response after first-line treatment than patients with early stages (r_s  = 0.28, 95% CI: 0.04-0.48, P = .01 and r_s  = 0.72, 95% CI: 0.55-0.82, P < .0001) and poorer overall survival (P = .0004). Compared with patients diagnosed within the first year, patients diagnosed after 13-18 or ≥19 months from first symptoms had a 3- to 5 times higher risk of dying. Our data indicate that there is a 12-month window within which the diagnosis of AL amyloidosis needs to be established to avoid early deterioration and death.

CONCLUSIONS

Sensitizing physicians and raising awareness for the disease are crucial for timely diagnosis and may improve the outcome of the disease.

Pure neural leprosy or amyloid neuropathy? Systematic review and clinical case report

OBJECTIVE

To review the literature and to report a clinical case with initial suspicion of pure neural leprosy and final diagnosis of amyloid neuropathy.

METHODS

The study was conducted in two stages. In stage one, a systematic literature review was carried out, with searches performed in the PubMed, Medline, and Lilacs databases, as well as in the leprosy sectoral library of the Virtual Health Library, using the following descriptors: neuritic leprosy, pure neural leprosy, primary neural leprosy, pure neuritic leprosy, amyloid polyneuropathy, amyloid neuropathies, and amyloid polyneuropathy. The search was carried out on May 28, 2020. Clinical trials, cohort studies, cross-sectional studies, clinical cases, and case studies published in Portuguese, English or Spanish between 2010 and 2020 were included. Stage two reports a case with initial suspicion of pure neural leprosy. Laboratory tests, electroneuromyography, ultrasound, and biopsy of the sural nerve were requested.

RESULTS

Twenty-three scientific texts were included. No publications were found that contained both topics together. The challenging diagnosis of pure neural leprosy and the possibility of using auxiliary resources in diagnosis were the most emphasized themes in the studies. In the clinical case, the patient's electroneuromyography showed sensitive and motor polyneuropathy of the lower limbs, which was predominantly sensory and axonal, symmetrical, of moderate intensity, and the mixed type (axonal-demyelinating). Ultrasonography of the sural nerve revealed changes in the contour of the deep fibular nerves; biopsy of the sural nerve showed an accumulation of amorphous eosinophilic material in the nerve path, and Congo red stain showed apple-green birefringence of the deposit under polarized light. The final diagnosis was amyloid neuropathy.

CONCLUSIONS

The final clinical diagnosis was amyloid neuropathy. The diagnosis of pure neural leprosy in endemic areas in Brasil is still a challenge for the health system.

Wild-type ATTR amyloidosis of the prostate: a case review

The amyloidoses are a rare group of disorders caused by the deposition of amyloid fibrils in organ tissues. Transthyretin-mediated amyloidosis is a subcategory of amyloidosis, which can be further subdivided into hereditary transthyretin-mediated or wild-type (‘senile’) amyloidosis. Involvement of the prostate by any type of amyloidosis is rare, with only a handful of cases reported in the literature. We report here a case of a 64-year-old Caucasian man who was incidentally found to have wild-type transthyretin-mediated amyloidosis of the prostate following a radical prostatectomy for treatment of a localised, Gleason 7 (4 + 3) adenocarcinoma of the prostate. TTR subtyping was confirmed by mass spectrometry. His family history was negative for known amyloidosis, and sequencing of the entire TTR gene was negative for any mutations, so he was therefore considered to have wild-type TTR amyloidosis. He was subsequently found to have additional foci of amyloid deposition in the gastrointestinal tract. Wild-type transthyretin-mediated amyloidosis as an incidental finding in a prostate biopsy is an extremely rare finding. Treatment options for transthyretin-mediated amyloidosis are limited, and further research and treatment options are needed in this rare and difficult to manage disease.

Level of evidence: The level of evidence according to the Oxford Centre of Evidence-based Medicine levels of evidence is not applicable to this case report. Given that this is a rare entity, decisions made in managing this case were based on a level of evidence of 5.

Blockade of interleukin-6 as a possible therapeutic target for AA amyloidosis

INTRODUCTION

AA (secondary) amyloidosis is a severe complication of chronic inflammatory disorders. It is characterized by the systemic deposition of an abnormal protein called amyloid, affecting mainly renal function. IL-6 is a cytokine with a relevant role in this disease development. Interleukin-receptor antagonists, like Tocilizumab (TCZ), have become possible treatment choice for AA amyloidosis. In published reports, TCZ has shown good efficacy for AA amyloidosis, being associated with regression of renal amyloid deposits.

METHODS

Retrospective review that included patients with histological diagnosis of AA renal amyloidosis under treatment with TCZ during the years 2018-2019 in our center. We have registered clinical and demographic variables. Renal function was measured by means of CKD-EPI equation to estimate the glomerular filtration rate (FG) and protein/creatinine ratio (IPC) at 3, 6 and 12 months. We define renal response as a decrease by at least 30% of proteinuria and/or stabilization or improvement of FG. We consider that an anti-inflammatory response is a decrease of more than 50% in serum amyloid protein (PSA) and/or C-reactive protein (CRP).

RESULTS

We collected 3 cases of patients with histologically proven AA amyloidosis treated with TCZ (2 men; 1 woman; aged 55, 74 and 75 years). The follow-up was 13, 14 and 75 months. FG was stabilized in two patients. The third patient remained on hemodialysis during follow-up, although with excellent control of her underlying inflammatory disease. In all three cases, reduced PSA and CRP were observed. There have been no adverse events.

CONCLUSIONS

The TCZ may be an effective and safe option in treatment of AA amyloidosis with renal involvement. Our results position it as an interesting therapeutic option to consider in these cases, although prospective studies would be necessary to evaluate the global role of TCZ in AA amyloidosis.

Machine learning analyses of antibody somatic mutations predict immunoglobulin light chain toxicity

In systemic light chain amyloidosis (AL), pathogenic monoclonal immunoglobulin light chains (LC) form toxic aggregates and amyloid fibrils in target organs. Prompt diagnosis is crucial to avoid permanent organ damage, but delayed diagnosis is common because symptoms usually appear only after strong organ involvement. Here we present LICTOR, a machine learning approach predicting LC toxicity in AL, based on the distribution of somatic mutations acquired during clonal selection. LICTOR achieves a specificity and a sensitivity of 0.82 and 0.76, respectively, with an area under the receiver operating characteristic curve (AUC) of 0.87. Tested on an independent set of 12 LCs sequences with known clinical phenotypes, LICTOR achieves a prediction accuracy of 83%. Furthermore, we are able to abolish the toxic phenotype of an LC by in silico reverting two germline-specific somatic mutations identified by LICTOR, and by experimentally assessing the loss of in vivo toxicity in a Caenorhabditis elegans model. Therefore, LICTOR represents a promising strategy for AL diagnosis and reducing high mortality rates in AL.

Apolipoprotein AI amyloid deposits in the ligamentum flavum in patients with lumbar spinal canal stenosis

Amyloidosis is a protein-misfolding disease characterised by insoluble amyloid deposits in the extracellular space of various organs and tissues, such as the brain, heart, kidneys, and ligaments. We previously reported the frequent occurrence of amyloid deposits in the ligament flavum in the presence of lumbar spinal canal stenosis (LSCS), which is a common spinal disorder in older individuals. Our earlier clinicopathological studies revealed that amyloid deposits derived from transthyretin (TTR) were involved in the pathogenesis of LSCS. ATTR amyloid was the most common form in the ligamentum flavum, but amyloid deposits that were not identified still existed in more than 50% of patients with LSCS. In this study, we found apolipoprotein AI (AApoAI) amyloid deposits in the ligamentum flavum of patients with LSCS. The deposits occurred in 12% of patients with LSCS. Biochemical studies revealed that the amyloid deposits consisted mainly of full-length ApoAI. As a notable finding, the lumbar ligamentum flavum of patients who had LSCS with double-positive amyloid deposits-positive for both ATTR and AApoAI-was significantly thicker than that of patients who had LSCS with single-positive-that is, positive for either ATTR or AApoAI-amyloid deposits. We thus suggest that lumbar AApoAI amyloid formation may enhance the pathological changes of lumbar ATTR amyloidosis in patients with LSCS.

Lung cancer combined with diffuse peritoneal and mesenteric amyloidosis detected on 18F-FDG PET/CT: A case report

RATIONALE

Amyloidosis is a heterogeneous group of diseases characterized by extracellular deposition of amyloid fibrils. Lung carcinoma is rarely reported to be associated with AA amyloidosis. With regard to the manifestation of amyloidosis infiltrating organs, most of the cases focus on the heart, liver, kidneys, and peripheral nervous system. Amyloidosis with diffuse abdominal involvement in combination with pulmonary squamous cell carcinoma carcinoma is an exceptionally rare occurrence.

PATIENT CONCERNS

A 70-year-old man was admitted to hospital for a 2-month history of repeated cough, low grade fever, hemoptysis and left back shoulder pain, which was not relieved by nonsteroid anti-inflammatory drugs. Meanwhile, he complained of intermittent diffuse abdominal discomfort and chronic persistent constipation.

DIAGNOSES

The patient was diagnosed with poorly differentiated lung squamous cell carcinoma and diffuse peritoneal and mesenteric amyloidosis based on the pathological biopsy.

INTERVENTIONS

The patient received surgery and chemotherapy for lung tumor. He did not receive any treatment against amyloidosis.

OUTCOMES

The patient died of a severe respiratory infection.

LESSONS

This case indicates that lung carcinoma is suspected to play a causative role in the development of amyloidosis. In addition, amyloidosis should be considered in the differential diagnosis in cases in which diffuse greater omentum, peritoneal, and mesenteric calcifications on 18F-2-fluoro-2-deoxy-D-glucose(18F-FDG) photon emission computed tomography (PET/CT).

Unusual case of amyloidosis presenting as a jejunal mass

Amyloidosis constitutes a heterogeneous group of disorders of protein misfolding that can involve different organ systems. The disease can occur either in a systemic or localised manner that is well known to involve the gastrointestinal (GI) tract. GI amyloidosis can present with a wide range of symptoms including diarrhoea, bleeding and obstruction. This case illustrates a patient with localised jejunal amyloid light chain disease that was diagnosed serendipitously during a workup for haematuria. Our patient was otherwise asymptomatic, but this case underscores the importance of considering amyloidosis as a possible cause of isolated masses of the small intestine.

The Expression of Chemokines Is Downregulated in a Pre-Clinical Model of TTR V30M Amyloidosis

Inflammation is a hallmark of several neurodegenerative disorders including hereditary amyloidogenic transthyretin amyloidosis (ATTRv). ATTRv is an autosomal dominant neurodegenerative disorder with extracellular deposition of mutant transthyretin (TTR) aggregates and fibrils, particularly in nerves and ganglia of the peripheral nervous system. Nerve biopsies from ATTRv patients show increased cytokine production, but interestingly no immune inflammatory cellular infiltrate is observed around TTR aggregates. Here we show that as compared to Wild Type (WT) animals, the expression of several chemokines is highly downregulated in the peripheral nervous system of a mouse model of the disease. Interestingly, we found that stimulation of mouse Schwann cells (SCs) with WT TTR results in the secretion of several chemokines, a process that is mediated by toll-like receptor 4 (TLR4). In contrast, the secretion of all tested chemokines is compromised upon stimulation of SCs with mutant TTR (V30M), suggesting that V30M TTR fails to activate TLR4 signaling. Altogether, our data shed light into a previously unappreciated mechanism linking TTR activation of SCs and possibly underlying the lack of inflammatory response observed in the peripheral nervous system of ATTRv patients.

Pathophysiology and Therapeutic Approaches to Cardiac Amyloidosis

Often considered a rare disease, cardiac amyloidosis is increasingly recognized by practicing clinicians. The increased rate of diagnosis is in part due the aging of the population and increasing incidence and prevalence of cardiac amyloidosis with advancing age, as well as the advent of noninvasive methods using nuclear scintigraphy to diagnose transthyretin cardiac amyloidosis due to either variant or wild type transthyretin without a biopsy. Perhaps the most important driver of the increased awareness is the elucidation of the biologic mechanisms underlying the pathogenesis of cardiac amyloidosis which have led to the development of several effective therapies with differing mechanisms of actions. In this review, the mechanisms underlying the pathogenesis of cardiac amyloidosis due to light chain (AL) or transthyretin (ATTR) amyloidosis are delineated as well as the rapidly evolving therapeutic landscape that has emerged from a better pathophysiologic understanding of disease development.

Pulmonary amyloidosis mimicking interstitial lung disease and malignancy - A case series with a review of a pulmonary patterns

BACKGROUND

Amyloidosis is an uncommon condition, which results from accumulation of misfolded extracellular insoluble protein in tissues and organs of the body, causing its damage and dysfunction. Histologically, after staining with Congo red, the amyloid deposits show an apple-green birefringence under polarized light microscope. Amyloidosis can affect all organ systems and is classified into hereditary or acquired, localized or systemic. Respiratory involvement occurs in 50% of the patients with amyloidosis and it may take tracheobronchial, nodular parenchymal, diffuse alveolar septal and lymphatic forms.

METHODS

We report four cases of pulmonary amyloidosis. A female patient with localized form of tracheobronchial and nodular parenchymal pulmonary amyloidosis, which was initially misdiagnosed as sarcoidosis. A male patient who was referred to our department for further evaluation of multiple tumors in lungs accompanied by mediastinal lymphadenopathy, liver and peritoneal tumors. A male patient with suspect of lung malignancy. A male patient with diagnosed idiopathic pulmonary fibrosis and the possibility of malignancy.

RESULTS

All the diagnoses were established by demonstration of amyloid protein in tissue specimens obtained in transbronchial or open lung biopsies.

CONCLUSIONS

Due to its nonspecific clinical and radiological findings, amyloidosis can often mimic other diseases and should be considered as one of the differential diagnoses. In order to confirm the diagnosis, proving the presence of amyloid deposition with positive Congo red staining in respiratory specimen is mandatory.

Renal transplant outcomes in amyloidosis

BACKGROUND

Outcomes after renal transplantation have traditionally been poor in systemic amyloid A (AA) amyloidosis and systemic light chain (AL) amyloidosis, with high mortality and frequent recurrent disease. We sought to compare outcomes with matched transplant recipients with autosomal dominant polycystic kidney disease (ADPKD) and diabetic nephropathy (DN), and identify factors predictive of outcomes.

METHODS

We performed a retrospective cohort study of 51 systemic AL and 48 systemic AA amyloidosis patients undergoing renal transplantation. Matched groups were generated by propensity score matching. Patient and death-censored allograft survival were compared via Kaplan-Meier survival analyses, and assessment of clinicopathological features predicting outcomes via Cox proportional hazard analyses.

RESULTS

One-, 5- and 10-year death-censored unadjusted graft survival was, respectively, 94, 91 and 78% for AA amyloidosis, and 98, 93 and 93% for AL amyloidosis; median patient survival was 13.1 and 7.9 years, respectively. Patient survival in AL and AA amyloidosis was comparable to DN, but poorer than ADPKD [hazard ratio (HR) = 3.12 and 3.09, respectively; P < 0.001]. Death-censored allograft survival was comparable between all groups. In AL amyloidosis, mortality was predicted by interventricular septum at end diastole (IVSd) thickness >12 mm (HR = 26.58; P = 0.03), while survival was predicted by haematologic response (very good partial or complete response; HR = 0.07; P = 0.018). In AA amyloidosis, recurrent amyloid was associated with elevated serum amyloid A concentration but not with outcomes.

CONCLUSIONS

Renal transplantation outcomes for selected patients with AA and AL amyloidosis are comparable to those with DN. In AL amyloidosis, IVSd thickness and achievement of deep haematologic response pre-transplant profoundly impact patient survival.

Trypsin Induced Degradation of Amyloid Fibrils

Proteolytic enzymes are known to be involved in the formation and degradation of various monomeric proteins, but the effect of proteases on the ordered protein aggregates, amyloid fibrils, which are considered to be extremely stable, remains poorly understood. In this work we study resistance to proteolytic degradation of lysozyme amyloid fibrils with two different types of morphology and beta-2-microglobulun amyloids. We showed that the proteolytic enzyme of the pancreas, trypsin, induced degradation of amyloid fibrils, and the mechanism of this process was qualitatively the same for all investigated amyloids. At the same time, we found a dependence of efficiency and rate of fibril degradation on the structure of the amyloid-forming protein as well as on the morphology and clustering of amyloid fibrils. It was assumed that the discovered relationship between fibrils structure and the efficiency of their degradation by trypsin can become the basis of a new express method for the analysis of amyloids polymorphism. Unexpectedly lower resistance of both types of lysozyme amyloids to trypsin exposure compared to the native monomeric protein (which is not susceptible to hydrolysis) was attributed to the higher availability of cleavage sites in studied fibrils. Another intriguing result of the work is that the cytotoxicity of amyloids treated with trypsin was not only failing to decline, but even increasing in the case of beta-2-microglobulin fibrils.

Gastric perforation caused by secondary systemic amyloidosis

Amyloid A amyloidosis secondary to chronic inflammation involves systemic organs and tissues, including the gastrointestinal tract. In the present case, massive amyloid deposit caused gastric perforation. IgM co-deposition in the glomeruli was another finding of note.

The long and winding road to target protein misfolding in cardiovascular diseases

BACKGROUND

In the last decades, cardiovascular diseases (CVD) have remained the first leading cause of mortality and morbidity in the world. Although several therapeutic approaches have been introduced in the past, the development of novel treatments remains an important research goal, which is hampered by the lack of understanding of key mechanisms and targets. Emerging evidences in recent years indicate the involvement of misfolded proteins aggregation and the derailment of protein quality control in the pathogenesis of cardiovascular diseases. Several potential interventions targeting protein quality control have been translated from the bench to the bedside to effectively employ the misfolded proteins as promising therapeutic targets for cardiac diseases, but with trivial results.

DESIGN

In this review, we describe the recent progresses in preclinical and clinical studies of protein misfolding and compromised protein quality control by selecting and reporting studies focusing on cardiovascular diseases including cardiomyopathies, cardiac amyloidosis, atherosclerosis, atrial fibrillation and thrombosis.

RESULTS

In preclinical models, modulators of several molecular targets (eg heat shock proteins, unfolded protein response, ubiquitin protein system, autophagy and histone deacetylases) have been tested in various conditions with promising results although lacking an adequate transition towards clinical setting.

CONCLUSIONS

At present, no therapeutic strategies have been reported to attenuate proteotoxicity in patients with CVD due to a lack of specific biomarkers for pinpointing upstream events in protein folding defects at a subclinical stage of the diseases requiring an intensive collaboration between basic scientists and clinicians.

Methods to study the structure of misfolded protein states in systemic amyloidosis

Systemic amyloidosis is defined as a protein misfolding disease in which the amyloid is not necessarily deposited within the same organ that produces the fibril precursor protein. There are different types of systemic amyloidosis, depending on the protein constructing the fibrils. This review will focus on recent advances made in the understanding of the structural basis of three major forms of systemic amyloidosis: systemic AA, AL and ATTR amyloidosis. The three diseases arise from the misfolding of serum amyloid A protein, immunoglobulin light chains or transthyretin. The presented advances in understanding were enabled by recent progress in the methodology available to study amyloid structures and protein misfolding, in particular concerning cryo-electron microscopy (cryo-EM) and nuclear magnetic resonance (NMR) spectroscopy. An important observation made with these techniques is that the structures of previously described in vitro formed amyloid fibrils did not correlate with the structures of amyloid fibrils extracted from diseased tissue, and that in vitro fibrils were typically more protease sensitive. It is thus possible that ex vivo fibrils were selected in vivo by their proteolytic stability.

Clinical Mass Spectrometry Approaches to Myeloma and Amyloidosis

The diagnosis of myeloma and other plasma cell disorders has traditionally been done with the aid of electrophoretic methods, whereas amyloidosis has been characterized by immunohistochemistry. Mass spectrometry has recently been established as an alternative to these traditional methods and has been proved to bring added benefit for patient care. These newer mass spectrometry-based methods highlight some of the key advantages of modern proteomic methods and how they can be applied to the routine care of patients.

Systemic AL amyloidosis presenting with diffuse alveolar septal involvement and respiratory failure: a case report and review of the literature

Background

Amyloidosis is the extracellular deposition of amyloid fibril protein in any tissue or organ. The clinical manifestations of pulmonary amyloidosis are variable and without specific symptoms. We report a rare case of diffuse alveolar septal amyloidosis which is an extremely rare pattern of involvement, with a very poor prognosis, to improve our understanding of the disease.

Case presentation

A 27-year-old man complained of shortness of breath and cyanosis. High-resolution computed tomography revealed diffuse ground-glass opacifications with interlobular septal thickening in both lungs. The immune-histochemistry showed monoclonal lambda light chains. This case also showed nephrotic syndrome and cardiac arrhythmia, suggesting an involvement of the kidney and the heart. Diagnosis: The diagnosis was finally established by tru-cut transthoracic sonar guided lung biopsy (TSLB), and histological examination revealed Congo red-positive amorphous eosinophilic deposits in the alveolar sept. Interventions: The patient was admitted to a respiratory intensive care unit and put on non-invasive ventilation, then discharged on domiciliary oxygen therapy, and started treatment with chemotherapy melphalan 2 mg daily plus prednisone 60 mg daily immediately after the result of histopathology. Outcomes: Three months after treatment, dyspnea and hypoxemia improved, and he continued treatment. The patient was in a good clinical condition after 10 months of follow-up, but he died suddenly.

Conclusion

As it is difficult to distinguish diffuse alveolar septal amyloidosis from other interstitial and granulomatous lung diseases because of their similar symptoms and imaging findings, thus, transthoracic sonar guided lung biopsy and histological examination is very important in the diagnosis of diffuse alveolar septal amyloidosis.

Poor right ventricular function is associated with impaired exercise capacity and ventilatory efficiency in transthyretin cardiac amyloid patients

CardioPulmonary Exercise Test (CPET) is the gold standard to evaluate functional capacity in patients at high risk of heart failure (HF). Few studies with a limited number of subjects and conflicting results, analyzed the role of CPET in patients with systemic amyloidosis. Aims of our study were the assessment of the response to exercise in patients with Transthyretin amyloid (ATTR) cardiomyopathy (CA), and the correlation of clinical, biohumoral and echocardiographic parameters with CPET parameters, such as VO₂ peak and VE/VCO₂ slope. From February 2018 to March 2019, 72 cardiac ATTR patients were prospectively enrolled and underwent a complete clinical, biohumoral, echocardiographic and CPET assessment. All patients completed the exercise stress test protocol, without any adverse event. At CPET, they achieved a mean VO₂ peak of 14 mL/Kg/min and a mean VE/VCO₂ slope of 31. The blood pressure response to exercise was inadequate in 26 (36%) patients (flat in 25 and hypotensive in 1), while 49/72 patients (69%) showed an inadequate heart rate recovery. In multivariate analysis, s' tricuspidalic was the only independent predictor of VO₂ peak, while in the two test models performed to avoid collinearity, both TAPSE and s' tricuspidalic were the strongest independent predictors of VE/VCO₂ slope. Our data demonstrate the role of right ventricular function as an independent predictor of exercise capacity and ventilatory efficiency in ATTR. In CPET evaluation, a significant proportion of patients presented an abnormal arterial pressure response and heart rate variation to exercise.

Comparison of the current renal staging, progression and response criteria to predict renal survival in AL amyloidosis using a Mayo cohort

Three sets of criteria (International Society of Amyloidosis [ISA], Palladini and Kastritis) were independently developed for staging, progression and response criteria to predict renal survival in patients with AL amyloidosis. We evaluated these criteria using a cohort of 495 newly diagnosed AL amyloidosis patients with renal involvement using time to event competing risk analysis at baseline, 3, 6 and 12 months after treatment. Only Palladini and Kastritis had a staging system and both predicted a higher risk of end stage renal disease (ESRD) in the stage III vs stage I patients but only the Palladini model was predictive for stage II patients. At 3 months, risk of ESRD was significantly higher for Palladini and ISA renal progression (hazard ratio [HR] 2.8 [95% CI: 1.5-5.3, p = .001] and 2.5 [CI: 1.4-4.6, p = .004, respectively]), but renal response was not significantly protective; conversely, the risk of ESRD was not significantly higher for the Kastritis renal progression, but was significantly protective for the Kastritis renal responders (HR 0.38 [95% CI: 0.17-0.84], p = .017). Both progression and response with ISA, Palladini and Kastritis criteria were predictive of ESRD at 6 months and 12 months. While the Palladini staging criteria at baseline, and the ISA and Palladini criteria for progression at 3 months performed better than the Kastritis criteria at baseline and 3 months post-treatment, the Kastritis criteria performed better for response 3 months after treatment. All three sets of criteria performed well at and after 6 months post-treatment. These differences are important when choosing endpoints for clinical trials.

High-Density Lipoproteins and the Kidney

Dyslipidemia is a typical trait of patients with chronic kidney disease (CKD) and it is typically characterized by reduced high-density lipoprotein (HDL)-cholesterol(c) levels. The low HDL-c concentration is the only lipid alteration associated with the progression of renal disease in mild-to-moderate CKD patients. Plasma HDL levels are not only reduced but also characterized by alterations in composition and structure, which are responsible for the loss of atheroprotective functions, like the ability to promote cholesterol efflux from peripheral cells and antioxidant and anti-inflammatory proprieties. The interconnection between HDL and renal function is confirmed by the fact that genetic HDL defects can lead to kidney disease; in fact, mutations in apoA-I, apoE, apoL, and lecithin–cholesterol acyltransferase (LCAT) are associated with the development of renal damage. Genetic LCAT deficiency is the most emblematic case and represents a unique tool to evaluate the impact of alterations in the HDL system on the progression of renal disease. Lipid abnormalities detected in LCAT-deficient carriers mirror the ones observed in CKD patients, which indeed present an acquired LCAT deficiency. In this context, circulating LCAT levels predict CKD progression in individuals at early stages of renal dysfunction and in the general population. This review summarizes the main alterations of HDL in CKD, focusing on the latest update of acquired and genetic LCAT defects associated with the progression of renal disease.

Primary localized gastric amyloidosis: A scoping review of the literature from clinical presentations to prognosis

Localized gastric amyloidosis (LGA) is a rare disease characterized by abnormal extracellular deposition of amyloid protein restricted to the stomach and it is confirmed by positive results of Congo red staining. Over decades, only a few cases have been reported and studies or research focusing on it are few. Although LGA has a low incidence, patients may suffer a lot from it and require proper diagnosis and management. However, the pathology of LGA remains unknown and no overall review of LGA from its presentations to its prognosis has been published. Patients with LGA are often asymptomatic or manifest atypical symptoms, making it difficult to differentiate from other gastrointestinal diseases. Here, we report the case of a 70-year-old woman with LGA and provide an overview of case reports of LGA available to us. Based on that, we conclude current concepts of clinical manifestations, diagnosis, treatment, and prognosis of LGA, aiming at providing a detailed diagnostic procedure for clinicians and promoting the guidelines of LGA. In addition, a few advanced technologies applied in amyloidosis are also discussed in this review, aiming at providing clinicians with a reference of diagnostic process. With this review, we hope to raise awareness of LGA among the public and clinicians.

Recent advances in the diagnosis and management of amyloid cardiomyopathy

Amyloidosis is a disorder characterized by misfolded precursor proteins that form depositions of fibrillar aggregates with an abnormal cross-beta-sheet conformation, known as amyloid, in the extracellular space of several tissues. Although there are more than 30 known amyloidogenic proteins, both hereditary and non-hereditary, cardiac amyloidosis (CA) typically arises from either misfolded transthyretin (ATTR amyloidosis) or immunoglobulin light-chain aggregation (AL amyloidosis). Its prevalence is more common than previously thought, especially among patients with heart failure and preserved ejection fraction (HFpEF) and aortic stenosis. If there is a clinical suspicion of CA, focused echocardiography, laboratory screening for the presence of a monoclonal protein (serum and urinary electrophoresis with immunofixation and serum free light-chain ratio), and cardiac scintigraphy with 99mtechnetium-labeled bone-tracers are sensitive and specific initial diagnostic tests. In some cases, more advanced/invasive techniques are necessary and, in the last several years, treatment options for both AL CA and ATTR CA have rapidly expanded. It is important to note that the aims of therapy are different. Systemic AL amyloidosis requires treatment targeted against the abnormal plasma cell clone, whereas therapy for ATTR CA must be targeted to the production and stabilization of the TTR molecule. It is likely that a multistep treatment approach will be optimal for both AL CA and ATTR CA. Additionally, treatment of CA includes the management of restrictive cardiomyopathy with preserved or reduced ejection fraction in addition to treating the amyloid deposition. Future studies are necessary to define optimal management strategies for AL CA and ATTR CA and confirm cardiac response to therapy.

Influence of Ventricular Wringing on the Preservation of Left Ventricular Ejection Fraction in Cardiac Amyloidosis

BACKGROUND

The purpose of this work was to determine the influence of myocardial wringing on ventricular function in patients with cardiac amyloidosis (CA).

METHODS

Fifteen healthy volunteers (group 1) and 34 patients with CA (17 with left ventricular ejection fractions [LVEFs] ≥ 53% [group 2] and 17 with LVEFs < 53% [group 3]) were evaluated using two-dimensional speckle-tracking echocardiography. A control group of mass-matched patients (n = 20) with left ventricular (LV) hypertrophy and LVEFs ≥ 53% was also included. Longitudinal strain (LS), circumferential strain, and LV twist and torsion were calculated. Deformation index (DefI), a new parameter of wringing, calculated as twist/LS, that takes into account actions that occur simultaneously during LV systole (i.e., longitudinal shortening and twist), was evaluated. Torsional and wringing parameters were calculated according to LVEF.

RESULTS

Lower global values of LS and circumferential strain were observed among patients with CA (LS: group 1, -20.6 ± 2.5%; group 2, -11.6 ± 4.1%; group 3, -9.0 ± 3.1%; circumferential strain: group 1, -22.7 ± 4.9%; group 2, -14.4 ± 8.0%; group 3, -13.6 ± 3.8%; P < .001 for both). Torsion did not vary between group 2 and group 1 (2.5 ± 1.1°/cm vs 2.7 ± 0.8°/cm, P = NS). In contrast, DefI was greater in group 2 than in group 1 (-1.8 ± 0.8°/% vs -1.0 ± 0.3°/%, P < .01). Torsion and DefI were lower in group 3 (1.2 ± 0.7°/cm and -1.1 ± 0.6°/%, respectively, P < .001 for both) than in group 2. DefI was similar in patients with LV hypertrophy (-1.7 ± 0.6°/%, P = NS) and group 2.

CONCLUSIONS

In patients with CA, preservation of LVEF depends on greater ventricular wringing. DefI, a parameter that integrates the twist and the simultaneous longitudinal shortening of the left ventricle, is a more accurate indicator of the efficacy of this mechanism.

Prognostic Utility of Echocardiographic Atrial and Ventricular Strain Imaging in Patients With Cardiac Amyloidosis

OBJECTIVES

The prognostic value of echocardiographic atrial and ventricular strain imaging in patients with biopsy-proven cardiac amyloidosis was assessed.

BACKGROUND

Although left ventricular global longitudinal strain (GLS) is known to be predictive of outcome, the additive prognostic value of left (LA), right atrial (RA), and right ventricular (RV) strain is unclear.

METHODS

One hundred thirty-six patients with cardiac amyloidosis and available follow-up data were studied by endomyocardial biopsy, noncardiac biopsy with supportive cardiac imaging, or autopsy confirmation. One hundred nine patients (80%) had light-chain, 23 (17%) had transthyretin, and 4 (3%) had amyloid A type cardiac amyloidosis. GLS, RV free wall strain, peak longitudinal LA strain, and peak longitudinal RA strain were measured from apical views. Clinical and routine echocardiographic data were compared. All-cause mortality was followed (median 5 years).

RESULTS

Strain data were feasible for GLS in 127 (93%), LA strain in 119 (88%), RA strain in 117 (86%), and RV strain in 102 (75%). Strain values from all 4 chambers were significantly associated with survival. Hazard ratio (HR) and 95% confidence interval (CI) for low median strain values were as follows: GLS, HR: 2.3; 95% CI: 1.3 to 3.8 (p < 0.01); LA strain, HR: 7.5; 95% CI: 3.8 to 14.7 (p < 0.001); RA strain, HR: 3.5; 95% CI: 2.0 to 6.2 (p < 0.001); and RV free wall strain, HR: 2.8; 95% CI: 1.5 to 5.1 (p < 0.001). Peak longitudinal LA strain and RV strain remained independently associated with survival in multivariable analysis. Peak LA strain had the strongest association with survival (p < 0.001), and LA strain combined with GLS and RV free wall strain had the highest prognostic value (p < 0.001).

CONCLUSIONS

Strain data from all 4 chambers had important prognostic associations with survival in patients with biopsy-confirmed cardiac amyloidosis. Peak longitudinal LA strain was particularly associated with prognosis. Atrial and ventricular strain have promise for clinical utility.

Biflavonoid-Induced Disruption of Hydrogen Bonds Leads to Amyloid-β Disaggregation

Deposition of amyloid β (Aβ) fibrils in the brain is a key pathologic hallmark of Alzheimer’s disease. A class of polyphenolic biflavonoids is known to have anti-amyloidogenic effects by inhibiting aggregation of Aβ and promoting disaggregation of Aβ fibrils. In the present study, we further sought to investigate the structural basis of the Aβ disaggregating activity of biflavonoids and their interactions at the atomic level. A thioflavin T (ThT) fluorescence assay revealed that amentoflavone-type biflavonoids promote disaggregation of Aβ fibrils with varying potency due to specific structural differences. The computational analysis herein provides the first atomistic details for the mechanism of Aβ disaggregation by biflavonoids. Molecular docking analysis showed that biflavonoids preferentially bind to the aromatic-rich, partially ordered N-termini of Aβ fibril via the π–π interactions. Moreover, docking scores correlate well with the ThT EC₅₀ values. Molecular dynamic simulations revealed that biflavonoids decrease the content of β-sheet in Aβ fibril in a structure-dependent manner. Hydrogen bond analysis further supported that the substitution of hydroxyl groups capable of hydrogen bond formation at two positions on the biflavonoid scaffold leads to significantly disaggregation of Aβ fibrils. Taken together, our data indicate that biflavonoids promote disaggregation of Aβ fibrils due to their ability to disrupt the fibril structure, suggesting biflavonoids as a lead class of compounds to develop a therapeutic agent for Alzheimer’s disease.

Quinoline yellow dye stimulates whey protein fibrillation via electrostatic and hydrophobic interaction: A biophysical study

Amyloid fibril formation of proteins is associated with a number of neurodegenerative diseases. Several small molecules can accelerate the amyloid fibril formation in vitro and in vivo. However, the molecular mechanism of amyloid fibrillation is still unclear. In this study, we investigated how the food dye quinoline yellow (QY) induces amyloid fibrillation in α-lactalbumin (α-LA), a major whey protein, at pH 2.0. We used several spectroscopy techniques and a microscopy technique to explore how QY provokes amyloid fibrillation in α-LA. From turbidity and Rayleigh light scattering experiments, we found that QY promotes α-LA aggregation in a concentration-dependent manner; the optimal concentration for α-LA aggregation was 0.15 to 10.00 mM. Below 0.1 mM, no aggregation occurred. Quinoline yellow-induced aggregation was a rapid process that escaped the lag phase, but it depended on the concentrations of both α-LA and QY. We also demonstrated that aggregation switched the secondary structure of α-LA from α-helices to cross-β-sheets. We then confirmed the amyloid-like structure of aggregated α-LA by transmission electron microscopy measurements. Molecular docking and simulation confirmed the stability of the α-LA-QY complex due to the formation of 1 hydrogen bond with Lys99 and 2 electrostatic interactions with Arg70 and Lys99, along with hydrophobic interactions with Leu59 and Tyr103. This study will aid in our understanding of how small molecules induce aggregation of proteins inside the stomach (low pH) and affect the digestive process.

Using digital whole-slide images to evaluate renal amyloid deposition and its association with clinical features and outcomes of AL amyloidosis

BACKGROUND

Few data are available quantifying the proportion of amyloid deposition in renal biopsy specimens. The aim of the study is to investigate the correlation between the proportion of amyloid deposition in renal biopsy and clinical characteristics of Chinese patients with immunoglobulin light-chain amyloidosis (AL amyloidosis).

METHODS

259 patients diagnosed with renal AL amyloidosis between 2003 and 2015 were studied retrospectively. We developed a digital, automated quantification method to evaluate amyloid deposits in glomeruli, vessels and interstitium on digital whole-slide images (WSIs). The associations between the proportion of amyloid-positive area in the renal biopsy and clinical manifestations were analyzed.

RESULTS

The proportion (%) of amyloid-positive area in glomeruli, vessels, interstitium and the whole renal tissue were 11.81 ± 11.38, 14.14 ± 14.05, 3.34 ± 5.36 and 4.25 ± 5.77, respectively. The proportion of amyloid deposition in glomeruli, vessels and interstitium was positively correlated with serum creatinine (Scr), estimated glomerular filtration rate (eGFR) and urinary retinol binding protein (RBP). The proportion of glomerular amyloid deposition, age, urinary N-acetyl-b-D-glucosaminidase (NAG) and urinary RBP could independently predict the risk for overall death. The proportion (%) of amyloid-positive area in blood vessels, interstitium and the whole renal tissue, Scr, and urinary RBP were independent risk factors associated with renal survival.

CONCLUSION

A novel digital analysis algorithm was firstly developed to quantify the proportion of amyloid deposits in renal tissues based on digital WSIs. The degree and localization of amyloid deposits in the kidney evaluated by digital WSIs may have predictive value in assessing risk of outcome of AL amyloidosis.

Comparison of AA Amyloid Fibril Morphology and Serum Amyloid A Gene Sequence in 5 Animal Species

Amyloid fibrils are characterized by a linear morphology and a cross-β structure. Polymorphic and multiple fibril morphologies can be found when amyloid fibrils are extracted from amyloid-laden tissue. In this study, we report on the purification and transmission electron microscopic analysis of amyloid fibrils from 5 different animal species (mouse, cow, goat, dog, and camel) with AA amyloidosis. The results show that amyloid fibrils had a linear morphology with a cross-structure and irregular length in vivo. Although the fibrils from these different species showed highly similar conformations, there were significant differences in fibril width and crossover distance. We analyzed the sequences of homologous amyloid proteins and serum amyloid A, an evolutionarily conserved protein and a major amyloid precursor. We found 78.23% homology between the most distant amyloid proteins. The findings suggested similar fibril width and crossover distance in different animal species that displayed high homology of amyloid protein sequences. Dog and camel, as well as goat and cow, showed high genetic homology and similar fibril morphology. These data indicate that the fibrils from different animal species have similar genetic homology and morphology, which may provide a better understanding of the pathogenesis of amyloidosis.

Primary isolated amyloidosis in the extraocular muscle as a rare cause of ophthalmoplegia: A case report and literature review

Purpose

To report a case of external ophthalmoplegia due to an uncommon form of amyloidosis exclusively affecting the lateral rectus muscle, and to discuss the clinical manifestation, diagnostic challenges, and management pitfalls of isolated amyloidosis in the extraocular muscle.

Observations

A 64-year-old woman presented with diplopia in her left gaze lasting for six months. She had orthophoria in the primary position and abduction limitation in the left eye. Routine laboratory examinations were unremarkable. Orbital magnetic resonance imaging showed fusiform enlargement of the left lateral rectus muscle, without tendon involvement. Extraocular muscle biopsy was recommended to make a diagnosis, which revealed amyloid deposition in the lateral rectus muscle. A systemic work-up showed no evidence of systemic amyloidosis. Therefore, a diagnosis of primary isolated amyloidosis was made. Orthophoria in the primary position and diplopia in the lateral gaze persisted at the six-month follow-up.

Conclusions and importance

Atypical extraocular muscle enlargement should alert clinicians to the need for tissue biopsy to identify uncommon etiologies, such as amyloidosis. There are no pathognomonic or radiological features to distinguish localized from systemic amyloidosis. Therefore, if amyloidosis of the extraocular muscles is diagnosed, a systemic work-up is needed to rule out systemic amyloidosis, which is potentially life-threatening.

Regional Amyloid Burden Differences Evaluated Using Quantitative Cardiac MRI in Patients with Cardiac Amyloidosis

Objective

This study aimed to investigate the regional amyloid burden and myocardial deformation using T1 mapping and strain values in patients with cardiac amyloidosis (CA) according to late gadolinium enhancement (LGE) patterns.

Materials and Methods

Forty patients with CA were divided into 2 groups per LGE pattern, and 15 healthy subjects were enrolled. Global and regional native T1 and T2 mapping, extracellular volume (ECV), and cardiac magnetic resonance (CMR)-feature tracking strain values were compared in an intergroup and interregional manner.

Results

Of the patients with CA, 32 had diffuse global LGE (group 2), and 8 had focal patchy or no LGE (group 1). Global native T1, T2, and ECV were significantly higher in groups 1 and 2 than in the control group (native T1: 1384.4 ms vs. 1466.8 ms vs. 1230.5 ms; T2: 53.8 ms vs. 54.2 ms vs. 48.9 ms; and ECV: 36.9% vs. 51.4% vs. 26.0%, respectively; all, p < 0.001). Basal ECV (53.7%) was significantly higher than the mid and apical ECVs (50.1% and 50.0%, respectively; p < 0.001) in group 2. Basal and mid peak radial strains (PRSs) and peak circumferential strains (PCSs) were significantly lower than the apical PRS and PCS, respectively (PRS, 15.6% vs. 16.7% vs. 26.9%; and PCS, −9.7% vs. −10.9% vs. −15.0%; all, p < 0.001). Basal ECV and basal strain (2-dimensional PRS) in group 2 showed a significant negative correlation (r = −0.623, p < 0.001). Group 1 showed no regional ECV differences (basal, 37.0%; mid, 35.9%; and apical, 38.3%; p = 0.184).

Conclusion

Quantitative T1 mapping parameters such as native T1 and ECV may help diagnose early CA. ECV, in particular, can reflect regional differences in the amyloid deposition in patients with advanced CA, and increased basal ECV is related to decreased basal strain. Therefore, quantitative CMR parameters may help diagnose CA and determine its severity in patients with or without LGE.

Serotonin and Melatonin Show Different Modes of Action on Aβ42 Protofibril Destabilization

Alzheimer's disease (AD) is associated with the aberrant self-assembly of amyloid-β (Aβ) protein into fibrillar deposits. The disaggregation of Aβ fibril is believed as one of the major therapeutic strategies for treating AD. Previous experimental studies reported that serotonin (Ser), one of the indoleamine neurotransmitters, and its derivative melatonin (Mel) are able to disassemble preformed Aβ fibrils. However, the fibril-disruption mechanisms are unclear. As the first step to understand the underlying mechanism, we investigated the interactions of Ser and Mel molecules with the LS-shaped Aβ₄₂ protofibril by performing a total of nine individual 500 ns all-atom molecular dynamics (MD) simulations. The simulations demonstrate that both Ser and Mel molecules disrupt the local β-sheet structure, destroy the salt bridges between K28 side chain and A42 COO^-, and consequently destabilize the global structure of Aβ₄₂ protofibril. The Mel molecule exhibits a greater binding capacity than the Ser molecule. Intriguingly, we find that Ser and Mel molecules destabilize Aβ₄₂ protofibril through different modes of action. Ser preferentially binds with the aromatic residues in the N-terminal region through π-π stacking interactions, while Mel binds not only with the N-terminal aromatic residues but also with the C-terminal hydrophobic residues via π-π and hydrophobic interactions. This work reveals the disruptive mechanisms of Aβ₄₂ protofibril by Ser and Mel molecules and provides useful information for designing drug candidates against AD.

A Unique Case of Combined Nodular and Tracheobronchial Amyloidosis

Amyloidosis is a heterogeneous group of diseases characterized by the extracellular deposition of misfolded proteins that can affect either systemically or locally confined to one system. Pulmonary amyloidosis is rare and can be classified into three forms according to the anatomic site of involvement: nodular pulmonary amyloidosis, tracheobronchial amyloidosis and diffuse alveolar-septal amyloidosis. The former two usually represent localized amyloid disease and the latter represents systemic disease. Typically lung parenchymal and tracheobronchial amyloidosis do not present together in localized forms of pulmonary amyloidosis. Here we report a unique case of localized pulmonary immunoglobulin light-chain amyloidosis, manifested as both parenchymal nodules and tracheobronchial amyloid deposition.