Doxycycline decreases amyloidogenic light chain-induced autophagy in isolated primary cardiac myocytes.

BACKGROUND: Immunoglobulin light chain (AL) cardiac amyloidosis is characterized by extracellular deposition of amyloid fibrils in the heart and is potentially fatal. Untreated, it manifests clinically as heart failure with a precipitous decline and a median survival of <6 months. AL cardiac amyloidosis is associated with impaired extracellular matrix homeostasis in the heart with increased matrix metalloproteinase (MMP) levels. This commmunication provides novel insights into a potential role for doxycycline, a non-selective MMP inhibitor in AL cardiac amyloidosis. METHODS/RESULTS: Adult rat ventricular myocytes stimulated with AL (obtained from cardiac amyloidosis patients) increased MMP-2 and MMP-9 activities (P < .05); the expression of autophagy marker microtubule associated protein 1 LC-3 isoform II (LC3-II) (P < .01), and the autophagy-related proteins ATG-4B (P < .05) and ATG-5 (P < .05) as compared to untreated cardiomyocytes. Doxycycline abrogated MMP activities (P < .0001) and decreased AL-induced autophagy via ATG-5 (P < .05). CONCLUSIONS: These in vitro studies demonstrated that doxycycline, in addition to inhibiting MMP, also modulated AL-induced autophagy in cardiomyocytes and provide potential insights for future therapeutic targets for AL-induced proteotoxicity. Novel therapies for cardiotoxicity and heart failure in AL cardiac amyloidosis remain an important unmet need.

Predictors of Mortality in Light Chain Cardiac Amyloidosis with Heart Failure.

Cardiac involvement in systemic amyloidosis (AL) occurs in ~50% of all AL patients. However once symptomatic heart failure develops, therapeutic options are limited thereby conferring a poor overall prognosis. The median survival is <6 months when AL patients are untreated for the underlying plasma cell dyscrasia. We thus sought to identify risk factors of increased mortality in treatment-naïve, AL cardiac amyloidosis with heart failure. Patients with biopsy-proven AL cardiac amyloid, who presented with heart failure and did not received prior AL treatment, were enrolled between 2004-2014, at the initial visit to the Amyloidosis Center at Boston University Medical Center. Routine laboratory tests, physical examination and echocardiography data were collected. There were 165 predominantly white (76.4%), and male (61%) patients, with a mean age of 61.6 ± 9.5 years. Median survival was 10.9 months (95% CI 6.2-14.7). By multivariate analysis increased relative wall thickness (RWT) [HR 6.70; 95% CI 2.45-18.30), older age (HR 1.04; 95% CI 1.01-1.06), higher New York Heart Association (NYHA) functional class (HR 1.50; 95% CI 1.02-2.2), log brain natriuretic peptide (BNP) levels (HR 1.45; 95% CI 1.15-1.81) and C-reactive protein (CRP) levels (HR 1.02; 95% CI 1.00-1.04) were significant predictors for increased mortality. In conclusion, in treatment-naïve, AL cardiac amyloidosis patients with heart failure symptoms who lack these high-risk features may have a better outcome. These findings might allow for better risk stratification although outcomes are still poor.

A phase 1/2 study of the oral proteasome inhibitor ixazomib in relapsed or refractory AL amyloidosis.

This phase 1/2 study assessed the safety, tolerability, and preliminary efficacy of the oral proteasome inhibitor (PI) ixazomib in patients with relapsed/refractory immunoglobulin light chain (AL) amyloidosis. Ixazomib was administered to adult patients with relapsed/refractory AL amyloidosis after 1 or more prior lines of therapy (including bortezomib) on days 1, 8, and 15 of 28-day cycles, for up to 12 cycles. Patients with less than partial response after 3 cycles received oral dexamethasone (40 mg, days 1-4) from cycle 4. A 3+3 dose-escalation phase was followed by 2 expansion cohorts (PI-naive and PI-exposed patients) at the maximum tolerated dose (MTD). Twenty-seven patients were enrolled: 11 during dose escalation (6 at 4.0 mg and 5 at 5.5 mg) and 16 during dose expansion (4.0 mg). Three patients experienced dose-limiting toxicities: 1 at 4.0 mg and 2 at 5.5 mg; the MTD was determined as 4.0 mg. Most common adverse events (AEs) included nausea, skin and subcutaneous tissue disorders (SSTD), diarrhea, and fatigue; grade 3 or higher AEs included dyspnea, fatigue, and SSTD. Overall, the hematologic response rate was 52% in patients treated at the MTD (n = 21). Organ responses were seen in 56% of patients (5 cardiac, 5 renal). Median hematologic progression-free survival was 14.8 months; 1-year progression-free and overall survival rates were 60% and 85%, respectively (median follow-up, 16.9 months). Weekly oral ixazomib appears to be active in patients with relapsed/refractory AL amyloidosis, with a generally manageable safety profile. The study was registered at clinicaltrials.gov as #NCT01318902 A phase 3 study is ongoing (#NCT01659658).

Longitudinal systolic strain, cardiac function improvement, and survival following treatment of light-chain (AL) cardiac amyloidosis.

AIMS: To determine whether echocardiographic longitudinal systolic strain (LS) parameters identify short-term improvement following chemotherapy for light-chain (AL) cardiac amyloidosis (CA). Among patients with CA, standard echocardiographic measures are commonly unchanged at 1 year following successful chemotherapy, despite observed reductions in cardiac biomarkers. METHODS AND RESULTS: We retrospectively identified 61 patients with AL-CA treated with high-dose melphalan or bortezomib-based regimens. Patients were classified by hematologic response at 1 year into two groups: complete response (CR; n = 18, or 30%) or non-CR (non-CR; n = 43, or 70%), and followed for 20 months. Serum free light chains (FLC), B-type natriuretic peptide (BNP), troponin I (TnI), and echocardiography including LS, were acquired at baseline and 1 year. Seven patients died (11.5%), all in the non-CR group (P < 0.01). At 1 year, while reductions were observed in BNP (44% CR, 18% non-CR) and FLC (94% CR, 73% non-CR), both P < 0.05 from baseline, there were no differences in wall thickness, EF, or diastolic function in either group. LS improved only in the CR group with notable improvement in apical to basal strain ratio (P < 0.05). Strain improvement and BNP reduction were correlated (R = 0.6, P < 0.01). Baseline global LS < -10.2% was associated with survival and proved superior to BNP and TnI. The addition of global LS to biomarkers identified the patients at highest risk of mortality. CONCLUSION: These data suggest that LS is a sensitive measure of pre-treatment cardiac functional impairment in AL-CA, can predict survival over and above that of cardiac biomarkers, and detect early cardiac functional improvement following chemotherapy.

Immunoglobulin heavy light chain test quantifies clonal disease in patients with AL amyloidosis and normal serum free light chain ratio.

BACKGROUND: Serum and urine immunofixation electrophoreses (SIFE/UIFE) are used for clonal detection in plasma cell dyscrasias, while serum free light chain (sFLC) testing provides quantitation of clonal disease. Up to 20% of patients with light chain (AL) amyloidosis may present with normal FLC ratio (FLCr). METHODS: We assessed the diagnostic, quantitative and prognostic potential of serum heavy light chain ratio (HLCr) in 199 untreated patients at initial evaluation. RESULTS: An abnormal HLCr was found in 37.2%, abnormal FLCr in 81.9% and positivity by SIFE/UIFE in 94% of patients. HLCr together with SIFE/UIFE identified clonality in 94% patients; the combination with FLCr yielded 100% sensitivity. An HLCr abnormality was significantly over-represented in normal compared to abnormal FLCr group (63.9% versus 31.3%). HLCr did not predict overall survival (OS) (log rank, p = 0.09), while an abnormal FLCr was associated with decreased OS (log rank, p = 0.03). The combined use of both ratios trended toward increased OS in the abnormal HLCr/normal FLCr group (log rank, p = 0.11; Wilcoxon, p = 0.04). On multivariate analysis, HLCr was not predictive of OS, whereas an abnormal FLCr was associated with shorter OS (HR = 1.7, p = 0.04). CONCLUSIONS: The HLC assay has potential as a supplemental test to quantify monoclonal protein in patients with normal FLCr results.

Pomalidomide and dexamethasone in the treatment of AL amyloidosis: results of a phase 1 and 2 trial.

The objectives of a phase 1/2 trial of pomalidomide with dexamethasone for the treatment of light chain (AL) amyloidosis were to determine the safety, tolerability, maximum tolerated dose (MTD), recommended phase 2 dose, and hematologic and clinical response. A 3+3 dose-escalation phase (15 patients) was followed by an expansion cohort (12 patients) enrolled at the MTD. Pomalidomide was administered at 2 and 3 mg on days 1 to 28 (cohorts 1 and 2) and 4 mg on days 1 to 21 (cohort 3) every 28 days, with weekly dexamethasone at a dose of 20 mg. Twenty-seven patients with previously treated AL were enrolled, 15 during dose escalation (6 at 2 mg, 3 at 3 mg, and 6 at 4 mg) and 12 during dose expansion (all at 4 mg). One patient experienced dose-limiting toxicity at 4 mg; the MTD was determined as 4 mg. The most common grade ≥3 drug-related adverse events included myelosuppression and fatigue. Overall, hematologic response (HR) was 50% in 24 evaluable patients. The median time to best HR was 3 cycles, and median duration of HR was 15 months. Median overall survival has not yet been reached, with a median follow-up of 17.1 months and median event-free survival of 17.8 months. This trial was registered at www.clinicaltrials.gov as #NCT01570387.

Depression and anxiety in patients with AL amyloidosis as assessed by the SF-36 questionnaire: experience in 1226 patients.

BACKGROUND: Our study examines depression and anxiety in patients with immunoglobulin light chain (AL) amyloidosis, and determines the associations between the mental health problems and patient characteristics (age, gender, race, marital status, alcohol consumption, smoking status and cardiac involvement). METHODS: Patients with AL amyloidosis who completed the 36-item Short Form General Health Survey (SF-36) during initial evaluation at a single center were studied. The SF-36 included assessments of depression, anxiety, role limitation due to emotional problems and the mental health subscale score. RESULTS: From 1226 patients with AL amyloidosis, 37.0% reported depression and 46.7% reported anxiety. Patients with cardiac amyloidosis reported more anxiety (odds ratio (OR) = 1.29, 95% confidence interval (CI) 1.03-1.61) and role limitation due to emotional problems (OR = 1.32, 95%CI 1.05-1.65). No significant association between cardiac involvement and depression was found (OR = 1.22, 95%CI 0.97-1.54). Men reported less anxiety (OR = 0.72, 95%CI 0.57-0.91). Patients ≥65 years experienced greater role limitation (OR = 1.36, 95%CI 1.08-1.71). Smokers (p = 0.019) and women (p = 0.006) scored lower on mental health subscales. CONCLUSIONS: Many patients with AL amyloidosis suffer from depression, anxiety and functional limitations. Psychiatric assessment and treatment is important, and further research is needed to clarify the long-term effects of depression and anxiety in AL amyloidosis. This current study was registered in ClinicalTrials.gov as NCT00898235.

The role of the aryl hydrocarbon receptor in the development of cells with the molecular and functional characteristics of cancer stem-like cells.

BACKGROUND: Self-renewing, chemoresistant breast cancer stem cells are believed to contribute significantly to cancer invasion, migration and patient relapse. Therefore, the identification of signaling pathways that regulate the acquisition of stem-like qualities is an important step towards understanding why patients relapse and towards development of novel therapeutics that specifically target cancer stem cell vulnerabilities. Recent studies identified a role for the aryl hydrocarbon receptor (AHR), an environmental carcinogen receptor implicated in cancer initiation, in normal tissue-specific stem cell self-renewal. These studies inspired the hypothesis that the AHR plays a role in the acquisition of cancer stem cell-like qualities. RESULTS: To test this hypothesis, AHR activity in Hs578T triple negative and SUM149 inflammatory breast cancer cells were modulated with AHR ligands, shRNA or AHR-specific inhibitors, and phenotypic, genomic and functional stem cell-associated characteristics were evaluated. The data demonstrate that (1) ALDH(high) cells express elevated levels of Ahr and Cyp1b1 and Cyp1a1, AHR-driven genes, (2) AHR knockdown reduces ALDH activity by 80%, (3) AHR hyper-activation with several ligands, including environmental ligands, significantly increases ALDH1 activity, expression of stem cell- and invasion/migration-associated genes, and accelerates cell migration, (4) a significant correlation between Ahr or Cyp1b1 expression (as a surrogate marker for AHR activity) and expression of stem cell- and invasion/migration-associated gene sets is seen with genomic data obtained from 79 human breast cancer cell lines and over 1,850 primary human breast cancers, (5) the AHR interacts directly with Sox2, a master regulator of self-renewal; AHR ligands increase this interaction and nuclear SOX2 translocation, (6) AHR knockdown inhibits tumorsphere formation in low adherence conditions, (7) AHR inhibition blocks the rapid migration of ALDH(high) cells and reduces ALDH(high) cell chemoresistance, (8) ALDH(high) cells are highly efficient at initiating tumors in orthotopic xenografts, and (9) AHR knockdown inhibits tumor initiation and reduces tumor Aldh1a1, Sox2, and Cyp1b1 expression in vivo. CONCLUSIONS: These data suggest that the AHR plays an important role in development of cells with cancer stem cell-like qualities and that environmental AHR ligands may exacerbate breast cancer by enhancing expression of these properties.

Heart Failure Resulting From Age-Related Cardiac Amyloid Disease Associated With Wild-Type Transthyretin: A Prospective, Observational Cohort Study.

BACKGROUND: Heart failure caused by wild-type transthyretin amyloidosis (ATTRwt) is an underappreciated cause of morbidity and mortality in the aging population. The aims of this study were to examine features of disease and to characterize outcomes in a large ATTRwt cohort. METHODS AND RESULTS: Over 20 years, 121 patients with ATTRwt were enrolled in a prospective, observational study. Median age at enrollment was 75.6 years (range, 62.6-87.8 years); 97% of patients were white. The median survival, measured from biopsy diagnosis, was 46.69 months (95% confidence interval, 41.95-56.77); 78% of deaths were attributable to cardiac causes. By Kaplan-Meier analysis, 5-year survival was 35.7% (95% confidence interval, 25-46). Impaired functional capacity (mean Vo2max, 13.5 mL·kg(-1)·min(-1)) and atrial fibrillation (67%) were common clinical features. Multivariate predictors of reduced survival were elevated serum brain natriuretic peptide (482 ± 337 pg/mL) and uric acid (8.2 ± 2.6 mg/dL), decreased left ventricular ejection fraction (50% median; range, 10%-70%), and increased relative wall thickness (0.75 ± 0.19). CONCLUSIONS: In this series of patients with biopsy-proven ATTRwt, poor functional capacity and atrial arrhythmias were common clinical features. Elevated brain natriuretic peptide and uric acid, decreased left ventricular ejection fraction, and increased relative wall thickness were associated with limited survival of only 35.7% at 5 years for the group as a whole. These data establish the natural history of ATTRwt, provide statistical basis for the design of future interventional clinical trials, and highlight the need for more sensitive diagnostic tests and disease-specific treatments for this disease.

Risk factors for venous thromboembolism in immunoglobulin light chain amyloidosis.

Patients with immunoglobulin light chain amyloidosis are at risk for both thrombotic and bleeding complications. While the hemostatic defects have been extensively studied, less is known about thrombotic complications in this disease. This retrospective study examined the frequency of venous thromboembolism in 929 patients with immunoglobulin light chain amyloidosis presenting to a single referral center, correlated risk of venous thromboembolism with clinical and laboratory factors, and examined complications of anticoagulation in this population. Sixty-five patients (7%) were documented as having at least one venous thromboembolic event. Eighty percent of these patients had events within one year prior to or following diagnosis. Lower serum albumin was associated with increased risk of VTE, with a hazard ratio of 4.30 (CI 1.60-11.55; P=0.0038) for serum albumin less than 3 g/dL compared to serum albumin greater than 4 g/dL. Severe bleeding complications were observed in 5 out of 57 patients with venous thromboembolism undergoing treatment with anticoagulation. Prospective investigation should be undertaken to better risk stratify these patients and to determine the optimal strategies for prophylaxis against and management of venous thromboembolism.

Vertebral compression fractures as the initial presentation of AL amyloidosis: case series and review of literature.

The clinical presentation of AL amyloidosis is highly variable. In this series, we describe five cases of AL amyloidosis with vertebral compression fractures as initial presentation. All five patients had evidence of bone marrow replacement on magnetic resonance imaging and bone marrow biopsies demonstrating diffuse interstitial amyloid deposition. Hepatomegaly and elevated liver enzymes, consistent with liver involvement with amyloidosis, were also seen in each case. All five patients responded well to anti-plasma cell chemotherapy, with normalization of serum free light chain levels, reduction in alkaline phosphatase and improvement in pain and functional status. Although rare, AL amyloidosis should be considered in the differential diagnosis of selected patients with spontaneous vertebral compression fractures. Moreover, there seems to be an association of vertebral compression fractures with liver involvement in AL amyloidosis.

Induction Therapy with Bortezomib Followed by Bortezomib-High Dose Melphalan and Stem Cell Transplantation for Light Chain Amyloidosis: Results of a Prospective Clinical Trial.

The depth of hematologic response has been shown to correlate with survival and organ responses for patients with light chain (AL) amyloidosis. We conducted a prospective trial of 2 cycles of induction with bortezomib and dexamethasone on a twice a week schedule followed by conditioning with bortezomib and high-dose melphalan (HDM) and autologous stem cell transplantation (SCT). The objectives were hematologic responses, tolerability, and survival. Thirty-five patients were enrolled from 2010 to 2013. Of these, 30 proceeded with SCT, whereas 5 did not because of clinical deterioration during induction (n = 3) or complications after stem cell collection (n = 2). Two patients developed features of an autologous graft-versus-host disease-like syndrome post-SCT, which responded to steroids; no other unusual complications were seen. Treatment-related mortality occurred in 8.5% (3/35). Hematologic responses were achieved by 100% of the 27 assessable patients (63% complete response, 37% very good partial response [VGPR]) who completed the planned treatment. By intention-to-treat, hematologic responses occurred in 77% of patients (49% complete response, 29% VGPR). With a median follow-up of 36 months, the median overall survival and progression-free survival were not reached. In conclusion, incorporating bortezomib into induction and conditioning yielded a high rate of hematologic responses after HDM/SCT in patients with AL amyloidosis.

Genetic variation of the transthyretin gene in wild-type transthyretin amyloidosis (ATTRwt).

Wild-type transthyretin amyloidosis (ATTRwt), typically diagnosed as congestive heart failure in elderly Caucasian men, features myocardial amyloid deposits of wild-type plasma protein transthyretin (TTR). ATTRwt is sporadic, its pathogenesis is poorly understood, and currently there are no biomarkers for diagnosis or prognosis. Genetic studies of variant-associated transthyretin amyloidosis have suggested that non-coding TTR gene variants modulate disease. We hypothesized that cis-acting regulatory elements in the TTR gene non-coding regions may modify expression, affecting ATTRwt onset and progression. We studied an ATTRwt cohort consisting of 108 Caucasian males ranging in age from 59 to 87 years with cardiomyopathy due to wild-type TTR deposition; results were compared to 118 anonymous controls matched by age, sex, and race. Four predicted non-coding regulatory regions and all exons in the TTR gene were sequenced using the Sanger method. Eleven common variants were identified; three variants were significantly associated with ATTRwt (p < 0.05), though only one, rs72922940, remained near significance (p corrected = 0.083) after multiple testing correction. Exon analyses demonstrated the occurrence of the p.G26S (G6S) polymorphism in 7 % of ATTRwt subjects and 12 % of controls; this variant was predicted to be a protective factor (p = 0.051). Four variants were significantly associated with age at onset and survival. In this first genetic study of a large, well-characterized cohort of ATTRwt, non-coding and coding variants associated with disease, age at onset, and survival were identified. Further investigation is warranted to determine the prevalence of these variants in ATTRwt, their regulatory function, and potential role in assessing disease risk.

Cooperative stabilization of transthyretin by clusterin and diflunisal.

The circulating protein transthyretin (TTR) can unfold, oligomerize, and form highly structured amyloid fibrils that are deposited in tissues, causing organ damage and disease. This pathogenic process is caused by a heritable TTR point mutation in cases of familial TTR-related amyloidosis or wild-type TTR in cases of age-associated amyloidosis (previously called senile systemic amyloidosis). The TTR amyloid cascade is hypothesized to begin with the dissociation of the TTR native tetrameric structure into folded but unstable monomeric TTR subunits. Unfolding of monomeric TTR initiates an oligomerization process leading to aggregation and fibril formation. Numerous proteostatic mechanisms for regulating the TTR amyloid cascade exist. Extracellular chaperones provide an innate defense against misfolded proteins. Clusterin (CLU), a plasma protein, has the capacity to recognize exposed hydrophobic regions of misfolded proteins, shielding them from aggregation. We have previously demonstrated that CLU is associated with the amyloid fibrils in cardiac tissues from patients with TTR amyloidosis. In this study, we have used tetrameric and monomeric TTR structural variants to determine the ability of CLU to inhibit TTR amyloid fibril formation. Using circular dichroism spectroscopy, we determined that CLU preferentially stabilizes monomeric TTR and generates increasingly stable conformations under acid stress. Moreover, studies using surface plasmon resonance showed a direct interaction of CLU with high-molecular weight TTR oligomers. The interactions of CLU with monomeric and aggregated TTR proceed in a cooperative manner in the presence of diflunisal, a small molecule drug used to stabilize TTR tetramers.

Lysosomal dysfunction and impaired autophagy underlie the pathogenesis of amyloidogenic light chain-mediated cardiotoxicity.

AL amyloidosis is the consequence of clonal production of amyloidogenic immunoglobulin light chain (LC) proteins, often resulting in a rapidly progressive and fatal amyloid cardiomyopathy. Recent work has found that amyloidogenic LC directly initiate a cardio-toxic response underlying the pathogenesis of the cardiomyopathy; however, the mechanisms that contribute to this proteotoxicity remain unknown. Using human amyloidogenic LC isolated from patients with amyloid cardiomyopathy, we reveal that dysregulation of autophagic flux is critical for mediating amyloidogenic LC proteotoxicity. Restoration of autophagic flux by pharmacological intervention using rapamycin protected against amyloidogenic light chain protein-induced pathologies including contractile dysfunction and cell death at the cellular and organ level and also prolonged survival in an in vivo zebrafish model of amyloid cardiotoxicity. Mechanistically, we identify impaired lysosomal function to be the major cause of defective autophagy and amyloidogenic LC-induced proteotoxicity. Collectively, these findings detail the downstream molecular mechanisms underlying AL amyloid cardiomyopathy and highlight potential targeting of autophagy and lysosomal dysfunction in patients with amyloid cardiomyopathy.

Lymphadenopathy as a manifestation of amyloidosis: a case series.

Lymphadenopathy as a manifestation of amyloidosis is rare. Of 3008 new patients with amyloidosis evaluated from 1994 to 2013 at a single center, 47 (1.6%) presented with lymph node enlargement leading to a biopsy and the diagnosis. We conducted a retrospective review of the initial presentation, time to progression, and treatment outcomes for these patients. Upon initial evaluation, 14 (30%) had isolated lymphadenopathy while 33 (70%) had evidence of vital organ involvement. Thirty-nine patients (83%) had systemic AL amyloidosis at initial evaluation or developed it on follow up; there was a single case each of AA, wtTTR and V122ITTR and one untyped amyloidosis. Eleven patients (23%) had IgM monoclonal gammopathy and 3 (6%) had histology consistent with lymphoplasmacytic lymphoma. Of the 14 patients with isolated lymphadenopathy, 10 (71%) eventually progressed to other organ disease requiring treatment at a median time of 10 months (range 4-71). This series demonstrates that patients presenting with amyloid lymphadenopathy usually have AL amyloidosis, and should have a thorough evaluation for other organ involvement at diagnosis. If present, treatment should be similar to that of other patients with systemic AL amyloidosis, but if not, patients should be monitored regularly for development of other organ disease over time.