Molecular Imaging of Primary Amyloid Cardiomyopathy
Molecular Imaging of Primary Amyloid Cardiomyopathy
Cardiac amyloidosis is a major cause of early treatment-related death and poor overall
 survival in individuals with systemic light chain amyloidosis. This project will develop a
 novel approach to visualize cardiac amyloid deposits using advanced imaging methods. The
 long-term goal of this work is to identify the mechanisms of cardiac dysfunction, in order to
 guide the development of novel life-saving treatments.
Primary light chain amyloidosis (AL) is the most common systemic amyloidosis, resulting from
 a plasma cell dyscrasia, a hematological malignancy. It causes a restrictive cardiomyopathy
 (AL-CMP) in over 70% of individuals. AL-CMP is as lethal as stage 4 lung cancer and more
 lethal than any other form of restrictive heart disease; if untreated, the mortality rate is
 50% within 18 months. Moreover, myocardial dysfunction, the hallmark of AL-CMP, significantly
 increases early treatment related mortality, predominantly cardiovascular death, and is a
 powerful predictor of poor long-term survival. Two potentially treatable mechanisms underlie
 myocardial dysfunction-mechanical effects of amyloid and toxic effects from circulating light
 chain/ amyloid interactions-and predispose to heart failure, arrhythmias, and sudden death in
 individuals with AL-CMP. Until now, efforts to determine the mechanisms of AL-CMP have been
 hampered by a lack of animal models and the limitations of noninvasive techniques to directly
 image myocardial amyloid. A recent breakthrough, 18F-florbetapir PET/CT, has provided for the
 first time specific and quantitative imaging of myocardial amyloid including toxic amyloid
 protofibrils. Furthermore, we propose to investigate three pre-clinically proven pathways of
 light chain toxicity in humans-myocardial oxidative metabolism, oxidative stress, and
 coronary microvascular function. Our central hypotheses are that myocardial 18F-florbetapir
 retention is a biomarker for aggressiveness of AL-CMP and that effective chemotherapy will,
 by reducing circulating light chains, decrease aggressiveness of AL-CMP and improve oxidative
 stress, myocardial oxidative metabolism, microvascular function and contractile function,
 prior to an improvement in myocardial amyloid content. In Aim 1, we will quantify myocardial
 18F-florbetapir retention as a marker of aggressive myocardial disease in individuals with
 AL-CMP and active plasma cell dyscrasia compared to control individuals with AL-CMP and
 long-term hematological remission. In Aim 2, we propose, using advanced imaging, to assess
 the effects of light chain reduction due to chemotherapy on myocardial structure, function,
 and metabolism and define the time course of these changes. Serial ECV and strain imaging by
 CMR, serum F2-isoprostanes and peroxynitrite levels, myocardial oxidative metabolism (Kmono)
 and coronary flow reserve by 11C-acetate PET, and 18F-florbetapir imaging will not only
 intricately characterize the myocardial substrate in AL-CMP, but also identify changes in
 response to therapy. The proposed studies offer the potential to transform our current
 understanding of AL-CMP as a restrictive heart disease caused by passive amyloid-related
 architectural damage to that of a more complex disorder resulting from both passive and
 aggressive factors. The results of these studies may form the foundation for drug discovery
 programs to prevent and cure AL-CMP.

 Interactions of environmental factors, immunity, and host-related factors likely trigger
 AL-amyloidosis, but have not yet been explored. Changes in metal ions and gut microbiota may
 be causal, representing the integrated effects of all these factors, or may be the downstream
 effect of systemic amyloid deposition in the organ systems. A plethora of recent literature
 strongly support the role of microbiota in the pathogenesis of several diseases, suggesting
 that gut microbiota changes with age, influences heart failure (HF) outcomes, and plays a
 role in the formation of β-amyloid deposits in Alzheimer's disease. Importantly, alterations
 in lifestyle, diet, prebiotics, probiotics, or phenols and gut microbiota may represent
 therapeutic and preventative strategies in amyloid disease, but it has not been explored in
 AL-amyloidosis. We propose to study the role of salivary and gut microbiome in AL
 amyloidosis.
Inclusion criteria:

 -  Age > 18 years

 -  Diagnosis of light chain amyloidosis by standard criteria (immunofixation of serum and
 urine, IgG free light chain (FLC) assay, a biopsy of fat pad/ bone marrow, or organ
 biopsy, followed by typing of the light chain using immunohistochemistry or immunogold
 assay with confirmation by Mass spectroscopy as needed)

 -  For subjects traveling from out of town referred for systemic AL therapy based on
 clinical evaluation and laboratory testing, but, pending biopsy results, study
 enrollment and procedures may begin before official confirmation of biopsy
 results. If biopsy is negative for AL amyloidosis, subject will be considered a
 screen failure. There will be no more than 10 subjects who fall under this screen
 failure for the duration of the study.

 -  Subjects with localized amyloid deposition and non-systemic AL disease will be
 eligible for enrollment in group D.

 -  Willing and able to provide consent

 -  Additional inclusion criteria for the Remission AL-CMP: Hematological response defined
 as complete hematological remission or very good partial response-differential free
 light chain (dFLC)<40 mg/dL for > 1 year prior to enrollment

 -  Additional inclusion criteria for the Active AL-CMP - exercise: Ability to perform
 supine bicycle exercise. Enrollment to this arm will stop after 36 subjects complete
 baseline and 6 months studies.

 -  Additional inclusion criteria for the Active AL Pre-CMP - Normal left ventricular wall
 thickness (≤ 12 mm) and normal LVEF (≥55%) on echocardiography within 3 months or
 increased wall thickness with normal cardiac biomarker levels: not meeting above
 definition.

 -  Additional inclusion criteria for Control Multiple Myeloma subjects: diagnosis of
 multiple myeloma without concomitant amyloidosis by standard criteria

 -  Additional inclusion criteria for Control Heart Failure subjects: diagnosis of heart
 failure without amyloidosis by standard criteria

 -  Additional inclusion criteria for the active AL-CMP: Abnormal TnT 5th generation
 levels (>9 ng/L: Female, >14 ng/L: Male) or abnormal age appropriate N terminal
 pro-brain natriuretic peptide, NT-proBNP (abnormal values: <50 years: >450 pg/ml;
 50-75 years:>900 pg/ml; >75 years: >1800 pg/ml)

 Exclusion Criteria:

 -  Hemodynamic instability

 -  Decompensated heart failure (unable to lie flat for 1 hour)

 -  Concomitant non-ischemic non-amyloid heart disease (valvular heart disease or dilated
 cardiomyopathy)

 -  Known obstructive epicardial coronary artery disease with stenosis > 50% in any single
 territory

 -  Severe claustrophobia despite use of sedatives

 -  Presence of MRI contraindications such as metallic implants (pacemaker or ICD) at the
 time of study enrollment except for Control Heart Failure subjects. Control HF
 subjects with no devices, or, with strictly MR compatible devices will be eligible to
 undergo MRI.

 -  Significant renal dysfunction with estimated glomerular filtration rate < 30 ml/min/m2
 within 14 days of each cardiac MRI study. Subjects who develop renal dysfunction over
 the course of the study, meeting criteria listed above, will be excluded from the
 cardiac MRI scan except for control HF subjects. These subjects with eGFR < 30
 ml/min/1.73 m2 will undergo MRI without gadolinium contrast.

 -  Subjects on dialysis will be excluded

 -  Pregnant state. For women in child bearing age, a urine pregnancy test will be
 performed prior to the PET and the cardiac MRI studies

 -  Documented allergy to F-18 florbetapir, C-11 acetate or gadolinium.

 -  Additional exclusion criteria for the active AL-CMP subjects: Subjects unable to
 return to BWH for 6 and 12 month clinical evaluation

 -  Additional exclusion criteria for active AL-CMP-exercise subjects: Inability to
 exercise or return to BWH for C-11 acetate PET/CT at baseline and 6 month clinical
 evaluations.

 -  Additional exclusion criteria for active AL Pre-CMP- Inability to return to BWH 12
 month clinical evaluation.

 Additional exclusion criteria for microbiota study: Documented hypertrophic cardiomyopathy,
 HIV or chronic viral hepatitis, documented inflammatory bowel disease, systemic
 antibiotics, antivirals, antifungals or antiparasitic agents within 6 months, unable to
 mail the stool sample in a timely manner, bowel surgery, colon cancer, received
 chemotherapy, and pregnancy.