Project description:Light chain (AL) amyloidosis is caused by a usually small plasma-cell clone that is able to produce the amyloidogenic light chains. They are able to misfold and aggregate, deposit in tissues in the form of amyloid fibrils and lead to irreversible organ dysfunction and eventually death if treatment is late or ineffective. Cardiac damage is the most important prognostic determinant. The risk of dialysis is predicted by the severity of renal involvement, defined by the baseline proteinuria and glomerular filtration rate, and by the response to therapy. The specific treatment is chemotherapy targeting the underlying plasma-cell clone. It needs to be risk-adapted, according to the severity of cardiac and/or multi-organ involvement. Autologous stem cell transplant (preceded by induction and/or followed by consolidation with bortezomib-based regimens) can be considered for low-risk patients (~20%). Bortezomib combined with alkylators is used in the majority of intermediate-risk patients, and with possible dose escalation in high-risk subjects. Novel, powerful anti-plasma cell agents were investigated in the relapsed/refractory setting, and are being moved to upfront therapy in clinical trials. In addition, the use of novel approaches based on antibodies targeting the amyloid deposits or small molecules interfering with the amyloidogenic process gave promising results in preliminary studies. Some of them are under evaluation in controlled trials. These molecules will probably add powerful complements to standard chemotherapy. The understanding of the specific molecular mechanisms of cardiac damage and the characteristics of the amyloidogenic clone are unveiling novel potential treatment approaches, moving towards a cure for this dreadful disease.
Project description:Light chain (AL) amyloidosis is the most common form of amyloidosis involving the kidney. It is characterized by albuminuria, progressing to overt nephrotic syndrome and eventually end-stage renal failure if diagnosed late or ineffectively treated, and in most cases by concomitant heart involvement. Cardiac amyloidosis is the main determinant of survival, whereas the risk of dialysis is predicted by baseline proteinuria and glomerular filtration rate, and by response to therapy. The backbone of treatment is chemotherapy targeting the underlying plasma cell clone, that needs to be risk-adapted due to the frailty of patients with AL amyloidosis who have cardiac and/or multiorgan involvement. Low-risk patients (?20%) can be considered for autologous stem cell transplantation that can be preceded by induction and/or followed by consolidation with bortezomib-based regimens. Bortezomib combined with alkylators, such as melphalan, preferred in patients harboring t(11;14), or cyclophosphamide, is used in most intermediate-risk patients, and with cautious dose escalation in high-risk subjects. Novel, powerful anti-plasma cell agents, such as pomalidomide, ixazomib, and daratumumab, prove effective in the relapsed/refractory setting, and are being moved to upfront therapy in clinical trials. Novel approaches based on small molecules interfering with the amyloidogenic process and on antibodies targeting the amyloid deposits gave promising results in preliminary uncontrolled studies, are being tested in controlled trials, and will likely prove powerful complements to chemotherapy. Finally, improvements in the understanding of the molecular mechanisms of organ damage are unveiling novel potential treatment targets, moving toward a cure for this dreadful disease.
Project description:Amyloid light chain (AL) amyloidosis is a systemic disease characterised by the aggregation of misfolded immunoglobulin light chain (LC), predominantly in the heart and kidneys, causing organ failure. If untreated, the median survival of patients with cardiac AL amyloidosis is 6 months from the onset of heart failure. Protracted time to establish a diagnosis, often lasting >1 year, is a frequent factor in poor treatment outcomes. Cardiologists, to whom patients are often referred, frequently miss the opportunity to diagnose cardiac AL amyloidosis. Nearly all typical cardiac support measures, with the exception of diuretics, are ineffective and may even worsen clinical symptoms, emphasising the need for accurate diagnosis. Patients with severe cardiac involvement face poor outcomes; heart transplantation is rarely an option because of multiorgan involvement, rapid clinical decline and challenges in predicting which patients will respond to treatment of the underlying plasma cell disorder. Early diagnosis and prompt treatment with ââ'¬Ëœsource therapiesââ'¬â"¢ that limit the production of amyloidogenic LC are associated with better survival and improvement in organ function after a median of 2.4 months following haematological complete response. However, organ recovery is often incomplete because these source therapies do not directly target deposited amyloid. Emerging amyloid-directed therapies may attenuate, and potentially reverse, organ dysfunction by clearing existing amyloid and inhibiting fibril formation of circulating aggregates. Improved recognition of AL amyloidosis by cardiologists allows for earlier treatment and improved outcomes.
Project description:BackgroundAmyloid light-chain (AL) amyloidosis is an ultra-rare disease associated with significant morbidity and mortality. Few studies have examined the global epidemiology of this condition.MethodsThis study estimated the diagnosed incidence and 1-year, 5-year, 10-year, and 20-year period prevalence of AL amyloidosis in 2018 for countries in and near Europe, and in the United States (US), Canada, Brazil, Japan, South Korea, Taiwan, and Russia. A systematic literature review (SLR) was conducted to identify country-specific, age- and gender-specific diagnosed incidence of AL amyloidosis and observed survival data-point inputs for an incidence-to-prevalence model. Extrapolations were used to estimate incidence and prevalence for countries without registry or published epidemiological data.ResultsOf 171 publications identified in the SLR, 10 records met the criteria for data extraction, and two records were included in the final incidence-to-prevalence model. In 2018, an estimated 74,000 AL amyloidosis cases worldwide were diagnosed during the preceding 20 years. The estimated incidence and 20-year prevalence rates were 10 and 51 cases per million population, respectively.ConclusionsOrphan medicinal product designation criteria of the European Medicines Agency or Electronic Code of Federal Regulations indicate that a disease must not affect > 5 in 10,000 people across the European Union or affect < 200,000 people in the US. This study provides up-to-date epidemiological patterns of AL amyloidosis, which is vital for understanding the burden of the disease, increasing awareness, and to further research and treatment options.
Project description:IntroductionInformation detailing the experience of patients with light chain (AL) amyloidosis is lacking. The primary aim of this study was to gather data on the patient experience to understand the challenges in diagnosis and to gain insight into barriers to accessing appropriate care.MethodsPatients with amyloidosis, family members, and caregivers were invited to participate in an online 16-question survey (available from January 29 to February 5, 2015). Participants with AL amyloidosis were sent an eight-question follow-up survey.ResultsThe initial survey was completed by 533 participants (follow-up survey completed by 201 participants). AL amyloidosis was the most common diagnosis. For 37.1% of respondents, the diagnosis of amyloidosis was not established until ≥ 1 year after the onset of initial symptoms. Diagnosis was received after visits to 1, 2, 3, 4, or ≥ 5 physicians by 7.6%, 23.5%, 20.3%, 16.8%, and 31.8% of respondents, respectively. Correct diagnosis was most often made by hematologists/oncologists (34.1%). Treatments included chemotherapy (63.1%) and stem cell transplantation (38.9%) and were difficult to tolerate for 54.1% of respondents. A significant number of respondents felt uninformed about clinical trials. Nevertheless, approximately half (46.1%) believed that enrolling in a trial would enhance their care.ConclusionsEstablishing a diagnosis of amyloidosis is difficult. Current treatments are difficult to tolerate and do not substantially improve quality of life for most patients. There is an urgent need for well-tolerated therapies with clear treatment benefit. Patient awareness of clinical trials can be improved, especially given that respondents indicated high willingness to participate.
Project description:Amyloid formation and deposition of immunoglobulin light-chain proteins in systemic amyloidosis (AL) cause major organ failures. While the ? light-chain is dominant (?/?=1:2) in healthy individuals, ? is highly overrepresented (?/?=3:1) in AL patients. The structural basis of the amyloid formation and the sequence preference are unknown. We examined the correlation between sequence and structural stability of dimeric variable domains of immunoglobulin light chains using molecular dynamics simulations of 24 representative dimer interfaces, followed by energy evaluation of conformational ensembles for 20 AL patients' light chain sequences. We identified a stable interface with displaced N-terminal residues, provides the structural basis for AL protein fibrils formation. Proline isomerization may cause the N-terminus to adopt amyloid-prone conformations. We found that ? light-chains prefer misfolded dimer conformation, while ? chain structures are stabilized by a natively folded dimer. Our study may facilitate structure-based small molecule and antibody design to inhibit AL. This article is part of a Special Issue entitled: Accelerating Precision Medicine through Genetic and Genomic Big Data Analysis edited by Yudong Cai & Tao Huang.
Project description:BACKGROUND:Light chain (AL) amyloidosis is a rare, complex disease associated with significant morbidity and mortality. Delays in diagnosis are common and may have detrimental consequences on patients' prognosis. Too little is known regarding the patient journey to diagnosis. OBJECTIVE:The objective of this study was to describe the patient-reported journey to a correct diagnosis for AL amyloidosis. METHODS:Using a mixed-methods approach, data were collected from clinician (n = 4) and patient (n = 10) interviews and a survey of community-based patients with AL amyloidosis (n = 341). Data were used to document the patient experience between the onset of symptoms and the receipt of a diagnosis. RESULTS:Delays in diagnosis were common. Qualitative and quantitative data indicated that initial symptoms were varied and similar to other more prevalent diseases. Two themes regarding the journey to diagnosis emerged: (1) barriers to an early diagnosis; and (2) the emotional toll of the journey. Time to diagnosis was heavily influenced by how patients interpreted their initial symptoms, whether they sought early medical help, and challenges associated with making differential diagnoses. Survey results indicate that patients with primary cardiac involvement were more likely to receive a delayed diagnosis than those with primary kidney involvement. Patients described mixed emotions associated with the eventual diagnosis of AL amyloidosis. CONCLUSIONS:These data support a need for better early identification and support for patients seeking a diagnosis. Increasing clinician awareness may reduce the time to diagnosis. Additional research is needed to identify optimal diagnostic testing to reduce delays in treatment initiation and subsequent severe impacts on health.
Project description:Amyloid myopathy associated with a plasma cell dyscrasia is a rare cause of muscle hypertrophy. It can be a challenging diagnosis, since pathological findings are often elusive. In addition, the mechanism by which immunoglobulin light-chain deposition stimulates muscle overgrowth remains poorly understood. We present a 53-year old female with a 10-year history of progressive generalized muscle overgrowth. Congo-red staining and immunohistochemistry revealed perivascular lambda light chain amyloid deposits, apparent only in a second muscle biopsy. The numbers of central nuclei and satellite cells were increased, suggesting enhanced muscle progenitor cell formation. Despite the chronicity of the light chain disease, the patient showed complete resolution of hematologic findings and significant improvement of her muscle symptoms following autologous bone marrow transplantation. This case highlights the importance of early diagnosis and therapy for this treatable cause of a chronic myopathy with muscle hypertrophy.
Project description:Systemic light chain amyloidosis (AL) is one of several protein misfolding diseases and is characterized by extracellular deposition of immunoglobulin light chains in the form of amyloid fibrils [1]. Immunoglobulin (Ig) proteins consist of two light chains (LCs) and two heavy chains (HCs) that ordinarily form a heterotetramer which is secreted by a plasma cell. In AL, however, a monoclonal plasma cell population produces an abundance of a pathogenic LC protein. In this case, not all of the LCs pair with the HCs, and free LCs are secreted into circulation. The LC-HC dimer is very stable, and losing this interaction may result in an unstable LC protein [2]. Additionally, somatic mutations are thought to cause amyloidogenic proteins to be less stable compared to non-amyloidogenic proteins [3-5], leading to protein misfolding and amyloid fibril formation. The amyloid fibrils cause tissue damage and cell death, leading to patient death within 12-18 months if left untreated [6]. Current therapies are harsh and not curative, including chemotherapy and autologous stem cell transplants. Studies of protein pathogenesis and fibril formation mechanisms may lead to better therapies with an improved outlook for patient survival. Much has been done to determine the molecular factors that make a particular LC protein amyloidogenic and to elucidate the mechanism of amyloid fibril formation. Anthony Fink's work, particularly with discerning the role of intermediates in the fibril formation pathway, has made a remarkable impact in the field of amyloidosis research. This review provides a general overview of the current state of AL research and also attempts to capture the most recent ideas and knowledge generated from the Fink laboratory.