Solid Organ Transplantation in Amyloidosis

Primary systemic amyloidosis: A brief overview

Primary systemic amyloidosis, or light chain (AL) amyloidosis, is a rare lymphoproliferative disorder in which aberrant light-chain immunoglobulins secreted into the bloodstream aggregate into fibrils and deposit into tissues, causing widespread organ damage and, if not treated, death. This review provides a comprehensive summary of the pathophysiology and manifestations of AL amyloidosis; standard-of-care diagnostic approach; typical treatment regimens; and areas of active investigation.

The Physical Driving Forces of Conformational Transition for TTR91-96 with Proline Mutations

Pathological aggregation of essentially dissociated Transthyretin (TTR) monomer proteins, driven by misfolding and self-interaction, is associated with Transthyretin amyloidosis (ATTR) disease. The TTR monomer proteins consist of several fragments that tend to self-aggregate. Recent experimental studies showed that the sequence of residues TTR91-96 plays an important role in self-aggregation. However, the mechanisms underlying the misfolding and aggregation of the TTR91-96 monomers are still unknown. In this study, we used microsecond molecular dynamics simulations to investigate the misfolding and self-assembly of TTR91-96 Octamers. We also investigated E92P and V94P mutants for comparative analysis. The analysis indicates that hydrophobic interactions and π-π stacking patterns play important roles in reducing the β-sheet content in the V94P and E92P mutants. Additionally, our findings reveal the conformational transition of TTR91-96 octamer from closed β-barrel, open β-barrel to the β-bilayer aggregation. We further elucidate the dynamic mechanism of the transition from intermediate states to stable states. Overall, our research may contribute to the development of drug design to combat fibrous amyloid fibrous diseases.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

An Unusual Diagnosis in a Single-Lung Transplant Recipient: Secondary Amyloidosis

Silicosis, a progressive, fibrotic occupational lung disease with no known treatment, is an uncommon indication for lung transplant. There is a paucity of research on patients with silicosis who have received lung transplants. The long-term consequences of the native lung in patients with severe chronic silicosis who have had a single-lung transplant are also of interest. We present a case of amyloidosis in a patient who underwent a single-lung transplant for silicosis.

Exceptional Liver Transplant Indications: Unveiling the Uncommon Landscape

Liver transplantation represents the definitive intervention for various etiologies of liver failure and encompasses a spectrum of rare indications crucial to understanding the diverse landscape of end-stage liver disease, with significantly improved survival rates over the past three decades. Apart from commonly encountered liver transplant indications such as decompensated cirrhosis and liver cancer, several rare diseases can lead to transplantation. Recognition of these rare indications is essential, providing a lifeline to individuals facing complex liver disorders where conventional treatments fail. Collaborative efforts among healthcare experts lead not only to timely interventions but also to the continuous refinement of transplant protocols. This continued evolution in transplant medicine promises hope for those facing diverse and rare liver diseases, marking a paradigm shift in the landscape of liver disease management.

A Case Report of a Kidney Transplant Recipient With Organizing Pneumonia After Graft Loss

We present a case of a 68-year-old male patient who underwent ABO-incompatible living kidney transplantation from his wife because of immunoglobulin A nephropathy 13 years ago. Over time, the patient showed a gradual decline in graft function and required reinitiation of hemodialysis because of fluid overload, which led to his admission to our hospital. An arteriovenous fistula was created, and subsequently, hemodialysis therapy was started. Because he had chronic cytomegalovirus retinopathy and thrombotic microangiopathy due to immunosuppressive therapy at admission, mycophenolate mofetil and tacrolimus were discontinued during hemodialysis initiation. Only low-dose prednisolone was continued. One week later, the patient had a fever, and chest computed tomography revealed bilateral pneumonia, which was not improved by antibiotics. The patient was diagnosed with organized pneumonia. After ruling out opportunistic infection, including pneumocystis pneumonia, increased doses of prednisolone resulted in the remission of organizing pneumonia.

[Cardiac amyloidosis and aortic valve stenosis]

Aortic valve stenosis in old age has become a topic of interest for cardiology and cardiac surgery after the development of transvascular and transluminal minimally invasive techniques for aortic valve implantation. The observation of amyloid deposits in surgically excised valvular material led to the diagnostics of amyloidosis of the myocardium, which was discovered in up to 20% of the patients who underwent valve implantation. Clinical signs of cardiac amyloidosis, such as carpal tunnel syndrome and ruptured distal biceps tendon should be taken into account. In addition to the electrocardiogram (ECG), echocardiogram and magnetic resonance imaging, ^99mtechnetium bone scintigraphy plays a key diagnostic role. The simultaneous occurrence of severe aortic valve stenosis and amyloidosis explains the special hemodynamic situation of a low gradient with low blood flow in high-grade valve stenosis. The interventional or surgical valve implantation improves the prognosis for these patients, similarly to aortic valve stenosis alone, followed by a specific pharmaceutical treatment depending on the type of amyloidosis.

Solid Organ Transplantation

Please add expansion for AL. Hematologic disease control combined with solid organ transplantation can result in long-term survival in selected patients with light chain (AL) amyloidosis and limited other organ involvement. Restoration of critical cardiac function with organ transplantation can render patients eligible for effective disease-directed therapies, including high-dose therapy and autologous stem cell transplantation. Access to directed-donor organs, exchange programs for renal transplantation, and extended-donor organs for cardiac transplantation improves the availability of organs for patients with AL amyloidosis. Disease recurrence in the graft and progression in other organs remain concerns but often can be managed with a variety of effective plasma cell-directed therapies.