End-stage renal disease in familial amyloidosis ATTR Val30Met: a definitive indication to combined liver-kidney transplantation

Liver transplantation in transthyretin amyloidosis: Characteristics and management related to kidney disease

Orthotopic liver transplantation (LT) was implemented as the inaugural disease-modifying therapy for hereditary transthyretin (ATTR) amyloidosis, a systemic amyloidosis mainly affecting the peripheral nervous system and heart. The first approach to pharmacologic therapy was focused on the stabilization of the TTR tetramer; following that new advent LT was assumed as the second step of treatment, for those patients whose neuropathy becomes worse after a course of pharmacologic therapy. The renal disease has been ignored in hereditary ATTR amyloidosis. The low level of proteinuria or slight renal impairment does not suppose such a heavy glomerular and vascular amyloid deposition. Moreover, severity of renal deposits does not consistently parallel that of myelinated nerve fiber loss. These are pitfalls that limit the success of LT and suggest troublesome criteria for pharmacological therapy or LT. An algorithm of evaluation concerning renal disease and treatment options is presented and some bridges-to-decision are exposed. In stage 4 or 5 kidney disease, the approach remains to deliver combined or sequential liver-kidney transplantation in eligible patients. However, in the majority, hemodialysis is the only option even in the presence of a well-functioning liver graft. In this review, we highlight useful information to aid the transplant hepatologist in the clinical practice.

Pathophysiology and treatment of systemic amyloidosis

Amyloid is an abnormal extracellular fibrillar protein deposit in the tissues. In humans, more than 25 different proteins can adopt a fibrillar conformation in vivo that results in the pathognomonic tinctorial property of amyloid (that is, green birefringence when an affected tissue specimen is stained with Congo red dye and viewed by microscopy under cross-polarized light). Amyloid deposition is associated with disturbance of organ function and causes a wide variety of clinical syndromes that are classified according to the respective fibril protein precursor. Systemic amyloidosis, in which amyloid deposits are widespread and typically accumulate gradually, continues to be fatal and is responsible for about one in 1,500 deaths per year in the UK. Advances in our understanding of the pathogenesis of systemic amyloidosis have resulted in the identification of new therapeutic targets, and several drugs with novel mechanisms of action are currently under development. Meanwhile, an increased awareness of amyloidosis coupled with enhancements to existing diagnostic techniques and therapeutic strategies have already resulted in better outcomes for patients with the disease.

New insights into the clinical evaluation of hereditary transthyretin amyloidosis patients: a single center's experience

Over the last decade, new medical treatment modalities have emerged based on increased insights into amyloid formation. With the increased possibilities for treatment of amyloidosis caused by transthyretin (TTR) amyloid deposits comes the need for diagnostic procedures for early diagnosis and better tools to follow disease progression. This is of particular importance in clinical trials evaluating the efficacy of new treatments. Until recently, the treatment of TTR amyloidosis (ATTR) was based solely on liver transplantation, a procedure that has halted disease progression in many patients. Liver transplantation has been especially effective in patients under the age of 50 years carrying the TTR V30M mutation, whereas the outcome of the procedure has been variable for others, particularly elderly male patients and those carrying a non-V30M mutation. This review concentrates on new insights derived from our center's experience with liver transplantation, how to implement this experience in evaluation of new treatment modalities for ATTR, and how to facilitate early diagnosis of neuropathy with easily available diagnostic tools. Attention has focused on manifestations of the disease that involve the heart and the peripheral nervous system; change in peripheral nerve function has been the primary endpoint in two controlled clinical trials, one finished and one ongoing. New insights into the amyloid formation process and the lessons learned from liver transplantation give the opportunity to design potentially effective treatment modalities for ATTR. It appears reasonable to suspect that a combination of different treatment modalities may be required to treat the disease, and that different treatment regimes will be designed according to the phenotype of the disease. For the patients and their relatives there is now a solid foundation for optimism, with prospects of several effective medical treatment possibilities within the coming decade.

Clinical features of TTR-FAP in Portugal

Familial amyloid polyneuropathy (FAP) is an autosomal dominant disorder characterized by the extracellular deposition of transthyretin (TTR) fibrils in several tissues, particularly in the peripheral nervous system. The largest focus of the disease is in Portugal where the age of disease onset shows a wide range (17-78 years), with 80% of cases developing symptoms before age 40. The characteristic fiber length-dependent sensory-motor and autonomic neuropathy are the neurological hallmark of TTR-FAP. Additional cardiovascular, gastrointestinal (GI), renal and ocular symptoms are the main systemic manifestations that account for phenotypic heterogeneity.

A single center experience of combined liver kidney transplantation

With advancements in the operative techniques, patient survival following liver transplantation (LTx) has increased substantially. This has led to the acceleration of pre-existing kidney disease because of immunosuppressive nephrotoxicity making additional kidney transplantation (KTx) inevitable. On the other hand, in a growing number of patients on the waiting list to receive liver, long waiting time has resulted in adverse effect of decompensated liver on the kidney function. During the last two decades, the transplant community has considered combined liver kidney transplantation (CLKTx) to overcome this problem. The aim of our study is to present an overview of our experience as well as a review of the literature in CLKTx and to discuss the controversy in this regard. All performed CLKTx (n = 22) at our institution as well as all available reported case series focusing on CLKTx are extracted. The references of the manuscripts were cross-checked to implement further articles into the review. The analyzed parameters include demographic data, indication for LTx and KTx, duration on the waiting list, Model for End-Stage Liver Disease (MELD) score, Child-Turcotte-Pugh (CTP) score, immunosuppressive regimen, post-transplant complications, graft and patient survival, and cause of death. From 1988 to 2009, a total of 22 CLKTx were performed at our institution. The median age of the patients at the time of CLKTx was 44.8 (range: 4.5-58.3 yr). The indications for LTx were liver cirrhosis, hyperoxaluria type 1, polycystic liver disease, primary or secondary sclerosing cholangitis, malignant hepatic epithelioid hemangioendothelioma, cystinosis, and congenital biliary fibrosis. The KTx indications were end-stage renal disease of various causes, hyperoxaluria type 1, polycystic kidney disease, and cystinosis. The mean follow-up duration for CLKTx patients were 4.6 +/- 3.5 yr (range: 0.5-12 yr). Overall, the most important encountered complications were sepsis (n = 8), liver failure leading to retransplantation (n = 4), liver rejection (n = 3), and kidney rejection (n = 1). The overall patient survival rate was 80%. Review of the literature showed that from 1984 to 2008, 3536 CLKTx cases were reported. The main indications for CLKTx were oxalosis of both organs, liver cirrhosis and chronic renal failure, polycystic liver and kidney disease, and liver cirrhosis along with hepatorenal syndrome (HRS). The most common encountered complications following CLKTx were infection, bleeding, biliary complications, retransplantation of the liver, acute hepatic artery thrombosis, and retransplantation of the kidney. From the available data regarding the need for post-operative dialysis (n = 673), a total of 175 recipients (26%) required hemodialysis. During the follow-up period, 154 episodes of liver rejection (4.3%) and 113 episodes of kidney rejection (3.2%) occurred. The cumulative 1, 2, 3, and 5 yr survival of both organs were 78.2%, 74.4%, 62.4%, and 60.9%, respectively. Additionally, the cumulative 1, 2, 3, and 5 yr patient survival were 84.9%, 52.8%, 45.4%, and 42.6%, respectively. The total number of reported deaths was 181 of 2808 cases (6.4%), from them the cause of death in 99 (55%) cases was sepsis. It can be concluded that there is still no definitive evidence of better graft and patient survival in CLKTx recipients when compared with LTx alone because of the complexity of the exact definition of irreversible kidney function in LTx candidates. Additionally, CLKTx is better to be performed earlier than isolated LTx and KTx leading to the avoidance of deterioration of clinical status, high rate of graft loss, and mortality. Shorter graft ischemia time and more effective immunosuppressive regimens can reduce the incidence of graft malfunctioning in CLKTx patients. Providing a model to reliably determine the need for CLKTx seems necessary. Such a model can be shaped based upon new and precise markers of renal function, and modification of MELD system.

Liver transplantation in transthyretin-related familial amyloid polyneuropathy

PURPOSE OF REVIEW

Familial amyloid polyneuropathy (FAP) associated with mutations in the gene for transthyretin is a rare, progressively disabling and ultimately fatal inherited disease. Transthyretin is produced predominantly in the liver, and orthotopic liver transplantation (OLT) eliminates more than 95% of variant amyloidogenic transthyretin from the circulation. Liver transplantation remains the only potentially curative treatment in this disorder, but many recent studies have suggested that outcome following transplantation may be poorer than previously considered in some groups of FAP patients.

RECENT FINDINGS

We review here the available data on the use and clinical outcome of OLT in patients with FAP, and consider the significance of particular mutations and cardiac amyloid involvement. The practice of combined organ transplants and domino liver transplantation is also reviewed.

SUMMARY

Published data generally support OLT as a treatment for FAP, particularly in younger patients with the most prevalent transthyretin (TTR) Met30 variant, who have mild symptoms. Although excellent outcomes have been reported, including improvement in autonomic and to a lesser extent peripheral nerve function coupled with regression of visceral amyloid deposits, the results of OLT are influenced by many factors that include properties of particular transthyretin variants, nutritional status, age, severity of neuropathy and cardiac amyloid involvement. Paradoxical acceleration of transthyretin amyloid deposition following OLT may occur in the heart and certain other sites in some patients. The combination of kidney or heart transplantation with OLT may occasionally be appropriate. The long-term outcome of patients with FAP who have undergone OLT, and recipients of FAP domino liver transplants, remain to be determined.