Gastric emptying before and after liver transplantation for familial amyloidotic polyneuropathy, Portuguese type (Val30Met)

Abnormal small bowel motility in patients with hereditary transthyretin amyloidosis

BACKGROUND

Gastrointestinal complications are common in hereditary transthyretin amyloid (ATTRm) amyloidosis. The underlying mechanisms have not been fully elucidated, and the patients' small bowel function remains largely unexplored. The aim of the present study was to compare the small bowel motility in ATTRm amyloidosis patients with that in non-amyloidosis patient controls.

METHODS

ATTRm amyloidosis patients undergoing evaluation for liver transplantation were consecutively investigated with 24-hour duodenojejunal manometry (n = 19). The somatostatin analogue octreotide was used to induce fasting motility. Patients with age at onset of ≥50 years were defined as late-onset cases. For each patient, three age- and sex-matched patient controls (n = 57) were selected from the total pool of investigated patients.

KEY RESULTS

Manometry was judged as abnormal in 58% of the patients and in 26% of the patient controls (P = .01). Patients displayed significantly more daytime phase III migrating motor complexes than patient controls (median 4 vs 2, P < .01), and had a higher frequency of low-amplitude complexes (16% vs 4%; however, this difference did not reach statistical significance, P = .10). Furthermore, late-onset patients showed a delay in octreotide response (5.4 vs 3.8 minutes, P < .01), but this was not observed for early-onset patients or within the control group.

CONCLUSIONS AND INFERENCES

Patients with ATTRm amyloidosis displayed abnormalities in their small bowel motility more frequently than non-amyloidosis patient controls, and the manometric pattern was probably best consistent with a combined neuromyopathic disorder. The delayed octreotide response in late-onset patients warrants further investigation.

Amyloid deposition in a mouse model humanized at the transthyretin and retinol-binding protein 4 loci

Familial amyloidotic polyneuropathy is an autosomal dominant disorder caused by a point mutation in the transthyretin (TTR) gene. The process of TTR amyloidogenesis begins with rate-limiting dissociation of the TTR tetramer. Thus, the TTR stabilizers, such as Tafamidis and Diflunisal, are now in clinical trials. Mouse models will be useful to testing the efficacy of these drugs. Although several mouse models have been generated, they all express mouse Rbp4. Thus, human TTR associates with mouse RBP4, resulting in different kinetic and thermodynamic stability profiles of TTR tetramers. To overcome this problem, we previously produced humanized mouse strains at both the TTR and Rbp4 loci (Ttr ^hTTRVal30 , Ttr ^hTTRMet30 , and Rbp4 ^hRBP4 ). By mating these mice, we produced double-humanized mouse strains, Ttr ^{hTTRVal30/hTTRVal30} :Rbp4 ^hRBP4/hRBP4 and Ttr ^{hTTRVal30/Met30} :Rbp4 ^hRBP4/hRBP4 . We used conventional transgenic mouse strains on a wild-type (Ttr ^+/+ :Tg[6.0hTTRMet30]) or knockout Ttr background (Ttr^-/-:Tg[6.0hTTRMet30]) as reference strains. The double-humanized mouse showed 1/25 of serum hTTR and 1/40 of serum hRBP4 levels. However, amyloid deposition was more pronounced in Ttr ^{hTTRVal30/Met30} :Rbp4 ^hRBP4/hRBP4 than in conventional transgenic mouse strains. In addition, a similar amount of amyloid deposition was also observed in Ttr ^{hTTRVal30/ hTTRVal30} :Rbp4 ^{hRBP4/ hRBP4} mice that carried the wild-type human TTR gene. Furthermore, amyloid deposition was first observed in the sciatic nerve without any additional genetic change. In all strains, anti-TTR antibody-positive deposits were found in earlier age and at higher percentage than amyloid fibril deposition. In double-humanized mice, gel filtration analysis of serum revealed that most hTTR was free of hRBP4, suggesting importance of free TTR for amyloid deposition.

Management of gastrointestinal complications in hereditary transthyretin amyloidosis: a single-center experience over 40 years

Hereditary transthyretin amyloidosis (ATTRm amyloidosis) is a rare disease caused by the deposition and accumulation of insoluble non-native transthyretin fibrils in the body. The disease inevitably results in widespread organ disruption, and poor life expectancy. The GI tract is one organ system vulnerable to disruption and, although the clinical presentation of the disease varies, GI involvement affects most patients with ATTRm amyloidosis. Areas covered: This article presents our experience with diagnosing and treating the GI symptoms of ATTRm amyloidosis patients at our center over the last 40 years, in the Swedish clustering area of the disease. Our aim is to help other physicians to better manage GI complications in patients with this rare but widespread condition. Expert commentary: GI symptoms are debilitating complications for ATTRm amyloidosis patients to experience, yet with the appropriate questioning and diagnosis methods, symptomatic treatments of these symptoms can be implemented to provide relief. Further, patients with fewer GI complications and a good nutritional status are also better candidates for liver transplantation which, in selected cases, is the best disease-modifying treatment of ATTRm amyloidosis to date.

Orthotopic liver transplantation changes the course of gastric antral vascular ectasia: a case series from a transplant center

BACKGROUND AND AIM

Gastric antral vascular ectasia (GAVE) is an important cause of upper gastrointestinal bleeding and anemia in patients with cirrhosis. The aim of our study was to evaluate the effect of orthotopic liver transplantation (OLT) on GAVE and associated anemia.

PATIENTS AND METHODS

We performed a chart review and identified all cirrhotic patients with GAVE who underwent OLT at the University Of Alabama at Birmingham between 2005 and 2013. Population's demographics, etiology of cirrhosis, comorbidities, presentation and treatment modalities of GAVE, endoscopic and histopathologic reports, hemoglobin values before and after transplant, and immunosuppressive regimens were collected.

RESULTS

Twelve patients were identified, mean age 52.4±4.4 years; seven were men (58.3%); 11 (91.7%) were White; and 6 of 12 patients had biopsy-proven GAVE. The most common etiology of cirrhosis in the cohort was chronic hepatitis C and obesity was the most common chronic condition in 50 and 83.3%, respectively. Anemia resolution was observed in 9/12 (75%) patients who underwent OLT with an increase in hemoglobin from 8.1±2.4 (5.7-13.1) before transplant to 12.0±1.4 (10-15) after transplant (P<0.0001). Esophagogastroduodenoscopy after transplant was performed in all 12 (100%) patients. The mean time between transplant and post-OLT esophagogastroduodenoscopy was 13.8±18.28 (2-57) months; complete resolution of GAVE was observed in 10 (83.3%) patients, with resolving GAVE in one (8.3%) patient.

CONCLUSION

GAVE is an important cause of anemia and upper gastrointestinal bleeding in patients with liver cirrhosis. Our findings show that liver transplantation can resolve GAVE and related anemia.

CSP-1103 (CHF5074) stabilizes human transthyretin in healthy human subjects

Hereditary amyloid polyneuropathy is a type of protein misfolding disease. Transthyretin (TTR) is a homotetrameric serum protein and TTR tetramer dissociation is the limiting step in amyloid fibril formation. Thus, prevention of TTR dissociation is a promising therapeutic approach and some TTR stabilizers have been approved for the treatment of TTR amyloidosis. CSP-1103 (CHF5074) is a non-steroidal anti-inflammatory derivative that lacks cyclooxygenase inhibitory activity. In vitro, CSP-1103 stabilizes the TTR tetramer by binding to the thyroxine (T4) binding site. We have previously shown that serum TTR levels were increased by oral CSP-1103 administration through stabilization of TTR tetramers in humanized mice at both the Ttr locus and the Rbp4 locus. To determine whether CSP-1103 stabilizes TTR tetramers in humans, multiple CSP-1103 oral doses were administered for two weeks to 48 healthy human volunteers in a double-blind, placebo-controlled, parallel-group study. CSP-1103 treatment stabilized TTR tetramers in a dose-dependent manner under normal or denaturing stress conditions, thereby increasing serum TTR levels. Preincubation of serum with CSP-1103 or diflunisal in vitro increased the TTR tetramer stability. Computer simulation analysis revealed that the binding affinities of CSP-1103 with TTR at pH 7.0 were similar to those of tafamidis, thus confirming that CSP-1103 has potent TTR-stabilizing activity.

Amyloidosis of the gastrointestinal tract and the liver: clinical context, diagnosis and management

Amyloidosis is a group of disorders that can manifest in virtually any organ system in the body and is thought to be secondary to misfolding of extracellular proteins with subsequent deposition in tissues. The precursor protein that is produced in excess defines the specific amyloid type. This requires histopathological confirmation using Congo red dye with its characteristic demonstration of green birefringence under cross-polarized light. Gastrointestinal (GI) manifestations are common and the degree of organ involvement dictates the symptoms that a patient will experience. The small intestine usually has the most amyloid deposition within the GI tract. Patients generally have nonspecific findings such as abdominal pain, nausea, diarrhea, and dysphagia that can often delay the proper diagnosis. Liver involvement is seen in a majority of patients, although symptoms typically are not appreciated unless there is significant hepatic amyloid deposition. Pancreatic involvement is usually from local amyloid deposition that can lead to type 2 diabetes mellitus. In addition, patients may undergo either endoscopic or radiological evaluation; however, these findings are usually nonspecific. Management of GI amyloidosis primarily aims to treat the underlying amyloid type with supportive measures to alleviate specific GI symptoms. Liver transplant is found to have positive outcomes, especially in patients with specific variants of hereditary amyloidosis.

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.

Outcome of gastric emptying and gastrointestinal symptoms after liver transplantation for hereditary transthyretin amyloidosis

Background

Hereditary transthyretin amyloid (ATTR) amyloidosis is a rare but fatal autosomal dominant condition that is present all over the world. A liver transplantation has been shown to halt the progress of the disease in selected patients and is currently considered to be the standard treatment. Gastrointestinal manifestations are common in hereditary ATTR amyloidosis and are important for the patients’ morbidity and mortality. The aim of this study was to evaluate the long-term outcome of gastric emptying, gastrointestinal symptoms and nutritional status after liver transplantation for the disease.

Methods

Swedish patients with hereditary ATTR amyloidosis transplanted between 1990 and 2012 were included. A standardized method for measuring gastric emptying with a Tc^99m-labelled meal followed by scintigraphy was utilized. Validated questionnaires were used to assess gastrointestinal symptoms and the modified body mass index (mBMI), in which BMI is multiplied by s-albumin, was used to evaluate nutritional status. Non-parametrical statistical tests were used.

Results

Gastric emptying rates and nutritional statuses were evaluated approximately eight months before and two and five years after liver transplantation, whereas gastrointestinal symptoms were assessed in median nine months before and two and nine years after transplantation. No significant change was found in gastric emptying (median half-time 137 vs. 132 vs. 125 min, p = 0.52) or nutritional status (median mBMI 975 vs. 991 vs. 973, p = 0.75) after transplantation. Gastrointestinal symptom scores, however, had increased significantly over time (median score 7 vs. 10 vs. 13, p < 0.01).

Conclusions

Gastric emptying and nutritional status were maintained after liver transplantation for hereditary ATTR amyloidosis, although gastrointestinal symptom scores had increased over time.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-015-0284-4) contains supplementary material, which is available to authorized users.

Post hoc analysis of nutritional status in patients with transthyretin familial amyloid polyneuropathy: impact of tafamidis

INTRODUCTION

Gastrointestinal symptoms are common among patients with transthyretin familial amyloid polyneuropathy (TTR-FAP). This post hoc analysis evaluated the nutritional status of TTR-FAP patients treated with tafamidis while enrolled in clinical trials.

METHODS

Nutritional status was measured by the modified body mass index (mBMI = BMI × albumin level). Treatment-related changes in mBMI were reported for 71 Val30Met TTR-FAP patients who completed an 18-month, randomized, double-blind, placebo-controlled trial and who continued into its open-label, 12-month extension.

RESULTS

At month 18, mBMI worsened in the placebo group (n = 33) (-33 ± 16 kg/m(2) g/l, P = 0.04 versus baseline) but improved in the tafamidis group (n = 38) (+37 ± 14 kg/m(2) g/l, P = 0.01 versus baseline) such that the effect size between the groups was statistically significant (P = 0.001). By month 30 (completion of the open-label extension), placebo patients with 12 months of tafamidis treatment and tafamidis-treated patients with 30 months of treatment both tended to increase their mBMI (28 ± 19 kg/m(2) g/l and 16 ± 18 kg/m(2) g/l, respectively). Increase in BMI was most pronounced in patients with low BMI at entry into the studies.

CONCLUSIONS

mBMI is well suited to monitor disease progression in TTR-FAP patients. The delay in neurological deterioration brought about by tafamidis treatment in clinical trials is associated with improvements in, or maintenance of, mBMI.

FUNDING

This study was sponsored by Pfizer Inc., New York, USA.

Recent advances in transthyretin amyloidosis therapy

Mutant (MT) forms of transthyretin (TTR) cause the most common type of autosomal-dominant hereditary systemic amyloidosis-familial amyloidotic polyneuropathy (FAP). Until 20 years ago, FAP was thought to be an endemic disease, but FAP is known to occur worldwide. To date, more than 130 mutations in the TTR gene have been reported. Genotype-phenotype correlations are seen in FAP, and some variation in clinical presentation is often observed in individual kindreds with the same mutation and even among family members. Of the pathogenic TTR mutations, Val30Met was the first to be identified and is the most frequent known mutation found throughout the world. Studies of patients with FAP amyloidogenic TTR (ATTR) Val30Met documented sensorimotor polyneuropathy, autonomic dysfunction, heart and kidney failure, gastrointestinal tract (GI) disorders, and other symptoms leading to death, usually within 10 years of the onset of disease. Diagnosis is sometimes delayed, especially in patients without a clear family history and typical clinical manifestations, since diagnosis requires various studies and techniques such as histopathology, genetic testing, and mass spectrometry. For treatment of FAP, liver transplantation (LT) reportedly halts the progression of clinical manifestations. Exchange of an FAP patient's diseased liver with a healthy liver causes MT TTR in the body to be replaced by wild-type (WT) TTR. Although clinical evaluations indicated that progression of other clinical symptoms such as peripheral neuropathy, GI symptoms, and renal involvement usually halted after LT in FAP ATTR Val30Met patients, recent studies suggested that LT failed to prevent progression of cardiac amyloidosis in FAP ATTR Val30Met patients after LT, with this failure reportedly being due to continued formation of amyloid that derived mainly from WT TTR secreted from the transplanted non-mutant liver graft. In recent years, many therapeutic strategies have been proposed, and several ongoing therapeutic trials involve, for example, stabilizers of TTR tetramers (tafamidis and diflunisal) and gene therapies to suppress TTR expression (antisense methods and use of small interfering RNAs). These novel therapies may prove to prevent progression of FAP.

THAOS: gastrointestinal manifestations of transthyretin amyloidosis - common complications of a rare disease

Background

Transthyretin amyloidosis is a systemic disorder caused by amyloid deposits formed by misfolded transthyretin monomers. Two main forms exist: hereditary and wild-type transthyretin amyloidosis, the former associated with transthyretin gene mutations. There are several disease manifestations; however, gastrointestinal complications are common in the hereditary form. The aim of this study was to explore the prevalence and distribution of gastrointestinal manifestations in transthyretin amyloidosis and to evaluate their impact on the patients’ nutritional status and health-related quality of life (HRQoL).

Methods

The Transthyretin Amyloidosis Outcomes Survey (THAOS) is the first global, multicenter, longitudinal, observational survey that collects data on patients with transthyretin amyloidosis and the registry is sponsored by Pfizer Inc. This study presents baseline data from patients enrolled in THAOS as of June 2013. The modified body mass index (mBMI), in which BMI is multiplied with serum albumin, was used to assess the nutritional status and the EQ-5D Index was used to assess HRQoL.

Results

Data from 1579 patients with hereditary transthyretin amyloidosis and 160 patients with wild-type transthyretin amyloidosis were analyzed. Sixty-three percent of those with the hereditary form and 15% of those with the wild-type form reported gastrointestinal symptoms at enrollment. Unintentional weight loss and early satiety were the most frequent symptoms, reported by 32% and 26% of those with transthyretin gene mutations, respectively. Early-onset patients (<50 years) reported gastrointestinal complaints more frequently than those with a late onset (p < 0.001) and gastrointestinal symptoms were more common in patients with the V30M mutation than in those with other mutations (p < 0.001). For patients with predominantly cardiac complications, the prevalence of gastrointestinal manifestations was not evidently higher than that expected in the general population. Both upper and lower gastrointestinal symptoms were significant negative predictors of mBMI and the EQ-5D Index Score (p < 0.001 for all).

Conclusions

Gastrointestinal symptoms were common in patients with hereditary transthyretin amyloidosis and had a significant negative impact on their nutritional status and HRQoL. However, patients with wild-type transthyretin amyloidosis or transthyretin mutations associated with predominantly cardiac complications did not show an increased prevalence of gastrointestinal disturbances.

Loss of gastric interstitial cells of Cajal in patients with hereditary transthyretin amyloidosis

BACKGROUND

Hereditary transthyretin (TTR) amyloidosis is a systemic neuropathic disorder caused by TTR gene mutations. Gastrointestinal complications are common and the underlying mechanisms remain unclear. The interstitial cells of Cajal (ICC) function as pacemaker cells in the gastrointestinal tract and are important for gastrointestinal motility. The aim of this study was to investigate the densities of gastric ICC and nerves in patients with TTR amyloidosis compared to non-amyloidosis controls.

METHODS

Antral wall autopsy specimens from 11 Japanese ATTR V30M patients and 10 controls were analyzed with immunohistochemistry and computerized analysis. Antibodies to c-Kit and TMEM16A were used to assess ICC and an antibody to PGP 9.5 was used to assess nervous tissue. The study was approved by a Japanese ethical committee.

RESULTS

The densities of c-Kit-immunoreactive (IR) ICC were significantly lower in the circular and longitudinal muscle layers of patients compared to controls (p = 0.004 for both). Equivalent results were found for TMEM16A-IR ICC. There were no significant differences in PGP 9.5-IR cells in the circular or longitudinal muscle layers between patients and controls (p = 0.173 and 0.099, respectively).

CONCLUSIONS

A loss of gastrointestinal ICC may be an important factor for the digestive disturbances in hereditary TTR amyloidosis.

Gastric emptying in hereditary transthyretin amyloidosis: the impact of autonomic neuropathy

BACKGROUND

Gastrointestinal (GI) complications are common in hereditary transthyretin amyloidosis and an autonomic dysfunction has been considered to explain these symptoms. The aim of this study was to investigate the impact of autonomic neuropathy on gastric emptying in hereditary transthyretin amyloidosis and to relate these findings to nutritional status, GI symptoms, gender, and age at disease onset.

METHODS

Gastric emptying was evaluated with gastric emptying scintigraphy. Spectral analysis of the heart rate variability and cardiovascular responses after tilt test were used to assess the autonomic function. The nutritional status was evaluated with the modified body mass index (s-albumine × BMI).

KEY RESULTS

Gastric retention was found in about one-third of the patients. A weak correlation was found between the scintigraphic gastric emptying rate and both the sympathetic (rs = -0.397, P < 0.001) and parasympathetic function (rs = -0.282, P = 0.002). The gastric emptying rate was slower in those with lower or both upper and lower GI symptoms compared with those without symptoms (median T(50) 123 vs 113 min, P = 0.042 and 192 vs 113 min, P = 0.003, respectively). Multiple logistic regression analysis showed that age of onset (OR 0.10, CI 0.02-0.52) and sympathetic dysfunction (OR 0.23, CI 0.10-0.51), but not gender (OR 0.76, CI 0.31-1.84) and parasympathetic dysfunction (OR 1.81, CI 0.72-4.56), contributed to gastric retention.

CONCLUSIONS AND INFERENCES

Gastric retention is common in hereditary transthyretin amyloidosis early after onset. Autonomic neuropathy only weakly correlates with gastric retention and therefore additional factors must be involved.

Amyloidosis of the gastrointestinal tract: a 13-year, single-center, referral experience

Amyloidosis of the gastrointestinal tract, with biopsy-proven disease, is rare. We reviewed a series of patients who presented with biopsy-proven gastrointestinal amyloidosis and report their clinical characteristics, treatments, and survival. This is a retrospective review of data prospectively collected from January 1998 to December 2011 in a tertiary referral center; 2,334 patients with all types of amyloidosis were evaluated during this period. Seventy-six patients (3.2%) had biopsy-proven amyloid involvement of the gastrointestinal tract. Their median age was 61 years (range, 34-79). Systemic amyloidosis with dominant gastrointestinal involvement was present in 60 (79%) patients, whereas the other 16 (21%) patients had amyloidosis localized to the gastrointestinal tract without evidence of an associated plasma cell dyscrasia or other organ involvement. Of the 60 systemic cases, 50 (83%) had immunoglobulin light-chain, five (8%) had familial lysozyme, three (5%) had wild-type transthyretin, and two (3%) had mutant transthyretin amyloidosis. The most frequent symptoms for all patients were weight loss in 33 (45%) and gastrointestinal bleeding in 27 (36%). Incidental identification of amyloidosis on routine endoscopic surveillance played a role in the diagnosis of seven patients with systemic immunoglobulin light-chain, and four patients with immunoglobulin light-chain localized to the gastrointestinal tract. Amyloid protein subtyping was performed in 12 of the cases of localized disease, and all had lambda light chain disease. Of the 50 patients with systemic immunoglobulin light-chain amyloidosis, 45 were treated with anti-plasma cell therapy. The median survival has not been reached for this group. For the 16 patients with localized gastrointestinal amyloidosis, supportive care was the mainstay of treatment; none received anti-plasma cell therapy. All 16 are alive at a median follow-up of 36 months (range, 1-143). Patients with biopsy-proven gastrointestinal amyloidosis often present with weight loss and bleeding. In localized cases, all that underwent typing were due to lambda light chain amyloidosis and none progressed to systemic disease during the period of follow-up. Most patients with systemic disease had immunoglobulin light-chain, and their tolerance of therapy and median survival were excellent. Although a rare manifestation of amyloidosis, staining for amyloid should be considered in patients undergoing gastrointestinal biopsy who have unexplained chronic gastrointestinal symptoms.

Arrhythmia--a pitfall in tests of cardiac autonomic function after liver transplantation for familial amyloidotic polyneuropathy: a long-term follow-up of Swedish patients

Liver transplantation (LT) is a potentially curative treatment for hereditary transthyretin amyloidosis, of which familial amyloid polyneuropathy (FAP) is the most common form in Sweden. This study investigated the long-term development in heart rate variability (HRV) after LT in Swedish FAP patients. HRV was analyzed before LT, and during a first (<40 months) and a second (>40 months) follow-up recording after transplantation, respectively. Power spectrum analysis was performed on 2-min sequences in the supine position and after passive tilt, after careful identification of patients with arrhythmia. Data were obtained from 33 patients, but 18 patients had developed cardiac arrhythmia or were pacemaker-treated (4 before LT and 14 after LT) and three patients had not performed the first follow-up recording. In the remaining 12 patients, HRV decreased between the pretransplant evaluation and the first follow-up, thereafter no significant changes were found. In conclusion, our study showed that the progressive development of cardiac arrhythmias after LT is a major pitfall when assessing cardiac autonomic function in FAP patients, especially in patients older than 40 years. In the minority of patients with sinus rhythm in all recordings, cardiac autonomic modulation remained stable after transplantation and no improvement was noted.

Amyloid and the GI tract

Amyloidosis is characterized by the extracellular deposition of an abnormal fibrillar protein, which disrupts tissue structure and function. Amyloid may be localized to a single organ, such as the GI tract, or be systemic where the amyloid type is defined by the respective fibril precursor protein. Among patients with systemic amyloidosis, histological involvement of the gastrointestinal (GI) tract is very common but often subclinical. The presence and pattern of GI symptoms varies substantially, not only between the different amyloid types but also within them. GI presentations are frequently nonspecific and include macroglossia, dyspepsia, hemorrhage, a change in bowel habit and malabsorption. Endoscopic and radiological features of amyloidosis are also nonspecific, with the small intestine most commonly affected. In the absence of specific treatments for GI amyloidosis, therapy is aimed at reducing or eliminating the supply of the respective fibril precursor protein. Supportive measures such as nutritional support and antidiarrheal agents should be instigated while awaiting the clinical improvement associated with a successful reduction in the abundance of the fibril precursor protein. GI tract surgery should be performed only if the benefits clearly outweigh the risks, as there is a risk of decompensation of organs affected by amyloid.

Systemic amyloidosis and the gastrointestinal tract

Systemic amyloidosis is characterized by the extracellular deposition of protein in an abnormal fibrillar form. Several different types of amyloidosis exist, each defined by the identity of their respective fibril precursor protein. Among patients with systemic amyloidosis, histological involvement of the gastrointestinal tract is very common but is often subclinical. Conversely, primary diseases of the gastrointestinal tract can cause systemic amyloidosis; for example, AA amyloidosis can occur secondary to IBD. The presence and pattern of gastrointestinal symptoms varies substantially, not only between the different types of amyloidosis but also within them. Typical clinical presentations, most of which are nonspecific, include macroglossia, hemorrhage, motility disorders, disturbance of bowel habit and malabsorption. Endoscopic and radiological features are also nonspecific, with the small intestine most commonly affected. Currently, the aim of therapy for amyloidosis is to slow amyloid formation by reducing the abundance of the fibril precursor protein. No specific treatments for the gastrointestinal symptoms of systemic amyloidosis are available; however, case reports and small published series encourage nutritional support for patients with motility disorders and pharmacological agents for treatment of diarrhea. Surgical procedures should be contemplated only in an emergency setting because of the risk of decompensation of organs affected by amyloid deposition.

Outcome of heart rate variability and ventricular late potentials after liver transplantation for familial amyloidotic polyneuropathy

Reduced heart rate variability (HRV) is common in familial amyloidotic polyneuropathy (FAP), as well as cardiac arrhythmias. We examined the effects of liver transplantation (LTx) on 24-h HRV and ventricular late potentials. Twenty-one liver-transplanted FAP patients underwent Holter-ECG recordings and signal average electrocardiography recordings (SAECG) before and after LTx. Mean follow-up time after LTx was 21.7 months. Three patients had marked increased HRV after LTx, but this was in all cases caused by the development of subtle atrial arrhythmia and did not reflect an improvement in the cardiac autonomic control. In total, ten patients were excluded from analysis of HRV because of arrhythmia. Spectral analysis of HRV showed no significant differences before and after LTx in the remaining 11 patients. Positive late potentials were found in 33% of patients before LTx and this proportion was unchanged after LTx. Reduced HRV and positive late potentials are common in Swedish FAP patients, and remain stable, at least within the short term after transplantation. If an increase of HRV after transplantation is observed, it should raise the suspicion that the patient has developed subtle atrial arrhythmia.

Ten-year follow-up of peripheral nerve function in patients with familial amyloid polyneuropathy after liver transplantation

BACKGROUND

The electrophysiological long-term effects of liver transplantation on peripheral nerve function in patients with familial amyloid polyneuropathy (FAP) have not been evaluated.

METHODS

Eight FAP patients with a proven ATTRVal30Met gene were observed for 10 years after liver transplantation. We performed repeated measurement of maximal motor nerve conduction velocity (MCV), distal latency, size of compound muscle action potential (CMAP) and maximal sensory nerve conduction velocity (SCV) in both the ulnar and tibial nerves. We also recorded the coefficients of variance in the R-R interval on the electrocardiogram (CV(R-R)).

RESULTS

Some autonomic symptoms subsided but motor and sensory symptoms 10 years after transplantation were either slightly improved or almost the same as before surgery in 7 of 8 patients. These 7 have returned to their previous social lives including their jobs. The MCV of the tibial nerve slightly improved, and other parameters of motor and sensory nerve function and CV(R-R) did not show any deterioration during the 10-year observation period.

CONCLUSIONS

Liver transplantation can halt the progression of peripheral neuropathy in FAP patients.

Impact of liver transplantation on cardiac autonomic denervation in familial amyloid polyneuropathy

Familial amyloid polyneuropathy (FAP) is a rare and severe hereditary form of amyloidosis, due to the deposition of a genetic variant transthyretin essentially produced by the liver, and characterized by both sensorimotor and autonomic neuropathy. Liver transplantation (LT) is the most effective treatment to stop the progression of the disease. Cardiac amyloid infiltration is usually associated with cardiac denervation, restrictive cardiomyopathy, conduction disturbances, and sometimes sudden death. Whether the cardiac involvement related to amyloid deposition may be altered after LT remains unclear. We conducted the present study to define the outcome of cardiac involvement after LT in 31 patients with FAP (age, 39 +/- 12 yr). Patients were evaluated before and after LT (24 +/- 15 mo). Cardiac sympathetic denervation was assessed by both iodine-123 metaiodobenzylguanidine (MIBG) scintigraphy and heart rate variability (HRV) analysis. The scintigraphic importance of sympathetic denervation was evaluated globally on planar imaging using heart-to-mediastinum activity ratio (H/M) measured 4 hours after injection, and regionally using single-photon emission tomography (SPET) imaging. Amyloid myocardial infiltration was assessed by echocardiography. Diffuse sympathetic denervation was found when using cardiac MIBG planar imaging in patients evaluated before LT and compared with 12 control subjects (H/M: 1.45 +/- 0.29 vs. 1.98 +/- 0.35, p < 0.001). On SPET images, defects were diffuse in 12 patients and focal in 19 patients, with predominance at the inferior and apical segments. No change in sympathetic innervation was found in patients after LT as assessed either with planar imaging (H/M after LT: 1.46 +/- 0.28, p = not significant vs. H/M before LT) or with SPET imaging. HRV nonspectral indexes showed that the standard deviation of all cycles was significantly lower in patients compared with control subjects, and remained unchanged after LT. Conduction disturbances and ventricular arrhythmias were associated with low cardiac MIBG uptake, and progressed after LT. The left ventricular wall was slightly thickened in patients, and a further increase was observed after LT (posterior wall from 9.2 +/- 1.8 to 10.1 +/- 2.3 mm, p = 0.02; septal wall from 10.6 +/- 2.7 to 12.1 +/- 4, p = 0.046). Neurologic status stabilized in 26 patients, but worsened in the 5 patients who had the most severe cardiac sympathetic denervation before LT as measured by MIBG imaging. The magnitude of the cardiac sympathetic denervation remained stable 2 years after LT in patients with FAP, whereas the cardiac amyloid infiltration progressed. The importance of cardiac sympathetic denervation found in FAP patients before LT was associated with a neurologic worsening after LT.

Mechanism of constipation in familial amyloid polyneuropathy: a case report

Previously no functional study has been available for the mechanism of constipation in familial amyloid polyneuropathy (FAP). We performed a gut function test in a 78-year-old woman with transthyretin-type FAP who had severe constipation. The gut function test showed a prolonged colonic transit time, a low anal pressure at rest and upon squeezing, loss of the spontaneous phasic rectal contractions, and weak abdominal strain. All these abnormalities suggested a peripheral autonomic dysfunction, corresponding to the enteric neuropathy that was confirmed upon autopsy.

Indications for Liver Transplantation in Patients with Amyloidosis: A Single-Center Experience with 11 Cases

Familial amyloidotic polyneuropathy (FAP) is an inherited disorder with the systemic deposition of amyloid fibrils containing mutant transthyretin variants. The mutant form of transthyretin amyloidosis is produced mainly in the liver. Successful liver transplantation (LTx) could eliminate the source of the variant transthyretin molecule, and is now the only known curative treatment. The aim of this study is to evaluate the results of LTx for FAP at the University of Heidelberg. Eleven patients who underwent LTx between 1985 and 2004 with the diagnosis of FAP were evaluated. Of 11 patients, seven (64%) were male and four (36%) were female. The mean age was 49.5 years (range 27-70). Met 30 (n=5) was the most common type of amyloidosis followed by Arg 50 (n=3), Val 107 (n=2), and Phe 33 (n=1). All of the patients were selected for LTx and Domino LTx was performed in six patients. The majority (80%) of the patients with type Met 30 amyloidosis are alive, whereas in other types of amyloidosis only 33% are living. This finding emphasizes better prognosis of Met 30 variant of FAP in comparison to other variants such as Arg 50, Val 107, and Phe 33. After LTx, improvement of clinical symptoms (completely or partially) was observed in six patients (55%). In conclusion, LTx is considered as the only therapeutic alternative in patients with amyloidosis accompanied by hepatic synthesis of the amyloid protein. The most important risk factors for LTx can be predicted by assessing the nutritional condition of the patient, the duration of the disease, and the amyloid variant. Therefore, precise diagnostic measures are required before listing a patient for LTx. Domino LTx is an acceptable form of LTx that can preserve the pool of organ donors. In order to stop the progression of FAP, LTx would be justified in a subgroup of patients with amyloidosis. Based on our results, we support the idea that the effectiveness of extended preoperative period before LTx or the transplantation of other transthyretin variants other than Met 30 is questionable.

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.