Liver transplantation restores endocrine cells in patients with familial amyloidotic polyneuropathy

Diagnosis and treatment of gastrointestinal dysfunction in hereditary TTR amyloidosis

PURPOSE

To review the management of gastrointestinal symptoms in patients with hereditary transthyretin amyloidosis, discussing diagnostic evaluations, assessment of disease progression and therapeutic strategies that could be implemented in routine practice.

METHODS

Literature review. Key search terms included "gastrointestinal symptoms", "autonomic neuropathy", "hereditary transthyretin amyloidosis" and "familial amyloid polyneuropathy".

RESULTS

Gastrointestinal disturbances are a common and serious manifestation of hereditary transthyretin amyloidosis, with significant effects on patients' quality of life and demonstrating a strong association with mortality. Gastrointestinal involvement is more often subclinical in the early stages of the disease, although in some patients gastric and/or bowel abnormalities may be the inaugural symptoms. In both cases, under-recognition, delayed investigation and suboptimal treatment frequently occur. A clear understanding of the mechanisms underlying gastrointestinal dysfunction in hereditary transthyretin amyloidosis is still lacking, but similar to diabetic enteropathy, multiple pathophysiological alterations seem to play a role.

CONCLUSIONS

Early detection and treatment of gastrointestinal disturbances is key to the successful treatment of this devastating disease. Gastroenterologists play a valuable role in both the diagnosis and the timely management of gastrointestinal symptoms in hereditary transthyretin amyloidosis and should, therefore, be part of a multidisciplinary and comprehensive approach to this disorder.

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.

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.

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.

The role of peptide YY in gastrointestinal diseases and disorders (review)

Peptide YY (PYY) is affected in several gastrointestinal diseases and disorders. Changes in PYY appear to be an adaptive response to alterations in pathophysiological conditions caused by the disease. This applies to gastrointestinal diseases/disorders such as irritable bowel syndrome, inflammatory bowel disease, celiac disease, systemic sclerosis, and post-intestinal resection. By contrast, the changes in PYY in chronic idiopathic slow transit constipation (CST) seem to be of a primary nature, and may be one etiological factor of the disease. Abnormalities in PYY seem to contribute to the development of symptoms present in irritable bowel syndrome, inflammatory bowel disease, gastroenteropathy in long-standing diabetes and CST. The changes in PYY could, however, be favorable in some gastrointestinal disorders such as celiac disease, systemic sclerosis and post-intestinal resection state. Investigating changes in PYY in gastrointestinal diseases/disorders could be beneficial in clinical practice, where a receptor agonist or an antagonist can be used as a drug, depending on the condition. Similar to other neuroendocrine peptides/amines of the gut, PYY has broad physiological/pharmacological effects: it can bind to and activate several receptors with independent actions. Thus, in order to use PYY as a drug, receptor-specific agonists or antagonists need to be developed.

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.

Cardiomyopathy in Swedish patients with the Gly53Glu and His88Arg transthyretin variants

We report two new amyloidogenic transthyretin (TTR) variants detected in the Swedish population. One variant was previously unknown, while the other has been described in a French family. In Swedish patients, both variants have caused late-onset cardiac amyloidosis characterised by heart failure. In both cases, the diagnosis was determined by the detection of amyloid deposits in skin and/or rectal biopsies and identification of TTR mutations by genetic analysis. The index case of the previously unknown mutation (ATTR His88Arg) was a 66-year-old Swedish man, who sought medical attention for increasing dyspnea. Echocardiographic examination disclosed a restrictive cardiomyopathy, and subsequent examinations disclosed TTR amyloidosis. The patient is alive with moderate symptoms one year after the onset of disease. The index case for the new Swedish mutation (ATTR Gly53Glu) is a woman who sought medical attention at the age of 57 because of increasing dyspnea. Echocardiographic examination disclosed a hypertrophic cardiomyopathy with diastolic impairment. The diagnosis of systemic amyloidosis was made by fat aspiration biopsy and histopathology. The patient developed severe intractable heart failure, with pulmonary effusion and ascites. She died four years after the onset of her disease of intractable heart and kidney failure. Post mortem examination of biopsy specimens and blood revealed TTR amyloid deposits and the ATTR Gly53Glu mutation was detected.

Liver Transplantation Does Not Prevent the Development of Life-Threatening Arrhythmia in Familial Amyloidotic Polyneuropathy, Portuguese-Type (ATTR Val30Met) Patients

BACKGROUND

Orthotopic liver transplantation (OLT) is today the only available treatment to halt the progress of familial amyloidotic polyneuropathy (FAP). Because heart arrhythmia and conduction disturbances are well-known manifestations of FAP, the aim of this study was to investigate the occurrence and development of heart conduction and rhythm disturbances in Swedish FAP patients who underwent liver transplantation.

METHODS

Ambulatory 24-hour electrocardiography (ECG) recordings (Holter-ECGs) were available from 30 patients, who had been investigated before and reexamined after OLT. RESULTS.: The number of patients with abnormalities on their ECG recordings increased after OLT. Four patients developed serious arrhythmia after transplantation that necessitated the insertion of a pacemaker 40 months or longer after OLT.

CONCLUSIONS

The development of cardiac conduction disturbances and arrhythmias appear not to be halted by liver transplantation, indicating that the physician should be aware of the potential risk for FAP patients receiving transplants to develop fatal arrhythmia. The follow-up after liver transplantation should include Holter-ECG recordings.

Hereditary transthyretin amyloidosis from a Scandinavian perspective

Hereditary transthyretin (TTR) amyloidosis is a rare often fatal form of systemic amyloidosis, that until recently was considered intractable, with the patients dying from the disease 5-15 years after onset. The phenotype of the disease varies according to the type of mutation, but generally the heart and/or the nervous system is affected. Liver and in some cases heart transplantation has now been shown to stop the progress of the disease, but the outcome depends on the patients' status at the time of operation, as no substantial improvement of the patients' symptoms has been noted after the procedure. Thus an early diagnosis is of importance for the outcome. In the following, we summarize our knowledge of the amyloidogenic TTR mutations found in the Scandinavian countries, their symptoms, how to settle the diagnosis and the outcome of transplantation. Besides, the problems arising from our capability to genetically test asymptomatic members of affected families for the trait will be discussed.

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

Liver transplantation is an accepted treatment of familial amyloidotic polyneuropathy (FAP), Portuguese type (Val30Met), and the outcome so far seems promising. Gastric retention with nausea and vomiting are common complications of the disease, and may interfere with immuno-suppression therapy and prolong recovery after liver transplantation. The aim of this study was to assess the frequency of gastric retention in FAP patients and to evaluate the impact liver transplantation has on gastric emptying. Twenty-two patients, who had undergone liver transplantation, and had been re-examined for gastric retention after the procedure, were included in the study. Gastric emptying was recorded by scintigraphy after the ingestion of a 99m-technetium (99mTc)-labelled meal (omelette). The half-time (T50) of the emptying phase was calculated. Gastrointestinal symptoms before and after transplantation were recorded, and the majority of patients were also subjected to an upper endoscopic examination, where the presence of solid residual in the stomach was regarded as consistent with gastric retention. A high frequency of gastric retention was noted among the patients both before and after transplantation, and no significant improvement for the group was noted, even though decreased gastric emptying was noted for patients with a duration of the disease for less that 4 years. Patients who improved their nutritional status after transplantation had a faster gastric emptying than those who deteriorated. From our findings it can be concluded that gastric retention is a common complication of FAP and that gastric emptying in patients with longstanding disease (> or = 4 years) is unchanged after liver transplantation.

Progression of cardiomyopathy after liver transplantation in patients with familial amyloidotic polyneuropathy, Portuguese type

BACKGROUND

Transthyretin amyloidosis is today an accepted indication for orthotopic liver transplantation (OLT). For several mutations progression of the cardiomyopathy has been observed after OLT. The aim of this study was to assess the course of cardiac involvement in Swedish familial amyloidotic polyneuropathy (FAP), Portuguese type, after OLT. By comparison of the echocardiographic findings before OLT with those obtained after, the course of the heart involvement was followed.

METHODS

Twenty-three patients, who had undergone OLT and were examined with echocardiography 1-12 months before OLT, were available for the study. Twenty-one patients were examined 12-27 months after OLT, and 12 were re-examined 52-71 months after OLT. Two-dimensional and M-mode echocardiography were performed in accordance with the standards of the American Society of Echocardiography.

RESULTS

A significantly increased septal and left ventricular posterior wall thickness and a significantly increased left atrial dimension was observed at the post-OLT examinations, indicating a progression of the amyloid heart disease. This increase of the cardiac involvement was neither correlated to waiting time for OLT or to pre-operative signs of cardiomyopathy.

CONCLUSIONS

Even though the production of the amyloidogenic-mutated transthyretin is stopped by OLT, the cardiomyopathy may progress after the operation even for the Portuguese type of FAP. The increase of the septal and left ventricular posterior wall thickness after OLT is not restricted to patients with signs of left ventricular hypertrophy before the transplantation. The findings have important implications for the follow-up of FAP patients after OLT.