Transthyretin amyloid deposits in lumbar spinal stenosis and assessment of signs of systemic amyloidosis.

BACKGROUND: Wild-type transthyretin (ATTRwt) amyloidosis is the most common systemic amyloidosis in Western countries and manifests mainly as progressive restrictive cardiomyopathy. OBJECTIVE: To study the prevalence of ATTR deposits in ligament tissue in patients undergoing surgery for lumbar spinal stenosis and to assess whether these deposits are associated with cardiac amyloidosis. MATERIALS AND METHODS: A total of 250 patients, aged 50-89 (57% women), none with known cardiovascular disease, were included. Ligaments were investigated microscopically for amyloid. ATTR type was determined by immunohistochemistry and fibril type by Western blot. The amount of amyloid was graded 0-4. All patients with grade 3-4 ATTR deposits were offered cardiac investigation including ECG, cardiac ultrasound, plasma NT-proBNP and cardiac magnetic resonance (CMR), including modern tissue characterization. RESULTS: Amyloid was identified in 221 of the samples (88.4%). ATTR appeared in 93 samples (37%) of whom 42 (17 women and 25 men) were graded 3-4; all had fibril type A (mixture of full-length TTR and fragmented TTR). Twenty-nine of 42 patients with grade 3-4 ATTR deposits accepted cardiovascular investigations; none of them had definite signs of cardiac amyloidosis, but five men had a history of carpal tunnel syndrome. CONCLUSIONS: The prevalence of ATTR deposits in ligamentum flavum in patients with lumbar spinal stenosis was high but not associated with manifest ATTR cardiac amyloidosis. However, the findings of fibril type A, the prevalence of previous carpal tunnel syndrome and ATTR amyloid in surrounding adipose and vascular tissue indicate that amyloid deposits in ligamentum flavum may be an early manifestation of systemic ATTR disease.

One mutation, two distinct disease variants: unravelling the impact of transthyretin amyloid fibril composition.

Although hereditary transthyretin (h-ATTR) amyloidosis is a monogenetic disease, a large variation in its phenotype has been observed. The common hypothesis of amyloid fibril formation involves dissociation of the transthyretin (TTR) tetramer into monomers that after misfolding reassemble into amyloid fibrils. This notion is partly challenged by the finding of two distinct types of amyloid fibrils. One of these, type A, consists of C-terminal ATTR fragments and full-length TTR, whereas the other, type B, consists only of full-length TTR. All organs of an individual patient contain ATTR deposits of either type A or type B fibrils, and the composition in each individual remains unchanged over time. The finding of two distinct types of ATTR fibrils suggests that there are at least two different pathways in operation for ATTR fibril formation. For the most common European mutation, TTR Val30Met, ATTR fibril composition is related to the outcome of liver transplantation, which is the first successful treatment for the disease, and the penetrance of the trait. In addition, the presence of C-terminal ATTR fragments has an impact on the affinity for various tracers used for noninvasive imaging of amyloid depositions such as 99 m-technetium-diphosphono-propanodicarboxylic acid scintigraphy and positron emission tomography utilizing Pittsburgh component B, and even for the gold standard diagnostic procedure, tissue biopsy stained by Congo red and examined under polarized light. The importance of amyloid fibril composition needs to be taken into consideration when designing clinical trials of treatment modalities, and also in the evaluation of diagnostic methods such as imaging techniques.

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.

Mitochondrial haplogroup is associated with the phenotype of familial amyloidosis with polyneuropathy in Swedish and French patients.

Familial amyloidotic polyneuropathy (FAP) is a monogenic disease caused by mutations in the transthyretin (TTR) gene. The phenotype of the most common TTR mutation, V30M, varies within and between populations. Oxidative stress and protein misfolding are cellular processes involved in the development of FAP. Because the mitochondria are important for both these processes, we investigated if mitochondrial haplogroups are related to age at onset of the disease in Swedish and French FAP patients. Mitochondrial haplogroup analysis was performed on 25 early-onset (below 40 years) and 29 late-onset (above 51 years) Swedish FAP patients. DNA from 249 Swedish individuals served as controls. In addition, 6 early-onset and 17 late-onset French FAP patients were examined with 25 French controls. The haplogroup distribution among late-onset Swedish and French cases was similar to that found in the general populations, whereas among early-onset cases a different haplogroup distribution was seen. The relatively rare haplogroup K was significantly more common among early-onset cases. Our findings substantiate the suggestion that a genetic component, still to be found, affecting mitochondrial function has an impact on the amyloid generating process in transthyretin amyloidosis.

Do troponin and B-natriuretic peptide detect cardiomyopathy in transthyretin amyloidosis?

OBJECTIVES: Cardiomyopathy is a well known complication in familial amyloidotic polyneuropathy (FAP). Troponin T and B-natriuretic peptide (BNP) have been shown to be excellent markers for heart complications in AL-amyloidosis. The aim of the study was to investigate troponin T, troponin I and BNP as markers for myocardial damage and failure in FAP. DESIGN: Retrospective investigation of patients with FAP. SETTING: Tertiary referral centre. SUBJECTS: Twenty-nine patients who had been submitted for evaluation of FAP. INTERVENTIONS: Two-dimensional M-mode and Doppler echocardiography and strain echocardiographic examination. Measurement of Troponin T, troponin I and BNP. RESULTS: Troponin T was detectable in only three patients who all had abnormal interventricular septal (IVS) thickness. Troponin I was abnormal in six patients (21%), of which only two had an increased IVS thickness. The heart function was generally well preserved in the patients in spite of hypertrophy of the IVS in 14 patients. BNP was elevated in 22 patients (76%), and it correlated significantly with IVS thickness and basal septal strain. CONCLUSIONS: Transthyretin amyloid seems to be less harmful to myocytes than that of AL amyloid as evaluated by serum troponin T and I as well as by echocardiography. BNP appears to be a sensitive marker for cardiomyopathy in FAP, and could prove valuable for follow-up purposes as has been shown for AL-amyloidosis patients.

Liver transplantation for familial amyloidotic polyneuropathy (FAP): a single-center experience over 16 years.

Orthotopic liver transplantation (LTx) is currently the only available treatment that has been proven to halt the progress of familial amyloidotic polyneuropathy (FAP). The aim of this study was to assess mortality and symptomatic response to LTx for FAP. All 86 FAP patients transplanted at our hospital between April 1990 and November 2005 were included in the study. Five patients underwent retransplantation. The 1-, 3- and 5-year patient survival rates in patients transplanted during 1996-2005 were 94.6%, 92.3% and 92.3%, respectively, a significant difference from the rates of 76.7%, 66.7% and 66.7%, respectively, during 1990-1995 (p = 0.0003). Multivariate analysis revealed that the age at the time of LTx (>or=40 years), duration of the disease (>or=7 years) and modified body mass index (mBMI) (<600) were independent prognostic factors for patient survival. A halt in the progress of symptoms was noted in most patients, but only a minority experienced an improvement after LTx. To optimize the posttransplant prognosis, LTx should be performed in the early stages of the disease, and close post-LTx monitoring of heart function by echocardiography and of heart arrhythmia by Holter ECG is mandatory.

Advanced glycation end product is implicated in amyloid-related kidney complications.

BACKGROUND: Kidney failure is a common complication in familial amyloidotic polyneuropathy (FAP). It has been suggested that advanced glycation end products (AGEs) play an important role in the development and pathogenesis of FAP. MATERIAL AND METHODS: To evaluate the impact of AGEs on FAP patients' kidney dysfunction, we measured AGE in serum and urine of 28 FAP patients and 18 healthy controls by AGE-specific enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry utilizing antibodies to AGE and the receptor for AGE (RAGE) were used on kidney tissue from 3 FAP patients and 3 diabetic patients to disclose a correlation between amyloid deposits and AGE-RAGE. RESULTS: The glomeruli of FAP patients were heavily deposited with amyloid and the glomerular size was enlarged. The space between Bowman's capsule and glomerulus was totally covered by the enlarged glomerulus. AGE and RAGE were deposited in glomeruli and tubuli and correlated with amyloid deposits. Decreased AGE levels in the liver-transplanted FAP patients' serum compared with that of non-transplanted patients were noted, and AGE concentration in serum tended to be higher in non-transplanted FAP patients compared with normal control subjects. There were no differences in the AGE urine levels in FAP patients compared with controls. No correlation could be found between AGE in urine and serum compared with serum albumin, serum creatinine and creatinine clearance. CONCLUSIONS: The accumulation of AGE, RAGE and amyloid in the kidney of FAP patients suggests that these molecules play an important role in the origin and pathogenesis of renal failure in FAP patients.

Amyloid heart disease mimicking hypertrophic cardiomyopathy.

OBJECTIVE: To investigate the importance of transthyretin (TTR) gene mutations in explaining the phenotypic expression in patients diagnosed with hypertrophic cardiomyopathy (HCM) in northern Sweden. BACKGROUND: Hypertrophic cardiomyopathy is relatively common and often caused by mutations in sarcomeric protein genes. Mutations in the TTR gene are also common, one of which causes familial amyloid polyneuropathy (FAP), with peripheral polyneuropathy and frequently, cardiac hypertrophy. These circumstances were highlighted by the finding of an index case with amyloidosis, presenting itself as HCM. Initial rectal and fat biopsies did not show amyloid deposits. Later on, the patient was shown to carry a TTR gene mutation, and cardiac amyloidosis was confirmed by myocardial biopsy. Only then was a repeated fat biopsy positive for amyloid deposits. DESIGN: Cross-sectional study. SETTING: Cardiology tertiary referral centre. SUBJECTS: Forty-six unrelated individuals with HCM and the index case were included. Common diagnostic criteria for HCM were used. The 46 patients with HCM were previously analysed for mutations in eight sarcomeric protein genes and the TTR gene was now analysed by denaturing high-performance liquid chromatography and direct sequencing. RESULTS: One mutation in the TTR gene (Val30Met) was found in three individuals and the index case. CONCLUSIONS: Three of the 46 cases with HCM carried the Val30Met mutation, and were considered likely to have cardiac amyloidosis, like the index case. As a correct diagnosis of cardiac amyloidosis is mandatory for a potentially life-saving treatment, TTR mutation analysis should be considered in cases of HCM not explained by mutations in sarcomeric protein genes.

Impact of homozygosity for an amyloidogenic transthyretin mutation on phenotype and long term outcome.

Although amyloidogenic transthyretin (ATTR) mutations are common in several populations, such as black Americans, the small number of diagnosed patients homozygous for TTR amyloid and the short follow up in most studies has until now prevented an analysis of their phenotype. In Sweden, nine homozygous patients from eight families carrying the ATTR mutation Val30Met, which gives rise to fatal neuropathic amyloidosis (FAP), have been identified and have now been followed for up to 15 years. This has enabled an analysis of the phenotype of homozygous patients. Genetic testing and detection of amyloid deposits in the vitreous body or in intestinal or skin biopsies confirmed the diagnosis in all patients. The patients' symptoms were obtained from medical records. For comparison, we used a group of 35 heterozygous non-transplanted patients with FAP (18 men and 17 women), who had been evaluated at the Department of Medicine, Umeå University Hospital before their deaths. Vitreous amyloidosis was the most prevalent symptom in the homozygous group, and in two patients it was the only manifestation of the disease during their lifetime. The age at onset was not different from that of heterozygous patients, and their survival tended not to be shorter but actually longer than for heterozygotes. Homozygosity for the mutation associated with FAP, ATTR Val30Met, does not implicate a more severe phenotype for Swedish patients. The most common symptom was vitreous opacity, which may be the only manifestation of the disease. These findings point to the possibilities of different pathways for amyloid formation, or the presence of hitherto unknown genes operating in amyloid formation.

Discordant penetrance of the trait for familial amyloidotic polyneuropathy in two pairs of monozygotic twins.

BACKGROUND: Familial amyloidotic polyneuropathy (FAP) is caused by mutated transthyretin in which valine at position 30 is substituted by methionine (ATTR Val30Met). FAP is inherited as an autosomal dominant trait with variable penetrance. CASES: Two pairs of DNA confirmed monozygotic twin brothers, 63 and 37 years of age respectively, who are heterozygous for the ATTR Val30Met gene, have been identified in Sweden. In the first twin pair (A), the onset of typical FAP symptoms occurred at the age of 48 for twin A1, whilst his twin brother (A2) is still free from FAP symptoms 13 years later. In the second pair of twins (B), the onset of polyneuropathy occurred at the age of 34 for the proband (B1), whilst his brother (B2) is healthy 3 years after the onset of his brother's disease. DISCUSSION: In the following, a detailed description of the clinical presentation of the Swedish twin pairs is provided together with a discussion of possible environmental factors initiating the onset of the disease.

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.

Effect of budesonide enema on remission and relapse rate in distal ulcerative colitis and proctitis.

BACKGROUND: Glucocorticosteroid enemas are equally effective as 5-ASA enemas in the treatment of active distal ulcerative colitis (UC). With the introduction of budesonide, the risk of systemic side effects may be reduced. We investigated whether budesonide enema, 2 mg/100 ml, administered twice daily (b.i.d.) could increase the remission rate in comparison with the once daily (o.d.) standard regimen. Furthermore, we evaluated whether 2 mg budesonide enema, given twice weekly, could have a relapse preventing effect. METHODS: 149 patients with active distal UC were treated in a controlled, double-blind multicentre study with two parallel groups: placebo enema in the morning and budesonide enema in the evening (i.e. 2 mg/day) or budesonide enema b.i.d. (i.e. 4 mg/day) until remission (absence of clinical symptoms and endoscopic healing) or at most 8 weeks. Patients in remission were randomized to either budesonide enema or placebo enema twice weekly for 24 weeks or until relapse. RESULTS: The remission rates at 4 weeks were 33% for o.d. and 41% for b.i.d. regimens (NS) and correspondingly 51% and 54% at 8 weeks (NS). The b.i.d. group had an increased frequency of impaired adrenal function, 32% versus 4.8% (P = 0.001). The relapse rates during maintenance treatment with budesonide enema and placebo were 15% versus 24% after 8 weeks, 31% versus 27% after 16 weeks and 41% versus 51% after 24 weeks (NS). CONCLUSION: Budesonide enema 2 mg o.d. appears to be the optimal dosage in active distal UC. We could not show that budesonide enema twice weekly is sufficient to maintain remission.

Reduction of free radical activity in amyloid deposits following liver transplantation for familial amyloidotic polyneuropathy.

OBJECTIVES: Liver transplantation halt the progress of familial amyloidotic polyneuropathy (FAP). Oxidative stress has been implicated in amyloid toxicity and formation. The objective of this study was to establish whether markers for oxidant stress and antioxidant capacity change following liver transplantation in patients with FAP. DESIGN: Morphometric and biochemical study. SETTING: Tertiary referral centre. SUBJECTS: Duodenal biopsy samples from 16 patients, taken before and after liver transplantation were used for morphometry. Serum samples from 14 patients, seven of whom had received transplants, were analysed regarding antioxidant capacity. INTERVENTION: Liver transplantation. MAIN OUTCOME MEASURES: Immunohistochemistry was used to stain for the lipid peroxidation product 4-hydroxynonenal (HNE), and Congo red staining was used for amyloid detection. Positive areas were quantified by point counting. Total antioxidant capacity (TAC) was measured with a colourimetric assay. RESULTS: In tissue, a decrease of HNE was noted after liver transplantation, whereas no significant changes were detected for amyloid deposits. No difference between transplanted and not transplanted patients was noted for total antioxidant capacity measured in serum. CONCLUSION: To our knowledge, this is the first description of a reduction of markers for free radical activity after cessation of amyloid formation. The findings implicate that amyloid formation in transthyretin (TTR) amyloidosis generates oxidative stress, whereas amyloid deposits as such are less toxic to sourrounding tissues.

Comparison of amyloid deposits and infiltration of enteric nervous system in the upper with those in the lower gastrointestinal tract in patients with familial amyloidotic polyneuropathy.

Gastrointestinal (GI) complications in familial amyloidotic polyneuropathy (FAP) are invariably present during the course of the disease. The aim of this study was to investigate amyloid deposits in the myenteric plexus of the stomach and small intestine in FAP patients and compare the results with those of the colon. Six FAP patients were included in the study. The myenteric plexus and the number of macrophages (CD68) and blood vessels were immunostained and quantified by computerised image analysis. Double staining for amyloid and nerve elements was used to detect amyloid infiltration in the myenteric plexus. Amyloid was found predominantly in the walls of blood vessels, and was detected in the nerves of five FAP patients and in 18% of the examined ganglia of the myenteric plexus of the stomach. In the small intestine, 6% of examined ganglia showed amyloid deposits. In contrast, no deposits were found in the myenteric plexus of the colon. CD68-positive cells showed no difference in three parts of the GI tract. Most amyloid deposits were noted in the stomach, followed by the small intestine. There are significantly more blood vessels in the stomach and small intestine compared with the colon, and the amount of amyloid correlated with the number of blood vessels, and not with the amount of nerves and ganglia. The enteric nerve system is not a targeted organ for amyloid deposition in FAP.

Early liver transplantation is essential for familial amyloidotic polyneuropathy patients' quality of life.

Nineteen patients, who had undergone liver transplantation for familial amyloidotic polyneuropathy, had answered a quality of life questionnaire including 61 questions on somatic and mental symptoms, social aspects of life, confidence and satisfaction before, one year, and two years after transplantation. We found that patient satisfaction was generally good two years or more after the transplantation. Most of the patients were very or quite satisfied with the result. All of them had the drive to go on and felt hopeful about the future. However, on the second follow-up, 37% of the patients noted that they felt more insecure in their everyday life and there was a significant difference between the two assessments. The diarrhea score became worse between one and two years after the transplantation and was closely related to the duration of the gastrointestinal symptoms and to the duration of the disease before transplantation. The mental symptoms also increased significantly between the evaluations and this related to the severity of the somatic symptoms. Our conclusion is that liver transplantation should be performed before advanced somatic symptoms start to develop in order to improve the patients' chances of a good quality of life following liver transplantation.

Scavenger treatment of free radical injury in familial amyloidotic polyneuropathy: a study on Swedish transplanted and non-transplanted patients.

Since oxidative stress has been implicated in amyloid diseases, a study of scavenger treatment of hereditary transthyretin amyloidosis was undertaken on 23 familial amyloidotic polyneuropathy (FAP) patients. Nine patients had undergone a liver transplantation for the disease. Twenty patients completed the 6-month study period of scavenger treatment (vitamin C, 1 g, three times daily, vitamin E, 0.1 g, three times daily and acetylcysteine, 0.2 g three times daily). They were evaluated clinically and by immunohistochemical measurement of hydroxynonenal (HNE), a product of lipid peroxidation, in biopsy specimens. For non-transplanted patients, no improvement was found for HNE in relation to the amyloid content in biopsy specimens, whereas a tendency to a decreased amount was noted for transplanted patients. Clinically, no differences were found for non-transplanted patients, but an increased nutritional status, measured by a modified body mass index (mBMI) was noted for transplanted patients. In summary, scavenger treatment with the drugs and doses used in the present study appears to be unable to decrease lipid peroxidation in amyloid-rich tissue in non-transplanted FAP patients. For transplanted patients, lipid peroxidation tended to decrease, and the nutritional status measured by mBMI improved, even though the findings may be explained by liver transplantation alone, scavenger treatment may facilitate recovery after transplantation.

Outcome of gastrointestinal complications after liver transplantation for familial amyloidotic polyneuropathy.

BACKGROUND: Gastrointestinal disturbances are important prognostic factors for mortality and morbidity after liver transplantation for familial amyloidotic polyneuropathy (FAP). However, the impact of liver transplantation on malabsorption and bacterial small-bowel contamination has not been evaluated. METHODS: Twenty-three FAP patients were available for the study. They were examined for gastrointestinal disturbances as a part of the evaluation for liver transplantation for FAP. Bile acid malabsorption was diagnosed with the [75Se]-homocholic acid taurate (SeHCAT) test; fat malabsorption by measuring faecal fat excretion; and bacterial small-bowel contamination with the hydrogen breath test (HBT). RESULTS: No significant improvement of malabsorption test results were noted from the pre-transplant evaluation 8 months (range, 2-20 months) before transplantation to the post-transplant evaluation performed a median of 20 months (range, 9-62 months) after the procedure. The SeHCAT test result became abnormal in two patients and normal in one, and changes in the test correlated with the time the patients were waiting for transplantation. Faecal fat excretion after transplantation correlated with duration of the disease and with fat excretion before transplantation. A significantly increased fat excretion was noted at the post-transplant evaluation. A change in HBT result was noted in only one patient, in whom the test result became normal; pre-transplant values correlated with those obtained after transplantation. CONCLUSION: For most FAP patients no improvement in gastrointestinal function was found after transplantation. The finding underlines the importance of an early transplantation before the patients have developed gastrointestinal dysfunction.