P335Prevalence of transthyretin cardiac amyloidosis in a community-based heart failure population

Introduction

Cardiac wild type (wt) transthyretin (ATTR) amyloidos causes hypertrophic, restrictive cardiomyopathy in older patients and is generally considered underdiagnosed. However, its prevalence remains poorly investigated. Scintigraphy using bone tracers, e.g. Tc-PYP and Tc-DPD, is a highly sensitive and specific method for detection of cardiac ATTR and has revolutionised diagnostics The aim of this study was to describe the prevalence of wtATTR amyloidosis in our heart failure population.

Methods

Our University Hospital is the sole provider of specialised heart care in an area with around 150 000 inhabitants, 37 600 of which are older than 60 years. Medical records for all living patients in the area with a diagnosis of heart failure, hypertensive heart disease or cardiomyopathy between 2010 and May 2018 were scrutinized (n=2237). 95% of these patients had an echocardiographic exam available for re-evaluation. All patients withseptal thickness >14 mm who had no previous DPD scintigraphy or genetic diagnosis of sarcomeric hypertophic cardiomyopathy were offered DPD scintigraphy (n=131). Eight patients died prior to and 38 patients declined work up, mainly due to old age.

A DPD uptake of grade 2 or higher was considered diagnostic in absence of signs of AL amyloidosis.

Results

Adding up patients found during the screening effort and those with an already known diagnosis of wtATTR amyloidosis, 26 patients had wtATTR. Their men age was 84 years and 90% were male.

Conclusions

The study gives us an estimated prevalence of disease warranting specialized heart failure treatment of 1/1500 in the population older than 60 years. Cardiac wtATTR amyloidosis is common in patients with heart failure and increased LV wall thickness, especially among the older male patients. Therefore we recommend a liberal use of bone scintigraphy in this group.

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.

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.

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.

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.

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.

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.

Liver transplantation restores endocrine cells in patients with familial amyloidotic polyneuropathy

BACKGROUND

The aim of this study was to investigate familial amyloidotic polyneuropathy, Portuguese type patients' endocrine cell content in the stomach and duodenum before and after liver transplantation, and to relate the findings to the patients' gastrointestinal disturbances.

METHODS

Ten liver-transplanted familial amyloidotic polyneuropathy, Portuguese type patients and 10 healthy controls were seen. Endocrine cells were identified by immunohistochemistry and quantified with computerized image analysis. The activity of the cells was appraised by measurements of the cell secretory index and nuclear area. Clinical symptoms were obtained from the patients' medical records.

RESULTS

After transplantation, a significant increase of several endocrine cell types were noted, and the pretransplant depletion of several types of endocrine cells disappeared. For no type of endocrine cell was any difference compared with controls noted after transplantation. There was no significant decrease of the amount of amyloid in the biopsies after liver transplantation. The patients' symptoms remained generally unchanged after transplantation, although a substantial time lapse between pretransplant evaluation and transplantation was present.

CONCLUSIONS

Liver transplantation restores the endocrine cells in the upper part of the gastrointestinal tract. The restoration was not correlated with an improvement of the patients' symptoms. No decrease of the amyloid deposits was noted.

Heart failure caused by a novel amyloidogenic mutation of the transthyretin gene: ATTR Ala45Ser

Cardiac failure in transthyretin (TTR) amyloidosis patients has been shown to be caused by different mutations in the TTR gene. In the present case, a 73-year-old man from Northern Sweden was evaluated for heart failure. Amyloid deposits were found in subcutaneous fat and in intestinal biopsies. The presence of a variant form of TTR was detected in the plasma by electrospray ionisation mass spectrometry (ESI-MS). The mutation was located by single-strand conformation polymorphism (SSCP) analysis of the TTR gene where a band shift was seen in exon 2. Direct sequencing of exon 2 revealed a single base-pair substitution (G1724T). This transversion results in an amino acid substitution at codon 45, alanine to serine (ATTR Ala45Ser). Mass spectrometry analysis excluded that the variant is a polymorphism, since no similar shift in molecular weight has been present in more than 200 control samples. Congo red and immunostaining of duodenum biopsy specimens confirmed the presence of systemic ATTR amyloidosis, and clinical examination, including echocardiography, found evidence of a restrictive cardiomyopathy. He had 10 years previously been operated for a bilateral carpal tunnel syndrome, but otherwise no symptoms were present that could be attributed to his systemic amyloidosis. No axonal polyneuropathy was noted at nerve conduction studies. This novel mutation is the second amyloidogenic TTR mutation found in the Swedish population.

Enhancement of AA-amyloid formation in mice by transthyretin amyloid fragments and polyethylene glycol

The mechanism behind amyloid formation is unknown in all types of amyloidosis. Several substances can enhance amyloid formation in animal experiments. To induce secondary systemic amyloid (AA-type amyloid) formation, we injected silver nitrate into mice together with either amyloid fibrils obtained from patients with familial polyneuropathy (FAP) type I or polyethylene glycol (PEG). Mice injected with silver nitrate only served as controls. Amyloid deposits were detectable at day 3 in animals injected with amyloid fibrils and in those injected with PEG, whereas in control mice, deposits were not noted before day 12. Our results indicate that amyloid fibrils from FAP patients and even a non-sulfate containing polysaccharide (PEG) have the potential to act as amyloid-enhancing factors.

Endocrine cells in the upper gastrointestinal tract in relation to gastrointestinal dysfunction in patients with familial amyloidotic polyneuropathy

Gastrointestinal (GI) dysfunction is a common complication of familial amyloidotic polyneuropathy (FAP). In previous reports, a decreased content of small and large intestinal endocrine cells has been found in patients with FAP and it has been suggested that this may contribute to the development of GI disturbances. The aim of the present study was to investigate the endocrine cell content in the stomach and duodenum of FAP patients, and to correlate the findings with gastric emptying. Fifteen patients with FAP were included in the study. Twenty-eight subjects with macroscopically and histologically normal mucosa were used as controls for endocrine cell contents and 14 healthy subjects for gastric scintigraphy. The endocrine cells were identified by immunohistochemistry and quantified with image analysis. Gastric emptying time was detected by scintigraphy and endoscopy. The number of chromogranin A-immunoreactive (IR) cells was reduced in all investigated parts of the GI tract except bulbus duodeni. Gastrin/CCK cell content was reduced in duodenum, but tended to be increased in antrum of the stomach (P = 0.07). Otherwise, the content of all other endocrine cells types in the upper GI tract was reduced compared with controls. A correlation with malnutrition was found for gastric inhibitory polypeptide and secretin cell content in bulbus duodeni. Gastric scintigraphy disclosed delayed gastric emptying of solid food, but the finding was not correlated to the decreased content of neuroendocrine cells. The severity of endocrine cell depletion was not correlated to duration of GI disturbances. The present study showed that the endocrine cells of the stomach are affected in FAP patients and that the abnormalities in the upper GI endocrine cells occur early during the course of the disease.

Colonic enteric nervous system in patients with familial amyloidotic neuropathy

The colonic enteric nervous system was investigated in autopsy specimens from 12 patients with familial amyloidotic neuropathy (FAP) and 9 controls. The infiltration of amyloid deposits in the enteric nervous system was studied by double staining for amyloid and nerve elements. The myenteric plexus was immunostained for protein gene product (PGP) 9.5, vasoactive intestinal peptide (VIP), substance P and nitric oxide synthase (NOS). The immunostained nerve elements were quantified by computerised image analysis. Double staining revealed that there was no amyloid infiltration in the ganglia, or in the nerve fibres in the colonic enteric nervous system of FAP patients. The relative volume density of PGP 9.5-immunoreactive nerve fibres in both the circular and the longitudinal muscle layers in FAP patients did not differ significantly from that of controls. The relative volume density of VIP-immunoreactive nerve fibres in the circular muscle layer was significantly decreased in FAP patients compared with controls, but not in the longitudinal layer. The number of VIP-immunoreactive neurons/mm2 myenteric ganglia was significantly decreased in FAP patients. There were no statistical differences in the relative volume density for substance P- and NOS-immunoreactive nerve fibres between FAP patients and controls, nor was there any difference between FAP patients and controls regarding the number of NOS- and substance P-immunoreactive neurons/mm2 myenteric ganglia. It is concluded that the colonic enteric nervous system as a whole is intact and is not damaged by amyloid infiltration. The present observation of a reduction of VIP-immunoreactive nerve fibres and neurons in myenteric plexus of FAP patients might be one of the factors that contribute to the motility disorders seen in FAP patients.

Colonic endocrine cells in patients with familial amyloidotic polyneuropathy

OBJECTIVE

To establish whether the endocrine cell number is affected in the colon in Japanese FAP patients.

SETTING

Department of Medicine, Umeå University Hospital and Department of Internal Medicine and Pathology, University Hospital, Kumamoto, Japan.

SUBJECTS

Autopsy colon tissue specimens from 11 FAP patients and nine controls as well as 12 control biopsy specimens were included in the study.

MEASUREMENTS

Endocrine cells in the colon were detected by immunohistochemistry and quantified by computerized image analysis.

RESULTS

The autopsy material showed a slight autolysis. Neither enteroglucagon nor pancreatic polypeptide positive cells could be detected in the autopsy material, but were present in biopsy material. There was no statistical difference between autopsy and biopsy specimens regarding the number of peptide YY (PYY), somatostatin and serotonin cells. No significant differences were noted in PYY, somatostatin and serotonin immunoreactive cells in FAP patients compared to autopsy controls, though PYY cells tended to be decreased and serotonin and somatostatin cells tended to be increased in FAP patients.

CONCLUSION

The difference between the Swedish and Japanese patients in the endocrine cell content points to the possibility of involvement of other factors than the endocrine cell depletion of the colon might be involved in the pathogenesis of gastro-intestinal dysfunction in FAP. The tendency of PYY to decrease in Japanese FAP might contribute to the development of diarrhoea in these patients.