Intissar Anan

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.

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 natisea 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 (≥ 4 years) is unchanged after liver transplantation.

Colonic enteric nervous system in patients with familial amyloidotic neuropathy.

Abstract 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.

Serum transthyretin levels in Swedish TTR V30M carriers

Serum transthyretin (TTR) levels have been reported to be reduced in Portuguese and Japanese patients with TTR V30M familial amyloidotic polyneuropathy and pre-symptomatic carriers of the allele as well as in the carriers of a number of other mutant TTRs. The only published report of serum TTR levels in Swedish TTR V30M carriers suggested that serum TTR levels were elevated in a small number of cases. Since Swedish V30M carriers have a lower degree of clinical penetrance than those from other countries we wished to determine if the reportedly elevated serum TTR concentrations and the lower clinical penetrance were part of a pathologic process that differed between the Swedish carriers and those of other ethnic groups. We compared the serum TTR levels, as determined by ELISA, in 42 documented Swedish TTR V30M carriers with 16 control individuals from the same geographic area in northern Sweden. Serum TTR concentrations in the controls were statistically significantly higher than in the TTR V30M carriers, which were in the same range as those in African-Americans carrying the TTR V122I allele. Thus, Swedish TTR V30M carriers have the same reduction in serum TTR as do other ethnic groups carrying the same or other TTR mutations.

Advanced glycation end products (AGE) and the receptor for AGE are present in gastrointestinal tract of familial amyloidotic polyneuropathy patients but do not induce NF-kappaB activation.

Abstract. Familial amyloidotic polyneuropathy (FAP), Portuguese type, is a hereditary amyloidosis caused by mutated transthyretin (ATTR) in which an exchange of valine for methionine at position 30 has taken place (ATTR Val30Met). Gastrointestinal complications, such as nausea, diarrhoea and malabsorption, have a significant impact on survival since the cause of death in the majority of cases is a consequence of extreme malnutrition due to dysmotility of the gastrointestinal tract. Recently, a role of the receptor for advanced glycation end products (RAGE) has been implicated in amyloid toxicity. Transthyretin (TTR) amyloid fibrils have been shown to have affinity for RAGE and subsequently induce NF-κB activation and apoptosis. Since gastrointestinal dysfunction plays an important role in FAP, we wanted to investigate if amyloid toxicity in the gastrointestinal tract is related to RAGE, NF-κB activation and apoptosis. Gastrointestinal tract autopsy samples were studied for the distribution of amyloid, RAGE, advanced glycation end products (AGE) and NF-κB. Furthermore, we examined the immunoreactivity of an apoptotic marker to investigate if an apoptotic pathway contributes to amyloid toxicity. The distribution of RAGE and AGE strongly correlated to that of amyloid deposits. Sequential immunofluorescence staining revealed a clear relationship between TTR, AGE and RAGE. No correlation between NF-κB, apoptotic marker and amyloid deposits was found. We conclude that RAGE-AGE or RAGE-TTR interaction might play important roles for gastrointestinal dysfunction and amyloid toxicity, although not through NF-κB activation and apoptosis.

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.

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 (ATTRAla45Ser). 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.

Colonic endocrine cells in patients with familial amyloidotic polyneuropathy

Abstract. Anan I, El‐Salhy M, Ando Y, Nyhlin N, Terazaki H, Sakashita N, Suhr O (University Hospital, Umeå, Sweden, and University Hospital, Kumamoto, Japan). Colonic endocrine cells in patients with familial amyloidotic polyneuropathy. J Intern Med 1999; 245: 469–473.

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.

Abstract. 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.

Liver transplantation restores endocrine cells in patients with familial amyloidotic polyneuropathy.

Background. The aimof 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.