Impact of gastrointestinal dysfunction on survival after liver transplantation for familial amyloidotic polyneuropathy

Liver transplantation is the only effective treatment of familial amyloidotic polyneuropathy type I (FAP). The aim of the present investigation was to identify factors at the time of submission for transplantation that had impact on survival, with special reference to gastrointestinal disturbances. All 28 liver-transplanted FAP patients evaluated at Umeå University Hospital were included in the study. A modified body mass index was used to assess nutritional status. Intestinal examinations were performed to diagnose bile acid malabsorption, gastric retention, and bacterial contamination of the small bowel. A significantly improved survival rate was found for patients in a good nutritional state (P = 0.002). Peripheral neurological symptoms were unrelated to survival, whereas increased mortality was found for patients with bile acid malabsorption (P < 0.05). Bacterial contamination and gastric retention were common complications of the disease. In conclusion, malabsorption and malnutrition have a profound impact on the outcome of liver transplantation for familial amyloidotic polyneuropathy.

Daytime glibenclamide and bedtime NPH insulin compared to intensive insulin treatment in secondary sulphonylurea failure: a 1-year follow-up

The aim of this study was to compare the metabolic effects of a combination of daytime glibenclamide and evening NPH insulin with intensive insulin treatment (rapid acting insulin before meals and NPH insulin at bedtime) in patients exhibiting secondary failure to sulphonylurea treatment. Thirty-nine mildly obese NIDDM patients (BMI 25.6 +/- 0.5) were randomized after 6 weeks of intensive insulin treatment to either a combination treatment (CT, n = 20) or continued intensive insulin treatment (IT, n = 19). There were no differences between the two groups in age, diabetes duration, BMI, HbA1c, or basal and glucagon stimulated C-peptide. The patients were followed for 1 year and the findings were analysed on an intent to treat basis. Two patients in the CT group were excluded after 2 and 6 months, respectively, due to unacceptably high postprandial glucose values. There was a significant difference in HbA1c between the CT and IT groups at 6 months (8.2 +/- 0.2, n = 19, vs 6.8 +/- 0.4%, n = 19, p < 0.001)), but not at 12 months (7.8 +/- 0.3, n = 18, vs 7.5 +/- 0.4%, n = 19). After the initial intensive insulin treatment, BMI was constant in the CT group but increased significantly at 6 and 12 months in the IT group. We conclude that both treatments are associated with a marked and long-term improvement of glycaemic control. The intensive insulin treatment leads to a more pronounced weight increase which in the long run might have negative effect on overall metabolic control. Therefore, the combination treatment together with intensified education and dietary advice should be regarded as the initial treatment of choice for oral agent failure in moderately obese NIDDM patients.

Liver transplantation in familial amyloidotic polyneuropathy. Follow-up of the first 20 Swedish patients

Familial amyloidotic polyneuropathy (FAP) is an inherited fatal form of amyloidosis caused by mutant transthyretin. The disease is characterized by progressive peripheral and autonomic neuropathy. Most of the transthyretin is produced by the liver, and we have shown previously that the metabolic deficiency can be corrected by liver transplantation. In the present study, the clinical results from the first 20 patients who underwent liver transplantation for FAP in Sweden are evaluated. Three of the patients suffered from renal failure and underwent a simultaneous kidney transplantation. Fourteen of the 20 patients (70%) are alive 10-52 months after transplantation. The patients' nutritional status at the time of transplantation had a significant impact on mortality and morbidity (P < 0.007). Long-standing disease was another negative prognostic factor (P < 0.02). One year after transplantation, the nutritional status had improved (P < 0.02). Improvements were also noted in walking capacity and for gastrointestinal and urogenital symptoms. The results show that liver transplantation offers an effective means to treat patients with FAP. The procedure should preferably be performed before the nutritional status is poor and advanced organ dysfunction has developed.

Occupational and other risk factors for clinically overt familial amyloid polyneuropathy

Amyloidosis is associated with the deposition of amyloid substance in various tissues of the body. In several forms of familial amyloid polyneuropathy, mutated transthyretin is the main fibril component. The disease is inherited as an autosomal dominant trait with onset in adult life, but few carriers develop symptoms. The aim of the present investigation was to screen for additional factors that might be necessary for the development of familial amyloid polyneuropathy. We conducted a case-control study involving 51 male and 30 female cases of clinically overt familial amyloid polyneuropathy and 306 male and 317 female population controls. We considered occupational exposures, disease histories, and medical treatments as potential determinants of risk for clinically overt disease. We found an odds ratio of 5.4 for dressmakers. Low and high levels of exposure to organic solvents resulted in an odds ratio of 2.1 and 11.8, respectively. A history of prostatic hyperplasia, cholecystic disease, or appendectomy was also a risk factor, possibly as a consequence of anesthesia.

Malnutrition and gastrointestinal dysfunction as prognostic factors for survival in familial amyloidotic polyneuropathy

OBJECTIVES

To describe the evolution of nutritional and neurological complications in a Swedish population of patients with familial amyloidotic polyneuropathy, and to identify prognostic factors and useful tests for monitoring the progress of the disease.

DESIGN

Prospective and retrospective study of patients with familial amyloidotic polyneuropathy.

SETTING

Tertiary referral centre.

SUBJECTS

Twenty-seven patients with familial amyloidotic polyneuropathy, and a symptomatic onset before the age of 50.

MAIN OUTCOME MEASURES

Age at onset, duration of disease before death, serum albumin, body mass index (BMI), duration and grade of peripheral neuropathy and gastrointestinal disturbances. Faecal fat, xylose test and 75selenohomocholic acid-taurine (SeHCAT) test were used for assessment of malabsorption.

RESULTS

Thirteen patients died during the study period after a disease duration of between 9 and 18 years (mean 13). A short time interval between the onset of neurological and of gastrointestinal symptoms had greater impact on survival than age at onset in this selected group of patients (r = 0.65; P = 0.017). Malnutrition was evaluated by multiplying the [body weight (kg)/height2 (m)] with the serum albumin to compensate for oedema. This modified body mass index (mBMI) was significantly correlated to the number of years before death (r = 0.89; P < 0.0005) and to the duration of gastrointestinal symptoms (r = -0.66; P < 0.0005), but not to duration of disease (r = -0.2; P = 0.20). Polyneuropathy was graded according to functional capacity from I to IV (PND score) and was correlated to the number of years before death and mBMI, but not to serum albumin. The SeHCAT test for bile acid malabsorption was significantly correlated to the duration of gastrointestinal symptoms and to mBMI (r = -0.67; P = 0.0003 and r = -0.62; P = 0.003, respectively).

CONCLUSION

The investigation disclosed that a short time interval between the onset of neurological and of gastrointestinal symptoms is associated with a decreased survival time. The mBMI was closely related to time before death, duration of gastrointestinal disturbances, malabsorption and functional capacity. The mBMI appears to be well suited to monitoring disease progress and gives prognostic information.

Geographical distribution of TTR met30 carriers in northern Sweden: discrepancy between carrier frequency and prevalence rate

The first Swedish case of familial amyloidotic polyneuropathy (FAP) was published in 1965. The same transthyretin (TTR met30) mutation as that seen in Japanese, Portuguese, and other populations was also found in Swedish FAP patients. More than 350 patients with clinical manifestations of FAP have been diagnosed in northern Sweden, most of them originating from the areas around Skellefteå and Piteå. The mean age of onset is 56 years, much later than in patients from Japan and Portugal. To estimate the frequency of the TTR met30 mutation in the counties of Västerbotten and Norrbotten, sera from 1276 persons aged 24 to 65 years, randomly sampled from a health programme (MONICA), were screened with the monoclonal antibody FD6. In 19 persons, 13 females and six males, a positive reaction was seen in an Elisa test using this antibody. DNA analysis confirmed the TTR met30 mutation and showed that 18 were heterozygous and one homozygous for this mutation. Other mutations were not looked for in this study. The mean TTR met30 carrier frequency in the area was 1.5% ranging from 0.0 to 8.3% in 23 subpopulations. There was a notable discrepancy between the regional distribution of the TTR met30 allele and the morbidity rate for FAP. The estimated number of TTR met30 gene carriers in a total population of 500,000 in the area is approximately 7500. The penetrance of the TTR met30 mutation shows considerable variation between families, and the overall diagnostic (predictive) value in this population is as low as around 2%.

Clinical improvement and amyloid regression after liver transplantation in hereditary transthyretin amyloidosis

Familial amyloid polyneuropathy (FAP) is a fatal autosomal dominant disorder. Progressive peripheral and autonomic neuropathy are associated with neural and visceral deposition of amyloid, derived most commonly from the Met-30 variant of the plasma protein transthyretin. We have reported previously that orthotopic liver transplantation causes prompt replacement of variant transthyretin by the donor wild-type in the plasma. We now report clinical outcome 1-2 years after transplantation. Three of the first four patients have improved general wellbeing, walking ability, and bowel function, and one of them has regained normal bladder and bowel function. There has been little objective improvement in peripheral neuropathy. The fourth patient, who had the most severe neurological deficits and a complicated postoperative course, has not improved but there has been no further deterioration in contrast to the inexorable progression before transplantation. Quantitative scintigraphy with radiolabelled serum amyloid P component showed visceral amyloid deposits in all three patients studied; in two who were followed serially the deposits regressed after transplantation in association with the clinical improvement. Another FAP patient who was also monitored prospectively for 2 years but who did not undergo transplantation, showed, as expected, progression of neuropathy and increased visceral amyloid deposition. Liver transplantation does therefore have important benefits in FAP during the first 2 years after surgery. Neurological decline is halted and amyloid deposits can be mobilised. The best timing and long-term results of the procedure must now be established.

The x-ray crystal structure refinements of normal human transthyretin and the amyloidogenic Val-30-->Met variant to 1.7-A resolution

The x-ray crystal structures of normal human transthyretin (prealbumin) and the amyloidogenic Val-30-Met variant have been refined at 1.7-A resolution to R-values of 0.168 and 0.179, respectively, for 19,882 and 20,362 reflections (Fobs > 2.0 sigma). Standard deviations for stereochemical parameters are 0.018 and 0.022 A for bond distances, 0.030 and 0.038 A for angle distances, and 0.035 and 0.070 A for planar 1-4 distances. The newly refined normal structure shows improvement over the original structure of Blake and Swan (Blake, C. C. F., and Swan, I. D. A. (1971) J. Mol. Biol. 61, 217-224) in stereochemistry and in the conformation of the loop regions. Residues Arg-103, Thr-123, Asn-124, and Pro-125 have now been resolved, and residues 1-9 and 126-127 have been modeled with the aid of simulated annealing refinement. The functional form of transthyretin is a tetramer, having a cylindrical cavity which will bind thyroxine and an exterior binding site for the complex of retinol with retinol-binding protein. The monomer is a beta barrel flattened to become more like a sandwich with residue 30 in the interior. The methionyl for valyl substitution forces the beta sheets of the monomer as much as 1 A apart, resulting in a distortion of the thyroxine-binding cavity, in agreement with the independent observations that the Met-30 variant has low affinity for thyroxine.

Diagnostic radioimmunoassay and DNA-analysis in Swedish and Japanese patients with familial amyloidotic polyneuropathy. Homozygosity for the TTR met30 gene

Eighteen Swedish patients with familial amyloidotic polyneuropathy were tested for the met30 mutation of the transthyretin (TTR) (prealbumin) gene by RFLP analysis of genomic DNA using the restriction enzyme NsiI. The results confirmed previous findings that the Swedish variant of familial polyneuropathy has the same valine by methionine substitution at position 30, as seen in patients with FAP from Japan, Portugal or patients of Swedish descent from USA. However, two of the patients were homozygous, totally lacking the wild type allele. Measurable serum values for the variant transthyretin (TTR) was detected with a RIA-method in all the 18 Swedish FAP patients studied with a mean concentration of 12.1 +/- 5.1 (SD) mg/100 ml, (11.0 +/- 4.1 when the two homozygotes were excluded). In 45 Japanese patients the mean was 9.2 +/- 2.7 mg/100 ml. The variant TTR was not detected in the healthy controls. The value for the variant TTR was nearly twice that high in the two homozygous patients, 21.14 and 21.16 mg/100 ml, respectively. There was no correlation between the serum levels of variant TTR and the duration of disease or levels of serum albumin in the FAP-patients.

Oesophageal dysfunction in familial amyloidosis with polyneuropathy

Sixteen patients with familial amyloidosis and polyneuropathy (FAP) and 14 health subjects underwent oesophageal manometry. Six of the patients had a severe oesophageal dysmotility with almost completely abolished propulsive pressure waves on swallowing in the lower 2/3 of the oesophagus. Ten patients had moderate dysfunction with reduced propulsive pressure wave amplitudes. Neostigmine increased the pressure wave amplitudes in healthy subjects but less so in the FAP patients. Scopolamine (Scopyl)-terbutaline (Bricanyl) almost abolished the propulsive pressure waves in healthy subjects and all patients in the lower 2/3 of the esophagus. Oesophageal distensibility, tested by inflating a rubber balloon in the oesophagus, was similar in FAP patients and healthy subjects. Thus, it is unlikely that amyloid deposits in the mucosal wall increased the oesophageal stiffness. An autonomic, predominantly vagal, denervation probably explains the disturbed function.

Salivary hypofunction in patients with familial amyloidotic polyneuropathy

Patients who suffer from familial amyloidotic polyneuropathy frequently complain of mouth dryness and an increased need for dental treatment. The aim of the present investigation was to study saliva secretion rate and composition and other factors related to the risk of dental caries in patients with familial amyloidotic polyneuropathy. Thirty patients with familial amyloidotic polyneuropathy volunteered for the study and were compared with a matched control group. Samples of unstimulated and stimulated whole saliva were collected in a standardized manner. The secretion rates were calculated, and the concentrations of electrolytes, glycoprotein markers, and proteins with antibacterial properties were analyzed. Dental caries and variables related to the risk of dental caries were also scored. The results show that familial amyloidotic polyneuropathy patients frequently have a decreased rate of saliva secretion and that the degree of salivary hypofunction is positively correlated to the progress of familial amyloidotic polyneuropathy. Forty-three percent of the familial amyloidotic polyneuropathy patients in this study had no detectable secretion of unstimulated saliva. A low secretion rate of stimulated saliva (< 0.7 ml/min) was found in 33% of the patients. The concentrations of salivary protein, amylase, lysozyme, salivary peroxidase, secretory IgA, hexosamines, sialic acid, fucose, phosphate, potassium, and the degree of protein glycosylation were higher in the familial amyloidotic polyneuropathy patients than in the control patients. We conclude that patients with familial amyloidotic polyneuropathy have a reduced saliva secretion and are subsequently at risk for increased development of dental caries.

Alteration in molecular structure which results in disease: the Met-30 variant of human plasma transthyretin

The structure of a variant transthyretin has been determined by X-ray crystallography at 2.3 A resolution in order to investigate those changes which lead to amyloid formation. This variant transthyretin, in which the internal valyl residue at position 30 is replaced by methionyl, is associated with the most common form of familial amyloidotic polyneuropathy (FAP). Comparison to the known structure of the normal transthyretin tetramer shows that the bulkier methionine residue 30 which lies between the nearly orthogonal beta sheets of the dimer, results in the sheets being displaced an average of 0.4 A. The internal structure of the sheets and of the monomer-monomer interface is maintained. Such global changes may affect the metabolic properties and the tendency towards polymerization of the mutant protein. These findings may form a basis for understanding other amyloid-deposition diseases.

Bile acid malabsorption caused by gastrointestinal motility dysfunction? An investigation of gastrointestinal disturbances in familial amyloidosis with polyneuropathy

Gastrointestinal dysfunction due to autonomous neuropathy is a complication described in various diseases such as diabetes mellitus, multiple sclerosis, and familial amyloidosis with polyneuropathy. We present the results of a prospective investigation of bile acid malabsorption in 17 patients with familial amyloidosis by means of 75Se-labelled homocholic-tauro acid (SeHCAT). The diagnosis was in all cases verified by the DNA test for mutation of transthyretin in position 30. Small-intestinal biopsy specimens were examined for deposits of amyloid, and the presence of gastric retention was evaluated by gastroscopy. In addition, the patients were investigated for bacterial overgrowth by means of the bile acid breath test (BABT). A high frequency of abnormal BABT results (44%) was encountered. However, 65% also had abnormal low SeHCAT values, indicating bile acid malabsorption. Only two patients had abnormal BABT and normal SeHCAT results, indicating bacterial contamination of the small intestine. Bile acid losses increased with the duration of gastrointestinal symptoms. Significantly lower SeHCAT values were encountered in patients with gastric retention, whereas the occurrence of amyloid deposits in small-intestinal biopsy specimens was without effect on SeHCAT retention. Bile acid malabsorption is frequently encountered in familial amyloidosis with polyneuropathy and seems to be more closely associated with gastrointestinal motility dysfunction than with amyloid deposits in the intestinal mucosa.

Biochemical effect of liver transplantation in two Swedish patients with familial amyloidotic polyneuropathy (FAP-met30)

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant inherited disorder characterized by progressive peripheral and autonomic neuropathy, associated with neural and systemic amyloid deposits. The amyloid fibrils contain a variant transthyretin (TTR) molecule (TTR met30), over 90% of which is produced in the liver. After liver transplantation in two patients with severe symptomatic FAP, only normal TTR was detectable in circulation. The two patients are being monitored at regular intervals, and, although in one patient there was no evidence of reduction in the quantity of amyloid present at 6 months, there had been no further progression of the neuropathy.

Association of C3 and C4A complement types with familial amyloidotic polyneuropathy

A mutant variant of the serum protein transthyretin (TTR-met30) appears to be a necessary but not sufficient condition for the development of familial amyloidotic polyneuropathy (FAP). We have studied a number of serum protein markers (alpha 1-antitrypsin, properdin factor B, C3, C4A, C4B, haptoglobin, transferrin and group-specific component) in FAP patients and healthy controls in an attempt to identify additional pathogenic factors which may influence the risk for developing FAP in male and female patients as well as the age of onset of the disease. Statistically significant associations were found in the complement systems C3 and C4A. The C3F variant was significantly increased in all FAP patients with a relative risk (RR) of 2.0, more pronounced in female patients (RR = 2.6) and patients with an early onset of the disease (RR = 4.5). In the FAP patients only the variants A3 and A4 were found in the C4A system. C4A3 was found in all patients, which was significantly higher than in the controls. The remaining serum protein systems showed no statistically significant associations with FAP. The results suggest that genetic variants of complement factors C3 and C4A may interact with the mutant TTR-met30 by modifying the expression and onset of FAP.

Homozygosity for the transthyretin-met30-gene in two Swedish sibs with familial amyloidotic polyneuropathy

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant inherited disorder. Recent biochemical studies have revealed that amyloid protein in FAP of Japanese, Swedish and Portuguese origin mainly consists of a variant transthyretin (TTR) (formerly called prealbumin) with one amino acid substitution of methionine for valine at position 30. In a 56-year-old man with typical polyneuropathy, gastrointestinal problems and vitreous amyloid, we diagnosed homozygosity for the TTR-met30-gene using RFLP analysis. In a family study, a sister presented the same homozygous RFLP pattern; however, in a careful clinical investigation we were not able to demonstrate any of the typical symptoms of FAP, nor could we demonstrate amyloid deposits in a biopsy skin specimen. This is the first report of homozygosity for the TTR-met30-gene, and it shows that the mutation of the protein involved in amyloid formation may be necessary but is clearly not sufficient for the clinical symptoms.

Restriction fragment length polymorphism analysis of mutated transthyretin in vitreous amyloidosis

Amyloid deposits of the vitreous are usually associated with familial amyloidotic polyneuropathy (FAP). Various mutated forms of transthyretin (prealbumin) seem to form the main amyloid fibril component. Five Swedish patients, all with vitreous amyloidosis but no systemic symptoms or family history of amyloidosis, were examined using restriction fragment length polymorphism analysis. Genomic DNA was tested with a transthyretin complementary DNA probe. After cleavage with Nsi1, two restriction fragment length polymorphism markers of 5.1 and 1.5 kilobase were detected in the patients but not in the control subjects. These observations indicate the same methionine for valine substitution at position 30 of the transthyretin molecule in patients with vitreous amyloidosis as seen in Swedish patients with FAP as well as in patients with FAP from Japan and Portugal, and patients of Swedish descent with FAP from the United States.

Diagnosis of familial amyloidotic polyneuropathy in Sweden by RFLP analysis

Genomic DNA from 17 Swedish patients with familial amyloidotic polyneuropathy (FAP), and 50 healthy controls were tested with a cDNA transthyretin probe. In seven of the patients, FAP was not reported in either of their parents. All 50 controls showed restriction fragments of 6.6 kb and 3.2 kb after cleavage with Nsil, while the 17 FAP patients showed RFLP markers of 5.1 and 1.5 kb. These observations indicate the same methionine for valine substitution at position 30 in Swedish patients with FAP as seen in patients with FAP from Japan, Portugal and FAP-patients of Swedish descent from USA. However, the mean onset of FAP symptoms for the 17 Swedish patients was found to be significantly later than for the patients from Japan, Portugal and USA.