Domino hepatic transplantation using the liver from a patient with familial amyloid polyneuropathy

BACKGROUND: In transplantation, novel methods are required to augment the supply of donor organs. We report the first domino liver transplant in which a patient with familial amyloid polyneuropathy (FAP) received an orthotopic split liver graft, and her explanted liver was donated to another patient. Three successful liver transplants were thus achieved from the one cadaver liver. PATIENTS AND METHODS: A cadaveric donor liver was split and the left lobe was grafted into a child with biliary atresia. The right lobe was transplanted into a woman with FAP associated with the transthyretin Met30 variant. Her own otherwise healthy liver was donated to a patient with cirrhosis and hepatocellular carcinoma. RESULTS: Fifteen months after transplantation, all three recipients are well with normal liver function. The domino recipient developed inferior vena cava stricturing at the level of anastomosis after surgery with resultant ascites, requiring dilatation and LeVeen shunt insertion. Serum amyloid P component scintigraphy showed amyloid regression in the domino donor and to date has not identified any amyloid deposits in the recipient, who also remains free of tumor recurrence. CONCLUSIONS: Domino transplantation using the livers from patients with FAP may be justified for patients whose disease condition precludes a long spell on the waiting list, including those with hepatic malignancies and those for whom palliation rather than long-term cure is the aim.     

Diagnosis and treatment of postoperative chyle leakage via percutaneous transabdominal catheterization of the cisterna chyli: a preliminary study

BACKGROUND AND AIMS: The liver is frequently involved in amyloidosis but the significance of hepatic amyloid has not been systematically studied. We have previously developed scintigraphy with 123I serum amyloid P component (123I-SAP) to identify and monitor amyloid deposits quantitatively in vivo and we report here our findings in hepatic amyloidosis. METHODS: Between 1988 and 1995, 805 patients with clinically suspected or biopsy proven systemic amyloidosis were evaluated. One hundred and thirty eight patients had AA amyloidosis, 180 had AL amyloidosis, 99 had hereditary amyloid syndromes, and 67 had dialysis related (beta 2 microglobulin) amyloid. One hundred and ninety two patients with amyloidosis were followed for six months to eight years. RESULTS: Hepatic amyloid was found in 98/180 (54%) AL and 25/138 (18%) AA patients but in only 1/53 patients with familial transthyretin amyloid polyneuropathy and in none with dialysis related amyloidosis. There was complete concordance between hepatic SAP scintigraphy and the presence or absence of parenchymal amyloid deposits on liver histology. Amyloidosis was never confined to the liver. Mortality was rarely due to hepatic failure, although hepatic involvement with AA amyloid carried a poor prognosis. Successful therapy to reduce the supply of amyloid fibril protein precursors was followed by substantial regression of all types of amyloid. CONCLUSIONS: SAP scintigraphy is a specific and sensitive method for detecting and monitoring hepatic amyloid. Liver involvement is always associated with major amyloid in other organ systems and carries a poor prognosis in AA type. Appropriate therapy may substantially improve prognosis in many patients.     

Analysis of amyloid deposition in a transgenic mouse model of homozygous familial amyloidotic polyneuropathy

Amyloid fibrils derived from the Japanese, Portuguese, and Swedish types of familial amyloidotic polyneuropathy all consist of a variant transthyretin (TTR) with a substitution of methionine for valine at position 30 (TTR Met 30). In an attempt to establish an animal model of TTR Met-30-associated homozygous familial amyloidotic polyneuropathy and to study the structural and functional properties of human TTR Met 30, we generated a mouse line carrying a null mutation at the endogenous ttr locus (ttr-/-) and the human mutant ttr gene (6.0-hMet 30) as a transgene. In these mice, human TTR Met-30-derived amyloid deposits were first observed in the esophagus and stomach when the mice were 11 months of age. With advancing age, amyloid deposits extended to various other tissues. Because no significant difference was detected in the onset, progression, and tissue distribution of amyloid deposition between the ttr-/- and ttr+/+ transgenic mice expressing 6.0-hMet 30, endogenous normal mouse TTR probably does not affect the deposition of human TTR Met-30-derived amyloid in mice. TTR is a tetramer composed of four identical subunits that binds thyroxine (T4) and plasma retinol-binding protein. The introduction of 6.0-hMet 30 into the ttr-/- mice significantly increased their depressed serum levels of T4 and retinol-binding protein, suggesting that human TTR Met 30 binds T4 and retinol-binding protein in vivo. The T4-binding ability of human TTR Met 30 was confirmed by the analysis of T4-binding proteins in the sera of ttr-/- transgenic mice expressing 6.0-hMet 30. The T4-binding studies also demonstrated the presence of hybrid tetramers between mouse and human TTR subunits in the ttr+/+ transgenic mice expressing 6.0-hMet 30.     

Serum amyloid P component scintigraphy and turnover studies for diagnosis and quantitative monitoring of AA amyloidosis in juvenile rheumatoid arthritis

OBJECTIVE: To evaluate aspects of the natural history of AA amyloidosis complicating juvenile rheumatoid arthritis (JRA), and its response to therapy with chlorambucil. METHODS: Scintigraphy and 7-day turnover studies were performed in JRA patients with histologically proven (n = 35) or clinically suspected (n = 30) AA amyloidosis, following intravenous injection of 123I and 125I-labeled serum amyloid P component (SAP). Prospective monitoring studies were performed over 2-3 years in 20 patients with amyloidosis. All but 2 amyloidosis patients were treated with chlorambucil. RESULTS: Positive scanning results were obtained in all patients in whom imaging was performed within 12 years of positive biopsy findings of amyloid and in 5 patients with clinically suspected amyloidosis. Negative scanning results with normal SAP metabolism, indicating regression of amyloid, were obtained in 4 patients whose amyloidosis had been in full clinical remission for more than 12 years. Prospective monitoring studies in patients whose JRA-associated inflammatory activity was in remission demonstrated regression of amyloid in 8 patients and no substantial changes in 8 others; however, in 4 further patients with active inflammation, there was accumulation of amyloid. There was a very poor correlation between the amount of amyloid present at a particular site and the resultant organ dysfunction. CONCLUSION: Radiolabeled SAP scintigraphy and turnover studies are useful complementary tools in the diagnosis, screening, and quantitative monitoring of type AA amyloidosis in JRA. The amyloid deposits may progress and/or regress at different rates in different anatomic sites over short periods.     

A late onset familial amyloidotic polyneuropathy (FAP) with a novel variant transthyretin characterized by a basic-for-acidic amino acid substitution (Glu61-->Lys)

A 64-year-old man has suffered from intractable diarrhea since January 1990. He noticed numbness and weakness in the distal portion of four extremities in the following several months. His symptoms were gradually progressive. In June 1992, neurological examination revealed mild muscular atrophy and weakness in the proximal and distal portions of four extremities. There were paresthesia and severe impairment of superficial sensations in the lower limbs, lower half of the trunk and upper limbs. All deep tendon reflexes were reduced or absent. Autonomic dysfunctions such as orthostatic hypotension, impotence and diarrhea were evident. On sural nerve biopsy, myelinated fibers showing axonal degeneration were predominantly seen, and densities of both myelinated and unmyelinated fibers were markedly decreased. No amyloid deposits were found in the endoneurium. Amyloid deposition was identified in the gastric mucosa by Congo red staining and immunostaining with anti-transthyretin (TTR) antibody. Edman degradation showed one amino acid substitution of Lys for Glu at position 61 in the TTR-peptides from the serum. Direct DNA sequencing revealed a new point mutation in the 61st codon of TTR gene. The same point mutation of TTR gene was identified in the DNAs from his 67-year-old brother and 63-year-old sister and one of the paternal cousins, a 64-year-old woman, although their clinical symptoms and signs were negative. Clinical features such as late onset of the symptoms and signs and presence of carriers in their sixties in this family are unique and atypical as compared with those of more frequent Val30-->Met FAP families. A variant TTR, characterized by a Glu61-->Lys substitution (a basic-for-acidic amino acid substitution) found in this family, has not been reported in the literature. In the case of the examination of the patients with autonomic and sensory symptoms and signs of unknown etiology, amyloidotic polyneuropathies, including FAP even in the absence of the family history, should be differentiated. When FAP is highly suspected, the combination of family study and DNA analysis of a possible variant TTR is indispensable for the establishment of the diagnosis.     

A multiplex RT-PCR assay for analysis of relative transcript levels of different members of multigene families: application to Arabidopsis calmodulin gene family

In systemic amyloidosis, widespread amyloid deposition interferes with organ function, frequently with fatal consequences. Diagnosis rests on demonstrating amyloid deposits in the tissues, traditionally with histology although scintigraphic imaging with radiolabeled serum amyloid P component (SAP) has lately been developed as a specific noninvasive alternative. We report a detailed analysis of the abnormal turnover of SAP in patients with systemic amyloidosis and an assessment of its clinical value. METHODS: Iodine-123-labeled human SAP (200 MBq) SAP was injected intravenously into 49 patients with histologically proven systemic AA- or AL- amyloidosis and in 7 control subjects. Plasma clearance and whole-body retention of labeled SAP were analyzed over 48 hr using plasma sampling, whole-body gamma camera imaging and measurement of radioactivity in the urine. The rate of SAP synthesis and interstitial exchange were determined, and the size of the amyloid compartment was compared with clinical estimates of whole-body amyloid load and patient survival. RESULTS: All plasma time-activity curves were biphasic. In comparison with control subjects, patients with amyloidosis showed significantly faster plasma disappearance [4-hr value: AA 48% +/- 18%, AL 45% +/- 15% versus 65% +/- 8% (p < 0.05)], higher total-body retention 48 hr p.i. [AA 74% +/- 14%, AL 73% +/- 17% versus 46% +/- 15% (p < 0.01)] and especially higher extravascular retention 48 hr p.i. [AA 59% +/- 16%, AL 58% +/- 19% versus 30% +/- 14% (p < 0.01)]. Extravascular retention correlated with clinical estimation of the amyloid load. If extravascular retention values in patients with AL amyloidosis were over 60%, survival was decreased (median 4 versus 23 mo, p < 0.001). Markedly increased interstitial exchange rates were present in amyloidosis (AA 64 +/- 61, AL 50 +/- 37 versus 18 +/- 8 mg/hr), whereas the SAP synthesis rate did not differ from the control values (AA 5.0 +/- 3.0, AL 5.5 +/- 3.2 versus 4.5 +/- 1.4 mg/hr). CONCLUSION: The presence of systemic amyloidosis is characterized by accelerated initial clearance of 123I-SAP from the plasma and increased interstitial exchange rate and extravascular retention. These findings reflect reversible binding of radiolabeled SAP to amyloid deposits and provide clinically useful information for diagnosis, monitoring of therapy and prognosis in patients with systemic amyloidosis.     

Familial amyloidotic polyneuropathy type I with extracellular superoxide dismutase mutation: a case report

We report an autopsy case of familial amyloidotic polyneuropathy (FAP) Type I with mutations in both transthyretin (TTR) and extracellular superoxide dismutase (EC-SOD). This patient started to develop peripheral neuropathy at age 25, followed by cardiac, renal, and autonomic nervous system failure due to massive amyloid deposition. Thirteen years after the initial symptoms, he died of septic shock. Autopsy revealed suppurative peritonitis, multiple abscesses in the bile ducts and urinary tract, and more marked amyloid deposition than commonly seen in FAP. Amyloid deposition occurred in various organs and tissues, especially prominently around blood vessels and in interstitial tissues, and was demonstrated immunohistochemically to be composed of TTR but not amyloid A (AA) and not amyloid L (AL) proteins. The serum EC-SOD content of the patient was 10 fold higher than those seen often in other FAP patients and in healthy controls. Genetic analysis demonstrated the single amino acid substitutions in Val30Met TIR and Arg213Gly EC-SOD. Since these data suggest the dissociation of EC-SOD from the vascular wall, massive amyloid deposition in the present case may be related to increased oxidative stress in loco.     

Diagnostic criteria of limited adenocarcinoma of the prostate on needle biopsy

Dialysis amyloidosis is one of the most incapacitating complications of long-term dialysis treatment. Quantitative assessment of amyloid deposition using radiolabelled tracers has been recently proposed but convincing evidence of its validity in uraemic patients remains to be provided. We studied the plasma kinetics of i.v. administered 125I-labelled serum amyloid P component (125I-SAP) in 20 chronic haemodialysis patients compared with those of nine healthy volunteers and three non-dialysed patients with systemic amyloidosis. Plasma clearance of the tracer was abnormal in 17 of 20 dialysis patients in whom plasma radioactivity declined in a bi-exponential mode, in contrast to the single-exponential slope observed in all healthy controls. 125I-SAP plasma half-life of the second component, probably reflecting metabolic clearance, was significantly prolonged in these dialysis patients compared with the healthy controls (35.3 versus 24.6 h, P < 0.001). Among the long-term haemodialysis patients the calculated extravascular distribution of 125I-SAP was significantly greater in those with severe arthropathy than in asymptomatic patients. These findings demonstrate for the first time that SAP clearance is disturbed in haemodialysis patients due to both failing renal elimination and retention in extravascular sites. The extravascular diffusion is greatly enhanced in patients with clinical evidence of amyloidosis. Therefore the study of plasma 125I-SAP kinetics promises to be a valuable tool to quantitate the extent of amyloidosis.     

Discovering transthyretin amyloid fibril inhibitors by limited screening

Insoluble protein fibrils, resulting from the self-assembly of a conformational intermediate are implicated to be the causative agent in several human amyloid diseases including familial amyloid polyneuropathy (FAP) and senile systemic amyloidosis (SSA). These diseases are associated with transthyretin (TTR) amyloid fibrils, which appear to form in the acidic partial denaturing environment of a lysosome or endosome. Here we identify several structural classes of small molecules that are capable of inhibiting the TTR conformational changes facilitating amyloid fibril formation. A small molecule inhibitor that stabilizes the normal conformation of a protein is desirable as a promising approach to treat amyloid diseases and to rigorously test the amyloid hypothesis, the apparent causative role of amyloid fibrils in amyloid disease.     

Liver transplantation in familial amyloid polyneuropathy. Case report and review of the literature

A 59-year old male of German origin noticed exercise-independent cardiac arrhythmia two years before admission. An alanine 47 transthyretin variant of Familial Amyloid Polyneuropathy with hypertrophic cardiomyopathy, peripheral sensory-motor polyneuropathy, I, degree AV heart block was diagnosed. To diminish production and deposition of mutant transthyretin and to prevent disease progression orthotopic liver transplantation was performed. Prior to transplant the patient complained of inappetence. Postoperatively, he received a chemically defined enteral nutrition regime that was discontinued after 30 months until return of appetite and weight gain indicated marked improvement. However, a duodenal biopsy still demonstrated amyloid deposits 24 months after transplantation. Echocardiographic findings remained unchanged. Neurologic examination showed an improvement of sensory-motor polyneuropathy with regression of electromyographic changes. Only traces of variant transthyretin were detectable in plasma samples taken 12 months after the operation. During the 3 year follow-up, no additional symptoms have occurred and progression of amyloidosis was prevented. Currently, orthotopic liver transplantation is the only specific treatment to prevent progression of familial amyloid polyneuropathy.     

Characterization of the transthyretin acid denaturation pathways by analytical ultracentrifugation: implications for wild-type, V30M, and L55P amyloid fibril formation

Analytical ultracentrifugation methods were utilized to further characterize the acid denaturation pathways of wild-type, V30M, and L55P transthyretin (TTR) that generate intermediates leading to amyloid fibril formation and possibly the diseases senile systemic amyloidosis and familial amyloid polyneuropathy. Equilibrium and velocity methods were employed herein to characterize the TTR quaternary structural requirements for amyloid fibril formation. From neutral to slightly acidic conditions (pH 7.5-5.1), wild-type transthyretin (0.2-0.3 mg/mL, 100 mM KCl, 37 degrees C) exists as a tetramer and is incapable of fibril formation. Under more acidic conditions (pH 5 to 3.9), tetrameric wild-type TTR slowly dissociates to a monomer having an alternatively folded tertiary structure(s) that self-assembles at physiological concentration (0.2 mg/mL) into a ladder of quaternary structural intermediates of increasing molecular weight. These intermediates appear to be on the pathway of amyloid fibril formation, since they ultimately disappear when amyloid fibrils are observed. The V30M and L55P TTR variants exhibit similar acid denaturation pathways, with the exception that dissociation of the tetramer to the monomeric amyloidogenic intermediate occurs at a higher pH and to a much greater extent, allowing the quaternary structural intermediates to be readily observed by velocity methods. Partial denaturation and assembly of the monomeric amyloidogenic intermediate(s) occur at pH 5.4 for V30M and L55P TTR over a 72 h period, during which wild-type TTR maintains its normal tetrameric three-dimensional structure. Interestingly, the L55P and V30M familial amyloid polyneuropathy (FAP) associated variants form amyloid protofilaments at pH 7.5 (37 degrees C) after several weeks of incubation, suggesting that the activation barriers for TTR tetramer dissociation to the monomeric amyloidogenic intermediate are much lower for the FAP variants relative to wild-type TTR, which does not form amyloid or amyloid protofilaments under these conditions. This study establishes the key role of the monomeric amyloidogenic intermediate and its self-assembly into a ladder of quaternary structural intermediates for the formation of wild-type, V30M, and L55P transthyretin amyloid fibrils.     

Reduction of voltage-dependent currents by ethanol contributes to inhibition of NMDA receptor-mediated excitatory synaptic transmission

BACKGROUND/AIMS: Primary graft dysfunction is difficult to predict. We have previously shown that indocyanine green clearance measured at 24 h following orthotopic liver transplantation predicts graft survival and outcome. We prospectively evaluated the use of indocyanine green clearance (with a cut-off value of 200 ml/min) as a marker of graft function following orthotopic liver transplantation and investigated its relationship with the markers of reperfusion injury during orthotopic liver transplantation. METHODS: In all patients indocyanine green clearance was measured at 24 h. Repeated blood samples were taken before, during the anhepatic and reperfusion phase and up to 12 h following orthotopic liver transplantation to measure the levels of neutrophil elastase and reactive oxygen intermediates. All patients studied had normal hepatic arterial pulse on Doppler-ultrasound post orthotopic liver transplantation. RESULTS: All patients with indocyanine green clearance >200 ml/min recovered following orthotopic liver transplantation and remained well up to 3 months of follow up. Four patients had an indocyanine green clearance <200 ml/min; three were re-transplanted for graft failure within 3 days of the transplant, while one survived after prolonged intensive support and hospitalization. Indocyanine green clearance significantly correlated with reactive oxygen intermediates production and neutrophil elastase during orthotopic liver transplantation (r=-0.61, p<0.002 and r=-0.66, p<0.0009, respectively). Indocyanine green clearance was also significantly correlated with alanine aminotransferase and prothrombin time at 24 h post-transplantation (r=-0.35, p<0.02 and r=-0.4, p<0.0077, respectively). CONCLUSION: Indocyanine green reflects the degree of reperfusion injury and is a good early marker of primary graft function. Indocyanine green clearance over 200 ml/min is associated with favorable outcome.     

Serum amyloid P component prevents proteolysis of the amyloid fibrils of Alzheimer disease and systemic amyloidosis

Extracellular deposition of amyloid fibrils is responsible for the pathology in the systemic amyloidoses and probably also in Alzheimer disease [Haass, C. & Selkoe, D. J. (1993) Cell 75, 1039-1042] and type II diabetes mellitus [Lorenzo, A., Razzaboni, B., Weir, G. C. & Yankner, B. A. (1994) Nature (London) 368, 756-760]. The fibrils themselves are relatively resistant to proteolysis in vitro but amyloid deposits do regress in vivo, usually with clinical benefit, if new amyloid fibril formation can be halted. Serum amyloid P component (SAP) binds to all types of amyloid fibrils and is a universal constituent of amyloid deposits, including the plaques, amorphous amyloid beta protein deposits and neurofibrillary tangles of Alzheimer disease [Coria, F., Castano, E., Prelli, F., Larrondo-Lillo, M., van Duinen, S., Shelanski, M. L. & Frangione, B. (1988) Lab. Invest. 58, 454-458; Duong, T., Pommier, E. C. & Scheibel, A. B. (1989) Acta Neuropathol. 78, 429-437]. Here we show that SAP prevents proteolysis of the amyloid fibrils of Alzheimer disease, of systemic amyloid A amyloidosis and of systemic monoclonal light chain amyloidosis and may thereby contribute to their persistence in vivo. SAP is not an enzyme inhibitor and is protective only when bound to the fibrils. Interference with binding of SAP to amyloid fibrils in vivo is thus an attractive therapeutic objective, achievement of which should promote regression of the deposits.     

Synchrotron X-ray studies suggest that the core of the transthyretin amyloid fibril is a continuous beta-sheet helix

BACKGROUND: Amyloid diseases, which include Alzheimer's disease and the transmissible spongiform encephalopathies, are characterized by the extracellular deposition of abnormal protein fibrils derived from soluble precursor proteins. Although different precursors seem to generate similar fibrils, no adequate molecular structure of amyloid fibrils has been produced using modern techniques. Knowledge of the fibril structure is essential to understanding the molecular mechanism of amyloid formation and could lead to the development of agents to inhibit or reverse the process. RESULTS: The structure of amyloid fibrils from patients with familial amyloidotic polyneuropathy (FAP), which are derived from transthyretin (TTR) variants, has been investigated by fibre diffraction methods using synchrotron radiation. For the first time a significant high-angle diffraction pattern has been observed showing meridional reflections out to 2 A resolution. This pattern was fully consistent with the previously reported cross-beta structure for the fibril, but also reveals a new large scale fibre repeat of 115 A. We interpret this pattern as that of a repeating unit of 24 beta strands, which form a complete helical turn of beta sheet about an axis parallel to the fibre axis. This structure has not been observed previously. We have built a model of the protofilament of the FAP amyloid fibril based on this interpretation, composed of four beta sheets related by a single helix axis coincident with the fibre axis, and shown that it is consistent with the observed X-ray data. CONCLUSIONS: This work suggests that amyloid fibrils have a novel molecular structure consisting of beta sheets extended in regular helical twists along the length of the fibre. This implies that the polypeptide chains in the fibres are hydrogen-bonded together along the entire length of the fibres, thereby accounting for their great stability. The proposed structure of the FAP fibril requires a TTR building block that is structurally different from the native tetramer. This is likely to be either a monomer or dimer with reorganized or truncated beta sheets, suggesting that amyloid formation may require significant structural change in precursor proteins.     

Heterogeneity of prejunctional neuropeptide Y receptors inhibiting noradrenaline overflow in the portal vein of freely moving rats

Patients with familial amyloidotic polyneuropathy (FAP) showed extremely low plasma apolipoprotein AII (apoAII) levels and apolipoprotein AII/AI (apoAII/AI) ratio while plasma levels of AI, B, CII, CIII, and E were all within normal ranges. To elucidate the reason for these phenomena, we investigated the percent of these proteins contained in high density lipoprotein (HDL) extracted from plasma of FAP patients by ultracentrifugation. The apoAII/AI ratio in extracted HDL was much lower in asymptomatic carriers of FAP as well as FAP patients than that in control subjects. Since a significant amount of apoAII as well as apoAI was recognized in the fraction of the density > 1.21 g/ml in the samples from asymptomatic carriers of FAP and FAP patients, decreased apoAII/AI ratio may result from the increased dissociation of apoAII from HDL during the process of the ultracentrifugation. Electrophoresis of HDL extracted by agarose gel revealed that HDL from asymptomatic carriers of FAP as well as FAP patients increased negative charge, suggesting that nature of HDL itself may change in these subjects. Although urinary excretion of apoAII was increased in carriers of FAP and FAP patients, there was no correlation between plasma and urinary apoAII levels and also no relationship between urinary total protein and apoAII levels. These results suggest that changed affinity of apoAII to HDL may cause the increased secretion of apoAII to the urine and the decreased plasma apoAII level in carriers of FAP and FAP patients.     

Localized amyloidosis in squamous cell carcinoma of uterine cervix: electron microscopic features of nodular and star-like amyloid deposits

An ultrastructural study of amyloid deposits in four cases of squamous cell carcinoma of uterine cervix was performed. The amyloid deposits reacted with anti-keratin antiserum on frozen sections. Amyloid deposits showed nodular (4 cases) and star-like forms (3 cases). Nodular amyloid deposits were composed of slightly whorled fibrils, measuring 7-10 nm in width. Some of them contained cellular debris and thicker, more electron-dense filaments than amyloid fibrils. In three cases, filamentous tumour cells and filamentous masses were observed together with amyloid. Star-like amyloid deposits were composed of bundles of straight amyloid fibrils. Some of the tumour cells in contact with star-like amyloid deposits had deep cytoplasmic invaginations, where closely packed amyloid fibrils were arrayed in parallel fashion. In addition, a few tumour cells had membrane-bound amyloid fibrils in the cytoplasm. It is suggested that nodular amyloid deposits are derived from the tumour cells through filamentous degeneration. Amyloid fibrils in star-like amyloid deposits are thought to be formed within the cytoplasm or in the vicinity of invaginated cytoplasmic membranes of the tumour cells.     

Inhibiting transthyretin conformational changes that lead to amyloid fibril formation

Insoluble protein fibrils resulting from the self-assembly of a conformational intermediate are implicated as the causative agent in several severe human amyloid diseases, including Alzheimer's disease, familial amyloid polyneuropathy, and senile systemic amyloidosis. The latter two diseases are associated with transthyretin (TTR) amyloid fibrils, which appear to form in the acidic partial denaturing environment of the lysosome. Here we demonstrate that flufenamic acid (Flu) inhibits the conformational changes of TTR associated with amyloid fibril formation. The crystal structure of TTR complexed with Flu demonstrates that Flu mediates intersubunit hydrophobic interactions and intersubunit hydrogen bonds that stabilize the normal tetrameric fold of TTR. A small-molecule inhibitor that stabilizes the normal conformation of a protein is desirable as a possible approach to treat amyloid diseases. Molecules such as Flu also provide the means to rigorously test the amyloid hypothesis, i.e., the apparent causative role of amyloid fibrils in amyloid disease.     

Systemic distribution of beta 2-microglobulin-derived amyloidosis in patients who undergo long-term hemodialysis. Report of seven cases and review of the literature

A search for visceral amyloid deposits was performed on autopsy material from 20 patients who had been receiving long-term hemodialysis treatment for 4 to 21 years. Visceral amyloid was found in seven patients who had undergone hemodialysis for more than 10 years. Histochemically, the amyloid was permanganate sensitive, and immunohistochemically, it stained positively for beta 2-microglobulin. The amyloid was found mainly in the wall of blood vessels, in the form of subendothelial nodules, bulging into the vessel's lumen. The amount of amyloid increased with increasing years of hemodialysis treatment. The organs most frequently involved were the heart, gastrointestinal tract, and lungs. Smaller deposits were seen in medium blood vessels of all other visceral organs. Only the spleen was "resistant" to amyloid deposition; the reason for this splenic resistance is unknown. A similar organ distribution was found in the 19 previously reported autopsy cases. Clinically, one patient experienced a perforation of the small intestine, probably related to the narrowing of the intestinal blood vessels by amyloid deposits, and this patient died of peritonitis.     

A clinical, echocardiographic and genetic characterization of a Danish kindred with familial amyloid transthyretin methionine 111 linked cardiomyopathy

AIMS: To identify carriers and non-carriers of the mutant transthyretin methionine 111 linked familial amyloid disease, to detect early signs of the restrictive cardiomyopathy and other clinical manifestations characteristic of this inheritable disease. METHODS AND RESULTS: Out of 125 living family members 99 were available for clinical, echocardiographic and genetic examination. Twenty-five family members were heterozygous carriers of the mutant transthyretin methionine 111 genotype, while 74 were non-carriers. Among the 25 carriers, none had overt clinical signs of heart disease. Eight carriers, all above the age of 35, showed echocardiographic abnormalities suggestive of developing or manifest restrictive cardiomyopathy. Three had biopsy-verified transthyretin-related amyloid cardiomyopathy. None of the 15 carriers in the younger age group exhibited aberrant echocardiographic patterns. Nine carriers had carpal tunnel syndrome as opposed to none of the non-carriers. CONCLUSION: For early detection of familial amyloid cardiomyopathy, echocardiography is the investigation of choice. The first sign is diastolic dysfunction detected as an abnormal relaxation pattern. The appearance of echocardiographic aberrations solely in the older age group suggests that the cardiomyopathy is a late onset disease. Carpal tunnel syndrome appears to be the earliest presenting clinical symptom. A curative treatment seems to be an early liver transplantation.     

Congo red inhibits proteoglycan and serum amyloid P binding to amyloid beta fibrils

Various data suggest that Alzheimer's disease results from the accumulation of amyloid beta (A beta) peptide fibrils and the consequent formation of senile plaques in the cognitive regions of the brain. One approach to lowering senile plaque burden in Alzheimer's disease brain is to identify compounds that will increase the degradation of existing amyloid fibrils. Previous studies have shown that proteoglycans and serum amyloid P (SAP), molecules that localize to senile plaques, bind to A beta fibrils and protect the amyloid peptide from proteolytic breakdown. Therefore, molecules that prevent the binding of SAP and/or proteoglycans to fibrillar A beta might increase plaque degradation and prove useful in the treatment of Alzheimer's disease. The nature of SAP and proteoglycan binding to A beta is defined further in the present study. SAP binds to both fibrillar and nonfibrillar forms of A beta. However, only the former is rendered resistant to proteolysis after SAP association. It is interesting that both SAP and proteoglycan binding to A beta fibrils can be inhibited by glycosaminoglycans and Congo red. Unexpectedly, Congo red protects fibrillar A beta from breakdown, suggesting that this compound and other structurally related molecules are unlikely to be suitable for use in the treatment of Alzheimer's disease.