Partial amino acid sequence homology between an heredofamilial amyloid protein and human plasma prealbumin

Amyloid seeding of transthyretin by ex vivo cardiac fibrils and its inhibition

Each of the 30 human amyloid diseases is associated with the aggregation of a particular precursor protein into amyloid fibrils. In transthyretin amyloidosis (ATTR), mutant or wild-type forms of the serum carrier protein transthyretin (TTR), synthesized and secreted by the liver, convert to amyloid fibrils deposited in the heart and other organs. The current standard of care for hereditary ATTR is liver transplantation, which replaces the mutant TTR gene with the wild-type gene. However, the procedure is often followed by cardiac deposition of wild-type TTR secreted by the new liver. Here we find that amyloid fibrils extracted from autopsied and explanted hearts of ATTR patients robustly seed wild-type TTR into amyloid fibrils in vitro. Cardiac-derived ATTR seeds can accelerate fibril formation of wild-type and monomeric TTR at acidic pH and under physiological conditions, respectively. We show that this seeding is inhibited by peptides designed to complement structures of TTR fibrils. These inhibitors cap fibril growth, suggesting an approach for halting progression of ATTR.

Ostertag revisited: the inherited systemic amyloidoses without neuropathy

Mutations in a number of plasma proteins, including transthyretin, apolipoprotein AI, fibrinogen Aalpha-chain, lysozyme, and apolipoprotein AII, are associated with hereditary systemic amyloidosis. Transthyretin amyloidosis is the most common and is usually associated with peripheral neuropathy. Mutations in the other proteins usually have no neuropathic consequences and, instead, cause principally renal and cardiac amyloidosis. Only the apolipoprotein AI glycine 26 arginine mutation may cause peripheral neuropathy and then in only some of the kindreds with this disease. This review is concerned with the non-neuropathic hereditary systemic amyloidoses. It strives to present a synopsis of the present day knowledge of these diseases including each feature of each precursor protein and its mutations; the clinical phenotype of the disease; and suggestions for treatment when feasible. The main objective is to increase awareness of these autosomal dominant diseases, enhance the chances of early diagnosis, enhance the physician's and subsequently the patient's knowledge of each disease, and finally emphasize the need for more research to find ways to treat or prevent these diseases.

Management of paraproteinemic renal disease

PURPOSE OF REVIEW

Paraproteinemic renal diseases comprise a group of renal disorders that are difficult to manage, in part because of subtleties in the clinical presentation and confusion regarding diagnosis and appropriate therapy. Often, nephrologists make the diagnosis of the underlying plasma cell dyscrasia following renal biopsy. This review seeks to provide a greater understanding of the mechanism of disease and recent approaches to the management of patients who have AL-amyloidosis, monoclonal light-chain and light and heavy-chain deposition disease [termed ML(H)CDD], and cast nephropathy. All three renal lesions are caused by deposition of immunoglobulin light chains. This review seeks to provide a greater understanding of the mechanism of disease and recent approaches to the management of these patients.

RECENT FINDINGS

The immunoglobulin light chain takes the center stage in the pathogenesis of AL-amyloidosis, ML(H)CDD and cast nephropathy. Modifications in the variable domain are responsible for the affinity of the light chain for a given segment of the nephron and the subsequent toxic manifestations. Therapy aimed at eradicating the offending clone of plasma cells that secrete the monoclonal light chain should be beneficial, but this hypothesis lacks confirmation. Four nonrandomized studies have now demonstrated clinical benefit, including return of renal function, of high-dose chemotherapy with autologous stem cell transplantation (HDT/SCT) in the treatment of patients who have AL-amyloidosis or ML(H)CDD.

SUMMARY

While randomized trials are lacking, the data support the clinical efficacy of more aggressive treatments designed to reduce the plasma cell clone responsible for these renal disorders.

AL-amyloidosis is underdiagnosed in renal biopsies

BACKGROUND

Renal amyloidosis is associated with a variety of underlying disease processes. Although amyloid is identical in appearance in these diseases, the precursor proteins are different. Immunofluorescence microscopy has been used as the primary tool in the diagnostic evaluation of the underlying cause of renal AL-amyloidosis. The purpose of this study was to document the sensitivity of immunofluorescence microscopy in AL-amyloidosis.

METHODS

We reviewed 36 renal biopsies from patients with amyloidosis collected in two medical centres. All biopsies showed characteristic fibrillary deposits of amyloid on electron microscopy and stained positive with Congo red or Thioflavin-T.

RESULTS

Among these 36 patients, immunofluorescence staining for lambda and kappa light chains was negative or equivocal in 14 biopsies. Of these 14 patients, two patients had evidence of AA-amyloidosis. Twelve patients were found subsequently to have a plasma cell dyscrasia or multiple myeloma with monoclonal immunoglobulin and/or free light chains on immunofixation electrophoresis of urine or serum, and with evaluation of the bone marrow. Thus, 12 of 34 patients (35.3%) with proven AL-amyloidosis had negative immunofluorescence staining for kappa and lambda light chains.

CONCLUSIONS

The data demonstrated the low sensitivity of immunofluorescence microscopy in the detection of AL-amyloidosis in the kidney and underscore the need to pursue additional diagnostic studies to identify this problem.

Vitreous amyloidosis in familial amyloidotic polyneuropathy. Report of a case with the Val30Met transthyretin mutation

We present a clinical pathological review of vitreous amyloidosis in a case of familial amyloidotic polyneuropathy, type I. Vitreous opacification was the first manifestation of disease in the proband, who was successfully treated with vitrectomy. The eyes were obtained at autopsy after the patient died from an unrelated cause, and the histopathology is presented here. Analysis of DNA from the pathology specimen revealed the most commonly reported transthyretin mutation, Val30Met. The classification of systemic and ocular amyloidosis as well as the genetics of familial amyloidotic polyneuropathy are briefly reviewed.

Hereditary renal amyloidosis associated with a mutant fibrinogen alpha-chain

Three members of a family who died with renal amyloidosis were found to share a single nucleotide substitution in the fibrinogen alpha-chain gene. The predicted arginine to leucine mutation (Arg554Leu) was proven by amino acid sequence analysis of amyloid fibril protein isolated from postmortem kidney of an affected individual. Direct genomic DNA sequencing and restriction fragment length polymorphism analysis demonstrated that all three affected individuals had the guanine to thymine 4993 transversion. This is the first demonstration of hereditary amyloidosis associated with a variant fibrinogen alpha-chain. Variants of circulating fibrinogen may be the cause of a number of systemic amyloidoses with primarily renal involvement.

Gelsolin-related amyloidosis. Identification of the amyloid protein in Finnish hereditary amyloidosis as a fragment of variant gelsolin

The Finnish type of familial amyloidosis is a systemic disease characterized by progressive cranial neuropathy, corneal lattice dystrophy, and distal sensimotor neuropathy. Amyloid fibrils were isolated from the kidney and heart of a patient with Finnish amyloidosis. After solubilization, the amyloid proteins were fractionated by gel filtration and purified by reverse-phase HPLC. Complete amino acid sequence analyses show that the two amyloid components obtained are fragments of gelsolin, an actin-modulating protein occurring in plasma and the cytoskeleton. The larger component represents residues 173-243 and the minor component residues 173-225, respectively, of mature gelsolin. When compared with the predicted primary structure of human gelsolin a single amino acid substitution is present in amyloid: at position 15 of the amyloid proteins an asparagine is found instead of an aspartic acid residue at the corresponding position (187) in gelsolin. Antibodies to a dodecapeptide of the amyloidogenic region of gelsolin specifically stain the tissue amyloid deposits in Finnish hereditary amyloidosis. The results show that the amyloid subunit protein in Finnish hereditary amyloidosis represents a new type of amyloid that is derived from an actin filament-binding region of a variant gelsolin molecule by limited proteolysis.

Spontaneous amyloidosis in mice with malignant neoplasms

An outbred strain of Swiss mice carrying malignant neoplasms (48 female with mammary carcinoma, 1 male with osteosarcoma) is described with a high frequency of amyloid deposits selectively located in the ileum. Amyloid deposits were demonstrated by Congo red staining and electron microscopy. Comments are directed toward methods of amyloid detection, as well as pathogenic considerations.

Amyloidosis of the nervous system

Various types of amyloid fibril deposits occur in the nervous system with unique clinical characteristics and pathogeneses. Genetic mutations cause the familial amyloidotic polyneuropathies and acquired polyneuropathies occurring particularly in patients suffering from hypernephromas and myelomas also result from the production of abnormal proteins. Amyloid fibril deposits in cerebral plaques and vessels consisting of beta-protein are seen in acquired and familial Alzheimer's disease and in Down's syndrome individuals over 40 years of age. This amyloid fibril deposition could result from a mutational, transcriptional or post-translational alteration in these pathologic processes with most evidence supporting the latter. Other diseases including hereditary cerebral hemorrhage of the Dutch type and Batten's disease involve beta-amyloid deposition. The features of the familial and transmissible forms of the spongiform encephalopathies are associated with the prion protein which comprises the amyloid fibril deposits in these conditions. This wide variety of nervous system disorders having amyloid deposits as their primary or subsidiary characteristic make studies of these conditions intriguing models for research workers in clinical, pathologic and molecular biologic fields.

The pathogenesis of reactive systemic amyloidosis

The diagnosis of amyloidosis is based on the presence of extracellular tissue deposits of proteinaceous material that demonstrate a characteristic green color when stained with Congo red and viewed under polarized light. Several different proteins are amyloidogenic but, in domestic animals, spontaneously occurring systemic amyloidosis is reactive in nature and characterized by the presence of amyloid protein AA. This type of systemic amyloidosis may occur secondary to chronic inflammatory or neoplastic disease, but in many instances no predisposing disease is found. A sustained increase in the serum concentration of serum amyloid A protein (SAA) is necessary but not sufficient for the development of reactive amyloidosis. Other inherited and acquired host-related factors are likely to be important in the development of reactive amyloidosis because this condition develops in few patients with chronic inflammatory disease. The tissue tropism of amyloid deposits varies with the amyloid protein itself and species affected. The consequences of amyloidosis for the host depend upon the tissues involved and the response of these tissues to the presence of the amyloid deposits. In domestic animals, reactive systemic amyloidosis is nephropathic, leading to end-stage renal disease, and the clinical presentation is that of uremia.

Transthyretin is synthesized in the mammalian eye

Transthyretin (TTR, prealbumin) is a 55 kDa protein which plays an important role in the plasma transport of thyroxine and retinol. Although the liver and choroid plexus are the two major known sites of TTR synthesis, several lines of evidence suggest the possibility of a separate ocular source of TTR. We report the presence of TTR mRNA in rat and bovine eye and of TTR in rat eye. Preliminary immunohistochemical data indicate that the retinal pigment epithelium is a major site of TTR immunoreactivity in the rat. While the functional significance of ocular TTR synthesis is unclear, TTR may be involved in the ocular translocation and processing of retinol. The finding of TTR synthesis in the eye may explain ocular involvement in the familial amyloidotic polyneuropathies.

Vagus nerve and celiac ganglion lesions in generalized amyloidosis. A correlative study of familial amyloid polyneuropathy and AL-amyloidosis

To clarify the cause of gastrointestinal disorders in systemic amyloidosis we made pathologic and morphometric studies of vagus nerves, celiac ganglia, stomach and rectum in three autopsied cases with type 1 familial amyloid polyneuropathy (FAP) and two with nonhereditary generalized amyloidosis (AL-amyloidosis). The gastric and rectal walls in all cases were affected in the same way by amyloid deposition. On the other hand, there was a great difference between the two diseases in the severity of vagus nerve and celiac ganglion lesions: the vagus nerves in FAP showed very extensive endoneurial deposition of amyloid with severe loss of myelinated nerve fibers, but in AL-amyloidosis there was no loss of myelinated nerve fibers and only slight amyloid deposition in the endoneurium. Similarly, in the celiac ganglion, intraganglionic deposition of amyloid was prominent in FAP and slight in AL-amyloidosis. It is known that bowel symptoms frequently occur in type I FAP and are less prominent in AL-amyloidosis. This study demonstrated that the gastrointestinal autonomic nerves were more markedly disturbed by amyloid in the former than in the latter, and disorder in neural control of the digestive tract may be responsible for the bowel symptoms in systemic amyloidosis, especially in type I FAP.

Onset in the seventh decade and lack of symptoms in heterozygotes for the TTRMet30 mutation in hereditary amyloid neuropathy-type I (Portuguese, Andrade)

In a Portuguese-American family with hereditary amyloid neuropathy (familial amyloidotic polyneuropathy), onset was in the seventh decade in all affected relatives. Another unusual characteristic was their origin from the Portuguese island of Madeira. In spite of this, the mutant transthyretin (TTRMet30) (the same variant prealbumin that is the circulating precursor of AFP protein in the classic Portuguese patients) could be found in the propositus' plasma. In addition, three other asymptomatic relatives (ages 90, 73, and 48) were shown to carry the mutation. Late onset and incomplete penetrance, at a clinical level, raise problems for presymptomatic detection of mutant TTR, as these tend to cluster in families. When counseling asymptomatic heterozygotes, we must consider intra-familial correlation in age-of-onset, and the distribution of age-of-onset including age of unaffected heterozygotes. This family poses interesting questions regarding pathogenesis of this degenerative process and the influence of other genetic factors, such as modifiers, epistasis, and polymorphism of the TTR genes or their regulators. A cis-effect of a gene linked to the mutant gene, decreasing the synthesis of the mutant TTR and keeping a sufficient amount of the normal one in circulation, or producing some cofactor for TTR, could also explain late onset and apparently incomplete penetrance; the occasional finding of classic forms in these families would be the result of recombinatory events.

Pars plana vitrectomy for vitreous amyloidosis

Thirty-six pars plana vitrectomies were performed on 30 eyes of 17 patients with biopsy-proven vitreous amyloidosis. Reopacification of the retrolental vitreous was the most common reason for vitrectomy revision, required in 24% of patients. Complications of amyloid or vitrectomy included retinal detachment requiring scleral buckling in 17% of eyes and glaucoma requiring filtering surgery in 17% of eyes. After a mean 35-month post-vitrectomy follow-up, 48% of eyes had visual acuities of 20/40 or better, and 32% of eyes had visual acuities between 20/50 and 20/100. Twenty percent of eyes had visual acuities of 20/200 or worse due either to persistent retinal detachment, open angle glaucoma, or residual opacification of the vitreous.

Prealbumin: its association with amyloid

In recent years prealbumin has been shown to be a major component of two forms of systemic amyloid, senile systemic amyloid (SSA), and familial amyloidotic polyneuropathy (FAP). Despite the fact that the amyloid fibril proteins associated with these two forms of amyloid, designated ASc1 and AF, respectively, share many similarities the clinical features of the two diseases are remarkably different. To understand better this paradox the clinical, histochemical, immunological and biochemical features of SSA and FAP were reviewed.

Carpal tunnel syndrome caused by amyloid containing beta 2 microglobulin: a new amyloid and a complication of long term haemodialysis

Three patients receiving long term haemodialysis treatment for chronic renal failure due to non-amyloid nephropathy developed the carpal tunnel syndrome requiring decompression surgery. The excised material contained amyloid, which by immunocytochemical techniques was shown to contain beta 2 microglobulin. This is, therefore, a new chemical form of amyloid whose deposition is likely to be the cause of osteoarticular and connective tissue disorders, which are being recognised with increasing frequency in patients receiving long term haemodialysis. Raised beta 2 microglobulin levels are known to occur in chronic renal failure, and the molecule is unable to cross conventional dialysis membranes. The importance of beta 2 microglobulin amyloidosis lies in the threat which it poses to the success of long term haemodialysis.

Characterization of different amyloids with immunological techniques

We studied 71 cases of amyloidosis from the autopsy material of our institute. 17 cases were secondary amyloidosis of which 7 had initially been diagnosed as primary amyloidosis; all cases reacted positively with an anti-substance A antibody; 13 showed a suppression and 4 a strong reduction of the Congo red staining following tissue incubation in KMnO4. 25 cases were identified as primary amyloidosis of which 7 had initially not been recognized as such. In 16 cases amyloid deposits reacted positively with antibodies specific for the light chains of the immunoglobulins (3 X kappa, 13 X lambda). A monoclonal plasmacytic cell proliferation in the bone marrow was seen in 14 cases. In all cases deposits were KMnO4 resistant, but 1 case showed a slight reduction of staining intensity. 27 cases were cardio-vascular (senile) amyloidosis; in 20 cases at least 3 organs showed deposits; 12 cases had deposits in 5 and more organs. 2 cases were heredofamilial amyloidosis. In those 29 cases deposits reacted positively with an anti-prealbumin antibody, but were negative for AA and the light chains of the immunoglobulins; the Congo red staining remained strong in all cases when previously incubated in KMnO4. KMnO4-Congo red staining and antisera specific for AA, L-chains and prealbumin proved of value for classification of amyloidosis and for its organ distribution.

Characterization of a transthyretin (prealbumin) variant associated with familial amyloidotic polyneuropathy type II (Indiana/Swiss)

Amyloid fibrils were isolated from cardiac tissue of two brothers who died from familial amyloidotic polyneuropathy (FAP) type II. Sequence analysis on peptides derived from proteolytic cleavage with trypsin and fragmentation with cyanogen bromide reveal that the fibril subunit protein is derived from plasma transthyretin (prealbumin). About two-thirds of the fibril subunit protein was found to contain an amino acid substitution at position 84 where the normal isoleucine residue has been replaced by serine. Sequence analysis of the plasma transthyretin (prealbumin) from the two brothers as well as two clinically diagnosed FAP type II family members and two of four children of affected individuals showed the presence of serine at position 84. The presence of this substitution also correlates with low serum levels of retinol-binding protein and thus transthyretin (prealbumin) position 84 may be involved with the interaction of these two proteins.

Biochemical and molecular genetic characterization of a new variant prealbumin associated with hereditary amyloidosis

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant late-onset disorder characterized by the extracellular deposition of amyloid fibrils. In all cases studied these fibrils have been found to be composed of plasma prealbumin (transthyretin) containing a single amino acid substitution. Biochemical studies were conducted on amyloid from one patient and plasma prealbumin from his affected brother, both part of a large kindred from the Appalachian region of the United States. Sequence analysis of the amyloid subunit protein showed it to be prealbumin with about two-thirds of the molecules containing a substitution of alanine for threonine at position 60. Studies of the plasma prealbumin showed that the same substitution was present in 40-45% of the protein. Based on this substitution and the prealbumin cDNA sequence, a Pvu II restriction fragment length DNA polymorphism (RFLP) was predicted and demonstrated in DNA of both patients as well as other family members. This RFLP confirms the predicted DNA mutation responsible for the protein variant, and represents an accurate method for detection of this gene.

Characterization of amyloid deposits in biopsies of 15 with "sporadic" (non-familial or plasma cell dyscrasia amyloid polyneuropathy

Review of the clinical and laboratory findings of 39 patients with amyloid polyneuropathy (AP) showed 12 cases to be hereditary and 12 to be associated with plasma cell dyscrasia (PCD). The remaining 15, termed "sporadic" AP, had neuropathy clinically indistinguishable from the other two groups but without a clinicopathologically identified PCD or positive family history. In an attempt to identify the type of amyloid in "sporadic" AP, the immunoreactivity of amyloid deposits was investigated using specific antisera raised against the following different chemical types of amyloid fibril proteins: variable regions of amyloid light chains kappa (A kappa) and lambda (A lambda), amyloid protein AA, and prealbumin. It was found that the amyloid in "sporadic" AP had A lambda antigenic determinants in ten cases, A kappa in one and prealbumin in three; in one case, the A lambda nature of amyloid was confirmed biochemically on the extracted amyloid fibrills. Thus, the most common type of AP in our population appears to be the "sporadic" form. In "sporadic" AP, the amyloid is most commonly of immunoglobulin light chain origin, even in the absence of overt PCD, and it can be rapidly categorized immunocytochemically to determine therapeutic directions or provide genetic guidance.

Familial amyloid polyneuropathy

Amyloid fibrils were isolated from the myocardium of two patients with familial amyloid polyneuropathy. The solubilized amyloid fibril whole protein shared immunologic determinants with normal human serum prealbumin (transthyretin), but revealed subtle differences on immunoelectrophoresis and radial immunodiffusion. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, amyloid fibril whole protein was resolved into numerous bands that reacted with antitransthyretin on immunoblots. The whole protein also contained peptide fragments of fibronectin, but was devoid of amyloid P protein. An antiserum raised against the whole protein was suitable for immunocytochemistry of amyloid in paraffin sections. In contrast, commercial antitransthyretin, raised against the intact tetrameric protein failed to react with tissue amyloid. Immunochemical and immunocytochemical results support the concept that familial amyloid polyneuropathy with cardiomyopathy is due to infiltration of susceptible tissues by an anomalous transthyretin.

The amyloid in familial amyloid cardiomyopathy of Danish origin is related to pre-albumin

Amyloid obtained from the myocardium of a patient (Han) with familial amyloid cardiomyopathy of Danish origin was studied. Gel filtration and electrophoresis of purified and denatured amyloid fibrils Han revealed various fractions ranging in mol. wt from 40,000 to 8,000 daltons. Amyloid Han and fractions reacted with an antiserum against amyloid Han showing a reaction of identity with each other; partial identity between Han and human pre-albumin was observed, while no reaction was seen with AA or AL proteins. Cardiac tissue sections from Han showed reactivity with antisera to amyloid Han, pre-albumin and protein AP, but not with anti-AA or anti-AL in indirect immunofluorescence. Amino acid composition and sequence studies of a protein fraction of amyloid Han with mol. wt 15,000 daltons confirmed the structural relationship with pre-albumin.

Prealbumin in Swedish patients with senile systemic amyloidosis and familial amyloidotic polyneuropathy

A prealbumin (PA)-like protein was demonstrated in amyloid fibrils both from a patient with senile systemic amyloidosis (SSA) and from a patient in northern Sweden with familial amyloidotic polyneuropathy (FAP). The investigated properties of this protein were similar in the two types of fibrils. The protein had molecular weight, antigenic determinants, and at least one cysteinyl residue in common with the subunit of normal PA. In contrast to normal PA, it contained disulphide-linked subunits and was to some extent bound to the fibril via the cysteinyl residues. The noncovalent forces between its subunits were weaker than in normal PA. It constituted part of the previously described AScl protein of the SSA fibrils. Proteins with lower molecular weight than the PA monomer were major proteins in both SSA and FAP fibrils. These proteins had similar properties in the two kinds of fibril and may be derived from PA. PA in serum from Swedish patients with FAP and SSA was normal with regard to the isoelectric pH of the monomers and tetramers.

Lowered prealbumin levels in patients with familial amyloid polyneuropathy (FAP) and their non-affected but at risk relatives

Amyloid fibrils in familial amyloid polyneuropathy, the familial (AF) form of systemic amyloidosis, are composed of the monomeric unit (14,000 MW) of prealbumin molecules. By radioimmunoassay, the serum level of prealbumin was measured in 25 patients from 12 different kinships with this dominantly inherited form of amyloidosis and 56 unaffected, but at risk, relatives from two of the kinships. Results were compared to prealbumin levels in normal individuals and patients with primary (AL) and secondary (AA) forms of systemic amyloidosis. Significantly lowered prealbumin levels were found in the AF patients (149.2 micrograms/ml) and their at risk relatives (169.0 micrograms/ml) when compared to normal individuals (232.9 micrograms/ml), AL patients (221.9 micrograms/ml) and AA patients (211.7 micrograms/ml). No abnormality was found in levels of retinol binding protein (RBP), which is carried by prealbumin, in the serum of either the AF patients or their relatives. The depressed prealbumin levels may indicate a structural variant molecular form, an extra hepatic synthesis or an abnormality in catabolism of this protein that is present prior to the clinical or histopathologic onset of the AF disease.

Identification of carriers of a variant plasma prealbumin (transthyretin) associated with familial amyloidotic polyneuropathy type I

A method is described for detecting carriers of a variant plasma prealbumin that is associated with familial amyloidotic polyneuropathy (FAP) type I. It is based on the finding of an extra methionine in the variant prealbumin, at position 30 from the amino terminals. Since normal prealbumin has only one methionine (position 13), treatment with cyanogen bromide (CNBr), which cleaves only at methionines, results in two peptides. CNBr treatment of the variant prealbumin gives three peptides. The extra can then be detected in two ways: by HPLC using a reverse phase C18 column, and by sequential Edman degradation. Each method can detect as little as 1% variant prealbumin in isolated plasma prealbumin, and therefore, can identify carriers of the gene for the variant protein. Since FAP type I usually is not manifest until after the childbearing years, this method to identify carriers of the gene offers a new approach for genetic counseling of families with this disease. To date, kindreds with hereditary amyloidosis that could benefit from these studies include those with FAP type I of Swedish, Japanese, and Portuguese origins.

Senile systemic amyloidosis

The senile amyloidoses comprise a heterogeneous group of disorders with deposition of amyloid in a variety of tissues. Most of these amyloidoses are localized to one tissue. It has been shown previously that the amyloid fibrils in one form of senile amyloidosis affecting the heart contains a prealbumin-related protein, ASc1. It is shown in this paper by immunohistochemical study using a specific anti-protein ASc1 antiserum that this type of amyloidosis, previously called senile cardiac amyloidosis, is a systemic disease with amyloid deposits in many organs. The designation senile systemic amyloidosis is proposed for this disease, which differs from other systemic amyloidoses in distribution of amyloid deposits.

Family studies of the genetic abnormality in transthyretin (prealbumin) in Portuguese patients with familial amyloidotic polyneuropathy

Amyloid deposits in several heredofamilial forms of amyloidosis are chemically related to transthyretin (TTR, the protein usually referred to as prealbumin). A genetically abnormal TTR may be involved. Studies were conducted on TTR isolated from sera of patients with familial amyloidotic polyneuropathy (FAP), and on amyloid fibril protein (AFp) isolated from tissues of two Portuguese patients who died with FAP. AFp, purified by affinity chromatography on retinol-binding protein (RBP), resembled plasma TTR in forming a stable tetrameric structure, and in its binding affinities for both thyroxine and RBP. Purified AFp was found to comprise a TTR variant with a methionine for valine substitution at position 30. This conclusion was based upon studies that included: (i) comparative peptide mapping by reverse-phase high-performance liquid chromatography after trypsin digestion; (ii) cyanogen bromide (CNBr) cleavage studies; and (iii) amino acid microsequence analysis of selected tryptic and CNBr peptides. The variant TTR was also found to be present in serum samples from FAP patients, along with larger amounts of normal TTR. An effective, small-scale procedure was developed to determine whether or not the variant TTR was present in the plasma of an individual subject. This procedure involved isolation of TTR by affinity chromatography on RBP, followed by CNBr cleavage, and analysis for the presence of specific aberrant CNBr peptides. Studies with six kindreds, including 21 asymptomatic children of 6 patients with FAP, showed that the "abnormal" TTR can be detected and used as a preclinical marker of the disease in affected children of patients with FAP. It is likely that the variant TTR represents a point mutation within the TTR structural gene, and that the normal and mutant genes act as co-dominant alleles at a single locus in FAP. The distribution of the mutant TTR within the six families was consistent with the autosomal dominant mode of inheritance of FAP. The mutant TTR apparently selectively deposits in tissues as the amyloid characteristic of the disease.

Clinical value of immunohistochemistry with AF-antibody in the diagnosis of familial amyloid neuropathy

Peripheral polyneuropathy associated with recurrent diarrhoea and orthostatic hypotension was observed in two unrelated German kinships and two sporadic cases. Congo red staining and polarization microscopy of biopsy specimens revealed amyloid deposits. Immunohistochemical investigation using the indirect immunoperoxidase staining with antisera to several purified amyloid fibril proteins showed a positive reaction with an antiserum to the prealbumin-related AF-amyloid in the families and one of the sporadic cases and with an antiserum to the immunoglobulin light chain amyloid (A lambda) in the other sporadic case. Therefore, the amyloid of the families and one of the sporadic cases was identified as the prealbumin-related AF amyloid, while the amyloid of the other sporadic case was of immunoglobulin origin. It is concluded that immunohistochemistry with antisera to the different amyloid proteins is useful in the differential diagnosis of amyloid neuropathy.

Lack of evidence for protein AA reactivity in amyloid deposits of lattice corneal dystrophy and amyloid corneal degeneration

Amyloid fibrils occurring in primary and myeloma-associated (AL), secondary (AA), and certain neuropathic hereditary forms of systemic amyloidosis can be distinguished biochemically or immunohistologically as being composed of immunoglobulin light chain, protein AA, or prealbumin respectively. All types of systemic and several localized forms of amyloidosis contain amyloid P component (protein AP). We studied formalin-fixed tissue from eight cases of lattice corneal dystrophy by the immunoperoxidase method using antisera to proteins AA and AP, to normal serum prealbumin and prealbumin isolated from a case of hereditary amyloidosis, and to light-chain determinants; additional cases were examined by indirect immunofluorescence of fresh-frozen material. We found weak (1:10 dilution) staining with anti-AP, but no reactivity with other antisera. Congo red staining was resistant to pretreatment of sections with potassium permanganate, a characteristic of non-AA amyloid. Two-dimensional gels of solubilized proteins from frozen tissue from two cases of lattice corneal dystrophy resembled those obtained from normal human cornea. Western blots of two cases of polymorphous amyloid degeneration and solubilized protein from normal cornea did not react with radioactive iodine-labeled anti-AA or anti-AP with purified protein AP and unfixed protein AA amyloid tissue as controls. We were unable to corroborate the presence of protein AA in the amyloid deposits of lattice corneal dystrophy. Although staining with antiserum to protein AP was demonstrable, the molecular configuration of this protein in stromal deposits remains to be defined.

Amyloid fibril protein in familial amyloidotic polyneuropathy, Portuguese type. Definition of molecular abnormality in transthyretin (prealbumin)

Amyloid fibril protein in patients with familial amyloidotic polyneuropathy is known to be chemically related to transthyretin (TTR), the plasma protein that is usually referred to as prealbumin. A genetically abnormal TTR may be involved in this disease. Studies were conducted on amyloid fibril protein (AFp) isolated from tissues of two Portuguese patients who died with familial amyloidosis, and on TTR isolated from sera of patients with this disease. AFp, purified by affinity chromatography on retinol-binding protein linked to Sepharose, resembled plasma TTR in forming a stable tetrameric structure, and in its binding affinities for both thyroxine and retinol-binding protein. The structural studies included: (a) comparative peptide mappings by reverse-phase high performance liquid chromatography (HPLC) after trypsin digestion; (b) cyanogen bromide cleavage studies; and (c) amino acid microsequence analysis of selected tryptic and CNBr peptides. On the basis of the known amino acid sequence of TTR, comparative tryptic peptide maps showed the presence of a single aberrant tryptic peptide (peptide 4, residues 22-34) in AFp as compared with TTR. This aberrant peptide contained a methionine residue, not present in normal tryptic peptide 4. CNBr cleavage of AFp produced two extra peptide fragments, which were demonstrated, respectively, by HPLC analysis and by sodium dodecyl sulfate-gel electrophoresis. Sequence analyses indicated the presence of a methionine-for-valine substitution at position 30 in AFp as compared with TTR. Thus, the purified amyloid fibril protein comprised a TTR variant with a methionine-forvaline substitution at position 30. A single nucleotide change in a possible codon for valine 30 could explain the substitution. The variant TTR was also present in the TTR isolated from the pooled sera of amyloidoses patients, together with larger (four- to six-fold) amounts of the normal TTR. Thus, in these patients, the variant TTR was circulating in plasma, along with larger amounts of normal TTR. We suggest that the variant TTR represents the specific biochemical cause of the disease, and that this abnormal form of TTR selectively deposits in tissues as the amyloid characteristic of the disease.

Immunocytochemical demonstration of prealbumin in the vitreous in heredofamilial amyloidosis

Vitreous material obtained at pars plana vitrectomy from a patient with heredofamilial amyloidosis with vitreous involvement and control vitreous from a patient without amyloidosis were subjected to immunocytochemical studies. P component (AP), a minor constituent of all amyloid deposits, was found in trace amounts in the familial amyloid vitreous, but other amyloid proteins, which occur in secondary amyloidosis or in primary amyloidosis, were not found. The major amyloid protein in the vitreous in heredofamilial amyloidosis (but not control vitreous) was found to be prealbumin.

Primary structure of an amyloid prealbumin and its plasma precursor in a heredofamilial polyneuropathy of Swedish origin

Prealbumin from an individual with heredofamilial amyloid polyneuropathy of Swedish origin was isolated from plasma by using a three-step procedure involving ion exchange, Affi-gel Blue affinity chromatography, and gel filtration. This prealbumin and its associated amyloid fibril subunit protein were digested with trypsin and the resulting peptides were separated by high performance liquid chromatography. Comparison with normal prealbumin peptides showed that an amino acid substitution of a methionine for a valine had occurred at position 30. In the plasma prealbumin, the abnormal residue accounted for 1/3rd of the material while in the amyloid fibrils it accounted for 2/3rds. From this sequence information and the known three-dimensional structure of the prealbumin molecule, a mechanism for the amyloid formation is proposed. It involves formation of the amyloid fibrils by addition of prealbumin dimers or tetramers to the aggregate. Each dimer must contain at least one variant peptide chain while the tetramer must contain at least two abnormal chains. Either of these models can account for the observed amount of normal prealbumin in amyloid fibrils. No proteolytic processing of this molecule is required because the entire undegraded prealbumin molecule is found in the fibrils.

Familial amyloid polyneuropathy. Demonstration of prealbumin in a kinship of German/English ancestry with onset in the seventh decade

A family with autosomal dominant transmitted familial amyloid polyneuropathy residing in Texas is described. Clinically, the prominent sensory and severe autonomic nervous system involvement resembles the Andrade (Portuguese) type I familial amyloid polyneuropathy but is unique in that the age of onset is in the seventh decade in all family members affected to date. Using an immunoperoxidase technique, prealbumin was demonstrated in the amyloid deposits. This finding suggests that this family shares biochemical as well as clinical characteristics consistent with similar kinships with type I familial amyloid polyneuropathy of diverse geographic origin.

Type I familial amyloidotic polyneuropathy (Japanese type)

Our recent studies on familial amyloidotic polyneuropathy (FAP) were reviewed. Since the clinical picture of our FAP is slightly different from those of the Portuguese type, the Swedish type, and the Jewish type, structural identification of the amyloid fibril proteins should be clarified on a molecular basis. Further investigation on the effectiveness of dimethyl sulfoxide (DMSO) or a search for other useful new drugs is greatly required.

Reactive (secondary) amyloidosis and its pathogenesis

Recent advances in amyloid research have broadened our understanding of amyloidogenesis in connection with chronic inflammatory and infectious conditions. Experimental and clinical studies have clarified many of the mechanisms of induction, synthesis and regulation of the amyloid-related serum component SAA and have shed light on the enzymatic processes involved in the cleavage of SAA and degradation of fibrillar AA protein. The current pathogenetic model emphasizes the dynamic character of amyloid disease.

Prealbumin and retinol binding protein serum concentrations in the Indiana type hereditary amyloidosis

Serum prealbumin and retinol binding protein (RBP) concentrations were determined for 68 members of a kindred in Indiana with a familial type of systemic amyloidosis. Immunohistochemical studies on rectal and muscle biopsy material from individuals with this type of amyloidosis revealed staining of amyloid deposits with anti-prealbumin. Both the serum prealbumin and RBP concentrations were significantly depressed in 9 patients with amyloidosis when compared with normal controls and unaffected kin. In addition, the mean RBP serum concentration of 21 offspring of the patients with amyloidosis was significantly depressed. A more significant finding was that on the basis of the serum RBP concentrations, the offspring could be divided into 2 distinct groups. One group represented approximately 50% of the children and had serum prealbumin and RBP concentrations not significantly different from their afflicted parents. The second group had serum prealbumin and RBP concentrations not significantly different from those of normal controls and non-affected kin. These findings show that prealbumin and RBP serum concentrations are depressed in patients with the Indiana type of hereditary amyloidosis and that these serum abnormalities may be present long before development of clinical disease. They suggest that individuals with this genetic abnormality may be identified prior to clinical expression of the disease.

Identification of amyloid prealbumin variant in familial amyloidotic polyneuropathy (Japanese type)

Structural studies on an amyloid fibril protein of 14 K daltons (AFj(INO] isolated from a Japanese patient who suffered from familial amyloidotic polyneuropathy were carried out to unambiguously identify its difference from normal human serum prealbumin. Sequence analyses performed by comparing peptide maps prepared from cyanogen bromide fragments and tryptic peptides of purified RCM-amyloid protein with those from RCM-prealbumin indicate that only a valine residue at position 30 in prealbumin is replaced by a methionine residue. Furthermore, it was also proved that AFj(INO) consists of four components; the prealbumin variant and its three related proteins, which are derived by successively accumulated deletion of the N-terminal three amino acid residues (Gly1, Pro2 and Thr3) from the prealbumin variant.

Frequency and distribution of senile cardiovascular amyloid. A clinicopathologic correlation

Atrium, ventricle, aorta, lung, kidney, and rectum were removed at autopsy from 85 consecutive elderly patients (aged 80 years or older) and examined for amyloid with Congo red. All tissues containing amyloid were counterstained with an antiserum specific for amyloid fibril protein ASc1 and studied by immunofluorescence. Three distinct forms of amyloid were found: (1) all patients had senile aortic amyloid; (2) 78 percent of patients had isolated atrial amyloid; and (3) 25 percent of patients had senile cardiac amyloid of the ASc1 type. The cardiac amyloid deposits were small and widely scattered in more than 80 percent of patients with isolated atrial amyloid and in more than 50 percent of patients with ASc1-type amyloid. Of 21 patients with ASc1 amyloid, 19 had extracardiac involvement (lung in 81 percent of cases and rectum in 57 percent of cases). The kidney was not involved in any patient. The mean heart weight, frequency of atrial fibrillation, percentage of patients with heart failure, and frequency of myocardial infarction were increased in patients with cardiac amyloid, but these differences failed to reach statistical significance. There was no difference in the mean left ventricular wall thickness or degree of coronary atherosclerosis.

Erosive arthritis in hereditary amyloidosis

Nine patients from 2 distinct kindreds with familial amyloidosis had episodes of inflammatory arthritis and radiographic evidence of joint erosions. Histologic features from erosive lesions in both kindreds showed proliferation of synovium with erosive bone and cartilage change. No large amyloid deposits were seen. This study indicates that an erosive synovitis of unknown cause may be a feature of some forms of hereditary amyloidosis.

Polymorphism of human plasma thyroxine binding prealbumin

Amyloid fibrils from an individual with heredofamilial amyloidosis were found to be composed of plasma prealbumin. To study this protein a three step procedure to isolate prealbumin from plasma was developed. It entailed ion exchange chromatography on DEAE Sephadex, affinity chromatography on Affi-gel Blue and gel filtration on AcA-34. Trypsin Digests of prealbumin were separated by reverse phase HPLC and the pattern compared to that from the normal protein. Only one unexpected peptide was found and it represented the substitution of a methionine for a valine at position 30 in the molecule. This substitution accounts for about 1/3 of the isolated molecules and it represents the first point mutation identified in human plasma prealbumin.

Familial amyloid polyneuropathy with marked hypertrophy of the peripheral nerves

Autopsy findings in a 40-year-old male with heredofamilial amyloidosis and polyneuropathy are reported. He had been suffering from progressive autonomic as well as sensorimotor dysfunctions. Prominent amyloid deposit was found in the kidney, heart, thyroid, and testis, and less in the interstitium and small vessels of almost all organs. The peripheral nerves, some showing prominent hypertrophy, were most severely involved by amyloid deposit in a form of stellate mass, which ultrastructurally consisted of radially arranged amyloid filaments. In the hypertrophied nerves and ganglia, in addition to amyloid, massive accumulation of acid mucopolysaccharide (AMPS) was seen filling up the interstitial space, which was the cause of hypertrophy. Ultrastructurally, AMPS was seen as finely granular substance. An extracted amyloid from the kidney showed 8 nm filament on negative staining and was estimated of having a molecular weight of 14,000.

Characterization of amyloid deposits and P component from a patient with factor X deficiency reveals proteins derived from a lambda VI light chain

Amyloid fibrils were isolated from a spleen obtained at surgery from a 58-year-old white man with primary amyloidosis presenting with factor X deficiency and responding dramatically to splenectomy. Gel filtration on Ultragel ACA 54 in 5 M guanidine 1 M acetic acid yielded components with molecular weights between 17,000 and 13,000. Two of them (17K and 15K) were studied in detail. Antigenic and amino acid sequence analysis showed that these proteins were related to lambda VI immunoglobulin light chain. The predominant protein subunits of the amyloid fibril of the deposits (17K) was processed at the carboxy terminus in the same section of the constant region as the only other lambda VI amyloid protein previously reported. Amino terminal sequence of the 15K protein revealed not only degradation at the C terminal, but also minor degradation at the amino terminal (three residues difference from the 17K species). P component was also isolated from the spleen and characterized. This represents the first antigenic and sequence analysis of tissue amyloid proteins and P component from a patient presenting with factor X deficiency and another example of amyloid proteins derived from the newly discovered amyloidogenic lambda VI light chain subgroup.

Immunohistochemical identification of the AA protein in lattice dystrophy

We examined the amyloid deposits of lattice dystrophy type I for common components of primary and secondary amyloid using the sensitive unlabelled antibody peroxidase-antiperoxidase technique. Tissue sections of formalin-fixed, paraffin-embedded specimens from three patients with lattice dystrophy were reacted with antisera specific for free immunoglobulin light chains, prealbumin, amyloid A (AA) protein, and amyloid P (AP) protein. The lattice amyloid was positive for the AA protein associated with secondary amyloid. The deposits were also stained with the protein AP antiserum in each case. We were unable to detect the presence of immunoglobulin light chains associated with primary amyloid or prealbumin associated with another heredofamilial form of amyloid. Sera from two patients with lattice dystrophy were tested for the presence of the serum amyloid A related protein, the apparent precursor of AA amyloid, by immunoelectrophoresis and immunodiffusion. The sera showed no reaction with the AA antiserum with these techniques. Lattice amyloid differed from secondary systemic amyloid in the reaction with potassium permanganate. Congo red staining of lattice deposits was not abolished by treatment with potassium permanganate. Our findings suggest that the amyloid proteins in lattice dystrophy are antigenically similar to those of secondary amyloid and the hereditary form associated with familial Mediterranean fever.

The isolation and amino acid composition of senile plaque core protein

A new method has been developed for the isolation of intact senile (neuritic) plaque cores from post-mortem brains of patients with Alzheimer's disease. The plaque cores were found to be insoluble in various protein denaturants. The amino acid composition of the plaque core protein does not resemble that of any known form of amyloid.

Amyloid of the seminal vesicles. A distinctive and common localized form of senile amyloidosis

Amyloid deposits were found subepithelially in the seminal vesicles of 34 of 209 consecutively studied men. The incidence increased with age and was found in 21% of men over 75 years. This senile seminal vesicle amyloidosis (SSVA) is a localized disorder, and the amyloid substance has unique histochemical and immunochemical properties not shared with any other amyloid described until now.