Misclassification of amyloidosis is unwarranted.
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Amyloid↗
Biomedical subjects
Alan Solomon
Publications and source records attributed to Alan Solomon.
Diagnostic and therapeutic potential of amyloid-reactive IgG antibodies contained in human sera.
Passive immunotherapy using fibril-reactive mAbs has been shown experimentally to reduce amyloid formation and also accelerate amyloidolysis. We now report that human sera, as well as various sources of pooled human IgG, including pharmacologic formulations of immune globulin i.v. (IGIV), contain Abs that specifically recognize fibrils formed from light chains and other amyloidogenic precursor proteins, including serum amyloid A, transthyretin, islet amyloid polypeptide, and amyloid beta 1-40 peptide, but notably, do not react with these molecules in their native nonfibrillar forms. After isolation of the Abs from IGIV via fibril-conjugated affinity column chromatography, the EC50-binding value for light chains and amyloid beta 1-40 peptide fibrils was approximately 15 nM-a magnitude approximately 200 and 70 times less than that of the unbound fraction and unfractionated product, respectively. Comparable reactivity was found in the case of those formed from serum amyloid A, transthyretin, and islet amyloid polypeptide. The purified Abs immunostained human amyloid tissue deposits and could inhibit fibrillogenesis, as shown in fibril formation and extension assays. Most importantly, in vivo reactivity was evidenced in a murine model when the enriched Abs were used to image amyloid, as well as expedite its removal. These promising experimental results suggest that fibril affinity-purified IGIV has potential as a diagnostic and therapeutic agent for patients with amyloid-associated disease.
Amyloid↗
Amyloid contained in the knee joint meniscus is formed from apolipoprotein A-I.
OBJECTIVE: To determine the chemical nature of amyloid deposits found in knee joint menisci. METHODS: Amyloid was extracted from the menisci of 3 adults who underwent knee joint replacement surgery. The primary structural features of the purified proteins were determined by sequential Edman degradation and tandem mass spectrometry (MS/MS). Tissue specimens were also subjected to in situ hybridization analysis, as well as complementary DNA cloning by reverse transcriptase-polymerase chain reaction (RT-PCR). Additionally, specimens from these 3 patients, as well as other patients with amyloid in the knee joint menisci, were examined immunohistochemically. RESULTS: Amino acid sequence and MS/MS analyses of the extracts revealed the presence of 60-77-residue components identical to the N-terminal portion of apolipoprotein A-I (Apo A-I). The Apo A-I nature of the amyloid was confirmed by the demonstration that the green birefringent congophilic deposits in the 7 meniscus samples were recognized by an anti-human Apo A-I antibody. That the meniscus itself was the source of the amyloidogenic protein was evidenced through Southern blot analysis, in which an Apo A-I product was generated by RT-PCR from synovial tissue, and further, by the demonstration that the cytoplasm of chondrocytes reacted with the specific Apo A-I probe used for in situ hybridization and was immunostained by the anti-Apo A-I antiserum. CONCLUSION: Amyloid in the knee joint menisci is formed from Apo A-I that is produced by chondrocytes within the meniscal cartilage. This entity represents yet another localized form of amyloidosis associated with the aging process and may be of pathophysiologic import.
Adult↗
Characterization of systemic amyloid deposits by mass spectrometry.
The human systemic (noncerebral) amyloidoses represent a heterogeneous group of disorders characterized by the widespread deposition of proteins as fibrils in organs or tissues throughout the body. The unequivocal identification of the type of amyloid deposited is critical to the correct diagnosis and treatment of patients with these illnesses. Heretofore, this information was inferred from clinical data, ancillary laboratory tests, and results of immunohistochemical, as well as genetic, analyses. However, to establish definitively the type of amyloid present, the chemical composition of the fibrillar components must be determined. For this purpose, we have developed micro-methods, whereby this information can be obtained by tandem mass spectrometry (MS/MS) using material extracted from formalin-fixed, amyloid-containing tissue biopsy specimens or subcutaneous fat aspirates. The ability to identify precisely the protein nature of the pathologic deposits has diagnostic, therapeutic, and prognostic implications for patients with amyloid-associated disease.
Amyloid↗
Micro-imaging of amyloid in mice.
Scintigraphic imaging of radioiodinated serum amyloid P-component is a proven method for the clinical detection of peripheral amyloid deposits (Hawkins et al., 1990). However, the inability to perform comparably high-resolution studies in experimental animal models of amyloid disease has impacted not only basic studies into the pathogenesis of amyloidosis but also in the preclinical in vivo evaluation of potential anti-amyloid therapeutic agents. We have developed microimaging technologies, implemented novel computational methods, and established protocols to generate high-resolution images of amyloid deposits in mice. (125)I-labeled serum amyloid P component (SAP) and an amyloid-fibril reactive murine monoclonal antibody (designated 11-1F4) have been used successfully to acquire high-resolution single photon emission computed tomographic (SPECT) images that, when fused with x-ray computed tomographic (CT) data, have provided precise anatomical localization of secondary (AA) and primary (AL) amyloid deposits in mouse models of these diseases. This chapter will provide detailed protocols for the radioiodination and purification of amyloidophilic proteins and the generation of mouse models of AA and AL amyloidosis. A brief description of the available hardware and the parameters used to acquire high-resolution microSPECT and CT images is presented, and the tools used to perform image reconstruction and visualization that permit the analysis and presentation of image data are discussed. Finally, we provide established methods for measuring organ- and tissue-specific activities with which to corroborate the microSPECT and CT images.
Amyloid↗
Isolated amyloidosis presenting with lumbosacral radiculoplexopathy: description of two cases and pathogenic review.
In this study, we present two cases of infiltrative, localized amyloidosis involving lumbosacral root and plexus, e.g., isolated amyloidomas. Rare and poorly understood amyloidomas may occur in both neurologic and non-neurologic tissues. The described cases emphasize potential for localized peripheral amyloidomas: (1) potential for associated lambda light chain lymphoplasmacytic lymphoma association; (2) e isolated amyloidosis without evidence for systemic plasma cell dyscrasia; (3) features suggestive of potential pathogenesis; and (4) discussion of treatment options including immunotherapy and resection. The limited literature and experience among other cases is described.
Aged↗
Radioimaging of light chain amyloid with a fibril-reactive monoclonal antibody.
UNLABELLED: Currently, there are no available means in the United States to document objectively the location and extent of amyloid deposits in patients with systemic forms of amyloidosis. To address this limitation, we have developed a novel diagnostic strategy, namely, the use of a radiolabeled fibril-reactive murine monoclonal antibody (mAb) as an amyloid-specific imaging agent. The goal of this study was to determine the pharmacokinetics, biodistribution, and ability of this reagent to target the type of amyloid that is formed from immunoglobulin light chains, that is, AL. METHODS: Subcutaneous tumors (amyloidomas) were induced in BALB/c mice by injection of human AL fibrils. The IgG1 mAb designated 11-1F4 and an isotype-matched control antibody were radioiodinated, and the pharmacokinetics and localization of these reagents were determined from blood and tissue samples. Amyloidoma-bearing animals that received (125)I- or (124)I-labeled antibodies were imaged by whole-body small-animal SPECT/CT or small-animal PET/CT technology, respectively. RESULTS: Radioiodinated mAb 11-1F4 retained immunoreactivity, as evidenced by its subnanomolar affinity for light chains immobilized on 96-well microtiter plates and for beads conjugated with a light chain-related peptide. Additionally, after intravenous administration, the labeled reagents had the expected biologic half-life of murine IgG1, with monoexponential whole-body clearance kinetics. In the amyloidoma mouse model, (125)I-11-1F4 was predominately localized in the tumors, as demonstrated in biodistribution and autoradiographic analyses. The mean uptake of this reagent, that is, the percentage injected dose per gram of tissue, 72 h after injection was significantly higher for amyloid than for skeletal muscle, spleen, kidney, heart, liver, or other tissue samples. Notably, the accumulation within the amyloidomas of (125)I- or (124)I-11-1F4 was readily visible in the fused small-animal SPECT/CT or small-animal PET/CT images, respectively. CONCLUSION: Our studies demonstrate the amyloid-imaging capability of a radiolabeled fibril-reactive mAb and provide the basis for a clinical trial designed to determine its diagnostic potential in patients with AL amyloidosis and other systemic amyloidoses.
Amyloid↗
Elicitation of allergic asthma by immunoglobulin free light chains.
The observation that only 50% of patients with adult asthma manifest atopy indicates that other inflammatory mechanisms are likely involved in producing the characteristic features of this disorder; namely reversible airway obstruction, hyperresponsiveness, and pulmonary inflammation. Our recent discovery that antigen-specific Ig free light chains (LCs) mediate hypersensitivity-like responses suggests that these molecules may be of import in the pathophysiology of asthma. Using a murine experimental model of nonatopic asthma, we now have shown that an LC antagonist, the 9-mer peptide F991, can abrogate the development of airway obstruction, hyperresponsiveness, and pulmonary inflammation. Further, passive immunization with antigen-specific LCs and subsequent airway challenge can elicit a mast cell-dependent reaction leading to acute bronchoconstriction. These findings, and the demonstration that the concentration of free kappa LCs in the sera of patients with adult asthma were significantly increased (as compared with age-matched nonasthmatic individuals), provide previously undescribed insight into the pathogenesis of asthma. In addition, the ability to inhibit pharmacologically LC-induced mast cell activation provides a therapeutic means to prevent or ameliorate the adverse bronchopulmonary manifestations of this incapacitating disorder.
Animals↗
Definition of organ involvement and treatment response in immunoglobulin light chain amyloidosis (AL): a consensus opinion from the 10th International Symposium on Amyloid and Amyloidosis, Tours, France, 18-22 April 2004.
We undertook this study to develop uniformly accepted criteria for the definition of organ involvement and response for patients on treatment protocols for immunoglobulin light-chain amyloidosis (AL). A consensus panel was convened comprising 13 specialists actively involved in the treatment of patients with amyloidosis. Institutional criteria were submitted from each, and a consensus was developed defining each organ involved and the criteria for response. Specific criteria have been developed with agreed on definitions of organ and hematologic response as a result of discussions at the 10th International Symposium on Amyloid and Amyloidosis held in Tours, France, April 2004. These criteria now form the working definition of involvement and response for the purposes of future data collection and reporting. We report criteria that centers can now use to define organ involvement and uniform response criteria for reporting outcomes in patients with light-chain AL.
Amyloid↗
Amyloid deposits in transthyretin-derived amyloidosis: cleaved transthyretin is associated with distinct amyloid morphology.
The pathological fibrillar deposits found in the heart and other organs of patients with senile systemic amyloidosis (SSA) and Swedish familial amyloidotic polyneuropathy (FAP) contain wild-type (wt) and a mutant form of transthyretin (TTR), respectively. Previously, it was reported that these two forms of amyloid have different molecular features and it was thus postulated that the mechanism responsible for TTR fibrillogenesis in SSA and FAP may differ. To document further the nature of the amyloid in these entities, detailed morphological, histochemical, immunological, and structural analyses of specimens obtained from 14 individuals with SSA and 11 Swedish FAP patients have been performed. Two distinct patterns of amyloid deposition (designated A and B) were evident. In pattern A, found in all SSA and five of 11 FAP cases, the amyloid had a homogeneous but patchy distribution within the sub-endocardium, sub-epicardium, and myocardium; exhibited weak congophilia and green birefringence; and was composed of tightly packed, short, unorientated fibrils. This material contained mainly approximately 79-residue C-terminal fragments of the amyloidogenic precursor protein. In pattern B, seen in the six other FAP patients, the amyloid appeared as thin streaks throughout the cardiac tissue; often surrounded individual muscle cells; was strongly congophilic and birefringent; had long fibrils arranged in parallel bundles, often penetrating into myocytes; and was composed of virtually intact TTR molecules. These findings provide substantive evidence for the morphological and structural heterogeneity of TTR fibrils and suggest that the two types of deposition may reflect fundamental differences in the pathogenesis of the TTR-associated amyloidoses.
Adult↗
Senile seminal vesicle amyloid is derived from semenogelin I.
Senile seminal vesicle amyloid (SSVA), one of the most common forms of localized amyloidosis, is associated with the male aging process. Although it had been posited that the amyloidogenic component originated from exocrine cells and that, on the basis of immunohistochemistry, that the amyloid was composed of lactoferrin, the nature of SSVA was never established definitively. To address this issue, we have used our microanalytic techniques to characterize the structure of the congophilic green birefringent protein extracted from 5 such amyloid-containing specimens. Mass spectrometric analysis revealed that in all cases, the fibrils were composed mainly of polypeptide fragments identical in sequence to the N-terminal portion of the major secretory product of seminal vesicles, namely semenogelin I (SgI). Although lactoferrin was detected in 3 instances, the trace amount and seemingly intact form of this molecule indicated that it was not the amyloidogenic molecule. The SgI nature of the amyloid was confirmed through demonstration that the deposits were immunostained specifically with Sgl-reactive antibodies. The results of our research provide unequivocal evidence that SSVA is derived from SgI, and we provisionally designate this form of amyloidosis as ASgI.
Aged↗
Quantitative high-resolution microradiographic imaging of amyloid deposits in a novel murine model of AA amyloidosis.
The mouse model of experimentally induced systemic AA amyloidosis is long established, well validated, and closely analogous to the human form of this disease. However, the induction of amyloid by experimental inflammation is unpredictable, inconsistent, and difficult to modulate. We have previously shown that murine AA amyloid deposits can be imaged using iodine-123 labeled SAP scintigraphy and report here substantial refinements in both the imaging technology and the mouse model itself. In this regard, we have generated a novel prototype of AA amyloid in which mice expressing the human interleukin 6 gene, when given amyloid enhancing factor, develop extensive and progressive systemic AA deposition without an inflammatory stimulus, i.e., a transgenic rapidly inducible amyloid disease (TRIAD) mouse. Additionally, we have constructed high-resolution micro single photon emission computed tomography (SPECT)/computed tomography (CT) instrumentation that provides images revealing the precise anatomic location of amyloid deposits labeled by radioiodinated serum amyloid P component (SAP). Based on reconstructed microSPECT/CT images, as well as autoradiographic, isotope biodistribution, and quantitative histochemical analyses, the (125)I-labeled SAP tracer bound specifically to hepatic and splenic amyloid in the TRIAD animals. The ability to discern radiographically the extent of amyloid burden in the TRIAD model provides a unique opportunity to evaluate the therapeutic efficacy of pharmacologic compounds designed to inhibit fibril formation or effect amyloid resolution.
Amyloid↗
Chemical typing of porcine systemic amyloid as AA-amyloid.
Systemic AA amyloidosis is frequently reported in a wide variety of domestic and wild animal species. Porcine amyloidosis is rare and the amyloid has not been typed chemically thus far. In the present study, we have extracted porcine amyloid from formalin-fixed tissue sections. By subsequent amino acid sequencing, an N-terminal fragment was obtained identifying porcine systemic amyloid as AA amyloid. The N-terminal sequence had a great homology to bovine and ovine SAA1, suggesting that pig AA amyloid is derived from the systemic isoform of SAA. It is argued that the low incidence of amyloidosis in pigs is not likely to be attributed to unique features of porcine amyloid precursor protein. Elucidation of the basis for the high apparent resistance of pigs against amyloidosis may yield important clues for treatment and prevention of amyloidosis in other species. This is the first report on chemical identification of porcine amyloid.
Amino Acid Sequence↗
Clinical efficacy of high-dose dexamethasone with maintenance dexamethasone/alpha interferon in patients with primary systemic amyloidosis: results of United States Intergroup Trial Southwest Oncology Group (SWOG) S9628.
Current therapy of primary systemic (AL) amyloidosis with oral melphalan and prednisone remains unsatisfactory, with a median survival of only 13 months. Between 1996 and 2003, 93 patients with biopsy-proven AL amyloidosis were enrolled in a prospective US national cooperative group trial. Treatment schema consisted of induction therapy with pulse dexamethasone (DEX), followed by maintenance therapy with DEX and alpha interferon. Hematologic complete remissions were observed in 24% and improvement in AL amyloidosis-related organ dysfunction occurred in 45% of patients evaluable for response. Median survival of the entire cohort is 31 months, with an estimated 2-year overall survival (OS) and event-free survival (EFS) of 60% and 52%, respectively. Presence of congestive heart failure and increased level of serum beta2 microglobulin (>/= 0.0035 g/L [3.5 mg/L]) were dominant predictors of adverse outcome. Estimated 2-year OS in patients who are eligible to receive transplants with this approach was 78%. These data demonstrate for the first time in the context of a US multicenter prospective clinical trial that front-line therapy with a DEX-based regimen in AL amyloidosis can lead to durable reversal of AL amyloidosis-related organ dysfunction and prolonged survival.
Aged↗
A molecular basis for nonsecretory myeloma.
The biosynthesis of aberrant immunoglobulin polypeptides by monoclonal plasma cells has been implicated in the pathogenesis of nonsecretory myeloma. Our studies of a patient with this disorder indeed have demonstrated the presence of abnormal kappa light chains that resulted from a frameshift mutation in nucleotides encoding the constant region of the molecule. As a consequence of a 2-base deletion in codon 187 and loss of the normal stop codon, this portion of the kappa chain was composed of 128 amino acids (rather than the expected 106), with a completely anomalous sequence after position 187 that included absence of the cysteines required for intrachain and interchain disulfide bonds. The unusual primary structure of this component was confirmed by mass spectrometric and amino acid sequence analyses of cytoplasmic protein extracts. Our studies provide the first evidence that human nonsecretory myeloma may result from an alteration in the light-chain constant region.
Amino Acid Sequence↗
Two different types of amyloid deposits--apolipoprotein A-IV and transthyretin--in a patient with systemic amyloidosis.
Certain forms of systemic amyloidosis have been associated with the pathologic deposition as fibrils of three different apolipoprotein-related proteins--apolipoprotein A-I, apolipoprotein A-II, and serum amyloid A. We have previously reported (Bergström et al, Biochem Biophys Res Commun 2001;285:903-908) that amyloid fibrils extracted from the heart of an elderly male with senile systemic amyloidosis contained, in addition to wild-type transthyretin-related molecules, an N-terminal fragment of yet a fourth apolipoprotein--apolipoprotein A-IV (apoA-IV). We now provide the results of our studies that have established the complete amino-acid sequence of this approximately 70-residue component and, additionally, have shown this protein to be the product of an unmutated apoA-IV gene. Notably, the apoA-IV and transthyretin fibrils were not codeposited but, rather, had anatomically distinct patterns of distribution within the heart and other organs, as evidenced immunohistochemically, by variation in the ultra structural morphology and by differences in the intensity of Congo red birefringence. These findings provide the first conclusive evidence that two separate forms of amyloid, each derived from a wild-type amyloidogenic precursor protein, were present in a patient with systemic amyloidosis.
Aged↗
Renal apolipoprotein A-I amyloidosis associated with a novel mutant Leu64Pro.
Apolipoprotein A-I amyloidosis (Apo A-I) is an inherited systemic disease that results from the pathologic deposition in tissues throughout the body of fibrils composed of Apo A-I-related molecules. This disorder has been linked to mutations occurring within the coding region of the Apo A-I gene and, to date, 11 such substitutions have been documented. In 4 of these cases, the kidney was the target organ of the disease process. The authors report their studies on a patient with renal amyloidosis and a heretofore undescribed alteration in the amyloidogenic precursor protein. Analyses of genomic DNA evidenced a transition in the second base of codon 64 (T-->C) in one Apo A-I allele that resulted in the replacement of leucine by proline at position 64 (Leu64Pro). Additionally, fibrils extracted from the kidney and characterized chemically were found to be composed almost exclusively of an approximately 96-residue N-terminal Apo A-I fragment that contained the Leu64Pro substitution. These studies have provided further evidence for Apo A-I amyloidogenicity and the propensity of certain mutants to deposit in renal parenchyma.
Amino Acid Substitution↗
Therapeutic potential of chimeric amyloid-reactive monoclonal antibody 11-1F4.
PURPOSE: We had previously reported that certain of our murine (m) antihuman light chain monoclonal antibodies (mAbs) recognized an epitope common to AL and other types of amyloid fibrils. On the basis of this evidence, one such antibody, 11-1F4, was administered to mice bearing AL amyloidomas induced by s.c. injection of human AL extracts. The mAb bound to the amyloid and initiated an Fc-mediated cellular inflammatory response that led to rapid reduction in the tumor masses. To develop this reagent for clinical use, the 11-1F4 mAb was chimerized and its activity compared with that of the unmodified antibody. EXPERIMENTAL DESIGN: The chimeric (c) 11-1F4 mAb was produced in CHOdhfr-stable mammalian cell lines that had been transfected with a supervector DNA encoding the mouse 11-1F4 heavy and light chain variable regions (V(H), V(L)) and human heavy and light chain constant regions (C(H), C(L)). The antibody products were analyzed for their fibril binding activity and ability to effect amyloidolysis in two in vivo experimental models. RESULTS: The capability of the c11-1F4 mAb to interact with amyloid was demonstrated in vitro. Administration of this reagent into mice bearing human AL tumors or those with systemic AA deposits resulted in marked reduction in amyloid burden with no evidence of toxicity in the animals. CONCLUSIONS: These results have led to the decision to produce GMP-grade c11-1F4 for a Phase I/II clinical trial in patients with primary (AL) amyloidosis where the effectiveness of the reagent could be determined. The use of amyloid-reactive antibodies would represent a novel approach in the treatment of individuals with this invariably fatal disorder.
Amyloid↗