Chronic arthritis and gamma heavy chain disease: coincidence or pathogenic link?

In 1991, gamma heavy chain disease was diagnosed in a 43-year-old female, who 3 years earlier had contracted an erosive seronegative chronic arthropathy. Her gamma heavy chain disease had a benign course, requiring no specific therapy for 5 years. In 1996, however, her lymphoproliferative disorder underwent a more malignant course, with renal and cardiac failure and increasing articular problems, requiring treatment with melphalan and prednisolone, following the protocol for myelomatosis. Laboratory studies revealed a monoclonal component in serum and urine. consistent with dimers of gamma-chains of the gamma3 subclass, but with a smaller molecular mass than normal gamma3-chains, suggesting molecular aberrations as consistently observed in this disorder. Massive localization of plasma cells and blasts with cytoplasmic or cell membrane staining for gamma3-chains, but no staining for kappa or lambda light chains, was observed by immunohistochemical studies of tissue specimens from bone marrow as well as affected synovial tissue. Large amounts of extracellular gamma3-chains were deposited in the synovial membrane. In addition, marked inflammatory changes with synovial cell hyperplasia were seen. Whether the present case represents primarily a gamma heavy chain deposition disease with reactive inflammatory changes in the joints, or another example of gamma heavy chain disease preceded by seronegative rheumatoid arthritis, remains elusive. Regardless, a possible pathogenic link between the two disease processes is an intriguing possibility.

Experimental AA-amyloidosis in mice is inhibited by treatment with the anti-rheumatic drug tenidap.

In a mouse model for induction of experimental AA-amyloidosis, treatment with tenidap was shown to inhibit the development of amyloidosis. Studies have shown that the drug inhibits the cytokines interleukin (IL)-6, IL-1 and tumour necrosis factor alpha (TNF-alpha) which are known to stimulate hepatocytes to synthesize acute phase proteins (APPs). The APP serum amyloid protein (SAA) is the precursor for amyloid protein AA and tenidap treatment reduces the serum levels of SAA in mouse and humans. It is suggested that reduction of SAA levels reduces the risk of AA fibril formation and thus the development of amyloidosis.

Brefeldin A inhibits experimentally induced AA amyloidosis.

OBJECTIVE: Brefeldin A, an antibiotic with effects on certain intracellular compartments, was tested on murine secondary AA amyloidosis. Effects on splenic proteoglycan metabolism were analyzed along with plasma serum amyloid A (SAA) levels. METHODS: Brefeldin A was administered daily to mice undergoing inflammatory stimulation with complete Freund's adjuvant to induce reactive AA amyloidosis. AA amyloid deposition was assessed using histochemistry, immunohistochemistry, and electron microscopy. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blotting were used to detect SAA in acute phase serum. Relative (semiquantitative) measurements of total SAA levels were obtained by densitometry of stained gels. Splenic proteoglycan metabolism was analyzed in treated animals and compared to untreated individuals by in vivo 35S administration during amyloid fibrillogenesis. RESULTS: Based on (immuno)histochemistry and electron microscopy, animals undergoing drug treatment did not develop splenic amyloidosis, whereas the control animals exhibited massive amyloid fibril deposits in the spleen (p < 0.001). SAA was detected at roughly equal quantities in serum from both groups. No significant qualitative or quantitative difference in proteoglycan synthesis was found. CONCLUSION: Brefeldin A seems to exert an inhibitory action on murine AA amyloidosis. It appears that the effect does not depend on the lack of fibril protein precursor nor altered proteoglycan synthesis.

[Adult-onset Still's disease. An underdiagnosed condition?]. / Stills sykdom i voksen alder. En underdiagnostisert tilstand?

Adult onset Still's disease is a variant of systemic juvenile chronic arthritis in adulthood. The clinical picture is characterized by high spiking fever, arthralgia/arthritis, transient erythema, acute-phase reaction including elevated ESR, CRP and neutrophilia, resembling acute bacterial infections. Hyperferritinaemia and hepatic dysfunction are usually present, and the patients frequently have a sore throat. Extraarticular features, such as splenomegalia, serositis and pericarditis may be parts of this disease as well. Two cases are described, who were admitted to the Department of Internal Medicine of a small Norwegian hospital. Both patients were subjected to exhaustive and laborious investigations for the purpose of disclosing malignancy and/or septicaemia. Following adequate glucocorticoid therapy, both were asymptomatic after less than a week's treatment and after five months' follow-up. Two sets of diagnostic criteria are presented, having different sensitivity, although almost equal specificity. Still's disease in the adult may be an underdiagnosed clinical entity, but should definitely be considered to be a possible differential diagnosis when investigating suspected malignancy, including lymphoma and febrile conditions suspected of septicaemia.

Characterization of proteoglycans associated with mouse splenic AA amyloidosis.

We here report for the first time on the chemical characteristics of proteoglycans associated with mouse splenic reactive AA amyloid. Amyloid was induced in CBA/J mice by two different procedures; conventional casein treatment and by employing Freund's complete adjuvant, accelerated by Trypan Blue. Pulse-labelling was employed at distinct stages during amyloid development, followed by [35S]proteoglycan characterization of organ extracts. Repetitive 35S injections were also administered during the phase where amyloid deposition occurred most rapidly. Proteoglycans were extracted with guanidine in the presence of protease inhibitors and purified. The results showed that the production of proteoglycans is dramatically enhanced during amyloidogenesis, the glycosaminoglycan and proteoglycan accumulation being not only dependent on alterations in proteoglycan catabolism, but rather on increased synthesis. The increment could be demonstrated even at the stage before microscopic detection of amyloid deposits, clearly suggesting that the upregulation of proteoglycan expression precedes amyloid fibril formation. Two major proteoglycans were found to accumulate in advanced splenic amyloid; one a heparan sulphate proteoglycan of approx. 200 kDa with a core protein of 70 kDa, the other a chondroitin sulphate proteoglycan of smaller size. Moreover, free dermatan sulphate chains seemed to specifically accumulate in the organs during amyloid fibrillogenesis. We suggest that free glycosaminoglycans may be a specific feature of amyloidosis and that different proteoglycans and glycosaminoglycans play a role in formation and stabilization of amyloid fibrils in vivo.

Interaction between circulating amyloid fibril protein precursors and extracellular tissue matrix components in the pathogenesis of systemic amyloidosis.

Amyloidosis is a heterogeneous group of diseases characterized by deposition of a fibrillar, proteinaceous material, amyloid, in various tissues and organs. Increasing knowledge about the different proteins that constitute the amyloid fibrils has made it possible to classify amyloidosis by the fibril protein, which appears more rational than the traditional classification by its clinical expression. A serum protein is the precursor of the amyloid fibril protein in the various systemic forms of amyloidosis. Although the chemical composition of amyloid is presently well known, the pathogenetic processes that convert such proteins into a fibrillar form and lay them down in the tissues are far from clarified. We suggest some pathogenetic mechanisms for amyloid deposition, involving different types of fibril protein, their precursors, the extra-fibrillar amyloid P component, glycosaminoglycans, proteoglycans, and calcium with special reference to experimental work from our research group.

On the association between amyloid fibrils and glycosaminoglycans; possible interactive role of Ca2+ and amyloid P-component.

We have previously reported the specific association of glycosaminoglycans (GAG) and proteoglycans (PG) with amyloid fibrils and characterized the polysaccharides directly extracted from amyloid-laden tissues. In the present study we further elucidate the association between purified amyloid fibrils and GAG/PG with special reference to those GAG/PG associated with amyloid P-component (AP) and the interactive role of Ca2+ ions. Amyloid fibrils were isolated from human hepatic AA amyloid employing water extraction with and without preceding removal of AP, an extrafibrillar protein component of all amyloids, using sodium citrate. GAG/PG co-isolated with the amyloid extracts, with and without AP, were isolated and characterized. Agarose-affinity chromatography of extracts containing AP was performed, and the GAG associated with this extrafibrillary protein were characterized as well. Several different GAG/PG populations were demonstrated in the various extracts. The abolition of calcium-dependent binding markedly influenced the amount of GAG/PG recovered in the fibril extracts, as well as the total amount of amyloid material obtained. Thus, it seems that calcium plays an important role in the association between the fibrils and the sugar moieties, and that a significant fraction of the GAG found in amyloid exhibits a Ca(2+)-dependent fibril-GAG interaction. No significant difference in the proportion between galactosaminoglycans and glucosamines was, however, disclosed when the two extraction protocols were compared, suggesting that no particular GAG species has a higher affinity for the fibrils themselves. Both dermatan/chondroitin sulphate and heparan sulphate identified in the present study exhibited a Ca(2+)-dependent interaction with AP, supporting previous findings. However, the amyloid-associated galactosaminoglycans found, especially the large PG appearing in small amounts, seemed to have a higher affinity for the extrafibrillar AP than the other GAG.

Purification of amyloid-associated heparan sulphate proteoglycans and galactosaminoglycan free chains from human tissues.

Basement membrane-associated heparan sulphate proteoglycans have been demonstrated immunohistochemically in organs from patients afflicted with various types of amyloidosis. In a recent report, we were able to isolate and partly characterize a basement membrane-associated heparin sulphate proteoglycan from human hepatic amyloid. In the present study proteoglycans were extracted with guanidine from human amyloid-laden kidney, spleen and lymph nodes. All tissues extracted with guanidine contained both heparan sulphate proteoglycan (HSPG) and galactosaminoglycan (CS/DS) free chains. Tissue staining using a monoclonal antibody against basement membrane HSPG revealed the presence of HSPG in amyloid deposits in kidney and spleen. Furthermore, following SDS-PAGE of HSPG from kidney after deaminative cleavage of the HS chains, a 15-kDa and 80-kDa protein appeared, probably representing the core protein(s). In lymph node HSPG, three core proteins of 65, 30 and 25 kDa could be demonstrated on SDS-PAGE, the first reacting with the anti-basement membrane HSPG antibody when subjected to Western blotting subsequent to SDS-PAGE. By immunohistochemistry, we failed to demonstrate any staining of the renal and splenic tissue sections employing an antibody against the decorin core protein.

Isolation and partial characterization of heparan sulphate proteoglycans from human hepatic amyloid.

Proteoglycans were isolated from human amyloidotic liver by extraction with guanidine, followed by trichloroacetic acid precipitation, DEAE-Sephacel ion-exchange chromatography, and Sepharose CL-6B gel chromatography. A significant portion of the material was found to be free chondroitin/dermatan sulphate chains (30%), whereas the predominant part was heparan sulphate proteoglycan (HSPG) (70%). The approx. molecular mass of the HSPG was 200 kDa, as measured by gel electrophoresis and gel chromatography. The molecular mass of the core protein was shown to be 60 kDa by SDS/PAGE following de-aminative cleavage of the heparan sulphate chains. The heparan sulphate chains were liberated from the core protein by alkali treatment and found to have a molecular mass of approx. 35 kDa by Sepharose CL-6B gel chromatography. The core protein was shown, by immunoblotting, to react with a monoclonal antibody against bovine basement membrane HSPG. The presence of HSPG in amyloid deposits was further confirmed by immunohistochemistry on tissue sections from amyloidotic liver using the same antibody.

Macromolecular properties of glycosaminoglycans in primary AL amyloid fibril extracts of lymphoid tissue origin.

We have previously demonstrated the presence of glycosaminoglycans (GAGs) in water extracts of secondary AA amyloid fibrils. In the present study we isolated significant quantities of GAGs from fibril extracts of immunoglobulin light chain (AL) type derived from the spleens from two patients afflicted with primary amyloidosis. Employing ion-exchange chromatography and gel filtration subsequent to various specific chemical and enzymatic treatments, different types of high molecular weight GAGs were found in both preparations, but not in the corresponding normal splenic extracts. The amyloid-associated GAGs of the extracts derived from one patient consisted of 60% dermatan sulphate and 40% heparan sulphate whereas those obtained from the second spleen were 25% dermatan sulphate and 75% heparan sulphate. The heparan sulphate fraction occurred in the form of proteoglycans, whereas the dermatan sulphate apparently occurred as free GAG chains, resembling the data recently obtained from AA amyloid fibril extracts.

Glycosaminoglycans in extracts of cardiac amyloid fibrils from familial amyloid cardiomyopathy of Danish origin related to variant transthyretin Met 111.

We have previously demonstrated an association between secondary AA type amyloid fibrils and glycosaminoglycans (GAGs) in human liver. The present study was aimed at investigating whether a similar association could be demonstrated in isolated cardiac amyloid fibrils from a unique Danish family with amyloid cardiomyopathy related to variant transthyretin (TTR) with a single amino acid substitution of a methionin for leucine at position 111 (TTR Met 111). Using gel filtration and ion exchange chromatography, significant amounts of GAGs were detected in close association with purified myocardial amyloid fibrils, whereas only trace amounts of polysaccharides were present in the corresponding normal preparation. The GAGs were identified as 50% chondroitin sulfate, 33% heparin/heparan sulfate, and 17% hyaluronan. With the methods used the amyloid associated GAGs appeared as high molecular weight free polysaccharide chains, and not as part of intact proteoglycans (PGs) in the fibril extracts. We conclude that the association between purified amyloid fibrils and GAGs may be a general feature of amyloid deposits. Also, we suggest that the proportion of different GAGs in the amyloid deposits may depend both on the organ or tissues affected and the type of proteins making up the fibrils.

Identification of glycosaminoglycans in human renal and splenic secondary AA amyloid fibril preparations.

The evidence that glycosaminoglycans (GAGs) are specifically associated with amyloid, is strong. In the present study we looked for GAGs in water extracts of amyloid fibrils from kidney and spleen laden with AA amyloid secondary to ankylosing spondylitis. Significant amounts of high molecular weight GAGs were isolated from the fibril preparations of both organs using ion-exchange chromatography and gel filtration procedures. The polysaccharides present in purified human renal and splenic amyloid fibril material were characterized as follows: a) Sulphated GAGs of high molecular weight were found in both renal and splenic amyloid fibril extracts, but not in extracts from corresponding normal tissues. b) All of the renal amyloid-associated high molecular weight GAGs were chondroitin sulphate/dermatan sulphate, whereas splenic amyloid-associated high molecular weight GAGs had a chondroitin sulphate/dermatan sulphate:heparan sulphate ratio of approximately 2:1. c) The findings gave no evidence that GAGs coisolated with AA amyloid fibrils were parts of intact proteoglycan molecules with several GAG chains.