Noradrenergic and peptidergic nerves in the synovial membrane of the Sprague-Dawley rat

This immunohistochemical study of nerves in the synovial tissue of Sprague-Dawley rats demonstrated the occurrence of 4 neuropeptides and 2 enzymes that are involved in the synthesis of catecholamines. Substance P and calcitonin gene-related peptide were colocalized in fibers that terminated as varicosal endings in the synoviocyte layer. Similarly, tyrosine hydroxylase and dopamine beta-hydroxylase, which reflect the presence of noradrenaline, were colocalized with neuropeptide Y. These fibers were predominantly found adjacent to and within blood vessel walls. Immunoreactivity to vasoactive intestinal polypeptide was seen in varicose nerve terminals in the synoviocyte layer. Many were localized in vessel walls. There is accumulating evidence of an involvement of substance P and noradrenaline in the pathogenesis of inflammatory joint disease and nociception. The role of these colocalized neuropeptides, namely, calcitonin gene-related peptide and neuropeptide Y, in the pathophysiology of such conditions warrants further analysis.

Cathepsin B and cysteine protease inhibitors in human osteoarthritis

The aim of this study was to determine the involvement of cathepsin B and its inhibitors in the proteolytic degradation of human osteoarthritic (OA) tissue. The characteristics of the cathepsin B found in both normal and OA cartilage and synovium were similar to those of the lysosomal cathepsin B. Two inhibitors of cysteine proteases were found with a molecular weight of 67,000 and 16,000 Da. The cartilage cathepsin B level of OA specimens (54.8 +/- 7.3 units/micrograms of DNA) was greater than the controls (39.8 +/- 3.2 units/micrograms of DNA). Mild-moderate graded samples (78.1 +/- 12.0 units/micrograms of DNA) had significantly higher levels of enzyme activity than the severely graded ones (31.4 +/- 3.9 units/micrograms of DNA, p less than 0.001) and controls (p less than 0.01). Compared to controls (2.3 +/- 0.4 units/mg of tissue w.w.), cysteine protease inhibitory activity in OA cartilage was decreased in specimens with severe lesions (1.5 +/- 0.2 units/mg of tissue). This was particularly noted in patients who had not received steroid injections (1.2 +/- 0.3 units/mg of tissue, p less than 0.05). In OA synovia, the cathepsin B level was greater (40.7 +/- 7.4 units/mg of tissue w.w., p less than 0.02) than in the controls (13.6 +/- 3.7 units/mg of tissue). The cysteine protease inhibitory activity was similar in OA synovium (1.7 +/- 0.2 units/mg of tissue w.w.) and in controls (1.5 +/- 0.3 units/mg of tissue). This data demonstrated an imbalance between the levels of cathepsin B and cysteine protease inhibitors in OA tissue. A decrease of specific inhibitors could be an important contributing factor, particularly in more severe lesions.

Cellular fibronectin in rheumatoid synovium and synovial fluid: a possible factor contributing to lymphocytic infiltration

Mouse monoclonal antibodies against ED sequence-containing cellular fibronectin (cFn) were used to show that Fn in the inflamed synovium is distinct from the major form of plasma Fn (pFn). An accumulation of cFn was seen at sites of hyperplasia of the rheumatoid synovial membrane and in the walls of small vessels in the synovium by immunofluorescence microscopy. cFn was also found in rheumatoid synovial fluid by immunoblotting. Approximately one-fifth of the T lymphocytes from rheumatoid synovial fluid bound to Fn. The binding of synovial fluid T cells was always higher than that from peripheral blood. These results have two implications. On the one hand, the cellular type of Fn may be an indicator of synovial inflammation. On the other hand, the deposition of Fn may be a factor contributing to the infiltration of mononuclear cells into the synovium.

Salmonella lipopolysaccharide in synovial cells from patients with reactive arthritis

Synovial cells from nine patients with reactive arthritis following Salmonella enteritidis or Salmonella typhimurium infection were examined for salmonella antigens. Extensive bacterial cultures of the synovial fluid were negative. Eight synovial-fluid cell samples stained positively on immunofluorescence with rabbit antisera against heat-killed S enteritidis or S typhimurium or with monoclonal antibodies specific for the causative salmonella lipopolysaccharide (LPS). Synovial tissue from the ninth patient stained positively in the avidin-biotin-peroxidase complex method with the monoclonal antibody. Control samples (synovial-fluid cells from thirteen patients with other rheumatic diseases and synovial tissue from two) were negative. Synovial cells from eight patients and five controls were studied by western blotting with the same monoclonal antibodies. Four of the eight patients but no controls had blots indicating salmonella LPS in the synovial cells. The presence of bacterial LPS in the joint is a common and pathogenetically important feature of reactive arthritis.

Immunohistopathologic findings in synovial biopsies before and after synovectomy in patients with chronic inflammatory joint diseases and their relation to clinical evaluation. A prospective study of biopsies taken from areas selected by arthroscopy

Synovial biopsies were obtained from 28 patients with various kinds of chronic arthritis, at synovectomy and 6 and 12 months later. The tissues were examined by immunofluorescence technique, recording the quantities of cells and extracellular deposits staining with polyclonal antisera to IgG, IgA, IgM, C3c, fibrinogen, and chi and lambda light chains, and monoclonal antibodies to CD3, CD5, CD11b, HLA DR, and TCC (Terminal Complement Complex). These parameters were compared with scores obtained by arthroscopy and clinical evaluation (Colorado Knee Score) performed at the same time. Taken as a group, the immunological parameters showed reduction in activity 6 months after synovectomy (p less than 0.01), and a tendency to revert to base-line values after 12 months. A similar reduction in activity after 6 months was also found by arthroscopic and clinical evaluation. Thus, this longitudinal study demonstrated a relationship between changes in immunologic activity, arthroscopic findings and clinical activity after synovectomy in patients with chronic arthritis. This is consistent with an immunological pathogenesis for the inflammation in these joints.

Glycosaminoglycans of the hemodialysis-associated carpal synovial amyloid and of amyloid-rich tissues and fibrils of heart, liver, and spleen

Significant amounts of glycosaminoglycans (GAGs) were found in amyloid fibril preparations. Using two-dimensional electrophoresis to fractionate GAG mixtures, we quantified and identified for the first time the GAGs of the fibrils from carpal synovium of patients with amyloid associated with chronic hemodialysis. The total GAG content was small, but the GAG distribution (high relative content of chondroitin sulfate and hyaluronic acid and lack of the other GAGs) was unique, unlike that for the other amyloid fibril preparations. The amyloid-rich heart, liver, and spleen tissues, as well as the fibrils isolated from these tissues of patients with systemic forms (primary amyloid and secondary amyloid) of amyloid disease, were also analyzed for GAGs. Fibrils from heart tissue of a patient with primary amyloidosis, now examined for the first time, contained four major GAGs (chondroitin sulfate, dermatan sulfate, hyaluronic acid, and heparan sulfate).

Localisation of lysozyme mRNA in rheumatoid synovial membrane by in situ hybridisation

Type A synovial lining cells have been shown to contain lysozyme in their lysosomes. This might be phagocytosed because synovial fluid contains lysozyme originating from tissue macrophages and articular cartilage but in arthritides, in particular, from neutrophils. In situ hybridisation with 35S labelled cDNA was used to detect mRNA for lysozyme over synovial lining in patients with rheumatoid arthritis. No hybridisation was found with lactoferrin cDNA, which was used as a negative control. Computer search against the EMBL gene bank (release 14) did not show any significant cross hybridisation to a known sequence. In cytological specimens 35S-cDNA:mRNA hybrids were observed in positive but not in negative control cells. The presence of lysozyme and its mRNA suggests that type A synovial lining cells are of mononuclear phagocyte lineage.

Human epidermal growth factor for the stratification of synovial lining layer and neovascularisation in rheumatoid arthritis

Immunohistochemical study showed selective localisation of human epidermal growth factor (hEGF) to the synovial lining layer. Although the synovial lining layer of the rheumatoid, osteoarthritic, and traumatic joints was hEGF positive, hEGF staining was especially dense at the rheumatoid synovial lining layer; the staining increasing linearly according to the degree of stratification of the lining layer (r = 1). Human epidermal growth factor was ultrastructurally localised to cytoplasm, especially to rough endoplasmic reticulum, of the synovial lining fibroblast-like (type B) cell. Only the cell surface of macrophage-like (type A) cells was hEGF positive. When different histological variables were compared with each other a positive correlation was found between hEGF staining of the synovial lining layer and the degree of neovascularisation of rheumatoid synovium (r = 0.72). Although some lymphocytes were weakly hEGF positive, neovascularisation did not correlate with the extent of lymphocyte infiltration or of hEGF staining of lymphocytes. Lymphocyte infiltration or hEGF staining of lymphocytes did not correlate with hEGF staining of the synovial lining layer, whereas the lymphocyte infiltration correlated positively with the extent of perivascular accumulation of lymphocytes (r = 0.89). These findings suggest that (a) hEGF is synthesised by and secreted through endoplasmic reticulum and Golgi apparatus from the synovial lining type B cell; (b) hEGF is at least partially responsible for the pathogenesis of stratification of the rheumatoid synovial lining layer, and perhaps of neovascularisation of the rheumatoid synovium, whereas it is not responsible for lymphocyte accumulation to the rheumatoid synovium.

Characteristics of tumor necrosis factor production in rheumatoid arthritis

The biological effects of tumor necrosis factor (TNF) include the enhancement of fibroblast proliferation, the secretion of collagenase and prostaglandin E2 (PGE2) by fibroblasts, and the resorption of bone and cartilage, suggesting a role for this cytokine in arthritic conditions. To investigate this, we measured the levels of TNF in synovial fluids and evaluated its secretion by synovial fluid mononuclear cells and tissues from patients with rheumatoid arthritis, osteoarthritis, and seronegative arthritis and normals. TNF was found to be secreted in all arthritic conditions but not in normals. The levels of TNF were highest in synovial fluid and correlated with interferon-gamma (IFN-gamma) levels but not PGE2. The production of TNF was stable in a single joint for 3 to 6 months. Using immunohistochemical staining, TNF was localized to mononuclear cells in the lining layer, sublining, and perivascular areas of synovial tissue. The secretion of TNF by rheumatoid synovial fluid mononuclear cells was inhibited by PGE2, while IFN-gamma enhanced its production in those cells which were spontaneously secreting TNF. Our data suggest that TNF may play a role in various arthritic diseases.

Leukocyte migration in synovial tissue. Leukocyte distribution, orientation, and migratory pattern after immune complex deposition in rabbit knee joints

Complement-activating bovine serum albumin (BSA)-anti-BSA immune complexes (ICs) were injected into rabbit knee joint cavities; the contralateral control joint was injected with BSA together with normal rabbit serum. The migration of leukocytes from the synovial venules into the joint cavity was analyzed with light microscopy (LM), scanning (SEM) and transmission (TEM) electron microscopy. EM autoradiography was used to study the endocytosis of ICs by leukocytes. The shape, orientation, and distribution of migrating polymorphonuclear granulocytes (PMNGs) were analyzed by LM morphometry. PMNGs accumulated in the joints injected with ICs. The peak of the number of PMNGs in the synovial tissue was reached after 4 hours, in the joint cavity after 6 hours. PMNGs in the synovial tissue were concentrated in the intimal layer. Migrating PMNGs were polarized, as judged by the ratio between the long (D max) and short (D min) axes of the cells. There was a close association between the migrating PMNGs and the collagen fibers. The morphometric data showed that the nonflattened, cylindrically-shaped PMNGs were oriented along the collagen bundles, running parallel to the synovial surface, and did not migrate in the straight direction of a theoretic leukotactic gradient originating in the joint cavity after IC deposition. SEM and TEM showed that the PMNGs were aligned along the collagen fibers and interacted activity with the collagen by pseudopods and cytoplasmic projections. EM autoradiography showed that the PMNGs in the joint cavity had ingested 125I-labeled ICs and were degranulated. In contrast, the PMNGs within the synovial membrane did not show any signs of IC endocytosis or any apparent degranulation. Synovial type A cells were found to contain ICs. This study indicates that the response of PMNGs in IC-induced synovitis consists of two distinct phases: an initial, mainly migratory phase in the synovial membrane where the PMNGs appear to use the collagen fibres as a climbing framework, and a second phase, in the joint cavity, characterized by PMNG metabolic activation, endocytosis of ICs, and degranulation. The apparent inability of PMNGs in the synovial membrane to ingest ICs and become degranulated might be due to not only concentration differences of ICs and leukotactic factors between the joint cavity and the synovial tissue but also might be related to the apparently active interaction with collagen.

Presence of platelet glycoproteins Ib and IIb-IIIa in inflammatory and noninflammatory synovium

Rheumatoid synovial tissue and noninflammatory synovial tissue from patients with meniscus lesions were stained using monoclonal antibodies against platelet 150 kDa Ib glycoprotein (gp Ib) and against 140/110 kDa IIb-IIIa glycoprotein complex (gp IIb-IIIa) applied with the avidin-biotin-peroxidase complex method. Gp Ib and gp IIb-IIIa positive intravascular platelet aggregates were not seen, except locally in the capillary blood vessels of one rheumatoid synovial sample. This suggests that the platelets and the clotting sequence are not activated in inflamed synovial tissue. However, in many of the synovial capillaries endothelial immunoreactivity was seen. This reaction could have been due to cross reaction, since the vitronectin receptor beta chain is structurally identical to platelet gp IIIa. The gp IIb-IIIa member of the integrin receptor family plays a role in the transmembrane linkage between its extracellular ligands and intracellular microfibers. Gp IIb-IIIa may thus contribute to normal synovial physiology and to the pathogenesis of chronic synovitis.

Amyloid localized to tenosynovium at carpal tunnel release. Natural history of 124 cases

One hundred fifty-two patients with amyloid in the tenosynovium who had carpal tunnel release were identified. Twenty-eight patients were excluded because of systemic amyloidosis: primary systemic amyloidosis (AL) in 24, secondary amyloidosis (AA) in 3, and familial amyloidosis (AF) in 1. The remaining 124 patients (82%) had carpal tunnel syndrome with local deposition of amyloid and no evidence of systemic amyloidosis. Median survival of the 124 patients from diagnosis of amyloidosis was 12 years. Only two patients had systemic amyloidosis develop--9 and 10 years after recognition of tenosynovial amyloid. Of particular interest were 12 patients who had an M-protein in the serum or urine. None of the 12 patients have had evidence of systemic amyloidosis or multiple myeloma during the median follow-up of 14 years. The authors conclude that amyloid may be localized to the tenosynovium and that systemic amyloidosis rarely develops during long-term follow-up.

Beta-2-microglobulin-associated amyloidosis in chronic hemodialysis patients with carpal tunnel syndrome

The clinical manifestations of beta-2-microglobulin (beta 2M)-associated amyloidosis in chronic hemodialysis patients with carpal tunnel syndrome from a medical center hospital are presented. The predominant morbidity of beta 2M-amyloid was musculoskeletal, with deposits identified in surgical or biopsy specimens from trigger fingers, carpal tunnels, fractures, and radiolucent bone lesions. Lucent bone lesions were the characteristic radiologic finding of beta 2M-amyloidosis and were most commonly found in carpal bones, humeral heads, and femoral heads. Carpal tunnel syndrome occurred in greater than 20% of our chronic hemodialysis patients. The longer the period of time on chronic hemodialysis the greater the morbidity from beta 2M-amyloid. Although significant amounts of beta 2M-amyloid were detected in the perivascular regions of viscera, clinical compromise of internal organs from this type of amyloid was not documented. In acute studies, beta 2M clearance during hemodialysis was markedly increased using the Fresenius polysulfone dialyzers compared to cuprophane dialyzers. In summary, beta 2M-amyloid is common and causes significant morbidity in chronic hemodialysis patients. Long-term dialysis with highly permeable membranes effects greater beta 2M clearance which may result in less tissue deposition of beta 2M-amyloid, and therefore, fewer clinical complications.

A tumor-associated fibronectin isoform generated by alternative splicing of messenger RNA precursors

Fibronectin (FN) represents the mixture of a number of structurally different molecules (isoforms) whose make-up varies depending on the FN sources. FN from cultured transformed human cells has a very different isoform composition with respect to its normal counterpart. In fact, SV-40-transformed WI-38VAI3 human fibroblasts produce high levels of a FN isoform (B-FN) which is very poorly expressed in their normal, WI-38, counterpart. We have recently demonstrated that the B-FN isoform derives from a differential splicing pattern of the FN primary transcript which leads, in transformed cells, to a high level expression of the exon ED-B (Zardi, L., B. Carnemolla, A. Siri, T. E. Petersen, G. Paolella, G. Sebastio, and F. E. Baralle. 1987. EMBO (Eur. Mol. Biol. Organ.) J. 6:2337-2342). Here we report on the production and characterization of a monoclonal antibody (BC-1) which recognizes an epitope within the protein sequence coded for by the ED-B exon. This monoclonal antibody makes it possible to carry out immunohistochemical analysis of the distribution of the ED-B-containing FN isoform (B-FN) in human tissues. The results show that while in normal, adult, human tissues total FN has a widespread distribution, the B-FN isoform is restricted only to synovial cells, to some vessels and areas of the interstitium of the ovary, and to the myometrium. On the contrary, the B-FN isoform has a much greater expression in fetal and tumor tissues. These results demonstrate that, in vivo, different FN isoforms have a differential distribution and indicate that the B-FN isoform may play a role in ontogenesis and oncogenetic processes.

Epithelial markers in synovial sarcoma. An immunohistochemical study on paraffin embedded tissues

Immunohistochemical studies on synovial sarcomas have proved the potentiality of these neoplasm for epithelial and mesenchymal differentiation and antibodies detecting epithelial cells have been found to be helpful in determining the histological types. In this study different epithelial markers directed against various cytokeratins, HMFG-2 and EMA were investigated on paraffin embedded tissues of 13 cases of synovial sarcomas, with regard to their reliability in unmasking the epithelial components demonstrable in this type of neoplasm. The results lead to three conclusions: firstly, synovial sarcomas possess the capacity for generating different epithelial cell types with uncommon compositions of intermediate filaments as well as of membrane proteins, secondly, these features may be expressed in a heterogenous pattern even within the same tumour and finally, the use of wide range anti-cytokeratin antibodies covering the spectrum of basic as well as acidic type proteins seems to be necessary for the detection of all epithelial components demonstrable in synovial sarcomas.

Osteoarthrosis and apatite synovitis. Pathological study of a metacarpophalangeal joint

A case of metacarpophalangeal osteoarthrosis associated with synovial apatite deposits is reported. The size of the crystals indicates that they have been thickened by a recrystallization process; the latter could have been provoked by Ca and Po4 ions released by dissolution of some apatite crystals brought by calcified debris of bone or cartilage coming from the abraded osteoarthrotic surfaces. The role of such thickened crystals in synovial inflammation is discussed as well as their possible diagnostic value in determining origin and pathogenesis of a given synovial apatite deposit.

P component in the synovium in rheumatoid and osteoarthritis

P component is present in amyloid deposits, normal serum, and normal tissues in relation to elastic fibres. Its pathological role in inflammatory synovitis was investigated. Its distribution was determined immunohistologically in 33 synovia: 15 rheumatoid; seven osteoarthritic; seven traumatic controls; and four infected biopsy specimens. P component was present in two circumscribed distributions: extracellular fibrils in dense fibroelastic tissue of the more fibrotic synovia; and in the arterial wall, where it was confined to a single elastic lamina in some cases and in others showed reduplication and fragmentation. These were not related to amyloid material. It shows no disease specificity, but P component categorises the nature of the pathological reaction and is typically in biopsy specimens showing the development of chronic fibrosis. There was close codistribution of P component with elastic tissue, though this was not absolute. P component had a different distribution from C reactive protein (in synovial lining cell layer), and fibronectin, which was absent from fibrotic areas. Understanding the pathological interactions of P component may help elucidate why some synovial reactions remain inflammatory and other progress to chronic fibrosis.

Augmented interleukin-1 production and HLA-DR expression in the synovium of rheumatoid arthritis patients. Possible involvement in joint destruction

Potent interleukin-1 (IL-1) activity was detected in culture supernatants from synovium, obtained by arthroscopy, from rheumatoid arthritis (RA) patients but not from non-RA patients. Production of IL-1 by RA synovium correlated well with findings of inflammation on arthroscopy and HLA-DR expression in immunohistochemical staining. Furthermore, there was a positive correlation between IL-1 production from RA synovium and joint changes detected on roentgenograms. These findings strongly suggest that IL-1 might play an important role in the joint destruction in RA.

Metallic wear in failed titanium-alloy total hip replacements. A histological and quantitative analysis

We conducted extensive histological examination of the tissues that were adjacent to the prosthesis in nine hips that had a failed total arthroplasty. The prostheses were composed of titanium alloy (Ti-6Al-4V) and ultra-high molecular weight polyethylene. The average time that the prosthesis had been in place in the tissue was 33.5 months (range, eleven to fifty-seven months). Seven arthroplasties were revised because of aseptic loosening and two, for infection. In eight hips cement had been used and in one (that had a porous-coated implant for fifty-two months) no cement had been utilized. Intense histiocytic and plasma-cell reaction was noted in the pseudocapsular tissue. There was copious metallic staining of the lining cells. Polyethylene debris and particles of cement with concomitant giant-cell reaction were present in five hips. Atomic absorption spectrophotometry revealed values for titanium of fifty-sic to 3700 micrograms per gram of dry tissue (average, 1047 micrograms per gram; normal, zero microgram per gram), for aluminum of 2.1 to 396 micrograms per gram (average, 115 micrograms per gram; normal, zero micrograms per gram), and for vanadium of 2.9 to 220 micrograms per gram (average, sixty-seven micrograms per gram; normal, 1.2 micrograms per gram). The highest values were found in the hip in which surgical revision was performed at fifty-seven months. The concentrations of the three elements in the soft tissues were similar to those in the metal of the prostheses. The factors to which failure was attributed were: vertical orientation of the acetabular component (five hips), poor cementing technique on the femoral side (three hips), infection (two hips), and separation of a sintered pad made of pure titanium (one hip). A femoral component that is made of titanium alloy can undergo severe wear of the surface and on the stem, where it is loose, with liberation of potentially toxic local concentrations of metal debris into the surrounding tissues. It may contribute to infection and loosening.

Dissection of the mechanisms of immune injury in rheumatoid arthritis, using total lymphoid irradiation

Eleven patients with intractable rheumatoid arthritis were treated with total lymphoid irradiation. After radiotherapy, there was a marked decrease in the number and function of peripheral blood helper/inducer (Leu-3+) T lymphocytes, in the spontaneous secretion of interleukin-1 by synovial biopsy specimens, and in the activity of the joint disease. In contrast, levels of IgM, IgA, and IgG rheumatoid factors and C3 concentrations in blood and synovial fluid samples did not change significantly after therapy with total lymphoid irradiation.

Preservation of thrombomodulin antigen on vascular and extravascular surfaces

The protein C anticoagulant system is mediated by thrombin and is highly accelerated by thrombomodulin. We studied the distribution of thrombomodulin antigen (TM Ag) in the rabbit using an affinity-purified antibody raised in a goat against rabbit thrombomodulin. The preservation of TM Ag was highly dependent on immediate fixation of the surface on which it is located. TM Ag was found on the endothelium of the entire vasculature, whereas it was absent from all connective tissue, smooth and striated muscle, secretory epithelia, cartilage, bone, neural tissue, and all parenchyma examined. A new finding was the presence of TM Ag on nonvascular surfaces of body cavities (the mesothelia of pleura, pericardium, and peritoneum, the synovial membrane, and the arachnoid enveloping the central nervous system). By use of a functional assay, TM activity was recovered in buffered saline/detergent solution which was either injected into the intraperitoneal cavity of rabbits in vivo or incubated with the surface of the arachnoid in vitro. These findings extend the importance of anticoagulant mechanisms to the systems of slowly circulating fluids, in which they might be required for maintenance of the flow, and to mesothelial cavities, in which they could be necessary for preventing adherence between the surfaces, in conditions associated with pathological exudation.

[Study of articular cartilage and the synovial membrane using IR spectroscopy]

The infrared spectra of normal knee joint cartilage, normal and rheumatoid arthritis-affected human synovial membrane and the same normal bovine tissues were obtained over the region of 400--4000 cm-1. A comparative analysis of the spectra of these tissues and those containing hyaluronate, protein-chondroitin-keratan sulfate aggregates of cartilage proteoglycans and heparin made it possible to identify greater absorption bands of these biopolymers in the tissue spectra. The interpretation of the results obtained is presented.

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.

[Mononuclear phagocytic cells in human rheumatoid synovial membrane. Histochemical and immunohistological study]

Non specific immunity in human rheumatoid synovium: histochemical and immunohistological analysis. Enzymatic activities and monocyte-specific membrane antigens were looked for on frozen sections from 25 synovial membrane samples from patients with rheumatoid arthritis. Classical histochemical reactions were used to identify non specific esterases, alkaline and acid phosphatases, ATPase and peroxidase. Indirect immunofluorescence was performed with a series of monoclonal antibodies to monocyte membrane antigens and HLA class II molecules. Technical pitfalls were successfully overcome, and specific labelings demonstrated the variety and heterogeneity of these markers among synovial cells and vascular endothelia. Reported data indicated that such a panel of investigations is useful to better define the non-specific immunological phenomenons which take place in this active pathological tissue. They suggest that numerous metabolic activities concur to sustain chronic inflammation.

Dialysis arthropathy: amyloid or iron?

The clinical, biochemical, radiological, and pathological features in five cases of dialysis arthropathy were analysed. All patients were receiving long term haemodialysis and had had multiple blood transfusions. The arthropathy affected both large and small joints, was predominantly bilateral, and in all cases was associated with the carpal tunnel syndrome. In some instances joint pain was exacerbated during dialysis. In four cases the serum ferritin concentration was raised. Radiological examination showed a few juxta-articular cysts and erosions but most affected joints looked normal. All synovial tissue examined showed amyloid, which stained immunohistochemically for beta 2 microglobulin. Large amounts of iron were present in synovial tissue from affected joints. It is suggested that the deposits of iron, rather than amyloid, in synovial tissue may be the cause of the arthropathy. Iron may be derived locally as a result of haemarthrosis or it may be a manifestation of systemic iron overload.

[Effect of synovial extract from patients with rheumatoid arthritis on the proliferation of cultured chondrocytes]

To determine whether or not some growth factor (or factors) plays a significant role in the disease process of rheumatoid arthritis, the effects of pathological synovial extract, cultured synovial cell medium and partially purified extract and medium by fast protein liquid chromatography on cultured rabbit chondrocyte proliferation were studied. The synthesis of DNA was investigated by incorporation of 3H-thymidine into cultured cells and by flow cytometry using propidium iodide. The following results were obtained. The incorporation of 3H-thymidine into the cultured cells was increased by addition of synovial extract and the medium of cultured synovial cells. The molecular weights of active materials from the synovial extract were 13-18, 36-52, and 105-150 K daltons and those from the medium of cultured synovial cells were 13-18, 36-52 K daltons. The increase of S and G2 + M phase cells was observed flow-cytometrically 24-48 hr after addition of the synovial extract.

[Detection of cutaneously administered flufenamic acid in the inner space of the knee joint]

Ten patients who were scheduled for surgery due to an internal damage of the knee joint, were treated 2 days before operation 3 times daily with an ointment containing flufenamic acid (Mobilisin spezial). At the time of operation, plasma and synovial fluid, tissue samples from the synovial membrane, Hoffa's fat pad and-- as far as possible--meniscus and articular cartilage were taken. Until 72 h after the operation, urine samples were collected. The flufenamic acid level was determined by means of high pressure liquid chromatography associated with fluorometric detection. Flufenamic acid was detected in all tissues of the knee joint and in the synovial fluid. The highest concentration of flufenamic acid was found in the synovial membrane.

Neutral proteases in human osteoarthritic synovium

The activities of neutral collagenolytic enzymes (CE) and neutral proteoglycan-degrading enzymes (PE) in the synovial membranes of osteoarthritis (OA) patients were determined. The total neutral metallo-CE activity showed a significantly higher level of activity when the membranes of OA patients were compared with those of controls. The severely and moderately inflamed synovia had significantly more enzyme activity than did either mildly inflamed or control synovia. Steroids reduced the total metallo-CE activity. In specimens with severe inflammation, the active form of the neutral metallo-CE was significantly elevated over that found in controls. The serine-CE activity was also significantly elevated in OA synovia with severe inflammation and synovial hypertrophy. The total and active neutral metallo-PE was significantly elevated in synovial membranes of OA patients with severe inflammation. Moreover, the serine-PE showed much more activity in OA patients than in controls. The enzyme activity remained at a significantly high level in the OA synovium, regardless of the presence or absence of macroscopic synovial hypertrophy or the histologic grading of the synovium (mild, moderate, severe). Our data indicate that, in OA, an increased level of neutral proteases in the synovia could be involved in the local tissue destruction of the periarticular structures. Because of the very high level of serine proteases, their diffusion may render plausible a degradative action on the cartilage surface.

Characterization and functional studies of rheumatoid synovial mast cells. Activation by secretagogues, anti-IgE, and a histamine-releasing lymphokine

Microscopic analysis of synovial specimens from 35 patients with rheumatoid arthritis (RA) and 7 patients with osteoarthritis revealed mast cell hyperplasia in perivascular regions, in fibrous interstitial areas, and clustered around the periphery of lymphoid aggregates. Metachromatic staining, immunofluorescence studies, and ultrastructural analysis revealed a single population of connective tissue-type mast cells with surface IgE receptors. Total extractable histamine of synovial tissue was 4.15 +/- 2.30 micrograms/gm (n = 8) for RA synovium and 0.53 +/- 0.23 microgram/gm (n = 7) for OA synovium. Mast cell secretion was assessed and specific release of histamine from RA synovial mast cells was observed following stimulation with anti-IgE (32.3%), compound 48/80 (40.1%), calcium ionophore A23187 (25.2%), and a partially purified lymphokine with histamine-releasing activity (23.9%).

Metallothionein in cultured human epithelial cells and synovial rheumatoid fibroblasts after in vitro treatment with auranofin

Radioimmunoassay (RIA) and reversed-phase high-pressure liquid chromatography (HPLC) were used to investigate gold-binding proteins of possible metallothionein (MT) nature occurring upon auranofin exposure of cultured human cells. An epithelial cell line (HE) and two sub-strains were examined. The HEAF sub-strain had been made resistant to 2 mumole auranofin/l culture medium. The resistance was associated with the appearance of gold-binding substances with gel filtration characteristics like MT. The HE100 sub-strain had been made resistant to 100 mumole CdCl2/l and contained high amounts of cytosolic Cd-induced MT. In addition, cultured synovial fibroblasts, derived from normal (SN) and rheumatoid (SRA) synovial tissues, were investigated. Evidence was obtained by RIA that the low molecular weight (mol.wt. 6000-7000) gold-binding proteins occurring in the HEAF cells and SRA cells following auranofin exposure, were of MT nature. The relative amounts of MT in the epithelial cell lines were: HE:HEAF:HE100 = 1:18:100. The relative amounts in the synovial fibroblasts were: SN:SRA:SRA treated with auranofin = 1:3:10. The HPLC methods used were found suitable for isolation of Cd-MT in the HE100 cells, but not for the Au-MT in the HEAF cells. By HPLC, the Cd-MT in the HE100 cells was resolved into 3 MT-1 and 1 MT-2 iso-proteins exhibiting the amino acid composition typical of MT. Judged by HPLC, the MT in these cells constituted 0.4% of the cytosolic proteins.

Mediator and target cell variability in proliferative response of human adherent synovial cells in culture

The proliferation of cultures of adherent synovial cells was studied in response to mediators generated from several sources. Monocyte enriched cultures produced factors in the 70-80,000 and 12-16,000 molecular weight range. Both of these areas of activity also stimulate prostaglandin (PGE) from adherent synovial cells and have interleukin 1 (IL-1) activity. The 70-80,000 region appears to be the 12-16,000 molecular weight activity bound to serum components. When stimulated with the same concentration of a single preparation of this monocyte derived factor, cell lines showed great variability, with inhibition of proliferation in 2 cell lines and the remaining exhibiting stimulation. There was no correlation of proliferation with the PGE producing capacity of the cells. The proliferation response showed no correlation to PGE production by particular cell lines. Lymphocyte enriched cultures produced a factor of 36-40,000 daltons that stimulates adherent synovial cell proliferation but does not have PGE stimulating or IL-1 activity.

Mannose-specific binding sites in synoviocytes of rat synovial membrane: an ultrastructural-cytochemical study

Mannose-specific binding sites in the two types of synoviocytes (A and S) from the synovial membrane of normal rat knee joints were studied by an ultrastructural-cytochemical method using horseradish peroxidase (HRP) as a ligand. The A cells showed mannose-specific binding sites for HRP which were localized in coated pits and coated vesicles (110 nm) as well as in smooth-walled vesicles, vacuoles, and tubules. No mannose-specific binding sites for HRP were detected in the S cells. Together with previous observations on absorption of intraarticularly injected HRP in type A and type S synoviocytes, the present results strongly support the interpretation that the A cells internalize HRP by receptor-mediated endocytosis and that the S cells internalize HRP by fluid-phase endocytosis only. The present results agree with the suggestion that mannose-specific binding sites consist of two pools, the one concerned with internalization of ligand and the other with intracellular targeting of internalized ligand.

Innervation of synovial membrane and meniscus

Substance P-immunofluorescent nerves, which are closely connected to pain transmission, were shown in human knee synovial membrane and menisci. Both tissues also contained enkephalin-immunofluorescent nerves, which are probably involved in the modulation of pain transmission. Previous suggestions on the presence of nociceptive receptors in these non-cartilaginous joint structures, made on a histological basis, are thus confirmed by a specific immunohistochemical method.

[Localization of carbohydrate component in human synovial lining cells with fluorescent lectins and enzyme digestion]

FITC-conjugated lectins, Con-A, DBA, GS-I, GS-II, PNA, MPA, RCA-I, SBA, UEA-I, WGA were used for demonstration of lectin bindings of human synovial lining cells, obtained from the patients with rheumatoid arthritis (RA), osteoarthritis (OA), aseptic necrosis (AN), and traumatic injury (TI). In the RA samples, GS-I binding to the cytoplasmic sites was predominantly noted and moderate SBA and MPA bindings were observed. However, PNA was not significant. In the OA samples, predominant binding was found in GS-I and SBA lectins, moderate binding in MPA and PNA. In the AN samples, binding was predominant in MPA, moderate in GS-I, SBA and PNA. After neuraminidase treatment the intensity of fluorescence increased significantly with PNA and moderately with SBA in the RA samples. These results suggested that the inflammatory lining cells produce galactose group and the content of neuraminic acids in the synovial membranes of the RA appears to be greater than in those of other diseases.

Amyloid arthropathy in patients undergoing periodical haemodialysis for chronic renal failure: a new complication

Seven patients (five male and two female) with chronic renal failure (CRF) treated by periodical haemodialysis presented with swelling and effusion of more than three months' duration in knees (four bilateral), shoulders (two, one of them bilateral), elbow (one), and ankle (one). Four had a carpal tunnel syndrome both clinically and electromyographically (three bilateral). All patients had hyperparathyroidism secondary to their CRF, which was not due to amyloidosis in any of them. The dialysis duration period varied from five to 14 years, with an average of 8.6 years. Amyloid deposits (Congo red positive areas with green birefringence under polarising microscopy) were shown in six of the seven synovial biopsy specimens of the knee, in five of the sediments of the synovial fluids, and in specimens removed during carpal tunnel syndrome surgery. No amyloid was found in the biopsy specimen of abdominal fat of six of the patients. The finding of amyloid only in the synovial membrane and fluid, and carpal tunnel, its absence in abdominal fat, and the lack of other manifestations of generalised amyloidosis (cardiomyopathy, malabsorption syndrome, macroglossia, etc.) and of Bence Jones myeloma (protein immunoelectrophoresis normal) raises the possibility that this is a form of amyloidosis which is peculiar to CRF treated by periodical haemodialysis.

Amyloid arthropathy: characterization of the amyloid protein

An 82 year-old man was referred for joint pain and numbness of his hands. Physical examination revealed limitation of movement of the PIP's, MCP's, wrists, shoulders and knees. There was marked synovial thickening of the wrists and atrophy of the thenar muscles of both hands due to arpal tunnel syndrome. The patient was operated on both hands, the median nerves were released and a synovectomy of the wrist was performed. Two months later, a synovectomy of the right shoulder was performed. Histological examination of tissues from the wrists and shoulder demonstrated large deposits of amyloid in the synovia. Amyloid fibrils were extracted, solubilized in 6M and were fractionated on a Sepharose 6B. All three proteins that were purified from the amyloid fibrils proved to be derived from VkI light chain by their amino terminal sequences. This is the first amyloid protein to be characterized from amyloid arthropathy.

Clinicopathological importance of deposits of amyloid in the femoral head

The pattern of amyloid deposits in the femoral head is described in four cases, two of which had deposits of amyloid related to age and two of which had generalised systemic amyloidosis (one of primary amyloidosis, one of multiple myeloma). The deposition of amyloid in the articular cartilage of the femoral head was similar in all four cases. Heavy deposits of synovial amyloid were identified in the case with primary amyloidosis and in one of the cases with amyloidosis related to age. Both cases of generalised systemic amyloidosis showed abundant deposits of amyloid in the bone marrow. Amyloid was not present in the bone marrow of either case with amyloidosis related to age. The importance of these findings is discussed in relation to the pathogenesis of the arthropathy syndrome of a rheumatoid type described in cases of primary amyloidosis and multiple myeloma.

Release of interleukin-1 from human synovial tissue in vitro

During the enzymatic disaggregation of human synovium, used in the process of isolating synoviocytes, a factor was liberated into the culture medium that exhibited the thymocyte mitogenic properties of interleukin-1. Like interleukin-1, this synovial-derived mitogen could be isolated using an affinity column of antihuman leukocytic pyrogen. By gel filtration and isoelectric focusing, the mitogen cofractionated with human monocyte-derived interleukin-1. Finally, the isolated mitogen was shown to exhibit other properties of interleukin-1: stimulation of the secretion of interleukin-2, enhancement of the titer of acute-phase proteins in vivo, and stimulation of the release of prostaglandin E2 from human synoviocyte cultures. These observations suggest that interleukin-1 can be derived from the human synovium.

Mapping of proteins from cultured fibroblasts of synovial and subcutaneous origin by high resolution two-dimensional polyacrylamide gel electrophoresis

Nine different cell lines of human (A) rheumatoid and (B) normal synovial fibroblasts and of (C) normal skin fibroblasts were obtained from tissue explants and grown as monolayers. The cellular protein synthesis was studied by high resolution two-dimensional polyacrylamide gel electrophoresis. Between the fourth and 10th passage of the cells in culture apparently no consistent differences were found which could be ascribed to the origin of the cells, to the rheumatoid state of the synovial tissue, or to the increasing age of the cultured fibroblasts.

Identification of link proteins in canine synovial cell cultures and canine articular cartilage

Link proteins are glycoproteins in cartilage that are involved in the stabilization of aggregates of proteoglycans and hyaluronic acid. We have identified link proteins in synovial cell cultures form normal canine synovium using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunofluorescence, and immunolocation with specific antibodies by electrophoretic transfer. We have also found evidence for the synthesis of link proteins in these cultures by fluorography of radiolabeled synovial cell extracts. We have identified a 70,000 mol-wt protein in canine synovial cell culture extracts that has antigenic cross-reactivity with the 48,000-mol-wt link protein. Three link proteins were identified in normal canine articular cartilage. These results indicate that link proteins are more widely distributed in connective tissues than previously recognized and may have biological functions other than aggregate stabilization.

Immunohistochemical studies of interleukin-2 and gamma-interferon in rheumatoid arthritis

Synovial tissues were studied, using immunofluorescence techniques, for localization of lymphocytic infiltrates and immune reactants, including C3, C5b-9, C9, and Ia antigen. Tissue distribution of interleukin-2 (IL-2) and gamma-interferon was also determined, using mouse monoclonal antibodies. IL-2 was found in association with OKT8 and OKT4 T cells, and gamma-interferon was noted in association with T cells, B cells, and macrophages. Staining both for IL-2 and for gamma-interferon was surprisingly faint in view of the intensity of lymphocytic infiltration.

Histopathological and ultrastructural studies of synovium in Milwaukee shoulder syndrome--a basic calcium phosphate crystal arthropathy

Light and electron microscopic study of synovial specimens from four patients with the Milwaukee shoulder syndrome disclosed vascular congestion, villous and focal synovial lining cell hyperplasia, occasional giant cells, and fibrin deposition both within and on the surface of the synovium. Although these changes are non-specific, the finding of basic calcium phosphate crystal aggregates in all four cases and the near total absence of an inflammatory reaction are helpful in distinguishing this condition from other types of arthritis. The focal areas of synovial cell hyperplasia may relate to the powerful mitogenic effect of both synthetic and naturally occurring calcium-containing crystals in concentrations found in the synovial fluid of these patients.

The effect of synovial iron on the progression of rheumatoid disease. A histologic assessment of patients with early rheumatoid synovitis

Seventeen patients with early rheumatoid synovitis underwent synovial biopsy to assess the interrelationship between both ferritin (the intracellular iron storage protein) and Perls' positive iron (ferric iron in loose combination with protein), on the activity and course of rheumatoid disease. The amount of ferritin was associated to a significant degree with the activity of the disease at the time of biopsy, but showed no relation to the way the disease progressed over the following year. In contrast, the amount of Perls' iron bore no relation to the activity of the disease at biopsy, but its presence was associated with persistent disease. It is argued that this association is direct, that ferritin production may fail in a population of synovial macrophages, and that Perls' ferric iron may either be reduced to the ferrous form and promote the formation of toxic free radical species, or stimulate collagenase and prostaglandin release from synovial macrophages.

Surface membrane glycoproteins of macrophage-like synovial cells from rheumatoid and control patients

Synovial cells were prepared by enzyme digestion and Percoll gradient centrifugation of rheumatoid arthritis (RA) synovial specimens or by trypsin-rinsing of non-inflammatory cadaver joints. Most (70-80%) of the cells from RA patients were OKIa -positive macrophage-like cells, 10-20% other OKIa -positive cells, and about 10% fibroblastic cells, whereas 90% of the normal synovial cells were OKIa -positive macrophage-like cells and the rest fibroblasts. These adherent synovial cells were compared with fibroblastic synovial cells obtained by sequential passaging of explanted dividing cells. Periodate-[3H]borohydride labelling followed by SDS-gradient gel electrophoresis demonstrated similar sialo-glycoprotein patterns in both the adherent synovial cells and synovial fibroblasts. The molecular weights of the main surface glycoproteins resembled closely those of skin fibroblasts but not those of peripheral blood monocytes. RA samples showed inconsistent heterogeneity. The results indicate either that all synovial cells possess a similar basic structure or that macrophages of peripheral blood origin express fibroblastic contact glycoproteins when settling down into synovium.

Aluminum in the joint tissues of chronic renal failure patients treated with regular hemodialysis and aluminum compounds

We studied the concentrations of aluminum in the articular tissues of 5 hemodialysed patients treated with aluminum compounds. Aluminum crosses the synovial barrier, is found in synovial fluid (SF) and accumulates in the joint structures (synovial membrane and joint cartilage). The concentrations found in synovial tissue were 2.7 to 10 times control values, in SF 2.5 to 8 times the control concentrations and in cartilage 2.6 times the control concentrations. Transmission electron microscopy showed localization of aluminum in the lysosomal structures and wavelength dispersive microprobe analysis showed aluminum in cellular components associated with phosphate. The possible toxicity of aluminum to joints merits further investigations.

Lipid peroxides in human articular cartilage

The hypothesis that increased generation of lipid peroxides (LP) causes articular cartilage damage in older patients and in those with osteoarthritis was tested by directly measuring LP tissue levels in various layers of human articular cartilage. The LP content was significantly greater in the superficial than in the deeper portion of the cartilage, but lower in cartilage than in liver, kidney, adrenal glands and synovium. When LP were related to the total lipid content of these tissues, a high peroxide per lipid ratio was obtained for articular cartilage. The relevance of these findings to the mechanism of cartilage fibrillation is discussed.

Sequential appearance of fibronectin and collagen fibres in experimental arthritis in rabbits

The sequential changes in the presence of fibronectin in the synovial membrane during the development of antigen-induced arthritis in rabbits were studied using an indirect immunoperoxidase technique on the tissue specimens fixed in formaldehyde, embedded in paraffin and pre-treated with pepsin and testicular hyaluronidase. The relation to the distribution of fibronectin and connective tissue fibres, demonstrated as either argyrophilic or red by van Gieson method, was studied. Initial after the induction of the arthritis the synoviocytes became increased in size and number. The subsynoviocytial tissue was invaded by granulocytes and the number of vessels was increased. Fibronectin in increased amount was seen around the lining cells. After 2-4 weeks a markedly reduced amount of granulocytes were seen together with an increase in the number of macrophages. At this stage, fibronectin was also found together with argyrophilic fibres in the subsynoviocytial connective tissue. After 8-13 weeks the synovial membrane was found hypertrophic and folded. The lining layer was unchanged, but in the subsynoviocytial tissue lymphocytes and plasma cells were more focally arranged. At that time fine fibres, stained by the van Gieson method, were present together with fibronectin and argyrophilic fibres in the subsynoviocytial tissue. The morphological change and the distribution of fibronectin in experimentally induced arthritis correlated temporally to the morphological change and the presence of fibronectin found in experimentally induced granulation tissue.