Mechanisms of alpha 1-antitrypsin inactivation in arthritic joints: comment on the article by Abbink et al.
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Arthritis, Rheumatoid↗
Biomedical subjects
D R Blake
Publications and source records attributed to D R Blake.
Relationship between alpha 1-antitrypsin inactivation and tumor necrosis factor alpha concentration in the synovial fluid of patients with rheumatoid arthritis.
OBJECTIVE: To examine the relationship between alpha 1-antitrypsin (alpha 1AT) specific activity and tumor necrosis factor alpha (TNF alpha) concentration in synovial fluid from 48 patients with rheumatoid arthritis. METHODS: The specific activity of alpha 1AT was calculated from the measurement of alpha 1AT concentration (by rocket immunoelectrophoresis) and elastase inhibitory capacity. TNF alpha was detected by enzyme-linked immunosorbent assay. RESULTS: TNF alpha concentrations correlated with the extent of alpha 1AT inactivation. CONCLUSION: Our findings are consistent with a role of elastase in TNF alpha release within the inflamed joint.
Arthritis, Rheumatoid↗
Syphilitic placentitis: an immunopathy.
The placentas of eight infants with congenital syphilis were examined by both immunohistochemical and immunofluorescent techniques. Significant IgM, C3 and rheumatoid factor reactivity were observed in all the syphilitic placentas. We postulate that their presence plays an important role in the evolution of the pathological changes.
Antigen-Antibody Complex↗
Circulating IgA antibody against a 65 kDa heat shock protein in acute alcoholic hepatitis.
Heat shock proteins are known to be immunogenic in a number of diverse conditions and can be induced by hypoxia, tumour necrosis factor and alcohol--all potential triggers in patients with acute alcoholic hepatitis. In the present study, sera from 23 patients with acute alcoholic hepatitis, 18 liver disease controls, ten patients with inactive alcoholic liver disease and six alcoholics without liver damage were screened for the antibody to a 65 kDa heat shock protein using an ELISA technique. IgA antibody was found to be closely associated with alcoholic hepatitis; 20/23 patients were seropositive compared to 5/18 liver disease controls and 4/10 with inactive alcoholic cirrhosis. IgM and IgG antibodies to the 65 kDa heat shock protein were less closely associated with alcoholic hepatitis and were positive in nine and eight of the 23 patients, respectively, compared with six and seven of 18 liver disease controls. Neither antibody was detected in alcoholics without liver damage or normal controls. These data indicate that an IgA immune mediated response to the 65 kDa heat shock protein is characteristic of patients with acute alcoholic hepatitis and may be one mechanism underlying observed persistence of liver damage after cessation of alcohol consumption.
Acute Disease↗
AT1 receptor characteristics of angiotensin analogue binding in human synovium.
1. Angiotensin II (AII) reduces blood flow, modulates vascular remodelling and is a growth factor. Human inflammatory arthritides are characterized by synovial hypoperfusion, hypoxia and proliferation. We aimed to localize and characterize receptors for AII in human synovium. 2. We used quantitative in vitro receptor autoradiography with [125I]-(Sar1, Ile8)AII and [125I]-AII on human synovium from patients with chondromalacia patellae, osteoarthritis and rheumatoid arthritis. 3. [125I]-(Sar1, Ile8)AII and [125I]-AII bound to similar sites on synovial blood vessels, lining cells and stroma. Binding to microvessels (< 100 microns diameter) was more dense than to arteriolar media, and vascular binding was more dense than that to lining cells and stroma. 4. Microvessels and arterioles which displayed angiotensin converting enzyme-like immunoreactivity also displayed specific binding of [125I]-(Sar1, Ile8)AII. 5. Specific binding of [125I]-(Sar1, Ile8)AII to each structure was completely inhibited by 10 microM dithiothreitol and was inhibited by unlabelled ligands with the rank order of potency (Sar1, Ile8)AII > AII > losartan = SKF108566 > PD123319 indicating an AT1 subclass of angiotensin receptor. 6. GTP gamma S (1 microM) abolished specific binding of [125I]-AII and abolished the high affinity component of the binding inhibition curve for AII against [125I]-(Sar1, Ile8)AII, indicating G protein coupling. 7. The distribution of [125I]-(Sar1, Ile8)AII binding sites was similar in all disease groups and no significant differences in binding densities, affinities or specificities were observed between disease groups. 8. Locally generated AII may act on synovial AT1 receptors to modulate synovial perfusion and growth. Specific AT1 receptor antagonists should help elucidate the role of angiotensins in human arthritis.
Adult↗
The role of bradykinin B1 receptors in the maintenance of intra-articular plasma extravasation in chronic antigen-induced arthritis.
1. The role of bradykinin B1 and B2 receptors in bradykinin- and des-Arg9-bradykinin-induced plasma extravasation in normal and inflamed rat knee joints was investigated by use of an antigen-induced model of chronic arthritis. A modification of an Evans blue extraction technique allowed the unstimulated (basal) plasma extravasation to be assessed in this model. The contributions of bradykinin B1 and B2 receptors towards basal synovial plasma extravasation were determined. 2. In normal knees, intra-articular injection of bradykinin (BK) induced plasma extravasation in a potent, dose-dependent manner with a threshold of 0.01 nmol and an ED50 of 0.1 nmol. In day 5 arthritic knees, basal plasma extravasation was substantially enhanced. Lower doses of BK had no demonstrable effect and increases above basal extravasation were first observed at 0.1 nmol. Thereafter the dose-response mirrored the response in normal knees and the maximal response was unaltered. 3. The B1 agonist, des-Arg9-BK, induced slight but significant plasma extravasation in normal knees but was less potent than bradykinin. This response was inhibited by the B1 receptor antagonist, des-Arg9, [Leu8]-BK. Lower doses of des-Arg9-BK bradykinin did not significantly increase basal extravasation in day 5 arthritic knees but, in contrast to BK, the maximal response was significantly enhanced. 4. The B2 antagonist, Hoe 140, inhibited BK-induced plasma extravasation in normal joints over a dose-range of 0.1-1.0 nmol but was relatively inactive in day 5 inflamed knees. The B1 receptor antagonist, des-Arg9, [Leu8]-BK, was relatively inactive in normal joints but showed increased potency against BK-induced plasma extravasation in day 5 arthritic joints.5. Hoe 140 and des-Arg9,[Leu8]-BK both inhibited basal extravasation in arthritic joints on days 1 and 5 post-challenge in a dose-dependent fashion. Whilst Hoe 140 was the more potent inhibitor on day 1, it was less potent than des-Arg9,[Leu8]-BK on day 5.6. Although the majority of responses to BK in normal tissue are mediated via B2 receptors, a small population of B1 receptors may exist in normal joint tissues. The data presented in this study suggest an evolving role for B1 receptors in the mediation of plasma extravasation in inflamed joint tissues. A role for BK antagonists in the treatment of arthritis is also suggested.
Animals↗
Thrombin in inflammation and healing: relevance to rheumatoid arthritis.
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Arthritis, Rheumatoid↗
Arthritogenic potential of the 65 kDa stress protein--an experimental model.
OBJECTIVES: To assess the effect of an intra-articular presentation of stress (heat shock) proteins (hsp) on joint inflammation. METHODS: Wistar rats were sensitised with a suspension of heat killed Mycobacterium tuberculosis in oil in the scruff of the neck and challenged intra-articularly with stress protein or M tuberculosis preparations. Inflammation was assessed by joint swelling and, using immunohistology, cellular infiltration of the synovium and antibody induction by an enzyme-linked immunosorbent method. RESULTS: It was shown, for the first time, that the intra-articular administration of a recombinant myobacterial 65 kDa hsp can induce joint inflammation in M tuberculosis sensitised recipients; both powdered M tuberculosis and the purified protein derivative of tuberculin (PPD) produced a similar response, with T cell infiltration of the synovium and a time course typical of delayed type hypersensitivity. This response was specific to the 65 kDa protein as another immunodominant mycobacterial stress protein of 10 kDa was ineffective. Furthermore, intra-articular injection of the 65 kDa hsp induced an antibody response against both the 65 kDa and 10 kDa proteins and the antibody titres continued to rise when knee swelling had subsided. CONCLUSIONS: These results support the hypothesis that 60 kDa proteins are a relevant arthritogenic stimulus in an M tuberculosis background. Moreover, when antigen presentation occurs in the synovium of previously sensitised individuals, circulating antibodies are generated which persist and recognise cross-reactive epitopes on several stress proteins.
Animals↗
Effect of three animal models of inflammation on nerve fibres in the synovium.
OBJECTIVES: Both sensory and sympathetic nerve fibres are depleted in the synovium in rheumatoid arthritis (RA). The hypothesis that the induction of an inflammatory response in the synovium is capable of causing depletion of nerve fibres was tested. METHODS: To investigate this phenomenon experimental arthritis in the rat was induced by three different methods and the synovium was examined for evidence of nerve depletion by immunocytochemistry. RESULTS: In a synovitis induced by latex spheres, a mainly macrophage foreign body type reaction, no nerve depletion was seen. In contrast both in an antigen-induced and a hydrogen peroxide-induced model of arthritis nerve fibre depletion was observed. This appeared to affect sensory and sympathetic nerve fibres equally. Nerve fibre depletion was only seen in areas of inflammatory cell infiltration indicating that a mixed lymphocyte and macrophage population of cells may be necessary for this effect. CONCLUSIONS: An inflammatory response, containing lymphocytes and macrophages, in the synovium is capable of the depletion of the finely myelinated and unmyelinated neuropeptide-containing nerves.
Animals↗
Intra-articular injections of 750 kD hyaluronan in the treatment of osteoarthritis: a randomised single centre double-blind placebo-controlled trial of 91 patients demonstrating lack of efficacy.
OBJECTIVE: To determine the safety and efficacy of intra-articular injections of hyaluronan in the treatment of osteoarthritis of the knee. METHODS: A randomised double-blind placebo-controlled trial was carried out on 91 patients with radiologically confirmed osteoarthritis of the knee who were recruited from the outpatient clinics. RESULTS: It was found that weekly intraarticular injections of 20 mg of hyaluronan of M(r) = 750,000 (Hyalgan) in 2 ml of buffered saline performed no better than the inert vehicle alone over a five week period. The principal side effects of a transient increase in pain and swelling in the affected knee was observed in 47% of the treatment group compared with 22% of the placebo group. A few patients with radiologically mild disease treated with Hyalgan appeared to experience medium to long-term symptomatic improvement over matched placebo controls as judged by a delayed return to previous NSAID therapy or analgesia other than paracetamol. Patient numbers in the survival groups, however, were too small to be meaningful. CONCLUSION: It is concluded that intraarticular administration of this preparation of 750 kD hyaluronan offers no significant benefit over placebo during a five week treatment period, but incurs a significantly higher morbidity, and therefore has no place in the routine treatment of osteoarthritis.
Acetaminophen↗
Helicobacter pylori stimulates antral mucosal reactive oxygen metabolite production in vivo.
To determine if reactive oxygen metabolites have a pathogenic role in Helicobacter pylori (H pylori) related gastroduodenal disease, this study measured their production in antral mucosal biopsy specimens. Two related chemiluminescence techniques were used comparing H pylori positive (n = 105) and negative patients (n = 64) with a similar spectrum of macroscopic disease. After chemiluminescence assays, biopsy specimens were graded histologically. Increased luminol dependent chemiluminescence (detecting reactive oxygen metabolites through peroxidase catalysed reactions) was found in H pylori positive patients (median photon emission = 6.4 x 10(3)/min/mg wet weight (95% confidence intervals 3.6 to 9.9)) but not H pylori negative cases (-0.9 (-1.3 to -0.6)) (p = 0.0001). Similar results were found using lucigenin (which reacts directly with oxygen metabolites, particularly superoxide): (H pylori positive 0.9 (0.1 to 3.2); H pylori negative -1.2 (-3.4 to -0.6)) (p = 0.0003). Chemiluminescence was greater in H pylori positive compared with negative tissue when samples were grouped by equivalent macroscopic or microscopic damage. This difference was in part accounted for by a greater neutrophil infiltration in the H pylori positive mucosa, but when biopsy specimens with equivalent neutrophil infiltration could be compared directly, positive specimens gave greater chemiluminescence than negative. Smoking, drugs, and alcohol consumption had no independent effect. It is concluded that excess mucosal reactive oxygen metabolite production is associated with H pylori gastric antral infection and may be an important pathogenic mechanism. There is no evidence for reactive oxygen metabolite participation in the pathogenesis of gastric mucosal injury in cases unrelated to H pylori infection.
Antioxidants↗
Proinflammatory effects of morphine in the rat adjuvant arthritis model.
Morphine has been shown to alter various aspects of the immune response. We examined its effect on progression of the T-cell-mediated model, rat adjuvant arthritis. Saline, morphine or the opioid antagonist naloxone were administered to male Wistar rats via subcutaneous osmotic pumps implanted three days prior to adjuvant disease induction by an intra-dermal injection of Mycobacterium tuberculosis in oil. The time of disease onset was found to be accelerated (day 11) for the morphine group as compared to the saline control (day 13). In addition morphine produced a significant increase in paw swelling (days 13 and 14), bone demineralization and bone erosions. A significant decrease in body weight as compared to the saline control was also observed. Naloxone had no significant effect on the degree of the inflammation seen, although like morphine it significantly increased bone demineralization and bone erosions as assessed by radiography.
Animals↗
A comparative evaluation of the metabolic profiles of normal and inflammatory knee-joint synovial fluids by high resolution proton NMR spectroscopy.
High resolution 1H NMR spectroscopy has been employed to investigate the metabolic profile of healthy human knee-joint synovial fluid (SF) and the biochemical data acquired have been compared with those of matched serum, and inflammatory knee-joint SF samples. Results obtained indicate that the healthy human knee-joint has a hypoxic status (high lactate level when expressed relative to that of paired serum) that is milder than that of the inflamed human knee-joint. Moreover, normal SF differs from that of inflammatory SF in that it contains little or no NMR-detectable lipoprotein-associated fatty acids and 'acute-phase' glycoproteins, an observation reflecting the limited passage of these macromolecules from plasma into the synovial space in healthy subjects.
Acute-Phase Proteins↗
High resolution proton NMR investigations of rat blood plasma. Assignment of resonances for the molecularly mobile carbohydrate side-chains of 'acute-phase' glycoproteins.
An intense broad resonance at 2.14 ppm present in high field (400, 500 and 600 MHz) Hahn spin-echo 1H-NMR spectra of rat blood plasma, but absent from those of human blood plasma is attributable to the presence of terminal O-acetylsialate sugars in the molecularly mobile carbohydrate side-chains of 'acute-phase' glycoproteins (predominantly alpha 1-acid glycoprotein). The presence of such alternative acetylsugars in the carbohydrate side-chains of rat plasma glycoproteins are of much physiological and experimental significance in view of the regular use of these animals in model systems of human inflammatory conditions.
Acute-Phase Proteins↗
Inactivation of synovial fluid alpha 1-antitrypsin by exercise of the inflamed rheumatoid joint.
alpha 1-Antitrypsin (alpha 1AT) is known to be oxidised by reactive oxygen species both in vitro and in vivo, leading to its inactivation. We report here that synovial fluid (SF) alpha 1AT is inactivated during exercise of the knee-joints of rheumatoid arthritis (RA) patients. Sequential SF sampling from exercised RA patients showed a marked decrease in the mean activity of alpha 1AT after exercise with no change in the molecular forms of alpha 1AT. No such inactivation was found in the control (continuously resting) RA patients. We suggest that oxidation may contribute to alpha 1AT inactivation as a consequence of 'hypoxic-reperfusion' injury after exercise of the inflamed joint.
Adult↗
An investigation of the abnormal metabolic status of synovial fluid from patients with rheumatoid arthritis by high field proton nuclear magnetic resonance spectroscopy.
The 1H Hahn spin-echo NMR profiles of rheumatoid synovial fluids have been investigated and compared with those of matched serum samples. In addition to markedly elevated lactate and diminished glucose concentrations, inflammatory synovial fluids contained (i) substantially lower levels of NMR-detectable chylomicron-and very-low-density-lipoprotein-associated triacylglycerols which appear to have a shortened mean chain-length, and (ii) high concentrations of ketone bodies (predominantly 3-D-hydroxybutyrate), relative to those of corresponding paired serum samples. These observations confirm the abnormal metabolic status of the inflamed rheumatoid joint and provide evidence for an increased utilisation of lipids for fuel therein.
3-Hydroxybutyric Acid↗
Stress proteins in colorectal mucosa. Enhanced expression in ulcerative colitis.
Stress (heat shock) proteins are ubiquitous intracellular proteins that can be induced in vitro by physiological stress events that occur during inflammation. We have used an indirect immunoperoxidase method to locate 60-kDa stress proteins in biopsies taken from normal and inflamed colorectal mucosa. An anti-60-kDa monoclonal antibody (ML30) produced specific staining of surface epithelial cells localized to the site of the Golgi apparatus. In ulcerative colitis, there was an increased concentration of this stress protein compared with controls (P < or = 0.002) and also with a small group of active Crohn's colitis (P < or = 0.01), but no relationship between its concentration and disease activity. All biopsies also showed staining of goblet cells by ML30, suggesting a possible cross-reaction with mucin; electroblotting of crude but not purified mucin showed a faint 60-kDa band with ML30. We conclude that the 60-kDa stress protein is present in normal colorectal epithelial cells and is markedly induced in vivo in ulcerative colitis. Further, we suggest that since the 60-kDa protein functions as a molecular chaperone, it may associate with colonic mucin aiding in its synthesis and/or secretion.
Adult↗
Anti-endothelial cell antibodies in inflammatory bowel disease.
Antibodies to endothelial cells may be involved in the pathogenesis of vasculitic disorders. In view of recent evidence implicating intestinal vascular injury in the pathogenesis of inflammatory bowel disease, we have sought anti-endothelial cell antibodies in affected patients, examined their relationship to vascular injury, and tested their ability to mediate endothelial cell cytotoxicity in vitro. Anti-endothelial cell antibody levels were elevated in ulcerative colitis (P < 0.0001) and Crohn's disease (P < 0.05) compared with healthy controls. In ulcerative colitis, anti-endothelial cell antibody levels were related to disease activity and correlated with circulating levels of von Willebrand factor (r = 0.58, P < 0.01), a marker of vascular injury. Anti-endothelial cell antibodies, however, were not directly cytotoxic to endothelial cells in vitro. These data indicate, for the first time, an association between anti-endothelial cell antibody levels and vascular injury in vivo and suggest that they may be important in the pathogenesis of inflammatory bowel disease, particularly ulcerative colitis.
Antibodies, Antineutrophil Cytoplasmic↗