Arthropathy in hereditary haemochromatosis segregates with elevated erythrocyte mean corpuscular volume.

Objective: To evaluate the relationship between erythrocyte parameters and the presence or absence of arthritis in HFE C282Y homozygous hereditary haemochromatosis (HH) subjects compared to control groups of non-HH subjects with arthritis.Method: Erythrocyte and arthritis parameters [mean corpuscular volume (MCV) and mean cell haemoglobin (MCH)] were obtained from consecutive HH subjects (n = 119) who were referred for initial evaluation and management. For comparison, MCV and MCH values were collected from randomly selected non-HH subjects with rheumatoid arthritis (n = 100) and osteoarthritis (n = 100), consisting of equal numbers of men and women. Two other comparison groups comprised 16 men and women who were heterozygous for C282Y with arthritis, and 38 non-HH subjects with type 2 polyarticular osteoarthritis (T2POA).Results: MCV values were significantly higher in HH subjects with arthritis (95 ± 0.56 fL) than in HH subjects without arthritis (92.75 ± 0.50 fL, p = 0.037). HH subjects with or without arthritis demonstrated a higher mean MCV than the control groups of non-HH osteoarthritis (90.12 ± 0.46 fL, p < 0.001) and non-HH rheumatoid arthritis (90.94 ± 0.57 fL, p < 0.001). HH subjects with arthritis also demonstrated a higher MCV than heterozygous C282Y subjects with arthritis (93.18 ± 1.55 fL, p = 0.025) and non-HH subjects with a similar pattern of arthritis, notably T2POA (91.13 ± 0.50 fL, p < 0.01). An MCV of ≥ 97.85 fL provided a likelihood ratio of 2.2 for development of arthritis in HH subjects.Conclusion: This study demonstrated a relationship between elevated MCV and arthritis in incident cases of HH.

K/B×N serum transfer arthritis is delayed and less severe in leukaemia inhibitory factor (LIF)-deficient mice.

This study is investigating the role of leukaemia inhibitory factor (LIF) in the development of inflammation and joint damage in the mouse K/B×N serum transfer arthritis model. LIF knock-out (LIF(-/-)) mice were generated by mating heterozygote females (LIF(+/-)) with heterozygote males. Arthritis was induced in 8-20-week-old LIF knock-out mice (LIF(-/-)) by intraperitoneal injection of pooled K/B×N sera (50 µl) on days 0 and 2. Clinical disease was scored daily for 6 days. Safranin-O and haematoxylin-stained sections were scored for synovitis, joint space exudate, cartilage degradation and bone damage. RNA was extracted from ankle joints and used to investigate gene expression levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1, LIF, LIF receptor, oncostatin M (OSM), OSM receptor, IL-6 and their common receptor subunit gp130 by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results show that wild-type mice developed severe clinically overt polyarthritis. In contrast, LIF(-/-) mice showed a more than 50% reduction in clinical arthritis severity. Significantly lower histological scores were observed in LIF(-/-) mice compared to wild-type disease controls. LIF(-/-) mice had histopathological scores that were similar to normal healthy mice. IL-6 subfamily cytokine and receptor subunit expression remained unchanged. The expression levels for IL-6 were reduced significantly in all the diseased mice, whether wild-type or LIF(-/-) mice (P < 0·001), compared to healthy wild-type mice. We conclude that LIF contributes to the development of disease in the K/B×N serum transfer model of arthritis. These results provide further evidence for the role of LIF in inflammation and cartilage bone resorption and provide impetus to test the effects of LIF blockade as a therapeutic strategy in rheumatoid arthritis.

Hereditary hemochromatosis is characterized by a clinically definable arthropathy that correlates with iron load.

OBJECTIVE: To determine the frequency and character of arthropathy in hereditary hemochromatosis (HH) and to investigate the relationship between this arthropathy, nodal interphalangeal osteoarthritis, and iron load. METHODS: Participants were recruited from the community by newspaper advertisement and assigned to diagnostic confidence categories for HH (definite/probable or possible/unlikely). Arthropathy was determined by use of a predetermined clinical protocol, radiographs of the hands of all participants, and radiographs of other joints in which clinical criteria were met. RESULTS: An arthropathy considered typical for HH, involving metacarpophalangeal joints 2-5 and bilateral specified large joints, was observed in 10 of 41 patients with definite or probable HH (24%), all of whom were homozygous for the C282Y mutation in the HFE gene, while only 2 of 62 patients with possible/unlikely HH had such an arthropathy (P=0.0024). Arthropathy in definite/probable HH was more common with increasing age and was associated with ferritin concentrations>1,000 µg/liter at the time of diagnosis (odds ratio 14.0 [95% confidence interval 1.30-150.89], P=0.03). A trend toward more episodes requiring phlebotomy was also observed among those with arthropathy, but this was not statistically significant (odds ratio 1.03 [95% confidence interval 0.99-1.06], P=0.097). There was no significant association between arthropathy in definite/probable HH and a history of intensive physical labor (P=0.12). CONCLUSION: An arthropathy consistent with that commonly attributed to HH was found to occur in 24% of patients with definite/probable HH. The association observed between this arthropathy, homozygosity for C282Y, and serum ferritin concentrations at the time of diagnosis suggests that iron load is likely to be a major determinant of arthropathy in HH and to be more important than occupational factors.

Ferritin concentrations in synovial fluid are higher in osteoarthritis patients with HFE gene mutations (C282Y or H63D).

OBJECTIVES: In view of the clinical similarities between polyarticular osteoarthritis (POA) with metacarpophalangeal (MCP) joint involvement and the arthropathy that occurs in hereditary haemochromatosis (HH), it was hypothesized that osteochondral damage in both disorders may be due to localized iron overload. Accordingly, it was predicted that the concentration of ferritin in synovial fluid (SF) would be higher in OA patients with HFE gene mutations than in HFE wild-type (wt) OA patients. The aim of this study was to test this proposition. METHODS: Sequential patients with physician-diagnosed OA and, for comparison, diverse inflammatory diseases of the joints, who required diagnostic or therapeutic arthrocentesis, were studied. Participants underwent HFE genotyping. SF samples were assayed for ferritin and also for selected cytokines and matrix metalloproteinases (MMPs). RESULTS: Seventy-three patients with diverse rheumatic disorders were recruited. Of the 29 patients who had knee OA, 15 were wt and 14 were heterozygous for HFE mutations (C282Y or H63D). Mean SF ferritin concentrations in the wt and heterozygous OA groups were 273 and 655 ng/mL, respectively (p = 0.0146). CONCLUSIONS: A predicted difference in SF ferritin concentrations in patients with knee OA was confirmed. Concentrations of ferritin in the SF were found to be two- to threefold higher in knee OA patients with HFE gene mutations compared to wt patients. This finding is consistent with the possibility that, in OA patients with HFE gene mutations, localized iron overload may contribute either directly or indirectly to osteochondral damage, possibly in a similar way to that which occurs in the arthropathy that complicates HH.

Confirmation of two major polyarticular osteoarthritis (POA) phenotypes--differentiation on the basis of joint topography.

OBJECTIVES: Previous studies of patients with primary hand and ankle osteoarthritis (OA) have suggested the presence of two major polyarticular OA (POA) phenotypes, designated Type 1 and Type 2. The former, characterised by sentinel distal interphalangeal (IP) (DIP) or proximal IP (PIP) joint OA resembles generalised OA (GOA), whereas the latter characterised by sentinel metacarpophalangeal (MCP)2,3 OA, resembles the arthropathy associated with hereditary haemochromatosis (HH). The aim of this study was to validate these putative phenotypes and to further investigate their clinical and genetic characteristics. METHODS: Newly referred patients had X-rays if pre-determined clinical criteria for OA in hand and other joints were met. Subjects were assigned to the putative Type 1 POA (T1POA) or Type 2 POA (T2POA) phenotypes if radiological criteria were satisfied. Human haemochromatosis (HFE) gene mutations were determined in buffy-coat DNA by polymerase chain reaction amplification, followed by restriction enzyme cleavage and analysis on a 3% agarose gel. The significance of differences was determined by Chi-square test or by Fisher's exact test. RESULTS: Sixty-seven patients fulfilled criteria for inclusion in this study; 39 (6M, 33F) for T1POA and 28 (18M, 10F) for T2POA. A statistically significant difference in gender was observed (64% male in the T2POA subset, P<0.0001). Heberden's nodes (HNs) were found in 34 of the 39 Type 1 subjects, but in only nine of the 28 Type 2 subjects (P<0.0001). HFE gene mutations were found in nine of the 39 Type 1 subjects (23%), whereas 21 of the 28 Type 2 subjects had a single HFE gene mutation (75%, P<0.0001). CONCLUSIONS: These findings confirm the hitherto hypothetical proposition of a T1POA phenotype conforming to nodal GOA (NGOA) and a T2POA phenotype closely resembling the arthropathy described in haemochromatosis (HH).

Identification of vigilance lapses using EEG/EOG by expert human raters.

It is critically important for certain occupational groups to remain highly alert throughout their working day. For safety reasons, it would be useful to automatically detect lapses in performance using EEG/EOG. Automating the detection process could be simplified considerably if we could mimic human experts. Surprisingly, it is unclear to what extent human EEG raters are able to detect lapses. Consequently, we undertook a study in which 4 expert EEG raters assessed the level of alertness of 10 air traffic controllers by observing a combination of their EEG and EOG while they performed a 10 min psychomotor vigilance task (PVT). They were specifically required to identify lapses or sleep episodes that might lead to a lapse in PVT performance. A reaction time .. 500 ms was defined as a PVT lapse. There was a total of 101 lapses (mean duration = 1.00 s). Of these, only 6 lapses were detected by one or more raters and all of these were marked as ;sleep'. Overall the human expert raters were unable to reliably identify lapses based only on EEG and EOG. This poor performance suggests an automated system would need to identify subtle features not overtly visible in the EEG.

Real-time detection of epileptiform activity in the EEG: a blinded clinical trial.

The aim of this study was to determine the performance of a PC-based system for real-time detection and topographical mapping of epileptiform activity (EA) in the EEG during routine clinical recordings. The system incorporates a mimetic stage to locate candidate spikes (including sharp-waves) followed by two expert-system-based stages, which utilize spatial and wide-temporal contextual information in deciding whether candidate events are epileptiform or not. The data comprised 521 consecutive routine clinical EEG recordings (173 hours). Performance was evaluated by comparison with three independent electroencephalographers (EEGers-I). A second group of two EEGers (EEGers-II) separately interpreted the spike topographical maps and, for EEGs categorized as containing only questionable EA by the detection system, reviewed 6 sec segments of raw EEG centered on each questionable event. Thirty-eight of the EEGs were considered to contain definite EA by at least two of EEGers-I. The false detection rate of the system was 0.41 per hour. The system was found to have a sensitivity of 76% and a selectivity of 41% for EEGs containing definite EA. However, it only missed detection of EA in 5% of the recordings. EEGers-II agreed with EEGers-I on the distribution (generalized, lateralized, focal, multifocal) of EA in 79% of cases. This is by far the largest clinical evaluation of computerized spike detection reported in the literature and the only one to apply this in routine clinical recordings. The false detection rate is the lowest ever reported, suggesting that this multi-stage rule-based system is a powerful and practical tool in clinical electroencephalography and long-term EEG monitoring.

Rheumatoid synovial fluid contains bioactive leukemia inhibitory factor with cartilage degrading activity--another target for chondroprotective intervention.

OBJECTIVE: To determine if the procatabolic activity of inflammatory synovial fluids (SF) from patients with rheumatoid arthritis (RA) could be attenuated by the cytokine antagonists murine leukemia inhibitory factor (LIF) binding protein (mLBP) and interleukin 1 receptor antagonist (IL-1ra). METHODS: Pig articular cartilage explants were cultured in the presence of either 20% v/v rheumatoid (RA) or osteoarthritic (OA) SF and varying concentrations of either mLBP and/or IL-1ra. The catabolic activity of the SF and the relative effects of mLBP and/or IL-1ra were assessed by determining the percentage release of sulfated glycosaminoglycans from cartilage explants. LIF concentrations were measured by ELISA. RESULTS: RA SF but not OA SF stimulated release of proteoglycans from pig cartilage explants in vitro (47.3 +/- 2.2% vs 24.6 +/- 2.0%; p < 0.0001). Murine LBP at 100 ng/ml and recombinant human (rh) IL-1ra at 5000 ng/ml produced a dose dependent inhibition of this proteoglycan release (p < 0.0067 and p < 0.0111, respectively). The RA SF stimulated proteoglycan release was attenuated by mLBP and rhIL-1ra independently. No additive effect of this attenuation was observed when maximal inhibitory doses were used in combination. The decrease in proteoglycan release produced by mLBP correlated significantly with LIF concentrations in RA SF. CONCLUSION: These findings are consistent with the concept that IL-1 stimulates cartilage proteoglycan resorption in RA. They also support the hypothesis that LIF, too, contributes to cartilage proteoglycan resorption in RA. The residual stimulation not accounted for by IL-1 or LIF suggests other cytokines may contribute. The role of LIF and related or unrelated cytokines may need to be taken into account to optimize chondroprotection in RA and other rheumatic diseases.

Enhancement of deep epileptiform activity in the EEG via 3-D adaptive spatial filtering.

The detection of epileptiform discharges (ED's) in the electroencephalogram (EEG) is an important component in the diagnosis of epilepsy. However, when the epileptogenic source is located deep in the brain, the ED's at the scalp are often masked by more superficial, higher-amplitude EEG activity. A noninvasive technique which uses an adaptive "beamformer" spatial filter has been investigated for the enhancement of signals from deep sources in the brain suspected of containing ED's. A forward three-layer spherical model was used to relate a dipolar source to recorded signals to determine the beamformer's spatial response constraints. The beamformer adapts, using the least-mean-squares (LMS) algorithm, to reduce signals from sources distant to some arbitrarily defined location in the brain. The beamformer produces three outputs, being the orthogonal components of the signal estimated to have arisen at or near the assumed location. Simulations were performed by using the same forward model to superimpose realistic ED's on normal EEG recordings. The simulations show the beamformer's ability to enhance signals emanating from deep foci by way of an enhancement ratio (ER), being the improvement in signal-to-noise ratio (SNR) to that observed at any of the scalp electrodes. The performance of the beamformer has been evaluated for 1) the number of scalp electrodes, 2) the recording montage, 3) dependence on the background EEG, 4) dependence on magnitude, depth, and orientation of epileptogenic focus, and 5) sensitivity to inaccuracies in the estimated location of the focus. Results from the simulations show the beamformer's performance to be dependent on the number of electrodes and moderately sensitive to variations in the EEG background. Conversely, its performance appears to be largely independent of the amplitude and morphology of the ED. The dependence studies indicated that the beamformer's performance was moderately dependent on eccentricity with the ER increasing as the dipolar source and the beamformer were moved from the center to the surface of the brain (1.51-2.26 for radial dipoles and 1.17-2.69 for tangential dipoles). The beamformer was also moderately dependent on variations in polar or azimuthal angle for radial and tangential dipoles. Higher ER's tended to be seen for locations between electrode sites. The beamformer was more sensitive to inaccuracies in both polar and azimuthal location than depth of the dipolar source. For polar locations, an ER > 1.0 was achieved when the beamformer was located within +/- 25 degrees of a radial dipole and +/- 35 degrees of a tangential dipole. Similarly, angular ranges of +/- 37.5 degrees and +/- 45 degrees, respectively, for inaccuracies in azimuthal locations. Preliminary results from real EEG records, comprising 12 definite or questionable epileptiform events, from four patients, demonstrated the beamformer's ability to enhance these events by a mean 100% (52%-215%) for referential data and a mean 104% (50%-145%) for bipolar data.

The proinflammatory and chondral activities of leukemia inhibitory factor in goat joints are partially a function of interleukin-1.

We wished to determine if the effects of injected recombinant human leukemia inhibitory factor (LIF) are a function of endogenous goat interleukin-1 (IL-1) production and, conversely, if the effects of injected recombinant human IL-1 are a function of endogenous LIF production in goat radiocarpal joints (RCJ). In preliminary experiments, murine LIF binding protein (MuLBP) and recombinant HuIL-1RA were found to independently attenuate the cartilage proteoglycan resorbing activity of goat synovial membrane-conditioned medium (GSMCM), implying activity against goat LIF and goat IL-1, respectively. The present study shows that the proinflammatory and chondral actions of rHuLIF in goat RCJ are partially attenuated by rHuIL-1RA. This implies that a small but important component of the in vivo activity of rHuLIF is a result of IL-1 production in the synovial joint. With the exception of proteoglycan synthesis, the absence of significant effects by MuLBP on the actions of rHuIL-1alpha in goat RCJ suggests that the proinflammatory and chondral effects of IL-1alpha in vivo are probably not mediated by LIF.

Oncostatin M induces leukocyte infiltration and cartilage proteoglycan degradation in vivo in goat joints.

OBJECTIVE: To evaluate the effect of intraarticular injections of recombinant human oncostatin M (rHuOSM) in the goat joint. METHODS: One milliliter of endotoxin-free normal saline (vehicle) containing either 40 ng, 200 ng, or 1,000 ng of rHuOSM was injected into the right radiocarpal joints (RCJs) of 12 male angora goats, while the left RCJs were injected with an equivalent volume of vehicle alone. In subsequent studies, the right and left RCJs of 8 male angora goats were injected with 200 ng of rHuOSM, and 1 hour later, the right RCJs were injected with either 5 microg of recombinant murine leukemia inhibitory factor binding protein (rMuLBP) or 1 mg of recombinant human interleukin-1 receptor antagonist (rHuIL-1Ra) in 1 ml of vehicle, while the left RCJs received 1 ml of vehicle alone. Goat joints were examined for clinical features of inflammation, and synovial fluid (SF) was aspirated on day 0 (before injection) and at days 2 and 6 postinjection. RESULTS: Injections of rHuOSM stimulated dose-dependent increases in the carpal:metacarpal ratio, SF volume, and SF leukocyte numbers, and stimulated dose-dependent decreases in the cartilage proteoglycan (PG) content ex vivo and PG synthesis. No significant changes were observed in the control joints that received saline alone, or between RCJs that were injected with 200 ng rHuOSM followed by 5 microg rMuLBP and RCJs that were injected with 200 ng of rHuOSM alone, except in respect to synovial fluid keratan sulfate concentrations, where a modest statistically significant reduction was observed in the joints injected with the combination of rHuOSM and rMuLPB. In contrast, RCJs injected with 200 ng rHuOSM followed by 1 mg of rHuIL-1Ra had significantly lower SF volumes (P<0.0001) and a significantly higher rate of ex vivo PG synthesis (P<0.0001). CONCLUSION: These results indicate that rHuOSM stimulates inflammation and modulates cartilage PG metabolism in vivo. Some of the effects of rHuOSM in vivo appear to be due, in part, to elaboration of IL-1. Even at very high doses, however, the rHuIL-1Ra did not attenuate OSM-mediated cartilage PG resorption. Thus, OSM has the potential to contribute to synovitis in vivo and can stimulate cartilage PG resorption in vivo, independent of IL-1.

Detection of epileptiform discharges in the EEG by a hybrid system comprising mimetic, self-organized artificial neural network, and fuzzy logic stages.

OBJECTIVE: A multi-stage system for automated detection of epileptiform activity in the EEG has been developed and tested on pre-recorded data from 43 patients. METHODS: The system is centred on the use of an artificial neural network, known as the self-organising feature map (SOFM), as a novel pattern classifier. The role of the SOFM is to assign a probability value to incoming candidate epileptiform discharges (on a single channel basis). The multi-stage detection system consists of three major stages: mimetic, SOFM, and fuzzy logic. Fuzzy logic is introduced in order to incorporate spatial contextual information in the detection process. Through fuzzy logic it has been possible to develop an approximate model of the spatial reasoning performed by the electroencephalographer. RESULTS: The system was trained on 35 epileptiform EEGs containing over 3000 epileptiform events and tested on a different set of eight EEGs containing 190 epileptiform events (including one normal EEG). Results show that the system has a sensitivity of 55.3% and a selectivity of 82% with a false detection rate of just over seven per hour. CONCLUSIONS: Based on these initial results the overall performance is favourable when compared with other leading systems in the literature. This encourages us to further test the system on a larger population base with the ultimate aim of introducing it into routine clinical use.

Modulation of cartilage proteoglycan metabolism by LIF binding protein.

Leukaemia inhibitory factor (LIF) and oncostatin M (OSM) exhibit pleiotropic biological activities, share many structural and genetic features and bind with high affinity to the same receptor (LIF/OSM receptor). A soluble form of the LIF-R alpha, called LIF binding protein (LBP) has been isolated from mouse serum. LIF and OSM stimulate proteoglycan (PG) release and inhibit PG synthesis in cultured pig articular cartilage explants. The aim of this study was to determine whether LBP can block PG resorption and or reverse the inhibition of PG synthesis induced by LIF and OSM. In cultured pig cartilage explants LBP was found to dose dependently inhibit LIF stimulated release of PGs and reverse the suppression of PG synthesis. LBP was found to substantially attenuate the effects of LIF. In contrast only partial inhibition of the stimulatory effect of OSM was observed at the highest concentration of LBP available. At maximal concentrations, LBP produced minimal reversal of OSM mediated inhibition of PG synthesis. When tested in combination LIF and OSM had no additive effects on PG metabolism, but the combination of LIF and IL-1 and also OSM and IL-1 did show additive effects in respect to stimulation of PG catabolism and inhibition of PG synthesis. These effects were significantly greater than those observed for LIF, OSM and IL-1 alone. The results suggest that pig articular chondrocytes possess the LIF/OSM receptor, but possibly not an independent OSM receptor. The actions of mLBP indicate that rhLBP could be a clinically useful antagonist for LIF and perhaps OSM.

Monoarthropathy. Could this be infection?

BACKGROUND: Monoarthritis in an adult presents a diagnostic challenge. Monoarticular symptoms usually imply local joint pathology, but may be a referred phenomenon, a feature of a periarticular syndrome such as a stress fracture or the dominant manifestation in polyarticular disease. OBJECTIVE: When confronted with an acute or subacute monoarthritis, exclusion of sepsis is essential and wherever feasible joint aspiration and diagnostic analysis of synovial fluid should be undertaken. DISCUSSION: A history of joint stiffness, restricted joint movements and the presence of an effusion are generally helpful indicators of true arthritis. Synovial fluid examination is the single most informative investigation that can be performed in this clinical setting. It should include a total and differential leucocyte count, scrutiny for crystals under polarized light and microscopy and culture for organisms. In the absence of organisms or crystals, the presence or absence of blood in the aspirate and the number and type of leucocytes will assist in the differentiation of other diagnostic possibilities.

Multireference adaptive noise canceling applied to the EEG.

The technique of multireference adaptive noise canceling (MRANC) is applied to enhance transient nonstationarities in the electroeancephalogram (EEG), with the adaptation implemented by means of a multilayer-perception artificial neural network (ANN). The method was applied to recorded EEG segments and the performance on documented nonstationarities recorded. The results show that the neural network (nonlinear) gives an improvement in performance (i.e., signal-to-noise ratio (SNR) of the nonstationarities) compared to a linear implementation of MRANC. In both cases an improvement in the SNR was obtained. The advantage of the spatial filtering aspect of MRANC is highlighted when the performance of MRANC is compared to that of the inverse auto-regressive filtering of the EEG, a purely temporal filter.

Leukemia inhibitory factor (LIF) binding protein attenuates the phlogistic and abolishes the chondral effects of LIF in goat joints.

OBJECTIVE: To investigate the ability of murine leukemia inhibitory factor (LIF) binding protein (mLBP) to attenuate the effects of recombinant human LIF (rhLIF) in goat radiocarpal joints in vivo. METHODS: Endotoxin-free saline (1 ml) containing either 0.5 or 1 microg of rhLIF was injected into the left and right radiocarpal joints of male angora goats. One hour later the right radiocarpal joints were injected with either 1 or 5 microg of naturally occurring mLBP in 1 ml saline, while the left radiocarpal joints (controls) received 1 ml saline vehicle alone. Goat joints were examined for clinical features of inflammation and synovial fluid (SF) was aspirated on Day 0 (before injection) and Days 2 and 6 postinjection. Leukocyte counts and concentrations of keratan sulfate were determined in the SF. Proteoglycan synthesis and proteoglycan content of cartilage was determined ex vivo in cartilage explants obtained at Day 6. RESULTS: Preliminary time course studies in vitro showed that mLBP had to be added to cartilage explant cultures within 1 h of rhLIF for effective antagonism to occur. In joints injected with either 0.5 or 1 microg rhLIF significant increases in swelling, effusion volume, leukocyte counts, and SF keratan sulfate concentrations were observed relative to controls. Statistically significant depressions of ex vivo proteoglycan synthesis and in proteoglycan content of articular cartilage were also observed relative to controls. In joints injected with 1 microg rhLIF followed by 1 microg mLBP, statistically significant improvement was only observed in the rate of ex vivo cartilage proteoglycan synthesis. The observed rate did not differ significantly from that obtained in joints treated with vehicle alone. In contrast, in joints injected with 0.5 microg rhLIF followed by 5 microg mLBP, statistically significant improvement was observed in all variables. Treatment with 5 microg mLBP effectively negated the effects of rhLIF on joint swelling, effusion volume, leukocyte infiltration, and cartilage proteoglycan catabolism. CONCLUSION: Murine LBP has the ability to attenuate the phlogistic effects of rhLIF in radiocarpal joints of goats and also abolishes the stimulatory effect of rhLIF on cartilage proteoglycan catabolism and depression of ex vivo proteoglycan synthesis. These antiinflammatory and chondral effects suggest that a humanized derivative of mLBP could be a clinically useful antagonist for LIF in inflammatory diseases.

Leukemia inhibitory factor induces leukocyte infiltration and cartilage proteoglycan degradation in goat joints.

Recent studies have implicated leukemia inhibitory factor (LIF) in human joint disease. LIF is produced by cultured synovial cells and articular chondrocytes, stimulates cartilage and bone resorption, and has been detected in inflammatory exudates from arthritic joints. The aim of this study was to evaluate the effect of intraarticular injections of human recombinant LIF in the goat. Endotoxin-free, sterile normal saline containing 1 micrograms recombinant human LIF (rhLIF) was injected into the right radiocarpal joints (RCJs) of eight angora goats. The left RCJs were injected with an equivalent volume of vehicle alone (n = 6) or vehicle containing 1 micrograms human albumin (n = 2). Goat joints were examined for clinical features of inflammation, and synovial fluid (SF) was aspirated on days 0, 2, and 6 postinjection. Leukocyte counts and concentrations of keratan sulfate, IL-1 beta, and TNF-alpha were determined in the SF. Proteoglycan synthesis was determined ex vivo in cartilage explants obtained on day 6 postinjection. A statistically significant increase in joint swelling and effusion volume was observed in LIF-injected joints but not in control joints. In the LIF-injected RCJs, the leukocyte count increased from 82 +/- 9 cells/microliters before injection to 10,300 +/- 3357 cells/microliters at day 2 postinjection (p < 0.005) and declined to 678 +/- 113 cells/microliters at day 6 postinjection. Polymorphonuclear leukocytes and monocyte/macrophages predominated in the infiltrate. No appreciable change in leukocyte counts was observed in control joints.(ABSTRACT TRUNCATED AT 250 WORDS)

Leukaemia inhibitory factor (LIF) suppresses proteoglycan synthesis in porcine and caprine cartilage explants.

Leukaemia Inhibitory Factor (LIF) has been implicated in connective tissue damage in arthritis. We have previously shown that LIF stimulates proteoglycan release in pig cartilage explants. The aim of this study was to determine whether LIF modulates proteoglycan synthesis in vitro. The methods used were as follows: slices of pig and goat articular cartilage were incubated overnight in Dulbecco's modification of Eagles medium (DMEM), supplemented with 5% foetal calf serum (FCS) and then cultured for 48 h without FCS and either no cytokines (negative control) or LIF. During the final 6 h the tissue was cultured in sulphate free DMEM containing 35SO4. The radioactivity in the medium and tissue was determined in cetylpyridinium chloride precipitates. Biosynthetic activity was expressed as DPM per mg wet weight of cartilage. Dose-dependent suppression of proteoglycan synthesis was observed with murine and human recombinant LIF in pig and goat cartilage. The degree of inhibition was similar to the maximal suppression observed with IL-1 alpha, but was not IL-1 dependent. In conclusion, LIF is a potent inhibitor of proteoglycan synthesis in cultured pig and goat articular cartilage.