bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurophysiologic evidence for a central sensitization in patients with fibromyalgia
Authors: Desmeules J. A. , Cedraschi C. , Rapiti E. , Baumgartner E. , Finckh A. , Cohen P. , Dayer P. , Vischer T. L.
Published: May 2003

Objective

To determine whether abnormalities of peripheral and central nociceptive sensory input processing exist outside areas of spontaneous pain in patients with fibromyalgia (FM) as compared with controls, by using quantitative sensory testing (QST) and a neurophysiologic paradigm independent from subjective reports.

Methods

A total of 164 outpatients with FM who were attending a self‐management program were invited to participate in the study. Data for 85 patients were available and were compared with those for 40 non‐FM controls matched for age and sex. QST was performed using thermal, mechanical, and electrical stimuli at locations of nonspontaneous pain. Pain assessment was 2‐fold and included use of subjective scales and the spinal nociceptive flexion reflex (NFR), a specific physiologic correlate for the objective evaluation of central nociceptive pathways. Questionnaires regarding quality of life and the impact of FM were available.

Results

Participants were mainly middle‐aged women, with a mean disease duration of 8 years. Between‐group differences were significant for neurophysiologic, clinical, and quality of life measures. In patients with FM, peripheral QST showed significantly altered cold and heat pain thresholds, and tolerance to cold pain was radically reduced. The median NFR threshold in patients with FM (22.7 mA [range 17.5–31.7]) was significantly decreased compared with that in controls (33 mA [range 28.1–41]). A cutoff value of <27.6 mA for NFR provided sensitivity of 73% and specificity of 80% for detecting central allodynia in the setting of FM.

Conclusion

Our results strongly, although indirectly, point to a state of central hyperexcitability of the nociceptive system in patients with FM. The NFR can be used to assess central allodynia in FM. It may also help discriminate patients who may benefit from use of centrally acting analgesics.
Cytokine gene polymorphisms: Association with psoriatic arthritis susceptibility and severity
Authors: Balding Joanna , Kane David , Livingstone Wendy , Mynett‐Johnson Lesley , Bresnihan Barry , Smith Owen , FitzGerald Oliver
Published: May 2003

Objective

To determine whether functional cytokine gene polymorphisms influence disease susceptibility and phenotype in patients with psoriatic arthritis (PsA).

Methods

DNA was obtained from 147 PsA patients and 389 controls. Seven functional proinflammatory (interleukin‐1β [IL‐1β] +3953, IL‐6 −174, tumor necrosis factor α [TNFα] −308, TNFβ +252) and antiinflammatory (IL‐10 −1082, IL‐10 −592, IL‐1 receptor antagonist [intron 2, 86 bp, variable‐number tandem repeat]) gene polymorphisms were detected by polymerase chain reaction and restriction fragment length polymorphism assays.

Results

No significant difference in genotype frequencies was observed between the control and the PsA patient populations, and no association with Steinbrocker functional class, disease classification (polyarticular or oligoarticular), presence of spinal involvement, or age at PsA onset was observed. The presence of joint erosions was significantly associated with the TNFα −308 and TNFβ +252 polymorphisms (P < 0.0001 and P = 0.0017, respectively). Frequencies of the TNFα −308 and TNFβ +252 genotypes were also significantly different (P = 0.0078 and P = 0.0486, respectively) in a group of progressors (patients with early PsA in whom the number of joint erosions in the hands and feet increased over a median interval of 24 months) compared with a group of nonprogressors. Age at psoriasis onset was significantly associated with the TNFβ +252 and TNFα −308 polymorphisms (P = 0.0003 and P = 0.0081, respectively). The TNFB2B2 and TNFα −308 AA genotypes were associated with the earliest mean ages at psoriasis onset.

Conclusion

The TNFα −308 and TNFβ +252 polymorphisms were significantly associated with age at psoriasis onset, presence of joint erosions in PsA, and progression of joint erosions in early PsA. TNF gene polymorphisms may be useful prognostic markers in PsA, and these results support the rationale for using anti‐TNF treatment in patients with severe, progressive PsA.
Selective elimination of synovial inflammatory macrophages in rheumatoid arthritis by an Fcγ receptor I–directed immunotoxin
Authors: Van Roon Joel A. G. , Van Vuuren Anneke J. , Wijngaarden Siska , Jacobs Kim M. G. , Bijlsma Johannes W. J. , Lafeber Floris P. J. G. , Thepen Theo , Van De Winkel Jan G. J.
Published: May 2003

Objective

To determine whether monocyte/macrophages from rheumatoid arthritis (RA) patients can be selectively eliminated by a toxin‐conjugated antibody CD64–ricin A (CD64‐RiA) directed toward the high‐affinity receptor for IgG (FcγRI), exploiting the capacity of FcγRI to efficiently endocytose antibody which it has bound.

Methods

Mononuclear cells from peripheral blood (PB) and synovial fluid (SF) obtained from RA patients were cultured in the presence of CD64‐RiA. Cell death of monocyte/macrophages was measured by phenotypic changes (light‐scatter patterns and CD14 and FcγRI expression) and apoptosis (nuclear DNA fragmentation). We then tested whether CD64‐RiA–induced cell death of macrophages affected their capacity to stimulate antigen‐induced lymphocyte proliferation and to secrete cytokines. Additionally, the capacity of CD64‐RiA to inhibit proinflammatory activity and cartilage degradation by RA synovial tissue explants was evaluated.

Results

Inflammatory macrophages from RA SF expressed elevated levels of FcγRI and were selectively eliminated by CD64‐RiA via apoptotic cell death. Monocyte/macrophages from RA PB, which had lower levels of FcγRI expression, were much less affected. Induction of SF macrophage apoptosis was associated with efficient inhibition of antigen‐induced lymphocyte proliferation and a reduction in tumor necrosis factor α (TNFα) release. Consistent with these effects on SF macrophages, CD64‐RiA also inhibited TNFα production, interleukin‐1β production, and cartilage‐degrading activity of RA synovial tissue explants.

Conclusion

Together, these data underscore the crucial role of synovial macrophages in RA joint inflammation and indicate that selective elimination of these cells through FcγRI‐directed immunotoxins could be a novel approach to the treatment of RA.
β1 integrin–mediated signaling induces intercellular adhesion molecule 1 and Fas on rheumatoid synovial cells and Fas‐mediated apoptosis
Authors: Nakayamada Shingo , Saito Kazuyoshi , Fujii Koichi , Yasuda Manabu , Tamura Masahito , Tanaka Yoshiya
Published: May 2003

Objective

Rheumatoid arthritis (RA) synovial cells interact with inflammatory cells, as well as extracellular matrices, through integrins. However, the relevance of β1 integrin to inflammatory processes in RA remains unclear. We examined the role of β1 integrin–mediated signaling in RA.

Methods

Expression of cell‐surface molecules was assessed by FACScan. Engagement of β1 integrins was performed by crosslinking using a specific monoclonal antibody (mAb) and ligand matrices such as fibronectin or collagen. To determine the involvement of tyrosine kinases in β1 integrin–mediated signaling, the cells were pretreated with various inhibitors of intracytoplasmic signaling or were transfected with a wild‐type focal adhesion kinase (FAK) or a dominant negative truncation of the FAK expression plasmid via cationic liposome‐mediated transfection. Apoptosis of synovial cells was detected by double staining with propidium iodide and annexin V.

Results

β1 integrin was highly expressed on RA synovial cells. Engagement of β1 integrins by crosslinking as well as by ligand matrices markedly up‐regulated expression of intercellular adhesion molecule 1 (ICAM‐1) and Fas. Up‐regulation of ICAM‐1 and Fas induced by β1 integrin was mediated by the tyrosine kinase signaling pathway, especially involving FAK. Fas‐mediated early apoptotic change in the cells was amplified by β1 crosslinking.

Conclusion

Our results suggest that interaction of β1 integrins with extracellular matrix augments expression of ICAM‐1 and Fas on RA synovial cells, as well as Fas‐mediated apoptosis of synovial cells. This might lead to the spontaneous growth arrest through the Fas/Fas ligand pathway observed in RA synovitis.
Responses to the proinflammatory cytokines interleukin‐1 and tumor necrosis factor α in cells derived from rheumatoid synovium and other joint tissues involve nuclear factor κB–mediated induction of the Ets transcription factor ESE‐1
Authors: Grall Franck , Gu Xuesong , Tan Lujian , Cho Je‐Yoel , Inan Mehmet Sait , Pettit Allison R. , Thamrongsak Usanee , Choy Bob K. , Manning Cathy , Akbarali Yasmin , Zerbini Luiz , Rudders Susan , Goldring Steven R. , Gravallese Ellen M. , Oettgen Peter , Goldring Mary B. , Libermann Towia A.
Published: May 2003

Objective

To investigate the expression of the novel Ets transcription factor ESE‐1 in rheumatoid synovium and in cells derived from joint tissues, and to analyze the role of nuclear factor κB (NF‐κB) as one of the central downstream targets in mediating the induction of ESE‐1 by proinflammatory cytokines.

Methods

ESE‐1 protein expression was analyzed by immunohistochemistry using antibodies in synovial tissues from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). ESE‐1 messenger RNA (mRNA) levels were analyzed by reverse transcriptase–polymerase chain reaction or Northern blotting in human chondrocytes, synovial fibroblasts, osteoblasts, and macrophages, before and after exposure to interleukin‐1β (IL‐1β), tumor necrosis factor α (TNFα), or lipopolysaccharide (LPS) with or without prior infection with an adenovirus encoding the inhibitor of nuclear factor κB (IκB). The wild‐type ESE‐1 promoter and the ESE‐1 promoter mutated in the NF‐κB site were cloned into a luciferase reporter vector and analyzed in transient transfections. Electrophoretic mobility shift assays (EMSAs) and supershift assays with antibodies against members of the NF‐κB family were conducted using the NF‐κB site from the ESE‐1 promoter as a probe.

Results

Immunohistochemical analysis showed specific expression of ESE‐1 in cells of the synovial lining layer and in some mononuclear and endothelial cells in RA and OA synovial tissues. ESE‐1 mRNA expression could be induced by IL‐1β and TNFα in cells such as synovial fibroblasts, chondrocytes, osteoblasts, and monocytes. Transient transfection experiments and EMSAs showed that induction of ESE‐1 gene expression by IL‐1β requires activation of NF‐κB and binding of p50 and p65 family members to the NF‐κB site in the ESE‐1 promoter. Overexpression of IκB using an adenoviral vector blocked IL‐1β–induced ESE‐1 mRNA expression. Chromatin immunoprecipitation further confirmed that NF‐κB binds to the ESE‐1 promoter in vivo.

Conclusion

ESE‐1 is expressed in synovial tissues in RA and, to a variable extent, in OA, and is specifically induced in synovial fibroblasts, chondrocytes, osteoblasts, and monocyte/macrophages by IL‐1β, TNFα, or LPS. This induction relies on the translocation of the NF‐κB family members p50 and p65 to the nucleus and transactivation of the ESE‐1 promoter via a high‐affinity NF‐κB binding site. ESE‐1 may play a role in mediating some effects of proinflammatory stimuli in cells at sites of inflammation.
Two distinctive HLA haplotypes harbor the B27 alleles negatively or positively associated with ankylosing spondylitis in Sardinia: Implications for disease pathogenesis
Authors: Fiorillo Maria Teresa , Cauli Alberto , Carcassi Carlo , Bitti Pier Paolo , Vacca Alessandra , Passiu Giuseppe , Bettosini Francesca , Mathieu Alessandro , Sorrentino Rosa
Published: May 2003

Objective

To compare haplotype distribution in HLA–B27–positive patients with ankylosing spondylitis (AS) and healthy control subjects possessing either AS‐associated HLA–B27 alleles or the non–AS‐associated HLA–B*2709 allele.

Methods

DNA samples from 47 HLA–B27–positive patients with AS and 76 HLA–B27–positive healthy controls (19 positive and 57 negative for B*2709) living in different areas of Sardinia were collected and typed for HLA class I and class II alleles. The third exon of the B27 gene was analyzed for the presence of Asp116 or His116, which differentiates B*2709 from the other two B27 subtypes (B*2705 and B*2702) that are mostly found in Sardinia. The parents of 6 subjects positive for B*2709 were also typed for HLA class I and class II alleles. Statistical analysis was performed by Fisher's exact test.

Results

In Sardinia, the B27 alleles conferring susceptibility to AS appear to be more frequently carried by a haplotype (A2;B27;Cw2;DR16) that reaches its highest frequency in patients with AS (A2 80.8%, B27 100%, Cw2 83%, and DR16 74.5%). Conversely, the non–AS‐associated B*2709 allele is more frequently found together with other HLA alleles whose frequencies are inversely correlated with the disease (A32 or A30, Cw1, and DR12). Familial analysis of 6 subjects positive for HLA–B*2709 confirmed the existence of a “Sardinian” haplotype that is not associated with AS (A32;B*2709;Cw1;DR12).

Conclusion

In Sardinia, 2 distinct haplotypes harbor the non–AS‐associated HLA–B*2709 allele or the AS‐associated B27 alleles. Our findings are compatible with the hypothesis that other genes within the HLA region besides HLA–B27 may play some role in conferring susceptibility to AS.
Correlation between circulating CD27high plasma cells and disease activity in patients with systemic lupus erythematosus
Authors: Jacobi Annett M. , Odendahl Marcus , Reiter Karin , Bruns Anne , Burmester Gerd R. , Radbruch Andreas , Valet Günter , Lipsky Peter E. , Dörner Thomas
Published: May 2003

Objective

Disease activity in systemic lupus erythematosus (SLE) is usually assessed with complex disease activity scores comprising a variety of different parameters. In order to determine whether SLE disease activity correlates with abnormal B lymphocyte activity, B cell subsets were analyzed, and their relationship to clinical and humoral measures of disease activity was assessed.

Methods

The distribution of B cell subsets was determined by fluorescence‐activated cell sorting analysis and assessed in relation to the autoantibody profile, disease activity measured by the SLE Disease Activity Index (SLEDAI) and the European Consensus Lupus Activity Measure scores, disease duration, and therapy.

Results

The number and frequency of CD27high plasma cells were significantly correlated with the SLE disease activity indices and with the titer of anti–double‐stranded DNA (anti‐dsDNA) autoantibodies. Circulating B cell subsets were not influenced by age or sex, but appeared to relate to the duration of disease and the therapeutic regimen, with the number and frequency of CD27high plasma cells increasing and those of CD27− naive B cells decreasing over time. Patients were divided into those with a SLEDAI score of 0–8 (low disease activity) and those with SLEDAI score >8 (high disease activity). Patients with high disease activity had an increased frequency of both CD19+ B cells and CD27high plasma cells. By using a nonparametric data sieving algorithm, we observed that these B cell abnormalities provided predictive values for nonactive and active disease of 78.0% and 78.9%, respectively. The predictive value of the B cell abnormalities (78.9%) was greater than that of the humoral/clinical data pattern (71.4%), including anti‐dsDNA antibody levels, circulating immune complexes, increased erythrocyte sedimentation rate, mucocutaneous involvement, and acute renal involvement.

Conclusion

Flow cytometric monitoring of B cell subsets in the peripheral blood provides new insights into abnormalities of B cell function in SLE and may also be a diagnostically valuable option for monitoring the activity of this autoimmune disease.
Plasticity of clonal populations of dedifferentiated adult human articular chondrocytes
Authors: Barbero Andrea , Ploegert Sabine , Heberer Michael , Martin Ivan
Published: May 2003

Objective

To investigate whether adult human articular chondrocytes (AHACs), dedifferentiated by monolayer expansion, can differentiate toward diverse mesenchymal lineages and, if so, whether this ability is regulated by growth factors during monolayer expansion.

Methods

AHACs were expanded as multiclonal or clonal populations in medium without (control) or with factors enhancing cell dedifferentiation (transforming growth factor β1, fibroblast growth factor 2, and platelet‐derived growth factor type BB [TFP]). Cells were then cultured under conditions promoting chondrogenic, osteogenic, or adipogenic differentiation, and the acquired phenotypes were assessed histologically, biochemically, and by real‐time reverse transcriptase–polymerase chain reaction.

Results

Multiclonal populations of both control‐ and TFP‐expanded AHACs differentiated toward the chondrogenic, osteogenic, and adipogenic lineages. Compared with control‐expanded AHACs, TFP‐expanded cells displayed enhanced chondrogenic differentiation capacity (2.4‐fold higher glycosaminoglycan/DNA content and 2,500‐fold higher up‐regulation of type II collagen) and osteogenic differentiation capacity (9.4‐fold higher increase in alkaline phosphatase activity and 12.4‐fold higher up‐regulation of bone sialoprotein), but reduced formation of adipocytes (5.2‐fold lower oil red O–positive cells/area). Clonal populations of AHACs could be efficiently expanded in TFP, but not in control medium. Most TFP‐expanded clones were able to redifferentiate only into chondrocytes (7 of 20) or were unable to differentiate (6 of 20). However, some clones (2 of 20) differentiated toward all of the lineages investigated, thus displaying characteristics of mesenchymal progenitor cells.

Conclusion

Dedifferentiated AHACs exhibit differentiation plasticity, which is modulated by growth factors used during monolayer expansion and is highly heterogeneous across different clones. Clonal culture of AHACs in the presence of regulatory molecules could lead to the identification of AHAC subpopulations with enhanced cartilage repair capacity.
Involvement of CD44 in induction of matrix metalloproteinases by a COOH‐terminal heparin‐binding fragment of fibronectin in human articular cartilage in culture
Authors: Yasuda Tadashi , Poole A. Robin , Shimizu Makoto , Nakagawa Takefumi , Julovi Sohel M. , Tamamura Hirokazu , Fujii Nobutaka , Nakamura Takashi
Published: May 2003

Objective

To investigate the mechanism of induction of matrix metalloproteinases (MMPs) by a 40‐kd COOH‐terminal heparin‐binding fibronectin fragment (HBFN‐f) containing III12–14 and IIICS domains in human articular cartilage in culture.

Methods

Human articular cartilage was removed from macroscopically normal femoral heads and cultured with HBFN‐f. MMP secretion into conditioned media was analyzed by immunoblotting (MMPs 1 and 13) and by gelatin zymography (MMPs 2 and 9). Type II collagen cleavage by collagenase was monitored in culture by immunoassay. Involvement of specific peptide‐binding domains in HBFN‐f and the involvement of CD44 were assessed with synthetic peptides and an anti‐CD44 antibody. Immunofluorescence histochemistry was performed using fluorescein isothiocyanate–conjugated anti‐CD44 antibody.

Results

HBFN‐f stimulated production of MMPs 1, 2, 9, and 13 in association with type II collagen cleavage by collagenase in human articular cartilage. Peptide V (WQPPRARI) of HBFN‐f, which can bind cell surface heparan sulfate proteoglycan (HSPG), blocked MMP induction by HBFN‐f, while the scrambled peptide V (RPQIPWAR) had no effect. Peptide CS‐1 of 25 amino acids in IIICS of HBFN‐f caused no significant effect. Treatment of cartilage with anti‐CD44 antibody or HSPG resulted in significant inhibition of HBFN‐f–stimulated MMP production. Preincubation with peptide V blocked binding of the anti‐CD44 antibody to chondrocytes in cartilage.

Conclusion

Interaction of the peptide V sequence in HBFN‐f with glycosaminoglycans, such as those in CD44, plays an important role in HBFN‐f–stimulated MMP production in articular cartilage. Because CD44 is up‐regulated in osteoarthritic and rheumatoid arthritic cartilage, the role of the interaction between CD44 and HBFN‐f in these pathologies should be of relevance and should be studied further.
Genetic basis of tissue specificity of vasculitis in MRL/lpr mice
Authors: Yamada Akihiro , Miyazaki Tatsuhiko , Lu Ling‐Min , Ono Masao , Ito Mitsuko R. , Terada Miho , Mori Shiro , Hata Kazuya , Nozaki Yoshimi , Nakatsuru Shuichi , Nakamura Yusuke , Onji Morikazu , Nose Masato
Published: May 2003

Objective

To clarify the mode of inheritance of the tissue distribution of vasculitis in MRL/Mp‐lpr/lpr (MRL/lpr) lupus‐prone mice and to identify the susceptibility loci.

Methods

Vasculitis in individual MRL/lpr, C3H/HeJ‐lpr/lpr (C3H/lpr), (MRL/lpr × C3H/lpr)F1, and (MRL/lpr × C3H/lpr)F2 intercross mice was analyzed by histopathologic grading of main branches of the aorta and of medium‐sized arteries in the lower limbs. Genomic DNA samples from F2 intercross mice were examined by simple sequence‐length polymorphism analysis, and the polymorphic microsatellite markers highly associated with vasculitis in each tissue were determined as vasculitis susceptibility loci.

Results

A susceptibility locus with significant linkage to vasculitis of main branches of the aorta was mapped on chromosome 4 at D4Mit213 (map position 13.3cM) selectively in males, while vasculitis of medium‐sized arteries in the lower limbs was mapped to different chromosomes: at D8Mit31 on chromosome 8 (map position 33.0) selectively in females and at D5Mit36 on chromosome 5 (map position 65.0). All of these were different from the previously defined loci governing susceptibility to vasculitis involving the kidneys.

Conclusion

Systemic vasculitis in MRL/lpr mice is genetically controlled with cumulative effects of multiple gene loci, each of which has tissue specificity.
Dynamic gadolinium‐enhanced magnetic resonance imaging of the wrist in patients with rheumatoid arthritis can discriminate active from inactive disease
Authors: Cimmino Marco A. , Innocenti Stefania , Livrone Fabrizio , Magnaguagno Francesca , Silvestri Enzo , Garlaschi Giacomo
Published: May 2003

Objective

To determine the efficacy of dynamic gadolinium‐enhanced magnetic resonance imaging (MRI) of the wrist in the evaluation of disease activity in patients with rheumatoid arthritis (RA).

Methods

Thirty‐six patients with RA (with different degrees of disease activity) and 5 healthy controls were studied. MRI was performed with a low‐field (0.2T), extremity‐dedicated machine. After an intravenous bolus injection of gadolinium–diethylenetriamine pentaacetic acid, 20 consecutive fast spin‐echo images of 3 slices of the wrist were obtained every 18 seconds.

Results

The curves of synovial membrane enhancement identified the following 2 groups: controls and RA patients in remission, and RA patients with active or intermediately active disease. Both the rate of early enhancement (REE) and relative enhancement (RE) were significantly higher in patients with active RA than in those with inactive RA and controls. The REE and RE were significantly correlated with the number of swollen joints (P < 0.00001 and P = 0.003, respectively), the number of tender joints (P < 0.00001 and P = 0.004, respectively), the Ritchie index (P = 0.0002 for both REE and RE), the Disease Activity Score (P = 0.0004 and P = 0.0008, respectively), the Health Assessment Questionnaire (HAQ) (P = 0.0002 and P = 0.0007, respectively), early morning stiffness (P = 0.001 and P = 0.009, respectively), the C‐reactive protein level (P = 0.015 and P = 0.03, respectively), the erythrocyte sedimentation rate (P = 0.03, RE only), and α2 globulins (P = 0.036 and P = 0.028, respectively).

Conclusion

Our data support use of dynamic MRI for discriminating active from inactive RA. Enhancement curves are associated not only with laboratory and clinical indicators of inflammation, but also with the HAQ, a relevant predictor of RA functional outcome. This technique can be repeated frequently and is an excellent candidate for the ideal method for the followup of patients with RA.
Role of metacarpophalangeal joint anatomic factors in the distribution of synovitis and bone erosion in early rheumatoid arthritis
Authors: Tan Ai Lyn , Tanner Steven F. , Conaghan Philip G. , Radjenovic Aleksandra , O'Connor Philip , Brown Andrew K. , Emery Paul , McGonagle Dennis
Published: May 2003

Objective

To investigate the role of metacarpophalangeal (MCP) joint anatomic and biomechanical factors in the distribution of synovitis and bone erosion in early rheumatoid arthritis (RA).

Methods

Thirty‐three patients with early RA with clinically diagnosed MCP joint disease and 28 healthy controls were examined by magnetic resonance imaging of the second to fifth MCP joints of the dominant hand. T1 and T2 fat‐suppressed coronal sequences were obtained to assess erosion, and dynamic contrast‐enhanced images were acquired to assess synovitis in all of the RA patients and in 8 of the controls. Erosions were defined as bone defects with sharp margins observed using T1‐weighted imaging in 2 planes, with a cortical break seen in at least 1 plane. The location of erosions was recorded. The volume of synovitis surrounding each MCP joint (divided into 8 regions) was calculated by summation of voxels derived from the maximal enhancement parameters. The synovial volumes adjacent to MCP joint collateral ligaments were determined by correcting synovial volumes for the positions of asymmetrically placed flexor tendons.

Results

In patients with early RA in whom bone erosions were present, there was a propensity for involvement of the radial side of the second (P < 0.0001), third (P = 0.002), and fourth (P = 0.056) MCP joints, but not the fifth. Fifty‐two of the 110 erosions (47.3%) occurred adjacent to the radial collateral ligaments of the second, third, and fourth MCP joints. The volume of synovitis was also greater on the radial side of the second (P < 0.0001) and third (P < 0.001) MCP joints. A predilection for synovitis in all of the MCP joints adjacent to the radial collateral ligaments was evident when the positional effects of the flexor tendon were considered. The position of radial collateral ligaments had an effect on erosion formation that was independent of synovitis. A predilection for radial bone damage was also evident in the controls, although lesions were 5‐fold less frequent, were generally smaller, and had well‐defined margins.

Conclusion

This study shows that there is a predilection for both synovitis and bone erosion formation on the radial side of the MCP joints in early RA, and that joint inflammation appears to drive the inherent tendency for bone damage on the radial side of joints. These findings have implications regarding the pathogenesis of joint damage in RA.
Amyloid‐enhancing factor mediates amyloid formation on fibroblasts via a nidus/template mechanism
Authors: Magy Nadine , Liepnieks Juris J. , Benson Merrill D. , Kluve‐Beckerman Barbara
Published: May 2003

Objective

To determine the mechanism by which amyloid‐enhancing factor (AEF) promotes amyloid deposition, and to test whether AEF seeds deposition of serum amyloid A (SAA) and facilitates conversion to beta‐sheet structure.

Methods

Fibroblasts were cultured with mouse recombinant SAA1.1 and AEF, SAA1.1, or AEF. AEF was prepared as a glycerol extract of spleen from amyloidotic mice. Amyloid was identified by staining with Congo red and examining for green birefringence under polarized light. SAA was localized immunohistochemically. Texas Red–labeled SAA was visualized in living cultures by fluorescence confocal microscopy. AEF was characterized by Western blot analysis using anti‐SAA antiserum and N‐terminal sequence analysis. Subunits comprising amyloid in fibroblast cultures were characterized by sodium dodecyl sulfate–polyacrylamide gel electrophoresis.

Results

Amyloid was produced in fibroblast cultures by an AEF‐dependent mechanism. AEF, added to culture medium as insoluble protein precipitates, adhered to fibroblast monolayers. SAA bound preferentially to the adherent precipitates. Coincident with SAA binding, precipitates developed an affinity for Congo red. Over time, as more SAA was added, networks of Congo red–positive material producing bright green birefringence also developed outward from AEF precipitates. Amyloid built upon AEF in this manner was composed of full‐length SAA. No amyloid was produced in cultures treated with either SAA or AEF alone. SAA and SAA peptides processed in the C‐terminal region were the most prominent proteins in the glycerol‐extracted AEF preparation.

Conclusion

AEF binds to fibroblast monolayers and acts as a sink for SAA. SAA that collects on AEF assembles into an amyloid structure. Thus, it is concluded that AEF serves as both a nidus and a template for amyloid formation.
Nonsteroidal antiinflammatory drugs and a selective cyclooxygenase 2 inhibitor uncouple mitochondria in intact cells
Authors: Krause Manja M. , Brand Martin D. , Krauss Stefan , Meisel Christian , Vergin Hartmut , Burmester Gerd‐Rüdiger , Buttgereit Frank
Published: May 2003

Objective

Uncoupling of isolated mitochondria by nonsteroidal antiinflammatory drugs (NSAIDs) has been considered relevant to the development of gastrointestinal (GI) side effects. We investigated the occurrence of NSAID‐induced uncoupling of mitochondria in intact cells (rat thymocytes) compared with the effects of a selective cyclooxygenase 2 (COX‐2) inhibitor.

Methods

Oxygen consumption and mitochondrial membrane potential were simultaneously measured amperometrically and by distribution of radioactive tracer molecules, respectively, in the presence and absence of pharmacologically relevant concentrations of the NSAIDs indomethacin and diclofenac and the selective COX‐2 inhibitor SC‐236. Analysis of data by a technique related to top‐down elasticity analysis permitted assessment of the influence of these compounds on individual components of cellular energy metabolism.

Results

Indomethacin, diclofenac, and SC‐236 increased proton leak in isolated mitochondria. Both diclofenac and SC‐236 significantly stimulated proton leak in intact cells and simultaneously inhibited substrate oxidation and ATP turnover. Oxygen consumption rates of isolated cells remained unchanged over a wide concentration range of the drugs, despite significant effects on subsystems of cellular energy metabolism.

Conclusion

NSAIDs and selective COX‐2 inhibitors have significant and equally directed effects on cellular energy metabolism. They both uncouple mitochondrial respiration and inhibit substrate oxidation and ATP turnover. However, the topical effect and selective COX‐2 inhibition may not be sufficient to cause NSAID‐like damage to the GI tract.
Deposition of nucleosomal antigens (histones and DNA) in the epidermal basement membrane in human lupus nephritis
Authors: Grootscholten Cecile , van Bruggen Mieke C. J. , van der Pijl Johan W. , de Jong Elke M. G. J. , Ligtenberg Gerry , Derksen Ronald H. W. M. , Berden Jo H. M. ,   for the Dutch Working Party on Systemic Lupus Erythematosus
Published: May 2003

Objective

Antinuclear autoantibodies complexed to nucleosomes can bind to heparan sulfate (HS) in the glomerular basement membrane. This binding is due to the binding of the positively charged histones to the strongly anionic HS. Nucleosomes and histones have been identified in glomerular deposits in human lupus nephritis. We investigated whether nucleosomes are present in the basement membrane of nonlesional skin of lupus patients.

Methods

Skin biopsy samples from patients with systemic lupus erythematosus (SLE) (30 with active lupus nephritis and 15 with inactive disease) and controls (with parapemphigus or diabetes) were stained for IgG, histones, DNA, and nucleosomes.

Results

IgG deposits were found in 87% of the patients with lupus nephritis, in 33% of the patients with inactive disease, and in 71% of the parapemphigus patients. Using polyclonal antihistone antibodies, histones were detected in 87% of lupus nephritis patients, but in none of the other SLE patients or the diabetes controls (P < 0.0001). Among the parapemphigus controls, 14% of samples stained positive in one of the polyclonal antihistone stainings (P < 0.0001). Using monoclonal antibodies, histones and DNA were identified in 21% of the lupus nephritis patients. Although none of the other groups showed positive staining for nucleosomes, 7% of the lupus nephritis biopsy samples were positive using antinucleosome monoclonal antibodies. Colocalization of nucleosomal antigens and IgG was confirmed using confocal laser microscopy.

Conclusion

These findings suggest that nucleosome‐mediated binding of autoantibodies to basement membranes may also occur at sites in the body other than in the glomerulus.
Correlation of serum anti‐DNA topoisomerase I antibody levels with disease severity and activity in systemic sclerosis
Authors: Hu Paul Q. , Fertig Noreen , Medsger Thomas A. , Wright Timothy M.
Published: May 2003

Objective

To investigate correlations between serum levels of topoisomerase I–specific antibody (anti–topo I) and clinical features of systemic sclerosis (SSc), including disease severity (the total skin score [TSS]) and disease activity.

Methods

Using highly sensitive enzyme‐linked immunosorbent assays, we measured the levels of anti–topo I antibody, including total IgG, individual IgG subclasses, and IgA, and analyzed their correlations with the TSS in 59 patients with SSc, all of whom had diffuse cutaneous involvement. Serial serum samples were obtained from 11 of these patients.

Results

The titers of anti–topo I antibody, including IgG and IgA, were positively correlated with the TSS, a measure of SSc disease severity. In 8 of the 11 patients from whom serial serum samples were obtained, changes in the levels of both IgG and IgA, when detectable, paralleled changes in the TSS. In 3 patients, an increasing anti–topo I IgG level preceded an increase in the TSS. The level of each IgG subclass also correlated with and tended to parallel the TSS. The patients with very active disease had higher mean IgG (P < 0.001) and IgA (P < 0.05) titers than did those with inactive disease.

Conclusion

Serum levels of anti–topo I antibody correlate positively with disease severity and disease activity in SSc.
Increased ubiquitination and reduced expression of LCK in T lymphocytes from patients with systemic lupus erythematosus
Authors: Jury Elizabeth C. , Kabouridis Panagiotis S. , Abba Amina , Mageed Rizgar A. , Isenberg David A.
Published: May 2003

Objective

To explore regulation of proximal signaling and composition of lipid rafts in T lymphocytes from patients with systemic lupus erythematosus (SLE).

Methods

The expression, phosphorylation, and degradation of lipid raft–associated signaling molecules in T lymphocytes from 50 patients with SLE compared with 28 healthy controls and 22 rheumatoid arthritis patients were investigated. Lipid raft and nonraft fractions from T cells were isolated by ultracentrifugation. Proteins in the lipid raft and nonraft fractions were analyzed by Western blotting and probed for phosphotyrosine activity and for LCK, LAT, and CD3ε. Immunoprecipitation experiments were performed to assess protein ubiquitination in T cell lysates. T cell phenotype and levels of intracellular LCK were determined by flow cytometry.

Results

LCK, an essential signaling molecule for T cell activation, was significantly reduced in both lipid raft and nonraft fractions of T lymphocytes from patients with active SLE compared with controls, and the reduction was independent of treatment. To identify the likely causes of reduced LCK, we explored the possibility that chronic activation of T lymphocytes underlies LCK degradation. The results revealed an increase in protein ubiquitination, and specifically LCK ubiquitination, in T cells from SLE patients. However, our findings suggest that the increase in ubiquitination is independent of T cell activation.

Conclusion

LCK is reduced in T cell lipid rafts from patients with SLE. This reduction appears to be independent of activation and may be associated with abnormal ubiquitin‐mediated regulation mechanisms.
Intravertebral clefts in osteoporotic vertebral compression fractures
Authors: McKiernan Fergus , Faciszewski Tom
Published: May 2003

Objective

To describe the characteristics, radiographic appearance, and significance of intravertebral clefts in vertebral compression fractures (VCFs) of patients with osteoporosis presenting for vertebroplasty.

Methods

This was a prospective radiographic study of 50 consecutive patients with 82 VCFs who underwent vertebroplasty at a tertiary referral center. Patients underwent imaging preoperatively with standing lateral and supine cross‐table lateral radiographs and magnetic resonance imaging (MRI). Standing lateral radiographs were also obtained postoperatively. Clefts were defined at the time of vertebroplasty as confluent reservoirs for polymethylmethacrylate (PMMA). Postoperatively, all images were reexamined for the presence and characterization of intravertebral clefts.

Results

Twenty‐four of 50 patients (48%) had clefted VCFs, and 30 of 82 VCFs (37%) contained clefts. Clefted VCFs were severe, dynamically mobile, and occurred primarily in the thoracolumbar junction. Clefts were detectable by standing lateral radiography in 14%, by supine cross‐table radiography in 64%, and by MRI in 96% of fractured vertebrae. Clefts occurred primarily in the anterosuperior portion of the vertebral body, and cleft margins appeared increasingly sclerotic in persistently mobile VCFs. PMMA fill patterns of clefted and unclefted VCFs were distinct.

Conclusion

Intravertebral clefts occur frequently in osteoporotic VCFs of patients who present for vertebroplasty. The radiographic characteristics of clefts evolve over time and can be indistinguishable from Kümmell's disease in severe, persistently mobile, clefted osteoporotic VCFs.
Insulin‐like growth factor 1–induced interleukin‐1 receptor II overrides the activity of interleukin‐1 and controls the homeostasis of the extracellular matrix of cartilage
Authors: Wang Jun , Elewaut Dirk , Veys Eric M. , Verbruggen Gust
Published: May 2003

Objective

We examined the effect of the insulin‐like growth factor 1 (IGF‐1)/IGF receptor I (IGFRI) autocrine/paracrine anabolic pathway on the extracellular matrix (ECM) of human chondrocytes and the mechanism by which IGF‐1 reverses the catabolic effects of interleukin‐1 (IL‐1).

Methods

Phenotypically stable human articular cartilage cells were obtained from normal cartilage and maintained in culture in alginate beads for 1 week to reach equilibrium of accumulated cell‐associated matrix (CAM) compounds. Levels of CAM components aggrecan and type II collagen (CII) and levels of intracellular IGF‐1, IL‐1α, and IL‐1β and their respective plasma membrane–bound receptors IGFRI, IL‐1 receptor I (IL‐1RI), and the decoy receptor IL‐1RII were assayed using flow cytometry to investigate the relationship between the autocrine/paracrine pathways and the homeostasis of ECM molecules in the CAM. The effects of IGF‐1 on the expression of IGF‐1, IL‐1α, and IL‐1β and their respective receptor systems, the aggrecan core protein, and CII were determined by flow cytometry.

Results

Cause–effect relationship experiments showed that IGF‐1 up‐regulates the levels of IGF‐1, IGFRI, aggrecan, and CII in the CAM. No effects on the expression of IL‐1α and IL‐1β and their signaling receptor IL‐1RI were observed. However, IGF‐1 was able to reverse IL‐1β–mediated degradation of aggrecan and the repression of the aggrecan synthesis rate. Interestingly, levels of aggrecan and CII in the CAM strongly correlated not only with IGF‐1, but also with IL‐1RII, which acts as a decoy receptor for IL‐1α and IL‐1β. This suggests that IGF‐1 and IL‐1RII may cooperate in regulating ECM homeostasis. Additional experiments demonstrated that IGF‐1 up‐regulated IL‐1RII, thereby overriding the catabolic effects of IL‐1.

Conclusion

These findings reveal a new paradigm by which IGF‐1 influences chondrocyte metabolism, by reversing the IL‐1–mediated catabolic pathway through up‐regulation of its decoy receptor.
Inflammatory cytokine gene expression in the urinary sediment of patients with lupus nephritis
Authors: Chan Rebecca Wing‐Yan , Tam Lai‐Shan , Li Edmund Kwok‐Ming , Lai Fernand Mac‐Moune , Chow Kai‐Ming , Lai Ka‐Bik , Li Philip Kam‐Tao , Szeto Cheuk‐Chun
Published: May 2003

Objective

Lupus nephritis is characterized by intrarenal inflammation and lymphocyte activation. In the present study, the expression of cytokine genes in the urinary sediment of patients with systemic lupus erythematosus (SLE) was examined.

Methods

We studied 3 SLE patient groups (25 with active lupus nephritis [active group], 25 with inactive SLE and previous renal involvement [remission group], 20 with inactive SLE and no history of renal involvement [nonrenal SLE group]) and 2 control groups (10 patients with noninflammatory renal diseases [non‐SLE group] and 10 healthy volunteers [healthy group]). Cytokine gene expression in the urinary sediment was studied by real‐time quantitative polymerase chain reaction.

Results

Expression of interferon‐γ (IFNγ) in urinary sediment was significantly higher in the active group than in all other groups (P < 0.001 by Kruskal‐Wallis test). Among the SLE patient groups, there was a close correlation between IFNγ expression and the overall SLE Disease Activity Index (SLEDAI) score (Spearman's r = 0.590, P < 0.001) and the SLEDAI renal score (r = 0.642, P < 0.001). Urinary expression of interleukin‐2 (IL‐2) in the active group was significantly higher than that in the healthy group (P = 0.046) but not in the remission or nonrenal SLE groups. There was no difference in the levels of IL‐4 expression among the SLE groups.

Conclusion

We found a predominance of Th1 cytokine in the urinary sediment of patients with active lupus nephritis. Measurement of cytokine gene expression in urinary sediment may be a useful noninvasive tool for assessing the severity of renal involvement in SLE.
CD25+ cell depletion hastens the onset of severe disease in collagen‐induced arthritis
Authors: Morgan Mary E. , Sutmuller Roger P. M. , Witteveen Hendrik J. , van Duivenvoorde Leonie M. , Zanelli Eric , Melief Cornelis J. M. , Snijders Alies , Offringa Rienk , de Vries René R. P. , Toes René E. M.
Published: May 2003

Objective

CD4+,CD25+ T regulatory cells may offer opportunities to intervene in the course of autoimmune disease. We wished to evaluate their potential for influencing systemic and chronic joint inflammation by investigating their involvement in collagen‐induced arthritis (CIA).

Methods

We depleted DBA/1 mice of CD25+ regulatory cells by injection of a depleting monoclonal antibody specific for CD25 14 days before a single immunization with type II collagen (CII) in Freund's complete adjuvant. CD4+,CD25+ T cells were adoptively transferred to some groups of mice during immunization. Mice were then scored for signs of arthritis, and blood was taken periodically to measure the amounts of CII‐specific antibodies. Splenocytes of treated mice were examined in vitro to determine the effects of depletion on proliferation to CII and control antigens.

Results

CD25+ cell–depleted DBA/1 mice had significantly more severe disease than control mice following collagen immunization. The magnified severity was also accompanied by higher antibody titers against collagen, and in vitro tests showed increased proliferation of collagen‐specific T cells. Adoptively transferring CD4+,CD25+ T cells into depleted mice was shown to reverse the heightened severity. Control mice, which were depleted and immunized with the neoantigen keyhole limpet hemocyanin (KLH), had neither an increased antibody response toward KLH nor an augmented proliferative response, indicating that CD25+ cell depletion preferentially affects immunity against self antigen.

Conclusion

These results establish a link between CD4+,CD25+ regulatory cells and CIA and provide a rationale for investigating CD4+,CD25+ T regulatory cells in the treatment and prevention of arthritis.
Quantitative morphologic classification of layer 5 neurons from mouse primary visual cortex
Authors: Tsiola Areti , Hamzei‐Sichani Farid , Peterlin Zita , Yuste Rafael
Published: May 2003

The understanding of any neural circuit requires the identification and characterization of all its components. Morphologic classifications of neurons are, therefore, of central importance to neuroscience. We use a quantitative method to classify neurons from layer 5 of mouse primary visual cortex, based on multidimensional clustering. To reconstruct neurons, we used Golgi impregnations and biocytin injections, as well as DiOlistics, a novel technique of labeling neurons with lipophilic dyes. We performed computerized 3‐D reconstructions of 158 layer 5 cells to measure a series of morphologic variables. Principal component analysis and cluster analysis were used for the classification of cell types. Five major classes of cells were found: group 1 includes large pyramidal neurons with apical dendrites that reach layer 1 with an apical tuft; group 2 consists of short pyramidal neurons and large multipolar cells with “polarized” dendritic trees; group 3 is composed of less extensive pyramidal neurons; group 4 includes small cells; and group 5 includes another set of short pyramidal neurons in addition to “atypically oriented” cells. Our sample included a relatively homogeneous group of 27 neurons that project to the superior colliculus, which clustered mainly in group 1, thus supporting the validity of the classification. Cluster analysis of neuronal morphologies provides an objective method to quantitatively define different neuronal phenotypes and may serve as a basis for describing neocortical circuits. J. Comp. Neurol. 461:415–428, 2003. © 2003 Wiley‐Liss, Inc.
GFAP knockout mice have increased levels of GDNF that protect striatal neurons from metabolic and excitotoxic insults
Authors: Hanbury Rose , Ling Zao Dung , Wuu Joanne , Kordower Jeffrey H.
Published: May 2003

In response to injury and degeneration, astrocytes hypertrophy, extend processes, and increase production of glial fibrillary acidic protein (GFAP), an intermediate filament protein located within their cytoplasm. The present study tested the hypothesis that GFAP expression alters the vulnerability of neurons to excitotoxic and metabolic insult induced by 3‐nitroproprionic acid (3‐NP), an irreversible inhibitor of mitochondrial complex II activity or the excitotoxin quinolinic acid (QA). In this respect, adult GFAP knockout mice (KO) and wild‐type control mice (WT) received unilateral intrastriatal injections of 3‐NP (200 nmol/μl) or QA (100 nmol/μl) and were killed 1, 2, or 4 weeks later. Lesion volume and neuronal counts were quantified using unbiased stereologic principles. For both QA and 3‐NP lesions, a significant decrease in lesion volume and an increase in striatal projection neurons were seen in GFAP KO mice compared with WT mice. Enzyme‐linked immunoassay analysis revealed increased basal levels of glial cell derived neurotrophic factor (GDNF) relative to WT mice. In contrast, no differences were observed in the expression of ciliary neurotrophic factor or nerve growth factor. These data strongly suggest that the expression of GFAP is implicated with the production of GDNF to a degree that confers neuroprotection after an excitotoxic or metabolic insult. J. Comp. Neurol. 461:307–316, 2003. © 2003 Wiley‐Liss, Inc.