Gerd Weseloh

Independent expression of fibril-forming collagens I, II, and III in chondrocytes of human osteoarthritic cartilage.

Normal and osteoarthritic human articular cartilage was investigated by in situ hybridization for expression patterns of the fibrillar collagens type I, II, and III to evaluate phenotypic changes of articular chondrocytes related to the disease. In 11 out of 20 samples, a defined subset of chondrocytes in the superficial and upper middle zone of osteoarthritic cartilage showed significant levels of cytoplasmic alpha 1 (III) mRNA, whereas strong signals of alpha 1 (II) mRNA were found in the upper and lower middle zone, partially overlapping with the zone of alpha 1 (III) mRNA-expressing cells. The extent of type II and III collagen expression depended on the integrity of the extracellular matrix surrounding the chondrocytes, and the location within the articular cartilage. No alpha 1 (I) mRNA was detectable in osteoarthritic original articular cartilage. The alpha 1 (I) probe did, however, reveal signals in pannus-like tissue, osteophytes, and bone cells. In normal articular cartilage, no detectable levels of cytoplasmic mRNA for alpha 1(I), alpha 2 (I), or alpha 1 (III) were seen. Using specific mono- and polyclonal antibodies, we found deposition of type III collagen but hardly any of type I collagen in the superficial zone of osteoarthritic cartilage that is consistent with the in situ hybridization results. These results indicate a phenotypic alteration in a defined subset of chondrocytes in conditions of diseased cartilage, expressing and synthesizing collagen type III independently from type I collagen, but in part simultaneously with type II collagen.

Activation of collagen type II expression in osteoarthritic and rheumatoid cartilage

SummaryIn situ hybridization and immunohistochemical techniques were applied to investigate gene expression and extracellular deposition of collagen type II in normal, osteoarthritic and rheumatoid human articular cartilage. Normal cartilage showed an essentially even extracellular distribution of type II collagen with polyand monoclonal antibodies, while only a few cells were positive for al(II) collagen mRNA. In situ hybridization of osteoarthritic and rheumatoid cartilage, however, showed strong enhancement of type II collagen gene expression; transcripts were observed predominantly in the upper middle zone of the articular cartilage while the upper layer was mostly negative and correlated with a zone of reduced proteoglycan staining. The elvated mRNA levels frequently coincided with pericellular immunostaining ] for type II collagen, indicative for enhanced synthesis of the protein. In two samples, however, pericellular loss of collagen type II staining was found despite positive cytoplasmic signals with the α 1(11) RNA probe, suggesting enhanced collagen destruction. Control hybridization with a probe for 18S rRNA revealed very few negative cells throughout both normal and arthritic cartilage samples, ruling out major cell necrosis in the specimens investigated. Thus, our observations identify sites of activated type II collagen synthesis in osteoarthritic cartilage that were predicted by previous biochemical studies and support the notion that damaged cartilage attempts to restore matrix by enhanced synthesis of its components.

Vascular endothelial growth factor in articular cartilage of healthy and osteoarthritic human knee joints

OBJECTIVE To determine the levels of vascular endothelial growth factor (VEGF) mRNA and protein expression in normal and osteoarthritic (OA) human articular cartilage, and whether VEGF expression alters during the progression of OA. METHODS Sections from normal and OA human knee cartilage were immunotained with a polyclonal antibody recognising VEGF. In addition, total RNA was isolated from normal and osteoarthritic human knee cartilage and analysed by reverse transcriptase-polymerase chain reaction (RT-PCR) for VEGF mRNA expression. RESULTS VEGF was found to be present in normal and OA human knee cartilage in all cartilage layers. A significant increase of VEGF immunopositive chondrocytes to up to ∼82% was detected in severe OA cartilage compared with normal articular cartilage (∼56% of immunopositive chondrocytes). RT-PCR analysis showed the expression of VEGF also on the mRNA level. CONCLUSIONS VEGF is expressed by articular chondrocytes in normal and OA human knee cartilage. The percentage of VEGF immunopositive chondrocytes significantly increases in late stages of the disease. The VEGF transcript levels encoding all four isoforms shows a big variability in samples from different donors, suggesting a distinct regulation of the expression of the four VEGF isoforms in normal and OA cartilage.

Osteopontin is expressed by adult human osteoarthritic chondrocytes: protein and mRNA analysis of normal and osteoarthritic cartilage

Osteopontin, a sulfated phosphoprotein with cell binding and matrix binding properties, is expressed in a variety of tissues. In the embryonic growth plate, osteopontin expression was found in bone-forming cells and in hypertrophic chondrocytes. In this study, the expression of osteopontin was analyzed in normal and osteoarthritic human knee cartilage. Immunohistochemistry, using a monoclonal anti-osteopontin antibody was negative on normal cartilage. These results were confirmed in Western blot experiments, using partially purified extracts of normal knee cartilage. No osteopontin gene expression was observed in chondrocytes of adult healthy cartilage, however, in the subchondral bone plate, expression of osteopontin mRNA was detected in the osteoblasts. In cartilage from patients with osteoarthritis, osteopontin could be detected by immunohistochemistry, Western blot analysis, in situ hybridization, and Northern blot analysis. A qualitative analysis indicated that osteopontin protein deposition and mRNA expression increase with the severity of the osteoarthritic lesions and the disintegration of the cartilaginous matrix. Osteopontin expression in the cartilage was limited to the chondrocytes of the upper deep zone, showing cellular and territorial deposition. The strongest osteopontin detection was found in deep zone chondrocytes and in clusters of proliferating chondrocytes from samples with severe osteoarthritic lesions. These data show the expression of osteopontin in adult human osteoarthritic chondrocytes, suggesting that chondrocyte differentiation and the expression of differentiation markers in osteoarthritic cartilage resembles that of epiphyseal growth plate chondrocytes.

Expression of thrombospondin-1 and its receptor CD36 in human osteoarthritic cartilage.

OBJECTIVE Thrombospondin-1 (TSP-1), a trimeric glycoprotein, is involved in cell-matrix interactions of various tissues, particularly in cartilage. Biochemical analyses show expression of TSP-1 in human cartilage, but its cellular source as well as the presence of its main surface receptors CD36 and CD51 in normal and osteoarthritic cartilage remain unknown. Therefore, to localise TSP-1 and its receptors immunohistochemistry and in situ hybridisation were used. METHODS Radioactive in situ hybridisations with an RNA probe that encodes TSP-1 combined with immunostaining were carried out to investigate the expression patterns of TSP-1, CD36, and CD51 in seven normal and 23 osteoarthritic human cartilage samples. RESULTS In normal cartilage TSP-1 was present mainly in the middle and upper deep zone. RNA expression was predominantly seen over chondrocytes of the middle zone. CD36 was found in chondrocytes of the superficial and upper middle zone. In mild and moderate osteoarthritic cartilage an increased number of TSP-1 expressing chondrocytes were seen and an increased pericellular staining close to the surface. In severe osteoarthritic cartilage a decrease in the number of TSP-1 synthesising chondrocytes and a strong reduction in matrix staining were observed. Most of these severe osteoarthritic samples showed a strongly enhanced number of CD36 positive chondrocytes. CONCLUSION The cellular source of TSP-1 in normal cartilage is mainly mid-zone chondrocytes, which also express CD36. In early osteoarthritic cartilage lesions an increase of TSP-1 was seen, whereas reduced TSP-1 synthesis is paralleled by a strong decrease in TSP-1 protein staining in severe osteoarthritis. Furthermore, in severe osteoarthritic cartilage the number of CD36 immunostained chondrocytes is significantly increased.

Comparison of low-field (0.2 Tesla) and high-field (1.5 Tesla) magnetic resonance imaging of the knee joint.

In order to evaluate the reliability of low-field magnetic resonance imaging (MRI), we examined 22 patients using a 0.2-Tesla magnet unit in comparison with a 1.5-Tesla system. The MRI findings were compared with the intraoperative findings. Concerning the diagnosis of meniscal tears, the gradings of both systems differed only in three cases. The specificity was 97% (both systems), the sensitivity 83% (1.5 T) versus 75% (0.2 T). The sensitivity and specificity for detection of tears of the anterior cruciate ligament were 100% and 75%, respectively, for both systems. The gradings differed only in two cases. In our series we found 6 full-thickness cartilage defects that were all detected with the high-field imaging system. They were missed by the low-field imaging system in 5 cases. The results suggest that both systems are reliable in diagnosing meniscal tears and ruptures of the anterior cruciate ligament.

Cartilage thickness measurement in magnetic resonance imaging

To assess the accuracy of cartilage thickness measurements in magnetic resonance imaging (MRI), we compared data obtained by cartilage thickness measurements in MRI with corresponding histological sections of 14 human proximal tibial articular surfaces. Each proximal tibial articular surface was cut into five medial and lateral slices and each of these slices was divided into three sectors providing 420 sectors, 406 of which were evaluated in our study. The overall correlation coefficient (r) was 0.96. Topographical differences were found. The lowest correlation coefficient in our series was observed in the anterior part of the medial tibial plateau (r = 0.88). Cartilage thickness measurements in MRI were more accurate in cartilage thicker than 2 mm (r = 0.94) than in thinner cartilage layers (r = 0.73). There were no significant differences in cartilage thickness measurements in different grades of osteoarthritis. However, the mean percentage difference between cartilage thickness in MRI and histology was about 10% in our series.

Progression von Fußdeformitäten bei rheumatoider Arthritis – Eine radiologische Verlaufsbeobachtung über fünf Jahre

ZusammenfassungEinleitung: Die typischen Fußveränderungen bei Patienten mit rheumatoider Arthritis (RA) sind der Rückfußvalgus, die Abflachung des Längsgewölbes sowie der Spreizfuß mit Ausbildung eines Hallux valgus und Deformitäten der Kleinzehen. Diese Fußdeformitäten stören den Patienten weniger kosmetisch, sondern schränken ihn vor allem schmerzbedingt in seiner Gehfähigkeit ein. Methoden: Anhand von standardisierten Röntgenaufnahmen von 70 Füßen bei 36 Patienten mit gesicherter RA bei einer durchschnittlichen Erkankungsdauer von 19,2 Jahren (±9,8 Jahre) konnte die Progression der Fußdeformitäten im Verlauf von fünf Jahren dargestellt werden. Zur Auswertung wurde der Index nach Larsen, Dale und Eek herangezogen und entsprechend die Anzahl der befallenen Gelenke sowie ihre Prädilektion ausgewertet. Ebenso wurde die Vorfußbreite und das Längsgewölbe vermessen. Ergebnisse: Das Großzehengrundgelenk war im Rahmen der Nachuntersuchung mit 57% am häufigsten befallen. Des weiteren zeigten vor allem die Tarsometatarsalgelenke der Lisfranc‘schen Gelenklinie progressive Veränderungen. Insgesamt zeigte sich eine radiologische Progression der Deformitäten mit Veränderung der Fußstatik bei 97% der Patienten. Schlußfolgerung: Bei der raschen Progression von Fußdeformitäten bei RA bedarf es zusäztlich zur medikamentösen Therapie einer konsequenten Kontrolle des Fußbefundes verbunden mit einer stadien- und beschwerdeorientierten Behandlung.SummaryObjective: The typical changes of the foot in patients with rheumatoid arthritis (RA) are the rear foot valgus and the flattening of the longitudinal arch as well as the splayfoot with hallux valgus and little toe deformities. These foot deformities are not so much a cosmetic problem, but are very painful and limit the patient‘s mobility. Methodes: The progression of rheumatic foot deformities with a follow-up of five years was described in 36 patients (70 feet) with RA and an average duration of the disease of 19.2 years (±9.8 years). The analysis was based on standardized X-rays of the feet using the index of Larsen, Dale, and Eek. The number of affected joints and their predominant locations were evaluated. Results: In the course of the follow-up, the first MTP joint was affected most frequently in 57%. Especially the tarsometatarsal joints of the Lisfranc-joint-line showed progressive changes. Altogether, a radiological progression of arthritic changes and a worsening of the foot statics were observed in 97% of the patients. Conclusion: In view of the rapid progression of rheumatic foot disorders, there is need not only for a consequent pharmacotherapy but also for strict clinical controls and a disease stage oriented local therapy.

Empfehlungen der EULAR zur behandlung der gonarthrose. Bericht einer kommission des "Standing Committee for International Clinical Studies Including Therapeutic Trials (ESCISIT)"

Background: Osteoarthritis (OA) is the most common joint disease encountered throughout Europe. A task force for the EULAR standing committee for clinical trials met in 1998 to determine the methodological and logistical approach required for the development of evidence-based guidelines for treatment of knee OA. The guidelines were restricted to cover all currently available therapies for knee OA diagnosed either clinically and/or radiographically affecting any compartment of the knee. Methods: The first stage was the selection of treatment modalities to be considered. The second stage comprised a search of the electronic databases Medline and Embase using a combination of subject headings and key words. All European language publications in the form of systematic reviews, meta-analyses, randomized-controlled trials, controlled trials and observational studies were included. During stage three all of the relevant studies were quality scored. The summary statistics for validated outcome measures, when available, were recorded and where practical the numbers needed to treat (NNT) and the effect size (ES) for each therapy was calculated. The fourth stage involved determination of key clinical propositions by expert consensus employing a Delphi approach. The final stage involved ranking of these propositions according to the available evidence. A second set of propositions relating to a future research agenda was determined by expert consensus using a Delphi approach. Results: Over 2400 English language publications and 400 non-English language publications were identified. Seven hundred and forty four studies presented outcome data of the effects of specific treatments on knee OA. Quantitative analysis of treatment effect was possible in only 61 studies. Recommendations for the management of knee OA based on currently available data and expert opinion are presented. Proposals for a future research agenda are highlighted. Conclusions: These are the first clinical guidelines on knee OA to combine an evidence-based approach and a consensus approach across a wide range of treatment modalities. It is apparent that only certain clinical propositions are supported by substantial research-based evidence, while others are not. There is thus an urgent need for future well designed trials to address key clinical questions. (Less)