Hans-Dieter Carl

Chondromodulin 1 stabilizes the chondrocyte phenotype and inhibits endochondral ossification of porcine cartilage repair tissue

OBJECTIVE To investigate the effect of chondromodulin 1 on the phenotype of osteochondral progenitor cells in cartilage repair tissue. METHODS Self-complementary adeno-associated virus (AAV) vectors carrying chondromodulin 1 complementary DNA (AAV-Chm-1) were applied to cartilage lesions in the knee joints of miniature pigs that were treated by the microfracture technique. Alternatively, isolated porcine osteochondral progenitor cells were infected with AAV-Chm-1 or with AAV-GFP control vectors ex vivo prior to being transplanted into cartilage lesions in which the subchondral bone plate was left intact. The quality of the repair tissue and the degree of endochondral ossification were assessed by histochemical and immunohistochemical methods. The effects of chondromodulin 1 overexpression were also analyzed by angiogenesis assays and quantitative reverse transcriptase-polymerase chain reaction. RESULTS AAV-Chm-1-infected cells efficiently produced chondromodulin 1, which had strong antiangiogenic effects, as verified by the inhibition of tube formation of endothelial cells. Gene expression analyses in vitro revealed the cell cycle inhibitor p21WAF1/Cip1 as one target up-regulated by AAV-Chm-1. Direct application of AAV-Chm-1 vectors into microfractured porcine cartilage lesions stimulated chondrogenic differentiation of ingrowing progenitor cells, but significantly inhibited terminal chondrocyte hypertrophy, the invasion of vessel structures, and excessive endochondral ossification, which were otherwise observed in untreated lesions. Indirect gene transfer, with infection of porcine osteochondral progenitor cells by AAV-Chm-1 ex vivo, also supported chondrogenic differentiation of these transplanted cells. AAV-Chm-1-infected cells maintained a chondrocyte-like phenotype and formed a hyaline-like matrix that was superior to that formed by uninfected or AAV-GFP-infected cells. CONCLUSION Our findings indicate that the antiangiogenic factor chondromodulin 1 stabilizes the chondrocyte phenotype by supporting chondrogenesis but inhibiting chondrocyte hypertrophy and endochondral ossification.

Molecular differentiation between osteophytic and articular cartilage – clues for a transient and permanent chondrocyte phenotype

OBJECTIVE To identify the molecular differences between the transient and permanent chondrocyte phenotype in osteophytic and articular cartilage. METHODS Total RNA was isolated from the cartilaginous layer of osteophytes and from intact articular cartilage from knee joints of 15 adult human donors and subjected to cDNA microarray analysis. The differential expression of relevant genes between these two cartilaginous tissues was additionally validated by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and by immunohistochemistry. RESULTS Among 47,000 screened transcripts, 600 transcripts were differentially expressed between osteophytic and articular chondrocytes. Osteophytic chondrocytes were characterized by increased expression of genes involved in the endochondral ossification process [bone gamma-carboxyglutamate protein/osteocalcin (BGLAP), bone morphogenetic protein-8B (BMP8B), collagen type I, alpha 2 (COL1A2), sclerostin (SOST), growth arrest and DNA damage-induced gene 45ß (GADD45ß), runt-related transcription factor 2 (RUNX2)], and genes encoding tissue remodeling enzymes [matrix metallopeptidase (MMP)9, 13, hyaluronan synthase 1 (HAS1)]. Articular chondrocytes expressed increased transcript levels of antagonists and inhibitors of the BMP- and Wnt-signaling pathways [Gremlin-1 (GREM1), frizzled-related protein (FRZB), WNT1 inducible signaling pathway protein-3 (WISP3)], as well as factors that inhibit terminal chondrocyte differentiation and endochondral bone formation [parathyroid hormone-like hormone (PTHLH), sex-determining region Y-box 9 (SOX9), stanniocalcin-2 (STC2), S100 calcium binding protein A1 (S100A1), S100 calcium binding protein B (S100B)]. Immunohistochemistry of tissue sections for GREM1 and BGLAP, the two most prominent differentially expressed genes, confirmed selective detection of GREM1 in articular chondrocytes and that of BGLAP in osteophytic chondrocytes and bone. CONCLUSIONS Osteophytic and articular chondrocytes significantly differ in their gene expression pattern. In articular cartilage, a prominent expression of antagonists inhibiting the BMP- and Wnt-pathway may serve to lock and stabilize the permanent chondrocyte phenotype and thus prevent their terminal differentiation. In contrast, osteophytic chondrocytes express genes with roles in the endochondral ossification process, which may account for their transient phenotype.

Assessment of Plantar Pressure in Forefoot Relief Shoes of Different Designs

Background: After reconstructive forefoot surgery, patients require complete or partial forefoot relief, which can be obtained with a variety of shoe designs. The aim of this study was to evaluate the effectiveness of two different types of forefoot-relief shoes frequently used after surgery, especially their safety against unintentional forefoot load. Methods: Ten healthy volunteers were asked to perform five trials on a treadmill at self-selected speeds. In the first trial, mean peak pressure values in mass-produced shoes and insoles were evaluated and considered as 100%. Two different shoe designs (short heel – short sole, ii: short heel – complete sole) were compared in two trials each with appropriate and inappropriate use (attempting to put weight on the forefoot) gait pattern. Plantar pressure values were obtained using the Pedar® cable system (Novel Inc., Munich, Germany). For analysis, pedobarographic pictures were subdivided into midfoot (31% to 60% of the total insole length) and forefoot (61% to 100% of the total insole length). ANOVA was used for statistical analysis, and p values less than 0.01 were considered significant. Results: With the short-soled shoe, forefoot and midfoot relief was 100% in both compliant and in noncompliant use. With wearing a complete sole, compliant use led to a significant reduction (p < 0.01) of mean peak pressure under the forefoot (34 ± 13% remaining) and midfoot (47 ± 13% remaining). Noncompliant use of the complete-sole shoe produced mean peak pressure values significantly higher (p < 0.01) than normal gait in mass produced shoes under the forefoot, but not under the midfoot. Conclusions: Forefoot-relief shoes are effective in reducing both mean and peak plantar pressures. Shoes with a nonsupported midfoot and forefoot may be safer with inappropriate use than shoes with a complete sole. The kind of forefoot shoe should be carefully chosen to regulate weightbearing after reconstructive forefoot surgery.

Limited evidence of chondrocyte outgrowth from adult human articular cartilage

OBJECTIVE Cellular outgrowth from articular cartilage tissue has been described in a number of recent experimental studies. The aim of this study was to investigate the occurrence of cellular outgrowth from articular cartilage explants isolated from adult human donors. METHOD Macroscopically intact articular cartilage specimens were isolated from adult human donors and cultured either in their native status, or in a cleansed status achieved by forced washing to minimize attaching cells. Additionally, the effect of chemotactic stimuli including cell lysate, High-Mobility-Group-Protein B1 (HMGB-1), Trefoil-factor 3 (TFF3), bone morphogenetic protein-2 (BMP-2), transforming growth factor-ß1 (TGF-ß1), or three-dimensional fibrin or collagen matrices were investigated. Co-cultures with synovial membrane served as a positive control for a source of migratory cells. The occurrence of cellular outgrowth was analyzed by histological examination after a culture period of 4 weeks. RESULTS Spontaneous cellular outgrowth from cleansed cartilage specimens was not observed at a relevant level and could not significantly be induced by chemotactic stimuli or three-dimensional matrices either. A forming cartilage-adjoining cell layer was only apparent in the case of native cartilage explants with cellular remnants from surgical isolation or in co-culture experiments with synovial membrane. CONCLUSION The relevance of cellular outgrowth from cartilage tissue is largely absent in the case of adult human articular cartilage samples. A cartilage-adjoining cell layer forming around the explants may instead originate from still attaching cells that remained from surgical isolation.

Soccer boots elevate plantar pressures in elite male soccer professionals.

Objective:The present study measured the difference in peak plantar pressure between running shoes and soccer shoes in male soccer professionals [mean (SD): age, 23 (4) years; height, 184 (7) cm; weight, 81 (6) kg]. Design:Case series. Setting:Institutional study. Participants:A total of 17 elite male soccer professionals [mean (SD): age, 23 (4) years; height, 184 (7) cm; weight 81 (6) kg]. Interventions:Fifteen right and left steps with sensor-loaded insoles (99 sensors, 50 Hz) while running (3.3 m/s) in running shoes and then chosen soccer shoes (12-stud profile). The players were equipped with running shoes from the supplier without any medical supervision. Main Outcome Measures:Changes of peak plantar pressure for 9 defined foot portions between soccer boots and running shoes. Results:A statistically significant increase of peak plantar pressure was found for the lateral midfoot (P < 0.001 for preferred and nonpreferred foot), the first metatarsal head (preferred foot: P < 0.001, nonpreferred foot: P = 0.002), the metatarsal heads 4/5 (preferred foot: P = 0.001, nonpreferred foot: P = 0.002), and the big toe (preferred foot: P = 0.001, nonpreferred foot: P < 0.001), but not for the lateral and medial hindfoot, the medial midfoot, and lesser toes. Conclusions:In running, soccer boots generate excessive foot loadings predominantly under the lateral midfoot, as compared with running shoes. Players should be trained with a thoughtfully designed workout regimen that allows performing as many straight running exercises as possible in running shoes instead of soccer boots. This may help to prevent fifth metatarsal stress fractures in elite male soccer players.

Synovektomie der großen Gelenke in der Ära der Biologika

Since the mid 1980s, a global decrease in surgical procedures related to rheumatoid arthritis (RA) has been documented for joint-preserving procedures such as synovectomy as well as joint replacement surgery. This reflects improvements in the early management of rheumatoid arthritis and availability of more effective medical treatment. The present review summarizes the recent literature on the frequency of orthopaedic surgery in RA patients as well as the role of synovectomy in the rheumatoid hip, knee and shoulder in times of biological RA therapy.ZusammenfassungSeit Mitte der 1980er Jahre ist ein globaler Rückgang an operativen Eingriffen für Patienten mit rheumatoider Arthritis (RA) zu verzeichnen, sowohl für gelenkerhaltende Eingriffe wie Synovektomien als auch für Gelenkersatzoperationen. Die Ursachen hierfür liegen in einer früheren Erkennung der Erkrankung sowie vor allem der Verfügbarkeit effektiver medikamentöser Therapieoptionen. Der Artikel fasst im allgemeinen Teil die aktuelle Datenlage zu den rheumachirurgischen Eingriffen in der Ära der biologischen Therapieprinzipien zusammen. Der spezielle Teil diskutiert den Stellenwert der Synovektomie der großen Gelenke (Hüftgelenk, Kniegelenk, Schultergelenk) unter besonderer Berücksichtigung der Biologika-Therapie.AbstractSince the mid 1980s, a global decrease in surgical procedures related to rheumatoid arthritis (RA) has been documented for joint-preserving procedures such as synovectomy as well as joint replacement surgery. This reflects improvements in the early management of rheumatoid arthritis and availability of more effective medical treatment. The present review summarizes the recent literature on the frequency of orthopaedic surgery in RA patients as well as the role of synovectomy in the rheumatoid hip, knee and shoulder in times of biological RA therapy.

Imaging of osteoarthritis of the peripheral joints

ZusammenfassungSchmerzen und Funktionsstörungen sind die klinischen Zeichen einer Arthrose. Letztlich wird die Diagnose durch das konventionelle Röntgenbild gesichert, und es werden wertvolle Hinweise für die Differenzialdiagnose gewonnen. Für die Verlaufskontrolle der Arthrose werden Röntgenaufnahmen in größeren zeitlichen Abständen bei Beschwerdezunahme und Therapieresistenz erforderlich, meist beim Übergang von konservativen zu operativen Verfahren. Besondere Vorteile sind weltweite Verfügbarkeit, Kostengünstigkeit, jahrzehntelange Erfahrung mit der Methode, Archivierbarkeit über lange Zeiträume. Die typischen Arthrosebefunde im konventionellen Röntgenbild werden durch quantifizierte Messmethoden eher grob erfasst. In vielen Fällen korreliert der radiologische Arthrosegrad nur ungenügend mit der klinischen Symptomatik.Radiologische Veränderungen gehören zur Klassifikation der Arthrose nach ACR-Kriterien (an Hüfte, Hand und Knie). Mit dem konventionellen Röntgenbild lässt sich der Knochen mit hoher örtlicher Auflösung besser darstellen als mit allen anderen bildgebenden Verfahren. Weichteile und Knorpel können nur indirekt beurteilt werden. Die Gelenksonographie kann bei der Arthrose die intraartikuläre Ergussbildung frühzeitiger erfassen sowie das Ausmaß der osteochondrophytären Ausziehungen und der synovialen Beteiligung bildlich darstellen. Vor allem an Hüft-, Schulter- und Kniegelenken können begleitende Veränderungen der Sehnen, Bursen und faserknorpeligen Strukturen beurteilt werden. Stärke der MRT ist die Fähigkeit, den Knorpel hinsichtlich Volumen und struktureller Veränderungen direkt sichtbar zu machen. Durch geeignete Wahl der Parameter können selbst innerhalb des Knorpels gelegene pathologische Veränderungen sichtbar gemacht werden, auch wenn eine qualitative Darstellung des hyalinen Knorpels bislang nicht eindeutig validiert ist. Die Knochenszintigraphie vermag entzündlich-rheumatische Veränderungen von degenerativen abzugrenzen, kann aktivierte von inaktiven Gelenken unterscheiden und kann wertvolle Informationen über die subchondrale Knochenaktivität geben, die sich ggf. bei weiterer Evaluierung zu einem Prognosemarker entwickeln kann.In dieser Übersicht werden Empfehlungen der „Kommission Bildgebende Verfahren“ zu technischen und personellen Voraussetzungen, der Indikationsstellung sowie der praktischen Durchführung gegeben und die bei der Arthrose zu erwartenden Befunde kurz dargestellt.AbstractPain and loss of function are the clinical signs of osteoarthritis (OA). Conventional x-rays confirm the diagnosis or provide important hints for differential diagnosis. In the natural course of OA, x-rays are performed at longer intervals when pain increases or therapy is without effect, especially if more invasive therapies, or even surgery, becomes necessary. The advantages of x-rays are worldwide availability, cost effectiveness, very long experience with this imaging method and the possibility of storing the images for long periods of time. The typical findings of OA can be detected only roughly by quantitative methods. In many patients, grading of OA does not correlate well with the clinical symptoms.X-ray changes are part of the American College of Rheumatology (ACR) classification criteria for OA of the hand, hip and knee. Ordinary s-rays can depicting bone with a higher local resolution than any other imaging technique. Soft tissues and cartilage can be visualized only indirectly.In OA, ultrasound is the method to depict intra-articular effusion at an early stage. Osteophytes or the degree of synovitis are also visible. Concomitant changes in tendons, bursae or cartilage, such as structures in the hip, shoulder and knee, can be evaluated.MRI is an appropriate tool for describing changes in cartilage volume and concomitant soft-tissue alterations. For qualitative cartilage imaging, MRI has, to date, not been fully validated.Bone scans (bone scintigraphy) allow the differentiation of inflammatory from degenerative joint affections and may add information on the activity of the subchondral bone, which may develop to a prognostic marker of OA.This survey represents recommendations of the Commission “Imaging Techniques” of the German Rheumatology Society regarding the technical and individual conditions, indications, practical guidance and the typical findings of imaging in OA.

Inaccuracy of a Physical Strain Trainer for the Monitoring of Partial Weight Bearing

OBJECTIVE To investigate the use of a physical strain trainer for the monitoring of partial weight bearing. DESIGN Case series with healthy volunteers. SETTING Orthopedic clinic. PARTICIPANTS Healthy volunteers (N=10) with no history of foot complaints. INTERVENTIONS Volunteers were taught to limit weight bearing to 10% body weight (BW) and 50% BW, monitored by a physical strain trainer. MAIN OUTCOME MEASURES The parameters peak pressure, maximum force, force-time integral, and pressure-time integral were assessed by dynamic pedobarography when volunteers walked with full BW (condition 1), 50% BW (condition 2), and 10% BW (condition 3). RESULTS With 10% BW (condition 3), forces with normative gait (condition 1) were statistically significantly reduced under the hindfoot where the physical strain trainer is placed. All pedobarographic parameters were, however, exceeded when the total foot was measured. A limitation to 10% BW with the physical strain trainer (condition 3) was equal to a bisection of peak pressure and maximum force for the total foot with normative gait (condition 1). Halved BW (condition 2) left a remaining mean 82% of peak pressure and mean 59% of maximum force from full BW (condition 1). CONCLUSIONS The concept of controlling partial weight bearing with the hindfoot-addressing device does not represent complete foot loading. Such devices may be preferably applied in cases when the hindfoot in particular must be off-loaded. Other training devices (eg, biofeedback soles) that monitor forces of the total foot have to be used to control partial weight bearing of the lower limb accurately.

Introduction of a neutral shoe to assess reference values for dynamic pedobarography

Abstract Background: The aim of our study was to introduce a so-called “neutral shoe” as a tool to assess reference values for dynamic pedobarographic investigations. Materials and methods: Twelve healthy volunteers were asked to participate. During the first trial the participants were asked to walk with a neutral shoe (Breidbach, Germany). The second trial was performed with the running shoe “Faas 500” (Puma SE, Germany). Peak plantar pressure values were analyzed from nine foot regions using the Pedar® X system (Novel Inc., Munich, Germany). Results: The mean peak pressure reduction for the total foot was 36% under the left (non-preferred) foot and 32% for the right (preferred) foot. A statistically significant reduction of peak pressure was observed for eight regions, from a mean 14% peak pressure reduction under the right metatarsal head 1 up to a 41% peak pressure reduction under the right big toe. Conclusions: The neutral shoe is a feasible tool to assess reference values for dynamic pedobarography. Such a reference tool may help to standardise several steps in the development and construction of shoes and orthotic devices.

The Transient Chondrocyte Phenotype in Human Osteophytic Cartilage A Role of Pigment Epithelium-Derived Factor?

Objective: To identify factors that are responsible for the phenotypic differences between transient chondrocytes within human osteophytes prone to endochondral ossification and permanent chondrocytes within articular cartilage persisting for decades. Methods: Differential gene expression of chondrocytes from human osteophytes or from articular cartilage was detected by cDNA microarray analysis. The expression of pigment epithelium-derived factor (PEDF), one of the most impressively differentially expressed genes, was validated by quantitative reverse transcriptase polymerase chain reaction as well as immunohistochemistry. The mode of action of PEDF was explored by cell viability assays and by detecting target genes. Results: PEDF mRNA expression was upregulated by 118.5-fold (P = 0.01) in human osteophytic cartilage compared with articular cartilage, which was reflected by strong immunostaining for PEDF in the cartilaginous layer of osteophytes but largely negative staining in articular cartilage. Elevated levels of PEDF in osteophytes were associated with enhanced apoptosis. PEDF increased the expression of the proapoptotic factor FasL and induced cell death in cell culture. Osteochondral progenitor cells were more responsive to PEDF than differentiated articular chondrocytes. Conclusions: The induction of the proapoptotic factor PEDF within the osteophyte cartilage suggests a molecular concept for the transient chondrocyte phenotype that arises from progenitor cells and is prone to terminal differentiation and cell death.