In-hospital and 6-month outcomes in patients with COVID-19 supported with extracorporeal membrane oxygenation (EuroECMO-COVID): a multicentre, prospective observational study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been widely used in patients with COVID-19, but uncertainty remains about the determinants of in-hospital mortality and data on post-discharge outcomes are scarce. The aims of this study were to investigate the variables associated with in-hospital outcomes in patients who received ECMO during the first wave of COVID-19 and to describe the status of patients 6 months after ECMO initiation.

METHODS

EuroECMO-COVID is a prospective, multicentre, observational study developed by the European Extracorporeal Life Support Organization. This study was based on data from patients aged 16 years or older who received ECMO support for refractory COVID-19 during the first wave of the pandemic-from March 1 to Sept 13, 2020-at 133 centres in 21 countries. In-hospital mortality and mortality 6 months after ECMO initiation were the primary outcomes. Mixed-Cox proportional hazards models were used to investigate associations between patient and management-related variables (eg, patient demographics, comorbidities, pre-ECMO status, and ECMO characteristics and complications) and in-hospital deaths. Survival status at 6 months was established through patient contact or institutional charts review. This study is registered with ClinicalTrials.gov, NCT04366921, and is ongoing.

FINDINGS

Between March 1 and Sept 13, 2020, 1215 patients (942 [78%] men and 267 [22%] women; median age 53 years [IQR 46-60]) were included in the study. Median ECMO duration was 15 days (IQR 8-27). 602 (50%) of 1215 patients died in hospital, and 852 (74%) patients had at least one complication. Multiorgan failure was the leading cause of death (192 [36%] of 528 patients who died with available data). In mixed-Cox analyses, age of 60 years or older, use of inotropes and vasopressors before ECMO initiation, chronic renal failure, and time from intubation to ECMO initiation of 4 days or more were associated with higher in-hospital mortality. 613 patients did not die in hospital, and 547 (95%) of 577 patients for whom data were available were alive at 6 months. 102 (24%) of 431 patients had returned to full-time work at 6 months, and 57 (13%) of 428 patients had returned to part-time work. At 6 months, respiratory rehabilitation was required in 88 (17%) of 522 patients with available data, and the most common residual symptoms included dyspnoea (185 [35%] of 523 patients) and cardiac (52 [10%] of 514 patients) or neurocognitive (66 [13%] of 512 patients) symptoms.

INTERPRETATION

Patient's age, timing of cannulation (<4 days vs ≥4 days from intubation), and use of inotropes and vasopressors are essential factors to consider when analysing the outcomes of patients receiving ECMO for COVID-19. Despite post-discharge survival being favourable, persisting long-term symptoms suggest that dedicated post-ECMO follow-up programmes are required.

FUNDING

None.

Acute limb ischemia after femoro-femoral extracorporeal life support implantation: a comparison of surgical, percutaneous or combined vascular access in 402 patients

BACKGROUND

Extracorporeal life support (ECLS) is a salvage treatment for acute circulatory failure. Our high-volume tertiary centre performs more than 100 implants annually and provides ECLS-transports. With this study, we aimed to analyse the incidence and risk factors of limb ischemia depending on the vascular access.

METHODS

Between January 1st 2007 and December 31st 2018, 937 patients received an ECLS. Preoperative, intraoperative, in-hospital and up to 5 years follow-up data was collected. Outcome measures were limb ischemia and survival.

RESULTS

In total, 402 femoro-femoral veno-arterial ECLS patients were identified. Mean age was 56±16.7years, 26.9% were female, 7.9% had a history of peripheral vascular disease. Cannulation was performed percutaneously in 82.1% (n=330), surgically in 5.7% (n=23) and combined in 12.2% (n=49). Mortality was not significantly different between the groups (51.1% percutaneous, 43.5% surgical, 44.9% combined (p=0.89)). There was no significant difference in limb ischemia either, but a trend towards an increased frequency in the percutaneous group (p=0.0501). No amputation was necessary. Limb ischemia slightly increased in-hospital mortality (54.6%) but did not affect long-term survival beyond 30 days. Univariate analysis adjusted for cannulation methods revealed younger age and female gender as risk factors of limb ischemia and younger age for limb ischemia after percutaneous cannulation.

CONCLUSIONS

Our study shows that percutaneous, surgical and combined vascular access techniques for ECLS implantation are associated with comparable and low incidence of limb ischemia which slightly increases in-hospital mortality. Special precaution has to be taken in young and female patients.

OP0200 BLOCKING ROR2 IMPROVES CARTILAGE INTEGRITY AND PROVIDES PAIN RELIEF IN OSTEOARTHRITIS

Background:

Osteoarthritis (OA) is the leading cause of chronic disability worldwide, affecting 12% of the population, and yet we still do not have a disease-modifying treatment. Cartilage breakdown is the hallmark of OA, and patients suffer from pain and loss of joint function/independence, severely affecting quality of life. Therefore, there is a huge unmet clinical need.

Receptor tyrosine kinase–like orphan receptor 2 (ROR2) is a non-canonical WNT receptor that regulates the planar cell polarity pathway, controlling limb outgrowth during development. During skeletal development, chondrocytes require ROR2 to undergo hypertrophy throughout the process of endochondral bone formation1. Loss of function mutations in humans causes Recessive Robinow Syndrome, leading to limb shortening and brachydactyly2,3.

Although absent from healthy adult articular cartilage, our initial studies identified high expression levels of ROR2 in chondrocytes from patients with OA, suggesting a role in the disease process

Objectives:

To test the potential of ROR2 blockade as a disease-modifying treatment for OA.

Methods:

Human cartilage organoid model in nude mice, menisco-ligament injury (MLI) model of OA in mice, behavioural studies, in vitro studies in cells.

Results:

ROR2/WNT5A signaling was increased in osteoarthritic cartilage. Blocking ROR2 was sufficient to induce articular chondrogenesis and suppress expression of aggrecanases in a mesenchymal stem cell line, and to support cartilage formation in a human cartilage organoid model in nude mice using primary chondrocytes from patients with OA.

In the MLI model of OA, blocking ROR2 in therapeutic regime using atelocollagen-conjugated siRNA resulted in reduced cartilage destruction and in rapid and sustained pain relief. Due to the limited expression pattern of ROR2 in adulthood, no systemic or local toxicity were expected, nor were any observed4.

With the current technology, ROR2 blockade requires intra-articular (IA) injections of siRNA conjugated to atelocollagen every 5 days. Preliminary efficacy data of potentially longer-acting ROR2 blockers are promising.

The mechanism of action of ROR2 blockade was independent of modulation of canonical WNT signaling.

ROR2/WNT5A promoted nuclear localization of YAP, which required both Rho and G-proteins. YAP signaling downstream of ROR2 also required Rho, but not G-proteins. YAP and TEAD inhibition was required, but not sufficient, for the chondrogenic effect of blocking ROR2. Therefore, additional, yet unknown mechanisms must be involved downstream of ROR2.

Conclusion:

ROR2 blockade has potential as a disease-modifying treatment for OA, resulting in cartilage protection and rapid and sustained pain relief in a murine model. This will be crucial for clinical success of any treatment for OA and promote patient compliance.

Our current siRNA-atelocollagen based technology requires IA injections too frequently to be acceptable for patients. We are developing ROR2 blockade which can be administered systemically or IA not more often than every 3 months - work funded by FOREUM.

References:

[1]DeChiara, T. M. et al. Ror2, encoding a receptor-like tyrosine kinase, is required for cartilage and growth plate development. Nat. Genet.24, 271–4 (2000).

[2]Bokhoven, H. Van, Celli, J. & Kayserili, H. Mutation of the gene encoding the ROR2 tyrosine kinase causes autosomal recessive Robinow syndrome. Nature25, 423–426 (2000).

[3]Afzal, A., Rajab, A., Fenske, C. & Oldridge, M. Recessive Robinow syndrome, allelic to dominant brachydactyly type B, is caused by mutation of ROR2. Nature25, 419–422 (2000).

[4]Thorup, A.-S. et al. ROR2 blockade as a therapy for osteoarthritis. Sci. Transl. Med.12, eaax3063 (2020).

Acknowledgements:

We gratefully acknowledge funding support of this work by the Medical College of St Bartholomew’s Hospital Trust, the William Harvey Research Foundation, FOREUM foundation for research in rheumatology (1016807), the MRC (MR/L022893/1, MR/N010973/1, MR/P026362/1, MR/K013076/1), Versus Arthritis (21515, 20886, 21621, 20859), and the DFG Emmy-Noether program (BE4328/5-1).

Disclosure of Interests:

Anne-Sophie Thorup: None declared, Danielle Strachan: None declared, Sara Caxaria: None declared, Blandine Poulet: None declared, Bethan Thomas: None declared, Suzanne Eldridge: None declared, Giovanna Nalesso: None declared, James Whiteford: None declared, Costantino Pitzalis: None declared, Thomas Aigner: None declared, Roger Corder: None declared, Jessica Bertrand: None declared, Francesco Dell’Accio Consultant of: Samumed and UCB

3D ultrasound biomicroscopy for assessment of cartilage repair tissue: volumetric characterisation and correlation to established classification systems

Objective and sensitive assessment of cartilage repair outcomes lacks suitable methods. This study investigated the feasibility of 3D ultrasound biomicroscopy (UBM) to quantify cartilage repair outcomes volumetrically and their correlation with established classification systems. 32 sheep underwent bilateral treatment of a focal cartilage defect. One or two years post-operatively the repair outcomes were assessed and scored macroscopically (Outerbridge, ICRS-CRA), by magnetic resonance imaging (MRI, MOCART), and histopathology (O'Driscoll, ICRS-I and ICRS-II). The UBM data were acquired after MRI and used to reconstruct the shape of the initial cartilage layer, enabling the estimation of the initial cartilage thickness and defect volume as well as volumetric parameters for defect filling, repair tissue, bone loss and bone overgrowth. The quantification of the repair outcomes revealed high variations in the initial thickness of the cartilage layer, indicating the need for cartilage thickness estimation before creating a defect. Furthermore, highly significant correlations were found for the defect filling estimated from UBM to the established classification systems. 3D visualisation of the repair regions showed highly variable morphology within single samples. This raises the question as to whether macroscopic, MRI and histopathological scoring provide sufficient reliability. The biases of the individual methods will be discussed within this context. UBM was shown to be a feasible tool to evaluate cartilage repair outcomes, whereby the most important objective parameter is the defect filling. Translation of UBM into arthroscopic or transcutaneous ultrasound examinations would allow non-destructive and objective follow-up of individual patients and better comparison between the results of clinical trials.

A novel MSC-seeded triphasic construct for the repair of osteochondral defects

Mesenchymal stem cells (MSC) are increasingly replacing chondrocytes in tissue engineering based research for treatment of osteochondral defects. The aim of this work was to determine whether repair of critical-size chronic osteochondral defects in an ovine model using MSC-seeded triphasic constructs would show results comparable to osteochondral autografting (OATS). Triphasic implants were engineered using a beta-tricalcium phosphate osseous phase, an intermediate activated plasma phase, and a collagen I hydrogel chondral phase. Autologous MSCs were used to seed the implants, with chondrogenic predifferentiation of the cells used in the cartilage phase. Osteochondral defects of 4.0 mm diameter were created bilaterally in ovine knees (n = 10). Six weeks later, half of the lesions were treated with OATS and half with triphasic constructs. The knees were dissected at 6 or 12 months. With the chosen study design we were not able to demonstrate significant differences between the histological scores of both groups. Subcategory analysis of O'Driscoll scores showed superior cartilage bonding in the 6-month triphasic group compared to the autograft group. The 12-month autograft group showed superior cartilage matrix morphology compared to the 12-month triphasic group. Macroscopic and biomechanical analysis showed no significant differences at 12 months. Autologous MSC-seeded triphasic implants showed comparable repair quality to osteochondral autografts in terms of histology and biomechanical testing.

Micromass co-culture of human articular chondrocytes and human bone marrow mesenchymal stem cells to investigate stable neocartilage tissue formation in vitro

Cell therapies for articular cartilage defects rely on expanded chondrocytes. Mesenchymal stem cells (MSC) represent an alternative cell source should their hypertrophic differentiation pathway be prevented. Possible cellular instruction between human articular chondrocytes (HAC) and human bone marrow MSC was investigated in micromass pellets. HAC and MSC were mixed in different percentages or incubated individually in pellets for 3 or 6 weeks with and without TGF-beta1 and dexamethasone (±T±D) as chondrogenic factors. Collagen II, collagen X and S100 protein expression were assessed using immunohistochemistry. Proteoglycan synthesis was evaluated applying the Bern score and quantified using dimethylmethylene blue dye binding assay. Alkaline phosphatase activity (ALP) was detected on cryosections and soluble ALP measured in pellet supernatants. HAC alone generated hyaline-like discs, while MSC formed spheroid pellets in ±T±D. Co-cultured pellets changed from disc to spheroid shape with decreasing number of HAC, and displayed random cell distribution. In -T-D, HAC expressed S100, produced GAG and collagen II, and formed lacunae, while MSC did not produce any cartilage-specific proteins. Based on GAG, collagen type II and S100 expression chondrogenic differentiation occurred in -T-D MSC co-cultures. However, quantitative experimental GAG and DNA values did not differ from predicted values, suggesting only HAC contribution to GAG production. MSC produced cartilage-specific matrix only in +T+D but underwent hypertrophy in all pellet cultures. In summary, influence of HAC on MSC was restricted to early signs of neochondrogenesis. However, MSC did not contribute to the proteoglycan deposition, and HAC could not prevent hypertrophy of MSC induced by chondrogenic stimuli.

Terminology of osteoarthritis cartilage and bone histopathology - a proposal for a consensus

Unifying terminology used to describe morphologic features is a very important endeavour to assure comparability of work and papers on osteoarthritis animal models. In this editorial an attempt is presented to define and unify the terminology of the macroscopic and histological description of joint changes in OA for both human OA and the OA animal models.

Basic methods in histopathology of joint tissues

Histological and histochemical methods are important tools in the evaluation of joint tissue samples for degenerative joint diseases, both in humans and in animal models. In this respect, standardized, simple, and reliable techniques are mandatory. This chapter describes five basic staining procedures appropriate for macroscopic (Indian ink) and histologic (HE/hematoxylin - eosin) visualization and scoring of cartilage proteoglycan and collagen content (toluidine blue/safranin O and picrosirius red/Goldner's trichrome).

Histopathology atlas of animal model systems - overview of guiding principles

Animal model systems represent an important adjunct and surrogate for studies of osteoarthritis (OA) in humans. They provide a means to study OA pathophysiology as well as aid in the development of therapeutic agents and biological markers for diagnosing and prognosing the disease. Thus, it is of great importance for the OA scientific community, both in academic as well as industrial research, to standardize scoring systems for evaluating the OA disease process and to make results between different studies comparable. The task of the histopathology initiative of OARSI was to achieve a consensus of scoring systems for the most important species used in OA animal model research (dog, guinea pig, horse, mouse, rabbit, rat, and sheep/goat), which are presented in the various chapters in this special volume of Osteoarthritis & Cartilage together with extra chapters on basic methodology (histochemistry, statistics, morphometry), the specific terminology and a general discussion of animal models in OA research. Standardized definitions are suggested for basic but essential terms such as "grading" and "staging" in order to promote their consistent use and thereby promote improved understanding and data interpretation across all model systems. Thus, this introductory chapter presents an overview of the guiding principles for assessment of important OA animal model systems. Use of such systems, independently or in conjunction with other systems in parallel, should facilitate comparability of results across animal model studies.

[Nora's lesion. Discussion of a rare bone proliferation]

Nora's lesion, also known as "bizarre parosteal osteochondromatous proliferation" (BPOP), was first described in 1983 by the pathologist Nora. This lesion is defined as a proliferation of the bone. In most cases the lesion emanates from the intact cortical substance of short bones. It used to be assigned to reactive, heterotopic ossifications. More recent publications described constant genetic alterations supposing a tumorous genesis. Nora lesions are mostly found in the third or fourth decade of life; a preference of sexes is not described in the literature. They are characterized by a typical appearance in radiological diagnostics, but the diagnosis is ultimately determined by histopathological examination. Surgical resection is the therapy of choice.We report the case of a 29-year-old patient with an undetermined proliferation of the proximal ulna. The diagnosis of a Nora's lesion was made. The therapeutic approach, differential diagnosis and corresponding literature are presented and discussed.

Targets to tackle--the pathophysiology of the disease

Osteoarthritis, the degeneration of the joints, is the leading source of physical disability with severely impaired quality of life due to pain and loss of joint functioning in industrialized nations. Clinically, degeneration affects mostly the large weight bearing joints of the legs like the hip or the knees, but in principle it can affect any joint of the body. Osteoarthritis represents a disease group with disease subsets that have different underlying pathophysiological mechanisms. Therefore primary osteoarthritis has to be distinguished from secondary forms of the disease, which are due to traumatic events, endocrine or metabolic disorders etc. The enormous frequency of this disease makes osteoarthritis one of the most expensive conditions in the Western world, both in terms of direct as well as indirect costs. So far, despite intensive efforts over several decades, the success of disease-modifying approaches have been rather limited and mostly restricted to analgesis and non-pharmacologic therapy (e.g. nonsteroidal anti-inflammatory agents, exercise, and physiotherapy). Joint replacement is still the unsurpassed therapy for the symptomatic relief of advanced and incapacitating OA. It is evident that there is a great need for the development of disease modifying agents in order to improve quality of life as well as to relieve the community of the enormous socio-economic burden of the disease.

Ectopic Cushing's syndrome caused by a well differentiated ACTH-secreting neuroendocrine carcinoma of the ileum

Cushing's syndrome can be caused by adrenocorticotropic hormone-secreting solid tumors. We report a rare case of an ileal endocrine carcinoma that produced ACTH and induced hypercortisolism. A now 47-year-old man presented at age 41 with weight gain, tremor, perspiration, and general fatigue. Laboratory testing showed hypercortisolism and diabetes mellitus. Further examinations revealed ectopic Cushing's syndrome. The search for the primary tumor was difficult. The patient underwent subtotal thyroidectomy and surgical removal of a pituitary lesion. After resection of an ACTH-producing metastasis of the mesentery, temporary remission of Cushing's syndrome ensued. At the age 45 the primary tumor was detected in the ileum by Ga-68 DOTATOC-PET scan and explorative laparotomy. After surgical removal of this well differentiated neuroendocrine carcinoma the patient significantly improved clinically. He experienced better blood pressure and remission of his diabetes mellitus in addition to increased muscular strength. Endocrine laboratory testing at follow-up examinations confirmed remission of hypercortisolism and diabetes mellitus. A Ga-68 DOTATOC PET scan and a 1 mg dexamethasone suppression test 5 months after surgery showed normal results. Ectopic ACTH secretion within the small bowel is very rare. This case underscores the difficulty in locating the source of ectopic ACTH secretion and suggests using small bowel barium study, tubus endoscopy or video endoscopy for preoperative localization if the small bowel is suspected as tumor source.

Perilesional changes of focal osteochondral defects in an ovine model and their relevance to human osteochondral injuries

Perilesional changes of chronic focal osteochondral defects were assessed in the knees of 23 sheep. An osteochondral defect was created in the main load-bearing region of the medial condyle of the knees in a controlled, standardised manner. The perilesional cartilage was evaluated macroscopically and biopsies were taken at the time of production of the defect (T0), during a second operation one month later (T1), and after killing animals at three (T3; n = 8), four (T4; n = 8), and seven (T7; n = 8) months. All the samples were histologically assessed by the International Cartilage Repair Society grading system and Mankin histological scores. Biopsies were taken from human patients (n = 10) with chronic articular cartilage lesions and compared with the ovine specimens. The ovine perilesional cartilage presented with macroscopic and histological signs of degeneration. At T1 the International Cartilage Repair Society ‘Subchondral Bone’ score decreased from a mean of 3.0 (sd 0) to a mean of 1.9 (sd 0.3) and the ‘Matrix’ score from a mean of 3.0 (sd 0) to a mean of 2.5 (sd 0.5). This progressed further at T3, with the International Cartilage Repair Society ‘Surface’ grading, the ‘Matrix’ grading, ‘Cell Distribution’ and ‘Cell Viability’ grading further decreasing and the Mankin score rising from a mean of 1.3 (sd 1.4) to a mean of 5.1 (sd 1.6). Human biopsies achieved Mankin grading of a mean of 4.2 (sd 1.6) and were comparable with the ovine histology at T1 and T3.

The perilesional cartilage in the animal model became chronic at one month and its histological appearance may be considered comparable with that seen in human osteochondral defects after trauma.

[Painful enlargement of the 2nd toe due to an osteoid osteoma in the distal phalanx]

The rare case of an osteoid osteoma in the distal phalanx of the 2nd toe resulting in painful enlargement and hypertrophy of the entire toe in a 12-year-old girl is discussed. The tumour was excised and the oversize of the toe was corrected by exarticulation of the distal phalanx. 18 months postoperatively the patient demonstrates normal function of her forefoot without complaints or signs of inflammation.

[Osteoarthritis--histopathologic diagnosis: typing, grading, and staging]

Osteoarthritis is one of the most common diseases in modern western societies, particularly in the elderly, but it is occurring more and more often in the younger and middle-aged population, especially after traumatic injuries. The classification and grading of changes during cartilage degeneration is difficult due to the notoriously high heterogeneity of the disease process and is only partly clinically relevant. Overall, the process of joint destruction can always be evaluated for the pathogenesis (typing), its extent (staging), and the degree of the most extensive focal damage (grading). However, in the clinical routine, description and reporting of the basic findings might be best restricted to specimens obtained from endoprosthetic surgery. Only the identification of previously unknown underlying conditions such as rheumatoid disease, gout, or extensive osteonecrosis is of particular clinical interest.

DNA methylation is not responsible for p21WAF1/CIP1 down-regulation in osteoarthritic chondrocytes

OBJECTIVE

In this study, we were interested in the overall methylation level in aged and degenerated cartilage. Also, we looked at one gene which might be involved in the re-initiation of replicative activity in osteoarthritis (OA) chondrocytes, p21(WAF1/CIP1). p21(WAF1/CIP1) was previously suggested to be down-regulated in OA chondrocytes and is known to be regulated by epigenetic modulation.

METHODS

Total methylation levels were analyzed by high pressure liquid chromatography (HPLC), mRNA expression of p21(WAF1/CIP1) and DNMT enzymes by real-time polymerase chain reaction. The methylation status of the p21(WAF1/CIP1)- promotor using bisulfite genomic sequencing was evaluated.

RESULTS

General methylation analysis of genomic DNA showed no difference in between normal and aged/OA chondrocytes. Also no difference in methylation of the promotor of the p21(WAF1/CIP1) gene was detectable, which was significantly down-regulated in OA chondrocytes. DNMT1 and DNMT3a were expressed with no significant changes of expression levels found in OA chondrocytes.

CONCLUSION

Cell cycle progression inhibitor p21(WAF1/CIP1) is expressed in normal and significantly down-regulated in OA articular chondrocytes, which may mediate the re-initiation of cell proliferation in OA cartilage. However, the suppression of p21(WAF1/CIP1) mRNA expression is not due to hypermethylation of its promotor. No overall changes in genome methylation levels were found in aged or OA cartilage. Interestingly, significant expression of DNA methyltransferases was found in articular chondrocytes, which supports that DNA methylation could still be a relevant mechanism of gene regulation in (osteoarthritic) chondrocytes, though not on an overall genomic level nor specifically for the regulation of the p21(WAF1/CIP1) gene.

[Metastatic malignant choroidal melanoma: a case report about 18 years with palliative operative treatment]

Bone metastases are found in 29% of patients with metastatic malignant choroidal melanoma, which is associated with poor prognosis. However there are several reports about prolonged survival. The unusual case of a patient is described, who suffered from a melanoma with orbital invasion and survived more than 18 years. Metastases were found 12 years after initial therapy. Three palliative operations made a survival of further 7 years with high quality of life possible. Therefore moderately palliative operations are recommended in case of metastatic malignant choroidal melanoma.

Comparison of histological parameters for the diagnosis of eosinophilic oesophagitis versus gastro-oesophageal reflux disease on oesophageal biopsy material

AIMS

Eosinophil infiltration of the oesophageal epithelium is the cardinal pathomorphological finding in eosinophilic oesophagitis (EO), but gastro-oesophageal reflux disease (GORD) is also associated with increased eosinophils. The aim was to compare histological parameters for the diagnosis of EO versus GORD on routinely taken biopsy specimens.

METHODS AND RESULTS

One hundred and five routine biopsy specimens with EO (n = 62), GORD (n = 24) and probable EO (n = 19) from 74 patients (52 men, 22 women; mean age 43.7 years) were analysed for numbers of eosinophils, mast cells, degranulation and qualitative changes of oesophageal epithelium using immunohistochemistry with monoclonal antibodies against eosinophil peroxidase and eosinophil major basic protein and mast cell tryptase. Eosinophil infiltration was significantly higher in EO than in GORD both on haematoxylin and eosin staining (54.8 versus 9.1; P < 0.05) and immunohistochemistry (77.5 versus 24.7; P < 0.05). Eosinophil degranulation was significantly more intense in EO than in GORD (1.16 versus 0.41; P < 0.05). Furthermore, eosinophilia-codependent secondary qualitative changes of squamous epithelium in EO were generally more extensive than those in GORD.

CONCLUSIONS

Histological differential diagnosis of EO and GORD should be based on eosinophil counts, secondary morphological changes of eosinophils and oesophageal squamous epithelium, especially in cases suspicious of EO.

[Eosinophilic gastritis after helicobacter pylori eradication]

The development of eosinophilic gastritis immediately after Helicobacter pylori eradication has not previously been described: A 62-year-old woman developed eosinophilic gastritis immediately after a triple therapy for Helicobacter pylori eradication, consisting of pantoprazole, amoxicillin and clarithromycin. She suffered from burning epigastric pain and loss of appetite. Blood eosinophilia, gastritis and eosinophilic infiltration of the gastric corpus wall were detected. The treatment with low-dose prednisolone led to remission of the blood eosinophilia, complaints, gastritis and eosinophilic infiltration. The remission persisted after the prednisolone treatment had been finished. Eosinophilic gastritis can be diagnosed only by pathohistological examination. This need for biopsy should be stressed, because the usual gastritis treatment with proton pump inhibitors fails in cases of eosinophilic gastritis. Helicobacter pylori does not seem to play a significant role in the aetiopathology of this disorder. In our case, we suggest that the eradication drug therapy actually caused the disease.

Normalization strategies for mRNA expression data in cartilage research

OBJECTIVE

Normalization of mRNA data, i.e., the calculation of mRNA expression values comparable in between different experiments, is a major issue in biomedical and orthopaedic/rheumatology research, both for single-gene technologies [Northern blotting, conventional and quantitative polymerase chain reaction (qPCR)] and large-scale gene expression experiments. In this study, we tested several established normalization methods for their effects on gene expression measurements.

METHOD

Five standard normalization strategies were applied on a previously published data set comparing peripheral and central late stage osteoarthritic cartilage samples.

RESULTS

The different normalization procedures had profound effects on the distribution as well as the significance values of the gene expression levels. All applied normalization procedures, except the median absolute deviation scaling, showed a bias towards up- or down-regulation of genes as visualized in volcano plots. Of interest, the P-values were much more depending on the normalization procedure than the fold changes. Ten commonly used housekeeping genes showed a significant variability in between the different specimens investigated. The gene expression analysis by cDNA arrays was confirmed for these genes by qPCR.

CONCLUSION

This study documents how much normalization strategies influence the outcome of gene expression profiling analysis (i.e., the detection of regulated genes). Different normalization approaches can significantly change the P-values and fold changes of a large number of genes. Thus, it is of vital importance to check every individual step of gene expression data analysis for its appropriateness. The use of global robustness and quality measures for analyzing individual outcomes can help in estimating the reliability of final microarray study results.

[Typing, grading and staging of osteoarthritis: histopathological assessment of joint degeneration]

Osteoarthritis (degenerative arthropathy) is one of the most common diseases particular in the elderly. Osteoarthritis can principally affect all joints, although the knee, hip and phalangeal joints are most commonly involved in a clinically relevant manner. The grading and classification of changes during cartilage degeneration is complex and only partly informative for clinical management. Overall, the process of joint destruction can always be evaluated for the pathogenesis ("typing"), extent ("staging") and the degree of focal damage ("grading"). However, particularly in the final stages of the disease (e. g. in connection with prosthetic surgery) a description and report should be limited to only the most essential features, because no specific clinical relevance exists for further evaluation. Only the identification of secondary types of degenerative changes, due to as yet unknown rheumatoid diseases, gout or extensive osteonecrosis is of particular interest to clinical colleagues (i.e. typing of the joint lesion).

Localised massive tumourous xanthomatosis of the small intestine

INTRODUCTION

There are various disorders of the intestine described with accumulations of vacuolated macrophages including single or multiple xanthelasmata, Wolman's disease, cholesteryl ester storage disease (CESD), xanthomatogranulomatotic disease and xantheloma disseminatum.

CLINICAL CASE

In this paper, we report on an exceptional case of a 68-year-old male patient with a localised, massive accumulation of vacuolated, most likely lipid-loaded macrophages with an infiltrative pattern in the muscularis mucosa and propria of the small intestine leading to a tumourous mass requiring surgical removal due to impaired gut function. No enlargement of the liver or the spleen and no evidence of general abnormal lipid storage were detected elsewhere. No evidence of Wolman's or CESD was present. Also, on the ultra-structural level, the macrophages contained no cholesterol clefts typical for either Wolman's and CESD. Instead, largely empty, partly large vacuoles were seen, which most likely contained fatty acids removed during processing.

DISCUSSION

The pathogenetic mechanism of the massive local accumulation of histiocytic cells in this part of the intestine in our case remains un-clear. In summary, this case demonstrates that on rare occasions histiocytic proliferations can mimic tumourous masses with severe functional impairment of the intestine and thus should be in the differential diagnosis of gastrointestinal motility disorders.

[Histopathological examination of joint degeneration: typing, grading and staging of osteoarthritis]

Degenerative arthropathy (osteoarthritis) is one of the most common diseases in modern western societies, in particular in the elderly. The classification and grading of changes during cartilage degeneration represent complex endeavors which are only of limited value in daily pathological practice. In general, the process of joint destruction can always be evaluated for the determining pathogenesis ("typing"), extent ("staging") and degree of the most extensive focal damage ("grading"). However, for routine use one might best restrict description and reporting to the most essential features. This is in particular true for specimens obtained from endoprosthetic surgery (hips and knees), because there is currently no specific clinical relevance for further evaluation. Only the identification of secondary types of degenerative changes, such as those due to unknown rheumatoid disease, gout or extensive osteonecrosis, is of particular interest to the clinical colleague (i.e. typing of the joint lesion).

Evaluation of VEGF A expression and microvascular density as prognostic factors in extrahepatic cholangiocarcinoma

OBJECTIVES

Angiogenesis is essential for tumor growth and metastasis. An association between microvessel density, a measure of tumor angiogenesis, and conventional prognostic variables has been shown for many different tumor entities. In extrahepatic cholangiocarcinoma, the VEGF expression and microvessel density have rarely been investigated.

METHODS

Paraffin-embedded specimens from 51 resected adenocarcinomas of the extrahepatic bile duct were immunostained for vascular endothelial growth factor A (VEGF A) and CD 34 to evaluate the microvessel density (MVD). VEGF A staining was evaluated by combining intensity and percentage of positive tumor cells, as low (expression equal or below the median), or high (above the median). Microvessel density was assessed using a method published by Weidner et al.

RESULTS

Median disease free survival (DFS) of the study group was 12.5 months (range, 1-66.3 months). DFS was calculated in the 39 patients with complete resection. It was significantly better in patients with low microvessel density than DFS in patients with high microvessel density (33 months (range, 3-66.3 months) vs. 21.8 months (range, 1.6-31.6 months); p=0.022). In contrast, VEGF A expression did not correlate with survival. There was a trend toward a higher VEGF A expression in highly vascularized tumors (p=0.08), but failed to reach statistic significance.

CONCLUSIONS

The present study indicates, that vascularisation has an important impact on survival of extrahepatic cholangiocarcinoma patients. Other molecules than VEGF A are probably involved in neovascularization in extrahepatic cholangiocarcinoma.

Synergistic effect of IGF-1 and OP-1 on matrix formation by normal and OA chondrocytes cultured in alginate beads

OBJECTIVE

Growth factor therapy may be useful for stimulation of cartilage matrix synthesis and repair. Thus, the purpose of our study was to further understand the effect of combined insulin-like growth factor-1 (IGF-1) and osteogenic protein-1 (OP-1) treatment on the matrix synthesized by human adult normal and osteoarthritic (OA) chondrocytes.

DESIGN

Chondrocytes were isolated post-mortem from articular cartilage from tali of normal human donors and femoral condyles of OA patients undergoing knee replacement surgery. Cells were cultured in alginate beads for 21 days in four experimental groups: (1) "mini-ITS" control; (2) 100 ng/ml IGF-1; (3) 100 ng/ml OP-1; (4) IGF-1+OP-1, each at 100 ng/ml. Beads were processed for histological (Safranin O and fast green), morphometrical and immunohistochemical (aggrecan, decorin, type I, II, VI, and X collagens, and fibronectin accumulation) analyses.

RESULTS

Histology showed that IGF-1 alone did not induce substantial matrix production. OP-1 alone caused a considerable matrix formation, but the highest matrix accumulation by normal and OA chondrocytes was found when OP-1 and IGF-1 were added together. Morphometrical analysis indicated larger matrices produced by OA chondrocytes than by normal cells under the combined treatment. All tested matrix proteins were more abundant in the combination group. Type X collagen was detected only under the combined OP-1 and IGF-1 treatment and was present at very low levels. Type I collagen was found only in OA chondrocytes.

CONCLUSIONS

The results obtained in the current study suggest that combined therapy with IGF-1 and OP-1 may have a greater potential in treating cartilage defects seen in OA than use of either growth factor alone.

Pathobiology of osteoarthritis: pathomechanisms and potential therapeutic targets

Osteoarthritis, a degenerative joint disease, is the most disabling condition of the Western world. It affects first and foremost the articular cartilages and leads to a molecular and supramolecular destruction of the extracellular cartilage matrix. In addition, the cells, the chondrocytes, show severe alterations of their phenotype: they get anabolically and catabolically activated, change accordingly their gene expression pattern, lose their differentiated phenotype, and undergo focally cell death and cell degeneration. All these processes represent potential targets for therapeutic intervention and drug development. Apart from the cartilage itself, however, other joint tissues are also involved in the disease: thus, the synovial capsule and membrane as well as the subchondral bone account not only for most of the symptoms of the disease, but are also presumably involved in the progression of the degenerative process. Both, inflammation and stiffening within the joint capsule accelerate joint destruction. Stiffening of the subchondral bone increases the mechanical stress over the overlying cartilage during physiological movement. Altogether, there is a plethora of tissues, disease processes and targets for treating osteoarthritic joint degeneration, which will need to be followed up systematically in the future.

Artificial organs: a new option for treating osteoarthritis

Osteoarthritis is usually regarded as a localized disease whose optimal treatment is a therapy applied directly to the affected joint. Unfortunately, current local therapies such as repeated intraarticular injections or constant infusions are associated with a higher risk of infection. One way to overcome this would be to transfer substances made locally by cells within the joint. However, attempts using direct vector transfers or intraarticular injections of ex vivo modified cells could not achieve a sustained protein secretion over several months. Another method of delivering biological factors (i.e.growth hormones) intraarticularly is to transplant an artificial organ, capable of supporting the regeneration of natural cartilage, directly into the affected joint The main difficulty of having to produce bioactive factors over a long period of time is overcome by implanting a chamber-like system filled with either genetically modified cells or a drug-releasing matrix. This drug delivery system would be located at a peripheral site of the joint and could release substances directly into the joint cavity which would be transported via the synovial fluid and/or diffused to the chondrocytes or synoviocytes.

Growth Plate Cartilage as Developmental Model in Osteoarthritis Research -Potentials and Limitations

Gene expression analysis including large scale gene expression profiling has become a very basic tool for investigating the pathogenesis of degenerative joint diseases as well as for the search of new drug targets. However, gene expression analysis so far revealed very complex expression patterns rather than a clear picture of molecular changes occurring during the initiation and progression of the disease. To elucidate the molecular changes in osteoarthritis the analysis of the fetal growth plate as a developmental model for phenotypic changes in chondrocytes occurring in osteoarthritis can help in three ways: it allows to interpret gene expression patterns in the context of disease-relevant processes also occurring in developing cartilage (e.g. cell differentiation, proliferation, matrix synthesis, catabolism and calcification), it offers the chance to investigate gene function in these functional contexts by knocking out or overexpressing genes in animals, and it provides a suitable model for testing the effect of therapeutic compounds on these processes within the growing cartilage.

DNA methylation in osteoarthritic chondrocytes: a new molecular target

OBJECTIVE

To review the current knowledge of the mechanism of DNA methylation, its association with transcriptional silencing, possible mechanisms of hyper- and hypomethylation and how epigenetic changes may relate to the pathogenesis of osteoarthritis (OA).

METHODS

Journal literature was searched using Pubmed. Since there are very few publications directly on epigenetic phenomena in OA, the search was extended to give an overview of epigenetic mechanisms as they relate to the molecular mechanisms of the disease.

RESULTS

While the epigenetics of cancer cells have been intensively investigated, little attention has so far been paid as to whether epigenetic changes contribute to the pathology of non-neoplastic diseases such as OA. This review explains the mechanisms of DNA methylation, its role in transcriptional regulation, and possible demethylation mechanisms that may be applicable to OA. Preliminary evidence suggests that changes in DNA methylation, together with cytokines, growth factors and changes in matrix composition, are likely to be important in determining the complex gene expression patterns that are observed in osteoarthritic chondrocytes.

CONCLUSION

Early evidence points to a role of epigenetics in the pathogenesis of OA. Since epigenetic changes, although heritable at the cellular level, are potentially reversible, epigenetics could be a new molecular target for therapeutic intervention, especially early in the disease.

Osteoarthritis: aging of matrix and cells--going for a remedy

It has been known for a very long time that aging is the most prominent risk factor for the initiation and progression of osteoarthritis. This might be related to continuous mechanical wear and tear and/or result from time/age-related modifications of cartilage matrix components. Also a mere loss of viable cells over time, due to apoptosis or any other mechanism, might contribute. More recent evidence, however, supports that stressful conditions for the cells might promote chondrocyte senescence and might be in particular important for the progression of the osteoarthritic disease process. One of the most important implications of this hypothesis is that it points to issues of cellular degeneration as the basis for understanding of the initiation and the progression of osteoarthritis. Equally important, it emphasizes that whatever treatment we envisage for osteoarthritis, we must take into account that we are dealing with aged/(pre)senescent cells which no longer have the abilities of their juvenile counterparts to respond to the many mechanical, inflammatory, and traumatic assaults to the tissue. Thirdly, this directs treatment options to deal with the senescence of cells, which are only conceptually available today. Clearly, if accumulation of wear and tear over time is the major scenario of osteoarthritis, any therapy will largely be hopeless as moving and loading the joints is unavoidable as implication of their use. However, this review intends to open up the idea that age-related changes are less a fate, but rather a challenge for therapeutic intervention which can be taken.

Primary intraosseous meningioma of the mandible: CT and MR imaging features

We describe the rare entity of an intraosseous meningioma arising in the mandible. The meningioma was found incidentally in an asymptomatic adult patient on dental radiography, mimicking other cystic-appearing jaw masses. The CT and MR imaging features of mandibular meningioma are reviewed with reference to prior published descriptions of this unusual entity.

[Histogenesis of the skeleton and morphogenesis of cartilage-forming neoplasias]

AIMS

Fetal skeletogenesis has been extensively investigated in the vertebrates and both, cellular phenotypes and regulatory mechanisms are well characterized. This knowledge has been used in the past years to elucidate the biology of mesenchymal neoplasias of the skeleton, in particular of the cartilage forming tumors.

RESULTS

The hallmark of chondrogenic tumors is the presence of cells, which can show the full differentiation potential of physiologic chondrocytes depending on the tumor entity investigated. The phenotypic plasticity of chondrocytes explains the striking heterogeneity of cells and extracellular matrix found not only in between different, but also within chondrogenic tumor types. Hereditary exostosis is one example for which genetic analysis as well as the knowledge of regulatory pathways have contributed to our understanding of tumor development: the deficiency in functional EXT gene products explains the pathogenesis of these neoplasms.

CONCLUSIONS

In principle, chondrogenic neoplasias follow differentiation rules delineated during fetal skeletogenesis. Tumor classifications, so far based only on histomorphological criteria can be extended by molecular markers, which have the potential to contribute to a biology-orientated classification of skeletal neoplasms

[Spontaneous and post-therapeutic cartilage repair: evaluation criteria]

Articular cartilage has poor reparative capacities, and once damaged cartilage lesions remain chronic and can lead to osteoarthritis. Over the last decade, several innovative therapies have been introduced to promote the regeneration of articular cartilage while sustaining sufficient mechanical stress and permitting a pain free motion. An important measure of outcome is the morphological characterization of the repair tissue in order to allow for cross-study evaluation. The International Cartilage Repair Society has developed a analogue visual scale to quantify repair tissue, which is described in this paper.

IL-1beta and BMPs--interactive players of cartilage matrix degradation and regeneration

Intact human adult articular cartilage is central for the functioning of the articulating joints. This largely depends on the integrity of its extracellular matrix, given the high loading forces during movements in particular in the weight-bearing joints. Unlike the first impression of a more or less static tissue, articular cartilage shows - albeit in the adult organism a slow--tissue turnover. Thus, one of the most important questions in osteoarthritis research is to understand the balance of catabolic and anabolic factors in articular cartilage as this is the key to understand the biology of cartilage maintenance and degeneration. Anabolic and catabolic pathways are very much intermingled in articular cartilage. The balance between anabolism and catabolism is titrated on numerous levels, starting from the mediator-synthesizing cells which express either catabolic or anabolic factors. Also, on the level of the effector cells (i.e. chondrocytes) anabolic and catabolic gene expression compete for a balance of matrix homeostasis, namely the synthesis of matrix components and the expression and activation of matrix-degrading proteases. Also, there are multiple layers of intracellular cross-talks in between the anabolic and catabolic signalling pathways. Maybe the most important lesson from this overview is the notion that the anabolic-catabolic balance as such counts and not so much sufficient net anabolism or limited catabolism alone. Thus, it might be neither the aim of osteoarthritis therapy to foster anabolism nor to knock down catabolism, but the balance of anabolic-catabolic activities as a total might need proper titration and balancing.

IL-1β, but not BMP-7 leads to a dramatic change in the gene expression pattern of human adult articular chondrocytes—Portraying the gene expression pattern in two donors

Anabolic and catabolic cytokines and growth factors such as BMP-7 and IL-1beta play a central role in controlling the balance between degradation and repair of normal and (osteo)arthritic articular cartilage matrix. In this report, we investigated the response of articular chondrocytes to these factors IL-1beta and BMP-7 in terms of changes in gene expression levels. Large scale analysis was performed on primary human adult articular chondrocytes isolated from two human, independent donors cultured in alginate beads (non-stimulated and stimulated with IL-1beta and BMP-7 for 48 h) using Affymetrix gene chips (oligo-arrays). Biostatistical and bioinformatic evaluation of gene expression pattern was performed using the Resolver software (Rosetta). Part of the results were confirmed using real-time PCR. IL-1beta modulated significantly 909 out of 3459 genes detectable, whereas BMP-7 influenced only 36 out of 3440. BMP-7 induced mainly anabolic activation of chondrocytes including classical target genes such as collagen type II and aggrecan, while IL-1beta, both, significantly modulated the gene expression levels of numerous genes; namely, IL-1beta down-regulated the expression of anabolic genes and induced catabolic genes and mediators. Our data indicate that BMP-7 has only a limited effect on differentiated cells, whereas IL-1beta causes a dramatic change in gene expression pattern, i.e. induced or repressed much more genes. This presumably reflects the fact that BMP-7 signaling is effected via one pathway only (i.e. Smad-pathway) whereas IL-1beta is able to signal via a broad variety of intracellular signaling cascades involving the JNK, p38, NFkB and Erk pathways and even influencing BMP signaling.

B-Zell-Lymphome des Hodens

The occurrence of primary non-Hodgkin's lymphomas of the testes is described in just a few studies in the urological literature. The clinical symptomatology and especially the treatment concept for this relatively rare tumor entity are hardly discussed. Imaging diagnostics, e.g., with CT or MRI, play a decisive role in determining the diagnosis and whether a primary testicular disease is involved or a generalized systemic disease. In cases of primary B-cell lymphomas of the testes, a high inguinal orchiectomy should be performed for diagnostic and therapeutic purposes. The standard chemotherapy for aggressive non-Hodgkin's lymphomas is the CHOP regimen consisting of cyclophosphamide, doxorubicin, vincristine, and prednisone. This article presents two adults aged 67 and 75 years with histologically proven B-cell lymphoma of the testes and discusses the characteristics of this relatively rare clinical picture as well as treatment and prognosis.

Bone morphogenetic protein-7 expression and activity in the human adult normal kidney is predominantly localized to the distal nephron

Bone morphogenetic protein-7 (BMP)-7 plays an important role during fetal kidney development. In the adult, BMP-7 is most strongly expressed in the kidney compared to other organs, but the exact expression pattern as well as the function of BMP-7 is unclear. The major aim of the present study was to define which parts of the human kidney do physiologically express BMP-7 and which cells appear to be targets of BMP activity by showing phosphorylated BMP-receptor-associated Smads 1, 5, or 8 and inhibitor of differentiation factor 1 (ID1) expression. BMP-7 expression was localized by immunohistology to the epithelia of the distal tubule as well as the collecting ducts (CDs). Phospho-Smads 1/5/8 and ID1 expression largely colocalized with BMP-7 and was also localized in the epithelia of the distal tubule and the CDs. This was confirmed by polymerase chain reaction-based mRNA expression analysis. In vitro, proximal tubular cells (PTCs) expressed BMP receptors and BMP-receptor-associated Smads and were reactive to BMP-7. Our data indicate that BMP-7 expression in the adult human kidney appears to be more restricted than in the fetal situation and predominantly found in the distal nephron. Also, evidence of in vivo BMP signalling (i.e. phospho-Smads and ID1 expression) was found there. These findings suggest that BMP-7 plays a physiological role mostly in this part of the kidney. Still, as reported previously, PTCs are responsive to BMP-7, but presumably not in an autocrine or paracrine mode in normal adult kidneys.

Proposal for a histopathological consensus classification of the periprosthetic interface membrane

AIMS

The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery.

METHODS

Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria.

RESULTS

Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%).

CONCLUSION

The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.

CDRAP is expressed in adult articular cartilage, but its expression is not significantly regulated in osteoarthritic chondrocytes

OBJECTIVE

In this study we assessed the differential in vivo mRNA expression levels of CDRAP, a potential marker of cartilage degeneration.

METHODS

Conventional and real time PCR in a large series of normal (n = 18) and late stage osteoarthritic (n = 24) cartilage specimens were performed.

RESULTS

Conventional PCR analysis could demonstrate the presence of CDRAP mRNA in normal and osteoarthritic chondrocytes. Real time quantitative PCR confirmed the presence of CDRAP mRNA expression in normal articular chondrocytes in vivo (and in vitro). No significant up-regulation of CDRAP was observed in osteoarthritic chondrocytes in vivo.

CONCLUSION

The presented results confirm expression of CDRAP by normal and osteoarthritic articular chondrocytes, but indicate that increased expression levels by chondrocytes are not the cause of the increased levels of CDRAP in the synovial fluid of patients with osteoarthritis.

EXT-related pathways are not involved in the pathogenesis of dysplasia epiphysealis hemimelica and metachondromatosis

Dysplasia epiphysealis hemimelica (DEH) and metachondromatosis (MC) are considered in the differential diagnosis of solitary and hereditary osteochondromas. Both are rare disorders with DEH demonstrating cartilaginous overgrowth of an epiphysis and MC exhibiting synchronous enchondromas and osteochondromas. Ten cases of DEH and two of MC were compared with osteochondromas at the histological and molecular level. Histologically, clumping of chondrocytes within a fibrillary chondroid matrix is characteristic of DEH, while osteochondromas and MC display the characteristic growth plate architecture. Using cDNA microarray analysis we demonstrate that DEH and MC cluster separately from osteochondromas and growth plates. The EXT genes, involved in the hereditary multiple osteochondromas syndrome, and downregulated in osteochondroma, were normally expressed in DEH and MC as shown by quantitative reverse transcriptase-polymerase chain reaction (qPCR). EXT is involved in heparan sulphate biosynthesis, important for Indian Hedgehog/ParaThyroid Hormone Like Hormone (IHH/PTHLH) growth plate signalling pathways. IHH/PTHLH signalling molecules were expressed in DEH and MC as shown by both qPCR and immunohistochemistry, suggesting that this pathway is active. This is in contrast to osteochondroma, in which PTHLH signalling is downregulated. Thus, lesions of DEH and MC are separate entities from osteochondroma as confirmed by their different cDNA and protein expression profiles. Downstream targets of EXT, which are downregulated in osteochondroma, are expressed in DEH and MC, suggesting that EXT signalling is not disturbed.

Osteoarthritis: pathobiology-targets and ways for therapeutic intervention

Osteoarthritis is first and foremost the ongoing destruction of the articular cartilages of joints. Therefore, the extracellular matrix and the cells of the articular cartilages are the primary targets of osteoarthritis therapy. This tries to inhibit enzymatic destruction of the extracellular cartilage matrix as well as the modification of the cellular phenotype of the chondrocytes: cell degeneration and cell death are alongside anabolic activation and stabilization of the cellular phenotype of major interest. However, apart from the cartilage and its cells, other tissues of the joints are also important for the symptoms of the disease, which basically all originate outside the articular cartilage. In addition, changes in the subchondral bone as well as the synovial capsule and membrane are important at least for the progression of the disease process. All the named tissues offer different directions and ways for therapeutic intervention.

MMP-9/gelatinase B is a gene product of human adult articular chondrocytes and increased in osteoarthritic cartilage

OBJECTIVE

Collagen fibril degeneration involves initially the cleavage within the triple helix by the collagenases 1 (MMP-1) and 3 (MMP-13), but then mainly involves also the gelatinases A (MMP-2) and B (MMP-9). The objective of this study was to determine the quantitative expression levels as well as the distribution in normal and osteoarthritic cartilage of gelatinase B and in cultured articular chondrocytes with and without stimulation by Il-1Beta.

METHODS

Conventional and real-time quantitative PCR technology and immunohistochemistry were used to determine gelatinase B expression on the mRNA and protein level.

RESULTS

Conventional PCR analysis could demonstrate the presence of gelatinase B mRNA only in osteoarthritic chondrocytes. Real-time quantitative PCR confirmed the increased expression of gelatinase B mRNA expression in osteoarthritic chondrocytes. No significant up-regulation of gelatinase B was observed by Il-1Beta. Immunostaining for gelatinase B showed the presence of gelatinase B in a subset of normal and in a large portion of osteoarthritic chondrocytes with a more extended distribution in the latter.

CONCLUSION

In osteoarthritic cartilage destruction, gelatinase B is involved in collagen destruction though still at a very much lower level than gelatinase A. Only a very small subset of normal adult articular chondrocytes express gelatinase B in vivo suggesting that gelatinase B unlike gelatinase A is hardly or only very focally involved in physiological collagen turnover.