Prevalence and progression of arterial calcifications on computed tomography in humans with knee osteoarthritis

OBJECTIVES

Ectopic bone deposition plays an important role in osteoarthritis (OA) and in arterial wall disease. We aimed to investigate the prevalence and progression of arterial calcifications on whole-body computed tomography (CT) in persons with knee OA.

METHODS

We included 118 (36 male) participants who satisfied the clinical American College of Rheumatology classification criteria for knee OA. Baseline investigations included Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Kellgren-Lawrence grading. At baseline and after two years, a whole-body CT was performed using the same scanner and protocol. Calcifications were quantified in the carotid, brachiocephalic, coronary, thoracic aortic, abdominal aortic, iliac, femoropopliteal and crural arteries. Multivariable linear and logistic regression modeling was used for analyses.

RESULTS

At baseline males were 66.9 ± 7.7 and females were 68.0 ± 5.6 years old. Calcifications were common, all participants except two females had some calcification, and prevalence ranged between 41.8% and 94.4% for various arterial beds. Baseline femoropopliteal calcifications were associated with a higher Kellgren-Lawrence grade (more severe knee OA). Median annual progression rate was 13.1% in males and 15.7% in females. Structural OA severity was not associated with progression, but a five points lower (worse) WOMAC was associated with 1% faster progression of arterial calcifications (p= 0.008).

CONCLUSION

Around age 70 nearly all persons with knee OA have arterial calcifications, which progress substantially. For further investigation into shared causality intervention studies are needed.

Comparison of Clinical Efficacy and Mechanical Characteristics of Two Knee Distraction Devices With Relevance for Clinical Practice

OBJECTIVE

Distraction treatment for severe osteoarthritis below the age of 65 successfully postpones arthroplasty. Most patients have been treated with a general external fixator or a device specifically intended for knee distraction. This study compares clinical efficacy of both devices in retrospect and their mechanical characteristics.

DESIGN

Clinical efficacy 2 years posttreatment was compared using retrospective data from patients with severe knee osteoarthritis treated with knee distraction; 63 with the Dynamic Monotube (Stryker GmbH, Switzerland) and 65 with the KneeReviver (ArthroSave BV, the Netherlands). Changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness, and function, general well-being (SF-36), cartilage thickness by radiographic joint space widening, and adverse events during treatment were assessed. Axial stiffness of clinically feasible configurations was assessed by bench testing for the Dynamic Monotube triax system and the KneeReviver.

RESULTS

No differences were observed in clinical efficacy, nor in mechanical characteristics and adverse events between the two devices. Although with large variation, both showed a clinically relevant improvement. In mechanical testing, contact between articular surfaces was observed for both devices at physiological loading. Stiffness of applied configurations strongly varied and primarily depended on bone pin length.

CONCLUSIONS

Patients treated with a general intended-use device or a distraction-specific device both experienced clinical and structural efficacy although with significant variation between patients. The latter may be the result of varying mechanical characteristics resulting from differences in clinical configurations of the devices and actual loading. The exact role of full/partial mechanical unloading of the joint during distraction treatment remains unclear.

Increased vascular inflammation on PET/CT in psoriatic arthritis patients in comparison with controls

BACKGROUND

Patients with psoriatic arthritis (PsA) have an increased risk of cardiovascular disease, possibly due to a chronic inflammatory state.

OBJECTIVES

The main objective of this study was to investigate the difference in vascular inflammation, measured with 18-fluorodeoxyglucose positron emission tomography/CT (PET/CT), in PsA patients and controls. We conducted a secondary analysis to assess the association between clinical parameters of disease activity with vascular inflammation in PsA.

METHODS

We included a total of 75 PsA patients with active peripheral arthritis (defined as ≥2 tender and swollen joints) from an ongoing clinical trial (EudraCT 2017-003900-28) and a retrospective group of 40 controls diagnosed with melanoma, without distant metastases and not receiving immunotherapy. The main outcome measure was aortic vascular inflammation which was measured on PET/CT scans using target-to-background ratios. Clinical disease activity in PsA was assessed with joint counts, body surface area and the Disease Activity index for PsA. Laboratory assessments included C reactive protein and erythrocyte sedimentation rate.

RESULTS

Vascular inflammation was increased in patients with PsA in comparison with controls (mean target-to-background ratio for entire aorta, respectively, 1.63±0.17 vs 1.49±0.16; p=<0.001). This association remained significant after correction for gender, age, body mass index, mean arterial pressure and aortic calcification (p=0.002). Vascular inflammation was not associated with disease-related parameters.

CONCLUSIONS

Aortic vascular inflammation was significantly increased in patients with active PsA compared with controls. This evidence supports the theory that inflammation in PsA is not limited to the skin and joints but also involves the vascular system.

Identifying multivariate disease trajectories and potential phenotypes of early knee osteoarthritis in the CHECK cohort

OBJECTIVE

To gain better understanding of osteoarthritis (OA) heterogeneity and its predictors for distinguishing OA phenotypes. This could provide the opportunity to tailor prevention and treatment strategies and thus improve care.

DESIGN

Ten year follow-up data from CHECK (1002 early-OA subjects with first general practitioner visit for complaints ≤6 months before inclusion) was used. Data were collected on WOMAC (pain, function, stiffness), quantitative radiographic tibiofemoral (TF) OA characteristics, and semi-quantitative radiographic patellofemoral (PF) OA characteristics. Using functional data analysis, distinctive sets of trajectories were identified for WOMAC, TF and PF characteristics, based on model fit and clinical interpretation. The probabilities of knee membership to each trajectory were used in hierarchical cluster analyses to derive knee OA phenotypes. The number and composition of potential phenotypes was selected again based on model fit (silhouette score) and clinical interpretation.

RESULTS

Five trajectories representing different constant levels or changing WOMAC scores were identified. For TF and PF OA, eight and six trajectories respectively were identified based on (changes in) joint space narrowing, osteophytes and sclerosis. Combining the probabilities of knees belonging to these different trajectories resulted in six clusters ('phenotypes') of knees with different degrees of functional (WOMAC) and radiographic (PF) parameters; TF parameters were found not to significantly contribute to clustering. Including baseline characteristics as well resulted in eight clusters of knees, dominated by sex, menopausal status and WOMAC scores, with only limited contribution of PF features.

CONCLUSIONS

Several stable and progressive trajectories of OA symptoms and radiographic features were identified, resulting in phenotypes with relatively independent symptomatic and radiographic features. Sex and menopausal status may be especially important when phenotyping knee OA patients, while radiographic features contributed less. Possible phenotypes were identified that, after validation, could aid personalized treatments and patients selection.

Exploring the differences between radiographic joint space width and MRI cartilage thickness changes using data from the IMI-APPROACH cohort

OBJECTIVE

Longitudinal weight-bearing radiographic joint space width (JSW) and non-weight-bearing MRI-based cartilage thickness changes often show weak correlations. The current objective was to investigate these correlations, and to explore the influence of different factors that could contribute to longitudinal differences between the two methods.

METHODS

The current study included 178 participants with medial osteoarthritis (OA) out of the 297 knee OA participants enrolled in the IMI-APPROACH cohort. Changes over 2 years in medial JSW (ΔJSWmed), minimum JSW (ΔJSWmin), and medial femorotibial cartilage thickness (ΔMFTC) were assessed using linear regression, using measurements from radiographs and MRI acquired at baseline, 6 months, and 1 and 2 years. Pearson R correlations were calculated. The influence of cartilage quality (T2 mapping), meniscal extrusion (MOAKS scoring), potential pain-induced unloading (difference in knee-specific pain scores), and increased loading (BMI) on the correlations was analyzed by dividing participants in groups based on each factor separately, and comparing correlations (slope and strength) between groups using linear regression models.

RESULT

Correlations between ΔMFTC and ΔJSWmed and ΔJSWmin were statistically significant (p < 0.004) but weak (R < 0.35). Correlations were significantly different between groups based on cartilage quality and on meniscal extrusion: only patients with the lowest T2 values and with meniscal extrusion showed significant moderate correlations. Pain-induced unloading or BMI-induced loading did not influence correlations.

CONCLUSIONS

While the amount of loading does not seem to make a difference, weight-bearing radiographic JSW changes are a better reflection of non-weight-bearing MRI cartilage thickness changes in knees with higher quality cartilage and with meniscal extrusion.

Joint distraction using a purpose-built device for knee osteoarthritis: a prospective 2-year follow-up

OBJECTIVE

Knee distraction treatment for end-stage osteoarthritis successfully postpones arthroplasty for years. Studies performed thus far used general intended use, patient-personalised or custom-made devices. In this study, for the first time, a device specifically designed for knee distraction is evaluated.

DESIGN

65 patients (≤65 years) with end-stage knee osteoarthritis indicated for arthroplasty received knee distraction. Before, 1-year and 2-year post-treatment, questionnaires were filled out and knee radiographs made. Adverse events and self-reported pain medication were registered.

RESULTS

Forty-nine patients completed 2-year follow-up: one patient did not complete treatment, three patients received arthroplasty in the first and four patients in the second year follow-up. Eight patients were lost to follow-up in the second year. The total Western Ontario and McMaster Universities Osteoarthritis Index score showed a clinically relevant improvement at 1 and 2 years (+26 and +24 points), as did all subscales (all p<0.001). The minimum radiographic joint space width improved over 1 (+0.5 mm; p<0.001) and 2 (+0.4 mm; p=0.015) years, as did the physical Short-Form 36 (+10 points; p<0.001). The most common adverse event was pin tract infection, experienced by 66% of patients, in 88% successfully treated with oral antibiotics. In two cases, hospitalisation and/or intravenous antibiotics were needed. Eight patients experienced device-related complications. None of the complications influenced 2-year outcomes. Before treatment, 42% of patients used pain medication, which had nearly been halved 1 (23%; p=0.02) and 2 years (29%; p=0.27) post-treatment.

CONCLUSIONS

Patients treated with a general applicable, for knee distraction purpose-built device showed, despite adverse events, significant clinical and structural improvement over 2 years.

TRIAL REGISTRATION NUMBER

NL7986.

Relevance of Biomarkers in Serum vs. Synovial Fluid in Patients with Knee Osteoarthritis

The association between structural changes and pain sensation in osteoarthritis (OA) remains unclear. Joint deterioration in OA leads to the release of protein fragments that can either systemically (serum) or locally (synovial fluid; SF) be targeted as biomarkers and describe structural changes and potentially pain. Biomarkers of collagen type I (C1M), type II (C2M), type III (C3M), type X (C10C), and aggrecan (ARGS) degradation were measured in the serum and SF of knee OA patients. Spearman's rank correlation was used to assess the correlation of the biomarkers' levels between serum and SF. Linear regression adjusted for confounders was used to evaluate the associations between the biomarkers' levels and clinical outcomes. The serum C1M levels were negatively associated with subchondral bone density. The serum C2M levels were negatively associated with KL grade and positively associated with minimum joint space width (minJSW). The C10C levels in SF were negatively associated with minJSW and positively associated with KL grade and osteophyte area. Lastly, the serum C2M and C3M levels were negatively associated with pain outcomes. Most of the biomarkers seemed to mainly be associated with structural outcomes. The overall biomarkers of extracellular matrix (ECM) remodeling in serum and SF may provide different information and reflect different pathogenic processes.

Machine-learning predicted and actual 2-year structural progression in the IMI-APPROACH cohort

In the Innovative Medicine's Initiative Applied Public-Private Research enabling OsteoArthritis Clinical Headway (IMI-APPROACH) knee osteoarthritis (OA) study, machine learning models were trained to predict the probability of structural progression (s-score), predefined as >0.3 mm/year joint space width (JSW) decrease and used as inclusion criterion. The current objective was to evaluate predicted and observed structural progression over 2 years according to different radiographic and magnetic resonance imaging (MRI)-based structural parameters. Radiographs and MRI scans were acquired at baseline and 2-year follow-up. Radiographic (JSW, subchondral bone density, osteophytes), MRI quantitative (cartilage thickness), and MRI semiquantitative [SQ; cartilage damage, bone marrow lesions (BMLs), osteophytes] measurements were obtained. The number of progressors was calculated based on a change exceeding the smallest detectable change (SDC) for quantitative measures or a full SQ-score increase in any feature. Prediction of structural progression based on baseline s-scores and Kellgren-Lawrence (KL) grades was analyzed using logistic regression. Among 237 participants, around 1 in 6 participants was a structural progressor based on the predefined JSW-threshold. The highest progression rate was seen for radiographic bone density (39%), MRI cartilage thickness (38%), and radiographic osteophyte size (35%). Baseline s-scores could only predict JSW progression parameters (most P>0.05), while KL grades could predict progression of most MRI-based and radiographic parameters (P<0.05). In conclusion, between 1/6 and 1/3 of participants showed structural progression during 2-year follow-up. KL scores were observed to outperform the machine-learning-based s-scores as progression predictor. The large amount of data collected, and the wide range of disease stage, can be used for further development of more sensitive and successful (whole joint) prediction models. Trial Registration: Clinicaltrials.gov number NCT03883568.

Structural changes after ankle joint distraction in haemophilic arthropathy: an explorative study investigating biochemical markers and 3D joint space width

INTRODUCTION

Ankle joint distraction (AJD) is a promising treatment for patients with severe haemophilic ankle arthropathy (HAA). However, some patients showed no clinical improvement after AJD and these differences may be related to structural differences.

AIM

Primarily to quantify the structural changes after AJD in patients with HAA by the use of 3D joint space width (JSW) measurements and biochemical markers and secondarily to correlate these findings with clinical pain/function.

METHODS

Patients with haemophilia A/B who underwent AJD were included for this study. Bone contours on MRI (performed before and 12 and 36 months after AJD) were drawn manually and percentage change in JSW was calculated. Blood/urine (before and 6, 12, 24 and 36 months after AJD) was collected for biomarker measurement (COMP, CS846, C10C, CALC2, PRO-C2, CTX-II) and combined indexes of markers were calculated. Mixed effects models were used for analyses on group level. Structural changes were compared with clinical parameters.

RESULTS

Eight patients were evaluated. On group level, percentage changes in JSW showed a slight decrease after 12 months followed by a non-statistically significant increase in JSW after 36 months compared to baseline. Biochemical marker collagen/cartilage formation also showed an initial decrease, followed by a trend towards net formation 12, 24 and 36 months after AJD. On individual patient level, no clear correlations between structural changes and clinical parameters were observed.

CONCLUSION

Cartilage restoration activity on group level in patients with HAA after AJD was in concordance with clinical improvements. Correlating structural modifications with clinical parameters in the individual patient remains difficult.

Quantitative CT of the knee in the IMI-APPROACH osteoarthritis cohort: Association of bone mineral density with radiographic disease severity, meniscal coverage and meniscal extrusion

OBJECTIVE

Osteoarthritis (OA) is a highly prevalent chronic condition. The subchondral bone plays an important role in onset and progression of OA making it a potential treatment target for disease-modifying therapeutic approaches. However, little is known about changes of periarticular bone mineral density (BMD) in OA and its relation to meniscal coverage and meniscal extrusion at the knee. Thus, the aim of this study was to describe periarticular BMD in the Applied Public-Private Research enabling OsteoArthritis Clinical Headway (APPROACH) cohort at the knee and to analyze the association with structural disease severity, meniscal coverage and meniscal extrusion.

DESIGN

Quantitative CT (QCT), MRI and radiographic examinations were acquired in 275 patients with knee osteoarthritis (OA). QCT was used to assess BMD at the femur and tibia, at the cortical bone plate (Cort) and at the epiphysis at three locations: subchondral (Sub), mid-epiphysis (Mid) and adjacent to the physis (Juxta). BMD was evaluated for the medial and lateral compartment separately and for subregions covered and not covered by the meniscus. Radiographs were used to determine the femorotibial angle and were evaluated according to the Kellgren and Lawrence (KL) system. Meniscal extrusion was assessed from 0 to 3.

RESULTS

Mean BMD differed significantly between each anatomic location at both the femur and tibia (p < 0.001) in patients with KL0. Tibial regions assumed to be covered with meniscus in patients with KL0 showed lower BMD at Sub (p < 0.001), equivalent BMD at Mid (p = 0.07) and higher BMD at Juxta (p < 0.001) subregions compared to regions not covered with meniscus. Knees with KL2-4 showed lower Sub (p = 0.03), Mid (p = 0.01) and Juxta (p < 0.05) BMD at the medial femur compared to KL0/1. Meniscal extrusion grade 2 and 3 was associated with greater BMD at the tibial Cort (p < 0.001, p = 0.007). Varus malalignment is associated with significant greater BMD at the medial femur and at the medial tibia at all anatomic locations.

CONCLUSION

BMD within the epiphyses of the tibia and femur decreases with increasing distance from the articular surface. Knees with structural OA (KL2-4) exhibit greater cortical BMD values at the tibia and lower BMD at the femur at the subchondral level and levels beneath compared to KL0/1. BMD at the tibial cortical bone plate is greater in patients with meniscal extrusion grade 2/3.

Artificial Intelligence in osteoarthritis: repair by knee joint distraction shows association of pain, radiographic and immunologic outcomes

OBJECTIVES

Knee joint distraction (KJD) has been associated with clinical and structural improvement and synovial fluid (SF) marker changes. The current objective was to analyze radiographic changes after KJD using an automatic AI-based measurement method, and relate these to clinical outcome and SF markers.

METHODS

20 knee osteoarthritis patients were treated with KJD in regular care. Radiographs and WOMAC were collected before and ∼1-year post-treatment. SF was aspirated before, during, and after treatment; biomarker levels were assessed by immunoassay. Radiographs were analyzed to obtain compartmental minimum and standardized joint space width (JSW), Kellgren-Lawrence (KL) grades, compartmental joint space narrowing (JSN) scores, and osteophytosis and sclerosis scores. Results were analyzed for the most (MAC) and least affected compartment. Radiographic changes were analyzed using Wilcoxon Signed Rank tests for categorical and paired t-test for continuous variables. Linear regression was used to calculate associations between changes in JSW, WOMAC pain, and SF markers.

RESULTS

16 Patients could be evaluated. JSW, KL and JSN improved in around half of the patients, significant only for MAC JSW (p< 0.05). MAC JSW change was positively associated with WOMAC pain change (p< 0.04). Greater MCP-1 and lower TGFβ-1 increases were significantly associated with changes in MAC JSW (p< 0.05). MCP-1 changes were positively associated with WOMAC pain changes (p< 0.05).

CONCLUSION

Automatic radiographic measurements show improved joint structure in most patients after KJD in regular care. MAC JSW increased significantly and was associated with SF biomarker level changes and even with improvements in pain as experienced by these patients.

Predicted and actual 2-year structural and pain progression in the IMI-APPROACH knee osteoarthritis cohort

OBJECTIVES

The IMI-APPROACH knee osteoarthritis study used machine learning (ML) to predict structural and/or pain progression, expressed by a structural (S) and pain (P) predicted-progression score, to select patients from existing cohorts. This study evaluates the actual 2-year progression within the IMI-APPROACH, in relation to the predicted-progression scores.

METHODS

Actual structural progression was measured using minimum joint space width (minJSW). Actual pain (progression) was evaluated using the Knee injury and Osteoarthritis Outcomes Score (KOOS) pain questionnaire. Progression was presented as actual change (Δ) after 2 years, and as progression over 2 years based on a per patient fitted regression line using 0, 0.5, 1 and 2-year values. Differences in predicted-progression scores between actual progressors and non-progressors were evaluated. Receiver operating characteristic (ROC) curves were constructed and corresponding area under the curve (AUC) reported. Using Youden's index, optimal cut-offs were chosen to enable evaluation of both predicted-progression scores to identify actual progressors.

RESULTS

Actual structural progressors were initially assigned higher S predicted-progression scores compared with structural non-progressors. Likewise, actual pain progressors were assigned higher P predicted-progression scores compared with pain non-progressors. The AUC-ROC for the S predicted-progression score to identify actual structural progressors was poor (0.612 and 0.599 for Δ and regression minJSW, respectively). The AUC-ROC for the P predicted-progression score to identify actual pain progressors were good (0.817 and 0.830 for Δ and regression KOOS pain, respectively).

CONCLUSION

The S and P predicted-progression scores as provided by the ML models developed and used for the selection of IMI-APPROACH patients were to some degree able to distinguish between actual progressors and non-progressors.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT03883568.

TOFA-PREDICT study protocol: a stratification trial to determine key immunological factors predicting tofacitinib efficacy and drug-free remission in psoriatic arthritis (PsA)

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic, inflammatory, musculoskeletal disease that affects up to 30% of patients with psoriasis. Current challenges in clinical care and research include personalised treatment, understanding the divergence of therapy response and unravelling the multifactorial pathophysiology of this complex disease. Moreover, there is an urgent clinical need to predict, assess and understand the cellular and molecular pathways underlying the response to disease-modifying antirheumatic drugs (DMARDs). The TOFA-PREDICT clinical trial addresses this need. Our primary objective is to determine key immunological factors predicting tofacitinib efficacy and drug-free remission in PsA.

METHODS AND ANALYSIS

In this investigator-initiated, phase III, multicentre, open-label, four-arm randomised controlled trial, we plan to integrate clinical, molecular and imaging parameters of 160 patients with PsA. DMARD-naïve patients are randomised to methotrexate or tofacitinib. Additionally, patients who are non-responsive to conventional synthetic (cs)DMARDs continue their current csDMARD and are randomised to etanercept or tofacitinib. This results in four arms each with 40 patients. Patients are followed for 1 year. Treatment response is defined as minimal disease activity at week 16. Clinical data, biosamples and images are collected at baseline, 4 weeks and 16 weeks; at treatment failure (treatment switch) and 52 weeks. For the first 80 patients, we will use a systems medicine approach to assess multiomics biomarkers and develop a prediction model for treatment response. Subsequently, data from the second 80 patients will be used for validation.

ETHICS AND DISSEMINATION

The study was approved by the Medical Research Ethics Committee in Utrecht, Netherlands, is registered in the European Clinical Trials Database and is carried out in accordance with the Declaration of Helsinki. The study's progress is monitored by Julius Clinical, a science-driven contract research organisation.

TRIAL REGISTRATION NUMBER

EudraCT: 2017-003900-28.

Return to Sport and Work after Randomization for Knee Distraction versus High Tibial Osteotomy: Is There a Difference?

Knee joint distraction (KJD) is a novel technique for relatively young knee osteoarthritis (OA) patients. With KJD, an external distraction device creates temporary total absence of contact between cartilage surfaces, which results in pain relief and possibly limits the progression of knee OA. Recently, KJD showed similar clinical outcomes compared with high tibial osteotomy (HTO). Yet, no comparative data exist regarding return to sport (RTS) and return to work (RTW) after KJD. Therefore, our aim was to compare RTS and RTW between KJD and HTO. We performed a cross-sectional follow-up study in patients <65 years who previously participated in a randomized controlled trial comparing KJD and HTO. Out of 62 eligible patients, 55 patients responded and 51 completed the questionnaire (16 KJDs and 35 HTOs) at 5-year follow-up. The primary outcome measures were the percentages of RTS and RTW. Secondary outcome measures included time to RTS/RTW, and pre- and postoperative Tegner's (higher is more active), and Work Osteoarthritis or Joint-Replacement Questionnaire (WORQ) scores (higher is better work ability). Patients' baseline characteristics did not differ. Total 1 year after KJD, 79% returned to sport versus 80% after HTO (not significant [n.s.]). RTS <6 months was 73 and 75%, respectively (n.s.). RTW 1 year after KJD was 94 versus 97% after HTO (n.s.), and 91 versus 87% <6 months (n.s.). The median Tegner's score decreased from 5.0 to 3.5 after KJD, and from 5.0 to 3.0 after HTO (n.s.). The mean WORQ score improvement was higher after HTO (16 ± 16) than after KJD (6 ± 13; p = 0.04). Thus, no differences were found for sport and work participation between KJD and HTO in our small, though first ever, cohort. Overall, these findings may support further investigation into KJD as a possible joint-preserving option for challenging "young" knee OA patients. The level of evidence is III.

Joint distraction for osteoarthritis: clinical evidence and molecular mechanisms

Joint distraction, the prolonged mechanical separation of the bones at a joint, has emerged as a joint-preserving treatment for end-stage osteoarthritis, with the gradually growing promise of implementation in regular clinical practice. Joint distraction of the knee has been most extensively studied, with these studies showing prolonged symptomatic improvement in combination with repair of cartilage tissue in degenerated knee joints, supporting the concept that cartilage repair can translate into real clinical benefit. The reversal of tissue degeneration observed with joint distraction could be the result of one or a combination of various proposed mechanisms, including partial unloading, synovial fluid pressure oscillation, mechanical and biochemical changes in subchondral bone, adhesion and chondrogenic commitment of joint-derived mesenchymal stem cells or a change in the molecular milieu of the joint. The overall picture that emerges from the combined evidence is relevant for future research and treatment-related improvements of joint distraction and for translation of the insights gained about tissue repair to other joint-preserving techniques. It remains to be elucidated whether optimizing the biomechanical conditions during joint distraction can actually cure osteoarthritis rather than only providing temporary symptomatic relief, but even temporary relief might be relevant for society and patients, as it will delay joint replacement with a prosthesis at an early age and thereby avert revision surgery later in life. Most importantly, improved insights into the underlying mechanisms of joint repair might provide new leads for more targeted treatment options.

Neuropathic pain in the IMI-APPROACH knee osteoarthritis cohort: prevalence and phenotyping

Objectives

Osteoarthritis (OA) patients with a neuropathic pain (NP) component may represent a specific phenotype. This study compares joint damage, pain and functional disability between knee OA patients with a likely NP component, and those without a likely NP component.

Methods

Baseline data from the Innovative Medicines Initiative Applied Public-Private Research enabling OsteoArthritis Clinical Headway knee OA cohort study were used. Patients with a painDETECT score ≥19 (with likely NP component, n=24) were matched on a 1:2 ratio to patients with a painDETECT score ≤12 (without likely NP component), and similar knee and general pain (Knee Injury and Osteoarthritis Outcome Score pain and Short Form 36 pain). Pain, physical function and radiographic joint damage of multiple joints were determined and compared between OA patients with and without a likely NP component.

Results

OA patients with painDETECT scores ≥19 had statistically significant less radiographic joint damage (p≤0.04 for Knee Images Digital Analysis parameters and Kellgren and Lawrence grade), but an impaired physical function (p<0.003 for all tests) compared with patients with a painDETECT score ≤12. In addition, more severe pain was found in joints other than the index knee (p≤0.001 for hips and hands), while joint damage throughout the body was not different.

Conclusions

OA patients with a likely NP component, as determined with the painDETECT questionnaire, may represent a specific OA phenotype, where local and overall joint damage is not the main cause of pain and disability. Patients with this NP component will likely not benefit from general pain medication and/or disease-modifying OA drug (DMOAD) therapy. Reserved inclusion of these patients in DMOAD trials is advised in the quest for successful OA treatments.

Trial registration number

The study is registered under clinicaltrials.gov nr: NCT03883568.

Knee Joint Distraction as Treatment for Osteoarthritis Results in Clinical and Structural Benefit: A Systematic Review and Meta-Analysis of the Limited Number of Studies and Patients Available

OBJECTIVE

Knee joint distraction (KJD) is a joint-preserving osteoarthritis treatment that may postpone a total knee arthroplasty (TKA) in younger patients. This systematic review and meta-analysis evaluates short- and long-term clinical benefit and tissue structure changes after KJD.

DESIGN

MEDLINE, EMBASE, and Web of Science were searched for eligible clinical studies evaluating at least one of the primary parameters: WOMAC, VAS-pain, KOOS, EQ5D, radiographic joint space width or MRI cartilage thickness after KJD. Random effects models were applied on all outcome parameters and outcomes were compared with control groups found in the included studies.

RESULTS

Eleven articles reporting on 7 different KJD cohorts with in total 127 patients and 5 control groups with multiple follow-up moments were included, of which 2 were randomized controlled trials. Significant improvements in all primary parameters were found and benefit lasted up to at least 9 years. Overall, outcomes were comparable with control groups, including high tibial osteotomy, although TKA showed better clinical response.

CONCLUSIONS

Current, still limited, evidence shows KJD causes clear benefit in clinical and structural parameters, both short- and long-term. Longer follow-up with more patients is necessary, to validate outcome and to potentially improve patient selection for this intensive treatment. Thus far, for younger knee osteoarthritis patients, KJD may be an option to consider.

Performance of knee image digital analysis of radiographs of patients with end-stage knee osteoarthritis

OBJECTIVE

Knee Image Digital Analysis (KIDA) is standardized radiographic analysis software for measuring osteoarthritis (OA) characteristics. It was validated in mild OA, but used for severe OA as well. The current goal was to evaluate the performance of KIDA in severe OA.

DESIGN

Of 103 patients, standardized radiographs were performed before and one and 2 years after treatment for severe OA. All radiographs were evaluated on subchondral bone density, joint space width (JSW), osteophytes, eminence height, and joint angle, twice within years by the same observer. Part of the radiographs were randomly selected for reevaluation twice within 1 month and evaluation by another observer. The intraclass correlation coefficient (ICC), smallest detectable difference (SDD) and coefficient of variation (CV) were calculated; the SDD and CV were compared to those in mild OA. The relation of severity with KIDA parameters and with observer differences was calculated with linear regression.

RESULTS

Intra-observer ICCs were higher in the 98 severe radiographs reanalyzed within 1 month (all >0.8) than the 293 reanalyzed within years (all >0.5; most >0.8) and than inter-observer ICCs (all >0.7). SDDs and CVs were smaller when reanalyzed within a month and comparable to those in mild OA. Some parameters showed bias between readings. Severity showed significant relation with osteophytes and JSW parameters, and with the observer variation in these parameters (all P < 0.04).

CONCLUSIONS

KIDA is a well-performing tool also for severe OA. In order to decrease variability and SDDs, images should be analyzed in a limited time frame and randomized order.

Comparison between 2D radiographic weight-bearing joint space width and 3D MRI non-weight-bearing cartilage thickness measures in the knee using non-weight-bearing 2D and 3D CT as an intermediary

Background:

In knee osteoarthritis, radiographic joint space width (JSW) is frequently used as a surrogate marker for cartilage thickness; however, longitudinal changes in radiographic JSW have shown poor correlations with those of magnetic resonance imaging (MRI) cartilage thickness. There are fundamental differences between the techniques: radiographic JSW represents two-dimensional (2D), weight-bearing, bone-to-bone distance, while on MRI three-dimensional (3D) non-weight-bearing cartilage thickness is measured. In this exploratory study, computed tomography (CT) was included as a third technique, as it can measure bone-to-bone under non-weight-bearing conditions. The objective was to use CT to compare the impact of weight-bearing versus non-weight-bearing, as well as bone-to-bone JSW versus actual cartilage thickness, in the knee.

Methods:

Osteoarthritis patients (n = 20) who were treated with knee joint distraction were included. Weight-bearing radiographs, non-weight-bearing MRIs and CTs were acquired before and 2 years after treatment. The mean radiographic JSW and cartilage thickness of the most affected compartment were measured. From CT, the 3D median JSW was calculated and a 2D projectional image was rendered, positioned similarly and measured identically to the radiograph. Pearson correlations between the techniques were derived, both cross-sectionally and longitudinally.

Results:

Fourteen patients could be analyzed. Cross-sectionally, all comparisons showed moderate to strong significant correlations (R = 0.43–0.81; all p < 0.05). Longitudinal changes over time were small; only the correlations between 2D CT and 3D CT (R = 0.65; p = 0.01) and 3D CT and MRI (R = 0.62; p = 0.02) were statistically significant.

Conclusion:

The poor correlation between changes in radiographic JSW and MRI cartilage thickness appears primarily to result from the difference in weight-bearing, and less so from measuring bone-to-bone distance versus cartilage thickness.

Knee joint distraction results in MRI cartilage thickness increase up to ten years after treatment

Objectives

Knee joint distraction (KJD) has been shown to result in long-term clinical improvement and short-term cartilage restoration in young OA patients. The objective of the current study was to evaluate MRI cartilage thickness up to 10 years after KJD treatment, using a 3D surface-based approach.

Methods

Twenty end-stage knee OA patients were treated with KJD. MRI scans (1.5 T) were performed before and at 1, 2, 5, 7, and 10 years after treatment. Tibia and femur cartilage segmentation and registration to a canonical surface were performed semi-automatically. Statistical parametric mapping with linear mixed models was used to analyse whole-joint changes. The influence of baseline patient characteristics was analysed with statistical parametric mapping using linear regression. Relevant weight-bearing parts of the femur were selected to obtain the average cartilage thickness in the femur and tibia of the most- (MAC) and least-affected compartment. These compartmental changes over time were analysed using repeated measures ANOVA; missing data was imputed. In all cases, P <0.05 was considered statistically significant.

Results

One and 2 years post-treatment, cartilage in the MAC weight-bearing region was significantly thicker than pre-treatment, gradually thinning after 5 years, but still increased at 10 years post-treatment. Long-term results showed that areas in the least-affected compartment were significantly thicker than pre-treatment. Male sex and more severe OA at baseline somewhat predicted shorter-term benefit (P >0.05). Compartmental analyses showed significant short- and long-term thickness increase in the tibia and femur MAC (all P <0.05).

Conclusion

KJD results in significant short- and long-term cartilage regeneration, up to 10 years post-treatment.

Trial registration

Netherlands Trial Register, https://www.trialregister.nl, NL419.

Knee Joint Distraction Compared with High Tibial Osteotomy and Total Knee Arthroplasty: Two-Year Clinical, Radiographic, and Biochemical Marker Outcomes of Two Randomized Controlled Trials

OBJECTIVE

Both, knee joint distraction (KJD) and high tibial osteotomy (HTO) are joint-preserving surgeries that postpone total knee arthroplasty (TKA) in younger osteoarthritis (OA) patients. Here we evaluate the 2-year follow-up of KJD versus TKA and KJD versus HTO in 2 noninferiority studies.

DESIGN

Knee OA patients indicated for TKA were randomized to KJD (n = 20; KJD_TKA) or TKA (n = 40). Medial compartmental knee OA patients considered for HTO were randomized to KJD (n = 23; KJD_HTO) or HTO (n = 46). Patient-reported outcome measures were assessed over 2 years of follow-up. The radiographic joint space width (JSW) was measured yearly. In the KJD groups, serum-PIIANP and urinary-CTXII levels were measured as collagen type-II synthesis and breakdown markers. It was hypothesized that there was no clinically important difference in the primary outcome, the total WOMAC, when comparing KJD with HTO and with TKA.

RESULTS

Both trials were completed, with 114 patients (19 KJD_TKA; 34 TKA; 20 KJD_HTO; 41 HTO) available for 2-year analyses. At 2 years, the total WOMAC score (KJDTKA: +30.4 [95% CI 23.0-37.9] points; TKA: +42.4 [95% CI 38.1-46.8]; KJDHTO: +21.6 [95% CI 13.8-29.4]; HTO: +29.2 [95% CI 23.6-34.8]; all: P < 0.05) and radiographic minimum JSW (KJDTKA: +0.9 [95% CI 0.2-1.6] mm; KJDHTO: +0.9 [95% CI 0.5-1.4]; HTO: +0.6 [95% CI 0.3-0.9]; all: P < 0.05) were still increased for all groups. The net collagen type-II synthesis 2 years after KJD was increased (P < 0.05). Half of KJD patients experienced pin tract infections, successfully treated with oral antibiotics.

CONCLUSIONS

Sustained improvement of clinical benefit and (hyaline) cartilage thickness increase after KJD is demonstrated. KJD was clinically noninferior to HTO and TKA in the primary outcome.

Reduction of pin tract infections during external fixation using cadexomer iodine

PURPOSE

Knee joint distraction (KJD) is a joint-preserving treatment for younger osteoarthritis patients. KJD has shown positive results in regular care, but the external fixation frame often caused pin tract skin infections. Therefore, the use of cadexomer iodine was included in the wound care protocol. The goal of this cross-sectional study was to evaluate whether use of this ointment reduced the number of patients with infections during KJD treatment.

METHODS

Patients treated with KJD in regular care were included if they gave consent for use of their data and completed treatment with the newest distraction device before 2020. All patients followed a wound care protocol, which since March 2019 included using cadexomer iodine ointment. The number of patients experiencing pin tract infections was compared between patients who did (March 2019-December 2019) and did not (November 2017-March 2019) use the ointment.

RESULTS

Sixty-seven patients were included; 34 patients used cadexomer iodine and 33 patients did not. Patient who did not use cadexomer iodine experienced twice as many infections (64% vs 32%;p = 0.010). There was a significant difference in the number of patients with serious infections, requiring more antibiotics than the standard 7-day oral antibiotics (30% without vs 6% with cadexomer iodine; p = 0.009).

CONCLUSIONS

The use of cadexomer iodine ointment during KJD results in a significant reduction of the number of patients experiencing pin tract infections during treatment. Use of this ointment should be considered standard protocol during KJD treatment and could be of value in general external fixator usage as well.

Cohort profile: The Applied Public-Private Research enabling OsteoArthritis Clinical Headway (IMI-APPROACH) study: a 2-year, European, cohort study to describe, validate and predict phenotypes of osteoarthritis using clinical, imaging and biochemical markers

PURPOSE

The Applied Public-Private Research enabling OsteoArthritis Clinical Headway (APPROACH) consortium intends to prospectively describe in detail, preselected patients with knee osteoarthritis (OA), using conventional and novel clinical, imaging, and biochemical markers, to support OA drug development.

PARTICIPANTS

APPROACH is a prospective cohort study including 297 patients with tibiofemoral OA, according to the American College of Rheumatology classification criteria. Patients were (pre)selected from existing cohorts using machine learning models, developed on data from the CHECK cohort, to display a high likelihood of radiographic joint space width (JSW) loss and/or knee pain progression.

FINDINGS TO DATE

Selection appeared logistically feasible and baseline characteristics of the cohort demonstrated an OA population with more severe disease: age 66.5 (SD 7.1) vs 68.1 (7.7) years, min-JSW 2.5 (1.3) vs 2.1 (1.0) mm and Knee injury and Osteoarthritis Outcome Score pain 31.3 (19.7) vs 17.7 (14.6), except for age, all: p<0.001, for selected versus excluded patients, respectively. Based on the selection model, this cohort has a predicted higher chance of progression.

FUTURE PLANS

Patients will visit the hospital again at 6, 12 and 24 months for physical examination, pain and general health questionnaires, collection of blood and urine, MRI scans, radiographs of knees and hands, CT scan of the knee, low radiation whole-body CT, HandScan, motion analysis and performance-based tests.After two years, data will show whether those patients with the highest probabilities for progression experienced disease progression as compared to those wit lower probabilities (model validation) and whether phenotypes/endotypes can be identified and predicted to facilitate targeted drug therapy.

TRIAL REGISTRATION NUMBER

NCT03883568.

The molecular profile of synovial fluid changes upon joint distraction and is associated with clinical response in knee osteoarthritis

OBJECTIVE

Surgical knee joint distraction (KJD) leads to clinical improvement in knee osteoarthritis (OA) and also apparent cartilage regeneration by magnetic resonance imaging. We investigated if alteration of the joint's mechanical environment during the 6 week period of KJD was associated with a molecular response in synovial fluid, and if any change was associated with clinical response.

METHOD

20 individuals undergoing KJD for symptomatic radiographic knee OA had SF sampled at baseline, midpoint and endpoint of distraction (6 weeks). SF supernatants were measured by immunoassay for 10 predefined mechanosensitive molecules identified in our previous pre-clinical studies. The composite Knee injury and OA Outcome Score-4 (KOOS₄) was collected at baseline, 3, 6 and 12 months.

RESULTS

13/20 (65%) were male with mean age 54°±°5yrs. All had Kellgren-Lawrence grade ≥2 knee OA. 6/10 analytes showed statistically significant change in SF over the 6 weeks distraction (activin A; TGFβ-1; MCP-1; IL-6; FGF-2; LTBP2), P < 0.05. Of these, all but activin A increased. Those achieving the minimum clinically important difference of 10 points for KOOS₄ over 6 months showed greater increases in FGF-2 and TGFβ-1 than non-responders. An increase in IL-8 during the 6 weeks of KJD was associated with significantly greater improvement in KOOS₄ over 12 months.

CONCLUSION

Detectable, significant molecular changes are observed in SF following KJD, that are remarkably consistent between individuals. Preliminary findings appear to suggest that increases in some molecules are associated with clinically meaningful responses. Joint distraction may provide a potential opportunity in the future to define regenerative biomarker(s) and identify pathways that drive intrinsic cartilage repair.

Knee joint distraction in regular care for treatment of knee osteoarthritis: A comparison with clinical trial data

Objectives

Knee joint distraction (KJD) has been evaluated as a joint-preserving treatment to postpone total knee arthroplasty in knee osteoarthritis patients in three clinical trials. Since 2014 the treatment is used in regular care in some hospitals, which might lead to a deviation from the original indication and decreased treatment outcome. In this study, baseline characteristics, complications and clinical benefit are compared between patients treated in regular care and in clinical trials.

Methods

In our hospital, 84 patients were treated in regular care for 6 weeks with KJD. Surgical details, complications, and range of motion were assessed from patient hospital charts. Patient-reported outcome measures were evaluated in regular care before and one year after treatment. Trial patients (n = 62) were treated and followed as described in literature.

Results

Patient characteristics were not significantly different between groups, except for distraction duration (regular care 45.3±4.3; clinical trials 48.1±8.1 days; p = 0.019). Pin tract infections were the most occurring complication (70% regular care; 66% clinical trials), but there was no significant difference in treatment complications between groups (p>0.1). The range of motion was recovered within a year after treatment for both groups. WOMAC questionnaires showed statistically and clinically significant improvement for both groups (both p<0.001 and >15 points in all subscales) and no significant differences between groups (all differences p>0.05). After one year, 70% of patients were responders (regular care 61%, trial 75%; p = 0.120). Neither regular care compared to clinical trial, nor any other characteristic could predict clinical response.

Conclusions

KJD as joint-preserving treatment in clinical practice, to postpone arthroplasty for end-stage knee osteoarthritis patient below the age of 65, results in an outcome similar to that thus far demonstrated in clinical trials. Longer follow-up in regular care is needed to test whether also long-term results remain beneficial and comparable to trial data.

Initial tissue repair predicts long-term clinical success of knee joint distraction as treatment for knee osteoarthritis

OBJECTIVE

Knee joint distraction (KJD), a joint-preserving surgery for severe osteoarthritis (OA), provides clinical and structural improvement and postpones the need for total knee arthroplasty (TKA). This study evaluates 9-year treatment outcome and identifies characteristics predicting long-term treatment success.

DESIGN

Patients with severe tibiofemoral OA (n = 20; age<60 years) indicated for TKA were treated with KJD. Questionnaires, radiographs, and magnetic resonance imaging (MRI) were used for evaluation. Survival after treatment was analyzed, where 'failure' was defined by TKA over time.

RESULTS

9-year survival was 48%, and 72% for men (compared to 14% for women; P = 0.035) and 73% for those with a first-year minimum joint space width (JSW) increase of >0.5 mm (compared to 0% for <0.05 mm; P = 0.002). Survivors still reported clinical improvement compared to baseline (ΔWOMAC +29.9 points (95%CI 16.9-42.9; P = 0.001), ΔVAS -46.8 mm (-31.6-61.9; P < 0.001)). Surprisingly, patients getting TKA years after KJD still reported clinical improvement although less pronounced (ΔWOMAC +20.5 points (-1.8-42.8; P = 0.067), ΔVAS -25.4 mm (-3.2-47.7; P = 0.030)). Survivors showed long-lasting minimum JSW increase (baseline 0.3 mm (IQR 1.9), follow-up 1.3 mm (2.5); P = 0.017) while 'failures' did not (baseline 0.4 mm (1.8), follow-up 0.2 mm (1.5); P = 0.161). First-year minimum JSW on radiographs and cartilage thickness increase on MRI predict 9-year survival (HR 0.05 and 0.12, respectively; both P < 0.026). Male gender was associated with survival (HR 0.24; P = 0.050).

CONCLUSIONS

KJD shows long-lasting clinical and structural improvement. In addition to a greater survival rate for males (>two out of three), the initial cartilage repair activity appears to be important for long-term clinical success.

Progressive realisation of universal health coverage: what are the required processes and evidence?

Progressive realisation is invoked as the guiding principle for countries on their own path to universal health coverage (UHC). It refers to the governmental obligations to immediately and progressively move towards the full realisation of UHC. This paper provides procedural guidance for countries, that is, how they can best organise their processes and evidence collection to make decisions on what services to provide first under progressive realisation. We thereby use 'evidence-informed deliberative processes', a generic value assessment framework to guide decision making on the choice of health services. We apply this to the concept of progressive realisation of UHC. We reason that countries face two important choices to achieve UHC. First, they need to define which services they consider as high priority, on the basis of their social values, including cost-effectiveness, priority to the worse off and financial risk protection. Second, they need to make tough choices whether they should first include more priority services, first expand coverage of existing priority services or first reduce co-payments of existing priority services. Evidence informed deliberative processes can facilitate these choices for UHC, and are also essential to the progressive realisation of the right to health. The framework informs health authorities on how they can best organise their processes in terms of composition of an appraisal committee including stakeholders, of decision-making criteria, collection of evidence and development of recommendations, including their communication. In conclusion, this paper fills in an important gap in the literature by providing procedural guidance for countries to progressively realise UHC.

[Sleep-wake patterns in adults with autism spectrum disorders in a clinical setting: a pilot study]

The negative consequences of sleep-wake disorders in the general population and in children with an autism spectrum disorder (ASD) are well-established. However, little is known about sleep-wake disorders in adults with ASD.<br/> AIM: To study and measure sleep-wake disorders and sleep-wake patterns in adults in a clinical facility who have been diagnosed primarily as having ASD without any comorbid intellectual disability.<br/> METHOD: We assessed the sleep patterns of 19 patients in a residential facility. We asked patients to provide their sleep history, answer questionnaires and keep a sleep diary (subjective measurement). We also asked patients to collect actigraphy data (objective measurement) for seven days and to provide information about comorbid symptoms of anxiety and depression and use of medication.<br/> RESULTS: Nine patients (47%) had undiagnosed comorbid sleep-wake disorders. Patients in our study overrated their sleep efficiency (diary) compared to objective data (actigraphy). However, patients' subjective sleep quality did match patients' sleep efficiency. Only two out of 14 patients with symptoms of anxiety and/or depression were diagnosed with a comorbid depressive disorder, 15 patients were treated with medication.<br/> CONCLUSION: Sleep-wake disorders and comorbid symptoms of anxiety and depression might be more prevalent in adults with ASD in a residential facility than reported so far. This possibility needs to be considered more carefully during the diagnostic process and during treatment.

The PropeR way to support medical doctors in daily practice. Developing the protocol based DSS

This paper describes the first phase of the development of a Protocol based Decision Support System (PDSS) that will be linked to an Electronic Patient Record system (EPR system). The protocol system will be pro-active: the physician will be automatically prompted from the EPR of a particular patient if the protocol that applies for that patient defines it necessary. The PropeR project studies the impact of a PDSS that is linked to an EPR on daily care processes. There are two areas of research: hospital and home care. This paper describes the application in the hospital. The protocol that is being computerized is a treatment protocol for Acute Myelogenous Leukaemia (AML) that also studies treatment alternatives (conventional versus experimental treatment). This paper based AML protocol has been translated into a formal representation. The KA-tool Gaston is used to make this representation. Twenty-eight subprotocols have been organized in a hierarchical structure with three levels. One of the aims of the project is to make a representation of the AML protocol that can be used in other organizations as well. The main problem we encountered is that the representation not only contains the content of the protocol, but also aspects of application of that protocol in daily care of the hospital and aspects of support. The solution to this problem is the creation of two layers of representation: the first layer is an exact copy of the protocol and thus sharable and the second layer focuses on the support of the protocol in the daily working processes and is mainly domain specific: for the University Hospital Maastricht. At the moment, this division into two layers is being discussed.

Morphologically normal, CD30-negative B-lymphocytes with chromosome aberrations in classical Hodgkin's disease: the progenitor cell of the malignant clone?

A recent study observed that numerical chromosome abnormalities in Hodgkin's disease (HD) are detected not only in morphologically abnormal Hodgkin/Reed-Sternberg cells, but also in a fraction of morphologically normal cells. However, the phenotypic constitution of these genetically abnormal, morphologically normal cells and their relationship to the malignant Hodgkin/Reed-Sternberg cells could not be established in the earlier cases studied, because of the low frequency of these cells. The present study investigated two cases of classical Hodgkin's disease containing a relatively large population of such apparently normal cells with aberrant chromosome copy numbers. The phenotype and their position within the developmental route of the malignant compartment were examined by a combined in situ hybridization and immunocytochemistry approach. Numerical abnormalities for chromosome 1 in one case and for chromosomes X, Y, and 1 in the other case were observed not only in CD30-positive Hodgkin/Reed-Sternberg cells, but also in CD30-negative, morphologically normal cells. It was shown that these genetically aberrant cells expressed the B-cell antigen CD19, thus confirming their B-cell nature. These studies indicate a relationship between the genome aberrations in these genetically abnormal, morphologically normal B-cells and the Hodgkin/Reed-Sternberg cells, suggesting that they are progenitor cells of the malignant cell fraction.

Chromosomal abnormalities in Hodgkin's disease are not restricted to Hodgkin/Reed-Sternberg cells

Hodgkin and Reed-Sternberg cells are considered to represent the malignant fraction in Hodgkin's disease. Several studies have shown that the Hodgkin and Reed-Sternberg cells are chromosomally abnormal, but genetic data about the morphologically normal cell population in Hodgkin's disease are very limited. This latter cell population has therefore been examined for chromosomal aberrations, using the in situ hybridization (ISH) procedure, making use of DNA probes for chromosomes 1, 7, 8, 9, 11, 12, 15, 17, and 18. Nuclei were isolated from freshly frozen (10 cases) and paraffin-embedded (16 cases) biopsy samples and 1000 nuclei per case were evaluated. The cases of Hodgkin's disease were compared with reactive lymph nodes, which show aberrant chromosome copy numbers in less than 1 per cent of the cells. Using strict scoring criteria, nuclei in the tumour were found to show an abnormal genotype, in the range of 1-12 per cent, with trisomies occurring most frequently. No characteristic numerical chromosome abnormality was observed. ISH on 4 microns thick paraffin sections of six cases of Hodgkin's disease revealed numerical aberrations for chromosome 1 in cells which appeared to be morphologically normal. The genomically abnormal nuclei did not differ in morphology or size from the nuclei of morphologically normal cells, but differed considerably in size when compared with the nuclei of Hodgkin/Reed-Sternberg cells after the ISH procedure. Three of these six cases revealed a population of apparently normal cells with an aberrant copy number which differed notably from the fraction observed in reactive lymph nodes. It is concluded, therefore, that a subset of morphologically normal cells, next to the Hodgkin/Reed-Sternberg cells, are chromosomally aberrant and may participate in the malignant cell fraction of Hodgkin's disease.

Comparison of A and B-type lamin expression in reactive lymph nodes and nodular sclerosing Hodgkin's disease

AIMS

In order to clarify the differentiation and proliferation status of the Reed-Sternberg and Hodgkin cells we studied A and B-type lamin expression with specific monoclonal antibodies in nodular sclerosing Hodgkin's disease. Its normal counterpart, the reactive lymph node, was also examined for lamin subtype expression.

METHODS AND RESULTS

The CD20 positive centrocytes and centroblasts of the follicle centre in the reactive lymph nodes expressed lamin B1, but were not or only very weakly positive for lamin B2 or A-type lamin antibodies. Mantle zone lymphocytes displayed lamins B1 and B2, but were negative for A-type lamins. Furthermore, CD3- and CD20-positive lymphocytes in the medulla and paracortex lacked A-type lamins, but were positive for both B-type lamins. Finally, the proliferation marker Ki67 was mainly detected in the centroblasts, but also in a fraction of the A-type lamin negative cells in the paracortex and medulla. In Hodgkin's disease, all cells expressed lamins B1 and B2, whereas A-type lamins were primarily observed in CD30-positive Reed-Sternberg and Hodgkin cells. About 20% of the Reed-Sternberg and Hodgkin cells expressed Ki67, with co-expression of lamin A in most of these cells.

CONCLUSIONS

Ki67 and A-type lamin staining were in general mutually exclusive in lymph nodes, indicating that A-type lamin positive cells are not proliferative. This suggests also that the A-type lamin expression in Reed-Sternberg and Hodgkin cells is correlated with a relatively mature phenotype of these malignant cells. However, some of these differentiated malignant cells still have a capacity to proliferate as indicated by Ki67 positivity. Our observation that lamin B2 expression in the follicle centre cells of the reactive lymph node is low or absent indicates that this lamin subtype is not always expressed in nucleated cells, which is in clear contrast to the results obtained in previous studies in other diseases and in normal tissues. Absence of lamin B2 expression may be associated with the follicle centre stage of B-cells.

A novel triple-color detection procedure for brightfield microscopy, combining in situ hybridization with immunocytochemistry

We describe a fast light microscopic procedure for the simultaneous enzyme cytochemical detection of three different DNA target sequences in contrasting colors in both interphase and metaphase cell preparations. Chromosome-specific DNA probes labeled with either biotin, digoxygenin, or fluorescein were hybridized as a mixture and detected clearly and accurately by precipitates of the horseradish peroxidase-diaminobenzidine (PO-DAB, brown color), alkaline phosphatase-Fast Red (APase-Fast Red, red color), or horseradish peroxidase-tetramethylbenzidine (PO-TMB, green color) reaction, respectively. The PO-TMB reaction product was stabilized effectively by the addition of sodium tungstate to the reaction mixture, thus making the PO-TMB reaction now generally applicable to in situ hybridization (ISH). To avoid mixing of the precipitates of the two PO reactions used in the triple-color ISH method, the first detected PO activity was always completely inactivated by a mild acid treatment before the second one was applied. Finally, the cell preparations were embedded in a thin protein layer cross-linked by formaldehyde to ensure permanent stabilization of the enzyme reaction products and optimal visualization of color contrast. The triple-color ISH detection procedure could be combined with beta-galactosidase-5-bromo-4-chloro-3-indolyl-beta- D-galactoside (beta-Gal-BCIG) immunocytochemistry (ICC), leading to the simultaneous localization of multiple DNA targets and a protein target in the same cell. The described procedure may therefore be a valuable tool in the areas of cytogenetics, cell biology, and molecular pathology.