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Biomarkers of Joint Destruction and Repair

 

Objectives

·        Identify new and promising biomarkers for diseases characterized by progressive joint destruction

·         Define the knowledge gaps and research opportunities to advance the understanding and use of biomarkers as surrogate endpoints in clinical trials for diseases characterized by progressive joint destruction

 

Agenda

Moderator:    Kenneth D. Brandt, M.D., Indiana University School of Medicine

Introductory Remarks:           Suzanne Serrate-Sztein, M.D., National Institute of Arthritis and Musculoskeletal and Skin Diseases

 

Session I.  Imaging Technologies

Imaging Markers of Joint Destruction and Repair

Charles G. Peterfy, M.D., Ph.D., University of California, San Francisco, and Synarc, Inc.

Imaging Biomarkers in Back Pain

Robert D. Boutin, M.D., University of California and Veterans Affairs Medical Center, San Diego

Imaging Biomarkers in Osteoarthritis

Harry Genant, M.D., University of California, San Francisco

Imaging Technology for Osteoarthritis

Mark E. Brezinski, M.D., Ph.D., Massachusetts General Hospital

 

Discussion

Session II.  Inflammatory and Genetic Markers

Cytokine Expression in Arthritis

Gary S. Firestein, M.D., University of California, San Diego

Genetic and Major Histocompatibility Complex Markers of Disease Severity in Rheumatoid Arthritis

Cornelia M. Weyand, M.D., Ph.D., Mayo Foundation

 

Discussion

Session III.  Biochemical Markers of Cartilage Breakdown and Repair

Serum Markers of Joint Metabolism

Eugene J-M.A. Thonar, Ph.D., Rush Medical College

Molecular Markers in Osteoarthritis

Stefan L. Lohmander, M.D., Ph.D., University of Lund, Sweden

 

Biomarkers of Joint Destruction and Repair (continued)

Collagen Type II Cross-Linked Telopeptides:  A Promising Marker of Cartilage Degradation       in Arthritis

David Eyre, Ph.D., University of Washington

Synovial Fluid Markers of Osteoarthritis

Kenneth D. Brandt, M.D.

Discussion

Summary and Conclusions

 

Imaging Markers of Joint Destruction and Repair

Charles G. Peterfy, M.D., Ph.D. and Harry K. Genant, M.D.  

The past two decades have seen remarkable advances in medical imaging.  The development of magnetic resonance imaging, in particular, has brought unprecedented power to the study of joint disease and its causes and has offered a unique opportunity to explore arthritis in ways not imaginable in the past.  This discussion will review the different roles that medical imaging can play in clinical trials and outline the deliverables that imaging markers must strive to meet to be useful in these roles.  It also will review the most promising imaging markers available today for evaluating arthritic changes in bone, articular cartilage, and other joint structures and point to areas where further progress can be anticipated.

 

Key References

Altman RD, Hochberg M, Murphy WAJ, Wolfe F, Lequesne M. Atlas of individual radiographic features in osteoarthritis. Osteoarthritis Cartilage 1996;3(suppl. A):3‑70.

Bashir A, Gray ML, Burstein D. Gd‑DTPA as a measure of cartilage degradation. Magn Reson Med 1996;36:665‑673.

Buckland‑Wright JC, Macfarlane DG, Lynch JA, Jasani MK, Bradshaw CR. Joint space width measures cartilage thickness in osteoarthritis of the knee: High resolution plain film and double contrast macroradiographic investigation. Ann Rheum Dis 1995;54:263‑268.

Disler DG, McCauley TR, Kelman CG, Fuchs MD, Ratner LM, Wirth CR, Hospodar PP. Fat‑suppressed three‑dimensional spoiled gradient‑echo MR imaging of hyaline cartilage defects in the knee: Comparison with standard MR imaging and arthroscopy. Am J Rheumatol 1996;167:127‑132.

Peterfy C. Imaging techniques. In: Rheumatology 2d ed. Klippel J, Dieppe P (eds.) Philadelphia: Mosby 1997;1:14.1-14.18.

Peterfy C. Magnetic resonance imaging. Osteoarthritis. In: Brandt K, Doherty M, Lohmander L (eds.) New York: Oxford University Press 1998;473-494.

Peterfy CG, Majumdar S, Lang P, van Dijke CF, Sack K, Genant H. MR imaging of the arthritic knee: Improved discrimination of cartilage, synovium and effusion with pulsed saturation transfer and fat‑suppressed T1‑weighted sequences. Radiology 1994;191:413‑419.

Recht MP, Pirraino DW, Paletta GA, Schils JP, Belhobek GH. Accuracy of fat‑suppressed three‑dimensional spoiled gradient‑echo FLASH MR imaging in the detection of patellofemoral articular cartilage abnormalities. Radiology 1996;198:209‑212.

 

Imaging of Ankylosing Spondylitis

Robert D. Boutin, M.D.

Radiological evaluation of arthropathies is classically based on analysis of two fundamental findings:  the distribution and morphology of osteoarticular abnormalities.  Ankylosing spondylitis (AS) primarily targets synovial and cartilaginous joints, as well as sites of tendinous and ligamentous attachment to bone.   Radiographic abnormalities in patients with AS predominate in the sacroiliac joints and spine, following in descending order of frequency by the hips, glenohumeral joints, knees, hands, wrists, and feet.  In the past, scientific investigations commonly evaluated the efficacy of imaging in providing an accurate diagnosis of early AS.  Although the early and accurate diagnosis of AS is still a primary goal of imaging, other concerns and questions are voiced with increasing frequency.  For example, given the substantial constraints imposed by managed care, how should imaging be utilized to provide a cost‑effective impact on patient care and outcome?  Specifically, what is the optimal imaging algorithm for the assessment of patients?  Other questions focus on more academic (and corporate) concerns:  What is the most sensitive and specific means for detecting response to a new therapy?  Although conventional radiography continues to be the principal method of radiologic assessment, other imaging methods (e.g., magnetic resonance imaging) are expected to be used in the future with increasing frequency to detect pathologic changes involving joints, bones, and entheses.

 

Imaging Technology for Osteoarthritis

Mark E. Brezinski, M.D., Ph.D.

A variety of modalities have now shown feasibility for modifying the progression of articular cartilage damage in osteoarthritis.  This has resulted in a need for better methods to image early changes in cartilage and monitor the progression of these changes.  The advantages and limitations of traditional imaging methods, such as radiography, low‑frequency ultrasound, computed tomography, magnetic resonance imaging, and arthroscopy, for assessing articular cartilage, will be examined.  In addition, newer technologies, such as optical coherence tomography (OCT), will be discussed.  OCT is a new method of high‑resolution imaging that allows distances to be measured on a micron scale.  OCT can be envisioned as analogous to ultrasound, measuring the intensity of backreflected infrared light rather than sound.  All technologies will be discussed with respect to their ability to identify fine changes in the cartilage necessary for monitoring therapeutic modalities.

 

Cytokine Expression in Arthritis

Gary S. Firestein, M.D.

Cytokines play a key role in the perpetuation of rheumatoid arthritis (RA).  Careful studies of the cytokine profile in RA have demonstrated an abundance of macrophage and fibroblasts such as IL‑1, TNF‑alpha, and IL‑6.  Furthermore, production of proinflammatory mediators, including prostaglandins and metalloproteinases, is regulated in rheumatoid synovium by these cytokines.  In an effort to understand the mechanism of action of antirheumatic drugs, surrogate markers for clinical trials have been evaluated.  Although peripheral blood and synovial effusions are more accessible and a few studies have demonstrated clinical correlations with cytokines or soluble cytokine receptors, they are probably less useful than direct examination of synovial tissue.  Serial synovial biopsies to evaluate surrogate markers was first used to examine the effect of steroids and methotrexate on metalloproteinase gene expression. Subsequent studies have demonstrated that blind percutaneous biopsies are essentially equivalent to arthroscopic samples and can be used to evaluate the expression of cytokines.  For instance, methotrexate and anti‑TNF‑alpha therapy significantly decrease synovial expression of cytokines as determined by immunohistochemistry.  This method for assessing cytokine expression is reproducible and has been carefully validated.  Attempts to quantify cytokine mRNA in synovial tissue using nested reverse transcriptase‑polymerase chain reaction are also promising, although no studies to date have directly compared mRNA and protein analyses. Additional studies are required to develop clear criteria for determining the most appropriate techniques for assaying cytokines as well as the best cytokine surrogate endpoints.

 

Key References

Dolhain RJ, Tak PP, Dijkmans BA, De Kuiper P, Breedveld FC, Miltenburg AM. Methotrexate reduces inflammatory cell numbers, expression of monokines and of adhesion molecules in synovial tissue of patients with rheumatoid arthritis. Br J Rheumatol 1998;37:502‑508.

Firestein, GS, Paine M, Boyle DL. Mechanisms of methotrexate action in rheumatoid arthritis:  Selective decrease in synovial collagenase gene expression. Arthritis Rheum 1994;37:193‑200.

Firestein, GS, Paine M, Littman BH.  Gene expression (collagenase, tissue inhibitor of metalloproteinase, complement, and HLA‑DR) in rheumatoid arthritis and osteoarthritis synovium: Quantitative analysis and effect of intra‑articular corticosteroids. Arthritis Rheum 1991;34:1094‑1105.

Kirkham BW, Navarro FJ, Corkill MM, Panayi GS. In vivo analysis of disease modifying drug therapy activity in rheumatoid arthritis by sequential immunohistological analysis of synovial membrane interleukin 1 beta. J Rheumatol 1994;21:1615‑1619.

Kotake S, Schumacher HR Jr, Yarboro CH, Arayssi TK, Pando JA, Kanik KS, Gourley MF, Klippel JH, Wilder RL. In vivo gene expression of type 1 and type 2 cytokines in synovial tissues from patients in early stages of rheumatoid, reactive, and undifferentiated arthritis. Proc Assoc Am Physicians 1997;109:286‑301.

Tak PP, Taylor PC, Breedveld FC, Smeets TJ, Daha MR, Kluin PM, Meinders AE, Maini RN. Decrease in cellularity and expression of adhesion molecules by anti‑tumor necrosis factor alpha monoclonal antibody treatment in patients with rheumatoid arthritis. Arthritis Rheum 1996;39:1077‑1081.

Youssef PP, Kraan M, Breedveld F, Bresnihan B, Cassidy N, Cunnane G, Emery P, Fitzgerald O, Kane D, Lindblad S, Reece R, Veale D, Tak PP Quantitative microscopic analysis of inflammation in rheumatoid arthritis synovial membrane samples selected at arthroscopy compared with samples obtained blindly by needle biopsy. Arthritis Rheum 1998;41:663‑669.

 

Genetic and Major Histocompatibility Complex Markers of Disease Severity in Rheumatoid Arthritis

Cornelia M. Weyand, M.D.

Rheumatoid arthritis (RA) is a chronic inflammatory disease that often leads to disability and crippling.  It is now recognized that RA is a multigene disorder with several genetic risk factors contributing to pathogenesis.  We have proposed that multiple subtypes of RA exist and that different phenotypes of RA correspond to the inheritance of different arrays of disease risk genes.  This concept has been supported by a detailed analysis of the distribution of human leukocyte antigen (HLA)‑DRB1 polymorphisms in patient cohorts, indicating that the clinical heterogeneity in course and outcome correlates with HLA‑DRB1 allelic polymorphisms.  A set of HLA‑DRB1 alleles has been recognized as disease associated, but different alleles are enriched in distinct subtypes of RA.  Rheumatoid factor-positive destructive disease is preferentially associated with the HLA‑DRB1*0401 allele, whereas HLA‑DRB1*0404 and B1*0101 predispose to milder and seronegative disease.  Inheritance of two copies of RA‑associated alleles carries a high risk for extra‑articular spreading of RA.  Homozygosity for HLA‑DRB1*0401 has been reported in patients with the most serious complication of RA, rheumatoid vasculitis.  In addition to HLA‑encoded polymorphisms, abnormalities in the generation and function of CD4 T cells can be useful in dissecting patient subsets with different variants of RA.  In patients with extra‑articular RA, unusual CD4+ lymphocytes emerge that are characterized by a deficiency for the CD28 molecule.  CD4+CD28‑ T cells have a tendency to form large clonal populations, produce high amounts of interferon-gamma, and exhibit autoreactivity.  Accumulation of these CD4 T cells in a subset of RA patients likely reflects a fundamental abnormality in T cell homeostasis.  Appreciation of the heterogeneity of the synovial component of RA has come from studies describing at least three different patterns of lymphoid organization and tissue cytokine production in the synovium of RA patients.  Genetic elements determining disease expression in the inflammatory lesions await identification, but candidate genes include cytokine genes and tissue injury response genes.  The ultimate goal of these studies is to dissect the phenotypic and genotypic heterogeneity of RA and to correlate combinations of disease-risk genes with clinical variants of the disease.  The recognition of clinical subcategories will be required to optimize pathogenic studies and also provide important tools in the diagnostic and therapeutic management of patients with the RA syndrome.

Key References

Klimiuk P, Goronzy JJ, Bjornsson J, Beckenbaugh RD, Weyand CM. Tissue cytokine patterns distinguish variants of rheumatoid synovitis. Am J Pathol 1997;151:1311‑1319.

Schmidt D, Goronzy JJ, Weyand CM. CD4+ CD7‑ CD28‑ T cells are expanded in rheumatoid arthritis and are characterized by autoreactivity. J Clin Invest 1996;97:2027‑2037.

Wagner UG, Koetz K, Weyand CM, Goronzy JJ. Perturbation of the T cell repertoire in rheumatoid arthritis. Proc Natl Acad Sci U S A 1998;95:14447‑14452.

Walser‑Kuntz DR, Weyand CM, Weaver AJ, O'Fallon WM, Goronzy JJ. Mechanisms underlying the formation of the T cell receptor repertoire in rheumatoid arthritis. Immunity 1995;2:597‑605.

Weyand CM, Goronzy JJ. The molecular basis of rheumatoid arthritis. J Mol Med 1997;75:772‑785.

Weyand CM, Goronzy JJ. Pathogenesis of rheumatoid arthritis. Med Clin North Amer 1997;81:29‑55.

Weyand CM, Hicok KC, Conn DL, Goronzy JJ. The influence of HLA‑DRB1 genes on disease severity in rheumatoid arthritis. Ann Intern Med 1992;117:801‑806.

Weyand CM, Klimiuk PA, Goronzy JJ. Heterogeneity of rheumatoid arthritis: From phenotypes to genotypes. Springer Semin Immunopathol 1998;20:5‑22.

Weyand CM, McCarthy TG, Goronzy JJ. Correlation between disease phenotype and genetic heterogeneity in rheumatoid arthritis. J Clin Invest 1995;95:2120‑2126.

Weyand CM, Schmidt D, Wagner U, Goronzy JJ. The influence of sex on the phenotype of rheumatoid arthritis. Arthritis Rheum 1998;41:817‑822.

 

Serum Markers of Joint Metabolism

Eugene J.‑M. A. Thonar, Ph.D.

Fragments produced when molecules are degraded in joints eventually reach the blood circulation where they can be measured by sensitive immunoassays.  The levels of these molecular markers provide critical information concerning the state of health of joint tissues, especially articular cartilage.  Measurements of the markers in joint disease have already proved useful to monitor changes in the metabolism of joint tissues following joint injury and to identify individuals most likely to exhibit rapid joint destruction.  They also can be used to monitor disease progression and to identify drugs capable of inhibiting deleterious processes or promoting repair in articular cartilage.

 

Molecular Markers in Osteoarthritis

Stefan L. Lohmander, M.D., Ph.D.

The identification of individuals at risk for disease progression, the monitoring of outcomes in clinical trials, and the treatment of osteoarthritis (OA) present a challenge.  The lack of readily usable methods hinders progress in the treatment of joint diseases.  Interventions developed in this area concentrate on agents that inhibit proteolytic degradation of the cartilage matrix.  Considerable literature exists on molecular markers in human arthritis and OA (Lohmander et al. 1995, 1998), supporting a relationship between marker concentrations in joint fluid, serum or urine, and cartilage turnover.  This provides face validity for these markers to monitor dynamic changes in the target tissue.  Other aspects of validity for the use of markers are less well supported, but new data suggest that markers will be useful in future trials.  Increased serum concentrations of hyaluronan, C‑reactive protein, and cartilage oligomeric matrix protein predict future OA progression (Månsson et al. 1995; Sharif et al. 1995a, 1995b; Spector et al. 1997), which can be used to select high‑risk individuals in early trials.  Data on within‑ and between‑patient variability for molecular markers in joint fluid and serum and urine are available for stable OA cohorts (Lohmander et al. 1998) and suggest that (1) variability differs between markers in the same compartment, (2) variability is lower within than between patients, and (3) markers are responsive to change.  Some 30 patients per treatment arm would be needed to show a change of 0.5 standard deviation with 80‑percent power (Lohmander et al. 1998).  The final answer on the utility of these surrogate measures must await the availability of an agent that changes OA disease progression.

 

Key References

Lohmander LS, Dahlberg L, Eyre D, Lark M, Thonar EMJ‑A, Ryd L. Longitudinal and cross‑sectional variability in markers of joint metabolism in patients with knee pain and articular cartilage abnormalities. Osteoarthritis Cartilage 1998;6:351‑361.

Lohmander LS, Felson DT. Defining and validating the clinical role of molecular markers in osteoarthritis. In: Osteoarthritis. Brandt KD, Doherty M, Lohmander LS (eds.) Oxford: Oxford University Press, 1998;519-530.

Lohmander LS, Saxne T, Heinegård D, editors. Molecular markers of joint and skeletal diseases. Acta Orthop Scand 1995;66 (suppl):1‑212.

Månsson B, Carey D, Alini M, Ionescu M, Rosenberg LC, Poole AR, Heinegård D, Saxne T. Cartilage and bone metabolism in rheumatoid arthritis. Differences between rapid and slow progression of disease identified by serum markers of cartilage metabolism. J Clin Invest 1995;95:1071‑1077.

Sharif M, George E, Shepstone L, Knudson W, Thonar EJ, Cushnaghan J, Dieppe P. Serum hyaluronic acid level as a predictor of disease progression in osteoarthritis of the knee. Arthritis Rheum 1995a;38:760‑767.

Sharif M, Saxne T, Shepstone L, Kirwan JR, Elson CJ, Heinegård D, Dieppe PA. Relationship between serum cartilage oligomeric matrix protein levels and disease progression in osteoarthritis of the knee joint. Br J Rheumatol 1995b;34:306‑310.

Spector TD, Hart DJ, Nandra D, Doyle DV, Mackillop N, Gallimore JR, Pepys MB. Low‑level increases in serum C‑reactive protein are present in early osteoarthritis of the knee and predict progressive disease. Arthritis Rheum 1997;40:723‑727.

 

Collagen Type II Cross‑Linked Telopeptides:  A Promising Marker of Cartilage Degradation in Arthritis

David Eyre, Ph.D.

A specific cartilage degradation marker has potential value in chondro‑protective drug development and clinical management of arthritis patients.  There is a need for minimally invasive biochemical assays that can assess the rate of cartilage degradation in patients with degenerative joint diseases.  The collagen framework of cartilage turns over extremely slowly in the normal adult, and its gross degradation in articular cartilage is believed to be a critical, irreversible event in osteoarthritis.  A degradation assay for cartilage collagen is particularly desirable.  We describe an advance in developing an immunoassay designed to measure pyridinoline cross‑linked telopeptides from type II collagen in human urine, serum, and synovial fluid.

 

Synovial Fluid Markers of Osteoarthritis

Kenneth D. Brandt, M.D.

Development of potential disease‑modifying osteoarthritis (OA) drugs has prompted efforts to develop outcome measures of OA progression in humans.  Although interest exists in various imaging procedures and arthroscopy, these techniques have not been validated or been proved suitable for use in clinical trials.  Interest has grown, therefore, in biochemical/immunochemical tests for monitoring OA progression.  Given the problems that exist in relating the serum concentration of a cartilage‑derived molecule to events in an index joint, it has been suggested that synovial fluid (SF) measurements may be more useful as markers of disease activity or severity in OA.  However, unless factors that affect the kinetics of removal from the joint are taken into account, the SF concentration of these molecules cannot be a valid quantitative indicator of changes in articular cartilage metabolism.  Although synovitis increases clearance of proteins from the joint space, we found that even after adjustment for the increased clearance rate in the OA knee, the synovial fluid concentration of sulfated glycosaminoglycans (most of which are derived from the cartilage) did not correlate with the severity of concurrent or subsequent cartilage damage.  This emphasizes that the SF concentration of a cartilage‑derived marker is related not only to its clearance but also to other, more proximal variables, such as its rate of degradation, matrix permeability, and the rate of synthetic activity by chondrocytes in the OA cartilage.