acid-phosphatase and Arthritis--Juvenile

Topics: Acid Phosphatase; Arthritis, Juvenile; Bone Marrow; Bone Marrow Cells; Hexosamines; Humans; L-Lactate Dehydrogenase; Plasma Cells; Proteins; Rheumatoid Factor; Synovial Fluid

Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) can cause severe growth disturbances of the craniomandibular system. Antigen-induced arthritis (AIA) of the rabbit TMJ is simulating the inflammatory process of the TMJ in JIA. The aim of this study was to investigate the effect of a systemic administration of the tumor necrosis factor-alpha (TNF-α) antagonist etanercept on AIA in rabbits by means of three different histological staining methods.. After sensitization, a bilateral arthritis of the TMJ was induced and maintained by repeated intra-articular administrations of ovalbumin in 12 New Zealand white rabbits aged 10 weeks. From the 13th week of age, 6 of the 12 rabbits received weekly subcutaneous injections of etanercept, and the other 6 animals remained without therapy. Another 6 animals served as controls, receiving no treatment or intra-articular injections at all. After euthanasia at the age of 22 weeks, all TMJs were retrieved en bloc. Sagittal sections were cut and stained with hematoxylin-eosin (H-E), Safranin-O for the evaluation of the Mankin score, and tartrate-resistant acid phosphatase (TRAP).. In the arthritis group, a chronic inflammation with degeneration of the articular cartilage was visible. In the etanercept group, the signs of cartilage degeneration were significantly reduced but present. In contrast, the joints in the control group were inconspicuous. A strong correlation between the Mankin score and TRAP-positive cells could be found.. Antigen-induced arthritis causes severe damage in the TMJ of young rabbits. An improvement seems to be achievable by a systemic administration of etanercept.

Topics: Acid Phosphatase; Animals; Anti-Inflammatory Agents, Non-Steroidal; Arthritis, Experimental; Arthritis, Juvenile; Biomarkers; Cartilage, Articular; Coloring Agents; Disease Models, Animal; Etanercept; Female; Freund's Adjuvant; Injections, Intra-Articular; Injections, Subcutaneous; Isoenzymes; Mandibular Condyle; Osteoclasts; Ovalbumin; Phenazines; Rabbits; Random Allocation; Tartrate-Resistant Acid Phosphatase; Temporomandibular Joint Disorders; Time Factors

Focal resorption of bone at the bone-pannus interface is common in rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) and can result in significant morbidity. However, the specific cellular and hormonal mechanisms involved in this process are not well established. We examined tissue sections from areas of bone erosion in patients with RA and JRA. Multinucleated cells (MNCs) were present in resorption lacunae in areas of calcified cartilage and in subchondral bone immediately adjacent to calcified cartilage, as previously described. mRNA for the calcitonin receptor (CTR) was localized to these MNCs in bone resorption lacunae, a finding that definitively identifies these cells as osteoclasts. These MNCs were also positive for tartrate-resistant acid phosphatase (TRAP) mRNA and TRAP enzymatic activity. Occasional mononuclear cells on the bone surface were also CTR positive. Mononuclear cells and MNCs not on bone surfaces were CTR negative. The restriction of CTR-positive cells to the surface of mineralized tissues suggests that bone and/or calcified cartilage provide signals that are critical for the differentiation of hematopoietic osteoclast precursors to fully differentiated osteoclasts. Some MNCs and mononuclear cells off bone and within invading tissues were TRAP positive. These cells likely represent the precursors of the CTR-TRAP-positive cells on bone. Parathyroid hormone receptor mRNA was present in cells with the phenotypic appearance of osteoblasts, in close proximity to MNCs, and in occasional cells within pannus tissue, but not in the MNCs in bone resorption lacunae. These findings demonstrate that osteoclasts within the rheumatoid lesion do not express parathyroid hormone receptor. In conclusion, the resorbing cells in RA exhibit a definitive osteoclastic phenotype, suggesting that pharmacological agents that inhibit osteoclast recruitment or activity are rational targets for blocking focal bone erosion in patients with RA and JRA.

Topics: Acid Phosphatase; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Arthritis, Juvenile; Arthritis, Rheumatoid; Biomarkers; Bone Resorption; Humans; Immunohistochemistry; In Situ Hybridization; Isoenzymes; Macrophages; Osteoclasts; Receptors, Parathyroid Hormone; RNA, Messenger; Tartrate-Resistant Acid Phosphatase

Topics: Acid Phosphatase; Adolescent; Arthritis, Juvenile; Child; Child, Preschool; Female; Glucuronidase; Humans; Lysosomes; Male

Topics: Acid Phosphatase; Adolescent; Alkaline Phosphatase; Arthritis, Juvenile; Child; Child, Preschool; Glycogen; Humans; Neutrophils; Peroxidase; Phagocytosis

Topics: Acid Phosphatase; Adolescent; Adult; Arthritis, Juvenile; Arthritis, Rheumatoid; Aspartate Aminotransferases; Fructose-Bisphosphate Aldolase; Humans; L-Lactate Dehydrogenase; Leucyl Aminopeptidase; Malate Dehydrogenase; Synovial Fluid

Topics: Acid Phosphatase; Adolescent; Arthritis, Juvenile; Child; Child, Preschool; Follow-Up Studies; Humans; Infant; Rheumatoid Factor; Synovial Fluid