Osteoclast-like cells in murine collagen induced arthritis.

OBJECTIVE: To investigate the participation of osteoclast-like bone resorbing cells in the joint destruction of murine collagen induced arthritis (CIA). METHODS: After induction of CIA in DBA/1J mice, a histological time course study was conducted on paw sections stained for tartrate resistant acid phosphatase (TRAP), a marker of osteoclasts. Cells from arthritic paws were cultured in vitro with or without indomethacin (IM) or anti-interleukin 6 neutralizing antibody (anti-IL-6), and stained for TRAP. Levels of prostaglandin E2 (PGE2), IL-1beta, IL-6, and tumor necrosis factor-alpha in the culture supernatants were determined by ELISA. The bone resorbing ability of these cells was examined on dentine slices. In control experiments, cells of normal paws or of arthritic tibiae were cultured in the same manner. RESULTS: TRAP positive osteoclast-like cells were detected late in the development of bone lesions at every eroded front in the pannus-bone and the pannus-subchondral bone junctions of arthritic joints. In vitro, cells of arthritic paws formed bone resorbing osteoclast-like cells spontaneously. However, the control culture failed to form these cells. PGE2 and IL-6 were detected at higher levels in arthritic culture than in control culture. Although both indomethacin and anti-IL-6 reduced osteoclast-like cell formation and indomethacin inhibited PGE2 synthesis, indomethacin failed to reduce IL-6. CONCLUSION: These findings suggest the direct participation of osteoclast-like cells in the joint destruction of CIA, the locally enhanced activity of osteoclast-like cell differentiation in arthritic paws, and the participation of prostaglandins and prostaglandin-independent IL-6 in this differentiation.

Protective effects of D-penicillamine and a thiazole derivative, SM-8849, on pristane-induced arthritis in mice.

To evaluate the antiarthritic properties of a novel thiazole derivative, the drugs SM-8849, D-penicillamine and indomethacin were administered to pristane-injected DBA/1 mice. The mice were treated daily with the agents for 32 weeks, starting from the day of the pristane injection. Treatment with SM-8849 (50 mg/kg) resulted in an amelioration of arthritic disease, as assessed by clinical, radiographic, and histologic examinations. Similar results were obtained in mice treated with 50 mg/kg D-penicillamine, although this disease modifying antirheumatic drug was slightly less effective than the same dose of SM-8849. In contrast, indomethacin at the maximum tolerated dose of 2 mg/kg did not alter the course of the disease. SM-8849 and D-penicillamine were also shown to reduce serum levels of rheumatoid factors and the acute-phase reactant, serum amyloid P component. Indomethacin failed to affect either parameter. Flow cytometric analysis revealed an elevation in the T-cell population that expressed CD44, a marker of murine memory T-cells, in spleens from pristane-injected mice. SM-8849, but not D-penicillamine, prevented the increase in this cell population. These results led us to conclude that pristine-induced arthritis was a useful model for the evaluation of antirheumatic agents, in that using this model, we were able to distinguish disease modifying antirheumatic drugs from nonsteroidal anti-inflammatory drugs. Our findings also indicate that SM-8849 shows antiarthritic activity, with a unique mechanism of action, differing from that of D-penicillamine.

Prevention of spontaneous polyarthritis in NZB/KN mice by treatment with a novel thiazole derivative, SM-8849.

NZB/KN mice spontaneously develop polyarthritis, characterized by infiltration of inflammatory cells into the synovium and destructive damage of articular cartilage and bone. This study was performed to elucidate the effects of a novel thiazole derivative (SM-8849; (4-[1-(2-fluoro-4-biphenylyl)-ethyl]-2-methylamino thiazole) in comparison with the cyclooxygenase inhibitor, indomethacin, on disease development and immune disorders in NZB/KN mice. Mice were treated with SM-8894 (50 mg/kg) or indomethacin (2 mg/kg), starting from two months of age, for seven months. Indomethacin had no inhibitory effect on joint lesions in this model. In contrast, SM-8849 was effective in arresting the progression of arthritis, as confirmed by histologic and radiographic studies. Moreover, SM-8849, but not indomethacin, suppressed rheumatoid factor production. In addition, the population of CD5+ B cells in the peritoneal cavity and spleen was reduced with SM-8849 treatment. These findings suggest that NZB/KN mice are of use in the evaluation of intrinsic antiarthritic activity, independently of cyclooxygenase inhibition. Additionally, the therapeutic value of SM-8849 is strongly suggested by its efficacy in this model.

Suppression of murine collagen-induced arthritis by treatment with a novel thiazole derivative, SM-8849.

The antiarthritic activity of a novel thiazole derivative, SM-8849, was compared with that of indomethacin and D-penicillamine, in mice with collagen-induced arthritis. SM-8849 reduced the incidence and severity of disease in collagen-immunized mice, as assessed by clinical observation. This efficacy was also confirmed by radiographic and histologic studies. Indomethacin produced an apparent reduction of the clinical score, but had only a marginal effect on bone destruction. D-penicillamine did not produce any improvement. Unlike indomethacin and D-penicillamine, SM-8849 reduced the serum levels of anti-type II collagen antibodies. Flow cytometric analysis of spleen cells from arthritic mice revealed an increase in T cells expressing activation antigens (class II antigens) in comparison with normal mice. Treatment with SM-8849, but not indomethacin or D-penicillamine, prevented the increase in Ia-bearing T cells. The results suggest that an effect of SM-8849 on immunocompetent cells may be responsible for the antiarthritic activity of the compound, and this would distinguish its action from that of traditional antirheumatic drugs.

Alteration in progression of murine autoimmune disease by treatment with a novel immunomodulator, SM-8849.

The effects of SM-8849 on the development of autoimmune disease in MRL/Mp-1pr/1pr mice were examined. SM-8849 improved survival as well as renal disease, restored the deficits in splenic cell responsiveness to stimulation by mitogens or conventional antigens, and prevented lymphadenopathy and splenomegaly coincident with a decrease in the number of Thy-1+/Lyt-2-/L3T4- cells. SM-8849 also suppressed the production of the B-cell differentiation factor, possibly with a resulting preferential reduction of autoantibodies. In addition, SM-8849 depressed the production of hydrogen peroxide from macrophages. These results suggest that the administration of SM-8849 to a subject with autoimmune diseases can induce immunological improvements with possible clinical effectiveness.

Monoclonal antibody against bacterial lipopolysaccharide cross-reacts with DNA-histone.

Monoclonal antibodies to bacterial lipopolysaccharide (LPS) were prepared by fusing spleen cells from BALB/c mice immunized with Salmonella Minnesota Re 595 LPS to the mouse myeloma cell line P3U1. One of them, designated RS01, revealed a strong positive antinuclear activity and reacted with DNA-histone. RS01 also bound specifically to Salmonella Minnesota Re 595 LPS and eliminated the biological activity of LPS. The Salmonella completely inhibited the ANA activity of RS01 and DNA-histone blocked the reactivity of RS01 with LPS. Thus, it is clear that an anti-LPS monoclonal antibody, RS01 cross-reacts with DNA-histone.