In recent years, various kinds of molecular targeted drugs, such as anti-TNFα monoclonal antibody (mAb), anti-IL-6 receptor mAb, CTLA4-Ig, and JAK inhibitor, have been used in the treatment of rheumatoid arthritis. Despite differences in the molecular targets of these drugs, they strongly inhibit bone erosion and synovitis even in patients with high-level clinical disease. Recent basic studies have revealed that these molecular targeted drugs exert direct effects on osteoclast differentiation and function, although little is known about the differences in mode of action.
We have originally established an advanced imaging system for evaluating the in vivo pharmacological actions of drugs in living mice using intravital multiphoton microscopy. By means of this system, we revealed that different molecular targeted drugs acted at specific therapeutic points during osteoclastic bone destruction with different efficacies. These results enable us to grasp the real modes of action of drugs, optimizing the usage of drug regimens. We are now establishing a novel imaging system for analyzing the pathogenesis of fibrotic diseases, which could serve as the basis for developing novel anti-fibrotic therapies.
In this symposium, we show the latest data, and also discuss the further application of intravital imaging techniques.