SYNOPSIS
Goal of regenerative medicine is to reconstruct tissues or organ in the needy part of the body. Discussions of what are the fundamental factors for creating artificially tissues or organ from cells require a certain biochemical and physiological knowledge, accompanying a deep insight into human body. Traditional triad for tissue engineering: (1) cells, (2) matrix and (3) cytokines seem no more enough now-a-day. We have been proposing the five factors: (1) cells, (2) matrices, (3) cytokines, (4) nutrients supply or vasculature and (5) mechano-dynamic factors, the last two of which, so far, has been poorly elucidated in vitro and in vivo situation. In the initial parts of this review, we recapitulate the history of the ‚geometry of the artificial matrices”, which are now understood to be closely related with nutrient supply or vasculature. Then we will step into an important issue of mechano-dynamic factors. So far, cell culture has been studied on static state on stable flat culture dishes. But in a living body, no single cell exists on such a motionless situation. Thus, various devices were invented for providing mechano-dynamic factors to the cells. The most of them are complex and highly expensive for many young researchers to approach. After reviewing several such devices, we introduce a simple application of gravitational forth, so-called ‚ceiling culture or anti-gravitational culture (anti-G-culture)”. In this new culture system, it was shown that RNA of actin fibers increased 20 times higher than the conventional flat dish culture, meaning that in anti-G-culture system, general activities of cells highly enhanced due to a mechano-dynamic factor that is anti-G-force.

Key words: tissue regeneration, extracellular matrix (ECM), geometry, mechano- dynamics, anti-gravitational culture (ceiling culture)