Master cell research is rapidly gaining interest in Regenerative Medicine.

Regenerative medicine, also known as tissue engineering, is a rapidly growing multi disciplinary field attracting worldwide attention as a major step in advanced medical treatment. Regenerative medicine refers to developing functional cell, tissue, and organ substitutes to repair, replace or enhance biological functions that have been lost due to congenital abnormalities, injury, disease, or aging.

Until now, regenerative medicine had primarily focused on research into ES (embryonic stem) cells ^*1. Human cells in the brain, liver, muscles and other tissues are different from one another; while ES cells can be altered into any type of cell and are thus referred to as master cells. ES cells are derived from human embryos and utilizing these cells for research have caused significant ethical concerns.

• *1Embryo stem (ES) cells: Fertilized mice embryos cells develop into placenta and other tissues in three to five days following fertilization; and there are cell masses that develop into the mouse's body itself. ES cells are established as undifferentiated cell lines in culture outside the mouse's body. ES cells have the ability to transform into various types of cells. Human ES cells were first successfully cultured in 1998.

IPS (induced pluripotent stem) cells are produced by inducing skin cells to revert back into original master cells through a process of activating certain genes. ^*2. For example, cells can be taken from a patient's skin, turned into iPS cells, and after they are transformed into tissue cells, researchers believe it is possible to make 3D structures which organs are made from. Because iPS cells are made from the patient's own skin cells, this process does not face the rejection issue that can occur with organ transplantation. Additionally since iPS cells are made from skin cells, there are no ethical dilemmas as there are with ES cells.

While research into the practical use of iPS cells in medical treatment is continuing, in the area of new drug therapy the use of muscle and liver cells made from iPS cells in drug trial efficacy and side effects is promising.

• *2Induced pluripotent stem (iPS) cells: IPS cells have been given properties similar to ES cells by introducing various types of genes (transcription factors) to somatic cells (mainly fibroblastic cells). These cells were first produced by a research group led by Professor Shinya Yamanaka of Kyoto University.

Principle of phase-difference observation

The APC objective uses the nature of diffracted light ^*3 to widen the angle at which it passes through a tiny cell. Cell detail is made more visible by inserting absorption bands of different transmittances inside and outside the phase ring in the lens. The halo^*4 that appears around the cell makes the cell look brighter if it is darker than the background, or if it is bright, it makes it look much brighter than the background.

With the current BioStation CT, researchers check the condition of samples through the monitor, but Nikon is now developing a new feature that combines Nikon microscope and image analysis technologies to automatically observe close-up changes in cells or time replacement of culture media ^*5. Nikon is also evaluating incorporating a robot for changing culture media. When this new design is realized, automated production of live cell cultures will advance further, enhancing efficiency in regenerative medical treatments and new drug therapy research.

• *3Diffracted light: Light that bends around to the rear of the cell
• *4Halo: a circle of light surrounding a cell
• *5Culture medium: Fluid containing nutrients required for the growth of bacteria or cells