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Induced pluripotent stem cells Our bodies are made of millions of cells that work together to help you think, talk, laugh, run around and stay healthy. Stem cells are one of the most amazing types of cell in the body because they can: 1. self renew – make copies of themselves 2. differentiate – make other types of cells like skin cells, liver cells or red blood cells
Most specialized cells in your body cannot divide to make copies of themselves. You need stem cells to replace specialized cells that die, are damaged or get used up. For example, in your body 2,000,000 new red blood cells are made every second. It’s also important that stem cells make copies of themselves (self-renewal). If they didn’t, your body would quickly run out. You need to maintain a pool of stem cells to use throughout your life. Embryonic stem (ES) cells are taken from inside the blastocyst, a very early stage embryo. The blastocyst is a ball of about 50-100 cells and it is not yet implanted in the womb. It is made up of an outer layer of cells, a fluid-filled space and a group of cells called the inner cell mass. The ES cells are found in the inner cell mass.
ES cells are exciting because they can make all the different types of cell in the body. Scientists say these cells are pluripotent. Because stem cells can make copies of themselves, scientists can use the cells of a single blastocyst and grow them endlessly in the lab; they have made many embryonic stem cell lines. These ES cell lines are stored at a stem cell bank to make sure scientists all over the world can use cells of the same cell line for their experiments without the need to use a new blastocyst every time. Tissue stem cells, also called adult stem cells, are found in the tissues of the body. In a fetus, a baby, a child, and in adults. These stem cells can make copies of themselves and several types of specialized cells, but not all. For example blood stem cells in the bone marrow can make all the different types of cells in your blood, but they can’t make skin cells. Scientists say these tissue stem cells are multipotent. Your body has lots of different types of tissue stem cells. For example, you have neural stem cells in your brain, retinal stem cells in your eye and skin stem cells in your skin.
Recently, scientists have discovered a way to make pluripotent stem cells from normal adult skin or brain cells. These artificially created stem cells are called induced pluripotent stem (iPS) cells and, just like embryonic stem cellls, they can self-renew and can be turned into all the different cell types of the body. The idea of a stem cell came from studies in the late 19th century when scientists realised that some cells could produce other cells. The term ‘stem cell’ was first used by Alexander Maksimov (1874-1928) at a congress of the Hematologic Society in Berlin in 1908. He discovered that some cells could make the cells present in the blood system. Please visit EuroStemCell for more info on stem cells. |
