HEMATOLOGY EBOOK

A stem cell line is a family of constantly-dividing cells, the product of a single parent group of stem cells. They are obtained from human or animal tissues and can replicate for long periods of time in vitro (“witin glass”, or, commonly, “in the lab”, in an artificial environment). They are frequently used for research relating to embryonic stem cells or cloning entire organisms.

Alternative sources.

Adult stem cell lines isolated from mature tissues are commonly used in stem cell research, as are cells isolated from umbilical cord blood. However, these cells have a genetic imprint of the host they were taken from, thus limiting their therapeutic use in genetic disorders. Also, adult stem cells are not totipotent or pluripotent like embryonic stem cells, but rather more specialized cells that are multipotent. Another source of stemc cells is the iPS (induced pluripotent stem) cell. This process involves reversing the differentiating cell signals that cause a stem cell to specialize. In this way, a somatic cell can be worked backwards into a stem cell. One added advantage of this type of stem is that the pluripotent cell has the same DNA as the donor and can be used therapeutically towards that end without painful bone marrow and spinal cord extraction techniques.

New techniques

Typically, stem cells have been maintained using tissue culture methods that essentially date from the 1950′s. In particular, they are often “fed” using mouse embryonic fibroblasts (“feeder cells”) while being simultaneously suspended in a nutrient sollution (“media”). However, many scientists are recognizing the importance of using media that is completely free of animal ingredients. This not only liberates cell lines from animal feeder cells, but also brings the in vivo therapeutic use of stem cells one step closer to reality.

Nonmammalian Study model

One interesting study model that yields research results that ca be subsequently tested on mammalian systems, is the fruit fly Drosophila (1).