Adult
Also known as somatic (from Greek Σωματικóς, "of the body") stem cells and germline (giving rise to gametes) stem cells, they can be found in children, as well as adults.
Pluripotent adult stem cells are rare and generally small in number but can be found in a number of tissues including umbilical cord blood. Bone marrow has been found to be one of the rich sources of adult stem cells which have been used in treating several conditions including Spinal cord injury, Liver Cirrhosis, Chronic Limb Ischemia and Endstage heart failure. The bone marrow stem cell quantity has been found to be declining with age and in reproductive age group of females it is relatively lesser than in males of same age group. A great deal of adult stem cell research to date has had the aim of characterizing the capacity of the cells to divide or self-renew indefinitely and their differentiation potential. In mice, pluripotent stem cells are directly generated from adult fibroblast cultures. Unfortunately, many mice do not live long with stem cell organs.
Most adult stem cells are lineage-restricted (multipotent) and are generally referred to by their tissue origin (mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, dental pulp stem cell, etc.).
Adult stem cell treatments have been successfully used for many years to treat leukemia and related bone/blood cancers through bone marrow transplants. Adult stem cells are also used in veterinary medicine to treat tendon and ligament injuries in horses.
The use of adult stem cells in research and therapy is not as controversial as the use of embryonic stem cells, because the production of adult stem cells does not require the destruction of an embryo. Additionally, in instances where adult stem cells are obtained from the intended recipient (an autograft), the risk of rejection is essentially non-existent. Consequently, more US government funding is being provided for adult stem cell research.
An extremely rich source for adult mesenchymal stem cells is the developing tooth bud of the mandibular third molar. The stem cells eventually form enamel (ectoderm), dentin, periodontal ligament, blood vessels, dental pulp, nervous tissues, and a minimum of 29 different end organs. Because of extreme ease in collection at 8–10 years of age before calcification and minimal to no morbidity, these will probably constitute a major source of cells for personal banking, research and current or future therapies. These stem cells have been shown capable of producing hepatocytes.
Read more about this topic: Stem Cell
Famous quotes containing the word adult:
“They are not callow like the young of most birds, but more perfectly developed and precocious even than chickens. The remarkably adult yet innocent expression of their open and serene eyes is very memorable. All intelligence seems reflected in them. They suggest not merely the purity of infancy, but a wisdom clarified by experience. Such an eye was not born when the bird was, but is coeval with the sky it reflects. The woods do not yield another such a gem.”
—Henry David Thoreau (1817–1862)
“[University students] hated the hypocrisy of adult society, the rigidity of its political institutions, the impersonality of its bureaucracies. They sought to create a society that places human values before materialistic ones, that has a little less head and a little more heart, that is dominated by self-interest and loves its neighbor more. And they were persuaded that group protest of a militant nature would advance those goals.”
—Muriel Beadle (b. 1915)
“The confusion of emotions with behavior causes no end of unnecessary trouble to both adults and children. Behavior can be commanded; emotions can’t. An adult can put controls on a child’s behavior—at least part of the time—but how do you put controls on what a child feels? An adult can impose controls on his own behavior—if he’s grown up—but how does he order what he feels?”
—Leontine Young (20th century)