Functions of organism last properly depending on well organized and controlled reproduction, immigration, differentiation and maturation activities unions. It is possible when the cells in organ and tissues are produced regularly. Stem cells are at the top of this system in an organism. Stem cell is that are able to renew themselves by keeping on splitting for long time by remaining same (not differentiated) and they can differentiate according to needs of organism. Stem cells are major source of cell based treatments. Thus some of researches are using human or animal based stem cells from different kind of tissues.

In different kinds of stem cell researches state that mature stem cell have some significant advantage on the cure of damaged tissues. The advantage of using stem cell obtained from an adult is that stem cell can reproduce in patients own cultivation and then before facing regeneration, they can be given to the patient.

Stem cell researches and its treatments are still the very popular topic in the world

STEM CELLS AND WHY ARE THEY IMPORTANT?

Research of stem cell has gained much prominence in recent years for its therapeutic potential in dealing with diseases many of which are essentially incurable by normal therapies. These diseases are characterized by progressive cell loss which has no regenerative potential: e.g. neurodegenerative process leads to Alzheimer and Parkinson diseases. These have become serious health problems as people in advanced societies now live longer. There is great variability in the occurrence and onset of these diseases and the underlying environmental and genetic factors are unknown. The destruction of the beta cells of pancreatic islets is the main cause of diabetes, another serious health problem, can be caused by autoimmune reactions resulting in cell loss (1).

Stem cells are distinct from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity (in G0). Second, under certain physiologic or experimental setting, they can be induced to become tissue or organ specific cells with special functions (2). In some organs, stem cells regularly divide to repair and replace worn out or damaged tissues such as the gut and bone marrow. In other organs, however, such as the heart and the pancreas, stem cells only divide under special conditions. They have the remarkable potential to develop into many different cell types in the body during early life and growth. On the other hand, they serve as a sort of internal repair system in many tissues, dividing essentially without limit to replenish other cells as long as the person or animal is still alive (2).

Scientists frequently worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic somatic or adult stem cells. Researchers discovered ways to derive embryonic stem cells from early mouse embryos nearly 30 years ago, in 1981. In 1998, the detailed study of the biology of mouse stem cells led to the discovery of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. They are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lung, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease (2,3).

In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be reprogrammed genetically to assume a stem cell-like state. This new type of stem cell was called induced pluripotent stem cells (iPSCs) (2).

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Stem Cell « Medical Research Center