Stem cells (SCs) are blank slate cells. They have the following properties: they can divide and renew themselves ; they are unspecialized, meaning they have not yet become a specific tissue type; and they are capable of becoming specialized cell types. In the adult, they function as tissue repair cells, hustling over to areas of injury to help with the healing process. The process that makes this possible is the proliferation effect. SCs can multiply and renew themselves almost indefinitely.

Also, when placed in certain environments with special stimuli, they can be induced to become specific organs.

The types of SCs that have received the most publicity are the embryonic stem cells. As their name suggests, these cells are derived from human embryos. When the embryo is approximately 5 days old, it consists of a number of SCs. This is called the blastocyst phase. The cells within the embryo are capable of differentiating into- or becoming- any type of organ system. While the differentiation capacity for these types of cells makes them extremely attractive for scientific use, the source- the human embryo- has made these cells a lightning rod for ethicists and politicians. Also, the proliferation effect is particularly strong in the embryonic stem cell. The “braking” mechanism seems problematic … and this gives rise to fears of uncontrolled proliferation, also known as cancer.

More recently, scientists in a number of labs have been able to take adult cells and reprogram the genetic machinery so that the cells essentially become blank slate cells. These are called induced pluripotential SCs.

They resemble embryonic SCs in their ability to differentiate into any organ system.

Even in the normal adult, there are reservoirs of SCs located within the bone marrow, deciduous teeth, muscle, and periosteum of bone, that are capable of replacing normal cells lost as a result of aging or injury.

This property of normal adult SCs makes them valuable and unique. While the technical term used to refer to them is autologous SCs, they are often called “repair SCs.”

A final group of SCs that have been used for medical purposes are the allogeneic SCs. These are SCs harvested from healthy donors. While they have been found to be extremely effective, the theoretical possibility of overlooking genetic disorders that might be transmitted by these SCs makes them less appealing.

The value of SCs resides not only in their reparative abilities. By using stem cell models, scientists can also investigate the cause of birth defects as well as test new medications.

So what causes SCs to differentiate? What makes them become a certain tissue type? The answer is not fully known yet. However, the answer almost assuredly lies in the genetic makeup of the cell. This genetic makeup can be influenced by external factors. What these factors are also remains shrouded in mystery. But it appears that when a stem cell is surrounded by a certain tissue type and then exposed to growth factors, it tends to proliferate into the tissue it is in closest proximity to.

This makes them particularly appealing to work with when it comes to the treatment of certain degenerative conditions such as arthritis.

Nathan Wei, MD FACP FACR is a board-certified rheumatologist and nationally known arthritis authority and expert. For more info: Arthritis Treatment and Arthritis Treatment Center

Nathan Wei, MD FACP FACR is a board-certified rheumatologist and nationally known arthritis authority and expert. He is a former consultant to the National Institutes of Health and clinical assistant professor of medicine at the University of Maryland School of Medicine. http://arthritistreatmentcenter.com

Author Bio: Nathan Wei, MD FACP FACR is a board-certified rheumatologist and nationally known arthritis authority and expert. For more info: Arthritis Treatment and Arthritis Treatment Center

Category: Medicines and Remedies
Keywords: stem cells, arthritis treatment, embryonic stem cells, autologous stem cells, allogeneic stem cells