Stem Cells

Stem cells are undifferentiated biological cells that can differentiate into specialized cells and can divide (through mitosis) to produce more stem cells. They are found in multicellular organisms. In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues. In a developing embryo, stem cells can differentiate into all the specialized cells - ectoderm, endoderm and mesoderm - but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.

There are three known accessible sources of autologous adult stem cells in humans:

Stem cells can also be taken from umbilical cord blood just after birth. Of all stem cell types, autologous harvesting involves the least risk. By definition, autologous cells are obtained from one's own body, just as one may bank his or her own blood for elective surgical procedures.

Adult stem cells are frequently used in medical therapies, for example in bone marrow transplantation. Stem cells can now be artificially grown and transformed (differentiated) into specialized cell types with characteristics consistent with cells of various tissues such as muscles or nerves. Embryonic cell lines and autologous embryonic stem cells generated through Somatic-cell nuclear transfer or dedifferentiation have also been proposed as promising candidates for future therapies. Read More ...

In the News ...

Amniotic fluid is a rich source of stem cells that can now be harvested   Science Daily - December 4, 2017
Amniotic fluid, the protective liquid surrounding an unborn baby, is discarded as medical waste during caesarean section deliveries. However, there is increasing evidence that this fluid is a source of valuable biological material, including stem cells with the potential for use in cell therapy and regenerative medicine. A team of scientists and clinicians has now developed a multi-step method, including a unique collection device and new cell harvesting and processing techniques, that enables term amniotic fluid to be safely harvested for large quantities of cells.

Paralyzed man regains use of arms and hands after experimental stem cell therapy   Science Daily - September 7, 2016
After receiving a stem cell injection into his spine, Kris Boesen, who was paralyzed from his neck to his toes after a car accident, is regaining movement in his extremities and hope for increased independence. The pioneering surgery is the latest example of how the emerging fields of neurorestoration and regenerative medicine may have the potential to improve the lives of thousands of patients who have suffered a severe spinal cord injury.

New diaphragms grown from stem cells offer hope of a cure for common birth defect, possibly future repairs of the heart   Science Daily - December 1, 2015
New diaphragm tissue in rats has been successfully created in the lab using a mixture of stem cells and a 3D scaffold. When transplanted, it has regrown with the same complex mechanical properties of diaphragm muscle. The study offers hope of a cure for a common birth defect and possible future heart muscle repairs.

Stem cell exosomes used to induce damaged mouse hearts to self-repair   Science Daily - June 18, 2015
A little more than a decade ago, researchers discovered that all cells secrete tiny communications modules jammed with an entire work crew of messages for other cells. Today, a team of researchers is harnessing the communications vesicles excreted by stem cells and using them to induce the damaged heart to repair itself.

The 'ultimate' stem cell   PhysOrg - October 30, 2014

In the earliest moments of a mammal's life, the developing ball of cells formed shortly after fertilization 'does as mother says' - it follows a course that has been pre-programmed in the egg by the mother. Extraordinary as this is, what happens then is even more remarkable.

Identifying the source of stem cells   PhysOrg - October 30, 2014
When most animals begin life, cells immediately begin accepting assignments to become a head, tail or a vital organ. However, mammals, including humans, are special. The cells of mammalian embryos get to make a different first choice to become the protective placenta or to commit to forming the baby.

Why age reduces stem cells' ability to repair muscle   Science Daily - September 7, 2014
As we age, stem cells throughout our bodies gradually lose their capacity to repair damage, even from normal wear and tear. Muscle stem cells age, their reduced function is a result of a progressive increase in the activation of a specific signaling pathway. Such pathways transmit information to a cell from the surrounding tissue.

Human Skin Cells Given Stem Cell Properties National Geographic - November 21, 2007

Two teams of scientists have given human skin cells many of the properties of embryonic stem cells - a development that could ease political, ethical, and medical concerns over the highly controversial research topic. Like embryonic stem cells, the new cells - known as induced pluripotent cells - are capable of developing into most types of cells in the body. But the new lines can be created without the use of an embryo.

Female Stem Cells Work Better, According To New Study Science Daily - April 10, 2007
Female stem cells derived from muscle have a greater ability to regenerate skeletal muscle tissue than male cells, according to a study at Children's Hospital of Pittsburgh of UPMC. This finding could have a major impact on the successful development of stem cells as viable therapies for a variety of diseases and conditions.

Stem Cells Grown Without Destroying Human Embryos National Geographic - August 24, 2006

A series of four images shows researchers removing a single cell from an embryo. The procedure involves using a tiny pipette to penetrate the embryo and extract a stem cell. The process does not destroy the embryo. The technique is similar to one used during in vitro fertilization to test a human embryo for genetic abnormalities before it is implanted in a woman's womb.

Scientists make nerve stem cells   BBC - August 16, 2005

Stem cells can be programmed to become many kinds of tissue. The world's first pure nerve stem cells made from human embryonic stem cells has been created by scientists at the Universities of Edinburgh and Milan. It is hoped the newly-created cells will eventually help scientists find new treatments for diseases such as Parkinson's and Alzheimer's.

Stem cells tailored for patients   BBC - May 19, 2005
South Korean scientists say they have made stem cells tailored to match the individual for the first time. Each of the 11 new stem cell lines that they made was created by taking genetic material from the patient and putting it into a donated egg.

Baby teeth provide life-giving stem cells   NZ Herald - December 2004
In future, children will not be putting their early teeth aside for the tooth fairy to collect, but putting them instead into a stem cell bank. Rather than being rewarded with a coin, stem cells within the tooth will be stored to cure them of some of the deadliest afflictions they might suffer half a century later.