Creation of Stem Cells From Human Testes Marks Another Advance In Stem Cell Research

Sperm-producing cells taken from men’s testicles may be just as adaptable as cells from embryos. A group of European researchers have now found a way to coax cells from the male testes into embryonic-like stem cells.

Embryonic stem cells can grow to practically any tissue in the body, leading scientists to believe they could offer treatments for diseases such as Parkinson's disease and diabetes, as well as be used to heal the body in such ways repairing spinal cord injuries and damage to the heart.

These findings are among the latest of multiple studies conducted to find a way of duplicating embryonic stem cell behavior. There have been impressive experiments in reprogramming ordinary body cells into stem cells by inserting certain genes into them.

In 2008 alone, advances have been made in stem cell research with human cloning and the use of skin and bone marrow cells, as well as menstrual blood, in the quest to alter cells to become ones that mimic embryonic cells. Scientists have also had success in altering mature cells to act like embryonic stem cells.

Advances have also recently been made in targeting certain cells to learn more about specific conditions and diseases such as the use of heart stem cells to repair cardiac related conditions and duplicating stem cells from ALS patients to study and learn the cause of the disease in hopes of using the knowledge to find a cure.

Use of the testicular cells steers clear of the ethical dilemma of using embryonic stem cells, which require the destruction of embryos to be harvested. As stated by lead study author Thomas Skutella, a professor at the Center for Regenerative Biology and Medicine in Tuebingen, Germany, "The advantage these cells have in comparison to embryonic stem cells is that there is no ethical problem with these cells and that they are natural."

The new type of stem cells created from the testes of men could be used to grow personalized replacement tissues. However, because the cells come from men, the benefits would also apply to men. Skutella said a female equivalent could possibly be found in women's egg cells.

Although prior studies have shown promise in the use of spermatogonial cells (primitive male germ cells) from the testes of mice, the new study used cells taken from biopsied tissue from 22 men, ages 17 to 81, with various medical conditions. The researchers found that the cells could differentiate into various types of cells like those taken from embryos after only a few weeks of growth. The study was recently published in the journal Nature.

Skutella and colleagues report, "We have developed a culture method for establishing human adult germline stem cells from testicular biopsies. These cells changed their properties, losing characteristics of spermatogonial cells and acquiring characteristics similar to those of human embryonic stem cells."

The new cells were more like embryonic stem cells than sperm cells at the genetic level. When these cells were injected into immune-compromised mice, they produced a tumor that contains many different kinds of cells known as teratomas and when grown in culture dishes, they could be directed to differentiate into muscle, bone, neurons, and pancreatic tissues.

There are, of course, still obstacles to face. In one recent study where human embryonic stem cells were injected into healthy mice, the immune system’s response, recognizing the cells as foreign, was to destroy them. Even when an autoimmune compound was used in hopes of preventing the body’s rejection, although the lifetime of the new cells was extended, the end result was the same. More studies will have to be conducted to determine if a compromised immune system would react in the same way.