Of mice or men

Encouraging research this week from Memorial Sloan-Kettering Cancer Center spotlights therapeutic cloning as potential treatment for Parkinson’s disease.

Therapeutic cloning also known as somatic cell nuclear transfer is politically-controversial. Some fear a gang of young Hitlers as in Boys from Brazil will spring forth from this exciting and hopeful technique.

Let's take a look at what somatic cell nuclear transfer is and what it might do.

What is somatic cell nuclear transfer? Here's a simple recipe-no advanced cell biology needed-that describes the process.

Somatic Cell Nuclear Transfer recipe:
Prep Work:

• The nucleus of a cell contains the genetic material.
• The somatic cell is any body cell except the sex cells, sperm or egg.
• The somatic cell is taken from the diseased individual or lab animal.
• Extracting the nucleus from a cell is like separating the yolk from the white of an egg.
• Cells without a nucleus are referred to as enucleated cells.
• The egg referred to in the steps below is a donor egg.
• A blastocyst is a mass of cells from which embryonic stem cells can be acquired.

Steps:

1. Extract the nucleus from the egg.
2. Extract the nucleus from the somatic cell.
3. In a small petri dish, place the enucleated egg and insert the somatic cell's nucleus.
4. Apply electrical stimulation to the mix until cell division generates the blastocyst.
5. Isolate stem cells from the inner cell mass of the blastocyst to cultivate an embryonic stem cell line.
   

What’s so special about this?

The cultivated stem cell lines can be differentiated into specific type cells to be transplanted to the diseased person. And, since the stem cells are created from the SCNT process, the correct genetic material is carried forth. This may reduce the transplant rejection problem.

Hold on to your whiskers! Why is this important?

To move from the bench, the research environment and animal models, to the clinic with usable and safe cell therapies, the problem of the immune system-rejection after a transplant must be mitigated.

This is what makes somatic cell nuclear transfer so special. These cells are YOUR cells genetically!

What was done to the mice to give us hope?

Using a Parkinson’s disease mouse mode, somatic skin cells from the mouse’s tail were used to generate a specific cell type – the dopamine neurons, that are depleted in Parkinson’s disease. These new dopamine neurons are autologous, derived from one’s own body.

The results?

Mice that were given the somatic cell nuclear transfer cells neurologically improved. Mice that did not genetically match the somatic cell nuclear transfer cells, did NOT improve and the grafted cells themselves did not survive.

The future:

Somatic cell nuclear transfer or therapeutic cloning seems to work in an animal model. We need to prove it works in the human model. Unfortunately, too often animal model therapies do not neatly translate to the human model.