Wednesday, March 26, 2008

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.
  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.

Tuesday, March 18, 2008

Coffee, tea, or a teaspoon of stem cells?

A few years ago, I had surgery that, although could be considered cosmetic, in my case was determined medically necessary and thus covered by my group health insurance from my job.

Fast forward a few years, to when that same job was out-sourced to a third-world country along with my access to health insurance. Would I have undergone the surgery; a surgery that is not life-threatening but in my case definitely life-enhancing?

A growing phenomenon might make my decision easier, or at least a bit titillating.

Medical tourism, a phrase coined to describe a destination vacation coupled with medical treatment sounds as innocuous as tying the knot with a destination wedding.

Websites offer images of sunning on a white sand beach, sipping island drinks and tasting tidbits of exotic foods, while recovery from surgery done at a clinic in Thailand, Argentina, India, or Singapore. Feeling better tomorrow? Tour the local sites and do some shopping.
  • Affordability (lower labor costs)
  • Access to treatments that are not available at home (good by regulations)
  • Fun! (hey, we all need medical treatment sooner or later, why not make lemonade?)
If one is 'adventurous' to embark on these high-stake 'vacations', more power to you. I just hope you have a plan B.

The wonder, excitement, and hope that surround the potential of stem-cell based therapies also puts the most vulnerable of us into peril.

When realized, stem-cell therapies will address the diseases and conditions that have no or minimal prevention, treatment, and cure. Oh glorious day!

Abnormal will become normal again: The paralyzed limb will flex its fine motor neurons, opening and closing fingers. The discombobulated brain will cognate again in Einsteinian precision. Normal is normal is normal is everything,

Unscrupulous 'travel agents' advertise stem cell-based therapy cures for spinal cord, stroke, brain injuries, and so on.

See the Kremlin. Have an injection of stem cells. Reverse the paralysis.

As in any con that reels in the desperate and vulnerable, medical tourism is a high-tech form of selling snake oil.

  • That there is no verifiable stem-cell based therapy as of yet for these conditions doesn't matter. (A spinal cord clinical trial is due to start soon)
  • That most embryonic stem cell research has been done on animal models and needs to be transferred to the human model and then sent to the multi-phased clinical trials period doesn't matter. (There are differences between mice and man)
  • That quality control and effective measurements to determine if the therapy is working need to be in place doesn't matter. (Heparin from China, anyone)
Back to my original question: Would I have undergone the surgery; a surgery that is not life-threatening but in my case definitely life-enhancing?

As much as I want our days to become normal again, I understand the scientific process and the myriad problems that need to be solved before stem cell therapies will be.

Impatient? Yes. Reckless? No.

So my answer to my question is, just book me on a simple, old-fashioned vacation. I'll wait-impatiently-for stem cell therapies to work their way through the scientific process. I won't just be waiting, but I'll be advocating, educating, and learning, putting medical vacations a long weekend at home.

Monday, March 17, 2008

Impact of iPS Cells

When Dr. Jamie Thomson and his team announced their success in reverse-engineering adult skin cells back to the nascent blueprint, embryonic stem cells, I knew there'd be quite a stir.

At first blush, induced pluripotent stem cells (iPS) might be the answer to the ethical conundrum that has stalled federal support of embryonic stem cell research: some feel the "potential for life" (i.e. the small cluster of cells inside the pre-implantation blastocyst) should be afforded the same constellation of human rights and protections that our constitution guarantees an existing, human life.

Adult cells that can be bit-banged back to their defining-formula, may be the answer.

Though, "Is this an instance of genetic-engineering?" comes to mind immediately. Just think of the uproar a few years back concerning genetically-engineered milk! (rBGH - for those of you not from the dairy state).

I can see no end to the ethical, moral, and political debates, not mentioning hard, scientific questions that need answers:
  • what is "potential for life"? how should it be protected?
  • are reversed-engineered adult cells as good as newly minted cells from the blastocyst?
  • how will state and federal monies be divided up to study these approaches?
  • is the 'life' that is engineered through the iPS process 'potential for life'?
  • can iPS be understood without understanding embryonic stem cells?
  • are all the scientists going to abandon embryonic stem cell research for iPS?
  • will politicians chicken out of formulating sound regulatory guidelines for embryonic and induced pluripotent stem cells? at state and federal levels?
Let's hope the hoopla of the last few years is done, and we can move forward in both areas of stem cell research: induced pluripotent and embryonic stem cell research.

There are too many people, suffering from conditions and diseases that have nothing but the hope of a stem-cell therapy breakthrough on the horizon, to allow this to become a duel between two potentially breakthrough technologies.