Human Embryonic Stem Cells
October 29 and November 5, 2002

Readings:

NIH Stem Cell primer: May 2000
NIH Lifts Stem Cell Funding Ban, Issues Guidelines : 9/18/00
NIH Publishes Final Guidelines for Stem Cell Research : January 2001
George Bush - primetime address to the nation: 8/9/2001
AAAs Policy Brief: Stem Cell Research 9/21/2001 - an excellent and up-to-date review. Many of the headings below contain links to the quotes in this review.

I. The Breakthrough: Derivation of hES Cells

Human Embryonic Stem cell research hit the press in November 1998 when researchers first reported the isolation of human embryonic stem (hES) cells derived from two different labs. hES cells, which are derived from ~four-day-old embryos, or from the developing germ cells in fetuses, can differentiate into virtually any type of human cell, from blood cells to skin cells. (For a great review, see the recent National Institutes of Health (NIH) report Stem Cells: Scientific Progress and Future Research Directions, executive summary. Note: a PDF)

Human embryonic development, days 1-5...

UW - Madison Press Release: Wisconsin scientists culture elusive embryonic stem cells

• James A. Thomson, Science, Nov. 6 1998; derived hES cells from surplus IVF blastocysts (shown here on the cover of Time Magazine, August 20, 2001)

John's Hopkins Press Release: Hopkins Research Team Cultures Long-Awaited Human Embryonic Stem Cells

• John Gearhart, PNAS: derived hEG cells (human embryonic germ cells) from human fetal tissue (5-9 weeks gestation)

II. Characteristics of Human Embryonic Stem Cells:

1. Pluripotency. hES cells can form virtually any cell in the body. All three cellular layers, including the lining of the gut and blood vesels (endoderm); cartilage, bone, and smooth and striated muscle (mesoderm); neural tissue and skin (ectoderm) have been produced.

2. Self-renewing. Using in vitro cell culture, hES cells can propagate indefinitely in the undifferentiated state without losing pluripotency.

3. Telomerase expression. Telomerase is an RNA-dependent DNA polymerase whose function diminishes in aging cells and whose expression, when re-activated in normal cells, allows their continual proliferation. hES cells express telomerase. The continual telomerase expression conveys replicative immortality. Other stem cells express telomerase at low levels and thus stop dividing, age, and die with time.

4. Normal chromosome structure (karyotype). hES cells maintain a normal set of chromosomes (46, XX or XY) even after prolonged tissue culture. They do not have additions, deletions or rearrangements in their chromosomal structure as is characteristic of cell lines immortalized by viruses.

Question: Are hES cells totipotent? Well, wouldn't we like to know....!

III. Funding for Research on hES cells 1995-1999

Thompson's and Gearharts' work was not eligible for NIH funding because of a 1995 ban placed on NIH-funded human embryo research by Congress. The following is from appropriations bill H.R.3424, Sec. 510:

'(a) None of the funds made available in this Act may be used for--
      (1) the creation of a human embryo or embryos for research purposes; or
      (2) research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death
(b) For purposes of this section, the term `human embryo or embryos' includes any organism, not protected as a human subject, that is derived by fertilization, parthenogenesis, cloning, or any other means from one or more human gametes or human diploid cells.'

The work WAS funded in 1996 by the biotechnology company, Geron, Menlo Park CA.

Pres and CEO Thomas Okarma, MD, PhD, formerly of Stanford University School of Medicine: "Geron is focused on developing products to treat age-related degenerative diseases. The availability of hES cells opens extraordinary opportunities for tissue transplantation, and for developing cell and gene therapy products with breakthrough medical potential. Further, Geron's proprietary telomerase technology for prolonging the replicative lifespan of cells derived from hES cells positions the company to potentially supply the preferred cells for transplantation medicine."

Any Patents held by Geron...oh, just a few here and there...... (((!!!!YIKES!!!!!))

Primate embryonic stem cells US Patent 5,843,780: (12/01/98)

Inventors: Thomson; James A. (Madison, WI)
Assignee: Wisconsin Alumni Research Foundation (WARF, Madison, WI)
Exclusive license: to Geron
Note October 3, 2001: Patent held by WARF, exclusive license to Geron; some legal troubles here (10/03/01) and there (11/1/01)...of course

Telomerase US Patent 6,093,809: (7/25/00)

Inventors: Cech; Thomas R. (Boulder, CO) [Nobel Prize winner] et al.
Assignees: University Technology Corporation (Boulder, CO); Geron Corporation (Menlo Park, CA)

Oocytes as recipients of nuclear transfer US Patent 6,147,276: (11/14/00)

Inventors: Wilmut; Ian (Midlothian, GB), et al. (ie Scientific father of cloning - Dolly the sheep)
Assignee: The Roslin Institute (Edinburgh) (Midlothian, GB); [Oh, and guess what, the Roslin Institute is now owned by...Geron]

IV. Potential Benefits of hES to Science and Medicine

1. Human Organ and Tissue Transplantation. The potential medical impact of hES cells is huge because of their capability to produce virtually unlimited quantities of any cell in the body. In addition, they have the potential to be genetically engineered. The kinds of cells alreaday derived from hES ells include:

i. Cardiomyocytes. Possible use: replace heart muscle damaged by injury, ischemia, congestive heart failure.

ii. Hematopoietic stem cells. Possible use: obtain blood-forming cells for BMTs.

iii. Endothelial cells. Possible use: re-line blood vessels to treat atherosclerosis (650,000 deaths annually in the US) and arterial insufficuency, or for generating new blood vessels in the heart, brain, or extremities.

iv. Islet cells. Possible use: Treatment for the over 1.4 million people in the US with Insulin Dependant Diabetes Mellitus. Should this approach work, it could result in a lifelong cure for this IDDM. An October 2001 article in The Scientist explores progress, reearch and sources of Islet stem cells. 9/24/02 Wired: New article on Stem Islet cells

v. Neurons. Possible use: Neurons for the treatment of Parkinsons disease (1 million affected in the US), Stroke (500,000 affected in the US), and Alzheimers disease (over 4 million affected in the US).

vi. Fibroblast and keratinocyte skin cells. Possible use: wound healing, burn treatment..

vii. Chondrocytes. Possible use: cartilage replacement in osteoarthritis (16 million Americans affected) , or rheumatoid arthritis (2 million Americans affected) .

2. Pharmaceutical research and development. hES calls could provide permanent, stable sources of normal human differentiated cells to be used for drug screening and testing, drug toxicology, new drug target identification.

3. Human reproductive and developmental biology. hES cells offer a unique way to understand embryonic development, tissue differentiation and repair.

V. Ethical Issues in hES Cells

"In vitro fertilization (IVF) clinics routinely create more human embryos than are needed over the course of a fertility treatment, and are therefore left with excess embryos which are often simply discarded. These surplus embryos are the source of hES cells.

"Opponents of hES cell research: human life begins as soon as an egg is fertilized, a human embryo is a human being. Any research that involves the destruction of a human embryo, regardless of the life-saving potential of the treatments derived from these cells, is morally wrong.

"Proponents of hES cell research: a fertilized egg may have the potential for human life but cannot be considered equivalent to a human being until it has at least been successfully implanted in a woman's uterus. It is morally permissible to use surplus embryos, which would be discarded otherwise, for potentially life-saving biomedical research."

Groups Supporting Embryonic Stem Cell Research: No surprises here

Groups Opposed to Embryonic Stem Cell Research: No surprises here either!

VI. The New NIH Guidelines (Clinton Administration, August 23, 2000)

Because of the tremendous potential of hES cells, NIH appealed to HHS on whether or not the 1995 ban applied to ES cell research. In January 1999, HHS determined that federal funds could be used for research on ES cells as long as they were not used for the derivation of the cells, the process that results in the destruction of an embryo.

President Clinton requested a review of stem cell research by the National Bioethics Advisory Commission (NBAC), which released a report entitled Ethical Issues in Human Stem Cell Research. The report concluded that the federal government should fund research on, and the derivation of, human ES cells, provided that only surplus embryos leftover from IVF were used. It proposed that Congress make an exception to its embryo research ban for the derivation of ES cells.

The NIH Guidelines, August 23, 2000, updated January 2001, detail the documentation and assurances that must accompany requests for NIH funding for research using human pluripotent stem cells derived from human embryos or fetal tissue:

1. For studies using cells derived from human embryos, NIH funds may be used only if the cells were derived from frozen embryos that were created for the purposes of fertility treatment and were in excess of clinical need.

2. The Guidelines prohibit the use of inducements, monetary or otherwise, for the donation of the embryo. There must also have been a clear separation between the fertility treatment and the decision to donate embryos for this research.

3. Investigators who propose to use human pluripotent stem cells from fetal tissue will be expected to follow both the Guidelines and all laws and regulations governing human fetal tissue and human fetal tissue transplantation research.

4. The Guidelines require that the informed consent specify whether or not information that could identify the donor(s) will be retained.

5. They require that the donation of human embryos or fetal tissue be made without any restriction regarding the individual(s) who may be the recipient of the cells derived from the human pluripotent stem cells for transplantation.

6. They also require review and approval of the derivation protocol by an Institutional Review Board.

7. The informed consent should include statements that the embryos or fetal tissue will be used to derive human pluripotent stem cells for research, that may include human transplantation research; that derived cells may be kept for many years; that the research is not intended to provide direct medical benefit to the donor; and, for cells derived from embryos, that embryos donated will not be transferred to a woman's uterus and will not survive the stem cell derivation process.

8. The informed consent must also state the possibility that the results of the research may have commercial potential, and that the donor will not receive any benefits from any such future commercial development.

Areas of Research Ineligible for NIH Funding: As required by law, NIH funds cannot be used for the derivation of pluripotent stem cells from human embryos. The Guidelines also set forth several other areas of research that are ineligible for NIH funding, including:

1. research in which human pluripotent stem cells are utilized to create or contribute to a human embryo;
2. research utilizing pluripotent stem cells that were derived from human embryos created for research purposes;
3. research in which human pluripotent stem cells are derived using somatic cell nuclear transfer;
4. research utilizing human pluripotent stem cells that were derived using somatic cell nuclear transfer;
5. research in which human pluripotent stem cells are combined with an animal embryo;
6. research in which human pluripotent stem cells are derived using somatic cell nuclear transfer for the purposes of reproductive cloning of a human.

VII. Election 2000 and beyond:

Campaign Trail: President Bush said, "I oppose federal funding for stem cell research that involves destroying living human embryos." Most thought that if elected President, Bush would overturn the NIH Guidelines.

April 2001: After the election, the president did not overturn the NIH Guidelines outright but instead ordered a review by HHS Secretary Tommy Thompson. In April, NIH canceled - without explanation - the first scheduled meeting of its committee set up to review grant applications for stem cell research. (4/24/01 Stem cell funding delay). Meanwhile, the public press about hES grew stronger...

August 2001: In his first primetime address to the nation on August 9, 2001, Bush decides to allow federal funding of ES cell research to go forward, but only on cell lines already in existence. In this case, he deemes hES research permissible because destruction of an embryo had already taken place. Bush refused to allow research new cell lines to prevent the federal government from 'acting in a way that encourages the destruction of human embryos'.

64 Cell Lines?: Key to President Bush's decision wasthe NIH's determination hat there were 64 cell lines in existence worldwide as of August 9. Previously, most scientists had thought the number to be much lower. On August 27, 2001, NIH released a statement listing the 64 cell lines and announcing plans to create the Human Embryonic Stem Cell Registry. The NIH also encouraged researchers to submit grant applications for ES cell research.

On November 7, 2001, the NIH posted information about the NIH Stem Cell Registry.

The president also announced the formation of the President's Council on Bioethics, chaired by Dr. Leon Kass, a bioethicist from the University of Chicago. In addition to studying a range of ethical issues raised in the biomedical and behavioral sciences, the council will oversee all federally funded ES cell research. The President's Council on Bioethics began on November 28. 2001 (Executive Order 13237).

The 64 cell lines in existence as of August 9, 2001 at the following ten laboratories: Be sure to LOOK at this chart!

Many scientists have raised concerns about these cell lines centering on five questions:

• Whether the cell lines are indeed healthy stem cell colonies. Maintaining ES cell lines is tricky - with much testing required to check the health and identity of the cell lines. There is some doubt about whether the 64 cell lines met the necessary criteria. Most scientists (October 2001) would say there are ~24-25 lines at best.
• Whether the procedures used to create the hES cells are consistent with high ethical standards. Do all of the 64 cell lines "meet the President's criteria, derived from an embryo that was created for reproductive purposes and was no longer needed," and "informed consent must have been obtained for the donation of the embryo and that donation must not have involved financial inducements." ?
• Whether the different cell lines have sufficient genetic diversity. Researchers will need to carry out experiments on cells derived from a group of embryos that are genetically variable. This will require multiple, independently derived cell lines.
• Whether cells produced from the cell lines would be safe for implantation in humans; Most of the cells have been grown in culture on mouse stem cell feeder layers, which raises the possibility of introducing animal viruses dangerous to humans. Under FDA rules, transplants with existing hES cells would be classified as "xenotransplants," or transplants of animal tissue, and would be subject to strict requirements on both researchers and patients.
• Whether the owners of the cell lines will make them available to researchers in a timely fashion and at a reasonable cost. The NIH had signed a memorandum of understanding with WiCell Research Institute, which is affiliated with the Wisconisn Alumni Research Foundation. The agreement provides WiCell's stem cell lines for federally funded research and allows investigators to freely publish their results.

As more becomes known about the 64 cell lines identified by NIH, the future of federally funded ES cell research will become clearer. President Bush has vowed to veto any legislation that would loosen his restrictions (ie deriving new cell lines).

• Thinking about submitting an NIH grant for your work on hES cells? Here's the FAQs!
• Are scientists happy with the way federally funded stem cell research is going? Generally yes, but not everyone agrees!
• 9/23/2002: CA 'puts out the welcome mat' for stem cell researchers . California Governor Grey Davis signs into law a bill that encourages stem cell research, even to derive new cell lines, with finding from the state of California...

VIII. Finally, what about Adult Stem Cells?
From Adult Stem Cells: November 2001 Tech Review

"While the hES story has been unfolding, adult stem cells, have quietly been been developing in many academic labs and biotech companies. Adult stem cells are found in tissues throughout the body, BUT in very lack characteristics of hES cells. "For certain diseases, adult cells appear very promising, for hepatic and cardiac diseases in particular," says Ronald McKay, a researcher at the National Institutes of Health. "However, if you're asking for a solution to Parkinson's disease or diabetes, I would say the cells that offer the best way are fetal and embryonic." Still, adult stem cells are already being tested in human clinical trials.

"Adult stem cells are more biologically versatile, and capable of adopting more cellular fates, than anyone previously thought. Adult skin stem cells can develop into fat, muscle and neural cells. The bone marrow mesenchymal stem cell can form not only bone and cartilage, but also muscle, tendon, fat and stroma inside bones. In mice, transplanted bone-marrow-derived stem cells can migrate to the brain and develop into cells with characteristics of neurons. These studies reinforce the notion that the adult body maintains a reserve of stem cells, certainly in the bone marrow and probably in many other tissues as well—although the supplies seem to dwindle with age." [Image from 10/26/01 article from HMS Beagle article about Curis]

Biotech companies Researching Adult Stem Cells:

A few other Human and Animal Stem Cell Biotech Companies: NEW 11/26/01

Aastrom Biosciences (ASTM) Adult Stem Cells: "methods for out-of-body stem-cell collection and expansion using umbilical-cord blood for treating breast cancer. It will also help pediatric leukemia patients replenish bone marrow stem cells after radiotherapy or chemotherapy."      
Dendreon's (DNDN) "novel therapeutics via the innovative manipulation of the human immune system" - stem-cell enrichment device isolates certain stem cells from blood for transplantation in cancer patients after high-dose chemotherapy or radiation therapy.
Thermogenesis (KOOL) Chill out those stem cells...Thermogenesis is in the business of preserving stem cells.
Advanced Tissue Sciences (ATIS) has patents covering methods for human based tissue engineering - stem cells to engineer tissues for blood vessels.
Advanced Cell Technology of Worcester, Mass (more about these guys next time!!!!)

Wondering what to do with Baby's Cord Blood? Umbilical stem cells

Objectives:

1. What are the 4 characteristics of hES cells that make them a unique and useful human tissue?
2. List the 3 main uses of hES cells in medicine and science. Give specific examples of tissue types.
3. Explain the difference between totipotent and pleuripotent. Are hES cells totipotent or pleuripotent?
4. Describe the protocol for the derivation of hES cells.
5. Describe the new NIH guidelines (8/2000) for use of hES cells - and areas ineligible for use.
6. Describe President Bush's policy on hES cells.
7. Explain the 5 issues scientists have raised concerning the 64 cell lines
8. What are adult stem cells, and why might they be more useful than hES cells?

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