Stem Cells and Cloning David C Hess M

Stem Cells and Cloning David C. Hess M. D. Professor and Chairman Department of Neurology Medical College of Georgia

Advances in medical treatment and health n n Sanitation, clean drinking water Infectious diseases: vaccinations, antibiotics Advances in coronary heart diseasestatins, blood pressure control; cancer treatment Regenerative medicine

Regenerative Medicine n n “Hottest” area in medicine Focus of HHS and NIH planning Worldwide interest Biotechnology companies entering field

Regeneration in urodele amphibians

Target Diseases n n Spinal cord injury Parkinson’s disease Stroke Amyotrophic Lateral Sclerosis (Lou Gehrig’s Disease) n Myocardial infarction (heart attack) Congestive Heart Failure n Diabetes mellitus (juvenile form) n

Why all the recent attention? n n James Thompson (University of Wisconsin) established human embryonic stem cell line in 1998 Flurry of reports showing plasticity of adult stem cells (1998 -

Degeneration and Regeneration of the Nervous System (Ramon y Cajal, 1913) n n “In adult centres, the nerve paths are something fixed, ended, immobile. Everything may die, nothing may be regenerated. ” “It is for the science of the future to change, if possible, this harsh decree. ”

Neurogenesis in human brain n n Old dogma was “no new neurons” Study in cancer patients treated with Brd. U showing neurogenesis in dentate gyrus in late adulthood (Eriksson, Nat Med 1998; 4: 1313)

Erikkson P, Nat Medicine 1998; 4: 1313

Slaying of Dogma n n No new neurons in brain in adulthood (in man) No crossing of germ layers in adults

Cell Therapy: How it works n n Replace damaged cells Stimulate recovery by secreting growth factors -“Trophic factory”

Cell Therapy: sources n n n n Marrow stromal cells Multipotent adult progenitor cells (MAPC) Human umbilical cord stem cells Hematopoietic stem cells Neural stem cells Embryonic stem cells Nuclear transplantation/embryonic stem cells

NEJM 2003; 349: 283

NEJM 2003; 349: 272

Problems with embryonic stem cells n n Rejection (seen as foreign by host) Form teratomas

NEJM 2003; 349: 280

Problems with cloning (nuclear transplantation) n n n Usually fails (requires many oocytes) Faulty genetic reprogramming of cell (born clones have obvious or subtle abnormalities) Issue of mitochondrial DNA (not a perfect match-some mitochondrial DNA comes from mother or oocyte)

Biological roadblock to human cloning (Science 2003; 300: 297) n n Fundamental obstacle to cloning of primate cells It is almost as if someone “drew a sharp line between old world primates-including peopleand other animals saying, ‘I’ll let you clone cattle, mice, sheep, even rabbits and cats, but monkeys and humans require something more. ’”- Gerald Schatten, Univ Pittsburgh

Biological obstacle to primate cloning Simerly et al Science 2003; 300: 297; Science 2003; 300: 225

Cloning “Alamogordo” n n South Korean scientists publish “recipe” for human cloning (isolate embryonic stem cell line from a human clone) Effort applauded by scientists

U. S. Legislative and Executive Action n n August 9, 2001 President Bush allowed federal funding for “pre-existing” human embryonic stem cell lines Federal and State legislative agreement that reproductive cloning should be banned and criminalized

Cloning Legislation n n Human Cloning Prohibition Act of 2003 (Rep Weldon H. R 534) passed House on Feb 27, 2003 with vote of 241 -155. Outlaws therapeutic cloning Similar bill introduced into Senate by Sen Brownback (S 245)

Hatch Bill n The Human Cloning Ban and Stem Cell Research Protection Act of 2003 (S. 303) allows nuclear transfer but outlaws the implantation of the products into “a uterus or the functional equivalent of a uterus”

Laws throughout the world n n Germany, Austria, Ireland, and Italy forbid destruction of embryos Great Britain, Sweden, Israel, Singapore allow (encourage)

European Union n n July 9, 2003 European Commission proposed rules that allow EU research funds to derive new ES lines from embryos “left over” from fertility clinics EU Council of Ministers will have final say in Fall 2003

Recent developments n n June 2003 AMA endorses human cloning for “research” July 17, 2003 New England Journal of Medicine articles and Editorial encouraging “therapeutic cloning” and plan to seek out embryonic stem cell studies to publish

New Jersey cloning law S 1909 n n Permits therapeutic cloning Forbids “reproductive cloning” or bringing a clone to “term” but does not forbid clone to be implanted in a uterus and developed for “parts”

Funding of human embryonic stem cells and cloning n n n New Jersey Governor plans to fund California planning taxpayer funding Harvard University: 100 million Stanford University Univ of California San Francisco 10 million donation

Respect for Life (Donum Vitae) 1987 n “To use human embryos or foetuses as the object or instrument of experimentation constitutes a crime against their dignity as human beings having a right to the same respect that is due to the child already born and to every human person. ” n “The practice of keeping alive human embryos in vivo or in vitro for experimental or commercial purposes is totally opposed to human dignity. “

Donum Vitae 1987 n Human embryos obtained in vitro are human beings and subjects with rights: their dignity and right to life must be respected from the first moment of their existence. It is immoral to produce human embryos destined to be exploited as disposable "biological material".

Donum Vitae, 1987 n Also, attempts or hypotheses for obtaining a human being without any connection with sexuality through "twin fission", cloning or parthenogenesis are to be considered contrary to the moral law, since they are in opposition to the dignity both of human procreation and of the conjugal union.

Declaration of Helsinki and Nuremberg Codes n n Protect human research subjects Forbid doing deadly harm to a human Minimize risks to humans Alternatives always sought before risk to human incurred

Human cloning: why it is wrong n n Creation of embryo with intent to destroy; “strip mining” of stem cells; “commodification” of human life “Therapeutic” cloning will lead inevitably to reproductive cloning Problem with oocyte supply Clones may be defective because of incomplete reprogramming of genome

The ALTERNATIVE

Adult Stem cells n n n Blood, bone marrow Skin Neural (brain)

Bone marrow and blood as a source of stem cells n “The blood is the life” Deut 12: 23 n Regenerative effect of blood n Bone marrow- the “fountain of youth”?

Putative bone marrow populations involved in repair after stroke

MAPC differentiate into endoderm, mesoderm, and ectoderm

Multipotent adult progenitor cells n n n Isolated form human bone marrow A subpopulation of marrow stromal cells Differentiate into virtually every cell type in vitro and in vivo All the positive attributes of embryonic stem cells Do not form teratomas

Bone marrow/blood sources of stem cells n n Umbilical cord stem cells Multipotent Adult Progenitor Cells Marrow stromal cells CD 34, CD 133 cells mobilized into peripheral blood

NIH Stem Cell Website

Adult stem cells home to area of injury NEJM 2003; 349: 273

Cell and Restorative Therapy of Stroke Patient (Lancet 2002; 359: 1047 -54)

Advantages of adult stem cells n n n Autologous (in some cases) No tissue rejection No ethical concerns No teratoma formation Easy to obtain (bone marrow aspirate) Widely available

Disadvantages (criticism) of adult stem cells n n Some “plasticity” or “transdifferentiation” may be simply a result of cell fusion Not as “pluripotential” as embryonic stem cells

Counter to criticism n n Not all results can be explained by cell fusion. Fusion does occur in liver but liver cells are often multinuclear MAPCs can give rise to cells of all germ layers and appear to have same potential as embryonic stem cells (and do not form teratomas)

Clinical trials of adult stem cells n n Published small trials of bone marrow cells in patients with myocardial infarction (heart attack) Ongoing trial of bone marrow cells in patents with heart failure

Aims of ethical research n n n Reprogram an adult cell to become a “stem cell” without step of becoming a human embryo Isolate the “universal” stem cell from adult (MAPC? ) PROPOSE “ethical” regenerative medicine