Stem Cell Report – Fall 2002

Date: 10/02/2002

“Therapeutic” Cloning No Longer Needed, Says Leading Embryonic Stem Cell Scientist

Alan Trounson, Australian embryonic stem cell expert and a leader in the field worldwide, says that stem cell research (both adult and embryonic) has advanced so rapidly in the past few months that therapeutic cloning is now unnecessary. “My view is there are at least three or four other alternatives that are more attractive already,” he said. Professor Trounson said therapeutic cloning faces logistical problems, and that other techniques are showing great promise and offer better options. 1

Adult Stem Cells More Effective Than Embryonic Stem Cells in Blood Formation

Because hematopoietic (blood forming) stem cells (HSCs) can restore and maintain blood formation following transplantation into immune deficient hosts, growth of HSCs in culture is important for many clinical applications. Previously, researchers in Sweden used a gene therapy technique to add a growth gene to embryonic stem cells to get adequate growth in culture. According to the authors, however, “HSCs of early embryonic origin, including those derived from differentiated embryonic stem cells, are inefficient in engrafting adult recipients upon transplantation.” The researchers have now shown that adding the same growth gene, Lhx2, to adult bone marrow stem cells allows unlimited growth of the cells. These adult stem cells efficiently rescued immune-compromised mice and generated all blood cells.2

Adult Bone Marrow Stem Cells Show Immune Tolerance, Not Rejected

Researchers in Canada and Japan have shown in animal studies that adult stem cells from bone marrow have a unique immunity tolerance. When selected bone marrow stem cells of mice were injected into rats, without immunosuppression, the injected cells survived and thrived without being rejected by the host immune system. The cells incorporated not only into bone marrow but also into damaged heart to aid repair.3

Adult Stem Cells Stimulated to Form Insulin-Secreting Pancreatic Cells

Scientists at Massachusetts General Hospital have successfully turned adult stem cells into insulin-producing cells that could reverse diabetes. They found that treating adult stem cells in the pancreas with a naturally occurring hormone can transform the stem cells into beta cells, which secrete insulin. This means new beta cells could be made from a patient’s own pancreatic stem cells to treat their diabetes.4

Adult Bone Marrow Stem Cells Can Repair Retina

Adult bone marrow stem cells injected into the eyes of rats with damaged retinas formed new retinal cells. The bone marrow stem cells incorporated and differentiated into retinal neural cells in the injured retina. Bone marrow stem cells may be useful in repair of damaged retinal cells.5

Adult Bone Marrow Stem Cells Could Prevent Blindness, Grow New Blood Vessels

Scientists at Scripps Research Institute used bone marrow stem cells to grow new blood vessels in the eyes of mice, a development researchers say could lead to treatments for some forms of blindness in humans, including diabetic retinopathy and macular degeneration. The injected adult stem cells homed in on the parts of the eye where they were needed, grew new blood vessels, and prevented blindness in the mice. Diabetic retinopathy is the leading cause of blindness in working age Americans, and age-related macular degeneration is a common cause of vision loss in people over age 60. Both conditions are caused by damaged retinal blood vessels.

Adult Bone Marrow Stem Cells Stimulate Growth in Children With Bone Disease

Adult bone marrow stem cells implanted into children with osteogenesis imperfecta, a severe bone and cartilage disease, have stimulated growth of bone in these patients. During the 6 months immediately following the transplant, the children’s growth reached 60% to 94% of expected normal values for children their age.

  1. Tom Noble, “Stem-cell cloning not needed, says scientist, The Age Melbourne), pg. 2, July 29, 2002; Jim Buckell, “Stem-cell research outpaces cloning, The Australian, pg. 3, July 29, 2002; “Therapeutic cloning no longer necessary: expert, AAP Newsfeed, July 29, 2002.
  2. Ó. P. do Pinto, et al. “Hematopoietic Progenitor/Stem Cells Immortalized by Lhx2 Generate Functional Hematopoietic Cells in vivo in Blood 99, 3939-3946; June 1, 2002.
  3. T. Saito, et al.; “Xenotransplant Cardiac Chimera: Immune Tolerance of Adult Stem Cells in Annals of Thoracic Surgery 74, 19-24; July 2002.
  4. E.J Abraham, et al. “Insulinotropic Hormone Glucagon-Like Peptide-1 Differentiation of Human Pancreatic Islet-Derived Progenitor Cells into Insulin-Producing Cells in Endocrinology 143, 3152-3161; August 2002.
  5. M. Tomita, et al. “Bone Marrow-Derived Stem Cells Can Differentiate into Retinal Cells in Injured Rat Retina in Stem Cells 20, 279-283; July 2002.