Stem Cell Report – July/August 2000

Date: 09/02/2000

Human Bone Marrow Stem Cells Can Form Liver

Two new studies from scientists in the United States and the United Kingdom have independently shown that human adult stem cells from bone marrow can generate new liver tissue. (Previous work with mice had shown that adult bone marrow stem cells could form liver, as well as bone, cartilage, tendon, nerve and other tissues.) These new studies with human patients raise the possibility that patients needing a liver transplant could instead use their own bone marrow stem cells, or even adult stem cells circulating in the blood, to regenerate liver tissue. Dr. Nick Wright, professor at the Imperial Cancer Research Fund, said the findings turned on its head the notion that adult stem cells can only develop into cells associated with one tissue: “If you had said this sort of thing three years ago, you would have been laughed out of court.” Dr. Neil Theise, professor of pathology at New York University School of Medicine, said of the findings: “My fallback position now is that any cell that contains the entire genome–and most cells do–has the potential to turn on any aspect of that genome and be any [kind of] cell.” Dr. Malcolm Alison of the British team noted that: “Adult stem cells offer great promise in medicine as they may generate the full spectrum of cell types needed to repair a damaged organ.”

Dr. Wright also noted: “There is a shortage of livers to transplant but there is a lot of concern over using embryo stem cells to repopulate liver. Our technique has no such ethical limitations.” He added that since patients could use their own stem cells, “We could avoid problems with current liver transplants where the patient’s body rejects the foreign organ.” According to Dr. Markus Grompe, professor of molecular medical genetics at Oregon Health Sciences University: “This would suggest that maybe you don’t need any type of fetal stem cell at all–that our adult bodies continue to have stem cells that can do this stuff.”1

Adult Bone Marrow Stem Cells Can Generate Nerve Cells

Adult bone marrow stem cells have previously been shown to have the ability to “re-program” themselves as numerous other tissues, including bone, cartilage, connective tissue, skeletal muscle, liver, and glial cells. Now scientists at the University of South Florida College of Medicine have shown that these versatile adult stem cells also appear able to form neurons. When they cultured human or mouse adult bone marrow stem cells with specific growth factors, the cells converted into immature nerve cells. Dr. Juan Sanchez-Ramos, lead scientist on the project, noted that “It’s striking that we can generate new kinds of cells from deep within the bone, including cells with the potential to become neurons for brain repair.” These adult stem cells could prove to be an easily-obtainable and ethical source for nerve cells to treat Parkinson’s disease, stroke, and other neurodegenerative disorders. Layton BioScience Inc. has licensed the rights to this technology and is developing it for clinical use.2

Large Numbers of Adult Bone Marrow Stem Cells Can Be Generated in Culture

Bone marrow stem cells have proven to be one of the most useful and adaptable adult stem cells, and have been used clinically for numerous treatments. One critique leveled at these adult stem cells has been that large numbers of cells could not be generated in culture. Now the conditions have been identified to allow large-scale expansion of adult stem cells in culture, making these cells an almost unlimited source. Researchers in Philadelphia achieved a billion-fold increase in a few weeks for bone marrow stem cells in culture. These results open the way to even more useful clinical applications of adult stem cells.3

Adult Bone Marrow Cells Can Form Multiple Tissue Types

Researchers with Osiris Therapeutics and Johns Hopkins University have shown that adult stem cells from human bone marrow have the capacity to regenerate not only more bone marrow, but also numerous other tissue types as well. In culture, the cells were stimulated to form either bone, cartilage, or fat cells. The cells appear to have the potential to form other tissues as well, including tendon and muscle. The ability to specifically stimulate these adult stem cells to form differentiate tissues opens up multiple therapeutic applications.4

  1. Neil Theise et al. Liver from Bone Marrow in Humans”; Hepatology 32, 11-16, July, 2000; Malcolm Alison et al.; Cell Differentiation: Hepatocytes from Non-Hepatic Adult Stem Cells”; Nature 406, 257, July 20, 2000; Susan Okie, Bone Marrow Stem Cells Offer Hope for Liver Therapies; Study of Transplants Shows a Transformation”; Washington Post, June 27, 2000; Dr. David Whitehouse, Stem cells promise liver repair”; BBC, July 19, 2000; Neil Theise et al.; Derivation of hepatocytes from bone marrow cells in mice after radiation-induced myeloablation”; Hepatology 31, 235-240, January, 2000; Bryon Petersen et al.; Bone marrow as a potential source of hepatic oval cells”; Science 284, 1168-1170; May 14, 1999.
  2. J. Sanchez-Ramos et al.; Adult Bone Marrow Stromal Cells Differentiate into Neural Cells in Vitro”; Experimental Neurology 164, 247-256.
  3. David Colter et al.; Rapid expansion of recycling stem cells in cultures of plastic-adherent cells from human bone marrow”; Proceedings of the National Academy of Sciences, USA 97, 3213-3218, March 28, 2000.
  4. M.F. Pittenger et al.; Multilineage potential of adult human mesenchymal stem cells”; Science 284, 143-147, April 2, 1999.