However, many scientists disagree with this and admit they are uneasy about therapeutic cloning². Other scientists point out the dangers of embryonic stem cell transplants. Dr Lorraine Young, of the Roslin Institute, has revealed that 80 per-cent of cloned animals have abnormally high birth weights. She observed that "twice the average birth-weight for the breed is not uncommon" and that in some cases cloned lambs have been three or four times larger than would have been the case naturally. Commenting on the implications for therapeutic cloning of human embryos, Dr Young continued: "Some of the genes that may cause these defects in cattle and sheep we know are involved in tumour production in humans. It is possible that when you transplant this tissue into patients you could introduce cancer"³.

Studies on adult stem cells in the last 30 years have shown that many adult tissues contain stem cells and in recent years, pluripotent stem cells capable of producing a variety of cells, have been discovered in various human tissues, such as bone marrow, the brain, connective tissues of various organs, and the umbilical cord⁴. It has been found that live neural stem cells can be obtained from adult cadavers even hours or days after death⁵.

The progress and results from adult stem cell research show their flexibility and their many possible uses, probably no different from those of embryonic stem cells, since plasticity depends upon genetic information, which can be reprogrammed. For example, Dr. Micheline Mathews of Harvard Medical School has cured a rare genetic disease in mice by inserting the missing gene into their own stem cells. In April 2000, French researchers reported in Science what was described as the first clear success in human gene therapy, curing severe combined immunodeficiency disease (SCID) in several children by inserting the missing gene into their bone marrow stem cells.

Adult stem cells only become different types of cell when they are given new signals to do so. Placed in their usual environment, they seem to produce only the cell types of that particular tissue which is exactly what is needed to repair such tissue safely. Therefore, "besides skirting the ethical dilemmas surrounding research on embryonic and foetal stem cells, adult cells... might have another advantage: They may be easier to manage"⁶.

Researchers at the University of Texas have reported⁷that the enzyme telomerase can "immortalise" adult cell cultures without producing the uncontrolled growth of cancer cells. Another researcher was able to multiply human bone marrow stem cells a billion-fold in six weeks⁸.

There have been many developments in the field of adult stem cell technology recently, particularly since the British parliament voted to authorise research on embryonic stem cells on the incorrect basis that it was "the only hope anywhere on the horizon"⁹. In the first four months of 2001 researchers in Cambridge claimed to have developed a way of converting fully developed adult cells into stem cells¹⁰; scientists in California succeeded in converting fat tissue into muscle, bone and cartilage¹¹; a company in New Jersey claimed to have developed a new technique for obtaining a plentiful supply of stem cells from the placenta expelled by the mother after childbirth¹²; a conference in the United States heard how stem cells from umbilical cords had been successfully used to treat strokes in rats¹³; doctors in Canada treated a nine month-old child who had cancer with stem cells extracted from his umbilical cord¹⁴; the company which cloned Dolly the sheep announced that it had succeeded in converting skin tissue from cows into beating heart cells; and researchers in Sheffield and Cardiff reportedly discovered a way of regenerating bone and brain cells¹⁵.

Commercial companies recognise the possibilities of adult stem cell technology. Osiris Therapeutics, Inc., is a private company in Baltimore, USA, which focuses on the restoration of damaged and diseased tissue. Osiris uses adult bone marrow to isolate, purify and grow human mesenchymal stem cells (hMSCs), the pro-genitor cells that lead to connective tissues including bone marrow stroma, bone, cartilage, ligament, tendon and fat, as well as muscle. They believe that hMSC cell therapy will prove effective treatment for damage arising from injury, ageing or degenerative diseases¹⁶.

1 House of Commons Hansard, 19 December 2000, Column 260
2 Such as Dr John Wyatt, professor of neonatal paediatrics at the Royal Free and University College Medical School in London, who said: "I and many of my fellow health professionals share a profound disquiet about the introduction of therapeutic cloning. Many of us are actively involved in research to find novel therapies for life threatening and disabling conditions." (Quoted by Lord Alton; House of Lords Hansard, 22 January 2001, column 29)
3 Daily Telegraph, 1 August 2000
4 Cf. C. S. POTTEN (ed.), Stem Cells, Academic Press, London 1997, p. 474; D. ORLIC, T. A. BOCK, L. KANZ, Hemopoietic Stem Cells: Biology and Transplantation, Ann. N. Y. Acad. Sciences, vol. 872, New York 1999, p. 405; M. F. PITTENGER, A. M. MACKAY, S.C. BECK et al., Multilineage Potential of Adult Human Mesenchymal Stem Cells, Science 1999, 284, 143-147; C. R. R. BJORNSON, R.L. RIETZE, B. A. REYNOLDS et al., Turning Brain into Blood: a Hematopoietic Fate Adopted by Adult Neural Stem Cells in vivo, Science 1999, 283, 534- 536; V. OUREDNIK, J. OUREDNIK, K. I. PARK, E. Y. SNYDER, Neural Stem Cells - a Versatile Tool for Cell Replacement and Gene Therapy in the Central Nervous System, Clinical Genetics 1999, 56, 267-278; I. LEMISCHKA, Searching for Stem Cell Regulatory Molecules: Some General Thoughts and Possible Approaches, Ann. N.Y. Acad. Sci. 1999, 872, 274-288; H. H. GAGE, Mammalian Neural Stem Cells, Science 2000, 287, 1433-1438; D. L. CLARKE, C. B. JOHANSSON, J. FRISEN et al., Generalized Potential of Adult Neural Stem Cells, Science 2000, 288, 1660-1663; G. VOGEL, Brain Cells Reveal Surprising Versatility, ibid., 1559-1561.
5 UniSci, 28 April 1999
6 G. Vogel, in Science, 25 February 2000
7 In Nature Genetics, January 1999
8 Dr Darwin Prockop (now at Tulane University) in Proceedings of the National Academy of Sciences, 28 March 2000.
9 Ms Yvette Cooper’s concluding speech, op.cit.
10 Dr Ilham Abuljadayel, reported in The Times, 15 January 2001
11 Research team led by Marc Hendrick of the University of California at Los Angeles; reported in The Times and the Independent, 10 April 2001
12 John Haines, chief executive of Anthrogenesis Corp. of Cedar Knolls, New Jersey, said that he thought his company’s discovery would make the use of embryos as a source of stem cells obsolete; reported by the Catholic News Service, 11 April 2001, and in the Minneapolis Star Tribune, 12 April 2001.
13 Professor Paul Sanberg of the University of South Florida at the annual meeting of the American Association for the Advancement of Science; reported on BBC News online, 18 February 2001
14 Reported by LifeSite, Canada, 5 April 2001
15 Dr Bradley Singer of Sheffield University and Dr George Foster of Cardiff University; reported in The Times, 26 January 2001
16 From the mission statement on Osiris Therapeutics’ website: www.osiristx.com

'A Way of Life' The Society for the Protection of Unborn Children March 2002

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