Stem Cell Transplant
C Vermylen, et al (Univ of Louvain, Brussels, Belgium; Univ of Brussels, Belgium; Univ Hosp, Gent, Belgium et al) Haematopoietic Stem Cell Transplantation for Sickle Cell Anaemia :The first 50 patients transplanted in Belgium.
Bone Marrow Transplatn 22:1-6, 1998.
Stem cell transplantation can eradicate sickle cell anemia. Because the best outcomes are achieved in very young patients, parents should be informed that bone marrow transplantation offers the best chance of cure, given the availability of a familial HLA-compatible donor.
Ann E Traynor, James Schroeder, et al (Division of Immunotherapy for Autoimmune Diseases, Northwestern University Chicago, USA)
Treatment of severe systemic lupus erythematosus with high-dose chemotherapy and haemopoietic stem-cell transplantation: a phase I study.
The Lancet, vol.356, August 26, 2000. Pg.701-707.
Patients with SLE and persistent multiorgan dysfunction, inspite of IV cyclophosphamide, have a high risk of early death. In this study, safety and efficacy of immune suppression and autologous haemopoietic stem-cell infusion was investigated.
Seven selected patients with persistent SLE despite use of cyclophosphamide, underwent immune-suppression and autologous haemopoietic stem-cell (CD34) infusion. They mobilised autologous haemopoietic stem cells with cyclophosphamide and granulocyte colony stimulating factor, enriched with CD34-positive selection and reinfused after immunosuppression with cyclo phosphamide, methylprednisolone and equine antithymocyte globulin.
At a median follow-up of 25 months, all patients were free from signs of lupus. renal, cardiac, pulmonary and serological markers and T-cell phenotype and repertoire had normalized. Durability of remission remains to be established.
Irving L. Weissman
Stem Cells – Scientific, Medical, and Political Issues
New Engl Jr Med. Vol.346, May 16, 2002, pg.1576-79
Stem cells have the unique capacity not only to give rise to more stem cells (self-renewal) but also to generate differentiated progeny. They are present at all stages of development and probably exist in all multicellular organisms. In the blastocyst stage of the embryo before implantation, the inner cell mass contains cells that will become the fetus. Some of these cells are pluripotent stem cells that give rise to all types of somatic and germ-line cells. When these pluripotent cells are grown in vitro, they become embryonic stem cell lines.
The developmental stages between pluripotent embryonic cells and multipotent tissue-specific stem cells, such as hematopoietic stem cells, are still unclear. Pluripotent stem cells generate germ-line stem cells plus tissue-specific stem cells.
Multipotent tissue-specific stem cells can be found from the fetal stage onward. In adults, they can participate in the renewal and regeneration of tissue, and during fetal life they may be units of tissue generation.
Critical properties of stem cells – self-renewal and differentiation – should be the gold standard for all such studies.
The author believes that using the currently available embryonic stem-cell lines to delineate developmental lineages of human cells will be extremely valuable. Knowledge gained from such studies should spawn a search for molecules or factors that cause particular cells to follow particular pathways and inhibit them from following others.
How could such stem-cell lines be generated? One way is by transferring somatic-cell nuclei into enucleated eggs (nuclear transplantation). When stimulated to divide, the cell can form blastocysts of predefined nuclear genotype (with the mitochondrial DNA coming from the egg). Cells from the inner cell mass of these blastocysts can be isolated, cultured, and used to generate embryonic stem-cell lines of predefined genotype.
It is possible that religious and ethical considerations will lead to a ban on such research, because of the fear that nuclear transplantation into enucleated eggs might be used to clone a human being.
For some segments of society, blastocysts produced by nuclear transplantation are embryos to be accorded full human rights, and their destruction or biopsy to produce embryonic stem-cell lines constitutes the taking of lives.
The author believes that such research will be as valuable to medicine as recombinant DNA research has proved to be.