The country’s first "saviour sibling", a healthy boy whose discarded umbilical cord will help heal one of his two siblings from a genetic blood disease, has brought complicated ethical issues over biotechnology to the forefront in France.
France’s first so-called "saviour sibling" was born in a hospital in the Parisian suburb of Clamart in late January, doctors announced Tuesday. The baby, whose blood stem cells will help cure one of his siblings from a severe genetic blood disease, has also opened a new front in the bioethics debate in France.
Born to parents of Turkish origin and named Umut Talha (Turkish for "our hope"), the child was conceived under circumstances that would have been unthinkable only a generation ago.
Umut Talha’s parents approached the hospital in Clamart a little more than a year ago with a serious problem: their two young children were both afflicted with an inherited blood disorder, Beta thalassemia, which requires monthly blood transfusions. The parents knew the hospital was one of only three in France that was developing a treatment for their children's illness.
An embryo was screened and genetically selected from an original group of 12 embryos. It was picked to ensure it did not carry the gene for Beta thalassemia, but also based on its compatibility with the sick siblings. Besides selecting an offspring that would be spared from the disorder, the parents hoped the future baby would also become a donor of the right kind of treatment cells.
In the end the boy was born disorder-free, and his cells were confirmed to be compatible with his older sister, now aged two. Doctors feel confident that Umut’s sister will be cured with the cells from his discarded umbilical cord, and her monthly blood transfusions will be discontinued.
The family have since returned to their home in southern France, but they plan to return to Clamart to undergo the same procedure to cure their other child, Umut’s four-year-old brother.
Hopes and hurdles
French newspapers spread “medicine baby” across headlines on Tuesday. But speaking at a press conference René Frydman, a fertility pioneer and father of the first French test-tube baby, who also oversaw Umut’s case, said he preferred the term “double-hope baby”.
“Medicine baby is a media term invented by people who are against this kind of procedure,” Frydman told reporters. In English-speaking countries, the terms “donor baby” and “saviour sibling” have been widely used in the media.
For Frydman, Umut represents a double hope for his parents: the hope of having a new, healthy baby, and the hope of curing one of their sick children. But other scientists, religious groups and parents beg to differ.
The issue of saviour babies has raised complex ethical debates, and renewed fears of a move towards “designer babies”, or babies whose traits – such as intelligence, eye-colour and height – have been predetermined.
The timing of Umut's birth could be significant. The very law that allows for cases like Umut’s is being revised starting today. Observers say that the existing legislation guiding biotechnology in France may be tightened and restrict research in certain fields, including stem cells.
The country’s standing bioethics law allows for cases like Umut’s. In fact, the government has earmarked 800,000 euros per year for Clamart to practice and develop the procedure.
But Frydman and his colleagues say a lot more needs to be done, complaining of endless hurdles to launch further research and access funds. They regret that France has started a decade after the United States and that the government is still reluctant to give them its full backing.
2/10/11
Researchers report gene therapy strategy that improves Beta Thalassemia in mice model
Researchers at Nationwide Children's Hospital report a gene therapy strategy that improves the condition of a mouse model of an inherited blood disorder, Beta Thalassemia. The gene correction involves using unfertilized eggs from afflicted mice to produce a batch of embryonic stem cell lines. Some of these stem cell lines do not inherit the disease gene and can thus be used for transplantation-based treatments of the same mice. Findings could hold promise for a new treatment strategy for autosomal dominant diseases like certain forms of Beta Thalassemia, tuberous sclerosis or Huntington's disease.
Embryonic stem cells have the potential to produce unlimited quantities of any cell type and are therefore being explored as a new therapeutic option for many diseases. Unfertilized eggs can be cultured to form embryonic stem cells, so-called parthenogenetic embryonic stem cells.
"Parthenogenetic embryonic stem cells can differentiate into multiple tissue types as do stem cells from fertilized embryos," said K. John McLaughlin, PhD, principal investigator in the Center for Molecular and Human Genetics at The Research Institute at Nationwide Children's Hospital. Previously, the group demonstrated that blood cells derived from parthenogenetic cells could provide healthy, long-term blood replacement in mice.
"Advantages of parthenogenetic stem cells are not only that fertilization is not needed, but also that the recipient's immune system may potentially not view them as foreign, minimizing rejection problems. Furthermore, since parthenogenetic embryonic stem cells are derived from reproductive cells which contain only a single set of the genetic information instead of the double set present in body cells, they may not contain certain abnormal genes present in the other copy," said Dr. McLaughlin also one of the study authors.
Embryonic stem cells have the potential to produce unlimited quantities of any cell type and are therefore being explored as a new therapeutic option for many diseases. Unfertilized eggs can be cultured to form embryonic stem cells, so-called parthenogenetic embryonic stem cells.
"Parthenogenetic embryonic stem cells can differentiate into multiple tissue types as do stem cells from fertilized embryos," said K. John McLaughlin, PhD, principal investigator in the Center for Molecular and Human Genetics at The Research Institute at Nationwide Children's Hospital. Previously, the group demonstrated that blood cells derived from parthenogenetic cells could provide healthy, long-term blood replacement in mice.
"Advantages of parthenogenetic stem cells are not only that fertilization is not needed, but also that the recipient's immune system may potentially not view them as foreign, minimizing rejection problems. Furthermore, since parthenogenetic embryonic stem cells are derived from reproductive cells which contain only a single set of the genetic information instead of the double set present in body cells, they may not contain certain abnormal genes present in the other copy," said Dr. McLaughlin also one of the study authors.
A single copy of an abnormal gene inherited from one parent can cause so-called autosomal dominant diseases such as tuberous sclerosis or Huntington's disease. The affected person has one defective and one normal copy of the gene, but the abnormal gene overrides the normal gene, causing disease. In normal sexual reproduction, each parent provides one gene copy to offspring via their reproductive cells. Therefore, the reproductive cells of a patient with an autosomal dominant disease could either pass along a defective copy or a normal copy.
"As the donor patient has one defective gene copy and one normal, and only one copy is used for normal reproduction, we can select egg-cell-derived embryonic stem cells with two normal copies," said Dr. McLaughlin. "These single-parent/patient-derived embryonic stem cells can theoretically be used for correction of a diverse number of diseases that occur when one copy of the gene is abnormal," said Dr. McLaughlin.
To test this theory, Dr. McLaughlin and colleagues from the University of Pennsylvania, University of North Carolina and University of Minnesota, examined whether parthenogenetic embryonic stem cells could be used for tissue repair in a mouse model of thalassemia intermedia. Thalassemia intermedia is an inherited blood disorder in which the body lacks sufficient normal hemoglobin, leading to excessive destruction of red blood cells and anemia. They used a mouse model in which one defective gene copy causes anemia.
Using approaches developed from a previous study done by this group, Nationwide Children's Research Fellow Sigrid Eckardt, PhD, derived embryonic stem cells from the unfertilized eggs of female mice with the disease, and identified those stem cell lines that contained only the "healthy" hemoglobin genes. These "genetically clean" embryonic stem cell lines were converted into cells that were transplanted into afflicted mice that were carriers of the disease causing gene. Blood samples drawn five weeks after transplantation revealed that the delivered cells were present in the recipients' blood. Their red blood cells were also corrected to a size similar to normal mice and red blood cell count, hematocrit and hemoglobin levels became normal.
"Overall, we observed long-term improvement of thalassemia in this model," said Dr. Eckardt. "Our findings suggest that using reproductive cells to generate embryonic stem cells that are 'disease-free' may be a solution for genetic diseases involving large, complex or poorly identified deletions in the genome or that are not treatable by current gene therapy approaches." Dr. McLaughlin says that this approach also contrasts with typical gene therapy approaches in that it requires no engineering of the genome, which is currently difficult to achieve in human embryonic and embryonic-like (IPS) stem cells.
Source: Nationwide Children's Hospital
"As the donor patient has one defective gene copy and one normal, and only one copy is used for normal reproduction, we can select egg-cell-derived embryonic stem cells with two normal copies," said Dr. McLaughlin. "These single-parent/patient-derived embryonic stem cells can theoretically be used for correction of a diverse number of diseases that occur when one copy of the gene is abnormal," said Dr. McLaughlin.
To test this theory, Dr. McLaughlin and colleagues from the University of Pennsylvania, University of North Carolina and University of Minnesota, examined whether parthenogenetic embryonic stem cells could be used for tissue repair in a mouse model of thalassemia intermedia. Thalassemia intermedia is an inherited blood disorder in which the body lacks sufficient normal hemoglobin, leading to excessive destruction of red blood cells and anemia. They used a mouse model in which one defective gene copy causes anemia.
Using approaches developed from a previous study done by this group, Nationwide Children's Research Fellow Sigrid Eckardt, PhD, derived embryonic stem cells from the unfertilized eggs of female mice with the disease, and identified those stem cell lines that contained only the "healthy" hemoglobin genes. These "genetically clean" embryonic stem cell lines were converted into cells that were transplanted into afflicted mice that were carriers of the disease causing gene. Blood samples drawn five weeks after transplantation revealed that the delivered cells were present in the recipients' blood. Their red blood cells were also corrected to a size similar to normal mice and red blood cell count, hematocrit and hemoglobin levels became normal.
"Overall, we observed long-term improvement of thalassemia in this model," said Dr. Eckardt. "Our findings suggest that using reproductive cells to generate embryonic stem cells that are 'disease-free' may be a solution for genetic diseases involving large, complex or poorly identified deletions in the genome or that are not treatable by current gene therapy approaches." Dr. McLaughlin says that this approach also contrasts with typical gene therapy approaches in that it requires no engineering of the genome, which is currently difficult to achieve in human embryonic and embryonic-like (IPS) stem cells.
Source: Nationwide Children's Hospital
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