Use of Human Embryonic Stem Cells As Models For Human Genetic Disorders
Several new studies have started to address this issue. This has been done either by genetically manipulating the cells, or more recently by deriving diseased cell lines identified by prenatal genetic diagnosis (PGD). This approach may very well prove invaluable at studying disorders such as Fragile-X syndrome, Cystic fibrosis, and other genetic maladies that have no reliable model system.
Yury Verlinsky (Sept, 1, 1943 – July 16, 2009), a Russian-American medical researcher who specialized in embryo and cellular genetics (genetic cytology), developed prenatal diagnosis testing methods to determine genetic and chromosomal disorders a month and a half earlier than standard amniocentesis. The techniques are now used by many pregnant women and prospective parents, especially those couples with a history of genetic abnormalities or where the woman is over the age of 35, when the risk of genetically-related disorders is higher. In addition, by allowing parents to select an embryo without genetic disorders, they have the potential of saving the lives of siblings that already had similar disorders and diseases using cells from the disease free offspring.
Scientists have discovered a new technique for deriving human embryonic stem cell (ESC). Normal ESC lines from different sources of embryonic material including morula and whole blastocysts have been established. These findings allows researchers to construct ESC lines from embryos that acquire different genetic abnormalities; therefore, allowing for recognition of mechanisms in the molecular level that are possibly blocked that could impede the disease progression. The ESC lines originating from embryos with genetic and chromosomal abnormalities provide the data necessary to understand the pathways of genetic defects.
A donor patient acquires one defective gene copy and one normal, and only one of these two copies is used for reproduction. By selecting egg cell derived from embryonic stem cells that have two normal copies, researchers can find variety of treatments for various diseases. To test this theory Dr. McLaughlin and several of his colleagues looked at whether parthenogenetic embryonic stem cells can be used in a mouse model that has thalassemia intermedia. This disease is described as an inherited blood disorder in which there is a lack of hemoglobin leading to anemia. The mouse model used, had one defective gene copy. Embryonic stem cells from an unfertilized egg of the diseased mice were gathered and those stem cells that contained only healthy hemoglobin genes were identified. The healthy embryonic stem cell lines were then converted into cells transplanted into the carrier mice. After five weeks, the test results from the transplant illustrated that these carrier mice now had a normal blood cell count and hemoglobin levels. Nationwide Children's Hospital (2011, February 13). Embryonic stem cells help deliver 'good genes' in a model of inherited blood disorder.
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