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New technique isolates blood-forming stem cells
Issue date: 4/17/08
With this problem in mind, Sharkis developed a new approach to isolating HSC using centrifugation and a strategy known as homing, where the stem cells are drawn to a location in the living organism.
The crucial step in the protocol involves removing the animal's bone marrow, the location where most of the HSC reside.
The bone marrow is then separated by centrifugation, or high-speed spinning. This separates the cells based on their density.
Taking the cells at the correct density, they then undergo a process known as lineage depletion. This step separates the HSCs from mature cells, such as red blood cells.
After lineage depletion, this population of cells is stained with a fluorescent dye. The stained cells are then injected into immunocompromised mice, which have immune systems that will not attack the injected cells.
From here, the HSCs "home" to their niche, which is located in the bone marrow. The niche is a protective compartment that regulates stem cells.
After two days of growth in the mice, the bone marrows are flushed once again and the HSCs are isolated using FACS, which sorts cells based on certain characteristic fluorescence.
The cells that are positive for the fluorescent dye are isolated and these are the HSCs which can then be used for scientific research.
This method of FACS is different from previous methods of FACS because it stains the nuclei of the cells and tracks them based on the nuclear stain, not a cell surface-marker stain.
Not only will this method decrease the variability associated with previous isolation methods, it also uses the innate system of the donor mouse to culture and expand the cells.
The novel method created by the researchers will prove invaluable as research into hematopoietic stem cell biology continues.
This method may also be applied to stem cells in other compartments, although it has not yet been tested in these other tissues or organs.
With the promise of stem cell-based therapies, it is imperative to create standardized methods, which isolate stem cells based on their quiescent, or non-dividing, state.
If this is done, medical therapies will be one step closer to reality for patient with life-threatening diseases.
The crucial step in the protocol involves removing the animal's bone marrow, the location where most of the HSC reside.
The bone marrow is then separated by centrifugation, or high-speed spinning. This separates the cells based on their density.
Taking the cells at the correct density, they then undergo a process known as lineage depletion. This step separates the HSCs from mature cells, such as red blood cells.
After lineage depletion, this population of cells is stained with a fluorescent dye. The stained cells are then injected into immunocompromised mice, which have immune systems that will not attack the injected cells.
From here, the HSCs "home" to their niche, which is located in the bone marrow. The niche is a protective compartment that regulates stem cells.
After two days of growth in the mice, the bone marrows are flushed once again and the HSCs are isolated using FACS, which sorts cells based on certain characteristic fluorescence.
The cells that are positive for the fluorescent dye are isolated and these are the HSCs which can then be used for scientific research.
This method of FACS is different from previous methods of FACS because it stains the nuclei of the cells and tracks them based on the nuclear stain, not a cell surface-marker stain.
Not only will this method decrease the variability associated with previous isolation methods, it also uses the innate system of the donor mouse to culture and expand the cells.
The novel method created by the researchers will prove invaluable as research into hematopoietic stem cell biology continues.
This method may also be applied to stem cells in other compartments, although it has not yet been tested in these other tissues or organs.
With the promise of stem cell-based therapies, it is imperative to create standardized methods, which isolate stem cells based on their quiescent, or non-dividing, state.
If this is done, medical therapies will be one step closer to reality for patient with life-threatening diseases.
Viewing Comments 1 - 1 of 1
don margolis
posted 4/19/08 @ 5:13 PM EST
This article is unique in one respect and common in another.
The common aspect is that the word ADULT stem cell (ASC) is never used, which is the rule in America when discussing a positive result of ASC research--NEVER OPENLY DISCUSS A POSITIVE RESULT OF ASC RESEARCH unless you can cover up the fact that it is ASC, since it might hurt the politically correct (but fraudulent) science fiction of embryonics. (Continued…)
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