Have you heard about induced pluripotent stem cells (iPS cells), but don’t know exactly what they are and what they can do? If so, read on to learn the answers to frequently asked questions (FAQs) about iPS cells.
In this article:
- What Are iPS Cells?
- How Are iPS Stem Cells Produced?
- What Are the Advantages of iPS Cells Over ES Cells?
- Are iPS Cells Similar to Embryonic Stem Cells?
- What Are the Risks of iPS Cell Use?
- What Are the Challenges in iPS Cell Research?
- Do iPS Cells Have the Potential for Medical Applications?
A Closer Look at iPS Cells
Induced pluripotent stem cells (iPS cells) are differentiated cells that are reprogrammed back into an embryonic-like state. Derived from skin or blood cells, iPS cells are not controversial, because they are made from adult cells. As pluripotent stem cells, they can give rise to nearly all of the tissues that form the human body.
What Are iPS Cells?
Induced pluripotent stem cells (iPS cells or iPSCs) are commonly derived from blood or skin cells that have been reprocessed back to an embryonic-like state. This allows for the development of various human cell types for therapeutic uses.
For example, an iPS cell can be prodded to become a beta islet cell and then used in the treatment of diabetic patients. They can also be stimulated into blood cells for leukemia therapy, or neurons to treat neurological disorders.
How Are iPS Stem Cells Produced?
iPS cells can be made in several ways depending on its type. One method is genetic reprogramming. Some labs use a handful of genes to reprogram a normal cell, like a skin cell, into an IPSC. Klf4, Myc, Sox2, and Oct4 are genes commonly introduced into a cell using viruses.
Embryonic stem cells (ES cells) are a type of pluripotent stem cell that is similar to iPS cells, but different because they are collected from an early stage embryo, called a blastocyst. Similar to iPS cells, ES cells are processed in a lab to let them develop into ES cell lines. This approach is usually for research purposes, because it helps researchers understand how stem cells differentiate and behave.
What Are the Advantages of iPS Cells Over Embryonic Stem Cells?
One advantage of iPS cells is that they can be created without requiring human embryos, which carry ethical issues and controversy. Another benefit is that iPS stem cells allow the creation of isogenic control cell lines through CRISPR/Cas9 gene editing. This gene editing permits the changing of DNA to treat human diseases using cells.
Are iPS Cells Similar to Embryonic Stem Cells?
Yes, iPSCs are similar to embryonic stem cells (ES cells) in many ways, such as proliferation, morphology, expression of pluripotency markers, and teratoma formation. PSCs also express genes and stem cell surface markers that distinguish ES cells, like TRA-1-81, TRA-1-60, Sox2, and Oct4.
What Risks are Associated with iPS Cell Use?
There are a few risks associated with using iPSC-derived cell types in human patients. These include:
- Risk of cancer formation: iPSCs have the capacity to form benign tumors, called teratomas, or lead to malignant growth if they are not properly controlled.
- Oncogene use in reprogramming: Some methods for creating iPSCs involve the use of oncogenes, such as c-Myc, which could increase the risk of tumor formation if not managed properly. In some cases, its overexpression can trigger cancerous growth.
- Mutations during reprogramming: The process of reprogramming somatic (normal adult) cells into iPSCs has the potential to induce genetic mutations.
- Epigenetic memory: iPSCs sometimes retain epigenetic marks from their tissue of origin, which could affect their behavior or differentiation potential.
In addition, regulators are still debating how to regulate these novel cellular therapeutics.
For this reason, although there are now at least 69 different companies worldwide who are involved with the development of iPSC-derived cellular therapeutic, no iPSC-derived cellular therapeutic has yet to receive approval from the U.S. FDA or any other major regulatory body worldwide.
What Are the Challenges Facing iPS Cell Research?
One challenge in research about iPS cells is that the change in DNA creates a forced expression of the genes. This situation cannot be controlled completely, leading to unpredictable effects. In terms of clinical application, these cells require an efficient and safe generation of stem cells to achieve the full effectiveness of the reprogramming process.
Researchers are still in the phase of understanding these cells’ molecular mechanisms relating to reprogramming. This means there is no definite time as to when iPSC technology can be effective for widespread use.
Do iPS Cells Have the Potential for Medical Applications?
iPSCs definitely have the potential for medical applications. They can be used for regenerative medicine support, screening and developing new drugs, and understanding different types of diseases. For example, in creating new drugs, researchers can use cultured stem cells to test drugs and help them understand its therapeutic possibilities.
Immune rejection is also minimized because the stem cell sample is taken from the patients themselves. This reason alone creates a promising window for iPSC to contribute to advancements in therapeutic medicine.
iPS cells, just like other types of stem cells, promise a brighter future for regenerative medicine. They can be modified into a cell type to match the therapeutic need of the disease being treated. It is still important to consider, however, that continued research is needed to understand the behavior and mechanisms of iPS stem cells so that they can become safe for widespread use.
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