Thursday, 7 February 2013

Scientists announce new iPSCs-based treatment for myelin disorders

Researchers from the Rochester Medical Centre (URMC) released a new study today where they exhibit, for the first time, that neural stem cells derived from human induced pluripotent stem cells (hiPSCs) may hold the key for treating one day myelin-related conditions, like multiple sclerosis and various rare paediatric leukodystrophies.

In this animal study the researchers, led by Steven Goldman, were successful in creating myelin-producing cells. As aforementioned, the cells were created from an hiPSC line which in turn was derived from human skin cells. Goldman said that their study not only suggests that an hiPSC based treatment would be effective for myelin disorders but it also indicates that cells derived from iPSCs seem to be more effective then the ones derived from embryonic stem cells.

According to the researchers, the study has great implications in the field of treating neurological conditions resulting from myelin loss. Myelin is an insulating material which forms a layer called the myelin sheath, which in turn plays an important role in the proper function of the central nervous system. Some indicative examples of such conditions are multiple sclerosis and a few extremely rare pediatric and commonly fatal conditions called pediatric leukodystrophies.

Myelin is produced by oligodendrocytes, a type of cell derived from neural stem cells (NSCs). It has long been hypothesised that myelin-related conditions may be treatable with therapies that would introduce a "fresh" population of healthy neural stem cells that in turn would differentiate into oligodendrocytes regenerating the lost myelin.


Picture of an Oligodendrocyte cell
An oligodendrocyte

Although it sounds easy, researchers face many problems in the development of such a treatment . The first one is that the neural stem cells from which oligodendrocytes are derived from, are cells that appear later in development, unlike neurons which are among the first cells to be formed during embryogenesis. Goldman, referring to NSCs-development explains:

"This process requires that we understand the basic biology and the normal development of these cells and then reproduce this precise sequence in the lab."

Then comes the second problem, finding a proper source to derive NSCs from. Previous literature suggests that embryonic stem cells are a very good candidate but they come with the risk of being rejected by the recipient's immune system.

The answer to this problem are induced pluripotent stem cells which are created by the patient's own tissue (e.g. skin). Due to their autologous nature, rejection-risks are minimal, and due to their pluripotent nature they have the potential to transform into all kinds of cells including NSCs. But still, there is the problem of finding the proper method to induce iPSCs into becoming NSCs.

In this study and after four years of hard work, the URMC researchers became the first to successfully create NSCs from a human iPSCs line. According to the study, each preparation to create sufficient amounts of NSCs from iPSCs was very time-consuming, requiring almost six months. After creating sufficient amounts of cells, the researchers moved to the next step, experimenting on a hereditary leukodystrophy mice model to test how efficient the cells were in the development of new myelin. Due to their condition, the mice were unable to produce any myelin and were the perfect candidate for testing the new neural stem cells.

The neural stem cells quickly spread throughout the brain and started producing new oligodendrocytes which in turn started to produce myelin. Additionally, during the 9-month follow up, no tumour-activity was reported, which is sometimes an adverse effect occuring in experimental stem cells treatments.

Goldman says that the new oligodendrocyte population was "dense, abundant and complete", and the study indicated that the re-myelination process  was more efficient and rapid compared to other mice groups that were treated with embryonic stem cell-derived NSCs. He now plans to start a clinical trial, involving the same method, on patients with multiple sclerosis, sometime during 2015.

References
Wang, S., Bates, J., Li, X., Schanz, S., Chandler-Militello, D., Levine, C., Maherali, N., Studer, L., Hochedlinger, K., Windrem, M., & Goldman, S. (2013). Human iPSC-Derived Oligodendrocyte Progenitor Cells Can Myelinate and Rescue a Mouse Model of Congenital Hypomyelination Cell Stem Cell, 12 (2), 252-264 DOI: 10.1016/j.stem.2012.12.002

3 comments:

  1. Melissa Tatum19 March 2013 00:22

    this sounds like hope for MS patients like myself. I hope that the human research is successful.

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  2. I agree with you, Melissa, let's get going with this-ALL of us with MS Want OUR LIVES BACK--!!

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  3. We appreciate all efforts towars helping people that can benefit from this research. Hope this gets positive results. Keep pushing, change parameters whatever, theres got to be a way.... Best wishes!

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