Researchers find key substance for brain cell regeneration

Taiwan’s National Health Research Institutes (NHRI) has cultivated a nano-scale substance from stem cells that can repair damaged brain nerves and could pave the way for the development of a cure for neurological and degenerative diseases.

Using its patented technique, a team of researchers led by Li Hua-jung (李華容), an assistant research fellow at the NHRI’s Institute of Cellular and System Medicine, extracted exosomes carrying a repairing signal from stem cells that exist in body fat and marrow tissue, she told CNA on Thursday.

Exosomes are small, 30-150 nm fluid-filled sacs known as vesicles that contain sophisticated RNA and protein cargoes and are present in many and perhaps all eukaryotic fluids, including blood, urine, and cultured cell mediums.

As a substance that enables communication between cells, stem cell-derived exosomes carry different signals under different circumstances, both healthy and pathological, Li said.

Li’s team spent five years trying to take advantage of that “communication” characteristic by developing exosomes with healing properties that can be injected into the body to serve as “first-aid kits” that repair damaged nerves, she said.

Unlike traditional stem cell therapies, exosomes are not living cells and therefore cannot develop into cancer cells after being injected into damaged parts of the body they are meant to repair, according to Li.

Thanks to their nano size and outer lipid layer, however, exosomes can easily circulate in the blood and pass through brain barriers to the damaged nerves of a patient suffering from dementia, for example, Li said.

In trials on mice, the research team found that one week after injecting the special exosomes into mice whose hippocampus was damaged, the damaged nerves began to grow synapses, structures that permit a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron.

The hippocampus is the part of the brain that plays a key role in forming new memories, and a shrinking hippocampus has been associated with Alzheimer’s.

In Li’s test mice, the number of functioning hippocampus neurons, which had fallen to 20 percent of the total when the hippocampus is healthy, rose to 60 percent of the norm within one month, she said.

While Harvard University and Oxford University have set up institutes dedicated to the research of stem cell-derived exosomes, “Taiwan is the first to have successfully cultivated the exosomes working to repair,” the researcher said.

The cultivation technique has been patented in Taiwan, and patents are now being applied for in the U.S., the U.K. and Japan.

Li said that while her team’s exosome research was currently limited to treating neurological diseases, it could also be applied in the future to therapies for degenerative diseases, organ damage, cell defection, injured brain and spine marrow, strokes, or learning disabilities.

The results of the study, which have yet to be published in any international journals, were unveiled at a bio-tech presentation held by the NHRI on Jan. 25 to pursue cooperation with the private sector in promoting the institute’s innovative biomedical technologies.

Li is in the process of writing a paper summarizing the team’s findings and is also hoping to find a partner for the technology so that further clinical trials can be conducted and a therapeutic drug developed.

Source – Focus Taiwan

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