Tag Archives: University of California San Francisco

Growing new brain cells for implants

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The dream is that one day this research will allow doctors to replace damaged or destroyed brain cells. According to the May 7, 2013 news release on EurekAlert,

A key type of human brain cell developed in the laboratory grows seamlessly when transplanted into the brains of mice, UC [University of California] San Francisco researchers have discovered, raising hope that these cells might one day be used to treat people with Parkinson’s disease, epilepsy, and possibly even Alzheimer’s disease, as well as and complications of spinal cord injury such as chronic pain and spasticity.

“We think this one type of cell may be useful in treating several types of neurodevelopmental and neurodegenerative disorders in a targeted way,” said Arnold Kriegstein, MD, PhD, director of the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at UCSF [University of California San Francisco] and co-lead author on the paper.

The May 7, 2013 University of California San Francisco news release by Jeffrey Norris, which originated the release on EurekAlert, provides more detail about the work,

The researchers generated and transplanted a type of human nerve-cell progenitor called the medial ganglionic eminence (MGE) cell, in experiments described in the May 2 edition of Cell Stem Cell. Development of these human MGE cells within the mouse brain mimics what occurs in human development, they said.

…

To generate MGE cells in the lab, the researchers reliably directed the differentiation of human pluripotent stem cells — either human embryonic stem cells or induced pluripotent stem cells derived from human skin. These two kinds of stem cells have virtually unlimited potential to become any human cell type. When transplanted into a strain of mice that does not reject human tissue, the human MGE-like cells survived within the rodent forebrain, integrated into the brain by forming connections with rodent nerve cells, and matured into specialized subtypes of interneurons

The researchers are investigating applications other than brain cell replacement or repair (from the UCSF news release),

Previously, UCSF researchers led by Allan Basbaum, PhD, chair of anatomy at UCSF, have used mouse MGE cell transplantation into the mouse spinal cord to reduce neuropathic pain, a surprising application outside the brain. Kriegstein, Nicholas and colleagues now are exploring the use of human MGE cells in mouse models of neuropathic pain and spasticity, Parkinson’s disease and epilepsy.

“The hope is that we can deliver these cells to various places within the nervous system that have been overactive and that they will functionally integrate and provide regulated inhibition,” Nicholas said.

The researchers also plan to develop MGE cells from induced pluripotent stem cells derived from skin cells of individuals with autism, epilepsy, schizophrenia and Alzheimer’s disease, in order to investigate how the development and function of interneurons might become abnormal — creating a lab-dish model of disease.

There is at least one hurdle to be overcome (from the UCSF news release),

One mystery and challenge to both the clinical and pre-clinical study of human MGE cells is that they develop at a slower, human pace, reflecting an “intrinsic clock”. In fast-developing mice, the human MGE-like cells still took seven to nine months to form interneuron subtypes that normally are present near birth.

“If we could accelerate the clock in human cells, then that would be very encouraging for various applications,” Kriegstein said.

Here’s a link to and a citation for the researchers’ paper,

Functional Maturation of hPSC-Derived Forebrain Interneurons Requires an Extended Timeline and Mimics Human Neural Development by Cory R. Nicholas, Jiadong Chen, Yunshuo Tang, Derek G. Southwell, Nadine Chalmers, Daniel Vogt, Christine M. Arnold, Ying-Jiun J. Chen, Edouard G. Stanley, Andrew G. Elefanty, Yoshiki Sasai, Arturo Alvarez-Buylla, John L.R. Rubenstein, Arnold R. Kriegstein. Cell Stem Cell, Volume 12, Issue 5, 573-586, 2 May 2013

Copyright © 2013 Elsevier Inc. All rights reserved.
10.1016/j.stem.2013.04.005

This research put in me in mind of my Mar. 15, 2013 posting titled, Growing a tooth—as an adult, when I featured research at King’s College London where scientists had successfully used mouse stem cells to  grow teeth in adult mice. The researchers hope to one day be able to do the same in humans.

The myth of Canada’s nanomaterials reporting plan

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The myth of Canada’s nanomaterials reporting plan/inventory lives on. A group (Program on Reproductive Health and Environment) at the University of California in San Francisco just issued a draft set of policy recommendations titled “A Nanotechnology Policy Framework: Policy Recommendations for Addressing Potential Health Risks from Nanomaterials in California.”  From the news item on Nanowerk,

This draft document addresses the new challenges that nanomaterials present to the policy and risk assessment process because of their unique properties. It draws upon lessons we can learn from past chemical policy experiences and other recent nanotechnology reports in making recommendations for California. There will be a public meeting to discuss the draft document and receive feedback from the Science Advisory Panel and the general public. All public comments must be received by May 5, 2010.

I took a look at the report and found this on page 19,

Canada recently moved to implement a new program that requires manufacturers of nanomaterials to provide physical, chemical and toxicity data about nanoproducts they make in more than one kilogram quantities. They will then use this data to create new risk assessments and further regulation.

Unfortunately, there is no such program currently being implemented in Canada but it is mentioned in reports from other jurisdictions such as this one from California and, if memory serves, the January 2010 House of Lords report on nanotechnologies and food. There is never a citation for this documented ‘fact’ and I suspect that this is due to the ‘information’ being copied from one report to the next without any authentification. (Frankly, I probably would have done the same had I been in that situation. You don’t have time to track down every single assertion in every document [from reputable sources] you review before preparing a report.)

I last posted about the reporting plan/inventory/scheme here as part of an introduction to questions to Health Canada about the proposed plan and also about a nanomaterials definition.