Wednesday, May 29, 2013

Saturday, May 11, 2013

Stem cell transplant restores memory, learning in mice

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By David Tenenbaum • ProHealth.com • May 11, 2013

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Reprinted with kind permission of University of Wisconsin-Madison News

By David Tenenbaum

Apr. 21, 2013 — For the first time, human embryonic stem cells have been transformed into nerve cells that helped mice regain the ability to learn and remember.

A study at the University of Wisconsin-Madison is the first to show that human stem cells can successfully implant themselves in the brain and then heal neurological deficits, says senior author Su-Chun Zhang, a professor of neuroscience and neurology.

Once inside the mouse brain, the implanted stem cells formed two common, vital types of neurons, which communicate with the chemicals GABA or acetylcholine. "These two neuron types are involved in many kinds of human behavior, emotions, learning, memory, addiction and many other psychiatric issues," says Zhang.

The human embryonic stem cells were cultured in the lab, using chemicals that are known to promote development into nerve cells -- a field that Zhang has helped pioneer for 15 years. The mice were a special strain that do not reject transplants from other species.

After the transplant, the mice scored significantly better on common tests of learning and memory in mice. For example, they were more adept in the water maze test, which challenged them to remember the location of a hidden platform in a pool.

The study began with deliberate damage to a part of the brain that is involved in learning and memory.

Three measures were critical to success, says Zhang: location, timing and purity. "Developing brain cells get their signals from the tissue that they reside in, and the location in the brain we chose directed these cells to form both GABA and cholinergic neurons."

The initial destruction was in an area called the medial septum, which connects to the hippocampus by GABA and cholinergic neurons. "This circuitry is fundamental to our ability to learn and remember," says Zhang.

The transplanted cells, however, were placed in the hippocampus -- a vital memory center -- at the other end of those memory circuits. After the transferred cells were implanted, in response to chemical directions from the brain, they started to specialize and connect to the appropriate cells in the hippocampus.

The process is akin to removing a section of telephone cable, Zhang says. If you can find the correct route, you could wire the replacement from either end.

For the study, published in the current issue of Nature Biotechnology, Zhang and first author Yan Liu, a postdoctoral associate at the Waisman Center on campus, chemically directed the human embryonic stem cells to begin differentiation into neural cells, and then injected those intermediate cells. Ushering the cells through partial specialization prevented the formation of unwanted cell types in the mice.

Ensuring that nearly all of the transplanted cells became neural cells was critical, Zhang says. "That means you are able to predict what the progeny will be, and for any future use in therapy, you reduce the chance of injecting stem cells that could form tumors. In many other transplant experiments, injecting early progenitor cells resulted in masses of cells -- tumors. This didn't happen in our case because the transplanted cells are pure and committed to a particular fate so that they do not generate anything else. We need to be sure we do not inject the seeds of cancer."

Brain repair through cell replacement is a Holy Grail of stem cell transplant, and the two cell types are both critical to brain function, Zhang says. "Cholinergic neurons are involved in Alzheimer's and Down syndrome, but GABA neurons are involved in many additional disorders, including schizophrenia, epilepsy, depression and addiction."

Though tantalizing, stem-cell therapy is unlikely to be the immediate benefit. Zhang notes that "for many psychiatric disorders, you don't know which part of the brain has gone wrong." The new study, he says, is more likely to see immediate application in creating models for drug screening and discovery.

Reference:

Yan Liu, Jason P Weick, Huisheng Liu, Robert Krencik, Xiaoqing Zhang, Lixiang Ma, Guo-min Zhou, Melvin Ayala, Su-Chun Zhang. Medial ganglionic eminence–like cells derived from human embryonic stem cells correct learning and memory deficits. Nature Biotechnology, 2013; DOI: 10.1038/nbt.2565

Thursday, May 9, 2013

Jilin student makes his second stem cell donation to ailing man

Updated: 2013-05-09 08:06

By Ou Hailin in Beijing and Han Junhong in Changchun (China Daily)

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Jilin student makes his second stem cell donation to ailing man

Wang Yuanxiang in Changchun, Jilin province, donates blood stem cells for a 37-year-old leukemia patient on Monday. Wang, a 24-year-old student at the Jilin Institute of Physical Education, has been a regular blood donor for six years. Sheng Xuesong / for China Daily

Wang Yuanxiang donated his blood stem cells for a leukemia patient about 1,000 km away on Monday.

It is his second donation in three years to the same patient.

Wang, a 24-year-old college student at Jilin Institute of Physical Education in Northeast China's Jilin province, has been a regular blood donor for six years.

Encouraged by a cousin who is a doctor, Wang had made a habit of donating blood once every six months.

It was his donations of blood that has led to Wang's contact with the China Marrow Donor Program and later his donation of the life-giving cells.

"I was on a blood collection bus when a nurse asked me whether I want to be a marrow donor," Wang said.

"It was 2009, and I had seen basketball star Yao Ming being a marrow donor on TV. I signed up for the program because I believe either donation could help someone."

Two years later, Wang was told he was a match for a man dying of leukemia.

"When I informed (Wang) and asked whether he still wanted to donate, he said, 'I keep my word,' " said Yu Li, a staff member at the Jilin branch of the China Marrow Donor Program, which is under the Red Cross Society of China.

Yu had also asked the young man, then a 22-year-old junior, to inform his family and university about his donation. It was while school was in session, and once the matching process started, the recipient will shoulder all the costs involved, which could be massive and yet in vain if the donor gives up halfway through the process.

But Wang did not tell anyone, a strategy he abandoned for his second donation.

It took him 10 days away from school to complete the donation process, which included the physical examination, hospital admission and the collection of the stem cells.

When he returned from the hospital, however, Wang was nearly punished by the school for his absence from class, until a thank-you letter from the recipient came to his rescue and helped him explain everything.

This March, Wang was told that the patient who had received his blood stem cells needed a second marrow transplant, and he was the only match that the CMDP could find.

Like the first time, Wang did not hesitate to say yes.

"I told my family and my doctor cousin about the donation. At first they didn't agree. But I insisted that if I did not donate this time, then my first donation would be meaningless," Wang said.

"And I told them, 'I am a man now who can take the responsibility for what I have done,' " he said. He finally persuaded his family to allow his second donation.

The process of his second donation on Monday was shorter than the first, since first-time donors have to take a drug for six days to stimulate the formation of new blood cells.

"You don't have to be anesthetized," Wang referring to the collection of the stem cells from the blood.

"The doctor hooks you up to a machine that extracts the stem cells from your blood and returns all the rest of your blood to your body.

"The only thing that troubled me was that I had to stay in the same position for three hours," Wang said.

Contact the writers at ouhailin@chinadaily.com.cn and hanjunhong@chinadaily.com.cn

(China Daily 05/09/2013 page4)

Tuesday, May 7, 2013

Stem cell research provides hope for epilepsy cure

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By Kent Mao

May 6, 2013 - 21 hours ago in Health

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Researchers from UC San Francisco have discovered a way to reverse severe forms of epilepsy in mice with stem cells, providing a new sense of hope for patients who suffer from the seizure-inducing disorder.

Published earlier this month in Nature Neuroscience, the UCSF study demonstrated that transplantation of medial ganglionic eminence (MGE) cells, embryonic neurons that can inhibit overactive brain signaling, was able to stop seizures in half of the epileptic mice that were treated.

The mice also appeared less agitated and hyperactive and seemed to perform better on learning and memory tests.

MGE cells were transplanted into a specific region of the brain known as the hippocampus, which is believed to play a part in seizures as well as learning and memory.

Previous studies show that transplanted MGE cells are capable of differentiating into a variety of mature neurons, including inhibitory GABA-ergic neurons. GABA-ergic neurons are known to suppress seizures when activated and abnormal GABA-ergic activity has been linked to animal models of epilepsy.

Cell transplants have become a recent focus in epilepsy research due to a lack of effective treatments, according to Scott C. Baraban, PhD, who led the UCSF study.

Baraban says that current drugs are focused on treating symptoms as opposed to the cause and fail to provide therapeutic benefit in many forms of epilepsy.

"Our results are an encouraging step toward using inhibitory neurons for cell transplantation in adults with severe forms of epilepsy," states Baraban. "This procedure offers the possibility of controlling seizures and rescuing cognitive deficits in these patients."

Still, the use of embryonic stem cells remains controversial and is significantly more invasive than conventional epilepsy treatments, which largely depend on the use of anticonvulsant medications.

Further research is required to confirm the therapeutic value of stem cells in human epilepsy, but the UCSF team remain encouraged by their discovery.

“This is the first report in a mouse model of adult epilepsy in which mice that already were having seizures stopped having seizures after treatment,” says Baraban.

Sunday, May 5, 2013

Stem cells may help Mumbai acid attack victim regain vision: doctors

Priyanka Vora , Hindustan Times Mumbai, May 05, 2013

First Published: 16:15 IST(5/5/2013) | Last Updated: 16:16 IST(5/5/2013)

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Ophthalmologists are hoping that Preeti Rathi, 25, who lost vision in her right eye after an unknown man threw acid on her face at Bandra Terminus, may be able to regain her vision after undergoing stem cell therapy.

On Saturday morning, Rathi, who was admitted inside the burns intensive care unit at Masina Hospital at Byculla, scribbled a note pleading her ophthalmologist Dr Yasmin Bhagat to help her see with both eyes again.

“We have helped patients of acid attack to regain vision by using stem cell therapy in the past. Once she (Rathi) recovers fully we can look at harvesting stem cells from her parents’ eye and transplanting them in her right eye as the cornea is damaged by the acid,” said Dr Bhagat.

Doctors said that her condition is stable and she was put on ventilator support for a few hours to give her rest. According to doctors, Rathi’s face is fully bandaged while her eyes are stil shut. “She cannot see but her left eye is showing improvement.” added Bhagat who has treated numerous such acid attack victims in the past.

Rathi’s father Amarsingh is planning to meet officials from INHS Asvini, where Preeti was supposed join as a nurse, to postpone her joining date. “If they postpone her joining, she would be very happy,” said Amarsingh

Meanwhile, The Bandra Government Railway Police (GRP), who are probing the acid attack, have scanned the passenger list of train in which the accused was travelling. Further probe is underway.

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