Re: Researcher Regenerates Nerve Cells

[Guest guest]

Back in the 80's I used to do this research, CNS regeneration, using

a goldfish animal model. Goldfish have what we call

an " identifiable neuron " that we can easily stain and that has

specific behavior associated with it. We would teach the animal a

certain behavior, lesion those neurons (Mauthner cells for those

playing the home game) by cutting the spinal cord in a particular

place, and then manipulate various external and internal

environmental variables. Not only would we assess growth over the

lesion post-mortem, but we would also see if the growth was

FUNCTIONAL. Namely, we'd see if the animal would re-aquire its

previously learned behavior (C-reflex to a light/auditory paired

tone), something that couldn't happen if the neurons hadn't regrown

over the spinal lesion.

So, this is another great variable to manipulate. It will be very

interesting to see what happens when they assess this varible in

terms of its functional implications in an animal model.

> U Researcher Regenerates Nerve Cells

> By Matt Groesbeck

> Published: Wednesday, July 11, 2001

>

> Through genetic tinkering, Maureen Condic can regenerate

> nerve cells. This research may lead to improved treatments for

> spinal and brain injuries.A University of Utah neuroscientist has

> developed a way to spur adult nerve cells to regenerate, which

> may lead to new treatments for debilitating brain and spinal-cord

> injuries

> .

> Maureen Condic, researcher in the department of neurobiology

> and anatomy at the U School of Medicine, said her study had a

> different approach than other regeneration studies. Previous

> researchers in this field altered the nerves' environment,

> whereas Condic altered the properties of the nerve cells in an

> effort to regenerate nerves in the adult central nervous system.

> " We saw a huge improvement in the ability of adult neurons to

> extend their axons, " Condic said.

>

> An axon is the part of the nerve that transmits electrical signals

> down to other nerves or tissue, said Condic. She explained

> when the electrical signals are cut off, the nerve cells in the

brain

> and spinal cord, or central nervous system (CNS), don't

> regenerate to fix themselves.

>

> In contrast, peripheral nerves, those in other parts of the body,

> can regrow after they're severed, an important attribute that

> allows people with severed limbs the hope to regain motor and

> sensory function, as was the case with the Florida boy whose

> arm was reattached after a shark bit it off last weekend.

> " The inability of adult CNS neurons to regenerate is believed to

> be primarily attributable to the poor environment that the CNS

> provides for neuronal growth, " Condic said in report published in

> the July Journal of Neuroscience.

>

> Most neuronal regeneration studies have manipulated factors in

> the environment to try to influence neuron growth, Condic said.

> To get into the neuron, Condic used an inactivated virus as a

> vehicle to deliver the desired instructions. A virus is stripped

of

> its original genetic information, or " silenced, " and replaced with

> the desired cargo. Through the silenced virus, Condic introduced

> integrin into the nerve cell.

>

> Integrin is to a nerve what tires are to a car, Condic said.

> " It's as though you have a '57 Chevy on blocks in the front yard,

> and it has all the necessary components except for its wheels. If

> you give the wheels back, which are the car's usual way of

> interacting with the environment, it's ready to go, " Condic said.

> Condic believes increasing integrin levels can direct the neuron

> to grab onto extracellular objects to propel its growth. By

> increasing amounts of integrin, Condic increased the nerve-fiber

> growth 10 times more than that in any other published study.

> Regulating the amount of growth is the first challenge to

> Condics' results.

>

> " We don't want uncontrolled regeneration, " Condic said.

> However, Condic said it is possible to control when the gene

> goes on and off.

>

> " The next step is critical, " Condic said. " I'm optimistic that at

least

> some of this will hold up in a more realistic animal model of

> injury. "

>

> Michele Lemons, a neuroscience post-doctoral fellow with

> surgery expertise, and Condic's assistant, will continue Condic's

> integrin expression research as it expands from the petri dish to

> three dimensional animal models.

>

> Animal studies will start in a few months as soon as Lemons

> receives federal and local grants.

>

> " I think this is really a profound set of experiments that

[Condic]

> has done…the extent of regrowth is so phenomenal that it

> provides promise for future studies, " Lemons said.

> Lemons anticipates many obstacles in researching animal

> models, such as unknown environmental and anatomical

> problems, not to mention the challenge of moving from a 2-D

> petri dish to more complicated 3 D surgery.

>

> Ultimately, Lemons envisions that the most successful result, in

> terms of therapeutic benefits, may not be a single approach, but

> the combination of other therapies as well.

> " I think to get successful regeneration, it's going to be a

> multi-faceted approach that includes a variety of therapies, "

> Lemons said.

>

> Condic believes that future studies will prove worthwhile based

> on her initial findings. " This is all very theoretical, but it is

not

> imaginary, " Condic said. " This gives us a new tool, a new

> weapon in our arsenal, with ultimate therapeutic effects…even

> when I'm in my most cynical mode, I can see very few downsides

> to this approach. "

> According to Lemons, applicable results from Condic's lab won't

> be known for at least two years.

>

> mgroesbeck@c...