Stem Cells Not the Priority for Alzheimer's

Experts cite other more promising efforts that in five to 10 years may be used to fight the disease that led to President Reagan's death.

"I just think everybody feels there are higher priorities for seeking effective treatments for Alzheimer's disease and for identifying preventive strategies," said Marilyn Albert, a Johns Hopkins University researcher who chairs the Medical and Scientific Advisory Council of the Alzheimer's Association.

Stem cells from human embryos can form all types of cells, and the hope is that they one day could be used to replace cells damaged from such conditions as diabetes, spinal cord injury or Parkinson's disease. But experts say Alzheimer's, by the very nature of how it attacks the brain, would pose a far more daunting challenge to that approach.

"There's an awful lot going on right now that perhaps holds a little bit more immediate promise for trying to slow the disease, or even cut off its development," said Marcelle Morrison-Bogorad, associate director of the National Institute on Aging's neuroscience and neuropsychology-of-aging program.

She and Albert cited, for example, efforts to attack the buildup of clumps of protein called amyloid in the brain, and methods for spotting the disease early. That research will probably pay off in five or 10 years, earlier than any expected advances from stem cells, Albert said, because so much has to be learned about how to make stem cells useful against the disease.

"All the more reason we should start [stem cell efforts] now, because it's going to take a long time," she said.

About 4.5 million Americans have Alzheimer's, a progressive brain disorder that gradually destroys memory and ability to learn, reason, communicate and do everyday activities. Patients die on average eight years after symptoms appear, although the disease can linger for 20 years.

"What you're dealing with here is a mind in disarray," Morrison-Bogorad said. Connections between brain cells are being lost, neurons are dying and becoming dysfunctional, the amyloid plaques are building up between brain cells and protein tangles are showing up within cells. And there's inflammation.

"It's just a mess in there," she said. "But the mess means there are so many targets for intervention."

The amyloid plaques have emerged as a favorite target, and scientists and drug companies around the world are studying ways to prevent or destroy them.

One high-profile approach is a vaccine that primes the body to attack amyloid. Studies on animals were encouraging, but in 2002 a study on people was halted when several vaccine recipients developed brain inflammation. Last year, researchers reported that the vaccine did appear to reduce the accumulation of plaques in one study participant.

Work is continuing now on a safer vaccine, because the available evidence suggests "this is an important avenue to pursue," Albert said.

Another popular approach seeks to keep the brain from making the abnormal form of amyloid that creates the plaques. It's a high priority at "every major drug company," Albert said.

"Everybody's working on it," she said. "What we've learned from the past is that if everybody works really hard at something that is sensible, they're likely to make a lot of progress. So there's just enormous optimism that in five years, or certainly 10 years, we'll have much more effective treatments."

Another key research area is finding a way to predict who will get Alzheimer's before symptoms appear. Because the disease develops over many years, much damage has been done by the time it's diagnosed. So scientists want to identify people at an earlier stage for the day when more effective treatments become available.

In the same vein, scientists want to find ways to track the progress of the disease in people being treated, so they can quickly tell if the treatment is helping.

So researchers are doing long-term studies to see if different kinds of brain scans, mental tests and spinal or blood tests can predict development or progression of the disease.

Lifestyle factors too, such as taking anti-inflammatory drugs and vitamins like E and C, are being studied to see if they can help prevent Alzheimer's or delay it.

Researchers are also exploring the use of cholesterol-lowering drugs. A relatively recent idea, Albert said, is that things like keeping cholesterol and blood pressure low and staying physically active may help. Those steps are well-known for countering heart disease, she noted.

But it's becoming clearer, she said, that "if you do things that are good for your heart, they'll be good for your brain."

Carlton Fredericks talked about a link between Alzheimer's and aluminum about 30 yrs. ago and cautioned cooking in aluminum pots and using deodorant.

Hopefully progress is made quickly without the use of embryonic stem cells.>>>

Progress has already been made:

*In 2000, Israeli scientists implanted Melissa Holley's white blood cells into her spinal cord to treat the paraplegia caused when her spinal cord was severed in an auto accident. Melissa, who is 18, has since regained control over her bladder and recovered significant motor function in her limbs - she can now move her legs and toes, although she cannot yet walk.

This is exactly the kind of therapy that embryonic-stem-cell proponents promise - years down the road. Yet Melissa's breakthrough was met with collective yawns in the press with the exception of Canada's The Globe and Mail. Non-embryonic stem cells may be as common as beach sand.

They have been successfully extracted from umbilical cord blood, placentas, fat, cadaver brains, bone marrow, and tissues of the spleen, pancreas, and other organs. Even more astounding, the scientists who cloned Dolly the sheep successfully created cow heart tissue using stem cells from cow skin. And just this week, Singapore scientists announced that they have transformed bone-marrow cells into heart muscle.

Research with these cells also has a distinct moral advantage: It doesn't require the destruction of a human embryo. You don't have to be pro-life to be more comfortable with that.

*In another Parkinson's case, a patient treated with his own brain stem cells appears to have experienced a substantial remission with no adverse side effects. Dennis Turner was expected by this time to require a wheelchair and extensive medication. Instead, he has substantially reduced his medication and rarely reports any noticeable symptoms of his Parkinson's. Human trials in this technique are due to begin soon.

*Bone marrow stem cells, blood stem cells, and immature thigh muscle cells have been used to grow new heart tissue in both animal subjects and human patients. Indeed, while it was once scientific dogma that damaged heart muscle could not regenerate, it now appears that cells taken from a patient's own body may be able to restore cardiac function. Human trials using adult stem cells have commenced in Europe and other nations. (The FDA is requiring American researchers to stick with animal studies for now to test the safety of the adult stem cell approach.)

*Harvard Medical School researchers reversed juvenile onset diabetes (type-1) in mice using "precursor cells" taken from spleens of healthy mice and injecting them into diabetic animals. The cells transformed into pancreatic islet cells. The technique will begin human trials as soon as sufficient funding is made available.

*In the United States and Canada, more than 250 human patients with type-1 diabetes were treated with pancreatic tissue (islet) transplantations taken from human cadavers. Eighty percent of those who completed the treatment protocol have achieved insulin independence for over a year. (Good results have been previously achieved with pancreas transplantation, but the new approach may be much safer than a whole organ transplant.)

*Blindness is one symptom of diabetes. Now, human umbilical cord blood stem cells have been injected into the eyes of mice and led to the growth of new human blood vessels. Researchers hope that the technique will eventually provide an efficacious treatment for diabetes-related blindness. Scientists also are experimenting with using cord blood stem cells to inhibit the growth of blood vessels in cancer, which could potentially lead to a viable treatment.

*Bone marrow stem cells have partially helped regenerate muscle tissue in mice with muscular dystrophy. Much more research is needed before final conclusions can be drawn and human studies commenced. But it now appears that adult stem cells may well provide future treatments for neuromuscular diseases.

*Severed spinal cords in rats were regenerated using gene therapy to prevent the growth of scar tissue that inhibits nerve regeneration. The rats recovered the ability to walk within weeks of receiving the treatments. The next step will be to try the technique with monkeys. If that succeeds, human trials would follow.

*In one case reported from Japan, an advanced pancreatic cancer patient injected with bone marrow stem cells experienced an 80 percent reduction in tumor size.

* In separate experiments, scientists researched the ability of embryonic and adult mouse pancreatic stem cells to regenerate the body's ability to make insulin. Both types of cells boosted insulin production in diabetic mice. The embryonic success made a big splash with prominent coverage in all major media outlets. Yet the same media organs were strangely silent about the research involving adult cells.

Stranger still, the adult-cell experiment was far more successful - it raised insulin levels much more. Indeed, those diabetic mice lived, while the mice treated with embryonic cells all died. Why did the media celebrate the less successful experiment and ignore the more successful one?

* Another barely reported story is that alternative-source stem cells are already healing human illnesses.

*In Los Angeles, the transplantation of stem cells harvested from umbilical-cord blood has saved the lives of three young boys born with defective immune systems.

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