Navigation Links
Study Puts 1 Alzheimer's Theory in Doubt

Results in mice suggest a key gene might not be to blame, researchers say

MONDAY, Aug. 20 (HealthDay News) -- Research with mice is poking holes in a prevailing theory on the origins of Alzheimer's, scientists say.

Mice without a gene thought to rein in cell-damaging free radicals actually had fewer Alzheimer's-linked brain plaques than mice with the gene.

"This finding may go beyond Alzheimer's into all aging theory," noted lead researcher Carlos T. Moraes, an associate professor of neurology and cell biology and anatomy at the University of Miami Miller School of Medicine.

The study is published in this week's early edition of the journal Proceedings of the National Academy of Sciences.

Moraes said that, right now, "nobody knows what causes Alzheimer's disease," which affects more than 4.5 million Americans according to the National Institutes of Health.

However, one leading hypothesis is that there is a defect in the mitochondrial energy production system in cells, Moraes explained. The mitochondria are the cell's "power houses," giving it the energy it needs to function.

In prior studies, examination of the brain cells of people with Alzheimer's found some defects in an enzyme produced by the cytochrome c oxidase (COX) gene, which is important for mitochondrial energy production.

In addition, so-called "free radicals," which cause oxidative stress, are produced in the cell's mitochondria, Moraes noted. "It was assumed that when you have a problem with the COX gene, you have more free radicals being formed," he said.

To see how the gene worked, Moraes's group removed the COX10 gene in mice engineered to develop Alzheimer's disease.

"We expected to see that these animals would have more amyloid plaques," Moraes said. "But we got the opposite result," he said.

The animals without the COX10 gene actually developed fewer brain plaques than those with the gene, Moraes said. "Those animals also had less free radicals," he said.

The findings suggest that a defect in the COX10 gene develops after amyloid plaques develop, not the other way around, as has been thought, Moraes said.

"The mitochondrial defect in Alzheimer's disease appears to be a consequence of amyloid accumulation, not the cause of amyloid accumulation," he said. "Also, if you have a defect in the COX gene, you are not necessarily going to have more free radicals being formed," he added.

According to Moraes, the finding could have implications for scientists' understanding of the aging brain in general, not just Alzheimer's.

If the findings are duplicated in other research, they might be useful in developing new treatments for Alzheimer's -- treatments that target the COX gene, Moraes said.

One expert agreed that the findings shed new light on Alzheimer's disease.

"This study shows that a genetic manipulation that reduced the activity of a key energy-producing enzyme also reduced free radical damage and Alzheimer pathology in a mouse model," said Greg M. Cole, a neuroscientist at the Greater Los Angeles VA Healthcare System and associate director of the Alzheimer's Disease Research Center at UCLA's David Geffen School of Medicine.

"The results are consistent with other evidence that reducing free radicals can limit Alzheimer amyloid plaque pathology," Cole added. "Examples include reducing caloric intake or increasing antioxidant intake. So, even though clinical trials to treat Alzheimer's with [antioxidant] vitamin E have been disappointing, earlier and more effective reduction of free radical damage could mimic the success of this genetic approach and should still be pursued," he said.

More information

For more on Alzheimer's disease, visit the Alzheimer's Association.

SOURCES: Carlos T. Moraes, Ph.D., associate professor, neurology and cell biology and anatomy, University of Miami Miller School of Medicine, Florida; Greg M. Cole, Ph.D., neuroscientist, Greater Los Angeles VA Healthcare System, and associate director, Alzheimer's Disease Research Center, UCLA David Geffen School of Medicine, Los Angeles; Aug. 20-24, 2007, early edition, Proceedings of the National Academy of Sciences


Copyright©2007 ScoutNews,LLC.

Related medicine news :

1. Gene study links endometriosis, infertility
2. Study reveals how stress can make you sick
3. Study points out that HIV vaccine may not be accepted easily
4. A new study surpasses Gene Therapy Hurdle
5. Tomato Sauce reduces Cancer Risk- Study
6. A question on study of Adult Stem Cell
7. Study on obesity and heart failure
8. National Lung Study in the process
9. Marijuana gateway theory strengthened by study of twins
10. Old theory of adaptation confirmed by new study
11. Study casts doubt on keyboard ills
Post Your Comments:
(Date:11/30/2015)... , ... November 30, 2015 , ... According to Los ... people to overeat are not necessarily caused by real hunger, but instead by ... needs food. He notes that, while many patients are aware that weight loss surgery ...
(Date:11/30/2015)... (PRWEB) , ... November 30, 2015 , ... A record ... annual Regional Biotech Conference, organized by the Baruch S. Blumberg Institute. , The institute, ... of the area’s life science and biotechnology leaders for the conference, which focused on ...
(Date:11/30/2015)... ... 30, 2015 , ... A novel class of antimicrobials that ... in fighting methicillin-resistant Staphylococcus aureus (MRSA), one of the major drug-resistant bacterial pathogens, ... molecule analogs that target the functions of SecA, a central part of the ...
(Date:11/30/2015)... Scotch Plains, NJ (PRWEB) , ... November 30, ... ... is their top choice for innovative, patient centered orthopedic care. Led by ... Regardless of your injury or chronic condition, the team at Advocare Orthopedic & ...
(Date:11/30/2015)... (PRWEB) , ... November 30, 2015 , ... ... specializes in general dentistry out of Glen Ridge, NJ. He has both ... to achieve optimal mastication. He is also an expert in cosmetic dentistry. ...
Breaking Medicine News(10 mins):
(Date:11/30/2015)... , Nov. 30, 2015  QT Vascular Ltd., ... and together with its subsidiaries, TriReme Medical LLC and ... company engaged in the design, assembly and distribution of ... vascular disease, is pleased to announce that a three-judge ... Court of Appeals for the Federal Circuit ("Federal Circuit") ...
(Date:11/30/2015)... --  Royal Philips  (NYSE: PHG ; AEX: ... a fully integrated, consultative approach to enhance radiology ... management approaches that combine imaging systems, services, informatics ... delivery and reduce costs. Making its debut at ... Annual Meeting (RSNA) in Chicago ...
(Date:11/30/2015)... , Nov. 30, 2015 Nautilus Medical ... Radiology Image Management platform ( ). The release ... announced from RSNA 2015 (Radiology Society North America) in ... conference in the U.S. --> ... platform that enables access to radiology studies worldwide via ...
Breaking Medicine Technology: