Navigation Links
Blood flow in Alzheimer's disease

Researchers have discovered that the enzyme, endothelin converting enzyme-2 (ECE-2), may cause the decrease in blood flow in the brain seen in Alzheimer's disease and contribute to progression of the disease.

The study by Jennifer Palmer, BRACE/Reverend Williams PhD Scholar and colleagues at the University of Bristol's Dementia Research Group is published in the current issue [July 2009] of the American Journal of Pathology.

Alzheimer's disease is the most common form of dementia, affecting over half a million people in the UK - a figure expected to double in the next 20 years. Aβ peptide, which accumulates in the brain of Alzheimer's disease patients, is thought to lead to narrowing of the blood vessels and reduction of blood flood in the brain. ECE-2 may contribute to the disease by converting an inactive precursor to endothelin-1, which constricts blood vessels and further reduces blood flow.

Jennifer Palmer said: "Our findings raise the possibility that drugs that can block the actions of endothelin-1 and which are already licensed for treating other diseases may also be of benefit for the treatment of Alzheimer's disease."

Much of the funding for Jennifer Palmer's work comes from Bristol-based charity BRACE. The charity's Chief Executive, Mark Poarch added: "This is real progress and opens up new areas for research. It is also good news for the thousands of local people who have raised money to try to beat Alzheimer's. BRACE is stepping up its fundraising to help scientists press on and find a cure."

The researchers had been studying ECE-2 in human brain tissue that was donated to the South West Dementia Brain Bank at the University of Bristol because the enzyme is also able to break down Aβ peptide, which accumulates in Alzheimer's disease. They found that ECE-2 was markedly elevated in Alzheimer's disease. ECE-2 was particularly abundant in nerve cells in a part of the brain that is critical for memory and is severely affected by Alzheimer's disease.

The increase in ECE-2 in Alzheimer's disease is not simply a by-product of nerve cell damage. When the researchers looked at brain tissue from patients with a different type of dementia (vascular dementia), ECE-2 levels were normal no different from the levels in brain tissue from elderly people without dementia. Further studies showed that the increase seen in Alzheimer's disease of ECE-2 could not be explained by differences in age, gender or time to brain removal after death between the various groups of patients that were studied.

To investigate why ECE-2 might be specifically elevated in Alzheimer's disease, the researchers then examined nerve cells that were grown in a laboratory. They showed that addition of Aβ caused these nerve cells to increase their production of ECE-2. The findings indicate that nerve cells produce more ECE-2 when they are exposed to Aβ.

In the normal brain, blood flow responds to nerve cell activity. If nerve cell activity in a particular part of the brain increases, so does the supply of blood that is needed to meet the extra demand for nutrients such as glucose and oxygen. If this demand is not met, as can happen in Alzheimer's disease, the nerve cells may not function normally and may even sicken and die.

Although the elevated ECE-2 in Alzheimer's disease may help to break down amyloid beta, it may also cause the decrease in blood flow in the brain, through the production of too much endothelin-1. This may have important implications for treatment. Drugs are available that can block the actions of endothelin-1 and which have been shown to treat some other diseases in which excess endothelin-1 reduces blood flow. The findings raise the possibility that these drugs may also be of benefit for the treatment of Alzheimer's disease.


Contact: Joanne Fryer
University of Bristol

Related medicine news :

1. Alcohol and Trauma: Blood Test Gets to the Truth
2. Bone from blood: Circulating cells form bone outside the normal skeleton, Penn study finds
3. KLOS & Red Cross Set to Rock SoCal With Massive 5 Day Blood Drive
4. Gene Mutation Could Be Key to Rare Blood Vessel Disease
5. Cord Blood America CEO Discusses New State-of-the-Art State Laboratory in Fox News Television Interview
6. Orlando Regional Medical Center (ORMC) Implements PNA FISH(R) Tests to Help Provide Better Care for Patients with Bloodstream Infections
7. Gene linked to increasingly common type of blood cancer
8. High-Salt Diet Dampens Effects of Blood Pressure Drugs
9. Need for At-Home Blood Pressure Monitoring Underscored by High-Profile Cardiac Deaths
10. Cord Blood America Highlights Significant 2009 Progress
11. Blood Test Shows Statistically Significant Association With Alzheimers Disease (AD), May Predict Conversion of Mild Cognitive Impairment to AD
Post Your Comments:
(Date:11/26/2015)... ... November 26, 2015 , ... ... to discuss bioavailability and the need to integrate dose form selection in early ... with OBN, the membership organization supporting and bringing together the UK’s emerging life ...
(Date:11/26/2015)... Aliso Viejo, CA (PRWEB) , ... November 26, ... ... X users a new set of retro-fused, self-animating trailer titles with ProTrailer: Vintage. ... custom style options. These classically-influenced trailer titles work with any font, giving users ...
(Date:11/25/2015)... ... November 25, 2015 , ... As part of a ... ™ attracts volunteers together who want to combine talents and resources to help ... in the process. The non-profit launched its first major fundraiser on November 6, ...
(Date:11/25/2015)... MN (PRWEB) , ... November 25, 2015 , ... ... launched offering factory direct sauna parts and accessories. , Sauna accessories help ... of the bather’s style and personality. From basic styles for the purist looking ...
(Date:11/25/2015)... ... November 25, 2015 , ... For the first time, Vitalalert is donating ... Beat ” campaign. The partnership between the two groups began in 2014 with Vitalalert ... cause. , MAP International was founded in 1954 and is an international Christian-based health ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... November 26, 2015 Un nuevo ... Bremachlorin para el cáncer avanzado.   --> ... terapia fotodinámica de Bremachlorin para el cáncer avanzado. ... la inmunoterapia con la terapia fotodinámica de Bremachlorin para ... Research . --> Clinical Cancer Research . ...
(Date:11/26/2015)... , November 26, 2015 --> ... to use SyMRI to find optimal contrast weighting of MRI ... metastases, and has signed a research agreement with SyntheticMR in ... hospital. Using SyMRI, it is possible to generate multiple contrast ... after the patient has left, thus making it possible to ...
(Date:11/26/2015)... November 26, 2015 ... the "2016 Future Horizons and Growth ... Testing Market: Supplier Shares, Country Segment Forecasts, ... their offering. --> ) ... "2016 Future Horizons and Growth Strategies in ...
Breaking Medicine Technology: