Monday, March 8, 2010

New kind of Prion disease impairing brain arteries apparently identified

National Institute Of HealthPrion diseases are said to be from a family of progressive conditions that may affect the nervous system in humans and animals. National Institutes of Health (NIH) scientists are examining how prion diseases may impair the brain. They have supposedly noted a type of disease in mice that may not cause the sponge-like brain deterioration usually observed in prion diseases. Instead, it appears to look like a kind of human Alzheimer’s disease, cerebral amyloid angiopathy that impairs brain arteries.
The study outcomes are said to be similar to discoveries from two recently accounted human cases of the prion disease Gerstmann-Straussler-Scheinker syndrome (GSS). This finding seems to stand for a new system of prion disease brain damage.

The function of a particular cell anchor for prion protein is said to be the core of the NIAID study. Standard prion protein apparently utilizes a particular molecule, glycophosphoinositol (GPI), to strap on to host cells in the brain and other organs. In their study, the NIAID experts genetically eliminated the GPI anchor from study mice, thereby averting the prion protein from attaching to cells and thus facilitating it to diffuse generously in the fluid outside the cells.

The study authors subsequently exposed those mice to contagious scrapie and monitored them for around 500 days to observe if they became sick. The experts recorded signals usual of prion disease counting weight loss, lack of grooming, gait abnormalities and inactivity. But when they checked the brain tissue, they did not view the sponge-like holes in and around nerve cells characteristic of prion disease. Instead, the brains seem to encompass huge buildups of prion protein plaques trapped outside blood vessels in a disease process called cerebral amyloid angiopathy, which apparently impairs arteries, veins and capillaries in the brain. Moreover, the standard pathway by which fluid drains from the brain is said to be obstructed.

Study author Bruce Chesebro, M.D., chief of the Laboratory of Persistent Viral Diseases at NIAID’s Rocky Mountain Laboratories apparently signifies that prion diseases may be split into two groups: those with plaques that damage brain blood vessels and those devoid of plaques that may result in the sponge-like impairment to nerve cells. Dr. Chesebro is of the opinion that the attendance or absence of the prion protein anchor could verify which type of disease develops.

The new mouse model utilized in the study and the two new human GSS cases, which also do not encompass the standard prion protein cell anchor, are claimed to be the first to encompass that in prion diseases, the plaque-associated damage to blood vessels may take place without the sponge-like impairment to the brain. If scientists may discover an inhibitor for the new kind of prion disease, they may also use the same inhibitor to treat similar kinds of damage in Alzheimer’s disease.

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