Study identifies ‘significant’ vascular anomalies in the brains of people with Huntington’s disease.


An international study led by researchers from Université Laval has identified significant vascular changes in the brains of people with Huntington’s disease. This breakthrough, the details of which are published in the journal Annals of Neurology, will have significant implications for understanding the disease and could open the door to new therapeutic targets for treating this fatal neurodegenerative condition.

The team state that Huntington’s disease is a hereditary neurodegenerative disorder that causes serious motor, cognitive, and psychiatric dysfunction and gradually leads to loss of autonomy and death. The disease develops in people age 40 to 50 on average. There is no cure and current treatments can only help control certain symptoms, but do not slow the neurodegenerative process. The disease affects roughly 1 in 10,000 people.

Although scientists have long known the cause of Huntington’s disease, little is known about the physiological processes associated with it, explain the team. Certain neurological diseases, such as Parkinson’s and Alzheimer’s, are accompanied by changes in the vasculature of the brain and in the blood-brain barrier, the interface that controls exchanges between the blood and the central nervous system. In the current study the team examined the brains of people affected by Huntington’s disease or who had died from it as well as a murine model of the disease to determine whether these changes are also present in Huntington’s disease.

The data findings show the presence of mutant huntingtin, the protein responsible for the disease, in all major components of the brain’s blood vessels. Affected brains also show higher blood vessel density and reduced blood vessel diameter.  The team explain that the abnormalities observed within the cerebral blood vessels were accompanied by an increased permeability of the blood-brain barrier, which could allow the pathological protein to propagate from the peripheral to the central nervous system.

The team are still unclear as to how this contributes to the development or progression of the disease.  However, the researchers explain that these results, along with their observations published in the same journal last year, strongly suggest that the disease is not solely the result of a phenomenon that is intrinsic to the cells i.e., the product of a genetic mutation, but rather that healthy cells can also be infected by the mutant protein.

The team surmise that these findings open up new avenues for treating Huntington’s disease, adding that if the transport of the mutant protein is facilitated by an increased permeability of the blood-brain barrier, the medical community could consider developing therapies aimed at reestablishing its integrity and preventing diseased peripheral cells from migrating to the brain.

Source:  Université Laval 

Schematic recapitulating findings collected both in R6/2 and HD patients as well as the hypothesized transport of mHtt to the brain by the transmigration of immune cells through the leaky BBB.  Cerebrovascular and blood–brain barrier impairments in Huntington's disease: Potential implications for its pathophysiology.  Cicchetti et al 2015.

Schematic recapitulating findings collected both in R6/2 and HD patients as well as the hypothesized transport of mHtt to the brain by the transmigration of immune cells through the leaky BBB. Cerebrovascular and blood–brain barrier impairments in Huntington’s disease: Potential implications for its pathophysiology. Cicchetti et al 2015.

 

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