New Insights into the Causes of Dementia

Link:
http://www.biologynews.net/archives/2013/03/03/misplaced_molecules_new_insights_into_the_causes_of_dementia.html

Summary:

A new study showed that a shortage of TDP-43, a protein, caused muscle wasting and stunted nerve cells.  This supports the idea that a malfunction of this protein plays an important role in ALS and FTD.  ALS is a neurological disease that affects both limbs and respiratory muscles.  ALS leads to impaired mobility and breathing problems and usually leads to death a few years after the symptoms emerge.  Some people, such as Stephen Hawking, can live for a long time with the disease.  In Germany, it is estimated that 150,000 people suffer from ALS, which is an average of 1 in 500 people.  FTD is a form of dementia associated with personality changes and different social behavior.

Over the last few years, there has been and increase in evidence that ALS and FTD have similar origins.  The diseases have symptoms that overlap and have common factors.  Particles often accumulate and form clumps in nerve cells, which is what applies in particular to the TDP-43.  Dr. Bettina Schmid said, "Normally, this protein is located in the cell nucleus and is involved in processing genetic information.  However, in cases of disease, TDP-43 accumulates outside the nucleus forming aggregates."  It is currently unclear if the clumps are harmful, but scientists are sure that the protein's normal function is disrupted.  The protein no longer reaches the nucleus to perform its usual task.

In order to figure out what happens if the protein doesn't function, scientists investigated on the larvae of a specially bred zebrafish.  The genetic code of the zebrafish had been altered so that no TDP-43 would be produced.  The result of the study was that the fish showed massive muscle wasting and died soon after they were hatched.  The extensions of the nerve cells that control muscles were abnormal.  These are symptoms typical to ALS and FTD.  This made the scientists believe that a loss of the function of TDP-43 has a crucial role in the causes of the diseases.  The study also showed that the blood flow of the fish was disturbed.  Circulatory disorders play a part in other forms of dementia  such as Alzheimer's.  The scientists want to investigate if those problems with blood flow are a general problem of neurodegenerative diseases and if the same problems occur in patients with ALS and FTD.

NOS Themes:

Science is collaborative- "The team led by Bettina Schmid cooperated with the research group of Prof. Christian Haass..."
Science is based on evidence- "The result: the young fish showed massive muscle wasting and died a few days after hatching."
Role of motivation and curiosity- "We now want to investigate whether such problems with blood flow may be a general problem of neurodegenerative disease..."