Understanding how Parkinson’s disease starts and how it progresses remain two of the key unanswered questions about the disease. This is why a recent story in the New York Times caught my eye.
The article described how two independent groups of scientists found evidence that Alzheimer’s disease may spread from brain cell to brain cell much like a virus. These scientists engineered mice to make a human form of a protein called tau in only one small part of the brain. Clumps of the tau protein are a hallmark of Alzheimer’s disease. Like the rubble of demolished buildings, these clumps are all that are left of brains cells that have slowly died because of Alzheimer’s.
Proteins and Clumps
Proteins in the body are folded into special shapes … almost like pieces of origami. Some proteins, if they are not folded correctly to begin with or become “crumpled” due to some cellular problem, will stick together in clumps. Similar to how clumps of the protein tau are a hallmark of Alzheimer’s, clumps of a protein called alpha-synuclein are the hallmark by which Parkinson’s disease is diagnosed. These alpha-synuclein clumps are called Lewy bodies.
Parkinson’s and the Contagion Theory
Parkinson’s researchers have long noted what appears to be the spread of Lewy bodies from one brain region to another. Researchers observed possible clinical evidence that Parkinson’s could “spread” from one cell to another, when fetal cells were transplanted into the brains of people with Parkinson’s disease. The transplants subsequently developed Lewy bodies. That is, something about a Parkinson’s brain made genetically unrelated cells that were only a few years old develop the signs of Parkinson’s disease.
What came out of these observations was the controversial idea that Parkinson’s, once started, might be transmissible from brain cell to brain cell.
Several recent scientific papers are beginning to lend credence to this idea:
- Last year, Dr. Patrik Brundin’s research team in Lund, Sweden published a paper demonstrating that mis-folded alpha-synuclein (the basis of Lewy bodies) can spread from cell to cell in culture and could also spread in the brain of a mouse.
- More recently, Dr. Virginia Lee's team from the University of Pennsylvania published similar findings this past November.
- At a recent New York Academy of Sciences meeting on Parkinson’s disease, unpublished data was presented that also demonstrated how a single injection of alpha-synuclein clumps into a mouse brain could lead to the widespread formation of Lewy bodies in many different parts of the brain.
What Does It Mean?
Well it brings hope that a Parkinson’s therapy might be found in one of two ways: using special antibodies that target alpha-synuclein or a vaccine which primes the immune system to also target alpha-synuclein.
Either approach may not only halt the spread of Parkinson’s disease but maybe could also prevent it.
What do you think about the recent Alzheimer’s study and how it relates to Parkinson’s? As always, please share your comments and I will do my best to respond.