Begin in gut before affecting the brain

Parkinson’s disease, which involves the malfunction and death of nerve cells in the brain , may originate in the gut, new research suggests, adding to a growing body of evidence supporting the idea.

The new study shows that a protein in nerve cells that becomes corrupted and then forms clumps in the brains of people with Parkinson’s can also be found in cells that line the small intestine. The research was done in both mice and human cells.

The finding supports the idea that this protein first becomes altered in the gut and then travels to the brain, where it causes the symptoms of Parkinson’s disease .

Parkinson’s disease is a progressive movement disorder, affecting as many as 1 million people in the United States and 7 million to 10 million people worldwide, according to the Parkinson’s Disease FoundationThe protein, called alpha-synuclein, is abundant in the brain . And in healthy nerve cells, it dissolves in the fluid within the cell. But in Parkinson’s patients, alpha-synuclein folds abnormally. The misfolded protein can then spread through the nervous system to the brain as a prion, or infectious protein. In the brain, the misfolded protein molecules stick to each other and clump up, damaging neurons.

In 2005, researchers reported that people with Parkinson’s disease who had these clumps in their brains also had the clumps in their guts. Other research published this year looked at people who had ulcers and who underwent a surgery that removed the base of the vagus nerve, which connects the brain stem to the abdomen. These patients had a 40 percent lower risk of developing Parkinson’s later in life compared with people who didn’t have their vagus nerve removed.