The American Society for Microbiology held a meeting on May 22nd and announced that Helicobacter pylori – a bacterium found in the stomachs of about half the world’s population – may be an accomplice in triggering Parkinson’s disease. Rats infected with H. pylori have reduced dopamine synthesis in the area of the brain that controls movement, possibly signaling that dopamine-producing cells are dying, which is the same thing that happens in Parkinson’s disease patients. A nasty bacterium that is responsible for ulcers and stomach cancer has recently gained a new notoriety: Brain cells may be among its victims. Dongfeng Zhang, Zhengzhou People’s Hospital Brain Hospital Helicobacter pylori – a bacterium found in the stomachs of about half the world’s population – may be an accomplice in triggering Parkinson’s disease. The American Society for Microbiology held a meeting on May 22 to announce the findings. Parkinson’s disease is a neurological disorder that causes necrosis of dopamine-producing cells in the relevant areas of the brain, and people with the disease are unable to control their body movements on their own. In the United States, 60,000 people are diagnosed with Parkinson’s disease each year. According to previous studies, people with Parkinson’s disease are more likely to have a history of ulcers and are more likely to be infected with Helicobacter pylori than healthy people. But so far, cases of an association between H. pylori and Parkinson’s disease have been circumstantial at best. Researchers are currently gathering evidence that could potentially attribute at least part of the cause of Parkinson’s disease to the notorious bacteria. According to Traci Testerman, a microbiologist working at Louisiana State University’s Health Sciences Center, middle-aged white rats infected with H. pylori gradually showed abnormal movement over a months-long period of infection. Young rats infected with the same bacteria did not show any movement abnormalities. Testerman’s colleague, neuroscientist Michael Salvatore, found that rats infected with Helicobacter pylori had reduced synthesis of dopamine in the area of the brain that controls movement, possibly signaling that dopamine-producing cells are dying, which is the same as is the case in Parkinson’s disease patients. H. pylori does not have to be alive to cause disease. Feeding rats with killed H. pylori can have the same effect, suggesting that some biochemical substance in the organism is the culprit. One possible pathogenic molecule is denatured cholesterol. H. pylori cannot synthesize cholesterol on its own, so it steals cholesterol from its host and inserts a sugar molecule into it. Denatured cholesterol is structurally similar to a toxin produced by a plant in the tropical thujaplica family, and Guamanians who feed on the plant’s seeds suffer from a condition known as ALS-Parkinson’s dementia syndrome. Testerman and colleagues are working to determine whether denatured cholesterol on its own is enough to cause Parkinson-like symptoms in white rats or whether other components of the bacterium need to be involved. Even if scientists are able to prove that H. pylori is a direct or indirect cause of Parkinson’s disease, eradicating it completely may not be a good thing. Although H. pylori causes ulcers and stomach cancer, it also helps protect the organism from allergies, asthma and acid reflux diseases such as esophageal cancer. According to Stanley Maloy, a microbiologist at San Diego State University, it is unclear what effect the removal or retention of H. pylori will have on an individual. But one thing is clear, the possible link between Parkinson’s disease and H. pylori can no longer be ignored. Malloy says, “A great deal of facts are in front of us, and it would be a mistake not to take a closer look at this time.”