Reacción a "A study shows that changes in the gut microbiome can identify people at risk of developing Parkinson's disease"

Is the study of high quality?

“This study is methodologically sound. In addition to involving a large number of patients and controls, it includes, for the first time, individuals who, despite having the genetic mutation most closely associated with Parkinson’s, do not develop the disease. It also employs an innovative analysis of the microbiota, although I feel it should be supplemented with metabolomics—that is, not just identifying which bacteria are present, but also determining which metabolites they produce.”

Are there any limitations to consider?

“In the field of the microbiome, we can only compare patients and healthy individuals and observe the differences statistically, but we don’t know if this is a cause or a consequence. The authors themselves mention this, and now the next step is to validate these changes prospectively, as well as to incorporate metabolomic studies to identify what those bacteria are doing differently compared to healthy controls.”

What are the implications, and how does this fit with existing evidence?

“The biggest implication is that in individuals with mutations that predispose them to Parkinson’s, their gut microbiome resembles that of patients more than that of healthy individuals, suggesting that we should study these healthy mutation carriers with similar bacteria (to understand why they do not develop the disease or why it is delayed). This leads to the development of new lines of research, as well as predictive tests based on human and microbial genomics to assign the probability of developing Parkinson’s to a subject while they are still healthy.”

Alterations in the microbiota or digestive disorders have previously been associated with neurodegenerative diseases such as Parkinson’s. What conclusions can we begin to draw?

“This is the most difficult question to answer. Indeed, the focus has long been on the gut in relation to degenerative neurological diseases. Significant differences have been found between patients and controls, but no specific microorganism has been identified. This is not a microorganism infection, but rather a pathogenic colonization of an entire ecosystem, where it is not easy to pinpoint the specific cause. Despite changes in composition, we all believe that metabolic changes are more important, especially because these bacteria produce substances that can be neurotoxic, but they can also degrade others that are neuroprotective. There is much discussion about how the microbiota modifies drugs, and in the case of Parkinson’s disease, this is linked to microorganisms that degrade dopamine, which is why some patients stop responding to medication. Despite all the existing literature on the gut-brain axis, the specific mechanism associated with each disease has not yet been pinpointed, but we have no doubt that the microbiota contributes to neurodegenerative diseases, and specifically that Parkinson’s begins in the gut. One factor common to all of them is severe constipation, which prolongs bacterial fermentation of food; improving intestinal transit is key to preventing this overfermentation.”