New Delhi: Changes to the composition of about a quarter of gut microbial species in individuals carrying a variant of the GBA1 gene — associated with an increased risk of Parkinson’s disease — may indicate a higher chance of developing the neurodegenerative condition, according to a study.
The findings, published in the journal Nature Medicine, suggests that biological changes linked to Parkinson’s disease may emerge prior to the onset of clinical symptoms, which could potentially help identify people in early stages of disease development.
Researchers, including those from University College London, said that motor and non-motor symptoms of the condition often appear only after substantial neuron loss has occurred.
Increasing evidence suggests that changes to one’s gut microbiome accompany both established Parkinson’s disease and the prodromal phase — the period during which subtle symptoms may precede diagnosis.
Patients of Parkinson’s disease have been studied to experience gastrointestinal issues, including constipation and gastroparesis.
The team analysed clinical and faecal data from participants from the UK and Italy: 271 people with Parkinson’s disease, 43 carriers of the GBA1 variant with no clinical symptoms, and 150 healthy control participants.
The analysis revealed 176 microbial species that differed between healthy individuals and those having the neurodegenerative condition, with over a quarter of the gut microbiome changing abundance between the two groups.
Of the 176, 142 species were seen to change consistently between healthy individuals and those carrying the GBA1 variant but do not have symptoms of Parkinson’s disease.
Further, among the GBA1 carriers, the microbial species of the microbiome resembled an intermediate pattern between that of healthy and affected groups, with its extent correlated with early symptoms.
The authors observed similar microbial patterns in three external cohorts in the US, Korea, and Turkey, totalling an additional 638 cases of Parkinson’s disease and 319 healthy participants.
These findings identify a distinct pattern in the gut bacteria of people who carry a GBA1 genetic variant but do not yet have symptoms, pointing to early biological changes linked to Parkinson’s disease.
However, the authors said that the study was a cross-sectional one — analysing data at a single, specific point in time, providing a ‘snapshot’ of characteristics — and therefore, cannot determine whether microbiome changes are predictive of future disease.
Longitudinal following individuals over time will be necessary to establish whether the microbiome can reliably identify those most likely to develop Parkinson’s disease, they said.
