TONGUE coating analysis may offer a promising non-invasive approach for diagnosing Parkinson’s disease (PD), with distinct differences in microbial and metabolic profiles identified between patients and healthy controls. These findings pave the way for early detection and improved monitoring of PD progression.
Parkinson’s disease is a complex neurodegenerative disorder with currently limited diagnostic options that often rely on invasive procedures or clinical assessment. Non-invasive, cost-effective methods that capture biological changes related to PD could revolutionise diagnosis and management. This study investigated the potential of tongue coating (TC) samples, assessing both microbiome and metabolome components, to serve as diagnostic biomarkers for PD.
Researchers recruited 36 PD patients and 31 healthy controls and utilised 16S rRNA sequencing to profile microbial communities in TC samples. Significant alterations were observed, including changes in the relative abundances of Firmicutes, Bacteroidetes, and Actinobacteria. Metabolomics analysis using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry revealed lower levels of palmitoylethanolamide (PEA) among PD patients, with carnitine levels notably reduced in those at severe Hoehn-Yahr stages and with mild cognitive impairment. Machine learning models integrating microbiome and metabolome data achieved an accuracy of 88.9% in differentiating PD from controls. Pathway analysis highlighted enhanced metabolic activity in microbial communities, supporting the link between microbial shifts and disease processes.
These preliminary findings suggest TC sampling holds clinical potential as a diagnostic and monitoring tool for Parkinson’s disease. However, limitations such as small sample size, single-centre recruitment, and varied TC collection protocols must be addressed. Integrating microbiome and metabolome analyses with machine learning could aid earlier diagnosis and personalised treatment, ultimately improving patient outcomes.
Reference
Yang R et al. Microbiome and metabolome integrated analysis: exploring potential diagnostic approaches for parkinson’s disease using tongue coating samples. Frontiers in Microbiology. 2025;16:1621468.
