Dysregulation of melatonin rhythm in Parkinson’s and Huntington’s disease: a systematic review and meta-analysis

TL;DR

This study finds that melatonin levels are disrupted in Parkinson’s and Huntington’s diseases, suggesting it could help with early diagnosis and tracking disease progression.

Contribution

The study introduces melatonin as a potential early biomarker for Parkinson’s and a progression tracker for Huntington’s disease.

Findings

Melatonin rhythmicity is significantly disrupted in both Parkinson’s and Huntington’s disease patients.

Parkinson’s patients with sleep disorders have significantly higher melatonin concentrations.

Huntington’s disease shows a stage-wise decline in melatonin parameters.

Abstract

Parkinson’s disease (PD) and Huntington’s disease (HD) are progressive neurodegenerative diseases with early non-motor symptoms, such as sleep disturbances, which often precede motor symptoms but are frequently overlooked. Although HD can be diagnosed genetically, PD lacks reliable biomarkers for its early detection. Melatonin, a circadian regulator, may be a promising early biomarker to address this issue.

A database search was performed to identify relevant studies. Meta-analyses were conducted using the ratio of means (RoM) as an effect size and I2 as a heterogeneity test.

Melatonin rhythmicity was significantly disrupted in both PD and HD groups. PD patients showed reduced amplitude [RoM = 0.76, 95% CI (0.26 to 1.26); p = 0.00] and increased 24-h area under the curve (AUC) [RoM = 1.06, 95% CI (0.26 to 1.85); p = 0.01]. In manifest HD, both amplitude [RoM = 0.92, 95% CI (0.81 to 1.02); p = 0.00] and acrophase [RoM = 0.92, 95% CI (0.07 to 1.78); p = 0.03] significantly decreased. PD patients with sleep disorders had significantly higher melatonin concentrations than the non-sleep disorder group, with a significant test group difference of p = 0.00. HD patients showed a stage-wise decline.

This study suggests that melatonin could serve as a biomarker for the early diagnosis of PD and to track the progression of HD, thus complementing existing diagnostic tools.

CRD42024544116, https://www.crd.york.ac.uk/PROSPERO/view/CRD42024544116.

Figures