ArticlePloS one2018
Biomarker repurposing: Therapeutic drug monitoring of serum theophylline offers a potential diagnostic biomarker of Parkinson's disease.
Article in PloS one, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 8 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
8 citing papers in PubMed, 17 citations in OpenAlex.
- Effect of Probiotics Supplementation on REM Sleep Behavior Disorder and Motor Symptoms in Parkinson's Disease: A Pilot Study.CNS neuroscience & therapeutics · 2025Trial
- The potential role of adenosinergic pathway and methylxanthines in Parkinson's disease: Blowing in the wind or not.Purinergic signalling · 2026Review
- Article
- Nanotechnological approaches for diagnosis and treatment of ovarian cancer: a review of recent trends.Drug delivery · 2022Review
- [Adenosine A2A Receptor Antagonists as a Treatment Option for Parkinson's Disease?]Fortschritte der Neurologie-Psychiatrie · 2022Article
- Untargeted serum metabolomic profiling for early detection ofFrontiers in cellular and infection microbiology · 2022Article
- Methylxanthines and Neurodegenerative Diseases: An Update.Nutrients · 2021Review
- Quantification of Blood Caffeine Levels in Patients With Parkinson's Disease and Multiple System Atrophy by Caffeine ELISA.Frontiers in neurology · 2020Article
Corrections and comments
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Authors and funding
9 authors at 3 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Caffeine has been considered a neuroprotective agent against Parkinson's disease (PD). Recent metabolomic analysis showed that levels of caffeine and its metabolites were decreased in sera from patients with PD compared with those from healthy controls. We focused on theophylline, which is one of the primary caffeine metabolites, as a candidate biomarker of PD because: (1) its serum level can be measured in hospital laboratories by standardized immunoassay kits for therapeutic drug monitoring and (2) because it is less markedly affected by caffeine intake. This was a pilot study to measure the levels of theophylline in sera of 31 patients with PD and 33 age-matched disease controls using an immunoassay kit. We confirmed the previous finding of significantly lower levels of serum theophylline in the PD group compared with control group (PD: 0.07±0.09 μg/mL, control: 0.18±0.24 μg/mL, p<0.05). Using such an approach of applying known medical biomarkers for neurodegenerative diseases may allow us to skip the process from the discovery phase to clinical application, and subsequently shorten the period of time necessary for biomarker development.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.