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Kynurenine Pathway in Parkinson's Disease

Periodontal Inflammation and Tryptophan-Kynurenine Metabolism in Parkinson's Disease

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07272564
Enrollment
60
Registered
2025-12-09
Start date
2022-05-15
Completion date
2023-06-18
Last updated
2025-12-09

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Inflammation, Periodontal Diseases

Keywords

periodontal disease, Tryptophan, Kynurenine

Brief summary

Parkinson's disease is a slowly progressing disease that affects the motor and non-motor functions of an individual. Periodontitis is an inflammatory chronic disease resulting in the destruction of tooth supporting structures. Inflammation has been identified as an important factor in both diseases. Given this common mechanism, the question arises as to how they may affect each other when both diseases occur together. In this study, we compared the metabolism of tryptophan, a natural amino acid of the human body, and observed whether such a process provides a biological link between periodontitis and Parkinson's disease. We extracted the saliva and blood samples of patients of Parkinson's disease and periodontitis, patients of periodontitis and healthy human beings. Comparisons between the three were made, and it was found that levels of some metabolites of tryptophan were higher in the patients of both diseases. These findings raise the possibility of a close biological connection between periodontal and brain health. Through an increased understanding of this connection in the future, new approaches for diagnosis and treatment of Parkinson's disease and periodontitis may be developed.

Detailed description

Saliva and serum samples were collected from 20 Stage III, Grade B periodontitis patients with PAD (Parkinson+periodontitis group) and without PAD (periodontitis group), and 20 periodontally and systemically healthy (control group). Samples were analyzed for TRP, KYN, KYN/TRP ratio, KYNA, 3OHKYN, picolinic acid (PA), and quinolinic acid (QA) by liquid chromatography-mass spectrometry. Clinical periodontal parameters \[plaque index (PI), probing pocket depth (PPD), clinical attachment loss (CAL), and bleeding on probing (BOP)\] were recorded.

Interventions

Saliva were collected to analyze the selected markers as unstimulated samples during the early hours of the day. The saliva was centrifuged and then transferred into Eppendorf tubes. Venous puncture was performed after saliva collection and 10 mL of blood samples were collected by qualified staff from each participant. Saliva and serum were then stored at -80 °C until analysis.

Saliva were collected to analyze the selected markers as unstimulated samples during the early hours of the day. The saliva was centrifuged and then transferred into Eppendorf tubes. Venous puncture was performed after saliva collection and 10 mL of blood samples were collected by qualified staff from each participant. Saliva and serum were then stored at -80 °C until analysis.

Sponsors

Medipol University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
PREVENTION
Masking
NONE

Intervention model description

Saliva and serum samples were collected from periodontitis patients and with Parkinson's +periodontitis patients. Samples were analyzed for TRP, KYN, KYN/TRP ratio, KYNA, 3OHKYN, picolinic acid (PA), and quinolinic acid (QA) by liquid chromatography-mass spectrometry.

Eligibility

Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
Yes

Inclusion criteria

* systemically healthy * clinical diagnosis of periodontitis * clinical diagnosis of periodontal health

Exclusion criteria

* history of regular use of systemic antibiotics anti-inflammatory, or antioxidant drugs (previous 3 months) * nonsurgical periodontal treatment (previous 6 months) * surgical periodontal treatment (previous 12 months) * presence of\<10 teeth * current medications affecting gingival health (calcium channel blockers, phenytoin, cyclosporine, and hormone replacement therapy) * diabetes * diagnosis of rheumatoid arthritis * pregnancy * lactating * smoking * excessive alcohol consumption.

Design outcomes

Primary

MeasureTime frameDescription
Pocket probing depth6 monthsMeasurement of the depth of a sulcus or periodontal pocket determined by measuring distance from a gingival margin to the base of the sulcus or pocket with a calibrated periodontal probe.
Clinical attachment level6 monthsClinical attachment level (or loss, CAL) is a more accurate indicator of the periodontal support around a tooth than probing depth alone. CAL is measured from a fixed point on the tooth that does not change, the CEJ. To calculate CAL, two measurements are needed: distance from the gingival margin to the CEJ and probing depth. In recession: probing depth (+) gingival margin to the CEJ (add). In tissue overgrowth: probing depth (-) gingival margin to the CEJ (subtract)
Bleeding on probing6 monthsreferring to bleeding that is induced by gentle manipulation of the tissue at the depth of the gingival sulcus, or interface between the gingiva and a tooth.

Secondary

MeasureTime frameDescription
Saliva and serum samples processing and analyses1 monthSamples were analyzed for TRP, KYN, KYN/TRP ratio, KYNA, 3OHKYN, picolinic acid (PA), and quinolinic acid (QA) by liquid chromatography-mass spectrometry.

Countries

Turkey (Türkiye)

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 26, 2026