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NCT Number: NCT07182448

Hypoxia and Kynurenine Pathway in Periodontal Inflammation

The kynurenine pathway (KP), the primary route for tryptophan (TRP) metabolism, is activated during inflammation and hypoxic conditions, contributing to immune dysregulation and oxidative stress. the interconnected roles of hypoxia, KP activation, and oxidative stress in periodontitis have not been comprehensively investigated.The aim of this study was to determine the role of the kynurenine (KYN) pathway and hypoxia in periodontal inflammation, as well as their association with periodontal clinical parameters.

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Key information

Conditions

Periodontitis Diagnose Disease Hypoxia Mouth Diseases Pathological Conditions, Signs and Symptoms Periodontal Diseases Signs and Symptoms Signs and Symptoms, Respiratory Stomatognathic Diseases

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Istanbul Medipol University

Istanbul, Turkey (Türkiye)

About this study

Systemically healthy 23 stage III, grade B periodontitis patients and 22 periodontally healthy individuals were included in this study. Salivary and serum tumor necrosis factor-alpha (TNF-α), hypoxia-inducible factor-1 alpha (HIF-1α) and 8-hydroxy-2'-deoxyguanosine (8-OhdG) levels were evaluated by ELISA, and salivary and serum KP metabolites were evaluated by liquid chromatography-mass spectrometry.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

  • decline to participate and being under 18 & over 65 years of age;
  • having any systemic inflammatory diseases such as diabetes, rheumatoid arthritis, or systemic conditions, including immunodeficiency syndrome, cardiovascular disorders, or hepatic disorders;
  • the use of antibiotics and/or anti-inflammatory nonsteroidal anti-inflammatory drugs within 3 months preceding the study;
  • having nonsurgical periodontal treatment (previous 6 months);
  • having surgical periodontal treatment (previous 12 months);
  • having <20 natural teeth excluding the third molars.

Treatment and study plan

Saliva and serum sampling

Other

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 (MFD) from each participant. Saliva and serum were then stored at -80 °C until analysis.

Primary outcomes

  1. Pocket probing depth

    Time frame: 3 months

    Measurement 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

  2. Clinical attachment level

    Time frame: 4 months

    Clinical 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)

  3. Bleeding on probing

    Time frame: 4 months

    Bleeding on probing referring 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 outcomes

  1. serum and saliva analyses for selected molecules

    Time frame: 3 months

    ELISA method was used for tumor necrosis factor-alpha (TNF-α), hypoxia-inducible factor-1 alpha (HIF-1α) and 8-hydroxy-2'-deoxyguanosine (8-OhdG) levels evaluation. KP metabolites were evaluated by liquid chromatography-mass spectrometry.

Sponsors and collaborators

Lead sponsor

Istanbul Medipol University Hospital

Other

Collaborators

  • Ankara University

Registry information

Official study title

Interaction of Hypoxia and Kynurenine Pathway in Periodontal Inflammation

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Sep 19, 2025
Registry last updated
Sep 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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