Kynurenic Acid and Serotonin as Perioperative Neuroinflammatory Biomarkers in Sequential Third Molar Surgery (KYNA-3M)

June 13, 2026 updated by: Deyan Neychev, Plovdiv Medical University

Influence of Serotonin and Kynurenic Acid on Postoperative Pain, Neuroinflammation and Anxiety Following Surgical Removal of Impacted Mandibular Third Molars

A prospective cohort of 40 consecutive patients with bilateral impacted mandibular third molars underwent two sequential surgical extractions separated by a two-week interval. Serum kynurenic acid (KYNA) and serotonin were measured preoperatively and 24 hours after each procedure. The study examined longitudinal dynamics of kynurenine pathway biomarkers, their variation across Pederson surgical difficulty grades, and their relationship with postoperative pain and state anxiety.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Participants were randomised to placebo, ibuprofen 400 mg, or ibuprofen 400 mg plus gabapentin 300 mg administered preemptively 1 hour before incision and continued at 8-hourly intervals for 24 hours. Blood samples were collected at four timepoints (T0 Op1, T24 Op1, T0 Op2, T24 Op2) and analysed by ELISA for serum KYNA and serotonin. Postoperative pain was assessed by VAS at 2, 6, 12, 24, 48, and 72 hours. State-trait anxiety was assessed using the STAI Form Y before each operation. Pederson difficulty index was applied independently by two calibrated examiners. The biomarker analysis is reported observationally with pharmacological allocation treated as a covariate. Clinical data and samples were collected at the Department of Oral Surgery, Faculty of Dental Medicine, Medical University of Plovdiv, Bulgaria, during 2017-2018; laboratory biomarker analyses were conducted under Project No. DPDT-12/2019, Medical University of Plovdiv, and completed in 2020.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Bulgaria
    • Plovdiv
      • Plovdiv, Plovdiv, Bulgaria, 4002
        • Faculty of Dental Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Bilateral impacted mandibular third molars requiring surgical extraction
  • Age 18-38 years
  • Written informed consent
  • Ability to comply with study procedures

Exclusion Criteria:

  • Systemic inflammatory disease
  • Autoimmune disease
  • Neurological disease
  • Psychiatric disorders
  • Chronic pain conditions
  • Use of immunomodulatory medications
  • Use of psychotropic medications
  • Use of analgesic medications
  • Pregnancy
  • Drug hypersensitivity
  • Active pericoronitis at enrollment

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Placebo
Identical-appearing capsules administered 1 hour before incision, repeated every 8 hours for 24 hours. N=10.
Drug: Placebo
Identical-appearing oral capsules administered preemptively 1 hour before incision and every 8 hours for 24 hours.
Active Comparator: Ibuprofen
Ibuprofen 400 mg oral capsules administered 1 hour before incision, repeated every 8 hours for 24 hours. N=15
Drug: Ibuprofen
Ibuprofen 400 mg oral capsules administered preemptively 1 hour before incision and every 8 hours for 24 hours.
Experimental: Ibuprofen + Gabapentin
Ibuprofen 400 mg plus Gabapentin 300 mg oral capsules administered 1 hour before incision, repeated every 8 hours for 24 hours. N=15
Drug: Ibuprofen + Gabapentin
Ibuprofen 400 mg plus Gabapentin 300 mg oral capsules administered preemptively 1 hour before incision and every 8 hours for 24 hours.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Serum kynurenic acid (KYNA) concentration
Time Frame: Preoperative baseline and 24 hours postoperative at each operation
Change in serum KYNA from preoperative baseline (T0) to 24 hours postoperative (T24) at each of two sequential operations, assessed by ELISA
Preoperative baseline and 24 hours postoperative at each operation
Serum serotonin concentration
Time Frame: Preoperative baseline and 24 hours postoperative at each operation
Change in serum serotonin from preoperative baseline (T0) to 24 hours postoperative (T24) at each of two sequential operations, assessed by ELISA
Preoperative baseline and 24 hours postoperative at each operation

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Postoperative pain intensity
Time Frame: 2, 6, 12, 24, 48, and 72 hours postoperative at each operation
Pain assessed using a 100 mm Visual Analogue Scale (VAS; 0 = no pain, 100 = worst imaginable pain)
2, 6, 12, 24, 48, and 72 hours postoperative at each operation
State anxiety
Time Frame: Preoperative baseline at each operation
Preoperative state anxiety assessed using the State-Trait Anxiety Inventory (STAI Form Y), State subscale
Preoperative baseline at each operation
KYNA variation across Pederson surgical difficulty grades
Time Frame: 24 hours postoperative at Operation 1
Serum KYNA at 24 hours postoperative compared across Pederson difficulty grades (5-9), assessed by Kruskal-Wallis test
24 hours postoperative at Operation 1

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Plovdiv Medical University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Radka Ivanova Masaldzhieva, Dept. of Health Care Management, Faculty of Public Health, MU-Plovdiv
Mariya Vlado Ivanovska, Dept. of Microbiology and Immunology, Faculty of Medicine, MU-Plovdiv
Ralitsa Dimitrova Raycheva, Dept. of Social Medicine and Public Health, Faculty of Public Health, MU-Plovdiv

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Deyan Neychev, MD, PhD, Medical University of Plovdiv

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 30, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 17, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2020

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 8, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 12, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 16, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 13, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • DPDT-12/2019
  • Protocol No. P-604/28.02.2020 (Other Identifier: Ethics Committee MU-Plovdiv)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data are not planned for public sharing. Anonymized data are available from the corresponding author on reasonable request.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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