IL-10, IL-12 and IL-18 Levels in the Gingival Crevicular Fluid of Patients With Periodontitis and Healthy Controls
Condition: Periodontitis
MeSH terms: Periodontitis
Study type: Observational [Patient Registry]

Summary: 
      Periodontitis is a multifactorial chronic inflammatory disease characterized by the
      destruction of the tissues supporting the tooth. The incidence and rate of progression of
      periodontal destruction involves a complex interaction between periodontopathic bacteria and
      immune system cells. The complex cytokine network that mediates the immune response includes
      pro-inflammatory cytokines, anti-inflammatory cytokines, and specific cytokine receptors.
      Cytokines act as messengers to initiate, mediate, and control immune and inflammatory
      responses. It is known that the interaction of pro- and anti-inflammatory cytokines plays a
      very important role in the progression of periodontitis .

      The immune response to infection is regulated by the balance between T helper (Th)1 and
      Th2-type cytokines. Since Th1, Th2, and monocyte-derived cytokines in gingival tissues and
      gingival crevicular fluid (GCF) play a role in periodontal inflammation, even a minimal
      imbalance in cytokine production may affect the induction of bone and collagen resorption in
      periodontal disease. For this reason, cytokines in inflamed periodontal tissues, which are
      the focus of many studies, are of great importance in the progression of periodontal disease.

      In this study, our aim is to evaluate the local cytokine response in relation to the clinical
      periodontal status by determining the IL-10, IL-12 and IL-18 concentrations in the gingival
      crevicular fluid of individuals with grade B-C stage III-IV periodontitis according to the
      2017 Classification of Periodontal and Peri-implant Diseases and Conditions. In this way,
      besides clinical and radiographic determinations in the diagnosis of periodontal disease,
      IL-10, IL-12 and IL-18 are measured to evaluate whether these markers have an effect on the
      diagnosis of the disease.
    

Detailed description: 
      Interleukin-10 (IL-10) is one of the most potent anti-inflammatory cytokines, as it induces T
      cell anergy (non-responsiveness to an antigen) and reduces the production of some
      pro-inflammatory cytokines. Altered expression of IL-10, however, genetic predisposition and
      the presence of specific periodontal bacteria may contribute to the disruption of the Th1/Th2
      balance and the development of aggressive periodontitis.

      Interleukin-12 (IL-12) is a heterodimer comprised of p35 and p40 subunits, which form the
      bioactive IL-12 (p70). IL-12 is an essential mediator of the early innate immune response and
      a key inducer of cellular immunity. Its most important task is to stimulate T cells and
      interferon-γ (IFN-γ) production by natural killer cells, thereby promoting Th1 responses. The
      importance of IL-12 is not limited to initiating an immune response, it may contribute to the
      maintenance of immunity. Because in the absence of IL-12, Th1 responses are rapidly lost.

      Interleukin-18 (IL-18) is a pro-inflammatory cytokine belonging to the IL-1 cytokine family.
      This cytokine was originally identified as a natural killer and a cytokine that induces IFN-γ
      produced by T cells. IL-18 acts synergistically with IL-12 to support IFN-γ production and
      Th1 cell growth, but does not depend on IL-12 for its activity.

      When this information is brought together, the evaluation of the effects of IL-10, IL-12 and
      IL-18 concentrations in the gingival crevicular fluid on periodontal disease together with
      clinical parameters has been the point of our study.

      It is planned to include 30 periodontally healthy individuals with grade B-C stage III-IV
      periodontitis according to the 2017 Classification of Periodontal and Peri-implant Diseases
      and Conditions, who applied to Istanbul University Faculty of Dentistry Periodontology
      Department, after clinical and radiographic evaluations. All individuals to be included will
      be informed about the purpose and method of the study and their consent will be obtained.

      Before the study, it will be ensured that the oral condition of the individual is not caused
      by any other factor (unknown systemic disease, blood disease, etc.). The individuals included
      in the study; systemic and oral anamnesis, smoking status, systemic disease status will be
      recorded and the following clinical measurements will be made.

      Gingival crevicular fluid (GCF) samples will be taken from individuals suitable for the study
      model, and periodontal indices will be recorded. The levels of IL-10, IL-12 and IL-18 will be
      determined in the GCF samples taken. The researcher will not include individuals who have
      been included in other studies that have passed or will be approved by the ethics committee,
      and will not include individuals who will be included in this study, undertakes not to
      include it in its work.

      Clinical measurements include Plaque Index (PI), Gingival Index (GI), Bleeding on Probing
      (BOP), Probing Depth (PD), Free Gingival Margin (FGM), Clinical Attachment Level Measurement
      (CAL), Mobility parameters. The measurements were made by the same researcher from six
      different points of all teeth: mesio-buccal, mid-buccal, disto-buccal,
      mesio-lingual/palatinal, mid-lingual/palatinal, disto-lingual/palatinal. It will be measured
      and recorded by a single person with the Williams (Hu-Friedy, USA) type periodontal probe.
      These measurements are non-invasive and will enable us to determine the periodontal status.
      After the clinical examination and measurements of the patients who met the inclusion
      criteria and signed the voluntary consent form, the gingival crevicular fluid samples to be
      taken from the patients will be analyzed and the results will be evaluated. Samples will be
      isolated from the gingival groove with the aid of absorbent paper strips (Periopaper®,
      Proflow Inc., Amitiyville, NY, USA) and biochemical analyzes will be made in the samples
      obtained by ELISA method in accordance with the protocols included in the kit. Biochemical
      analyzes will be carried out at Istanbul University, Istanbul Faculty of Medicine, Department
      of Medical Biochemistry.

      The clinical evaluation methods planned to be applied in the study are listed below:

        1. Plaque Index

        2. Probing Depth

        3. Bleeding on Probing

        4. Clinical Attachment Level Measurement

        5. Free Gingival Margin

        6. Gingival Index

        7. Mobility Samples of paper strips (Periopaper®, Proflow Inc., Amitiyville, NY, USA)
           placed in the gingival groove will be placed in eppendorf tubes for laboratory
           examination in the session 1 week after the exact periodontal status is determined by
           periodontal measurements. Samples will be taken from areas with the deepest probable
           pocket depth. While obtaining gingival crevicular fluid samples, the area will be
           isolated with cotton pads and the microbial dental plaque on the tooth will be removed
           with cotton pellets, and then a short-term drying process will be done with air
           freshener from a 20 cm distance at a right angle. Then, standard absorbent 2x8 mm paper
           strips will be placed from the approximal regions to the entrance of the groove with
           slight resistance and after waiting for 30 seconds, each paper strip will be placed in
           an eppendorf tube and stored at -80°C. (New Brunswick Scientific Ultra Low Temperature
           Freezer). Samples will be taken from 6 teeth in each patient.

      In case of bleeding from the gingival groove during sample collection, the sample will not be
      taken from that area.

      GCF samples taken and stored at -80°C will be analyzed at Istanbul University, Istanbul
      Medical Faculty, Department of Medical Biochemistry. IL-10, IL-12 and IL-18 levels of GCF
      samples will be determined by ELISA method.

      In the light of the data, the clinical conditions and biochemical analyzes of the patients
      will be compared and the relationship between them will be examined.

      According to the 2017 Classification of Periodontal and Peri-implant Diseases and Conditions,
      an average of 11 units difference between the results obtained from interleukin biomarkers in
      the group of individuals with grade B-C stage III-IV periodontitis and healthy individuals,
      and a minimal sample to find the estimated 15-unit standard deviation significant size
      (assuming Type I error 5%, Type II error 20% assuming Power 0.80): 30 people for each group.
      Considering the wrong samples, 30+30 people will be taken into each group (30 healthy
      controls, 30 Periodontitis cases) Our study will be carried out on systemically healthy
      patients aged 18-65 years who were diagnosed with Grade B-C stage III-IV periodontitis
      according to the 2017 Classification of Periodontal and Peri-implant Diseases and Conditions
      in the Periodontology Clinic of Istanbul University Faculty of Dentistry.

      After the clinical examination and measurements of the patients who met the inclusion
      criteria and signed the voluntary consent form, the gingival crevicular fluid samples taken
      from the patients will be analyzed and the results will be evaluated. The samples will be
      isolated from the gingival crevicular with the help of the absorbent periopaper and
      biochemically analyzed with ELISA kits.

      Periodontitis group:

        -  18-65 years old

        -  Not having any systemic disease (diseases that do not affect the periodontal status)

        -  Non-smoker

        -  Have not received antibiotic treatment and/or used immunosuppressant medication in the
           last 6 months

        -  Have not received any periodontal treatment in the last 6 months

        -  No pregnancy and lactation

        -  Not using any medication regularly

        -  Having at least 20 teeth

        -  Grade B-C stage III-IV periodontal disease according to the 2017 Classification of
           Periodontal and Peri-implant Diseases and Conditions

      Healthy Group:

      In patients who applied to Istanbul University Faculty of Dentistry, Department of
      Periodontology, periodontally healthy individuals who do not meet the above disease criteria,
      who do not have a history of periodontitis in any way, will be included in the study.
      Consisted of individuals with clinically healthy gingiva on an intact periodontium who had a
      BOP score less than 10% and PD≤3mm, showed no attachment loss or radiographic bone loss.
    

Intervention name(s): No intervention was applied to the groups the samples will be collected in terms of the diagnosis ( periodontitis, healthy)
Intervention type(s): Other
Intervention description(s): No intervention was applied to the groups the samples will be collected in terms of the diagnosis (periodontitis, healthy)
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        In our study individuals who have Grade B-C stage III-IV periodontal disease according to
        the 2017 Classification of Periodontal and Peri-implant Diseases and Conditions and
        individuals who have healthy gingiva will be selected
      
Biospecimen description: 
      Gingival Crevicular Fluid
    
Keywords: periodontitis; healthy gingiva; grade b; grade c; stage III; stage IV