TNF-α/HIF-1α/VEGF Pathway in Periodontal Diseases
Condition: Periodontal Diseases
MeSH terms: Periodontal Diseases
Study type: Observational

Summary: 
      This study aimed to investigate gingival crevicular fluid (GCF) and salivary hypoxia
      inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF) and tumor
      necrosis factor-alpha (TNF-α) levels in different periodontal diseases. A total of 87
      individuals, 20 patients with generalized aggressive periodontitis, 20 with chronic
      periodontitis, 26 with gingivitis and 21 periodontally healthy individuals were included.
      Whole-mouth and site-specific clinical periodontal parameters including probing depth,
      clinical attachment level, bleeding on probing, gingival index and plaque index were
      recorded. GCF and salivary HIF-1α, VEGF and TNF-α levels were measured by enzyme-linked
      immunosorbent assay. Statistical analysis was performed by using non-parametric tests.
    

Detailed description: 
      Study Population and Clinical Examination

      Eighty-seven participants were recruited for the study. Exclusion criteria were as follows:
      1) systemic diseases that could affect the periodontium; 2) smoking; 3) current pregnancy or
      lactation; 4) nonsurgical/surgical periodontal treatment received for the past year; and 5)
      use of anti-inflammatory and antibiotic drugs within the past 6 months.

      The full-mouth clinical periodontal examination included measurement of probing depth (PD),
      clinical attachment level (CAL), presence of bleeding on probing (BOP), gingival index (GI)
      and plaque index (PI) at 6 sites per tooth. Presence and extent of alveolar bone loss were
      assessed radiographically. Based on clinical and radiographic diagnostic criteria proposed by
      1999 International Workshop for a Classification of Periodontal Diseases and Conditions, the
      participants were categorized into four groups.

      I. Generalized aggressive periodontitis (GAgP) group (n=20). These individuals had minimum PD
      ≥6 mm and CAL ≥5 mm on eight or more teeth; at least three of these were other than central
      incisors or first molars. Radiographic alveolar bone loss was ≥30% of root length affecting
      at least three permanent teeth other than first molars and incisors. The severe destruction
      pattern was not commensurate with amount of plaque accumulation or other local risk factors
      for a given age.

      II. Chronic periodontitis (CP) group (n=20). These individuals had at least four non-adjacent
      teeth with sites with PD ≥6 mm and CAL ≥5 mm. They had also ≥50% alveolar bone loss in at
      least two quadrants that was commensurate with amount of plaque accumulation. BOP was >50% in
      the whole mouth.

      III. Gingivitis group (n=26). These individuals had varying degrees of gingival inflammation.
      They exhibited no sites with CAL >2 mm and no detectable alveolar bone loss in the
      radiography. BOP was >50% in the whole mouth.

      IV. Healthy group (n=21). These periodontally healthy volunteers exhibited no sites with PD
      >3 mm and CAL >2 mm as well as no radiographic evidence of alveolar bone loss. BOP was <15%
      in the whole mouth.

      Saliva sampling

      Whole unstimulated saliva samples were collected. Each participant was asked first to rinse
      the mouth completely with tap water for 2 minutes, wait for 10 minutes, and then expectorate
      into sterile polypropylene tube for 5 minutes.

      Gingival crevicular fluid (GCF) sampling

      Standardized filter paper strips were used for GCF sampling. Two GCF samples were taken from
      the buccal aspects of two non-adjacent interproximal sites of each individual. In patients
      with periodontitis, GCF were sampled from two sites exhibiting PD ≥6 mm and CAL ≥5 mm. GCF
      samples of gingivitis patients were obtained from the sites that exhibit BOP but no clinical
      attachment loss. In the healthy group, GCF samples were collected the sites exhibiting PD <3
      mm without BOP and clinical attachment loss.

      Measurement of hypoxia inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor
      (VEGF) and tumor necrosis factor-alpha (TNF-α) Levels in GCF and Saliva Samples

      HIF-1α, VEGF and TNF-α levels in GCF and saliva samples were measured by the enzyme-linked
      immunosorbent assay (ELISA) using commercial kits according to the manufacturer's guidelines.

      Statistical Analysis

      All data analyses were performed using a statistical software package. Comparisons of
      clinical and biochemical parameters between the study groups were performed using the
      Kruskal-Wallis test.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        All consecutive individuals were recruited from the Department of Periodontology, School of
        Dentistry, Adnan Menderes University, Aydın.
      
Biospecimen description: 
      Gingival crevicular fluid, saliva
    
Keywords: Periodontal disease; Hypoxia; Cytokines; Gingival crevicular fluid; Saliva