Tumor necrosis factor-alpha -308G/A single nucleotide polymorphism and red-complex periodontopathogens are independently associated with increased levels of tumor necrosis factor-alpha in diseased periodontal tissues.
OBJECTIVE
Inflammatory cytokines such as tumor necrosis factor-alpha are involved in the pathogenesis of periodontal diseases. A high between-subject variation in the level of tumor necrosis factor-alpha mRNA has been verified, which may be a result of genetic polymorphisms and/or the presence of periodontopathogens such as Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola (called the red complex) and Aggregatibacter actinomycetemcomitans. In this study, we investigated the effect of the tumor necrosis factor-alpha (TNFA) -308G/A gene polymorphism and of periodontopathogens on the tumor necrosis factor-alpha levels in the periodontal tissues of nonsmoking patients with chronic periodontitis (n = 127) and in control subjects (n = 177).


METHODS
The TNFA -308G/A single nucleotide polymorphism was investigated using polymerase chain reaction-restriction fragment length polymorphism analysis, whereas the tumor necrosis factor-alpha levels and the periodontopathogen load were determined using real-time polymerase chain reaction.


RESULTS
No statistically significant differences were found in the frequency of the TNFA -308 single nucleotide polymorphism in control and chronic periodontitis groups, in spite of the higher frequency of the A allele in the chronic periodontitis group. The concomitant analyses of genotypes and periodontopathogens demonstrated that TNFA -308 GA/AA genotypes and the red-complex periodontopathogens were independently associated with increased levels of tumor necrosis factor-alpha in periodontal tissues, and no additive effect was seen when both factors were present. P. gingivalis, T. forsythia and T. denticola counts were positively correlated with the level of tumor necrosis factor-alpha. TNFA -308 genotypes were not associated with the periodontopathogen detection odds or with the bacterial load.


CONCLUSIONS
Our results demonstrate that the TNFA -308 A allele and red-complex periodontopathogens are independently associated with increased levels of tumor necrosis factor-alpha in diseased tissues of nonsmoking chronic periodontitis patients and consequently are potentially involved in determining the disease outcome.
Trombone
A P F
AP
Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, São Paulo University, FMRP/USP, São Paulo, Brazil.
Cardoso
C R
CR
Repeke
C E
CE
Ferreira
S B
SB
Martins
W
W
Campanelli
A P
AP
Avila-Campos
M J
MJ
Trevilatto
P C
PC
Silva
J S
JS
Garlet
G P
GP
D000225:Adenine; D000328:Adult; D016976:Aggregatibacter actinomycetemcomitans / Q000502:physiology; D001439:Bacteroides / Q000502:physiology*; D055113:Chronic Periodontitis / Q000276:immunology* / Q000382:microbiology; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006147:Guanine; D006801:Humans; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000276:immunology / Q000382:microbiology; D010514:Periodontal Pocket / Q000276:immunology / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D016966:Porphyromonas gingivalis / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D048373:Treponema denticola / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D014409:Tumor Necrosis Factor-alpha; D006147:Guanine; D000225:Adenine