Interferon-γ +874A/T polymorphism in relation to generalized chronic periodontitis and the presence of periodontopathic bacteria

BACKGROUND

Interferon gamma (IFN-γ) is one of the key regulatory cytokines that has a significant effect on immune responses. It may be important in the chronic inflammatory diseases such as periodontitis in which increased IFN-γ levels were found. The aim of this study was to analyze +874A/T polymorphism in the IFN-γ gene and its associations with the presence of periodontopathic bacteria and susceptibility to generalized chronic periodontitis (CP).

METHODS

A total of 498 unrelated Czech white subjects were included in the present study. Genomic DNA was obtained from the peripheral blood of 244 patients with CP and 254 healthy subjects. The IFN-γ +874A/T polymorphism was determined by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). Subgingival bacterial colonization (A. actinomycetemcomitans, P. gingivalis, P. intermedia, T. forsythia, T. denticola, P. micros, F. nucleatum in subgingival pockets) was investigated by the DNA-microarray based periodontal pathogen detection kit in a subgroup of subjects (N=110).

RESULTS

Our results showed no differences in the allele and genotype frequencies of the IFN-γ +874A/T polymorphism between patients with CP and controls (P>0.05). Although we found significant differences in the occurrence of periodontal bacteria between patients with CP and healthy controls (from P<0.00001 to P<0.05), no significant association between IFN-γ +874A/T polymorphism and periodontal pathogens was observed in any group.

CONCLUSIONS

In conclusion, these findings indicate that putative functional variant in the IFN-γ is not associated with susceptibility to chronic periodontitis or microbial composition in the Czech population.

Lack of association between chronic periodontitis and the Toll-like receptor 4 gene polymorphisms in a Czech population

BACKGROUND AND OBJECTIVE

Periodontitis is a bacterially induced chronic inflammatory disease and a major cause of tooth loss among adults. Toll-like receptors are signal molecules essential for the cellular response to bacterial cell wall components. The aim of this study was to investigate relationships between chronic periodontitis and variations in the TLR4 gene.

MATERIAL AND METHODS

A total of 171 patients with chronic periodontitis and 218 unrelated controls were genotyped for the Asp299Gly (896A>G) and Thr399Ile (1196C>T) polymorphisms of the TLR4 gene.

RESULTS

Both variants were in nearly complete linkage disequilibrium. No homozygotes for the less common alleles, 299Gly and 399Thr, respectively, were found. The prevalence of the Asp299Gly and the Thr399Ile heterozygotes was 5.3% and 5.0% in controls, and 7.0% and 7.0% in periodontitis patients.

CONCLUSION

In conclusion, TLR4 gene polymorphisms were not significantly associated with the susceptibility to, or severity of, chronic periodontitis in our population.

Genetic variations in the matrix metalloproteinase-1 promoter and risk of susceptibility and/or severity of chronic periodontitis in the Czech population

OBJECTIVES

Matrix metalloproteinase-1 (MMP-1) is a potent enzyme degrading extracellular matrix that was implicated in the pathogenesis of chronic periodontitis. Therefore, the aim of our study was to examine the association between three promoter polymorphisms of the MMP-1 gene and chronic periodontitis susceptibility and/or severity in a Czech population.

MATERIALS AND METHODS

A total of 329 Caucasian subjects were enrolled in this study. They were 133 patients with mild to severe chronic periodontitis and 196 unrelated control subjects. MMP-1 promoter polymorphisms (-1607 1G/2G, -519A/G, and -422A/T) were genotyped using standard polymerase chain reaction-restriction fragment length product methods.

RESULTS

Genotype analysis of the three single nucleotide polymorphisms across 27 different combinations showed significant association with chronic periodontitis (p<0.05). Analyses of individual polymorphisms showed no differences in distribution of the -519A/G and -422A/T variants between periodontitis and control groups. However, a trend to increased frequency of the -1607 1G allele was observed in patients with chronic periodontitis compared with the controls (p=0.054). When the groups were further stratified by smoking status, the 1G allele was associated with chronic periodontitis among non-smokers but not among smokers (p=0.033). On the contrary, the distribution of genotype frequencies of the MMP-1 -422A/T polymorphism was different between the patient and control smokers with respect to heterozygotes (73.91% versus 50.91%; p=0.017).

CONCLUSIONS

Our results demonstrate that the polymorphisms in the MMP-1 promoter may have only a small effect on the etiopathogenesis of chronic periodontitis.

Plasminogen-activator-inhibitor-1 promoter polymorphism as a risk factor for adult periodontitis in non-smokers

Periodontal diseases belong to the most common chronic disorders affecting mankind. Smoking and impaired plasminogen activation with hypercoagulation and fibrinolysis inhibition have been proposed as having a role in predisposition to these diseases. We investigated relationships among adult periodontitis, smoking, and a variation in the deletion/insertion (4G/5G) promoter polymorphism of the plasminogen-activator-inhibitor-1 (PAI-1) gene in 304 Caucasian subjects. An association was detected between the deletion (4G) allele (and 4G/4G genotype) and periodontitis (P = 0.0022, P(corr) < 0.01; P = 0.014, P(corr) < 0.05). A stronger association occurred in non-smokers (P = 0.00021, P(corr) < 0.01; P = 0.0024, P(corr) < 0.05) where the presence of the PAI-1 gene 4G allele appears to be one of the risk factors for periodontitis.

Distribution of the receptor for advanced glycation end products gene polymorphisms in patients with chronic periodontitis: a preliminary study

BACKGROUND

Periodontal diseases are viewed today as multifactorial problems initiated and sustained by bacteria but significantly modified by the body's response to bacterial plaque. A recent study suggested that receptor for advanced glycation end products (RAGE) could be involved in the pathophysiology of periodontitis. The aim of this study was to investigate a possible association of 3 common polymorphisms in the RAGE gene with chronic periodontitis.

METHODS

We studied 101 Caucasian patients with chronic periodontitis together with 162 orally healthy subjects. Three polymorphisms, one in intron 7 (1704G/T), second in intron 8 (2184A/G), and the third in exon 3 (G82S) of the RAGE gene, were investigated by polymerase chain reaction methods (PCR) with subsequent enzymatic restriction with Bfal, BsmFI, or Alu Il, respectively.

RESULTS

A statistically significant difference in allele frequencies between patients and the reference group was found for intron variant 1704G/T (P= 0.02, Pcorr >0.05). There was no significant difference in genotype or allele frequency distributions between groups for intron variant 2184A/G or for the exon variant exchanging amino acid Gly for Ser at position 82 (G82S).

CONCLUSIONS

We can speculate that susceptibility to the development of chronic periodontitis could be influenced by the 1704G/T polymorphism of the RAGE gene, independently of diabetes.

Interactions of lymphotoxin alpha (TNF-beta), angiotensin-converting enzyme (ACE), and endothelin-1 (ET-1) gene polymorphisms in adult periodontitis

BACKGROUND

Adult periodontitis is a complex multifactorial disease whose etiology is not well defined. To investigate whether the genes encoded within the HLA class III region may confer susceptibility to periodontitis, polymorphisms in the ET-1 and TNF-beta genes were analyzed together with the I/D polymorphism of the ACE gene.

METHODS

We determined allele and genotype frequencies of the NcoI bi-allelic polymorphism of the TNF-beta gene, the I/D (insertion/deletion) polymorphism of the ACE gene, and the TaqI polymorphism of the ET-1 gene in 63 Caucasian patients with adult periodontitis and 95 orally healthy controls.

RESULTS

We found a significant difference in a 3 locus combination of genotypes between patients and controls (P<0.05). In the next analyses, no significant differences were found in allele frequencies of single genes, but we did find a significant difference in the genotype distribution between cases and controls for TNF-beta (P<0.03). Differences were also observed for 2 locus combinations of ACE and TNF-beta genotypes (P<0.03), and the ET-1 and TNF-beta (P<0.05) genes. Evidence of deviation from Hardy-Weinberg equilibrium was observed in the periodontitis group for TNF-beta, with an absence of the B1B1 homozygotes in patients.

CONCLUSIONS

This study is of an exploratory nature. Considering the number of significant results, however, at least a part of the observed associations may obviously be real and our findings suggest that interactions of the TNF-beta, ET-1, and ACE genes may be involved in susceptibility to adult periodontitis.

[Standard of domiciliary care and hygienic habits of patients with prostheses]

By means of an enquiry on the standard of domiciliary dental care and hygienic habits of patients with prostheses the authors examined a total of 102 patients. They were divided into groups with natural teeth, removable dentures and fixed dentures which were their main interest. Patients with fixed dentures clean their teeth twice a day, only 18% clean their teeth for more than 2 minutes. The majority of patients prefer hard tooth-brushes. Other means than tooth paste are used by few: 36% of the patients reported massage, 7% irrigation, nobody uses a dental thread. Before prosthetic treatment 14% of the patients were examined by a periodontologist, 13% of the patients are invited to attend regular check-ups of prosthetic appliances. The hygienic standard is thus still inadequate. It is important to improve the motivation of patients for oral hygiene and intensify preventive periodontological and prosthetic cooperation.

[Condition of the periodontium in patients with fixed dentures]

The authors examined 29 patients with fixed prostheses. They investigated the condition of the periodontium of pillar teeth of these dentures and examined the vestibular and oral dental surfaces, the adjacent gingiva and the presence of microbial dental plaque. They recorded also the period of use of the denture. The periodontium was evaluated by Russel's according to Silness-Lö. In 16 dentures the assessed values ware compared with intact teeth on the contralateral side of the same jaw. The values of periodontal indices in pillar teeth of fixed prostheses are higher than in teeth without prosthetic treatment and they are proportional to the standard of hygiene and the period for which the prosthesis has been used.