Cyclooxygenase-2 expression in gingival biopsies from periodontal patients is correlated with connective tissue loss

The Role of Polymorphisms at the Interleukin-1, Interleukin-4, GATA-3 and Cyclooxygenase-2 Genes in Non-Surgical Periodontal Therapy

Periodontitis is a multifactorial disease. The aim of this explorative study was to investigate the role of Interleukin-(IL)-1, IL-4, GATA-3 and Cyclooxygenase-(COX)-2 polymorphisms after non-surgical periodontal therapy with adjunctive systemic antibiotics (amoxicillin/metronidazole) and subsequent maintenance in a Caucasian population. Analyses were performed using blood samples from periodontitis patients of a multi-center trial (ClinicalTrials.gov NCT00707369=ABPARO-study). Polymorphisms were analyzed using quantitative real-time PCR. Clinical attachment levels (CAL), percentage of sites showing further attachment loss (PSAL) ≥1.3 mm, bleeding on probing (BOP) and plaque score were assessed. Exploratory statistical analysis was performed. A total of 209 samples were genotyped. Patients carrying heterozygous genotypes and single-nucleotide-polymorphisms (SNP) on the GATA-3-IVS4 +1468 gene locus showed less CAL loss than patients carrying wild type. Heterozygous genotypes and SNPs on the IL-1A-889, IL-1B +3954, IL-4-34, IL-4-590, GATA-3-IVS4 +1468 and COX-2-1195 gene loci did not influence CAL. In multivariate analysis, CAL was lower in patients carrying GATA-3 heterozygous genotypes and SNPs than those carrying wild-types. For the first time, effects of different genotypes were analyzed in periodontitis progression after periodontal therapy and during supportive treatment using systemic antibiotics demonstrating a slight association of GATA-3 gene locus with CAL. This result suggests that GATA-3 genotypes are a contributory but non-essential risk factor for periodontal disease progression.

The Photomodulation Activity of Metformin Against Oral Microbiome

Periodontitis is one of the most common inflammatory diseases of the periodontium, which results in the inflammatory destruction of supporting structures around teeth and is closely associated with the development of systemic disease. Due to a wide variety of antibiotic resistance periodontopathic bacteria, photodynamic therapy (PDT) is a non-invasive adjunctive therapeutic modality that is capable of destroying the whole range of microbes. Metformin (Metf) is an antidiabetic drug, and recent studies suggest that cancer patients who receive Metf and are exposed to radiotherapy and chemotherapy show better outcomes. Our surveys in this review introduce Metf as a potent stimulus in increasing the efficacy of PDT in the induction of destruction in microbial cells.

Assessment of microRNA-144-5p and its putative targets in inflamed gingiva from chronic periodontitis patients

BACKGROUND AND OBJECTIVE

This study aimed to discover the distinctive MicroRNAs (miRNA) functioning in the pathogenesis of periodontal inflammation, which might be potential therapy targets of chronic periodontitis.

MATERIAL AND METHODS

miRNA profiles of human inflamed gingival tissue from three previous microarrays were re-analysed. Gingival tissues were collected for the validation of overlapping miRNAs, and a network was constructed to show regulatory connection between overlapping miRNAs and periodontitis-associated target genes. Potential miRNAs were screened based on their expression levels and predicted target genes. Correlation analysis and binding site prediction were conducted to reveal the relationship between the potential miRNAs and their target genes.

RESULTS

miR-144-5p, found to be upregulated in all three studies, showed the greatest upregulation (P < 0.0001). Another 16 miRNAs (10 upregulated and six downregulated) overlapped between any two of the three studies. All overlapping miRNAs had expected expression levels except for miR-203 during validation. Ten miRNAs (six upregulated and four downregulated) were found to have periodontal inflammation-associated targets. Cyclooxygenase 2 (COX2) and interleukin-17F (IL17F), predicted target genes of upregulated miR-144-5p, showed significant decreases and were negatively correlated with miR-144-5p in the periodontitis group (r = -0.742 for COX2, r = -0.615 for IL17F).

CONCLUSION

This re-analysis of miRNA signatures has implied the potential regulatory mechanism of miR-144-5p and its potential for exploring alternative therapeutic approaches, especially those that use miRNA delivery systems to treat chronic periodontitis. Nevertheless, further study based on larger sample size and homogenous cells is needed to reveal the exact roles of miRNAs in chronic periodontitis.

Regulation of inflammation by lipid mediators in oral diseases

Lipid mediators (LM) of inflammation are a class of compounds derived from ω-3 and ω-6 fatty acids that play a wide role in modulating inflammatory responses. Some LM possess pro-inflammatory properties, while others possess proresolving characteristics, and the class switch from pro-inflammatory to proresolving is crucial for tissue homeostasis. In this article, we review the major classes of LM, focusing on their biosynthesis and signaling pathways, and their role in systemic and, especially, oral health and disease. We discuss the detection of these LM in various body fluids, focusing on diagnostic and therapeutic applications. We also present data showing gender-related differences in salivary LM levels in healthy controls, leading to a hypothesis on the etiology of inflammatory diseases, particularly Sjögren's syndrome. We conclude by enumerating open areas of research where further investigation of LM is likely to result in therapeutic and diagnostic advances.

Wild Bitter Melon Leaf Extract Inhibits Porphyromonas gingivalis-Induced Inflammation: Identification of Active Compounds through Bioassay-Guided Isolation

Porphyromonas gingivalis has been identified as one of the major periodontal pathogens. Activity-directed fractionation and purification processes were employed to identify the anti-inflammatory active compounds using heat-killed P. gingivalis-stimulated human monocytic THP-1 cells in vitro. Five major fractions were collected from the ethanol/ethyl acetate extract of wild bitter melon (Momordica charantia Linn. var. abbreviata Ser.) leaves and evaluated for their anti-inflammatory activity against P. gingivalis. Among the test fractions, Fraction 5 effectively decreased heat-killed P. gingivalis-induced interleukin (IL)-8 and was subjected to separation and purification by using chromatographic techniques. Two cucurbitane triterpenoids were isolated from the active fraction and identified as 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol (1) and 3β,7β,25-trihydroxycucurbita-5,23-dien-19-al (2) by comparing spectral data. Treatments of both compounds in vitro potently suppressed P. gingivalis-induced IL-8, IL-6, and IL-1β levels and the activation of mitogen-activated protein kinase (MAPK) in THP-1 cells. Both compounds effectively inhibited the mRNA levels of IL-6, tumor necrosis factor (TNF)-α, and cyclooxygenase (COX)-2 in P. gingivalis-stimulated gingival tissue of mice. These findings imply that 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol and 3β,7β,25-trihydroxycucurbita-5,23-dien-19-al could be used for the development of novel therapeutic approaches against P. gingivalis infections.

Elevated levels of cyclooxygenase 1 and 2 in human cyclosporine induced gingival overgrowth

OBJECTIVE

This study was carried out to immuno-localize and estimate the levels of cyclooxygenase 1 and 2 in human gingival tissue samples from healthy individuals, chronic periodontitis patients and patients with cyclosporine induced gingival overgrowth.

METHODS

Group I consisted of individuals with healthy gingiva (n=6), Group II - cyclosporine induced gingival overgrowth (n=9) and Group III - chronic periodontitis patients (n=6). Gingival tissue samples were collected from subjects of all the three groups. COX-1, COX-2 levels were estimated in tissue homogenates by enzyme activity assay. Immuno-localization for COX-1 and COX-2 was also done in sections of gingival tissue.

RESULTS

The study results demonstrated a significantly higher mean levels of COX-1 and 2 in drug induced gingival overgrowth samples (p<0.05). COX-1 and COX-2 was localized to epithelium and connective tissue in human gingival tissue sections from cyclosporine induced gingival overgrowth.

CONCLUSION

Cyclooxygenase enzymes appear to be potential mediators involved in the pathogenesis of cyclosporine induced gingival overgrowth.

Association between COX-2 rs 6681231 genotype and interleukin-6 in periodontal connective tissue. A pilot study

OBJECTIVES

The aim of this pilot study was to investigate associations between IL-6 and COX-2 expression in gingival biopsies and both clinical diagnosis and genotypes in the IL-6 and COX-2 genes.

DESIGN

A case-control study included 41 gingival biopsies obtained from Caucasian patients grouped according to clinical diagnosis of gingival health (n = 10), gingivitis (n = 15) or chronic periodontitis (n = 16). Immunohistochemistry analyses were performed to determine COX-2 expression in lamina propria, IL-6 expression in lamina propria and gingival epithelium and level of inflammatory cell infiltrate. Individual DNA was extracted and genotyped by real-time PCR for IL6 SNPs rs 2069827 and rs 2069825 and for COX-2 rs 6681231.

RESULTS

The percentage of cellular COX-2 expression was associated with the extent of periodontal disease (Arbes index p = 0.026) and inflammatory infiltrate (p<0.0001). No association was observed between IL6 haplotypes and cells positive to IL-6 or COX-2 in gingival tissues. The COX-2 rs 6681231 was associated with cells positive to IL-6 in the connective tissue (p = 0.032).

CONCLUSIONS

COX-2 expression in gingival tissues may be a marker of periodontal disease severity. COX-2 rs 6681231 may be associated with IL-6 local production in gingival tissues.

COX-2 gene polymorphisms and risk of chronic periodontitis: a case-control study and meta-analysis

OBJECTIVE

Cyclooxygenase-2 (COX-2) enzyme is a major mediator of inflammation in periodontitis, leading to loss of gingival tissues and alveolar bone supporting the teeth. Previous studies have explored the role of COX-2 polymorphisms with the risk of periodontitis in different ethnic groups; however, findings are inconsistent. So, we aimed to investigate the association of COX-2 polymorphisms (rs20417, rs689466, and rs5275) in susceptibility to chronic periodontitis (CP) in northern Indian population. Meta-analysis was also carried out to precisely estimate the effect of COX-2 polymorphisms in CP.

MATERIALS AND METHODS

Genotyping of COX-2 polymorphisms was carried out through PCR-RFLP in 200 CP cases and 200 controls. For risk estimation, binary logistic regression was applied using SPSS, version 15.0, while meta-analysis was carried using MIX 2.0 software.

RESULTS

None of the COX-2 polymorphisms independently were associated with the risk of CP. Meta-analysis suggested a significant reduced risk of CP with rs5275+8473 C allele and rs20417 in Chinese population.

CONCLUSIONS

No association was observed in any of the studied COX-2 polymorphisms with CP in North India. But, the study should be replicated in larger sample size to arrive at a definitive conclusion. Meta-analysis suggested a role of rs5275 COX-2 polymorphisms in susceptibility to overall CP, and on ethnic basis, rs20417 showed reduced risk of CP in Chinese population.