Type-2 diabetes mellitus, metabolic control, serum inflammatory factors, lifestyle, and periodontal status

Porphyromonas gingivalis infection promotes inflammation via inhibition of the AhR signalling pathway in periodontitis

Porphyromonas gingivalis (P. gingivalis) is a key pathogen of chronic periodontitis. Aryl hydrocarbon receptor (AhR) is essential in immune homeostasis via modulation of pro-inflammatory cytokines production and indoleamine 2,3-dioxygenase (IDO). In this study, it is demonstrated that P. gingivalis may regulate AhR signalling in periodontitis, which provides a potential target for further immune regulation studies in periodontitis. Experimental periodontitis was induced in C57BL/6 mice by silk ligature and P. gingivalis oral inoculation. The alveolar bone resorption was examined using Micro-CT. Histological structures were observed and related cytokines involved in AhR signalling pathway were analysed. RAW264.7 cells were pretreated with AhR agonist (FICZ) and antagonist (CH223191) and infected with P. gingivalis subsequently. The levels of IDO, AhR and other related cytokines were measured. To demonstrate IDO activity, the concentrations of tryptophan (Trp) and kynurenine (Kyn) were assessed by HPLC. Histological analysis of periodontitis mice showed distinct alveolar bone resorption and inflammatory cell infiltration. The level of AhR and its downstream target factors were significantly decreased in inflamed gingival tissue. Furthermore, RAW 264.7 cells incubated by P. gingivalis exhibited increased pro-inflammatory cytokines production and decreased AhR, CYP1A1, CYP1B1, and IDO expression. Decreased IDO activity was observed as decreased Kyn/Trp ratio in the supernatant. Moreover, FICZ decreased the pro-inflammatory cytokines levels in P. gingivalis infected cells. It is concluded that P. gingivalis may promote inflammatory responses via inhibiting the AhR signalling pathway in periodontitis.

Adjunctive Er:YAG laser in non-surgical periodontal therapy of patients with inadequately controlled type 2 diabetes mellitus: A split-mouth randomized controlled study

BACKGROUND AND OBJECTIVE

Limited studies are available comparing the outcomes of non-surgical periodontal therapy (NSPT) with or without adjunctive Er:YAG laser (ERL) in patients with type 2 diabetes mellitus (T2DM). This study evaluated the effects of ERL adjunctive NSPT on single-rooted teeth of inadequately controlled T2DM patients with periodontitis.

METHODS

Twenty-two inadequately controlled T2DM participants with periodontitis were recruited. Adopting a double-blinded split-mouth design and under block randomization, we investigated the effects of ERL in calculus removal then degranulation mode, or a sham treatment, adjunct NSPT, which included two visits of full-mouth root surface debridement delivered within 4-10 days, to test or control single-rooted teeth (Wuxi Stomatology Hospital, trial 2017-016). We followed periodontal parameters (plaque %, bleeding on probing [BOP] %, probing pocket depth [PPD], probing attachment level [PAL]) and selected systemic parameters (fasting plasma glucose [FPG], glycosylated hemoglobin [HbA1c%], high sensitivity C-reactive protein) at baseline, one, three, and six months after periodontal treatment.

RESULTS

The study was completed as planned. Periodontal parameters, FPG and HbA1c% of the 22 participants appeared significantly improved at six months (p < 0.001). The 44 ERL treated, compared to 44 sham treated single-rooted teeth exhibited significant improvement in BOP, mean PPD, and mean PAL at various postoperative follow-up time points (effect size ≥0.44; p < 0.001). No adverse event was reported.

CONCLUSION

Periodontal treatment outcomes in the T2DM patients with inadequate glycemic control were better in the single-rooted teeth received ERL adjunct NSPT. Further studies are warranted to confirm the observations reported in this short-term clinical study.

Evaluation of the Genetic Association and Methylation of Immune Response Pathway Genes with the Risk of Chronic Periodontitis in the Uighur Population

Aim: The aim of this study was to explore the possible associations between single nucleotide polymorphisms (SNPs) and DNA methylation levels of seven genes in the inflammatory response pathway with susceptibility to chronic periodontitis (CP) among the Uighur population of the Xinjiang Autonomous Region of China. Methods: A total of 444 eligible subjects (279 CP patients and 165 healthy controls) were enrolled in the study. Genomic DNA was obtained from gingival tissue for genotyping eight SNPs and performing methylation measurements of seven genes. Results: SNP rs2070745 in the formyl peptide receptor 1 (FPR1) gene achieved statistical significance in a standard allelic association analysis for CP (p = 0.02). The frequency of the rs2070745 minor allele G was higher in the cases than in controls (0.367 vs. 0.291). Additionally, rs2070745 was significantly associated with CP under the dominant genetic model (p = 0.03). Using logistic regression analysis, rs2070745 was found to be consistently associated with CP under the additive dominant model, and this association remained significant after covariates were taken into account [odds ratio (OR) = 1.49 (1.09-2.05), p = 0.014; OR = 1.58 (1.04-2.40), p = 0.031, respectively]. No significant gene-gene interactions were identified. Although we did not find a polymorphism in interleukin 6 (IL6) associated with CP in our study, the methylation level of a CpG island region located within the promoter region of IL6 was significantly less in CP patients compared with controls (p < 0.05). Conclusions: The genetic polymorphism rs2070745 in FPR1 and the methylation level of the promoter region of IL6 might be associated with CP in the Uighur population of China.

Sticking for a Cause: The Falciparum Malaria Parasites Cytoadherence Paradigm

After a successful invasion, malaria parasite Plasmodium falciparum extensively remodels the infected erythrocyte cellular architecture, conferring cytoadhesive properties to the infected erythrocytes. Cytoadherence plays a central role in the parasite's immune-escape mechanism, at the same time contributing to the pathogenesis of severe falciparum malaria. In this review, we discuss the cytoadhesive interactions between P. falciparum infected erythrocytes and various host cell types, and how these events are linked to malaria pathogenesis. We also highlight the limitations faced by studies attempting to correlate diversity in parasite ligands and host receptors with the development of severe malaria.