Effect of periodontal therapy on insulin resistance in adults with dysglycemia and periodontitis: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aimed to address whether non-surgical periodontal therapy (NSPT) can affect insulin resistance, estimated by the homeostasis model assessment (HOMA), in adults with prediabetes or type 2 diabetes mellitus and periodontitis. MATERIALS AND METHODS: Six electronic databases and the gray literature were systematically searched for interventional studies reporting NSPT effect on insulin resistance. Seven studies met the eligibility criteria to be synthesized in the qualitative analysis, six reporting change in HOMA-IR, three reporting change in HOMA-%S, and two in HOMA-ß. Among them, four were pooled in a meta-analysis of standardized mean difference (SMD) of HOMA-IR; comparing pre- and post-intervention values, three were pooled considering HOMA-%S as outcome, and two studies were summarized considering SMD of HOMA-%S between intervention and control groups. HOMA-ß results were qualitatively synthetized. RESULTS: With low level of certainty, NSPT significantly reduced HOMA-IR, when compared with pre-intervention data (SMD, -0.35, 95% CI -0.63 to 0.07, p=0.02). There were no significant changes in HOMA-%S or in HOMA-ß scores. The level of certainty was very low and moderate, respectively. CONCLUSIONS: Assertions about a causal link between NSPT and insulin resistance are weak and conflicting, although our more robust results point out to the absence of effect. . CLINICAL RELEVANCE: Because further high-quality studies assessing the relationship between periodontitis and insulin resistance are need, the findings of the current systematic review are limited to give recommendations for clinicians. However, while identifying a lack of research in humans with T2D concerning periodontitis and insulin resistance, this study reinforces the need of multicenter well-designed randomized clinical trials.

Clinical efficacy of subgingivally delivered propolis as an adjuvant to nonsurgical periodontal treatment of periodontitis: A systematic review and meta-analysis.

This systematic review and meta-analysis evaluated randomized and nonrandomized studies that assessed the effect of local subgingival propolis as an adjunct to nonsurgical periodontal therapy (NSPT) in the treatment of periodontitis. A detailed search was carried out in Cochrane Library, Embase, LILACS, LIVIVO, PubMed, Scopus, and Web of Science, with no time or language restrictions. A grey literature search was also conducted. The methodology of included studies was evaluated by the Cochrane RoB2 tool. The certainty of each clinical outcome was assessed by the GRADE system. Meta-analyses of mean difference were conducted using the random-effects model, through RevMan 5.4 software. Six studies met the eligibility criteria to be synthesized in the qualitative analysis, and three studies were included in the meta-analysis. The subgingival application of propolis as an adjunct to NSPT improved probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP) in most of the assessed studies. The overall mean difference in PPD reduction was 1.49 mm, 30-45 days after treatment, and 0.8 mm, 90 days after treatment, with very low level of certainty. The overall bias was scored as high risk for all included studies. The adjunctive use of locally delivered propolis associated to NSPT to treat periodontitis may improve periodontal clinical parameters, compared with NSPT alone/placebo. However, the evidence was not strong enough to safely base any clinical recommendation.

Host-derived salivary biomarkers in diagnosing periodontal disease: systematic review and meta-analysis.

AIM: To systematically evaluate the accuracy of host-derived salivary biomarkers in the diagnosis of periodontal disease based on the given sensitivity and specificity information. MATERIALS AND METHODS: Studies were eligible for inclusion if they had compared the diagnostic application of salivary biomarkers with clinical examination of periodontal disease. A detailed search was performed in five databases without restrictions on subject age, chronology, or language. Additionally, a partial grey-literature search was conducted. The revised Quality Assessment of Diagnostic Accuracy Studies tool and Meta-analysis were used to evaluate the selected studies. RESULTS: From the 905 screened studies, four were included in the qualitative and quantitative analysis. One biomarker, macrophage inflammatory protein-1α (MIP-1α), had excellent diagnostic accuracy and two, interleukin-1ß (IL-1ß) and interleukin-6 (IL-6), showed acceptable diagnostic values. However, the only biomarker considered excellent was evaluated in a single study, which may reduce the robustness of the results. CONCLUSION: There is currently limited evidence to confirm the diagnostic capability of salivary biomarkers in the clinical assessment of periodontal disease. Notwithstanding, the summary findings showed the growing importance of salivary biomarker, and can guide larger, well-controlled, diagnostic accuracy studies. Likewise, although not conclusive, MIP-1α, IL-1ß, and IL-6 may be promising biomarkers for future studies.

Investigation of PPARß/δ within Human Dental Pulp Cells: A Preliminary In Vitro Study.

Controlling the inflammatory response to restore tissue homeostasis is a crucial step to maintain tooth vitality after pathogen removal from caries-affected dental tissues. The nuclear peroxisome proliferator-activated receptor beta/delta (PPARß/δ) is a ligand-activated transcription factor with emerging anti-inflammatory roles in many cells and tissues. However, its expression and functions are poorly understood in human dental pulp cells (hDPCs). Thus, this study evaluated PPARß/δ expression and assessed the anti-inflammatory effects evoked by activation of PPARß/δ in lipopolysaccharide- (LPS-) induced hDPCs. Our results showed that hDPCs constitutively expressed PPARß/δ mRNA/protein, and treatment with LPS increased PPARß/δ mRNA expression. The selective PPARß/δ agonist GW0742 significantly decreased inflammation-related mRNA expression in hDPCs (IL6, IL1ß, TNFα, MMP1, and MMP2) and RAW264.7 cells (Il6 and Tnfα). Further, PPARß/δ agonist attenuated MMP2/9 gelatinolytic activity in hDPCs. Previously LPS-conditioned hDPCs increased the migration of RAW264.7 cells through the membrane of a Transwell coculture system. Conversely, pretreatment with GW0742 markedly decreased macrophage recruitment. These findings provide among the first evidence that hDPCs express PPARß/δ. In addition, they suggest that activation of PPARß/δ by GW0742 can attenuate some cellular and molecular in vitro aspects related to the inflammatory process, pointing out to investigate its potential target role in dental pulp inflammation.

Dibutyltin Compounds Effects on PPARγ/RXRα Activity, Adipogenesis, and Inflammation in Mammalians Cells.

Organotins are a group of chemical compounds that have a tin atom covalently bound to one or more organic groups. The best-studied organotin is tributyltin chloride, which is an environmental pollutant and an endocrine disruptor. Tributyltin chloride has been shown to bind to PPARγ/RXRα and induces adipogenesis in different mammalian cells. However, there are few studies with other organotin compounds, such as dibutyltins. The aim of this study was to investigate the effect of dibutyltins diacetate, dichloride, dilaurate, and maleate on the transcriptional activity of the nuclear PPARγ and RXRα receptors, and on adipogenesis and inflammation. Analogous to tributyltin chloride, in reporter gene assay using HeLa cells, we observed that dibutyltins diacetate, dichloride, dilaurate, and maleate are partial agonists of PPARγ. Unlike tributyltin chloride, which is a full agonist of RXRα, dibutyltins dichloride and dilaurate are partial RXRα agonists. Additionally, the introduction of the C285S mutation, which disrupts tributyltin chloride binding to PPARγ, abrogated the dibutyltin agonistic activity. In 3T3-L1 preadipocytes, all dibutyltin induced adipogenesis, although the effect was less pronounced than that of rosiglitazone and tributyltin chloride. This adipogenic effect was confirmed by the expression of adipogenic markers Fabp4, Adipoq, and Glut4. Exposure of 3T3-L1 cells with dibutyltin in the presence of T0070907, a specific PPARγ antagonist, reduced fat accumulation, suggesting that adipogenic effect occurs through PPARγ. Furthermore, dibutyltins dichloride, dilaurate, and maleate inhibited the expression of proinflammatory genes in 3T3-L1 cells, such as Vcam1, Dcn, Fn1, S100a8, and Lgals9. Additionally, in RAW 264.7 macrophages, tributyltin chloride and dibutyltin dilaurate reduced LPS-stimulated TNFα expression. Our findings indicate that dibutyltins diacetate, dichloride, dilaurate, and maleate are PPARγ partial agonists and that dibutyltins dichloride and dilaurate are also partial RXRα agonists. Furthermore, dibutyltins induce adipogenesis in a PPARγ-dependent manner and repress inflammatory genes in 3T3-L1 and RAW 264.7 cells. Although dibutyltins display some partial PPARγ/RXRα agonistic effects, the translation of cell-based results assays into in vivo effects on inflammation and insulin resistance is not entirely known. Nevertheless, further studies are necessary to address their effects in different periods of life and to elucidate the actions of organostanic compounds in whole-body context.

GQ-16, a TZD-Derived Partial PPARγ Agonist, Induces the Expression of Thermogenesis-Related Genes in Brown Fat and Visceral White Fat and Decreases Visceral Adiposity in Obese and Hyperglycemic Mice.

BACKGROUND: Beige adipocytes comprise a unique thermogenic cell type in the white adipose tissue (WAT) of rodents and humans, and play a critical role in energy homeostasis. In this scenario, recruitment of beige cells has been an important focus of interest for the development of novel therapeutic strategies to treat obesity. PPARγ activation by full agonists (thiazolidinediones, TZDs) drives the appearance of beige cells, a process so-called browning of WAT. However, this does not translate into increased energy expenditure, and TZDs are associated with weight gain. Partial PPARγ agonists, on the other hand, do not induce weight gain, but have not been shown to drive WAT browning. The present study was designed to investigate the effects of GQ-16 on BAT and on browning of WAT in obese mice. METHODS: Male Swiss mice with obesity and hyperglycemia induced by high fat diet were treated with vehicle, rosiglitazone (4 mg/kg/d) or the TZD-derived partial PPARγ agonist GQ-16 (40 mg/kg/d) for 14 days. Fasting blood glucose, aspartate aminotransferase, alanine aminotransferase and lipid profile were measured. WAT and brown adipose tissue (BAT) depots were excised for determination of adiposity, relative expression of Ucp-1, Cidea, Prdm16, Cd40 and Tmem26 by RT-qPCR, histological analysis, and UCP-1 protein expression analysis by immunohistochemistry. Liver samples were also removed for histological analysis and determination of hepatic triglyceride content. RESULTS: GQ-16 treatment reduced high fat diet-induced weight gain in mice despite increasing energy intake. This was accompanied by reduced epididymal fat mass, reduced liver triglyceride content, morphological signs of increased BAT activity, increased expression of thermogenesis-related genes in interscapular BAT and epididymal WAT, and increased UCP-1 protein expression in interscapular BAT and in epididymal and inguinal WAT. CONCLUSION: This study suggests for the first time that a partial PPARγ agonist may increase BAT activity and induce the expression of thermogenesis-related genes in visceral WAT. GENERAL SIGNIFICANCE: These findings suggest that PPARγ activity might be modulated by partial agonists to induce WAT browning and treat obesity.