Novel Insight into the Mechanisms of the Bidirectional Relationship between Diabetes and Periodontitis

Association between prediabetes and periodontitis: a meta-analysis of observational studies with multivariate analysis

BACKGROUND

Growing evidence suggests that prediabetes may increase the risk of periodontitis, though the extent of this association remains unclear. To provide a clearer understanding, this meta-analysis focused on observational studies that utilized multivariate analyses to adjust for key confounding factors.

MATERIAL AND METHODS

A comprehensive search of PubMed, Embase, and Web of Science was conducted to identify observational studies assessing the relationship between prediabetes and periodontitis. Only studies that utilized multivariate analyses were included to minimize confounding bias. The quality of the studies was evaluated with the Newcastle-Ottawa Scale (NOS). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model, with heterogeneity assessed by the I² statistic.

RESULTS

Ten observational studies with 38,727 participants were included. Overall, individuals with prediabetes had a significantly higher risk of periodontitis compared to normoglycemic individuals (OR: 1.27, 95% CI: 1.09 to 1.48, p < 0.001) with moderate heterogeneity (I² = 53%). Subgroup analyses revealed a stronger association in studies where the proportion of men was < 45% compared to those ≥ 45% (OR: 1.75 vs. 1.15, p for subgroup difference = 0.01). Studies with lower quality (NOS score = 7) showed a stronger association compared to higher-quality studies (NOS score = 8 or 9, p for subgroup difference = 0.003).

CONCLUSION

This meta-analysis found that prediabetes may be independently associated with an increased risk of periodontitis. Further research is needed to explore the mechanisms underlying this association and potential sex-specific effects.

Mitochondrial dysfunction as a key player in aggravating periodontitis among diabetic patients: review of the current scope of knowledge

Periodontitis is a prevalent inflammatory disease that leads to significant periodontal tissue destruction and compromised dental health, with its severity exacerbated in individuals with Diabetes Mellitus (DM). This review explores the complex relationship between mitochondrial dysfunction and periodontitis in diabetic patients. Recent studies indicate that the excessive production of reactive oxygen species (ROS), primarily generated by dysfunctional mitochondrial electron transport chain (ETC) complexes, contributes to oxidative stress (OS) and subsequent periodontal tissue damage. The interplay between impaired mitochondrial biogenesis, apoptosis of periodontal cells, and ROS accumulation highlights a critical area of concern in understanding the pathophysiology of diabetic periodontitis. Furthermore, altered glycemic control due to inflammatory processes associated with periodontitis may perpetuate a cyclical detriment to oral and systemic health. This review aims to highlight the mechanistic roles of mitochondrial dysfunction in the aggravation of periodontitis among diabetic patients, emphasizing further research to identify potential therapeutic targets and improve treatment efficacy for this dual pathology.

Diabetic Retinopathy and Periodontitis: Implications from a Systematic Review and Meta-Analysis

BACKGROUND

Diabetes mellitus, a chronic metabolic disorder affecting millions worldwide, is associated with microvascular complications, including diabetic retinopathy (DR) and periodontitis. Understanding their interrelationship is crucial for comprehensive patient care.

OBJECTIVE

This systematic review and meta-analysis aim to investigate the association between DR and periodontitis in patients with Type 1 and Type 2 diabetes.

METHODOLOGY

Using the PECO framework, we searched PubMed/MEDLINE, Scopus, EMBASE, Google Scholar, and Web of Science databases (Inception to April 2023) for studies on the association between DR and periodontitis. Ten studies (n = 1828 participants), including observational and cross-sectional studies, met the inclusion criteria. We conducted qualitative synthesis, risk of bias analysis using the ROBINS-E tool, Grading of Recommendations, Assessment, Development, and Evaluations assessment (GRADE), and random-effects meta-analysis.

RESULTS

Eight studies found a significant association between severe periodontitis (pocket depth ≥5 mm) and DR, while two found no association. Meta-analysis of 843 participants showed diabetics with periodontitis had 4.48 times higher odds (95% confidence interval: 1.67-12.07, P = .003) of developing retinopathy compared to diabetics without periodontitis. High heterogeneity was observed (I2 = 86%). Subgroup analysis by diabetes type showed no significant difference. The overall GRADE level of evidence was very low.

CONCLUSION

While most included studies suggest an association between severe periodontitis and increased DR risk, the overall certainty of evidence is low. These findings highlight the potential importance of periodontal health in diabetic patients. High-quality longitudinal studies with adequate control of confounders are required to determine if periodontitis contributes to the progression of DR or if the conditions are merely coincidentally related.

The Nexus Between Traditional Chinese Medicine and Immunoporosis: Implications in the Treatment and Management of Osteoporosis

Osteoporosis (OP) is a globally prevalent bone disease characterized by reduced bone mass and heightened fracture risk, posing a significant health and economic challenge to aging societies worldwide. Osteoimmunology-an emerging field of study-investigates the intricate relationship between the skeletal and the immune systems, providing insights into the immune system's impact on bone health and disease progression. Recent research has demonstrated the essential roles played by various immune cells (T cells, B cells, macrophages, dendritic cells, mast cells, granulocytes, and innate lymphoid cells) in regulating bone metabolism, homeostasis, formation, and remodeling through interactions with osteoclasts (OC) and osteoblasts (OB). These findings underscore that osteoimmunology provides an essential theoretical framework for understanding the pathogenesis of various skeletal disorders, including OP. Traditional Chinese medicine (TCM) and its active ingredients have significant clinical value in OP treatment. Unfortunately, despite their striking multieffect pathways in the pharmacological field, current research has not yet summarized them in a comprehensive and detailed manner with respect to their interventional roles in immune bone diseases, especially OP. Consequently, this review addresses recent studies on the mechanisms by which immune cells and their communication molecules contribute to OP development. Additionally, it explores the potential therapeutic benefits of TCM and its active components in treating OP from the perspective of osteoimmunology. The objective is to provide a comprehensive framework that enhances the understanding of the therapeutic mechanisms of TCM in treating immune-related bone diseases and to facilitate the development of novel therapeutic strategies.

Association between adjustable dietary factors and periodontitis: NHANES 2009-2014 and Mendelian randomization

BACKGROUND

Periodontitis is the major cause of tooth loss in adults and one of the most common non-communicable diseases. Clinically, periodontitis impairs oral health and associated with various systemic diseases. Maintaining a healthy diet is considered risk reduction of periodontitis. To explore the causal effect between dietary data and periodontitis by Mendelian randomization (MR) analyses.

METHODS

A total of 11,704 participants and 21 dietary variables from the NHANES were in random forest to rank the importance in predicting periodontitis. Data were from the genome wide association studies (GWASs) database to estimate causal relationships between diet data and periodontitis. Two-sample MR analyses were conducted by using the inverse-variance weighted (IVW) method.

RESULTS

The MR showed alcohol consumption and sugars intake increased the risk of chronic periodontitis with odds ratio (OR) 2.768 (95% CI: 1.03e + 00-7.42e + 00) and 2.123 (95% CI: 1.06e + 00-4.26e + 00) respectively. Vitamins and minerals, including folic acid and folate, magnesium, vitamin A, vitamin E, vitamin C, calcium, vitamin D and zinc, were not causally associated with chronic periodontitis. Alcohol consumption greater than 2.5 drinks per day and sugar intake more than 4.88 g increased the risk of periodontitis, with a calculated relative risk of 1.33 and 1.61, respectively.

CONCLUSION

It is suggested to drink alcohol less than 2.5 drinks/day and consume sugar less than 4.88 g/day to avoid alcohol and sugar consumption promoting the development of periodontitis. Establishing a dietary pattern conducive to periodontal health may be the focus of further clinical research.

The need for effective interprofessional collaboration between nutrition and dentistry

There are bidirectional relationships between diet and nutrition, systemic health and oral health. Diet and nutrition are fundamental to the prevention and management of chronic diseases. Systemic health can impact oral health. And oral health can influence diet and nutrition. The 2020 Surgeon General's Report "Oral Health in America" stated that nutrition is an integral factor in the development of oral disease and health overall. Within the medical model, Registered Dietitians have been impactful members of a multidisciplinary team by providing medical nutrition therapy and nutritional counseling to reduce the development and management of chronic diseases like obesity, diabetes and cardiovascular disease. Despite the well-established collaboration and the role nutrition plays in health outcomes, there is limited documented collaboration between nutrition and dentistry. The purpose of this paper is to review the current evidence of nutritional counseling in oral health settings compared to the medical model, identify specific challenges, and suggest possible next steps for collaboration. The intended outcome of this paper will be to provide the reader with insight about the need to integrate nutrition into both oral health education and clinical practice to address prevalent chronic diseases and increase health equity for those at high risk.

Identification of Gingival Inflammation Surface Image Features Using Intraoral Scanning and Deep Learning

INTRODUCTION AND AIM

The assessment of gingival inflammation surface features mainly depends on subjective judgment and lacks quantifiable and reproducible indicators. Therefore, it is a need to acquire objective identification information for accurate monitoring and diagnosis of gingival inflammation. This study aims to develop an automated method combining intraoral scanning (IOS) and deep learning algorithms to identify the surface features of gingival inflammation and evaluate its accuracy and correlation with clinical indicators.

METHODS

The study included the periodontal probing data and intraoral scan images of 120 patients with periodontitis. The deep learning model GC-U-Net was used to automatically segment and identify the gingival inflammation regions. The performance of the model was evaluated by the Dice coefficient (Dice), intersection over union (IoU), and pixel accuracy (PA), and the correlation between the identification performance and the periodontal examination index was analysed.

RESULTS

The GC-U-Net model showed high recognition accuracy, with a Dice of 77.8%, an IoU of 65.4%, and a PA of 93.7%. This model demonstrated a strong positive correlation with the sulcus bleeding index (SBI; r = 0.836, P < .001), a moderately strong positive correlation with the bleeding index (BI; r = 0.618, P < .001), and a negative correlation with the probe depth (PD; r = - 0.425, P < .001).

CONCLUSION

The study has successfully developed an automatic identification method for surface characteristics of gingival inflammation based on deep learning and IOS technology, providing a standardised and automated auxiliary tool for clinical gingival inflammation examination with high accuracy and significant correlation with clinical indicators.

CLINICAL RELEVANCE

This method can reduce subjective judgment in the clinical assessment of gingival inflammation, improve the consistency and reliability of identification, and play an important auxiliary role in clinical diagnosis and treatment planning.

Immunopathogenesis and immunotherapy of diabetes-associated periodontitis

OBJECTIVES

This paper aims to review the immunopathogenesis of Diabetes-associated periodontitis (DPD) and to propose a description of the research progress of drugs with potential clinical value from an immunotherapeutic perspective.

MATERIALS AND METHODS

A comprehensive literature search was conducted in PubMed, MEDLINE, Embase, Web of Science, Scopus and the Cochrane Library. Inclusion criteria were studies on the association between diabetes and periodontitis using the Boolean operator "AND" for association between diabetes and periodontitis, with no time or language restrictions. Search terms included diabetes mellitus, periodontitis, immunopathogenesis, specific immunity, non-specific immunity, flora, estrogen, pharmacological treatment, immunotherapy.

RESULTS

Alterations in the subgingival flora environment in a hyperglycemic environment elicit an immune response. Overactivity/suppression of nonspecific immune cells and impaired cellular defenses trigger specific immune responses. Epigenetics as well as female hormones also play a role. There is already a small amount of clinical evidence for the role of metronidazole, subantimicrobial doses of doxycycline, minocycline hydrochloride, and metformin in the treatment of DPD. Some preclinical studies have also accumulated experimental evidence for the improved effects of vitamin D3 and other drugs on DPD.

CONCLUSIONS

The development of diabetic periodontitis is immunologically linked to a state of immune imbalance and therefore holds great promise for the use of immunotherapeutic drugs.

CLINICAL SIGNIFICANCE

Immunotherapy with drugs along with periodontal nonsurgical treatment could provide ideas for DPD treatment based on the immunopathogenesis of DPD.

Oral Pathogens' Substantial Burden on Cancer, Cardiovascular Diseases, Alzheimer's, Diabetes, and Other Systemic Diseases: A Public Health Crisis-A Comprehensive Review

This review synthesizes the findings from 252 studies to explore the relationship between the oral pathogens associated with periodontitis, dental caries, and systemic diseases. Individuals with oral diseases, such as periodontitis, are between 1.7 and 7.5 times (average 3.3 times) more likely to develop systemic diseases or suffer adverse pregnancy outcomes, underscoring the critical connection between dental and overall health. Oral conditions such as periodontitis and dental caries represent a significant health burden, affecting 26-47% of Americans. The most important oral pathogens, ranked by publication frequency, include the herpes virus, C. albicans, S. mutans, P. gingivalis, F. nucleatum, A. actinomycetemcomitans, P. intermedia, T. denticola, and T. forsythia. The systemic diseases and disorders linked to oral infections, ranked similarly, include cancer, respiratory, liver, bowel, fever, kidney, complications in pregnancy, cardiovascular bacteremia, diabetes, arthritis, autoimmune, bladder, dementia, lupus, and Alzheimer's diseases. Evidence supports the efficacy of dental and periodontal treatments in eliminating oral infections and reducing the severity of systemic diseases. The substantial burden that oral pathogens have on cancer, cardiovascular diseases, Alzheimer's, diabetes, and other systemic diseases poses a significant public health crisis.

Exploring the Impact of Biological Agents on Protecting Against Experimental Periodontitis: A Systematic Review of Animal-Based Studies

Aim: This systematic review was aimed at addressing the focused question: What is the protective potential of biological agents against alveolar bone resorption during the progression of experimental periodontitis (EP)? Material and Methods: The study protocol was registered in the Open Science Framework database (doi:10.17605/OSF.IO/3P2HY). A comprehensive literature search was conducted across PubMed, Web of Science, Cochrane Library, Scopus, and Embase databases up to December 2023. Inclusion criteria consisted of preclinical studies in animal models of EP that examined the effects of biological agents on preventing periodontal bone loss and reducing tissue inflammation. Studies were excluded if they (i) used non-EP animal models; (ii) focused on antimicrobial agents; (iii) centered on prebiotics or probiotics; (iv) evaluated compounds not classified as biologicals; or (v) included randomized clinical trials, clinical studies, or reviews. Eligibility was determined based on the PI/ECOs framework, and study quality was assessed using the SYRCLE risk-of-bias tool. Results: After screening an initial pool of 5236 records from databases, registries, and hand searches, 39 studies met the inclusion criteria. A total of 23 biological agents were evaluated across these studies. The majority of studies employed the ligature-induced model of EP to test the effectiveness of biologicals as preventive or therapeutic interventions. The dosage of biological agents and the duration of disease induction varied depending on the EP model. In all studies, the main outcome-alveolar bone loss, a hallmark of EP-was significantly inhibited by biological agents, which also reduced proinflammatory mediators when compared to untreated controls. A key strength of this review is the high number of studies included, most of which were classified as having low risk of bias. However, a notable limitation is the absence of a meta-analysis, the short follow-up periods in the included studies, and the heterogeneity among the compound dosages and route of administration. Conclusion: This systematic review demonstrates that biological agents are effective in reducing bone loss and mitigating inflammation during EP progression. Randomized clinical trials are needed to confirm these findings in human populations.

Periodontal bacteria influence systemic diseases through the gut microbiota

Many systemic diseases, including Alzheimer disease (AD), diabetes mellitus (DM) and cardiovascular disease, are associated with microbiota dysbiosis. The oral and intestinal microbiota are directly connected anatomically, and communicate with each other through the oral-gut microbiome axis to establish and maintain host microbial homeostasis. In addition to directly, periodontal bacteria may also be indirectly involved in the regulation of systemic health and disease through the disturbed gut. This paper provides evidence for the role of periodontal bacteria in systemic diseases via the oral-gut axis and the far-reaching implications of maintaining periodontal health in reducing the risk of many intestinal and parenteral diseases. This may provide insight into the underlying pathogenesis of many systemic diseases and the search for new preventive and therapeutic strategies.

Evaluation of salivary interleukin‐17 and developmental endothelial locus‐1 in patients with periodontitis with and without type 2 diabetes mellitus

Background

Bidirectional positive relationship between periodontitis and type 2 diabetes mellitus (T2DM) has been recognized, interleukin 17 (IL‐17) and developmental endothelial locus‐1 (Del‐1) are proposed to play roles in periodontitis and T2DM. This study aims to investigate the association of IL‐17 and Del‐1 in patients with periodontitis with and without T2DM by measuring their salivary levels.

Methods

A total of 80 participants were enrolled in a cross‐sectional study and divided into healthy (H, n = 27), periodontitis (P, n = 29) and periodontitis with diabetes (PDM, n = 24) groups based on their periodontal and diabetic examination results. Periodontal parameters (plaque index [PI], bleeding on probing [BOP], probing depth [PD], and clinical attachment level [CAL]) as well as diabetic parameters (fasting plasma glucose [FG] and glycated hemoglobin [HbA1c]) were documented and unstimulated saliva was collected. Salivary IL‐1β, active‐matrix metalloproteinase‐8 (aMMP‐8), tumor necrosis factor‐α (TNF‐α), IL‐6, IL‐8, IL‐17, and Del‐1 were determined through enzyme‐linked immunosorbent assay (ELISA) and their relationships with periodontal and diabetic parameters were examined.

Results

The periodontitis and periodontitis with diabetes groups showed significantly higher levels of IL‐17 and lower levels of Del‐1 compared with healthy group. The periodontitis with diabetes group exhibited higher levels of IL‐17 and lower levels of Del‐1 compared with the periodontitis group. After correlation analysis, there were significant correlations between salivary IL‐17 and Del‐1 and clinical parameters, IL‐17 and Del‐1 were correlated with PD (r = 0.36, ‐0.39, p < 0.01), CAL (r = 0.40, ‐0.42, p < 0.01) and BOP (r = 0.35, ‐0.37, p < 0.01), they were correlated with FG (r = 0.26, ‐0.25, p < 0.05) and HbA1c (r = 0.28, ‐0.40, p < 0.05). Positive relationships were observed between IL‐17 and IL‐1β and between IL‐17 and aMMP‐8 (r = 0.80, 0.77, p < 0.01), while Del‐1 exhibited negative correlations with IL‐1β and aMMP‐8 (r = 0.59, 0.69 p < 0.01). Comparison between IL‐17 and Del‐1 confirmed an inverse relationship (r = ‐0.71, p < 0.01). Salivary Del‐1 levels in the older group were lower compared with young group across the H, P and PDM groups, although these differences were not statistically significant (p > 0.05).

Conclusions

Salivary IL‐17 and Del‐1 levels in the periodontitis with diabetes group showed significant changes compared with the periodontitis group, they exhibited an inverse relationship and were both correlated with periodontal parameters (PD, CAL, and BOP) and diabetic parameters (FG and HbA1c).

Plain Language Summary

Periodontitis and type 2 diabetes mellitus (T2DM) are two common diseases all over the world, some inflammatory mediators (interleukin 17 [IL‐17] and developmental endothelial locus‐1 [Del‐1]) regulate neutrophil production, recruitment and clearance when the body becomes infected and believed to be involved in the progress of diseases of periodontitis and diabetes. In this study, we enrolled healthy subjects, patients with periodontitis, patients with periodontitis and diabetes. We performed dental examinations and evaluated their blood glucose levels, collected their saliva, and detected IL‐17 and Del‐1 levels in their saliva. We found both patients with periodontitis and patients with periodontitis and diabetes showed higher IL‐17 levels and lower Del‐1 levels compared with healthy subjects. Patients with periodontitis and diabetes showed higher IL‐17 levels and lower Del‐1 levels compared with patients with periodontitis. Salivary IL‐17 and Del‐1 levels were both correlated with dental examination results and blood glucose levels, and salivary IL‐17 and Del‐1 displayed an inverse relationship.

Link between periodontitis and diabetic retinopathy: Inflammatory pathways and clinical implications

The bidirectional relationship between periodontitis and type 2 diabetes mellitus has been well-established. However, the underlying molecular mechanisms remain unclear. Diabetic retinopathy (DR) is an important complication of diabetes, but there are few studies on the relationship between DR and periodontitis, especially on the intrinsic inflammatory pathway mechanism. This article reviews the latest clinical data on how diabetes promotes susceptibility to periodontitis from the epidemiological and molecular perspectives, with a special focus on the key roles of systemic inflammation and endothelial dysfunction in the interplay between DR and periodontitis. Comprehension of the intertwined pathogenesis of DR and periodontitis can better guide the development of comprehensive management strategies for glycemic control and periodontal health, with the aim of mitigating the progression of DR and enhancing overall well-being.

Lysosomal dysfunction-derived autophagy impairment of gingival epithelial cells in diabetes-associated periodontitis with altered protein acetylation

Diabetes-associated periodontitis (DP) presents severe inflammation and resistance to periodontal conventional treatment, presenting a significant challenge in clinical management. In this study, we investigated the underlying mechanism driving the hyperinflammatory response in gingival epithelial cells (GECs) of DP patients. Our findings indicate that lysosomal dysfunction under high glucose conditions leads to the blockage of autophagy flux, exacerbating inflammatory response in GECs. Single-cell RNA sequencing and immunohistochemistry analyses of clinical gingival epithelia revealed dysregulation in the lysosome pathway characterized by reduced levels of lysosome-associated membrane glycoprotein 2 (LAMP2) and V-type proton ATPase 16 kDa proteolipid subunit c (ATP6V0C) in subjects with DP. In vitro stimulation of human gingival epithelial cells (HGECs) with a hyperglycemic microenvironment showed elevated release of proinflammatory cytokines, compromised lysosomal acidity and blocked autophagy. Moreover, HGECs with deficiency in ATP6V0C demonstrated impaired autophagy and heightened inflammatory response, mirroring the effects of high glucose stimulation. Proteomic analysis of acetylation modifications identified altered acetylation levels in 28 autophagy-lysosome pathway-related proteins and 37 sites in HGECs subjected to high glucose stimulation or siATP6V0C. Overall, our finding highlights the pivotal role of lysosome impairment in autophagy obstruction in DP and suggests a potential impact of altered acetylation of relevant proteins on the interplay between lysosome dysfunction and autophagy blockage. These insights may pave the way for the development of effective therapeutic strategies against DP.

Melatonin supports nonsurgical periodontal treatment in patients with Type 2 diabetes mellitus and periodontitis: A randomized clinical trial

BACKGROUND

Diabetes mellitus (DM)-associated hyperinflammatory host response significantly provokes periodontal tissue destruction. In this context, the support of nonsurgical periodontal therapy in diabetics with host modulation agents is a current field of study. This clinical study aims to investigate the clinical efficacy of melatonin supplementation and discuss its possible biological mechanisms in nonsurgical periodontal treatment in patients with DM and periodontitis through some fundamental markers.

METHODS

In this randomized controlled and single-blind study, 27 of 55 diabetic patients with periodontitis (stage III/IV and grade C) underwent full-mouth scaling and root planing (fmSRP) alone and 28 patients underwent melatonin administration (6 mg daily, 30 days) in addition to fmSRP (full-mouth scaling and root planing plus melatonin, fmSRP-mel). The potential therapeutic contribution of melatonin was evaluated clinically and biochemically (gingival crevicular fluid RANKL, OPG, MMP-8, and serum IL-1β levels) at 3rd and 6th months.

RESULTS

Melatonin (tablet, 6 mg daily, 30 days) did not cause any local or systemic side effects. fmSRP alone resulted in significant reduction in serum IL-1β levels, pocket depths, gingival inflammation, and gingival crevicular fluid RANKL and MMP-8 levels (p < 0.05). Moreover, melatonin supplementation resulted in a more significant decrease in bleeding and pocket depth scores at probing, especially at 3 months (p < 0.05). Furthermore, RANKL and MMP-8 levels were significantly lower at 3 months and IL-1β levels at 6 months compared to the control group (p < 0.05). However, OPG levels were not affected significantly by the treatments (p > 0.05).

CONCLUSION

Melatonin, as a host modulation agent, significantly increases the clinical efficacy of fmSRP. The reduction in periodontal inflammation and pocket depths may be a result of marked suppression of RANKL-associated osteoclastogenesis and extracellular matrix damage by melatonin.

Lipocalin-2 as a fundamental protein in type 2 diabetes and periodontitis in mice

BACKGROUND

Lipocalin-2 (LCN-2) is an osteokine that suppresses appetite, stimulates insulin secretion, regulates bone remodeling, and is induced by proinflammatory cytokines. The aim of this work was to investigate the participation of LCN-2 in periodontitis associated with type 2 diabetes (T2D) by evaluating alveolar bone loss, glycemic control, inflammation, and femur fragility.

METHODS

A murine model of periodontitis with T2D and elevated LCN-2 concentration was used. Functional LCN-2 inhibition was achieved using an anti-LCN-2 polyclonal antibody, and isotype immunoglobulin G was used as a control. The alveolar bone and femur were evaluated by micro-CT. Glucose metabolism was determined. Tumor necrosis factor (TNF-α) and receptor activator of nuclear factor kappa-B ligand (RANKL) levels in alveolar bone lysates were quantified using ELISA, and serum cytokines were quantified using flow cytometry. A three-point bending test was performed in the femur, and RANKL levels were measured in femur lysates using ELISA.

RESULTS

Functional inhibition of LCN-2 in T2D-periodontitis mice decreased alveolar bone loss in buccal and palatal surfaces and preserved the microarchitecture of the remaining bone, decreased TNF-α and RANKL in alveolar bone, reduced hyperglycemia, glucose intolerance, and insulin resistance, and increased insulin production through improving the functionality of pancreatic β cells. Furthermore, this inhibition increased serum free-glycerol levels, decreased serum interleukin (IL)-6, increased serum IL-4, and reduced femur fragility and RANKL expression in the femur.

CONCLUSIONS

LCN-2 participates in periodontitis associated with T2D. Inhibiting its function in mice with T2D and periodontitis improves pancreatic β-cell function, and glucose metabolism and decreases inflammatory cytokines and bone-RANKL levels, which results in the preservation of femoral and alveolar bone microarchitecture.

PLAIN LANGUAGE SUMMARY

In this study, we explored the role of a bone protein known as lipocalin-2 (LCN-2) in the connection between periodontitis and type 2 diabetes (T2D). Periodontitis is a destructive gum and alveolar bone disease. LCN-2 levels are increased in both T2D and periodontitis. Using a mouse model of T2D with periodontitis, we examined how blocking LCN-2 function affected various aspects of these two diseases. We found that this inhibition led to significant improvements. First, it reduced alveolar bone loss and preserved bone structure by decreasing local inflammation and bone resorption. Second, it improved glucose and lipid metabolism, leading to better blood-sugar control and decreased insulin resistance. Blocking the functions of LCN-2 also decreased systemic inflammation throughout the body and strengthened bone integrity. Overall, our results suggest that LCN-2 plays a crucial role in the periodontitis associated with T2D. By inhibiting LCN-2 function, we were able to improve pancreatic function, improve glucose metabolism, reduce inflammation, and enhance bone health. Targeting LCN-2 could be a promising strategy for the harmful effects of T2D and periodontitis.

Periodontal disease: A silent factor in the development and progression of diabetic retinopathy

The global increase in the prevalence of type 2 diabetes mellitus (T2DM) and its complications presents significant challenges to public health. Recently, per-iodontal disease (PD) was recognized as a factor that is likely to influence the progression of T2DM and its complications due to its potential to exacerbate systemic inflammation and oxidative stress. In this editorial, we comment on the article published by Thazhe Poyil et al in the very recent issue of the World Journal of Diabetes in 2024, which investigated the correlation between PD and diabetic retinopathy (DR) in T2DM patients, with emphasis on the association between periodontal swollen surface area, glycated hemoglobin (HbA1c), interleukin-6 (IL-6), and lipoprotein (a). The findings by Thazhe Poyil et al are significant as they demonstrate a strong link between PD and DR in T2DM patients. This correlation highlights the importance of addressing periodontal health in diabetes management to potentially reduce the risk and severity of DR, a complication of diabetes. The integration of periodontal evaluation and treatment into diabetes care protocols may lead to improved glycemic control and better overall outcomes for T2DM patients . A few studies have established an interconnection between PD and diabetic complication, specifically DR, in T2DM patients, which we aim to highlight in this editorial. Emphasis was placed on the different mechanisms that suggest a bidirectional relationship between PD and T2DM, where the presence of periodontal inflammation negatively influenced glycemic control and contributed to the development and progression of DR through shared inflammatory and vascular mechanisms. This article highlights the importance of collaboration amongst diabetes specialists, ophthalmologists, periodontists, and public health professionals to advance the prevention, early detection, and treatment of PD and DR. This will improve the health and quality of life of T2DM patients. Moreover, the editorial highlights the need for further research on the specific molecular and immunological mechanisms that underlie the link between periodontitis and DR, with identification of common inflammatory biomarkers and signaling pathways. This is expected to facilitate effective direction of therapeutic objectives, thereby improving the management of diabetes and its complications through integrated care that incorporates oral health.

The oral organ: A new vision of the mouth as a whole for a gerophysiological approach to healthy aging

This article brings a new perspective on oral physiology by presenting the oral organ as an integrated entity within the entire organism and its surrounding environment. Rather than considering the mouth solely as a collection of discrete functions, this novel approach emphasizes its role as a dynamic interphase, supporting interactions between the body and external factors. As a resilient ecosystem, the equilibrium of mouth ecological niches is the result of a large number of interconnected factors including the heterogeneity of different oral structures, diversity of resources, external and internal pressures and biological actors. The manuscript seeks to deepen the understanding of age-related changes within the oral cavity and throughout the organism, aligning with the evolving field of gerophysiology. The strategic position and fundamental function of the mouth make it an invaluable target for early prevention, diagnosis, treatment, and even reversal of aging effects throughout the entire organism. Recognizing the oral cavity capacity for sensory perception, element capture and information processing underscores its vital role in continuous health monitoring. Overall, this integrated understanding of the oral physiology aims at advancing comprehensive approaches to the oral healthcare and promoting broader awareness of its implications on the overall well-being.

Correlation Between Gut Microbiota Composition and Serum Interleukin 17 (IL-17) in Mice With Type 2 Diabetes and Experimental Periodontitis

Objective To preliminarily explore the composition characteristics of gut microbiota in mice with type 2 diabetes mellitus (T2DM) and experimental periodontitis, and their correlation with serum IL-17 levels, aiming to provide new insights and evidence for related experimental studies. Methods A total of 42 SPF-grade C57BL/6J mice were randomly selected, with 24 used for T2DM modeling. Successfully modeled T2DM mice were divided into the T2DM group (ND group, n=8) and T2DM with experimental periodontitis group (PD group, n=8). Non-T2DM mice were divided into the blank control group (NC group, n=8) and the experimental periodontitis group (NP group, n=8). After modeling, body weight and fasting plasma glucose (FPG) were measured weekly. Each group of mice underwent an oral glucose tolerance test (OGTT) and an insulin tolerance test (ITT). Six weeks after modeling experimental periodontitis, serum IL-17 levels were measured using ELISA, intestinal inflammation was assessed using HE staining, and gut microbiota composition in cecal contents was analyzed by 16S rRNA sequencing to determine its correlation with serum IL-17 levels. Results FPG in the PD group was higher than in the ND group, with a statistically significant difference in the 12th week (p<0.05). The glucose tolerance level in the PD group was lower than in the ND group (p<0.01). Compared with the NC group, other groups showed varying degrees of inflammatory cell infiltration in the intestinal mucosa, and serum IL-17 levels were lower in both the ND and PD groups compared to the NC group (p<0.01), with the PD group also lower than the NP group (p<0.01). The Shannon and Pielou-e indices of gut microbiota in the PD group were significantly lower than those in the NP group (p<0.05). In terms of microbiota composition, Firmicutes were increased in both the ND and PD groups compared to the NC and NP groups (p<0.05), while Bacteroidetes were decreased (p<0.05). Proteobacteria were increased in the PD group compared to the ND group (p<0.05). The abundance of Bacteroidetes and the Bacteroidetes/Firmicutes ratio was moderately positively correlated with serum IL-17 levels (p<0.01) and moderately negatively correlated with blood glucose levels (p<0.01); serum IL-17 levels were strongly negatively correlated with blood glucose levels (p<0.01). Conclusion Comorbidity of experimental periodontitis and T2DM may exacerbate glucose metabolism impairment in T2DM mice by increasing the abundance of Proteobacteria and intestinal mucosal damage. Serum IL-17 levels may serve as an indicator of gut microbiota dysbiosis in T2DM mice with experimental periodontitis.

Type 2 diabetes aggravates periodontitis-induced pathological changes in the dental pulp

OBJECTIVES

The inner mechanism of how diabetes affects dental pulp of patients with periodontitis has seldom been reported. We collected clinical samples and explored the influence of diabetes and periodontitis on the pathological change of dental pulp.

METHODS

Dental pulp from healthy individuals and patients with periodontitis with or without diabetes were collected based on strict inclusion and exclusion criteria. Dental pulp was morphologically observed; advanced glycation end products (AGEs) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX1) were examined. Oxidative stress (OS), inflammatory indices, and apoptotic levels were assessed.

RESULTS

Morphologically, fibrous structure in the dental pulp of patients with diabetic periodontitis (DP) group was sparse and disordered, and the blood vessel wall was thickened. Diabetes related indexes as AGEs and LOX1 were upregulated. Superoxide dismutase 2 expression was decreased, and OS level was increased. Matrix metalloproteinase 3 and other relevant proinflammatory cytokines levels were increased. The elevated OS and inflammation contributed to upregulation of apoptotic levels in DP group.

CONCLUSIONS

Diabetes aggravates the pathological changes in the dental pulp of periodontitis patients possibly due to upregulated AGEs and LOX1. Our results highlight the importance of early oral intervention in patients with DP.

Mycobacterium tuberculosis : a new hitchhiker in the etiopathogenesis of periodontitis

Periodontitis, a chronic inflammatory disease of the gums affects both the ligament and alveolar bone. A severe form of periodontal disease affects a strikingly high number of one billion adults globally. The disease permutes both the soft and hard tissues of the oral cavity leading to localized and systemic diseases. Periodontitis has a deleterious impact on systemic health causing diabetes, cardiovascular diseases (CVD), and other disease. The cause of the enhanced inflammatory process is due to dysbiosis and an unregulated immune response. Innate immune response and T cells trigger uninhibited cytokine release causing an unwarranted inflammatory response. The RANK- RANKL interaction between osteoblasts, immune cells, and progenitor osteoclasts results in the maturation of osteoclasts, which promote bone resorption. It is well established that dysbiosis of the oral cavity has been implicated in periodontitis. But emerging reports suggest that the pulmonary pathogen, Mycobacterium tuberculosis (Mtb), causes extrapulmonary diseases such as periodontitis. Many clinical case reports advocate the involvement of Mtb in periodontitis, which poses a threat with the surge of tuberculosis in HIV and other immunocompromised individuals. Fostering a better understanding of the mechanism, causative agents and control on inflammatory response is imperative in the prevention and treatment of periodontitis.

Effects of Oleanolic Acid Derived from Wine Pomace on Periodontopathic Bacterial Growth in Healthy Individuals: A Randomized Placebo-Controlled Study

Periodontal disease is caused by oral pathogenic bacteria and is associated with systemic disease and frailty. Therefore, its prevention is crucial in extending healthy life expectancy. This study aimed to evaluate the effect of orally administered oleanolic acid, extracted from wine pomace, on periodontopathic bacterial growth in healthy individuals. In this randomized, placebo-controlled, double-blind, parallel-group comparison study, 84 healthy adults were assigned to a placebo (n = 29), low-dose (n = 29, 9 mg oleanolic acid), or high-dose (n = 26, 27 mg oleanolic acid) groups. The number of oral bacteria in their saliva, collected before and 5 h after administration, was determined using the polymerase chain reaction-invader technique. The proportion of periodontopathic bacteria among the total oral bacteria in the saliva was calculated. Oleanolic acid significantly decreased the proportion of Porphyromonas gingivalis among the total oral bacteria in a dose-dependent manner (p = 0.005 (low-dose) and p = 0.003 (high-dose) vs. placebo, Williams' test). Moreover, high-dose oleanolic acid decreased the proportion of Tannerella forsythia (p = 0.064 vs. placebo, Williams' test). Periodontopathic bacteria are closely associated with the development and progression of periodontal disease; thus, the continuous daily intake of oleanolic acid derived from pomace may be helpful in maintaining a healthy oral microbiome by controlling the proportion of periodontopathic bacteria.

Dental Stem Cells and Lipopolysaccharides: A Concise Review

Dental tissue stem cells (DTSCs) are well known for their multipotent capacity and regenerative potential. They also play an important role in the immune response of inflammatory processes derived from caries lesions, periodontitis, and gingivitis. These oral diseases are triggered by toxins known as lipopolysaccharides (LPS) produced by gram-negative bacteria. LPS present molecular patterns associated with pathogens and are recognized by Toll-like receptors (TLRs) in dental stem cells. In this review, we describe the effect of LPS on the biological behavior of DTSCs. We also focus on the molecular sensors, signaling pathways, and emerging players participating in the interaction of DTSCs with lipopolysaccharides. Although the scientific advances generated provide an understanding of the immunomodulatory potential of DTSCs, there are still new reflections to explore with regard to their clinical application in the treatment of oral inflammatory diseases.

Functional profile of oral plaque microbiome: Further insight into the bidirectional relationship between type 2 diabetes and periodontitis

Increasing evidence support the association between the oral microbiome and human systemic diseases. This association may be attributed to the ability of many oral microbes to influence the inflammatory microenvironment. Herein, we focused our attention on the bidirectional relationship between periodontitis and type 2 diabetes using high-resolution whole metagenomic shotgun analysis to explore the composition and functional profile of the subgingival microbiome in diabetics and non-diabetics subjects with different periodontal conditions. In the present study, the abundance of metabolic pathways encoded by oral microbes was reconstructed from the metagenome, and we identified a set of dysregulated metabolic pathways significantly enriched in the periodontitis and/or diabetic patients. These pathways were mainly involved in branched and aromatic amino acids metabolism, fatty acid biosynthesis and adipocytokine signaling pathways, ferroptosis and iron homeostasis, nucleotide metabolism, and finally in the peptidoglycan and lipopolysaccharides synthesis. Overall, the results of the present study provide evidence in favor of the hypothesis that during the primary inflammatory challenge, regardless of whether it is induced by periodontitis or diabetes, endotoxemia and/or the release of inflammatory cytokines cause a change in precursor and/or in circulating innate immune cells. Dysbiosis and inflammation, also via oral-gut microbiome axis or adipose tissue, reduce the efficacy of the host immune response, while fueling inflammation and can induce that metabolic/epigenetic reprogramming of chromatin accessibility of genes related to the immune response. Moreover, the presence of an enhanced ferroptosis and an imbalance in purine/pyrimidine metabolism provides new insights into the role of ferroptotic death in this comorbidity.

Evolutionary History of Periodontitis and the Oral Microbiota—Lessons for the Future

Purpose of Review

Currently, periodontal disease is the sixth most prevalent disease in the world. Emerging evidence suggests the possibility of pre-historic humans having relatively low occurrences of oral diseases, particularly periodontitis when compared to modern humans. In this review, we look back into the history of Homo sapiens and explore the emerging scientific literature to discuss the evolution of the human oral microbiota and the prevalence of periodontitis from pre-historic to modern times.

Recent Findings

Most of the scientific literature points to a more health-associated, eubiotic oral microbiota and a seemingly lower prevalence of periodontitis in pre-historic humans compared to modern times. The oral microbiome has evolved along with humans. Humans of the contemporary era are exposed to a far greater number of risk factors for periodontal disease. Also, major lifestyle changes induced by the agricultural revolution and the industrial revolution have led to the development of a more dysbiotic oral microbiota and a rise in the prevalence of periodontitis in modern humans.

Summary

An understanding of the prevalence of periodontitis across human history, the evolution of the oral microbiota, and the factors that influenced its nature and complexity helps identify and modify the disease-associated lifestyle factors acquired through modernization to manage the common worldwide problem of periodontitis.

The Role of Interleukin 6 in Periodontitis and Its Complications

Interleukin 6 (IL-6) is a pleomorphic pro-inflammatory cytokine that is strongly associated with local as well as systemic inflammatory processes. Its role in physiological and pathogenic processes throughout the human body has been the subject of numerous studies in recent years. Measurements of the IL-6 levels in gingival crevicular fluid (GFC), as well as in serum, can be important diagnostic and prognostic factors in periodontal diseases (PD) and in assessing their impact on a range of related inflammatory diseases. This narrative review explores the significant role of IL-6 in patients with periodontitis and its association with other widespread inflammatory pathologies.

Polymicrobial Infection Induces Adipose Tissue Dysfunction via Gingival Extracellular Vesicles

Recent studies have indicated that periodontitis promotes metabolic dysregulation and insulin resistance by affecting the function of white adipose tissue (WAT). However, the mechanisms linking periodontitis to adipose tissue dysfunction still need to be explored. Extracellular vesicles (EVs) deliver messages to distal sites and regulate their function. Also, recent studies have shown that periodontitis changes the composition of EVs in body fluids and that EVs might be one of the mechanisms underlying the relationship between periodontitis and insulin resistance. Herein, we explored the impact of polymicrobial oral infection with periodontal pathogens on the function of WAT and the role of gingival EVs (gEVs) in the process. Mice were subjected to oral inoculation with 109 Porphyromonas gingivalis and 108 Fusobacterium nucleatum every other day for 14 wk. This prolonged bacterial infection induced WAT dysfunction, characterized by reduced levels of AKT phosphorylation, adiponectin, leptin, and genes associated with adipogenesis and lipogenesis. We successfully isolated gEVs with satisfactory yield and purity. The RNA sequencing results showed that the differentially expressed microRNAs in the gEVs of mice with polymicrobial oral infection were involved in insulin signaling and adipose tissue function. Notably, our in vitro experiments and RNA sequencing results revealed the functional similarities between gEVs and plasma-derived EVs. Furthermore, intraperitoneal injection with gEVs derived from mice with oral infection induced the dysfunction of WAT in healthy mice. Overall, our findings provide evidence for the influence of polymicrobial oral infection on WAT function and propose gEVs as a novel pathway through which periodontal infection may exert its effects on WAT.

Low-level laser therapy alleviates periodontal age-related inflammation in diabetic mice via the GLUT1/mTOR pathway

Diabetes mellitus (DM) is a chronic age-related disease that was recently found as a secondary aging pattern regulated by the senescence associated secretory phenotype (SASP). The purpose of this study is to detect the potential efficacy and the specific mechanisms of low-level laser therapy (LLLT) healing of age-related inflammation (known as inflammaging) in diabetic periodontitis. Diabetic periodontitis (DP) mice were established by intraperitoneal streptozotocin (STZ) injection and oral P. gingivalis inoculation. Low-level laser irradiation (810 nm, 0.1 W, 398 mW/cm2, 4 J/cm2, 10 s) was applied locally around the periodontal lesions every 3 days for 2 consecutive weeks. Micro-CT and hematoxylin-eosin (HE) stain was analyzed for periodontal soft tissue and alveolar bone. Western blots, immunohistochemistry, and immunofluorescence staining were used to evaluate the protein expression changes on SASP and GLUT1/mTOR pathway. The expression of aging-related factors and SASP including tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 were reduced in periodontal tissue of diabetic mice. The inhibitory effect of LLLT on GLUT1/mTOR pathway was observed by detecting the related factors mTOR, p-mTOR, GLUT1, and PKM2. COX, an intracytoplasmic photoreceptor, is a key component of the anti-inflammatory effects of LLLT. After LLLT treatment a significant increase in COX was observed in macrophages in the periodontal lesion. Our findings suggest that LLLT may regulate chronic low-grade inflammation by modulating the GLUT1/mTOR senescence-related pathway, thereby offering a potential treatment for diabetic periodontal diseases.

Current scientific evidence for why periodontitis should be included in diabetes management

This Perspective provides a brief summary of the scientific evidence for the two-way links between periodontal diseases and hyperglycemia (diabetes mellitus [DM] and pre-DM). It delivers in a nutshell current scientific evidence for manifestations of hyperglycemia on periodontal health status and effects of periodontal diseases on blood glucose levels and in turn incidence, progression, and complications of diabetes. Of outmost importance is presentation of scientific evidence for the potential of routine periodontal treatment to lower blood glucose levels, providing a novel, economical tool in DM management. Non-surgical periodontal treatment ("deep cleaning") can be provided by dental hygienists or dentists in general dental offices, although severe cases should be referred to specialists. Such therapy can decrease the costs of DM care and other health care costs for people with DM. The great importance of a healthy oral cavity free of infection and subsequent inflammation - especially periodontitis that if untreated will cause loosening and eventually loss of affected teeth - has largely gone unnoticed by the medical community as the health care curricula are largely void of content regarding the bi-directional links between oral health and systemic health, despite elevation of blood glucose levels being an integral part of the general systemic inflammation response. The importance of keeping disease-free, natural teeth for proper biting and chewing, smiling, self-esteem, and pain avoidance cannot be overestimated. Medical and dental professionals are strongly encouraged to collaborate in patient-centered care for their mutual patients with - or at risk for - hyperglycemia.

Establishment of models to predict factors influencing periodontitis in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with periodontitis. Currently, there are few studies proposing predictive models for periodontitis in patients with T2DM.

AIM

To determine the factors influencing periodontitis in patients with T2DM by constructing logistic regression and random forest models.

METHODS

In this a retrospective study, 300 patients with T2DM who were hospitalized at the First People's Hospital of Wenling from January 2022 to June 2022 were selected for inclusion, and their data were collected from hospital records. We used logistic regression to analyze factors associated with periodontitis in patients with T2DM, and random forest and logistic regression prediction models were established. The prediction efficiency of the models was compared using the area under the receiver operating characteristic curve (AUC).

RESULTS

Of 300 patients with T2DM, 224 had periodontitis, with an incidence of 74.67%. Logistic regression analysis showed that age [odds ratio (OR) = 1.047, 95% confidence interval (CI): 1.017-1.078], teeth brushing frequency (OR = 4.303, 95%CI: 2.154-8.599), education level (OR = 0.528, 95%CI: 0.348-0.800), glycosylated hemoglobin (HbA1c) (OR = 2.545, 95%CI: 1.770-3.661), total cholesterol (TC) (OR = 2.872, 95%CI: 1.725-4.781), and triglyceride (TG) (OR = 3.306, 95%CI: 1.019-10.723) influenced the occurrence of periodontitis (P < 0.05). The random forest model showed that the most influential variable was HbA1c followed by age, TC, TG, education level, brushing frequency, and sex. Comparison of the prediction effects of the two models showed that in the training dataset, the AUC of the random forest model was higher than that of the logistic regression model (AUC = 1.000 vs AUC = 0.851; P < 0.05). In the validation dataset, there was no significant difference in AUC between the random forest and logistic regression models (AUC = 0.946 vs AUC = 0.915; P > 0.05).

CONCLUSION

Both random forest and logistic regression models have good predictive value and can accurately predict the risk of periodontitis in patients with T2DM.

The rosetta stone of successful ageing: does oral health have a role?

Ageing is an inevitable aspect of life and thus successful ageing is an important focus of recent scientific efforts. The biological process of ageing is mediated through the interaction of genes with environmental factors, increasing the body's susceptibility to insults. Elucidating this process will increase our ability to prevent and treat age-related disease and consequently extend life expectancy. Notably, centenarians offer a unique perspective on the phenomenon of ageing. Current research highlights several age-associated alterations on the genetic, epigenetic and proteomic level. Consequently, nutrient sensing and mitochondrial function are altered, resulting in inflammation and exhaustion of regenerative ability.Oral health, an important contributor to overall health, remains underexplored in the context of extreme longevity. Good masticatory function ensures sufficient nutrient uptake, reducing morbidity and mortality in old age. The relationship between periodontal disease and systemic inflammatory pathologies is well established. Diabetes, rheumatoid arthritis and cardiovascular disease are among the most significant disease burdens influenced by inflammatory oral health conditions. Evidence suggests that the interaction is bi-directional, impacting progression, severity and mortality. Current models of ageing and longevity neglect an important factor in overall health and well-being, a gap that this review intends to illustrate and inspire avenues for future research.

Effect of Insulin on Bone Formation Ability of Rat Alveolar Bone Marrow Mesenchymal Stem Cells

The alveolar bone marrow mesenchymal stem cells (ABM-MSCs) play an important role in oral bone healing and regeneration. Insulin is considered to improve impaired oral bones due to local factors, systemic factors and pathological conditions. However, the effect of insulin on bone formation ability of ABM-MSCs still needs to be elucidated. The aim of this study was to determine the responsiveness of rat ABM-MSCs to insulin and to explore the underlying mechanism. We found that insulin promoted ABM-MSCs proliferation in a concentration-dependent manner, in which 10-6 M insulin exerted the most significant effect. 10-6 M insulin significantly promoted the type I collagen (COL-1) synthesis, alkaline phosphatase (ALP) activity, osteocalcin (OCN) expression, and mineralized matrix formation in ABM-MSCs, significantly enhanced the gene and protein expressions of intracellular COL-1, ALP, and OCN. Acute insulin stimulation significantly promoted insulin receptor (IR) phosphorylation, IR substrate-1 (IRS-1) protein expression, and mammalian target of rapamycin (mTOR) phosphorylation, but chronic insulin stimulation decreased these values, while inhibitor NT219 could attenuate these responses. When seeded on β-tricalcium phosphate (β-TCP), ABM-MSCs adhered and grew well, during the 28-day culture period, ABM-MSCs+β-TCP +10-6 M insulin group showed significantly higher extracellular total COL-1 amino-terminus prolongation peptide content, ALP activity, OCN secretion, and Ca and P concentration. When implanted subcutaneously in severe combined immunodeficient mice for 1 month, the ABM-MSCs+β-TCP +10-6 M insulin group obtained the most bone formation and blood vessels. These results showed that insulin promoted the proliferation and osteogenic differentiation of ABM-MSCs in vitro, and enhance osteogenesis and angiogenesis of ABM-MSCs in vivo. Inhibition studies demonstrated that the insulin-induced osteogenic differentiation of ABM-MSCs was dependent of insulin/mTOR signaling. It suggests that insulin has a direct anabolic effect on ABM-MSCs.

Influence of Diabetes Mellitus and Smoking on Pro- and Anti-Inflammatory Cytokine Profiles in Gingival Crevicular Fluid

Smoking and diabetes mellitus have been recognized as significant modifying factors of the evolution of periodontitis, being considered at the moment as descriptive factors in the periodontitis grading system. The purpose of this study was to assess the consequence of smoking, type 2 diabetes, and the combination of these two factors on clinical periodontal parameters, on the levels of gingival crevicular fluid (GCF), and also on ratios of pro-inflammatory and anti-inflammatory cytokines by using a commercially available kit-based multiplex fluorescent immunoassay. The study was carried out on 124 volunteers (control (C) group = 29, diabetes mellitus (DM) group = 32, smoking (S) group = 31, and S + DM group = 32). Total mean bleeding on probing was significantly lower in the S and S + DM groups, compared to that of the other groups (p < 0.05). Total amounts of TGF-β, MIP-1α, IL-6, IL-2, and IL-17 were significantly increased in the periodontally healthy sites of diabetes patients (p < 0.05), compared to those of the controls. Systemically healthy smoking patients had higher values of GM-CSF, TGF-β, IL-4, TNF-α, IL-5, and IL-7, while diabetic smoking patients showed higher values of IL-4, TGF-β, and MIP-1α. In smoking and systemically healthy patients, IL-23, IL-7, and IL-12 showed increased concentrations, while concentrations of TGF-β, MIP-1α, IL-2, IL-7, IL-12, IL-17, IL-21, and IL-23 were higher in smoking DM patients. In conclusion, in our study, diabetes mellitus induced a general pro-inflammatory state, while smoking mainly stimulated immunosuppression in the periodontal tissues of periodontitis subjects.

Diabetes mellitus promotes susceptibility to periodontitis-novel insight into the molecular mechanisms

Diabetes mellitus is a main risk factor for periodontitis, but until now, the underlying molecular mechanisms remain unclear. Diabetes can increase the pathogenicity of the periodontal microbiota and the inflammatory/host immune response of the periodontium. Hyperglycemia induces reactive oxygen species (ROS) production and enhances oxidative stress (OS), exacerbating periodontal tissue destruction. Furthermore, the alveolar bone resorption damage and the epigenetic changes in periodontal tissue induced by diabetes may also contribute to periodontitis. We will review the latest clinical data on the evidence of diabetes promoting the susceptibility of periodontitis from epidemiological, molecular mechanistic, and potential therapeutic targets and discuss the possible molecular mechanistic targets, focusing in particular on novel data on inflammatory/host immune response and OS. Understanding the intertwined pathogenesis of diabetes mellitus and periodontitis can explain the cross-interference between endocrine metabolic and inflammatory diseases better, provide a theoretical basis for new systemic holistic treatment, and promote interprofessional collaboration between endocrine physicians and dentists.

Osteoimmunology in Periodontitis and Orthodontic Tooth Movement

PURPOSE OF REVIEW

To review the role of the immune cells and their interaction with cells found in gingiva, periodontal ligament, and bone that leads to net bone loss in periodontitis or bone remodeling in orthodontic tooth movement.

RECENT FINDINGS

Periodontal disease is one of the most common oral diseases causing inflammation in the soft and hard tissues of the periodontium and is initiated by bacteria that induce a host response. Although the innate and adaptive immune response function cooperatively to prevent bacterial dissemination, they also play a major role in gingival inflammation and destruction of the connective tissue, periodontal ligament, and alveolar bone characteristic of periodontitis. The inflammatory response is triggered by bacteria or their products that bind to pattern recognition receptors that induce transcription factor activity to stimulate cytokine and chemokine expression. Epithelial, fibroblast/stromal, and resident leukocytes play a key role in initiating the host response and contribute to periodontal disease. Single-cell RNA-seq (scRNA-seq) experiments have added new insight into the roles of various cell types in the response to bacterial challenge. This response is modified by systemic conditions such as diabetes and smoking. In contrast to periodontitis, orthodontic tooth movement (OTM) is a sterile inflammatory response induced by mechanical force. Orthodontic force application stimulates acute inflammatory responses in the periodontal ligament and alveolar bone stimulated by cytokines and chemokines that produce bone resorption on the compression side. On the tension side, orthodontic forces induce the production of osteogenic factors, stimulating new bone formation. A number of different cell types, cytokines, and signaling/pathways are involved in this complex process. Inflammatory and mechanical force-induced bone remodeling involves bone resorption and bone formation. The interaction of leukocytes with host stromal cells and osteoblastic cells plays a key role in both initiating the inflammatory events as well as inducing a cellular cascade that results in remodeling in orthodontic tooth movement or in tissue destruction in periodontitis.

Eldecalcitol effectively prevents alveolar bone loss by partially improving Th17/Treg cell balance in diabetes-associated periodontitis

Background: Diabetes-associated periodontitis (DPD) is an inflammatory and destructive disease of periodontal tissues in the diabetic population. The disease is manifested as more severe periodontal destruction and is more difficult to treat when compared with periodontitis (PD). Eldecalcitol (ELD) is a novel active vitamin D3 analog; however, little clinical evidence is available on its role on improving PD and DPD, and its specific mechanisms remain unclear. In this study, we evaluated the preventative effects of ELD toward PD and DPD and explored its underlying molecular mechanisms. Methods: Experimental PD and DPD mouse models were established by ligation combined with lipopolysaccharide (LPS) from Porphyromonas gingivalis injection in C57BL/6J and C57BLKS/J Iar- + Leprdb/+Leprdb (db/db) mice, respectively. Simultaneously, ELD (0.25 μg/kg) was orally administered to mice via an intragastric method. Micro-computed tomography (CT), hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), and tartrate-resistant acid phosphatase (TRAP) staining were used to evaluate alveolar bone alterations in vivo. Flow cytometry, immunofluorescence, and real-time polymerase chain reaction (qRT-PCR) were also used to examine gene expression and probe systemic and local changes in Treg and Th17 cell numbers. Additionally, western blotting and immunofluorescence staining were used to examine changes in STAT3/STAT5 signaling. Results: Micro-CT and HE staining showed that the DPD group had higher alveolar bone loss when compared with the PD group. After applying ELD, alveolar bone loss decreased significantly in both PD and DPD groups, and particularly evident in the DPD group. IHC and TRAP staining also showed that ELD promoted osteoblast activity while inhibiting the number of osteoclasts, and after ELD treatment, the receptor activator of nuclear factor-κB ligand (RANKL) to osteoprotegerin (OPG) ratio decreased. More importantly, this decreasing trend was more obvious in the DPD group. Flow cytometry and qRT-PCR also showed that the systemic Th17/Treg imbalance in PD and DPD groups was partially resolved when animals were supplemented with ELD, while immunofluorescence staining and qRT-PCR data showed the Th17/Treg imbalance was partially resolved in the alveolar bone of both ELD supplemented groups. Western blotting and immunofluorescence staining showed increased p-STAT5 and decreased p-STAT3 levels after ELD application. Conclusion: ELD exerted preventative effects toward PD and DPD by partially rectifying Th17/Treg cell imbalance via STAT3/STAT5 signaling. More importantly, given the severity of DPD, we found ELD was more advantageous in preventing DPD.

Visualized analysis of hotspots and frontiers in diabetes-associated periodontal disease research: a bibliometric study

Background

Diabetes-associated periodontal disease is caused by diabetes-enhanced host immune-inflammatory responses to bacterial insult. An increasing number of papers related to diabetes-associated periodontal disease have been published. This study analyzed research on diabetes-associated periodontal disease with bibliometrics methods. The objective of this study was to identify hotspots and frontiers in the diabetes-associated periodontal disease research field.

Methods

Publications were extracted from the Web of Science core collection database, and the document types included were limited to articles and reviews. The bibliometric analysis software CiteSpace5 was used to analyze the number of articles, research fields, countries/regions, institutions, authors, keywords, and other information. Outcomes were visualized to analyze the hotspots and research frontiers of diabetes-associated periodontal disease.

Results

A total of 3,572 articles were retrieved. Among the research fields, dentistry, oral surgery, and medicine accounted for the highest proportion of publications, and public, environmental, and occupational health had the highest betweenness centrality. The number of publications from the United States ranked first among all the countries, while Columbia University ranked first among all the institutions. Global cooperation was not frequent. Keyword analysis showed that inflammatory pathways were the hotspots. Burst words analysis indicated that early prevention was a research frontier.

Conclusions

The bibliometric method helped identify research hotspots and frontiers. Inflammatory pathways were hotspots, and early prevention was a frontier in diabetes-associated periodontal disease.

Exploration of cross-talk and pyroptosis-related gene signatures and molecular mechanisms between periodontitis and diabetes mellitus via peripheral blood mononuclear cell microarray data analysis

OBJECTIVES

This bioinformatics study is aimed at identifying cross-talk genes, pyroptosis-related genes, and related pathways between periodontitis (PD) and diabetes mellitus (DM), which includes type 1 diabetes (T1DM) and type 2 diabetes (T2DM).

METHODS

GEO datasets containing peripheral blood mononuclear cell (PBMC) data of PD and DM were acquired. After batch correction and normalization, differential expression analysis was performed to identify the differentially expressed genes (DEGs). And cross-talk genes in the PD-T1DM pair and the PD-T2DM pair were identified by overlapping DEGs with the same trend in each pair. The weighted gene coexpression network analysis (WGCNA) algorithm helped locate the pyroptosis-related genes that are related to cross-talk genes. Receiver-operating characteristic (ROC) curve analysis confirmed the predictive accuracy of these hub genes in diagnosing PD and DM. The correlation between hub genes and the immune microenvironment of PBMC in these diseases was investigated by Spearman correlation analysis. The experimentally validated protein-protein interaction (PPI) and gene-pathway network were constructed. Subnetwork analysis helped identify the key pathway connecting DM and PD.

RESULTS

Hub genes in the PD-T1DM pair (HBD, NLRC4, AIM2, NLRP2) and in the PD-T2DM pair (HBD, IL-1Β, AIM2, NLRP2) were identified. The similarity and difference in the immunocytes infiltration levels and immune pathway scores of PD and DM were observed. ROC analysis showed that AIM2 and HBD exhibited pleasant discrimination ability in all diseases, and the subnetwork of these genes indicated that the NOD-like receptor signaling pathway is the most potentially relevant pathway linking PD and DM.

CONCLUSION

HBD and AIM2 could be the most relevant potential cross-talk and pyroptosis-related genes, and the NOD-like receptor signaling pathway could be the top candidate molecular mechanism linking PD and DM, supporting a potential pathophysiological relationship between PD and DM.

Periodontitis and Its Inflammatory Changes Linked to Various Systemic Diseases: A Review of Its Underlying Mechanisms

Periodontitis is a chronic inflammatory disease of the gums. The incidence of periodontitis is increasing all over the world. In patients with periodontitis, there is gradual destruction of the periodontal ligament and the alveolar bone, and later, in advanced stages, there is tooth loss. Different microorganisms, the host’s immune response, and various environmental factors interact in the progression of this chronic inflammatory disease. In the present review, we discuss the epidemiology, clinical features, diagnosis, and complications of periodontitis. We also discuss the association of chronic inflammation found in periodontitis with various other systemic diseases, which include cardiovascular, respiratory, diabetes, Alzheimer’s, cancer, adverse pregnancy, and multiple myeloma, and also highlight microbial carcinogenesis and the microRNAs involved. The latest updates on the molecular mechanism, possible biomarkers, and treatment procedures may be beneficial for diagnostic and therapeutic purposes.

Host Response Modulation Therapy in the Diabetes Mellitus—Periodontitis Conjuncture: A Narrative Review

The inflammatory response of the host in periodontitis is the phenomenon that underlies the onset and evolution of periodontal destructive phenomena. A number of systemic factors, such as diabetes mellitus (DM), can negatively affect the patient with periodontitis, just as the periodontal disease can aggravate the status of the DM patient. Host response modulation therapy involves the use of anti-inflammatory and anti-oxidant products aimed at resolving inflammation, stopping destructive processes, and promoting periodontal healing, all important aspects in patients with high tissue loss rates, such as diabetic patients. This paper reviews the data available in the literature on the relationship between DM and periodontitis, the main substances modulating the inflammatory response (nonsteroidal anti-inflammatory drugs, sub-antimicrobial doses of doxycycline, or omega-3 fatty acids and their products, specialized pro-resolving mediators), as well as their application in diabetic patients.

Titanium Surface Characteristics Induce the Specific Reprogramming of Toll-like Receptor Signaling in Macrophages

Most of the research on titanium-based dental implants (Ti-discs) is focused on how they are able to stimulate the formation of new tissue and/or cytotoxic studies, with very scarce data on their effects on functional responses by immunocompetent cells. In particular, the link between the rewiring of innate immune responses and surface biomaterials properties is poorly understood. To address this, we characterize the functional response of macrophage cultures to four different dental titanium surfaces (MA: mechanical abrasion; SB + AE: sandblasting plus etching; SB: sandblasting; AE: acid etching). We use different Toll-like receptor (TLR) ligands towards cell surface receptors (bacterial lipopolysaccharide LPS for TLR4; imiquimod for TLR7; synthetic bacterial triacylated lipoprotein for TLR2/TLR1) and endosomal membrane receptor (poly I:C for TLR3) to simulate bacterial (cell wall bacterial components) or viral infections (dsRNA and ssRNA). The extracellular and total LDH levels indicate that exposure to the different Ti-surfaces is not cytotoxic for macrophages under resting or TLR-stimulated conditions, although there is a tendency towards an impairment in macrophage proliferation, viability or adhesion under TLR4, TLR3 and TLR2/1 stimulations in SB discs cultures. The secreted IL-6 and IL-10 levels are not modified upon resting macrophage exposure to the Ti-surfaces studied as well as steady state levels of iNos or ArgI mRNA. However, macrophage exposure to MA Ti-surface do display an enhanced immune response to TLR4, TLR7 or TLR2/1 compared to other Ti-surfaces in terms of soluble immune mediators secreted and M1/M2 gene expression profiling. This change of characteristics in cellular phenotype might be related to changes in cellular morphology. Remarkably, the gene expression of Tlr3 is the only TLR that is differentially affected by distinct Ti-surface exposure. These results highlight the relevance of patterned substrates in dental implants to achieve a smart manipulation of the immune responses in the context of personalized medicine, cell-based therapies, preferential lineage commitment of precursor cells or control of tissue architecture in oral biology.