Glucagon-Like Peptide-1 Receptor Agonist Liraglutide Ameliorates the Development of Periodontitis

Glucagon-Like Peptide 1 Receptor Agonists (GLP-1RAs) Improve Periodontal and Peri-Implant Health in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) affects millions globally and is strongly associated with oral health issues, particularly periodontitis. The bidirectional relationship between T2DM and periodontitis is well established, with poorly managed T2DM increasing the risk of inflammation, tissue damage, and dental implant failure. Advances in treatment, such as glucagon-like peptide 1 receptor agonists (GLP-1RAs), have led to better glycemic control and may reduce T2DM-related complications, highlighting their potential in addressing interconnected oral-systemic health challenges. This narrative review critically evaluates the literature on the impact of GLP-1RAs on periodontal and peri-implant health. 10 in vitro studies, nine preclinical animal studies, and one clinical study were explored to investigate their effects on periodontal regeneration, implant therapy, and related mechanisms. In vitro research revealed that GLP-1RAs, including exenatide and liraglutide, promoted osteogenic differentiation of periodontal ligament stem cells (PDLSCs) through pathways such as the mitogen Wnt/β-catenin and mitogen-activated protein kinase pathways, even in high glucose or inflammatory conditions. Synergistic effects with stromal cell-derived factor-1 further promoted PDLSC proliferation and bone regeneration. Animal studies demonstrated that GLP-1RAs mitigated periodontal inflammation, oxidative stress, and alveolar bone resorption while promoting bone remodeling and implant osseointegration, independently of glycemic control. Importantly, advanced delivery systems, such as exenatide-loaded chitosan-poly(lactic-coglycolic acid) microspheres, further increased peri-implant osseointegration in diabetic models. The sole clinical study, a retrospective cohort study, assessed peri-implant marginal bone loss in peri-implantitis patients treated with different hypoglycemic drugs. Results showed significantly less clinical and radiographic bone loss in the GLP-1RA group compared to insulin and metformin groups (p < 0.01). Overall, while GLP-1RAs have promising anti-inflammatory, osteoprotective, and pleiotropic properties, their role appears more aligned with preserving periodontal and peri-implant health in T2DM individuals than directly treating periodontitis or peri-implantitis. By delineating current evidence and research directions, this review calls for medical and dental professionals to collaborate in leveraging these novel treatment options in future studies to improve patient care and address the intricate challenges that diabetes presents to oral health.

Smoking impairs cognitive function through the mediating effect of periodontitis in older adults

OBJECTIVES

Evidence has shown that both smoking and periodontitis were linked to cognitive impairment. This study examines whether periodontitis mediates the effects of smoking status on cognitive function in older adults.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, the study included 1728 older participants who have data on smoking, serum cotinine, periodontal examination, and cognitive function. Mediation analysis was performed to test whether extent of periodontitis mediated associations between smoking status and cognitive function, adjusted for sociodemographic and basic health factors.

RESULTS

Compared to never-smokers, daily smokers exhibited significantly worse global cognitive function, with periodontitis mediating this effect (effect= -0.16; 95% CI= -0.29, -0.05). Similarly, periodontitis mediated the association between serum cotinine levels and cognitive function in the total sample (effect= -0.02; 95% CI= -0.03, -0.00).

CONCLUSIONS

Periodontitis significantly mediates the impact of smoking on cognitive function. The findings highlight the potential roles of maintaining oral health and smoking cessation in mitigating cognitive decline.

HOXD9/APOC1 axis promotes macrophage M1 polarization to exacerbate diabetic kidney disease progression through activating NF-κB signaling pathway

BACKGROUND

Diabetic kidney disease (DKD) is a complication caused by end-stage diabetes mellitus and usually results in glomerular podocyte injury. Exosomes are important for intercellular information exchange. However, the effect of podocyte exosomes on DKD has not been elucidated.

METHODS

GEO, PROMO, and GSE1009 databases were used to identify the gene APOC1 and transcription factor HOXD9. qRT-PCR, western blot, and transmission electron microscopy (TEM) were investigated to confirm APOC1 change in high glucose-treated podocytes and exosomes. Flow cytometry, immunofluorescence, qPCR, immunoblotting, wound healing, Transwell invasion assays, dual luciferase assay, and ChIP-PCR assay were performed to detect the effect of APOC1 and HOXD9 on macrophage polarization in high glucose-treated podocytes and exosomes. qRT-PCR and immunoblotting assays were employed to assess the impact of APOC1 knockdown on the M1 polarization of macrophages in response to liraglutide treatment.

RESULTS

The results suggested that the expression of APOC1 in human podocytes (HPC) and exosomes was elevated. High glucose-treated HPC exosomes promoted macrophage M1-type polarization, which was reversed by adding sh-APOC1. Afterward, HOXD9 was identified as a potential transcription factor for APOC1. Knockdown of HOXD9 led to macrophage M2 polarization, and overexpression of APOC1 polarized macrophage M1. In addition, enhanced p65 phosphorylation verified that HOXD9/APOC1 induced macrophage M1-type polarization by activating the NF-κB signaling pathway. Knocking down APOC1 enhanced the inhibitory effect of liraglutide on macrophage M1 polarization.

CONCLUSION

Our findings highlighted that HOXD9/APOC1 was a key player in causing podocyte injury in diabetic kidney disease and led to macrophage M1 polarization through the NF-κB signaling pathway.

Heme oxygenase-1: potential therapeutic targets for periodontitis

Periodontitis is one of the most prevalent inflammatory disease worldwide, which affects 11% of the global population and is a major cause of tooth loss. Recently, oxidative stress (OS) has been found to be the pivital pathophysiological mechanism of periodontitis, and overactivated OS will lead to inflammation, apoptosis, pyroptosis and alveolar bone resorption. Interestingly, heme oxygenase-1 (HO-1), a rate-limiting enzyme in heme degradation, can exert antioxidant activites through its products-carbon monoxide (CO), Fe2+, biliverdin and bilirubin in the inflammatory microenvironment, thus exhibiting anti-inflammatory, anti-apoptotic, anti-pyroptosis and bone homeostasis-regulating properties. In this review, particular focus is given to the role of HO-1 in periodontitis, including the spatial-temporal expression in periodental tissues and pathophysiological mechanisms of HO-1 in periodontitis, as well as the current therapeutic applications of HO-1 targeted drugs for periodontitis. This review aims to elucidate the potential applications of various HO-1 targeted drug therapy in the management of periodontitis, investigate the influence of diverse functional groups on HO-1 and periodontitis, and pave the way for the development of a new generation of therapeutics that will benefit patients suffering from periodontitis.

Lipotoxicity: The missing link between diabetes and periodontitis?

Lipotoxicity refers to the accumulation of lipids in tissues other than adipose tissue (body fat). It is one of the major pathophysiological mechanisms responsible for the progression of diabetes complications such as non-alcoholic fatty liver disease and diabetic nephropathy. Accumulating evidence indicates that lipotoxicity also contributes significantly to the toxic effects of diabetes on periodontitis. Therefore, we reviewed the current in vivo, in vitro, and clinical evidence of the detrimental effects of lipotoxicity on periodontitis, focusing on its molecular mechanisms, especially oxidative and endoplasmic reticulum stress, inflammation, ceramides, adipokines, and programmed cell death pathways. By elucidating potential therapeutic strategies targeting lipotoxicity and describing their associated mechanisms and clinical outcomes, including metformin, statins, liraglutide, adiponectin, and omega-3 PUFA, this review seeks to provide a more comprehensive and effective treatment framework against diabetes-associated periodontitis. Furthermore, the challenges and future research directions are proposed, aiming to contribute to a more profound understanding of the impact of lipotoxicity on periodontitis.

Dipeptidyl-Peptidase-4 and Glucagon-like-Peptide-1, a Link in the Connection between Periodontitis and Diabetes Mellitus-What Do We Know So Far?-A Scoping Review

Periodontitis is a common condition affecting the tissues surrounding and supporting teeth. In addition to oral health concerns, periodontal disease increases the chance of developing systemic illnesses including type 2 diabetes mellitus. Porphyromonas gingivalis, a key-stone pathogen that has been linked to the pathophysiology of periodontal disease, can generate a series of dipeptide producing exopeptidases, dipeptidyl peptidases (DPP). DPP-4 levels in gingival crevicular fluid have been shown to increase during active periodontal disease, which may lead to their association with the disease's progression. Following oral glucose administration, mice injected with DPP-4 had higher blood glucose than the control group. DPP-4 inhibitors are used to treat patients with type 2 diabetes mellitus in order to extend the half-life of incretins. Elevated glucagon-like peptide-1 (GLP-1) levels following periodontal therapy could be considered new and applicable real-world evidence confirming the experimental findings of a beneficial interaction between oral microbiota and incretin axis. GLP-1 receptor agonist exendin-4 enhanced the osteoblast proliferation and development of these stem cells and inhibited the effects of glucose on the cells. In addition to lowering blood sugar, liraglutide, a GLP-1 receptor agonist, also possesses anti-inflammatory and bone-protective properties. These findings support the use of GLP-1 in the management and prevention of diabetic periodontitis.

GLP-1 receptor agonist as a modulator of innate immunity

Glucagon-like peptide-1 (GLP-1) is a 30-amino acid hormone secreted by L cells in the distal ileum, colon, and pancreatic α cells, which participates in blood sugar regulation by promoting insulin release, reducing glucagon levels, delaying gastric emptying, increasing satiety, and reducing appetite. GLP-1 specifically binds to the glucagon-like peptide-1 receptor (GLP-1R) in the body, directly stimulating the secretion of insulin by pancreatic β-cells, promoting proliferation and differentiation, and inhibiting cell apoptosis, thereby exerting a glycemic lowering effect. The glycemic regulating effect of GLP-1 and its analogues has been well studied in human and murine models in the circumstance of many diseases. Recent studies found that GLP-1 is able to modulate innate immune response in a number of inflammatory diseases. In the present review, we summarize the research progression of GLP-1 and its analogues in immunomodulation and related signal pathways.

Next-Generation Examination, Diagnosis, and Personalized Medicine in Periodontal Disease

Periodontal disease, a major cause of tooth loss, is an infectious disease caused by bacteria with the additional aspect of being a noncommunicable disease closely related to lifestyle. Tissue destruction based on chronic inflammation is influenced by host and environmental factors. The treatment of periodontal disease varies according to the condition of each individual patient. Although guidelines provide standardized treatment, optimization is difficult because of the wide range of treatment options and variations in the ideas and skills of the treating practitioner. The new medical concepts of “precision medicine” and “personalized medicine” can provide more predictive treatment than conventional methods by stratifying patients in detail and prescribing treatment methods accordingly. This requires a new diagnostic system that integrates information on individual patient backgrounds (biomarkers, genetics, environment, and lifestyle) with conventional medical examination information. Currently, various biomarkers and other new examination indices are being investigated, and studies on periodontal disease-related genes and the complexity of oral bacteria are underway. This review discusses the possibilities and future challenges of precision periodontics and describes the new generation of laboratory methods and advanced periodontal disease treatment approaches as the basis for this new field.

Liraglutide, a glucagon-like peptide 1 receptor agonist, exerts analgesic, anti-inflammatory and anti-degradative actions in osteoarthritis

Osteoarthritis (OA) is a common disabling disease worldwide, with no effective and safe disease-modifying drugs (DMOAD) in the market. However, studies suggest that drugs, such as liraglutide, which possess strong potential in decreasing low-grade systemic inflammation may be effective in treating OA. Therefore, the aim of this study was to examine the anti-inflammatory, analgesic, and anti-degradative effects in OA using in vitro and in vivo experiments. The results showed that intra-articular injection of liraglutide alleviated pain-related behavior in in vivo sodium monoiodoacetate OA mouse model, which was probably driven by the GLP-1R-mediated anti-inflammatory activity of liraglutide. Moreover, liraglutide treatment significantly decreased IL-6, PGE2 and nitric oxide secretion, and the expression of inflammatory genes in vitro in chondrocytes and macrophages in a dose-dependent manner. Additionally, liraglutide shifted polarized macrophage phenotype in vitro from the pro-inflammatory M1 phenotype to the M2 anti-inflammatory phenotype. Furthermore, liraglutide exerted anti-catabolic activity by significantly decreasing the activities of metalloproteinases and aggrecanases, a family of catabolic enzymes involved in cartilage breakdown in vitro. Overall, the findings of this study showed that liraglutide ameliorated OA-associated pain, possess anti-inflammatory and analgesic properties, and could constitute a novel therapeutic candidate for OA treatment.

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

Periodontitis and diabetes are two major global health problems despite their prevalence being significantly underreported and underestimated. Both epidemiological and intervention studies show a bidirectional relationship between periodontitis and diabetes. The hypothesis of a potential causal link between the two diseases is corroborated by recent studies in experimental animals that identified mechanisms whereby periodontitis and diabetes can adversely affect each other. Herein, we will review clinical data on the existence of a two-way relationship between periodontitis and diabetes and discuss possible mechanistic interactions in both directions, focusing in particular on new data highlighting the importance of the host response. Moreover, we will address the hypothesis that trained immunity may represent the unifying mechanism explaining the intertwined association between diabetes and periodontitis. Achieving a better mechanistic insight on clustering of infectious, inflammatory, and metabolic diseases may provide new therapeutic options to reduce the risk of diabetes and diabetes-associated comorbidities.

Effects of Incretin-Related Diabetes Drugs on Bone Formation and Bone Resorption

Patients with type 2 diabetes have an increased risk of fracture compared to the general population. Glucose absorption is accelerated by incretin hormones, which induce insulin secretion from the pancreas. The level of the incretin hormone, glucagon-like peptide-1 (GLP-1), shows an immediate postprandial increase, and the circulating level of intact GLP-1 is reduced rapidly by dipeptidyl peptidase-4 (DPP-4)-mediated inactivation. Therefore, GLP-1 receptor agonists and DPP-4 inhibitors are effective in the treatment of type 2 diabetes. However, these incretin-related diabetic agents have been reported to affect bone metabolism, including bone formation and resorption. These agents enhance the expression of bone markers, and have been applied to improve bone quality and bone density. In addition, they have been reported to suppress chronic inflammation and reduce the levels of inflammatory cytokine expression. Previously, we reported that these incretin-related agents inhibited both the expression of inflammatory cytokines and inflammation-induced bone resorption. This review presents an overview of current knowledge regarding the effects of incretin-related diabetes drugs on osteoblast differentiation and bone formation as well as osteoclast differentiation and bone resorption. The mechanisms by which incretin-related diabetes drugs regulate bone formation and bone resorption are also discussed.