EB 2017 Article: Changes in advanced glycation end products, beta-defensin-3, and interleukin-17 during diabetic periodontitis development in rhesus monkeys

Expression of advanced glycation end products and their receptors in diabetic periodontitis patients

AIM

The systematic review aimed to compare the levels of advanced glycation end products (AGEs) and RAGE (AGE receptors) expression in diabetic periodontitis patients with non-diabetic periodontitis patients and to identify the relationship of AGE and RAGE levels with periodontal disease severity.

MATERIALS AND METHODS

The literature search was carried out according to PRISMA guidelines by two independent researchers using four online databases: PubMed, Scopus, Web of Science Core Collection, and Pro-Quest. Relevant studies published between 2000 and March 2023 were included in this review. The association of diabetes and AGE/RAGE levels on periodontal health, periodontal pocket depth (PPD), and clinical attachment loss (CAL) was studied.

RESULTS

Sixteen cross-sectional studies, including 2794 patients (age range 15-75 years), were identified in the final stage. An elevated AGE level was observed among patients with diabetes and chronic periodontal disease compared to the non-diabetic group. Furthermore, the levels of AGE and RAGE are associated with CAL and PPD. Potential confounding factors like genetic and methodological differences were also responsible for AGE and RAGE variation.

CONCLUSION

Levels of AGEs and RAGE expressions in diabetic periodontitis patients differ from non-diabetic periodontitis patients. The differences may impact the course and severity of periodontal disease.

Are Inflamed Periodontal Tissues Endogenous Source of Advanced Glycation End-Products (AGEs) in Individuals with and without Diabetes Mellitus? A Systematic Review

Advanced glycation end-products (AGEs) are heterogeneous compounds formed when excess sugars condense with the amino groups of nucleic acids and proteins. Increased AGEs are associated with insulin resistance and poor glycemic control. Recently, inflamed periodontal tissues and certain oral bacteria were observed to increase the local and systemic AGE levels in both normoglycemic and hyperglycemic individuals. Although hyperglycemia induced AGE and its effect on the periodontal tissues is known, periodontitis as an endogenous source of AGE formation is not well explored. Hence, this systematic review is aimed to explore, for the first time, whether inflamed periodontal tissues and periodontal pathogens have the capacity to modulate AGE levels in individuals with or without T2DM and how this affects the glycemic load. Six electronic databases were searched using the following keywords: (Periodontitis OR Periodontal disease OR Periodontal Inflammation) AND (Diabetes mellitus OR Hyperglycemia OR Insulin resistance) AND Advanced glycation end products. The results yielded 1140 articles, of which 13 articles were included for the review. The results showed that the mean AGE levels in gingival crevicular fluid was higher in individuals with diabetes mellitus and periodontitis (521.9 pg/mL) compared to healthy individuals with periodontitis (234.84 pg/mL). The serum AGE levels in normoglycemic subjects having periodontitis was higher compared to those without periodontitis (15.91 ng/mL vs. 6.60 ng/mL). Tannerella forsythia, a common gram-negative anaerobe periodontal pathogen in the oral biofilm, was observed to produce methylglyoxal (precursor of AGE) in the gingival tissues. Increased AGE deposition and activate of AGE receptors was noted in the presence of periodontitis in both normoglycemic and hyperglycemic individuals. Hence, it can be concluded that periodontitis can modulate the local and systemic levels of AGE levels even in absence of hyperglycemia. This explains the bidirectional relationship between periodontitis and development of prediabetes, incident diabetes, poor glycemic control, and insulin resistance.

Pathogenic Molecular Mechanisms in Periodontitis and Peri-Implantitis: Role of Advanced Glycation End Products

Advanced Glycation End Products (AGEs), the products of the non-enzymatic oxidation of proteins, nucleic acids, and lipids, are accumulated in periodontal tissues under hyperglycemic conditions such as Diabetes Mellitus (DM) and are responsible for sustained periodontal destruction. AGEs mediate their intracellular effects either directly or indirectly through receptor binding (via RAGE) in all types of periodontal ligament cells (osteocytes, gingival fibroblasts, stem cells, epithelial cells), indicating an important target for intervention. In combination with lipopolysaccharides (LPS) from Porphyromonas gingivalis (Pg), the negative impact of AGEs on periodontal tissue is further enhanced and accentuated. In addition, AGE accumulation is evident in peri-implantitis, yet through different underlying molecular mechanisms. Novel therapeutic approaches targeting the effects of AGEs in periodontal ligament cells show beneficial effects in pre-clinical studies. Herein, we provide evidence on the detrimental role of AGE accumulation in oral cavity tissues and their associated signaling pathways in periodontitis and peri-implantitis to further highlight the significance of oral or topical use of AGE blockers or inhibitors along with dental biofilms’ removal and DM regulation in patients’ management.

Host Defence Peptides in Diabetes Mellitus Type 2 Patients with Periodontal Disease. A Systematic Review

The aim of the study was to critically assess and review the latest evidence relating the associations between host defence peptides (HDPs), periodontal diseases (PD) and diabetes mellitus type 2 (DM2). To explore studies on HDPs, periodontal disease, and DM2, researchers utilised specific key phrases to search the electronic databases PubMed (National Library of Medicine), Embase (Ovid), Medline (EBSCO), and Dentistry and Oral Sciences (EBSCO). Quality assessment was conducted by means of the Newcastle Ottawa scale and the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool. Following a thorough screening process, a total of 12 papers (4 case-control, 6 cross-sectional, 1 animal, and 1 in vitro) fulfilled the selection criteria and were included. The majority of research found that HDPs were upregulated in DM2 patients with PD. Three investigations, however, found that HDPs were downregulated in DM2 patients with PD. HDPs play a part in the pathophysiology of PD and DM2. Nonetheless, more human, animal and laboratory investigations are needed to fully understand validation of the link, as the evidence is limited. Understanding HDPs as common moderators is critical, aimed at unlocking their potential as therapeutic and diagnostic agents.

Subgingival endotoxin and lipoteichoic acid modulate cytokine production in diabetic subjects: A Case-control Study

BACKGROUND

Periodontal disease and diabetes mellitus (DM) are highly prevalent and interrelated diseases, resulting in altered host response microbiota. Thus, this study aimed to evaluate the impact of DM on local levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) and their relationship with cytokines and matrix metalloproteinases' (MMPs) profile.

METHODS

This case-control study included diabetic (n = 15) and non-diabetic (n = 15) subjects presenting Stage 3-4, Grade C, Periodontitis. Gingival crevicular fluid (GCF) was collected, and LPS and LTA levels were analyzed by enzyme-linked immunosorbent assay (ELISA), while IFN-γ, IL-10, IL-17, IL-1β, IL-4, MMP-2, and MMP-9 were measured by LUMINEX/MAGpix. Mann-Whitney and Spearman's correlation tests were used to compared and to correlate variables (p < 0.05).

RESULTS

Higher levels of LTA, LPS, IL-10, IL-1β, and MMP-2 (p < 0.05) and lower levels of IL-17 were found in the DM group (p < 0.05). Non-diabetic subjects presented higher LPS, IFN-γ, IL-17, and MMP-2 levels and lower IL-10 concentration (p < 0.05). No significant correlation was seen between LPS and cytokine profile in non-diabetic. Local levels of LTA were positively correlated with IL-17 and MMP-2 and negatively with IL-10.

CONCLUSION

LTA and LPS drove the inflammatory profile through the modulation of cytokines and MMPs in a different manner in DM and non-diabetic subjects.

6-Shogaol Inhibits Advanced Glycation End-Products-Induced IL-6 and ICAM-1 Expression by Regulating Oxidative Responses in Human Gingival Fibroblasts

Advanced glycation end-products (AGEs) cause diabetes mellitus (DM) complications and accumulate more highly in periodontal tissues of patients with periodontitis and DM. AGEs aggravate periodontitis with DM by increasing the expression of inflammation-related factors in periodontal tissues. 6-Shogaol, a major compound in ginger, has anti-inflammatory and anti-oxidative activities. However, the influence of shogaol on DM-associated periodontitis is not well known. In this study, the effects of 6-shogaol on AGEs-induced oxidative and anti-oxidative responses, and IL-6 and ICAM-1 expression in human gingival fibroblasts (HGFs) were investigated. When HGFs were cultured with 6-shogaol and AGEs, the activities of reactive oxygen species (ROS) and antioxidant enzymes (heme oxygenase-1 [HO-1] and NAD(P)H quinone dehydrogenase 1 [NQO1]), and IL-6 and ICAM-1 expressions were investigated. RAGE expression and phosphorylation of MAPKs and NF-κB were examined by western blotting. 6-Shogaol significantly inhibited AGEs-induced ROS activity, and increased HO-1 and NQO1 levels compared with the AGEs-treated cells. The AGEs-stimulated expression levels of receptor of AGE (RAGE), IL-6 and ICAM-1 and the phosphorylation of p38, ERK and p65 were attenuated by 6-shogaol. These results suggested that 6-shogaol inhibits AGEs-induced inflammatory responses by regulating oxidative and anti-oxidative activities and may have protective effects on periodontitis with DM.