Periodontitis deteriorates metabolic control in type 2 diabetic Goto-Kakizaki rats

Efficacy of scaling and root planing with and without adjunct Nd:YAG laser therapy on glucose control and periodontal microecological imbalance in periodontitis patients with type 2 diabetes mellitus: a randomized controlled trial

OBJECTIVE

The study aims to determine the effects of Nd:YAG laser-assisted with subgingival scaling and root planing (SRP) treatment on glucose control and the dynamic changes of subgingival microbiome in periodontitis with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Twenty-two patients were split into Nd:YAG group (n = 11) and SRP group (n = 11). Patients in the Nd:YAG group received SRP and auxiliary Nd:YAG laser treatment; patients in the SRP group received SRP treatment only. Periodontal tissue inflammation and glycemic control were assessed and analyzed during the treatment period and the changes of subgingival microbiome were analyzed by full-length 16S rRNA sequencing.

RESULTS

After 3 months of treatment, PD and CAL values improved significantly in the Nd:YAG group compared to the SRP group. BOP in both groups improved significantly after treatment. FPG levels in the Nd:YAG group were significantly reduced after treatment. Porphyromonas and Porphyromonadaceae were enriched in the Nd:YAG group at baseline, and Fusobacteriota, Fusobacteriia, Fusobacteriales, Leptotrichiaceae, and Leptotrichia were enriched after treatment.

CONCLUSION

Nd:YAG laser-assisted SRP therapy has additional benefits in improving periodontal tissue inflammation and blood glucose control in periodontitis patients with T2DM compared with SRP therapy alone and there was a trend towards a decrease in disease-associated taxa and an increase in health-associated taxa following auxiliary Nd:YAG laser treatment.

CLINICAL RELEVANCE

The effects of Nd:YAG laser-assisted SRP treatment on inflammation, glucose control, and subgingival microbiome in periodontitis patients with T2DM were elucidated, and new ideas for the treatment of T2DM periodontitis were provided.

Periodontitis promotes the progression of diabetes mellitus by enhancing autophagy

Objective

This study aims to identify the periodontitis factor that activates excessive autophagy in pancreatic β cells, resulting in organic lesions of pancreatic islet tissues and diminished insulin secretion, thereby accelerating the progression of diabetes mellitus (DM).

Methods

Sprague-Dawley (SD) rats were induced with periodontitis (PD), type 2 diabetes mellitus (T2DM), or the combination of T2DM and PD (DP) through a high-sugar/high-fat diet and ligation of the tooth neck with silk thread. Alveolar bone resorption was assessed using Micro-CT, blood glucose levels were measured with a blood glucose meter, pancreatic tissue pathology was examined through HE staining, and the expression of autophagy-related proteins Beclin1 and LC3II/LC3I was analyzed using Western blotting.

Results

Micro-CT results revealed more pronounced alveolar bone resorption and root bifurcation exposure in the PD and DP groups compared to the control group, with the DP group exhibiting the most severe condition. HE staining demonstrated the formation of periodontal pockets, severe alveolar bone destruction, and abnormal pancreatic islet tissue morphology in the PD and DP groups. The serum levels of IL-6, TNF-α, and IL-1β increased sequentially in the control, DM, PD, and DP groups (P < 0.05). Relative expressions of GCK and GLUT-2 mRNA decreased in the PD group compared to the control group (P > 0.05), while the mRNA expressions in the DP and DM groups increased (P < 0.05), with the DP group exhibiting higher levels than the DM group (P < 0.05). Western blot results indicated increased expression levels of autophagy proteins Beclin1 and LC3II/LC3I in the DM and DP groups compared to the control group (P < 0.05), with the DP group exhibiting higher levels than the DM group (P < 0.05).

Conclusion

The findings demonstrate that periodontal inflammatory factors may promote the enhancement of pancreatic cell autophagy in diabetic rats.

Bifidobacterium animalis subspecies lactis HN019 can reduce the sequelae of experimental periodontitis in rats modulating intestinal parameters, expression of lipogenic genes, and levels of hepatic steatosis

OBJECTIVE

To determine whether Bifidobacterium animalis subspecies lactis HN019 (B. lactis HN019) can reduce the sequelae of experimental periodontitis (EP) in rats modulating systemic parameters.

BACKGROUND

This study evaluated the effects of probiotic therapy (PROB) in the prevention of local and systemic damage resulting from EP.

METHODS

Forty-eight rats were allocated into four groups: C (control), PROB, EP, and EP-PROB. PROB (1 × 1010  CFU/mL) administration lasted 8 weeks and PE was induced on the 7th week by placing ligature on the animals' lower first molars. All animals were euthanized in the 9th week of the experiment. Biomolecular analyses, RT-PCR, and histomorphometric analyses were performed. The data obtained were analyzed statistically (ANOVA, Tukey, p < .05).

RESULTS

The EP group had higher dyslipidemia when compared to the C group, as well as higher levels of insulin resistance, proteinuria levels, percentages of systolic blood pressure, percentage of fatty hepatocytes in the liver, and expression of adipokines was up-regulated (LEPR, NAMPT, and FABP4). All these parameters (except insulin resistance, systolic blood pressure, LEPR and FABP4 gene expression) were reduced in the EP-PROB group when compared to the EP group. The EP group had lower villus height and crypt depth, as well as a greater reduction in Bacteroidetes and a greater increase in Firmicutes when compared to the EP-PROB group. Greater alveolar bone loss was observed in the EP group when compared to the EP-PROB group.

CONCLUSION

Bifidobacterium lactis HN019 can reduce the sequelae of EP in rats modulating intestinal parameters, attenuating expression of lipogenic genes and hepatic steatosis.

Association between metabolic syndrome and periodontitis: The role of lipids, inflammatory cytokines, altered host response, and the microbiome

Periodontitis has been associated with many systemic diseases and conditions, including metabolic syndrome. Metabolic syndrome is a cluster of conditions that occur concomitantly and together they increase the risk of cardiovascular disease and double the risk of type 2 diabetes. In this review, we focus on the association between metabolic syndrome and periodontitis; however, we also include information on diabetes mellitus and cardiovascular disease, since these two conditions are significantly intertwined with metabolic syndrome. With regard to periodontitis and metabolic syndrome, to date, the vast majority of studies point to an association between these two conditions and also demonstrate that periodontitis can contribute to the development of, or can worsen, metabolic syndrome. Evaluating the effect of metabolic syndrome on the salivary microbiome, data presented herein support the hypothesis that the salivary bacterial profile is altered in metabolic syndrome patients compared with healthy patients. Considering periodontitis and these three conditions, the vast majority of human and animal studies point to an association between periodontitis and metabolic syndrome, diabetes, and cardiovascular disease. Moreover, there is evidence to suggest that metabolic syndrome and diabetes can alter the oral microbiome. However, more studies are needed to fully understand the influence these conditions have on each other.

Impact of endodontic and periodontal diseases and treatments on the aorta and liver of obese and non-obese rats

AIM

To evaluate the impact of the presence and treatment of periodontal disease (PD) and apical periodontitis (AP) on the aorta and liver of obese and non-obese rats.

METHODOLOGY

One hundred and forty Wistar rats were divided into two groups, according to the diet administered: normal diet (-n), without obesity; and cafeteria diet (-c), with induced obesity. These groups were divided into seven subgroups according to the specific experimental protocols: naïve control (NC); AP; AP with treatment (APt); PD; PE with treatment (PDt); AP and PD (APPD); and AP and PD with treatment (APPDt). AP and PD lesions were induced for four weeks. Four weeks after treatments, the animals were euthanatized, and the aorta and liver were dissected for histological evaluation. For the comparison of the thickness of the aorta between groups, the Kruskal-Wallis test was used, followed by the Mann-Whitney test. For the analysis of other variables related to the aorta and liver outcomes, logistic regression was carried out.

RESULTS

Both PD and AP were associated with the development of histological alterations in the aortic arch, with no significant difference between obese and non-obese animals (p = .17). The aorta thickness was increased significantly (p < .05) with the combination of PD and AP in obese rats (APPDt-c group) compared with the other groups (NC-n, APt-n, APt-c and AP-c). The logistic regression models revealed that the untreated (OR = 7.78; 95%CI = 2.4-25) and treated (OR = 2.9; 95%CI = 1.0-8.4) groups were significantly more likely to have endothelial alterations compared with the control groups (p = .002). Obesity (OR = 16.5; 95%CI = 3.4-81.3) was the only predictor variable of liver steatosis (p < .001).

CONCLUSION

Histological alterations in the aortic arch of obese and non-obese rats were observed in the presence of periodontal disease and apical periodontitis. The combination of PD and AP increased the aorta thickness in obese rats. A reduction of vascular endothelial lesions was observed with the treatments of PD and AP.

Impact of hyperglycemia and treatment with metformin on ligature-induced bone loss, bone repair and expression of bone metabolism transcription factors

This study evaluated the influence of type 2 diabetes mellitus on bone loss, bone repair and cytokine production in hyperglycemic rats, treated or not with metformin. The animals were distributed as follow: Non-Hyperglycemic (NH), Non Hyperglycemic with Ligature (NH-L), Treated Non Hyperglycemic (TNH), Treated Non Hyperglycemic with Ligature Treated (TNH-L), Hyperglycemic (H), Treated Hyperglycemic (TH), Hyperglycemic with Ligature (H-L), Treated Hyperglycemic with Ligature (TH-L). At 40th day after induction of hyperglycemia, the groups NH-L, TNH-L, H-L, TH-L received a ligature to induce periodontitis. On the 69th, the TNH, TNH-L, TH, TH-L groups received metformin until the end of the study. Bone repair was evaluated at histometric and the expression levels of Sox9, RunX2 and Osterix. Analysis of the ex-vivo expression of TNF-α, IFN-γ, IL-12, IL-4, TGF-β, IL-10, IL-6 and IL-17 were also evaluated. Metformin partially reverse induced bone loss in NH and H animals. Lower OPG/RANKL, increased OCN and TRAP expression were observed in hyperglycemic animals, and treatment with metformin partially reversed hyperglycemia on the OPG/RANKL, OPN and TRAP expression in the periodontitis. The expression of SOX9 and RunX2 were also decreased by hyperglycemia and metformin treatment. Increased ex vivo levels of TNF-α, IL-6, IL-4, IL-10 and IL-17 was observed. Hyperglycemia promoted increased IL-10 levels compared to non-hyperglycemic ones. Treatment of NH with metformin was able to mediate increased levels of TNF-α, IL-10 and IL-17, whereas for H an increase of TNF-α and IL-17 was detected in the 24- or 48-hour after stimulation with LPS. Ligature was able to induce increased levels of TNF-α and IL-17 in both NH and H. This study revealed the negative impact of hyperglycemia and/or treatment with metformin in the bone repair via inhibition of transcription factors associated with osteoblastic differentiation.

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

The bidirectional relationship between diabetes mellitus (DM) and periodontal disease has drawn great attention; however, the mechanisms underlying their association remain unclear. In this study, we aimed to develop a rhesus monkey model of diabetic periodontitis and explore the potential mechanisms by which DM affects the progression of periodontal disease. Three healthy rhesus monkeys were selected as the control group. Five streptozotocin-induced diabetic rhesus monkeys were chosen as the experimental group. Ligature placement was used to induce periodontitis. The changes in the levels of advanced glycation end products (AGEs), beta-defensin-3 (BD-3), and interleukin-17 (IL-17) were measured using enzyme-linked immunosorbent assays (ELISA) and real-time reverse transcription polymerase chain reaction (RT-PCR) at different stages during disease progression. Periodontitis was confirmed by clinical assessment, radiographic images, and histological examination. Significant changes in the levels of AGEs and BD-3 in serum were observed at the periodontitis stage in diabetic rhesus monkeys ( P < 0.05). The expression of BD-3 mRNA in the gingiva of diabetic group at baseline was significantly high ( P < 0.05). Diabetic monkeys exhibited significantly enhanced IL-17 mRNA expression at the periodontitis stage ( P < 0.05). Our findings indicated that the rhesus monkey can serve as an ideal model for exploring the pathogenesis of diabetic periodontitis, and the hyperglycemic environment may accelerate inflammatory response and weaken the defense system in periodontal tissues. Impact statement The mechanism underlying the association between diabetes mellitus (DM) and periodontal disease is not yet fully understood. Hence, there is a need to establish animal models to reveal the effect of DM on the pathogenesis of periodontitis. In this study, we explored the appropriate methods for inducing periodontitis and shortening the modeling time in rhesus monkeys, to investigate the pathogenesis of diabetic periodontitis and develop innovative therapies. Our results suggest that a hyperglycemic environment might lead to the destruction of periodontal tissues by accelerating inflammatory response and weakening the defense system in periodontal tissues. Therefore, this study has significant treatment implications regarding the regulation of the immune response against periodontal diseases in patients with DM.

Long-term Hyperglycemia Naturally Induces Dental Caries but Not Periodontal Disease in Type 1 and Type 2 Diabetic Rodents

Periodontal disease (PD) in patients with diabetes is described as the sixth complication of diabetes. We have previously shown that diabetes increases dental caries, and carious inflammation might have a strong effect on the adjacent periodontal tissue in diabetic rodent models. However, the possibility that hyperglycemia may induce PD in diabetic animals could not be completely eliminated. The goal of this study was to confirm the presence of PD in diabetic animal models by preventing carious inflammation with fluoride administration. F344 rats injected with alloxan (type 1 diabetic model) and db/db mice (type 2 diabetic model) were given either tap water alone or tap water containing fluoride. A cariostatic effect of fluoride was evident in the diabetic animals. Meanwhile, fluoride treatment drastically attenuated periodontal inflammation in addition to preventing dental caries. Furthermore, with fluoride treatment, periodontitis was notably nonexistent in the periodontal tissue surrounding the normal molars, whereas the caries-forming process was clearly observed in the teeth that were enveloped with persistent periodontitis, suggesting that enhanced periodontal inflammation might have been derived from the dental caries in the diabetic rodents rather than from the PD. In conclusion, long-term hyperglycemia naturally induces dental caries but not PD in type 1 and type 2 diabetic rodents.

Blockade of RAGE in Zucker obese rats with experimental periodontitis

BACKGROUND AND OBJECTIVE

Periodontitis and type 2 diabetes mellitus (T2D) are two interrelated chronic diseases. Periodontitis is more prevalent in patients with T2D than in healthy subjects, and studies indicate that periodontitis impacts the metabolic control of patients with T2D. Hyperglycemia in T2D leads to the formation of advanced glycation end-products (AGEs). Binding of AGEs to the receptor of AGE (RAGE) elicits an increased inflammatory response that may be a key modulator linking the two diseases. The present study aimed to elucidate the effect of blocking the RAGE on the interrelationship between periodontitis and T2D in a rat model of both diseases.

MATERIAL AND METHODS

Zucker obese rats (HsdHlr:ZUCKER-Lepr ^fa/fa ) and their lean littermates were divided into five treatment groups, with and without periodontitis. Monoclonal anti-RAGE IgG₃ were injected into the rats three times a week. The diabetic state was evaluated by oral glucose tolerance tests (OGTTs), the homeostasis model assessment (HOMA), concentration of free fatty acids and repeated measurements of blood glucose. Markers of systemic inflammation, including interleukin (IL)-1β, IL-6 and tumor necrosis factor α, were evaluated in plasma. Kidney complications were evaluated by quantitative real-time PCR, the creatinine clearance rate, the albumin excretion rate and kidney hypertrophy. Periodontitis was evaluated by morphometric registration of alveolar bone loss and radiographic recording of bone support.

RESULTS

The diabetic state was improved by antibody treatment for 4 wk, resulting in a lower area under the glucose concentration curve during OGTTs, lower insulin levels and a lower HOMA. Furthermore, the antibody treatment resulted in milder kidney complications, as evaluated by measuring the albumin excretion rate and the kidney weight. There was no impact of periodontal inflammation on the level of complications. Periodontal bone support was influenced by diabetes, but the altered diabetic status as a result of treatment with anti-RAGE Ig had no effect on periodontitis.

CONCLUSION

In this study, treatment with anti-RAGE IgG₃ resulted in improved glucose tolerance and attenuated renal complications. However, no effect was observed on the diabetes-associated periodontitis in Zucker obese rats. Furthermore, periodontitis had no effect on diabetic markers or renal complications. Therefore, activation of RAGE is important in the development of T2D.

Effect of oral hygiene maintenance on HbA1c levels and peri-implant parameters around immediately-loaded dental implants placed in type-2 diabetic patients: 2 years follow-up

OBJECTIVE

The aim of the present 2-year follow-up study was to assess the effect of oral hygiene maintenance on hemoglobin Alc (HbA1c) levels and peri-implant parameters around immediately-loaded dental implants placed in type-2 diabetic patients with varying glycemic levels.

MATERIAL AND METHODS

Ninety-one individuals were divided into three groups. In group 1, 30 systemically healthy individuals were included (HbA1c < 6%). Patients in group 2 and 3, comprised of 30 patients with T2DM (HbA1c 6.1-8%); and 31 patients with T2DM (HbA1c 8.1-10%) respectively. In all groups, patients received immediately loaded bone level implants. All participants were enrolled in a 6 monthly periodontal/peri-implant maintenance program. Peri-implant bleeding on probing (BOP), probing depth (PD), and marginal bone loss (MBL) were measured at 6, 12, and 24 months of follow-up.

RESULTS

Mean preoperative HbA1c levels in patients in groups 1, 2, and 3 were 4.5%, 6.8%, and 8.7% respectively. In group-1, there was no significant difference in HbA1c levels at all follow-up durations. Among patients in groups 2 and 3, there was a significant decrease in HbA1c levels at 24-months follow-up than 6-months follow-up. At 6 months follow-up, BOP, PD, and MBL were significantly higher among patients in group-3 than group-1. At 12 and 24 months follow-up, there was no significant difference in BOP, PD, and MBL in all groups.

CONCLUSIONS

Oral hygiene maintenance reduces hyperglycemia and peri-implant inflammatory parameters around immediately loaded dental implants placed in type 2 diabetic patients.

Effects of TNF-α blocking on experimental periodontitis and type 2 diabetes in obese diabetic Zucker rats

OBJECTIVE

Tumour necrosis factor α (TNF-α) is considered a key signalling modulator in the pathogenesis of both periodontitis (PD) and type 2 diabetes mellitus (DM2). This study aims at elucidating the effect of TNF-α blocking on the interplay between PD and DM2.

METHODS

Obese diabetic Zucker rats and their lean littermates were divided into five treatment groups with or without periodontitis. Anti-TNF-α treatment was provided with Etanercept injections. Diabetic state was evaluated by oral glucose tolerance test, the homeostatic model assessment, free fatty acids and blood glucose. Systemic inflammation was assessed by measurement of interleukin (IL)-1β, IL-6 and TNF-α in plasma. Kidney complications were evaluated by real-time rtPCR, creatinine clearance rate, urinary albumin excretion and increase in weight. PD was evaluated by registration of alveolar bone level.

RESULTS

After 4 weeks the diabetic state was modified by Etanercept treatment with lower insulin levels and lower homeostatic model assessment. Furthermore, while kidney complications were reduced by Etanercept treatment, PD had no effect. PD was influenced by diabetic state, but the impact was attenuated by Etanercept treatment.

CONCLUSION

In this study anti-TNF-α treatment improved glucose tolerance and compensated for the increased periodontal disease in obese diabetic Zucker. PD did not influence diabetic parameters assessed including complications of the rats kidneys.

Alveolar bone protective and hypoglycemic effects of systemic propolis treatment in experimental periodontitis and diabetes mellitus

The aim of this study was to evaluate the efficacy of the anti-inflammatory effects of propolis on the systemic and local effects on experimental periodontitis and diabetes. Fifty-six Wistar rats were divided into seven groups: (1) negative-control (NC), (2) periodontitis (P), (3) diabetes (D), (4) diabetes+periodontitis (DP), (5) periodontitis+propolis (P-Pro), (6) diabetes+propolis (D-Pro), and (7) diabetes+periodontitis+propolis (DP-Pro). Periodontitis was induced by ligature placement and diabetes was induced by streptozotocin injection. Propolis (Pro) was administrated by oral gavage (100 mg/kg/day). On day 21, plasma was obtained for analysis and alveolar bone level was evaluated using histomorphometric analysis. Compared to NC the final blood glucose levels for D-Pro was not significantly different (P=.052), however, D, DP, and DP-Pro were significantly different. There were no statistically significant differences in blood glucose concentrations between P and P-Pro, between D and D-Pro, and between DP and DP-Pro. All groups showed significantly more alveolar bone loss compared with NC. A significant difference in bone loss was found between P and P-Pro, and DP and DP-Pro, however there was no difference between D and D-Pro. Plasma interleukin 1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and matrix metalloproteinase-8 (MMP-8) levels were not significantly different among groups. In conclusion, propolis reduced fasting blood glucose levels in diabetes. In addition, propolis might be beneficial as an adjunct treatment of diabetes associated periodontitis and periodontitis without diabetes.

Therapeutic effect of TSG-6 engineered iPSC-derived MSCs on experimental periodontitis in rats: a pilot study

Background

We derived mesenchymal stem cells (MSCs) from rat induced pluripotent stem cells (iPSCs) and transduced them with tumor necrosis factor alpha-stimulated gene-6 (TSG-6), to test whether TSG-6 overexpression would boost the therapeutic effects of iPSC-derived MSCs in experimental periodontitis.

Methods

A total of 30 female Sprague-Dawley (SD) rats were randomly divided into four groups: healthy control group (Group-N, n = 5), untreated periodontitis group (Group-P, n = 5), iPS-MSCs-treated and iPSC-MSCs/TSG-6-treated periodontitis groups (Group-P1 and P2, n = 10 per group). Experimental periodontitis was established by ligature and infection with Porphyromonas gingivalis around the maxillae first molar bilaterally. MSC-like cells were generated from rat iPSCs, and transducted with TSG-6. iPSC-MSCs or iPSC-MSCs/TSG-6 were administrated to rats in Group-P1 or P2 intravenously and topically, once a week for three weeks. Blood samples were obtained one week post-injection for the analysis of serum pro-inflammatory cytokines. All animals were killed 3 months post-treatment; maxillae were then dissected for histological analysis, tartrate-resistant acid phosphatase (TRAP) staining, and morphological analysis of alveolar bone loss.

Results

Administration of iPSC-MSC/TSG-6 significantly decreased serum levels of IL-1β and TNF-α in the Group-P2 rats (65.78 pg/ml and 0.56 pg/ml) compared with those in Group-P (168.31 pg/ml and 1.15 pg/ml respectively) (p<0.05). Both alveolar bone loss and the number of TRAP-positive osteoclasts showed a significant decrease in rats that received iPSC-MSC/TSG-6 treatment compared to untreated rats in Group-P (p<0.05),

Conclusions

We demonstrated that overexpression of TSG-6 in rat iPSC-derived MSCs were capable of decreasing inflammation in experimental periodontitis and inhibiting alveolar bone resorption. This may potentially serve as an alternative stem-cell-based approach in the treatment and regeneration of periodontal tissues.

Assessment of Alloxan-Induced Diabetic Rats as a Periodontal Disease Model Using a Selective Cyclooxygenase (COX)-2 Inhibitor

Several recent studies have reported that alloxan-treated rats with long-term hyperglycemia can develop naturally occurring periodontal disease (PD). Our previous studies detected dental caries in the same model. Therefore, these two lesions of different etiologies are expected to occur concurrently. In this study, we evaluated the use of diabetic rats as a PD model by employing a selective COX-2 inhibitor reported to be effective against PD. Six-week-old female F344 rats were divided into 3 groups: intact rats (control), alloxan-induced diabetic rats fed a standard diet (AL) and alloxan-induced diabetic rats fed a diet containing 0.01% etodolac (AL+Et). The animals were euthanized at 26 weeks of age, and their oral tissues were examined histopathologically. Gingivitis, marginal periodontitis and alveolar bone resorption were markedly enhanced along with dental caries in the AL group compared with the control group. However, the COX-2 inhibitor had no effect on periodontal inflammation in the AL+Et group. In addition, in the AL group, periodontitis was notably nonexistent around the normal molars, and gingivitis was scarcely worse than that in the control group. In the diabetic rats, the progression of periodontal inflammation was closely correlated with the severity of adjacent dental caries, and marginal periodontitis was frequently continuous with apical periodontitis. In conclusion, an alloxan-induced diabetic rat is not a model of PD but of dental caries. It is probable that in this model, hyperglycemia may enable crown caries to progress to apical periodontitis, while the associated inflammation may rostrally expand to surrounding periodontal tissue.

Effect of nonsurgical periodontal therapy (with or without oral doxycycline delivery) on glycemic status and clinical periodontal parameters in patients with prediabetes: a short-term longitudinal randomized case-control study

OBJECTIVE

The aim of the present short-term longitudinal randomized case-control study was to assess the effect of nonsurgical periodontal therapy (NSPT) (with and without oral doxycycline delivery) on glycemic status and clinical periodontal parameters in patients with prediabetes.

MATERIAL AND METHODS

Sixty-six patients with prediabetes and periodontal disease were included. Characteristics of the study cohort (age, gender, socioeconomic status [SES] education status, duration of prediabetes, and type of treatment adopted for prediabetes management) were recorded. Patients were randomly divided into two groups (33 patients/group). In group 1, scaling and root planing (SRP) was performed, and in group-2, patients underwent SRP and oral doxycycline (100 mg) administration once daily for 15 days. In each group, the following parameters were investigated at baseline and after 3 months: (a) fasting blood glucose level (FBGL), (b) hemoglobin A1c (HbA1c), and (c) periodontal parameters (plaque index [PI], bleeding on probing [BOP], probing depth [PD], and clinical attachment loss [AL]). Statistical analysis was performed using Student's t test.

RESULTS

There was no significant difference in age, gender, SES, education status, and duration and treatment of prediabetes among individuals in groups 1 and 2. Three months post-NSPT, FBGL and HbA1c were significantly reduced among patients in group 1 (P < 0.05) and group 2 (P < 0.05) compared to baseline. Three months post-NSPT, PI (P < 0.05), BOP (P < 0.05), and PD (P < 0.05) were significantly reduced among patients in group 1 (P < 0.05) and group 2 (P < 0.05) compared to baseline. There was no difference in clinical AL between the groups after 3 months of NSPT.

CONCLUSION

NSPT (with and without oral doxycycline delivery) reduces hyperglycemia and periodontal inflammation in patients with prediabetes.

Glycemic control with insulin prevents progression of dental caries and caries-related periodontitis in diabetic WBN/KobSlc rats

We have previously reported that dental caries progress in spontaneously and chemically induced diabetic rodent models. The aim of this study was to clarify the relationship between hyperglycemia and dental caries by evaluating the preventive effect of glycemic control with insulin on the progression of the lesions in diabetic rats. Male WBN/KobSlc rats aged 15 weeks were divided into groups of spontaneously diabetic rats (intact group), spontaneously diabetic rats with insulin treatment (INS group), alloxan-induced prolonged diabetic rats (AL group), and alloxan-induced prolonged diabetic rats with insulin treatment (AL + INS group). The animals were killed at 90 weeks of age, and their oral tissue was examined. Dental caries and periodontitis were frequently detected in the intact group, and the lesions were enhanced in the AL group (in which there was an increased duration of diabetes). Meanwhile, glycemic control with insulin reduced the incidence and severity of dental caries and periodontitis in the INS group, and the effects became more pronounced in the AL + INS group. In conclusion, glycemic control by insulin prevented the progression of dental caries and caries-related periodontitis in the diabetic rats.

Effects of non-surgical periodontal treatment on clinical response, serum inflammatory parameters, and metabolic control in patients with type 2 diabetes: a randomized study

BACKGROUND

Scientific evidence on the effects of chronic periodontitis on diabetes mellitus remains inadequate and inconclusive. This intervention study is designed to evaluate the effects of periodontal treatment on clinical response, systemic inflammatory parameters, and metabolic control in patients with Type 2 diabetes.

METHODS

A total of 134 patients were randomly allocated into two treatment groups and one control group. Treatment group 1 underwent non-surgical periodontal treatment at baseline and additional subgingival debridement at the 3-month follow-up. Patients in treatment group 2 received non-surgical periodontal treatment and supragingival prophylaxis at the 3-month follow-up, and those in the control group received no intervention throughout the study. All participants were reexamined at 1.5, 3, and 6 months after initial treatment. At each visit, clinical periodontal examinations were conducted and blood samples were taken to evaluate high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor-α (TNF-α), glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and lipid profiles.

RESULTS

Both treatment groups had a significantly lower hsCRP level after periodontal therapy (P <0.05). Although HbA1c declined significantly in treatment group 2 (P <0.05), the intergroup difference for HbA1c, FPG, TNF-α, and lipid profiles was not statistically significant after therapy (P >0.05).

CONCLUSIONS

Non-surgical periodontal treatment can effectively improve periodontal and circulating inflammatory status. Despite a lack of strong evidence, trends in some results support improved glycemic control after periodontal treatment in patients with diabetes.

Involvement of toll-like receptor 4 in alveolar bone loss and glucose homeostasis in experimental periodontitis

BACKGROUND AND OBJECTIVE

There is general agreement that certain fatty acids and lipopolysaccharides (LPS) promote inflammation through toll-like receptor 4 (TLR4), and that inflammation promotes insulin resistance. We therefore hypothesized that mice with periodontitis and a TLR4 loss-of-function (LOF) mutation fed a high-fat (HF) diet would develop improved glucose homeostasis compared with wild-type (WT) animals with periodontitis fed a HF diet.

MATERIAL AND METHODS

Wild-type and TLR4 mutant mice fed a HF diet were divided into four groups (n = 6/group): WT; WT with periodontitis (WT/P); mutant (Mut); and mutant with periodontitis (Mut/P). Periodontitis was induced by placing LPS soaked ligatures around maxillary second molars. Fasting insulin and glucose levels were measured weekly for 10 wk. Glucose tolerance was evaluated at baseline (week 1) and at 9 wk. Insulin signaling (phosphorylation of Akt) and tumor necrosis factor-α (TNF-α) mRNA levels in liver were determined when the mice were killed at week 10.

RESULTS

Mut/P mice developed less alveolar bone loss compared with WT/P mice (p < 0.05). Fasting glucose levels were improved after 8 wk of feeding a HF diet (weeks 9 and 10) in Mut/P mice compared with Mut, WT and WT/P mice (p < 0.05). Glucose tolerance was impaired in all groups compared with baseline (p < 0.05), except for the Mut/P group. Insulin signaling was improved (p < 0.05), and expression of TNF-α was decreased (p < 0.05) in the liver of Mut/P mice compared with the liver of WT/P mice.

CONCLUSION

The TLR4 LOF mutation partially protects against alveolar bone loss and improves glucose homeostasis in mice with periodontitis fed a HF diet.

Dental caries and caries-related periodontitis in type 2 diabetic mice

Diabetic patients are predisposed to periodontal disease as well as dental caries; however, there are contradictory reports about the possible association between dental caries and diabetes. Thus, the authors set out to determine whether diabetes affects onset of dental caries and periodontal disease and to clarify whether dental caries and periodontal disease are associated with each other in diabetic db/db mice. Oral tissue was examined from 68 male mice (diabetic db/db and nondiabetic db/+; aged 20, 30, 40, and 50 weeks) and 20 female mice (db/db and db/+; aged 50 weeks). Macroscopically, caries were seen developing in the diabetic mice by 20 weeks of age. The number of teeth with dental lesions increased with age in the db/db mice at a significantly higher incidence than that of db/+ mice. Histologically, dental caries were detected in 30 of 120 molars in 17 of 20 db/db mice at 50 weeks of age and in 4 of 108 molars in 4 of 18 db/+ mice of the same age. The severity of dental caries in db/db mice was significantly higher than it was in db/+ mice. Dental caries were a primary change that led to bacterial gingivitis and pulpitis. These lesions spread to the dental root and periodontal connective tissue through the apical foramen. Apical periodontitis was more frequent and severe when occurring in close association with dental caries. In conclusion, there is a strong relationship between diabetes and dental caries, but in this model, it is highly probable that the onset of periodontal disease was a secondary change resulting from dental caries.

Saturated fatty acids enhance osteoclast survival

Hyperlipidemia and marrow fat are associated with lowering bone density in vivo, suggesting that lipid contributes to bone loss. Using bone marrow-derived macrophages, we investigated the effect of saturated fatty acids (SFA) on osteoclastogenesis. The level of free fatty acids and adiposity in bone marrow was significantly elevated in obese mice. SFA increased osteoclast (OC) survival by preventing apoptosis. SFA caused the production of MIP-1alpha and led to activation of nuclear factor (NF)-kappaB in the OC. The absence of Toll-like receptor 4 (TLR4) or myeloid differentiation factor 88 (MyD88) abolished the survival effect of SFA on OC.

Anti-NGF treatment reduces bone resorption in periodontitis

Periodontitis is characterized by periodontal tissue destruction, including the alveolar bone. One of its critical components is the release of pro-inflammatory neuropeptides from sensory nerve endings innervating the periodontium. Since nerve growth factor (NGF) has been reported to up-regulate neuropeptides in sensory neurons, we hypothesized that it would be increased in ligature-induced periodontitis in rats, and that systemic NGF neutralization would reduce the periodontitis-associated alveolar bone resorption. Real-time PCR analysis disclosed a statistically significant time-dependent up-regulation of NGF mRNA in gingiva during 2 weeks of periodontitis. Interestingly, NGF up-regulation was also detected in the contralateral gingiva. In addition, immunohistochemistry of trigeminal ganglion neurons innervating the gingivomucosa demonstrated increased expression of TrkA receptor for NGF. Systemic anti-NGF treatment during periodontitis significantly reduced interleukin-1beta expression in gingiva and bilateral alveolar bone resorption. This suggests that NGF promotes periodontal inflammation and implicates a possible use of anti-NGF treatment in periodontitis.

Effect of periodontitis on insulin resistance and the onset of type 2 diabetes mellitus in Zucker diabetic fatty rats

BACKGROUND

Studies indicate that an association exists between periodontitis and type 2 diabetes mellitus (T2DM) and/or obesity, with chronic inflammation hypothesized as the common denominator. The purpose of this study was to determine the causal effect of periodontitis and the concomitant impact of diet on the onset of insulin resistance (IR) and T2DM using a rat model system that simulates human obesity and T2DM.

METHODS

Twenty-eight, 5-week-old female Zucker diabetic fatty (ZDF, fa/fa) rats were divided into four groups of seven animals: high-fat fed-periodontitis (HF/P), high-fat fed-no periodontitis (HF/C), low-fat fed-periodontitis (LF/P), and low-fat fed-no periodontitis (LF/C). Periodontitis was induced by ligature placement. Fasting plasma insulin and glucose levels were measured, and glucose tolerance tests were performed to assess glucose homeostasis, IR, and the onset of T2DM. The level of tumor necrosis factor-alpha (TNF-alpha), leptin, triglycerides, and free fatty acids were determined in week 13 at sacrifice.

RESULTS

HF/P rats developed more severe IR compared to HF/C rats (P <0.01) and LF/P or LF/C rats (P <0.001) as measured by fasting insulin levels and homeostasis model assessment analysis. The onset of severe IR occurred approximately 3 weeks earlier in HF/P rats compared to HF/C rats. HF/P rats developed impaired (110 to 125 mg/dl) and frank fasting hyperglycemia (>125 mg/dl) 2 weeks earlier than HF/C rats. There was no difference in the severity and onset of IR and T2DM between LF/P and LF/C rats. The level of TNF-alpha was significantly higher in HF/P rats compared to HF/C rats (P <0.01).

CONCLUSION

Periodontitis accelerated the onset of severe IR and impaired glucose homeostasis in high-fat fed ZDF rats.

Alloxan-induced diabetes triggers the development of periodontal disease in rats

Background

Periodontal disease in diabetic patients presents higher severity and prevalence; and increased severity of ligature-induced periodontal disease has been verified in diabetic rats. However, in absence of aggressive stimuli such as ligatures, the influence of diabetes on rat periodontal tissues is incompletely explored. The aim of this study was to evaluate the establishment and progression of periodontal diseases in rats only with diabetes induction.

Methodology/Principal Findings

Diabetes was induced in Wistar rats (n = 25) by intravenous administration of alloxan (42 mg/kg) and were analyzed at 1, 3, 6, 9 and 12 months after diabetes induction. The hemimandibles were removed and submitted to radiographical and histopathological procedures. A significant reduction was observed in height of bone crest in diabetic animals at 3, 6, 9 and 12 months, which was associated with increased numbers of osteoclasts and inflammatory cells. The histopathological analyses of diabetic rats also showed a reduction in density of collagen fibers, fibroblasts and blood vessels. Severe caries were also detected in the diabetic group.

Conclusions/Significance

The results demonstrate that diabetes induction triggers, or even co-induces the onset of alterations which are typical of periodontal diseases even in the absence of aggressive factors such as ligatures. Therefore, diabetes induction renders a previously resistant host into a susceptible phenotype, and hence diabetes can be considered a very important risk factor to the development of periodontal disease.

Inverse association between number of teeth and left ventricular mass in women

OBJECTIVES

Recently, we have demonstrated a sex-specific inverse association between the number of teeth and hypertension. Left ventricular hypertrophy is a major cardiac sequel of hypertension. With the present study we sought to investigate whether there is also an inverse association between the number of teeth and left ventricular mass (LVM).

METHODS

We used data from 1913 subjects (1036 women and 877 men) who were recruited for the population-based Study of Health in Pomerania (SHIP). The number of teeth, with the exception of the third molars, was counted in the full mouth. LVM was determined echocardiographically. Multivariable analyses were adjusted for major confounders.

RESULTS

Women with fewer teeth had higher values for LVM than women with more teeth. This association was stable when controlled for major confounders. In the full model, edentulous women had an adjusted LVM of 178.4 g [95% confidence interval (CI) 170.4, 186.3 g] while women with 24-28 teeth had an adjusted LVM of 164.8 g (95% CI 156.8, 172.9 g; P < 0.01). In men, no such differences were observed.

CONCLUSIONS

We conclude that there is an association between the number of teeth and LVM in women aged 45 years or older. In women, these findings further explain why poor oral health predicts all-cause and circulatory mortality. Further research in young, low-risk populations is needed to explore this association in men.

Relationship Between Periodontitis and Diabetes: Lessons From Rodent Studies

BACKGROUND

A great amount of investigations have provided evidence that both type 1 and type 2 diabetes increase the risk and severity of periodontitis; several alterations in the diabetic periodontium are likely to be involved. Conversely, periodontitis has been shown to have an impact on diabetes, although less evidence is available on the underlying mechanisms. The association between periodontitis and diabetes has been discussed in several reviews over the past years; however, none has focused on the use and contribution of rodent models.

METHODS

This review describes the most commonly used rodent models of diabetes, periodontitis, and the association between the two diseases. Further, we summarize the influence of diabetes in the periodontium as well as the effect of periodontitis on diabetes status with special focus on evidence from experimental studies.

RESULTS

Rodent studies have confirmed human findings and further increased our knowledge on the alterations in the diabetic periodontium. On the other hand, few rodent investigations have explored the consequences of periodontitis for diabetes. Their results clearly indicate that periodontitis can become a health hazard not only for diabetes but also for prediabetes; the exact mechanisms are still to be unraveled.

CONCLUSIONS

Findings from rodent studies have been useful in increasing our understanding of periodontitis, diabetes, and their association and hold great promise for future investigations given the wide variety of possibilities for testing biologic hypotheses.

Periodontitis is associated with aggravation of prediabetes in Zucker fatty rats

BACKGROUND

Prediabetes is part of the natural history of type 2 diabetes. Few human studies have addressed the relationship between periodontitis and prediabetes. The Zucker fatty rat (ZFR) is a known model of prediabetes, characterized by hyperinsulinemia, dyslipidemia, and moderate hypertension. The aim of the present study was to investigate whether periodontitis affects the prediabetic state of ZFRs.

METHODS

Male adult ZFRs (fa/fa; N = 24) and their lean littermates (+/fa; N = 24) were studied. Periodontitis was induced with ligatures in half of the ZFRs and lean rats, whereas the other half served as controls. After 4 weeks, body weight, food intake, glucose tolerance, insulin resistance, free fatty acids, cytokines, and alveolar bone loss were recorded.

RESULTS

ZFRs with periodontitis presented increased glucose intolerance (P = 0.03) and a slight increase in fasting glucose from initial to final evaluation, as detected through paired analysis (P = 0.03). Among lean rats, those with periodontitis presented higher final glucose intolerance than those without periodontitis (P = 0.01). Furthermore, periodontitis in lean rats was associated with increased fasting glucose, insulin, and insulin resistance, as evaluated through paired analysis (P = 0.003, P = 0.008, and P = 0.001, respectively). Regarding alveolar bone analysis, ZFRs with periodontitis demonstrated significantly more bone loss compared to lean rats with periodontitis (P <0.001).

CONCLUSIONS

Prediabetes worsened periodontitis, and periodontitis, in turn, was associated with deterioration of glucose metabolism in ZFRs, suggesting a progress toward diabetes. Furthermore, periodontitis also affected glucose regulation in lean rats.