Oxidative stress causes alveolar bone loss in metabolic syndrome model mice with type 2 diabetes

Green tea extract as a local drug therapy on periodontitis patients with diabetes mellitus: A randomized case-control study

Background:

The green tea extract is a naturally occurring product having beneficial effects that counteract with the pathobiological features of periodontitis and diabetes mellitus. Hence, the present study was aimed at incorporation of green tea extract into hydroxylpropyl methylcellulose and investigates its efficacy in chronic periodontitis patients associated with and without diabetes mellitus.

Materials and Methods:

For the in vitro study, formulation of green tea strips and placebo strips, and analysis of drug release pattern from the green tea strips at different time intervals were performed. For the in vivo study, 50 patients (20-65 years), including 25 systemically healthy patients with chronic periodontitis (group 1) and 25 diabetic patients with chronic periodontitis (group 2) were enrolled. In each patient, test and control sites were identified for the placement of green tea and placebo strips, respectively. Gingival Index (GI), Probing Pocket Depth (PPD), and Clinical Attachment Level (CAL) were examined at baseline, first, second, third, and fourth weeks. Microbiological analysis for Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans was performed at baseline and fourth week.

Results:

The in vitro study showed 10.67% green tea release at 30 min; thereafter, a slow release was noted till 120 min.

In vivo study:

Both groups showed significant reduction in GI scores at the test sites. Group 1 showed significant (P < 0.001) PPD reduction at different time intervals at the test sites. However, group 2 showed significant reduction from baseline (5.30 ± 0.70) to fourth week (3.5 ± 0.97). Statistically significant gain in CAL at the test sites was observed both in group 1 (1.33 mm) and group 2 (1.43 mm). The prevalence of P. gingivalis in group 1 test sites was significantly reduced from baseline (75%) to fourth week (25%).

Conclusions:

Local drug delivery using green tea extract could be used as an adjunct in the treatment of chronic periodontitis in diabetic and non-diabetic individuals.

Molecular mechanisms involved in the bidirectional relationship between diabetes mellitus and periodontal disease

Both diabetes and periodontitis are chronic diseases. Diabetes has many adverse effects on the periodontium, and conversely periodontitis may have deleterious effects further aggravating the condition in diabetics. The potential common pathophysiologic pathways include those associated with inflammation, altered host responses, altered tissue homeostasis, and insulin resistance. This review examines the relationship that exists between periodontal diseases and diabetes mellitus with a focus on potential common pathophysiologic mechanisms.

Investigation of the effect of type 2 diabetes mellitus on subgingival plaque microbiota by high-throughput 16S rDNA pyrosequencing

Diabetes mellitus is a major risk factor for chronic periodontitis. We investigated the effects of type 2 diabetes on the subgingival plaque bacterial composition by applying culture-independent 16S rDNA sequencing to periodontal bacteria isolated from four groups of volunteers: non-diabetic subjects without periodontitis, non-diabetic subjects with periodontitis, type 2 diabetic patients without periodontitis, and type 2 diabetic patients with periodontitis. A total of 71,373 high-quality sequences were produced from the V1-V3 region of 16S rDNA genes by 454 pyrosequencing. Those 16S rDNA sequences were classified into 16 phyla, 27 classes, 48 orders, 85 families, 126 genera, and 1141 species-level OTUs. Comparing periodontally healthy samples with periodontitis samples identified 20 health-associated and 15 periodontitis-associated OTUs. In the subjects with healthy periodontium, the abundances of three genera (Prevotella, Pseudomonas, and Tannerella) and nine OTUs were significantly different between diabetic patients and their non-diabetic counterparts. In the subjects carrying periodontitis, the abundances of three phyla (Actinobacteria, Proteobacteria, and Bacteriodetes), two genera (Actinomyces and Aggregatibacter), and six OTUs were also significantly different between diabetics and non-diabetics. Our results show that type 2 diabetes mellitus could alter the bacterial composition in the subgingival plaque.

Clinical review: Association between metabolic syndrome and periodontitis: a systematic review and meta-analysis

BACKGROUND

Several epidemiological studies have reported an association between metabolic syndrome (MetS) and periodontal diseases (PDs). The aim of this systematic review was to investigate the existence and magnitude of this association.

MATERIALS AND METHODS

A systematic search of the literature was conducted looking for case-control, cross-sectional, cohort studies and population surveys including patients with measures of MetS and PD. Ovid MEDLINE, EMBASE, LILACS, and Cochrane library databases were used for the search by 2 independent reviewers. A meta-analysis was conducted to investigate the association for coexistence of MetS and PD.

RESULTS

A total of 20 studies were included in the review, from an initial search of 3486 titles. Only 1 study reported longitudinal data on the onset of MetS components in association with periodontal measures. However, several studies investigated coexistence. A random effects meta-analysis showed that the presence of MetS is associated with the presence of periodontitis in a total of 36 337 subjects (odds ratio = 1.71; 95% confidence interval = 1.42 to 2.03). When only studies with "secure" diagnoses were included (n = 16 405), the magnitude of association increased (odds ratio = 2.09; 95% confidence interval = 1.28 to 3.44). Moderate heterogeneity was detected (I(2) = 53.6%; P = .004).

CONCLUSIONS

This review presents clear evidence for an association between MetS and periodontitis. The direction of the association and factors influencing it should be investigated by longitudinal and treatment studies. Periodontal diagnostic procedures should be routinely carried out in MetS patients.

Effects of vitamin E on pathological changes induced by diabetes in rat lungs

Twenty-fourmale rats were divided into three groups: Control (C), non-treated diabetic (NTD), and vitamin E-treated diabetic (VETD) groups. After 6 weeks, we evaluated the changes in the alveolar epithelium, alveolar septum thickness, Hcy, and cathepsin G levels in the lung tissue and plasma serine protease inhibitor levels.The results revealed a significant increase in alveolar septum thickness, a high number of type II pneumocytes, high number of glycogen granules, increased vascular elastic membrane thickness, and increased Hcy and cathepsin G levels in the diabetic rats. Plasma level of serine protease inhibitors showed a significant decrease in the NTD animals. The vitamin E-treated rats showed significant amelioration of lung tissue changes, as well as restoration of high cathepsin G, Hcy levels, and serine protease inhibitors when compared to the control rats. These results suggest that diabetes induces lung tissue changes that may be stimulated by Hcy and cathepsin G mediated oxidative stress by, and protective effect could be achieved by using vitamin E.

Periodontal inflammatory conditions among gutka chewers and non-chewers with and without prediabetes

BACKGROUND

It is known that gutka chewing jeopardizes periodontal health; however, severity of periodontal inflammation in gutka chewers with and without prediabetes remains unknown. The aim of this study is to investigate the association of periodontal inflammatory conditions with gutka chewing and prediabetes.

METHODS

In this cross-sectional study, the effect of gutka use on periodontal health is investigated among 44 individuals with prediabetes and 44 without prediabetes. Demographic information regarding age, sex, duration of prediabetes, and gutka-chewing habits was collected using a questionnaire. Periodontal inflammatory conditions (plaque index [PI], bleeding on probing [BOP], probing depth [PD], marginal bone loss [MBL]) and fasting blood glucose levels (FBGLs) were recorded. Group differences in periodontal inflammatory parameters were tested using univariate and multivariable analyses (α ≤5%).

RESULTS

Periodontal inflammatory parameters (PI, BOP, and PD) were significantly higher in individuals with prediabetes irrespective of gutka-chewing habit (P <0.05). Odds of periodontal inflammation in individuals with prediabetes were nine times higher than in healthy controls (95% confidence interval [CI] = 3.4 to 23.6). Gutka chewing alone, chewing among individuals with prediabetes, and chewing among healthy controls did not significantly increase the odds of periodontal inflammatory conditions. Individuals with prediabetes were significantly more likely to have periodontal inflammation than individuals without prediabetes even after controlling for sex and gutka chewing (odds ratio = 13.2; 95% CI = 4.3 to 40.7).

CONCLUSION

In medically healthy individuals, periodontal inflammatory conditions are worse in gutka chewers compared to non-chewers; in patients with prediabetes, the severity of periodontal inflammation is governed by hyperglycemia when compared to habitual gutka usage.

Lung alterations in a rat model of diabetes mellitus: effects of antioxidant therapy

OBJECTIVE

To evaluate structural alterations of the lung in rats with diabetes mellitus (DM), by quantifying oxidative stress and DNA damage, as well as to determine the effects that exogenous superoxide dismutase (SOD) has on such alterations.

METHODS

A controlled experimental study involving 40 male Wistar rats, divided into four groups (10 animals each): control; SOD-only (without DM but treated with SOD); IDM-only (with streptozotocininduced DM but untreated); and IDM+SOD (with streptozotocin-induced DM, treated with SOD). The animals were evaluated over a 60-day period, day 0 being defined as the day on which the streptozotocin-injected animals presented glycemia > 250 mg/dL. The SOD was administered for the last 7 days of that period. At the end of the study period, samples of lung tissue were collected for histopathological analysis, evaluation of tissue oxidative stress, and assessment of DNA damage.

RESULTS

There were no significant differences among the groups regarding DNA damage. In the IDM-only group, there was a significant increase in the extracellular matrix and significantly greater hyperplasia of the capillary endothelium than in the SOD-only and control groups. In addition, there were significant changes in type II pneumocytes and macrophages, suggesting an inflammatory process, in the IDM-only group. However, in the IDM+SOD group, there was a reduction in the extracellular matrix, as well as normalization of the capillary endothelium and of the type II pneumocytes.

CONCLUSIONS

Exogenous SOD can reverse changes in the lungs of animals with induced DM.

The expression of antioxidant enzymes in the gingivae of type 2 diabetics with chronic periodontitis

OBJECTIVES

There is controversial evidence regarding the levels of antioxidant molecules in type 2 diabetes periodontitis patients. Thus, the aim of the present study was to evaluate the gene expression of antioxidant enzymes in the gingival tissue of poorly and well-controlled type 2 diabetic subjects with chronic periodontitis (CP).

DESIGN

Gingival biopsies were harvested from systemically and periodontally healthy subjects (n=12), systemically healthy subjects with CP (n=15), well-controlled (n=8) and poorly controlled (n=14) diabetic subjects with CP. The messenger RNA (mRNA) levels of peroxiredoxin (PRDX) 1 and 2, catalase (CAT), glutathione peroxidase (GPX1) and superoxide dismutase (SOD) 1 and 2 were measured by quantitative polymerase chain reaction (qPCR).

RESULTS

The results showed that PRDX1 and GPX1 were up-regulated by periodontitis (p<0.05), independently of the glycaemic status, whilst PRDX2 and SOD2 genes were slightly influenced by periodontitis, but significantly induced when periodontitis was associated with DM, especially under a poor glycaemic control (p<0.05). Moreover, CAT and SOD1 expressions were not significantly influenced by any of these inflammatory disorders (p>0.05).

CONCLUSION

In conclusion, both PRDX1 and GPX1 were overexpressed in CP whilst PRDX2 and SOD2 were up-regulated especially in the poorly controlled diabetic group with CP.

Periodontitis and risk of diabetes mellitus

Diabetes mellitus (DM) is a complex disease with varying degrees of systemic and oral complications. The periodontium is also a target for diabetic damage. Diabetes is a pandemic in both developed and developing countries. In recent years, a link between periodontitis and diabetes mellitus has been postulated. The oral cavity serves as a continuous source of infectious agents that could further worsen the diabetic status of the patient and serve as an important risk factor deterioration of diabetes mellitus. The present review highlights the relationship between diabetes mellitus and periodontitis. The potential mechanisms involved in the deterioration of diabetic status and periodontal disease are also discussed.

The influence of diabetes mellitus on periodontal tissues: a pilot study

Purpose

The purpose of this study was to preliminarily evaluate the influence of diabetes mellitus (DM) on periodontal tissue without establishment of periodontitis.

Methods

Seven-week-old db/db mice were used for the diabetic experimental group and systematically healthy mice of the same age were used as controls. After 1 week of acclimatization, the animals were sacrificed for hard and soft tissue evaluation. The pattern of bone destruction was evaluated by stereomicroscope evaluation with alizarin red staining and radiographic evaluation by microscopic computerized tomography images. Histological evaluation was performed with hematoxylin and eosin stain for evaluation of soft tissue changes.

Results

In both stereomicroscope evaluation and radiograph image analysis, aggressive form of bone destruction was observed in diabetic animals when compared to the systematically healthy controls. In histological evaluation, apical migration of junctional epithelium with slight inflammatory cell infiltration was observed with disarrangement of connective tissue fibers.

Conclusions

Within the limits of this study, diabetic animals presented distortion in periodontal attachment and an aggressive bone loss pattern when compared to the healthy controls, suggesting that DM has an independent effect on periodontal tissue destruction irrespective of the presence or absence of periodontal disease.

Preventive effects of a cocoa-enriched diet on gingival oxidative stress in experimental periodontitis

BACKGROUND

Oxidative stress affects the progression of periodontitis. Cocoa is a rich source of flavonoids with antioxidant properties, which could suppress gingival oxidative stress in periodontal lesions. The purpose of the present study was to investigate the effects of a cocoa-enriched diet on gingival oxidative stress in a rat-periodontitis model.

METHODS

In this 4-week study, rats were divided into three groups (n = 8/group): a control group (fed a regular diet) and two periodontitis groups (fed a regular diet or cocoa-enriched diet [10% of food intake]). Periodontitis was induced by ligature placement around the mandibular first molars. Serum levels for reactive oxygen metabolites were measured at baseline and 2 and 4 weeks. At 4 weeks, the levels of 8-hydroxydeoxyguanosine and reduced/oxidized glutathione ratio were determined to evaluate gingival oxidative damage and antioxidant status, respectively.

RESULTS

Rats with experimental periodontitis that were fed a regular diet showed an increase in the level of serum reactive oxygen metabolites in a time-dependent manner. These rats also had an increased 8-hydroxydeoxyguanosine level and decreased reduced/oxidized glutathione ratio in the gingival tissue, inducing alveolar bone loss and polymorphonuclear leukocyte infiltration. Although experimental periodontitis was induced in the rats fed a cocoa-enriched diet, they did not show impairments in serum reactive oxygen metabolite level and gingival levels for 8-hydroxydeoxyguanosine and reduced/oxidized glutathione ratio. Alveolar bone loss and polymorphonuclear leukocyte infiltration after ligature placement were also inhibited by cocoa intake.

CONCLUSION

Consuming a cocoa-enriched diet could diminish periodontitis-induced oxidative stress, which, in turn, might suppress the progression of periodontitis.