Obesity and oxidative stress in patients with different periodontal status: a case-control study

Mitochondrial Dysfunction in Periodontitis and Associated Systemic Diseases: Implications for Pathomechanisms and Therapeutic Strategies

Periodontitis is a chronic infectious disorder damaging periodontal tissues, including the gingiva, periodontal ligament, cementum, and alveolar bone. It arises from the complex interplay between pathogenic oral bacteria and host immune response. Contrary to the previous view of "energy factories", mitochondria have recently been recognized as semi-autonomous organelles that fine-tune cell survival, death, metabolism, and other functions. Under physiological conditions, periodontal tissue cells participate in dynamic processes, including differentiation, mineralization, and regeneration. These fundamental activities depend on properly functioning mitochondria, which play a crucial role through bioenergetics, dynamics, mitophagy, and quality control. However, during the initiation and progression of periodontitis, mitochondrial quality control is compromised due to a range of challenges, such as bacterial-host interactions, inflammation, and oxidative stress. Currently, mounting evidence suggests that mitochondria dysfunction serves as a common pathological mechanism linking periodontitis with systemic conditions like type II diabetes, obesity, and cardiovascular diseases. Therefore, targeting mitochondria to intervene in periodontitis and multiple associated systemic diseases holds great therapeutic potential. This review provides advanced insights into the interplay between mitochondria, periodontitis, and associated systemic diseases. Moreover, we emphasize the significance of diverse therapeutic modulators and signaling pathways that regulate mitochondrial function in periodontal and systemic cells.

Meta-Analysis of Assessment of Total Oxidative Stress and Total Antioxidant Capacity in Patients with Periodontitis

Background

Periodontitis is intricately linked to oxidative stress-antioxidant (redox) imbalance. The antioxidant system scavenges the oxygen free radicals in biological fluids in patients with periodontitis. However, little is still known about the free radicals mediated oxidative stress and reductive ability of the antioxidant system. Thus, the present meta-analysis aims to quantitatively review the literature that assessed the oxidative stress marker total oxidative stress (TOS) and total antioxidant capacity (TAC) in various biological fluids of patients with periodontitis. Methodology. Electronic databases were searched for studies that assessed TOS and TAC levels in various biological samples of patients with periodontitis.

Results

From the 1,812 articles identified, 1,754 were excluded based on title and abstract screening due to irrelevance to the topic of interest. A full-text assessment of the remaining 58 articles led to the selection of 42 articles that satisfied the inclusion criteria. Of these, only 24 studies had consistent data for quantitative analysis. The periodontitis group displayed significantly elevated TOS levels (p < 0.05) in serum, gingival crevicular fluid (GCF), and saliva samples in the studies evaluated. In contrast, the periodontitis group exhibited significantly attenuated TAC levels (p < 0.01) compared to healthy controls in plasma, serum, and GCF samples of the studies evaluated, which was insignificant in salivary samples (p=0.433). At the same time, the periodontitis group displayed insignificantly elevated TAC levels after periodontal therapy (p=0.130).

Conclusions

The present meta-analysis showed significantly higher TOS and lower TAC in periodontitis, reflecting the elevated oxidative stress level than the control group. Clinical Relevance. Scientific rationale for the study: The imbalance between oxidants and antioxidants (oxidative stress (OS)) plays a critical role in the onset and progression of periodontitis; the assessment of the relationship between OS-related biomarkers in regional samples and systemic samples of patients with periodontitis helps us to evaluate the periodontal disease progression. The OS biomarker levels can be used to assess periodontal disease and therapeutic efficacy.

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.

Assessment of Oxidative Stress by the Estimation of Lipid Peroxidation Marker Malondialdehyde (MDA) in Patients with Chronic Periodontitis: A Systematic Review and Meta-Analysis

Objective

The present systematic review and meta-analysis aimed to assess the oxidative stress-mediated lipid peroxidation end product malondialdehyde (MDA) in periodontitis using the available literature.

Materials and Methods

An electronic literature search was performed for the published articles from 2000 to 2022 in PubMed (MeSH), Science Direct, Wiley Online library, and cross-reference using specific keywords.

Results

The literature search identified 1,166 articles. After analyzing the abstracts of the obtained articles, the articles were excluded for the following reasons: duplicate studies (n = 395) and not relevant to the research question (n = 726). The remaining 45 articles were chosen for full-text evaluation. Finally, the present qualitative synthesis selected 34 articles that met the inclusion criteria for evaluation and removed the articles which did not meet the required criteria (n = 11). Out of these, 16 articles had coherent data for quantitative synthesis. The meta-analysis used the standardized mean differences method at a 95% confidence interval by random-effects model. The periodontitis group displayed significantly higher MDA levels (P < 0.001) in gingival crevicular fluid, saliva, and serum samples of the studies analyzed than the healthy control.

Conclusion

The analyzed studies showed significantly higher MDA levels in various biological samples of patients with periodontitis, supporting the role of elevated oxidative stress and consequent lipid peroxidation in periodontitis.

Obesity as a modifying factor of periodontal therapy outcomes: local and systemic adipocytokines and oxidative stress markers

OBJECTIVES

Adipocytokines and oxidative stress (OS) are involved in the pathogenesis of both obesity and periodontitis. The aim of this study was to evaluate periodontal therapy outcomes in terms of serum and gingival crevicular fluid (GCF) levels of adipocytokines and OS markers in obese patients with periodontitis, in order to have an insight into the association between obesity and periodontitis.

MATERIALS AND METHODS

A total of 39 patients (20 obese, 19 non-obese) with periodontitis were included in this study. Clinical periodontal parameters were assessed; serum and GCF levels of adipocytokines and OS markers were evaluated by ELISA at baseline and 3 months after non-surgical periodontal therapy.

RESULTS

Significant improvements in clinical periodontal parameters were observed in both groups at 3 months (p < 0.01). While serum levels of TNF-α, leptin, and total oxidant status (TOS) in the obese group were higher at baseline (p < 0.01), leptin levels remained higher at 3 months despite a significant decrease (p < 0.01). Although NSPT improved GCF levels of total antioxidant status (TAS) and TOS in both groups, they were significantly different between the groups after therapy (p < 0.05).

CONCLUSIONS

It seems that leptin, TNF-α, and TOS contribute to systemic inflammatory and oxidative state in patients with obesity. Despite improvements in clinical periodontal parameters, obesity might be a modulating factor in the development and progression of periodontal disease in terms of some adipocytokines and OS markers.

CLINICAL RELEVANCE

Since the global burden of both obesity and periodontitis is continuously increasing, the management of these inflammatory diseases has become more important. The current study contributes to our understanding of the role of OS and adipocytokines on the relationship between obesity and periodontitis by response to periodontal treatment.

The effect of the composition of Soderm®-Forte gel and the new injectable form of Rexod® on pathology findings in gingival tissue in experimental periodontitis in rats

Introduction: Periodontitis is the most important problem of modern dentistry. The development of new medicines and treatment regimens for patients with periodontal complex lesions is a strategic direction of modern pharmacology and dentistry. In this view, pride of place goes to morphological research, which allows not only to study the effect of drugs on pathomorphological changes in periodontal tissues, but also to estimate their therapeutic effectiveness. Aim of the study: to determine the nature of the effect of the composition of Soderm®-Forte gel and the new injectable form of Rexod® on the pathology findings in gingival tissue of rats with experimental periodontitis.

Materials and methods: Experimental periodontitis (EP) was induced in rats by ligature method. The study was performed according to the following algorithm: animals with intact periodontium; animals with untreated EP; animals with EP treated with traditional drug therapy (TDT); animals with EP treated with combinations of TDT with Soderm®-Forte gel and TDT with Soderm®-Forte gel and the new injectable form (NIF) of Rexod®. For pathomorphological examination, biopsy specimen was taken from the gingival margin of the lower incisors. The ImageJ software was used for computer morphometry.

Results and discussion: Examination of the gum samples revealed moderate therapeutic effects of the TDT. The combinations of TDT with Soderm®-Forte gel and, to a greater extent, TDT with Soderm®-Forte gel and the NIF of Rexod® showed high pharmacotherapeutic efficacy, manifested in rapid regeneration of the gingival tissues.

Conclusion: The combination of TDT, Soderm®-Forte gel and the NIF of Rexod® shows the most beneficial effect on the pathological processes in the gum. The pharmacotherapeutic effect of the studied combination promotes the earliest regeneration of damaged gum tissues and reduces the risk of persistent pathology changes in them.

Sodium butyrate protects against oxidative stress in high-fat-diet-induced obese rats by promoting GSK-3β/Nrf2 signaling pathway and mitochondrial function

Sodium butyrate (NaB), obtained by fermenting dietary fiber via intestinal microflora, was recently shown to improve the activity of some antioxidant enzymes in vivo. This study aims to investigate the term changes of mitochondrial energy metabolism and redox homeostasis in skeletal muscles and clarify the regulatory mechanism and dose effect of NaB on skeletal muscle. Male Sprague-Dawley rats were divided into the control group, obesity-prone (OP) group and obesity-resistant (OR) group based on the gain of body weight after 8 weeks' of feeding high-fat diet (HFD), followed by sacrificing rats at the end of 20th week. NaB intervention (12 weeks) could effectively reduce the body weight of rats in the OP and OR groups. NaB also mediated upregulation of antioxidant enzyme activity and GSH/GSSG ratio, while reducing reactive oxygen species (ROS) levels and malondialdehyde (MDA) content. At the molecular level, NaB upregulated Pi3k, Nrf2, Nqo-1, and Ho-1, but downregulated Gsk-3β mRNA expression by regulating the Nrf2 antioxidant pathway to enhance tissue antioxidant capacity. At the same time, NaB intervention significantly upregulated Glut4, Irs-1, Pdx1, and MafA, expression in gastrocnemius muscles of OP and OR rats, and elevated insulin secretion and muscle insulin sensitivity. Thus, NaB activates antioxidant pathway, improves the antioxidant capacity of obese rat tissues and promotes glucose metabolism. PRACTICAL APPLICATIONS: This study found that obesity-prone and obesity-resistant rats have differences in mitochondrial redox homeostasis and energy metabolism in tissues. Meanwhile, sodium butyrate can effectively promote muscle protein synthesis, increase insulin sensitivity, and promote glucose metabolism in obesity rats. Thus, sodium butyrate supplementation or increasing intestinal butyrate production (e.g., by consuming foods rich in dietary fiber) is a potential means of improving the body's glucose metabolism and obesity profile.

Mendelian randomization highlights the causal association of obesity with periodontal diseases

AIM

The underlying mechanisms connecting obesity and periodontal diseases remain unclear. This study investigates the potential causal association of obesity with periodontal diseases using Mendelian randomization (MR).

MATERIALS AND METHODS

Single-nucleotide polymorphisms of obesity traits including body mass index (BMI), waist circumference (WC), and WC adjusted for BMI (WCadjBMI) from large-scale genome-wide association studies were screened for instrumental variables. The single trait periodontitis and the combined trait comprising periodontitis and loose teeth were adopted as surrogates for periodontal diseases. Inverse-variance weighted (IVW), series of sensitivity analyses and multivariable MR were employed to determine the association of obesity with periodontal diseases.

RESULTS

IVW results showed that per 1-SD increment in BMI (odds ratio, OR = 1.115; 95% confidence interval [CI] = 1.064-1.169; p < .001) and WC (OR = 1.117; 95% CI = 1.052-1.185; p < .001), but not WCadjBMI, were significantly associated with an increased risk of periodontitis/loose teeth. Moreover, the MR estimates were consistent across other MR sensitivity analyses and multivariable MR. However, a causal association of obesity with the single trait periodontitis was not identified.

CONCLUSIONS

The presented evidence supports previous epidemiological findings by showing a potential causal association of genetic liability to obesity with periodontal diseases. The biological mechanisms underlying this association warrant further investigation.

Obesity, Bone Loss, and Periodontitis: The Interlink

Obesity and periodontitis are both common health concerns that have given rise to considerable economic and societal burden worldwide. There are established negative relationships between bone metabolism and obesity, obesity and diabetes mellitus (DM), and DM and periodontitis, to name a few, with osteoporosis being considered a long-term complication of obesity. In the oral cavity, bone metabolic disorders primarily display as increased risks for periodontitis and alveolar bone loss. Obesity-driven alveolar bone loss and mandibular osteoporosis have been observed in animal models without inoculation of periodontopathogens. Clinical reports have also indicated a possible association between obesity and periodontitis. This review systematically summarizes the clinical periodontium changes, including alveolar bone loss in obese individuals. Relevant laboratory-based reports focusing on biological interlinks in obesity-associated bone remodeling via processes like hyperinflammation, immune dysregulation, and microbial dysbiosis, were reviewed. We also discuss the potential mechanism underlying obesity-enhanced alveolar bone loss from both the systemic and periodontal perspectives, focusing on delineating the practical considerations for managing periodontal disease in obese patients.

Assessment of peri-implant parameters clinical and radiographic in obese and non-obese along with destructive pro-inflammatory cytokines IL-1β - and IL-6 treated with Photodynamic therapy

AIM

The present study aims to compare and evaluate radiographic and clinical parameters along with salivary proinflammatory cytokine profiles (IL-1β - and IL-6) in obese with peri-implantitis.

MATERIAL AND METHODS

Obese and non-obese participants in the present study were 80. The nonobese and obese participants were scrutinized based on inclusion and exclusion criteria. All participants both obese and non-obese were subjected to full mouth mechanical debridement (MD). A single session of Photodynamic therapy (PDT) was provided to all obese participants. Clinical peri-implant parameters peri-implant plaque index (PIPI), Peri-implant bleeding on probing (PIBoP), peri-implant probing depth (PIPD) were assessed at baseline, three months, and six months. Marginal bone loss (MBL) was also assessed. Enzyme-linked immunosorbent assay (ELISA) was used to check the levels of IL-1β - and IL-6 in unstimulated whole saliva samples. All the parameters were assessed using the Kruskal Wallis test and analysis of variance (ANOVA). Overall characteristics were assessed using descriptive statistics. SPSS software was used for statistical analysis.

RESULTS

Clinical baseline periodontal parameters PIPI, PIBoP, PIPD, and MBL in non-obese participants were significantly lower compared to group I obese participants at baseline (p < 0.05). At 3 months follow-up PDT adjunct to MD in group 1 obese participants PIPI and PIPD were significantly lower compared to MD alone in non-obese participants PIP1 and PIPD. At 6 months follow up, non-obese participants with peri-implantitis treated with MD demonstrated PIPI and PIPD significantly lower compared to obese participants treated with PDT adjunct to MD CONCLUSION: : PDT adjunctive to MD enhanced periodontal parameters i.e., peri-implant probing depth, peri-implant plaque index, and peri-implant bleeding on probing in obese with peri-implantitis. Moreover, obese individuals with peri-implantitis demonstrated high levels of proinflammatory cytokines IL-1β and IL-6 than control.

Influence of adjunctive non-surgical peri‑implant therapy on clinical and salivary cytokine profile in obese patients

AIM

The present study aimed to evaluate the impact of Photodynamic therapy (PDT) and Er,Cr:YSGG laser (ECL) adjunct to nonsurgical mechanical debridement (NSMD) in comparison to conventional NSMD in overweight individuals with peri‑implant disease on peri‑implant inflammatory parameters and cytokine levels of IL-6 and TNF-α in Peri-implant crevicular fluid (PICF) MATERIALS AND METHODS: Recruitment of volunteers was performed from the outpatient department according to predefined inclusion and exclusion criteria. Group 1 consisted of obese participants who underwent peri‑implant mechanical debridement (MD); group 2, obese participants who experienced MD adjunct to ECL, and in group 3, obese participants were treated with MD and adjunct PDT. Clinical periodontal parameters, plaque index (PI), bleeding index (BI) and probing depth (PD) along with crestal bone loss (CBL) were assessed at baseline, 3 months, and 6 months. PICF was collected to evaluate the levels of IL-6 and TNF-α. Kruskal-Wallis and Bonferroni post hoc test were employed for the comparison of peri‑implant inflammatory parameters and PICF cytokine profiles among the study groups.

RESULTS

Clinical peri‑implant parameters (PI, BI and PD) at baseline among subjects in group 1, group 2 and group 3 were comparable (p > 0.05). At 3 months follow up, mean scores of peri‑implant PI, BI, and PD (P <0.05) in group 1 (control) were significantly higher compared to group 2 (ECL) and 3 (PDT) (p < 0.05). At 6 months follow-up, PI and BI mean scores among groups 1, 2, and 3 were comparable (p>0.05). At 6 months participants in groups 2 and 3 noted significant difference (p<0.05) compared to baseline with no difference noted in the control group (p>0.05).

CONCLUSION

Photodynamic therapy and Er, Cr: YSGG adjunct to NSMD demonstrated significant improvement in peri‑implant inflammatory parameters in obese individuals. Multicentric clinical trials are suggested to extrapolate the findings of the present study.

Estimation of serum, salivary, and gingival crevicular uric acid of individuals with and without periodontal disease: A systematic review and meta-analysis

Introduction:

Uric acid (UA) levels in serum, salivary, and gingival crevicular fluid (GCF) may be associated with periodontal diseases. Hence, this study aimed to estimate the UA concentration in serum, saliva, and GCF of periodontal disease and non-periodontal disease subjects by conducting a systematic review and a meta-analysis of the reported studies.

Materials and Methods:

A review of the available literature was searched in the electronic databases of PubMed, Cochrane, Science Direct, and EBSCO for the relevant publications. All the related case–control, cross-sectional, and cohort studies reporting the UA levels in the blood, salivary, and GCF between periodontal disease patients and healthy controls were analyzed. Significant heterogeneity was observed in the studies. Hence, a continuous random-effects model was used. The findings are described in forest plots with the point estimations and 95% confidence interval (CI). A value of P less than 5% was considered as a significant heterogeneity test.

Results:

Of the initial 166 study titles screened, 14 reported papers were eligible for quantitative review. The subgroup analysis of serum UA revealed a mean difference of 0.299 (95% CI: 0.029–0.569, I²=85.64%, P<0.001), indicating an increase in the UA levels in periodontal disease. However, the subgroup analysis by salivary UA demonstrated a mean difference of −0.783 (95% CI: −1.577–0.011, I²= 94.62%, P<0.001), suggesting a lower side of the UA level in periodontal diseases. The subgroup analysis based on case–control studies showed a mean difference of 0.004 (95% CI: −0.286–0.294, I²=84.99%, P<0.001), indicating no changes in UA levels in periodontal disease. On the contrary, cohort studies and cross-sectional studies showed a mean difference : 95% CI: −1.016, −3.272–1.241, I²=97.84%, P<0.001 and 95%: −1.230, −4.410–1.949, I²=97.7%, P<0.001, indicating reduction in UA levels in periodontal disease cases.

Conclusion:

The current review suggests an increase in the serum UA levels in periodontal disease than in healthy controls. Contrarily, the salivary UA levels decreased in periodontal disease patients. It is unknown why UA levels are opposite in the blood and saliva of periodontal disease patients requiring further explanation.

Association between clinical measures of gingival inflammation and obesity in adults: systematic review and meta-analyses

OBJECTIVE

This study aimed to systematically review the literature about the association between clinical measures of gingival inflammation and obesity in adults.

MATERIAL AND METHODS

Searches for studies were performed in five databases (Medline-PubMed, Scopus, Web of Science, Cochrane Library, and Embase) to compile studies of any design that evaluated the association between clinical measures of gingival inflammation and obesity in adults. Selection of studies, data extraction and risk of bias analysis were performed independently by two reviewers, and a third researcher was involved to resolve disagreements. Meta-analyses were performed for measures of gingival inflammation as compared to body mass index (BMI). Independent analyses were performed for studies involving periodontitis, gingivitis, and population-based/studies that did not provide a periodontal diagnosis. Standard mean deviation (SMD) and its 95% confidence interval (95%CI) were estimated.

RESULTS

Ninety studies were included (cross-sectional/clinical trials [n=82], case-control [n=3], cohorts [n=5]). Most of the studies demonstrated no significant difference in the measures of gingival inflammation regardless of the comparison performed. However, meta-analysis showed that among individuals with periodontitis, significantly higher levels of gingival inflammation are observed in those with obesity (n of individuals=240) when compared to those who were not obese (n of individuals=574) (SMD:0.26; 95%CI:0.07-0.44). When considering population-based/those studies that did not provide periodontal diagnosis, significantly higher measures of gingival inflammation were observed in the groups with higher BMI.

CONCLUSIONS

Within the limitations of the present study, it was concluded that higher measures of gingival inflammation may be expected for those with higher BMI.

CLINICAL RELEVANCE

Clinicians must be aware that higher measures of gingival inflammation may be expected for individuals with higher BMI. However, there is a necessity for further longitudinal studies regarding the association between obesity and gingival inflammation.

Metabolomics of gingival crevicular fluid to identify biomarkers for periodontitis: A systematic review with meta-analysis

The present systematic review aimed to examine periodontitis-specific biomarkers in the gingival crevicular fluid (GCF) that could have a diagnostic relevance, and to provide a qualitative assessment of the current literature. Metabolites are reliable indicators of pathophysiological statuses, and their quantification in the GCF can provide an outlook of the changes associated with periodontitis and have diagnostic value. Relevant studies identified from PubMed, Embase, Cochrane Library, and Scopus databases were examined to answer the following PECO question: "In systemically healthy individuals, can concentration of specific metabolites in the GCF be used to discriminate subjects with healthy periodontium (H) or gingivitis from patients with periodontitis (P) and which is the diagnostic accuracy?" Quality of included studies was rated using a modified version of the QUADOMICS tool. Meta-analysis was conducted whenever possible. After the screening of 1,554 titles, 15 studies were selected, with sample size ranging from 30 to 93 subjects. Eleven studies performed targeted metabolomics analysis and provided data for 10 metabolites. Among the most consistent markers, malondialdehyde levels were found higher in the P group compared with H group (SMD = 2.86; 95% CI: 1.64, 4.08). Also, a significant increase of 8-hydroxy-deoxyguanosine, 4-hydroxynonenal, and neopterin was detected in periodontally diseased sites, while glutathione showed an inverse trend. When considering data from untargeted metabolomic analysis in four studies, more than 40 metabolites were found significantly discriminant, mainly related to amino acids and lipids degradation pathways. Notably, only one study reported measures of diagnostic accuracy. Several metabolites were differentially expressed in GCF of subjects across different periodontal conditions, having a major potential for investigating periodontal pathophysiology and for site-specific diagnosis. Oxidative stress-related molecules, such as malondialdehyde and 8-hydroxy-deoxyguanosine, were the most consistently associated to periodontitis (PROSPERO CRD42020188482).

Periodontitis is an inflammatory disease of oxidative stress: We should treat it that way

Periodontitis is a highly prevalent disease. As it progresses, it causes serious morbidity in the form of periodontal abscesses and tooth loss and, in the latter stages, pain. It is also now known that periodontitis is strongly associated with several nonoral diseases. Thus, patients with periodontitis are at greater risk for the development and/or exacerbation of diabetes, chronic obstructive pulmonary disease, and cardiovascular diseases, among other conditions. Although it is without question that specific groups of oral bacteria which populate dental plaque play a causative role in the development of periodontitis, it is now thought that once this disease has been triggered, other factors play an equal, and possibly more important, role in its progression, particularly in severe cases or in cases that prove difficult to treat. In this regard, we allude to the host response, specifically the notion that the host, once infected with oral periodontal pathogenic bacteria, will mount a defense response mediated largely through the innate immune system. The most abundant cell type of the innate immune system - polymorphonuclear neutrophils - can, when protecting the host from microbial invasion, mount a response that includes upregulation of proinflammatory cytokines, matrix metalloproteinases, and reactive oxygen species, all of which then contribute to the tissue damage and loss of teeth commonly associated with periodontitis. Of the mechanisms referred to here, we suggest that upregulation of reactive oxygen species might play one of the most important roles in the establishment and progression of periodontitis (as well as in other diseases of inflammation) through the development of oxidative stress. In this overview, we discuss both innate and epigenetic factors (eg, diabetes, smoking) that lead to the development of oxidative stress. This oxidative stress then provides an environment conducive to the destructive processes observed in periodontitis. Therefore, we shall describe some of the fundamental characteristics of oxidative stress and its effects on the periodontium, discuss the diseases and other factors that cause oxidative stress, and, finally, review potentially novel therapeutic approaches for the management (and possibly even the reversal) of periodontitis, which rely on the use of therapies, such as resveratrol and other antioxidants, that provide increased antioxidant activity in the host.

Low-intensity Pulsed Ultrasound regulates alveolar bone homeostasis in experimental Periodontitis by diminishing Oxidative Stress

Periodontitis is a widespread oral disease that results in the loss of alveolar bone. Low-intensity pulsed ultrasound (LIPUS), which is a new therapeutic option, promotes alveolar bone regeneration in periodontal bone injury models. This study investigated the protective effect of LIPUS on oxidative stress in periodontitis and the mechanism underlying this process.

Methods: An experimental periodontitis model was induced by administering a ligature. Immunohistochemistry was performed to detect the expression levels of oxidative stress, osteogenic, and osteoclastogenic markers in vivo. Cell viability and osteogenic differentiation were analyzed using the Cell Counting Kit-8, alkaline phosphatase, and Alizarin Red staining assays. A reactive oxygen species assay kit, lipid peroxidation MDA assay kit, and western blotting were used to determine oxidative stress status in vitro. To verify the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an oxidative regulator, during LIPUS treatment, the siRNA technique and Nrf2^-/- mice were used. The PI3K/Akt inhibitor LY294002 was utilized to identify the effects of the PI3K-Akt/Nrf2 signaling pathway.

Results: Alveolar bone resorption, which was experimentally induced by periodontitis in vivo, was alleviated by LIPUS via activation of Nrf2. Oxidative stress, induced via H₂O₂ treatment in vitro, inhibited cell viability and suppressed osteogenic differentiation. These effects were also alleviated by LIPUS treatment via Nrf2 activation. Nrf2 silencing blocked the antioxidant effect of LIPUS by diminishing heme oxygenase-1 expression. Nrf2^-/- mice were susceptible to ligature-induced periodontitis, and the protective effect of LIPUS on alveolar bone dysfunction was weaker in these mice. Activation of Nrf2 by LIPUS was accompanied by activation of the PI3K/Akt pathway. The oxidative defense function of LIPUS was inhibited by exposure to LY294002 in vitro.

Conclusions: These results demonstrated that LIPUS regulates alveolar bone homeostasis in periodontitis by attenuating oxidative stress via the regulation of PI3K-Akt/Nrf2 signaling. Thus, Nrf2 plays a pivotal role in the protective effect exerted by LIPUS against ligature-induced experimental periodontitis.

Clinical and microbiological evaluation of non-surgical periodontal therapy in obese and non-obese individuals with periodontitis: a 9-month prospective longitudinal study

Objective Obesity is a chronic disease that negatively affects an individual's general and oral health. The present study aimed to compare the clinical and microbiological effects of non-surgical periodontal therapy with the full mouth disinfection (FMD) protocol on obese and non-obese individuals at 9 months post-therapy. Methodology This clinical study was first submitted and approved by the Ethics Committee. Fifty-five obese patients and 39 non-obese patients with periodontitis were evaluated. The full-mouth periodontal clinical parameters, clinical attachment level (CAL), probing depth (PD), gingival index (GI), and plaque index (PI), were monitored at baseline, 3, 6, and 9 months after periodontal treatment with full mouth disinfection (FMD) protocol. The mean count of Tannerella forsythia , Porphyromonas gingivalis , Treponema Denticola , and Aggregatibacter actinomycetemcomitans was determined by quantitative polymerase chain reaction on subgingival biofilm samples. Demographic data were assessed by Chi-square test. For clinical and microbiological parameters, two-factor repeated-measures ANOVA was used. Results In both groups, periodontal therapy using the one-stage full-mouth disinfection protocol significantly improved CAL, PD, GI, and PI (p<0.05). Obese and non-obese patients equally responded to non-surgical periodontal therapy (p>0.05). Microbial count found no major differences (p>0.05) between obese and non-obese individuals who had undergone non-surgical periodontal therapy. Conclusions Obesity did not affect the clinical and microbiological outcomes of non-surgical periodontal therapy.

Ferroptosis as an emerging target in inflammatory diseases

Cell survival or death is one critical issue in inflammatory responses. Ferroptosis, which is characterized by iron-dependent lethal lipid peroxidation, has been found to participate in the development of cancers, degenerative brain diseases and ischemia-reperfusion injuries. Incorporation of polyunsaturated fatty acids (PUFAs) into cellular membranes represents a vulnerability to invasion of microbials and sterile stimuli. In addition, the competition for iron in the battle between microbials and host cells underlies infection development. Although host cells have been equipped with complex antioxidant systems to combat lethal accumulation of lipid peroxidation, emerging evidence suggests several pathogens may target PUFAs in the cell membrane, and manipulate ferroptosis as a way for pathogen propagation. Moreover, ferroptosis takes part in the progression of sterile inflammations, such as cigarette smoke-induced chronic obstructive pulmonary disease, stroke and ischemia-reperfusion injuries. As iron-dependent oxidative stress and lipid peroxidation are common features for ferroptosis and inflammatory diseases, underlying mechanisms linking such pathological conditions will be discussed in this review. Progress in the research of ferroptosis may shed more light on the etiology and treatment of inflammatory diseases.

Oxidative stress-related biomarkers in saliva and gingival crevicular fluid associated with chronic periodontitis: A systematic review and meta-analysis

AIM

Oxidative stress (OS) biomarkers have been detected in saliva and gingival crevicular fluid (GCF) during chronic periodontitis (CP) progression; however, the relationship between OS biomarkers and CP progression remains elusive. The purpose of this meta-analysis is to investigate the relationship between local OS biomarkers and CP.

METHODS

This review was conducted through a systematic search from three databases. Studies on CP participants were included as an experimental group, and studies on periodontally healthy (PH) participants were included as a control. Mean effects were expressed as standardized mean difference with their associated 95% confidence intervals.

RESULTS

From a total of 2,972 articles, 32 articles fulfilled the inclusion criteria. We found a significant decrease of total antioxidant capacity and a significant increase of malondialdehyde (MDA), nitric oxide, total oxidant status (TOS), and 8-hydroxy-deoxyguanosine levels in the saliva of CP patients. Moreover, we also found an elevation of MDA level in GCF of CP group when compared with the PH group. There were no significant differences of salivary and GCF superoxide dismutase levels, salivary glutathione peroxidase level, and GCF TOS level between two groups. However, a high heterogeneity was observed among evaluated studies.

CONCLUSIONS

Despite the limitations of this study, the result of our meta-analysis supported the rationale that there was a direct link between CP and OS-related biomarkers' levels in the local site, indicating the important role of OS in the onset and development of CP.

Oxidative stress in chronic periodontitis patients with type II diabetes mellitus

Objective

Oxidative stress (OS) refers to the disequilibrium between free radicals and antioxidant defense mechanisms and is significantly implicated in the pathogenesis of chronic degenerative and inflammatory diseases such as chronic periodontal disease (CP) and diabetes mellitus (DM). This study aimed to evaluate the total antioxidants capacity (TAOC) and total oxidants status (TOS) in the gingival crevicular fluid (GCF) in CP participants with type II DM.

Materials and Methods

A total of 80 participants were allotted into four groups as follows: Group 1: Generalized CP (GCP) without type II DM (n = 20); Group 2: GCP with type II DM (n = 20); Group 3: Type II DM without CP (n = 20); and Group 4: Systemically and periodontally healthy (PH) (n = 20). Clinical parameters such as plaque index, gingival index, probing pocket depth, and clinical attachment level were recorded. Pooled GCF was collected followed by the estimation of TAOC, TOS, and OS index (OSI) using Erel O Colorimetric analysis.

Results

The clinical parameters recorded showed the statistically significant difference (P < 0.001) between the groups. The mean TAOC value was the highest in PH group. The mean TOS and OSI were higher in Group 1, 2, and 3 participants when compared to the PH participants. All the biochemical parameters evaluated showed a statistically significant difference (P < 0.001) between groups.

Conclusions

The study further validates the use of OSI as a marker for periodontal disease activity and emphasizes the role of OS in the pathogenesis of Type II diabetic patients with the chronic periodontal disease.

Periodontal complications with obesity

The purpose of this paper was to identify and summarize current evidence describing periodontal complications associated with obesity. Electronic searches supplemented with manual searches were carried out to identify relevant systematic reviews. Identification, screening, eligibility, and inclusion of studies were performed independently by two reviewers. A MeaSurement Tool to Assess systematic Reviews (AMSTAR) was used to assess the quality and risk of bias of the included reviews. From 430 titles and abstracts screened, 14 systematic reviews were considered as eligible for inclusion in this meta-review. Eight reviews reported on cross-sectional studies investigating the association of obesity and periodontal diseases, 4 included longitudinal studies, 5 addressed response to periodontal therapy, 5 reported on studies investigating biomarkers, and only 2 were related to pediatric population samples. Systematic review summaries in the various study design domains (cross-sectional, longitudinal and experimental) report that obese individuals are more likely to have periodontal diseases, with more severe periodontal conditions, than nonobese individuals, with cross-sectional evidence congruent with longitudinal studies showing that obesity or weight gain increases the risk of periodontitis onset and progression. Published research on the effect of obesity on responses to periodontal therapy, or systemic or local biomarkers of inflammation, is variable and therefore inconclusive based on the evidence currently available, which suggests that overweight/obesity contributes to periodontal complications independently of other risk factors, such as age, gender, smoking, or ethnicity. This evidence supports the need for risk assessments for individual patients to facilitate personalized approaches in order to prevent and treat periodontal diseases.

Protein carbonyl levels in serum, saliva and gingival crevicular fluid in patients with chronic and aggressive periodontitis

Objective

This study aims at evaluating the degree of protein carbonyl (PC) levels in serum, gingival crevicular fluid (GCF) and saliva in patients who suffer from chronic periodontitis (CP) and generalized aggressive periodontitis (GAP).

Materials and methods

A total of 110 individuals took part in the study. Of this number, 35 were CP patients, 43 GAP patients, and the remaining 32 were healthy controls. Measurements regarding the serum, saliva and GCF PC levels were obtained by high-performance liquid chromatography.

Results

No statistically significant difference was found in serum PC levels between the groups (P > 0.05). In terms of salivary levels, the CP group demonstrated a significantly higher level (P < 0.05) of PC level compared to the GAP group. However, the difference was not found statistically significant when the comparison was drawn with the control group (p > 0.05).

The GCF PC level in the CP group had a significantly higher level of concentration compared to the other groups (P < 0.05), whereas the relevant values in the control group were higher than the values in the GAP group (P < 0.05). GCF PC total values (/30 s) were higher in the CP group than the remaining groups (P < 0.05), whereas the relevant values in the GAP group were higher than the values in the control group (P < 0.05). It could be stated that GCF PC levels were significantly correlated, either positively or negatively, with all clinical periodontal parameters (p < 0.05).

Conclusions

The results obtained suggest that PC levels of serum and salivary in periodontitis, when compared to periodontal health, do not seem to change considerably. However, in the CP group, a statistically significant increase in PC levels of GCF was observed. This finding suggests the salient role of local protein carbonylation in the periodontal area in CP. That the CP group had a higher level of PC level than the GAP group underscores the higher protein oxidation levels in CP patients.

Raspberry anthocyanin consumption prevents diet-induced obesity by alleviating oxidative stress and modulating hepatic lipid metabolism

Evidence indicates that raspberries have beneficial effects on chronic diseases. The objective of this study was to examine the beneficial effects of raspberry anthocyanin (RA) on high fat diet-induced obesity and investigate the underlying molecular mechanism. C57BL/6 mice were administered a low-fat diet, high-fat diet, and high-fat diet supplemented with RA at a dose of 200 mg kg-1 of food for 12 weeks. It was found that RA reduced the body weight gain by 63.7%. Furthermore, RA significantly elevated serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities and fecal butyric acid level, remarkably reduced the serum and hepatic lipid profiles, and markedly down-regulated the expression of the tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and nuclear factor κB (NF-κB) genes. Metabolomics analysis conducted using gas chromatography time-of-flight mass spectrometry (GC-TOF/MS) indicated that RA administration promoted the recovery of metabolites involved in glycerophospholipid metabolism, insulin signaling pathway, and glutathione metabolism in the livers of obese mice. These findings suggest that RA may ameliorate diet-induced obesity by alleviating oxidative stress and modulating lipid metabolism.

The role of menopause on the relationship between metabolic risk factors and periodontal disease via salivary oxidative parameters

BACKGROUND

Periodontal disease is shown to be aggravated by an increase in the count of metabolic risk factors. This study aims to evaluate the effects of metabolic risk factors on periodontal parameters and salivary oxidative stress markers related to menopausal status.

METHODS

One hundred and seventy-six women were categorized according to menopausal status, either premenopause (Pre/M) (n = 86) or postmenopause (Post/M) (n = 90). The count of metabolic risk factors was evaluated. Sociodemographics and systemic status were determined via questionnaire and medical records. After clinical periodontal measurements and saliva collection, myeloperoxidase (MPO), total oxidant status (TOS) and total antioxidant capacity (TAOC) were determined by enzyme-linked immunosorbent assay and automatic colorimetric method. Oxidative stress index (OSI) was also calculated.

RESULTS

The count of metabolic risk factors was higher in the Post/M group than the Pre/M group. Periodontal parameters and TOS levels were elevated by an increase in the count of metabolic risk factors. Multivariate regression analyses revealed that periodontal (clinical attachment level and missed teeth) and oxidative (MPO and OSI) parameters increased and TAOC levels decreased due to menopause. Additionally, positive relationships between periodontal and oxidative parameters were determined.

CONCLUSION

These findings suggest that salivary oxidative stress level may be an indicator of worsened periodontal status related to menopause and the count of metabolic risk factors.

Inflammatory and Oxidative Responses in Pregnancies With Obesity and Periodontal Disease

BACKGROUND

Maternal obesity is related to immunologic and inflammatory systemic modifications that may worsen the pregnancy inflammatory status. Hormonal changes during pregnancy can adversely affect oral biofilms and oral health initiating or worsening periodontal diseases, with enhanced local and systemic oxidative stress and inflammation.

OBJECTIVE

The aim of this study was to examine the relationship between local salivary and systemic parameters of oxidative stress and inflammation in relation to obesity and periodontal diseases.

STUDY DESIGN

Sixty-two women with singleton pregnancies were enrolled. Twenty-seven women were normal weight (NW; 18.5< body mass index [BMI] <25 kg/m²) and 35 obese (BMI ≥30 kg/m²). Seventeen of the obese had gestational diabetes mellitus (GDM). During third trimester, periodontal status was evaluated, saliva (s) was collected to assess total antioxidant capacity (s-TAC) and C-reactive protein (s-CRP) levels, and venous plasma (p) was used to measure CRP levels (p-CRP). Maternal, fetal, and placental data were registered at delivery.

RESULTS

Levels of s-TAC, s-CRP, and p-CRP were significantly higher in obese, particularly in the presence of GDM, compared to NW and related to each other ( P = .000; r > 0.59), to maternal BMI ( P = .000; r > 0.52), and fasting glycemia ( P < .002; r > 0.47). Periodontal disease was more frequent in obese groups (80%) versus NW (52%; P = .04), particularly when GDM was diagnosed ( P = .009). A significant interaction effect between maternal BMI and oral condition was found for s-TAC levels. Obese with periodontitis showed significant increase in local and systemic parameters versus NW.

CONCLUSION

Obesity and periodontal disease could synergistically amplify the inflammatory and oxidative status, resulting in increased local and systemic biomarkers particularly when GDM is diagnosed.

Oxidative Stress and Antioxidants in the Diagnosis and Therapy of Periodontitis

Oxidative stress has been implicated in the pathogenesis of numerous diseases. However, large interventional studies with antioxidants failed to show benefits in the prevention or treatment of cardiovascular diseases, cancer, or diabetes mellitus. Numerous clinical studies have confirmed the association of oxidative stress markers and periodontitis. Technical and biological variability is high for most of the analyzed markers and none of them seems to be optimal for routine clinical use. In a research setting, analysis of a palette of oxidative stress markers is needed to cover lipid peroxidation, protein oxidation, and the antioxidant status. The source of reactive oxygen species and their role in the pathogenesis of periodontitis remains unclear. Interventional experiments indicate that oxidative stress might be more than just a simple consequence of the inflammation. Small studies have confirmed that some antioxidants could have therapeutic value at least as an addition to the standard non-surgical treatment of periodontitis. A clear evidence for the efficiency of antioxidant treatment in large patient cohorts is lacking. Potentially, because lowering of oxidative stress markers might be a secondary effect of anti-inflammatory or antibacterial agents. As the field of research of oxidative stress in periodontitis gains attraction and the number of relevant published papers is increasing a systematic overview of the conducted observational and interventional studies is needed. This review summarizes the currently available literature linking oxidative stress and periodontitis and points toward the potential of adjuvant antioxidant treatment, especially in cases where standard treatment fails to improve the periodontal status.

Diet versus jaw bones: Lessons from experimental models and potential clinical implications

The consumption of different types of diets influences not only body health but the bone remodeling process as well. Nutritional components can directly affect maxillary and mandibular alveolar bone microarchitecture. In this review, we focus on the current knowledge regarding the influence of diets and dietary supplementation on alveolar bone. Accumulating evidence from experimental models suggests that carbohydrate- and fat-rich diets are detrimental for alveolar bone, whereas protective effects are associated with consumption of calcium, ω-3, and bioactive compounds. Little is known about the effects of protein-free and protein-rich diets, boron, vitamin C, vitamin E, zinc, and caffeine on alveolar bone remodeling. Adipokines and direct effects of nutritional components on bone cells are proposed mechanisms linking diet and bone. Results from animal models substantiate the role of nutritional components on alveolar bone. It is a well-built starting point for clinical studies on nutritional monitoring and intervention for patients with alveolar bone disorders, especially those who are treatment refractory.

Copper in Diabetes Mellitus: a Meta-Analysis and Systematic Review of Plasma and Serum Studies

Copper (Cu) is an important trace element involved in oxidative stress, which is associated with the onset and progression of diabetes mellitus (DM). However, clinical studies comparing plasma or serum Cu levels in patients with DM and in healthy individuals report conflicting findings. Therefore, in this meta-analysis, we analyzed the circulating levels of Cu associated with DM (including type 1 diabetes mellitus [T1DM] and type 2 diabetes mellitus [T2DM]). We searched the articles indexed in PubMed, OVID, and Cochrane databases, published through January 2016 and meeting our predefined criteria. Requisite data were extracted, and a random-effect model or a fixed-effect model was used to conduct the meta-analysis. Fifteen eligible studies involving a total of 1079 DM patients and 561 healthy controls were identified. Overall, the DM patients showed higher Cu levels than the healthy controls (plasma Cu mean difference [MD] = 1.69 μmol/L, p < 0.0001; serum Cu MD = 4.06 μmol/L, p = 0.005; plasma and serum Cu MD = 2.67 μmol/L, p = 0.006). Stratification based on the type of diabetes also indicated higher levels of Cu in the plasma and serum of DM patients than in healthy controls, respectively. Stratification of DM patients associated with and without complications also revealed similar results. This meta-analysis suggests that DM patients carried higher levels of Cu than healthy individuals. However, international cohort studies are needed to corroborate our findings.

Preventive Effects of Drinking Hydrogen-Rich Water on Gingival Oxidative Stress and Alveolar Bone Resorption in Rats Fed a High-Fat Diet

Obesity induces gingival oxidative stress, which is involved in the progression of alveolar bone resorption. The antioxidant effect of hydrogen-rich water may attenuate gingival oxidative stress and prevent alveolar bone resorption in cases of obesity. We examined whether hydrogen-rich water could suppress gingival oxidative stress and alveolar bone resorption in obese rats fed a high-fat diet. Male Fischer 344 rats (n = 18) were divided into three groups of six rats each: a control group (fed a regular diet and drinking distilled water) and two experimental groups (fed a high-fat diet and drinking distilled water or hydrogen-rich water). The level of 8-hydroxydeoxyguanosine was determined to evaluate oxidative stress. The bone mineral density of the alveolar bone was analyzed by micro-computerized tomography. Obese rats, induced by a high-fat diet, showed a higher gingival level of 8-hydroxydeoxyguanosine and a lower level of alveolar bone density compared to the control group. Drinking hydrogen-rich water suppressed body weight gain, lowered gingival level of 8-hydroxydeoxyguanosine, and reduced alveolar bone resorption in rats on a high-fat diet. The results indicate that hydrogen-rich water could suppress gingival oxidative stress and alveolar bone resorption by limiting obesity.

Anthocyanins from black wolfberry (Lycium ruthenicum Murr.) prevent inflammation and increase fecal fatty acid in diet-induced obese rats

This study aimed to determine whether black wolfberry (Lycium ruthenicumMurr.) anthocyanin (BWA) consumption can alleviate oxidative stress and reduce inflammation in high-fat diet-induced obese male Sprague-Dawley rats.

Visualization of Oxidative Stress Induced by Experimental Periodontitis in Keap1-Dependent Oxidative Stress Detector-Luciferase Mice

The aim of this study was to investigate whether a Keap1-dependent oxidative stress detector-luciferase (OKD-LUC) mouse model would be useful for the visualization of oxidative stress induced by experimental periodontitis. A ligature was placed around the mandibular first molars for seven days to induce periodontitis. Luciferase activity was measured with an intraperitoneal injection of d-luciferin on days 0, 1, and 7. The luciferase activity in the periodontitis group was significantly greater than that in the control group at seven days. The expressions of heme oxygenase-1 (HO-1) and malondialdehyde in periodontal tissue were significantly higher in the periodontitis group than in the control group. Immunofluorescent analysis confirmed that the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) occurred more frequently in the periodontitis group than in the control group. This study found that under oxidative stress induced by experimental periodontitis, the Nrf2/antioxidant defense pathway was activated and could be visualized from the luciferase activity in the OKD-LUC model. Thus, the OKD-LUC mouse model may be useful for exploring the mechanism underlying the relationship between the Nrf2/antioxidant defense pathway and periodontitis by enabling the visualization of oxidative stress over time.