Obesity, diabetes mellitus, atherosclerosis and chronic periodontitis: a shared pathology via oxidative stress and mitochondrial dysfunction?

In Silico Investigation of Traditional Chinese Medicine for Potential Lead Compounds as SPG7 Inhibitors against Coronary Artery Disease

Coronary artery disease (CAD) is the most common cause of heart attack and the leading cause of mortality in the world. It is associated with mitochondrial dysfunction and increased level of reactive oxygen species production. According to the Ottawa Heart Genomics Study genome-wide association study, a recent research identified that Q688 spastic paraplegia 7 (SPG7) variant is associated with CAD as it bypasses the regulation of tyrosine phosphorylation of AFG3L2 and enhances the processing and maturation of SPG7 protein. This study aims to identify potential compounds isolated from Traditional Chinese Medicines (TCMs) as potential lead compounds for paraplegin (SPG7) inhibitors. For the crystallographic structure of paraplegin, the disordered disposition of key amino acids in the binding site was predicted using the PONDR-Fit protocol before virtual screening. The TCM compounds saussureamine C and 3-(2-carboxyphenyl)-4(3H)-quinazolinone, have potential binding affinities with stable H-bonds and hydrophobic contacts with key residues of paraplegin. A molecular dynamics simulation was performed to validate the stability of the interactions between each candidate and paraplegin under dynamic conditions. Hence, we propose these compounds as potential candidates as lead drug from the compounds isolated from TCM for further study in drug development process with paraplegin protein for coronary artery disease.

Herbs as an antioxidant arsenal for periodontal diseases

Herbal medicines have long been used as a traditional mode of therapy for various ailments in India. They are being used increasingly as dietary supplements to ward off common diseases. Periodontal diseases are highly prevalent and can affect up to 90% of the world population. Gingivitis is the mild form whereas periodontitis results in an irreversible loss of supporting structures of the teeth. Even though periodontal pathogens form a crucial component in the etiopathogenesis of periodontitis, there is a growing body of evidence suggesting oxidative stress playing a pivotal role in the disease initiation and progression. Studies have shown a direct correlation between increased levels of biomarkers for tissue damage induced by reactive oxygen species (ROS) to the severity of periodontal disease. Thus, the focus of attention has revolved back to herbal medicines due to their wide spectrum of biological and medicinal activities, lower costs, and higher safety margin. Internet databases Pubmed and Google Scholar were searched, and the most relevant articles were considered for review. This review briefly describes the various herbs with antioxidant capacity and their potency in the treating periodontal disease.

Glutathione levels in plasma, saliva and gingival crevicular fluid after periodontal therapy in obese and normal weight individuals

BACKGROUND AND OBJECTIVE

The purpose of this study was to investigate the effects of obesity on reduced and oxidized glutathione (GSH and GSSG) levels in the gingival crevicular fluid, plasma and saliva of patients with chronic periodontitis and to evaluate the changes after nonsurgical periodontal therapy.

MATERIAL AND METHODS

The study included 60 patients: 30 patients with chronic periodontitis (15 obese patients and 15 normal weight patients) and 30 healthy control subjects (15 obese patients and 15 normal weight patients). Gingival crevicular fluid, plasma and saliva samples were collected, and clinical periodontal measurements were recorded at baseline and at the first month after periodontal therapy from patients with chronic periodontitis. GSH and GSSG levels were analyzed with spectrophotometry.

RESULTS

The GSH levels in the plasma, saliva and gingival crevicular fluid in obese individuals with chronic periodontitis were lower than in normal weight individuals at baseline (p < 0.01). There was a significant difference in the GSH/GSSG ratio in plasma and gingival crevicular fluid between the obese and normal weight groups at baseline (p < 0.01). The GSH levels in plasma, gingival crevicular fluid and saliva were significantly increased in both chronic periodontitis groups after nonsurgical periodontal therapy (p < 0.01). A significant positive correlation was found between GSH levels in saliva, plasma and gingival crevicular fluid in all groups (p < 0.001).

CONCLUSIONS

The study revealed that obesity in patients with chronic periodontitis is associated with decreased GSH levels and the GSH/GSSG ratio. Moreover, nonsurgical periodontal therapy may be helpful for improvement in glutathione values in obese and normal weight individuals with chronic periodontitis.

Quercetin Isolated from Toona sinensis Leaves Attenuates Hyperglycemia and Protects Hepatocytes in High-Carbohydrate/High-Fat Diet and Alloxan Induced Experimental Diabetic Mice

The development of diabetes mellitus is related to oxidant stress induced by a high carbohydrate/high-fat diet (HFD). Quercetin, as a major bioactive component in Toona sinensis leaves (QTL), is a natural antioxidant. However, the exact mechanism by which QTL ameliorate diabetes mellitus is still unknown. In this study, we investigated the hypoglycemic effects and hepatocytes protection of QTL on HFD and alloxan induced diabetic mice. Intragastric administration of QTL significantly reduced body weight gain, serum glucose, insulin, total cholesterol, triglyceride, low density lipoprotein-cholesterol, alanine aminotransferase, and aspartate aminotransferase serum levels compared to those of diabetic mice. Furthermore, it significantly attenuated oxidative stress, as determined by lipid peroxidation, nitric oxide content, and inducible nitric oxide synthase activity and as a result attenuated liver injury. QTL also significantly suppressed the diabetes-induced activation of the p65/NF-κB and ERK1/2/MAPK pathways, as well as caspase-9 and caspase-3 levels in liver tissues of diabetic mice. Finally, micrograph analysis of liver samples showed decreased cellular organelle injury in hepatocytes of QTL treated mice. Taken together, QTL can be viewed as a promising dietary agent that can be used to reduce the risk of diabetes mellitus and its secondary complications by ameliorating oxidative stress in the liver.

Genome-wide transcriptome induced by Porphyromonas gingivalis LPS supports the notion of host-derived periodontal destruction and its association with systemic diseases

Chronic periodontitis (CP) is a prevalent pathogen-associated inflammatory disorder characterized by the destruction of tooth-supporting tissues, and linked to several systemic diseases. Both the periodontopathogen Porphyromonas gingivalis (Pg), and the genetically determined host immune response, are hypothesized to play a crucial role in this association. To identify new target genes for CP and its associated systemic diseases, we investigated the transcriptome induced by Pg in human monocytes using a genome-wide approach. Monocytes were isolated from healthy male volunteers of European origin and challenged with the Pg virulence factor LPS. Array-based gene expression analysis comprising >47,000 transcripts was performed followed by pathway analyses. Transcriptional data were validated by protein and cell surface markers. LPS Pg challenge led to the significant induction of 902 transcripts. Besides known periodontitis-associated targets, several new candidates were identified (CCL23↑, INDO↑, GBP 1/4↑, CFB↑, ISG20↑, MIR155HG↑, DHRS9↓). Moreover, various transcripts correspond to the host immune response, and have been linked to cancer, atherosclerosis and arthritis, thus highlighting the systemic impact of CP. Protein data of immunological markers validated our results. The present findings expand understanding of Pg elicited immune responses, and indicate new target genes and pathways of relevance to diagnostic and therapeutic strategies.

The effect of initial periodontal treatment on plasma, gingival crevicular fluid and salivary levels of 8-hydroxy-deoxyguanosine in obesity

OBJECTIVE

Recent studies have shown adverse effects on the periodontium from the increased production of reactive oxygen species (ROS) in obesity. The purpose of this study was to investigate the effects of obesity on 8-hydroxy-deoxyguanosine (8-OHdG) levels in the bodily fluids of patients with and without periodontal disease and to evaluate changes after initial periodontal treatment.

DESIGN

Forty-five obese individuals and 45 normal-weight individuals were included in this study. Obese and normal-weight groups were classified into three sub-groups: chronic periodontitis (CP), gingivitis (G) and periodontally healthy controls (CTRL). Gingival crevicular fluid (GCF), plasma, saliva samples and clinical measurements were obtained at baseline and a month after initial periodontal treatment. Levels of 8-OHdG were analysed by ELISA.

RESULTS

While plasma 8-OHdG levels were significantly higher at baseline in the obese patients with periodontal disease than in the normal-weight individuals (P<0.05), no significant differences in GCF and saliva 8-OHdG levels were found (P ˃ 0.05). GCF and salivary 8-OHdG levels in obese patients with G and CP were significantly higher than in CTRL groups at baseline (P<0.05). After treatment, 8-OHdG levels were decreased in all groups with periodontal disease (P<0.01). Statistically significant positive correlations were observed between GCF 8-OHdG levels and GI in all the groups (P<0.001).

CONCLUSIONS

The significant increase of plasma 8-OHdG levels in obese patients did not correlate with saliva and GCF 8-OHdG levels when compared to normal-weight individuals. Periodontal treatment had a positive effect on the periodontal parameters and 8-OHdG levels of both obese and normal-weight individuals.

Periodontal Disease-Induced Atherosclerosis and Oxidative Stress

Periodontal disease is a highly prevalent disorder affecting up to 80% of the global population. Recent epidemiological studies have shown an association between periodontal disease and cardiovascular disease, as oxidative stress plays an important role in chronic inflammatory diseases such as periodontal disease and cardiovascular disease. In this review, we focus on the mechanisms by which periodontopathic bacteria cause chronic inflammation through the enhancement of oxidative stress and accelerate cardiovascular disease. Furthermore, we comment on the antioxidative activity of catechin in atherosclerosis accelerated by periodontitis.

The complex and multifactorial relationship between testosterone deficiency (TD), obesity and vascular disease

Testosterone deficiency (TD) is a well-established and recognized medical condition that contributes to several co-morbidities, including metabolic syndrome, visceral obesity and cardiovascular disease (CVD). More importantly, obesity is thought to contribute to TD. This complex bidirectional interplay between TD and obesity promotes a vicious cycle, which further contributes to the adverse effects of TD and obesity and may increase the risk of CVD. Testosterone (T) therapy for men with TD has been shown to be safe and effective in ameliorating the components of the metabolic syndrome (Met S) and in contributiong to increased lean body mass and reduced fat mass and therefore contributes to weight loss. We believe that appropriate T therapy in obese men with TD is a novel medical approach to manage obesity in men with TD. Indeed, other measures of lifestyle and behavioral changes can be used to augment but not fully replace this effective therapeutic approach. It should be noted that concerns regarding the safety of T therapy remain widely unsubstantiated and considerable evidence exists supporting the benefits of T therapy. Thus, it is paramount that clinicians managing obese men with TD be made aware of this novel approach to treatment of obesity. In this review, we discuss the relationship between TD and obesity and highlight the contemporary advancement in management of obesity with pharmacological and surgical approaches, as well as utilization of T therapy and how this intervention may evolve as a novel approach to treatment of obesity in men with TD .

Diabetes mellitus related bone metabolism and periodontal disease

Diabetes mellitus and periodontal disease are chronic diseases affecting a large number of populations worldwide. Changed bone metabolism is one of the important long-term complications associated with diabetes mellitus. Alveolar bone loss is one of the main outcomes of periodontitis, and diabetes is among the primary risk factors for periodontal disease. In this review, we summarise the adverse effects of diabetes on the periodontium in periodontitis subjects, focusing on alveolar bone loss. Bone remodelling begins with osteoclasts resorbing bone, followed by new bone formation by osteoblasts in the resorption lacunae. Therefore, we discuss the potential mechanism of diabetes-enhanced bone loss in relation to osteoblasts and osteoclasts.

Non-Nutrient, Naturally Occurring Phenolic Compounds with Antioxidant Activity for the Prevention and Treatment of Periodontal Diseases

One of the main factors able to explain the pathophysiological mechanism of inflammatory conditions that occur in periodontal disease is oxidative stress. Given the emerging understanding of this relationship, host-modulatory therapies using antioxidants could be interesting to prevent or slow the breakdown of soft and hard periodontal tissues. In this context, non-nutrient phenolic compounds of various foods and plants have received considerable attention in the last decade. Here, studies focusing on the relationship between different compounds of this type with periodontal disease have been collected. Among them, thymoquinone, coenzyme Q (CoQ), mangiferin, resveratrol, verbascoside and some flavonoids have shown to prevent or ameliorate periodontal tissues damage in animal models. However evidence regarding this effect in humans is poor and only limited to topical treatments with CoQ and catechins. Along with animal experiments, in vitro studies indicate that possible mechanisms by which these compounds might exert their protective effects include antioxidative properties, oxygen and nitrogen scavenging abilities, and also inhibitory effects on cell signaling cascades related to inflammatory processes which have an effect on RNS or ROS production as well as on antioxidant defense systems.

Toll-Like Receptor 9-Mediated Inflammation Triggers Alveolar Bone Loss in Experimental Murine Periodontitis

Chronic periodontitis is a local inflammatory disease induced by a dysbiotic microbiota and leading to destruction of the tooth-supporting structures. Microbial nucleic acids are abundantly present in the periodontium, derived through release after phagocytic uptake of microbes and/or from biofilm-associated extracellular DNA. Binding of microbial DNA to its cognate receptors, such as Toll-like receptor 9 (TLR9), can trigger inflammation. In this study, we utilized TLR9 knockout (TLR9(-/-)) mice and wild-type (WT) controls in a murine model of Porphyromonas gingivalis-induced periodontitis and report the first in vivo evidence that TLR9 signaling mediates the induction of periodontal bone loss. P. gingivalis-infected WT mice exhibited significantly increased bone loss compared to that in sham-infected WT mice or P. gingivalis-infected TLR9(-/-) mice, which were resistant to bone loss. Consistent with this, the expression levels of interleukin 6 (IL-6), tumor necrosis factor (TNF), and receptor-activator of nuclear factor kappa B ligand (RANKL) were significantly elevated in the gingival tissues of the infected WT mice but not in infected TLR9(-/-) mice compared to their levels in controls. Ex vivo studies using splenocytes and bone marrow-derived macrophages revealed significantly diminished cytokine production in TLR9(-/-) cells relative to the cytokine production in WT cells in response to P. gingivalis, thereby implicating TLR9 in inflammatory responses to this organism. Intriguingly, compared to the cytokine production in WT cells, TLR9(-/-) cells exhibited significantly decreased proinflammatory cytokine production upon challenge with lipopolysaccharide (LPS) (TLR4 agonist) or Pam3Cys (TLR2 agonist), suggesting possible cross talk between TLR9, TLR4, and TLR2. Collectively, our results provide the first proof-of-concept evidence implicating TLR9-triggered inflammation in periodontal disease pathogenesis, thereby identifying a new potential therapeutic target to control periodontal inflammation.

Chemokine function in periodontal disease and oral cavity cancer

The chemotactic cytokines, or chemokines, comprise a superfamily of polypeptides with a wide range of activities that include recruitment of immune cells to sites of infection and inflammation, as well as stimulation of cell proliferation. As such, they function as antimicrobial molecules and play a central role in host defenses against pathogen challenge. However, their ability to recruit leukocytes and potentiate or prolong the inflammatory response may have profound implications for the progression of oral diseases such as chronic periodontitis, where tissue destruction may be widespread. Moreover, it is increasingly recognized that chronic inflammation is a key component of tumor progression. Interaction between cancer cells and their microenvironment is mediated in large part by secreted factors such as chemokines, and serves to enhance the malignant phenotype in oral and other cancers. In this article, we will outline the biological and biochemical mechanisms of chemokine action in host–microbiome interactions in periodontal disease and in oral cancer, and how these may overlap and contribute to pathogenesis.

Oxidative Stress and Dietary Fat Type in Relation to Periodontal Disease

Oxidative stress is one of the main factors studied to explain the pathophysiological mechanisms of inflammatory conditions, such as periodontitis. In this respect, nutrition may be of great importance. Actually, research on nutrients' effects on periodontal diseases has expanded to include those influencing the redox status, which correlates to the inflammatory process. Dietary fat or lipids are often blamed as the major source of excess energy. Consequently, when caloric intake exceeds energy expenditure, the resultant substrate-induced increase in citric acid cycle activity generates an excess of reactive oxygen species (ROS). In addition, dietary fatty acid intake influences in relative fatty acid composition of biological membranes determining its susceptibility to oxidative alterations. From this standpoint, here, we reviewed studies analyzing the dietary fat role in periodontal disease. Research data suggest that periodontal health could be achieved by main dietary strategies which include substitution of saturated fats with monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), particularly n-3 PUFA. Maybe in the future, we should analyze the diet and provide some advice to periodontitis patients to improve treatment outcomes.

Expression of Leptin and Visfatin in Gingival Tissues of Chronic Periodontitis With and Without Type 2 Diabetes Mellitus: A Study Using Enzyme-Linked Immunosorbent Assay and Real-Time Polymerase Chain Reaction

BACKGROUND

The aim of this study is to investigate the protein and gene expression of leptin and visfatin in gingival tissue from patients with chronic periodontitis (CP), patients with CP and type 2 diabetes mellitus (T2DM), and healthy individuals.

METHODS

The study includes 50 individuals: 10 healthy individuals, 20 patients with CP, and 20 patients with CP and T2DM. Plaque index, gingival index, probing depth, and clinical attachment loss were measured, and gingival biopsies were obtained. Leptin and visfatin protein expression in gingival tissues was determined using enzyme-linked immunosorbent assay, and messenger RNA (mRNA) expression was measured via real-time polymerase chain reaction.

RESULTS

The highest leptin mRNA and protein expression was observed in the control group and was significantly (P ≤0.05) different from the CP and CP+T2DM groups. Gingival tissues from patients with CP and T2DM had a significant increase in visfatin and a decrease in leptin gene and protein expression (P <0.05) compared with both controls and patients with CP.

CONCLUSION

Expression of leptin and visfatin in the gingival tissues suggests a possible role for these adipokines in the pathogenesis of CP and T2DM.

Antioxidant effects of pineapple vinegar in reversing of paracetamol-induced liver damage in mice

Background

Pineapple (Ananas comosus) was demonstrated to be hepatoprotective. This study aims to investigate the reversing effects of pineapple vinegar on paracetamol-induced liver damage in murine model.

Methods

Pineapple juice was fermented via anaerobic and aerobic fermentation to produce pineapple vinegar. Male BALB/c mice (n = 70) were separated into 7 treatment groups (n = 10). Pineapple vinegar (0.08 and 2 mL/kg BW) and synthetic vinegar were used to treat paracetamol-induced liver damage in mice. The hepatoprotective effects were determined by serum biochemistry profiles (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and triglyceride (TG)), liver antioxidant levels (ferric-reducing ability plasma (FRAP), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO), and reduced glutathione assays (GSH)) and histopathological examination with hematoxylin and eosin (H&E) staining. The effects were further evaluated by the expression levels of iNOS, NF-κB, and cytochrome P450 2E1 by quantitative real-time PCR and Western blot analyses. Vinegar samples were also tested for in vitro antioxidant (FRAP, 2,2-diphenyl-2-picrylhydrazyl (DPPH), and total phenolic content (TPC)). Soluble phenolic acid contents in the samples were identified by HPLC.

Results

Pineapple vinegar contained 169.67 ± 0.05 μg GAE/mL of TPC, with 862.61 ± 4.38 μg/mL gallic acid as the main component. Oral administration of pineapple vinegar at 2 mL/kg BW reduced serum enzyme biomarker levels, including AST (P = 0.008), ALT (P = 0.006), ALP (P₌ 0.002), and TG (P = 0.006) after 7 days of paracetamol treatment. Liver antioxidant levels such as hepatic glutathione (P = 0.003), SOD (P < 0.001), lipid peroxidation (P = 0.002) and FRAP (P <0.001) were restored after the treatment. Pineapple vinegar reduced the expressions of iNOS (P = 0.003) and NF-kB (P = 0.003) and the level of NO (P = 0.003) significantly. Pineapple vinegar also downregulated liver cytochrome P450 protein expression.

Conclusions

Oral administration of pineapple vinegar at 0.08 and 2 mL/kg BW reduced serum enzyme biomarker levels, restored liver antioxidant levels, reduced inflammatory factor expressions, and down regulated liver cytochrome P450 protein expression in paracetamol-induced liver damage in mice.

Subcutaneous vaccination with Porphyromonas gingivalis ameliorates periodontitis by modulating Th17/Treg imbalance in a murine model

To date, Porphyromonas gingivalis (P. gingivalis) vaccination has been studied only in animals, and no effective prophylactic human periodontal vaccine has been developed, with the reason for the failure of prophylactic human periodontal vaccines unknown. T helper 17 cell (Th17)/regulatory T (Treg) cell responses play an important role in the development of periodontitis, and a Th17/Treg imbalance causes the pathogenesis of periodontitis. However, whether vaccination with P. gingivalis can prevent periodontitis through modulation of the Th17/Treg imbalance remains unknown. In this study, mice were subcutaneously vaccinated with formalin-killed P. gingivalis and then orally challenged with P. gingivalis. The vaccination protected the mice from alveolar bone resorption and inflammation. These protective effects might be ascribed to downregulation of Th17 cells and interleukin (IL)-17A production, upregulation of Treg and receptor activator of nuclear factor-kappa B ligand (RANKL)(+)CD4(+)T cells, and IL-10 and transforming growth factor-β1 production, and inhibition of lymphocyte proliferation. Our findings may provide a direction for the development of a vaccine or therapy against periodontitis by alteration of the Th17/Treg imbalance.

Longitudinal relationship between metabolic syndrome and periodontal disease among Japanese adults aged ≥70 years: the Niigata Study

BACKGROUND

There has been little evaluation in longitudinal epidemiologic studies of the effect of metabolic syndrome (MetS) on periodontal status. The specific aim of this longitudinal study is to investigate whether MetS in the Japanese population could be a risk factor for periodontal disease.

METHODS

A total of 125 older adults from Japan for whom data were available for the years 2003 to 2006 were selected for the current study. Full-mouth periodontal status, measured as clinical attachment level (CAL), was recorded at baseline and in follow-up examinations. Development of periodontal disease was considered to be ≥2 teeth demonstrating a longitudinal loss of proximal attachment of ≥3 mm at the follow-up dental examination. A multivariable Poisson regression model with robust error variance was used to evaluate the association of MetS defined by the modified National Cholesterol Education Program Adult Treatment Panel III criteria with development of periodontal disease. Adjustments for sex, income, education, smoking status, number of teeth at baseline, mean CAL at baseline, pattern of visits to a dentist, and brushing frequency were considered.

RESULTS

The prevalence of MetS was 21.6% (27/125). Study participants with MetS were approximately 2.6 times more likely to develop periodontal disease (adjusted relative risk 2.58, 95% confidence interval 1.17 to 5.67) after simultaneous adjustment for other covariates.

CONCLUSIONS

These findings support the hypothesis that MetS may be a risk factor for periodontal disease in older Japanese individuals. Additional studies with larger, more diverse populations and more complete information are needed to substantiate the findings.

Dysbiosis and alterations in predicted functions of the subgingival microbiome in chronic periodontitis

Chronic periodontitis is an inflammatory disease of the periodontium affecting nearly 65 million adults in the United States. Changes in subgingival microbiota have long been associated with chronic periodontitis. Recent culture-independent molecular studies have revealed the immense richness and complexity of oral microbial communities. However, data sets across studies have not been directly compared, and whether the observed microbial variations are consistent across different studies is not known. Here, we used 16S rRNA sequencing to survey the subgingival microbiota in 25 subjects with chronic periodontal disease and 25 healthy controls and compared our data sets with those of three previously reported microbiome studies. Consistent with data from previous studies, our results demonstrate a significantly altered microbial community structure with decreased heterogeneity in periodontal disease. Comparison with data from three previously reported studies revealed that subgingival microbiota clustered by study. However, differences between periodontal health and disease were larger than the technical variations across studies. Using a prediction score and applying five different distance metrics, we observed two predominant clusters. One cluster was driven by Fusobacterium and Porphyromonas and was associated with clinically apparent periodontitis, and the second cluster was dominated by Rothia and Streptococcus in the majority of healthy sites. The predicted functional capabilities of the periodontitis microbiome were significantly altered. Genes involved in bacterial motility, energy metabolism, and lipopolysaccharide biosynthesis were overrepresented in periodontal disease, whereas genes associated with transporters, the phosphotransferase system, transcription factors, amino acid biosynthesis, and glycolysis/gluconeogenesis were enriched in healthy controls. These results demonstrate significant alterations in microbial composition and function in periodontitis and suggest genes and metabolic pathways associated with periodontal disease.

Beyond the flavour: a de-flavoured polyphenol rich extract of clove buds (Syzygium aromaticum L) as a novel dietary antioxidant ingredient

A popular kitchen spice, clove bud (Syzygium aromaticumL), was selected to derive a de-flavoured extract with a standardised polyphenolic profile (Clovinol) and was incorporated into various foods.

Telomere length attrition and chronic periodontitis: an ARIC Study nested case-control study

AIM

This nested case-control study sought to determine whether an accelerated rate of leukocyte telomere length (LTL) shortening over 6 years was associated with chronic periodontitis.

MATERIALS AND METHODS

We sampled cases (n = 178) with severe chronic periodontitis and controls (n = 178) with no/mild chronic periodontitis from the Atherosclerosis Risk in Communities study. Controls were frequency-matched to cases by study site, age, sex and race. Age ranged from 53 to 73 years. Severe chronic periodontitis was defined using the CDC-AAP case classification. LTL was measured from DNA collected at two time points, 6 years apart, with quantitative polymerase chain reaction relative to a single-copy control gene. Multiple linear regression evaluated associations between LTL measured at baseline, follow-up and change scores with severe chronic periodontitis, adjusting for potential confounders.

RESULTS

Cases had shorter LTL than controls at baseline (p = 0.03) and follow-up (p = 0.04) after adjusting for confounding. Overall there was a net reduction in LTL over time (p = 0.02). The rate of LTL did not differ between cases and controls (p = 0.80).

CONCLUSIONS

Leukocyte telomere length shortening occurred at the same rate among adults with and without severe chronic periodontitis. This suggests that LTL shortening may have occurred earlier in the life course.

Alzheimer's disease and chronic periodontitis: is there an association?

Alzheimer's disease, an affliction of old age, is one of the leading causes for dementia worldwide. Various risk factors including family history, genetics and infections have been implicated in its pathogenesis. The cognitive decline in this condition is mainly a result of the formation of amyloid deposits that provoke neuroinflammation, ultimately resulting in cell death. Recently, an association between peripheral inflammation and Alzheimer's disease was hypothesized. It was suggested that chronic systemic inflammation worsened the inflammatory processes in the brain. This was mainly attributed to increased levels of pro-inflammatory mediators, such as interleukin-1, interleukin -6 and tumor necrosis factor-α in the plasma. As chronic periodontitis is a widespread peripheral immunoinflammatory condition, it has been proposed to play a significant role in the aggravation of Alzheimer's disease. With this background, the current review focuses on the relationship between Alzheimer's disease and chronic periodontitis, and its therapeutic implications.

Lipophilic antioxidants prevent lipopolysaccharide-induced mitochondrial dysfunction through mitochondrial biogenesis improvement

Oxidative stress is implicated in several infectious diseases. In this regard, lipopolysaccharide (LPS), an endotoxic component, induces mitochondrial dysfunction and oxidative stress in several pathological events such as periodontal disease or sepsis. In our experiments, LPS-treated fibroblasts provoked increased oxidative stress, mitochondrial dysfunction, reduced oxygen consumption and mitochondrial biogenesis. After comparing coenzyme Q10 (CoQ10) and N-acetylcysteine (NAC), we observed a more significant protection of CoQ10 than of NAC, which was comparable with other lipophilic and hydrophilic antioxidants such as vitamin E or BHA respectively. CoQ10 improved mitochondrial biogenesis by activating PGC-1α and TFAM. This lipophilic antioxidant protection was observed in mice after LPS injection. These results show that mitochondria-targeted lipophilic antioxidants could be a possible specific therapeutic strategy in pharmacology in the treatment of infectious diseases and their complications.

LPS from P. gingivalis and hypoxia increases oxidative stress in periodontal ligament fibroblasts and contributes to periodontitis

Oxidative stress is characterized by an accumulation of reactive oxygen species (ROS) and plays a key role in the progression of inflammatory diseases. We hypothesize that hypoxic and inflammatory events induce oxidative stress in the periodontal ligament (PDL) by activating NOX4. Human primary PDL fibroblasts were stimulated with lipopolysaccharide from Porphyromonas gingivalis (LPS-PG), a periodontal pathogen bacterium under normoxic and hypoxic conditions. By quantitative PCR, immunoblot, immunostaining, and a specific ROS assay we determined the amount of NOX4, ROS, and several redox systems. Healthy and inflamed periodontal tissues were collected to evaluate NOX4 and redox systems by immunohistochemistry. We found significantly increased NOX4 levels after hypoxic or inflammatory stimulation in PDL cells (P < 0.001) which was even more pronounced after combination of the stimuli. This was accompanied by a significant upregulation of ROS and catalase (P < 0.001). However, prolonged incubation with both stimuli induced a reduction of catalase indicating a collapse of the protective machinery favoring ROS increase and the progression of inflammatory oral diseases. Analysis of inflamed tissues confirmed our hypothesis. In conclusion, we demonstrated that the interplay of NOX4 and redox systems is crucial for ROS formation which plays a pivotal role during oral diseases.

Relationship of clinical and microbiological variables in patients with type 1 diabetes mellitus and periodontitis

BACKGROUND

The aim of the study was to analyze how metabolic control of type 1 diabetes is related to clinical and microbiological periodontal parameters.

MATERIAL AND METHODS

The study involved 56 subjects aged from 19 to 50 years divided into 2 groups: healthy subjects (the H group), and diabetic (type 1 diabetes) patients with chronic untreated generalized periodontitis (the DM group). The glycosylated hemoglobin value (HbA1c) was determined using the UniCel DxC 800 SYNCHRON System (Beckman Coulter, USA), and the concentration in blood was measured by the turbidimetric immunoinhibition method. A molecular genetic assay (Micro-IDent plus, Germany) was used to detect periodontopathogenic bacteria in plaque samples. Periodontitis was confirmed by clinical and radiological examination.

RESULTS

Fusobacterium nucleatum, Capnocytophaga species, and Eikenella corrodens were the most frequently found bacteria in dental plaque samples (77.8%, 66.7%, and 33.4%, respectively), whereas Aggregatibacter actinomycetemcomitans was identified 40.7% less frequently in the DM group than in the H group. The strongest relationship was observed between the presence of 2 periodontal pathogens - F. nucleatum and Capnocytophaga spp. - and poorer metabolic control in type 1 diabetes patients (HbA1c) and all clinical parameters of periodontal pathology.

CONCLUSIONS

Periodontal disease was more evident in type 1 diabetic patients, and the prevalence of periodontitis was greatly increased in subjects with poorer metabolic control.

Modification of the properties of biological membrane and its protection against oxidation by Actinidia arguta leaf extract

The aim of the study was to determine the polyphenol composition and biological activity of an extract from the leaves of kiwi. Antioxidant and hemolytic activity of the extract were examined, as well as its effect on the physical properties of the erythrocyte membrane such as osmotic resistance, membrane fluidity, and packing order of its hydrophilic area. Antioxidant activity of the extract was determined in relation to the erythrocyte membrane oxidized with free radicals induced by UVB and UVC radiation and the compound AAPH. Chromatographic, spectrophotometric and fluorimetric methods were applied in the research. The obtained results showed that kiwi leaves are a rich source of polyphenolic substances, mainly catechins and their dimers, which do not induce red blood cell hemolysis but make them stronger and more resistant to changes in medium tonicity. Substances contained in the extract effectively protect erythrocyte membranes against oxidation induced by physicochemical factors, the effectiveness of the protection depending on the concentration and type of free radical inducer. In addition, the study showed that the kiwi extract increases fluidity of the erythrocyte membrane and causes an increase in packing disorder in the hydrophilic membrane area. The changes seem to be due to the presence of polyphenolic substances in the extract, mainly in the region of the polar heads of lipids, where they can form a barrier protecting the membrane against diffusion of free radicals to the membrane interior. The effects of the extract evidenced by the present research, in particular protection of the biological membrane against free radicals induced by physicochemical agents, make it a potential valuable food additive, to enrich it with polyphenolic compounds that inhibit lipid oxidation in food exposed to UVB radiation. Supplementing the organism with substances contained in kiwi leaves is expected to provide protection against many diseases that develop as a result of oxidative stress.

Association of Carotid Intima-media Thickness and Atherosclerotic Plaque with Periodontal Status

Studies have suggested an association between clinical/subclinical atherosclerosis and periodontal status. The purpose of this study was to investigate the association among maximal carotid intima-media thickness (cIMT), atherosclerotic plaque, and periodontal status in Chinese elderly patients. A cross-sectional study was conducted of 847 participants (age, 70.64 ± 9.03 yr) with ≥10 teeth. A questionnaire survey, routine biochemical tests, a periodontal examination, and maximal cIMT measurement were performed for each. Traditional risk factors for atherogenesis were considered in the statistical analysis. Mean plaque index, which reflects oral hygiene, was correlated with maximal cIMT and atherosclerotic plaque in the study sample overall (β = 0.068, p < .001; OR = 2.051, p < .001) and in euglycemic participants (β = 0.066, p = .008; odds ratio = 2.122, p = .009). In hyperglycemic participants, multiple linear regression analysis (p = .006) and multivariate logistic regression analysis (p = .025) revealed a linear and dose-dependent association between mean clinical attachment loss and maximal cIMT after adjustment for traditional risk factors. Each 1-mm increase in mean clinical attachment loss corresponded to a 0.018-mm increase in maximal cIMT. The risk of atherosclerotic plaque increased by 18.3% with each 1-mm increase in mean clinical attachment loss. Other indicators of periodontal exposure, including percentage of sites with attachment loss ≥ 3 to 5 mm (3%-5%), were also correlated with cIMT and atherosclerotic plaque in hyperglycemic patients. In this elderly population, a linear and dose-dependent association among mean clinical attachment loss, attachment loss 3% to 5%, maximal cIMT, and atherosclerotic plaque was verified in those with hyperglycemia. Poor oral hygiene was correlated with maximal cIMT and atherosclerotic plaque in all participants, including those with normal blood glucose.

Association between harmful alcohol use and periodontal status according to gender and smoking

Background

the aim of this study is to assess the association of harmful alcohol use based on the alcohol use disorders identification test (AUDIT) score with periodontal status according to gender and smoking in a representative sample of Korean adults.

Methods

This study analyzed 5,291 participants older than 19 years whose data of harmful alcohol use and periodontal status were available. Harmful alcohol use was defined by the WHO guidelines for the administration of AUDIT. The periodontal status was assessed by the Community Periodontal Index (CPI). Multivariate logistic regression analysis was performed with adjustment for socio-demographic variables, oral and general health behavior, oral health status and systemic conditions. All analyses considered a complex sampling design, and multivariate analysis was also performed in the subgroups.

Results

Multivariate logistic regression analysis revealed a marginal association between harmful alcohol use and higher CPI in the total sample. The adjusted odds ratio (OR) of harmful alcohol use was 1.16 (0.97 to 1.38) for higher CPI. Higher CPI was significantly associated with harmful alcohol use in men (OR: 1.28; 95% CI: 1.03-1.60) and non-smokers (OR: 1.29; 95% CI: 1.06-1.57).

Conclusion

Periodontal status is significantly associated with harmful alcohol use in men and non-smokers in a representative sample of Korean adults.

A high-fiber, low-fat diet improves periodontal disease markers in high-risk subjects: a pilot study

Periodontal disease is related to aging, smoking habits, diabetes mellitus, and systemic inflammation. However, there remains limited evidence about causality from intervention studies. An effective diet for prevention of periodontal disease has not been well established. The current study was an intervention study examining the effects of a high-fiber, low-fat diet on periodontal disease markers in high-risk subjects. Forty-seven volunteers were interviewed for recruitment into the study. Twenty-one volunteers with a body mass index of at least 25.0 kg/m(2) or with impaired glucose tolerance were enrolled in the study. After a 2- to 3-week run-in period, subjects were provided with a test meal consisting of high fiber and low fat (30 kcal/kg of ideal body weight) 3 times a day for 8 weeks and followed by a regular diet for 24 weeks. Four hundred twenty-five teeth from 17 subjects were analyzed. Periodontal disease markers assessed as probing depth (2.28 vs 2.21 vs 2.13 mm; P < .0001), clinical attachment loss (6.11 vs 6.06 vs 5.98 mm; P < .0001), and bleeding on probing (16.2 vs 13.2 vs 14.6 %; P = .005) showed significant reductions after the test-meal period, and these improvements persisted until the follow-up period. Body weight (P < .0001), HbA1c (P < .0001), and high-sensitivity C-reactive protein (P = .038) levels showed improvement after the test-meal period; they returned to baseline levels after the follow-up period. In conclusion, treatment with a high-fiber, low-fat diet for 8 weeks effectively improved periodontal disease markers as well as metabolic profiles, at least in part, by effects other than the reduction of total energy intake.

Pepsin-pancreatin protein hydrolysates from extruded amaranth inhibit markers of atherosclerosis in LPS-induced THP-1 macrophages-like human cells by reducing expression of proteins in LOX-1 signaling pathway

BACKGROUND

Atherosclerosis is considered a progressive disease that affects arteries that bring blood to the heart, to the brain and to the lower end. It derives from endothelial dysfunction and inflammation, which play an important role in the thrombotic complications of atherosclerosis. Cardiovascular disease is the leading cause of death around the world and one factor that can contribute to its progression and prevention is diet. Our previous study found that amaranth hydrolysates inhibited LPS-induced inflammation in human and mouse macrophages by preventing activation of NF-κB signaling. Furthermore, extrusion improved the anti-inflammatory effect of amaranth protein hydrolysates in both cell lines, probably attributed to the production of bioactive peptides during processing. Therefore, the objective of this study was to compare the anti-atherosclerotic potential of pepsin-pancreatin hydrolysates from unprocessed and extruded amaranth in THP-1 lipopolysaccharide-induced human macrophages and suggest the mechanism of action.

RESULTS

Unprocessed amaranth hydrolysate (UAH) and extruded amaranth hydrolysate (EAH) showed a significant reduction in the expression of interleukin-4 (IL-4) (69% and 100%, respectively), interleukin-6 (IL-6) (64% and 52%, respectively), interleukin-22 (IL-22) (55% and 70%, respectively). Likewise, UAH and EAH showed a reduction in the expression of monocyte-chemo attractant protein-1 (MCP-1) (35% and 42%, respectively), transferrin receptor-1 (TfR-1) (48% and 61%, respectively), granulocyte-macrophage colony-stimulating factor (GM-CSF) (59% and 63%, respectively), and tumor necrosis factor-α (TNF-α) (60% and 63%, respectively). Also, EAH reduced the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) (27%), intracellular adhesion molecule-1 (ICAM-1) (28%) and matrix metalloproteinase-9 (MMP-9) (19%), important molecular markers in the atherosclerosis pathway. EAH, led to a reduction of 58, 52 and 79% for LOX-1, ICAM-1 and MMP-9, respectively, by confocal microscopy.

CONCLUSIONS

Extruded amaranth hydrolysate showed potential anti-atherosclerotic effect in LPS-induced THP-1 human macrophage-like cells by reducing the expression of proteins associated with LOX-1 signaling pathway.