The oral-gut microbiome axis in inflammatory bowel disease: from inside to insight

Inflammatory bowel disease (IBD) is an idiopathic and persistent inflammatory illness of the bowels, leading to a substantial burden on both society and patients due to its high incidence and recurrence. The pathogenesis of IBD is multifaceted, partly attributed to the imbalance of immune responses toward the gut microbiota. There is a correlation between the severity of the disease and the imbalance in the oral microbiota, which has been discovered in recent research highlighting the role of oral microbes in the development of IBD. In addition, various oral conditions, such as angular cheilitis and periodontitis, are common extraintestinal manifestations (EIMs) of IBD and are associated with the severity of colonic inflammation. However, it is still unclear exactly how the oral microbiota contributes to the pathogenesis of IBD. This review sheds light on the probable causal involvement of oral microbiota in intestinal inflammation by providing an overview of the evidence, developments, and future directions regarding the relationship between oral microbiota and IBD. Changes in the oral microbiota can serve as markers for IBD, aiding in early diagnosis and predicting disease progression. Promising advances in probiotic-mediated oral microbiome modification and antibiotic-targeted eradication of specific oral pathogens hold potential to prevent IBD recurrence.

Key periodontal pathogens may mediate potential pathogenic relationships between periodontitis and crohn's disease

BACKGROUND

Crohn's disease (CD)-associated periodontitis is common. However, the role of periodontal pathogens in the Coexistence of CD and periodontal disease remains unclear.

METHODS

To investigate the potential relationship mediated by periodontal pathogens between periodontitis and CD, we collected salivary samples from healthy participants (H group, n = 12), patients with CD (Ch group, n = 10), patients with periodontitis (Ps group, n = 12), and patients with Coexistence of CD and periodontal disease (Cp group, n = 12) and analyzed them by 16 S rRNA sequencing.

RESULTS

Patients with Coexistence of CD and periodontal disease had increased levels of Fusobacterium, Actinomyces, Leptotrichia, and Prevotella, which correlated with the severity of periodontitis. Conversely, the levels of Streptococcus, Neisseria, Haemophilus, and Gemella, which decreased in Coexistence of CD and periodontal disease, were negatively correlated with the severity of periodontitis. To further investigate the role of periodontal pathogens in CD development, representative periodontal pathogens causing periodontitis, Porphyromonas gingivalis and Fusobacterium nucleatum, were administered to mice. These pathogens migrate to, and colonize, the gut, accelerating CD progression and aggravating colitis, and even systemic inflammation. In vitro experiments using a Caco-2/periodontal pathogen coculture revealed that P. gingivalis and F. nucleatum increased intestinal permeability by directly disrupting the tight junctions of intestinal epithelial cells.

CONCLUSION

Our findings strongly suggest that periodontal pathogens play a role in the relationship between periodontitis and CD. These results provide a basis for understanding the pathogenesis of Coexistence of CD and periodontal disease and may lead to the development of novel therapeutic strategies.

Characterization of the intestinal transport mechanism of polystyrene microplastics (MPs) and the potential inhibitory effect of green tea extracts on MPs intestinal absorption

The aims of the current study included characterizing the intestinal transport mechanism of polystyrene microplastics (MPs) with different charges and sizes in the intestinal epithelial cell model and determining the inhibitory effect of green tea extracts (GTEs) on the intestinal absorption of MPs in Caco-2 cells. The smaller sizes, which included diameters of 0.2 μm, of amine-modified MPs compared to either larger size (1 μm diameter, or carboxylate-MPs (0.2 and 1 μm diameter) significantly lowered the cell viability of caco-2 cells that were measured by MTT assay (p < 0.05). The transported amount (particles/mL of the cell media) of amine-modified MPs by the Caco-2 cell, was not dependent according to the concentrations, energy, or temperature, but it was higher than the carboxylate-modified MPs. The co-treatment of GTEs with the amine-modified MPs inhibited Caco-2 cell cytotoxicity as well as reduced the production of intracellular reactive oxygen species (ROS) in HepG2 generated by the exposure of amine-modified MPs. The GTEs co-treatment also increased trans-epithelial electrical resistances (TEER) and reduced the transportation of Lucifer Yellow via the Caco-2 monolayer compared to only the amine-modified MPs exposure. The GTEs treatment led to a decrease in the number of amine-modified MPs transported to the basal side of the Caco-2 monolayer. The results from our study suggest that the consumption of GTEs could enhance the intestinal barrier function by recovering intestinal epithelial cell damage induced by MPs, which resulted in a decrease of the intestinal absorption of MPs.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction

This study evaluates the effects of a green tea (Camellia sinensis) and hyaluronic acid gel on fibroblast activity and alveolar bone repair following third molar extractions. By examining the gene expression related to cell survival, proliferation, and angiogenesis, the study bridges in vitro findings with clinical outcomes in a split-mouth randomized trial. Human fibroblasts were exposed to the treatment gel, analysing gene expression through RT-qPCR. Twenty participants undergoing bilateral third molar extractions received the test gel on one side and a placebo on the other. Assessments included patient-reported outcomes, professional evaluations, and radiographic analyses at multiple postoperative intervals. The test gel significantly enhanced AKT, CDKs, and VEGF gene expressions, indicating a positive effect on angiogenesis and cell proliferation. Clinically, it resulted in reduced exudate, swelling, and secondary interventions, with radiographs showing improved alveolar bone density after 90 days. The green tea and hyaluronic acid gel significantly improves soft tissue and bone healing post-extraction, offering a promising adjunctive therapy for enhancing postoperative recovery. This gel represents a novel adjuvant treatment option for facilitating improved healing outcomes after third molar extractions, highlighting its potential utility in clinical dental practice.

Loricrin and Cytokeratin Disorganisation in Severe Forms of Periodontitis

OBJECTIVE

The aim of this research was to investigate the role of the cornified epithelium, the outermost layer of the oral mucosa, engineered to prevent water loss and microorganism invasion, in severe forms of periodontitis (stage III or IV, grade C).

METHODS

Porphyromonas gingivalis, a major periodontal disease pathogen, can affect cornified epithelial protein expression through chronic activation of signal transducer and activator of transcription 6 (Stat6). We used a mouse model, Stat6VT, that mimics this to determine the effects of barrier defect on P gingivalis-induced inflammation, bone loss, and cornified epithelial protein expression, and compared histologic and immunohistologic findings with tissues obtained from human controls and patients with stage III and IV, grade C disease. Alveolar bone loss in mice was assessed using micro-computerised tomography, and soft tissue morphology was qualitatively and semi-quantitatively assessed by histologic examination for several proteins, including loricrin, filaggrin, cytokeratin 1, cytokeratin 14, a proliferation marker, a pan-leukocyte marker, as well as morphologic signs of inflammation. Relative cytokine levels were measured in mouse plasma by cytokine array.

RESULTS

In the tissues from patients with periodontal disease, there were greater signs of inflammation (rete pegs, clear cells, inflammatory infiltrates) and a decrease and broadening of expression of loricrin and cytokeratin 1. Cytokeratin 14 expression was also broader and decreased in stage IV. P gingivalis-infected Stat6VT mice showed greater alveolar bone loss in 9 out of 16 examined sites, and similar patterns of disruption to human patients in expression of loricrin and cytokeratins 1 and 14. There were also increased numbers of leukocytes, decreased proliferation, and greater signs of inflammation compared with P gingivalis-infected control mice.

CONCLUSIONS

Our study provides evidence that changes in epithelial organisation can exacerbate the effects of P gingivalis infection, with similarities to the most severe forms of human periodontitis.

Epigallocatechin gallate (EGCG) alleviates the inflammatory response and recovers oral microbiota in acetic acid-induced oral inflammation mice

The oral microbiota, the second largest microbiome in the human body, plays an integral role in maintaining both the local oral and systemic health of the host. Oral microecological imbalances have been identified as a potential risk factor for numerous oral and systemic diseases. As a representative component of tea, epigallocatechin gallate (EGCG) has demonstrated inhibitory effects on most pathogens in single-microbial models. In this study, the regulatory effect of EGCG on more complex oral microbial systems was further explored through a mouse model of acetic acid-induced oral inflammation. Acetic acid induces histological damage in the cheek pouch, tongue, and throat, such as broken mucosa, submucosal edema, and muscular disorders. These detrimental effects were ameliorated significantly following EGCG treatment. Additionally, EGCG reduced the levels of the inflammatory cytokines interleukin-6 and tumor necrosis factor-α to alleviate the inflammation of the tongue, cheek pouch, and throat. According to the 16S rDNA gene sequencing data, EGCG treatment contributed to increased diversity of the oral microbiota and the reversal of oral microecological disorder. This study demonstrates the regulatory effect of EGCG on dysregulated oral microbiota, providing a potential option for the prevention and treatment of oral-microbiota-associated diseases.

Tea Polyphenols Protects Tracheal Epithelial Tight Junctions in Lung during Actinobacillus pleuropneumoniae Infection via Suppressing TLR-4/MAPK/PKC-MLCK Signaling

Actinobacillus pleuropneumoniae (APP) is the causative pathogen of porcine pleuropneumonia, a highly contagious respiratory disease in the pig industry. The increasingly severe antimicrobial resistance in APP urgently requires novel antibacterial alternatives for the treatment of APP infection. In this study, we investigated the effect of tea polyphenols (TP) against APP. MIC and MBC of TP showed significant inhibitory effects on bacteria growth and caused cellular damage to APP. Furthermore, TP decreased adherent activity of APP to the newborn pig tracheal epithelial cells (NPTr) and the destruction of the tight adherence junction proteins β-catenin and occludin. Moreover, TP improved the survival rate of APP infected mice but also attenuated the release of the inflammation-related cytokines IL-6, IL-8, and TNF-α. TP inhibited activation of the TLR/MAPK/PKC-MLCK signaling for down-regulated TLR-2, TLR4, p-JNK, p-p38, p-PKC-α, and MLCK in cells triggered by APP. Collectively, our data suggest that TP represents a promising therapeutic agent in the treatment of APP infection.

Nano-Catechin Gel as a Sustained Release Antimicrobial Agent against Clinically Isolated Porphyromonas gingivalis for Promising Treatment of Periodontal Diseases

During the last two decades, new drug delivery strategies have been invented that have been able to solve microbial resistance against antibiotics. The goal of the current report was to assess the antimicrobial effects of nano-catechin gels against clinically isolated Porphyromonas gingivalis, one of the main causes of periodontal disease. Catechin-loaded chitosan nanoparticles were prepared by adding a catechin solution to a chitosan solution. Then, the mean particle size and the mean surface charge (zeta potential) of the nanoparticles were detected through photon correlation spectroscopy and zeta sizer, respectively. Nano-catechin gels (1000, 500, 250, 125, 62.5, and 31.2 µg/mL) were prepared, and the antimicrobial assay was performed against clinically isolated Porphyromonas gingivalis (P. gingivalis). The clinically obtained P. gingivalis isolates were obtained from periodontitis patients (N = 15). The consequences are specified as descriptive indices. The normality of data was detected by the Shapiro-Wilk test. Then, to compare the data between groups (with a p value < 0.05 as the significance level), SPSS software (version 22) was used via a Mann-Whitney U test. The results showed a nanometer particle size range and a positive zeta potential for the prepared nanoparticles. All the concentrations (1000, 500, 250, 125, 62.5, and 31.2 µg/mL) of nano-catechin gels showed sustained release patterns and were non-toxic against dental pulp stem cells as well. There were no significant differences between the minimal inhibitory concentrations (MICs) for nano-catechin gel (test group) and Chlorhexidine (control group) against 15 isolates (p > 0.05). Then, two groups showed similar antimicrobial effects. The similar antimicrobial activity of catechin nanoparticles and Chlorhexidine, as a potent antimicrobial agents, against clinically isolated P. gingivalis showed that catechin nanoparticles can be used as a potent antimicrobial material for the treatment of periodontal diseases in the near future.

Lactobacillus reuteri for chronic periodontitis: focus on underlying mechanisms and future perspectives

Chronic periodontitis is a common oral disorder caused by pathogenic bacteria. Despite the wide use of antibiotics as the conventional adjunctive treatment, the challenges of increased antibiotic resistance and limited therapeutic effect receive considerable attention and the developments of alternative treatments gain increasing consideration. Growing evidence showed that Lactobacillus reuteri (LR) may represent a promising alternative adjunct for chronic periodontitis. It can attenuate inflammation and reduce tissue disruption. LR-assisted treatment has been shown to be effective and relatively safe in multiple clinical trials, and accumulating evidence suggests its significant biological roles. In the current review, we focus on capturing the underlying mechanisms of LR involved in chronic periodontitis, thereby representing a scientific foundation for LR-assisted therapy. Furthermore, we point out the challenges and future directions for further clinical trials to improve the clinical applicability for LR.

The Association between Habitual Green Tea Consumption and Comprehensive Frailty as Assessed by Kihon Checklist Indexes among an Older Japanese Population

Background: It is unclear whether habitual green tea consumption is related to comprehensive frailty. Objectives: We conducted this study to investigate this relationship among an elderly Japanese population. Methods: This was a cross-sectional study of baseline data from 2012. The study included 5668 Japanese participants (2766 men and 2902 women aged 65 years or older). The subjects completed a validated self-administered food frequency questionnaire that included questions on their green tea consumption. We evaluated comprehensive frailty using a 25-item Kihon Checklist (KCL), which comprised seven domains (instrumental activities of daily living (IADL), physical function, malnutrition, oral or eating function, socialization and housebound, cognitive function, and depression). Frailty was defined as a KCL score greater than or equal to seven. Results: We found that a higher consumption of green tea was associated with a lower prevalence of comprehensive frailty in both sexes. Further age-stratified analysis showed that a higher consumption of green tea among women was associated with a lower prevalence of comprehensive frailty, regardless of age. In men, however, this association was found only in the older age groups. An analysis of the association between green tea consumption and the frailty subdomains showed that green tea consumption was associated with a lower prevalence of oral dysfunction and cognitive problems in both sexes. In addition, only in women was higher green tea consumption found to be associated with a lower prevalence of IADL and mobility-related disability problems. Conclusions: Green tea consumption is inversely associated with the prevalence of comprehensive frailty in Japanese men and women. Longitudinal studies are required to confirm this association.

Therapeutic effects of green tea as an antioxidant on oral health- A review

Green tea has protective effects against various diseases such as malignancies, cardiovascular and metabolic disorders. Green tea has been suggested to promote periodontal health by reducing inflammation, preventing the resorption of bones and restricting the growth of certain periodontal-related bacteria. Green tea has antioxidant, carcinogenic, antimicrobial and non-inflammatory properties. This traditional drink is also used to treat systemic chronic diseases, including carcinoma. Recent studies have shown that host immuno-inflammatory reactions, in addition to microbial activity, are more likely to destroy oral tissues. In such cases, green tea is considered to be a natural preventive and curative agent. The potential benefits of green tea and its polyphenols in oral health is capturing the interest of the researchers; hence, this review discusses the therapeutic effects of green tea in the prevention of periodontal and oral diseases.

A comprehensive review of the influence of Epigallocatechin gallate on Sjögren's syndrome associated molecular regulators of exocytosis (Review)

Sjögren's syndrome (SS) is an autoimmune disorder that affects the salivary glands, leading to reduced secretory functions and oral and ocular dryness. The salivary glands are composed of acinar cells that are responsible for the secretion and production of secretory granules, which contain salivary components, such as amylase, mucins and immunoglobulins. This secretion process involves secretory vesicle trafficking, docking, priming and membrane fusion. A failure during any of the steps in exocytosis in the salivary glands results in the altered secretion of saliva. Soluble N-ethylmaleimide-sensitive-factor attachment protein receptors, actin, tight junctions and aquaporin 5 all serve an important role in the trafficking regulation of secretory vesicles in the secretion of saliva via exocytosis. Alterations in the expression and distribution of these selected proteins leads to salivary gland dysfunction, including SS. Several studies have demonstrated that green tea polyphenols, most notably Epigallocatechin gallate (EGCG), possess both anti-inflammatory and anti-apoptotic properties in normal human cells. Molecular, cellular and animal studies have indicated that EGCG can provide protective effects against autoimmune and inflammatory reactions in salivary glands in diseases such as SS. The aim of the present article is to provide a comprehensive and up-to-date review on the possible therapeutic interactions between EGCG and the selected molecular mechanisms associated with SS.

Local Oral Delivery Agents with Anti-Biofilm Properties for the Treatment of Periodontitis and Peri-Implantitis. A Narrative Review

Despite many discoveries over the past 20 years regarding the etiopathogenesis of periodontal and peri-implant diseases, as well as significant advances in our understanding of microbial biofilms, the incidence of these pathologies continues to rise. For this reason, it was clear that other strategies were needed to eliminate biofilms. In this review, the literature database was searched for studies on locally delivered synthetic agents that exhibit anti-biofilm properties and their potential use in the treatment of two important oral diseases: periodontitis and peri-implantitis.

Molecular mechanisms and applications of tea polyphenols: A narrative review

Tea is a worldwide popular drink with high nutritional and medicinal values as it is rich in nutrients, such as polyphenols, amino acids, vitamins, glycosides, and so on. Among them, tea polyphenols (TPs) are the current research hotspot. TPs are known to have multiple biological activities such as anti-oxidation, anti-tumor, anti-inflammation, anti-bacteria, lowering lipid, and liver protection. By reviewing a large number of literatures, we explained the mechanism of TPs exerting biological activity and a wide range of applications. We also discussed the deficiencies and development potential of TPs, in order to provide theoretical reference and scientific basis for the subsequent development and utilization of TPs. PRACTICAL APPLICATIONS: We summarized the bioactivity mechanisms of TPs in anti-tumor, anti-oxidation, antibacterial, anti-inflammatory, lipid-lowering, and liver protection, focused on its application fields in food and medicine, and discussed the deficiency and development potential of current research on TPs, so as to provide a certain convenient way for scholars studying TPs. It is expected to contribute to the subsequent discovery of biological activity and the broadening of the field of TPs.

Green Tea from the Far East to the Drug Store: Focus on the Beneficial Cardiovascular Effects

Cardiovascular diseases (CVD) are the leading cause of death worldwide. Evidence from observational and randomized controlled studies showing the potential benefits of green tea on lowering CVD risk has been emerging rapidly during the past few decades. These benefits include reduced risk for major cardiovascular events, lowering of blood pressure, decreased LDL cholesterol levels and weight loss. At the same time, the understanding of the physiological mechanisms behind these alterations is advancing. Consumption of green tea originated from China thousands of years ago, but since then, it expanded all over the world. Recent advances in understanding the role of tea polyphenols, mainly catechins, as mediators of tea's health benefits, have caused the emergence of various types of green tea extracts (GTE) on the market. While taking green tea is generally considered safe, there are concerns about the safety of using tea extracts. The present article reviews the current evidence of green tea consumption leading to reduced CVD risk, its potential biological mechanisms and the safety of using GTE.

Deacidification of Cranberry Juice Reduces Its Antibacterial Properties against Oral Streptococci but Preserves Barrier Function and Attenuates the Inflammatory Response of Oral Epithelial Cells

Cranberry (Vaccinium macrocarpon) may be a potent natural adjuvant for the prevention of oral diseases due to its anti-adherence, anti-cariogenic, and anti-inflammatory properties. However, the high titrable acidity of cranberry juice (CJ) has been reported to cause gastrointestinal discomfort, leading consumers to restrict their intake of this beverage. Electrodialysis with a bipolar membrane (EDBM) can reduce the organic acid content of CJ while retaining the flavonoids associated with potential health benefits. This study aimed to assess how the deacidification of CJ by EDBM impacts the antibacterial properties of the beverage against cariogenic (Streptococcus mutans, Streptococcus sobrinus) and commensal (Streptococcus gordonii, Streptococcus oralis, Streptococcus salivarius) streptococci, and how it affects oral epithelial barrier function and inflammatory response in an in vitro model. The removal of organic acids from CJ (deacidification rate ≥42%) reduced the bactericidal activity of the beverage against planktonic S. mutans and S. gordonii after a 15-min exposure, whereas only the viability of S. gordonii was significantly impacted by CJ deacidification rate when the bacteria were embedded in a biofilm. Moreover, conditioning saliva-coated hydroxyapatite with undiluted CJ samples significantly lowered the adherence of S. mutans, S. sobrinus, and S. oralis. With respect to epithelial barrier function, exposure to CJ deacidified at a rate of ≥19% maintained the integrity of a keratinocyte monolayer over the course of 24 h compared to raw CJ, as assessed by the determination of transepithelial electrical resistance (TER) and fluorescein isothiocyanate-conjugated dextran paracellular transport. These results can be in part attributed to the inability of the deacidified CJ to disrupt two tight junction proteins, zonula occludens-1 and occludin, following exposure, unlike raw CJ. Deacidification of CJ impacted the secretion of IL-6, but not of IL-8, by oral epithelial cells. In conclusion, deacidification of CJ appears to provide benefits with respect to the maintenance of oral health.

Porphyromonas gingivalis survival skills: Immune evasion

Periodontitis is a chronic inflammatory condition that destroys the tooth-supporting tissues and eventually leads to tooth loss. As one of the most prevalent oral conditions, periodontitis endangers the oral health of 70% of people throughout the world. Periodontitis is also related to various systemic diseases, such as diabetes mellitus, atherosclerosis, and rheumatoid arthritis, which not only has a great impact on population health status and the quality of life but also increases the social burden. Porphyromonas gingivalis (P. gingivalis) is a gram-negative oral anaerobic bacterium that plays a key role in the pathogenesis of periodontitis. Porphyromonas gingivalis can express various of virulence factors to overturn innate and adaptive immunities, which makes P. gingivalis survive and propagate in the host, destroy periodontal tissues, and have connection to systemic diseases. Porphyromonas gingivalis can invade into and survive in host tissues by destructing the gingival epithelial barrier, internalizing into the epithelial cells, and enhancing autophagy in epithelial cells. Deregulation of complement system, degradation of antibacterial peptides, and destruction of phagocyte functions facilitate the evasion of P. gingivalis. Porphyromonas gingivalis can also suppress adaptive immunity, which allows P. gingivalis to exist in the host tissues and cause the inflammatory response persistently. Here, we review studies devoted to understanding the strategies utilized by P. gingivalis to escape host immunity. Methods for impairing P. gingivalis immune evasion are also mentioned.

Ingestion of Porphyromonas gingivalis exacerbates colitis via intestinal epithelial barrier disruption in mice

OBJECTIVE

This study aimed to evaluate the effects of ingested periodontal pathogens on experimental colitis in mice and to elucidate its underlying mechanisms.

BACKGROUND

Inflammatory bowel disease (IBD) is defined as a chronic intestinal inflammation that results in damage to the gastrointestinal tract. Epidemiological studies have shown an association between IBD and periodontitis. Although a large number of ingested oral bacteria reach gastrointestinal tract constantly, the effect of ingested periodontal pathogens on intestinal inflammation is still unknown.

METHODS

Experimental colitis was induced by inclusion of dextran sodium sulfate solution in drinking water of the mice. Major periodontal pathogens (Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum) were administered orally every day during the experiment. The severity of colitis between the groups was compared. In vitro studies of the intestinal epithelial cell line were conducted to explore the molecular mechanisms by which periodontal pathogens affect the development of colitis.

RESULTS

The oral administration of P. gingivalis significantly increased the severity of colitis when compared to other pathogens in the DSS-induced colitis model. The ingested P. gingivalis disrupted the colonic epithelial barrier by decreasing the expression of tight junction proteins in vivo. In vitro permeability assays using the intestinal epithelial cell line suggested the P. gingivalis-specific epithelial barrier disruption. The possible involvement of gingipains in the exacerbation of colitis was implied by using P. gingivalis lacking gingipains.

CONCLUSION

Porphyromonas gingivalis exacerbates gastrointestinal inflammation by directly interacting with the intestinal epithelial barrier in a susceptible host.

Effects of a tart cherry (Prunus cerasus L.) phenolic extract on Porphyromonas gingivalis and its ability to impair the oral epithelial barrier

Periodontal diseases, including gingivitis and periodontitis, are a global oral health problem. Porphyromonas gingivalis, a key pathogen involved in the onset of periodontitis, is able to colonize the subgingival epithelium and invade the underlying connective tissue due to the contribution of cysteine proteases known as gingipains. In this study, we investigated the effects of a phenolic extract prepared from tart cherry (Prunus cerasus L.) juice on the growth, adherence, and protease activity of P. gingivalis. We also assessed the protective effect of the tart cherry extract on the disruption of the oral epithelial barrier induced by P. gingivalis. The tart cherry extract that contains procyanidins and quercetin and its derivatives (rutinoside, glucoside) as the most important phenolic compounds attenuated P. gingivalis growth, reduced adherence to an experimental basement membrane matrix model, and decreased the protease activities of P. gingivalis. The tart cherry extract also exerted a protective effect on the integrity of the oral epithelial barrier in an in vitro model infected with P. gingivalis. More specifically, the extract prevented a decrease in transepithelial electrical resistance as well as the destruction of tight junction proteins (zonula occludens-1 and occludin). These results suggest that the tart cherry phenolic extract may be a promising natural product for the treatment of periodontitis through its ability to attenuate the virulence properties of P. gingivalis and curtail the ability of this pathogen to impair the oral epithelial barrier.

Proanthocyanidins and Flavan-3-Ols in the Prevention and Treatment of Periodontitis-Antibacterial Effects

Flavan-3-ols and their oligomeric forms called proanthocyanidins are polyphenolic compounds occurring in several foodstuffs and in many medicinal herbs. Their consumption is associated with numerous health benefits. They exhibit antioxidant, anti-inflammatory, cytoprotective, as well as antimicrobial activity. The latter property is important in the prevention and treatment of periodontal diseases. Periodontitis is a multifactorial polymicrobial infection characterized by a destructive inflammatory process affecting the periodontium. Using non-toxic and efficient natural products such as flavanol derivatives can significantly contribute to alleviating periodontitis symptoms and preventing the disease’s progress. Therefore, a comprehensive systematic review of proanthocyanidins and flavan-3-ols in the prevention and treatment of periodontitis was performed. The present paper reviews the direct antibacterial effects of these compounds against periodontic pathogens. The immunomodulatory effects, including animal and clinical studies, are included in a separate, parallel article. There is significant evidence supporting the importance of the antibacterial action exerted by proanthocyanidins from edible fruits, tea, and medicinal herbs in the inhibition of periodontitis-causing pathogens.

Antioxidant Molecules from Plant Waste: Extraction Techniques and Biological Properties

The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical industries, and they exhibit multiple biological properties including antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties. The aforementioned has increased studies on the recovery of antioxidant compounds using green technologies to value plant waste, since they represent more efficient and sustainable processes. In this review, the main antioxidant molecules from plants are briefly described and the advantages and disadvantages of the use of conventional and green extraction technologies used for the recovery and optimization of the yield of antioxidant naturals are detailed; finally, recent studies on biological properties of antioxidant molecules extracted from plant waste are presented here.

Tea polyphenols inhibit the growth and virulence of ETEC K88

Diarrhea caused by Enterotoxigenic Escherichia coli (ETEC) causes high levels of morbidity and mortality in neonatal piglets. Owing to the abuse of antibiotics and emergence of drug resistance, antibiotics are no longer considered only beneficial, but also potentially harmful drugs. Supplements that can inhibit the growth of bacteria are expected to replace antibiotics. Tea polyphenols have numerous important biological functions, including antibacterial, antiviral, antioxidative, anti-inflammatory, and antihypertensive effects. We investigated the role of tea polyphenols in ETEC K88 infection using a mouse model. Pretreating with tea polyphenols attenuated the symptoms induced by ETEC K88. Furthermore, in a cell adherence assay, tea polyphenols inhibited ETEC K88 adherence to IPEC-J2 cells. When cells were infected with ETEC K88, mRNA and protein levels of claudin-1 were significantly decreased compared with those of control cells. However, when cells were pretreated with tea polyphenols, claudin-1 mRNA and protein levels were higher than those in cells without pretreatment upon cell infection with ETEC K88. TLR2 mRNA levels were also higher following cell infection with ETEC K88 when cells were pretreated with tea polyphenols. These data revealed that tea polyphenols could increase the barrier integrity of IPEC-J2 cells by upregulating expression of claudin-1 through activation of TLR2. Tea polyphenols had beneficial effects on epithelial barrier function. Therefore, tea polyphenols could be used as a novel strategy to control and treat pig infections caused by ETEC K88.

Relationship between Wine Consumption, Diet and Microbiome Modulation in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder leading to the most common form of dementia in elderly people. Modifiable dietary and lifestyle factors could either accelerate or ameliorate the aging process and the risk of developing AD and other age-related morbidities. Emerging evidence also reports a potential link between oral and gut microbiota alterations and AD. Dietary polyphenols, in particular wine polyphenols, are a major diver of oral and gut microbiota composition and function. Consequently, wine polyphenols health effects, mediated as a function of the individual's oral and gut microbiome are considered one of the recent greatest challenges in the field of neurodegenerative diseases as a promising strategy to prevent or slow down AD progression. This review highlights current knowledge on the link of oral and intestinal microbiome and the interaction between wine polyphenols and microbiota in the context of AD. Furthermore, the extent to which mechanisms bacteria and polyphenols and its microbial metabolites exert their action on communication pathways between the brain and the microbiota, as well as the impact of the molecular mediators to these interactions on AD patients, are described.

A Dual Zinc plus Arginine formulation attenuates the pathogenic properties of Porphyromonas gingivalis and protects gingival keratinocyte barrier function in an in vitro model

Background and objectives

Porphyromonas gingivalis, a late colonizer of the periodontal biofilm, has been strongly associated with the chronic form of periodontitis. The aim of this study was to investigate the effects of a Dual Zinc plus Arginine formulation (aqueous solution and dentifrice) on the pathogenic properties of P. gingivalis and the barrier function of an in vitro gingival epithelium model.

Results

The Dual Zinc plus Arginine aqueous solution and dentifrice inhibited the hemolytic and proteolytic activities of P. gingivalis. The Dual Zinc plus Arginine aqueous solution and dentifrice enhanced the barrier function of an in vitro gingival epithelium model as determined by a time-dependent increase in transepithelial electrical resistance and decrease in paracellular permeability. This was associated with an increased immunolabeling of two important tight junction proteins: zonula occludens-1 and occludin. The deleterious effects of P. gingivalis on keratinocyte barrier function as well as the ability of the bacterium to translocate through a gingival epithelium model were attenuated in the presence of either Dual Zinc plus Arginine aqueous solution or dentifrice.

Conclusions

The Dual Zinc plus Arginine formulation may offer benefits for patients affected by periodontal disease through its ability to attenuate the pathogenic properties of P. gingivalis and promote keratinocyte barrier function.

[Research progress on the regulation of phenolic compounds of traditional Chinese herbs on oral microbes]

Phenolic compounds are widely found in natural Chinese medicinal plants and have excellent pharmacological properties, such as antioxidation and anti-inflammation. They are the main pharmacological components of many medicinal Chinese herbs. Oral microbiota, especially its composition and metabolism, is highly related to the balance of oral microecology and plays a key role in the occurrence and development of oral diseases. Recent studies have shown that phenolic compounds of traditional Chinese herbs can prevent and treat oral diseases, such as caries, periodontal disease, and oral mucosal infection, by regulating the composition, metabolites, and virulence of oral microorganisms. This review will summarize and discuss the regulation of phenolic compounds on oral microbes.

Gingival epithelial barrier: regulation by beneficial and harmful microbes

The gingival epithelium acts as a physical barrier to separate the biofilm from the gingival tissue, providing the first line of defense against bacterial invasion in periodontal disease. Disruption of the gingival epithelial barrier, and the subsequent penetration of exogenous pathogens into the host tissues, triggers an inflammatory response, establishing chronic infection. Currently, more than 700 different bacterial species have been identified in the oral cavity, some of which are known to be periodontopathic. These bacteria contribute to epithelial barrier dysfunction in the gingiva by producing several virulence factors. However, some bacteria in the oral cavity appear to be beneficial, helping gingival epithelial cells maintain their integrity and barrier function. This review aims to discuss current findings regarding microorganism interactions and epithelial barrier function in the oral cavity, with reference to investigations in the gut, where this interaction has been extensively studied.

Influence of adjuvant therapy with green tea extract in the treatment of experimental periodontitis

AIM

This study evaluated the effects of topical green tea extract solution (GTE) as adjuvant therapy to mechanical debridement for the treatment of experimental periodontitis (EP).

MATERIAL AND METHODS

We used 120 male rats (Rattus norvegicus albinus - Wistar), divided into the following four groups: NEP (sham) (n = 30): no experimental periodontitis (NEP), only simulation of EP by installation and removal of a ligature; EP (n = 30): EP induction by ligature; SRP (n = 30): EP, scaling and root planing (SRP), and irrigation with physiological saline solution; SRP/GT (n = 30): EP, SRP, and irrigation with GTE. Histologic analysis and immunohistochemistry were performed for detection of interleukin (IL)1ß, tumor necrosis factor-alpha (TNF-α), IL-10, and anti-tartrate resistant acid phosphatase (TRAP) in the furcation area. The percentage of bone in the furcation (PBF) was considered the primary variable and evaluated at 14, 22, and 37 days. The data from the histological analysis and the IL- 1B, TNF- A, and IL-10 were submitted to a Kruskal-Wallis variance test and Dunn's posttest (p ≤ 0.05). The histometric data and TRAP were submitted to analysis of variance (ANOVA) and Tukey's posttest (p ≤ 0.05).

RESULTS

The SRP/GT group showed lower inflammatory process, lower immunolabeling pattern of IL-1ß and TNF-α, and greater immunolabeling pattern of IL-10 compared with the EP and SRP groups at 22 days. Fewer TRAP-positive multinucleated osteoclasts were observed in all periods in the SRP/GT group (5.22 ± 0.65; 7.33 ± 0.80; 8.55 ± 1.15) compared with the SRP group (30.67 ± 8.55; 13.22 ± 0.77; 13.87 ± 0.77). Higher PBF was observed in all periods in the SRP/GT group (74.65 ± 7.14; 76.61 ± 5.36; 79.24 ± 3.75) compared with the SRP group (61.60 ± 9.48; 54.84 ± 9.06; 53.25 ± 9.66).

CONCLUSION

GTE adjuvant to SRP reduced inflammation, osteoclastic activity, and alveolar bone loss in EP.

Novel Approaches to the Control of Oral Microbial Biofilms

Effective management of biofilm-related oral infectious diseases is a global challenge. Oral biofilm presents increased resistance to antimicrobial agents and elevated virulence compared with planktonic bacteria. Antimicrobial agents, such as chlorhexidine, have proven effective in the disruption/inhibition of oral biofilm. However, the challenge of precisely and continuously eliminating the specific pathogens without disturbing the microbial ecology still exists, which is a major factor in determining the virulence of a multispecies microbial consortium and the consequent development of oral infectious diseases. Therefore, several novel approaches are being developed to inhibit biofilm virulence without necessarily inducing microbial dysbiosis of the oral cavity. Nanoparticles, such as pH-responsive enzyme-mimic nanoparticles, have been developed to specifically target the acidic niches within the oral biofilm where tooth demineralization readily occurs, in effect controlling dental caries. Quaternary ammonium salts (QAS) such as dimethylaminododecyl methacrylate (DMADDM), when incorporated into dental adhesives or resin composite, have also shown excellent and durable antimicrobial activity and thus could effectively inhibit the occurrence of secondary caries. In addition, custom-designed small molecules, natural products and their derivatives, as well as basic amino acids such as arginine, have demonstrated ecological effects by modulating the virulence of the oral biofilm without universally killing the commensal bacteria, indicating a promising approach to the management of oral infectious diseases such as dental caries and periodontal diseases. This article aims to introduce these novel approaches that have shown potential in the control of oral biofilm. These methods may be utilized in the near future to effectively promote the clinical management of oral infectious diseases and thus benefit oral health.