Female reproductive tract-organ axes.

The female reproductive tract (FRT) and remote/versatile organs in the body share bidirectional communication. In this review, we discuss the framework of the "FRT-organ axes." Each axis, namely, the vagina-gut axis, uterus-gut axis, ovary-gut axis, vagina-bladder axis, vagina-oral axis, uterus-oral axis, vagina-brain axis, uterus-brain axis, and vagina-joint axis, is comprehensively discussed separately. Each axis could be involved in the pathogenesis of not only gynecological diseases but also diseases occurring apart from the FRT. Although the microbiota is clearly a key player in the FRT-organ axes, more quantitative insight into the homeostasis of the microbiota could be provided by host function measurements rather than current microbe-centric approaches. Therefore, investigation of the FRT-organ axes would provide us with a multicentric approach, including immune, neural, endocrine, and metabolic aspects, for understanding the homeostatic mechanism of women's bodies. The framework of the FRT-organ axes could also provide insights into finding new therapeutic approaches to maintain women's health.

Identification of Nutritional Factors to Evaluate Periodontal Clinical Parameters in Patients with Systemic Diseases.

Nutritional factors reflect the periodontal parameters accompanying periodontal status. In this study, the associations between nutritional factors, blood biochemical items, and clinical parameters were examined in patients with systemic diseases. The study participants were 94 patients with heart disease, dyslipidemia, kidney disease, or diabetes mellitus. Weak negative correlation coefficients were found between nine clinical parameters and ten nutritional factors. Stage, grade, mean probing depth (PD), rate of PD 4−5 mm, rate of PD ≥ 6 mm, mean clinical attachment level (CAL), and the bleeding on probing (BOP) rate were weakly correlated with various nutritional factors. The clinical parameters with coefficients of determinations (R2) > 0.1 were grade, number of teeth, PD, rate of PD 4−5 mm, CAL, and BOP rate. PD was explained by yogurt and cabbage with statistically significant standardized partial regression coefficients (yogurt: −0.2143; cabbage and napa cabbage: −0.2724). The mean CAL was explained by pork, beef, mutton, and dark green vegetables with statistically significant standardized partial regression coefficients (−0.2237 for pork, beef, and mutton; −0.2667 for dark green vegetables). These results raise the possibility that the frequency of intake of various vegetables can be used to evaluate periodontal stabilization in patients with systemic diseases.

Association between Dietary Habit and Clinical Parameters in Patients with Chronic Periodontitis Undergoing Supportive Periodontal Therapy.

The recurrence risk evaluation has been emphasized in periodontal stabilization during supportive periodontal therapy (SPT). However, nutritional factors, e.g., dietary habits such as the frequency of eating vegetables, are rarely included in the evaluation. In this study, the effect of nutritional factors on clinical periodontal parameters was examined in a lifestyle-related investigation and a periodontal examination in patients with periodontitis undergoing SPT. A total of 106 patients were recruited. Tendencies toward a negative correlation were found between rate of a probing depth (PD) of 4-5 mm, rate of PD ≥ 6 mm, the bleeding on probing (BOP) rate, periodontal inflamed surface area (PISA), and various nutritional factors. The number of teeth was a clinical parameter with a significantly high R2 (≥0.10) influenced by environmental factors, whereas PD, PD of 4-5 mm, the BOP rate, and PISA were influenced by nutritional factors. These results suggested that environmental factors reflected clinical parameters showing long-term pathophysiology, such as the PD rate. Nutritional factors tended to affect the current inflammatory pathophysiology, such as the BOP rate, PISA, and PISA/periodontal epithelial surface area. Therefore, environmental and nutritional factors appear to be useful for evaluating the risk of periodontitis during SPT.

Lymphocyte antigen 6 complex locus G6D downregulation is a novel parameter for functional impairment of neutrophils in aged mice.

Immunological aging is a critical event that causes serious functional impairment in the innate immune system. However, the identification markers and parameters are still poorly understood in immunological aging of myeloid lineage cells. Here, we show that a downregulation of lymphocyte antigen 6 complex locus G6D (Ly-6G) observed in aged mouse neutrophils could serve as a novel marker for the prediction of age-associated functional impairment in the neutrophils. Ly-6G expression was significantly downregulated in the bone marrow (BM) neutrophils of aged mice compared to young mice confirmed by flow cytometry analysis. In vitro experiments using BM-isolated neutrophils showed significant downregulations in their activities, such as phagocytosis, reactive oxygen species (ROS) production, interleukin (IL)-1ß production, neutrophil extracellular trap (NET) formation, and migration as well as bacterial clearance, in the aged mouse neutrophils compared to those of young mice counterparts. Interestingly, the magnitudes of functional parameters were strongly correlated with the Ly-6G expression in the neutrophils. Thus, our results suggest that downregulation of Ly-6G reflects the age-associated functional attenuation of the neutrophils.

Sublingual immunization with recombinant GroEL plus CpG-ODN inhibits Porphyromonas gingivalis-induced inflammation and alveolar bone loss.

It has been reported that GroEL, a heat shock protein (HSP) produced by the representative periodontopathogenic bacterium, Porphyromonas gingivalis, induces inflammation-induced osteoclastogenesis and promotes alveolar bone resorption. In this study, we demonstrated the efficacy of a mucosal vaccine targeting GroEL against bone resorption induced by P. gingivalis. Female BALB/c mice received sublingual CpG oligodeoxynucleotide as an adjuvant with recombinant GroEL (rGroEL) prior to P. gingivalis exposure. Animals were euthanized 30 days after P. gingivalis inoculation. Sublingual immunization (SLI) with rGroEL elicited significant rGroEL-specific serum immunoglobulin (Ig)G and salivary IgA antibody (Ab) responses, and these responses were sustained for approximately 1 year. Interestingly, 10-fold more GroEL-specific IgA Ab-producing cells were detected in the submandibular glands (SMGs) than in the spleen. Antigen (Ag)-specific cells isolated from the spleen and SMGs induced significantly higher levels of IFN-γ expression after Ag restimulation in vitro. Flow cytometry illustrated that the frequency of CD11b+ dendritic cells with enhanced expression of CD80, CD86, CD40, and major histocompatibility complex II molecules was significantly increased in the SMGs. Furthermore, SLI with rGroEL significantly suppressed P. gingivalis-induced alveolar bone resorption and P. gingivalis-stimulated tumor necrosis factor-α, interleukin-6, and HSP60 expression in the gingiva. These findings suggest that SLI with rGroEL and CpG oligodeoxynucleotide is a beneficial strategy for preventing periodontal disease, mainly by presenting Ags in the oral region and inducing antibody production in the mucosal and systemic systems.

Lactic acid bacteria prevent both periodontitis and atherosclerosis exacerbated by periodontitis in spontaneously hyperlipidemic mice.

BACKGROUND AND OBJECTIVE: Recent studies have shown a link between periodontal disease and cardiovascular disease. We have previously reported that oral administration of Porphyromonas gingivalis (Pg) accelerates atherosclerosis in apolipoprotein E-deficient spontaneously hyperlipidemic (Apoeshl ) mice. This study evaluated the potential of lactic acid bacteria (LAB) to change the intestinal flora changes induced by periodontopathic bacteria and to prevent/slow down the development of atherosclerosis. METHODS: Lactobacillus gasseri O3-2 (Lg) was orally intubated in Apoeshl mice for 5 weeks. Three weeks after oral intubation, the mice were orally infected with Pg for 2 weeks. RESULTS: Thirty days after the last infection with Pg, Lg+Pg-treated mice showed a significant reduction in alveolar bone loss compared to the Pg-treated group. The Lg treatment restored the Pg-induced intestinal flora disturbance to normal. Furthermore, a significant decrease in atherosclerotic plaque lesion size and suppressed inflammatory cytokine production in the aorta were detected in the Lg + Pg-treated group. In contrast, blood concentrations of TMAO, histidine, and carnitine were enhanced by the Lg treatment but decreased by Lg + Pg treatment. CONCLUSION: These results suggest that oral Lg treatment is effective in preventing periodontitis and atherosclerosis.

Impaired salivary SIgA antibodies elicit oral dysbiosis and subsequent induction of alveolar bone loss.

OBJECTIVE: Secreted IgA (SIgA) plays a central role in preventing bacterial and viral infections on mucosal surfaces by neutralizing toxins and viruses and inhibiting bacterial attachment to epithelial cells. However, the role of salivary SIgA antibodies (Abs) in regulating oral flora is still unknown. This study aimed to evaluate the association among oral bacteria, their metabolites and periodontitis in IgA-deficient (IgA KO) and wild-type (WT) control mice. METHODS: Microcomputed tomography (micro-CT) analysis was used to assess alveolar bone resorption as a development of periodontitis. The bacterial profiles of saliva were determined using the next-generation sequencing assays. Furthermore, the metabolites in saliva were measured and compared using CE-TOFMS. RESULTS: Salivary microbiota of IgA KO mice revealed a remarkably decreased frequency of Streptococcus, and increased percentages of Aggregatibacer, Actinobacillus, and Prevotella at the genus level when compared with those of WT. Compared to WT control mice of the same age, the level of alveolar bone loss was significantly increased in IgA KO mice, and infiltration of osteoclasts was found on the surface of the alveolar bone. The metabolome profile indicated that the metabolites of IgA KO mice had greater variability in carbon metabolic, urea cycle, and lipid pathways than WT mice. CONCLUSION: These results suggest that salivary SIgA plays an important role in regulating and maintaining normal oral microflora to prevent the development of periodontal disease.

Oral bacteria affect the gut microbiome and intestinal immunity.

Recently, it has been suggested that the oral administration of Porphyromonas gingivalis, a keystone pathogen for periodontal disease, induces dysbiosis of the mouse intestinal microbiota and affects intestinal barrier function. Since oral streptococci are the predominant oral bacterial group, we compared the effect of their oral administration on the intestinal tract compared to that of P. gingivalis. Swallowing oral bacteria caused gut dysbiosis, due to increased Bacteroides and Staphylococcus and decreased Lactobacillus spp. Furthermore, oral bacterial infection caused an increase in lactate and decreases in succinate and n-butyrate contents. In the small intestine, the decrease in Th17 cells was considered to be a result of oral bacterial infection, although the population of Treg cells remained unaffected. In addition, oral bacterial challenge increased the M1/M2 macrophage ratio and decreased the immunoglobulin A (IgA) antibody titer in feces. These results suggest that gut dysbiosis caused by oral bacteria may cause a decrease in Th17 cells and fecal IgA levels and an increase in the M1/M2 macrophage ratio, thereby promoting chronic inflammation.

Oral challenge with Streptococcus sanguinis induces aortic inflammation and accelerates atherosclerosis in spontaneously hyperlipidemic mice.

Atherosclerosis is exacerbated by periodontal pathogens, which induce vascular inflammation after entering the bloodstream. Among oral indigenous bacteria, Streptococcus sanguinis and S. anginosus are related to systemic disorders, such as infective endocarditis and abscess, and are sometimes detected in human atherosclerotic plaques or blood. Thus, these oral streptococci may contribute to the progression of atherosclerosis. To test this hypothesis, apolipoprotein E-deficient spontaneously hyperlipidemic mice were intraorally challenged with S. sanguinis or S. anginosus. Atherosclerotic plaque formation increased significantly in the S. sanguinis-challenged group compared with the carboxymethylcellulose-treated control group. Expression levels of mRNAs of proinflammatory cytokines in the aorta and levels of atherosclerosis-related mediators in blood increased upon S. sanguinis challenge. Adaptor molecule TNF receptor-associated factor 6 was also enhanced in the aorta when mice were challenged with S. sanguinis. Furthermore, challenge with S. anginosus induced systemic inflammation, but inflammation-related mRNA expression levels in the aorta only increased slightly and were accompanied by minimal expansion of the lesion area. By contrast, with the exception of IL-1α, the expression levels of inflammation-related genes did not change in gingival tissues of both bacteria- and sham-challenged groups. These results reveal that S. sanguinis causes aortic inflammation that leads to accelerated progression of atherosclerosis.

Lactobacillus helveticus SBT2171 upregulates the expression of ß-defensin and ameliorates periodontal disease caused by Porphyromonas gingivalis.

Antimicrobial peptides play important roles in the innate immune system of various organisms, and they may also be considered to prevent the organisms from infections. In particular, ß-defensins, mainly produced in epithelial cells, are recognized as one of the major antimicrobial peptides in mammals, including humans. In this study, we showed that Lactobacillus helveticus SBT2171 (LH2171), one of the several species of lactic acid bacteria, upregulates the production of ß-defensins in oral epithelial cells in vitro. Moreover, LH2171 reduced the increase of proinflammatory cytokine expression, induced by Porphyromonas gingivalis stimulation, in gingival epithelial cells. These data suggested that LH2171 suppresses P. gingivalis-induced inflammation by upregulating the expression of ß-defensins in gingival epithelial cells. We subsequently investigated the effects of LH2171 in vivo and revealed that ß-defensin expression was increased in the oral cavities of LH2171-fed mice. Furthermore, LH2171 decreased alveolar bone loss, gingival inflammation, and amounts of P. gingivalis-specific 16S ribosomal RNA in the gingiva of P. gingivalis-inoculated mice. Taken together, our results showed that LH2171 upregulates the expression of ß-defensins in oral cavity, thereby decreasing the number of P. gingivalis consequently ameliorating the experimental periodontal disease.

CCR7-deficient mice exhibit a delayed antigen-specific mucosal IgA antibody response to an oral recombinant Salmonella strain.

The migration of antigen (Ag)-loading dendritic cells (DCs) from Peyer's patches (PPs) to the draining mesenteric lymph nodes (MLNs) via chemokine receptor 7 (CCR7) is thought to be an important step in the initiation of acquired immunity. Our previous study showed that PPs were indispensable for Ag-specific secretory (S)IgA antibody (Ab) responses against oral recombinant Salmonella (rSalmonella). In this study, we attempted to show direct PP DC migration to MLNs by employing photoconvertible protein transgenic mice and investigated the role of the CCR7 signaling pathway in mucosal IgA induction. Our results demonstrated an actual flux of DCs from PPs to MLNs. The frequency of CCR7+ CD11c+ DCs in MLNs of PP-deficient mice was reduced, suggesting that some PP DCs migrated via CCR7. Immunization of CCR7-/- mice elicited significantly lower levels of Ag-specific SIgA Ab responses, which was associated with diminished formation of the germinal center in PPs. However, increased SIgA Ab production and dissemination of rSalmonella were observed at later time points. These results suggest that, although CCR7 was required for SIgA induction at normal velocity, the CCR7-mediated pathway is not essential for the induction of Ag-specific SIgA Ab responses to rSalmonella.

C/EBPß and YY1 bind and interact with Smad3 to modulate lipopolysaccharide-induced amelotin gene transcription in mouse gingival epithelial cells.

Junctional epithelium (JE) develops from reduced enamel epithelium during tooth formation and is critical for the maintenance of healthy periodontal tissue through ensuring appropriate immune responses and the rapid turnover of gingival epithelial cells. We have previously shown a relationship between inflammatory cytokines and expression of JE-specific genes, such as amelotin (AMTN), in gingival epithelial cells. Here, we elucidated the effects of Porphyromonas gingivalis-derived lipopolysaccharide (Pg LPS) on Amtn gene transcription and the interaction of transcription factors. To determine the molecular basis of transcriptional regulation of the Amtn gene by Pg LPS, we performed real-time PCR and carried out luciferase assays using a mouse Amtn gene promoter linked to a luciferase reporter gene in mouse gingival epithelial GE1 cells. Gel mobility shift and chromatin immunoprecipitation assays were performed to identify response elements bound to LPS-induced transcription factors. Next, we analyzed protein levels of the LPS-induced transcription factors and the interaction of transcription factors by western blotting and immunoprecipitation. LPS increased Amtn mRNA levels and elevated luciferase activities of constructs containing regions between -116 and -238 of the mouse Amtn gene promoter. CCAAT/enhancer-binding protein (C/EBP) 1-, C/EBP2- and Ying Yang 1 (YY1)-nuclear protein complexes were increased by LPS treatment. Furthermore, we identified LPS-modulated interactions with C/EBPß, YY1 and Smad3. These results demonstrate that Pg LPS regulates Amtn gene transcription via binding of C/EBPß-Smad3 and YY1-Smad3 complexes to C/EBP1, C/EBP2 and YY1 response elements in the mouse Amtn gene promoter.

Pseudopropionibacterium rubrum sp. nov., a novel red-pigmented species isolated from human gingival sulcus.

In this study, Strain [corrected] SK-1(T), a novel gram-positive, pleomorphic, rod-shaped, non-spore forming, non-motile organism, designated SK-1T , was isolated from human gingival sulcus and found to produce acetic acid, propionic acid, lactic acid, and succinic acid as end products of glucose fermentation. Strain SK-1T is most closely related to Pseudopropionibacterium (Propionibacterium) propionicum with sequence homologies of the 16S rRNA and RNA polymerase ß subunit (rpoB) genes of 96.6% and 93.1%, respectively. The genomic DNA G + C content of the isolate was 61.8 mol%. On the basis of the sequence data of the 16S rRNA and housekeeping (rpoB) genes, a novel taxon is here proposed, Pseudopropionibacterium rubrum sp. nov. (type strain SK-1T = JCM 31317T = DSM 100122T ). The 16S rRNA and rpoB gene sequences of strain SK-1T have been deposited in the DDBJ under the accession numbers LC002971 and LC102236, respectively.

Regulation of the NLRP3 inflammasome in Porphyromonas gingivalis-accelerated periodontal disease.

OBJECTIVE: Porphyromonas gingivalis is involved in the pathogenesis of chronic inflammatory periodontal disease. Recent studies have suggested that the NLRP3 inflammasome plays an important role in the development of chronic inflammation. We investigated a possible association between the inflammasome in gingival inflammation and bone loss induced by P. gingivalis infection using NLRP3-deficient mice. METHODS: Wild-type and NLRP3-deficient mice were injected orally with P. gingivalis. We assessed alveolar bone loss, expression of pro-interleukin (IL)-1ß, pro-IL-18, receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) in gingival tissue, as well as IL-1ß, IL-18, and IL-6 production and caspase-1 activity in peritoneal macrophages. RESULTS: Porphyromonas gingivalis challenge significantly increased alveolar bone loss; gingival gene expression of pro-IL-1ß, pro-IL-18, and RANKL; production of IL-1ß, IL-18, and IL-6; and caspase-1 activity in peritoneal macrophages of wild-type mice, but did not affect NLRP3-deficient mice. Meanwhile, OPG mRNA expression in gingival tissue and peritoneal IL-6 production were significantly higher in NLRP3-knockout mice. CONCLUSIONS: Porphyromonas gingivalis activated innate immune cells via the NLRP3 inflammasome. These results suggest that the NLRP3 inflammasome, followed by a response from the IL-1 family, is critical in periodontal disease induced by wild-type P. gingivalis challenge via sustained inflammation.

Localization and expression pattern of amelotin, odontogenic ameloblast-associated protein and follicular dendritic cell-secreted protein in the junctional epithelium of inflamed gingiva.

The purpose of this study is to elucidate the localization of amelotin (AMTN), odontogenic ameloblast-associated protein (ODAM) and follicular dendritic cell-secreted protein (FDC-SP) at the junctional epithelium (JE) in Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans infected mice and inflamed and non-inflamed human gingiva. We performed immunostaining to determine the localization and expression pattern of AMTN, ODAM and FDC-SP. AMTN, ODAM and FDC-SP in A. actinomycetemcomitans infected mice did not change dramatically compared with non-infected mice. AMTN and FDC-SP expressions were observed stronger in P. gingivalis infected mice at early stage. However, at the following stage, the coronal part of the AMTN expression disappeared from the JE, and FDC-SP expression decreased due to severe inflammation by P. gingivalis. ODAM expressed internal and external basal lamina, and the expression increased not only at early stage but also at the following stage in the inflammatory JE induced by P. gingivalis. In the human gingival tissues, AMTN was detected at the surface of the sulcular epithelium and JE in the non-inflamed and inflamed gingiva, and the localization did not change the process of inflammation. ODAM and FDC-SP were more widely detected at the sulcular epithelium and JE in the non-inflamed gingiva. In the inflamed gingiva, localization of ODAM and FDC-SP was spread into the gingival epithelium, compared to AMTN. These studies demonstrated that the expression pattern of AMTN, ODAM and FDC-SP at the JE were changed during inflammation process and these three proteins might play an important role in the resistance to inflammation.

Activation of the NLRP3 inflammasome in Porphyromonas gingivalis-accelerated atherosclerosis.

Porphyromonas gingivalis has been shown to accelerate atherosclerotic lesion development in hyperlipidemic animals. Atherosclerosis is a disease characterized by inflammation of the arterial wall. Recent studies have suggested that the NLRP3 inflammasome plays an important role in the development of vascular inflammation and atherosclerosis. Herein, we investigated a possible association between the inflammasome in atherosclerosis and periodontal disease induced by P. gingivalis infection using apolipoprotein E-deficient, spontaneously hyperlipidemic (Apoe(shl)) mice. Oral infection with wild-type (WT) P. gingivalis significantly increased the area of aortic sinus covered with atherosclerotic plaque and alveolar bone loss, compared with KDP136 (gingipain-null mutant) or KDP150 (FimA-deficient mutant) challenge. WT challenge also increased IL-1ß, IL-18 and TNF-α production in peritoneal macrophages, and gingival or aortic gene expression of Nod-like receptor family, pyrin domain containing 3 (NLRP3), pro-IL-1ß, pro-IL-18 and pro-caspase-1. Porphyromonas gingivalis genomic DNA was detected more in the aorta, gingival tissue, liver and spleen of WT-challenged mice than those in KDP136- or KDP150-challenged mice. We conclude that WT P. gingivalis activates innate immune cells through the NLRP3 inflammasome compared with KDP136 or KDP150. The NLRP3 inflammasome may play a critical role in periodontal disease and atherosclerosis induced by P. gingivalis challenge through sustained inflammation.

Porphyromonas gingivalis infection enhances Th17 responses for development of atherosclerosis.

OBJECTIVES: Porphyromonas gingivalis has been shown to associate with the development of atherosclerosis. Recent studies indicate that IL-17-producing T helper 17 (Th17) cells have been correlated with the emergence of atherosclerosis. Therefore, we investigated whether the Th17 cell response and expression of Th17-related molecules, in contrast with Th1- and Treg cells, are enhanced by P. gingivalis-challenge in Apolipoprotein E knockout (ApoE KO) mice. DESIGN: Five mice were intravenously injected with P. gingivalis three times a week for 3 weeks and killed at 15 weeks of age. The proximal aorta lesion area, flow cytometry analysis and IL-17, IL-10, IFN-γ, and IL-1ß levels in splenic cultures, and expression of Th17-related molecules in spleen and hearts were examined. RESULTS: P. gingivalis-challenge showed notable accumulation of atherosclerotic plaques by Oil Red O-staining in ApoE KO mice. Intracellular cytokine staining revealed that significantly elevated CD4(+) interleukin (IL)-17A(+) T cells and slightly increased CD4(+) Foxp3(+) T cells was recognized in spleen cells of P. gingivalis-challenged mice compared with those from non-infected mice. P. gingivalis-challenge significantly increased IL-17 and IL-1ß production and RORγt expression in splenic cells. Furthermore, the expression of Th17-related genes such as IL-6, TGF-ß, RORγt and STAT3 were elevated in splenic cells as well as heart tissue of P. gingivalis-challenged mice. CONCLUSION: These results suggest that P. gingivalis infection may enhance pro-inflammatory Th17 cell responses in lesion areas and spleen, thereby accelerating atherosclerosis.

Midazolam inhibits IgE production in mice via suppression of class switch recombination.

Anaphylactic shock is characterized by increased capillary permeability and a decline in blood pressure due to excessive production of IgE. Midazolam (MDZ) is reported to have immunomodulatory properties. However, little is known about the effect of MDZ on the production of IgE antibody. We examined whether MDZ can suppress antigen-specific and total IgE production followed by IgE class switch recombination (CSR). MDZ was administered intraperitoneally to mice prior to ovalbumin (OVA) plus native cholera toxin (nCT) immunization. Serum OVA-specific and total IgE responses, and surface IgE-positive B cells were analyzed by ELISA and flow cytometry. Furthermore, expression levels of CSR-associated molecules such as germ-line transcript ε (εGLT), germ-circle tanscript ε (εCT), AID, and Id2 in the spleen were compared. The levels of interferon-gamma (IFN-γ) and interleukin (IL)-4 mRNA and protein were also examined in the spleen and serum. MDZ significantly suppressed OVA-specific and total IgE levels in plasma and surface IgE-positive B cells in the spleen. Moreover, MDZ-treated mice had significantly reduced levels of εGLT and εCT. Furthermore, although the levels of IFN-γ mRNA and protein were significantly elevated, those of IL-4 were reduced in MDZ-treated mice. Therefore, MDZ may be an important modulator of allergic responses through its ability to downregulate IgE production.

Nasal immunization with the 40-kDa outer membrane protein of Porphyromonas gingivalis plus cholera toxin induces protective immunity in aged mice.

Previous studies have demonstrated that nasal administration of the outer membrane protein of Porphyromonas gingivalis (40k-OMP) with cholera toxin (CT) as an adjuvant elicits protective immune responses against P. gingivalis in young mice. In the present study, we investigated whether administration of 40k-OMP plus CT would also induce 40k-OMP-specific antibody (Ab) responses to provide protective immunity against P. gingivalis infection in aged mice. Nasal immunization with 40k-OMP plus CT elicited 40k-OMP-specific IgG and IgA Ab responses in serum and a significant anti-40k-OMP IgA Ab response in nasal washes and saliva in 1- and 2-year-old mice. Furthermore, both Th1- and Th2-type cytokine responses were induced by the immunization, and cytokine-associated IgG1, IgG2a, and IgG2b Ab responses were observed in the spleens of aged mice. Although the aged mice showed lower 40k-OMP-specific Ab responses than young mice, their mucosal IgA Ab titers as well as serum IgG Ab responses indicated a retained ability to mediate protective immunity; the only exception was saliva in 2-year-old mice. These findings suggest that nasal immunization with 40k-OMP plus CT can be a potential vaccination strategy for eliciting levels of Abs sufficient to provide protective immunity against P. gingivalis infection in aged mice.

Porphyromonas gingivalis accelerates atherosclerosis in C57BL/6 mice fed a high-fat diet.

OBJECTIVE: Porphyromonas gingivalis has been shown to accelerate atherosclerotic lesion development in atherosclerotic apo E-deficient mice. Here, we investigated whether repeated P. gingivalis injection affected the inflammatory and atherosclerotic responses of C57BL/6 mice fed a high-fat diet (HFD). MATERIALS AND METHODS: Eight-week-old C57BL/6 mice fed either HFD or a regular chow diet (RD) were inoculated intravenously with P. gingivalis or phosphate-buffered saline three times per week for 10 weeks and sacrificed at 19 weeks of age. Atheromatous lesions in the proximal aorta of each animal were analyzed histomorphometrically, and the serum cytokine and C-reactive protein (CRP) levels were determined. RESULTS: Long-term HFD feeding as compared to RD feeding led to a slight increase in atheromatous lesions in the aortic sinus as well as increases in the levels of serum monocyte chemoattractant protein 1. Further, P. gingivalis injection significantly enhanced the formation of atherosclerotic plaque, and increased CRP and inflammatory cytokine levels, in mice fed the HFD, although no further increase in LDL was observed. CONCLUSION: These results suggest that bacteremia-induced by repeated injection with P. gingivalis accelerates atherosclerosis in normal C57BL/6 mice by initiating inflammation, and is therefore implicated in chronic infection-related pathogenicity.