Enamel matrix derivative in liquid form as adjunct to natural bovine bone grafting at buccal bone dehiscence defects at implant sites: An experimental study in beagle dogs

OBJECTIVES

To evaluate the effect of enamel matrix derivative in liquid form (EMD-liquid) as adjunct to grafting with natural bovine bone (NBB), on new bone formation and osseointegration in buccal dehiscence defects at dental implants.

MATERIAL AND METHODS

In six beagles, 3 months after extraction of the mandibular premolars and first molars. Three titanium implants (3.3 Ø × 8.0 mm) were inserted, and dehiscence-type defects (mesiodistal width 3 mm × 5 mm depth) were created on their buccal aspect. The defects were randomly assigned to one of the following three treatment groups: Group 1: NBB, Group 2: NBB/EMD-L, Group 3: Control. All sites were covered with a collagen membrane. Histomorphometric measurements were performed after 3 months of healing.

RESULTS

New bone area, bone-to-implant contact (BIC), and first BIC (fBIC) in the NBB and NBB/EMD-L groups were significantly greater than in the control group (p < .05). Further, f-BIC was at a significantly more coronal position in the NBB + EMD-liquid group (0.4 ± 0.1 mm) compared with the NBB group (1.2 ± 0.2 mm).

CONCLUSIONS

Natural bovine bone grafting enhances bone regeneration and osseointegration at implants with buccal bone dehiscences compared with no grafting, and adjunct use of EMD-liquid appears to further enhance bone formation and osseointegration.

Correlation of plasma osteopontin and osteocalcin with lower renal function in dental patients with carotid artery calcification and tooth loss

OBJECTIVES

To investigate plasma osteopontin (OPN) and osteocalcin (OCN) levels in dental patients with carotid artery calcification (CAC) and determine the correlations between these proteins and renal function and tooth loss.

METHODS

The health parameters and number of teeth of 99 participants were recorded. Panoramic radiographs were taken for CAC evaluation, and OPN and OCN levels were measured.

RESULTS

None of the participants had overt kidney disease, and 14 (14.14%) had CAC. The age, sex, and health profiles of patients with CAC were not different from those without CAC. The OPN and OCN levels in participants with CAC were higher than in those without (p = 0.026 and p = 0.025, respectively). The OPN levels were correlated with the estimated glomerular filtration rate (eGFR) (p = 0.021) and tooth loss (p = 0.027). The OCN levels were correlated with the eGFR (p = 0.002), tooth loss (p = 0.023), blood urea nitrogen (p = 0.040), and creatinine levels (p = 0.031). The median tooth loss in individuals with an eGFR <60 mL/min/1.73 m² was higher than that of individuals with an eGFR ≥60 mL/min/1.73 m² (p = 0.033). In individuals with CAC, tooth loss correlated more strongly with the eGFR, and the correlation between OPN and OCN levels was more apparent.

CONCLUSION

Dental patients with CAC and increased tooth loss have a greater tendency for decreased renal function, which may be associated with OPN and OCN; thus, these patients should be referred for investigation.

Increased Incidence of Cancer in Japanese Patients with Critical Limb Ischemia

Objective: This multicenter observational study was conducted in order to investigate the incidence of cancer in patients with critical limb ischemia. Materials and Methods: We prospectively investigated the incidence of cancer in 68 patients with critical limb ischemia over a two-year period. Patients underwent an intensive examination at enrollment, which included tumor marker levels and chest and abdominal computed tomography, as well as one- and two-year follow-up examinations. We compared the observed incidence of cancer with the expected incidence calculated from national cancer rates by the standardized incidence ratio (SIR). Results: The majority (83.6%) of the patients were men, and 92.5% of the patients had a peripheral arterial disease that was classified as Fontaine stage III or IV. During enrollment, newly diagnosed cancers were detected in seven patients. Four additional cancers were detected during the follow-up period. All of the detected cancers were asymptomatic. We observed an increased risk of cancer (SIR, 4.04; 95% confidence interval, 1.31-9.42) in patients with critical limb ischemia. Conclusion: This study suggests that critical limb ischemia is associated with an increased risk of cancer. Our findings should be taken into serious consideration by future investigators considering the use of therapeutic angiogenesis.

Ozone ultrafine bubble water induces the cellular signaling involved in oxidative stress responses in human periodontal ligament fibroblasts

Periodontitis is a chronic inflammatory disease caused by oral microorganisms in the subgingival biofilm. Stable aqueous ozone ultrafine bubble water (OUFBW) has recently begun to be used as an antiseptic in the treatment of periodontitis. The effectiveness of OUFBW is thought to depend on the bactericidal actions of dissolved ozone exerted via its oxidizing effect. On the other hand, the effects of ozone on the periodontal tissues are largely unknown. In this paper we examined the cellular responses after OUFBW treatment. Human primary periodontal ligament fibroblasts (hPDLFs) or Ca9-22 human gingival epithelial cells were treated with OUFBW or UV-inactivated OUFBW. The production of reactive oxygen species (ROS), the activation of mitogen-activated protein kinase (MAPK) and the nuclear factor-kappa B (NF-κB) activation were analyzed. The transcript profiles of hPDLFs after OUFBW treatment were also analyzed by RNA sequencing (RNA-seq). Our results showed that OUFBW induces oxidative stress by generating ROS, which, in turn, activated the MAPK pathway. OUFBW triggered activation of c-Fos, a major component of the transcription factor activator protein 1 (AP-1), and also nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2), which possessed a high sensitivity to oxidative stress. The results of RNA-seq analysis revealed that the numerous genes involved in oxidative stress responses or MAPK signaling pathway were up-regulated after OUFBW treatment. Investigation of the signaling pathways activated by OUFBW highlights another aspect of the biological roles of OUFBW, in addition to its bactericidal activity, in the treatment of periodontitis.

Salivary and serum cystatin SA levels in patients with type 2 diabetes mellitus or diabetic nephropathy

OBJECTIVE

To investigate putative salivary biomarkers for screening and diagnosis of type 2 diabetes mellitus and diabetic nephropathy.

DESIGN

Saliva and serum samples were collected from 29 patients with type 2 diabetes, 20 patients with diabetic nephropathy, eight patients with non-diabetic induced nephropathy, and 25 healthy subjects. Initially, pooled unstimulated saliva samples from six sex- and age-matched healthy subjects and six patients with type 2 diabetes were subjected to two-dimensional gel electrophoresis, followed by mass spectrometry. Protein expression of cystatin SA in the saliva of patients with type 2 diabetes was further examined in saliva and serum using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Two-dimensional gel electrophoresis revealed upregulation of salivary cystatin SA in patients with type 2 diabetes. ELISA showed a weak trend of increasing salivary cystatin SA levels in patients with type 2 diabetes, compared with those levels in healthy subjects. When patients were stratified according to periodontal status, linear regression analyses revealed that salivary cystatin SA levels were associated with Periodontal Screening and Recording (PSR) index (β = 0.297, p <  0.05) when the analysis was adjusted for age, sex, HbA_1C, estimated glomerular filtration rate (eGFR), and number of teeth. Serum cystatin SA levels were negatively associated with eGFR (β = -0.534, p <  0.0001) when the analysis was adjusted for age, sex, HbA_1C, number of teeth, and PSR index.

CONCLUSIONS

Salivary cystatin SA was associated with periodontal disease severity; moreover, serum cystatin SA levels could reflect kidney function.

The Effects of Ultraviolet Light-Emitting Diodes with Different Wavelengths on Periodontopathic Bacteria In Vitro

Objective: The aim of this study was to examine effects of recently developed ultraviolet light-emitting diodes (UV LEDs) wavelengths on in vitro growth and gene expression of cultural periodontopathic bacteria, and on viability of experimental gingival fibroblasts. Materials and methods: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Streptococcus oralis were irradiated by UV LEDs (265, 285, 310, 365, and 448 nm) at 600 mJ/cm² and grown anaerobically in vitro. The colony forming units were counted after 1 week. Cell morphology was observed using a scanning electron microscope (SEM). Quantitative real-time polymerase chain reaction was performed to investigate gene expression changes by 310 nm irradiation. Viability of the irradiated human gingival fibroblasts was evaluated using WST-8 assay. Results: Both 265 and 285 nm resulted in the complete death of bacteria and fibroblasts, whereas 310 nm caused partial killing and suppression of bacterial growth and much less damage to the fibroblasts in vitro. Both 365 and 448 nm resulted in no significant change. SEM showed that P. gingivalis cells gradually degraded from day 2 or 3 and were severely destructed on day 5 for 265, 285, and 310 nm. The 310 nm irradiation transiently suppressed the transcripts of SOS response- and cell division-relative genes. Conclusions: Both 265 and 285 nm may induce powerful bactericidal effects and severe fibroblast phototoxicity, and 310 nm may induce partial killing or growth suppression of bacterial cells with much less fibroblast phototoxicity. UV lights may have potential for bacterial suppression, with situations dependent on wavelength, in periodontal and peri-implant therapy.

Evaluation of bone healing following Er:YAG laser ablation in rat calvaria compared with bur drilling

The Er:YAG laser is currently used for bone ablation. However, the effect of Er:YAG laser irradiation on bone healing remains unclear. The aim of this study was to investigate bone healing following ablation by laser irradiation as compared with bur drilling. Rat calvarial bone was ablated using Er:YAG laser or bur with water coolant. Er:YAG laser effectively ablated bone without major thermal changes. In vivo micro-computed tomography analysis revealed that laser irradiation showed significantly higher bone repair ratios than bur drilling. Scanning electron microscope analysis showed more fibrin deposition on laser-ablated bone surfaces. Microarray analysis followed by gene set enrichment analysis revealed that IL6/JAK/STAT3 signaling and inflammatory response gene sets were enriched in bur-drilled bone at 6 hours, whereas the E2F targets gene set was enriched in laser-irradiated bone. Additionally, Hspa1a and Dmp1 expressions were increased and Sost expression was decreased in laser-irradiated bone compared with bur-drilled bone. In granulation tissue formed after laser ablation, Alpl and Gblap expressions increased compared to bur-drilled site. Immunohistochemistry showed that osteocalcin-positive area was increased in the laser-ablated site. These results suggest that Er:YAG laser might accelerate early new bone formation with advantageous surface changes and cellular responses for wound healing, compared with bur-drilling.

Influence of Porphyromonas gingivalis in gut microbiota of streptozotocin-induced diabetic mice

OBJECTIVES

Increasing evidence suggests that periodontitis can exacerbate diabetes, and gut bacterial dysbiosis appears to be linked with the diabetic condition. The present study examined the effects of oral administration of the periodontopathic bacterium, Porphyromonas gingivalis, on the gut microbiota and systemic conditions in streptozotocin-induced diabetic mice.

MATERIALS AND METHODS

Diabetes was induced by streptozotocin injection in C57BL/6J male mice (STZ). STZ and wild-type (WT) mice were orally administered P. gingivalis (STZPg, WTPg) or saline (STZco, WTco). Feces were collected, and the gut microbiome was examined by 16S rRNA gene sequencing. The expression of genes related to inflammation, epithelial tight junctions, and glucose/fatty acid metabolism in the ileum or liver were examined by quantitative PCR.

RESULTS

The relative abundance of several genera, including Brevibacterium, Corynebacterium, and Facklamia, was significantly increased in STZco mice compared to WTco mice. The relative abundances of Staphylococcus and Turicibacter in the gut microbiome were altered by oral administration of P. gingivalis in STZ mice. STZPg mice showed higher concentrations of fasting blood glucose and inflammatory genes levels in the ileum, compared to STZco mice.

CONCLUSIONS

Oral administration of P. gingivalis altered the gut microbiota and aggravated glycemic control in streptozotocin-induced diabetic mice.

Deep sequencing reveals specific bacterial signatures in the subgingival microbiota of healthy subjects

OBJECTIVES

This study aimed to define the comprehensive bacterial flora of the healthy oral cavity by identifying and comparing bacterial species in different subgingival sites using 454 sequencing of 16S rRNA genes.

MATERIALS AND METHODS

Subgingival plaque samples were taken from six target teeth (central incisor, first premolar, and first molar in both the maxilla and mandible) of 10 periodontally healthy patients. Bacterial DNA was extracted and next-generation sequencing of 16S rRNA genes was performed.

RESULTS

Bacterial composition in phylum level was similar for all sites within the same individual irrespective of tooth location. Unweighted UniFrac distance values of microbiome also showed that average distance was significantly larger between subjects than between tooth locations of the same subjects.

CONCLUSIONS

The present results clarify the lack of effect of tooth location in the healthy subgingival microbiota. Results may suggest that any subgingival site can demonstrate similar subject-specific microbiota.

CLINICAL RELEVANCE

This investigation offers a better understanding of the uniqueness of the oral microbiome. The present study will facilitate sampling in future subgingival microbiological studies.

Accelerated inflammation in peripheral artery disease patients with periodontitis

Purpose

Peripheral artery disease (PAD) is a form of arteriosclerosis that occurs in the extremities and involves ischemia. Previous studies have reported that patients with periodontitis are at high risk for PAD. However, the relationship between these 2 diseases has not yet been fully elucidated. In this cross-sectional study, we investigated this relationship by comparing patients with PAD to those with arrhythmia (ARR) as a control group.

Methods

A large-scale survey was conducted of patients with cardiovascular disease who visited Tokyo Medical and Dental University Hospital. We investigated their oral condition and dental clinical measurements, including probing pocket depth, bleeding on probing, clinical attachment level, and number of missing teeth; we also collected salivary and subgingival plaque samples and peripheral blood samples. All patients with PAD were extracted from the whole population (n=25), and a matching number of patients with ARR were extracted (n=25). Simultaneously, ARR patients were matched to PAD patients in terms of age, gender, prevalence of diabetes, hypertension, dyslipidemia, obesity, and the smoking rate (n=25 in both groups). Real-time polymerase chain reaction was performed to measure the bacterial counts, while the enzyme-linked immunosorbent assay method was used to measure anti-bacterial antibody titers and proinflammatory cytokine levels in serum.

Results

PAD patients had more missing teeth (18.4±2.0) and higher serum levels of C-reactive protein (1.57±0.85 mg/dL) and tumor necrosis factor-alpha (70.3±5.7 pg/mL) than ARR patients (12.0±1.7, 0.38±0.21 mg/dL, and 39.3±4.5 pg/mL, respectively). Meanwhile, no statistically significant differences were found in other dental clinical measurements, bacterial antibody titers, or bacterial counts between the 2 groups.

Conclusions

Our findings suggested that PAD patients had poorer oral and periodontal state with enhanced systemic inflammation.

A cross-sectional study on the periodontal status and prevalence of red complex periodontal pathogens in a Japanese population

This large-scale study cross-sectionally examined the periodontal status and prevalence of "red complex" bacteria (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) in Japanese adults. A total of 977 participants were enrolled in the study. Probing depth (PD), bleeding on probing (BOP), and bone crest level (BCL) were recorded, and the presence of red complex bacteria in the saliva was examined using polymerase chain reaction. The mean BCL value and the percentage of sites with a PD ≥4 mm or the presence of BOP were significantly higher in older participants. The detection rates of P. gingivalis, T. denticola, and T. forsythia were 46.3%, 76.4%, and 61.1%, respectively. The P. gingivalis detection rate significantly increased with age, while those of T. denticola and T. forsythia were comparably high for all age groups. A close correlation between P. gingivalis and the percentage of sites with PD ≥4 mm was indicated by nonlinear canonical correlation analysis. Current smokers exhibited a more advanced disease condition and a significantly higher P. gingivalis detection rate than non-smokers. In conclusion, periodontal condition worsens with age, and P. gingivalis appears to be the red complex bacterium most closely associated with periodontitis.

Periodontal regenerative effect of enamel matrix derivative in diabetes

The present study aimed to investigate the periodontal regenerative effect of enamel matrix derivative (EMD) in diabetes. Thirty-six rats were assigned to streptozotocin-induced diabetes or control (non-diabetic) groups. Three-wall intrabony defects were surgically generated in the bilateral maxilla molar, followed by application of EMD or saline. Primary wound closure and defect fill were evaluated via histomorphological analysis and micro-computed tomography. mRNA expression levels of inflammatory and angiogenic factors in the defects were quantified via real-time polymerase chain reaction. Gingival fibroblasts were isolated from control animals and cultured in high-glucose (HG) or control medium. The effects of EMD on insulin resistance and PI3K/Akt/VEGF signaling were evaluated. The achievement rate of primary closure and the parameters of defect fill were significantly higher at EMD-treated site than at EMD-untreated sites in both diabetic and non-diabetic rats, although defect fill in the diabetic groups was significantly lower in the control groups on two-way repeated-measures analysis of variance (for both, p<0.05). Newly formed bone and cementum were significantly increased at EMD-treated sites in diabetic rats than at EMD-untreated sites in control rats (for both, p<0.05). Vegf was significantly upregulated at EMD-treated sites in both diabetic and non-diabetic rats (for both, p<0.05). In vitro, insulin or EMD-induced Akt phosphorylation was significantly lower in cells cultured in HG medium (p<0.05). EMD-mediated Vegf upregulation was suppressed by the Akt inhibitor wortmannin, although the effect was significantly lower in HG medium (p<0.01). In conclusion, EMD might promote periodontal tissue regeneration via Akt/VEGF signaling, even in a diabetic condition.

High-energy, nanosecond pulsed Cr:CdSe laser with a 2.25-3.08 μm tuning range for laser biomaterial processing

We have developed a mid-infrared (mid-IR) tunable Cr:CdSe laser with nanosecond pulse operation. A broad tuning range from 2.25 to 3.08 µm and an output energy exceeding 4 mJ at 2.64 μm were demonstrated. The maximum energy conversion for absorbed energy reached 35% when the pump fluence was 2.1 J/cm². We showed that Cr:CdSe is an attractive laser material for obtaining high-energy pulses in the mid-IR region and that the Cr:CdSe laser has high potential for laser biomaterial processing.

Endotoxemia by Porphyromonas gingivalis Injection Aggravates Non-alcoholic Fatty Liver Disease, Disrupts Glucose/Lipid Metabolism, and Alters Gut Microbiota in Mice

Many risk factors related to the development of non-alcoholic fatty liver disease (NAFLD) have been proposed, including the most well-known of diabetes and obesity as well as periodontitis. As periodontal pathogenic bacteria produce endotoxins, periodontal treatment can result in endotoxemia. The aim of this study was to investigate the effects of intravenous, sonicated Porphyromonas gingivalis (Pg) injection on glucose/lipid metabolism, liver steatosis, and gut microbiota in mice. Endotoxemia was induced in C57BL/6J mice (8 weeks old) by intravenous injection of sonicated Pg; Pg was deactivated but its endotoxin remained. The mice were fed a high-fat diet and administered sonicated Pg (HFPg) or saline (HFco) injections for 12 weeks. Liver steatosis, glucose metabolism, and gene expression in the liver were evaluated. 16S rRNA gene sequencing with metagenome prediction was performed on the gut microbiota. Compared to HFco mice, HFPg mice exhibited impaired glucose tolerance and insulin resistance along with increased liver steatosis. Liver microarray analysis demonstrated that 1278 genes were differentially expressed between HFco and HFPg mice. Gene set enrichment analysis showed that fatty acid metabolism, hypoxia, and TNFα signaling via NFκB gene sets were enriched in HFPg mice. Although sonicated Pg did not directly reach the gut, it changed the gut microbiota and decreased bacterial diversity in HFPg mice. Metagenome prediction in the gut microbiota showed enriched citrate cycle and carbon fixation pathways in prokaryotes. Overall, intravenous injection of sonicated Pg caused impaired glucose tolerance, insulin resistance, and liver steatosis in mice fed high-fat diets. Thus, blood infusion of Pg contributes to NAFLD and alters the gut microbiota.

Countermeasures against Infection in Critical Limb Ischemia Treatments

The preoperative and postoperative infection control measures for critical limb ischemia treatments were described. The treatment strategies for severe ischemic limbs were showed according to the presence and extent of infection. If the treatment strategy for a severe ischemic limb with infection is mistaken, infection will spread and make worse the situation of the ischemic limb, and eventually it can result not only in limb loss but also life threatening. A surgical strategy is very important in the bypass material, the selection of anastomotic site, the use of postoperative antibacterial drugs, and the wound treatment. Infection troubles are the most familiar and indispensable problem for surgeons, the countermeasures against infection especially in critical limb ischemia is the key point along with revascularization. (This is a translation of Jpn J Vasc Surg 2018; 27: 129–132.)

Periodontal regeneration with autologous periodontal ligament-derived cell sheets - A safety and efficacy study in ten patients

Background

Periodontitis results in the destruction of tooth-supporting periodontal tissues and does not have the ability to heal spontaneously. Various approaches have been introduced to regenerate periodontal tissues; however, these approaches have limited efficacy for treating severe defects. Cytotherapies combine stem cell biology and tissue engineering to form a promising approach for overcoming these limitations. In this study, we isolated periodontal ligament (PDL)-derived cells from patients and created cell sheets with “Cell Sheet Engineering Technology”, using temperature responsive culture dishes, in which all the cultured cells can be harvested as an intact transplantable cell sheet by reducing the temperature of the culture dish. Subsequently, the safety and efficacy of autologous PDL-derived cell sheets were evaluated in a clinical setting.

Methods

A single-arm and single-institute clinical study was performed to verify the safety and efficacy of autologous PDL-derived cell sheets in patients with periodontitis. Wisdom teeth were extracted from patients diagnosed with chronic periodontitis, ranging in age from 33 to 63 years (mean [±SD], 46 ± 12), and periodontal tissues were scraped for cell sources. Three-layered PDL-derived cell sheets were constructed using temperature-responsive culture dishes and transplanted in an autologous fashion following standard flap surgeries. Bony defects were filled with beta-tricalcium phosphate granules. Clinical variables were evaluated at baseline, 3 months, and 6 months. Cone-beam computed tomography was performed at baseline and 6 months. Additionally, mid-long-term follow-up has been performed with patients’ agreements.

Results

Our method was found to be safe and no severe adverse events were identified. All the findings, including reduction of periodontal probing depth (mean ± SD, 3.2 ± 1.9 mm), clinical attachment gain (2.5 ± 2.6 mm), and increase of radiographic bone height (2.3 ± 1.8 mm), were improved in all 10 cases at 6 months after the transplantation. These therapeutic effects were sustained during a mean follow-up period of 55 ± 19 months, and there were no serious adverse events.

Conclusions

The results of this study validate the safety and efficacy of autologous PDL-derived cell sheets in severe periodontal defects, and the stability of this efficacy during mid-long-term follow up. This cytotherapeutic approach, based on cell sheet engineering, offers an innovative strategy to treat the recognized unmet need of treating severe periodontal defects.

High glucose-induced oxidative stress impairs proliferation and migration of human gingival fibroblasts

Delayed gingival wound healing is widely observed in periodontal patients with diabetes. However, the molecular mechanisms of the impaired function of gingival fibroblasts in diabetes remain unclear. The purpose of this study was to investigate changes in the properties of human gingival fibroblasts (HGFs) under high-glucose conditions. Primary HGFs were isolated from healthy gingiva and cultured with 5.5, 25, 50, and 75 mM glucose for 72 h. In vitro wound healing, 5-ethynyl-2′-deoxyuridine (EdU), and water-soluble tetrazolium salt (WST-8) assays were performed to examine cell migration and proliferation. Lactase dehydrogenase (LDH) levels were measured to determine cytotoxicity. The mRNA expression levels of oxidative stress markers were quantified by real-time PCR. Intracellular reactive oxygen species (ROS) were also measured in live cells. The antioxidant N-acetyl-l-cysteine (NAC, 1 mM) was added to evaluate the involvement of ROS in the glucose effect on HGFs. As a result, the in vitro wound healing assay showed that high glucose levels significantly reduced fibroblast migration and proliferation at 6, 12, 24, 36, and 48 h. The numbers of cells positive for EdU staining were decreased, as was cell viability, at 50 and 75 mM glucose. A significant increase in LDH was proportional to the glucose concentration. The mRNA levels of heme oxygenase-1 and superoxide dismutase-1 and ROS levels were significantly increased in HGFs after 72 h of exposure to 50 mM glucose concentration. The addition of NAC diminished the inhibitory effect of high glucose in the in vitro wound healing assay. The results of the present study show that high glucose impairs the proliferation and migration of HGFs. Fibroblast dysfunction may therefore be caused by high glucose-induced oxidative stress and may explain the delayed gingival wound healing in diabetic patients.