Oral health and ventilator-associated pneumonia among critically ill patients: a prospective study.

OBJECTIVE: To evaluate the association between oral health and ventilator-associated pneumonia (VAP) among critically ill patients. METHODS: A prospective cohort study was conducted among 162 critically ill patients newly intubated and treated with mechanical ventilator in one tertiary hospital in Thailand. Oral health status was assessed using Oral Health Assessment Tool (OHAT), Plaque Index (PI), and number of teeth. VAP, defined as Clinical Pulmonary Infection Score >6, was assessed on Day 4 after intubation. Hazard ratios and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression adjusted for confounders. RESULTS: Critically ill patients had deteriorating oral health status after intubation. Early-onset VAP developed in 69 patients (42.6%), with VAP incidence of 117 episodes per 1000 ventilator-days. Moderately unhealthy and unhealthy oral conditions based on OHAT scores were associated with a 2.92-fold (95% CI: 1.26-6.74) and 3.22-fold (95% CI: 1.34-7.76) increased risk of VAP. Patients with moderate-to-very poor oral hygiene assessed by PI had increased VAP risk of 1.66-folds (95% CI: 1.001-2.75). The number of teeth was not associated with VAP development. CONCLUSIONS: There is a strong association between poor oral health and increased risk for early-onset VAP. Routine oral care possibly prevents VAP development among critically ill patients treated with mechanical ventilator.

Regulatory roles of beta-catenin and AP-1 on osteoprotegerin production in interleukin-1alpha-stimulated periodontal ligament cells.

BACKGROUND: Periodontitis is a chronic inflammatory disease characterized by the enhanced expression of inflammatory mediators leading to alveolar bone resorption. Osteoprotegerin (OPG) plays a suppressive role in cytokine-induced osteoclastogenesis. In osteoblasts, OPG expression is upregulated by beta-catenin but downregulated by the transcription factor activator protein-1 (AP-1; c-fos/c-jun). The purpose of this study was to examine the roles of beta-catenin and AP-1 in interleukin-1alpha (IL-1alpha) -induced OPG production in human gingival fibroblasts (hGFs) and periodontal ligament (PDL) cells. METHODS: Expression of c-fos and c-jun messenger RNA was measured by reverse transcription-polymerase chain reaction and OPG production was analysed by enzyme-linked immunosorbent assay. The nuclear AP-1 activity was quantified using an AP-1 microplate assay. The effect of the Wnt canonical pathway on OPG production was evaluated using small interfering (si) RNA for beta-catenin and the effect of AP-1 on OPG production was evaluated using the AP-1 inhibitor curcumin. RESULTS: Levels of c-fos messenger RNA and nuclear AP-1 activity were higher in PDL cells than in hGFs. When stimulated with IL-1alpha, PDL cells had significantly higher c-fos expression and lower OPG production compared with hGFs. The siRNA for beta-catenin suppressed the IL-1alpha-induced OPG production in both PDL cells and hGFs, whereas the AP-1 inhibitor curcumin augmented the IL-1alpha-induced OPG production in PDL cells, but not in hGFs. CONCLUSION: The present study suggests that beta-catenin enhances IL-1alpha-induced OPG production in both PDL cells and hGFs, whereas AP-1 suppresses IL-1alpha-induced OPG production in PDL cells. Higher expression of c-fos in PDL cells than in hGFs may implicate a role of PDL cells in alveolar bone resorption in periodontitis.

Red bacterial complex is associated with the severity of chronic periodontitis in a Thai population.

BACKGROUND: The distribution of periodontal pathogens differs in various geographic locations and racial/ethnic groups. This study investigated the microbiological features of chronic periodontitis (CP) patients in Thailand. METHODS: Subgingival plaque samples from 20 non-periodontitis subjects, 20 patients with mild CP, and 20 patients with moderate to severe CP were examined using polymerase chain reaction (PCR) to identify Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Aggregatibacter actinomycetemcomitans. RESULTS: In the moderate to severe CP patients, there was high prevalence of P. gingivalis (95%), T. forsythia (95%), T. denticola (80%), as well as the red complex (coexistence of all three species at the same lesion) (75%). A. actinomycetemcomitans was detected in only 35% of the patients in this study group. P. gingivalis was detected in as high as 45% of the non-periodontitis controls. CP and disease severity were significantly related to the presence of T. forsythia together with T. denticola and the red complex. The red complex was not found in any non-periodontitis site. CONCLUSION: Red complex bacteria were predominant periodontal pathogens of the moderate to severe form of CP in this Thai population. The presence of T. forsythia together with T. denticola, and the red complex species at the same site were significantly associated with the disease severity.

Cytomegalovirus IE2 protein stimulates interleukin 1beta gene transcription via tethering to Spi-1/PU.1.

Potent induction of the gene coding for human prointerleukin 1beta (il1b) normally requires a far-upstream inducible enhancer in addition to a minimal promoter located between positions -131 and +12. The transcription factor Spi-1 (also called PU.1) is necessary for expression and binds to the minimal promoter, thus providing an essential transcription activation domain (TAD). In contrast, infection by human cytomegalovirus (HCMV) can strongly activate il1b via the expression of immediate early (IE) viral proteins and eliminates the requirement for the upstream enhancer. Spi-1 has been circumstantially implicated as a host factor in this process. We report here the molecular basis for the direct involvement of Spi-1 in HCMV activation of il1b. Transfection of Spi-1-deficient HeLa cells demonstrated both the requirement of Spi-1 for IE activity and the need for a shorter promoter (-59 to +12) than that required in the absence of IE proteins. Furthermore, in contrast to normal, enhancer-dependent il1b expression, which absolutely requires both the Spi-1 winged helix-turn-helix (wHTH) DNA-binding domain and the majority of the Spi-1 TAD, il1b expression in the presence of IE proteins does not require the Spi-1 TAD, which plays a synergistic role. In addition, we demonstrate that a single IE protein, IE2, is critical for the induction of il1b. Protein-protein interaction experiments revealed that the wing motif within the Spi-1 wHTH domain directly recruits IE2. In turn, IE2 physically associates with the Spi-1 wing and requires the integrity of at least one region of IE2. Functional analysis demonstrates that both this region and a carboxy-terminal acidic TAD are required for IE2 function. Therefore, we propose a protein-tethered transactivation mechanism in which the il1b promoter-bound Spi-1 wHTH tethers IE2, which provides a TAD, resulting in the transactivation of il1b.

Clinical and microbiological effects of subgingival irrigation with Streblus asper leaf extract in chronic periodontitis.

OBJECTIVE: To determine the clinical and microbiological effects of subgingival irrigation of Streblus asper leaf extract (SAE) solution as an adjunct to scaling and root planing (SRP) in chronic periodontitis patients. METHODOLOGY: Forty-two subjects were included and treated with SRP at baseline (week 0), followed by subgingival irrigation with saline (control group, n=21) or SAE (test group, n=21) solution (80 mg/ml) at weeks zero, one, two, three, and four. Clinical parameters, including gingival index (GI), plaque index (PI), probing depth (PD), and relative attachment level (RAL) were measured at weeks zero, six, and 12. Microbiological parameters were measured at weeks zero, one, two, three, four, six, and 12. RESULTS: The SAE solution significantly reduced the GI compared with saline solution (p < 0.01). However, a reduction in PI, PD, and RAL was noted for both groups, with no statistically significant intergroup differences. The reduction in the number ofA. actinomycetemcomitans and/or P. gingivalis was maintained throughout the study period after subgingival irrigation with SAE solution, while an initial reduction and subsequent rebound were observed after saline irrigation. However, the mean number and mean percentages of sites with 10 times the reduction in number of these bacteria were not significantly different between the two groups. CONCLUSION: Subgingival irrigation with SAE solution as an adjunct to SRP is effective at reducing gingival inflammation, but not PD, RAL, and the number of A. actinomycetemcomitans and/or P. gingivalis.

Interleukin 1 signal transduction--current concepts and relevance to periodontitis.

This review examines a well-characterized factor, interleukin 1 (IL-1), that has recently received considerable attention. A level of understanding is emerging that goes beyond simple recognition that IL-1 plays a role in disease, and begins to explain the molecular mechanisms of function. This review summarizes some current information on the importance of IL-1 in periodontitis as well as the signal transduction of IL-1, from binding to its cell-surface receptors, to the activation of cytoplasmic mediators and transcription factors responsible for the induction of target genes. The effect of IL-1 signal transduction is ultimately the activation and repression of specific transcription factors that regulate genes responsible for cellular activities. As additional steps of signal transduction become better-characterized, these insights may facilitate the development of improved therapeutic approaches for controlling inflammation and connective tissue destruction in a variety of diseases.

Papillon-Lefèvre syndrome: serum immunoglobulin G (IgG) subclass antibody response to periodontopathic bacteria. A case report.

BACKGROUND: Papillon-Lefevre syndrome (PLS) is a rare autosomal recessive disorder which is characterized by palmar-plantar hyperkeratosis and rapid periodontal destruction of both primary and permanent dentitions. In this case report, we present clinical features, and microbiological and immunological findings of 40 month-old Thai male PLS patient. METHODS: Microbiological examinations consisted of bacterial culture methods utilizing selective media, morphological identification, and biochemical tests. In addition, the specific serum IgG subclass antibody titers reactive with etiologic periodontal bacteria were determined by the dot-blot immunological analysis and enzyme linked immunosorbent assay (ELISA). RESULTS: The examinations revealed that the patient harbored 3 major suspected periodontopathic microorganisms, A. actinomycetemcomitans, P. gingivalis, and P. intermedia. The patient's serum IgG1, IgG2, and IgG3, but not IgG4, titers against A. actinomycetemcomitans were dramatically increased. The predominant IgG subclass was IgG1. In contrast, the IgG titers against other tested bacteria, P. gingivalis, P. intermedia, and F. nucleatum, appeared to be similar to those of a healthy control. CONCLUSIONS: A. actinomycetemcomitans seems to play a pivotal role in the bacteria-host interaction in PLS periodontal pathogenesis. Response of the specific serum IgG subclass antibody titers against the A. actinomycetemcomitans antigen has been demonstrated. This association warrants further investigation.

Thickness of palatal masticatory mucosa associated with age.

BACKGROUND: The palatal masticatory mucosa is widely used as a donor material in periodontal plastic surgery. However, there are relatively few studies investigating the volume or thickness of the palatal mucosa. The purpose of this study was to determine the thickness of palatal masticatory mucosa in Asian subjects aged 14 to 59 years by a direct clinical technique. The associations of age and gender with the thickness of palatal mucosa were also examined. METHODS: Sixty-two systemically and periodontally healthy Asians (31 males; 31 females; age range 14 to 59 years) participated in this study. The younger age group (age 14 to 21 years) consisted of 32 subjects with a mean age of 16.8 years, whereas the older age group (age 30 to 59 years) consisted of 30 subjects with a mean age of 38.7 years. A bone-sounding method using a periodontal probe with minimal anesthesia and a prepared clear acrylic stent were utilized to assess the thickness of palatal mucosa at 15 measurement sites defined according to the gingival margin and mid-palatal line. Multiple linear regression analysis was performed to examine the associations of age and gender with the mean mucosal thickness at the subject level. The Wilcoxon test was used to determine the difference in mucosal thickness between the 2 age groups, and between gender at each measurement point. RESULTS: The mean thickness of palatal masticatory mucosa ranged from 2.0 to 3.7 mm. The younger age group had significantly thinner mucosa (mean 2.8 +/- 0.3 mm) than the older age group (mean 3.1 +/- 0.3 mm). Females had thinner mucosa than males in the same age group, but the difference was not statistically significant. Overall, the thickness of palatal mucosa increased from the canine to second molar areas and in the sites furthest from the gingival margin towards the mid-palate (with the exception of the first molar area, where significantly decreased thickness was observed). CONCLUSIONS: Within the limits of the present study, the canine and premolar areas appear to be the most appropriate donor site for grafting procedures in both young and adult individuals. The subepithelial connective tissue graft procedure can be considered as a treatment modality in young patients, since a sufficient volume of donor tissue can be obtained from the hard palate area. Other factors that may influence the thickness of palatal mucosa such as racial and genetic factors and body weight need to be further investigated.

Activation of interleukin 1beta gene transcription by human cytomegalovirus: molecular mechanisms and relevance to periodontitis.

In recent years, studies have demonstrated an association between human cytomegalovirus (HCMV) and destructive periodontal disease. It has been shown that reactivation of HCMV in periodontitis lesions may be related to progressing periodontal disease. Several possible mechanisms by which HCMV exerts periodontopathic potential have been previously proposed. These are reviewed and include the upregulation of bone resorptive cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) by active HCMV infection at the periodontitis site. This review focuses on the molecular basis of IL-1beta gene activation by HCMV immediate early (IE) gene products. A novel hypothesis is also described whereby HCMV plays a significant role in the pathogenesis of periodontal disease by the ability of its IE proteins to strongly transactivate IL-1beta gene expression. More studies are needed to further explore this hypothesis and clarify the association between HCMV and periodontitis.

NF-IL6 (C/EBPbeta ) vigorously activates il1b gene expression via a Spi-1 (PU.1) protein-protein tether.

Two classes of transcription factors, ETS and bZIP, stand out as key mediators of monocyte commitment and differentiation. The ETS domain factor Spi-1 (also called PU.1) and the bZIP factor NF-IL6 (also called C/EBPbeta) have been shown to be involved in the transcriptional regulation of interleukin-1beta gene (il1b) and other monocyte-specific genes. We now show that these two factors strongly cooperate on the il1b core promoter (-59/+12) in the absence of direct NF-IL6 binding to DNA. Transient transfection assays, using mutated il1b core promoters, showed that the Spi-1, but not the NF-IL6, binding site is absolutely required for functional cooperativity. Furthermore, the NF-IL6 transactivation domain (TAD) is functionally indispensable and more critical than that of Spi-1. Additionally, TAD-deficient NF-IL6 functions as a dominant negative for Spi-1-mediated activation, suggesting the involvement of the bZIP DNA binding domain. This is supported by the demonstration of in vitro interaction between the NF-IL6 bZIP and Spi-1 winged helix-turn-helix (wHTH) DNA binding domains, arguing that NF-IL6 vigorously activates the il1b core promoter via protein-tethered transactivation mediated by Spi-1.

Periodontitis in the child and adolescent.

Early onset periodontitis (EOP) which affects individuals thirty-five and younger is characterized by a rapid rate of bone loss and disease progression with defects in host response and a specific etiological microbial flora. Within this classification, there are three subsets of the disease: prepubertal periodontitis, juvenile periodontitis, and rapidly progressive periodontitis. The characteristics of each disease are described along with illustrative cases that will help clinicians diagnose EOP in their patients. Currently prescribed treatment modalities and guidelines from the literature are also discussed in this paper. EOP may represent a complex set of diseases that are likely to be reclassified as further advances in microbiological and genetic research are made. Clinicians should be aware of such changes in order to diagnose, treat, and refer their patients for comprehensive care.

Negative cross-talk between hematopoietic regulators: GATA proteins repress PU.1.

The process through which multipotential hematopoietic cells commit to distinct lineages involves the induction of specific transcription factors. PU.1 (also known as Spi-1) and GATA-1 are transcription factors essential for the development of myeloid and erythroid lineages, respectively. Overexpression of PU.1 and GATA-1 can block differentiation in lineages in which they normally are down-regulated, indicating that not only positive but negative regulation of these factors plays a role in normal hematopoietic lineage development. Here we demonstrate that a region of the PU.1 Ets domain (the winged helix-turn-helix wing) interacts with the conserved carboxyl-terminal zinc finger of GATA-1 and GATA-2 and that GATA proteins inhibit PU.1 transactivation of critical myeloid target genes. We demonstrate further that GATA inhibits binding of PU.1 to c-Jun, a critical coactivator of PU.1 transactivation of myeloid promoters. Finally, PU.1 protein can inhibit both GATA-1 and GATA-2 transactivation function. Our results suggest that interactions between PU.1 and GATA proteins play a critical role in the decision of stem cells to commit to erythroid vs. myeloid lineages.