Distribution of systemic clarithromycin to gingiva

Disinfection and Biocompatibility of Titanium Surfaces Treated with Glycine Powder Airflow and Triple Antibiotic Mixture: An In Vitro Study

The aim of this in vitro study was to compare three disinfection protocols of biofilm-coated machined (MAC) and acid etched (SLA) commercial pure Grade 4 Titanium disks. Samples were infected with a vial of polymicrobial biofilm to simulate peri-implantitis in vitro. Seventeen MAC and twenty SLA titanium disks were randomly assigned to: (1) glycine powder air-flow (GYPAP) for 1 min; (2) a local delivered triple paste antibiotic composed by a gel mixture with ciprofloxacin, metronidazole, and clarithromycin (3MIX) for 1 h; and (3) a combination of both (GYPAP + 3MIX). Biocompatibility of the titanium disks after each treatment protocol was assessed by measurement of adhesion and growth of adipose-derived mesenchymal stem cells (ASCs) after 24 and 72 h. A confocal laser scanning microscope (CLSM) assessed the antibacterial effect of each treatment. Data of the antibacterial efficacy and cell viability were presented as mean with standard deviation and calculated by one-way ANOVA with multiple comparisons via Bonferroni tests. Results were considered significant with p < 0.05. The higher cell viability was achieved by the 3MIX and GYPAP combination on the SLA surfaces after 72 h. CLSM analysis showed a mean ratio of dead bacteria statistically higher in the 3MIX + GYPAP group compared with the GYPAP and 3MIX subgroups (p < 0.05). In conclusion, data showed that the combination of GYPAP and 3MIX could be preferred to the other protocols, especially in presence of SLA titanium surface.

Antibiotic Therapy in Dentistry

Dental caries, pulpal necrosis, trauma, and periodontal diseases can result in dental infections which could have severe consequences that affect both soft and hard tissues of the oral cavity. Dental infections commonly present with symptoms of pain, fever, and swelling. Surgical and endodontic treatments are the early management of infected teeth, followed by antibiotic therapy. Some alternative methods also exist for treating infection such as low-level laser therapy and photodynamic therapy. Antibiotics are generally used in dental procedures to treat odontogenic infections, nonodontogenic infections, local infection, focal infection, and prophylaxis. Antibiotic prophylaxis is prescribed for patients with immunosuppressed conditions, infective endocarditis, metabolic disorders, and patients with prosthetic joints. To reduce the complications of unnecessary antibiotic prescriptions especially bacterial resistance, comprehensive guidelines should be established. It has been noted that only about 12% of dentists adequately and correctly prescribe antibiotics, which shows the importance of comprehensive guidelines. Antibiotics prescription may result in some adverse effects such as hypersensitivity reactions and dermatological and allergic disorders. Furthermore, unnecessary prescription of antibiotics could result in several serious sequelae, for example, bacterial resistance, gastric and hematological problems, and diversion of bacterial microbiota. The present review attempts to summarize the indications of antibiotic therapy in dentistry and discuss the common types of antibiotics that are routinely used in dental practice based on pharmacologic classes. Moreover, types of antibiotics that are considered safe during pregnancy and childhood are also reviewed.

[Efficacy of clarithromycin in the adjuvant treatment of chronic periodontitis: a Meta-analysis]

OBJECTIVE

To evaluate the clinical efficacy of clarithromycin (CLM) in the adjuvant treatment of chronic periodontitis systematically, obtain reasonable conclusions through evidence-based medicine, and provide guidance for clinical rational drug use.

METHODS

Literature about CLM in the adjuvant treatment of chronic periodontitis was searched in CNKI, VIP, Wanfang, Chinese Biomedical Literature Database, PubMed, ScienceDirect, and Embase databases from inception to February 2019 using a computer. Meta-analysis was performed on the homogeneous study using RevMan 5.3 software after two independent reviewers screened the literature, evaluated the quality of the study, extracted the data, and evaluated the risk of bias in the included studies.

RESULTS

Six randomized controlled trials were included in 316 subjects. The meta-analysis showed that compared with the scaling and root planning (SRP) group, the probing depth (PD) was reduced in patients with CLM and SRP [MD=-1.00, 95%CI (-1.55, -0.45), P=0.000 04]. Clinical attachment loss was obtained [MD=-0.03, 95%CI (0.43, 0.65), P<0.000 01], and the difference between the groups was statistically significant. The modified sulcus bleeding index (mSBI) was reduced [MD=-0.01, 95%CI (-0.14, 0.19), P=0.66]. No significant difference was observed between the groups, but the decrease in mSBI was more significant in CLM combined with SRP group.

CONCLUSIONS

CLM combined with subgingival SRP can achieve remarkable results in treating chronic periodontitist.

Evaluation of the Bactericidal Activity of a Hyaluronic Acid-Vehicled Clarithromycin Antibiotic Mixture by Confocal Laser Scanning Microscopy

Confocal laser scanning microscopy (CLSM) was used to evaluate the antibacterial effect and depth of action of a novel clarithromycin-containing triple antibiotic mixture, which was proposed for root canal disinfection in dental pulp regeneration. A previous study reported that this mixture had no tooth discoloration effects in vitro. After infection with Enterococcus faecalis for 3 weeks, the dentinal tubules in the cylindrical root specimens were exposed to different antibiotic mixtures: ciprofloxacin, metronidazole and minocycline (3-MIX); ciprofloxacin, metronidazole and clarithromycin (3-MIXC) and ciprofloxacin and metronidazole (2-MIX). Each antibiotic formulation was mixed with macrogol (MG) or hyaluronic acid (HA) vehicles. CLSM and viability staining were used to quantitatively analyze the mean depth of the antibacterial effect and the proportions of dead and live bacteria inside the dentinal tubules. The 3-MIX and 3-MIXC demonstrated a similar depth of action. The mean proportion of dead bacteria was similar in the 3-MIX and 3-MIXC groups, and both were statistically higher than that of 2-MIX (p = 0.014). Each antibiotic mixture showed a higher bactericidal efficacy if conveyed with HA, compared to MG (3-MIX, p = 0.019; 3-MIXC, p = 0.013 and 2-MIX, p = 0.0125). The depth of action and the antibacterial efficacy of 3-MIXC seemed comparable with 3-MIX.

Evaluating the effectiveness of clarithromycin as an adjunct to scaling and root planing: A randomized clinical trial

Background

Administration of systemic antibiotics may implement persuasive treatment effect for chronic periodontitis by intending tissue-invasive bacteria in addition to accustomed nonsurgical periodontal therapy (NSPT).

Aims

The aim of this study was to assess the ancillary effects of oral clarithromycin (CLM) along with NSPT for chronic periodontitis.

Materials and Methods

Thirty periodontitis patients were randomly divided into two equal groups in this double-blind, randomized, parallel group, and active-controlled trial: test group - scaling and root planning (SRP) plus CLM (500 mg thrice daily for 7 days, orally) was given, and control group - only SRP was done. Clinical analysis, such as gingival index (GI), probing depth (PD), and clinical attachment loss (CAL), were taken at baseline, 3 months, and 6-month intervals for both groups. Subgingival plaque samples were cultured for periodontopathic organisms. Immunological parameter C-reactive protein (CRP) levels were estimated.

Results

SPSS version 14 was used for statistical analysis. The intragroup comparison showed a significant reduction in the mean scores of all the parameters from baseline to 6 months. The intergroup comparison showed a statistically significant reduction of PD from baseline to 3 months (P < 0.001). GI, CAL, and CRP levels were also reduced but not statistically significant. The mean colony-forming units (CFU) of Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) showed a statistically significant reduction from baseline to 3 months only in the test group (P = 0.042) and (P = 0.046), respectively. There was no statistically significant reduction of Aa and Pg at 6 months.

Conclusions

CLM conceivably accepted as an addendum to NSPT for a shorter period.

Clarithromycin as an Adjunct to One-Stage Full-Mouth Ultrasonic Periodontal Debridement in Generalized Aggressive Periodontitis: A Randomized Controlled Clinical Trial

BACKGROUND

The aim of the present study is to evaluate the periodontal clinical and microbiologic responses and possible adverse effects of clarithromycin (CLM) combined with periodontal mechanical therapy in the treatment of patients with generalized aggressive periodontitis.

METHODS

Forty patients were selected and randomly assigned into one of two groups: 1) CLM (n = 20): one-stage full-mouth ultrasonic debridement (FMUD) associated with CLM (500 mg, every 12 hours for 3 days); and 2) placebo (n = 20): FMUD associated with placebo pills. Clinical and microbiologic parameters were evaluated at baseline and 3 and 6 months postoperatively.

RESULTS

Both treatments presented statistically significant clinical and microbiologic improvements. However, the CLM group presented lower means of probing depth for pockets ≥7 mm at 6 months (4.0 ± 1.7 mm) compared with the placebo group (4.7 ± 1.3 mm) (P = 0.04). In addition, the CLM group also presented greater reduction of Porphyromonas gingivalis (Pg) DNA counts at 6 months (P = 0.0001).

CONCLUSION

Results from this study suggest both treatments are effective; however, adjunct use of CLM to FMUD leads to better reduction of deep pockets and Pg at 6 months compared with FMUD alone.

Commentary: Targeting Underlying Biologic Mechanisms in Selecting Adjunctive Therapies to Improve Periodontal Treatment in Smokers: A Commentary

Despite well-established evidence that cigarette smoking is the largest modifiable risk factor for periodontal disease and has many deleterious health effects, treatment of periodontal disease in smokers remains a challenge of periodontal therapy. A recent meta-analysis revealed that adjunctive use of local delivery of antimicrobials, but not systemic antibiotic usage, with non-surgical periodontal therapy resulted in improvement in clinical periodontal parameters. Further evaluation of the current literature reveals that host modulation therapy may also result in clinical benefit in smokers. These findings may be tied to the underlying pathophysiology of periodontal disease progression in smokers and suggest that focused therapies that target known mechanisms of action are critical to the success of proposed treatments.

Salivary biomarkers in a biofilm overgrowth model

BACKGROUND

The purpose of this study is to determine whether baseline salivary inflammatory biomarkers could discriminate between different clinical levels of disease and/or detect clinical changes over a 3-week stent-induced biofilm overgrowth (SIBO) period.

METHODS

A total of 168 participants were enrolled in a 21-day experimental gingivitis investigation and grouped according to clinical measures of periodontal status of health and diseased individuals representing each of five biofilm gingival interface (BGI) periodontal groups: 1) health, all probing depth (PD) <3 mm and bleeding on probing (BOP) <10%; 2) gingivitis, all PD <3 mm and BOP ≥10%; 3) periodontitis (P)1, ≥1 site with PD >3 mm and BOP ≤10%; 4) P2, ≥1 site with PD >3 mm and BOP >10% but ≤50%; and 5) P3, ≥1 site with PD >3 mm and BOP >50%. Stents were used to prevent plaque removal during brushing over one maxillary and one mandibular posterior dental sextant for 21 days. Clinical periodontal parameters and unstimulated saliva were collected at screening, baseline, and each week during SIBO. Saliva samples were assessed for levels of 13 different biomarkers by multiplex immunoassay.

RESULTS

Higher salivary levels of interleukin (IL)-1β, matrix metalloproteinase (MMP)-3, MMP-8, MMP-9, and neutrophil gelatinase-associated lipocalin (NGAL) were found in diseased groups compared with the healthy group at baseline. Conversely, higher IL-1 receptor antagonist (ra) levels were found in healthy patients at baseline. In addition, during SIBO, MMP-1, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 levels increased across all participant groups. A stepwise linear regression model using all salivary biomarkers demonstrated that, at baseline, increased IL-1ra (P = 0.004) and IL-6 (P = 0.009) were significantly associated with change in PDs during SIBO.

CONCLUSIONS

In summary, this investigation supports salivary levels of IL-1ra and IL-6 as potential indicators for PD changes during induced gingival inflammation. In addition, participants from the BGI-P3 group (severe periodontitis) demonstrated elevated baseline levels of IL-1β, MMP-3, MMP-8, MMP-9, and NGAL compared with the other study groups, strengthening the relevance of participants' biologic phenotype on expression of salivary biomarkers.

Clarithromycin in rheumatoid arthritis: the addition to methotrexate and low-dose methylprednisolone induces a significant additive value--a 24-month single-blind pilot study

To compare the efficacy of the addition of clarithromycin (CM) to methotrexate (MTX) and methylprednisolone (MP) in active rheumatoid arthritis (RA). 32 patients with RA consecutively randomized.

CONTROL GROUP

sixteen patients treated for 24 months with MTX 10-15 mg i.m. weekly and MP 4-6 mg daily. CM group: sixteen patients treated with MTX 10-15 mg i.m. weekly and MP 4-6 mg daily for 24 months; CM therapy added in the first month (500 mg twice a day for the first 15 days followed by 500 mg a day for the remaining 15 days). Evaluation of the improvement following ACR criteria was performed at months 1 (primary endpoint), 3 and 6. Patients were furthermore observed after 12, 18 and 24 months from the study beginning. At month 1, following ACR70 improvement criteria, we found a significant additive value in CM group (10/16 = 63% vs 4/16 = 25%, p = 0.033--chi-square test). After discontinuation of CM, the difference between groups was anymore evident (month 3: CM group 10/16 = 63% vs control group 9/16 = 56%). At month 24, 7/16 (44%) in control group and 12/16 (75%) in CM group completed the follow-up. The addition of CM to MTX and MP can induce the remission ACR 70 in the majority of RA patients within 4 weeks, while MTX and MP alone need about 3 months to achieve the same result.

Periodontal tissue and serum concentration of clarithromycin after systemic administration in patients affected by chronic periodontitis

BACKGROUND

During the past two decades, dentists and microbiologists have relied on periodontal antibiotic therapy in the management of periodontitis. This association has accumulated and strengthened exponentially. Macrolides attain high therapeutic concentrations in infected tissue, so they are potentially a good choice for inhibiting invasive periodontal pathogens. Clarithromycin accumulates in phagocytes, monocytes, fibroblasts, polymorphonuclear cells, macrophages, and lymphocytes. These cells are more numerous at inflamed sites, so it is reasonable to expect clarithromycin levels to be higher in periodontally diseased sites. This study determines the distribution profile of clarithromycin in the gingiva of patients with periodontitis compared to serum after systemic administration of clarithromycin.

METHODS

Twenty patients (14 males and six females, aged 25 to 45 years) with chronic periodontitis were enrolled in the study. Gingival index and plaque index were recorded at baseline and 3 days after administration of 500 mg clarithromycin, twice daily, for 3 days. Intravenous blood and biopsy of periodontal tissue samples were taken on the third day. These samples were analyzed for detection of clarithromycin concentration using high-performance liquid chromatography.

RESULTS

Approximately 6 hours after the last dose of clarithromycin, mean clarithromycin concentrations in serum and periodontal tissue were 0.465 μg/mL and 2.61 μg/g, respectively, and the difference was statistically significant.

CONCLUSIONS

Clarithromycin can attain higher levels in gingiva than serum of patients with periodontitis. This distribution profile of clarithromycin can thus be advantageous in the management of periodontal lesions.

Evaluation of subgingivally delivered 0.5% clarithromycin as an adjunct to nonsurgical mechanotherapy in the management of chronic periodontitis: a short-term double blinded randomized control trial

OBJECTIVE

As the risk involved with systemic antimicrobials (high doses, microbial resistance, adverse reactions, etc.) restricts their use and local delivery of antimicrobials into periodontal pockets improves periodontal health, this study was designed to investigate the effects of subgingivally delivered clarithromycin (CLM; 0.5%) as an adjunct to nonsurgical mechanotherapy in chronic periodontitis subjects.

METHODS

Ninety-eight patients were categorized into two treatment groups: scaling and root planing (SRP) plus 0.5% CLM (test; group 1) and SRP plus placebo (control; group 2). Clinical parameters included gingival index (GI), sulcus bleeding index (SBI), plaque index (PI), probing depth (PD), and periodontal attachment level (PAL), recorded at 4, 8 and 12 weeks. The concentration of 0.5% CLM in gingival fluid was estimated by reverse-phase high pressure liquid chromatography. anova, the chi-square test and the Scatterthwaite test were used for statistical analysis.

RESULTS

Patients treated with SRP + CLM showed enhanced reductions in GI, SBI, and PD, and gains in PAL (P < 0.001) over time, as compared with the placebo group. However, no statistically significant differences were noted for PI. The mean concentration of CLM was detected in gingival crevicular fluid for up to 7 weeks, fulfilling the conditions for a controlled-release device.

CONCLUSION

Adjunctive use of 0.5% CLM as a controlled drug delivery system enhanced the clinical outcome up to 3 months.

Locally delivered 0.5% clarithromycin, as an adjunct to nonsurgical treatment in chronic periodontitis with well-controlled type 2 diabetes: a randomized controlled clinical trial

OBJECTIVE

Several epidemiologic studies have identified a greater incidence of periodontitis in patients with type 2 diabetes. Recent developments suggest that local delivery of antimicrobials into periodontal pockets improve periodontal health. The present study was designed to investigate the adjunctive effects of subgingivally delivered clarithromycin (CLM) (0.5% concentration) as an adjunct to scaling and root planing for treating chronic periodontitis in patients with well-controlled type 2 diabetes.

METHODS

Sixty-three patients were categorized into two treatment groups: Group 1, scaling and root planing (SRP) plus 0.5% CLM; Group 2, SRP plus placebo gel. Clinical parameters were recorded at baseline, 1, 2, and 3 months; which included gingival index (GI), sulcus bleeding index (SBI), plaque index (PI), probing depth (PD), and periodontal attachment level (PAL).

RESULTS

Both therapies resulted in significant improvements. Using a subject-based analysis, patients in Group 1 treated with SRP + CLM showed enhanced reductions in PI, GI, SBI, and PD, and gains in PAL (P < 0.001) over a period of 6 months as compared to Group 2.

CONCLUSION

Although both treatment strategies seemed to benefit the patients, the adjunctive use of 0.5% CLM as a controlled drug delivery system enhanced the clinical outcome.

Therapeutic strategies in the treatment of periodontitis

Periodontitis is a chronic inflammatory process which affects the tooth - supporting structures of the teeth. The disease is initiated by subgingival periopathogenic bacteria in susceptible periodontal sites. The host immune response towards periodontal pathogens helps to sustain periodontal disease and eventual alveolar bone loss. Although scaling and root planing is the standard treatment modality for periodontitis, it suffers from several drawbacks such as the inability to reach the base of deep pockets and doesn’t arrest migration of periodontal pathogens from other sites in the oral cavity. In order to overcome the limitations of scaling and root planning, adjunctive chemotherapeutics and host modulatory agents to the treatment are used. These therapeutic agents show substantial beneficial effects when compared to scaling and root planning alone. This review will cover an update on chemotherapeutic and past and future host immune modulatory agents used adjunctively to treat and manage periodontal diseases.

Multiple Hypothesis Testing for Experimental Gingivitis Based on Wilcoxon Signed Rank Statistics

Dental research often involves repeated multivariate outcomes on a small number of subjects for which there is interest in identifying outcomes that exhibit change in their levels over time as well as to characterize the nature of that change. In particular, periodontal research often involves the analysis of molecular mediators of inflammation for which multivariate parametric methods are highly sensitive to outliers and deviations from Gaussian assumptions. In such settings, nonparametric methods may be favored over parametric ones. Additionally, there is a need for statistical methods that control an overall error rate for multiple hypothesis testing. We review univariate and multivariate nonparametric hypothesis tests and apply them to longitudinal data to assess changes over time in 31 biomarkers measured from the gingival crevicular fluid in 22 subjects whereby gingivitis was induced by temporarily withholding tooth brushing. To identify biomarkers that can be induced to change, multivariate Wilcoxon signed rank tests for a set of four summary measures based upon area under the curve are applied for each biomarker and compared to their univariate counterparts. Multiple hypothesis testing methods with choice of control of the false discovery rate or strong control of the family-wise error rate are examined.

Azithromycin concentrations in blood and gingival crevicular fluid after systemic administration

BACKGROUND

Azithromycin is a macrolide antibiotic that is active against several periodontal pathogens. Macrolides are taken up and concentrated inside gingival fibroblasts, which could influence their pharmacokinetics. This study tests the hypothesis that steady-state levels of azithromycin are higher and more sustained in gingival crevicular fluid (GCF) than in serum.

METHODS

Four healthy patients received an initial dose of 500-mg azithromycin followed by 250-mg doses on each of the next 2 days. Serum and GCF samples were obtained 2 hours after the last dose on day 2, and on days 4 and 7. GCF samples were collected from maxillary posterior sites with paper strips. The strips were pooled and eluted with high-purity water. After extraction, the azithromycin content of the serum samples and GCF eluates was determined with an agar diffusion bioassay.

RESULTS

On days 2, 4, and 7, the concentrations of azithromycin in blood serum were 0.22 ± 0.02, 0.08 ± 0.02, and 0.04 ± 0.01 μg/mL, respectively. The concentrations in GCF were 8.82 ± 1.25, 7.90 ± 1.72, and 7.38 ± 1.15 μg/mL, respectively. Mean GCF levels were significantly higher than mean serum levels (P ≤0.02; paired t test).

CONCLUSIONS

The findings demonstrate that the pharmacokinetic profiles of azithromycin are different in GCF and serum. At steady state, azithromycin concentrations in GCF were higher and more sustained than those in serum. Based on previous studies, the levels observed in GCF were above the minimal inhibitory concentration for Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and Prevotella intermedia.

Clarithromycin accumulation by phagocytes and its effect on killing of Aggregatibacter actinomycetemcomitans

BACKGROUND

Clarithromycin inhibits several periodontal pathogens and is concentrated inside gingival fibroblasts and epithelial cells by an active transporter. We hypothesized that polymorphonuclear leukocytes (PMNs) and less mature myeloid cells possess a similar transporter for clarithromycin. It is feasible that clarithromycin accumulation inside PMNs could enhance their ability to kill Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans).

METHODS

To test the first hypothesis, purified PMNs and cultured HL-60 cells were incubated with [(3)H]-clarithromycin. Clarithromycin transport was assayed by measuring changes in cell-associated radioactivity over time. The second hypothesis was examined with PMNs loaded by incubation with clarithromycin (5 μg/ml). Opsonized bacteria were incubated at 37°C with control and clarithromycin-loaded PMNs.

RESULTS

Mature human PMNs, HL-60 cells differentiated into granulocytes, and undifferentiated HL-60 cells all took up clarithromycin in a saturable manner. The kinetics of uptake by all yielded linear Lineweaver-Burk plots. HL-60 granulocytes transported clarithromycin with a K(m) of ≈250 μg/ml and a V(max) of 473 ng/min/10(6) cells, which were not significantly different from the values obtained with PMNs. At steady state, clarithromycin levels inside HL-60 granulocytes and PMNs were 28- to 71-fold higher than extracellular levels. Clarithromycin-loaded PMNs killed significantly more A. actinomycetemcomitans and achieved shorter half-times for killing than control PMNs when assayed at a bacteria-to-PMN ratio of 100:1 (P <0.04). At a ratio of 30:1, these differences were not consistently significant.

CONCLUSIONS

PMNs and less mature myeloid cells possess a transporter that takes up and concentrates clarithromycin. This system could help PMNs cope with an overwhelming infection by A. actinomycetemcomitans.

Changes in gingival crevicular fluid inflammatory mediator levels during the induction and resolution of experimental gingivitis in humans

AIM

The goal of this study is to characterize the changes in 33 biomarkers within the gingival crevicular fluid during the 3-week induction and 4-week resolution of stent-induced, biofilm overgrowth mediated, experimental gingivitis in humans.

METHODS

Experimental gingivitis was induced in 25 subjects for 21 days followed by treatment with a sonic powered toothbrush for 28 days. Clinical indices and gingival crevicular fluids were collected weekly during induction and biweekly during resolution. Samples were analysed using a bead-based multiplexing analysis for the simultaneous measurements of 33 biomarkers within each sample including cytokines, matrix-metalloproteinases (MMPs) and adipokines. Prostaglandin-E(2) was measured by enzyme-linked immunoadsorbant assay. Statistical testing using general linear models with structured covariance matrices were performed to compare stent to contralateral (non-stent) changes in clinical signs and in biomarker levels over time.

RESULTS

Gingivitis induction was associated with a significant 2.6-fold increase in interleukin 1-beta (IL-beta), a 3.1-fold increase in IL-1alpha and a significant decrease in multiple chemokines as well as MMPs-1, -3 and 13. All changes in clinical signs and mediators rebounded to baseline in response to treatment in the resolution phase.

CONCLUSIONS

Stent-induced gingivitis is associated with marked, but reversible increases in IL-alphaa and IL-1beta with suppression of multiple chemokines as well as selected MMPs.

Azithromycin decreases crevicular fluid volume and mediator content

Azithromycin enhances the response to root planing and produces anti-inflammatory effects in treating chronic lung disease. This led us to hypothesize that azithromycin inhibits inflammatory mediator production in gingiva, leading to decreased gingival crevicular fluid (GCF) volume. To test this hypothesis, ten periodontally healthy volunteers received azithromycin every 24 hours for 48 hours. GCF samples were collected from 12 maxillary interproximal sites prior to azithromycin (baseline) and 2, 4, 7, and 14 days later. Samples were assayed for IL-1beta, IL-8, TNF-alpha, VEGF, IL-6, and IL-10. With azithromycin treatment, GCF volume decreased significantly on days 2 through 7 (P < 0.05), but increased toward baseline levels on day 14. This was accompanied by a transient decrease in the content of IL-1beta, IL-8, TNF-alpha, and VEGF (P < 0.05). IL-6 and IL-10 were not detected. Since plaque was absent throughout the study, the findings suggest that azithromycin produces anti-inflammatory effects in gingiva.

Gingival transcriptome patterns during induction and resolution of experimental gingivitis in humans

BACKGROUND

To our knowledge, changes in the patterns of whole-transcriptome gene expression that occur during the induction and resolution of experimental gingivitis in humans were not previously explored using bioinformatic tools.

METHODS

Gingival biopsy samples collected from 14 subjects during a 28-day stent-induced experimental gingivitis model, followed by treatment, and resolution at days 28 through 35 were analyzed using gene-expression arrays. Biopsy samples were collected at different sites within each subject at baseline (day 0), at the peak of gingivitis (day 28), and at resolution (day 35) and processed using whole-transcriptome gene-expression arrays. Gene-expression data were analyzed to identify biologic themes and pathways associated with changes in gene-expression profiles that occur during the induction and resolution of experimental gingivitis using bioinformatic tools.

RESULTS

During disease induction and resolution, the dominant expression pathway was the immune response, with 131 immune response genes significantly up- or downregulated during induction, during resolution, or during both at P <0.05. During induction, there was significant transient increase in the expression of inflammatory and oxidative stress mediators, including interleukin (IL)-1 alpha (IL1A), IL-1 beta (IL1B), IL8, RANTES, colony stimulating factor 3 (CSF3), and superoxide dismutase 2 (SOD2), and a decreased expression of IP10, interferon inducible T-cell alpha chemoattractant (ITAC), matrix metalloproteinase 10 (MMP10), and beta 4 defensin (DEFB4). These genes reversed expression patterns upon resolution in parallel with the reversal of gingival inflammation.

CONCLUSIONS

A relatively small subset (11.9%) of the immune response genes analyzed by array was transiently activated in response to biofilm overgrowth, suggesting a degree of specificity in the transcriptome-expression response. The fact that this same subset demonstrates a reversal in expression patterns during clinical resolution implicates these genes as being critical for maintaining tissue homeostasis at the biofilm-gingival interface. In addition to the immune response pathway as the dominant response theme, new candidate genes and pathways were identified as being selectively modulated in experimental gingivitis, including neural processes, epithelial defenses, angiogenesis, and wound healing.

Clarithromycin transport by gingival fibroblasts and epithelial cells

Macrolide antibiotics penetrate cells, but the mechanism by which this occurs is unclear. The objective of this study was to characterize the mechanisms of clarithromycin uptake by gingival fibroblasts and oral epithelium. Cultured human gingival fibroblasts and SCC-25 cells were incubated with [(3)H]-clarithromycin. We assayed clarithromycin transport by measuring cell-associated radioactivity over time. Fibroblasts and epithelial cells rapidly accumulated clarithromycin, attaining steady-state intracellular concentrations within 15 minutes. Incubation in medium containing 2 mug/mL clarithromycin yielded steady-state intracellular concentrations of 75.8 mug/mL in fibroblasts and 6.6 mug/mL in SCC-25 cells. Clarithromycin transport exhibited Michaelis-Menten kinetics and was inhibited below 37 degrees C. The Michaelis constants for fibro-blasts and SCC-25 cells were 78.4 and 227 mug/mL, respectively, while the maximum transport velocities were 264 and 381 ng/min/10(6) cells, respectively. Thus, both types of cells take up clarithromycin via a concentrative active transport system. By increasing intracellular clarithromycin levels, this system may enhance the effectiveness of clarithromycin against invasive periodontal pathogens.