Periodontal healing and bone regeneration in response to azithromycin

Sestrin2 inhibits RANKL-induced osteoclastogenesis through AMPK activation and ROS inhibition

Sestrins are stress-responsive proteins with antioxidant properties. They participate in cellular redox balance and protect against oxidative damage. This study investigated the effects of Sestrin2 (Sesn2) on osteoclast differentiation and function. Overexpressing Sesn2 in osteoclast precursor cells significantly inhibited receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis. This was assessed as reduced expression of various osteoclast markers, including c-Fos, nuclear factor of activated T cells 1 (NFATc1), osteoclast-associated receptor, tartrate-resistant acid phosphatase, and cathepsin K. Conversely, downregulation of Sesn2 produced the opposite effect. Mechanistically, Sesn2 overexpression enhanced AMPK activation and the nuclear translocation of nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2), promoting antioxidant enzymes. Moreover, azithromycin (Azm) induced Sesn2 expression, which suppressed RANKL-induced osteoclast differentiation. Specifically, Azm treatment reduced RANKL-induced production of reactive oxygen species in osteoclasts. Furthermore, intraperitoneal administration of Azm ameliorated RANKL-induced bone loss by reducing osteoclast activity in mice. Taken together, our results suggested that Azm-induced Sesn2 act as a negative regulator of RANKL-induced osteoclast differentiation through the AMPK/NFATc1 signaling pathway. Concisely, targeting Sesn2 can be a potential pharmacological intervention in osteoporosis.

Comparative Study of Azithromycin Versus Doxycycline Effect on the Resistin Level in Periodontitis Patients With Type 2 Diabetes: A Randomized Controlled Clinical Trial

AIM

The present study aimed to determine if azithromycin (AZM) and doxycycline therapy, as an adjunct to scaling and root planning (SRP), modulate host response and improve clinical outcomes in periodontitis patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

Forty-five periodontal sites in 15 periodontitis patients with T2DM received nonsurgical periodontal therapy (NSPT). In Group I, patients were placebo (not receiving any medication), Group II patients received systemic AZM therapy (AZM 250 mg/day for five days), and Group III patients received doxycycline (20 mg twice per day for three months. The resistin level was collected and measured by enzyme-linked immunosorbent assay (ELISA). Gingival index (GI), probing depth (PD), and clinical attachment level (CAL) were recorded at baseline, one-month, and three-month intervals.

RESULTS

All groups showed improvement in clinical parameters and resistin levels throughout the study. The mean resistin level at three months was the highest in Group I and the lowest in Group III. Patients in Group II showed a larger decrease in mean PD than those in Group I and III. Group III had the highest gain in mean CAL, with an increase of 1.78 mm in attachment.

CONCLUSION

Resistin might be a useful indicator of current disease status. In addition, benefits from adjunctive systemic use of AZM and doxycycline have been administered with non-surgical periodontal therapy.

Role of various pharmacologic agents in alveolar bone regeneration: A review

Alveolar bone and gingiva are components of the periodontium that house the tooth. It constantly adapts itself to the masticatory forces and position of the tooth. However, localized diseases like chronic periodontitis and certain systemic diseases destroy periodontal tissues, which include the alveolar bone. Various pharmacological agents are being explored for their pleiotropic properties to combat the destruction of alveolar bone. This review focuses on the role of pharmacological agents in alveolar bone regeneration.

Effect of Administration of Azithromycin and/or Probiotic Bacteria on Bones of Estrogen-Deficient Rats

The gut microbiota plays an important role in maintaining homeostasis, including that of the skeletal system. Antibiotics may affect the skeletal system directly or indirectly by influencing the microbiota. Probiotic bacteria have been reported to favorably affect bones in conditions of estrogen deficiency. The aim of this study was to investigate the effects of azithromycin (AZM) administered alone or with probiotic bacteria (Lactobacillus rhamnosus; LR) on bones in estrogen-deficient rats. The experiments were carried out on mature rats divided into five groups: non-ovariectomized (NOVX) control rats, ovariectomized (OVX) control rats, and OVX rats treated with: LR, AZM, or AZM with LR. The drugs were administered for 4 weeks. Serum biochemical parameters, bone mineralization, histomorphometric parameters, and mechanical properties were examined. Estrogen deficiency increased bone turnover and worsened cancellous bone microarchitecture and mechanical properties. The administration of LR or AZM slightly favorably affected some skeletal parameters of estrogen-deficient rats. The administration of AZM with LR did not lead to the addition of the effects observed for the separate treatments, indicating that the effects could be microbiota-mediated.

Effect of Azithromycin on Mineralized Nodule Formation in MC3T3-E1 Cells

Azithromycin displays immunomodulatory and anti-inflammatory effects in addition to broad-spectrum antimicrobial activity and is used to treat inflammatory diseases, including respiratory and odontogenic infections. Few studies have reported the effect of azithromycin therapy on bone remodeling processes. The aim of this study was to examine the effects of azithromycin on the osteogenic function of osteoblasts using osteoblast-like MC3T3-E1 cells. Cells were cultured in the presence of 0, 0.1, 1, and 10 µg/mL azithromycin, and cell proliferation and alkaline phosphatase (ALPase) activity were determined. In vitro mineralized nodule formation was detected with alizarin red staining. The expression of collagenous and non-collagenous bone matrix protein was determined using real-time PCR or enzyme-linked immunosorbent assays. In cells cultured with 10 µg/mL azithromycin, the ALPase activity and mineralized nodule formation decreased, while the type I collagen, bone sialoprotein, osteocalcin, and osteopontin mRNA expression as well as osteopontin and phosphorylated osteopontin levels increased. These results suggest that a high azithromycin concentration (10 µg/mL) suppresses mineralized nodule formation by decreasing ALPase activity and increasing osteopontin production, whereas low concentrations (≤l.0 µg/mL) have no effect on osteogenic function in osteoblastic MC3T3-E1 cells.

Randomized clinical trial of the effects of azithromycin use in the treatment of peri-implantitis

BACKGROUND

The aim of this clinical trial was to establish a proof of concept that the adjunctive use of systemic azithromycin (AZM) in conjunction with mechanical debridement has an increased benefit in reducing soft tissue inflammation in the treatment of peri-implantitis.

METHODS

In a randomized, double-blind, clinical trial, the treatment group (nine patients) received AZM as well as mechanical debridement in a single course of treatment, whereas the control group (eight patients) received a placebo and mechanical debridement. The primary outcome variables studied were bleeding on probing, suppuration, pocket probing depth and gingival recession. The secondary variables studied were gingival index, plaque index, microbiological and interleukin-1β status. The observation period was 6 months.

RESULTS

Over the 6 months' observation period, the treatment patients showed a consistently greater reduction of gingival inflammation and an improvement in soft tissue healing than the control patients.

CONCLUSIONS

The adjunctive use of a single course of systemic azithromycin can assist in the control of peri-implant mucositis in the treatment of peri-implantitis.

Anti-inflammatory effect of active nanofibrous polymeric membrane bearing nanocontainers of atorvastatin complexes

Aim: We developed polymeric membranes for local administration of nonsoluble anti-inflammatory statin, as potential wound patch in rheumatic joint or periodontal lesions. Methods: Electrospun polycaprolactone membranes were fitted with polysaccharide-atorvastatin nanoreservoirs by using complexes with poly-aminocyclodextrin. Characterization methods are UV-Visible and X-ray photoelectron spectroscopy, molecular dynamics, scanning and transmission electron microscopy. In vitro, membranes were seeded with macrophages, and inflammatory cytokine expression were monitored. Results & conclusion: Stable inclusion complexes were formed in solution (1:1 stability constant 368 M- 1, -117.40 kJ mol- 1), with supramolecular globular organization (100 nm, substructure 30 nm). Nanoreservoir technology leads to homogeneous distribution of atorvastatin calcium trihydrate complexes in the membrane. Quantity embedded was estimated (70–90 μg in 30 μm × 6 mm membrane). Anti-inflammatory effect by cell contact-dependent release reached 60% inhibition for TNF-α and 80% for IL-6. The novelty resides in the double protection offered by the cyclodextrins as drug molecular chaperones, with further embedding into biodegradable nanoreservoirs. The strategy is versatile and can target other diseases.

Antimicrobial and Immunomodulatory Surface-Functionalized Electrospun Membranes for Bone Regeneration

Guided bone regeneration (GBR) is a surgical procedure utilizing occlusive membranes for providing space maintenance and enabling selective repopulation of the damaged area. While this technique is effective in regenerating bone, bacterial infiltration occurs frequently and can compromise the regenerative outcome. In this study, the authors describe the development and characterization of a GBR membrane made of medical grade polycaprolactone (mPCL) electrospun fibers with antibacterial and immunomodulatory properties. This is achieved by the immobilization of the antibiotic azithromycin into the membrane via a solvent evaporation technique leading to a sustained release of the drug over 14 d. In vitro testing shows that this controlled release of azithromycin is proficient at inhibiting the growth of Staphylococcus aureus for 14 d. Implantation of azithromycin loaded mPCL membrane in a rodent calvarial defect induces macrophage polarization toward the M2 phenotype after one week and results in significantly more bone regeneration eight weeks post-surgery. The results suggest that this antibacterial membrane should be effective at preventing infection and also impacts on the macrophage polarization enhancing bone regeneration. The drug loading technique developed in this study is simple, effective with a strong potential for clinical translation and can be applied to different types of scaffolds and implants for applications in craniofacial and orthopedics applications.

Subantibiotic dose of azithromycin attenuates alveolar bone destruction and improves trabecular microarchitectures in a rat model of experimental periodontitis: A study using micro-computed tomography

Azithromycin, a macrolide antibiotic, has anti-inflammatory and immunomodulatory activities apart from its antibacterial properties. In this study, we examined the efficacy of subantibiotic dose of azithromycin on ligature-induced periodontitis in rats using micro-computed tomography (micro-CT) imaging and bone parameter analysis. Male Sprague-Dawley rats were allocated to the following four groups: non-ligation (NL) group; ligation-only (L) group; ligation-plus-subantibiotic dose azithromycin (SA) group; and 4) ligation-plus-antibiotic dose azithromycin (AA) group. The rats from Groups L, SA and AA were subjected to periodontitis by placing a ligature around lower right first molar. Immediately after ligation, the rats in SA and AA groups received daily intraperitoneal injections of azithromycin at a dosage of 3.5 or 10mg/kg body weight, respectively. The ligatures were maintained for 2weeks at which time the rats had their mandibles hemisected for micro-CT analysis. Subantibiotic dose of azithromycin strongly suppressed reductions in alveolar bone height and bone volume fraction caused by experimental periodontitis. When subantibiotic dosage of azithromycin was administered to rats, ligature-induced alterations in microarchitectural parameters of trabecular bone were significantly reversed. Rats treated with subantibiotic dose of azithromycin presented no significant difference compared to rats with antibiotic dosage in all parameters. While further studies are necessary, subantibiotic dose of azithromycin could be utilized as a host modulator for the treatment of periodontitis.

Azithromycin as an adjunct to non-surgical periodontal therapy: a systematic review

The aim of this study was to investigate the current published work relating to the clinical benefits of the use of systemic azithromycin as an adjunct to non-surgical periodontal therapy. A published work search of PubMed, EMBASE and Cochrane Register of Controlled Trials up to 27 April 2016 was undertaken. The large degree of heterogeneity in the types of studies, treatment protocols, test subjects, sample size and exclusion criteria indicated that the use of narrative synthesis of all relevant studies was a valid method of review. Of the 194 eligible studies, 15 were found to be of relevance. The majority of studies demonstrated an additional clinical benefit when azithromycin is used as an adjunct to non-surgical periodontal therapy, particularly in deeper pockets (≥6 mm). In conclusion, the current body of research on the adjunctive use of systemic azithromycin in non-surgical periodontal therapy suggests there is a clinical benefit and that this benefit is greatest in deeper initial pockets (≥6 mm). The findings also suggest that future studies need to be more careful in subject selection to identify susceptible patients or at risk sites, both the immunoregulatory effects and antibiotic resistance of azithromycin needs to be reported, and that study populations need to be more homogeneous.

Cytokines during periodontal wound healing: potential application for new therapeutic approach

Regeneration of periodontal tissues is one of the main goals of periodontal therapy. However, current treatment, including surgical approach, use of membrane to allow maturation of all periodontal tissues, or use of enamel matrix derivatives, presents limitations in their indications and outcomes leading to the development of new tissue engineering strategies. Several cytokines are considered as key molecules during periodontal destruction process. However, their role during each phase of periodontal wound healing remains unclear. Control and modulation of the inflammatory response and especially, release of cytokines or activation/inhibition in a time- and spatial-controlled manner may be a potential perspective for periodontal tissue engineering. The aim of this review was to summarize the specific role of several cytokines during periodontal wound healing and the potential therapeutic interest of inflammatory modulation for periodontal regeneration especially related to the expression sequence of cytokines.

Resolution of Localized Chronic Periodontitis Associated with Longstanding Calculus Deposits

This report, which is based on nonstandardized serial radiographs obtained over a period of 15 years, documents a case of localized chronic periodontitis associated with progressive deposition of calculus on the distal aspect of a mandibular second molar. The site was treated by scaling and root planing, followed by a course of adjunctive systemic azithromycin. Treatment yielded favorable reductions in probing depth and clinical inflammation, leaving only few isolated sites with pockets no deeper than 4 mm. Two years after completion of active treatment, there was radiographic evidence of increased bone density distal to the second molar.

Azithromycin suppresses human osteoclast formation and activity in vitro

Azithromycin is an antibiotic with anti-inflammatory properties used as an adjunct to treat periodontitis, a common inflammatory mediated condition featuring pathologic alveolar bone resorption. This study aimed to determine the effect of azithromycin on human osteoclast formation and resorptive activity in vitro. Osteoclasts were generated from peripheral blood mononuclear cells stimulated with macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor kappa B (RANK) ligand. The effects of azithromycin at concentrations ranging from 0.5 to 40 µg/ml were tested. Osteoclast formation and activity, acidification, actin ring formation and expression of mRNA, and protein encoding for key osteoclast genes were assessed. The results demonstrated that azithromycin reduced osteoclast resorptive activity at all concentrations tested with osteoclast formation being significantly reduced at the higher concentrations (20 and 40 µg/ml). mRNA and protein expression of key osteoclast transcription factor Nuclear Factor of Activated T cells (NFATc1) was significantly reduced by azithromycin at later stages of osteoclast development (day 17). Azithromycin also reduced tumor necrosis factor receptor associated factor-6 (TRAF6) mRNA expression at day 14, and cathepsin K mRNA expression at days 14 and 17. Integrin β3 and MMP-9 mRNA expression was reduced by azithromycin at day 17 in osteoclasts cultured on dentine. The osteoclast proton pump did not appear to be affected by azithromycin, however formation of the actin ring cytoskeleton was inhibited. This study demonstrates that azithromycin inhibits human osteoclast function in vitro, which may account for at least some of the beneficial clinical effects observed with azithromycin treatment in periodontitis.

Azithromycin in periodontal treatment: more than an antibiotic

Azithromycin is a macrolide antibiotic used extensively in medicine for the treatment of a wide range of infections such as upper respiratory tract infections, middle ear infections, sexually transmitted infections and trachoma. It is also effective against the most common periodontopathogens. The versatility of the macrolides extends beyond their antibiotic properties as a result of their well-documented immune-modulating/anti-inflammatory effects. Macrolides, including azithromycin, are therefore used to treat diseases not associated with bacteria, such as severe asthma, chronic obstructive pulmonary diseases and, more recently, cystic fibrosis. Azithromycin is concentrated in neutrophils, macrophages and particularly fibroblasts; all of these cells are central players in the pathogenesis of most periodontal diseases. This paper reviews the diverse properties of azithromycin and the clinical periodontal studies of its effects in both the treatment of periodontitis and in resolving drug-related gingival overgrowth. Evidence exists to support the use of a single course of azithromycin in the treatment of advanced periodontal diseases. Azithromycin could have a triple role in the treatment and resolution of periodontal diseases: suppressing periodontopathogens, anti-inflammatory activity and healing through persistence at low levels in macrophages and fibroblasts in periodontal tissues, even after a single course of three tablets. If future periodontal research confirms these properties, it could become a valuable host-modulator in periodontal treatment.