Electrolyzed Saline Targets Biofilm Periodontal Pathogens In Vitro.

Preventing the development and recurrence of periodontal diseases often includes antimicrobial mouthrinses to control the growth of the periodontal pathogens. Most antimicrobials are nonselective, targeting the symbiotic oral species as well as the dysbiosis-inducing ones. This affects the overall microbial composition and metabolic activity and consequently the host-microbe interactions, which can be detrimental (associated with inflammation) or beneficial (health-associated). Consequently, guiding the antimicrobial effect for modulating the microbial composition to a health-associated one should be considered. For such an approach, this study investigated electrolyzed saline as a novel rinse. Electrolyzed saline was prepared from sterile saline using a portable electrolysis device. Multispecies oral homeostatic and dysbiotic biofilms were grown on hydroxyapatite discs and rinsed daily with electrolyzed saline (EOS). Corresponding positive (NaOCl) and negative (phosphate-buffered saline) controls were included. After 3 rinses, biofilms were analyzed with viability quantitative polymerase chain reaction and scanning electron microscopy. Supernatants of rinsed biofilms were used for metabolic activity analysis (high-performance liquid chromatography) through measuring organic acid content. In addition, human oral keratinocytes (HOKs) were exposed to EOS to test biocompatibility (cytotoxicity and inflammation induction) and also to rinsed biofilms to assess their immunogenicity after rinsing. Rinsing the dysbiotic biofilms with EOS could reduce the counts of the pathobionts (>3 log10 Geq/mm2 reduction) and avert biofilm dysbiosis (≤1% pathobiont abundance), leading to the dominance of commensal species (≥99%), which altered both biofilm metabolism and interleukin 8 (IL-8) induction in HOKs. EOS had no harmful effects on homeostatic biofilms. The scanning electron micrographs confirmed the same. In addition, tested concentrations of EOS did not have any cytotoxic effects and did not induce IL-8 production in HOKs. EOS showed promising results for diverting dysbiosis in in vitro rinsed biofilms and controlling key periopathogens, with no toxic effects on commensal species or human cells. This novel rinsing should be considered for clinical applications.

Probiotic strains of Lactobacillus brevis and Lactobacillus plantarum as adjunct to non-surgical periodontal therapy: 3-month results of a randomized controlled clinical trial.

OBJECTIVES: To determine if periodontitis patients benefit from treatment with Lactobacillus brevis and Lactobacillus plantarum strains, applied into periodontal pockets as gel and thereafter taken as lozenges, as an adjunct to scaling and root planing (SRP). MATERIALS AND METHODS: In a double-blind, randomized, placebo-controlled trial, 40 patients received scaling and root planing (SRP) in two sessions within 7 days. Patients then received either probiotic gel and lozenges (n = 20) or placebo (n = 20). The primary outcome variable was the number of diseased sites (DS: PD > 4 mm + BOP) at the 3-month re-evaluation. The effects of gender, age, probiotic therapy, presence of Porphyromonas gingivalis or Aggregatibacter actinomycetemcomitans, smoking, tooth being a molar and interdental location were evaluated using a multivariate multilevel logistic regression model. RESULTS: The number of DS after 3 months was similar in the test (Me = 8, IQR = 5-11) and control (Me = 5, IQR = 1-10) groups. Both groups showed substantial but equivalent improvements in periodontal parameters. The logistic regression showed higher odds for the healing of gingival bleeding (OR = 2.12, p = 0.048) and lower odds for the healing of DS (OR = 0.51; p < 0.001) in the probiotic group. CONCLUSIONS: Patients with periodontitis benefit from adjunctive use of probiotics containing L. brevis and L. plantarum in terms of reduction of gingival bleeding. However, adjunctive probiotics increase the number of persisting diseased sites with PD > 4 mm and BOP. CLINICAL RELEVANCE: The adjunctive use of probiotics containing L. brevis and L. plantarum strains in treating chronic periodontitis results in a higher number of residual diseased sites when compared with SRP + placebo; its use is therefore unfounded.

Anti-NGF treatment reduces bone resorption in periodontitis.

Periodontitis is characterized by periodontal tissue destruction, including the alveolar bone. One of its critical components is the release of pro-inflammatory neuropeptides from sensory nerve endings innervating the periodontium. Since nerve growth factor (NGF) has been reported to up-regulate neuropeptides in sensory neurons, we hypothesized that it would be increased in ligature-induced periodontitis in rats, and that systemic NGF neutralization would reduce the periodontitis-associated alveolar bone resorption. Real-time PCR analysis disclosed a statistically significant time-dependent up-regulation of NGF mRNA in gingiva during 2 weeks of periodontitis. Interestingly, NGF up-regulation was also detected in the contralateral gingiva. In addition, immunohistochemistry of trigeminal ganglion neurons innervating the gingivomucosa demonstrated increased expression of TrkA receptor for NGF. Systemic anti-NGF treatment during periodontitis significantly reduced interleukin-1beta expression in gingiva and bilateral alveolar bone resorption. This suggests that NGF promotes periodontal inflammation and implicates a possible use of anti-NGF treatment in periodontitis.

Muscle activity-resistant acetylcholine receptor accumulation is induced in places of former motor endplates in ectopically innervated regenerating rat muscles.

Expression of acetylcholine receptors (AChRs) in the extrajunctional muscle regions, but not in the neuromuscular junctions, is repressed by propagated electric activity in muscle fibers. During regeneration, subsynaptic-like specializations accumulating AChRs are induced in new myotubes by agrin attached to the synaptic basal lamina at the places of former motor endplates even in the absence of innervation. We examined whether AChRs still accumulated at these places when the regenerating muscles were ectopically innervated and the former synaptic places became extrajunctional. Rat soleus muscles were injured by bupivacaine and ischemia to produce complete myofiber degeneration. The soleus muscle nerve was permanently severed and the muscle was ectopically innervated by the peroneal nerve a few millimeters away from the former junctional region. After 4 weeks of regeneration, the muscles contracted upon nerve stimulation, showed little atrophy and the cross-section areas of their fibers were completely above the range in non-innervated regenerating muscles, indicating successful innervation. Subsynaptic-like specializations in the former junctional region still accumulated AChRs (and acetylcholinesterase) although no motor nerve endings were observed in their vicinity and the cross-section area of their fibers clearly demonstrated that they were ectopically innervated. We conclude that the expression of AChRs at the places of the former neuromuscular junctions in the ectopically innervated regenerated soleus muscles is activity-independent.

Acetylcholinesterase in the neuromuscular junction.

New findings regarding acetylcholinesterase (AChE) in the neuromuscular junction (NMJ), obtained in the last decade, are briefly reviewed. AChE is highly concentrated in the NMJs of vertebrates. Its location remains stable after denervation in mature rat muscles but not in early postnatal muscles. Agrin in the synaptic basal lamina is able to induce sarcolemmal differentiations accumulating AChE even in the absence of a nerve ending. Asymmetric A12 AChE form is the major molecular form of AChE in vertebrate NMJs. Extrajunctional suppression of this form is a developmental phenomenon. Motor nerve is able to reinduce expression of the A12 AChE form in the ectopic NMJs even in muscles with complete extrajunctional suppression of this form. The 'tail' of the A12 AChE form is made of collagen Q. It contains domains for binding AChE to basal lamina with ionic and covalent interactions. Muscle activity is required for normal AChE expression in muscles and its accumulation in the NMJs. In addition, the pattern of muscle activation also regulates AChE activity in the NMJs, demonstrating that the pattern of synaptic transmission is able to modulate one of the key synaptic components.