Effect of Locally Delivered Minocycline on the Profile of Subgingival Bacterial Genera in Patients with Periodontitis: A Prospective Pilot Study

Fusobacterium nucleatum determines the expression of amphetamine-induced behavioral responses through an epigenetic phenomenon

Amphetamines (AMPHs) are psychostimulants commonly used for the treatment of neuropsychiatric disorders. They are also misused (AMPH use disorder; AUD), with devastating outcomes. Recent studies have implicated dysbiosis in the pathogenesis of AUD. However, the mechanistic roles of microbes in AUD are unknown. Fusobacterium nucleatum (Fn) is a bacterium that increases in abundance in both rats and humans upon AMPH exposure. Fn releases short-chain fatty acids (SCFAs), bacterial byproducts thought to play a fundamental role in the gut-brain axis as well as the pathogenesis of AUD. We demonstrate that in gnotobiotic Drosophila melanogaster, colonization with Fn or dietary supplementation of the SCFA butyrate, a potent inhibitor of histone deacetylases (HDACs), enhances the psychomotor and rewarding properties of AMPH as well as its ability to promote male sexual motivation. Furthermore, solely HDAC1 RNAi targeted inhibition recapitulates these enhancements, pointing to a specific process underlying this Fn phenomenon. Of note is that the expression of these AMPH behaviors is determined by the increase in extracellular dopamine (DA) levels that result from AMPH-induced reversal of DA transporter (DAT) function, termed non-vesicular DA release (NVDR). The magnitude of AMPH-induced NVDR is dictated, at least in part, by DAT expression levels. Consistent with our behavioral data, we show that Fn, butyrate, and HDAC1 inhibition enhance NVDR by elevating DAT expression. Thus, the participation of Fn in AUD stems from its ability to release butyrate and inhibit HDAC1. These data offer a microbial target and probiotic interventions for AUD treatment.

Construction of a versatile in vitro cultivation screening platform using human oral microbiota

We developed a simulation model of human oral microbiota using Bio Palette oral medium (BPOM) containing 0.02% glucose and lower bacterial nitrogen sources, derived from saliva and dental plaque. By decreasing the concentration of Gifu anaerobic medium (GAM) from 30 to 10 g L-1 , we observed increased ratios of target pathogenic genera, Porphyromonas and Fusobacterium from 0.5% and 1.7% to 1.2% and 3.5%, respectively, in the biofilm on hydroxyapatite (HA) discs. BPOM exhibited the higher ratios of Porphyromonas and Fusobacterium, and amplicon sequence variant number on HA, compared with GAM, modified GAM and basal medium mucin. Mixing glycerol stocks of BPOM culture solutions from four human subjects resulted in comparable ratios of these bacteria to the original saliva. In this simulation model, sitafloxacin showed higher inhibitory effects on P. gingivalis than minocycline hydrochloride at a low dosage of 0.1 μg mL-1 . Probiotics such as Streptococcus salivarius and Limosilactobacillus fermentum also showed significant decreases in Porphyromonas and Fusobacterium ratios on HA, respectively. Overall, the study suggests that BPOM with low carbon and nutrients could be a versatile platform for assessing the efficacy of antibiotics and live biotherapeutics in treating oral diseases caused by Porphyromonas and Fusobacterium.

Effectiveness of chlorhexidine gels and chips in Periodontitis Patients after Scaling and Root Planing: a systematic review and Meta-analysis

Periodontal pockets are characteristic of periodontitis. Scaling and root planing is the gold standard for periodontitis treatment. Additional local antimicrobials are recommended in patients with a probing depth of ≥ 5 mm. This study aims to determine the effectiveness of chlorhexidine compared to other local antimicrobials in periodontitis. Searches were conducted using the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines. Meta-analysis was performed on studies that met inclusion criteria after risk of bias assessment. Meta-analysis between chlorhexidine chips and other antimicrobials showed a mean difference in probing depth after one month of 0.58 mm (p < 0.00001) whereas after three months the mean difference in probing depth was 0.50 mm (p = 0.001), index plaque 0.01 (p = 0.94) and gingival index - 0.11 mm (p = 0.02). Between chlorhexidine gel and other antimicrobials showed a mean difference in probing depth of 0.40 mm (p = 0.30), plaque index of 0.20 mm (p = 0.0008) and gingival index of -0.04 mm (p = 0.83) after one month. Chlorhexidine chips were more effective on the gingival index than other antimicrobials after three months. The other antimicrobials were more effective than chlorhexidine chips on probing depth after one and three months, and than chlorhexidine gels on plaque index after one month.