Akkermansia muciniphila promotes type H vessel formation and bone fracture healing by reducing gut permeability and inflammation

Improving revascularization is one of the major measures in fracture treatment. Moderate local inflammation triggers angiogenesis, whereas systemic inflammation hampers angiogenesis. Previous studies showed that Akkermansia muciniphila, a gut probiotic, ameliorates systemic inflammation by tightening the intestinal barrier. In this study, fractured mice intragastrically administrated with A. muciniphila were found to display better fracture healing than mice treated with vehicle. Notably, more preosteclasts positive for platelet-derived growth factor-BB (PDGF-BB) were induced by A. muciniphila at 2 weeks post fracture, coinciding with increased formation of type H vessels, a specific vessel subtype that couples angiogenesis and osteogenesis, and can be stimulated by PDGF-BB. Moreover, A. muciniphila treatment significantly reduced gut permeability and inflammation at the early stage. Dextran sulfate sodium (DSS) was used to disrupt the gut barrier to determine its role in fracture healing and whether A. muciniphila still can stimulate bone fracture healing. As expected, A. muciniphila evidently improved gut barrier, reduced inflammation and restored the impaired bone healing and angiogenesis in DSS-treated mice. Our results suggest that A. muciniphila reduces intestinal permeability and alleviates inflammation, which probably induces more PDGF-BB+ preosteoclasts and type H vessel formation in callus, thereby promoting fracture healing. This study provides the evidence for the involvement of type H vessels in fracture healing and suggests the potential of A. muciniphila as a promising strategy for bone healing.This article has an associated First Person interview with the first author of the paper.

[Efficacy and safety of endonasal phototherapy in the treatment of adult allergic rhinitis: A Meta-analysis]

Objective:To perform a systematic review of the efficacy and safety of endonasal phototherapy in the treatment of AR, and to provide evidence of evidence-based medicine for clinical application. Method:Databases were from PubMed, Embase, Cochrane Library, Chinese Academic Journal Full-text Database (CNKI) and Wanfang database. A randomized controlled trial (RCT) or clinical study literature on intranasal phototherapy for adult AR is available, and the deadline is March 2017. Based on the literature inclusion and exclusion criteria, the related literatures were selected and the quality was evaluated by using the Cochrane inclusion bias assessment table. Meta-analysis was performed with Revman 5.3 software. For continuous outcomes, the weighted mean difference (WMD) and its 95% confidence intervals (CI) were calculated, forest maps and funnel plots were drew. For uncontinuous outcomes, the odds ratio (OR) and its 95%CI were calculated, and forest maps and funnel plots were drew. The efficacy included total nasal symptom scores (TNSS), rhinoconjunctivitis quality of life questionnaire (RQLQ) and palate itching scores, and the safety was assessed by incidence rate of severe drying and mild drying of nasal mucosa. Result:A total of 12 articles were selected, including 5 RCT and 7 clinical studies, and there were 615 adult AR patients. The Meta-analysis shows that endonasal phototherapy significantly reduced the TNSS, RQLQ and palate itching scores, the incidence rate of mild drying of nasal mucosa was higher in comparison with pretreated values, and the difference was statistically significant (P<0.05). The rate of severe drying of nasal mucosa was higher, but the difference was not statistically significant (P>0.05). It also shows that endonasal phototherapy significantly reduced the TNSS, RQLQ and palate itching scores, and the rate of mild drying of nasal mucosa was higher in comparison with placebo and antihistamines groups, and the difference was statistically significant. The rate of severe drying of nasal mucosa was higher, but the difference was not statistically significant. Conclusion:Endonasal phototherapy can improve the symptoms of TNSS, RQLQ and palate itching score in patients, and the safety is also confirmed.Patients who are not satisfied with symptom relief may choose to use it.