Modulation of opportunistic species Corynebacterium diphtheriae, Haemophilus parainfluenzae, Moraxella catarrhalis, Prevotella denticola, Prevotella melaninogenica, Rothia dentocariosa, Staphylococcus aureus and Streptococcus pseudopneumoniae by intranasal administration of Streptococcus salivarius 24SMBc and Streptococcus oralis 89a combination in healthy subjects.

OBJECTIVE: Probiotics S. salivarius 24SMBc and S. oralis 89a comprised in the nasal spray Rinogermina are known to exert inhibition of harmful pathogens and ameliorate the outcome of patients with chronic upper airways infections. In this study, for the first time, the effect of this formulation on the modulation of the microflora of healthy subjects was evaluated, with particular interest on pathobionts and pathogens present. PATIENTS AND METHODS: Metagenomic identification and quantification of bacterial abundances in healthy subjects were carried out by means of Ion Torrent Personal Machine. In particular, nasal swabs were sampled one, two and four weeks after seven days of treatment with Rinogermina. RESULTS: The modulation of the abundance of pathobionts and pathogenic species (i.e., Corynebacterium diphtheriae, Haemophilus parainfluenzae, Moraxella catarrhalis, Prevotella denticola, Prevotella melaninogenica, Rothia dentocariosa, Staphylococcus aureus and Streptococcus pseudopneumoniae) was characterized and a significant temporary decrease in their presence was identified. CONCLUSIONS: The beneficial effects of S. salivarius 24SMBc and S. oralis 89a nasal intake was assessed but seemed to be restricted in specific temporal windows. Thus it would be interesting to evaluate also this positive impact of longer administration of this probiotic formulation.

A new strategy for the decellularisation of large equine tendons as biocompatible tendon substitutes.

Tendon ruptures and/or large losses remain to be a great clinical challenge and often require full replacement of the damaged tissue. The use of auto- and allografts or engineered scaffolds is an established approach to restore severe tendon injuries. However, these grafts are commonly related to scarce biocompatibility, site morbidity, chronic inflammation and poor biomechanical properties. Recently, the decellularisation techniques of allo- or xenografts using specific detergents have been studied and have been found to generate biocompatible substitutes that resemble the native tissue. This study aims to identify a novel decellularisation protocol for large equine tendons that would produce an extracellular matrix scaffold suitable for the regeneration of injured tendons in humans. Specifically, equine tendons were treated either with tri (n-butyl) phosphate alone, or associated to multiple concentrations of peracetic acid (1, 3 and 5 %), which has never before been tested in vitro.Samples were then analysed by histology and with biochemical, biomechanical, and cytotoxicity tests. The best decellularisation protocol, resulting from these examinations, was selected and the chosen scaffold was re-seeded with murine fibroblasts. Resulting grafts were tested for cell viability, histologic analysis, DNA and collagen content. The results identified 1 % tri (n-butyl) phosphate combined with 3 % peracetic acid as the most suitable decellularised matrix in terms of biochemical and biomechanical properties. Moreover, the non-cytotoxic nature of the decellularised matrix allowed for good fibroblast reseeding, thus demonstrating a biocompatible matrix that will be suitable for tendon tissue engineering and hopefully as substitutes in severe tendon damages.

In Vivo Bone Formation Within Engineered Hydroxyapatite Scaffolds in a Sheep Model.

Large bone defects still represent a major burden in orthopedics, requiring bone-graft implantation to promote the bone repair. Along with autografts that currently represent the gold standard for complicated fracture repair, the bone tissue engineering offers a promising alternative strategy combining bone-graft substitutes with osteoprogenitor cells able to support the bone tissue ingrowth within the implant. Hence, the optimization of cell loading and distribution within osteoconductive scaffolds is mandatory to support a successful bone formation within the scaffold pores. With this purpose, we engineered constructs by seeding and culturing autologous, osteodifferentiated bone marrow mesenchymal stem cells within hydroxyapatite (HA)-based grafts by means of a perfusion bioreactor to enhance the in vivo implant-bone osseointegration in an ovine model. Specifically, we compared the engineered constructs in two different anatomical bone sites, tibia, and femur, compared with cell-free or static cell-loaded scaffolds. After 2 and 4 months, the bone formation and the scaffold osseointegration were assessed by micro-CT and histological analyses. The results demonstrated the capability of the acellular HA-based grafts to determine an implant-bone osseointegration similar to that of statically or dynamically cultured grafts. Our study demonstrated that the tibia is characterized by a lower bone repair capability compared to femur, in which the contribution of transplanted cells is not crucial to enhance the bone-implant osseointegration. Indeed, only in tibia, the dynamic cell-loaded implants performed slightly better than the cell-free or static cell-loaded grafts, indicating that this is a valid approach to sustain the bone deposition and osseointegration in disadvantaged anatomical sites.