Low virulent bacterial-induced nonunions: Antibiotic and cell-based preventive strategies in animal models

Global Congress on Tissue Engineering, Regenerative & Precision Medicine

December 1-2, 2016 | San Antonio, USA

Arianna Barbara Lovati

IRCCS Galeazzi Orthopedic Institute, Italy

Posters & Accepted Abstracts: J Tissue Sci Eng

Abstract :

Staphylococcus epidermidis is responsible for orthopedic biofilm-related infections and fracture healing delay and/or nonunion establishment. Rat models of subclinical, acute and chronic S. epidermidis-induced nonunions were recently created to investigate innovative strategies to prevent low virulent bacterial infections. Femoral fractures were synthesized with stainless-steel plates and injected with increasing bacterial loads to point out the dose-dependent effect between the bacterial inoculum and nonunion rate. The bacterial load leading to acute signs of osteomyelitis was chosen to test locally and systemically the efficacy of vancomycin (l-VANC and s-VANC) or allogeneic mesenchymal stem cells in the prevention of the pathology (l-MSCs and s-MSCs). The host response to treatments was assessed by blood analyses, plasma pro-inflammatory cytokines, as well as by micro-CT, histological and microbiological analyses. Half of the s-MSCs rats died closely to the systemic cell injection. In s-VANC and l-VANC groups, imaging analysis showed a good bony bridging, histologically confirmed by a mature bone development along with a bacterial count under the limits of detection. The l-MSCs group showed a poor bony bridging consisting in inflammatory and fibrovascular tissue. These data were consistent with the neutrophil counts and elevated plasma levels of IL-1�±, IL-1�² and TNF-�±. Our results suggest that the infected-nonunion establishment can be prevented by the synergic use of systemic and local vancomycin injection. Otherwise, cell therapies cannot be considered usable due to the high risk occurred in cell systemic injection and deeper investigations are required to better identify the immunomodulatory role of MSCs in the presence of bacteria.

Biography :

Email: arianna.lovati@grupposandonato.it