Correction: Bone marrow cell extract promotes the regeneration of irradiated bone.

[This corrects the article DOI: 10.1371/journal.pone.0178060.].

Bone marrow cell extract promotes the regeneration of irradiated bone.

Mandibular osteoradionecrosis is a severe side effect of radiotherapy after the treatment of squamous cell carcinomas of the upper aerodigestive tract. As an alternative to its treatment by micro-anastomosed free-flaps, preclinical tissular engineering studies have been developed. Total bone marrow (TBM) associated with biphasic calcium phosphate (BCP) significantly enhanced bone formation in irradiated bone. One mechanism, explaining how bone marrow cells can help regenerate tissues like this, is the paracrine effect. The bone marrow cell extract (BMCE) makes use of this paracrine mechanism by keeping only the soluble factors such as growth factors and cytokines. It has provided significant results in repairing various tissues, but has not yet been studied in irradiated bone reconstruction. The purpose of this study was to evaluate the effect of BMCE via an intraosseous or intravenous delivery, with a calcium phosphate scaffold, in irradiated bone reconstruction. Twenty rats were irradiated on their hind limbs with a single 80-Gy dose. Three weeks later, surgery was performed to create osseous defects. The intraosseous group (n = 12) studied the effect of BMCE in situ, with six combinations (empty defect, BCP, TBM, BCP-TBM, lysate only, BCP-lysate). After four different combinations of implantation (empty defect, BCP, TBM, BCP-TBM), the intravenous group (n = 8) received four intravenous injections of BMCE for 2 weeks. Five weeks after implantation, samples were explanted for histological and scanning electron microscopy analysis. Lysate immunogenicity was studied with various mixed lymphocyte reactions. Intravenous injections of BMCE led to a significant new bone formation compared to the intraosseous group. The BCP-TBM mixture remained the most effective in the intraosseous group. However, intravenous injections were more effective, with TBM placed in the defect, with or without biomaterials. Histologically, highly cellularized bone marrow was observed in the defects after intravenous injections, and not after an in situ use of the lysate. The mixed lymphocyte reactions did not show any proliferation after 3, 5, or 7 days of lysate incubation with lymphocytes from another species. This study evaluated the role of BMCE in irradiated bone reconstruction. There were significant results arguing in favor of BMCE intravenous injections. This could open new perspectives to irradiated bone reconstruction.

Vascular Supply of the Auricle: Anatomical Study and Applications to External Ear Reconstruction.

BACKGROUND: Reliable reconstructive flaps require convenient vascular supply. Thus, precise description of the vascular patterns of external ear is not completely elucidated. OBJECTIVE: This anatomical study aims to provide comprehensive data of the arterial network of the auricular region, anastomosis, and patterns of arterial dependence regarding external ear subunits. MATERIALS AND METHODS: After dyed latex injections in the external carotid artery, eleven auricles have been carefully dissected to examine the vascular network of the auricular region. RESULTS: In all cases, the posterior auricular artery (PAA) supplied the cranial side of the auricle, as well as the concha on the lateral side through consistent perforating branches. The superficial temporal artery (STA) network supplied the upper third of the lateral aspect of the auricle. The authors' dissections showed a clear dominance of the PAA supply. However, the two arteries consistently developed anastomoses particularly in the cranial upper third of the auricle. CONCLUSION: Consistent branches and anastomoses between the PAA and the STA network provide reliable pedicles for auricular and facial reconstruction.