Fibroblast Growth Factor-Impregnated Collagen-Gelatin Sponge Improves Keratinocyte Sheet Survival.

Commercially available cultured epithelial keratinocyte sheets (KSs) have played an essential role in wound healing over the past four decades. Despite the initial uptake by the dermal elements, the survival rate of KS on the dermis-like tissue generated by conventional artificial dermis (AD) is low, making this method unsuitable for standard treatments. Therefore, an innovative AD such as collagen-gelatin sponge (CGS) that maintains the release of human recombinant basic fibroblast growth factor (bFGF) may promote wound healing. In this study, we examined whether combination therapy with KSs and CGS with bFGF (bFGF-CGS) could enhance KS survival by heterologous grafting by transplantation of human-derived KSs in an athymic nude rat wound model of staged skin reconstruction. The CGSs were implanted into skin defect wounds on athymic nude rats, which were then divided into two experimental groups: the bFGF group (CGSs containing bFGF, n = 8) and the control group (CGSs with saline, n = 8). Two weeks after implantation, human epithelial cell-derived KSs were grafted onto the dermis-like tissue, followed by assessment of the survival and morphology at 1 week later using digital imaging, histology (hematoxylin and eosin and Masson's trichrome staining), immunohistology (von Willebrand factor), immunohistochemistry (cytokeratin 1-5-6, Ki-67), and immunofluorescence (collagen IV, pan-cytokeratins) analyses. The bFGF group showed a significantly higher KS survival area (86 ± 58 mm2 vs. 32 ± 22 mm2; p < 0.05) and increased epidermal thickness (158 ± 66 µm vs. 86 ± 40 µm; p < 0.05) compared with the control group, along with higher dermis-like tissue regeneration, neovascularization, epidermal maturation, and basement membrane development. These results indicate that the survival rate of KSs in the dermis-like tissue formed by bFGF-CGS was significantly increased. Therefore, combination treatment of bFGF-CGS and KSs shows potential for full-thickness skin defect reconstruction in clinical situations. Impact statement This study highlights how using a combination of cultures, keratinocyte sheets, and collagen-gelatin sponge containing basic fibroblast growth factors can significantly improve cell survival in athymic nude rats with staged skin reconstruction. Our study makes a significant contribution to the literature because it highlights a novel and improved strategy for treating a very common condition such as skin wounds arising from many conditions. Clinical translation of this study may be useful for treating skin wounds.

Facial nerve regeneration with bioabsorbable collagen conduits filled with collagen filaments: An experimental study.

INTRODUCTION: A bioabsorbable collagen conduit (Renerve™) filled with collagen filaments is currently approved as an artificial nerve conduit in Japan and is mainly used for connecting and repairing peripheral nerves after traumatic nerve injury. However, there are few reports on its applications for reconstructing and repairing the facial nerve. The present study evaluated the efficacy of the conduit on promoting nerve regeneration in a murine model with a nerve defect at the buccal branch of the facial nerve. METHODS: Under inhalational anesthesia and microscopic guidance, the buccal branch of the left facial nerve in an 8-week-old Lewis rat was exposed, and a 7 mm gap was created in the nerve. The gap was then connected with either the nerve conduits (NC group) or an autologous nerve graft (the autograft group). At 13 weeks after the procedure, we compared the histological and physiological regenerations in the both groups. RESULTS: We found compound muscle action potential amplitude is significantly larger in the autograft group (2.8 ± 1.4 mV) than in NC group (1.3 ± 0.5 mV) (p < 0.05). The number of myelinated fibers of the autograft group was higher (3634 ± 1645) than that of NC group (1112 ± 490) (p < 0.01). The fiber diameter of the autograft group (4.8 ± 1.9 µm) was larger than that of NC group (3.8 ± 1.4 µm) (p < 0.05). The myelin thickness of the autograft group was thicker than that of NC group (0.6 ± 0.3 µm vs. 0.4 ± 0.1 µm) (p < 0.05). G-ratio of the autograft group (0.74 ± 0.19) was lower than that of NC group (0.79 ± 0.10) (p < 0.05). CONCLUSION: This study demonstrated the efficacy of collagen nerve conduit for facial nerve reconstruction following nerve injury. However, the effectiveness of the conduit on the promotion of nerve regeneration was inferior to that of the autograft.

Superficial Temporal Artery Pseudoaneurysm following Midface Thread-lift.

Facial thread-lifting has been popular because of its ease and safety with short down time. However, many physicians perform the procedure in cosmetic clinics, which can result in several complications. This report describes the surgical treatment of iatrogenic superficial temporal artery pseudoaneurysm (STAP) following thread-lifting. A 27-year-old man developed a painless, pulsating soft mass in the pre-auricular region after undergoing a thread-lift in a private cosmetic clinic 3 months before being referred to the authors' hospital. The mass was diagnosed as a STAP, using magnetic resonance imaging. The pseudoaneurysm was resected completely, and the superficial temporal artery was microsurgically reconstructed. Although there are some surgical procedures for treating STAP, such as surgical resection and embolization, the former is considered the first choice. Physicians should be trained before performing thread-lifting and must know the possibility of an iatrogenic STAP appearing after the procedure and the face and neck anatomy to prevent complications.

Reply to Correspondence: Response to a case report: idiopathic hypereosinophilic syndrome in remission with benralizumab treatment after relapse with mepolizumab.

See related Letter.

Idiopathic hypereosinophilic syndrome in remission with benralizumab treatment after relapse with mepolizumab.

We report a patient with idiopathic hypereosinophilic syndrome (I-HES) who achieved remission with benralizumab after relapsing on mepolizumab. An 83-year-old man was admitted to Showa General Hospital after presenting with hypoxaemia and multiple erythematous lesions. He showed a marked increase in blood eosinophil count. Skin biopsy revealed an invasion of eosinophils in the dermis. He was diagnosed with I-HES. He was commenced on prednisolone 40 mg/day with a plan to wean this over time after pulse steroid therapy for three days. Mepolizumab was added when the prednisolone dose was 25 mg/day. Unfortunately, at a prednisolone dose of 5 mg/day, there was evidence of disease progression and the patient was switched to benralizumab. Prednisolone was tapered again and, finally, the patient was in remission. Benralizumab targets interleukin (IL)-5R and induces antibody-dependent cell-mediated cytotoxicity, thereby reducing the eosinophil counts in the tissue. This can be attributed to the therapeutic efficacy against I-HES. We believe this report may help develop novel therapeutic strategies for I-HES.