Combining regenerative medicine strategies to provide durable reconstructive options: auricular cartilage tissue engineering

Recent advances in regenerative medicine place us in a unique position to improve the quality of engineered tissue. We use auricular cartilage as an exemplar to illustrate how the use of tissue-specific adult stem cells, assembly through additive manufacturing and improved understanding of postnatal tissue maturation will allow us to more accurately replicate native tissue anisotropy. This review highlights the limitations of autologous auricular reconstruction, including donor site morbidity, technical considerations and long-term complications. Current tissue-engineered auricular constructs implanted into immune-competent animal models have been observed to undergo inflammation, fibrosis, foreign body reaction, calcification and degradation. Combining biomimetic regenerative medicine strategies will allow us to improve tissue-engineered auricular cartilage with respect to biochemical composition and functionality, as well as microstructural organization and overall shape. Creating functional and durable tissue has the potential to shift the paradigm in reconstructive surgery by obviating the need for donor sites

효과적 연부조직 재건을 위한 동종지방기질 및 수산화마그네슘 함유 폴리(락틱-코-글리콜산) 미립구를 이용한 지방이식술

학위논문(박사) -- 서울대학교대학원 : 의과대학 의학과, 2022. 8. 이정찬.Autologous fat grafting is one of the most common procedures used in plastic surgery to correct soft tissue deficiency or depression deformity. However, its clinical outcomes are often suboptimal, and lack of metabolic and architectural support at recipient sites affects fat graft survival leading to complications such as cyst formation and calcification. Extracellular matrix (ECM)-based scaffolds, such as allograft adipose matrix (AAM) and poly (lactic-co-glycolic acid) (PLGA), have shown exceptional clinical promise as regenerative scaffolds. AAM is composed of the extracellular matrices of adipose tissue through decellularization. Additionally, PLGA is one of the most commonly used biopolymers owing to its biodegradability for tissue regenerations. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive to improve biocompatibility. Magnesium hydroxide (MH) could neutralize the acidic microenvironment induced by the acidic decomposed products of PLGA, thereby suppressing undesirable inflammatory reactions. We attempted to combine fat graft with injectable regenerative scaffolds: natural (AAM) and synthetic (PLGA/MH microspheres). We investigated the volume changes and viability of injected fat graft in relation to the effects of biomaterials. In this study, a comparison of the volume retention effect and angiogenic ability in vivo between autologous fat grafting, injectable natural (AAM), and synthetic (PLGA/MH microsphere) biomaterials will provide a reasonable basis for fat grafting. And by using PLGA/MH microsphere, we could overcome the disadvantages of conventional PLGA scaffolds and effectively improve fat retention rate with complex biological functions.1. Introduction 1 2. Materials and Methods 5 Materials 5 Fabrication of the PLGA microspheres 5 Scaffold characterization and in vitro degradation test 6 Cell cytotoxicity assay 6 In vitro wound healing assay 7 Quantitative real-time PCR 7 Fat preparation 8 Allograft adipose matrix preparation 8 Animal study 8 Histological analysis 9 Statistical analysis 10 3. Results and Discussion 10 Scaffold fabrication and characterization 10 In vitro biocompatibility and anti-inflammatory effect of scaffold 11 Wound healing and angiogenic effect of the scaffold 14 Volume retention effect of the scaffold for fat grafting survival 15 In vivo evaluation of the scaffold for fat grafting survival 17 4. Conclusions 19 References 21 Abstract 26 Acknowledgements 28박

From bench to bedside – current clinical and translational challenges in fibula free flap reconstruction

Fibula free flaps (FFF) represent a working horse for different reconstructive scenarios in facial surgery. While FFF were initially established for mandible reconstruction, advancements in planning for microsurgical techniques have paved the way toward a broader spectrum of indications, including maxillary defects. Essential factors to improve patient outcomes following FFF include minimal donor site morbidity, adequate bone length, and dual blood supply. Yet, persisting clinical and translational challenges hamper the effectiveness of FFF. In the preoperative phase, virtual surgical planning and artificial intelligence tools carry untapped potential, while the intraoperative role of individualized surgical templates and bioprinted prostheses remains to be summarized. Further, the integration of novel flap monitoring technologies into postoperative patient management has been subject to translational and clinical research efforts. Overall, there is a paucity of studies condensing the body of knowledge on emerging technologies and techniques in FFF surgery. Herein, we aim to review current challenges and solution possibilities in FFF. This line of research may serve as a pocket guide on cutting-edge developments and facilitate future targeted research in FFF