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Abstract. In the field of plastic and reconstructive surgery, the loss of organs or tissues caused by diseases or injuries has resulted in challenges, such as donor shortage and immunosuppression. In recent years, with the development of regenerative medicine, the decellularization-recellularization strategy seems to be a promising and attractive method to resolve these difficulties. The decellularized extracellular matrix contains no cells and genetic materials, while retaining the complex ultrastructure, and it can be used as a scaffold for cell seeding and subsequent transplantation, thereby promoting the regeneration of diseased or damaged tissues and organs. This review provided an overview of decellularization-recellularization technique, and mainly concentrated on the application of decellularization-recellularization technique in the field of plastic and reconstructive surgery, including the remodeling of skin, nose, ears, face, and limbs. Finally, we proposed the challenges in and the direction of future development of decellularization-recellularization technique in plastic surgery.

Skeletal muscle regeneration mainly depends on muscle satellite cells; however, these cells are not sufficient for supporting repair and regeneration in volumetric muscle loss (VML), Duchenne muscular dystrophy, and other muscle injuries or muscle diseases. As such, much work has been conducted in recent years to search for myogenic stem cells. Adipose-derived stem cells (ADSCs) have a wide range of sources, rapid growth, and multi-directional differentiation potential, and have become vital candidates for muscle regeneration. Multiple factors influence the myogenic differentiation capacity of ADSCs. This paper reviews the regulatory aspects and possible factors that have been identified in recent years to affect myogenic differentiation of ADSCs. Based on these factors, gene editing, and perfusion concepts, a method was proposed to achieve maximal differentiation efficiency of ADSCs. This study focused on the application of ADSCs in muscle regeneration and disease. Based on the importance of myogenic differentiation of ADSCs for the repair and regeneration of muscle damage, this study provides a basis for future research surrounding the efficient induction of myogenic differentiation of ADSCs in vitro.

Background: Massage is generally believed to be a simple and effective method for preventing necrosis when intravascular injection emboli are suspected. Due to its good dispersive properties, polymethyl methacrylate (PMMA) was used as the test filler. The main purpose of this study was to observe whether local massage as a simple remedial measure can promote the diffusion of filler and reduce the necrosis rate for intra-arterial embolism. Methods: Rabbit ears with the central ear artery (CEA) main trunk totally or segmentally obstructed 5 ​min after PMMA injection were studied. In order to simulate the massage effect of the fingers, the massage group was treated with a small beauty massage bar with a fixed vibration frequency along the direction of the blood flow. CEA blood flow and skin lesions were also analyzed. Results: The baseline data were similar between the control and massage groups. Compared to the control group, the recanalization rate of the CEA trunk in the treatment group increased significantly after massage. However, there was no significant difference in the visible rate of transparent embolus on the 1st day after treatment, nor in the necrosis degree or area of soft tissue damage on the 7th day after treatment. Further analysis showed that massage tended to have a positive effect on segmentally obstructed cases at 5 ​min after injection but a negative effect on totally obstructed ears at 5 ​min. Conclusion: Local massage cannot reduce the complications of tissue necrosis after intra-arterial PMMA injection. Prevention is key to reducing complications.

An increasing number of researchers have demonstrated that poloxamer 188 (P188) can be used as a pharmaceutical excipient for clinical applications. Its membrane-sealing effects and inherent biological activities make it an extremely promising agent for plastic surgery. In this review, we summarize the positive roles of P188 in autologous fat grafting, wound healing, and cartilage transplantation. These roles include improving the survival rate of fat grafts and chondrocytes, stimulating the metabolic activity of adipocytes, promoting wound healing, and contributing to cartilage formation. Although further research is still needed, it is clear that P188 has great potential and application value in the field of plastic surgery.

Extracellular vesicles (EVs) are specific subcellular vesicles released by cells under various environmental conditions. Tumescent liposuction is a commonly used procedure in plastic surgery practice. In the present study, we aimed to extract EVs derived from lipoaspirate fluid (LF-EVs) and characterize them using transmission electron microscopy, nanoparticle tracking analysis, and western blotting. The global profiles of proteins and microRNAs from LF-EVs were identified, strongly suggesting a potential regulatory function of LF-EVs. In addition, we investigated the effects and mechanisms of LF-EVs on fat graft survival. Cell functional tests showed that LF-EVs promoted the proliferation, migration, and tube structure formation of human umbilical vein endothelial cells. LF-EVs also promoted the adipogenic differentiation of adipose tissue-derived stem cells. The results of animal experiments showed that the average weights of fat grafts in the LF-EVs-treated group were significantly higher than those in the control group. Histologically, there was less fibrosis, fewer cysts, and increased fat tissue survival in the LF-EVs group. Further investigations of angiogenic and adipogenic factors revealed that LF-EVs also promoted angiogenesis and exerted a pro-adipogenic effect in vivo. Our findings will help to elucidate the functions of LF-EVs and provide a reference dataset for future translational studies.

Abstract Background A refractory wound is a typical complication of diabetes and is a common outcome after surgery. Current approaches have difficulty in improving wound healing. Recently, non-expanded stromal vascular fraction (SVF), which is derived from mature fat, has opened up new directions for the treatment of refractory wound healing. The aim of the current study is to systematically investigate the impact of SVF on wound healing, including the rate and characteristics of wound healing, ability of fibroblasts to migrate, and blood transport reconstruction, with a special emphasis on their precise molecular mechanisms. Methods SVF was isolated by digestion, followed by filtration and centrifugation, and then validated by immunocytochemistry, a MTS proliferation assay and multilineage potential analysis. A wound model was generated by creating 6-mm-diameter wounds, which include a full skin defect, on the backs of streptozocin-induced hyperglycemic mice. SVF or human adipose-derived stem cell (hADSC) suspensions were subcutaneously injected, and the wounds were characterized over a 9-day period by photography and measurements. A scratch test was used to determine whether changes in the migratory ability of fibroblasts occurred after co-culture with hADSCs. Angiogenesis was observed with human umbilical vein endothelial cells. mRNA from fibroblasts, endotheliocyte, and skin tissue were sequenced by high-throughput RNAseq, and differentially expressed genes, and pathways, potentially regulated by SVF or hADSCs were bioinformatically analyzed. Results Our data show that hADSCs have multiple characteristics of MSC. SVF and hADSCs significantly improved wound healing in hyperglycemic mice. hADSCs improve the migratory ability of fibroblasts and capillary structure formation in HUVECs. SVF promotes wound healing by focusing on angiogenesis and matrix remodeling. Conclusions Both SVF and hADSCs improve the function of fibroblast and endothelial cells, regulate gene expression, and promote skin healing. Various mechanisms likely are involved, including migration of fibroblasts, tubulogenesis of endothelial cells through regulation of cell adhesion, and cytokine pathways.

Keloids exhibit metabolic reprogramming including enhanced glycolysis and attenuated oxidative phosphorylation. Hypoxia induces a series of protective responses in mammalian cells. However, the metabolic phenotype of keloid fibroblasts under hypoxic conditions remains to be elucidated. The present study aimed to investigate glycolytic activity, mitochondrial function and morphology, and the HIF1α and PI3K/AKT signaling pathways in keloid fibroblasts (KFB) under hypoxic conditions. Our results showed that hypoxia promoted proliferation, migration invasion and collagen synthesis and inhibited apoptosis in KFB. The mRNA levels, protein expressions and enzyme activities of glycolytic enzymes in KFB were higher than those in normal skin fibroblasts (NFB) under normoxia. Moreover, hypoxia remarkedly upregulated glycolysis in KFB. Decreased activities of mitochondrial complexes and abnormal mitochondria were detected in KFB under normoxic conditions and the damage was aggravated by hypoxia. An intracellular metabolic profile assay suggested hypoxia increased glycolytic parameters except glycolytic reserve but inhibited the key parameters of mitochondrial function apart from H+ leak. Protein levels of HIF1α and phosphorylation levels of the PI3K/AKT signaling pathway were upregulated in the context of 3% oxygen. Enhanced total reactive oxygen species (ROS), mitochondrial ROS (mitoROS) and antioxidant activities of KFB were observed in response to hypoxia. Additionally, autophagy was induced by hypoxia. Our data collectively demonstrated potentiated glycolysis and attenuated mitochondrial function under hypoxia, indicating that altered glucose metabolism regulated by hypoxia could be a therapeutic target for keloids.

Periostin, a secreted extracellular matrix protein, is highly expressed in wound healing and in various types of human cancer and is involved in angiogenesis. Keloids, considered dermal benign tumors, are granulomatous lesions characterized by capillary proliferation. However, the underlying regulatory mechanism of angiogenesis in keloids remains to be elucidated. The present study aimed to examine the effect of periostin on angiogenesis in keloids. The expression of periostin was upregulated and the vessel density was higher in human keloids compared with normal tissue, observed following staining with CD31 and CD105. Periostin demonstrated a markedly positive correlation with blood vessel density, which was assessed using CD31 staining (r=0.711; P<0.01) and a weak correlation was observed using CD105 staining (r=0.251; P<0.01). Conditioned medium from keloid fibroblasts (KFs) promoted the migration and tube formation of human umbilical vein endothelial cells (HUVECs) compared with normal fibroblasts and this effect may have been abrogated by the short hairpin RNA knockdown of periostin. Treatment with recombinant human periostin promoted the migration and tube formation of HUVECs by activating the extracellular signal-regulated kinase 1/2 and focal adhesion kinase signaling pathway. In addition, periostin increased the secretion of vascular endothelial growth factor and angiopoietin-1 in the KFs. In conclusion, these data suggested that upregulation in the level of periostin may promote angiogenesis directly and indirectly in keloids and may be a key factor in keloid development. Periostin may, therefore, be a promising therapeutic target in the treatment of keloids and other angioproliferative diseases. [ABSTRACT FROM AUTHOR]