Clinical Outcomes of Utilizing a "W"-shaped Incision in the Management of Forehead Skin Thickening Induced by Hypertrophic Osteoarthropathy.

BACKGROUND: Hypertrophic osteoarthropathy (HOA) is a rare and intricate hereditary disease. The appearance and functional deformity of the forehead caused by thickened folds are the main clinical manifestations of patients with hypertrophic osteoarthropathy. The cause of this disease is still unknown. Currently, surgical treatment has become one of the best strategies, mainly for improving the appearance of the forehead. There has been no literature report on the use of "W"-shaped skin flap resection for thickened forehead skin in patients with hypertrophic osteoarthropathy. METHODS: All cases of hypertrophic osteoarthropathy in our department in the last 7 years, and previous literature on hypertrophic osteoarthropathy, were reviewed. RESULTS: A total of 5 cases of hypertrophic osteoarthropathy in our department (mean age 21 years, all male patients) were reviewed. All patients underwent open surgery to remove the thickened skin on the forehead or the wrinkles and gyrus-shaped scalp. The jagged skin tissue was removed (8-9) cm × (1-2.5) cm × 0.5 cm. The folds and thickness of the frontal skin of the patients were greatly improved after the operation. Patient satisfaction with the treatment outcomes was unanimous. However, one case experienced a postoperative wound infection during follow-up. The utilization of the "W"-shaped excision technique allowed for the maximal removal of excessively diseased tissue, thereby facilitating a smoother resolution of the depression. CONCLUSIONS: A total of 5 cases of hypertrophic osteoarthropathy were treated in our department, and all of them underwent frontal skin "W"-shaped excision, which was safe, feasible, and practical, and the postoperative results were satisfactory. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exosomal Lnc NEAT1 from endothelial cells promote bone regeneration by regulating macrophage polarization via DDX3X/NLRP3 axis.

BACKGROUND: Bone regeneration is a complex procedure that involves an interaction between osteogenesis and inflammation. Macrophages in the microenvironment are instrumental in bone metabolism. Amount evidence have revealed that exosomes transmitting lncRNA is crucial nanocarriers for cellular interactions in various biotic procedures, especially, osteogenesis. However, the underlying mechanisms of the regulatory relationship between the exosomes and macrophages are awaiting clarification. In the present time study, we aimed to explore the roles of human umbilical vein endothelial cells (HUVECs)-derived exosomes carrying nuclear enrichment enriched transcript 1 (NEAT1) in the osteogenesis mediated by M2 polarized macrophages and elucidate the underlying mechanisms. RESULTS: We demonstrated HUVECs-derived exosomes expressing NEAT1 significantly enhanced M2 polarization and attenuated LPS-induced inflammation in vitro. Besides, the conditioned medium from macrophages induced by the exosomes indirectly facilitated the migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Mechanically, Exos carrying NEAT1 decreased remarkably both expression of dead-box helicase 3X-linked (DDX3X) and nod-like receptor protein 3 (NLRP3). The level of NLRP3 protein increased significantly after RAW264.7 cells transfected with DDX3X overexpression plasmid. Additionally, the knockdown of NEAT1 in exosomes partially counteracted the aforementioned effect of Exos. The results of air pouch rat model demonstrated that HUVECs-derived exosomes increased anti-inflammatory cytokines (IL-10) and decreased pro-inflammatory cytokines (IL-1ß and IL-6) significantly in vivo, contributing to amelioration of LPS-induced inflammation. Afterwards, we further confirmed that the HUVECs-derived exosomes encapsulated in alginate/gelatin methacrylate (GelMA) interpenetrating polymer network (IPN) hydrogels could promote the bone regeneration, facilitate the angiogenesis, increase the infiltration of M2 polarized macrophages as well as decrease NLRP3 expression in the rat calvarial defect model. CONCLUSIONS: HUVECs-derived exosomes enable transmitting NEAT1 to alleviate inflammation by inducing M2 polarization of macrophages through DDX3X/NLRP3 regulatory axis, which finally contributes to osteogenesis with the aid of alginate/GelMA IPN hydrogels in vivo. Thus, our study provides insights in bone healing with the aid of HUVECs-derived exosomes-encapsulated composite hydrogels, which exhibited potential towards the use of bone tissue engineering in the foreseeable future.

Rare Recurrent Giant Frontal Osteoma With Skin Multiple Keratinous Cysts and Multinucleated Giant Cell Granulomas.

BACKGROUND: Osteoma is the most common benign tumor of the craniomaxillofacial region. Its etiology remains unclear, and the computed tomography and histopathologic examination contribute to its diagnosis. There are very rare reports of recurrence and malignant transformation after surgical resection. Furthermore, giant frontal osteomas that occurred repeatedly and were accompanied by skin multiple keratinous cysts and multinucleated giant cell granulomas have not been reported in previous literature. METHODS: The previous cases of recurrent frontal osteoma in the literature and all cases of frontal osteoma in our department in the last 5 years were reviewed. RESULTS: A total of 17 cases of frontal osteoma (mean age 40 y, all female) were reviewed in our department. All patients underwent open surgery to remove the frontal osteoma, and no evidence of complications was found during postoperative follow-up. Two patients underwent 2 or more operations due to the recurrence of osteoma. CONCLUSIONS: Two cases of recurrent giant frontal osteoma were reviewed emphatically in this study, including 1 case of giant frontal osteoma with skin multiple keratinous cysts and multinucleated giant cell granulomas. As far as we know, this is the first giant frontal osteoma that occurred repeatedly and was accompanied by skin multiple keratinous cysts and multinucleated giant cell granulomas.

Identification and validation of a prognostic model for melanoma patients with 9 ferroptosis-related gene signature.

BACKGROUND: Melanoma is a highly heterogeneous and aggressive cutaneous malignancy. Ferroptosis, a new pathway of cell death depending on the intracellar iron, has been shown to be significantly associated with apoptosis of a number of tumors, including melanoma. Nevertheless, the relationship between ferroptosis-related genes (FRGs) and the melanoma patients' prognosis needs to be explored. METHODS: Download expression profiles of FRGs and clinical data from The Cancer Genome Atlas (TCGA) database. 70% data were randomly selected from the TCGA database and utilized the univariate Cox analysis and the least absolute shrinkage and selection operator (LASSO) regression model to create a prognostic model, and the remaining 30% was used to validate the predictive power of the model. In addition, GSE65904 and GSE22153 date sets as the verification cohort to testify the predictive ability of the signature. RESULTS: We identified nine FRGs relating with melanoma patients' overall survival (OS) and established a prognostic model based on their expression. During the research, patients were divided into group of high-risk and low-risk according to the results of LASSO regression analysis. Survival time was significantly longer in the low-risk group than that of in the high-risk group (P < 0.001). Enrichment analysis of different risk groups demonstrated that the reasons for the difference were related to immune-related pathways, and the degree of immune cell infiltration in the low-risk group was significantly higher than that in the high-risk group. CONCLUSIONS: The FRG prognostic model we established can predict the prognosis of melanoma patients and may further guide subsequent treatment.

Experimental models for cutaneous hypertrophic scar research.

Human skin wound repair may result in various outcomes with most of them leading to scar formation. Commonly seen in many cutaneous wound healing cases, hypertrophic scars are considered as phenotypes of abnormal wound repair. To prevent the formation of hypertrophic scars, efforts have been made to understand the mechanism of scarring following wound closure. Numerous in vivo and in vitro models have been created to facilitate investigations into cutaneous scarring and the development of antiscarring treatments. To select the best model for a specific study, background knowledge of the current models of hypertrophic scars is necessary. In this review, we describe in vivo and in vitro models for studying hypertrophic scars, as well as the distinct characteristics of these models. The choice of models for a specific study should be based on the characteristics of the model and the goal of the study. In general, in vivo animal models are often used in phenotypical scar formation analysis, development of antiscarring treatment, and functional analyses of individual genes. In contrast, in vitro models are chosen to pathway identification during scar formation as well as in high-throughput analysis in drug development. Besides helping investigators choose the best scarring model for their research, the goal of this review is to provide knowledge for improving the existing models and development of new models. These will contribute to the progress of scarring studies.

Reducing Prominent Mandibular Angle Osteotomy Complications: 10-Year Retrospective Review.

BACKGROUND: Several methods are available for mandibular reduction, and each method is characterized by unique limitations and complications. However, only a few studies have systematically analyzed these complications. This study aimed to investigate the effects of the outcome of performing curved mandibular angle ostectomy and outer cortex grinding in 1-stage operation and to examine the causes of different types and characteristics of complications. METHODS: The subjects consisted of 528 patients who were subjected to curved mandibular angle ostectomy and outer cortex grinding in 1-stage operation through an intraoral approach. Surgical complications and related factors were recorded, and the rates of complication according to surgeons were simultaneously evaluated. RESULTS: The esthetic appearance of all of the patients was significantly improved, and they were satisfied with the results of the operation. The complication rate was 5.87%. No serious complications, such as subcondylar fracture, massive bleeding, permanent facial nerve, or asymmetry, occurred. Some complications, including 4 cases of hematoma, 4 cases of severe swelling, 2 cases of infection, and 1 case of sagging face, were detected. The absolute complication rate among faculty members ranged from 3.5% to 11.1%. CONCLUSIONS: Our protocol is an effective method for mandibular angle osteotomy with very few complications. The rate of complications can be effectively reduced, and some serious complications can be avoided because protective measures are improved.

Expanded Paramedian Forehead Flaps for Nasal Defects: Beyond Aesthetic Subunits.

BACKGROUND: Reconstruction of nasal tip defects presents a significant challenge for plastic surgeons. The form, function, and aesthetic appeal of all nasal subunits must be addressed. The expanded paramedian forehead flap is a good choice for nasal reconstruction, providing similar texture, structure, and skin color, and high reliability. This article discusses the authors' modification of the expanded paramedian forehead flap in reconstructing defects on or around the nasal tip. METHODS: Twenty-two patients with nasal defects located on or around the nasal tip were treated in our institution. Sixteen patients underwent nasal reconstruction with expanded forehead flaps. The other 6 cases with cartilage defect underwent reconstruction with expanded forehead flaps and autogenous rib cartilage grafts. Functional and cosmetic results were assessed by surgeon, patient, and patient's relatives using a scale from 1 to 10. RESULTS: The aesthetic appearance of all patients was significantly improved after surgery. Two cases had mild hyperpigmentation. Two patients considered the flaps too thick. Three cases had minor brow elevation at the donor site. There were no obvious scars at the donor sites. There were no serious complications, such as infection, flap necrosis, deviation, or collapse. CONCLUSIONS: The expanded paramedian forehead flap is a safe and effective method for reconstructing defects located on or around the nasal tip. Moreover, this technique can result in good functional and cosmetic outcomes with very few complications.

Cranioplasty With Mandibular Outer Cortex Bone Grafts.

BACKGROUND: Autologous bone grafts are still the best materials for calvarial reconstruction. In the past, rib, iliac crest, and cranial bone have been used for the reconstruction of the calvarial defects. However, the use of mandibular outer cortex bone graft in calvarial defects reconstruction is poorly reported in literature. This study focused on using the mandibular outer cortex bone grafts for calvarial defects. METHODS: From October 2004 to July 2016, there were a total of 13 patients in this study who underwent cranioplasty with mandibular outer cortex bone grafts to reconstruction calvarial defects. All the patients were followed up for at least 6 months. RESULTS: The majority of the patients were satisfied with the reconstructive outcome. CONCLUSION: The authors consider the mandibular outer cortex bone graft can achieve excellent esthetic results in selected cranioplasty reconstructions.

Clinical Outcomes of Digital Three-Dimensional Hydroxyapatite in Repairing Calvarial Defects.

PURPOSE: The objective of this article is to present the long-term outcomes of digital three-dimensional (3D) hydroxyapatite (HA) implants used for calvarial defects. Porous HA provide good results and have many characteristics, making it suitable for calvarial defect reconstruction. However, using HA may be associated with potentially serious complications, including infection and exposure. The authors used digital 3D HA for cranioplasty for many years and accumulated considerable experience from using it. The authors found that digital 3D HA is an effective method for cranioplasty, showing low complication rate. METHODS: A total of 57 patients underwent calvarial defect reconstruction with 3D HA from June 2009 to August 2016. The follow-up period was 1 to 5 years. RESULTS: Most patients (91.2%) were greatly satisfied with the esthetic outcomes of the surgery. The highest rate of complication was seroma (8.8%). Two patients developed postoperative infections (3.5%). One patient with infections was successfully treated with antibiotic therapy. Another patient was required to undergo an extensive surgical debridement followed by delayed autogenous bone reconstruction. One patient suffered from implant exposure. No hematoma, unexpected fractures, asymmetry, and contour or implant abnormalities occurred. CONCLUSIONS: The digital 3D HA implant was highly biocompatible and durable for the reconstruction of calvarial defects. With appropriate treatment, the proposed method was able to achieve a functional and cosmetic reconstruction with lesser complications.

Chitosan-based biomaterials promote bone regeneration by regulating macrophage fate.

The development of various osteogenic biomaterials has not only promoted the development of bone tissue engineering but also provided more possibilities for bone defect repair. However, most previous studies have focused on the interaction of biomaterials on endogenous or exogenous stem cells involved in the bone regeneration process while neglecting the effect of changes in the immune microenvironment of bone defect sites on bone regeneration after biomaterial implantation into the host. With the development of bone immunology, the role of various immune cells, especially macrophages, in bone regeneration has gradually attracted the attention of researchers. An increasing number of studies have begun to target macrophages to better promote bone regeneration by modulating the fate of macrophages in a spatiotemporally ordered manner to mimic the changes in the immune microenvironment of bone defect sites during the natural repair process of bone tissue. Chitosan is one of the most abundant natural polysaccharides in the world. In recent years, various chitosan-based biomaterials have been widely used in macrophage fate modulation and bone regeneration. In this review, we review the interaction between macrophages and scaffold materials, general information about chitosan, the modulation of macrophage fate by chitosan-based biomaterials, and their application in bone regeneration.

Treatment protocol and surgical techniques for macrogenia.

BACKGROUND: This study focused on the treatment protocol for macrogenia and surgical techniques of the semicircular ostectomy of the mandibular inferior border. METHODS: Seven patients with macrogenia were treated following our treatment protocol including a preoperative assessment (the Delaire analysis), an operative design (three-dimensional reconstruction and simulation), operation techniques (semicircular ostectomy of the mandibular inferior border), and a postoperative evaluation. RESULTS: Our treatment procedure provided an overall harmonizing effect on the lower facial contour. All 7 patients were satisfied with their aesthetic results. A few complications such as numbness and submental soft-tissue excess were observed, but they improved to different extent as time went by. CONCLUSIONS: Our treatment protocol for macrogenia is of great use to make the surgeries to be precisely and safely done with satisfactory results.

Application of computer techniques in repair of oblique facial clefts with outer-table calvarial bone grafts.

OBJECTIVE: This study focused on the application of computer-aided and rapid prototyping techniques in the repair of oblique facial clefts with outer-table calvarial bone. METHODS: Five patients with oblique facial clefts underwent repair with outer-table calvarial bone. A mirror technique and rapid prototyping techniques were applied to design and prefabricate the individualized template for the preoperative repair of orbital inferior wall and maxillary anterior wall defects. Using computer software, the ideal region from which to take outer-table calvarial bone was located according to the size and surface curvature of the individualized template. During the operation, outer-table calvarial bone was fixed according to the shape of the individualized template, and bone onlay grafting was carried out after appropriate trimming. Surgical accuracy was evaluated by comparing the preoperative and postoperative 3-dimensional reconstructed images. RESULTS: With computer-aided and rapid prototyping techniques, all 5 patients had an ideal clinical outcome with few complications. The 3-dimensional preoperative design images and postoperative images fit well. Six-month to 8-year postoperative follow-up demonstrated that 4 patients had good aesthetic facial appearances and 1 had developed recurrence of lower eyelid shortage. CONCLUSIONS: Computer-aided and rapid prototyping techniques can offer surgeons the ability to accurately design individualized templates for craniofacial deformity and perform a simulated operation for greatly improved surgical accuracy. These techniques are useful treatment modalities in the surgical management of oblique facial clefts.

Hyaluronic acid-based hydrogels: As an exosome delivery system in bone regeneration.

Exosomes are extracellular vesicles (EVs) containing various ingredients such as DNA, RNA, lipids and proteins, which play a significant role in intercellular communication. Numerous studies have demonstrated the important role of exosomes in bone regeneration through promoting the expression of osteogenic-related genes and proteins in mesenchymal stem cells. However, the low targeting ability and short circulating half-life of exosomes limited their clinical application. In order to solve those problems, different delivery systems and biological scaffolds have been developed. Hydrogel is a kind of absorbable biological scaffold composed of three-dimensional hydrophilic polymers. It not only has excellent biocompatibility and superior mechanical strength but can also provide a suitable nutrient environment for the growth of the endogenous cells. Thus, the combination between exosomes and hydrogels can improve the stability and maintain the biological activity of exosomes while achieving the sustained release of exosomes in the bone defect sites. As an important component of the extracellular matrix (ECM), hyaluronic acid (HA) plays a critical role in various physiological and pathological processes such as cell differentiation, proliferation, migration, inflammation, angiogenesis, tissue regeneration, wound healing and cancer. In recent years, hyaluronic acid-based hydrogels have been used as an exosome delivery system for bone regeneration and have displayed positive effects. This review mainly summarized the potential mechanism of HA and exosomes in promoting bone regeneration and the application prospects and challenges of hyaluronic acid-based hydrogels as exosome delivery devices in bone regeneration.

Pyroptosis-related lncRNA prognostic signatures for cutaneous melanoma and tumor microenvironment status.

Aims: To explore whether the expression of pyroptosis-related lncRNAs makes a difference in the prognosis and antitumor immunity of cutaneous melanoma (CM) patients. Methods: A series of analyses were conducted to establish a prognostic risk model and validate its accuracy. Immune-related analyses were performed to further assess the associations among immune status, tumor microenvironment and the prognostic risk model. Results: Eight pyroptosis-related lncRNAs relevant to prognosis were ascertained and applied to establish the prognostic risk model. The low-risk group had a higher overall survival rate. Conclusion: The established prognostic risk model presents better prediction ability for the prognosis of CM patients and provides new possible therapeutic targets for CM.

Clinical outcome of cranioplasty with high-density porous polyethylene.

BACKGROUND: High-density porous polyethylene (Medpor) has long been used in cranioplasty and is still one of the best materials for calvarial reconstruction. Calvarial defects can be effectively reconstructed with fewer complications by using Medpor. This article reports our study on the use of Medpor in reconstructing calvarial defects. METHODS: Twenty-three patients who underwent cranioplasty from 1999 to 2011 were included in this study. In all patients, Medpor was used for calvarial defect reconstruction, and all were followed up for at least 6 months. RESULTS: Most patients were satisfied with the reconstructive outcome. Only 1 patient had an infection and 1 had transient extradural seroma. All complications occurred within 2 years, and no new complications were found during the long-term follow-up. CONCLUSIONS: Using Medpor in cranioplasty is an effective method for reconstructing calvarial defects.

Porous polyethylene combined with split calvarial bone graft to cover complex calvarial defect.

BACKGROUND: Various kinds of grafts, such as autogenous bone grafts and alloplastic materials, can be used for the reconstruction of calvarial defects. The selection of the optimum material for the repair of cranial defects is the greatest problem in the reconstruction of calvarial defects. For some complex calvarial defects, simple use of autogenous bone grafts or alloplastic materials makes functional and cosmetic reconstruction difficult to achieve. Therefore, the current study uses a new method to repair complex calvarial defects. METHODS: Eight patients with complex calvarial defects underwent cranioplasty with porous polyethylene combined with split calvarial bone graft. Follow-up visits were conducted for 6 to 72 months to monitor the patients. RESULTS: Significant improvements in the contour of the skulls as well as in the aesthetic appearance of all the patients were observed. Moreover, no serious complications, such as infections, exposure, removal of the implants, and contour or implant abnormalities, were observed. Three cases displayed a transient extradural seroma collection, which was resolved through drainage and compression bandaging. CONCLUSIONS: The results of this pilot study indicate that the combined use of porous polyethylene and split calvarial bone graft may be useful for cranial reconstruction in patients with complex cranial defects.

Congenital skull defect and neurofibroma: without scalp and other abnormalities.

Congenital skull defect is a rare malformation that is usually associated with congenital anomalies of the scalp and comparable lesions in the brain, spinal cord, limbs, and skeletal muscle. Most previously reported cases have described skull defects with aplasia cutis congenita and other congenital abnormalities. Very few patients with skull defects present with an intact scalp or neurofibroma. The authors report an adult patient with a rare congenital skull defect and local neurofibroma.

HLA-DRB1: A new potential prognostic factor and therapeutic target of cutaneous melanoma and an indicator of tumor microenvironment remodeling.

Cutaneous melanoma (CM) is the most common skin cancer and one of the most aggressive cancers and its incidence has risen dramatically over the past few decades. The tumor microenvironment (TME) plays a crucial role in the occurrence and development of cutaneous melanoma. Nevertheless, the dynamics modulation of the immune and stromal components in the TME is not fully understood. In this study, 471 CM samples were obtained from TCGA database, and the ratio of tumor-infiltrating immune cells (TICs) in the TME were estimated using the ESTIMATE algorithms and CIBERSORT computational method. The differently expressed genes (DEGs) were applied to GO and KEGG function enrichment analysis, establishment of protein-protein interaction (PPI) network and univariate Cox regression analysis. Subsequently, we identified a predictive factor: HLA-DRB1 (major histocompatibility complex, class II, DR beta 1) by the intersection analysis of the hub genes of PPI network and the genes associated with the prognosis of the CM patients obtained by univariate Cox regression analysis. Correlation analysis and survival analysis showed that the expression level of HLA-DRB1 was negatively correlated with the Stage of the patients while positively correlated with the survival, prognosis and TME of melanoma. The GEPIA web server and the representative immunohistochemical images of HLA-DRB1 in the normal skin tissue and melanoma tissue from the Human Protein Atlas (HPA) database were applied to validate the expression level of HLA-DRB1. CIBERSORT analysis for the ratio of TICs indicated that 9 types of TICs were positively correlated with the expression level of HLA-DRB1 and only 4 types of TICs were negatively correlated with the expression level of HLA-DRB1. These results suggested that the expression level of HLA-DRB1 may be related to the immune activity of the TME and may affect the prognosis of CM patients by changing the status of the TME.

Antioxidant biocompatible composite collagen dressing for diabetic wound healing in rat model.

Associated with persistent oxidative stress, altered inflammatory responses, poor angiogenesis and epithelization, wound healing in diabetic patients is impaired. N-acetylcysteine (NAC) is reported to resist excess reactive oxygen species (ROS) production, prompt angiogenesis and maturation of the epidermis. Studies have revealed that graphene oxide (GO) can regulate cellular behavior and form cross-links with naturally biodegradable polymers such as collagen (COL) to construct composite scaffolds. Here, we reported a COL-based implantable scaffold containing a mixture of GO capable of the sustained delivery of NAC to evaluate the wound healing in diabetic rats. The morphological, physical characteristics, biocompatibility and NAC release profile of the GO-COL-NAC (GCN) scaffold were evaluated in vitro. Wound healing studies were performed on a 20 mm dorsal full-skin defect of streptozotocin (STZ)-induced diabetic rats. The injured skin tissue was removed at the 18th day post-surgery for histological analysis and determination of glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) activity. In diabetic rats, we confirmed that the GCN scaffold presented a beneficial effect in enhancing the wound healing process. Additionally, due to the sustained release of NAC, the scaffold may potentially induce the antioxidant defense system, upregulating the expression levels of the antioxidant enzymes in the wound tissue. The findings revealed that the antioxidant biocompatible composite collagen dressing could not only deliver NAC in situ for ROS inhibition but also promote the wound healing process. This scaffold with valuable therapy potential might enrich the approaches for surgeon in diabetic wound treatment in the future.

Delayed two steps PRP injection strategy for the improvement of fat graft survival with superior angiogenesis.

Platelet-rich plasma (PRP) has been widely used to improve the fat retention rate in autologous fat transplantation since it possesses a good angiogenesis capability in vivo. However, due to the short half-life of growth factors released from PRP and its uneven distribution in injected fat tissue, the strategy of PRP in fat transplantation needs further improvement. Since the capillaries started to grow into fat grafts in 1 week and vascular growth peaks in the second week after transplantation, we hypothesized that delayed two-steps PRP injection into the interior of grafts, accompanied with the extent of neovascularization might theoretically promote microvessel growth inside transplanted adipose tissue. 24 nude mice were divided into three groups: Blank group (0.35 mL fat mixed with 0.15 mL saline, N = 8), Single step group (0.35 mL fat mixed with 0.15 mLPRP, N = 8), and Two steps group (0.35 mL fat (day 0) + 0.075 mL PRP (day 7) + 0.075 mL PRP (day 14), N = 8). At 6 and 14 weeks post-transplantation, grafts were dissected, weighted, and assessed for histology, angiogenesis, fat regeneration and inflammation level. The weight and volume of the fat samples revealed no statistical difference among the three groups at 6 weeks after fat transplantation. The weight and volume of the Two steps group fat samples showed significantly higher compared to that in Blank and Single step groups at 14 weeks after fat transplantation (weight: 137.25 ± 5.60 mg versus 87.5 ± 3.90 mg,106.75 ± 2.94 mg, respectively; volume: 0.13 ± 0.01 mL versus 0.08 ± 0.01 mL, 0.09 ± 0.01 mL, respectively). Histological assessments indicated that delayed two-steps PRP injection strategy helps to improve adipose tissue content and reduce the composition of fibrous connective tissue at 14 weeks after fat transplantation. At 6 weeks and 14 weeks after transplantation, CD31 immunofluorescence indicated that delayed two-steps PRP injection strategy helps to improve angiogenesis and significantly higher compared to that in Blank and Single step groups (6 weeks: 28.75 ± 4.54 versus 10.50 ± 2.06, 21.75 ± 1.85; 14 weeks: 21.75 ± 2.86 versus 9.87 ± 2.08, 11.75 ± 1.47, respectively). Preadipocyte count indicated delayed two-steps PRP injection strategy might promote fat regeneration and significantly higher compared to that in Blank and Single step groups at 14 weeks (129.75 ± 6.57 versus 13.50 ± 3.50, 17.12 ± 6.23, respectively). In this study, we demonstrated that the novel delayed two-steps PRP injection strategy remarkably enhanced the long-term fat retention rate and improved the neovascularization extent in the interior of the fat graft. Platelet-rich plasma, Delayed two-steps injection, Angiogenesis, Fat transplantation.