Graft Retention Rate Research Articles

Retention Rate of Free Pericardial Fat Grafts after Bronchial Stump Coverage.

The postoperative course of the graft tissue after bronchial stump coverage remains unclear. We retrospectively analyzed 44 patients who underwent anatomical lung resection followed by bronchial stump coverage using free pericardial fat grafts. All patients underwent minimally invasive video-assisted thoracoscopic surgery. Computed tomography scans showed a graft retention rate of 100% on 60 days after surgery, 61% on 180 days, and plateauing at around 20% after 1 year. Free pericardial fat grafts, harvested minimally invasively, demonstrated a promising retention rate after surgery, making them a suitable option for patients with a high risk of bronchopleural fistula.

Tracking Fat Grafts by Magnetic Resonance Imaging: A Comparative Study of Adolescent and Adult Patients with Stable Localized Scleroderma.

The optimal timing of reconstruction for patients with facial localized scleroderma is uncertain. The purpose of this study was to compare the outcomes of autologous fat transplantation in adolescent and adult patients with stable localized scleroderma. Adolescent (age 10-19 years) and adult (age >19 years) patients with no previous surgery were enrolled (n = 10, each group). Preoperative magnetic resonance imaging (MRI), blood tests and dermatological assessments were used for disease activity assessment. All patients underwent autologous fat transplantation for anatomic facial fat restoration with preoperative MRI planning. Preoperative, immediate and one-year postoperative 3D Dixon MRI scans with image registration and fusion techniques were used for fat graft tracking. Patient satisfaction was assessed with a 5-point Likert scale. There was no significant difference in sex, body mass index, disease severity, or volume of injected fat between the two groups (p > 0.05), except for age (p < 0.05). The one-year postoperative fat graft retention rate was not significantly different, with 36.6 ± 2.4% (ranging from 25.3 to 49.3%) in the adolescent group and 32.9 ± 1.7% (ranging from 27.3 to 40.1%) in the adult group (p > 0.05). Surgical outcomes were favorable in all patients, with satisfaction scores of 3.8 ± 0.2 points in the adolescent group and 3.6 ± 0.2 points in the adult group (p > 0.05). In stable localized scleroderma, the initial autologous fat transplantation was equally effective for facial contour deformity improvement, with no significant difference in fat graft retention or satisfaction.

Breast fat grafting and cancer: a systematic review of the science behind enhancements and concerns.

Autologous fat transfer (AFT) is gaining popularity in breast surgery, offering a natural-looking and minimally invasive approach for augmentation, reconstruction, and contouring. However, concerns about its impact on breast cancer necessitate an understanding of the interplay between transplanted adipose-derived stem cells (ADSCs) and the breast tissue microenvironment. Renowned for regeneration, ADSCs raise questions about their role in cancer promotion. This systematic review delves into the complex relationship between AFT and breast cancer, exploring how ADSCs may influence development, growth, and metastasis. A systematic search of electronic databases, including PubMed, Embase, and BVS was conducted to identify relevant studies. The search strategy employed a combination of keywords, including "breast augmentation", "fat grafting", "breast enhancement", "mammoplasty", "cancer", "neoplasm" and related terms. Two reviewers independently screened titles and abstracts. Full-text articles were then retrieved for further evaluation based on their potential contribution to the review objectives. Two hundred and forty records were identified. Among these, 104 duplicates were removed, resulting in 136 reports available for title and abstract screening. Subsequently, 54 papers were deemed potentially eligible for inclusion, and all reports were retrieved. In vitro studies reveal ADSCs dual role in breast cancer, influencing proliferation, migration, and drug resistance through complex signaling pathways. Animal studies highlight distinct ADSC subpopulations impacting tumor growth via direct interactions and extracellular vesicle cargo. In vivo, ADSC-enriched fat grafting is generally safe, showing no increased cancer recurrence risk compared to other methods. Notably, cases of invasive breast carcinoma warrant special attention. ADSC-enriched fat grafts exhibit potential benefits in graft retention and survival rates. Despite promising evidence, further studies are needed to comprehensively understand the intricate relationship between ADSCs and breast cancer for optimized clinical applications and potential therapeutic innovations.

Autologous Fat Grafting as a Stand-Alone Procedure for Post-Mastectomy Breast Reconstruction and the Potential for Improvement using Adipose-Derived Stem Cells

Autologous fat grafting is an appealing method for breast reconstruction following mastectomy for breast cancer. Surgeons often perform this technique to optimize the aesthetic results of the more popular implant-based or autologous breast reconstruction by correcting residual defects and contour lines. Autologous fat grafting is less invasive, less costly, and easier than the reconstructive procedures mentioned. These advantages pose the possibility of using this method as a stand-alone procedure for post-mastectomy breast reconstruction. However, the literature is inconsistent when describing harvesting and processing methods and reporting patient outcomes. Graft retention rates are also variable. The use of adipose-derived stem cells can address the issue of unpredictable graft retention due to their angiogenic and adipogenic action. The novelty of using stem cells with autologous fat grafting also raises concerns, especially regarding its oncologic safety. This review aims to present a critical perspective of the literature on autologous fat grafting as a stand-alone procedure for post-mastectomy breast reconstruction and highlight areas for further research that can improve its outcome. Moreover, it discusses the potential use of adipose-derived stem cells in conjunction with autologous fat grafting to improve graft retention and the considerations surrounding the safety of this procedure.

Physical Expansion Preconditioning Promotes Host-Derived Adipocyte Dedifferentiation and Migration into Fat Grafts in a Murine Model.

The unstable recipient conditions after fat grafting remain an obstacle for tissue volumization. The interaction between fat grafts and recipient sites is not fully understood. The authors hypothesize that recipient-derived adipocytes undergo dedifferentiation and migrate into fat grafts in tissue regeneration. To observe the participation from recipient fat pad, the authors established a recipient adipocyte-tracing model where 0.2 mL of inguinal fat from 10 8-week-old C57BL/6 mice was grafted to 10 tamoxifen-treated AdipoqCre;mT/mG mice. Next, to evaluate the impact of physical force on recipient fat and fat graft, a murine internal expansion model was established by implanting a 1-mL internal expander on the inguinal fat pad of the lineage tracing mice that received fat graft from C57BL/6 mice. Transplanted adipose tissue was collected and analyzed by immunostaining of green fluorescent protein (GFP), tdTomato, perilipin, and CD31. In the observing model, immunostaining revealed that both GFP+ and tdTomato + cells from the recipient fat pad presented in fat grafts. Among the GFP + cells, most of them were perilipin + adipocytes and other perilipin - cells co-expressed octamer-binding transcription factor 4, indicating dedifferentiated adipocytes. In the internal expansion model, internal expansion increased GFP + cells in fat graft. Both octamer-binding transcription factor 4-positive/GFP + (0.23 ± 0.01 versus 0.12 ± 0.04) and perilipin + /GFP + (0.17 ± 0.02 versus 0.06 ± 0.01) cells were increased in the expanded group, compared with control. Host-derived adipocytes participate in fat graft regeneration through migration and dedifferentiation, which could be enhanced by internal expansion to increase fat graft retention rate. Further study using a larger animal model is needed, because this is a murine study. Surgeons are encouraged to use physical expansion preconditioning of the recipient site. Subsequent and multiple fat grafting into the fat layer is encouraged to obtain satisfactory soft-tissue volumization.

Adipose derived stem cell extracellular vesicles modulate primary human macrophages to an anti‐inflammatory phenotype in vitro

AbstractEVs released by adipose derived stem cells (ADSCs) have shown promise as a therapeutic for tissue repair because of their purported immune‐regulatory properties. Extracellular vesicles (EVs) from ADSCs could be beneficial in improving graft retention rates for autologous fat grafting (AFG) post‐mastectomy as, currently, grafted tissue rates are variable. Enriching grafted tissue with ADSC‐EVs may improve retention rates by modulating macrophages resident within both the breast and lipoaspirate. We aimed to identify key macrophage phenotypes that are modulated by ADSC‐EVs in vitro. ADSCs were isolated from lipoaspirates of women undergoing AFG and characterised by flow cytometry and differentiation potential. ADSC‐EVs were isolated from culture media and characterised by tuneable resistive pulse sensing, transmission electron microscopy and Western blot. Primary monocyte‐derived macrophages were polarized to an M1‐like (GM‐CSF, IFNγ), M2‐like phenotype (M‐CSF, IL‐4) or maintained (M0‐like; M‐CSF) and ADSC‐EVs were co‐cultured with macrophages for 48 h. Flow cytometry and high‐dimensional analysis clustered macrophages post co‐culture. A manual gating strategy was generated to recapitulate these clusters and was applied to a repeat experimental run. Both runs were analysed to examine the prevalence of each cluster, representing a unique macrophage phenotype, with and without ADSC‐EVs. Following the addition of ADSC‐EVs, M0‐like macrophages demonstrated a reciprocal shift of cell distribution from a cluster with a ‘high inflammatory profile’ (CD36+++CD206+++CD86+++; 16.5 ± 7.0%; p &lt; 0.0001) to a cluster with a ‘lower inflammatory profile’ (CD36+CD206+CD86+; 35 ± 21.5%; p &lt; 0.05). M1‐like macrophages shifted from a cluster with a ‘high inflammatory profile’ (CD206++CD11b++CD36++CD163++; 26.1 ± 9.4%; p = 0.0024) to a ‘lower inflammatory profile’ (CD206+CD11b+CD36+CD163+; 72.8 ± 8.7%; p = 0.0007). There was no shift in M2‐like clusters following ADSC‐EV treatment. ADSC‐EVs are complex regulators of macrophage phenotype that can shift macrophages away from a heightened pro‐inflammatory state.

Fat graft survival requires metabolic reprogramming toward the glycolytic pathway

Fat grafts are widely used as natural fillers in reconstructive and cosmetic surgery. However, the mechanisms underlying fat graft survival are poorly understood. Here, we performed an unbiased transcriptomic analysis in a mouse fat graft model to determine the molecular mechanism underlying free fat graft survival. We conducted RNA-sequencing (RNA-seq) analysis in a mousefree subcutaneous fat graft model on days 3 and 7 following grafting (n = 5). High-throughput sequencing was performed on paired-end reads using NovaSeq6000. The calculated transcripts per million (TPM) values were processed for principal component analysis (PCA), unsupervised hierarchically clustered heatmap generation, and gene set enrichment analysis. PCA and heatmap data revealed global differences in the transcriptomes of the fat graft model and the non-grafted control. The top meaningful upregulated gene sets in the fat graft model were related to the epithelial-mesenchymal transition, hypoxia on day 3, and angiogenesis on day 7. Mechanistically, the glycolytic pathway was upregulated in the fat graft model at days 3 (FDR q = 0.012) and 7 (FDR q = 0.084). In subsequent experiments, pharmacological inhibition of the glycolytic pathway in mouse fat grafts with 2-deoxy-D-glucose (2-DG) significantly suppressed fat graft retention rates, both grossly and microscopically (n = 5). Free adipose tissue grafts undergo metabolic reprogramming toward the glycolytic pathway. Future studies should examine whether targeting this pathway can enhance the graft survival rate.

Volumetric assessment of fat graft retention over implant by MRI

**Background**: Autologous fat grafting (AFG) is an increasingly popular adjunct to post-mastectomy breast reconstruction as it can produce a natural cosmetic outcome and alleviate undesirable radiotherapy-associated consequences, with low surgical risk. However, graft retention rates are variable and unpredictable. In order to improve and understand what influences graft retention rates, accurate and consistent methods for the measurement of graft retention must be developed.**Methods**: Twenty patients who were undergoing AFG following a previous mastectomy were prospectively enrolled. Of these, six women suitable for immediate breast reconstruction (IBR) with implant underwent MRI pre- and three months post-AFG. **Results**: All patients had a net gain in volume at three months post-procedure with a mean of 123.6 ± 56.07cm^3^; however, the percentage retention ranged from 30.0 to 104.7 per cent. **Conclusions**: This study has demonstrated the feasibility of measuring AFG retention over implant using MRI, as well as confirming variable tissue retention rates. This is an important step forward for studies on improving overall graft survival.

Effects of Melatonin on Fat Graft Retention Through Browning of Adipose Tissue and Alternative Macrophage Polarization.

Melatonin is a widely used drug that can affect adipocyte inflammation, resulting in adipose tissue browning. Inducing the browning of white fat and changing the inflammatory microenvironment of early transplanted fat have positive effects on the retention rate of fat grafts. This study aimed to evaluate the effects of melatonin on fat graft retention, determine whether it is related to adipose tissue browning and the inflammatory microenvironment, and explore the underlying mechanisms. A C57BL/6 mice fat transplantation model was established. The mice were divided into a control group (ethanol), a high-dose group (40 mg/kg/day melatonin), a medium-dose group (20 mg/kg/day melatonin), and a low-dose group (10 mg/kg/day melatonin). They were also given oral gavage treatment for 2 weeks. The grafted fat was collected 2, 4, and 12 weeks after treatment. The medium-dose and high-dose melatonin groups had significantly higher fat graft retention rates than the control group at 12 weeks. The medium-dose melatonin group had smaller multilocular adipocytes, which enhanced the expression of uncoupling protein 1 and increased neovascularization in the grafted fat. The medium-dose group also had a higher distribution of M2 macrophages. These findings suggest that melatonin administration can improve the retention of fat grafts through polarization of macrophages toward the anti-inflammatory type and induction of adipose tissue browning. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 .

Condensing of Low-Density Fat by Mechanical Process Improves Fat Retention and Reduces Oil Cyst Formation in Breast Reconstruction.

Although autologous fat grafting is a useful adjunct for breast reconstruction, its indications remain limited as large-volume fat grafting results in high absorption and complication rates. Low-density fat includes small numbers of viable cells and considerable oil, resulting in nodules and oil cysts. This study evaluated the volumization effect and complications with combined fat grafting of condense low-density fat and high-density fat. This retrospective, single-center study included 25 patients who underwent combined grafting of condensed low-density fat and high-density fat (CLDF + HDF) and 20 patients who underwent conventional Coleman fat grafting for breast reconstruction from December 2017 to January 2022. Retention rates and complications were evaluated by magnetic resonance imaging and ultrasound rates. Patient satisfaction was evaluated using a typical Likert scale. Photographs were taken and imageological examinations were performed before and after treatment. Graft retention rate was higher in patients who underwent CLDF + HDF than Coleman fat grafting for breast reconstruction (38.40 ± 4.41% vs. 31.43 ± 5.43%, p <0.05). One patient in the CLDF + HDF grafting group, compared with twelve in the Coleman fat grafting group, developed oil cysts exceeding 1 cm. Patient satisfaction rate was higher in the CLDF + HDF grafting group. Mechanical processes can concentrate the cellular content of LDF and remove oil, condensing LDF to the level of HDF. Combined grafting of CLDF optimized by mechanical processing and HDF is effective for breast reconstruction, with a higher retention rate and a lower incidence of complications than conventional Coleman fat grafting. 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 .

A Preliminary Exploratory Study of Autologous Fat Transplantation in Breast Augmentation With Different Fat Transplantation Planes.

BackgroundAutologous fat transfer is common in breast augmentationor reconstruction. However, AFG recipient site in the breast for fat grafting has not been carefully investigated.MethodsForty female patients requiring breast augmentation with fat grafting were randomly assigned into two groups. The retromammary group received 2/3 fat into the retromammary space and the other 1/3 into the subcutaneous and retropectoral planes. The retropectoral group received 2/3 fat into the retropectoral plane and the other 1/3 into the subcutaneous and retromammary planes. The fat grafting result at 6 months was assessed by 3D laser surface scanning and then ultrasound. Any complications were recorded during follow-up. Samples from a patient who underwent fat grafting for 6 months was obtained and histological examination was conducted.ResultsNo significant difference in the retention rate after 6 months was observed between the two groups (retromammary group: 35.9% ± 6.6; retropectoral group: 39.3% ± 5.1, p = 0.1076). The retromammary grouphad a higher incidence of oil cyst formation than the retropectoral group. Histological examination showed that there were more oil cysts and mac2 positive macrophage infiltration in the fat cells in retromammary group, while retropectoral group had more small-size adipocytes.ConclusionAlthough fat grafting into the retropectoral plane did not provide a superior fat graft retention rate, it did lower the incidence of complications. The retropectoral space show great potential to become a favorable recipient site.

Alternatively activated macrophages at the recipient site improve fat graft retention by promoting angiogenesis and adipogenesis.

The inflammatory response mediated by macrophages plays a role in tissue repair. Macrophages preferentially infiltrate the donor site and subsequently, infiltrate the recipient site after fat grafting. This study aimed to trace host‐derived macrophages and to evaluate the effects of macrophage infiltration at the recipient site during the early stage on long‐term fat graft retention. In our novel mouse model, all mice underwent simulated liposuction and were divided into 2 groups. The fat procurement plus grafting (Pro‐Grafting) group was engrafted with prepared fat (0.3 ml). The pro‐Grafting+M2 group was engrafted with prepared fat (0.3 ml) mixed with 1.0 × 106 GFP+M0 macrophages, and then, 2 ng IL‐4 was injected into the grafts on Day 3. In addition, 1.0 × 106 GFP+M0 macrophages were injected into the tail vein for tracing in the Pro‐Grafting group. As a result, GFP+macrophages first infiltrated the donor site and subsequently infiltrated the recipient site in the Pro‐Grafting group. The long‐term retention rate was higher in the Pro‐Grafting+M2 group (52% ± 6.5%) than in the Pro‐Grafting group (40% ± 3.5%). CD34+ and CD31+ areas were observed earlier, and expression of the adipogenic proteins PPAR‐γ, C/EBP and AP2 was higher in the Pro‐Grafting+M2 group than in the Pro‐Grafting group. The host macrophages preferentially infiltrate the donor site, and then, infiltrate the recipient site after fat grafting. At the early stage, an increase in macrophages at the recipient site may promote vascularization and regeneration, and thereby improve the fat graft retention rate.

Bone marrow mesenchymal stem cells enhance angiogenesis and promote fat retention in fat grafting via polarized macrophages

BackgroundFat grafting is one of the most common soft tissue filling methods in plastic surgery. Bone marrow mesenchymal stem cell (BM-MSC) transplantation is an effective method for improving graft retention. However, the role of BM-MSCs in fat transplantation is not completely clear.MethodsHuman fat particles, together with BM-MSCs or PBS as a control, were subcutaneously transplanted into the backs of nude mice. Samples were taken on days 14, 30 and 90 post-grafting to calculate the fat graft retention rate, and tissue staining was evaluated. Furthermore, macrophages were treated with BM-MSC conditioned medium (BM-MSC-CM) to identify the beneficial component secreted by these stem cells.ResultsIn this study, we found that BM-MSCs improved retention by enhancing angiogenesis in fat grafting. Further analysis revealed that BM-MSCs could significantly inhibit the expression of the proinflammatory M1 macrophage markers interleukin (IL)-1β, tumor necrosis factor-α (TNF-α) and IL-6 in the early stages of fat grafting and promote the expression of the anti-inflammatory M2 macrophage markers Arg1, IL-10 and VEGF. Furthermore, our results showed that IL-10 secreted by BM-MSCs induced M2 macrophage polarization in vitro.ConclusionsBM-MSC transplantation can improve the fat retention rate and promote angiogenesis, which may be related to M2 macrophages. These results help elucidate the role of BM-MSCs in fat grafting.

Induced Beige Adipocytes Improved Fat Graft Retention by Promoting Adipogenesis and Angiogenesis.

Fat grafting is commonly used in treating soft-tissue defects. However, the basic biology behind fat grafting is still not fully understood. Evidence of adipose browning into beige adipose tissue after fat grafting was revealed, but its role in fat grafting remains unclear. Induced beige adipocytes and adipose-derived stem cells were obtained from human lipoaspirates and labeled with green fluorescent protein. Nude mice were each injected with 300 mg of human lipoaspirate containing green fluorescent protein-labeled adipose-derived stem cells, green fluorescent protein-labeled induced beige adipocytes, or phosphate-buffered saline. Grafted fat was harvested after 1, 4, 8, and 12 weeks for immunohistochemistry and histologic examination. Graft retention, vascularization, and adipogenic gene expression were compared. After 7 days' induction, adipocytes achieved browning with multilocular lipid droplets, increased mitochondria, and up-regulated browning gene expression. Fat graft retention rates at week 12 were significantly higher after injection of induced beige adipocytes than after injection of phosphate-buffered saline (46.0 ± 4.9 percent versus 31.0 ± 3.6 percent; p = 0.01), but were similar after injection of induced beige adipocytes and adipose-derived stem cells (p > 0.05). Induced beige adipocytes underwent rewhitening into white adipocytes and showed up-regulation of peroxisome proliferator-activated receptor-γ expression. Induced beige adipocytes enhanced angiogenesis, but were not active in forming vessel structures. Induced beige adipocytes and adipose-derived stem cells were comparable in improving fat graft retention rates. Induced beige adipocytes promote angiogenesis in a paracrine manner and are prone to rewhitening after fat grafting.

A Systematic Review on Extracellular Vesicles-Enriched Fat Grafting: A Shifting Paradigm.

Recent evidence confirms that mesenchymal stem cells (MSCs) facilitate angiogenesis mainly through paracrine function. Extracellular vesicles (EVs) are regarded as key components of the cell secretome, possessing functional properties of their source cells. Subsequently, MSC-EVs have emerged as a novel cell-free approach to improve fat graft retention rate. The authors sought to provide a systematic review of all studies reporting the utilization of MSC-EVs to improve graft retention rate. A systematic search was undertaken employing the Embase, PubMed, and Cochrane Central Register of Controlled Trials databases. Outcome measures included donor/receptor organism of the fat graft, study model, intervention groups, evaluation intervals, EV research data, and in vitro and in vivo results. Of the total 1717 articles, 62 full texts were screened. Seven studies reporting on 294 mice were included. Overall, EV-treated groups showed higher graft retention rates compared with untreated groups. Notably, retention rate was similar following EV and MSC treatment. In addition to reduced inflammation, graft enrichment with EVs resulted in early revascularization and better graft integrity. Interestingly, hypoxic preconditioning of MSCs improved their beneficial paracrine effects and led to a more proangiogenic EV population, as observed by both in vitro and in vivo results. MSC-EVs appear to offer an interesting cell-free alternative to improve fat graft survival. Although their clinical relevance remains to be determined, it is clear that not the cells but rather their secretome is essential for graft survival. Thus, a paradigm shift from cell-assisted lipotransfer towards "secretome-assisted lipotransfer" is well on its way.

A Prospective Study of the Efficacy of Cell-Assisted Lipotransfer with Stromal Vascular Fraction to Correct Contour Deformities of the Autologous Reconstructed Breast.

Autologous lipotransfer has increasingly become popular for breast reconstruction. Moreover, owing to the emergence of information regarding the efficacy of stromal vascular fraction (SVF) in terms of oncological safety and survival rate, procedures based on cell-assisted lipotransfer (CAL) have been widely employed recently. However, quantitative data of CAL with SVF are lacking. We evaluated the efficacy of CAL using SVF on survival rate in breast reconstruction. A 12-month prospective study was conducted for 20 patients (20 breasts) requiring breast asymmetry correction due to volume deficit following autologous breast reconstruction using a transverse rectus abdominis myocutaneous flap or latissimus dorsi flap after total mastectomy. After the patients were equally divided into two groups-fat graft with SVF (Group 1, n = 10) and without SVF (Group 2, n = 10)-, the variance of breast volume was measured using three-dimensional scanning to analyze fat graft retention rate. Moreover, patient satisfaction and complications were investigated. Fat graft retention rate was higher in Group 1 than in Group 2 at both postoperative 6months (73.8% vs. 62.2%; p = 0.03) and 12months (65.4% vs. 48.4%; p = 0.03). Group 1 showed higher patient satisfaction. Regarding complications, fat necrosis occurred in 1 patient each in both groups. However, locoregional recurrence was not observed in any patient during follow-up. CAL with SVF is effective in increasing survival rates of autologous fat grafts for correction of volume deficit after breast reconstruction. Moreover, it is associated with improved patient satisfaction in terms of the esthetic aspect. 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.

Botulinum Toxin A Improves Supramuscular Fat Graft Retention by Enhancing Angiogenesis and Adipogenesis.

Autologous fat grafting is commonly used for soft-tissue augmentation and reconstruction in plastic surgery. However, long-term graft retention rates are unpredictable, especially in muscle-related fat grafting. To determine whether botulinum neurotoxin type A (BoNTA) may improve supramuscular fat grafting retention by reducing muscle movement, thereby enhancing angiogenesis and adipogenesis. Pre-BTX+ nude mice were injected with BoNTA on the right quadriceps femoris and underwent supramuscular fat grafting 1 week later. BTX+ nude mice simultaneously underwent BoNTA injection and transplantation. Control nude mice underwent transplantation without BoNTA. Graft volumes were determined, and grafts underwent histological analyses and immunostaining. CatWalk XT gait analysis was conducted on BTX+ mice. Pre-BTX+ and BTX+ groups had significantly higher retention rates and exhibited better angiogenesis and adipocyte survival than the Control group. BoNTA injections improved the long-term retention of supramuscular fat grafts by reducing muscle movement, possibly by augmenting angiogenesis and adipogenesis.

Exosomes Are Comparable to Source Adipose Stem Cells in Fat Graft Retention with Up-Regulating Early Inflammation and Angiogenesis.

Exosomes derived from mesenchymal stem cells possess functional properties similar to those of their parent cells, suggesting that they could play a pivotal role in tissue repair and regeneration. Using lipotransfer as a surrogate, exosomes were isolated from mouse adipose-derived stem cell-conditioned medium and characterized. Minced fat tissue mixed with exosomes, source cells (cell-assisted lipotransfer), or saline was implanted subcutaneously in the lower back of C57/BL mice bilaterally (n = 16 each). Transferred fat tissues were harvested and analyzed at 3 and 10 weeks. At 3 and 10 weeks after the transfer, fat grafts in groups of exosomes and cell-assisted lipotransfer showed better fat integrity, fewer oil cysts, and reduced fibrosis. At week 10, graft retention rates in cell-assisted lipotransfer (50.9 ± 2.4 percent; p = 0.03) and exosome groups (56.4 ± 1.6 percent; p < 0.001) were significantly higher than in the saline group (40.7 ± 4.7 percent). Further investigations of macrophage infiltration, inflammatory factors, angiogenic factors, adipogenic factors, and extracellular matrix revealed that those exosomes promoted angiogenesis and up-regulated early inflammation, whereas during mid to late stages of fat grafting, they exerted a proadipogenic effect and also increased collagen synthesis level similarly to their source cells. The adipose-derived stem cell-derived exosomes demonstrated effects comparable to those of their source cells in achieving improved graft retention by up-regulating early inflammation and augmenting angiogenesis. These features may enable exosomes to be an attractive cell-free alternative in therapeutic regenerative medicine.

Adipogenesis for soft tissue reconstruction.

It has been increasingly common to use adipose tissue for regenerative and reconstructive purposes. Applications of autologous fat transfer and different stem cell therapies have significant limitations and adipose tissue engineering may have the potential to be an important strategy in the reconstruction of large tissue defects. A better understanding of adipogenesis will help to develop strategies to make adipose tissue more effective for repairing volumetric defects. We provide an overview of the current applications of adipose tissue transfer and cellular therapy methods for soft tissue reconstruction, cellular physiology, and factors influencing adipogenesis, and adipose tissue engineering. Furthermore, we discuss mechanical properties and vascularization strategies of engineered adipose tissue, and its potential applications in the clinical settings. Autologous fat tissue transfer is the standard of care technique for the majority of surgeons; however, high resorption rates, poor perfusion within a large volume fat graft and widely inconsistent graft survival are the main limitations. Adipose tissue engineering is a promising field to reach the first goal of producing adipose tissue which has more predictable survival and higher graft retention rates. Advancements of scaffold and vascularization strategies will contribute to metabolically and functionally more relevant adipose tissue engineering.

Endoscopic tympanoplasty with limited tympanomeatal flap elevation in pediatric cases: comparison of anatomic and audiological results of grafts.

The anatomical and functional success rates of tragal cartilage perichondrium and temporal muscle fascia, in pediatric patients who underwent endoscopic type 1 tympanoplasty with limited tympanomeatal flap elevation, were compared. In total, 35 pediatric patients (21 females, 14 males; mean age 11.0 ± 1.5years; range 8-14years) who underwent transcanal endoscopic type 1 tympanoplasty with limited elevation of the tympanomeatal flap were included in this study. Patients in group A received a tragal cartilage perichondrium graft and those in group B received a temporal muscle fascia graft. The groups were compared with respect to the pre- and postoperative air-bone gap (ABG) and tympanic membrane status. The mean preoperative and postoperative ABG were 27.0 ± 9.2 and 9.0 ± 8.5dB in group A, and 26.8 ± 8.8 and 11.6 ± 9.2dB in group B, respectively. The group differences in pre- and postoperative ABG values were not significant (p = 0.882 and p = 0.417, respectively). However, in both groups, the postoperative ABG was significantly lower than the preoperative ABG (both p = 0.0001). The graft retention rate was 100% in group A and 88.2% in group B; the difference was not statistically significant (p = 0.134). There was also no statistically significant difference between the pre- and postoperative bone conduction values of the patients at 0.5, 1, 2, 3 or 4kHz (all p > 0.05). Our study demonstrated that in pediatric patients undergoing endoscopic tympanoplasty, both the tragal cartilage perichondrium and the temporal muscle fascia can be used successfully and safely as grafts in endoscopic type 1 tympanoplasty performed by limited tympanomeatal flap elevation.