Volume Retention Rate Research Articles

The effect of exogenous mitochondria in enhancing the survival and volume retention of transplanted fat tissue in a nude mice model

BackgroundDespite the pivotal role of fat grafting in plastic, reconstructive, and aesthetic surgery, inconsistent survival rates of transplanted adipose tissue, primarily due to early ischemic and hypoxic insults, remain a significant challenge. The infusion of healthy mitochondria has emerged as a promising intervention to support tissue recovery from ischemic, hypoxic, and other types of damages across various organ systems.ObjectivesThis study aims to evaluate the impact of supplementing human adipose tissue grafts with healthy exogenous mitochondria on their volume and mass retention rates when transplanted into the subcutaneous layers of nude mice. This approach seeks to improve and optimize fat grafting techniques.MethodsHuman adipose tissues were preconditioned with exogenous mitochondria (10 µg/mL), a combination of exogenous mitochondria and the inhibitor Dyngo-4a, Dyngo-4a alone, or PBS, and then transplanted into the subcutaneous tissue of 24 nude mice. Samples were harvested at 1 and 3 months post-transplantation for analysis of mass and volume retention. The structural morphology and integrity of the adipose tissues were assessed using Hematoxylin and Eosin (H&E) staining.ResultsMitochondrial preconditioning significantly enhanced the retention of mass and volume in fat grafts, demonstrating superior structural morphology and integrity compared to the control group.ConclusionsThis study highlights the potential of exogenous mitochondrial augmentation in fat transplantation to significantly improve fat graft survival, thereby optimizing the success of fat grafting procedures.

What Patient-related Factors Most Strongly Influence Autologous Fat Grafting Volume Retention in Breast Augmentation?

Background: Regarding autologous fat grafting for breast augmentation, the factors influencing volume retention are unclear. Few studies have assessed which factors, particularly patient-related variables, could affect volume retention and to what extent, without performing multivariate analysis. In this study, we performed three-dimensional breast volume measurements before and after autologous fat grafting, calculated the volume and volume retention, and investigated factors that may affect volume retention. Methods: A total of 204 breasts that underwent autologous fat grafting by the same surgeon at our hospital between May 25 and December 25, 2021 were included. Volumetric measurements were taken preoperatively and at 1, 3, and 6 months postoperatively using a three-dimensional camera; volume retention was calculated. Linear mixed model analysis was performed to examine the effects of age, body mass index, number of total autologous fat grafting procedures, pregnancy and lactation history, smoking status, fat processing techniques (sedimentation versus centrifugation), preoperative volume, and weight change at the 3- and 6-month postoperative volume retention analyses. Results: Using multivariate analysis, the preoperative volume was found to be a significant factor at 3 and 6 months. The preoperative volume affected fat volume retention rate by 0.004 (P = 0.001) and 0.008 (P = 0.011) per 10 mL at 3 and 6 months, respectively. Conclusions: The preoperative volume likely affected fat volume retention. Specifically, a 100-mL increase in the preoperative breast volume might increase the volume retention by 4%–8%. Preoperative volume is an important confounding factor for future studies.

What Drives Deep Reader Engagement with Socially-Generated Content? The Critical Role of Dual-Layer Information

Social media platforms have rapidly gained popularity due to features such as personalized recommendations and real-time push notifications, attracting a large number of creators to produce content. However, with the explosive growth of content and information overload, readers’ expectations for content and interaction quality have increased, making it increasingly difficult to engage them deeply. This poses management challenges to the platform’s ecosystem, such as high visitor volume but low retention rates. This study, leveraging the latest GPT technology, provides a more scientific approach to content metrics and a detailed exploration of interaction categories to examine the impact of information, authors, and interactions on reader engagement behavior. It particularly considers the effects of internal and external layers of social-generated content and different levels of reader engagement. Combining real community data, it is found that the impact of content information is the most crucial, with this impact being distributed across content and interaction aspects. It is suggested that social media platforms should strive to balance vivacity and informativeness when producing content. Additionally, the role of content, authors, and interactions varies across different product categories, so differentiated strategies should be employed accordingly.

Survival Mechanisms and Retention Strategies in Large-Volume Fat Grafting: A Comprehensive Review and Future Perspectives.

Large-volume fat grafting is emerging as a promising technique in plastic and reconstructive surgery. However, the unpredictable graft volume retention rate remains a critical challenge. To address this issue, we need a profound understanding of the survival mechanisms following large-volume fat transplantation. This review summarizes known survival mechanisms and strategies to enhance graft retention. This review comprehensively examines the current literature on the survival mechanisms and retention strategies in large-volume fat grafting. A thorough literature search was conducted using PubMed, Medline and Google Scholar databases, focusing on studies published from 2009 to 2023. In the current research on fat survival mechanisms, few have focused on large-volume fat grafting. This review provides an overview of the survival mechanisms specific to large-volume fat grafting and identifies a survival pattern distinct from that of small-volume fat grafting. Additionally, we have summarized existing strategies to improve graft retention across five stages (harvesting, processing, enrichment, grafting and post-graft care), analyzed their advantages and disadvantages and identified some of the most promising strategies. 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.

Concentrated Deoiled Fat: A Novel Method of Fat Processing to Improve Fat Graft Survival-A Basic Research.

Oil compromises graft outcomes via inflammation, which accounts for the unpredictability of volume retention rates as low as 20%. Existing techniques for oil removal are relatively inefficient. In this study, a novel approach was taken to prepare concentrated deoiled fat (CDF) by utilizing flocculation and centrifugation to remove the oil. The hypothesis put forward in this study was that CDF would exhibit improved volume retention and quality by enhancing purification efficiency and reducing inflammation. This basic research involved both in vitro and in vivo experiments using samples obtained from women who underwent abdominal liposuction. The CDF was prepared by flocculation and centrifugation. In the vitro experiments, the microstructure of fat was assessed using Calcein acetoxymethyl ester (AM) staining for living cells and propidium iodide (PI) staining for dead nuclei in two groups: Coleman fat group and CDF group. Additionally, the glucose uptake capacity of these two groups was evaluated using the glucose transport test (GTT). In the vivo experiments, the study included three groups: two experimental groups (low-volume concentrated deoiled fat, LCDF; high-volume concentrated deoiled fat, HCDF) and one control group (Coleman fat), with 10 healthy female BALB/c nude mice in each group, 1ml of the graft was injected subcutaneously to each mouse. After 8weeks, the fat grafts were harvested and subjected to volume evaluation, HE staining and immunostaining for perilipin to assess graft outcomes. In the vitro experiments, the concentration rate of the CDF was found to be 79.6% that of Coleman fat, with 15.1% more oil separated. Cell viability, as assessed by AM/PI staining, did not show a significant difference between the two grafts, but the results of the GTT showed that the tissue viability of the CDF was higher than that of Coleman fat. In the vivo experiments, the CDF had higher volume retention than Coleman fat, as measured by water displacement. Histopathologic scoring indicated that HCDF group and LCDF group had a more intact fat structure with fewer vacuoles, inflammation, and fibrosis compared to Coleman fat. Additionally, the percentages of perilipin-positive area in the LCDF group and HCDF group were higher than in the Coleman group, indicating improved graft quality and outcome with the use of concentrated deoiled fat. "Concentrated deoiled fat" refers to an autologous fat graft from which oil has been removed by flocculation and centrifugation. This process increases volume retention and viable cells and decreases infiltrated inflammatory cells. 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 .

Enhancing Fat Graft Survival via Upregulating Autophagy of Adipocytes.

Autophagy is a cellular self-protection mechanism. The upregulation of adipose-derived stem cells' (ADSCs) autophagy can promote fat graft survival. However, the effect of interfering with adipocyte autophagy on graft survival is still unknown. In addition, autophagy is involved in adipocyte dedifferentiation. We investigated the effect of autophagy on adipocyte dedifferentiation and fat graft survival. The classic autophagy regulatory drugs rapamycin (100nM) and 3-methyladenine (3-MA; 10mM) were used to treat adipocytes, adipocyte dedifferentiation was observed, and their effects on ADSCs were detected. In our experiments, 100nM rapamycin, 10mM 3-MA and saline were mixed with human adipose tissue and transplanted into nude mice. At 2, 4, 8 and 12 weeks postoperatively, the grafts were harvested for histological and immunohistochemical analysis. Rapamycin and 3-MA can promote and inhibit adipocyte dedifferentiation by regulating autophagy. Both drugs can inhibit ADSC proliferation, and 10mM 3-MA can inhibit ADSC adipogenesis. At weeks 8 and 12, the volume retention rate of the rapamycin group (8 weeks, 64.77% ± 6.36%; 12 weeks, 56.13% ± 4.73%) was higher than the control group (8 weeks, 52.62% ± 4.04%; P < 0.05; 12 weeks, 43.17% ± 6.02%; P < 0.05) and the rapamycin group had more viable adipocytes and better vascularization. Compared with the control group, the volume retention rate, viable adipocytes and vascularization of the 3-MA group decreased. Rapamycin can promote adipocyte dedifferentiation by upregulating autophagy to promote fat graft survival. 3-MA can inhibit graft survival, but its mechanism includes the inhibition of adipocyte dedifferentiation and ADSC proliferation and adipogenesis. 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 .

Autologous fat grafting for cosmetic temporal augmentation: a systematic review.

Autologous fat grafting for temporal augmentation is increasingly popular in aesthetic surgery. However, its high absorption rate, unpredictable volume retention rate, and potential safety risks are significant drawbacks. Evaluation methods for the fat graft survival rate, especially volume retention in the temporal area, vary widely and tend to be more subjective than objective. Therefore, this systematic review aims to analyze the unpredictable volume retention rate, associated safety concerns, and the various assessment strategies following autologous fat grafting for cosmetic temporal augmentation. We conducted a systematic review of manuscripts listed in the MEDLINE/PubMed database on autologous fat grafting for cosmetic temporal augmentation. Articles had to be available in full text and written in English. Studies not presenting human data or not discussing cosmetic indications were excluded. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eight articles were included. The average fat volume injected into each temporal region was 10.69 ml (range 6-17.5) on the right and 10.64 ml (range 5.9-17.4) on the left side. All included articles utilized photographic documentation before and after treatment, along with various questionnaires and scales (37.5% Likert Scale, 12.5% Hollowness Severity Rating Scale, 12.5% Visual Analogue Scale, 12.5% Allergan Temple Hollowing Scale). For objective assessment, one article (12.5%) used computed tomography, and another (12.5%) employed a three-dimensional scanning system to objectively evaluate fat graft survival. Autologous fat grafting effectively addresses temporal hollowness, with high patient satisfaction and a favorable safety profile. However, the variability in fat retention rates highlights the need for more controlled studies to establish reliable, validated methods for evaluating fat graft survival in the temporal area, and to further assess the safety of this procedure.

Pyrroloquinoline Quinone (PQQ) Improves Long-term Survival of Fat Grafts by Alleviating Oxidative Stress and Promoting Angiogenesis During the Early Phase After Transplantation.

Reducing absorption after autologous fat grafting is a current challenge. Pyrroloquinoline quinone (PQQ) is the strongest known catalyst of redox reactions, which can scavenge reactive oxygen species (ROS) and alleviate oxidative stress. The aim of this study was to establish an in vivo model of PQQ-assisted lipotransfer and clarify the role of PQQ in reducing oxidative stress, alleviating apoptosis, and promoting angiogenesis during the acute hypoxic phase after grafting. In addition the study was performed to assess whether this intervention would have a positive effect on the improvement of long-term volume retention. Different concentrations of PQQ (low: 10 μM, medium: 100 μM, and high: 1000 μM) were mixed with human adipose tissue and transplanted subcutaneously into nude mice. Meanwhile, a control group of phosphate-buffered saline in an equal volume to PQQ was set up. On the third day after grafting, whole mount fluorescence staining was applied to detect ROS, mitochondrial membrane potential (MMP), apoptosis, adipocyte activity, and angiogenesis. Graft volume retention rate and electron microscopic morphology were evaluated at the third month. Immunohistochemistry and polymerase chain reaction (PCR) were further employed to elucidate the mechanism of action of PQQ. PQQ-assisted fat grafting improved the long-term volume retention, promoted the quality and viability of the adipose tissue, and reduced the level of fibrosis. The underlying mechanism of PQQ assisted in scavenging the accumulated ROS, restoring MMP, enhancing adipocyte viability, alleviating tissue apoptosis, and promoting timely angiogenesis during the hypoxia stress phase. The most effective concentration of PQQ was 100 μM. Immunohistochemistry and PCR experiments confirmed that PQQ reduced the expression of Bax and cytochrome c in the mitochondrial apoptotic pathway and increased the level of the antiapoptotic molecule Bcl-2. PQQ could improve the long-term survival of adipocytes by alleviating hypoxic stress and promoting timely angiogenesis in the early phase following lipotransfer.

Ferroptosis in Autologous Fat Transplantation: A New Hypothesis.

Autologous adipose tissue transplantation is widely used for cosmetic and reconstruction of various areas in the body, often to repair soft tissue volume loss or contoured deformation. However, the application of fat transplantation is limited by unstable and unpredictable volume retention rates. At present, promoting adipose tissue survival and inhibiting its death is the key to improve the effect of autologous fat transplantation. In this paper, we propose a hypothesis that ferroptosis exists in fat transplantation. The bases of this hypothesis include the following: (1) the association between ferroptosis and other programmed cell death; (2) the association between ferroptosis and ischemia-reperfusion injury; and (3) the use of ferroptosis inhibitors in the field of fat transplantation.

Stem Cell-Enriched Fat Grafts Versus Autologous Fat Grafts for Facial Reconstruction: A Systematic Review and Meta-analysis.

The aim of the study is to compare the outcomes of stem cell-enrichment fat grafting versus routine fat grafting for facial reconstruction purposes. A systematic review and meta-analysis were performed as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses Guidelines and a search of electronic information was conducted to identify all randomized controlled trials, case control studies, and cohort studies comparing the outcomes of stem cell enrichment fat grafting versus routine fat grafting for facial reconstruction purposes. Volume retention and infection rate were primary outcome measures. Secondary outcome measures included patient satisfaction postsurgery, redness and swelling, fat necrosis, cysts, as well as operation time. Fixed and random effects modeling was used for the analysis. Eight studies enrolling 275 subjects were selected. There was a significant difference between the stem cell enrichment fat grafting and routine grafting groups in terms of mean volume retention (standardized mean difference, 2.49; P < 0.00001). However, there was no significant difference between the 2 groups in the rate of infection (odds ratio, 0.36; P = 0.30). For all secondary outcomes, the intervention group had similar results compared with the control group except for the operation time, which was shorter in the latter. Stem cell-enriched fat grafting is a superior option when compared with the routine fat grafting for facial reconstruction surgery because it improves the mean volume retention and does not worsen patient satisfaction and surgical complications.

Three-Dimensional Volumetric Analysis of the Effect of Interval Time in Autologous Fat Graft Breast Augmentation.

Autologous adipose tissue has become increasingly popular in cosmetic and plastic reconstructive surgery, especially breast augmentation surgery. However, the volume retention rate after transplantation significantly varies and may be unsatisfactory. Many patients need two or more autologous fat graft breast augmentations to achieve the expected effect. There are currently no studies on optimal timing between fat injections. We identified target patients with secondary or multiple autologous fat transplantations by inclusion and exclusion criteria and used three-dimensional scanning technology to calculate the volume retention. Patients were divided into two groups according to the dates of the first and second operations (group A: interoperative time < 120 days, group B: interoperative time ≥ 120 days). We used SPSS 26 for statistical calculations. We included 161 patients in this retrospective study, with an average volume retention rate of 36.56% in group A (n = 85) and 27.45% in group B (n = 76). The independent sample t test showed that the volume retention rate in group A was higher than that in group B (P < 0.001). And the paired t test showed there is a significant improvement of volume retention rate after the second fat graft session (P < 0.001). Multivariate regression analysis showed that the interval time was an independent factor affecting the postoperative volume retention rate. The interval time between autologous fat transplantation for augmentation mammaplasty was an independent factor affecting the postoperative volume retention rate. The postoperative volume retention rate of the < 120 days group was higher than that of the ≥ 120 days group. 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 .

The histologic reaction and permanence of hyaluronic acid gel, calcium hydroxylapatite microspheres, and extracellular matrix bio gel.

The filling materials on the beauty market can be classified into three types: natural biological materials, synthetic polymer materials, and composites containing bioactive substances. However, comparative experimental data is lacking to compare their biological responses and permanence. The main object of this study was to evaluate the biological response of these three types of fillers to provide a theoretical basis for clinical application. Six-week-old female mice were injected subcutaneously with hyaluronic acid (HA) gel, calcium hydroxylapatite (CaHA) microspheres, and extracellular matrix (ECM) bio gel to observe the body reaction and permanence. At 1, 4, 8, and 16 weeks, the test sites were excised and analyzed by histopathology and proteomics. Extracellular matrix had a minimal foreign body response. HA had a good volume effect at the early stage but the volume retention rate was lower than CaHA in the long term. CaHA could stimulate neo-collagen formation. This study has proven the effectiveness and safety of these fillers and could provide clinical guidance for the plastic surgeon.

Deferoxamine Mesylate Improves the Survival Rate of Transplanted Fat by Promoting Angiogenesis.

The volume retention rate after autologous fat transplantation is unpredictable and unstable. Deferoxamine mesylate (DFO) is a drug approved by the FDA that is safe, has antioxidant effects, and can promote angiogenesis. The aim of this study was to transplant DFO-pretreated fat granules into nude mice to observe the proangiogenic effect of DFO and to evaluate whether this treatment could also improve the retention rate of fat transplantation. A total of 24 nude mice were transplanted with human adipose tissue that had been pretreated with different concentrations of DFO (0.5, 1, and 4 mM). Samples were collected at 1 and 3 months. After sampling, weight/volume retention rate, immunohistochemistry, and polymerase chain reaction were analyzed. The effects and mechanisms of DFO-pretreated fat grafts were evaluated. The in vivo experimental results showed that DFO-pretreated adipose fat significantly improved the postoperative weight/volume retention rate. The results of the immunohistochemical staining indicated that the integrity and activity of the adipocytes in the DFO-pretreated groups were better than in the control group. The polymerase chain reaction results were consistent with the immunohistochemistry results (CD31), suggesting that DFO promoted angiogenesis in the grafts. The results of this study indicate that preconditioning fat grafts with DFO can improve the effect of fat transplantation by promoting vascular regeneration.

Study on promoting the regeneration of grafted fat by cell-assisted lipotransfer

Cell-assisted lipotransfer (CAL), a modified adipose-derived stromal/stem cells (ADSCs)-based approach for autologous fat grafting that is an ideal option for soft tissue augmentation, has many shortcomings in terms of retention and adverse effects. The objective of our study was to improve the treatment efficacy of CAL by adding fibroblasts. ADSCs and fibroblasts were isolated from human adipose and dermal tissues, with fibroblasts identified by immunofluorescence and ADSCs identified by the multilineage differentiation method. We performed cell proliferation, apoptosis, migration, adipogenic, and hemangioendothelial differentiation experiments, qPCR and Western blotting analysis in co-cultures of fibroblasts and ADSCs. Subsequently, we conducted animal experiments with BALB/c nude mice. Masson's staining, immunofluorescence staining and ultrasound were used to analyze the occurrence of adverse reactions of the grafted fat, and CT and three-dimensional reconstruction were used to accurately evaluate the volume of the grafted fat. We found that the co-culture of fibroblasts and ADSCs promoted their mutual proliferation, adipogenic differentiation, hemangioendothelial differentiation and proliferation and migration of HUVECs. Fibroblasts inhibit the apoptosis of ADSCs. Moreover, in animal experiments, the autografted adipose group combined with ADSCs and fibroblasts had the least occurrence of oily cysts, and fat had the best form of survival. We enhanced adipocyte regeneration and angiogenesis in ADSCs and fibroblast cells after adding fibroblasts to conventional CAL autologous fat grafts. In turn, the volume retention rate of the grafted fat is improved, and the adverse reactions are reduced.

Three-dimensional Quantitative Standards for Assessing Outcomes of Facial Lipotransfer: A Review.

Reliable quantitative data are required to address the unpredictability of facial autologous fat grafting (AFG). Facial evaluation by 3D scanning technology is getting popular. However, this process lacks unified standards and the reliability assessments. This study aimed to summarize a set of standards to improve the 3D quantified reliability of AFG outcomes. A systematic review was used to collect the differences in and limitations of 3D assessments and analyze the effect of the quantification process on the AFG outcomes. Healthy subjects undergoing only one facial structural AFG and 3D assessments were included. The revealed specific issues guided the subsequent narrative review that involves 3D measurement and fat volume retention rate (FVRR) analysis. Criteria were formulated based on the narrative review. The systematic review revealed the quantitative process to be operator-dependent. The intra-group FVRR in the postoperative 11+ month group varied significantly (P=.03). The review identified a set of 3D measurement standards, including two optimal software products, two necessary steps for preprocessing, and four testing criteria. We proposed a new calculation formula and parameter and recommended a segmental area analysis for assessing the outcomes of full-face fat grafting. As far as the 3D evaluation of AFG outcomes is concerned, this is the first study to comprehensively analyze the process and set quantitative criteria. These standards would not only guide future research more reliably, but also provide fresh insight into the review of the past research. 3D measurement standards also apply to all face-related studies requiring 3D registration. 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 .

Increased Fat Graft Survival by Promoting Adipocyte Dedifferentiation.

Some adipocytes undergo dedifferentiation after fat transplantation, and this may affect the survival of fat grafts. However, this effect has not been adequately studied. This study aimed to clarify the effect of promoting the dedifferentiation of mature adipocytes on the survival of fat grafts. Mature adipocytes and adipose stem cells (ASCs) were treated with OSI-906 (a specific inhibitor of insulin receptor and insulin-like growth factor-1 receptor) in vitro, and then the dedifferentiation of mature adipocytes and the proliferation of ASCs were evaluated. In the in vivo experiment, human lipoaspirates mixed with phosphate-buffered saline (Group A) or OSI-906 (Group B) were compared in nude mice. Grafts were harvested at 2, 8, and 12 weeks, and volume retention rate, histologic, and immunohistochemical analyses were conducted. OSI-906 can promote the dedifferentiation of mature adipocytes and inhibit the proliferation of ASCs. At 12 weeks, Group B showed a better volume retention rate (mean [standard deviation, SD], 62.3% [7.61%]) than group A (47.75% [6.11%]) (P < .05). Moreover, viable adipocytes and vascularization showed greater improvement in Group B than in Group A. This study suggests that promoting the dedifferentiation of mature adipocytes can improve the survival rate and quality of fat grafts.

Viability and Stability of Various-Sized Free Diced Cartilage in an Experimental Study.

Historically, research of diced cartilage for rhinoplasty has mainly explored the efficacy of wrapped materials, with few studies dedicated to various sizes of diced cartilage. The authors of this study sought to evaluate the viability and stability of various-sized free diced cartilage. The remaining costal cartilage was harvested during rhinoplasties and implanted into subcutaneous pockets on the backs of nude mice: shaved cartilage (group A, n = 8), diced cartilage with a diameter <0.5 mm (group B, n = 8), 0.5 to 1.0 mm (group C, n = 8), and 1.0 to 1.5 mm (group D, n = 8). After 12 weeks, weight and volume retention rates, histopathological examinations, and biomechanical properties were evaluated. Cartilage grafts in groups A and B showed an obvious loss of contour and severe dispersion. The weight and volume of cartilage graft in group A were significantly decreased (all P < 0.05). Although there was no significant difference, group D (122.8 ± 15.4%) achieved the highest weight retention rate compared with groups B and C (114.6 ± 7.1% and 114.3 ± 10.1%, respectively). Group A showed the most apparent chondrocyte nucleus loss with the least peripheral proliferation, and group D showed the best regeneration potential (all P < 0.05). Group C achieved less chondrocyte nucleus loss than group B (P < 0.05). The compressive elastic modulus increased with the diameter of diced cartilage (all P < 0.05). Diced cartilage with a diameter of 1.0 to 1.5 mm may have the highest viability and stability, followed by those of 0.5 to 1.0 mm and <0.5 mm.

SVF-GEL Cryopreserved for Different Times Exhibits Varied Preservation and Regeneration Potential After Transplantation in a Mouse Model

BackgroundMatrix vascular component (SVF) gels derived from fat preserve tissue integrity and cell viability under cryopreserved conditions, making them easy to inject again for later use. Here, we compared the preservation power and regeneration potential of SVF-gel under different cryopreservation times.MethodsThe SVF-gel stored under − 20 °C, without cryoprotectant cryopreservation for 5, 15, and 45 days, with fresh SVF-gel as control. We evaluated the rate of volume retention after thawing the SVF-gel and the apoptosis rate of adipose-derived stem cells. Next, we analyzed retention rated, adipogenesis, angiogenesis, and connective tissue hyperplasia of the grafts, one month after subcutaneously transplanting the specimen into immunodeficient mice.ResultsSVF-gel cryopreserved for 5 and 15 days exhibited no significant different in apoptosis rates relative to the control group. Extending the cryopreservation time to 45 days resulted in significantly increased and decreased apoptosis and volume retention rates of SVF-gel, respectively. SVF-gel grafts cryopreserved for 5 and 15 days exhibited no significant differences from those in the control group, although their weights and volumes still fluctuated. Extending the cryopreservation time to 45 days resulted in significantly decreased retention rates of the grafts. Histologically, extending freezing time resulted in a gradual decline in the graft’s health adipose tissue, as well as decreased angiogenesis, and connective tissue hyperplasia.ConclusionSimple freezing of SVF-gel at − 20 °C conferred them with sufficient cell viability. Notably, short-term cryopreservation did not significantly increase the apoptosis rate, and it still had a certain regeneration after transplantation. However, prolonging freezing time to 45 days resulted in increased apoptosis rate and worsened transplantation effect.No Level AssignedThis 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.

294 Stem Cell Enriched Fat Grafts Versus Autologous Fat Grafts for Facial Reconstruction: A Systematic Review and Meta-Analysis

Abstract Aim To compare the results of stem cell-enhanced fat grafting to autologous fat grafting for face reconstruction. Method A systematic review and meta-analysis were carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines, and an electronic search was carried out to identify all Randomised Controlled Trials (RCTs), case control studies, and cohort studies comparing the outcomes of stem cell-enrichment fat grafting versus routine fat grafting for facial reconstruction. The primary outcome measures were volume retention and infection rate. Secondary outcome measures included post-surgery patient satisfaction, redness and swelling, fat necrosis, cysts, and operation time. For the analysis, fixed and random effects modelling were utilised. Results Eight studies with a total of 275 participants were assessed. In terms of mean volume retention, there was a significant difference between the stem cell-enrichment fat grafting and routine grafting groups (standardised Mean Difference [MD] = 2.49, P 0.00001). However, there was no significant difference in infection rates between the two groups (OR = 0.36, P = 0.30). Except for the operation duration, which was shorter in the latter, the intervention group had similar results to the control group for all secondary outcomes. Conclusions When compared to conventional fat grafting, stem cell-enriched fat grafting is a better alternative for facial reconstruction surgery since it enhances mean volume retention and does not worsen patient satisfaction or surgical complications.

O056 Achieving optimal clinical outcomes in autologous fat grafting (AFG): a systematic review of processing techniques

Abstract Introduction AFG is an increasingly popular technique in reconstructive and cosmetic surgery but significant variability in long-term graft retention continues to be a limitation. This results in unreliable clinical outcomes and revision procedures. There is no consensus on the optimal methodology of graft processing. This systematic review identifies the latest evidence base supporting different processing techniques. Methods A systematic literature search was conducted using PubMed, SCOPUS, and the Cochrane electronic databases. Studies comparing AFG processing techniques and reporting long-term patient outcomes (≥3 months) were identified. Data collected included the technical aspects of techniques, cohort characteristics, complication rates, volume retention. Systematic assessment of study quality was also performed. Results Twenty-four studies (2928 patients) providing at least level three evidence were included. Processing techniques evaluated included centrifugation, decantation, washing, filtration, gauze rolling, as well as commercial devices and ASC enrichment methods. There was variable reporting of complications and volume retention rates. Complications were infrequent; palpable cysts (0–18%), cellulitis (0–8%) and fat necrosis (0–36.4%) were the most commonly reported. No significant differences in long-term volume retention between techniques were found in AFG in the breast. In head and neck patients, greater volume retention were documented in ASC enrichment (64.8–95.8%) and commercial devices (41.2%) compared to centrifugation (31.8–76%). Conclusion The quality of AFG research has improved significantly in recent years but has heterogeneity in reporting outcomes. ASC (adipose derived stem/stromal cells) enrichment methods and commercial devices results in superior long-term volume retention in facial but not breast fat grafting. Take-home message Adipose derived stem/stromal cell enrichment methods and commercial devices have superior long term volume retention in facial but not breast autologous fat grafting [level of evidence II]. Randomised control trials are necessary to identify if certain processing methods are superior to others in volume retention and complication rates.