The Impact of N-Acetylcysteine on Autologous Fat Graft: First-in-Human Pilot Study

Improving Fat Graft Survival Using Soluble Molecule Preconditioning

Fat grafting is widely used in plastic surgery to correct soft tissue deformities. A major limitation of this technique is the poor long-term volume retention of the injected fat due to tissue remodeling and adipocyte death. To address this issue, various optimizations of the grafting process have been proposed. This scoping review focuses on preclinical and clinical studies that investigated the impact of various classes of soluble molecules on fat grafting outcomes. Globally, we describe that these molecules can be classified as acting through three main mechanisms to improve graft retention: supporting adipogenesis, improving vascularization, and reducing oxidative stress. A variety of 18 molecules are discussed, including insulin, VEGF, deferoxamine, botulinum toxin A, apocynin, N-acetylcysteine, and melatonin. Many biomolecules have shown the potential to improve long-term outcomes of fat grafts through enhanced cell survival and higher volume retention. However, the variability between experimental protocols, as well as the scarcity of clinical studies, remain obstacles to clinical translation. In order to determine the best preconditioning method for fat grafts, future studies should focus on dosage optimization, more sustained delivery of the molecules, and the design of homogenous experimental protocols and specific clinical trials.

Large Fibrous Connective Tissue Reduces Oxidative Stress to Form a Living Cell Scaffold in Adipose Grafts

This study aimed to investigate the mechanisms by which large fibrous connective (LFC) tissue enhances fat graft survival in fat transplantation. A block fat graft model demonstrated that intact fat containing LFC showed significantly higher survival rates compared with liposuctioned fat. In the center of intact grafts, viable fat cells surrounded the LFC, forming a mesh-like living tissue structure. Proteomics of the extracellular matrix (ECM) adjacent to LFC (ALFC) and distant to LFC (DLFC) revealed significant differences in mitochondrial aspects. Staining of LFC tissue showed that it contains a large number of blood vessels and mitochondria, and exhibits stronger antioxidant capacity (p < 0.05) compared with adipose tissue. By mixing LFC with liposuctioned fat and transplanting into nude mice, histological sections showed that LFC promotes SOD1 expression, enhances respiratory chain RNA expression, and reduces ROS and inflammation. Pure mitochondrial-assisted fat transplantation only reduced short-term graft inflammation without improving long-term survival rates. In conclusion, LFC enhances long-term survival rates by reducing oxidative stress in fat grafts and forming a center for fat cell survival, thereby overcoming distance limitations. This represents a novel mechanism distinct from classical fat survival models and provides a reference for clinical practice.

Oral Administration of Lutein Improves Fat Graft Survival by Alleviating Oxidative Stress in Mice

BACKGROUND

Oxidative stress induced by ischemia and hypoxia in fat transplantation is a major obstacle to graft retention. Previous studies have shown that lutein has excellent adipose tissue affinity and antioxidative stress ability, however, the effects of oral lutein on fat transplantation have not yet been studied.

OBJECTIVES

We aimed to investigate whether oral lutein could improve fat transplantation retention by regulating oxidative stress, apoptosis, and inflammatory cytokine levels in graft tissues.

METHODS

Nude mice were assigned to the control group (normal saline), low-dose lutein group (10 mg/kg/day), and high-dose lutein group (20 mg/kg/day) randomly. All mice received treatment by gavage 1 week before fat grafting and continued for 2 weeks. The grafts were collected 1, 2, and 12 weeks after treatment. By conducting histological analyses, Western blotting, quantitative polymerase chain reaction and cell metabolic function detection, the regulatory effects of lutein on apoptosis and oxidative stress in grafts were demonstrated. Additionally, RNA sequencing was conducted to further clarify the efficacy of lutein on fat grafting.

RESULTS

Lutein induced superior graft retention, histological structures, and more viable adipocytes than the control group. It relieved tissue oxidative stress and lipid oxidative damage by decreasing reactive oxygen species and significantly reduced inflammation and apoptosis of grafts. RNA sequencing analysis confirmed that lutein could downregulate the gene expression of oxidative stress and related inflammation and apoptosis.

CONCLUSIONS

Our study suggests that oral administration of lutein can improve fat graft survival by reducing the levels of oxidative stress, inflammation, and apoptosis in grafted fat.

Integrating Radioprotective Agents into Post-Mastectomy Radiotherapy: Optimization of Reconstructive Outcomes in Breast Cancer

Surgical intervention utilizing various approaches is a cornerstone in the management of breast cancer. The surgical approaches include lumpectomy, mastectomy, axillary lymph node dissection, and primary or delayed reconstruction. Post-mastectomy radiotherapy is frequently recommended in cases of advanced tumors and extensive lymph node involvement. However, there are several adverse effects of radiotherapy. In this article, we critically reviewed the various complications. Additionally, we discussed the biological basis of radiation-induced tissue damage, the impact of implant-based and autologous tissue reconstruction, and the functional and aesthetic results of the reconstruction. Indeed, several radioprotective agents can attenuate the adverse effects of post-mastectomy radiotherapy while sustaining oncologic efficacy. Radioprotective agents, including free radical scavengers and antioxidants, offer promising strategies to protect tissues from the oxidative stress and inflammation induced by radiotherapy. The role of several radioprotective agents, including amifostine, N-acetylcysteine, tempol, manganese superoxide dismutase (MnSOD) plasmid liposomes, vitamin E, and beta-carotene has been analyzed with a focus on their logistical applications in breast reconstruction. Despite several challenges, the integration of radioprotective agents into post-mastectomy radiotherapy protocols offers significant potential to improve reconstructive outcomes. Development of novel radioprotective agents with improved selectivity and fewer side effects and large-scale clinical trials in diverse group of patients are warranted to determine long-term safety and efficacy.

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

INTRODUCTION

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.

METHODS

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.

CONCLUSION

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.

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.

Hydrogen-Generating Silicon-Based Agent Improves Fat Graft Survival in Rats

BACKGROUND

Regulating excessive inflammation and oxidative stress in fat grafting may improve retention rates. Hydrogen effectively combats oxidative stress and inflammation and reportedly inhibits ischemia-reperfusion injury in various organs. However, with conventional methods of hydrogen administration, incorporating hydrogen continuously into the body over a long period of time is difficult. The authors hypothesized that a silicon (Si)-based agent they recently developed would aid in fat grafting, as it can generate large amounts of hydrogen continuously in the body.

METHODS

Fat grafting was performed on the backs of rats fed either a normal or 1.0 wt% Si-based agent-containing diet. To investigate synergistic effects with adipose-derived stromal cells (ASCs), which improve retention rates of fat grafting, fat grafting with ASCs (1.0 × 10 5 /400 mg fat) was also performed in each rat. Postoperative retention rates of grafted fat over time, inflammatory indices, apoptosis, oxidative stress markers, histologic findings, and expression levels of inflammation-related cytokines and growth factors were compared among the 4 groups.

RESULTS

Intake of Si-based agent and addition of ASCs significantly reduced inflammatory indices, oxidative stress, and apoptosis of grafted fat, and improved long-term retention rates, histologic measures, and grafted fat quality. Under the experimental conditions, intake of the Si-based agent and addition of ASCs yielded comparable improvements in fat graft retention. Combining the 2 enhanced these effects.

CONCLUSIONS

Oral administration of a hydrogen-generating Si-based agent may improve grafted fat retention by regulating the inflammatory response and oxidative stress in grafted fat.

CLINICAL RELEVANCE STATEMENT

This study demonstrates improved grafted fat retention rates using a Si-based agent. This Si-based agent has the potential to expand the range of therapeutic indications of hydrogen-based therapy to conditions for which hydrogen has yet to be found effective, such as fat grafting.

Glutathione supplementation improves fat graft survival by inhibiting ferroptosis via the SLC7A11/GPX4 axis

BACKGROUND

Autologous fat grafting is hampered by unpredictable graft survival, which is potentially regulated by ferroptosis. Glutathione (GSH), a powerful antioxidant used in tissue preservation, has ferroptosis-regulating activity; however, its effects on fat grafts are unclear. This study investigated the effects and mechanisms of GSH in fat graft survival.

METHODS

Human lipoaspirates were transplanted subcutaneously into the backs of normal saline-treated (control) or GSH-treated nude mice. Graft survival was evaluated by magnetic resonance imaging and histology. RNA sequencing was performed to identify differentially expressed genes and enriched pathways. GSH activity was evaluated in vitro using an oxygen and glucose deprivation (OGD) model of adipose-derived stem cells.

RESULTS

Compared with control group, GSH induced better outcomes, including superior graft retention, appearance, and histological structures. RNA sequencing suggested enhanced negative regulation of ferroptosis in the GSH-treated grafts, which showed reduced lipid peroxides, better mitochondrial ultrastructure, and SLC7A11/GPX4 axis activation. In vitro, OGD-induced ferroptosis was ameliorated by GSH, which restored cell proliferation, reduced oxidative stress, and upregulated ferroptosis defense factors.

CONCLUSIONS

Our study confirms that ferroptosis participates in regulating fat graft survival and that GSH exerts a protective effect by inhibiting ferroptosis. GSH-assisted lipotransfer is a promising therapeutic strategy for future clinical application.

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

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

PQQ could improve the long-term survival of adipocytes by alleviating hypoxic stress and promoting timely angiogenesis in the early phase following lipotransfer.

LEVEL OF EVIDENCE: 4

Therapeutic potential of adipose tissue-derivatives in modern dermatology

Stem cell-mediated therapies in combination with biomaterial and growth factor-based approaches in regenerative medicine are rapidly evolving with increasing application beyond the dermatologic field. Adipose-derived stem cells (ADSCs) are the more frequently used adult stem cells due to their abundance and easy access. In the case of volumetric defects, adipose tissue can take the shape of defects, restoring the volume and enhancing the regeneration of receiving tissue. When regenerative purposes prevail on volume restoration, the stromal vascular fraction (SVF) rich in staminal cells, purified mesenchymal stem cells (MSCs) or their cell-free derivatives grafting are favoured. The therapeutic efficacy of acellular approaches is explained by the fact that a significant part of the natural propensity of stem cells to repair damaged tissue is ascribable to their secretory activity that combines mitogenic factors, cytokines, chemokines and extracellular matrix components. Therefore, the secretome's ability to modulate multiple targets simultaneously demonstrated preclinical and clinical efficacy in reversing pathological mechanisms of complex conditions such atopic dermatitis (AD), vitiligo, psoriasis, acne and Lichen sclerosus (LS), non-resolving wounds and alopecia. This review analysing both in vivo and in vitro models gives an overview of the clinical relevance of adipose tissue-derivatives such as autologous fat graft, stromal vascular fraction, purified stem cells and secretome for skin disorders application. Finally, we highlighted the major disease-specific limitations and the future perspective in this field.

Hyperbaric Oxygen Improves the Survival and Angiogenesis of Fat Grafts after Autologous Fat Transplantation

Objective

Currently, autologous fat transplantation (AFT) still has a low graft survival rate. Elevation of the AFT graft survival rate is a challenge. This study investigated the effect of hyperbaric oxygen (HBO) on AFT.

Methods

Twelve adult male SD rats were randomly divided into two groups after AFT: the control group (n = 6) and the HBO group (n = 6). The rats were killed at 7, 14, and 28 days after transplantation to take the transplanted adipose tissues. The volume and weight of the tissues were detected. The pathological changes in the adipose tissues were observed after H&E staining. Microvessel density and levels of transforming growth factor- (TGF-) β, tumor necrosis factor- (TNF-) α, and malondialdehyde (MDA) in the transplanted adipose tissues were measured with CD31 immunohistochemical stain, ELISA, and biochemical reagents, respectively. Additionally, the protein expression levels of vascular endothelial growth factor- (VEGF-) A and platelet-derived growth factor- (PDGF) A in the adipose tissues were detected by Western blot.

Results

HBO significantly preserved the volume and weight of the transplanted adipose tissue (p < 0.01) and maintained the pathological structure of the transplanted adipose tissue. HBO therapy was effective in reducing inflammatory factor (TGF-β and TNF-α) levels and oxidative stress (MDA) in the transplanted adipose tissue (p < 0.01) and significantly increased the level of CD31 and angiogenesis-related factors including VEGF-A and PDGF-A (p < 0.01) to promote angiogenesis.

Conclusion

HBO therapy regulated the immune response of fat grafts, stimulated their angiogenesis, and ultimately promoted their survival after AFT.

New perspectives in regenerative medicine and surgery: the bioactive composite therapies (BACTs)

Regenerative medicine and surgery is a rapidly expanding branch of translational research in tissue engineering, cellular and molecular biology. To date, the methods to improve cell intake, survival, and isolation need to comply with a complex and still unclear regulatory frame, becoming everyday more restrictive and often limiting the effectiveness and outcome of the therapeutic choices. Thus, the authors developed a novel 360° regenerative strategy based on the synergic action of several new components called the bioactive composite therapies (BACTs) to improve grafted cells intake, and survival in total compliance with the legal and ethical limits of the current regulatory frame. The rationale at the origin of this new technology is based on the evidence that cells need supportive substrate to survive in vitro and this observation, applying the concept of translational medicine, is true also in vivo. Bioactive composite mixtures (BACMs) are tailor-made bioactive mixtures containing several bioactive components that support cells' survival and induce a regenerative response in vivo by stimulating the recipient site to act as an in situ real bioreactor. Many different tissues have been used in the past for the isolation of cells, molecules, and growth factors, but the adipose tissue and its stromal vascular fraction (SVF) remains the most valuable, abundant, safe, and reliable source of regenerative components and particularly of adipose-derived stems cells (ADSCs). The role of plastic surgeons as the historical experts in all the most advanced techniques for harvesting, manipulating, and grafting adipose tissue is fundamental in this constant process of expansion of regenerative procedures. In this article, we analyze the main causes of cell death and the strategies for preventing it, and we present all the technical steps for preparing the main components of BACMs and the different mixing modalities to obtain the most efficient regenerative action on different clinical and pathological conditions. The second section of this work is dedicated to the logical and sequential evolution from simple bioactive composite grafts (BACGs) that distinguished our initial approach to regenerative medicine, to BACTs where many other fundamental technical steps are analyzed and integrated for supporting and enhancing the most efficient regenerative activity. Level of Evidence: Not gradable.

Single Dose of N-Acetylcysteine in Local Anesthesia Increases Expression of HIF1α, MAPK1, TGFβ1 and Growth Factors in Rat Wound Healing

In this study, we aimed to investigate the influence of N-acetylcysteine (NAC) on the gene expression profile, neoangiogenesis, neutrophils and macrophages in a rat model of incisional wounds. Before creating wounds on the backs of 24 Sprague-Dawley rats, intradermal injections were made. Lidocaine-epinephrin solutions were supplemented with 0.015%, 0.03% or 0.045% solutions of NAC, or nothing (control group). Scars were harvested on the 3rd, 7th, 14th and 60th day post-surgery. We performed immunohistochemical staining in order to visualize macrophages (anti-CD68), neutrophils (anti-MPO) and newly formed blood vessels (anti-CD31). Additionally, RT-qPCR was used to measure the relative expression of 88 genes involved in the wound healing process. On the 14th day, the number of cells stained with anti-CD68 and anti-CD31 antibodies was significantly larger in the tissues treated with 0.03% NAC compared with the control. Among the selected genes, 52 were upregulated and six were downregulated at different time points. Interestingly, NAC exerted a significant effect on the expression of 45 genes 60 days after its administration. In summation, a 0.03% NAC addition to the pre-incisional anesthetic solution improves neovasculature and increases the macrophages' concentration at the wound site on the 14th day, as well as altering the expression of numerous genes that are responsible for the regenerative processes.