Evaluation of the efficacy of lipotransfer to manage radiation-induced fibrosis and volume defects in head and neck oncology

Exploring Anti-Fibrotic Effects of Adipose-Derived Stem Cells: Transcriptome Analysis upon Fibrotic, Inflammatory, and Hypoxic Conditioning

Autologous fat transfers show promise in treating fibrotic skin diseases, reversing scarring and stiffness, and improving quality of life. Adipose-derived stem cells (ADSCs) within these grafts are believed to be crucial for this effect, particularly their secreted factors, though the specific mechanisms remain unclear. This study investigates transcriptomic changes in ADSCs after in vitro fibrotic, inflammatory, and hypoxic conditioning. High-throughput gene expression assays were conducted on ADSCs exposed to IL1-β, TGF-β1, and hypoxia and in media with fetal bovine serum (FBS). Flow cytometry characterized the ADSCs. RNA-Seq analysis revealed distinct gene expression patterns between the conditions. FBS upregulated pathways were related to the cell cycle, replication, wound healing, and ossification. IL1-β induced immunomodulatory pathways, including granulocyte chemotaxis and cytokine production. TGF-β1 treatment upregulated wound healing and muscle tissue development pathways. Hypoxia led to the downregulation of mitochondria and cellular activity.

Scarring and Skin Fibrosis Reversal with Regenerative Surgery and Stem Cell Therapy

Skin scarring and fibrosis affect millions of people worldwide, representing a serious clinical problem causing physical and psychological challenges for patients. Stem cell therapy and regenerative surgery represent a new area of treatment focused on promoting the body's natural ability to repair damaged tissue. Adipose-derived stem cells (ASCs) represent an optimal choice for practical regenerative medicine due to their abundance, autologous tissue origin, non-immunogenicity, and ease of access with minimal morbidity for patients. This review of the literature explores the current body of evidence around the use of ASCs-based regenerative strategies for the treatment of scarring and skin fibrosis, exploring the different surgical approaches and their application in multiple fibrotic skin conditions. Human, animal, and in vitro studies demonstrate that ASCs present potentialities in modifying scar tissue and fibrosis by suppressing extracellular matrix (ECM) synthesis and promoting the degradation of their constituents. Through softening skin fibrosis, function and overall quality of life may be considerably enhanced in different patient cohorts presenting with scar-related symptoms. The use of stem cell therapies for skin scar repair and regeneration represents a paradigm shift, offering potential alternative therapeutic avenues for fibrosis, a condition that currently lacks a cure.

Exploring the mechanisms behind autologous lipotransfer for radiation-induced fibrosis: A systematic review

AIM

Radiation-induced fibrosis is a recognised consequence of radiotherapy, especially after multiple and prolonged dosing regimens. There is no definitive treatment for late-stage radiation-induced fibrosis, although the use of autologous fat transfer has shown promise. However, the exact mechanisms by which this improves radiation-induced fibrosis remain poorly understood. We aim to explore existing literature on the effects of autologous fat transfer on both in-vitro and in-vivo radiation-induced fibrosis models, and to collate potential mechanisms of action.

METHOD

PubMed, Cochrane reviews and Scopus electronic databases from inception to May 2023 were searched. Our search strategy combined both free-text terms with Boolean operators, derived from synonyms of adipose tissue and radiation-induced fibrosis.

RESULTS

The search strategy produced 2909 articles. Of these, 90 underwent full-text review for eligibility, yielding 31 for final analysis. Nine conducted in-vitro experiments utilising a co-culture model, whilst 25 conducted in-vivo experiments. Interventions under autologous fat transfer included adipose-derived stem cells, stromal vascular function, whole fat and microfat. Notable findings include downregulation of fibroblast proliferation, collagen deposition, epithelial cell apoptosis, and proinflammatory processes. Autologous fat transfer suppressed hypoxia and pro-inflammatory interferon-γ signalling pathways, and tissue treated with adipose-derived stem cells stained strongly for anti-inflammatory M2 macrophages. Although largely proangiogenic initially, studies show varying effects on vascularisation. There is early evidence that adipose-derived stem cell subgroups may have different functional properties.

CONCLUSION

Autologous fat transfer functions through pro-angiogenic, anti-fibrotic, immunomodulatory, and extracellular matrix remodelling properties. By characterising these mechanisms, relevant drug targets can be identified and used to further improve clinical outcomes in radiation-induced fibrosis. Further research should focus on adipose-derived stem cell sub-populations and augmentation techniques such as cell-assisted lipotransfer.

Autologous Fat Grafting for Functional and Aesthetic Improvement in Patients with Head and Neck Cancer: A Systematic Review

INTRODUCTION

The efficacy and safety of autologous fat grafting for use in oncology patients are controversial. Patients with head and neck cancer have complex anatomy and require reconstructive repair of the head and neck after comprehensive treatment. The limited additional aesthetic and functional studies on the use of autologous fat fillers in patients with head and neck cancer are unclear. This study systematically evaluates the additional function of autologous fat fillers in the head and neck and systematically reviews issues related to autologous fat grafting after comprehensive head and neck cancer treatment, including current indications, techniques, potential complications, graft survival, and patient satisfaction.

METHODS

A systematic literature review was performed using PubMed, The Cochrane Library, EMBASE, and Web of Science (last accessed on January 9, 2023).

RESULTS

A total of 249 cases of autologous fat fillers in patients with head and neck cancer were reported in 10 clinical publications. Observations were based mainly on subjective physician and patient evaluation indicators, and all studies reported the beneficial effects of autologous fat fillers on aesthetics and function after treatment for head and neck cancer.

CONCLUSIONS

Autologous fat fillers are effective in improving the aesthetics and function of head and neck cancer, and due to the limitations of the original study, future studies with large samples are needed to support this. PROSPERO registration number is CRD42020222870.

LEVEL OF EVIDENCE III

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 .

Single-Cell Analysis of ADSC Interactions with Fibroblasts and Endothelial Cells in Scleroderma Skin

Adipose-derived stem cells (ADSCs) as part of autologous fat grafting have anti-fibrotic and anti-inflammatory effects, but the exact mechanisms of action remain unknown. By simulating the interaction of ADSCs with fibroblasts and endothelial cells (EC) from scleroderma (SSc) skin in silico, we aim to unravel these mechanisms. Publicly available single-cell RNA sequencing data from the stromal vascular fraction of 3 lean patients and biopsies from the skin of 10 control and 12 patients with SSc were obtained from the GEO and analysed using R and Seurat. Differentially expressed genes were used to compare the fibroblast and EC transcriptome between controls and SSc. GO and KEGG functional enrichment was performed. Ligand-receptor interactions of ADSCs with fibroblasts and ECs were explored with LIANA. Pro-inflammatory and extracellular matrix (ECM) interacting fibroblasts were identified in SSc. Arterial, capillary, venous and lymphatic ECs showed a pro-fibrotic and pro-inflammatory transcriptome. Most interactions with both cell types were based on ECM proteins. Differential interactions identified included NTN1, VEGFD, MMP2, FGF2, and FNDC5. The ADSC secretome may disrupt vascular and perivascular inflammation hubs in scleroderma by promoting angiogenesis and especially lymphangiogenesis. Key phenomena observed after fat grafting remain unexplained, including modulation of fibroblast behaviour.

Outcomes Following Autologous Fat Grafting in Patients with Sequelae of Head and Neck Cancer Treatment

A single-center retrospective study was designed to assess the outcomes of autologous fat grafting for improving surgery- and radiotherapy-related sequelae in 40 patients with head and neck cancer. All patients underwent surgical resection of primary tumors and radiotherapy (50-70 Gy) and were followed over 12 months after fat grafting. Eligibility for fat grafting procedures included complete remission after at least 3 years of oncological treatment. The cervical and paramandibular regions were the most frequently treated areas. Injected fat volumes ranged between 7.5 and 120 mL (mean: 23 mL). Esthetic improvement was obtained in 77.5% of patients, being significant in 17.5%, and functional improvement in 89.2%, being significant in 29.7% of patients. Minor complications occurred in three patients. There was a high degree of satisfaction regarding esthetic improvement, global satisfaction, and 92.5% of patients would recommend the procedure. This study confirms the benefits of fat grafting as a volumetric correction reconstructive strategy with successful cosmetic and functional outcomes in patients suffering from sequelae after head and neck cancer treatment.

Decellularized Adipose Matrices Can Alleviate Radiation-Induced Skin Fibrosis

Objective: Radiation therapy is commonplace for cancer treatment but often results in fibrosis and atrophy of surrounding soft tissue. Decellularized adipose matrices (DAMs) have been reported to improve these soft tissue defects through the promotion of adipogenesis. These matrices are decellularized by a combination of physical, chemical, and enzymatic methods to minimize their immunologic effects while promoting their regenerative effects. In this study, we aimed at exploring the regenerative ability of a DAM (renuva®; MTF biologics, Edison, NJ) in radiation-induced soft tissue injury. Approach: Fresh human lipoaspirate or DAM was injected into the irradiated scalp of CD-1 nude mice, and volume retention was monitored radiographically over 8 weeks. Explanted grafts were histologically assessed, and overlying skin was examined histologically and biomechanically. Irradiated human skin was also evaluated from patients after fat grafting or DAM injection. However, integrating data between murine and human skin in all cohorts is limited given the genetic variability between the two species. Results: Volume retention was found to be greater with fat grafts, though DAM retention was, nonetheless, appreciated at irradiated sites. Improvement in both mouse and human irradiated skin overlying fat and DAM grafts was observed in terms of biomechanical stiffness, dermal thickness, collagen density, collagen fiber networks, and skin vascularity. Innovation: This is the first demonstration of the use of DAMs for augmenting the regenerative potential of irradiated mouse and human skin. Conclusions: These findings support the use of DAMs to address soft tissue atrophy after radiation therapy. Morphological characteristics of the irradiated skin can also be improved with DAM grafting.

Noninvasive Systemic Modalities for Prevention of Head and Neck Radiation-Associated Soft Tissue Injury: A Narrative Review

BACKGROUND

 Radiation-associated soft tissue injury is a potentially devastating complication for head and neck cancer patients. The damage can range from minor sequelae such as xerostomia, which requires frequent daily maintenance, to destructive degenerative processes such as osteoradionecrosis, which can contribute to flap failure and delay or reverse oral rehabilitation. Despite the need for effective radioprotectants, the literature remains sparse, primarily focused on interventions beyond the surgeon's control, such as maintenance of good oral hygiene or modulation of radiation dose.

METHODS

 This narrative review aggregates and explores noninvasive, systemic treatment modalities for prevention or amelioration of radiation-associated soft tissue injury.

RESULTS

 We highlighted nine modalities with the most clinical potential, which include amifostine, melatonin, palifermin, hyperbaric oxygen therapy, photobiomodulation, pentoxifylline-tocopherol-clodronate, pravastatin, transforming growth factor-β modulators, and deferoxamine, and reviewed the benefits and limitations of each modality. Unfortunately, none of these modalities are supported by strong evidence for prophylaxis against radiation-associated soft tissue injury.

CONCLUSION

 While we cannot endorse any of these nine modalities for immediate clinical use, they may prove fruitful areas for further investigation.

Autologous Craniofacial Fat Grafting in the Irradiated Field

ABSTRACT

Autologous fat grafting has been used as a reconstructive modality following the treatment of head and neck malignancy. However, it has been criticized for poor graft retention and unpredictable results, which may be further compromised by prior radiation therapy. This systematic review will consolidate the literature on autologous fat grafting in the previously irradiated craniofacial region and report its effects on aesthetic and functional outcomes, volume resorption, and postoperative complications. A computerized search of Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, and Web of Science was performed. Screening and data extraction were performed in duplicate. Data were extracted from the included articles, and outcomes were analyzed categorically. Sixty patients from six studies were included. Mean age was 46.06 years (range 13-73) and 37.5% were female. All studies used the Coleman technique fat grafting or a modified version. A total of 94.9% of patients had significant improvement in aesthetic outcomes and 86.1% in the study specific functional outcomes. Mean graft volume resorption was 41% (range 20%-62%) and there were three (5%) postoperative complications. Autologous fat grafting is increasingly being used to optimize aesthetic outcome following head and neck reconstruction, even in the presence of prior radiation treatment. Although the literature to date is encouraging, the heterogeneity in patient population, intervention, outcome measures, and time horizon limit our ability to draw conclusions about the success of craniofacial fat grafting in the irradiated field. Future research should include a large comparative study as well as a protocol for standardizing outcome measures in this population.

Regenerative Strategy for Persistent Periprosthetic Leakage around Tracheoesophageal Puncture: Is It an Effective Long-Term Solution?

Autologous tissue-assisted regenerative procedures have been considered effective to close different types of fistula, including the leakage around tracheoesophageal puncture. The aim of this study was to retrospectively review 10 years of lipotransfer for persistent periprosthetic leakage in laryngectomized patients with voice prosthesis. Clinical records of patients who experienced periprosthetic leakage from December 2009 to December 2019 were reviewed. Patients receiving fat grafting were included. The leakage around the prosthesis was assessed with a methylene blue test. Twenty patients experiencing tracheoesophageal fistula enlargement were treated with fat grafting. At the one-month follow-up, all patients were considered improved with no leakage observed. At six months, a single injection was sufficient to solve 75% of cases (n 15), whereas 25% (n 5) required a second procedure. The overall success rate was 80% (n 16). Results remained stable for a follow-up of 5.54 ± 3.97 years. Fat grafting performed around the voice prosthesis, thanks to its volumetric and regenerative properties, is a valid and lasting option to solve persistent periprosthetic leakage.

Fat Grafting Improves Fibrosis and Scarring in Vulvar Lichen Sclerosus: Results From a Prospective Cohort Study

OBJECTIVE

The aim of the study was to evaluate the effect of lipotransfer in women presenting with fibrosis and scarring due to lichen sclerosus.

MATERIALS AND METHODS

This prospective cohort study included 33 women attending the vulvar clinic of a public hospital. Patients received one lipotransfer treatment. Validated measures were used prospectively to assess the sexual function (Female Sexual Function Index, Female Sexual Distress Scale); symptoms (visual analog scale for itching, burning, soreness), pain (Pain Anxiety Symptoms Scale 20); psychological status and quality of life (Hospital Anxiety and Depression Scale, Relationship Assessment Scale, Wound Management Questionnaire Revised); physician-based disease signs (Vulvar Architecture Severity Scale). Data were analyzed using paired t test with nonparametric Wilcoxon matched-pairs signed rank test and unpaired t test with nonparametric Mann-Whitney test (Prism6 Software).

RESULTS

The mean (SD) follow-up was 12.9 (3.5) months. Sexual function improved after treatment (p < .001), as well as the distress associated with sexuality (p < .0001). A significant improvement was reported in itching (p < .001), burning (p < .05), soreness (p < .001), and pain (p < .0001). Patients reported a significant improvement in romantic relationship (p < .05), anxiety (p < .0001), and depression (p < .0001). Improvement was not significant in the self-care associated with self-disgust assessment (p = .42). The clinical physician-based score showed an overall improvement in all the treated areas to lesser or greater extent.

CONCLUSIONS

The use of fat grafting in lichen sclerosus is promising. Further studies are required to rule out a potential placebo effect and to better understand the underlying molecular mechanism of action.

Regenerative medicine approaches for the management of respiratory tract fistulas

Respiratory tract fistulas (or fistulae) are abnormal communications between the respiratory system and the digestive tract or the adjacent organs. The origin can be congenital or, more frequently, iatrogenic and the clinical presentation is heterogeneous. Respiratory tract fistulas can lead to severely reduced health-related quality of life and short survival. Therapy mainly relies on endoscopic surgical interventions but patients often require prolonged hospitalization and may develop complications. Therefore, more conservative regenerative medicine approaches, mainly based on lipotransfer, have also been investigated. Adipose tissue can be delivered either as unprocessed tissue, or after enzymatic treatment to derive the cellular stromal vascular fraction. In the current narrative review, we provide an overview of the main tissue/cell-based clinical studies for the management of various types of respiratory tract fistulas or injuries. Clinical experience is limited, as most of the studies were performed on a small number of patients. Albeit a conclusive proof of efficacy cannot be drawn, the reviewed studies suggest that grafting of adipose tissue-derived material may represent a minimally invasive and conservative treatment option, alternative to more aggressive surgical procedures. Knowledge on safety and tolerability acquired in prior studies can lead to the design of future, larger trials that may exploit innovative procedures for tissue processing to further improve the clinical outcome.

Prophylactic treatment with transdermal deferoxamine mitigates radiation-induced skin fibrosis

Radiation therapy can result in pathological fibrosis of healthy soft tissue. The iron chelator deferoxamine (DFO) has been shown to improve skin vascularization when injected into radiated tissue prior to fat grafting. Here, we evaluated whether topical DFO administration using a transdermal drug delivery system prior to and immediately following irradiation (IR) can mitigate the chronic effects of radiation damage to the skin. CD-1 nude immunodeficient mice were split into four experimental groups: (1) IR alone (IR only), (2) DFO treatment for two weeks after recovery from IR (DFO post-IR), (3) DFO prophylaxis with treatment through and post-IR (DFO ppx), or (4) no irradiation or DFO (No IR). Immediately following IR, reactive oxygen species and apoptotic markers were significantly decreased and laser doppler analysis revealed significantly improved skin perfusion in mice receiving prophylactic DFO. Six weeks following IR, mice in the DFO post-IR and DFO ppx groups had improved skin perfusion and increased vascularization. DFO-treated groups also had evidence of reduced dermal thickness and collagen fiber network organization akin to non-irradiated skin. Thus, transdermal delivery of DFO improves tissue perfusion and mitigates chronic radiation-induced skin fibrosis, highlighting a potential role for DFO in the treatment of oncological patients.