Molecular Characterization of Lipoaspirates Used in Regenerative Head and Neck Surgery

Pilot Study for Isolation of Stromal Vascular Fraction with Collagenase Using an Automated Processing System

There are many potential therapeutic applications for autologous adipose-derived stromal cells. These cells are found in a heterogeneous population isolated from adipose tissue called the stromal vascular fraction (SVF). Closed automated systems are available to release cells from the adherent stroma. Here, we test one system to evaluate the heterogeneous output for yield, purity, cellular characterization, and stemness criteria. The SVF was isolated from three donors using the Automated Cell Station (ACS) from BSL Co., Ltd., Busan, Republic of Korea. The SVF cellular output was characterized for cell yield and viability, immunophenotyping analysis, pluripotent differentiation potential, adhesion to plastic, and colony-forming units. Additionally, the SVF was tested for endotoxin and collagenase residuals. The SVF yield from the ACS system was an average volume of 7.9 ± 0.5 mL containing an average of 19 × 106 nucleated cells with 85 ± 12% viability. Flow cytometry identified a variety of cells, including ASCs (23%), macrophages (24%), endothelial cells (5%), pericytes (4%), and transitional cells (0.5%). The final concentrated product contained cells capable of differentiating into adipogenic, chondrogenic, and osteogenic phenotypes. Furthermore, tests for SVF sterility and purity showed no evidence of endotoxin or collagenase residuals. The ACS system can efficiently process cells from adipose tissue within the timeframe of a single surgical procedure. The cellular characterization indicated that this system can yield a sterile and concentrated SVF output, providing a valuable source of ASCs within the heterogeneous cell population.

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 .

Free Flap Fat Volume is Not Associated With Recurrence or Wound Complications in Oral Cancer

Objective

Adipose stem cells (ASCs) have been shown in many preclinical studies to be potent suppressors of the immune system. Prior studies suggest that ASCs may promote cancer progression and wound healing. However, clinical studies investigating the effects of native, or fat-grafted adipose tissue on cancer recurrence have generated mixed results. We investigated whether adipose content in reconstructive free flaps for oral squamous cell carcinoma (OSCC) is associated with disease recurrence and/or reduction in wound complications.

Study Design

Retrospective chart review.

Setting

Academic medical center.

Methods

We performed a review of 55 patients undergoing free flap reconstruction for OSCC over a 14-month period. Using texture analysis software, we measured the relative free flap fat volume (FFFV) in postoperative computed tomography scans and compared fat volume with patient survival, recurrence, and wound healing complications.

Results

We report no difference in mean FFFV between patients with or without recurrence: 13.47 cm³ in cancer-free survivors and 17.99 cm³ in cases that recurred (p = .56). Two-year recurrence-free survival in patients with high and low FFFV was 61.0% and 59.1%, respectively (p = .917). Although only 9 patients had wound healing complications, we found no trend in the incidence of wound healing complications between patients with high versus low FFFV.

Conclusion

FFFV is not associated with recurrence or wound healing in patients undergoing free flap reconstruction for OSCC, suggesting adipose content should not be of concern to the reconstructive surgeon.

Roles of mesenchymal stromal cells in the head and neck cancer microenvironment

Head and neck cancer (HNC), a common malignancy worldwide, is associated with high morbidity and mortality rates. Squamous cell carcinoma is the most common HNC type, followed by salivary gland carcinomas, head and neck sarcomas, and lymphomas. The microenvironment of HNCs comprises various cells that regulate tumor development. Recent studies have reported that the tumor microenvironment, which modulates cancer progression, regulates cancer treatment response. However, the presence of different types of stromal cells in cancers is a major challenge to elucidate the role of individual cells in tumor progression. The role of mesenchymal stromal cells (MSCs), which are a component of the tumor microenvironment, in HNC is unclear. The major impediment for characterizing the role of MSCs in cancer progression is the lack of MSC-specific markers and their phenotypic similarity with stromal cells. This review aimed to summarize the latest findings on the role of MSCs in the progression of HNC to improve our understanding of HNC pathophysiology.

Current approaches to management of vocal fold scar

PURPOSE OF REVIEW

Vocal fold (VF) fibrosis remains an insoluble problem in most cases, with a severe impact on vocal quality and effort. This review examines current investigations and research strands that explore the understanding of VF wound healing and applied treatments for the management of VF scar.

RECENT FINDINGS

Recent work focused on VF fibrosis has examined wound healing in the glottis, fibrosis-modifying medication, and tissue engineering approaches that span cytokine and growth factor therapy, scaffold and cell delivery platforms, seeded scaffolds, conditioned media and stem cell therapy. Many show promise and may deliver improvements in the wound bed favouring less fibrogenic healing patterns, ultimately with the goal of preserving or restoring VF vibration. Further collaborative research is required that examines combined approaches, long term outcomes, better three-dimensional modelling of cell-cell interactions and delivery modalities for molecular therapies.

SUMMARY

VF fibrosis research continues to expand and explore a variety of mechanistic pathways in order to understand VF healing and identify novel and complementary targets for manipulation. Many different approaches show promise and may also offer synergistic benefits. Research continues to strive for healing that more closely resembles true VF architecture and function.

Human Adipose-Derived Stem/Stromal Cells Promote Proliferation and Migration in Head and Neck Cancer Cells

Simple Summary

Fat grafts obtained from a minimal invasive liposuction device contain multipotent stem cells termed adipose-derived stem/stromal cells (ASCs). ASCs can be used for their proposed wound healing relevant characteristics, including for tissue defects in cancer patients. For head and neck cancers, little is known about the effects of ASCs on tumor cells. Using supernatants of ASCs from five patients in different functional experiments, this study aimed to investigate how ASCs influence tumor growth, invasive properties, and neoangiogenesis. The data show that all mentioned characteristics are promoted by fat graft stem cells in vitro in head and neck cancer cell lines. Although clinical relevance of these in vitro findings is unclear, due to the lack of in vivo and clinical data, fat grafts should be used cautiously and complete removal of tumor should be ensured before augmentation in head and neck cancer patients is performed.

Abstract

Human adipose-derived stem/stromal cells (ASCs) are increasingly used as auto-transplants in regenerative medicine to restore tissue defects or induce wound healing, especially in cancer patients. The impact of ASCs on squamous cell carcinoma of the upper aerodigestive tract (UAT) including head and neck and esophageal squamous cell carcinoma (HNSCC and ESCC) is not yet fully understood. ASCs were cultured from subcutaneous, abdominal lipoaspirates of five patients, who received auto-transplants to the head and neck. Supernatants were tested for paracrine effects in functional in vitro assays of proliferation of HNSCC tumor cell line FaDu and ESCC cell line Kyse30, and their cell migration/invasion capacities in Boyden chambers, in addition to endothelial tube formation assay using human umbilical vein endothelial cells (HUVECs). All ASC-derived supernatants enhanced proliferation of FaDu cells, invasive migration, and tube formation by HUVECs, compared to controls. Of five patients’ lipoaspirates, ASC-derived supernatants of four patients increased proliferation and invasive migration in Kyse30 cells. The data suggests that ASCs can promote tumor cell proliferation, invasiveness, and neo-angiogenesis in these tumor cell lines of the UAT and HUVEC in a paracrine manner. Although clinical studies on the subject of oncological safety are still needed, these findings emphasize the importance of complete tumor removal before ASCs are used in the head and neck.