Fat grafting and stem cell enhanced fat grafting to the breast under oncological aspects--recommendations for patient selection

Injectable Pectin-Alginate Hydrogels for Improving Vascularization and Adipogenesis of Human Fat Graft

Autologous fat grafting (AFG) is the most prevailing tool for soft tissue regeneration in clinics, although efficiency is limited to unpredictable volume resorption due to poor vascularization and eventual necrosis. This study sought to improve the AFG efficiency using a hydrogel as a carrier for human fat graft (F) with and without platelet-rich plasma (PRP). PRP is clinically well known for the local release of several endogenous growth factors and has been in clinical use already. A human-fat-graft-encapsulated pectin-alginate hydrogel (FG) was developed and characterized. PRP was added to F to develop a human fat graft with PRP (FP). FP was admixed with a pectin-alginate hydrogel to develop FGP. FG and FGP showed the smooth injectable, elastic, and shear-thinning properties. FG and FGP groups showed enhanced cell viability and proliferation compared to the control F in vitro. We also investigated the in vivo angiogenesis and neo-adipogenesis ability of F, FG, FGP, and FP in nude mice after subcutaneous injection. After 2 and 4 weeks, an MRI of the mice was conducted, followed by graft explantation. The explanted grafts were also assessed histologically and with immunohistochemistry (IHC) studies. MRI and histology results revealed better vascularity of the FG and FGP system compared to fat graft alone. Further, the IHC studies, CD 31, and perilipin staining also revealed better vasculature and adipogenesis of FG and FGP systems. These results indicate the enhanced angiogenesis and adipogenesis of FG and FGP. Thus, developed pectin-alginate hydrogel-based fat graft systems FG and FGP replenish the native microenvironment by mediating angiogenesis and adipogenesis, thereby maximizing the clinical outcomes of autologous fat grafting.

Interaction of adipose-derived stem cells with active and dormant breast cancer cells

BACKGROUND

Although autologous fat grafting is considered a successful method for the management of contour deformities, the fat graft could potentially induce cancer reappearance by fueling dormant breast cancer cells. Our aim was to characterize the role of adipose-derived stem cells on active and dormant breast cancer cell growth.

METHODS

Cobalt chloride was used to induce dormancy in MCF-7 cancer cells. Proliferation of active and dormant cancer cells was determined in the presence of adipose-derived stem cells. A proteome array was used to detect cancer-related protein expression in the cell-conditioned medium. The migration of cancer cells was measured in response to conditioned medium from the adipose-derived stem cells.

RESULTS

The adipose-derived stem cells showed variable effects on active MCF-7 cells growth and inhibited MCF-7 proliferation after the withdrawal of cobalt chloride. Of the 84 different proteins measured in the conditioned medium, only tenascin-C was differentially expressed in the co-cultures. MCF-7 cells alone did not express tenascin-C, whereas co-cultures between MCF-7 and adipose-derived stem cells expressed more tenascin-C versus adipose-derived stem cells alone. The conditioned medium from co-cultures significantly increased the migration of the cancer cells.

CONCLUSIONS

Adipose-derived stem cells themselves neither increased the growth or migration of cancer cells, suggesting that autologous fat grafting may be oncologically safe if reconstruction is postponed until there is no evidence of active disease. However, interactions between adipose-derived stem cells and MCF-7 cancer cells could potentially lead to the production of factors, which further promote cancer cell migration.

SINGLE-CENTER ONCOLOGIC OUTCOME OF FAT TRANSFER FOR BREAST RECONSTRUCTION FOLLOWING MASTECTOMY IN 1000 CANCER CASES - A MATCHED CASE-CONTROL STUDY

BACKGROUND

Autologous fat transfer (AFT) has an important role in breast reconstructive surgery. Nevertheless, Some concerns remain with regards to its oncological safety. We present a single center case-matching study analysing the impact of AFT in cumulative incidence of local recurrences (LR).

MATERIALS AND METHODS

From a prospectively maintained database, we identified 902 patients who underwent 1025 breast reconstructions from 2005 to 2017. Data regarding demographics, tumor characteristics, surgery details and follow-up were collected. Exclusion criteria were patients with distant metastases at diagnosis, recurrent tumor or incomplete data regarding primary tumor, patients who underwent prophylactic mastectomies and breast-conserving surgeries. Statistical analysis was done to evaluate the impact of the variables on the incidence of LR. A p-value < 0.05 was considered statistically significant.

RESULTS

After 1:n case-matching, we selected 919 breasts, out of which 425 (46.2%) patients received at least one AFT session vs 494 (53.8%) control cases. LR had an overall rate of 6.8% and we found LR in 14 (3.0%) AFT cases and 54 (9.6%) controls. Statistical analysis showed that AFT did not increase risk of LR: HR 0.337 (CI 0.173-0.658), p=0.00007. Multivariate analysis identified IDC subtype and lymph node metastases to have an increased risk of local recurrences (HR > 1). Conversely, positive hormonal receptor status was associated with a reduced risk of events (HR < 1).

CONCLUSIONS

AFT was not associated with a higher probability of locoregional recurrence in patients undergoing breast reconstruction therefore it can be safely used for total breast reconstruction or aesthetic refinements.LEVEL OF EVIDENCE: 3.

Banking of AT-MSC and its Influence on Their Application to Clinical Procedures

Processing of MSCs to obtain a therapeutic product consists of two main steps: 1) the in vitro expansion of the cells until an appropriate number of them is obtained, and 2) freezing and storage of the expanded cells. The last step is critical and must be optimized so that after thawing the cells retain all their physiological properties including the secretory function. In this paper, we evaluated physiological parameters of AT-MSC's after a full cycle of their processing, particularly freezing and storing at the liquid nitrogen vapor temperature. Based on the recovered proliferative and secretory capacities of the thawed cells, we have designed the optimal technique for processing of MSCs for clinical applications. In our work, we tried to select the best DMSO-based cryoprotectant mixture on the base of post thawing fully retain their properties. We have demonstrated the effectiveness of the use of DMSO in various configurations of the constituent cryoprotective fluids. We have also shown that AT-MSCs that show control levels in most standard tests (viability, shape, culture behaviour, and proliferative properties) after thawing, may show transient variations in some important physiological properties, such as the level of secreted growth factors. Obtained results let us to indicate how to optimize the AT-MSC preparation process for clinical applications. We suggest that before their clinical application the cells should be cultured for at least one passage to recover their physiological stability and thus assure their optimal therapeutic potential.

Interactions of BRCA1-mutated Breast Cancer Cell Lines with Adipose-derived Stromal Cells (ADSCs)

Lipofilling may constitute a technique to assist reconstruction of breasts following prophylactic mastectomy for patients with mutated BRCA1 or BRCA2 genes. However, to date it is not clear whether adipose-derived stromal cells (ADSCs) increase the risk of tumor initiation and progression in this situation. Therefore, the interactions of BRCA1 mutated breast cancer cell lines with normal ADSCs were investigated in the present study. Characteristics of MDA-MB-436 (BRCA1 c.5277 + 1G > A) and HCC1937 (BRCA1 p.Gln1756.Profs*74) were compared to MDA-MB-231 and T47D BRCA1/2 wild-type breast cancer cell lines. ADSCs were cultivated from lipoaspirates of a panel of BRCA1/2- wildtype patients. Interactions of conditioned medium (CM) of these cells with the breast cancer lines were studied using proliferation and migration assays as well as adipokine expression western blot arrays. CM of ADSCs exhibit a dose-dependent stimulation of the proliferation of the breast cancer cell lines. However, of the ADSC preparations tested, only 1 out of 18 samples showed a significant higher stimulation of BRCA1-mutated MDA-MB-436 versus wildtype MDA-MB-231 cells, and all CM revealed lower stimulatory activity for BRCA1-mutated HCC1937 versus wildtype T47D cells. Additionally, migration of breast cancer cells in response to CM of ADSCs proved to be equivalent or slower for BRCA1/2 mutated versus nonmutated cancer cells and, with exception of angiopoietin-like 2, induced expression of adipokines showed no major difference. Effects of media conditioned by normal ADSCs showed largely comparable effects on BRCA1-mutated and wildtype breast cancer cell lines thus advocating lipofilling, preferentially employing allogeneic non-mutated ADSCs.

Does Water-Jet Force Affect Cryopreserved Adipose-Derived Stem Cells? Evidence of Improved Cell Viability and Fat Graft Survival

BACKGROUND

Adipose tissue harvested by liposuctions is an available source of adipose-derived stem cells (ASCs). Water-jet-assisted liposuction is a favorable method for fat collection with little mechanical damage. This study aimed to investigate whether or not the water-jet-assisted liposuction made a difference in the biological characteristics of cryopreserved ASCs and fat graft survival in cell-assisted lipotransfer.

METHODS

Human lipoaspirates were obtained from the abdomen or thighs of 20 female participants for body contouring. A single surgeon randomly harvested 50 mL of adipose tissue by the water-jet-assisted liposuction and the conventional liposuction, respectively. Adipose-derived stem cells were isolated from lipoaspirates and then cryopreserved for 4 weeks. Cryopreserved ASCs were used to examine the surface markers, cell proliferation, migration, and adipogenic differentiation in vitro. The fat survival of ASCs-enriched grafts from different liposuctions was measured in animal models.

RESULTS

The cryopreserved ASCs with the water-jet assistance had better capacities of cell proliferation, migration, and adipogenic differentiation and achieved a better survival result of ASCs-enriched fat grafting.

CONCLUSIONS

Cryopreservation of ASCs with the water-jet force showed more excellent biological characteristics. The water-jet-assisted liposuction was superior to the conventional liposuction in obtaining ASCs and fat survival of coimplantation with grafts.

The Effects of Vasonatrin Peptide on Fat Graft Viability: An Experimental Study

Vasonatrin peptide (VNP) is a synthetic peptide that possesses vasodilatory, natriuretic, and anti-inflammatory properties. The authors aimed to analyze the effects of VNP on fat graft survival. Twenty Sprague-Dawley rats are randomly divided into two groups of 10. Fat grafts are harvested from the right inguinal region. After preparation, fat grafts are placed to the interscapular region. The first group of rats were administered VNP after their fat injection, while the second group received tail-vein injections of an equal volume of sterile saline following their fat injection. Experiment and control groups are evaluated according to their level of degeneration of adipocytes, fat necrosis, vacuolization, cyst formation in adipocytes, fibrosis of the fat tissue, capillary density, and CD31 immunohistochemical staining. Degeneration, vacuolization, and cyst formation in adipocytes were lower in the experiment group. Increased capillary density in the experiment group was demonstrated by CD31 antibody staining and by counting capillary density under a microscope. The average percentage of change in weight of the fat grafts in the experiment group was lower than that in the control group. The results indicate that VNP has some beneficial effects on fat graft survival by multiple independent mechanisms that influence both local and systemic homeostasis.

Phenotypic and Cellular Characteristics of a Stromal Vascular Fraction/Extracellular Matrix Gel Prepared Using Mechanical Shear Force on Human Fat

The retention of fat-derived grafts remains a challenge for regenerative medicine. Fat aspirates from patients undergoing liposuction were prepared into standard Coleman fat grafts or further isolated using mechanical shear force to prepare a stromal vascular fraction (SVF)/extracellular matrix (ECM) gel. The retention rate of the SVF/ECM gel was significantly higher than that of the Coleman fat at 3, 14, 28, and 60 days following transplantation on the backs of nude mice. The viscosity of the fat was directly proportional to the shearing force. Although the mechanical isolation did not affect the total number of cells, it significantly decreased the number of living cells. Flow cytometry showed a greater number of mesenchymal stem cells, supra-adventitial (SA)-adipose stromal cells (ASCs), and adipose-derived stem cells but a lower number of endothelial progenitor cells in the SVF/ECM gel than in the Coleman fat. Thus, mechanical isolation of fat can increase the pluripotency of adipocytes, which can improve graft retention in cell therapy.

Adipose tissue-derived mesenchymal stem cells for breast tissue regeneration

With an escalating incidence of breast cancer cases all over the world and the deleterious psychological impact that mastectomy has on patients along with several limitations of the currently applied modalities, it's plausible to seek unconventional approaches to encounter such a burgeoning issue. Breast tissue engineering may allow that chance via providing more personalized solutions which are able to regenerate, mimicking natural tissues also facing the witnessed limitations. This review is dedicated to explore the utilization of adipose tissue-derived mesenchymal stem cells for breast tissue regeneration among postmastectomy cases focusing on biomaterials and cellular aspects in terms of harvesting, isolation, differentiation and new tissue formation as well as scaffolds types, properties, material-host interaction and an in vitro breast tissue modeling.

Analysis of oncological safety of autologous fat grafting after immediate breast reconstruction

Background

Fat grafting is now a common procedure for breast reconstruction. Many clinical studies have reported its aesthetic efficacy and oncological safety, but some experimental studies raise about the recurrence risk because of its regenerating property. This study aims to investigate the possibility of cancer recurrence associated with fat grafting.

Methods

In this retrospective cohort study, we analyzed a total of 339 patients who had undergone immediate reconstructive surgery after nipple-sparing mastectomy (NSM) or skin-sparing mastectomy (SSM) in our institution between February 28, 2009 and March 23, 2019. Patients who had undergone breast conserving surgery, radical mastectomy, or delayed reconstruction were excluded. We used univariate and multivariate Cox proportional hazards regression models to evaluate the association between fat grafting and cancer recurrence.

Results

Among the 339 patients during a median follow-up of 52 months, 27 patients (8.0%) were confirmed to have recurrent cancer. Of 67 patients who had undergone fat grafting, 10 patients were confirmed to have cancer recurrence. In multivariate analyses, fat grafting [hazard ratio (HR), 2.52; 95% CI, 1.005-6.317; P=0.0488] was independently associated with cancer recurrence.

Conclusions

In population of breast cancer patient who underwent immediate reconstruction in our institution, fat grafting showed significant higher risk of cancer recurrence. Although these results are at odds with many existing studies, it suggests that more careful follow-up may be necessary for patients who had undergone fat grafting after reconstructive surgery.

Effects of Prophylactic Lipofilling After Radiotherapy Compared to Non-Fat Injected Breasts: A Randomized, Objective Study

BACKGROUND

Patients who are suffering from invasive breast cancer may require post-mastectomy radiation therapy (PMRT). PMRT improves outcomes in breast cancer patients in terms of locoregional recurrence. Preliminary studies indicate that fat injections reduce post-radiation damage of soft tissue and implants.

OBJECTIVES

The aim of this study was to demonstrate the safety and effectiveness of prophylactic fat injections on radiated implanted breasts.

METHODS

The authors randomly assigned 60 female patients to either Group A or B. Group A patients received 3 breast fat injections, according to Coleman's technique, after radiotherapy and before expander removal with definitive implant insertion. Group B patients underwent surgery without lipofilling. At each surgical operation, skin biopsies were performed in a specific breast area to evaluate adipose tissue thickness, and a statistical analysis of the thickness variations was performed with the Wilcoxon's sum test. Disability was assessed according to the Late Effects of Normal Tissues-Subjective Objective Management Analytic scale.

RESULTS

The study demonstrates a qualitative and quantitative improvement about tissues after fat injection. This is highlighted by the significant increase in thickness after lipofilling.

CONCLUSIONS

The study, which is based on both clinical and histological findings and is supported by the comparison of a control group with a 1-year follow-up, demonstrates that fat injections reduce tissue radio damage, improving reconstructive surgery outcomes and quality of life.

LEVEL OF EVIDENCE: 2

Tissue engineering applications in breast cancer

In Iran, breast cancer (BC) is the most prevalent cancer among women. The standard treatment for this cancer is partial or total removal of breast tissue, followed by chemotherapy and radiation. Tissue engineering (TE) has made new treatments for tissue loss in these patients by creating functional substitutes in the laboratory. In addition, cancer biology combined with TE provides a new strategy for evaluation of anti-BC therapy. Several innovations in TE have led to the design of scaffold or matrix based culture systems that more closely mimic the native extracellular matrix (ECM). Currently, engineered three-dimensional (3D) cultures are being developed for modelling of the tumour microenvironment. These 3D cultures fulfil the need for in vitro approaches that allow an accurate study of the molecular mechanisms and a better analysis of the drugs effect. In the present study, we review recent developments in utilising of TE in BC. Moreover, this review describes achievements of Iranian researchers in the field of breast TE.

Fat Therapeutics: The Clinical Capacity of Adipose-Derived Stem Cells and Exosomes for Human Disease and Tissue Regeneration

Fat grafting is a well-established surgical technique used in plastic surgery to restore deficient tissue, and more recently, for its putative regenerative properties. Despite more frequent use of fat grafting, however, a scientific understanding of the mechanisms underlying either survival or remedial benefits of grafted fat remain lacking. Clinical use of fat grafts for breast reconstruction in tissues damaged by radiotherapy first provided clues regarding the clinical potential of stem cells to drive tissue regeneration. Healthy fat introduced into irradiated tissues appeared to reverse radiation injury (fibrosis, scarring, contracture and pain) clinically; a phenomenon since validated in several animal studies. In the quest to explain and enhance these therapeutic effects, adipose-derived stem cells (ADSCs) were suggested as playing a key role and techniques to enrich ADSCs in fat, in turn, followed. Stem cells - the body's rapid response 'road repair crew' - are on standby to combat tissue insults. ADSCs may exert influences either by releasing paracrine-signalling factors alone or as cell-free extracellular vesicles (EVs, exosomes). Alternatively, ADSCs may augment vital immune/inflammatory processes; or themselves differentiate into mature adipose cells to provide the 'building-blocks' for engineered tissue. Regardless, adipose tissue constitutes an ideal source for mesenchymal stem cells for therapeutic application, due to ease of harvest and processing; and a relative abundance of adipose tissue in most patients. Here, we review the clinical applications of fat grafting, ADSC-enhanced fat graft, fat stem cell therapy; and the latest evolution of EVs and nanoparticles in healing, cancer and neurodegenerative and multiorgan disease.

MicroRNA-31 regulating apoptosis by mediating the phosphatidylinositol-3 kinase/protein kinase B signaling pathway in treatment of spinal cord injury

Apoptosis is a highly conservative energy demand program for non-inflammatory cell death, which is extremely significant in normal physiology and disease. There are many techniques used for studying apoptosis. MicroRNA (miRNA) is closely related to cell apoptosis, and especially microRNA-31 (miR-31) is involved in apoptosis by regulating a large number of target genes and signaling pathways. In many neurological diseases, cell apoptosis or programmed cell death plays an important role in the reduction of cell number, including the reduction of neurons in spinal cord injuries. In recent years, the phosphoinositol 3-kinase/AKT (PI3K/AKT) signal pathway, as a signal pathway involved in a variety of cell functions, has been studied in spinal cord injury diseases. The PI3K/AKT pathway directly or indirectly affects whether apoptosis occurs in a cell, thereby affecting a significant intracellular event sequence. This paper reviewed the interactions of miR-31 target sites in the PI3K/AKT signaling pathway, and explored new ways to prevent and treat spinal cord injury by regulating the effect of miR-31 on apoptosis.

European Survey Study Among Plastic/Breast Surgeons on the Use of and Opinion Toward Autologous Fat Transfer: With Emphasis on Breast Surgery

Objective. The aim of this study is to examine the experience of European surgeons on autologous fat transfer (AFT) and highlight differences between countries and levels of experience. Background Data. The popularity of AFT causes an increase in sophisticated scientific research and clinical implementation. While results from the former are well-documented, important aspects of the latter are far less recognized. Methods. An international survey study about surgeon background, besides AFT familiarity, technique, and opinion, was distributed among surgeons from 10 European countries. The differences between countries and levels of experience were analyzed using a logistic regression model. Results. The mean respondent age, out of the 358 completed questionnaires, was 46 years. Ninety-seven percent of the respondents were plastic surgeons, who practiced AFT mostly in breast surgery and considered themselves experienced with the technique. The thigh and abdomen were less favored harvest locations by the Belgium and French respondents, respectively, and both the French and Austrian respondents preferred manual aspiration over liposuction in harvesting the fat. Despite minor differences between countries and experience, the intraglandular space was injected in all subgroups. Conclusions. The expanding use of AFT in Europe will lead to more experience and heterogeneity regarding the technique. However, despite an obvious adherence to Coleman's method, deviations thereof become more apparent. An important example of such a deviation is the ongoing practice of intraglandular AFT despite being a contraindication in various European guidelines. These unsafe practices should be avoided until scientific clarification regarding oncological safety is obtained and should therefore be the focus of surgeon education in Europe.

Adipose-derived mesenchymal stem cells formed acinar-like structure when stimulated with breast epithelial cells in three-dimensional culture

Lipotransfer has been applied in breast augmentation surgery for several years and the resident adipose-derived stem cells (ASCs) play an important role in enhancing fat graft survival. However, the interaction between ASCs and mammary epithelium is not fully understood. Many studies have shown that ASCs have a tumor-supportive effect in breast cancer. To the best of our knowledge, this is the first study on the effect of mammary epithelial cells on the human ASCs in 3D culture. ASCs were cultivated on matrigel in the conditioned medium (CM) prepared from a human breast epithelial cell line (HBL-100). The ASCs formed KRT18-positive acini-like structures after stimulation with breast epithelial cells. The expression of epithelial genes (CDH1 and KRT18) was up-regulated while the expression of mesenchymal specific genes (CDH2 and VIM) was down-regulated as determined by qRT-PCR. The stemness marker (CD29) and angiogenic factors (CD31 and VEGF) were also down-regulated as examined by immunofluorescence. In addition, the CM obtained from HBL-100 enhanced the migration and inhibited the adipogenic differentiation of ASCs. These results demonstrate that ASCs have the ability to transform into epithelial-like cells when cultured with mammary epithelial cells. Given these observations, we infer that ASCs have a positive effect on lipotransfer, not only due to their ability to secrete growth factors, but also due to their direct participation in the formation of new breast tissue.

Adipose-derived stem cell-mediated paclitaxel delivery inhibits breast cancer growth

Breast cancer represents the main malignancy in women and autologous fat grafting is a diffuse procedure in the management of post-surgical breast defects causing patients’ psychosocial problems, with high costs for the public health. Recently, beneficial effects of fat grafting during post-surgical breast reconstruction have been amplified from the enrichment with human adipose-derived stem cells (ASCs) present in the stromal vascular fraction (SVF) of adult adipose tissue isolated during intraoperatory procedures. The major concern about the ASC enrichment during post-surgery breast reconstruction depends on their potential ability to release growth factors and hormones that can promote proliferation of residual or quiescent cancer cells, with the risk of de novo cancer development or recurrence. The recent description that adult stem cells primed in vitro may be vehicle for anti-cancer drug delivery offers a new vision concerning the role of ASCs in breast reconstruction after cancer surgery. Paclitaxel (PTX) is a chemotherapeutic agent acting as a microtubule-stabilizing drug inhibiting cancer cell mitotic activity. We optimized PTX loading and release in cultured ASCs and then analyzed the effects of PTX-loaded ASCs and their conditioned medium on CG5 breast cancer survival, proliferation and apoptosis in vitro, and inCG5 xenograft in vivo. We documented that ASCs can uptake and release PTX in vitro, with slight cytotoxic effects. Interestingly, PTX-loaded ASCs in co-culture, as well as conditioned medium alone, inhibited CG5 cell proliferation and survival in vitro and xenograft tumor growth in vivo. The antitumor effect of PTX-loaded ASCs may offer a new perspective concerning the use of ASCs during breast reconstruction becoming an additional local preventive chemotherapeutic agent against tumor recurrence. However, further experiments in vitro and in vivo are needed to collect more evidence confirming the efficacy and safety in cancer patients.

Revisiting the Advances in Isolation, Characterization and Secretome of Adipose-Derived Stromal/Stem Cells

Adipose-derived stromal/stem cells (ASCs) seems to be a promising regenerative therapeutic agent due to the minimally invasive approach of their harvest and multi-lineage differentiation potential. The harvested adipose tissues are further digested to extract stromal vascular fraction (SVF), which is cultured, and the anchorage-dependent cells are isolated in order to characterize their stemness, surface markers, and multi-differentiation potential. The differentiation potential of ASCs is directed through manipulating culture medium composition with an introduction of growth factors to obtain the desired cell type. ASCs have been widely studied for its regenerative therapeutic solution to neurologic, skin, wound, muscle, bone, and other disorders. These therapeutic outcomes of ASCs are achieved possibly via autocrine and paracrine effects of their secretome comprising of cytokines, extracellular proteins and RNAs. Therefore, secretome-derivatives might offer huge advantages over cells through their synthesis and storage for long-term use. When considering the therapeutic significance and future prospects of ASCs, this review summarizes the recent developments made in harvesting, isolation, and characterization. Furthermore, this article also provides a deeper insight into secretome of ASCs mediating regenerative efficacy.

Adipose-Derived Stem Cells in Novel Approaches to Breast Reconstruction: Their Suitability for Tissue Engineering and Oncological Safety

Adipose-derived stem cells (ADSCs) are rapidly becoming the gold standard cell source for tissue engineering strategies and hold great potential for novel breast reconstruction strategies. However, their use in patients with breast cancer is controversial and their oncological safety, particularly in relation to local disease recurrence, has been questioned. In vitro, in vivo, and clinical studies using ADSCs report conflicting data on their suitability for adipose tissue regeneration in patients with cancer. This review aims to provide an overview of the potential role for ADSCs in breast reconstruction and to examine the evidence relating to the oncologic safety of their use in patients with breast cancer.

Adipose-derived stem cells for breast reconstruction after breast surgery - preliminary results

Enrichment of fat grafts with adipose-derived stem cells (ASCs) has gained popularity due to promising preliminary results. Herein, we present two patients who were treated with ASC-enriched fat grafts following mastectomy and breast reconstruction with implants. Both exhibited favorable outcomes achieving a significant improvement of breast defects and asymmetries.

Potential Safety Loophole of Fat Grafting in Breast Cancer Patients

Autologous fat grafting (AFG) accounts for 9.1 % of all cosmetic surgical procedures in the world. Its use has been increasing tremendously in breast reconstruction and produces satisfying outcomes. However, the lack of standard guidelines for routine screening protocols in breast cancer patients before and after AFG warrants consideration of the safety of AFG use in post-mastectomy and post-lumpectomy reconstruction. This manuscript examines AFG in breast reconstruction publications and details the complications, the mechanism of AFG, as well as the relationship between adipose stem cells (ASCs) and cancer recurrence. The ASCs transferred in AFG act as multiple potent stem cells, which can impact cancer recurrence in various ways. Both in vitro and in vivo studies show that ASCs can stimulate the recurrence of breast cancer. Based on a review of existing evidence, we provide recommendations and guidelines for AFG use in breast reconstruction to aid in clinical decision-making. Further investigations are needed to evaluate the long-term clinical safety of AFG as well as the proposed guidelines.

NO LEVEL ASSIGNED

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.

Fat grafting for breast cancer patients: From basic science to clinical studies

Fat grafting in the surgical treatment of breast cancer has become popular in a short period of time because of the rising expectations of good esthetic results by the patients as well as the simplicity of the technique; however, the oncological safety for breast cancer patients remains a matter of debate. The procedure raises many questions considering that recent in-vitro studies have shown that fat grafting could promote tumor recurrence through diverse mechanisms, or even facilitate distant metastasis. We present a review of the currently available experimental and clinical data in order to describe and discuss patient selection criteria following breast cancer surgery.

Cell-Assisted Lipotransfer: A Systematic Review of Its Efficacy

INTRODUCTION

Autologous lipotransfer is seen as an ideal filler for soft tissue reconstruction. The main limitation of this procedure is the unpredictable resorption and volume loss of the fat graft. In the recent decade, an increasing amount of research has focused on the use of adipose tissue-derived stromal cells (ASCs) to enrich the fat graft, a procedure termed cell-assisted lipotransfer (CAL). The aim of this review was to systematically review the current preclinical and clinical evidence for the efficacy of CAL compared with conventional lipotransfer.

MATERIALS AND METHODS

A systematic search was performed on PubMed and other databases to identify all preclinical and clinical studies where CAL with ASCs was compared with conventional lipotransfer. A total of 20 preclinical studies and seven clinical studies were included in the review.

RESULTS

The preclinical studies consisted of 15 studies using immunodeficient animal models and five studies using immunocompetent studies. Seventeen studies examined weight/volume retention of which 15 studies favored CAL over conventional lipotransfer. One clinical study did not find any efficacy of CAL and the remaining six studies favored CAL.

CONCLUSIONS

The present evidence suggests that there is a big potential for CAL in reconstructive surgery; however, the present studies are so far still of low quality with inherent weaknesses. Several aspects regarding CAL still remain unknown such as the optimal degree of cell enrichment and also its safety. Further high-quality studies are needed to establish if CAL can live up to its potential.

LEVEL OF EVIDENCE V

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.

Imaging changes after breast reconstruction with fat grafting - Retrospective study of 90 breast cancer

Objective:

To evaluate the breast imaging changes after fat grafting and its impact on cancer follow up.

Methods:

This is a retrospective observational study conducted on patients who underwent fat grafting for breast reconstruction. We reviewed mammographic and ultrasound images of patients. Fisher’s exact test was used to analyze results. The level of significance was set at P < 0.05.

Results:

A total of ninety patients with breast cancer had fat grafting. Fifty eight patients for defects following post mastectomy reconstruction and 32 for wide local excision defects. The mean follow up was 37.4 months. Benign lumps were identified in 23/90 cases (25 percent). Mammograms were reported as BI-RADS I in 21/32 cases (72 percent) and BI-RADS II in 8/32 cases (28 percent). BI-RADs III score was reported in two patients on further follow up imaging, both were re-classified as BI-RADS II after biopsy. A total of eight patients (8.9 percent) required biopsy. No local recurrences or new cancers were observed in any patients.

Conclusion:

Our study suggests radiological changes after fat grafting are almost always benign with no adverse outcome on cancer follow up.

Interaction Between Breast Cancer Cells and Adipose Tissue Cells Derived from Fat Grafting

BACKGROUND

Adipose tissue transplantation has the benefit of providing both regenerative and aesthetic outcomes in breast cancer treatment. However, the transplanted tissue can stimulate the growth of residual cancer cells.

OBJECTIVES

The aim of this study is to identify the interactions between adipose tissue cell subpopulations and human cancer cell lines.

METHODS

Intact adipose tissue from lipofilling procedures as well as fibroblasts derived from adipose tissue, were cocultured in the presence of MDA-MB-231, MCF-7 e ZR-75-1 breast cancer cell lines. The influence on cancer cell lines of fibroblasts, induced to differentiate into specific adipocytes, was also assayed.

RESULTS

All cancer cell lines displayed a significant increase in proliferation rate when cocultured in the presence of either intact adipose tissue or induced adipocytes. To a lesser extent, uninduced fibroblasts stimulate breast cancer cell proliferation.

CONCLUSIONS

Recent studies have shown that the microenvironment surrounding breast cancer cells may stimulate growth and promote progression of residual cancer cells when surgery is performed on the main tumor mass. Accordingly, the graft of adipose tissue could potentially promote or accelerate the development of a subclinical tumor or support its locoregional recurrence. Our data suggest that adipocytes have a remarkable influence on the proliferation of cancer cell lines. The oncological safety of the lipofilling procedure outcome is still debated; thus, further studies and consistent follow-up examination are needed.

Adipose-Derived Stromal Vascular Fraction Differentially Expands Breast Progenitors in Tissue Adjacent to Tumors Compared to Healthy Breast Tissue

Supplemental Digital Content is available in the text.

Background:

Autologous fat grafts supplemented with adipose-derived stromal vascular fraction are used in reconstructive and cosmetic breast procedures. Stromal vascular fraction contains adipose-derived stem cells that are thought to encourage wound healing, tissue regeneration, and graft retention. Although use of stromal vascular fraction has provided exciting perspectives for aesthetic procedures, no studies have yet been conducted to determine whether its cells contribute to breast tissue regeneration. The authors examined the effect of these cells on the expansion of human breast epithelial progenitors.

Methods:

From patients undergoing reconstructive breast surgery following mastectomies, abdominal fat, matching tissue adjacent to breast tumors, and the contralateral non–tumor-containing breast tissue were obtained. Ex vivo co-cultures using breast epithelial cells and the stromal vascular fraction cells were used to study the expansion potential of breast progenitors. Breast reduction samples were collected as a source of healthy breast cells.

Results:

The authors observed that progenitors present in healthy breast tissue or contralateral non–tumor-containing breast tissue showed significant and robust expansion in the presence of stromal vascular fraction (5.2- and 4.8-fold, respectively). Whereas the healthy progenitors expanded up to 3-fold without the stromal vascular fraction cells, the expansion of tissue adjacent to breast tumor progenitors required the presence of stromal vascular fraction cells, leading to a 7-fold expansion, which was significantly higher than the expansion of healthy progenitors with stromal vascular fraction.

Conclusions:

The use of stromal vascular fraction might be more beneficial to reconstructive operations following mastectomies compared with cosmetic corrections of the healthy breast. Future studies are required to examine the potential risk factors associated with its use.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, V.

Strategic sequences in fat graft survival

Although lipotransfer, or fat grafting, is a commonly used procedure in aesthetic and reconstructive surgery, there is still variability in graft survival and neoadipogenesis from one procedure to the next. A better understanding of the sequential molecular events occurring with grafting would allow us to strategize methods to improve the regenerative potency of the grafted tissue. These steps begin with an autophagic process, followed by the inclusion of stromal vascular fraction and matrix components. By tailoring and modifying each of these steps for a particular type of aesthetic or reconstructive procedure, strategic sequencing represents a dynamic approach to lipotransfer with the aim of maximizing adipocyte viability and growth. In the implementation of the strategic sequence, it remains important to consider the clinical viability of each step and its compliance with the US Food and Drug Administration regulations. This review highlights the basic science behind clinically translatable approaches to supplementing various fat grafting procedures.

Human Adipose-Derived Mesenchymal Stromal Cells May Promote Breast Cancer Progression and Metastatic Spread

BACKGROUND

Stem cell-enriched fat grafting has been proposed as a potential therapy for reconstructive, restorative, or enhancement-related procedures of the breast. Its role in postoncologic breast reconstruction is still emerging, with concerns about safety. The authors investigated the dose-dependent interaction between human adipose-derived mesenchymal stromal cells (AD-MSCs) and human breast cancer cell (BCC) lines [MDA-MB-231 (MDA) and MCF-7 (MCF)] focusing on tumor microenvironment, tumor growth, and metastatic spread.

METHODS

Adipose-derived mesenchymal stromal cell influence on viability and factor expression [regulated on activation, normal T cell expressed and secreted (RANTES), tumor necrosis factor-α, and eotaxin) of breast cancer cells was studied in vitro using direct and indirect co-culture systems. Groups were formed according to adipose-derived mesenchymal stromal cell-to-cancer cell number ratio [MDA/MCF only, AD-MSC/(MDA/MCF), and AD-MSC/(MDA/MCF)]. A humanized orthotopic murine cancer model was used to evaluate breast cancer progression and metastasis (n = 10/group). Cells were injected into the mammary pad in different ratios and animals were monitored over 42 days. Microdialysis was performed to analyze RANTES levels in the tumor microenvironment (days 21 and 42). Primary and metastatic tumors were weighed and analyzed for oncogene, growth factor, and metastatic marker expression.

RESULTS

MDA cell viability increased from 45.5 percent to 95.5 percent in presence of adipose-derived mesenchymal stromal cells in vitro. In vivo, animals with AD-MSC showed increased mean tumor weight (MDA, p < 0.01; MCF versus controls, p < 0.05) and metastatic occurrence (40 percent in MDA; 30 percent in MCF versus 0 percent in controls). Cytokine analysis revealed switching of MCF tumor phenotype to a more malignant type in the presence of adipose-derived mesenchymal stromal cells.

CONCLUSION

Human adipose-derived mesenchymal stromal cells may promote progression and metastatic spread in breast cancer through a switch to a more malignant phenotype with worse prognosis.

Obesity, proinflammatory mediators, adipose tissue progenitors, and breast cancer

PURPOSE OF REVIEW

There is emerging evidence that obesity is associated with an increase in the incidence, severity, and mortality from different types of cancer, including postmenopausal breast cancer. Here, we discuss the role of white adipose tissue (WAT) cells and of related soluble factors in the local and metastatic growth of this neoplastic disease. Moreover, we discuss the recent increase in the use of WAT-derived progenitor cells in breast cancer patients to enhance the quality of breast reconstruction and the related risks.

RECENT FINDINGS

In several murine models, WAT cells and progenitors were found to have cooperative roles in promoting local breast cancer. Moreover, they were found to contribute to adipocytes and pericytes supporting the cancer vasculature, and stimulated the metastatic progression of breast cancer. There are some clinically retrospective data showing a significant increase in the frequency of intraepithelial neoplasia in patients who received a lipofilling procedure for breast reconstruction compared with controls.

SUMMARY

Preclinical models and clinical studies are urgently needed to investigate how to inhibit the tumor-promoting activity of WAT cells and progenitors. The risks associated with the use of WAT cells for breast reconstructions should be better investigated retrospectively and prospectively.

In vitro effects of tamoxifen on adipose-derived stem cells

In breast reconstructive procedures, adipose-derived stem cells (ASCs) that are present in clinical fat grafting isolates are considered to play the main role in improving wound healing. In patients following chemotherapy for breast cancer, poor soft tissue wound healing is a major problem. However, it is unclear if tamoxifen (TAM) as the most widely used hormonal therapeutic agent for breast cancer treatment, affects the ASCs and ultimately wound healing. This study evaluated whether TAM exposure to in vitro human ASCs modulate cellular functions. Human ASCs were isolated and treated with TAM at various concentrations. The effects of TAM on cell cycle, cell viability and proliferation rates of ASCs were examined by growth curves, MTT assay and BrdU incorporation, respectively. Annexin V and JC-1 Mitochondrial Membrane Potential assays were used to analyze ASC apoptosis rates. ASCs were cultured in derivative-specific differentiation media with or without TAM (5 uM) for 3 weeks. Adipogenic and osteogenic differentiation levels were measured by quantitative RT-PCR and histological staining. TAM has cytotoxic effects on human ASCs through apoptosis and inhibition of proliferation in dose- and time-dependent manners. TAM treatment significantly down-regulates the capacity of ASCs for adipogenic and osteogenic differentiation (p<0.05 vs. control), and inhibit the ability of the ASCs to subsequently formed cords in Matrigel. This study is the first findings to our knowledge that demonstrated that TAM inhibited ASC proliferation and multi-lineage ASC differentiation rates. These results may provide insight into the role of TAM with associated poor soft tissue wound healing and decreased fat graft survival in cancer patients receiving TAM.

The role of adipose-derived stem cells in breast cancer progression and metastasis

Conventional breast cancer extirpation involves resection of parts of or the whole gland, resulting in asymmetry and disfiguration. Given the unsatisfactory aesthetic outcomes, patients often desire postmastectomy reconstructive procedures. Autologous fat grafting has been proposed for reconstructive purposes for decades to restore form and anatomy after mastectomy. Fat has the inherent advantage of being autologous tissue and the most natural-appearing filler, but given its inconsistent engraftment and retention rates, it lacks reliability. Implementation of autologous fat grafts with cellular adjuncts, such as multipotent adipose-derived stem cells (ADSCs), has shown promising results. However, it is pertinent and critical to question whether these cells could promote any residual tumor cells to proliferate, differentiate, or metastasize or even induce de novo carcinogenesis. Thus far, preclinical and clinical study findings are discordant. A trend towards potential promotion of both breast cancer growth and invasion by ADSCs found in basic science studies was indeed not confirmed in clinical trials. Whether experimental findings eventually correlate with or will be predictive of clinical outcomes remains unclear. Herein, we aimed to concisely review current experimental findings on the interaction of mesenchymal stem cells and breast cancer, mainly focusing on ADSCs as a promising tool for regenerative medicine, and discuss the implications in clinical translation.

Adipose-derived stem cells in radiotherapy injury: a new frontier

Radiotherapy is increasingly used to treat numerous human malignancies. In addition to the beneficial anti-cancer effects, there are a series of undesirable effects on normal host tissues surrounding the target tumor. While the early effects of radiotherapy (desquamation, erythema, and hair loss) typically resolve, the chronic effects persist as unpredictable and often troublesome sequelae of cancer treatment, long after oncological treatment has been completed. Plastic surgeons are often called upon to treat the problems subsequently arising in irradiated tissues, such as recurrent infection, impaired healing, fibrosis, contracture, and/or lymphedema. Recently, it was anecdotally noted - then validated in more robust animal and human studies - that fat grafting can ameliorate some of these chronic tissue effects. Despite the widespread usage of fat grafting, the mechanism of its action remains poorly understood. This review provides an overview of the current understanding of: (i) mechanisms of chronic radiation injury and its clinical manifestations; (ii) biological properties of fat grafts and their key constituent, adipose-derived stem cells (ADSCs); and (iii) the role of ADSCs in radiotherapy-induced soft-tissue injury.

Stem cells from adipose tissue and breast cancer: hype, risks and hope

Several recent papers have generated new hope about the use of white adipose tissue (WAT)-derived progenitor cells for soft tissue reconstruction in a variety of diseases including breast cancer (BC), a procedure that is increasingly used worldwide. We revised the available literature about WAT cells and BC. In the BC field, we believe that the hype for the exciting results in terms of WAT progenitor cell engraftment and tissue augmentation should be tempered when considering the recent and abundant preclinical studies, indicating that WAT progenitors may promote BC growth and metastasis. White adipose tissue progenitors can contribute to tumour vessels, pericytes and adipocytes, and were found to stimulate local and metastatic BC progression in several murine models. Moreover, there are clinical retrospective data showing a significant increase in the local recurrence frequency in patients with intraepithelial neoplasia who received a lipofilling procedure for breast reconstruction compared with controls. Retrospective and prospective clinical trials are warranted to investigate in depth the safety of this procedure in BC. Preclinical models should be used to find mechanisms able to inhibit the tumour-promoting activity of WAT progenitors while sparing their tissue reconstruction potential.

Breast reconstruction de novo by water-jet assisted autologous fat grafting--a retrospective study

BACKGROUND

Autologous fat grafting has become a frequent, simple, reproducible and low-risk technique for revisional or partial breast reconstruction. The presented European multicenter study describes an optimized treatment and follow-up protocol for the de novo breast reconstruction after total mastectomy by lipotransfer alone.

METHODS

A retrospective European multicenter trial included 135 procedures on 28 (35 breasts) postmastectomy patients (mean 52.4 years). All women were treated with the water-jet assisted fat grafting method (BEAULI™) combined with additional procedures (NAC reconstruction, contralateral mastoplasty) and evaluated with at least 6 months follow-up (mean 2.6 years). Sonography or mammography, clinical examination, patient questionnaire (10-point Likert scale) and digital photographs were carried out.

RESULTS

On average the patients received 4 to 6 procedures each with a single volume of 159 ml (±61 ml) over 21 months (range 9 months to 2.5 years). In total 1,020 ml (±515 ml) fat were grafted till a complete breast reconstruction was achieved. Irradiated patients needed a significantly higher volume than non-irradiated (p<0.041). Main treatment complications were liponecrosis (2.59%), infection (0.74%) and granuloma (0.74%). Patient satisfaction was overall high to very high (96%) and confirmed the good aesthetic results (68%) and the natural softness, contour and shape of the reconstructed breast.

CONCLUSIONS

A complete breast reconstruction with large volume fat grafting is alternatively possible to standard techniques in selected cases. It takes at least 4 to 6 lipotransfers in the course of 2 years. Patients with prior radiotherapy may require even up to 8 sessions over nearly 3 years of treatment.