Relationship between Tamoxifen and the Absorption of Subfascial Autologous Fat Grafts

Influence of Tamoxifen on Different Biological Pathways in Tumorigenesis and Transformation in Adipose-Derived Stem Cells, Mammary Cells and Mammary Carcinoma Cell Lines—An In Vitro Study

Breast carcinoma is one of the most common malignant tumors in women. In cases of hormone-sensitive cells, tamoxifen as an anti-estrogenic substance is a first line medication in the adjuvant setting. The spectrum of autologous breast reconstructions ranges from fat infiltrations to complex microsurgical procedures. The influence of adipose-derived stem cells (ASC) on the tumor bed and a possibly increased recurrence rate as a result are critically discussed. In addition, there is currently no conclusive recommendation regarding tamoxifen-treated patients and autologous fat infiltrations. The aim of the present study was to investigate the effect of tamoxifen on the gene expression of a variety of genes involved in tumorigenesis, cell growth and transformation. Mammary epithelial cell line and mammary carcinoma cell lines were treated with tamoxifen in vitro as well as co-cultured with ASC. Gene expression was quantified by PCR arrays and showed increased expression in the mammary carcinoma cell lines with increasing time of treatment and concentration of tamoxifen. The data presented can be considered as an addition to the controversial discussion on the relationship between ASC and breast carcinoma cells. Further studies are needed to quantify the in vivo interaction of ASC and mammary carcinoma cells and to conclusively assess the impact of tamoxifen in reconstructive cases with fat grafting.

Assessment of facial autologous fat grafts using Dixon magnetic resonance imaging

BACKGROUND

Autologous fat grafting is a procedure that treats soft tissue defects by reallocating fat to improve a patient's physical appearance. Imaging methods may be used to evaluate and monitor the grafted fat after transplantation. The goal of imaging is to examine the signal and volume of the grafted fat after autologous fat grafting during the adipose tissue recovery. However, researchers have yet to examine the feasibility of using fat-only imaging to assess the autologous fat graft.

METHODS

In this prospective and observational study, 46 injected sides in 23 female patients (age 35±7.8 years) were included in the image evaluation. The patients underwent autologous fat grafting surgery with filtered and washed fat. A total of 16, 18, and 12 sides were scanned 7 days, 3 months, and 1 year after fat grafting, respectively. Fat-only images were obtained using Dixon imaging, and then the image quality and contrast of the T1W and T2W were rated to evaluate the application of this method when imaging the autologous fat. The signal and volume of the autologous fat graft were recorded to assess the retention during recovery of the autologous fat tissue.

RESULTS

Fat-only T1W magnetic resonance imaging (MRI) was used to identify and delineate grafted fat because this method had better image quality and image differentiation than did T2W MRI. The average signal contrast and retention rate measured 7 days postoperation (28.8%±4.7%; 94.1%±5.8%) was the highest and then decreased at 3 months (16.3%±2.1%; 48.7%±17.3%) and 1 year (3.3%±1.3%, 33.1%±12.9%) after surgery. There were statistically significant differences between the signal and volume retention measurements at each postoperative recovery phase.

CONCLUSIONS

The T1W fat-only images produced by Dixon MRI is a feasible approach for identifying grafted fat and measure postoperative changes during clinical evaluation. We found a significant decrease in signal contrast and volume of the grafted fat from the surgery date to 3 months postoperation and from 3 months to 1-year postoperation.

UK Guidelines for Lipomodelling of the Breast on behalf of Plastic, Reconstructive and Aesthetic Surgery and Association of Breast Surgery Expert Advisory Group

Lipomodelling has become increasingly popular for reconstructive, aesthetic and therapeutic indications. The guidelines summarise available evidence for indications, training, technique, audit and outcomes in lipomodelling and also highlight areas for further research.

miR-26b-5p/TCF-4 Controls the Adipogenic Differentiation of Human Adipose-derived Mesenchymal Stem Cells

In this study, we assessed the ability of miR-26b-5p to regulate T cell factor 4 (TCF-4) expression and thereby control human adipose-derived mesenchymal stem cell (hADMSC) adipogenic differentiation. Adipogenic medium was used to induce hADMSC differentiation over a 6-d period. The ability of miR-26b-5p to interact with the TCF-4 mRNA was confirmed through both predictive bioinformatics analyses and luciferase reporter assays. Immunofluorescent staining was used to visualize the impact of miR-26b-5p inhibition or overexpression on TCF-4 and β-catenin levels in hADMSCs. Further functional analyses were conducted by transfecting these cells with siRNAs specific for TCF-4 and β-catenin. Adipogenic marker and Wnt/β-catenin pathway gene expression levels were assessed via real-time polymerase chain reaction and western blotting. β-catenin localization was assessed via immunofluorescent staining. As expected, our adipogenic media induced the adipocytic differentiation of hADMSCs. In addition, we confirmed that TCF-4 is an miR-26b-5p target gene in these cells, and that protein levels of both TCF-4 and β-catenin were reduced when these cells were transfected with miR-26b-5p mimics. Overexpression of this microRNA also enhanced hADMSC adipogenesis, whereas TCF-4 and β-catenin overexpression inhibited this process. The enhanced hADMSC adipogenic differentiation that was observed following TCF-4 or β-catenin knockdown was partially reversed when miR-26b-5p expression was inhibited. We found that miR-26b-5p serves as a direct negative regulator of TCF-4 expression within hADMSCs, leading to inactivation of the Wnt/β-catenin pathway and thereby promoting the adipogenic differentiation of these cells in vitro.

Evaluation of the ex vivo Effects of Tamoxifen on Adipose-Derived Stem Cells: A Pilot Study

Autologous fat grafting (AFG) is a safe and minimally invasive procedure to correct soft tissue defects. The benefit of AFG is attributed to adipose-derived stem cells (ASCs) in fat tissue graft. This technique is useful also in patients undergoing reconstructive surgery following quadrantectomy for breast cancer. However, these patients are frequently treated with tamoxifen. We evaluated the ex vivo effects of tamoxifen on ASCs to understand if cellular functions of ASCs are affected. We selected 24 female patients; 10 of which were breast cancer patients treated with quadrantectomy and tamoxifen. As control group, we selected 14 healthy female subjects (9 premenopausal and 5 menopausal). We found that tamoxifen has no effect on cellular proliferation, VEGF secretion or apoptosis of ASCs. The gene expression assessment demonstrated no impairment in differentiation capacity of ASCs. Our results showed that tamoxifen has no effect on cellular functions of ASCs for the first time in an ex vivo single-center study.