Charlotte Lequeux

Improvement of skin quality after fat grafting: clinical observation and an animal study.

Background: Restoration of volume and contour defects is a challenge in plastic surgery. Autologous fat tissue transfer is gaining increasing popularity in this field. The aim of this study was to investigate the histologic modifications of the skin after fat tissue grafting on an animal model. Methods: Thirty nude mice, divided into three groups, were used in the experiment. All 30 mice received human fat tissue on one side. On the opposite side, 10 mice received nothing (negative control group), 10 mice received cell proliferation medium, and the remaining 10 mice received only subcutaneous tunneling. Eight weeks later, biopsies of the skin and subcutaneous tissue were performed and specimens were analyzed by hematoxylin-phloxin-saffron staining. Dermis thickness was measured. To differentiate human from murine collagen fibers, human and murine collagen type I antibodies were used. The other types of collagen were investigated by immunohistochemistry (immunostaining) using collagen type III, V, and VI antibodies. Results: Fat tissue was found in all animals. Macroscopically, fat tissue presented normal aspects, with abundant peripheral neovascularization. Histologic examination showed abundant extracellular matrix around the injected human fat tissue. This was attributable to increased type I collagen fibers of murine origin as a result of the murine fibroblast stimulation by the grafted human fat tissue. Dermal thickness after fat grafting was significantly greater. This was not attributable to inflammatory reactions, because no modification was detected in our control groups. Conclusions: This study shows that fat tissue grafting stimulates a neosynthesis of collagen fibers at the recipient site and makes the dermis thicker. However, the long-term effects remain undetermined and need further investigation.

Evolution of three dimensional skin equivalent models reconstructed in vitro by tissue engineering

Since the culture of keratinocytes on feeder layers, research to produce skin equivalents has been motivated by the challenge of treating large burns and chronic wounds and by European regulations which both require proof of the innocuousness and the effectiveness of cosmetic products, and which forbid animal testing. The dynamism in fundamental research, dermocosmetology and the pharmaceutical industry has led to the evolution and complexification of reconstructed skin. The Collagen-GAG-Chitosan sponge, as well as the self-assembly model, allow dermal reconstruction in which the neosynthesized extracellular matrix contains all of the desired macromolecules. It is deposited forming an ultrastructurally organised architecture. The quality of the dermis obtained allows the development and regeneration of a pluristratified and differentiated epidermis firmly anchored by an organised dermal-epidermal junction. Evolution of reconstructed skin into models which are more and more similar to the physiological skin results in higher graft take rates in the treatment of burns and chronic wounds, and brings to research, to dermocosmetology and to the pharmaceutical industry, a wide range of products such as pigmented, endothelialized, immunocompetent, and now adipose reconstructed skins. The present review will mainly concentrate on the latest developments in skin engineering and will mostly concern the studies carried out by our groups.

Reciprocal Interactions between Breast Tumor and Its Adipose Microenvironment Based on a 3D Adipose Equivalent Model

Breast cancer has become the most common cancer among women in industrialized countries. Obesity is well established as a risk factor, in particular owing to the attendant secretion of the entities called adipokines; there is growing evidence for a role of cells and factors present in the mammary tumor microenvironment such as fibroblasts, preadipocytes, adipocytes and their secretions. To study how the microenvironment influences breast cancer growth, we developed a novel tridimensional adipose model epithelialized with normal human keratinocytes or with breast cancer cell lines. These mimicked a breast tumor in contact with an adipose microenvironment and allowed monitoring of the interactions between the cells. Leptin and adiponectin, two major adipokines, and their respective receptors, ObRt and AdipoR1, were expressed in the model, but not the second adiponectin receptor, AdipoR2. The differentiation of preadipocytes into adipocytes was greater when they were in contact with the breast cancer cell lines. The contact of breast cancer cell lines with the microenvironment completely modified their transcriptional programs by increasing the expression of genes involved in cell proliferation (cyclinD1, MAPK), angiogenesis (MMP9, VEGF) and hormonal pathways (ESR1, IL6). This tridimensional adipose model provides new insights into the interactions between breast cancer cells and their adipose microenvironment, and provides a tool to develop new drugs for the treatment of both cancer and obesity.

Supernatants of Adipocytes From Obese Versus Normal Weight Women and Breast Cancer Cells: In Vitro Impact on Angiogenesis.

Breast cancer is correlated with a higher risk of metastasis in obese postmenopausal women. Adipokines, whose plasma concentrations are modulated in obese subjects and adipocytes surround mammary cells, suggesting that adipocyte secretome affect mammary tumorogenesis. We hypothesize that mature adipocyte secretions from obese women conditioned or not by breast neoplasic cells, increase changes on the angiogenesis stages. Supernatants of human mature adipocytes, differentiated from stem cells of either adipose tissue of normal weight (MA20) or obese (MA30) women or obtained from co‐cultures between MA20 and MA30 and breast cancer cell line MCF‐7, were collected. The impact of these supernatants was investigated on proliferation, migration, and tube formation by endothelial cells (HUVEC). MA20 and MA30 showed a preservation of their “metabolic memory” (increase of Leptin, ObR, VEGF, CYP19A1, and a decrease of Adiponectin expression in MA30 compared to MA20). Supernatants from obese‐adipocytes increased HUVEC proliferation, migration, and sprouting like with supernatants obtained from co‐cultures of MA/MCF‐7 regardless the womens BMI. Additional analyses such as the use of neutralizing antibodies, analysis of supernatants (Milliplex®) and variations in gene expression (qRT‐PCR), strongly suggest an implication of IL‐6, or a synergistic action among adipokines, probably associated with that of VEGF or IL‐6. As a conclusion, supernatants from co‐cultures of MA30 and MCF‐7 cells increase proliferation, migration, and sprouting of HUVEC cells. These results provide insights into the interaction between adipocytes and epithelial cancer cells, particularly in case of obesity. The identification of synergistic action of adipokines would therefore be a great interest in developing preventive strategies. J. Cell. Physiol. 232: 1808–1816, 2017.