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Background: Assisted lipotransfer for breast reconstruction involves the isolation and supplementation of adipose-derived stromal cells. This procedure has raised concerns regarding safety with respect to promotion of tumor growth and relapse. Several in vitro and animal experimental studies have indicated increased survival, growth, and invasive characteristics of breast cancer cells on interaction with adipose-derived stromal cells. These results seem to be in poor concordance with clinical observations of a low rate of cancer recurrences after assisted lipotransfer. Methods: The authors investigated the effects of adipose-derived stromal cells and adipose-derived stromal cells differentiated into adipocytes and fibroblasts on five breast cancer cell lines (i.e., T47D, MCF-7, BT20, MDA-MB-231, and ZR-75-1) and MCF-10A, a nonmalignant counterpart. Results: Conditioned media of adipose-derived stromal cells stimulated the proliferation of breast cancer cell lines depending on the individual adipose-derived stromal cell–breast cancer cell line combination. Conditioned media of adipose-derived stromal cells differentiated into adipocytes gave a lower response, and conditioned media of fibroblasts were also active. A putative cancer stem cell–like phenotype was not increased by adipose-derived stromal cell–conditioned media, no physical interaction of cancer cells with adipose-derived stromal cells was detectable on scanning electron microscopy, and cell migration was not enhanced. Adipogenic differentiation of adipose-derived stromal cells indicated that hepatocyte growth factor, insulin-like growth factor-binding protein-3, insulin-like growth factor-binding protein-6, interleukin-6, CCL2/MCP-1, and macrophage colony-stimulating factor are not linked to the proliferative activity of conditioned media. Conclusion: The results indicate that the adipose-derived stromal cells used for assisted lipotransfer are not expected to increase the risk of tumor recurrence to a major degree in correspondence with the clinical observation of the affected breast cancer patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Metformin is used to treat patients with type 2 diabetes mellitus and was found to lower the incidence of cancer. Bone metastasis is a common impairment associated with advanced breast cancer. The present study investigated the effects of metformin on human bone-derived mesenchymal stromal cells (BM-MSC)—breast cancer cell line interactions. BM-MSCs grown from box chisels were tested for growth-stimulating and migration-controlling activity on four breast cancer cell lines either untreated or after pretreatment with metformin. Growth stimulation was tested in MTT tests and migration in scratch assays. Furthermore, the expression of adipokines of BM-MSCs in response to metformin was assessed using Western blot arrays. Compared to breast cancer cell lines (3.6 ± 1.4% reduction of proliferation), 500 µM metformin significantly inhibited the proliferation of BM-MSC lines (mean 12.3 ± 2.2 reduction). Pretreatment of BM-MSCs with metformin showed variable effects of the resulting conditioned media (CM) on breast cancer cell lines depending on the specific BM-MSC—cancer line combination. Metformin significantly reduced the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in response to CM of drug-pretreated BM-MSCs. Assessment of metformin-induced alterations in the expression of adipokines by BM-MSC CM indicated increased osteogenic signaling and possibly impairment of metastasis. In conclusion, the anticancer activities of metformin are the result of a range of direct and indirect mechanisms that lower tumor proliferation and progression. A lower metformin-induced protumor activity of BM-MSCs in the bone microenvironment seem to contribute to the positive effects of the drug in selected breast cancer patients.

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Depending on their extent, burn injuries require different treatment strategies. In cases of severe large-area trauma, the availability of vital skin for autografting is limited. Donor skin allografts are a well-established but rarely standardized option for temporary wound coverage. Ten patients were eligible for inclusion in this retrospective study. Overall, 202 donor skin grafts obtained from the in-house skin bank were applied in the Department of Plastic and Reconstructive and Aesthetic Surgery, Medical University of Vienna. Between 2017 and 2022, we analysed the results in patient treatment, the selection of skin donors, tissue procurement, tissue processing and storage of allografts, as well as the condition and morphology of the allografts before application. The average Abbreviated Burn Severity Index (ABSI) was 8.5 (range, 5–12), and the mean affected total body surface area (TBSA) was 46.1% (range, 20–80%). In total, allograft application was performed 14 times. In two cases, a total of eight allografts were removed due to local infection, accounting for 3.96% of skin grafts. Six patients survived the acute phase of treatment. Scanning electron microscope images and histology showed no signs of scaffold decomposition and intact tissue layers of the allografts. The skin banking program and the application of skin allografts at the Vienna Burn Center can be considered successful. In severe burn injuries, skin allografts provide time by serving as sufficient wound coverage after early necrosectomy. Having an in-house skin banking program at a dedicated burn centre is particularly advantageous since issues of availability and distribution can be minimized. Skin allografts provide a reliable treatment option in patients with extensive burn injuries.