Human Embryonic Stem Cell-Derived Endothelial Precursor Cell Conditioned Medium Reduces the Thickness of the Capsule Around Silicone Implants in Rats

Implantation and tracing of green fluorescent protein-expressing adipose-derived stem cells in peri-implant capsular fibrosis

BACKGROUND

Adipose-derived stem cells (ASCs) have been reported to reduce fibrosis in various tissues. In this study, we investigated the inhibitory role of ASCs on capsule formation by analyzing the histologic, cellular, and molecular changes in a mouse model of peri-implant fibrosis. We also investigated the fate and distribution of ASCs in the peri-implant capsule.

METHODS

To establish a peri-implant fibrosis model, customized silicone implants were inserted into the dorsal site of C57BL/6 wild-type mice. ASCs were harvested from the fat tissues of transgenic mice that express a green fluorescent protein (GFP-ASCs) and then injected into the peri-implant space of recipient mice. The peri-implant tissues were harvested from postoperative week 2 to 8. We measured the capsule thickness, distribution, and differentiation of GFP-ASCs, as well as the cellular and molecular changes in capsular tissue following ASC treatment.

RESULTS

Injected GFP-ASCs were distributed within the peri-implant capsule and proliferated. Administration of ASCs reduced the capsule thickness, decreased the number of myofibroblasts and macrophages in the capsule, and decreased the mRNA level of fibrogenic genes within the peri-implant tissue. Angiogenesis was enhanced due to trans-differentiation of ASCs into vascular endothelial cells, and tissue hypoxia was relieved upon ASC treatment.

CONCLUSIONS

We uncovered that implanted ASCs inhibit capsule formation around the implant by characterizing a series of biological alterations upon ASC treatment and the fate of injected ASCs. These findings highlight the value of ASCs for future clinical applications in the prevention of capsular contracture after implant-based reconstruction surgery.

Effectiveness of Topical Conditioned Medium of Stem Cells in Facial Skin Nonsurgical Resurfacing Modalities for Antiaging: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Facial skin nonsurgical resurfacing modalities, including laser, chemical peeling, and microneedling, have become common due to increasing public concern about skin aging. The potential effect of stem cell conditioned medium (CM) for antiaging has been reported in recent years, and such medium may be able to improve the efficacy of resurfacing modalities. This study investigated the efficacy of topical CM combined with resurfacing in comparison with resurfacing alone. We searched the PubMed, Embase, and Cochrane Library databases for randomized controlled trials (RCTs). We used the Cochrane risk-of-bias tool (version 2) to assess the risk of bias of the included studies and Review Manager (version 5.4) for data analysis. Means and standard deviations of outcomes, namely wrinkle, pigmentation, pore, and overall improvement, were extracted. After screening, we included five RCTs in the analysis, four of which were quantitatively analyzed. The result revealed that stem cell CM significantly reduced wrinkles (P = 0.0006), pigmentation (P = 0.004), and pores (P = 0.01) and improved overall skin condition (P < 0.0001). In summary, we suggest that stem cell CM is a safe treatment that can enhance the efficacy of facial skin nonsurgical resurfacing modalities.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 .

Molecular profiling reveals a hypoxia signature in breast implant-associated anaplastic large cell lymphoma

Breast implant-associated anaplastic large cell lymphoma (BIAALCL) is a recently characterized T-cell malignancy that has raised significant patient safety concerns and led to worldwide impact on the implants used and clinical management of patients undergoing reconstructive or cosmetic breast surgery. Molecular signatures distinguishing BIA-ALCL from other anaplastic large cell lymphomas have not been fully elucidated and classification of BIA-ALCL as a World Health Organization entity remains provisional. We performed RNA sequencing and gene set enrichment analysis comparing BIA-ALCL to non-BIAALCL and identified dramatic upregulation of hypoxia signaling genes including the hypoxia-associated biomarker CA9 (carbonic anyhydrase- 9). Immunohistochemistry validated CA9 expression in all BIA-ALCL, with only minimal expression in non-BIA-ALCL. Growth induction in BIA-ALCL-derived cell lines cultured under hypoxic conditions was proportional to upregulation of CA9 expression, and RNA sequencing demonstrated induction of the same gene signature observed in BIAALCL tissue samples compared to non-BIA-ALCL. CA9 silencing blocked hypoxia-induced BIA-ALCL cell growth and cell cycle-associated gene expression, whereas CA9 overexpression in BIA-ALCL cells promoted growth in a xenograft mouse model. Furthermore, CA9 was secreted into BIA-ALCL cell line supernatants and was markedly elevated in human BIA-ALCL seroma samples. Finally, serum CA9 concentrations in mice bearing BIA-ALCL xenografts were significantly elevated compared to those in control serum. Together, these findings characterize BIA-ALCL as a hypoxia-associated neoplasm, likely attributable to the unique microenvironment in which it arises. These data support classification of BIA-ALCL as a distinct entity and uncover opportunities for investigating hypoxia-related proteins such as CA9 as novel biomarkers and therapeutic targets in this disease.