No abstract

Repair of soft-tissue defects resulting from lumpectomy or mastectomy has become an important rehabilitation process for breast cancer patients. This study aimed to provide an adipose tissue engineering platform for soft-tissue defect repair by combining decellularized human adipose tissue extracellular matrix (hDAM) and human adipose-derived stem cells (hASCs). To derive hDAM, incised human adipose tissues underwent a decellularization process. Effective cell removal and lipid removal were proved by immunohistochemical analysis and DNA quantification. Scanning electron microscope examination showed three-dimensional nanofibrous architecture in hDAM. hDAM composition included collagen, sulfated glycosaminoglycan, and vascular endothelial growth factor but lacked major histocompatibility complex antigen I. hASC viability and proliferation on hDAM were proven in vitro. hDAM implanted subcutaneously in Fischer rats did not cause an immunogenic response, and it underwent remodeling as indicated by host cell infiltration, neovascularization, and adipose tissue formation. Fresh fat grafts (Coleman technique) and engineered fat grafts (hDAM combined with hASCs) were implanted subcutaneously in nude rats. The implanted engineered fat grafts maintained volume at week 8, and the hASCs contributed to adipose tissue formation. In summary, the combination of hDAM and hASCs provides not only a clinically translatable platform for adipose tissue engineering but also a vehicle for elucidating fat grafting mechanisms.

The molecular mechanisms whereby hyperbaric oxygen (HBO) improves ischemic wound healing remain elusive. In this study, a rat model of wound ischemia was used to test the hypothesis that HBO enhances wound healing by modulating hypoxia-inducible factor-1alpha (HIF-1alpha) signaling. Male Sprague-Dawley rats underwent creation of a previously validated ischemic flap. Three groups underwent daily treatment: HBO (90 minutes, 2.4 atm); systemic administration of the free radical scavenger, N-acetylcysteine (NAC 150 mg kg(-1) intraperitoneal); control (neither HBO nor NAC). HBO treatment improved healing of the ischemic wounds. Analysis of ischemic wound tissue extracts demonstrated significantly reduced expression of HIF-1alpha, p53, and BNip3. Additionally, HBO increased expression of Bcl-2 while decreasing cleaved caspase-3. DNA fragmentation was abolished and the number of TUNEL-positive cells was reduced compared to the other groups. Vascular endothelial growth factor, cyclooxygenase-2, and neutrophil infiltration were reduced in ischemic wounds treated with HBO. These results indicate that HBO improves ischemic wound healing by downregulation of HIF-1alpha and subsequent target gene expression with attenuation of cell apoptosis and reduction of inflammation.

Using a perfusion decellularization protocol, we developed a decellularized skin/adipose tissue flap (DSAF) comprising extracellular matrix (ECM) and intact vasculature. Our DSAF had a dominant vascular pedicle, microcirculatory vascularity, and a sensory nerve network and retained three-dimensional (3D) nanofibrous structures well. DSAF, which was composed of collagen and laminin with well-preserved growth factors (e.g., vascular endothelial growth factor, basic fibroblast growth factor), was successfully repopulated with human adipose-derived stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs), which integrated with DSAF and formed 3D aggregates and vessel-like structures in vitro. We used microsurgery techniques to re-anastomose the recellularized DSAF into nude rats. In vivo, the engineered flap construct underwent neovascularization and constructive remodeling, which was characterized by the predominant infiltration of M2 macrophages and significant adipose tissue formation at 3 months postoperatively. Our results indicate that DSAF co-cultured with hASCs and HUVECs is a promising platform for vascularized soft tissue flap engineering. This platform is not limited by the flap size, as the entire construct can be immediately perfused by the recellularized vascular network following simple re-integration into the host using conventional microsurgical techniques.

Decellularized tracheal matrix scaffold did not induce significant allograft rejection or foreign body reaction in vivo. Although the construct supported reepithelialization, stem cell-derived chondrocytes failed to engraft in the heterotopic environment and represent a focus of future investigations.

Background The benefits of radiotherapy (RT) for cancer have been well documented for many years. However, even with targeted radiation delivery, many patients treated with radiation develop adverse effects. The purpose of this review was to analyze the current research into the biological basis of RT-induced normal tissue damage. Methods The PubMed and EMBASE databases were reviewed for articles on adverse effects of RT on normal tissue published from January 2005 through May 2012. Subsequently, abstracts of these articles were reviewed to identify articles with information relevant to the biological basis of RT-induced DNA damage and DNA repair. In addition, reference lists of the articles identified by the database search were reviewed, and referenced articles that seemed relevant were reviewed with no limitations on publication date. Results The database searches yielded 1751 publications. Of these, 1729 were eliminated because they did not address fundamental biology or were duplicates. A total of 22 articles were included. These articles revealed that many adverse effects are driven by chronic oxidative stress that affects the nuclear function of DNA repair mechanisms. Among normal cells undergoing replication, cells in S phase are most radioresistant because of overexpression of DNA repair enzymes, while cells in M phase are especially radiosensitive. Cancer cells exhibit increased radiosensitivity due to a breakdown in cell cycle checkpoints and repair mechanisms, and this increased radiosensitivity leads to accumulation of irreparable DNA lesions and cell death. Irradiated cells have an indirect effect on the cell cycle and survival of co-cultured non-irradiated cells. Method of irradiation and linear energy transfer to cancer cells versus bystander cells is shown to have an effect on cell survival, both cancerous and healthy. Conclusions RT-induced increases in reactive oxygen species in irradiated cells may signal healthy cells by increasing metabolic stress and creating DNA lesions. While normal cells express a strong ability to repair RT-induced DNA lesions, the side effects of RT and bystander cell signaling may have a larger impact than previously acknowledged.

Adipose-derived mesenchymal stem cells (ADSCs) show considerable promise for clinical applications in regenerative medicine. We performed a large-scale single-cell transcriptomic sequencing of 24,358 cultured human ADSCs from three donors. We provide a high-quality dataset, which would be a valuable resource for dissecting the intrapopulation heterogeneity of cultured ADSCs as well as interrogating lineage priming patterns for any interested lineages at single-cell resolution.

Ideal scaffolds that represent native extracellular matrix (ECM) properties of musculofascial tissues have great importance in musculofascial tissue engineering. However, detailed characterization of musculofascial tissues’ ECM (particularly, of fascia) from large animals is still lacking. In this study, we developed a decellularization protocol for processing pig composite musculofascial tissues. Decellularized muscle (D-muscle) and decellularized fascia (D-fascia), which are two important components of decellularized musculofascial extracellular matrix (DMM), were comprehensively characterized. D-muscle and D-fascia retained intact three-dimensional architecture, strong mechanical properties, and bioactivity of compositions such as collagen, laminin, glycosaminoglycan, and vascular endothelial growth factor. D-muscle and D-fascia provided a compatible niche for human adipose-derived stem cell integration and proliferation. Heterotopic and orthotopic implantation of D-muscle and D-fascia in a rodent model further proved their biocompatibility and myogenic properties during the remodeling process. The differing characteristics of D-muscle from D-fascia (e.g., D-muscle’s strong pro-angiogenic and pro-myogenic properties vs. D-fascia’s strong mechanical properties) indicate different clinical application opportunities of D-muscle vs. D-fascia scaffolds. DMM comprising muscle and fascia ECM as a whole unit can thus provide not only a clinically translatable platform for musculofascial tissue repair and regeneration but also a useful standard for scaffold design in musculofascial tissue engineering.