Administration of adipose-derived stem cells enhances vascularity, induces collagen deposition, and dermal adipogenesis in burn wounds.

Current treatment options for severe burn wounds are often insufficient in reconstructing skin and soft tissue defects. Adipose-derived stem cells (ASCs), a readily available source of multipotent stem cells, represent a promising therapy for the treatment of full-thickness burn wounds. Full-thickness burn wounds were created on the paraspinal region of athymic mice. A one-time, sub-eschar injection of 6.8×10(6) ASCs in PBS or PBS alone was administered at 24-h postoperatively. Time to healing was quantified using Image J analysis. At days 4, 7, 14, and 21, mice were sacrificed and tissues were excised for molecular and histological analysis. ASCs were able to survive in burn wounds as determined by the presence of PKH labeling and human PPARγ expression within the wounds. CD-31 staining demonstrated increased vascularity in ASC-treated wounds at POD 4 (p<0.05). Molecular studies showed enhanced adipogenesis, as well as type III and type I collagen deposition in the ASC treated group (p<0.05). An increase in the mRNA expression ratio of type III to type I collagen was also observed following ASC treatment (p<0.05). By enhancing vascularity, collagen deposition, and adipogenesis, ASCs show promise as an adjunctive therapy for the current treatment of full thickness burn wounds.

Imaging the Stromal Vascular Fraction during Soft-Tissue Reconstruction.

BACKGROUND: Although fat grafting is an increasingly popular practice, suboptimal volume retention remains an obstacle. Graft enrichment with the stromal vascular fraction has gained attention as a method of increasing graft retention. However, few studies have assessed the fate and impact of transplanted stromal vascular fraction on fat grafts. In vivo imaging techniques can be used to help determine the influence stromal vascular fraction has on transplanted fat. METHODS: Stromal vascular fraction was labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR), a near-infrared dye, and tracked in vivo. Proliferation and differentiation of labeled cells were assessed to confirm that labeling did not adversely affect cellular function. Different doses of labeled stromal vascular fraction were tracked within fat grafts over time using the in vivo imaging system. RESULTS: No significant differences in differentiation and proliferation were observed in labeled versus unlabeled cells (p > 0.05). A pilot study confirmed that stromal vascular fraction fluorescence was localized to fat grafts and different cell doses could be distinguished. A larger-scale in vivo study revealed that stromal vascular fraction fluorescence was statistically significant (p < 0.05) between different cell dose groups and this significance was maintained in higher doses (3 × 10(6) and 2 × 10(6) cells/ml of fat graft) for up to 41 days in vivo. CONCLUSIONS: DiR labeling allowed the authors to differentiate between cell doses and confirm localization. This article supports the use of DiR labeling in conjunction with in vivo imaging as a tool for imaging stromal vascular fraction within fat grafts.

Effects of immunosuppressive drugs on viability and susceptibility of adipose- and bone marrow-derived mesenchymal stem cells.

The immunomodulatory potential of cell therapies using adipose-derived stem cells (ASCs) and bone marrow-derived mesenchymal stem cells (BM-MSCs) has been studied in vascularized composite allotransplantation (VCA). Most cell therapy-based experimental and clinical protocols integrate some degree of recipient conditioning/induction with antibodies or other immunosuppressive agents. We investigated the susceptibility of ASCs and BM-MSCs to anti-lymphocyte serum (ALS) and tacrolimus. Rat ASCs and BM-MSCs were exposed to varying concentrations of tacrolimus and ALS in vitro. Serum from ALS-treated animals was added to cell cultures. Viability, susceptibility, and cytotoxicity parameters were evaluated. ALS inhibited ASC and BM-MSC viability and susceptibility in vitro in a dose-dependent manner. ASCs were more susceptible to both ALS and tacrolimus than BM-MSCs. Trypsinized and adherent ASCs were significantly smaller than BM-MSCs. This is the first report on the viability and susceptibility characteristics of BM-MSCs or ASCs to collateral effects of ALS and tacrolimus. These in vitro insights may impact choice of cell type as well as concomitant conditioning agents and the logistical coordination of the timing, dosing, and frequency of drug or cell therapy in solid organ transplantation or VCA protocols.

The use of adipose-derived stem cells as sheets for wound healing.

Cellular therapies have shown immense promise in the treatment of nonhealing wounds. Cell sheets are an emerging strategy in tissue engineering, and these cell sheets are promising as a delivery method of mesenchymal stem cells to the wound bed. Cell sheet technology utilizes temperature dependent polymers to allow for lifting of cultured cells and extracellular matrix without the use of digestive enzymes. While mesenchymal stem cells (MSCs) have shown success in cell sheets for myocardial repair, examination of cell sheets in the field of wound healing has been limited. We previously developed a novel cell sheet composed of human adipose-derived stem cells (ASCs). Both single and triple layer cell sheets were examined in a full-thickness murine wound model. The treatment cell sheets were compared with untreated controls and analyzed at timepoints of 7, 14, 18 and 21 d. The ASC cell sheets showed increased healing at 7, 14 and 18 d, and this effect was increased in the triple layer cell sheet group. Future development of these cell sheets will focus on increasing angiogenesis in the wound bed, utilizing multiple cell types, and examining allogeneic cell sheets. Here we review our experiment, expand upon our future directions and discuss the potential of an off-the-shelf cell sheet. In the field of wound healing, such a cell sheet is both clinically and scientifically exciting.

Persistent pain in postmastectomy patients: comparison of psychophysical, medical, surgical, and psychosocial characteristics between patients with and without pain.

Persistent postmastectomy pain (PPMP) is a major individual and public health problem. Increasingly, psychosocial factors such as anxiety and catastrophizing are being revealed as crucial contributors to individual differences in pain processing and outcomes. Furthermore, differences in patients' responses to standardized quantitative sensory testing (QST) may aid in the discernment of who is at risk for acute and chronic pain after surgery. However, characterization of the variables that differentiate those with PPMP from those whose acute postoperative pain resolves is currently incomplete. The purpose of this study was to investigate important surgical, treatment-related, demographic, psychophysical, and psychosocial factors associated with PPMP by comparing PPMP cases with PPMP-free controls. Pain was assessed using the breast cancer pain questionnaire to determine the presence and extent of PPMP. Psychosocial and demographic information were gathered via phone interview, and women underwent a QST session. Consistent with most prior research, surgical and disease-related variables did not differ significantly between cases and controls. Furthermore, treatment with radiation, chemotherapy, or hormone therapy was also not more common among those with PPMP. In contrast, women with PPMP did show elevated levels of distress-related psychosocial factors such as anxiety, depression, catastrophizing, and somatization. Finally, QST in nonsurgical body areas revealed increased sensitivity to mechanical stimulation among PPMP cases, while thermal pain responses were not different between the groups. These findings suggest that an individual's psychophysical and psychosocial profile may be more strongly related to PPMP than their surgical treatment.