BACKGROUND:: Lipoaspirate centrifugation creates graded density of adipose tissue. Higher density (HD) fat contains more vasculogenic cytokines and progenitor cells (PCs) and greater graft survival than lower density (LD) fat. We hypothesize that accelerating the bone marrow-derived PC response to injected LD fat will improve its graft survival. METHODS:: Male 8-week old FVB mice (n=60) were grafted with either HD (n=20) or LD (n=40) human lipoaspirate. Half of the LD mice (n=20) were treated with a stem cell mobilizer (LD) for 14 days. Grafted fat was harvested at 2 and 10 weeks to determine percent survival as well as perform immunohistochemistry, flow cytometry, qRT-PCR, and ELISA analyses. RESULTS:: LD, LD and HD fat had 26 ± 3.0, 61.2 ± 7.5, 49.6 ± 3.5% graft survival at 2 weeks (LD v. LD and LD v. HD both p<0.01; LD v. HD were not different). Similar results were observed 10 weeks after grafting. LD mice had significantly more vasculogenic PCs/cc of peripheral blood (p<0.01) and more new blood vessels (p<0.01) in the grafted fat compared to HD or LD mice. Both LD and HD fat contained more SDF-1α and VEGF mRNA/protein than LD fat at 2 and 10 weeks.(LD v. LD and LD v. HD both p<0.01; LD v. HD were not different). CONCLUSIONS:: Endogenous progenitor cell mobilization enhances LD fat neovascularization, increases vasculogenic cytokine expression, and improves graft survival to a level equal to HD fat grafts.

BACKGROUND: Fat grafting has been shown clinically to improve the quality of burn scars. To date, no study has explored the mechanism of this effect. We aimed to do so by combining our murine model of fat grafting with a previously described murine model of thermal injury. METHODS: Wild-type FVB mice (n=20) were anaesthetised, shaved and depilitated. Brass rods were heated to 100°C in a hot water bath before being applied to the dorsum of the mice for 10s, yielding a full-thickness injury. Following a 2-week recovery period, the mice underwent Doppler scanning before being fat/sham grafted with 1.5cc of human fat/saline. Half were sacrificed 4 weeks following grafting, and half were sacrificed 8 weeks following grafting. Both groups underwent repeat Doppler scanning immediately prior to sacrifice. Burn scar samples were taken following sacrifice at both time points for protein quantification, CD31 staining and Picrosirius red staining. RESULTS: Doppler scanning demonstrated significantly greater flux in fat-grafted animals than saline-grafted animals at 4 weeks (fat=305±15.77mV, saline=242±15.83mV; p=0.026). Enzyme-linked immunosorbent assay (ELISA) analysis in fat-grafted animals demonstrated significant increase in vasculogenic proteins at 4 weeks (vascular endothelial growth factor (VEGF): fat=74.3±4.39ngml(-1), saline=34.3±5.23ngml(-1); p=0.004)(stromal cell-derived factor-1 (SDF-1): fat=51.8±1.23ngml(-1), saline grafted=10.2±3.22ngml(-1); p<0.001) and significant decreases in fibrotic markers at 8 weeks (transforming growth factor-ß1(TGF-ß): saline=9.30±0.93, fat=4.63±0.38ngml(-1); p=0.002)(matrix metallopeptidase 9 (MMP9): saline=13.05±1.21ngml(-1), fat=6.83±1.39ngml(-1); p=0.010). CD31 staining demonstrated significantly up-regulated vascularity at 4 weeks in fat-grafted animals (fat=30.8±3.39 vessels per high power field (hpf), saline=20.0±0.91 vessels per high power field (hpf); p=0.029). Sirius red staining demonstrated significantly reduced scar index in fat-grafted animals at 8 weeks (fat=0.69±0.10, saline=2.03±0.53; p=0.046). CONCLUSIONS: Fat grafting resulted in more rapid revascularisation at the burn site as measured by laser Doppler flow, CD31 staining and chemical markers of angiogenesis. In turn, this resulted in decreased fibrosis as measured by Sirius red staining and chemical markers.

BACKGROUND Autogenous fat grafting has been observed to alleviate the sequelae of chronic radiodermatitis. To date, no study has replicated this finding in an animal model. METHODS The dorsa of adult wild-type FVB mice were shaved and depilated. The dorsal skin was then distracted away from the body and irradiated (45 Gy). Four weeks after irradiation, 1.5-cc fat or sham grafts were placed in the dorsal subcutaneous space. Gross results were analyzed photometrically. The animals were euthanized at 4 and 8 weeks after fat or sham grafting and their dorsal skin was processed for histologic analysis. RESULTS Hyperpigmentation and ulceration were grossly improved in fat-grafted mice compared with sham-grafted controls. This improvement manifested histologically in a number of ways. For example, epidermal thickness measurements demonstrated decreased thickness in fat-grafted animals at both time points (20.6 ± 1.5 μm versus 55.2 ± 5.6 μm, p = 0.004; 17.6 ± 1.1 μm versus 36.3 ± 6.1 μm, p = 0.039). Picrosirius red staining demonstrated a diminished scar index in fat-treated animals at both time points as well (0.54 ± 0.05 versus 0.74 ± 0.07, p = 0.034; and 0.55 ± 0.06 versus 0.93 ± 0.07, p = 0.001). CONCLUSION Fat grafting attenuates inflammation in acute radiodermatitis and slows the progression of fibrosis in chronic radiodermatitis.

Radiation therapy is a cornerstone of oncologic treatment. Skin tolerance is often the limiting factor in radiotherapy. To study these issues and create modalities for intervention, the authors developed a novel murine model of cutaneous radiation injury. The dorsal skin was isolated using a low-pressure clamp and irradiated. Mice were followed for 8 weeks with serial photography and laser Doppler analysis. Sequential skin biopsy specimens were taken and examined histologically. Tensiometry was performed and Young's modulus calculated. High-dose radiation isolated to dorsal skin causes progressive changes in skin perfusion, resulting in dermal thickening, fibrosis, persistent alopecia, and sometimes ulceration. There is increased dermal Smad3 expression, and decreased elasticity and bursting strength. This model of cutaneous radiation injury delivers reproducible localized effects, mimicking the injury pattern seen in human subjects. This technique can be used to study radiation-induced injury to evaluate preventative and therapeutic strategies for these clinical issues.

The viability of fat grafts harvested with an established technique after cryopreservation remains unknown. This study was conducted in vitro to evaluate the viability of autologous fat grafts harvested with the Coleman technique and subsequently preserved with our preferred cryopreservation method. Eight adult females were enrolled in this study. In each patient, 10 mL of fat grafts were harvested with the Coleman technique by a single surgeon from the lower abdomen. In group 1, 5 mL of fresh fat grafts were mixed with cryoprotective agents and underwent cryopreservation with controlled slow cooling and fast rewarming. In group 2, 5 mL of fresh fat grafts without cryopreservation from the same patient served as a control. The fat graft samples from both groups were evaluated with trypan blue vital staining, glycerol-3-phophatase dehydrogenase assay, and routine histology. Viable adipocyte counts were found similar in both group 1 and group 2 (3.46 +/- 0.91 vs. 4.12 +/- 1.11 x 10/mL, P = 0.22). However, glycerol-3-phophatase dehydrogenase activity was significantly lower in group 1 compared with group 2 (0.47 +/- 0.09 vs. 0.66 +/- 0.09 u/mL, P < 0.001). Histologically, the normal structure of fragmented fatty tissues was found primarily in both groups. Our results indicate that autologous fat grafts harvested with the Coleman technique and preserved with our preferred cryopreservation method have a normal histology with near the same number of viable adipocytes as compared with the fresh fat grafts. However, those cryopreserved fat grafts appear to have a less optimal level of adipocyte specific enzyme activity compared with the fresh ones and thus may not survive well after they are transplanted without being optimized.

BACKGROUND: The study of human autologous fat grafting has been primarily anecdotal. In this study, the authors aim to develop a murine model that recapitulates human fat grafting to study the fate of injected fat and the cell populations contained within. METHODS: The authors' method of fat harvesting and refinement has been described previously. The authors injected nude and tie2/lacZ mice with 2 ml of human lipoaspirate placed on the dorsal surface in a multipass, fan-like pattern. Fatty tissue was injected in small volumes of approximately 1/30 ml per withdrawal. The dorsal skin and associated fat was excised at various time points. Sections were stained with hematoxylin and eosin and cytochrome c oxidase IV. Transgenic tie2/lacZ samples were stained with X-galactosidase. At the 8-week time point, volumetric analysis was performed. RESULTS: Volumetric analysis at the 8-week time point showed 82 percent persistence of the original volume. Gross analysis showed it to be healthy, nonfibrotic, and vascularized. Hematoxylin and eosin analysis showed minimal inflammatory or capsular reaction, with viable adipocytes. Fat grafted areas were vascularized with multiple blood vessels. Cytochrome c oxidase IV human-specific stain and beta-galactosidase expression revealed these vessels to be of human origin. CONCLUSIONS: The authors have developed a murine model with which to study the fate of injected lipoaspirate. There is a high level of persistence of the grafted human fat, with minimal inflammatory reaction. The fat is viable and vascularized, demonstrating human-derived vessels in a mouse model. This model provides a platform for studying the populations of progenitor cells known to reside in lipoaspirate.

Facial aging reflects the dynamic, cumulative effects of time on the skin, soft tissues, and deep structural components of the face, and is a complex synergy of skin textural changes and loss of facial volume. Many of the facial manifestations of aging reflect the combined effects of gravity, progressive bone resorption, decreased tissue elasticity, and redistribution of subcutaneous fullness. A convenient method for assessing the morphological effects of aging is to divide the face into the upper third (forehead and brows), middle third (midface and nose), and lower third (chin, jawline, and neck). The midface is an important factor in facial aesthetics because perceptions of facial attractiveness are largely founded on the synergy of the eyes, nose, lips, and cheek bones (central facial triangle). For aesthetic purposes, this area should be considered from a 3-dimensional rather than a 2-dimensional perspective, and restoration of a youthful 3-dimensional facial topography should be regarded as the primary goal in facial rejuvenation. Recent years have seen a significant increase in the number of nonsurgical procedures performed for facial rejuvenation. Patients seeking alternatives to surgical procedures include those who require restoration of lost facial volume, those who wish to enhance normal facial features, and those who want to correct facial asymmetry. Important factors in selecting a nonsurgical treatment option include the advantages of an immediate cosmetic result and a short recovery time.

In recent years, several cases of blindness, stroke, and skin necrosis have occurred after injection of soft tissue fillers. To avoid such complications, the author recommends using larger, blunt cannulas and epinephrine at the injection site, while avoiding the injection of large boluses of soft tissue filler in the face.(Aesthetic Surg J 2002;22:555-557.).

Although the FDA has never approved liquid silicone for cosmetic indications, some practitioners in the United States are purchasing liquid silicone oil, intended for treatment of retinal detachment, and injecting it for aesthetic purposes. The author discusses this off-label use and provides a historical context for the current FDA-approved clinical study of injectable silicone oil for soft tissue augmentation.(Aesthetic Surg J 2001;21:576-578.).