Faculty Bibliography

BACKGROUND: : Lipoaspirate centrifugation creates graded density of adipose tissue. High-density fat contains more vasculogenic cytokines and progenitor cells and has greater graft survival than low-density fat. The authors hypothesize that accelerating the bone marrow-derived progenitor cell response to injected low-density fat will improve its graft survival. METHODS: : Male 8-week-old FVB mice (n = 60) were grafted with either high-density (n = 20) or low-density (n = 40) human lipoaspirate. Half of the mice receiving low-density fat (n = 20) were treated with a stem cell mobilizer for 14 days. Grafted fat was harvested at 2 and 10 weeks for analysis. RESULTS: : Low-density fat, low-density fat plus daily AMD3100, and high-density fat had 26 +/- 3.0, 61.2 +/- 7.5, and 49.6 +/- 3.5 percent graft survival, respectively, at 2 weeks (low-density fat versus low-density fat plus daily AMD3100 and low-density fat versus high-density fat, both p < 0.01). Similar results were observed 10 weeks after grafting. Mice receiving low-density fat plus daily AMD3100 had significantly more vasculogenic progenitor cells per cubic centimeter of peripheral blood (p < 0.01) and more new blood vessels (p < 0.01). Both low-density fat plus daily AMD3100 and high-density fat contained more stromal-derived factor-1alpha and vascular endothelial growth factor mRNA/protein. CONCLUSION: : Endogenous progenitor cell mobilization enhances low-density fat neovascularization, increases vasculogenic cytokine expression, and improves graft survival to a level equal to that of high-density fat grafts.

A serious consequence of diabetes mellitus is impaired wound healing, which largely resists treatment. We previously reported that topical application of calreticulin (CRT), an endoplasmic reticulum chaperone protein, markedly enhanced the rate and quality of wound healing in an experimental porcine model of cutaneous repair. Consistent with these in vivo effects, in vitro CRT induced the migration and proliferation of normal human cells critical to the wound healing process. These functions are particularly deficient in poor healing diabetic wounds. Using a genetically engineered diabetic mouse (db/db) in a full-thickness excisional wound healing model, we now show that topical application of CRT induces a statistically significant decrease in the time to complete wound closure compared with untreated wounds by 5.6 days (17.6 vs. 23.2). Quantitative analysis of the wounds shows that CRT increases the rate of reepithelialization at days 7 and 10 and increases the amount of granulation tissue at day 7 persisting to day 14. Furthermore, CRT treatment induces the regrowth of pigmented hair follicles observed on day 28. In vitro, fibroblasts isolated from diabetic compared with wild-type mouse skin and human fibroblasts cultured under hyperglycemic compared with normal glucose conditions proliferate and strongly migrate in response to CRT compared with untreated controls. The in vitro effects of CRT on these functions are consistent with CRT's potent effects on wound healing in the diabetic mouse. These studies implicate CRT as a potential powerful topical therapeutic agent for the treatment of diabetic and other chronic wounds.

BACKGROUND: Frontal sinus cranialization is commonly indicated for posterior table fractures with significant comminution, displacement, or cerebrospinal fluid leaks. This study assessed the clinical outcomes of conservative management. METHODS: A 10-year retrospective review of all frontal sinus fractures treated at a level 1 trauma center was performed using medical records and radiographic images. RESULTS: A total of 875 patients with frontal sinus fractures were identified, and 68 had posterior table involvement. Nine died within the first 48 hours from other injuries. The remaining 59 patients constituted the study population. Average follow-up approached 1 year (342 days). The more common mechanisms of injury were blunt interpersonal violence (29 percent) and motor vehicle accidents (27 percent). Concurrent central nervous system injury was common (73 percent), and the average Glasgow Coma Scale score was 12.7. Posterior wall fracture pattern was nondisplaced and noncomminuted in 33 patients (54 percent) and comminuted and/or displaced in 27 (46 percent). Cerebrospinal fluid leak was recorded in 11 patients (19 percent). Conservative management was the more common strategy (78 percent), followed by open reduction and internal fixation with sinus preservation (12 percent), obliteration (8 percent), and cranialization (2 percent). Of the 27 patients with comminuted and/or displaced fractures, 16 (59 percent) underwent conservative management, and 11 (41 percent) underwent surgical management, but only one patient (2 percent) underwent cranialization. There was no incidence of intracranial infection, except for one patient who died from encephalitis secondary to a gunshot wound to the head. CONCLUSION: The vast majority of frontal sinus fractures involving the posterior table, including those with comminution, displacement, or cerebrospinal fluid leaks, can be safely managed without cranialization. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Repair of full thickness defects in the lower eyelid following extirpation of malignant tumors presents a challenge to the reconstructive surgeon. There are several techniques to choose from, depending on the defect's size and location.

Sweat glands are abundant in the body and essential for thermoregulation. Like mammary glands, they originate from epidermal progenitors. However, they display few signs of cellular turnover, and whether they have stem cells and tissue-regenerative capacity remains largely unexplored. Using lineage tracing, we here identify in sweat ducts multipotent progenitors that transition to unipotency after developing the sweat gland. In characterizing four adult stem cell populations of glandular skin, we show that they display distinct regenerative capabilities and remain unipotent when healing epidermal, myoepithelial-specific, and lumenal-specific injuries. We devise purification schemes and isolate and transcriptionally profile progenitors. Exploiting molecular differences between sweat and mammary glands, we show that only some progenitors regain multipotency to produce de novo ductal and glandular structures, but that these can retain their identity even within certain foreign microenvironments. Our findings provide insight into glandular stem cells and a framework for the further study of sweat gland biology.

This study investigated the effect of an Argon-based atmospheric pressure plasma (APP) surface treatment operated chairside at atmospheric pressure conditions applied immediately prior to dental implant placement in a canine model. Surfaces investigated comprised: rough titanium surface (Ti) and rough titanium surface + Argon-based APP (Ti-Plasma). Surface energy was characterized by the Owens-Wendt-Rabel-Kaelble method and chemistry by X-ray photoelectron spectroscopy (XPS). Six adult beagles dogs received two plateau-root form implants (n = 1 each surface) in each radii, providing implants that remained 1 and 3 weeks in vivo. Histometric parameters assessed were bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Statistical analysis was performed by Kruskall-Wallis (95% level of significance) and Dunn's post-hoc test. The XPS analysis showed peaks of Ti, C, and O for the Ti and Ti- Plasma surfaces. Both surfaces presented carbon primarily as hydrocarbon (C-C, C-H) with lower levels of oxidized carbon forms. The Ti-Plasma presented large increase in the Ti (+11%) and O (+16%) elements for the Ti- Plasma group along with a decrease of 23% in surface-adsorbed C content. At 1 week no difference was found in histometric parameters between groups. At 3 weeks significantly higher BIC (>300%) and mean BAFO (>30%) were observed for Ti-Plasma treated surfaces. From a morphologic standpoint, improved interaction between connective tissue was observed at 1 week, likely leading to more uniform and higher bone formation at 3 weeks for the Ti-Plasma treated implants was observed.

We propose the profunda femoris artery perforator (PAP) flap for autologous breast reconstruction. We provide an anatomic basis for this flap. Ten cadaveric thighs were dissected. A perforator was dissected to its origin. The lengths of pedicle, vessel diameters, and weights were measured. The average distance inferior to the gluteal crease was 3.5 cm (1 to 5 cm). The average distance from the midline was 6.2 cm (3 to 12 cm). The average pedicle length was 10.6 cm. Diameters of the artery and vein averaged 2.3 mm and 2.8 mm. The flaps averaged 28 x 8 cm. The average weight was 206 g (100 to 260 g). Computed tomography angiograms of 20 thighs were examined. Measurements were taken from the gluteal crease and midline to the perforator. The average distance caudal to the gluteal crease was 4.4 cm (1.1 to 7.2 cm). The average distance lateral to the midline was 5.1 cm (2.5 to 9 cm). The data presented in this article provide an anatomic basis for the PAP flap.