Faculty Bibliography

Once activated at the surface of cells, G protein-coupled receptors (GPCRs) redistribute to endosomes, where they can continue to signal. Whether GPCRs in endosomes generate signals that contribute to human disease is unknown. We evaluated endosomal signaling of protease-activated receptor-2 (PAR₂), which has been proposed to mediate pain in patients with irritable bowel syndrome (IBS). Trypsin, elastase, and cathepsin S, which are activated in the colonic mucosa of patients with IBS and in experimental animals with colitis, caused persistent PAR₂-dependent hyperexcitability of nociceptors, sensitization of colonic afferent neurons to mechanical stimuli, and somatic mechanical allodynia. Inhibitors of clathrin- and dynamin-dependent endocytosis and of mitogen-activated protein kinase kinase-1 prevented trypsin-induced hyperexcitability, sensitization, and allodynia. However, they did not affect elastase- or cathepsin S-induced hyperexcitability, sensitization, or allodynia. Trypsin stimulated endocytosis of PAR₂, which signaled from endosomes to activate extracellular signal-regulated kinase. Elastase and cathepsin S did not stimulate endocytosis of PAR₂, which signaled from the plasma membrane to activate adenylyl cyclase. Biopsies of colonic mucosa from IBS patients released proteases that induced persistent PAR₂-dependent hyperexcitability of nociceptors, and PAR₂ association with β-arrestins, which mediate endocytosis. Conjugation to cholestanol promoted delivery and retention of antagonists in endosomes containing PAR₂ A cholestanol-conjugated PAR₂ antagonist prevented persistent trypsin- and IBS protease-induced hyperexcitability of nociceptors. The results reveal that PAR₂ signaling from endosomes underlies the persistent hyperexcitability of nociceptors that mediates chronic pain of IBS. Endosomally targeted PAR₂ antagonists are potential therapies for IBS pain. GPCRs in endosomes transmit signals that contribute to human diseases.

Angiogenesis is a critical aspect of wound healing. We investigated the role of keratinocytes in promoting angiogenesis in mice with lineage specific deletion of the transcription factor FOXO1. The results indicate that keratinocyte-specific deletion of Foxo1 reduces VEGFA expression in mucosal and skin wounds and leads to the reduced endothelial cell proliferation, reduced angiogenesis and impaired re-epithelialization and granulation tissue formation. In vitro FOXO1 was needed for VEGFA transcription and expression. In a porcine dermal wound healing model that closely resembles healing in humans, local application of a FOXO1 inhibitor reduced angiogenesis. This is the first report that FOXO1 directly regulates VEGFA expression and that FOXO1 is needed for normal angiogenesis during wound healing.

The population is aging, and the prevalence of chronic wounds is increasing. Because neovascularization is essential for tissue repair and both local and systemic factors affect new blood vessel formation, we hypothesize that altering either pathway would reciprocally enhance wound healing in the aged. To test this hypothesis, p53 was locally suppressed and endothelial progenitor cells (EPCs) were systemically mobilized in a murine model of senescent wound healing.Bilateral 6-mm full-thickness stented wounds were made on the dorsum of Zmpste24 mice. Animals received weekly topical p53 small interfering RNA (siRNA) (n = 25), weekly topical nonsense siRNA (n = 25), daily subcutaneous AMD3100 injections (n = 25), or daily subcutaneous saline injections (n = 25). Wounds were photographically assessed and harvested for reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assay, and immunostaining over 40 days. Circulating EPC levels were measured using fluorescence-activated cell sorting analysis.Local p53 siRNA significantly improved Zmpste24 wound healing (18 ± 2 vs 40 ± 3 days; P ≤ 0.0001). p53 siRNA significantly increased local provasculogenic factors (hypoxia-inducible factor 1 α, stromal cell-derived factor 1 α, and vascular endothelial growth factor; P ≤ 0.05) and decreased local proapoptotic factors (p53, PUMA, and Bax; P ≤ 0.05). Local p53 siRNA also significantly increased the number of circulating EPCs (8 ± 0.2% vs 2.6 ± 0.1%; P ≤ 0.0001). AMD3100 treatment also significantly improved wound healing (20 ± 2 vs 40 ± 3 days; P ≤ 0.0001) and increased EPCs mobilization (7.8 ± 0.4% vs 2.6 ± 0.1%; P ≤ 0.0001). In addition, systemic AMD3100 increased local provasculogenic factors (hypoxia-inducible factor 1 α, stromal cell-derived factor 1 α, and vascular endothelial growth factor; P ≤ 0.05) and decreased local proapoptotic factors (p53, PUMA, and Bax; P ≤ 0.05). Both treatments significantly increased the number of blood vessels in the wound bed (P ≤ 0.0001).The marked delay in Zmpste24 wound healing is significantly improved by local (p53 siRNA) and systemic (AMD3100) treatments. The resulting decrease in proapoptotic factors and increase in provasculogenic factors in the wound bed as well as the increased level of circulating EPCs appear to reverse age-related wound healing impairment by enhancing wound neovascularization.

PURPOSE/OBJECTIVE:Free tissue transfer after lower extremity trauma is associated with notoriously high complication rates. Theoretically, the inclusion of a cutaneous paddle on muscle free flaps may improve clinical flap monitoring. The effect of skin paddle presence on muscle free flap salvage outcomes after take-back was examined. METHODS:Retrospective query of our institutional free-flap registry (1979-2016) identified 362 muscle-based flaps performed for soft tissue coverage after below-knee trauma. Primary outcome measures were perioperative complications, specifically take-back indications, timing, and flap salvage rates. Univariate and multivariate regression analyses were performed where appropriate. RESULTS:The most common flaps were latissimus dorsi (166; 45.9%), rectus abdominis (123; 34%), and gracilis (42; 11.6%) with 90 flaps (24.9%) including skin paddles. Take-backs for vascular compromise occurred in 44 flaps (12.2%), of which 39% contained a skin paddle while 61% did not. Overall salvage rate was 20.5%, with 31.8% partial failures and 47.7% total flap losses. Muscle flaps with skin paddles were more likely to return to the operating room within 48 hours postoperatively than those without (57.1% vs 18.2%, P = 0.036). After take-back, significantly more muscle flaps with skin paddles were salvaged compared with muscle flaps without paddles (35.7% vs 4.5%, P = 0.024). Similarly, more muscle-only flaps after take-back failed compared with their counterparts with skin paddles (95.5% vs 65.3%, P = 0.024). CONCLUSIONS:Muscle flaps with a cutaneous paddle were associated with earlier return to the operating room and more successful flap salvage after take-back compared with muscle-only flaps. These findings suggest that skin paddle presence may improve clinical flap monitoring and promote recognition and treatment of microvascular compromise in lower extremity reconstruction.

The current U.S. demographic shift toward an older population and the importance of intervening before conditions become severe warrant a concerted effort to ease the burden of access to healthcare for older adults. With regard to oral healthcare, more integrated services for older adults are needed to effectively serve their complex medical and dental needs. Using an agent-based simulation model, this paper examines the influence of social ties and transportation mode choices on opportunities for older adults to participate in community-based preventive screening events and access needed oral healthcare. This approach accounts for the heterogeneity of behavior that arises for a population exhibiting diversity in terms of social factors, including socioeconomic means and social support. In the context of older adults living in urban environments, the availability of different transportation modes ought to be taken into consideration. To explore alternative scenarios for the accessibility of preventive screening events offered at senior centers in northern Manhattan, an agent-based model (ABM) was created with a geographic information system (GIS) to simulate the influence of social ties and transportation choices on older adults seeking preventive screening services and oral healthcare. Results of simulation experiments indicate preferences for public transportation and inequities in accessibility that may be mitigated with social support. This simulation model offers a way to explore social support as an important factor in making transportation mode choices that mediate oral healthcare accessibility and thus oral health outcomes for older adults.

INTRODUCTION: Innervated muscle transfer can improve functional outcomes after extensive limb-sparing sarcoma resections. We report our experience using composite thigh flaps for functional reconstruction of large oncologic extremity defects. PATIENTS AND METHODS: Between 2011 and 2014, four limb-sparing oncologic resections (3 lower extremities, 1 upper extremity) underwent immediate functional reconstruction with composite thigh free flaps in three males and one female. The age of the patients ranged from 36 to 73 years. There were 3 soft-tissue sarcomas and one giant cell tumor, all required resection of entire muscle compartments. Flap components included fasciocutaneous tissue with sensory nerve, plicated iliotibial band (ITB), and variable amounts of motorized vastus lateralis (VL). RESULTS: All flaps survived without complications. All patients showed VL motor innervation by six months. Follow-up ranged from 20 to 36 months. Motor strength ranged from 2 to 5 out of 5, active range of motion was 25-92% of normal, and Musculoskeletal Tumor Society (MSTS) Scores were between 22 and 29 out of 30. CONCLUSIONS: Limb-sparing techniques for upper and lower extremity sarcomas continue to evolve. Our experience has validated the composite thigh free flap as an excellent option for one-stage functional reconstruction of large limb defects.

STATEMENT OF PROBLEM/BACKGROUND:Multiple definitions of centric relation (CR) have evolved over time that may have created confusion or impeded understanding. A recent attempt to achieve a singular definition by surveying the members of the Academy of Prosthodontics (AP) did not achieve majority consensus. PURPOSE/OBJECTIVE:The purpose of this study was to identify those aspects or attributes within the existing definitions of CR in which there was agreement or disagreement among the members of the AP. MATERIAL AND METHODS/METHODS:After pretesting and institutional review board approval, a second survey of the AP membership was performed using both email and postal mail survey methods of contact. The CR Attributes Survey separated and stratified the previous definitions of CR into 5 domains: spatial relationship, condylar position, articular disks, mandibular movement, and recording. Each domain attribute was evaluated by agree-uncertain-disagree assessments. Also recorded were demographics, perception of scientific evidence, and open comments. RESULTS:Of the total 146 fellows, 100 completed the survey for an overall response rate of 68.5%. The query completion rate ranged from 96% to 98%. The CR Attributes Survey revealed those components within each domain in which there was strong agreement, disagreement, or uncertainty. The survey assessment of those queries with a moderate to strong agreement were that CR is a "spatial relationship" that is (1) a clinically determined relationship of the mandible to the maxilla, (2) a repeatable position, (3) is independent of tooth contact, and (4) is a physiologic position. Relative to "disks," the condyles articulate with the thinnest avascular intermediate zone of their respective disks; however, there is a lack of sufficient evidence to determine the position of the disks and the condyles. Relative to "mandibular movement," CR is (1) a starting point for vertical, lateral, or protrusive movements, (2) is where the individual can make to and from lateral movements, and (3) is restricted to pure rotary movement about a transverse horizontal axis. Relative to "recording CR" (1) it can be determined in patients without pain or derangement of the temporomandibular joints (TMJs), (2) but may not be recordable in the presence of dysfunction of the masticatory system, or (3) due to the neuromuscular influence or proprioception from the dentition, (4) is a clinical useful repeatable reference position for mounting casts, or (5) for developing a functional treatment occlusion, (6) at an established vertical dimension, and (7) may vary slightly by recording method. CONCLUSIONS:The CR Attributes Survey revealed a majority agreement or consensus for various CR attributes that should be considered for defining the term 'centric relation.' In contrast, those CR attributes with a plurality agreement, disagreement, or uncertainty outcomes should be considered for exclusion. The evaluated weakness of these latter attributes indicates the need for further research and reassessment.

This article focuses on flap-related complications after creation of a neophallus for transgender individuals. It outlines the most frequently used flaps for this procedure and how flap-related complications can affect the overall outcome of the phalloplasty. With surgeons staging the procedure in different stages, it is important to understand the different strategies and the implication a flap-related complication can have on the end result and how it may be prevented.

Ionizing radiation is a known carcinogen. Its damaging effects can be deterministic or stochastic. Deterministic effects occur only after radiation exposure thresholds are reached, but stochastic effects are random, and there is no known threshold below which harmful effects will not occur. Therefore, the use of ionizing radiation in orthodontic treatment should bring a benefit to the patient that outweighs the risks. No legally binding statutes, rules, or regulations provide explicit radiographic prescription protocols for orthodontic practice. The objective of this article was to discuss guidelines and risk management strategies for appropriate and defensible use of ionizing radiation in orthodontics. Guidelines are discussed for radiographic acquisition at different points along the orthodontic treatment timeline. In addition, risk management strategies and best practices are presented regarding adequate and defensible radiographic interpretation. These guidelines are not rigid and do not establish standards of care; they should be modified as necessary for each patient and each clinical encounter.

Current pharmacologic regimens in transplantation prevent allograft rejection through systemic recipient immunosuppression but are associated with severe morbidity and mortality. The ultimate goal of transplantation is the prevention of allograft rejection while maintaining recipient immunocompetence. We hypothesized that allografts could be engineered ex vivo (after allotransplant procurement but before transplantation) by using mesenchymal stem cell-based therapy to generate localized immunomodulation without affecting systemic recipient immunocompetence. To this end, we evaluated the therapeutic efficacy of bone marrow-derived mesenchymal stem cells in vitro and activated them toward an immunomodulatory fate by priming in inflammatory or hypoxic microenvironments. Using an established rat hindlimb model for allotransplantation, we were able to significantly prolong rejection-free allograft survival with a single perioperative ex vivo infusion of bone marrow-derived mesenchymal stem cells through the allograft vasculature, in the absence of long-term pharmacologic immunosuppression. Critically, transplanted rats rejected a second, nonengineered skin graft from the same donor species to the contralateral limb at a later date, demonstrating that recipient systemic immunocompetence remained intact. This study represents a novel approach in transplant immunology and highlights the significant therapeutic opportunity of the ex vivo period in transplant engineering.