Joshua A. David

Novel lipoproteoplex delivers Keap1 siRNA based gene therapy to accelerate diabetic wound healing

Therapeutics utilizing siRNA are currently limited by the availability of safe and effective delivery systems. Cutaneous diseases, specifically ones with significant genetic components are ideal candidates for topical siRNA based therapy but the anatomical structure of skin presents a considerable hurdle. Here, we optimized a novel liposome and protein hybrid nanoparticle delivery system for the topical treatment of diabetic wounds with severe oxidative stress. We utilized a cationic lipid nanoparticle (CLN) composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and the edge activator sodium cholate (NaChol), in a 6:1 ratio of DOTAP:NaChol (DNC). Addition of a cationic engineered supercharged coiled-coil protein (CSP) in a 10:1:1 ratio of DNC:CSP:siRNA produced a stable lipoproteoplex (LPP) nanoparticle, with optimal siRNA complexation, minimal cytotoxicity, and increased transfection efficacy. In a humanized murine diabetic wound healing model, our optimized LPP formulation successfully delivered siRNA targeted against Keap1, key repressor of Nrf2 which is a central regulator of redox mechanisms. Application of LPP complexing siKeap1 restored Nrf2 antioxidant function, accelerated diabetic tissue regeneration, and augmented reduction-oxidation homeostasis in the wound environment. Our topical LPP delivery system can readily be translated into clinical use for the treatment of diabetic wounds and can be extended to other cutaneous diseases with genetic components.

The Nrf2/Keap1/ARE Pathway and Oxidative Stress as a Therapeutic Target in Type II Diabetes Mellitus

Despite improvements in awareness and treatment of type II diabetes mellitus (TIIDM), this disease remains a major source of morbidity and mortality worldwide, and prevalence continues to rise. Oxidative damage caused by free radicals has long been known to contribute to the pathogenesis and progression of TIIDM and its complications. Only recently, however, has the role of the Nrf2/Keap1/ARE master antioxidant pathway in diabetic dysfunction begun to be elucidated. There is accumulating evidence that this pathway is implicated in diabetic damage to the pancreas, heart, and skin, among other cell types and tissues. Animal studies and clinical trials have shown promising results suggesting that activation of this pathway can delay or reverse some of these impairments in TIIDM. In this review, we outline the role of oxidative damage and the Nrf2/Keap1/ARE pathway in TIIDM, focusing on current and future efforts to utilize this relationship as a therapeutic target for prevention, prognosis, and treatment of TIID.

Microenvironmental cues enhance mesenchymal stem cell-mediated immunomodulation and regulatory T-cell expansion

Mesenchymal stem cells (MSCs) are known to both have powerful immunosuppressive properties and promote allograft tolerance. Determining the environmental oxygen tension and inflammatory conditions under which MSCs are optimally primed for this immunosuppressive function is essential to their utilization in promoting graft tolerance. Of particular interest is the mechanisms governing the interaction between MSCs and regulatory T cells (Tregs), which is relatively unknown. We performed our experiments utilizing rat bone marrow derived MSCs. We observed that priming MSCs in hypoxia promotes maintenance of stem-like characteristics, with greater expression of typical MSC cell-surface markers, increased proliferation, and maintenance of differentiation potential. Addition of autologous MSCs to CD4+/allogeneic endothelial cell (EC) co-culture increases regulatory T cell (Treg) proliferation, which is further enhanced when MSCs are primed in hypoxia. Furthermore, MSC-mediated Treg expansion does not require direct cell-cell contact. The expression of indolamine 2,3-dioxygenase, a mediator of MSC immunomodulation, increases when MSCs are primed in hypoxia, and inhibition of IDO significantly decreases the expansion of Tregs. Priming with inflammatory cytokines IFNγ and TNFα increases also expression of markers associated with MSC immunomodulatory function, but decreases MSC proliferation. The expression of IDO also increases when MSCs are primed with inflammatory cytokines. However, there is no increase in Treg expansion when MSCs are primed with IFNγ, suggesting an alternate mechanism for inflammatory-stimulated MSC immunomodulation. Overall, these results suggest that MSCs primed in hypoxia or inflammatory conditions are optimally primed for immunosuppressive function. These results provide a clearer picture of how to enhance MSC immunomodulation for clinical use.

Targeted Nrf2 activation therapy with RTA 408 enhances regenerative capacity of diabetic wounds

AIMS Though unmitigated oxidative stress in diabetic chronic non-healing wounds poses a major therapeutic challenge, currently, there are no effective pharmacological agents. We targeted the cytoprotective Nrf2/Keap1 pathway, which is dysfunctional in diabetic skin and the regenerative environment in the diabetic wound. We assessed the efficacy of a potent Nrf2-activator, RTA 408, a semi-synthetic oleanane triterpenoid, on accelerating diabetic wound healing. METHODS Using Leprdb/dbmice, we made 10 mm-diameter excisional humanized wounds in dorsal skin. We administered RTA 408 formulations daily, and used ANOVA for comparison of time to closure, in vivo real-time ROS, histology, molecular changes. RESULTS We found that RTA 408, specifically a 0.1% formulation, significantly reduced wound healing time and increased wound closure rate. While either systemic or topical administration of RTA 408 is effective, wound closure time with the latter was far superior. RTA 408-treated diabetic wounds upregulated Nrf2 and downstream antioxidant genes, and exhibited well-vascularized granulation tissue that aided in re-epithelialization. Reintroduction of redox mechanisms via RTA 408-induced Nrf2 resulted in reduction of the oxidative status of wounds, to coordinate successful wound closure. CONCLUSIONS This preclinical study shows that promoting Nrf2-mediated antioxidant activity in the localized regenerative milieu of a diabetic wound markedly improves the molecular and cellular composition of diabetic wound beds. RTA 408 treats and corrects the irregularity in redox balance mechanisms involving Nrf2, in an avenue not explored previously for treatment of diabetic wounds and tissue regeneration. Our study supports development of RTA 408 as a therapeutic modality for chronic diabetic wounds.

Abstract: Subcutaneous Only Brazilian Butt Lift

RESULTS: The Danger Zone concept, already published by the authors to avoid MAFE, can also be applied to prevent MIFE, because it not only compromises the inferior gluteal vein, which is one of the main concern to be damaged and allow fat into bloodstream (MAFE) but also includes the muscle area with highest density of vessels in gluteal region that could allow absorption of free oil without direct vessel wall rupture (MIFE).

Diabetes is not associated with increased rates of free flap failure: Analysis of outcomes in 6030 patients from the ACS-NSQIP database

Diabetes affects a significant proportion of the population in the United States. Microsurgical procedures are common in this patient population, and despite many conflicting reports in the literature, there are no large studies evaluating the direct association between diabetes and outcomes, specifically failure, following free flap reconstruction. In this study, we sought to determine the impact of diabetes on postoperative outcomes following free flap reconstruction using a national multi‐institutional database.

Ex vivo allotransplantation engineering: Delivery of mesenchymal stem cells prolongs rejection-free allograft survival

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.

Assessing the Value of a Multimedia-Based Aesthetic Curriculum in Plastic Surgery Residency: A Single-Center Pilot Study

Background Although global demand for cosmetic surgery continues to rise, plastic surgery residents feel that current models of aesthetic training are inadequate in preparing them for future practice. Digital learning resources offer promising educational possibilities, yet there are no formal studies investigating the integration of these technologies into the aesthetic curriculum. Objectives Here, we review the current state of aesthetic training for plastic surgery residents and present a pilot study investigating the value of a dedicated multimedia-based aesthetic curriculum at a single, large academic program. Methods Twenty plastic surgery residents participated in an 8-week curriculum consisting of weekly multimedia-based modules covering a specific aesthetic topic. Participants completed pre- and post-intervention surveys at 0 and 10 weeks, respectively. Surveys evaluated resident perspectives of the current state of aesthetic training, confidence in performing surgical and non-surgical aesthetic procedures, perceived efficacy of multimedia interventions for learning, and preferences for inclusion of such approaches in future curricula. Results 16.7% of participants planned on entering an aesthetic fellowship following residency. The mean number of months of dedicated cosmetic surgery rotations was 1.65 months. Resident confidence level in performing a particular aesthetic procedure significantly increased in 6/14 modules. More than 90% of residents were interested in incorporating the modules into residency. Conclusions Technology-based aesthetic training is critical for producing the finest future practitioners and leaders of this specialty. Here, we show that plastic surgery residents can benefit from a multimedia-based aesthetic curriculum, even if they do not plan on pursuing a career devoted to cosmetic surgery.

How many people work in your operating room? An assessment of factors associated with instrument recounts within plastic surgery

BACKGROUND Intraoperative instrument recounts are performed to avoid retained foreign surgical items. These additional counts, however, beget risks of their own, including prolonged operative times, exposure to radiation, and increased cost. Our study aimed to identify factors that increase the likelihood of instrument recounts during plastic surgery procedures, and use our findings to guide potential solutions for preventing unnecessary recounts across all surgical fields. STUDY DESIGN This is a retrospective review of all plastic surgical cases in the main operating setting at New York University Langone Medical Center (NYULMC) between March 2014 and February 2015. RESULTS Of 1285 plastic surgery cases, 35 (2.7%) reported a missing instrument necessitating a recount. Of all subspecialties within plastic surgery, only microsurgery conferred an increased risk of a recount event. We identified multiple factors that increased the odds of a recount event, including increased operative time, number of surgical sites, and intraoperative instrument handoffs. CONCLUSION Instrument recounts, although designed to prevent inadvertently retained surgical items, present inherent risks of their own. In a large retrospective review of plastic surgery cases at our medical center, we identified many factors that increased the likelihood of an instrument recount. On the basis of our findings and prior literature, we recommend limiting the number of staff handling instrument, the number of handoffs, and a heightened awareness by surgeons and perioperative staff of specific procedures and factors that increase the risk of a miscount event.