Development of Optimized Tissue-Factor-Targeted Peptide Amphiphile Nanofibers to Slow Noncompressible Torso Hemorrhage.

Noncompressible torso hemorrhage accounts for a significant portion of preventable trauma deaths. We report here on the development of injectable, targeted supramolecular nanotherapeutics based on peptide amphiphile (PA) molecules that are designed to target tissue factor (TF) and, therefore, selectively localize to sites of injury to slow hemorrhage. Eight TF-targeting sequences were identified, synthesized into PA molecules, coassembled with nontargeted backbone PA at various weight percentages, and characterized via circular dichroism spectroscopy, transmission electron microscopy, and X-ray scattering. Following intravenous injection in a rat liver hemorrhage model, two of these PA nanofiber coassemblies exhibited the most specific localization to the site of injury compared to controls (p < 0.05), as quantified using immunofluorescence imaging of injured liver and uninjured organs. To determine if the nanofibers were targeting TF in vivo, a mouse saphenous vein laser injury model was performed and showed that TF-targeted nanofibers colocalized with fibrin, demonstrating increased levels of nanofiber at TF-rich sites. Thromboelastograms obtained using samples of heparinized rat whole blood containing TF demonstrated that no clots were formed in the absence of TF-targeted nanofibers. Lastly, both PA nanofiber coassemblies decreased blood loss in comparison to sham and backbone nanofiber controls by 35-59% (p < 0.05). These data demonstrate an optimal TF-targeted nanofiber that localizes selectively to sites of injury and TF exposure, and, interestingly, reduces blood loss. This research represents a promising initial phase in the development of a TF-targeted injectable therapeutic to reduce preventable deaths from hemorrhage.

Emerging Therapies for Prehospital Control of Hemorrhage.

BACKGROUND: The aim of this review was to describe emerging therapies that could serve as a prehospital intervention to slow or stop noncompressible torso hemorrhage in the civilian and military settings. Hemorrhage accounts for 90% of potentially survivable military deaths and 30%-40% of trauma deaths. There is a great need to develop novel therapies to slow or stop noncompressible torso hemorrhage at the scene of the injury. METHODS: A comprehensive literature search was performed using PubMed (1966 to present) for therapies not approved by the Food and Drug Administration for noncompressible torso hemorrhage in the prehospital setting. Therapies were divided into compressive versus intravascular injectable therapies. Ease of administration, skill required to use the therapy, safety profile, stability, shelf-life, mortality benefit, and efficacy were reviewed. RESULTS: Multiple potential therapies for noncompressible torso hemorrhage are currently under active investigation. These include (1) tamponade therapies, such as gas insufflation and polyurethane foam injection; (2) freeze-dried blood products and alternatives such as lyophilized platelets; (3) nanoscale injectable therapies such as polyethylene glycol nanospheres, polyethylenimine nanoparticles, SynthoPlate, and tissue factor-targeted nanofibers; and (4) other injectable therapies such as polySTAT and adenosine, lidocaine, and magnesium. Although each of these therapies shows great promise at slowing or stopping hemorrhage in animal models of noncompressible hemorrhage, further research is needed to ensure safety and efficacy in humans. CONCLUSIONS: Multiple novel therapies are currently under active investigation to slow or stop noncompressible torso hemorrhage in the prehospital setting and show promising results.

Fellowship or Family? A Comparison of Residency Leave Policies With the Family and Medical Leave Act.

BACKGROUND: In 1993, the Family and Medical Leave Act (FMLA) mandated 12 weeks of unpaid, job-protected leave. The current impact of taking 12 weeks of leave during residency has not been evaluated. METHODS: We examined the 2018 Accreditation Council for Graduate Medical Education (n = 24) specialty leave policies to determine the impact of 6- and 12-week leave on residency training, board eligibility, and fellowship training. We compared our findings with a 2006 study. RESULTS: In 2018, five (21%) specialties had policy language regarding parental leave during residency, and four (16%) had language regarding medical leave. Median leave allowed was 4 weeks (IQR 4-6). Six specialties (25%) decreased the number of weeks allowed for leave from 2006 to 2018. In 2006, a 6-week leave would cause a 1-year delay in board eligibility in six specialties; in 2018, it would not cause delayed board eligibility in any specialty. In 2018, a 12-week (FMLA) leave would extend training by a median of 6 weeks (mean 4.1, range 0-8), would delay board eligibility by 6-12 months in three programs (mean 2.25, range 0-12), and would delay fellowship training by at least 1 year in 17 specialties (71%). The impact of a 12-week leave was similar between medical and surgical specialties. CONCLUSIONS: While leave policies have improved since 2006, most specialties allow for 6 weeks of leave, less than half of what is mandated by the FMLA. Moreover, a 12-week, FMLA-mandated leave would cause significant delays in board certification and entry into fellowship for most residency programs.