Enteric glial cell network function is required for epithelial barrier restitution following intestinal ischemic injury in the early postnatal period.

Ischemic damage to the intestinal epithelial barrier, such as in necrotizing enterocolitis or small intestinal volvulus, is associated with higher mortality rates in younger patients. We have recently reported a powerful pig model to investigate these age-dependent outcomes in which mucosal barrier restitution is strikingly absent in neonates but can be rescued by direct application of homogenized mucosa from older, juvenile pigs by a yet-undefined mechanism. Within the mucosa, a postnatally developing network of enteric glial cells (EGCs) is gaining recognition as a key regulator of the mucosal barrier. Therefore, we hypothesized that the developing EGC network may play an important role in coordinating intestinal barrier repair in neonates. Neonatal and juvenile jejunal mucosa recovering from surgically induced intestinal ischemia was visualized by scanning electron microscopy and the transcriptomic phenotypes were assessed by bulk RNA sequencing. EGC network density and glial activity were examined by Gene Set Enrichment Analysis, three-dimensional (3-D) volume imaging, and Western blot and its function in regulating epithelial restitution was assessed ex vivo in Ussing chamber using the glia-specific inhibitor fluoroacetate (FA), and in vitro by coculture assay. Here we refine and elaborate our translational model, confirming a neonatal phenotype characterized by a complete lack of coordinated reparative signaling in the mucosal microenvironment. Furthermore, we report important evidence that the subepithelial EGC network changes significantly over the early postnatal period and demonstrate that the proximity of a specific functional population of EGC to wounded intestinal epithelium contributes to intestinal barrier restitution following ischemic injury.NEW & NOTEWORTHY This study refines a powerful translational pig model, defining an age-dependent relationship between enteric glia and the intestinal epithelium during intestinal ischemic injury and confirming an important role for enteric glial cell (EGC) activity in driving mucosal barrier restitution. This study suggests that targeting the enteric glial network could lead to novel interventions to improve recovery from intestinal injury in neonatal patients.

Clot-Targeted Nanogels for Dual-Delivery of AntithrombinIII and Tissue Plasminogen Activator to Mitigate Disseminated Intravascular Coagulation Complications.

Disseminated intravascular coagulation (DIC) is a pathologic state that follows systemic injury and other diseases. Often a complication of sepsis or trauma, DIC causes coagulopathy associated with paradoxical thrombosis and hemorrhage. DIC upregulates the thrombotic pathways while simultaneously downregulating the fibrinolytic pathways that cause excessive fibrin deposition, microcirculatory thrombosis, multiorgan dysfunction, and consumptive coagulopathy with excessive bleeding. Given these opposing disease phenotypes, DIC management is challenging and includes treating the underlying disease and managing the coagulopathy. Currently, no therapies are approved for DIC. We have developed clot-targeted therapeutics that inhibit clot polymerization and activate clot fibrinolysis to manage DIC. We hypothesize that delivering both an anticoagulant and a fibrinolytic agent directly to clots will inhibit active clot polymerization while also breaking up pre-existing clots; therefore, reversing consumptive coagulopathy and restoring hemostatic balance. To test this hypothesis, we single- and dual-loaded fibrin-specific nanogels (FSNs) with antithrombinIII (ATIII) and/or tissue plasminogen activator (tPA) and evaluated their clot preventing and clot lysing abilities in vitro and in a rodent model of DIC. In vivo, single-loaded ATIII-FSNs decreased fibrin deposits in DIC organs and reduced blood loss when DIC rodents were injured. We also observed that the addition of tPA in dual-loaded ATIII-tPA-FSNs intensified the antithrombotic and fibrinolytic mechanisms, which proved advantageous for clot lysis and restoring platelet counts. However, the addition of tPA may have hindered wound healing capabilities when an injury was introduced. Our data supports the benefits of delivering both anticoagulants and fibrinolytic agents directly to clots to reduce the fibrin load and restore hemostatic balance in DIC.

Recent Advances in Blood Cell-Inspired and Clot Targeted Thrombolytic Therapies.

Myocardial infarction, stroke, and pulmonary embolism are all deadly conditions associated with excessive thrombus formation. Standard treatment for these conditions involves systemic delivery of thrombolytic agents to break up clots and restore blood flow; however, this treatment can impact the hemostatic balance in other parts of the vasculature, which can lead to excessive bleeding. To avoid this potential danger, targeted thrombolytic treatments that can successfully target thrombi and release an effective therapeutic load are necessary. Because activated platelets and fibrin make up a large proportion of clots, these two components provide ample opportunities for targeting. This review will highlight potential thrombus targeting mechanisms as well as recent advances in thrombolytic therapies which utilize blood-cells and clotting proteins to effectively target and lyse clots.