Publications by authors named "Jillian R Richter"

Background: Hemorrhage is the most common cause of potentially preventable death after injury. Balanced transfusion with red blood cells, plasma, and platelets (component therapy, CT) has been shown to reduce mortality, and is the standard of care. Low-Titer Group O Whole Blood (LTOWB) is an attractive alternative to CT, but existing evidence comprises observational studies, and a small single center pilot randomized controlled trial, which evaluated a type of whole blood that is no longer in use.

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Introduction : Trauma and hemorrhagic shock (T/HS) are associated with multiple organ injury. Antithrombin (AT) has anti-inflammatory and organ protective activity through its interaction with endothelial heparan sulfate containing a 3- O -sulfate modification. Our objective was to examine the effects of T/HS on 3- O -sulfated (3-OS) heparan sulfate expression and determine whether AT-heparan sulfate interactions are necessary for its anti-inflammatory properties.

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Introduction: Previous studies suggested that type O blood may be associated with increased mortality and/or thrombotic complications among trauma patients. The purpose of this analysis was to evaluate the relationship between endogenous blood type, mortality, and complications among patients receiving massive transfusions, using data from the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial.

Materials And Methods: This was a secondary analysis of the Pragmatic Randomized Optimal Platelet and Plasma Ratios trial that included patients with the reported blood type (A, AB, B, or O) data.

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Heparan sulfate (HS) in the vascular endothelial glycocalyx (eGC) is a critical regulator of blood vessel homeostasis. Trauma results in HS shedding from the eGC, but the impact of trauma on HS structural modifications that could influence mechanisms of vascular injury and repair has not been evaluated. Moreover, the effect of eGC HS shedding on endothelial cell (EC) homeostasis has not been fully elucidated.

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Introduction: Plasma levels of syndecan-1 (Sdc-1), a biomarker of endothelial glycocalyx (EG) damage, correlate with worse outcomes in trauma patients. However, EG injury is not well characterized in injured older adults (OA). The aims of this study were to characterize Sdc-1 shedding in OA trauma patients relative to younger adults (YA) and determine associations with putative regulators of EG sheddases.

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Introduction: Dysregulated inflammation and coagulation are underlying mechanisms driving organ injury after trauma and hemorrhagic shock. Heparan sulfates, cell surface glycosaminoglycans abundantly expressed on the endothelial surface, regulate a variety of cellular processes. Endothelial heparan sulfate containing a rare 3--sulfate modification on a glucosamine residue is anticoagulant and anti-inflammatory through high-affinity antithrombin binding and sequestering of circulating damage-associated molecular pattern molecules.

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The glycocalyx attached to the apical surface of vascular endothelial cells is a rich network of proteoglycans, glycosaminoglycans, and glycoproteins with instrumental roles in vascular homeostasis. Given their molecular complexity and ability to interact with the intra- and extracellular environment, heparan sulfate proteoglycans uniquely contribute to the glycocalyx's role in regulating endothelial permeability, mechanosignaling, and ligand recognition by cognate cell surface receptors. Much attention has recently been devoted to the enzymatic shedding of heparan sulfate proteoglycans from the endothelial glycocalyx and its impact on vascular function.

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Angiopoietin-2 (Ang-2) is a key mediator of vascular disease during sepsis, and elevated plasma levels of Ang-2 are associated with organ injury scores and poor clinical outcomes. We have previously observed that biomarkers of endothelial glycocalyx (EG) damage correlate with plasma Ang-2 levels, suggesting a potential mechanistic linkage between EG injury and Ang-2 expression during states of systemic inflammation. However, the cell signaling mechanisms regulating Ang-2 expression following EG damage are unknown.

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Objectives: Determine associations between biomarkers of endotheliopathy, 24-hour fibrinolysis phenotypes and clinical outcomes after trauma.

Background: The vascular endothelium is a critical regulator of hemostasis and organ function. The relationship between markers of endotheliopathy and fibrinolysis following trauma has not been evaluated.

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The vascular endothelium is the interface between circulating blood and end organs and thus has a critical role in preserving organ function. The endothelium is lined by a glycan-rich glycocalyx that uniquely contributes to endothelial function through its regulation of leukocyte and platelet interactions with the vessel wall, vascular permeability, coagulation, and vasoreactivity. Degradation of the endothelial glycocalyx can thus promote vascular dysfunction, inflammation propagation, and organ injury.

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Introduction: Acute traumatic coagulopathy (ATC) is an endogenous impairment in hemostasis that often contributes to early mortality after trauma. Endothelial glycocalyx damage is associated with trauma-induced coagulation abnormalities; however, the specific relationship between hyaluronan (HA), a key glycocalyx constituent, and ATC has not been evaluated.

Methods: We performed a secondary analysis of prospectively collected data from a recent study in which trauma patients (>18 years) admitted to our Level I trauma center with an ABC Score≥2 were enrolled.

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Objectives: Results from preclinical and adult sepsis studies suggest that the balance of circulating angiopoietin-1 and -2 levels, represented as angiopoietin-2/-1 ratios, plays a pivotal role in mediating vascular dysfunction and organ injury during sepsis. However, the relationship of plasma angiopoietins with organ injury and clinical outcomes in children with sepsis remains unknown. We sought to determine whether plasma angiopoietin-1 and -2 levels and angiopoietin-2/-1 ratios in the acute phase of sepsis correlated with measures of organ injury and clinical outcomes in children with sepsis.

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Both heparanase and syndecan-1 are known to be present and active in disease pathobiology. An important feature of syndecan-1 related to its role in pathologies is that it can be shed from the surface of cells as an intact ectodomain composed of the extracellular core protein and attached heparan sulfate and chondroitin sulfate chains. Shed syndecan-1 remains functional and impacts cell behavior both locally and distally from its cell of origin.

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Traumatic injury and hemorrhagic shock result in endothelial cell activation and vascular dysfunction that, if not corrected, can propagate multiorgan failure. Angiopoietin-1 and angiopoietin-2 are important regulators of endothelial cell function, and the ratio of plasma angiopoietin-2-to-1 is a useful indicator of overall vascular health. We therefore characterized plasma angiopoietin-2/-1 ratios over time after trauma in adults in an effort to gain insight into the pathophysiology that may drive post-traumatic vasculopathy and organ injury.

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Background: A major obstacle to using recombinant adenoviral vectors in gene therapy is the natural ability of human adenovirus to activate the classical and alternate complement pathways. These innate immune responses contribute to hepatic adenoviral uptake following systemic delivery and enhance the humoral immune responses associated with adenoviral infection.

Methods: A recombinant Ad5 vector was genetically modified to display a peptide sequence ("rH17d'"), a known inhibitor of the classical complement pathway.

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Article Synopsis
  • Elevated plasma levels of angiopoietin-1 (Agpt-1) and angiopoietin-2 (Agpt-2) are found in pediatric trauma patients, with Agpt-2 levels significantly higher than in controls after 24 hours.
  • A notable increase in the Agpt-2:Agpt-1 ratio in trauma patients is observed, indicating a potential link to adverse clinical outcomes.
  • The study suggests a connection between elevated Agpt-2 and endothelial glycocalyx damage, as indicated by higher levels of syndecan-1 (Syn-1), warranting further research to explore these relationships.
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Background: Trauma is the leading cause of death and disability in patients aged 1-46 y. Severely injured patients experience considerable blood loss and hemorrhagic shock requiring treatment with massive transfusion of red blood cells (RBCs). Preclinical and retrospective human studies in trauma patients have suggested that poorer therapeutic efficacy, increased severity of organ injury, and increased bacterial infection are associated with transfusion of large volumes of stored RBCs, although the mechanisms are not fully understood.

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Background: Leukoreduction prior to packed red blood cell (pRBC) storage is not a universally accepted practice. Our laboratory has previously shown that microvesicles (MVs) accumulate in pRBC units during storage and play an important role in lung injury after resuscitation. Currently, the effect of leukoreduction on MV formation in stored pRBC units is unknown.

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The use of in vitro, engineered surrogates in the field of cancer research is of interest for studies involving mechanisms of growth and metastasis, and response to therapeutic intervention. While biomimetic surrogates better model human disease, their complex composition and dimensionality make them challenging to evaluate in a real-time manner. This feature has hindered the broad implementation of these models, particularly in drug discovery.

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Resuscitation of patients after hemorrhage often results in pulmonary inflammation and places them at risk for the development of acute respiratory distress syndrome. Our previous data indicate that macrophage-derived chemokine (MDC/CCL22) is elevated after resuscitation, but its direct role in this inflammatory response is unknown. Macrophage-derived chemokine signaling through the C-C chemokine receptor type 4 (CCR4) is implicated in other pulmonary proinflammatory conditions, leading us to hypothesize that MDC may also play a role in the pathogenesis of lung inflammation following hemorrhage and resuscitation.

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Driven by new discoveries in stem-cell biology and regenerative medicine, there is broad interest in biomaterials that go beyond basic interactions with cells and tissues to actively direct and sustain cellular behavior. Keratin biomaterials have the potential to achieve these goals but have been inadequately described in terms of composition, structure, and cell-instructive characteristics. In this manuscript we describe and characterize a keratin-based biomaterial, demonstrate self-assembly of cross-linked hydrogels, investigate a cell-specific interaction that is dependent on the hydrogel structure and mediated by specific biomaterial-receptor interactions, and show one potential medical application that relies on receptor binding - the ability to achieve hemostasis in a lethal liver injury model.

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Background: Transfusion of stored blood is associated with increased complications. Microparticles (MPs) are small vesicles released from RBCs that can induce cellular dysfunction, but the role of RBC-derived MPs in resuscitation from hemorrhagic shock is unknown. In the current study, we examined the effects of RBC-derived MPs on the host response to hemorrhage and resuscitation.

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The structure-property relationships of kerateine materials were studied by separating crude hair extracts into two protein sub-fractions, referred to as α- and γ-kerateines, followed by their de novo recombination into meta-kerateine hydrogels, sponges and films. The kerateine fractions were characterized using electrophoresis and mass spectrometry, which revealed that the α-fraction contained complexes of type I and type II keratins and that the γ-fraction was primarily protein fragments of the α-fraction along with three proteins of the KAP-1 family. Meta-kerateine materials with increased amounts of γ-kerateines showed diminished physical, mechanical and biological characteristics.

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