About

Ellie Rahbar is associated with the Texas A&M College of Veterinary Medicine & Biomedical Sciences (VMBS), which is ranked as the No. 3 veterinary college in the United States and is recognized for its research and academic programs. The college emphasizes collaborations that translate discoveries into proactive solutions for animal, human, and environmental health, adopting a 'One Health' approach that recognizes the complex interactions between these domains. While specific details about Ellie Rahbar's research focus, background, or key contributions are not provided in the page text, her association with VMBS suggests involvement in a leading institution dedicated to innovative research, veterinary education, and outreach efforts.

Research topics

• Chemistry
• Biology
• Computer Science
• Chromatography
• Biochemistry
• Medicine
• Computational biology
• Electronic engineering
• Genetics
• Anatomy
• Pathology
• Materials science
• Cell biology
• Molecular biology
• Nanotechnology
• Biophysics
• Biological system
• Immunology

Selected publications

• Multiomic changes posthypovolemia in a lower body negative pressure model: unlocking new mechanisms or adding to the complexity?

  Physiological Genomics · 2026-05-06

  articleOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Calibration of a Closed-loop Model of Porcine Aortic Hemodynamics during Hemorrhage

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-02-02

  articleOpen access

  Uncontrolled hemorrhage remains a leading cause of traumatic death, driven by rapid physiological deterioration that is often difficult to detect during the compensated phase. While large-animal models provide critical insights into these dynamics, they are resource-intensive, motivating the need for efficient computational frameworks that can mechanistically interpret cardiovascular responses. We developed and calibrated a closed-loop zero-dimensional (0D) lumped-parameter model (LPM) using hemodynamic data from 43 anesthetized swine subjected to controlled hemorrhage (10%, 20%, or 30% of total blood volume). The computational framework, incorporates a dynamic heart model with a custom time-varying elastance function, a multi-compartment aorta, and distal Windkessel models representing vascular beds. The model was calibrated at discrete time 'snapshots' throughout the 30-minute hemorrhage protocol to reproduce group-averaged experimental waveforms for aortic flow, regional organ flows, and systemic pressures. The calibrated model successfully reproduced experimental hemodynamic targets and waveform morphology across all hemorrhage severities. Analysis of the calibrated parameters revealed distinct physiological mechanisms driving hemodynamic adaptation during hemorrhage: a preferential increase in renal resistance compared to carotid resistance, indicating flow redistribution to vital organs, and a progressive mobilization of venous unstressed volume to sustain cardiac filling. Furthermore, the model captured the distinct shift toward preload limitation state for 30% hemorrhage group. This study establishes a physiologically interpretable in-silico framework capable of predicting both global and regional hemodynamic responses to acute blood loss, providing a validated foundation for future applications in trauma care and resuscitation modeling.

  PublisherOA PDFDOI

• A translational porcine model to assess the graded impact of hemorrhage and aortic occlusion on cardiovascular hemodynamics and renal perfusion

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-02-09

  articleOpen accessSenior authorCorresponding

  Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is a lifesaving intervention used to manage non-compressible torso hemorrhage by temporarily occluding the aorta to minimize blood loss and preserve perfusion to vital organs. Partial REBOA (p-REBOA) has been proposed to mitigate ischemic injury associated with full-REBOA (f-REBOA). However, implementation of p-REBOA clinically has been challenging due to our limited understanding of the acute hemodynamics with p-REBOA particularly in relation to cardiac, carotid, and renal perfusion. In this study we developed and utilized a novel porcine model to continuously measure cardiac, carotid, renal and systemic hemodynamic responses to varying degrees of hemorrhagic shock and aortic occlusion. Yorkshire pigs (N=54) underwent instrumentation for continuous hemodynamic monitoring and hemorrhage was induced for 30 minutes to achieve 10%, 20%, or 30% blood volume loss (n=18/group), followed by randomized treatments of either no occlusion, p-REBOA, or f-REBOA occlusion strategies (n=6/group) for 30 minutes. After occlusion, shed blood was re-transfused over 15 minutes, and REBOA balloons were deflated and removed. This was followed by a 3-hour automated resuscitation and critical care period. Renal and carotid perfusion decreased progressively with hemorrhage severity. Interestingly, 30 minutes of f-REBOA resulted in significant ischemia-reperfusion injury where renal perfusion was profoundly suppressed to 40% of baseline renal flow. On the other hand, p-REBOA yielded superior renal perfusion, while maintaining cardiac function and carotid perfusion. p-REBOA also required less fluid and vasopressors. This translational pig model offers new opportunities to assess acute cardiovascular hemodynamics during interventions for the management of hemorrhagic shock.

  PublisherOA PDFDOI

• Hemadyne: accordion-inspired perfusion for microphysiological systems

  Nature Communications · 2026-05-25

  articleOpen access
  PublisherDOI

• Partial Resuscitative Endovascular Balloon Occlusion of the Aorta Versus Intermittent Resuscitative Endovascular Balloon Occlusion of the Aorta in Noncompressible Torso Hemorrhage With Concomitant Traumatic Brain Injury

  Military Medicine · 2025-06-04 · 1 citations

  articleOpen access

  INTRODUCTION: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) temporizes noncompressible torso hemorrhage (NCTH) and provides hemodynamic support, yet is limited by ischemic effects. Intermittent REBOA (iREBOA) and partial REBOA (pREBOA) strategies aim to mitigate these effects. iREBOA alternates between distal flow restoration and full aortic occlusion. pREBOA provides hemodynamic support with attenuated distal flow by dynamically adjusting balloon volume. Hemodynamic profiles differ between these strategies, with an uncertain impact on concomitant injuries like traumatic brain injury (TBI). We hypothesized that pREBOA would demonstrate more consistent cerebral hemodynamics in a porcine model of hemorrhage and TBI. MATERIALS AND METHODS: Sixteen swine underwent standardized TBI, via cortical impactor, and liver transection, followed by 10 minutes of complete REBOA. Swine were then randomized to 80 minutes of automated iREBOA or pREBOA support. Following damage control surgery and whole blood transfusion, 90 minutes of automated closed-loop critical care was implemented. Hemodynamic parameters and ischemia-related laboratory values were recorded. Hypotension was defined as mean arterial pressure (MAP) < 60 mmHg, and hypertension as MAP > 70 mmHg. RESULTS: Carotid flow fluctuated less in pREBOA vs iREBOA at time intervals 0-10 minutes (P = .038), 10-20 minutes (P = .036), 20-30 minutes (P = .001), and 40-50 minutes (P = .04). Cerebral perfusion pressure (CPP) varied more in iREBOA than pREBOA at 20-30 minutes and 30-40 minutes (P = .0007 and 0.048). There were no statistically significant differences in time spent in hypotension and hypertension for iREBOA and pREBOA (45.26% vs 17.22%, P = .27; 38.31% vs 49.19%, P = .56). CONCLUSIONS: Partial REBOA with an automated system demonstrated more consistent CPP and carotid flow while maintaining proximal MAP. Dynamic control systems for NCTH are possible, and automation of pREBOA may balance competing risks of distal ischemia and proximal homeostasis in multi-injured trauma patients with TBI.

  PublisherOA PDFDOI

• Comparison of the capillary and venous blood plasma lipidomes: validation of self-collected blood for plasma lipidomics

  Journal of Lipid Research · 2025-02-12 · 8 citations

  articleOpen access

  Venipuncture of the upper extremities is commonly used to collect blood for plasma lipidomics. However, self-administered blood collection devices such as the Tasso+™ system for capillary blood sampling and plasma separation are convenient and enable frequent sampling without a clinical blood draw. The purpose of this study is to validate Tasso+ sampling for plasma lipidomics by comparing the venous blood and Tasso+-sampled capillary blood plasma lipidomes. Lipids are proven or putative biomarkers of human health and disease and indicators of nutritional and toxicological status. Because exchange of blood components including lipids occurs in capillaries, the capillary and venous blood lipidomes might be different, which could confound use of Tasso+-sampled blood as a surrogate for venous blood plasma. Here we compared the lipidomes of Tasso+-drawn capillary blood plasma and venous blood plasma in 10 male subjects using high-resolution mass spectrometry-based lipidomics. While there was substantial interindividual variability between lipidomes, comprehensive statistical approaches with cross-validation and multiple testing adjustments showed no difference (adjusted P-value > 0.05) in lipid composition of the paired blood samples. A linear regression model with Spearman correlation analysis also showed a significant-to-near-perfect level (r = 0.95-0.99) of concordance between the samples. Aside from monoacylglycerols and cardiolipins, every class of lipid was strongly correlated (r = 0.9-0.99) between paired venous and capillary blood plasma. In summary, the capillary and venous blood plasma lipidomes are essentially identical making self-administered collection of capillary blood a viable approach for clinical blood plasma lipidomics.

  PublisherOA PDFDOI

• INVESTIGATING THE RELATIONSHIP BETWEEN BLEEDING, CLOTTING, AND COAGULOPATHY DURING AUTOMATED PARTIAL REBOA STRATEGIES IN A HIGHLY LETHAL PORCINE HEMORRHAGE MODEL

  Shock · 2024-06-11 · 2 citations

  articleOpen accessSenior authorCorresponding

  ABSTRACT: Background: Death due to hemorrhagic shock, particularly, noncompressible truncal hemorrhage, remains one of the leading causes of potentially preventable deaths. Automated partial and intermittent resuscitative endovascular balloon occlusion of the aorta (i.e., pREBOA and iREBOA, respectively) are lifesaving endovascular strategies aimed to achieve quick hemostatic control while mitigating distal ischemia. In iREBOA, the balloon is titrated from full occlusion to no occlusion intermittently, whereas in pREBOA, a partial occlusion is maintained. Therefore, these two interventions impose different hemodynamic conditions, which may impact coagulation and the endothelial glycocalyx layer. In this study, we aimed to characterize the clotting kinetics and coagulopathy associated with iREBOA and pREBOA, using thromboelastography (TEG). We hypothesized that iREBOA would be associated with a more hypercoagulopathic response compared with pREBOA due to more oscillatory flow. Methods: Yorkshire swine (n = 8/group) were subjected to an uncontrolled hemorrhage by liver transection, followed by 90 min of automated pREBOA, iREBOA, or no balloon support (control). Hemodynamic parameters were continuously recorded, and blood samples were serially collected during the experiment (i.e., eight key time points: baseline (BL), T0, T10, T30, T60, T90, T120, T210 min). Citrated kaolin heparinase assays were run on a TEG 5000 (Haemonetics, Niles, IL). General linear mixed models were employed to compare differences in TEG parameters between groups and over time using STATA (v17; College Station, TX), while adjusting for sex and weight. Results: As expected, iREBOA was associated with more oscillations in proximal pressure (and greater magnitudes of peak pressure) because of the intermittent periods of full aortic occlusion and complete balloon deflation, compared to pREBOA. Despite these differences in acute hemodynamics, there were no significant differences in any of the TEG parameters between the iREBOA and pREBOA groups. However, animals in both groups experienced a significant reduction in clotting times (R time: P < 0.001; K time: P < 0.001) and clot strength (MA: P = 0.01; G: P = 0.02) over the duration of the experiment. Conclusions: Despite observing acute differences in peak proximal pressures between the iREBOA and pREBOA groups, we did not observe any significant differences in TEG parameters between iREBOA and pREBOA. The changes in TEG profiles were significant over time, indicating that a severe hemorrhage followed by both pREBOA and iREBOA can result in faster clotting reaction times (i.e., R times). Nevertheless, when considering the significant reduction in transfusion requirements and more stable hemodynamic response in the pREBOA group, there may be some evidence favoring pREBOA usage over iREBOA.

  PublisherOA PDFDOI

• High‐fidelity and iterative affinity extraction of hyaluronan

  Proteoglycan Research · 2024-10-01 · 3 citations

  articleOpen access

  The glycosaminoglycan hyaluronan (HA) serves a variety of crucial physiological functions in vertebrates. Synthesized at the plasma membrane and secreted into the extracellular environment, HA polymers span a wide range of molecular weights (MW) that define their activity through a notable size-function relationship. Analytical technologies for determining HA MW distributions typically require selective extraction from complex biofluids or tissues. A common method for achieving this is immunoprecipitation-like pull-down using specific HA-binding proteins bound to magnetic beads. Here, we present a systematic investigation of experimental variables involved in this process, leading to an affinity extraction protocol that enables iterative bead reuse and reagent lifetime maximization, thereby enhancing the efficiency of the HA extraction process. Our methods provide a framework for general optimization of immunoprecipitation in other contexts with heterogenous analyte sizes.

  PublisherOA PDFDOI

• Targeted Analysis of the Size Distribution of Heavy Chain-Modified Hyaluronan with Solid-State Nanopores

  Analytical Chemistry · 2024-01-12 · 11 citations

  articleOpen access

  The glycosaminoglycan hyaluronan (HA) plays important roles in diverse physiological functions where the distribution of its molecular weight (MW) can influence its behavior and is known to change in response to disease conditions. During inflammation, HA undergoes a covalent modification in which heavy chain subunits of the inter-alpha-inhibitor family of proteins are transferred to its structure, forming heavy chain-HA (HC•HA) complexes. While limited assessments of HC•HA have been performed previously, determining the size distribution of its HA component remains a challenge. Here, we describe a selective method for extracting HC•HA from mixtures that yields material amenable to MW analysis with a solid-state nanopore sensor. After demonstrating the approach in vitro, we validate extraction of HC•HA from osteoarthritic human synovial fluid as a model complex biological matrix. Finally, we apply our technique to pathophysiology by measuring the size distributions of HC•HA and total HA in an equine model of synovitis.

  PublisherOA PDFDOI

• MAN VERSUS MACHINE: PROVIDER DIRECTED VERSUS PRECISION AUTOMATED CRITICAL CARE MANAGEMENT IN A PORCINE MODEL OF DISTRIBUTIVE SHOCK

  Shock · 2024-03-25

  articleOpen access

  ABSTRACT: Background: Critical care management of shock is a labor-intensive process. Precision Automated Critical Care Management (PACC-MAN) is an automated closed-loop system incorporating physiologic and hemodynamic inputs to deliver interventions while avoiding excessive fluid or vasopressor administration. To understand PACC-MAN efficacy, we compared PACC-MAN to provider-directed management (PDM). We hypothesized that PACC-MAN would achieve equivalent resuscitation outcomes to PDM while maintaining normotension with lower fluid and vasopressor requirements. Methods : Twelve swine underwent 30% controlled hemorrhage over 30 min, followed by 45 min of aortic occlusion to generate a vasoplegic shock state, transfusion to euvolemia, and randomization to PACC-MAN or PDM for 4.25 h. Primary outcomes were total crystalloid volume, vasopressor administration, total time spent at hypotension (mean arterial blood pressure <60 mm Hg), and total number of interventions. Results : Weight-based fluid volumes were similar between PACC-MAN and PDM; median and IQR are reported (73.1 mL/kg [59.0-78.7] vs. 87.1 mL/kg [79.4-91.8], P = 0.07). There was no statistical difference in cumulative norepinephrine (PACC-MAN: 33.4 μg/kg [27.1-44.6] vs. PDM: 7.5 [3.3-24.2] μg/kg, P = 0.09). The median percentage of time spent at hypotension was equivalent (PACC-MAN: 6.2% [3.6-7.4] and PDM: 3.1% [1.3-6.6], P = 0.23). Urine outputs were similar between PACC-MAN and PDM (14.0 mL/kg vs. 21.5 mL/kg, P = 0.13). Conclusion : Automated resuscitation achieves equivalent resuscitation outcomes to direct human intervention in this shock model. This study provides the first translational experience with the PACC-MAN system versus PDM.

  PublisherDOI

Recent grants

• An Integrated Investigation of the Interaction Between PUFAs and Genetic Variants in Trauma and Critical Care

  NIH · $690k · 2017–2022

Frequent coauthors

• John B. Holcomb

  University of Alabama at Birmingham

  45 shared

• Bryan A. Cotton

  The University of Texas Health Science Center at Houston

  42 shared

• Erin E. Fox

  The University of Texas Health Science Center at Houston

  22 shared

• Charles E. Wade

  The University of Texas Health Science Center at Houston

  21 shared

• Kenji Inaba

  University of Southern California

  21 shared

• Antonio C. Renaldo

  Wake Forest University

  20 shared

• Mitchell J. Cohen

  University of Colorado Denver

  20 shared

• Deborah M. Stein

  University of Maryland, Baltimore

  17 shared