William J Federspiel

University of Pittsburgh, Pittsburgh, Pennsylvania, United States

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Publications (133)308.8 Total impact

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    ABSTRACT: Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake - Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana® polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A=497ε-103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to -3.5% of our prior correlation over the tested porosity range.
    No preview · Article · Jan 2016 · ASAIO Journal
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    ABSTRACT: Neutrophils play a central role in eliminating bacterial pathogens, but may also contribute to end-organ damage in sepsis. Interleukin-8 (IL-8), a key modulator of neutrophil function, signals through neutrophil specific surface receptors CXCR-1 and CXCR-2. In this study a mechanistic computational model was used to evaluate and deploy an extracorporeal sepsis treatment which modulates CXCR-1/2 levels. First, a simplified mechanistic computational model of IL-8 mediated activation of CXCR-1/2 receptors was developed, containing 16 ODEs and 43 parameters. Receptor level dynamics and systemic parameters were coupled with multiple neutrophil phenotypes to generate dynamic populations of activated neutrophils which reduce pathogen load, and/or primed neutrophils which cause adverse tissue damage when misdirected. The mathematical model was calibrated using experimental data from baboons administered a two-hour infusion of E coli and followed for a maximum of 28 days. Ensembles of parameters were generated using a Bayesian parallel tempering approach to produce model fits that could recreate experimental outcomes. Stepwise logistic regression identified seven model parameters as key determinants of mortality. Sensitivity analysis showed that parameters controlling the level of killer cell neutrophils affected the overall systemic damage of individuals. To evaluate rescue strategies and provide probabilistic predictions of their impact on mortality, time of onset, duration, and capture efficacy of an extracorporeal device that modulated neutrophil phenotype were explored. Our findings suggest that interventions aiming to modulate phenotypic composition are time sensitive. When introduced between 3–6 hours of infection for a 72 hour duration, the survivor population increased from 31% to 40–80%. Treatment efficacy quickly diminishes if not introduced within 15 hours of infection. Significant harm is possible with treatment durations ranging from 5–24 hours, which may reduce survival to 13%. In severe sepsis, an extracorporeal treatment which modulates CXCR-1/2 levels has therapeutic potential, but also potential for harm. Further development of the computational model will help guide optimal device development and determine which patient populations should be targeted by treatment.
    Full-text · Article · Oct 2015 · PLoS Computational Biology
  • Shalv Madhani · William J. Federspiel

    No preview · Article · Sep 2015 · Journal of Membrane Science
  • D T Arazawa · J D Kimmel · M C Finn · W J Federspiel
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    ABSTRACT: Unlabelled: The use of extracorporeal carbon dioxide removal (ECCO2R) is well established as a therapy for patients suffering from acute respiratory failure. Development of next generation low blood flow (<500mL/min) ECCO2R devices necessitates more efficient gas exchange devices. Since over 90% of blood CO2 is transported as bicarbonate (HCO3(-)), we previously reported development of a carbonic anhydrase (CA) immobilized bioactive hollow fiber membrane (HFM) which significantly accelerates CO2 removal from blood in model gas exchange devices by converting bicarbonate to CO2 directly at the HFM surface. This present study tested the hypothesis that dilute sulfur dioxide (SO2) in oxygen sweep gas could further increase CO2 removal by creating an acidic microenvironment within the diffusional boundary layer adjacent to the HFM surface, facilitating dehydration of bicarbonate to CO2. CA was covalently immobilized onto poly (methyl pentene) (PMP) HFMs through glutaraldehyde activated chitosan spacers, potted in model gas exchange devices (0.0151m(2)) and tested for CO2 removal rate with oxygen (O2) sweep gas and a 2.2% SO2 in oxygen sweep gas mixture. Using pure O2 sweep gas, CA-PMP increased CO2 removal by 31% (258mL/min/m(2)) compared to PMP (197mL/min/m(2)) (P<0.05). Using 2.2% SO2 acidic sweep gas increased PMP CO2 removal by 17% (230mL/min/m(2)) compared to pure oxygen sweep gas control (P<0.05); device outlet blood pH was 7.38 units. When employing both CA-PMP and 2.2% SO2 sweep gas, CO2 removal increased by 109% (411mL/min/m(2)) (P<0.05); device outlet blood pH was 7.35 units. Dilute acidic sweep gas increases CO2 removal, and when used in combination with bioactive CA-HFMs has a synergistic effect to more than double CO2 removal while maintaining physiologic pH. Through these technologies the next generation of intravascular and paracorporeal respiratory assist devices can remove more CO2 with smaller blood contacting surface areas. Statement of significance: A clinical need exists for more efficient respiratory assist devices which utilize low blood flow rates (<500mL/min) to regulate blood CO2 in patients suffering from acute lung failure. Literature has demonstrated approaches to chemically increase hollow fiber membrane (HFM) CO2 removal efficiency by shifting equilibrium from bicarbonate to gaseous CO2, through either a bioactive carbonic anhydrase enzyme coating or bulk blood acidification with lactic acid. In this study we demonstrate a novel approach to local blood acidification using an acidified sweep gas in combination with a bioactive coating to more than double CO2 removal efficiency of HFM devices. To our knowledge, this is the first report assessing an acidic sweep gas to increase CO2 removal from blood using HFM devices.
    No preview · Article · Jul 2015 · Acta biomaterialia
  • D T Arazawa · J D Kimmel · W J Federspiel
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    ABSTRACT: Artificial lung devices comprised of hollow fiber membranes (HFMs) coated with the enzyme carbonic anhydrase (CA), accelerate removal of carbon dioxide (CO2) from blood for the treatment of acute respiratory failure. While previous work demonstrated CA coatings increase HFM CO2 removal by 115 % in phosphate buffered saline (PBS), testing in blood revealed a 36 % increase compared to unmodified HFMs. In this work, we sought to characterize the CO2 mass transport processes within these biocatalytic devices which impede CA coating efficacy and develop approaches towards improving bioactive HFM efficiency. Aminated HFMs were sequentially reacted with glutaraldehyde (GA), chitosan, GA and afterwards incubated with a CA solution, covalently linking CA to the surface. Bioactive CA-HFMs were potted in model gas exchange devices (0.0119 m(2)) and tested for esterase activity and CO2 removal under various flow rates with PBS, whole blood, and solutions containing individual blood components (plasma albumin, red blood cells or free carbonic anhydrase). Results demonstrated that increasing the immobilized enzyme activity did not significantly impact CO2 removal rate, as the diffusional resistance from the liquid boundary layer is the primary impediment to CO2 transport by both unmodified and bioactive HFMs under clinically relevant conditions. Furthermore, endogenous CA within red blood cells competes with HFM immobilized CA to increase CO2 removal. Based on our findings, we propose a bicarbonate/CO2 disequilibrium hypothesis to describe performance of CA-modified devices in both buffer and blood. Improvement in CO2 removal rates using CA-modified devices in blood may be realized by maximizing bicarbonate/CO2 disequilibrium at the fiber surface via strategies such as blood acidification and active mixing within the device.
    No preview · Article · Jun 2015 · Journal of Materials Science Materials in Medicine
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    Matthew E Cove · William J Federspiel

    Preview · Article · Apr 2015 · Critical Care
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    ABSTRACT: Hemoadsorption may improve outcomes for sepsis by removing circulating cytokines. We tested a new sorbent used for hemoadsorption. CTR sorbent beads were filled into columns of three sizes: CTR0.5 (0.5 ml), CTR1 (1.0 ml) and CTR2 (2.0 ml) and tested using IL-6 capture in vitro. Next, rats were subjected to cecal ligation and puncture and randomly assigned to hemoadsorption with CTR0.5, CTR1, CTR2 or sham treatment. Plasma biomarkers were measured. In vitro, IL-6 removal was accelerated with increasing bead mass. In vivo, TNF, IL-6, IL-10, high mobility group box1, and cystatin C were significantly lower 24 h after CTR2 treatment. Seven-day survival rate was 50, 64, 63, and 73% for the sham, CTR0.5, CTR1, CTR2, respectively. CTR appeared to have a favorable effect on kidney function despite no immediate effects on cytokine removal. However, CTR2 beads did result in a late decrease of cytokines. © 2015 S. Karger AG, Basel.
    No preview · Article · Apr 2015 · Blood Purification
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    ABSTRACT: Respiratory assist devices seek optimized performance in terms of gas transfer efficiency and thromboresistance to minimize device size and reduce complications associated with inadequate blood biocompatibility. Gas exchange with blood occurs at the surface of the hollow fiber membranes (HFMs) used in these devices. In this study, three zwitterionic macromolecules were attached to HFM surfaces to putatively improve thromboresistance: 1) carboxyl-functionalized zwitterionic phosphorylcholine (PC) and 2)sulfobetaine (SB) macromolecules (mPC or mSB-COOH) prepared by a simple thiol-ene radical polymerization, and 3) a low molecular weight (LMW) sulfobetaine (SB)-co-methacrylic acid (MA) block copolymer (SBMAb-COOH) prepared by reversible addition fragmentation chain transfer (RAFT) polymerization. Each macromolecule type was covalently immobilized on an aminated commercial HFM (Celg-A) by a condensation reaction and HFM surface composition changes were analyzed by X-ray photoelectron spectroscopy. Thrombotic deposition on the HFMs was investigated after contact with ovine blood in vitro. CO2 removal by the HFMs also evaluated using a model respiratory assist device. The HFMs conjugated with zwitterionic macromolecules (Celg-mPC, Celg-mSB or Celg-SBMAb) showed expected increases in phosphorus or sulfur surface content. Celg-mPC and Celg-SBMAb experienced significantly lower platelet deposition than unmodified (Celg-A, >95% reduction) and heparin coated (>88% reduction) control HFMs. Lesser reductions were seen with Celg-mSB. The CO2 removal rate for Celg-SBMAb HFMs remained comparable to Celg-A. In contrast CO2 removal for heparin coated HFMs was significantly reduced. The results demonstrate a promising approach to modify HFMs using zwitterionic macromolecules for artificial lung devices with improved thromboresistance and without degradation of gas transfer.
    No preview · Article · Feb 2015 · Langmuir
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    ABSTRACT: The objective of this work was to conduct pre-clinical feasibility studies to determine if a highly efficient, active-mixing, adult extracorporeal carbon dioxide removal (ECCO2R) system can safely be translated to the pediatric population. The Hemolung Respiratory Assist System (RAS) was tested in vitro and in vivo to evaluate its performance for pediatric veno-venous applications. The Hemolung RAS operates at blood flows of 350-550 ml/min and utilizes an integrated pump-gas exchange cartridge with a membrane surface area of 0.59 m2 as the only component of the extracorporeal circuit. Both acute and seven-day chronic in vivo tests were conducted in healthy juvenile sheep using a veno-venous cannulation strategy adapted to the in vivo model. The Hemolung RAS was found to have gas exchange and pumping capabilities relevant to patients weighing 3-25 kg. Seven-day animal studies in juvenile sheep demonstrated that veno-venous extracorporeal support could be used safely and effectively with no significant adverse reactions related to device operation.
    No preview · Article · Jan 2015 · The International journal of artificial organs
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    Preview · Article · Jan 2015
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    ABSTRACT: Adult extracorporeal carbon dioxide removal (ECCO2R) systems and pediatric ECMO share the common objectives of having a low blood flow rate and low priming volume while safely maintaining sufficient respiratory support. The Hemolung is a highly simplified adult ECCO2R system intended for partial respiratory support in adult patients with acute hypercapnic respiratory failure. The objective of this work was to conduct pre-clinical feasibility studies to determine if a highly efficient, active-mixing, adult ECCO2R system can safely be translated to the pediatric population. Methods. 14 healthy nonsedated juvenile sheep were used for acute (2 animals) and 7-day chronic (12 animals) in-vivo studies to evaluate treatment safety independently of respiratory related injuries. In all evaluations, we hypothesized that gas exchange capabilities of the Hemolung RAS in this model would be equivalent to the adult configuration performance at similar blood flows - minimum CO2 removal of 50 mL/min at a venous partial pressure of CO2 equal to 45 mmHg. Target blood flow rates were set to a minimum of 280 mL/min. Swan Ganz catheters were used under general anesthesia in the two acute subjects to evaluate blood gas status in the pulmonary artery.Results. The Hemolung RAS was found to have adequate gas exchange and pumping capabilities for full respiratory support for subjects weighing 3 – 25 kg. The Hemolung device was estimated to provide a partial respiratory support for subjects weighing 27 – 34 kg. The seven-day studies in juvenile sheep demonstrated that veno-venous extracorporeal support could be provided safely at low flows with no significant adverse reactions related to device operation.Conclusion. The study outcomes suggest the potential use of the Hemolung RAS in a veno-venous pediatric configuration to safely provide respiratory support utilizing a significantly less complex system than traditional pediatric ECMO.
    Preview · Article · Dec 2014
  • Y.Mussin · D.Bulanin · G.Jeffries · Zh.Zhumadilov · F.Olzhayev · W. Federspiel

    No preview · Conference Paper · Nov 2014
  • Y.Mussin · D.Bulanin · G.Jeffries · Zh.Zhumadilov · F.Olzhayev · W. Federspiel

    No preview · Conference Paper · Nov 2014
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    ABSTRACT: Introduction Prior work suggests that leukocyte trafficking is determined by local chemokine gradients between the nidus of infection and the plasma. We recently demonstrated that therapeutic apheresis can alter immune mediator concentrations in the plasma, protect against organ injury, and improve survival. Here we aimed to determine whether the removal of chemokines from the plasma by apheresis in experimental peritonitis changes chemokine gradients and subsequently enhances leukocyte localization into the infected compartment, and away from healthy tissues. Methods In total, 76 male adult Sprague–Dawley rats weighing 400 g to 600 g were included in this study. Eighteen hours after inducing sepsis by cecal ligation and puncture, we randomized these rats to apheresis or sham treatment for 4 hours. Cytokines, chemokines, and leukocyte counts from blood, peritoneal cavity, and lung were measured. In a separate experiment, we labeled neutrophils from septic donor animals and injected them into either apheresis or sham-treated animals. All numeric data with normal distributions were compared with one-way analysis of variance, and numeric data not normally distributed were compared with the Mann–Whitney U test. Results Apheresis significantly removed plasma cytokines and chemokines, increased peritoneal fluid-to-blood chemokine (C-X-C motif ligand 1, ligand 2, and C-C motif ligand 2) ratios, and decreased bronchoalveolar lavage fluid-to-blood chemokine ratios, resulting in enhanced leukocyte recruitment into the peritoneal cavity and improved bacterial clearance, but decreased recruitment into the lung. Apheresis also reduced myeloperoxidase activity and histologic injury in the lung, liver, and kidney. These Labeled donor neutrophils exhibited decreased localization in the lung when infused into apheresis-treated animals. Conclusions Our results support the concept of chemokine gradient control of leukocyte trafficking and demonstrate the efficacy of apheresis to target this mechanism and reduce leukocyte infiltration into the lung.
    Full-text · Article · Jul 2014 · Critical care (London, England)
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    ABSTRACT: Providing partial respiratory assistance by removing carbon dioxide (CO2) can improve clinical outcomes in patients suffering from acute exacerbations of chronic obstructive pulmonary disease and acute respiratory distress syndrome. An intravenous respiratory assist device with a small (25 Fr) insertion diameter eliminates the complexity and potential complications associated with external blood circuitry and can be inserted by nonspecialized surgeons. The impeller percutaneous respiratory assist catheter (IPRAC) is a highly efficient CO2 removal device for percutaneous insertion to the vena cava via the right jugular or right femoral vein that utilizes an array of impellers rotating within a hollow-fiber membrane bundle to enhance gas exchange. The objective of this study was to evaluate the effects of new impeller designs and impeller spacing on gas exchange in the IPRAC using computational fluid dynamics (CFD) and in vitro deionized water gas exchange testing. A CFD gas exchange and flow model was developed to guide a progressive impeller design process. Six impeller blade geometries were designed and tested in vitro in an IPRAC device with 2- or 10-mm axial spacing and varying numbers of blades (2–5). The maximum CO2 removal efficiency (exchange per unit surface area) achieved was 573 ± 8 mL/min/m2 (40.1 mL/min absolute). The gas exchange rate was found to be largely independent of blade design and number of blades for the impellers tested but increased significantly (5–10%) with reduced axial spacing allowing for additional shaft impellers (23 vs. 14). CFD gas exchange predictions were within 2–13% of experimental values and accurately predicted the relative improvement with impellers at 2- versus 10-mm axial spacing. The ability of CFD simulation to accurately forecast the effects of influential design parameters suggests it can be used to identify impeller traits that profoundly affect facilitated gas exchange.
    No preview · Article · May 2014 · Artificial Organs
  • Ayan Sen · John Kellum · William Federspiel
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    ABSTRACT: Introduction: Extracorporeal carbondioxide (CO2) removal (ECCOR) may enable lung protective ventilation (LPV) in Acute Respiratory Distress Syndrome (ARDS) by further reduction in minute ventilation and preventing hypercarbia. It can also avoid intubation and mechanical ventilation in primary hypercarbic respiratory failure as in acute COPD (chronic obstructive pulmonary disease)etc. ECCOR in the form of continuous hemodialysis offers an alternative, more available strategy compared to mechanical artificial lung technologies. However, previous attempts using continuous venovenous hemodialysis (CVVHD) have been limited by metabolic acidosis (MA). Methods: An in-vitro model was designed to develop and test a dialysate solution designed to remove bicarbonate. Freshly drawn bovine blood was used. CO2 was added to it using a Minimax plus hollow fiber oxygenator (Medtronic, Anaheim CA, USA) with a sweep gas composed of N2 and CO2 to simulate hypercarbic respiratory acidosis. The hypercarbic blood was pumped at blood flow rate (220 ml/min) and passed through an M10 dialysis filter (Gambro, Lyon France)with surface area of 0.04 m-sq. A zero bicarbonate dialysate solution was constituted using Stewart's physico-chemical approach designed to control the strong ion difference rather than replacing bicarbonate. Hemolysis was tested by measuring pre and post-LDH levels. Results: Our in vitro data shows successful removal of CO2 from hypercarbic bovine blood in vitro model using a zero bicarbonate dialysate without causing metabolic acidosis. CO2 removal was highly dependent on dialysate flows. Total CO2 removal was 70-120 ml/min (30-48% of production- similar to mechanical ECCOR devices) at IHD (Intermittent Hemodialysis) flow rate and 4-8 ml/min (1-3%) at standard CVVHD flows. Dose response saturation occurred at 240 ml/kg/hr of dialysate flow (IHD flow rate). LDH levels decreased by mean of 22.5% (5.8% standard deviation) in post-filter blood indicating no obvious hemolysis. Conclusions: Zero bicarbonate dialysis solutions can help in ECCOR without causing MA and enable application of LPV by limiting hypercarbia.
    No preview · Conference Paper · Dec 2013
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    Laura W Lund · William J Federspiel
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    ABSTRACT: For patients experiencing acute respiratory failure due to a severe exacerbation of chronic obstructive pulmonary disease (COPD), noninvasive positive pressure ventilation has been shown to significantly reduce mortality and hospital length of stay compared to respiratory support with invasive mechanical ventilation. Despite continued improvements in the administration of noninvasive ventilation (NIV), refractory hypercapnia and hypercapnic acidosis continue to prevent its successful use in many patients. Recent advances in extracorporeal gas exchange technology have led to the development of systems designed to be safer and simpler by focusing on the clinical benefits of partial extracorporeal carbon dioxide removal (ECCO2R), as opposed to full cardiopulmonary support. While the use of ECCO2R has been studied in the treatment of acute respiratory distress syndrome (ARDS), its use for acute hypercapnic respiratory during COPD exacerbations has not been evaluated until recently. This review will focus on literature published over the last year on the use of ECCO2R for removing extra CO2 in patients experiencing an acute exacerbation of COPD.
    Full-text · Article · Sep 2013
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    J D Kimmel · D T Arazawa · S-H Ye · V Shankarraman · W R Wagner · W J Federspiel
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    ABSTRACT: Extracorporeal CO2 removal from circulating blood is a promising therapeutic modality for the treatment of acute respiratory failure. The enzyme carbonic anhydrase accelerates CO2 removal within gas exchange devices by locally catalyzing HCO3 (-) into gaseous CO2 within the blood. In this work, we covalently immobilized carbonic anhydrase on the surface of polypropylene hollow fiber membranes using glutaraldehyde activated chitosan tethering to amplify the density of reactive amine functional groups for enzyme immobilization. XPS and a colorimetric amine assay confirmed higher amine densities on the chitosan coated fiber compared to control fiber. Chitosan/CA coated fibers exhibited accelerated CO2 removal in scaled-down gas exchange devices in buffer and blood (115 % enhancement vs. control, 37 % enhancement vs. control, respectively). Carbonic anhydrase immobilized directly on hollow fiber membranes without chitosan tethering resulted in no enhancement in CO2 removal. Additionally, fibers coated with chitosan/carbonic anhydrase demonstrated reduced platelet adhesion when exposed to blood compared to control and heparin coated fibers.
    Full-text · Article · Jul 2013 · Journal of Materials Science Materials in Medicine
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    ABSTRACT: Introduction: Promising preclinical results have been obtained with blood purification therapies as adjuvant treatment for sepsis. However, the mechanisms by which these therapies exert beneficial effects remain unclear. Some investigators have suggested that removal of activated leukocytes from the circulation might help ameliorate remote organ injury. We designed an extracorporeal hemoadsorption device capable of capturing both cytokines and leukocytes in order to test the hypothesis that leukocyte capture would alter circulating cytokine profiles and influence immunological cell-cell interactions in whole blood taken from patients with sepsis. Methods: We performed a series of ex vivo studies in 21 patients with septic shock and 12 healthy volunteers. Blood circulated for four hours in closed loops with four specially designed miniaturized extracorporeal blood purification devices including two different hemoadsorption devices and a hemofilter in order to characterize leukocyte capture and to assess the effects of leukocyte removal on inflammation and immune function. Results: Hemoadsorption was selective for removal of activated neutrophils and monocytes. Capture of these cells led to local release of certain cytokines, especially IL-8, and resulted in complex cell-cell interactions involved in cell-mediated immunity. Inhibition of cell adherence reversed the cytokine release and the effects on lymphocyte function. Conclusions: Monocyte and neutrophil capture using a sorbent polymer results in upregulation of IL-8 and modulation of cell-mediated immunity. Further studies are needed to understand better these cellular interactions in order to help design better blood purification therapies.
    Full-text · Article · Mar 2013 · Critical care (London, England)
  • Azadeh Alikhani · William J Federspiel
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    ABSTRACT: Anti-A/B antibody removal from blood in the peritransplantation period facilitates ABO-incompatible transplantation and significantly increases the donor pool. We have been developing an anti-A/B immunoadsorption device (BSAF), compatible with whole blood perfusion. The BSAF is based on integrated microfiltration hollow fibers with antibody capturing beads uniformly distributed within the fiber interstitial space. In this study we fabricated BSAF prototypes, appropriately scaled down from a conceptual clinical scale device. We then, for the first time, measured the time course of anti-A capture from blood samples recirculating through the scaled down BSAF devices. We observed a significant reduction in IgM (96% ± 5%, n = 5, p < 0.001), and IgG (81% ± 18%, n = 5, p < 0.05) anti-A antibody titers within 2 h. We did not observe a significant change between the initial and final values of hematocrit, total plasma protein concentration, plasma free hemoglobin concentration, and anti-B antibody titer over five experiments. In conclusion we showed that the BSAF modules selectively removed anti-A antibodies from blood in a simple one step process, without requiring a separate plasmapheresis unit. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
    No preview · Article · Nov 2012 · Journal of Biomedical Materials Research Part B Applied Biomaterials

Publication Stats

1k Citations
308.80 Total Impact Points

Institutions

  • 1996-2015
    • University of Pittsburgh
      • • Department of Medicine
      • • McGowan Institute for Regenerative Medicine
      • • Bioengineering
      • • Department of Surgery
      • • Chemical and Petroleum Engineering
      Pittsburgh, Pennsylvania, United States
  • 2006
    • University of Louisville
      • Department of Surgery
      Louisville, Kentucky, United States
  • 2002
    • Childrens Hospital of Pittsburgh
      • Division of Pediatric Otolaryngology (ENT)
      Pittsburgh, Pennsylvania, United States