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Trivedi A, Potter DR, Miyazawa BY, Lin M, Vivona LR, Khakoo MA, Antebi B, Lee A, Ishler B, Dickerson M, Kozar R, Schreiber MA, Holcomb JB, Fitzpatrick GM, Pati S. Freeze-dried platelets promote clot formation, attenuate endothelial cell permeability, and decrease pulmonary vascular leak in a murine model of hemorrhagic shock. J Trauma Acute Care Surg 2021; 90:203-214. [PMID: 33060537 DOI: 10.1097/ta.0000000000002984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Hemorrhagic shock (HS) and trauma induce endothelial barrier compromise, inflammation, and aberrant clotting. We have shown that fresh human platelets (Plts) and Plt extracellular vesicles mitigate vascular leak in murine models of injury. Here, we investigate the potential of freeze-dried platelets (FDPlts) to attenuate pulmonary vascular permeability, decrease inflammation, and promote clotting in a murine model of HS. METHODS Human FDPlts were characterized using in vitro assays of Plt marker expression, aggregation, coagulation, and endothelial cell permeability. An intravital model of vascular injury in the mouse cremaster muscle was used to assess the ability of FDPlts to incorporate into clots. Mouse groups subjected to controlled hemorrhage for 90 minutes were (1) lactated Ringer solution (LR), (2) FDPlts, (3) fresh human Plts, (4) murine whole blood (WB), and (5) shams (only instrumented). Hemorrhagic shock mouse endpoints included coagulation, pulmonary vascular permeability, and lung injury. RESULTS Freeze-dried Plts expressed Plt-specific markers and retained functionality similar to fresh Plts. In in vitro assays of Plt aggregation, differences were noted. In vivo, FDPlts and Plts were found to incorporate into clots in postcapillary venules in the mouse cremaster muscle. Hemorrhagic shock mice resuscitated with LR displayed increased pulmonary vascular permeability compared with sham (sham, 686.6 ± 359.7; shock-LR, 2,637 ± 954.7; p = 0.001), and treatment with FDPlts or WB attenuated permeability compared with shock: shock-FDPlts, 1,328 ± 462.6 (p = 0.05), and shock-WB, 1,024 ± 370.5 (p = 0.0108). However, human Plts (Days 1-3) did not attenuate vascular leak in HS mice compared with shock-LR (shock-Plts, 3,601 ± 1,581; p = 0.33). CONCLUSION FDPlts contribute to clot formation similar to fresh human Plts. FDPlts also attenuated vascular permeability in vitro and in vivo. Mouse WB resuscitation but not fresh human Plts attenuated vascular permeability after HS. These data suggest that the effect of FDPlts may be a suitable alternative to fresh Plts in modulating hemostasis and the endotheliopathy associated with injury.
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Affiliation(s)
- Alpa Trivedi
- From the Department of Laboratory Medicine (A.T., D.R.P., B.Y.M., M.L., L.R.V., M.A.K., S.P.), University of California, San Francisco, San Francisco, California; Cellphire (B.A., A.L., B.I., M.D., G.M.F.), Rockville; Shock Trauma Center (R.K.), University of Maryland School of Medicine, Baltimore, Maryland; Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery (M.A.S.), Oregon Health and Science University, Portland, Oregon; and Division of Acute Care Surgery (J.B.H.), University of Alabama School of Medicine, Birmingham, Alabama
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Pati S, Peng Z, Wataha K, Miyazawa B, Potter DR, Kozar RA. Lyophilized plasma attenuates vascular permeability, inflammation and lung injury in hemorrhagic shock. PLoS One 2018; 13:e0192363. [PMID: 29394283 PMCID: PMC5796727 DOI: 10.1371/journal.pone.0192363] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/21/2018] [Indexed: 11/18/2022] Open
Abstract
In severe trauma and hemorrhage the early and empiric use of fresh frozen plasma (FFP) is associated with decreased morbidity and mortality. However, utilization of FFP comes with the significant burden of shipping and storage of frozen blood products. Dried or lyophilized plasma (LP) can be stored at room temperature, transported easily, reconstituted rapidly with ready availability in remote and austere environments. We have previously demonstrated that FFP mitigates the endothelial injury that ensues after hemorrhagic shock (HS). In the current study, we sought to determine whether LP has similar properties to FFP in its ability to modulate endothelial dysfunction in vitro and in vivo. Single donor LP was compared to single donor FFP using the following measures of endothelial cell (EC) function in vitro: permeability and transendothelial monolayer resistance; adherens junction preservation; and leukocyte-EC adhesion. In vivo, using a model of murine HS, LP and FFP were compared in measures of HS- induced pulmonary vascular inflammation and edema. Both in vitro and in vivo in all measures of EC function, LP demonstrated similar effects to FFP. Both FFP and LP similarly reduced EC permeability, increased transendothelial resistance, decreased leukocyte-EC binding and persevered adherens junctions. In vivo, LP and FFP both comparably reduced pulmonary injury, inflammation and vascular leak. Both FFP and LP have similar potent protective effects on the vascular endothelium in vitro and in lung function in vivo following hemorrhagic shock. These data support the further development of LP as an effective plasma product for human use after trauma and hemorrhagic shock.
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Affiliation(s)
- Shibani Pati
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Zhanglong Peng
- Department of Anesthesia, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Katherine Wataha
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Byron Miyazawa
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Daniel R Potter
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Rosemary A Kozar
- Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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Potter DR, Miyazawa BY, Gibb SL, Deng X, Togaratti PP, Croze RH, Srivastava AK, Trivedi A, Matthay M, Holcomb JB, Schreiber MA, Pati S. Mesenchymal stem cell-derived extracellular vesicles attenuate pulmonary vascular permeability and lung injury induced by hemorrhagic shock and trauma. J Trauma Acute Care Surg 2018; 84:245-256. [PMID: 29251710 PMCID: PMC6378956 DOI: 10.1097/ta.0000000000001744] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Mesenchymal stem cells (MSCs) have been shown to mitigate vascular permeability in hemorrhagic shock (HS) and trauma-induced brain and lung injury. Mechanistically, paracrine factors secreted from MSCs have been identified that can recapitulate many of the potent biologic effects of MSCs in animal models of disease. Interestingly, MSC-derived extracellular vesicles (EVs), contain many of these key soluble factors, and have therapeutic potential independent of the parent cells. In this study we sought to determine whether MSC-derived EVs (MSC EVs) could recapitulate the beneficial therapeutic effects of MSCs on lung vascular permeability induced by HS in mice. METHODS Mesenchymal stem cell EVs were isolated from human bone marrow-derived MSCs by ultracentrifugation. A mouse model of fixed pressure HS was used to study the effects of shock, shock + MSCs and shock + MSC EVs on lung vascular endothelial permeability. Mice were administered MSCs, MSC EVs, or saline IV. Lung tissue was harvested and assayed for permeability, RhoA/Rac1 activation, and for differential phosphoprotein expression. In vitro, human lung microvascular cells junctional integrity was evaluated by immunocytochemistry and endothelial cell impedance assays. RESULTS Hemorrhagic shock-induced lung vascular permeability was significantly decreased by both MSC and MSC EV infusion. Phosphoprotein profiling of lung tissue revealed differential activation of proteins and pathways related to cytoskeletal rearrangement and regulation of vascular permeability by MSCs and MSC EVs. Lung tissue from treatment groups demonstrated decreased activation of the cytoskeletal GTPase RhoA. In vitro, human lung microvascular cells, MSC CM but not MSC-EVs prevented thrombin-induced endothelial cell permeability as measured by electrical cell-substrate impedance sensing system and immunocytochemistry of VE-cadherin and actin. CONCLUSION Mesenchymal stem cells and MSC EVs modulate cytoskeletal signaling and attenuate lung vascular permeability after HS. Mesenchymal stem cell EVs may potentially be used as a novel "stem cell free" therapeutic to treat HS-induced lung injury.
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Affiliation(s)
- Daniel R. Potter
- Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California
| | - Byron Y. Miyazawa
- Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California
| | - Stuart L. Gibb
- Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California
| | - Xutao Deng
- Blood Systems Research Institute, San Francisco, California
| | | | - Roxanne H. Croze
- Cardiovascular Research Institute, University of California, San Francisco
| | - Amit K. Srivastava
- Department of Pediatric Surgery, McGovern Medical School, University of Texas Health Sciences Center at Houston, Houston, Texas
| | - Alpa Trivedi
- Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California
| | - Michael Matthay
- Cardiovascular Research Institute, University of California, San Francisco
| | | | | | - Shibani Pati
- Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California
- Blood Systems Research Institute, San Francisco, California
- Corresponding author- , (415) 502-1634. Department of Laboratory Medicine, 513 Parnassus Avenue, HSE 760, San Francisco, CA 94143
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Baimukanova G, Miyazawa B, Potter DR, Gibb SL, Keating S, Danesh A, Beyer A, Dayter Y, Bruhn R, Muench MO, Cap AP, Norris PJ, Spinella P, Cohen M, Pati S. The effects of 22°C and 4°C storage of platelets on vascular endothelial integrity and function. Transfusion 2016; 56 Suppl 1:S52-64. [PMID: 27001362 DOI: 10.1111/trf.13455] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Although a majority of the studies conducted to date on platelet (PLT) storage have been focused on PLT hemostatic function, the effects of 4°C PLTs on regulation of endothelial barrier permeability are still not known. In this study, we compared the effects of room temperature (22°C) stored and (4°C) stored PLTs on the regulation of vascular endothelial cell (EC) permeability in vitro and in vivo. STUDY DESIGN AND METHODS Day 1, Day 5, and Day 7 leukoreduced apheresis PLTs stored at 4 or 22°C were studied in vitro and in vivo. In vitro, PLT effects on EC permeability and barrier function, adhesion, and impedance aggregometry were investigated. In vivo, using a mouse model of vascular leak, attenuation of vascular leak and circulating PLT numbers were measured. RESULTS Treatment of EC monolayers with Day 5 or Day 7 PLTs, stored at both 22°C and 4°C, resulted in similar decreases in EC permeability on average. However, analysis of individual samples revealed significant variation that was donor dependent. Additional in vitro measurements revealed a decrease in inflammatory mediators, nonspecific PLT-endothelial aggregation and attenuated loss of aggregation over time to TRAP, ASPI, ADP, and collagen with 4°C storage. In mice, while 22°C and 4°C PLTs both demonstrated significant protection against vascular endothelial growth factor A (VEGF-A)-induced vascular leak 22°C PLTs exhibited increased protection compared to 4°C PLTs. Systemic circulating levels of 4°C PLTs were decreased compared to 22°C PLTs. CONCLUSIONS In vitro, 4°C-stored PLTs exhibit a greater capacity to inhibit EC permeability than 22°C-stored PLTs. In vivo, 22°C PLTs provide superior control of vascular leak induced by VEGF-A. This discrepancy may be due to increased clearance of 4°C PLTs from the systemic circulation.
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Affiliation(s)
- Gyulnar Baimukanova
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Byron Miyazawa
- Department of Surgery, University of California, San Francisco, California
| | - Daniel R Potter
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Stuart L Gibb
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Sheila Keating
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Ali Danesh
- Blood Systems Research Institute, University of California, San Francisco, California.,Department of Laboratory Medicine, University of California, San Francisco, California
| | - Ashley Beyer
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Yelena Dayter
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Roberta Bruhn
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Marcus O Muench
- Blood Systems Research Institute, University of California, San Francisco, California
| | - Andrew P Cap
- Coagulation and Blood Research Program, US Army Institute of Surgical Research, JBSA-FT Sam Houston, Texas
| | - Philip J Norris
- Blood Systems Research Institute, University of California, San Francisco, California.,Department of Laboratory Medicine, University of California, San Francisco, California
| | - Philip Spinella
- Department of Pediatrics, Washington University in St Louis, St Louis, Missouri
| | - Mitchell Cohen
- Department of Surgery, University of California, San Francisco, California
| | - Shibani Pati
- Blood Systems Research Institute, University of California, San Francisco, California.,Department of Laboratory Medicine, University of California, San Francisco, California
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Baimukanova G, Miyazawa B, Potter DR, Muench MO, Bruhn R, Gibb SL, Spinella PC, Cap AP, Cohen MJ, Pati S. Platelets regulate vascular endothelial stability: assessing the storage lesion and donor variability of apheresis platelets. Transfusion 2016; 56 Suppl 1:S65-75. [PMID: 27001364 DOI: 10.1111/trf.13532] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 01/09/2016] [Accepted: 01/09/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND In current blood banking practices, platelets (PLTs) are stored in plasma at 22°C, with gentle agitation for up to 5 days. To date, the effects of storage and donor variability on PLT regulation of vascular integrity are not known. STUDY DESIGN AND METHODS In this study, we examined the donor variability of leukoreduced fresh (Day 1) or stored (Day 5) PLTs on vascular endothelial barrier function in vitro and in vivo. In vitro, PLT effects on endothelial cell (EC) monolayer permeability were assessed by analyzing transendothelial electrical resistances (TEER). PLT aggregation, a measure of hemostatic potential, was analyzed by impedance aggregometry. In vivo, PLTs were investigated in a vascular endothelial growth factor A (VEGF-A)-induced vascular permeability model in NSG mice, and PLT circulation was measured by flow cytometry. RESULTS Treatment of endothelial monolayers with fresh Day 1 PLTs resulted in an increase in EC barrier resistance and decreased permeability in a dose-dependent manner. Subsequent treatment of EC monolayers with Day 5 PLTs demonstrated diminished vasculoprotective effects. Donor variability was noted in all measures of PLT function. Day 1 PLT donors were more variable in their effects on TEER than Day 5 PLTs. In mice, while all PLTs regardless of storage time demonstrated significant protection against VEGF-A-induced vascular leakage, Day 5 PLTs exhibited reduced protection when compared to Day 1 PLTs. Day 1 PLTs demonstrated significant donor variability against VEGF-A-challenged vascular leakage in vivo. Systemic circulating levels of Day 1 PLTs were higher than those of Day 5 PLTs CONCLUSIONS In vitro and in vivo, Day 1 PLTs are protective in measures of vascular endothelial permeability. Donor variability is most prominent in Day 1 PLTs. A decrease in the protective effects is found with storage of the PLT units between Day 1 and Day 5 at 22°C, thereby suggesting that Day 5 PLTs are diminished in their ability to attenuate vascular endothelial permeability.
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Affiliation(s)
| | - Byron Miyazawa
- Department of Surgery, University of California at San Francisco, San Francisco, California
| | | | | | - Roberta Bruhn
- Blood Systems Research Institute, San Francisco, California
| | - Stuart L Gibb
- Blood Systems Research Institute, San Francisco, California
| | - Philip C Spinella
- Division of Critical Care Medicine, Department of Pediatrics, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Andrew P Cap
- US Army Institute of Surgical Research (USAISR), JBSA-FT Sam Houston, Texas
| | - Mitchell J Cohen
- Department of Surgery, University of California at San Francisco, San Francisco, California
| | - Shibani Pati
- Blood Systems Research Institute, San Francisco, California.,Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California
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Stephens RM, Potter DR, Howard ER, Hallett R. The rehabilitation of a ventilator dependent child using diaphragmatic stimulation. Clin Rehabil 2016. [DOI: 10.1177/026921559100500307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The rehabilitation of a male child who remained tetraplegic and ventilator dependent after Haemophilus influenzae meningitis at the age of 18 months is described. Diaphragm pacing, per phrenic electrical stimulation of the diaphragm, has been used in the USA, but at the time only one patient had been managed with this technique in the UK. Successful rehabilitation of this adult patient at King's College Hospital prompted the application of the technique to the child here described. At the age of 34 months the integrity of the phrenic nerves had been confirmed, and bilateral phrenic electrodes and pacing receivers were implanted. The patient is now 12 years old, and has been using diaphragm pacing for nine years. His rehabilitation, social integration, and education have relied on this method of artificial ventilation, the advantages and disadvantages of which are described.
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Potter DR, van Teeffelen J, Vink H, van den Berg BM. Perturbed mechanotransduction by endothelial surface glycocalyx modification greatly impairs the arteriogenic process. Am J Physiol Heart Circ Physiol 2015; 309:H711-7. [PMID: 26071545 DOI: 10.1152/ajpheart.00257.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 06/03/2015] [Indexed: 12/13/2022]
Abstract
The mechanisms that trigger initiation of arteriogenesis in response to pathogenic obstruction of arterial flow are not fully understood. Our objective is to determine whether glycocalyx mediated mechanotransduction of fluid shear stress to the endothelial layer is an essential first step in inducing arteriogenesis. Mice were implanted with an osmotic minipump containing saline or hyaluronan synthase inhibitor 4-methylesculetin (4ME) 2 wk before femoral artery ligation. 4ME was effective in modifying the endothelial glycocalyx as measured by dextran exclusion and perfused boundary region changes. Glycocalyx modification resulted in a 52% (P = 0.002) reduction in perfusion restoration through the 21-day follow-up [area under the curve, 4.9 ± 1.1 (n = 11) vs. 10.2 ± 3.2 (n = 10), 4ME vs. control (Ctrl)]. Upon femoral artery ligation, no change in collateral vessel diameter in 4ME treated mice (49.8 ± 26.3 vs. 47.1 ± 14.0 μm, ligated vs unligated) was observed (Ctrl, 88.5 ± 18.8 vs. 35.1 ± 3.0 μm, ligated vs unligated, P < 0.05). This impaired arteriogenic process was accompanied by lack of local induction of both endothelial and smooth muscle cell activation (Ki67, endothelial nitric oxide synthase, and ICAM-1), as well as a failure to recruit CD11b-positive cells in 4ME-treated collateral vessels (0.012 ± 0.003 vs. 0.010 ± 0.003 cells/μm vessel perimeter, ligated vs. unligated), whereas in Ctrls, the number of CD11b cells was increased (0.024 ± 0.002 vs. 0.010 ± 0.004 cells/μm vessel perimeter, P < 0.05). Modification of the glycocalyx by inhibition of hyaluronan synthesis renders the endothelium unresponsive to altered hemodynamic conditions resulting from femoral artery ligation, which results in a hampered restoration of distal perfusion.
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Affiliation(s)
- Daniel R Potter
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands
| | - Jurgen van Teeffelen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands
| | - Hans Vink
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands
| | - Bernard M van den Berg
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, The Netherlands
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Abstract
Compelling evidence continues to emerge suggesting that the glycocalyx surface layer on vascular endothelial cells plays a determining role in numerous physiological processes including inflammation, microvascular permeability, and endothelial mechanotransduction. Previous research has shown that enzymes degrade the glycocalyx, whereas inflammation causes shedding of the layer. To track the endogenous recovery of the glycocalyx in vivo, we used fluorescent microparticle image velocimetry (micro-PIV) in mouse cremaster muscle venules to estimate the hydrodynamically relevant glycocalyx thickness 1, 3, 5, and 7 days after enzymatic or cytokine-mediated degradation of the layer. Results indicate that after acute degradation of the glycocalyx, 5 to 7 days are required for the layer to endogenously restore itself to its native hydrodynamically relevant thickness in vivo. In light of these findings, and because demonstrable evidence has emerged that standard cell culture conditions are not conducive to providing the environment and/or cellular conditions necessary to produce and maintain a physiologically relevant cell surface glycocalyx in vitro, we sought to determine whether merely the passage of time would be sufficient to promote the production of a hydrodynamically relevant glycocalyx on a confluent monolayer of human umbilical vein endothelial cells (HUVECs). Using micro-PIV, we found that the hydrodynamically relevant glycocalyx was substantially absent 7 days postconfluence on HUVEC-lined cylindrical collagen microchannels maintained under standard culture conditions. Thus, it remains to be determined how a hydrodynamically relevant glycocalyx surface layer can be synthesized and maintained in culture before the endothelial cell culture model can be used to elucidate glycocalyx-mediated mechanisms of endothelial cell function.
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Affiliation(s)
- Daniel R Potter
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
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Abstract
In recent years, the endothelial cell surface glycocalyx has emerged as a structure of fundamental importance to a broad range of phenomena that determine cardiovascular health and disease. This new understanding of the functional significance of the glycocalyx has been made possible through recently developed experimental techniques using intravital microscopy that are capable of directly probing the glycocalyx in vivo. Using fluorescent microparticle image velocimetry in venules and endothelialized cylindrical collagen microchannels, we show that the hydrodynamically relevant endothelial cell glycocalyx surface layer observed in microvessels in vivo (0.52±0.28 μm thickness), which is a fundamental determinant of the hydrodynamic and mechanical environment at the endothelial cell surface, is absent from human umbilical vein (0.03±0.04 μm thickness) and bovine aortic (0.02±0.04 μm thickness) endothelial cells grown and maintained under standard cell culture conditions in vitro. An endothelial surface–bound glycosaminoglycan layer, not necessarily indicative of but having similar hydrodynamic properties to the endothelial glycocalyx observed in vivo, was detected (0.21±0.27 μm thickness) only after hyaluronan and chondroitin sulfate were added to the cell culture media at hyperphysiological concentrations (0.2 mg/mL perfused for 75 minutes). The implications of this glycocalyx deficiency under standard cell culture conditions in these pervasive in vitro models broadly impact a myriad of studies involving endothelial cell monolayers in which inferences are made that may depend on endothelial cell surface chemistry. In light of these findings, conclusions drawn from such studies in the areas of microvascular permeability, inflammation, mechanotransduction, and atherosclerosis must be carefully reconsidered.
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Affiliation(s)
- Daniel R. Potter
- From the Department of Biomedical Engineering, Boston University, Mass
| | - Edward R. Damiano
- From the Department of Biomedical Engineering, Boston University, Mass
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Chrobak KM, Potter DR, Tien J. Formation of perfused, functional microvascular tubes in vitro. Microvasc Res 2006; 71:185-96. [PMID: 16600313 DOI: 10.1016/j.mvr.2006.02.005] [Citation(s) in RCA: 382] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 01/18/2006] [Accepted: 02/20/2006] [Indexed: 11/23/2022]
Abstract
This work describes the formation, perfusion, and maturation of three-dimensional microvascular tubes in vitro. These tubes consisted of confluent monolayers of human endothelial cells that lined open, cylindrical channels within collagen gels. Perivascular cells could be directly embedded within the gels or added after endothelial cells grew to confluence. The tubes spanned the entire 5-7 mm extent of the gels; their diameters initially ranged from 55 to 120 microm and increased to 75-150 microm after maturation. Endothelial tubes displayed a strong barrier function over 5 days, resisted adhesion of leukocytes, and reacted quickly to inflammatory stimuli by breakdown of the barrier and support of leukocyte adhesion. These tubes resembled venules and "giant" capillaries in both their cellular organization and function, and we believe that they will serve as useful in vitro models of inflammation under constant perfusion.
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Affiliation(s)
- Kenneth M Chrobak
- Department of Biomedical Engineering, Boston University, MA 02215, USA
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Leech RC, Watts AD, Heaton ND, Potter DR. Intraoperative cardiac tamponade after central venous cannulation in an infant during orthotopic liver transplantation. Anesth Analg 1999; 89:342-3. [PMID: 10439745 DOI: 10.1097/00000539-199908000-00018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- R C Leech
- Department of Anaesthesia, King's College Hospital, Denmark Hill, London, United Kingdom
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Bromley PN, Cottam SJ, Hilmi I, Tan KC, Heaton N, Ginsburg R, Potter DR. Effects of intraoperative N-acetylcysteine in orthotopic liver transplantation. Br J Anaesth 1995; 75:352-4. [PMID: 7547057 DOI: 10.1093/bja/75.3.352] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
N-acetylcysteine (NAC) is an antioxidant agent which has been shown to benefit patients with fulminant hepatic failure. We have examined its effect in patients with chronic liver disease undergoing orthotopic liver transplantation by giving NAC during operation. In a prospective, randomized, double-blind, placebo-controlled study of 50 patients, NAC appeared to induce mild vasodilatation, improve oxygen delivery and consumption, and reduce base deficit, but data interpretation was difficult. There were no significant effects on mortality, morbidity or postoperative graft function.
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Affiliation(s)
- P N Bromley
- Department of Anaesthesia for Liver Transplantation, King's College Hospital, London
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Abstract
A previous report on the effect of the day of the full moon on the acting-out behavior of 20 developmentally delayed, institutionalized women showed that on the day of the full moon there were significantly more misbehaviors than on any other day during the lunar period. The records were re-evaluated to assess the frequency of acting-out behaviors on weekends and holidays as contrasted with the balance of the month. This re-evaluation indicated there was no significant difference between the weekends and holidays and the balance of the month (t = 1.14). The results were taken as support of the previous findings that on the day of the full moon there were significantly more misbehaviors than on any other day of the lunar period.
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Abstract
Over 19 lunar months reports of all aggressive acting-out misbehaviors as recorded by direct-care staff were evaluated and recorded on a day-by-day basis for a randomly selected sample of 20 developmentally delayed women, CA 18 to 50; MA, 9 to 18 months. All had been in continuous residence in a residential treatment center for a minimum of 31 months. A grid representing the 24-hr. period of the full moon (a), the three days prior to the day of the full moon (b), the three days after the full moon (c), and the balance of the lunar period (d) was placed over the record. Comparisons using the Duncan multiple-range test indicated that the mean number of misbehaviors on the day of the full moon was significantly higher than the mean number on any other day of the lunar period (the next highest was for the three days prior to the day of the full moon).
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Abstract
A case of a patient with tetanus is reported in whom an atracurium infusion and artificial ventilation were needed in addition to sedation to control the muscle spasms. The atracurium infusion was used for 71 days, the longest time ever recorded, at a mean rate of 1.3 mg/kg/hour at the end of infusion. The plasma atracurium and laudanosine concentrations were 1.5 micrograms/ml and 0.985 micrograms/ml respectively. Subsequently there was an exponential decline in the serum laudanosine concentration which had decreased to 0.014 micrograms/ml 24 hours later. These results suggest that prolonged use of atracurium by infusion is not associated with excessive cumulation of laudanosine when renal and hepatic function are normal.
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Affiliation(s)
- S J Peat
- Department of Anaesthesia, King's College Hospital, Camberwell, London
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Abstract
A closed loop control system for vasoactive drug infusion is described using a dedicated bedside microcomputer and a single volumetric infusion pump. The signal from an indwelling arterial cannula is taken from the bedside monitor through an analogue/digital converter to a microcomputer. After signal validation changes of infusion rate are calculated and communicated to a volumetric infusion pump through an RS 232 interface. The system has been successfully employed in four patients during cardiac surgery prior to cardiopulmonary bypass and in six cardiac surgical patients in the postoperative period. In both groups mean arterial pressure was controlled within 5 mmHg of target value for 75% of infusion time, and within 10 mmHg for 90% of the duration of infusion.
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Abstract
Diaphragm pacing, which entails electrical stimulation to the phrenic nerve, is an effective means of managing patients with ventilatory insufficiency and intact lowermotor-neurone innervation of the diaphragm. The pacing apparatus is used to pace the right and left hemidiaphragms alternately to avoid fatigue, which may damage the muscle irreversibly. Among the important benefits of pacing in quadriplegics with paralysis or respiratory muscles are the social and psychological advantages of not being dependent on a mechanical ventilator.
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Gil-Rodriguez JA, Payne JP, Potter DR. Some cardiovascular effects of intravenous atropine in patients anaesthetized with halothane. Br J Pharmacol 1970; 40:571P-572P. [PMID: 5531864 PMCID: PMC1703176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Potter DR, Paddle JS. The effect of passive hyperventilation during halothane anaesthesia on the ventilatory response to carbon dioxide. Br J Anaesth 1969; 41:191-2. [PMID: 5774523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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