1
|
Abstract
Endotoxaemia is an inflammatory condition which happens due to the presence of outer cell wall layer of Gram-negative bacteria in blood circulation, containing lipopolysaccharide commonly known as endotoxin. This condition causes high mortality in affected animals and sheep are highly susceptible in this regard. Several researchers have emphasised the therapeutic regimens of endotoxaemia and its sequels in sheep. Furthermore, sheep are among the most commonly used animal species in experimental studies on endotoxaemia, and for the past five decades, ovine models have been employed to evaluate different aspects of endotoxaemia. Currently, there are several studies on experimentally induced endotoxaemia in sheep, and information regarding novel therapeutic protocols in this species contributes to better understanding and treating the condition. This review aims to specifically introduce various treatment methods of endotoxaemia in sheep.
Collapse
Affiliation(s)
- A. Chalmeh
- Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| |
Collapse
|
2
|
Eliwan H, Omer M, McKenna E, Kelly LA, Nolan B, Regan I, Molloy EJ. Protein C Pathway in Paediatric and Neonatal Sepsis. Front Pediatr 2021; 9:562495. [PMID: 35186813 PMCID: PMC8849213 DOI: 10.3389/fped.2021.562495] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/20/2021] [Indexed: 11/24/2022] Open
Abstract
Protein C plays a major role in the physiological regulation of coagulation pathways through inactivation of factor Va, factor VIIIa, and plasminogen activator inhibitor. Protein C is involved in the control of inflammation during sepsis, by inhibiting release of pro-inflammatory cytokines, thereby controlling neutrophil, and monocyte effects on injured tissue. Recombinant human activated protein C (rhAPC) reduced mortality in adult sepsis in earlier studies but had no significant benefit in more recent trials. Protein C levels are reduced during paediatric and neonatal sepsis, which may play a major role in the development of disseminated intravascular thrombosis, purpura fulminans, and multiorgan dysfunction. The role of protein C in paediatric sepsis requires further clinical and immunological evaluation to define the patient subgroups who may benefit from this therapy. Newer versions of rhAPC are under development with less risk of haemorrhage potentially broadening the scope of this intervention.
Collapse
Affiliation(s)
- Hassan Eliwan
- National Children's Research Centre, Dublin, Ireland.,Department of Paediatrics, Trinity Translational Medicine Institute, Trinity College Dublin, Dublin, Ireland
| | - Murwan Omer
- Department of Paediatrics, Children's Health Ireland at Tallaght, Dublin, Ireland
| | - Ellen McKenna
- Department of Paediatrics, Trinity Translational Medicine Institute, Trinity College Dublin, Dublin, Ireland
| | - Lynne A Kelly
- National Children's Research Centre, Dublin, Ireland.,Department of Paediatrics, Trinity Translational Medicine Institute, Trinity College Dublin, Dublin, Ireland.,Trinity Research in Childhood Centre, Dublin, Ireland
| | - Beatrice Nolan
- Department of Haematology, Children's Health Ireland at Crumlin, Dublin, Ireland
| | - Irene Regan
- National Children's Research Centre, Dublin, Ireland.,Department of Haematology, Children's Health Ireland at Crumlin, Dublin, Ireland
| | - Eleanor J Molloy
- National Children's Research Centre, Dublin, Ireland.,Department of Paediatrics, Trinity Translational Medicine Institute, Trinity College Dublin, Dublin, Ireland.,Department of Paediatrics, Children's Health Ireland at Tallaght, Dublin, Ireland.,Trinity Research in Childhood Centre, Dublin, Ireland.,Department of Neonatology, Children's Health Ireland at Crumlin, Dublin, Ireland.,Department of Paediatrics, Coombe Women's and Infant's University Hospital, Dublin, Ireland
| |
Collapse
|
3
|
Dooley LM, Abdalmula A, Washington EA, Kaufman C, Tudor EM, Ghosh P, Itescu S, Kimpton WG, Bailey SR. Effect of mesenchymal precursor cells on the systemic inflammatory response and endothelial dysfunction in an ovine model of collagen-induced arthritis. PLoS One 2015; 10:e0124144. [PMID: 25950840 PMCID: PMC4423911 DOI: 10.1371/journal.pone.0124144] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 03/10/2015] [Indexed: 02/07/2023] Open
Abstract
Background and Aim Mesenchymal precursor cells (MPC) are reported to possess immunomodulatory properties that may prove beneficial in autoimmune and other inflammatory conditions. However, their mechanism of action is poorly understood. A collagen-induced arthritis model has been previously developed which demonstrates local joint inflammation and systemic inflammatory changes. These include not only increased levels of inflammatory markers, but also vascular endothelial cell dysfunction, characterised by reduced endothelium-dependent vasodilation. This study aimed to characterise the changes in systemic inflammatory markers and endothelial function following the intravenous administration of MPC, in the ovine model. Methods Arthritis was induced in sixteen adult sheep by administration of bovine type II collagen into the hock joint following initial sensitisation. After 24h, sheep were administered either 150 million allogeneic ovine MPCs intravenously, or saline only. Fibrinogen and serum amyloid-A were measured in plasma to assess systemic inflammation, along with pro-inflammatory and anti-inflammatory cytokines. Animals were necropsied two weeks following arthritis induction. Coronary and digital arterial segments were mounted in a Mulvaney-Halpern wire myograph. The relaxant response to endothelium-dependent and endothelium-independent vasodilators was used to assess endothelial dysfunction. Results and Conclusion Arthritic sheep treated with MPC demonstrated a marked spike in plasma IL-10, 24h following MPC administration. They also showed significantly reduced plasma levels of the inflammatory markers, fibrinogen and serum amyloid A, and increased HDL. Coronary arteries from RA sheep treated with MPCs demonstrated a significantly greater maximal relaxation to bradykinin when compared to untreated RA sheep (253.6 ± 17.1% of pre-contracted tone vs. 182.3 ± 27.3% in controls), and digital arteries also demonstrated greater endothelium-dependent vasodilation. This study demonstrated that MPCs given intravenously are able to attenuate systemic inflammatory changes associated with a monoarthritis, including the development of endothelial dysfunction.
Collapse
Affiliation(s)
- Laura M. Dooley
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Anwar Abdalmula
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | | | - Claire Kaufman
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Elizabeth M. Tudor
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Peter Ghosh
- Mesoblast Ltd, Melbourne, Victoria, Australia
| | | | - Wayne G. Kimpton
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Simon R. Bailey
- Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| |
Collapse
|
4
|
Sadowitz B, Roy S, Gatto LA, Habashi N, Nieman G. Lung injury induced by sepsis: lessons learned from large animal models and future directions for treatment. Expert Rev Anti Infect Ther 2014; 9:1169-78. [DOI: 10.1586/eri.11.141] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
5
|
Abstract
The acute respiratory distress syndrome (ARDS) is a major public health problem and a leading source of morbidity in intensive care units. Lung tissue in patients with ARDS is characterized by inflammation, with exuberant neutrophil infiltration, activation, and degranulation that is thought to initiate tissue injury through the release of proteases and oxygen radicals. Treatment of ARDS is supportive primarily because the underlying pathophysiology is poorly understood. This gap in knowledge must be addressed to identify urgently needed therapies. Recent research efforts in anti-inflammatory drug development have focused on identifying common control points in multiple signaling pathways. The protein kinase C (PKC) serine-threonine kinases are master regulators of proinflammatory signaling hubs, making them attractive therapeutic targets. Pharmacological inhibition of broad-spectrum PKC activity and, more importantly, of specific PKC isoforms (as well as deletion of PKCs in mice) exerts protective effects in various experimental models of lung injury. Furthermore, PKC isoforms have been implicated in inflammatory processes that may be involved in the pathophysiologic changes that result in ARDS, including activation of innate immune and endothelial cells, neutrophil trafficking to the lung, regulation of alveolar epithelial barrier functions, and control of neutrophil proinflammatory and prosurvival signaling. This review focuses on the mechanistic involvement of PKC isoforms in the pathogenesis of ARDS and highlights the potential of developing new therapeutic paradigms based on the selective inhibition (or activation) of specific PKC isoforms.
Collapse
|
6
|
Cornet AD, van Nieuw Amerongen GP, Beishuizen A, Schultz MJ, Girbes AR, Groeneveld AJ. Activated protein C in the treatment of acute lung injury and acute respiratory distress syndrome. Expert Opin Drug Discov 2013; 4:219-27. [PMID: 23489122 DOI: 10.1517/17460440902721204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) frequently necessitate mechanical ventilation in the intensive care unit. The syndromes have a high mortality rate and there is at present no treatment specifically directed at the underlying pathogenesis. Central in the pathophysiology of ALI/ARDS is alveolocapillary inflammation leading to permeability edema. As a result of the crosstalk between inflammation and coagulation, activation of proinflammatory and procoagulant/antifibrinolytic pathways contributes to disruption of the endothelial barrier. Protein C (PC) plays a central role in maintaining the equilibrium between coagulation and inflammation. Additionally, natural anticoagulants, such as PC, are depleted, both in blood as well as in the lung. Therefore, the PC system is of interest as a therapeutic target in patients with ALI/ARDS. METHOD This review is based on a Medline search of relevant basic and clinical studies. OBJECTIVE It discusses the potential role of activated PC in modulating the proinflammatory/procoagulant state for enhancing endothelial barrier function in animal models and human ALI/ARDS.
Collapse
Affiliation(s)
- Alexander D Cornet
- Department of Intensive Care, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands +31 20 4443933 ; +31 20 4442392 ;
| | | | | | | | | | | |
Collapse
|
7
|
Suborov EV, Smetkin AA, Kondratiev TV, Valkov AY, Kuzkov VV, Kirov MY, Bjertnaes LJ. Inhibitor of neuronal nitric oxide synthase improves gas exchange in ventilator-induced lung injury after pneumonectomy. BMC Anesthesiol 2012; 12:10. [PMID: 22720843 PMCID: PMC3441363 DOI: 10.1186/1471-2253-12-10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 06/06/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Mechanical ventilation with high tidal volumes may cause ventilator-induced lung injury (VILI) and enhanced generation of nitric oxide (NO). We demonstrated in sheep that pneumonectomy followed by injurious ventilation promotes pulmonary edema. We wished both to test the hypothesis that neuronal NOS (nNOS), which is distributed in airway epithelial and neuronal tissues, could be involved in the pathogenesis of VILI and we also aimed at investigating the influence of an inhibitor of nNOS on the course of VILI after pneumonectomy. METHODS Anesthetized sheep underwent right pneumonectomy, mechanical ventilation with tidal volumes (VT) of 6 mL/kg and FiO2 0.5, and were subsequently randomized to a protectively ventilated group (PROTV; n = 8) keeping VT and FiO2 unchanged, respiratory rate (RR) 25 inflations/min and PEEP 4 cm H2O for the following 8 hrs; an injuriously ventilated group with VT of 12 mL/kg, zero end-expiratory pressure, and FiO2 and RR unchanged (INJV; n = 8) and a group, which additionally received the inhibitor of nNOS, 7-nitroindazole (NI) 1.0 mg/kg/h intravenously from 2 hours after the commencement of injurious ventilation (INJV + NI; n = 8). We assessed respiratory, hemodynamic and volumetric variables, including both the extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI). We measured plasma nitrite/nitrate (NOx) levels and examined lung biopsies for lung injury score (LIS). RESULTS Both the injuriously ventilated groups demonstrated a 2-3-fold rise in EVLWI and PVPI, with no significant effects of NI. In the INJV group, gas exchange deteriorated in parallel with emerging respiratory acidosis, but administration of NI antagonized the derangement of oxygenation and the respiratory acidosis significantly. NOx displayed no significant changes and NI exerted no significant effect on LIS in the INJV group. CONCLUSION Inhibition of nNOS improved gas exchange, but did not reduce lung water extravasation following injurious ventilation after pneumonectomy in sheep.
Collapse
Affiliation(s)
- Evgeny V Suborov
- Anesthesia and Critical Care Research Group, Institute of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway
| | - Alexey A Smetkin
- Anesthesia and Critical Care Research Group, Institute of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway
- Department of Anesthesiology, Northern State Medical University, Arkhangelsk, Russian Federation
| | - Timofey V Kondratiev
- Anesthesia and Critical Care Research Group, Institute of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway
| | - Andrey Y Valkov
- Department of Clinical Pathology, University Hospital of Northern Norway, 9038, Tromsø, Norway
- Institute of Medical Biology, University of Tromsø, 9037, Tromsø, Norway
| | - Vsevolod V Kuzkov
- Anesthesia and Critical Care Research Group, Institute of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway
- Department of Anesthesiology, Northern State Medical University, Arkhangelsk, Russian Federation
| | - Mikhail Y Kirov
- Anesthesia and Critical Care Research Group, Institute of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway
- Department of Anesthesiology, Northern State Medical University, Arkhangelsk, Russian Federation
| | - Lars J Bjertnaes
- Anesthesia and Critical Care Research Group, Institute of Clinical Medicine, Faculty of Health Sciences, University of Tromsø, 9037, Tromsø, Norway
| |
Collapse
|
8
|
Combined Recombinant Human Activated Protein C and Ceftazidime Prevent the Onset of Acute Respiratory Distress Syndrome in Severe Sepsis. Shock 2012; 37:170-6. [DOI: 10.1097/shk.0b013e31823ca8ee] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
9
|
Nebulized Anticoagulants Limit Coagulopathy But Not Inflammation in Pseudomonas aeruginosa-Induced Pneumonia in Rats. Shock 2011; 36:417-23. [DOI: 10.1097/shk.0b013e31822bcef0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
10
|
Maybauer MO, Maybauer DM, Fraser JF, Szabo C, Westphal M, Kiss L, Horvath EM, Nakano Y, Herndon DN, Traber LD, Traber DL. Recombinant human activated protein C attenuates cardiovascular and microcirculatory dysfunction in acute lung injury and septic shock. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:R217. [PMID: 21110850 PMCID: PMC3220026 DOI: 10.1186/cc9342] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/15/2010] [Accepted: 11/26/2010] [Indexed: 12/19/2022]
Abstract
Introduction This prospective, randomized, controlled, experimental animal study looks at the effects of recombinant human activated protein C (rhAPC) on global hemodynamics and microcirculation in ovine acute lung injury (ALI) and septic shock, resulting from smoke inhalation injury. Methods Twenty-one sheep (37 ± 2 kg) were operatively prepared for chronic study and randomly allocated to either the sham, control, or rhAPC group (n = 7 each). The control and rhAPC groups were subjected to insufflation of four sets of 12 breaths of cotton smoke followed by instillation of live Pseudomonas aeruginosa into both lung lobes, according to an established protocol. Healthy sham animals were not subjected to the injury and received only four sets of 12 breaths of room air and instillation of the vehicle (normal saline). rhAPC (24 μg/kg/hour) was intravenously administered from 1 hour post injury until the end of the 24-hour experiment. Regional microvascular blood flow was analyzed using colored microspheres. All sheep were mechanically ventilated with 100% oxygen, and fluid resuscitated with lactated Ringer's solution to maintain hematocrit at baseline levels. Results The rhAPC-associated reduction in heart malondialdehyde (MDA) and heart 3-nitrotyrosine (a reliable indicator of tissue injury) levels occurred parallel to a significant increase in mean arterial pressure and to a significant reduction in heart rate and cardiac output compared with untreated controls that showed a typical hypotensive, hyperdynamic response to the injury (P < 0.05). In addition, rhAPC significantly attenuated the changes in microvascular blood flow to the trachea, kidney, and spleen compared with untreated controls (P < 0.05 each). Blood flow to the ileum and pancreas, however, remained similar between groups. The cerebral blood flow as measured in cerebral cortex, cerebellum, thalamus, pons, and hypothalamus, was significantly increased in untreated controls, due to a loss of cerebral autoregulation in septic shock. rhAPC stabilized cerebral blood flow at baseline levels, as in the sham group. Conclusions We conclude that rhAPC stabilized cardiovascular functions and attenuated the changes in visceral and cerebral microcirculation in sheep suffering from ALI and septic shock by reduction of cardiac MDA and 3-nitrotyrosine.
Collapse
Affiliation(s)
- Marc O Maybauer
- Department of Anesthesiology, Investigational Intensive Care Unit, The University of Texas Medical Branch and Shriners Burns Hospital for Children, 301 University Blvd, Galveston, TX 77555-0591, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Stahl W, Bracht H, Radermacher P, Thomas J. Year in review 2009: Critical Care--shock. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:239. [PMID: 21122169 PMCID: PMC3220051 DOI: 10.1186/cc9261] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The research papers on shock that have been published in Critical Care throughout 2009 are related to four major subjects: first, alterations of heart function and, second, the role of the sympathetic central nervous system during sepsis; third, the impact of hemodynamic support using vasopressin or its synthetic analog terlipressin, and different types of fluid resuscitation; as well as, fourth, experimental studies on the treatment of acute respiratory distress syndrome. The present review summarizes the key results of these studies together with a brief discussion in the context of the relevant scientific and clinical background published both in this and other journals.
Collapse
Affiliation(s)
- Wolfgang Stahl
- Sektion Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Klinik für Anästhesiologie, Universitätsklinikum, Parkstrasse 11, D-89073 Ulm, Germany
| | | | | | | |
Collapse
|
12
|
LaRosa SP. Activated protein C for H1N1 influenza? More work to do! CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:156. [PMID: 20497609 PMCID: PMC2911698 DOI: 10.1186/cc8994] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An animal model of H1N1 influenza demonstrates that this infection is associated with pulmonary and systemic activation of coagulation and impairment of fibrinolysis in addition to systemic inflammation and intense neutrophil influx into the lung. Activated protein C attenuates coagulation activation and restores fibrinolytic capacity but has little effect on inflammation or survival from this infection. This animal model points to a profound inflammatory state developing in H1N1 infection that impacts mortality. Additional modifications to the model and the type and amount of activated protein C dosing will provide the data to determine the possible use of activated protein C as a therapy in human H1N1 infection.
Collapse
Affiliation(s)
- Steven P LaRosa
- Division of Infectious Disease, Rhode Island Hospital, Alpert School of Medicine, Brown University, 593 Eddy Street, Providence, RI 02903, USA.
| |
Collapse
|
13
|
Nonventilatory strategies for patients with life-threatening 2009 H1N1 influenza and severe respiratory failure. Crit Care Med 2010; 38:e74-90. [PMID: 20035216 DOI: 10.1097/ccm.0b013e3181cc5373] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Severe respiratory failure (including acute lung injury and acute respiratory distress syndrome) caused by 2009 H1N1 influenza infection has been reported worldwide. Refractory hypoxemia is a common finding in these patients and can be challenging to manage. This review focuses on nonventilatory strategies in the advanced treatment of severe respiratory failure and refractory hypoxemia such as that seen in patients with severe acute respiratory distress syndrome attributable to 2009 H1N1 influenza. Specific modalities covered include conservative fluid management, prone positioning, inhaled nitric oxide, inhaled vasodilatory prostaglandins, and extracorporeal membrane oxygenation and life support. Pharmacologic strategies (including steroids) investigated for the treatment of severe respiratory failure are also reviewed.
Collapse
|
14
|
Inhaled activated protein C: a novel therapy for acute lung injury? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:150. [PMID: 19519935 PMCID: PMC2717421 DOI: 10.1186/cc7869] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Acute lung injury (ALI) is characterized by the presence of dysregulated coagulation and inflammation. Therefore, Waerhaug and colleagues hypothesized that administration of activated protein C (APC) via the inhaled route would be a novel and effective treatment for ALI. They demonstrated that inhaled APC improved oxygenation and lung aeration in a sheep model of lipopolysaccharide-induced ALI, but did not alter lung water or hemodynamics. Future studies are needed to determine plasma and airspace APC levels when administered by the inhaled route, and to determine if inhaled APC has a similar effect in other models of ALI.
Collapse
|
15
|
Waerhaug K, Kuzkov VV, Kuklin VN, Mortensen R, Nordhus KC, Kirov MY, Bjertnaes LJ. Inhaled aerosolised recombinant human activated protein C ameliorates endotoxin-induced lung injury in anaesthetised sheep. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:R51. [PMID: 19356243 PMCID: PMC2689497 DOI: 10.1186/cc7777] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 04/02/2009] [Accepted: 04/08/2009] [Indexed: 01/06/2023]
Abstract
Introduction We recently demonstrated that intravenously infused recombinant human activated protein C (APC) attenuates ovine lipopolysaccharide (LPS)-induced lung injury. In this study, our aim was to find out whether treatment with inhaled aerosolised APC (inhAPC) prevents formation of increased lung densities and oedema and derangement of oxygenation during exposure to LPS. Methods Sheep were anaesthetised during placement of intravascular introducers. After one to four days of recovery from instrumentation, the animals were re-anaesthetised, endotracheally intubated and mechanically ventilated throughout a six-hour experiment where the sheep underwent quantitative lung computed tomography. Sheep were randomly assigned to one of three groups: a sham-operated group (n = 8) receiving inhaled aerosolised saline from two hours after the start of the experiment; a LPS group (n = 8) receiving an intravenous infusion of LPS 20 ng/kg per hour and, after two hours, inhaled aerosolised saline over the next four hours; a LPS+inhAPC group (n = 8) receiving an intravenous infusion of LPS 20 ng/kg per hour and, after two hours, aerosolised APC 48 μg/kg per hour inhaled throughout the experiment. Data were analysed with analysis of variance; P less than 0.05 was regarded as significant. Results An infusion of LPS was associated with a reduction of well-aerated lung volume and a rapid fall in arterial oxygenation that were both significantly antagonised by inhaled APC. Pulmonary vascular pressures and extravascular lung water index increased significantly during exposure to LPS, but inhaled APC had no effect on these changes. Conclusions Inhalation of aerosolised APC attenuates LPS-induced lung injury in sheep by preventing a decline in the volume of aerated lung tissue and improving oxygenation.
Collapse
Affiliation(s)
- Kristine Waerhaug
- Department of Anesthesiology, Institute of Clinical Medicine, Faculty of Medicine, University of Tromsø, N-9037 Tromsø, Norway
| | | | | | | | | | | | | |
Collapse
|
16
|
Recombinant human activated protein C in acute lung injury: what is the role of bronchial circulation? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:112. [PMID: 19226431 PMCID: PMC2688104 DOI: 10.1186/cc7155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Impairment of the protein C pathway plays a central role in the pathogenesis of sepsis. Treatment with recombinant human activated protein C (rhAPC) has been reported to increase survival from severe sepsis. Protein C levels also decrease markedly in acute lung injury, of both septic and nonseptic origin. Low levels of protein C in acute lung injury are associated with poor clinical outcome. The present article discusses the beneficial effects of rhAPC in oleic acid-induced lung injury as well as the controversies between different animal models and the timing of drug administration. The unique bronchial circulation in ovine models seems to be responsible for the beneficial effects of rhAPC when given simultaneously to the injury.
Collapse
|
17
|
Recombinant human activated protein C ameliorates oleic acid-induced lung injury in awake sheep. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:R146. [PMID: 19021914 PMCID: PMC2646309 DOI: 10.1186/cc7128] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 11/07/2008] [Accepted: 11/20/2008] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Acute lung injury (ALI) may arise both after sepsis and non-septic inflammatory conditions and is often associated with the release of fatty acids, including oleic acid (OA). Infusion of OA has been used extensively to mimic ALI. Recent research has revealed that intravenously administered recombinant human activated protein C (rhAPC) is able to counteract ALI. Our aim was to find out whether rhAPC dampens OA-induced ALI in sheep. METHODS Twenty-two yearling sheep underwent instrumentation. After 2 days of recovery, animals were randomly assigned to one of three groups: (a) an OA+rhAPC group (n = 8) receiving OA 0.06 mL/kg infused over the course of 30 minutes in parallel with an intravenous infusion of rhAPC 24 mg/kg per hour over the course of 2 hours, (b) an OA group (n = 8) receiving OA as above, or (c) a sham-operated group (n = 6). After 2 hours, sheep were sacrificed. Hemodynamics was assessed by catheters in the pulmonary artery and the aorta, and extravascular lung water index (EVLWI) was determined with the single transpulmonary thermodilution technique. Gas exchange was evaluated at baseline and at cessation of the experiment. Data were analyzed by analysis of variance; a P value of less than 0.05 was regarded as statistically significant. RESULTS OA induced profound hypoxemia, increased right atrial and pulmonary artery pressures and EVLWI markedly, and decreased cardiac index. rhAPC counteracted the OA-induced changes in EVLWI and arterial oxygenation and reduced the OA-induced increments in right atrial and pulmonary artery pressures. CONCLUSIONS In ovine OA-induced lung injury, rhAPC dampens the increase in pulmonary artery pressure and counteracts the development of lung edema and the derangement of arterial oxygenation.
Collapse
|
18
|
Rehberg S, Enkhbaatar P, Traber DL. Anticoagulant therapy in acute lung injury: a useful tool without proper operating instruction? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:179. [PMID: 18828885 PMCID: PMC2592737 DOI: 10.1186/cc7002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Activation of the coagulation cascade resulting in alveolar fibrin deposition is recognized as a hallmark of acute lung injury (ALI). Anticoagulant treatment with recombinant human activated protein C (rhAPC) appears promising, because – like in sepsis – there is a deficiency of protein C in ALI, which is correlated with poor outcome in both syndromes. Recently in Critical Care, Waerhaug and colleagues confirmed the beneficial effects of rhAPC on pulmonary function in ovine endotoxin-induced ALI. Notably, the authors reported no differences in hemorrhage in histologic analyses between rhAPC-treated and untreated animals. However, a recently reported randomized, placebo-controlled, multicenter trial in ALI patients without severe sepsis failed to identify any differences in the number of ventilator-free days or 60 day-mortality between the rhAPC and placebo group. In addition to (or perhaps because of) the complex pathogenesis, the discrepancy between clinical and experimental results in ALI is another common feature with sepsis. The future challenge will be to transfer our theoretical knowledge adequately into daily clinical practice. Anticoagulant therapy might be a useful tool in the treatment of ALI; however the proper operating instruction remains to be defined.
Collapse
Affiliation(s)
- Sebastian Rehberg
- Department of Anesthesiology, The University of Texas Medical Branch, 301 University Blvd, 77555 Galveston, TX, USA.
| | | | | |
Collapse
|