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Normal Saline solutions cause endothelial dysfunction through loss of membrane integrity, ATP release, and inflammatory responses mediated by P2X7R/p38 MAPK/MK2 signaling pathways. PLoS One 2019; 14:e0220893. [PMID: 31412063 PMCID: PMC6693757 DOI: 10.1371/journal.pone.0220893] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/25/2019] [Indexed: 12/12/2022] Open
Abstract
Resuscitation with 0.9% Normal Saline (NS), a non-buffered acidic solution, leads to increased morbidity and mortality in the critically ill. The goal of this study was to determine the molecular mechanisms of endothelial injury after exposure to NS. The hypothesis of this investigation is that exposure of endothelium to NS would lead to loss of cell membrane integrity, resulting in release of ATP, activation of the purinergic receptor (P2X7R), and subsequent activation of stress activated signaling pathways and inflammation. Human saphenous vein endothelial cells (HSVEC) incubated in NS, but not buffered electrolyte solution (Plasma-Lyte, PL), exhibited abnormal morphology and increased release of lactate dehydrogenase (LDH), adenosine triphosphate (ATP), and decreased transendothelial resistance (TEER), suggesting loss of membrane integrity. Incubation of intact rat aorta (RA) or human saphenous vein in NS but not PL led to impaired endothelial-dependent relaxation which was ameliorated by apyrase (hydrolyzes ATP) or SB203580 (p38 MAPK inhibitor). Exposure of HSVEC to NS but not PL led to activation of p38 MAPK and its downstream substrate, MAPKAP kinase 2 (MK2). Treatment of HSVEC with exogenous ATP led to interleukin 1β (IL-1β) release and increased vascular cell adhesion molecule (VCAM) expression. Treatment of RA with IL-1β led to impaired endothelial relaxation. IL-1β treatment of HSVEC led to increases in p38 MAPK and MK2 phosphorylation, and increased levels of arginase II. Incubation of porcine saphenous vein (PSV) in PL with pH adjusted to 6.0 or less also led to impaired endothelial function, suggesting that the acidic nature of NS is what contributes to endothelial dysfunction. Volume overload resuscitation in a porcine model after hemorrhage with NS, but not PL, led to acidosis and impaired endothelial function. These data suggest that endothelial dysfunction caused by exposure to acidic, non-buffered NS is associated with loss of membrane integrity, release of ATP, and is modulated by P2X7R-mediated inflammatory responses.
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Komalavilas P, Luo W, Guth CM, Jolayemi O, Bartelson RI, Cheung-Flynn J, Brophy CM. Vascular surgical stretch injury leads to activation of P2X7 receptors and impaired endothelial function. PLoS One 2017; 12:e0188069. [PMID: 29136654 PMCID: PMC5685620 DOI: 10.1371/journal.pone.0188069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/31/2017] [Indexed: 12/17/2022] Open
Abstract
A viable vascular endothelial layer prevents vasomotor dysfunction, thrombosis, inflammation, and intimal hyperplasia. Injury to the endothelium occurs during harvest and “back table” preparation of human saphenous vein prior to implantation as an arterial bypass conduit. A subfailure overstretch model of rat aorta was used to show that subfailure stretch injury of vascular tissue leads to impaired endothelial-dependent relaxation. Stretch-induced impaired relaxation was mitigated by treatment with purinergic P2X7 receptor (P2X7R) inhibitors, brilliant blue FCF (FCF) and A740003, or apyrase, an enzyme that catalyzes the hydrolysis of ATP. Alternatively, treatment of rat aorta with exogenous ATP or 2’(3’)-O-(4-Benzoyl benzoyl)-ATP (BzATP) also impaired endothelial-dependent relaxation. Treatment of human saphenous vein endothelial cells (HSVEC) with exogenous ATP led to reduced nitric oxide production which was associated with increased phosphorylation of the stress activated protein kinase, p38 MAPK. ATP- stimulated p38 MAPK phosphorylation of HSVEC was inhibited by FCF and SB203580. Moreover, ATP inhibition of nitric oxide production in HSVEC was prevented by FCF, SB203580, L-arginine supplementation and arginase inhibition. Finally, L-arginine supplementation and arginase inhibition restored endothelial dependent relaxation after stretch injury of rat aorta. These results suggest that vascular stretch injury leads to ATP release, activation of P2X7R and p38 MAPK resulting in endothelial dysfunction due to arginase activation. Endothelial function can be restored in both ATP treated HSVEC and intact stretch injured rat aorta by P2X7 receptor inhibition with FCF or L-arginine supplementation, implicating straightforward therapeutic options for treatment of surgical vascular injury.
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Affiliation(s)
- Padmini Komalavilas
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
- VA Tennessee Valley Healthcare System, Nashville, TN, United States of America
- * E-mail:
| | - Weifeng Luo
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
| | - Christy M. Guth
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
| | - Olukemi Jolayemi
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
| | - Rachel I. Bartelson
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
| | - Joyce Cheung-Flynn
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
| | - Colleen M. Brophy
- Vanderbilt University Medical Center, Department of Surgery, Nashville, TN, United States of America
- VA Tennessee Valley Healthcare System, Nashville, TN, United States of America
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Guth CM, Luo W, Jolayemi O, Chadalavada KS, Komalavilas P, Cheung-Flynn J, Brophy CM. Adenosine triphosphate as a molecular mediator of the vascular response to injury. J Surg Res 2017; 216:80-86. [PMID: 28807217 DOI: 10.1016/j.jss.2017.03.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/03/2017] [Accepted: 03/23/2017] [Indexed: 11/29/2022]
Abstract
BACKGROUND Human saphenous veins used for arterial bypass undergo stretch injury at the time of harvest and preimplant preparation. Vascular injury promotes intimal hyperplasia, the leading cause of graft failure, but the molecular events leading to this response are largely unknown. This study investigated adenosine triphosphate (ATP) as a potential molecular mediator in the vascular response to stretch injury, and the downstream effects of the purinergic receptor, P2X7R, and p38 MAPK activation. MATERIALS AND METHODS A subfailure stretch rat aorta model was used to determine the effect of stretch injury on release of ATP and vasomotor responses. Stretch-injured tissues were treated with apyrase, the P2X7R antagonist, A438079, or the p38 MAPK inhibitor, SB203580, and subsequent contractile forces were measured using a muscle bath. An exogenous ATP (eATP) injury model was developed and the experiment repeated. Change in p38 MAPK phosphorylation after stretch and eATP tissue injury was determined using Western blotting. Noninjured tissue was incubated in the p38 MAPK activator, anisomycin, and subsequent contractile function and p38 MAPK phosphorylation were analyzed. RESULTS Stretch injury was associated with release of ATP. Contractile function was decreased in tissue subjected to subfailure stretch, eATP, and anisomycin. Contractile function was restored by apyrase, P2X7R antagonism, and p38-MAPK inhibition. Stretch, eATP, and anisomycin-injured tissue demonstrated increased phosphorylation of p38 MAPK. CONCLUSIONS Taken together, these data suggest that the vascular response to stretch injury is associated with release of ATP and activation of the P2X7R/P38 MAPK pathway, resulting in contractile dysfunction. Modulation of this pathway in vein grafts after harvest and before implantation may reduce the vascular response to injury.
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Affiliation(s)
- Christy M Guth
- Department of Surgery, Vanderbilt University, Nashville, Tennessee.
| | - Weifung Luo
- Department of Surgery, Vanderbilt University, Nashville, Tennessee
| | - Olukemi Jolayemi
- Department of Surgery, Vanderbilt University, Nashville, Tennessee
| | | | | | | | - Colleen M Brophy
- Department of Surgery, Vanderbilt University, Nashville, Tennessee; VA Tennessee Valley Healthcare System, Nashville, Tennessee
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Luo W, Guth CM, Jolayemi O, Duvall CL, Brophy CM, Cheung-Flynn J. Subfailure Overstretch Injury Leads to Reversible Functional Impairment and Purinergic P2X7 Receptor Activation in Intact Vascular Tissue. Front Bioeng Biotechnol 2016; 4:75. [PMID: 27747211 PMCID: PMC5040722 DOI: 10.3389/fbioe.2016.00075] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 09/13/2016] [Indexed: 11/30/2022] Open
Abstract
Vascular stretch injury is associated with blunt trauma, vascular surgical procedures, and harvest of human saphenous vein for use in vascular bypass grafting. A model of subfailure overstretch in rat abdominal aorta was developed to characterize surgical vascular stretch injury. Longitudinal stretch of rat aorta was characterized ex vivo. Stretch to the haptic endpoint, where the tissues would no longer lengthen, occurred at twice the resting length. The stress produced at this length was greater than physiologic mechanical forces but well below the level of mechanical disruption. Functional responses were determined in a muscle bath, and this subfailure overstretch injury led to impaired smooth muscle function that was partially reversed by treatment with purinergic receptor (P2X7R) antagonists. These data suggest that vasomotor dysfunction caused by subfailure overstretch injury may be due to the activation of P2X7R. These studies have implications for our understanding of mechanical stretch injury of blood vessels and offer novel therapeutic opportunities.
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Affiliation(s)
- Weifeng Luo
- Department of Surgery, Vanderbilt University, Nashville, TN, USA
| | - Christy M. Guth
- Department of Surgery, Vanderbilt University, Nashville, TN, USA
| | - Olukemi Jolayemi
- Department of Surgery, Vanderbilt University, Nashville, TN, USA
| | - Craig L. Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Colleen Marie Brophy
- Department of Surgery, Vanderbilt University, Nashville, TN, USA
- VA Tennessee Valley Healthcare System, Nashville, TN, USA
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Barabási B, Csondor A, Martín-Pozas T, Pulupa Sánchez A, Antalffy G, Siklós L, Gómez-Pinedo U, Párducz Á, Hoyk Z. Effect of axotomy and 17β-estradiol on P2X7 receptor expression pattern in the hypoglossal nucleus of ovariectomized mice. Neuroscience 2016; 319:107-15. [DOI: 10.1016/j.neuroscience.2016.01.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/19/2016] [Accepted: 01/22/2016] [Indexed: 12/18/2022]
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Madec S, Rossi C, Chiarugi M, Santini E, Salvati A, Ferrannini E, Solini A. Adipocyte P2X7 receptors expression: a role in modulating inflammatory response in subjects with metabolic syndrome? Atherosclerosis 2011; 219:552-8. [PMID: 21978920 DOI: 10.1016/j.atherosclerosis.2011.09.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 09/08/2011] [Accepted: 09/10/2011] [Indexed: 12/24/2022]
Abstract
OBJECTIVE P2X(7) receptor (P2X(7)R), upon its stimulation with extracellular ATP, modulates several inflammatory responses in different cell types. No information is available on its presence in human adipocytes and its potential involvement in the chronic inflammation associated with metabolic syndrome (MS). Therefore, we evaluated P2X(7)R presence and functional activity in adipocytes from visceral (VAT) and subcutaneous (SAT) adipose tissue of patients with MS and controls (CTL). METHODS Adipocyte gene expression of TNFα, IL-6 and PAI-1 (by realtime-PCR) and their plasma concentrations (ELISA); P2X(7)R expression (realtime-PCR, Western blot and immunofluorescence); P2X(7)R functional activity (intracellular calcium fluxes by fluorimetry); cytokine release from adipocytes (ELISA). The inflammasome components were also determined. RESULTS In VAT, TNFα, IL-6 and PAI-1 were more expressed in MS than in CTL. These differences were confirmed in SAT for IL-6 and PAI-1. Plasma IL-6, PAI-1 and TNFα levels were higher in MS. P2X(7)R mRNA and protein, identified in both VAT and SAT, were more abundant in MS than in CTL. Immunofluoresce confirmed the typical "ring-like" arrangement of P2X(7)R at the plasma membrane. Benzoyl-benzoyl-ATP raised intracellular calcium both in VAT and SAT, and induced IL-6, TNFα and PAI-1 release in both MS and CTL cells. This effect was partially inhibited by KN62, specific human P2X(7)R blocker, or by P2X(7)R gene silencing. The inflammasome was more activated in MS than in CTL adipocytes. CONCLUSION Human adipocytes express functionally active P2X(7)R, which modulate the release of inflammatory cytokines, at least in part via inflammasome activation. Adipocytes from MS patients show an enhanced P2X(7)R expression, which might contribute to the subclinical inflammatory status characterizing these patients and conferring them an increased CV risk.
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Abstract
Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed "resting microglia." Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the "activated microglial cell." This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.
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