scholarly journals Pentoxifylline attenuation of experimental hepatopulmonary syndrome

2007 ◽  
Vol 102 (3) ◽  
pp. 949-955 ◽  
Author(s):  
Junlan Zhang ◽  
Yiqun Ling ◽  
Liping Tang ◽  
Bao Luo ◽  
Balu K. Chacko ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Shear Stress ◽  
Hepatopulmonary Syndrome ◽  
Microvascular Endothelial Cells ◽  
Enos Expression ◽  
Akt Activation ◽  
Pulmonary Microvascular Endothelial Cells ◽  
Tnf Α

Hepatopulmonary syndrome (HPS) following rat common bile duct ligation results from pulmonary molecular changes that may be influenced by circulating TNF-α and increased vascular shear stress, through activation of NF-κB or Akt. Increased pulmonary microvascular endothelin B (ETB) receptor and endothelial nitric oxide synthase (eNOS) levels contribute to nitric oxide production and the development of experimental HPS. Pentoxifylline (PTX), a phosphodiesterase and nonspecific TNF-α inhibitor, ameliorates experimental HPS when begun before hepatic injury. However, how PTX influences the molecular events associated with initiation of experimental HPS after liver injury is established is unknown. We assessed the effects of PTX on the molecular and physiological features of HPS in vivo and on shear stress or TNF-α-mediated events in rat pulmonary microvascular endothelial cells in vitro. PTX significantly improved HPS without altering portal or systemic hemodynamics and downregulated pulmonary ETB receptor levels and eNOS expression and activation. These changes were associated with a reduction in circulating TNF levels and NF-κB activation and complete inhibition of Akt activation. In rat pulmonary microvascular endothelial cells, PTX inhibited shear stress-induced ETB receptor and eNOS expression and eNOS activation. These effects were also associated with inhibition of Akt activation and were reproduced by wortmanin. In contrast, TNF-α had no effects on endothelial ETB and eNOS alterations in vitro. PTX has direct effects in the pulmonary microvasculature, likely mediated through Akt inhibition, that ameliorate experimental HPS.

Role of NF-κB and PI 3-kinase/Akt in TNF-α-induced cytotoxicity in microvascular endothelial cells

2008 ◽  
Vol 295 (4) ◽  
pp. F932-F941 ◽  
Author(s):  
Zhu Zhou ◽  
Patricia Gengaro ◽  
Wei Wang ◽  
Xue-qing Wang ◽  
Chunling Li ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Kinase Inhibitor ◽  
Pi3 Kinase ◽  
Microvascular Endothelial Cells ◽  
Pyrrolidine Dithiocarbamate ◽  
Apoptotic Pathway ◽  
Akt Activation ◽  
Tnf Α ◽  
Microvascular Endothelial

The interaction of tumor necrosis factor (TNF)-α with the endothelium is a pivotal factor during endotoxemia. Inflammatory conditions are characterized by the activation of the transcription factor NF-κB and the expression of inflammatory mediators. Previous reports indicate that inhibition of NF-κB activation during sepsis may be beneficial to the microvasculature. In addition, the phosphatidylinositol-3-kinase/Akt signaling pathway (PI3-kinase/Akt) has been shown to be cytoprotective. In this study, we examined the effect of inhibition of NF-κB and PI3-kinase/Akt on cell viability, cytokine production, inducible nitric oxide synthase (iNOS) expression, and nitric oxide (NO) generation by TNF-α-treated cultured microvascular endothelial cells. TNF-α induced significant cytotoxicity and was associated with increased inflammatory cytokines and NO and increased expression of iNOS. The NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), prevented these increases and significantly attenuated the TNF-α-induced cytotoxicity. TNF-α also caused PI3-kinase/Akt activation, which was further increased by PDTC and prevented by the PI3-kinase inhibitor, LY294002. Inhibition of PI3-kinase/Akt also significantly potentiated TNF-α-mediated cytotoxicity. LY294002 treatment resulted in the appearance of increased apoptosis, compatible with the known anti-apoptotic properties of PI3-kinase/Akt. The present results therefore demonstrate a cytotoxic effect of TNF-α in microvascular endothelial cells which can be attenuated by NF-κB inhibition. In addition, PI3-kinase/Akt activation during TNF-α exposure may represent a compensatory anti-necrotic and anti-apoptotic pathway. The cytoprotective effects of NF-κB inhibition and PI3-kinase/Akt activation may have potential implications in the treatment of endotoxemia and septic shock.

Abstract 474: Effects of Cigarette Smoke on CD146 Expression and Function in Pulmonary Endothelial Cells

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Adelheid Kratzer ◽  
Jonas Salys ◽  
Benjy Gonzalez ◽  
Hong Wei Chu ◽  
Martin Zamora ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cigarette Smoke ◽  
Immunofluorescent Staining ◽  
Microvascular Endothelial Cells ◽  
Pulmonary Microvascular Endothelial Cells ◽  
Pulmonary Endothelial Cells ◽  
Membrane Bound ◽  
Microvascular Endothelial ◽  
Cd146 Expression

Background and Objectives: Cell adhesion molecule CD146 is a transmembrane glycoprotein constitutively expressed in all types of endothelial cells (EC). It exists in two forms: a membrane-anchored form (CD146) and a soluble, extracellular and cleaved form (sCD146). The plasma concentration of sCD146 is modulated in inflammatory diseases that involve endothelial alterations. We investigated the role of endothelial CD146 in cigarette smoke-induced emphysema in vivo and in pulmonary endothelial cells (EC) in vitro . Methods: Sprague Dawley rats exposed to cigarette smoke for 2 months developed significant emphysematous changes (measured by mean linear intercept). Levels of sCD146 were subsequently measured in the circulation as well as in the bronchoalveolar lavage fluid (BALf) via ELISA. In vitro studies were carried out in rat pulmonary microvascular endothelial cells using CSE. Results: CD146 is highly expressed in rat pulmonary microvascular endothelial cells (RPMVEC) and to a much lower extent, in pulmonary macrovascular endothelial cells (RPAEC). Treatment of RPMVEC with cigarette smoke extract (CSE) in vitro resulted in decreased expression of membrane-bound CD146 as well as a reduced gene expression and increased sCD146 levels in the culture medium after 12 hours. Moreover, CSE-induced downregulation of CD146 expression resulted in increased vascular permeability of RPMVEC, as measured by EVANs Blue assay and migration of CFSE-labeled rat alveolar macrophage. Immunofluorescent staining revealed that CSE treatment resulted in translocation of membrane-bound CD146 into the nucleus. Subsequent western blot analysis showed changes in ERK and AKT activation and signaling. Similar results were found upon siRNA silencing of CD146, implicating a role for CD146 in tissue inflammation and integrity. Circulating levels of sCD146 were also elevated in plasma and BALf of patients with COPD and correlated, in part, with the presence of anti-endothelial autoantibodies. Additionally, we found decreased expression of membrane-bound CD146 in lung tissues of COPD patients. Conclusions: Our data suggest that CD146 plays an important role in pulmonary vascular EC function. Moreover, levels of circulating soluble CD146 can be a predictor of vascular endothelial cell injury.

Shear stress increases expression of a KATP channel in rat and bovine pulmonary vascular endothelial cells

2003 ◽  
Vol 285 (4) ◽  
pp. C959-C967 ◽  
Author(s):  
Shampa Chatterjee ◽  
Abu-Bakr Al-Mehdi ◽  
Irena Levitan ◽  
Troy Stevens ◽  
Aron B. Fisher
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Membrane Depolarization ◽  
Microvascular Endothelial Cells ◽  
Adaptation Period ◽  
Pulmonary Microvascular Endothelial Cells ◽  
Channel Expression ◽  
Microvascular Endothelial ◽  
Flow Adaptation ◽  
Expression And Activity

We have shown previously that acute ischemia leads to depolarization of pulmonary microvascular endothelial cells that is prevented with cromakalim, suggesting the presence of ATP-sensitive K+ (KATP) channels in these cells. Thus KATP channel expression and activity were evaluated in rat pulmonary microvascular endothelial cells (RPMVEC) by whole cell current measurements, dot blot (mRNA), and immunoblot (protein) for the inwardly rectifying K+ channel (KIR) 6.2 subunit and fluorescent ligand binding for the sulfonylurea receptor (SUR). Low-level expression of a KATP channel was detected in endothelial cells in routine (static) culture and led us to examine whether its expression is inducible when endothelial cells are adapted to flow. Channel expression (mRNA and both KIR6.2 and SUR proteins) and inwardly rectified membrane current by patch clamp increased significantly when RPMVEC were adapted to flow at 10 dyn/cm2 for 24 h in either a parallel plate flow chamber or an artificial capillary system. Induction of the KATP channel with flow adaptation was also observed in bovine pulmonary artery endothelial cells. Flow-adapted but not static RPMVEC showed cellular plasma membrane depolarization upon stop of flow that was inhibited by a KATP channel opener and prevented by addition of cycloheximide to the medium during the flow adaptation period. These studies indicate the induction of KATP channels by flow adaptation in pulmonary endothelium and that the expression and activity of this channel are essential for the endothelial cell membrane depolarization response with acute decrease in shear stress.

scholarly journals Donor antibodies to HNA-3a implicated in TRALI reactions prime neutrophils and cause PMN-mediated damage to human pulmonary microvascular endothelial cells in a two-event in vitro model

Blood ◽  
2006 ◽  
Vol 109 (4) ◽  
pp. 1752-1755 ◽  
Author(s):  
Christopher C. Silliman ◽  
Brian R. Curtis ◽  
Patricia M. Kopko ◽  
Samina Y. Khan ◽  
Marguerite R. Kelher ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
In Vitro Model ◽  
Microvascular Endothelial Cells ◽  
Pulmonary Microvascular Endothelial Cells ◽  
Biologic Response ◽  
Event Model ◽  
Microvascular Endothelial ◽  
Vitro Model ◽  
Related Mortality

Abstract Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. Antibodies to HNA-3a are commonly implicated in TRALI. We hypothesized that HNA-3a antibodies prime neutrophils (PMNs) and cause PMN-mediated cytotoxicity through a two-event pathogenesis. Isolated HNA-3a+ or HNA-3a− PMNs were incubated with plasma containing HNA-3a antibodies implicated in TRALI, and their ability to prime the oxidase was measured. Human pulmonary microvascular endothelial cells (HMVECs) were activated with endotoxin or buffer, HNA-3a+ or HNA-3a− PMNs were added, and the coculture was incubated with plasma ± antibodies to HNA-3a. PMN-mediated damage was measured by counting viable HMVECs/mm2. Plasma containing HNA-3a antibodies primed the fMLP-activated respiratory burst of HNA-3a+, but not HNA-3a−, PMNs and elicited PMN-mediated damage of LPS-activated HMVECs when HNA-3a+, but not HNA-3a−, PMNs were used. Thus, antibodies to HNA-3a primed PMNs and caused PMN-mediated HMVEC cytotoxicity in a two-event model identical to biologic response modifiers implicated in TRALI.

scholarly journals Endothelial Nitric Oxide Synthase Expression Is Progressively Increased in Primary Cerebral Microvascular Endothelial Cells During Hyperbaric Oxygen Exposure

2009 ◽  
Vol 2 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Xiongfei Xu ◽  
Zhongzhuang Wang ◽  
Quan Li ◽  
Xiang Xiao ◽  
Qinglin Lian ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Hyperbaric Oxygen ◽  
Endothelial Nitric Oxide Synthase ◽  
Microvascular Endothelial Cells ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide ◽  
Enos Protein

Exposure to hyperbaric oxygen (HBO) can lead to seizures. Many studies have demonstrated that there exist a very close relationship between the alteration of cerebral blood flow (CBF) and the onset of seizures. Nitric oxide (NO) may play a key role in the change of CBF during exposure, and modulation of endothelial nitric oxide synthase (eNOS)-derived NO by HBO is responsible for early vasoconstriction, whereas late HBO-induced vasodilation depends upon a large amount of NO from both eNOS and neuronal nitric oxide synthase (nNOS). To investigate the effect of HBO on the activity and expression of eNOS in cerebral microvascular endothelial cells (CMEC) in vitro, primarily cultured CMEC from neonatal rats were exposed to oxygen at 500 kPa [5 atmosphere absolute (ATA)] for 10, 20, 30, 60 and 120 minutes (min), then eNOS activity, protein and mRNA contents in cells were detected. Our results showed that immediately after exposure, 30, 60 and 120 min HBO exposures did not alter NOS activity. When detected no matter immediately or six hours (h) after exposure, these exposures also did not alter eNOS protein and mRNA levels. However, when detected 24 h after exposure, 30, 60 and 120 min exposures upregulated eNOS protein content by 39%, 60% and 40% respectively. 10 and 20 min exposures upregulated eNOS mRNA content by about 15%, while 30, 60 and 120 min exposures upregulated it by about 20–30%. The increased eNOS protein and mRNA contents at 24 h after exposure may reflect new protein synthesis for eNOS. Our studies showed that with the exposing protocols we used, HBO did induce eNOS expression increase in CMEC. However, compared with the decrease of CBF in vivo, which occurred in a relative short time after rat was exposed to HBO above 4 ATA, the responses of eNOS in CMEC in vitro were a little slow. Thus we considered that for the vasodilation in the late period of HBO exposure before seizure, the effect of NO produced by eNOS was limited.

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