ENDOTHELIAL-DEPENDENT VASCULAR REACTIVITY AFTER CARDIOPULMONARY BYPASS IS ASSOCIATED WITH UNIQUE METABOLOMIC SIGNATURES.

Cardiopulmonary bypass (CPB), an extracorporeal method necessary for the surgical correction of complex congenital heart defects, incites significant inflammation that affects vascular function. These changes are associated with alterations in cellular metabolism that promote energy production to deal with this stress. Utilizing laser Doppler perfusion monitoring coupled with iontophoresis in patients undergoing corrective heart surgery, we hypothesized that temporal, untargeted metabolomics could be performed to assess the link between metabolism and vascular function.

Vascular Inflammation and Smooth Muscle Contractility: The Role of Nox1-Derived Superoxide and LRRC8 Anion Channels.

Vascular inflammation underlies the development of hypertension, and the mechanisms by which it increases blood pressure remain the topic of intense investigation. Proinflammatory factors including glucose, salt, vasoconstrictors, cytokines, wall stress, and growth factors enhance contractility and impair relaxation of vascular smooth muscle cells. These pathways share a dependence upon redox signaling, and excessive activation promotes oxidative stress that promotes vascular aging.

Extracellular SOD modulates canonical TNFα signaling and α5β1 integrin transactivation in vascular smooth muscle cells.

TNFα activates NADPH oxidase 1 (Nox1) in vascular smooth muscle cells (VSMCs). The extracellular superoxide anion (O) produced is essential for the pro-inflammatory effects of the cytokine but the specific contributions of O to signal transduction remain obscure. Extracellular superoxide dismutase (ecSOD, SOD3 gene) is a secreted protein that binds to cell surface heparin sulfate proteoglycans or to Fibulin-5 (Fib-5, FBLN5 gene), an extracellular matrix protein that also associates with elastin and integrins.

LRRC8A anion channels modulate vascular reactivity via association with myosin phosphatase rho interacting protein.

Leucine-rich repeat containing 8A (LRRC8A) volume regulated anion channels (VRACs) are activated by inflammatory and pro-contractile stimuli including tumor necrosis factor alpha (TNFα), angiotensin II and stretch. LRRC8A associates with NADPH oxidase 1 (Nox1) and supports extracellular superoxide production. We tested the hypothesis that VRACs modulate TNFα signaling and vasomotor function in mice lacking LRRC8A exclusively in vascular smooth muscle cells (VSMCs, Sm22α-Cre, Knockout).

LRRC8A anion channels modulate vasodilation via association with Myosin Phosphatase Rho Interacting Protein (MPRIP).

Background: In vascular smooth muscle cells (VSMCs), LRRC8A volume regulated anion channels (VRACs) are activated by inflammatory and pro-contractile stimuli including tumor necrosis factor alpha (TNFα), angiotensin II and stretch. LRRC8A physically associates with NADPH oxidase 1 (Nox1) and supports its production of extracellular superoxide (O ).

Methods And Results: Mice lacking LRRC8A exclusively in VSMCs (Sm22α-Cre, KO) were used to assess the role of VRACs in TNFα signaling and vasomotor function.

Chloride Channel-3 (ClC-3) Modifies the Trafficking of Leucine-Rich Repeat-Containing 8A (LRRC8A) Anion Channels.

Chloride channel-3 (ClC-3) Cl/H antiporters and leucine-rich repeat-containing 8 (LRRC8) family anion channels have both been associated with volume-regulated anion currents (VRACs). VRACs are often altered in ClC-3 null cells but are absent in LRRC8A null cells. To explore the relationship between ClC-3, LRRC8A, and VRAC we localized tagged proteins in human epithelial kidney (HEK293) cells using multimodal microscopy.

Oxidant-resistant LRRC8A/C anion channels support superoxide production by NADPH oxidase 1.

Key Points: LRRC8A-containing anion channels associate with NADPH oxidase 1 (Nox1) and regulate superoxide production and tumour necrosis factor-α (TNFα) signalling. Here we show that LRRC8C and 8D also co-immunoprecipitate with Nox1 in vascular smooth muscle cells. LRRC8C knockdown inhibited TNFα-induced O production, receptor endocytosis, nuclear factor-κB (NF-κB) activation and proliferation while LRRC8D knockdown enhanced NF-κB activation.

Apoptosis signal-regulating kinase 1 (ASK1) inhibition reduces endothelial cytokine production without improving permeability after toll-like receptor 4 (TLR4) challenge.

Sepsis represents a life-threatening event often mediated by the host's response to pathogens such as gram-negative organisms, which release the proinflammatory lipopolysaccharide (LPS). Within the endothelium, the mitogen-activated protein kinase (MAPK) pathway is an important driver of endothelial injury during sepsis, of which oxidant-sensitive apoptosis signal-regulating kinase 1 (ASK1) is postulated to be a critical upstream regulator. We hypothesized that ASK1 would play a key role in endothelial inflammation during bacterial challenge.

The Inverse Relationship Between Endothelium-Dependent Vasodilation and Blood Pressure is Lost After Cardiopulmonary Bypass.

Cardiopulmonary bypass (CPB) is required for the surgical correction of congenital heart defects and incites an acute inflammatory response that impairs endothelial function post-operatively. Therefore, we hypothesized that the pre-operative relationship between endothelial function and blood pressure would be impaired after CPB-mediated inflammation. Using laser Doppler perfusion monitoring coupled with iontophoresis, we found that while there was a significant inverse correlation between endothelium-dependent vascular reactivity to acetylcholine (ACh) stimulation and systolic blood pressure (SBP), this relationship was lost after CPB.

TNFα and Reactive Oxygen Signaling in Vascular Smooth Muscle Cells in Hypertension and Atherosclerosis.

Hypertension and atherosclerosis, the predecessors of stroke and myocardial infarction, are chronic vascular inflammatory reactions. Tumor necrosis factor alpha (TNFα), the "master" proinflammatory cytokine, contributes to both the initiation and maintenance of vascular inflammation. TNFα induces reactive oxygen species (ROS) production which drives the redox reactions that constitute "ROS signaling.

Endothelial-Dependent Vasomotor Dysfunction in Infants After Cardiopulmonary Bypass.

Objectives: Cardiopulmonary bypass-induced endothelial dysfunction has been inferred by changes in pulmonary vascular resistance, alterations in circulating biomarkers, and postoperative capillary leak. Endothelial-dependent vasomotor dysfunction of the systemic vasculature has never been quantified in this setting. The objective of the present study was to quantify acute effects of cardiopulmonary bypass on endothelial vasomotor control and attempt to correlate these effects with postoperative cytokines, tissue edema, and clinical outcomes in infants.

Apoptosis signal-regulating kinase 1 activation by Nox1-derived oxidants is required for TNFα receptor endocytosis.

Tumor necrosis factor-α (TNFα) is a proinflammatory cytokine that is closely linked to the development of cardiovascular disease. TNFα activates NADPH oxidase 1 (Nox1) and reactive oxygen species (ROS), including superoxide (O), production extracellularly is required for subsequent signaling in vascular smooth muscle cells (VSMCs). Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase that is activated by oxidation of associated thioredoxin.

Modulation of ClC-3 gating and proton/anion exchange by internal and external protons and the anion selectivity filter.

Key Points: The ClC-3 2Cl /1H exchanger modulates endosome pH and Cl concentration. We investigated the relationships between ClC-3-mediated ion transport (steady-state transport current, I ), gating charge (Q) and cytoplasmic alkalization. ClC-3 transport is functionally unidirectional.

Endothelial nitric oxide synthase modulates Toll-like receptor 4-mediated IL-6 production and permeability via nitric oxide-independent signaling.

Endothelial dysfunction, characterized by changes in eNOS, is a common finding in chronic inflammatory vascular diseases. These states are associated with increased infectious complications. We hypothesized that alterations in eNOS would enhance the response to LPS-mediated TLR4 inflammation.

LRRC8A channels support TNFα-induced superoxide production by Nox1 which is required for receptor endocytosis.

Leucine Rich Repeat Containing 8A (LRRC8A) is a required component of volume-regulated anion channels (VRACs). In vascular smooth muscle cells, tumor necrosis factor-α (TNFα) activates VRAC via type 1 TNFα receptors (TNFR1), and this requires superoxide (O) production by NADPH oxidase 1 (Nox1). VRAC inhibitors suppress the inflammatory response to TNFα by an unknown mechanism.

Potentiation and tolerance of toll-like receptor priming in human endothelial cells.

Repeated challenge of lipopolysaccharide (LPS) alters the response to subsequent LPS exposures via modulation of toll-like receptor 4 (TLR4). Whether activation of other TLRs can modulate TLR4 responses, and vice versa, remains unclear. Specifically with regards to endothelial cells, a key component of innate immunity, the impact of TLR cross-modulation is unknown.

Regulation of arterial reactivity by concurrent signaling through the E-prostanoid receptor 3 and angiotensin receptor 1.

Prostaglandin E2 (PGE2), a cyclooxygenase metabolite that generally acts as a systemic vasodepressor, has been shown to have vasopressor effects under certain physiologic conditions. Previous studies have demonstrated that PGE2 receptor signaling modulates angiotensin II (Ang II)-induced hypertension, but the interaction of these two systems in the regulation of vascular reactivity is incompletely characterized. We hypothesized that Ang II, a principal effector of the renin-angiotensin-aldosterone system, potentiates PGE2-mediated vasoconstriction.

Endothelial cell tolerance to lipopolysaccharide challenge is induced by monophosphoryl lipid A.

Prior exposure to lipopolysaccharide (LPS) produces a reduced or "tolerant" inflammatory response to subsequent challenges with LPS, however the potent pro-inflammatory effects of LPS limit its clinical benefit. The adjuvant monophosphoryl lipid A (MPLA) is a weak toll-like receptor 4 (TLR4) agonist that induces negligible inflammation but retains potent immunomodulatory properties. We postulated that pre-treatment with MPLA would inhibit the inflammatory response of endothelial cells to secondary LPS challenge.

Standardizing ICU management of pediatric traumatic brain injury is associated with improved outcomes at discharge.

OBJECT The goal of critical care in treating traumatic brain injury (TBI) is to reduce secondary brain injury by limiting cerebral ischemia and optimizing cerebral blood flow. The authors compared short-term outcomes as defined by discharge disposition and Glasgow Outcome Scale scores in children with TBI before and after the implementation of a protocol that standardized decision-making and interventions among neurosurgeons and pediatric intensivists. METHODS The authors performed a retrospective pre- and postprotocol study of 128 pediatric patients with severe TBI, as defined by Glasgow Coma Scale (GCS) scores < 8, admitted to a tertiary care center pediatric critical care unit between April 1, 2008, and May 31, 2014.

c-Jun N-terminal kinase attenuates TNFα signaling by reducing Nox1-dependent endosomal ROS production in vascular smooth muscle cells.

Tumor necrosis factor-α (TNFα), a proinflammatory cytokine, causes vascular smooth muscle cell (VSMC) proliferation and migration and promotes inflammatory vascular lesions. Nuclear factor-kappa B (NF-κB) activation by TNFα requires endosomal superoxide production by Nox1. In endothelial cells, TNFα stimulates c-Jun N-terminal kinase (JNK), which inhibits NF-κB signaling.

Pediatric posterior reversible encephalopathy syndrome presenting with isolated cerebellar edema and obstructive hydrocephalus.

In this report, the authors describe the case of a teenage boy who presented with hypertensive emergency, posterior reversible encephalopathy syndrome, and hydrocephalus due to fourth ventricle outlet obstruction. Posterior reversible encephalopathy syndrome is a well-characterized but uncommon syndrome in children that is generally triggered by severe hypertension. The unusual clinical picture of this patient, who had isolated cerebellar edema leading to obstructive hydrocephalus, has been rarely described in children.

Inhibition of endocytosis exacerbates TNF-α-induced endothelial dysfunction via enhanced JNK and p38 activation.

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine that causes endothelial dysfunction. Endocytosis of TNF-α receptors (TNFR) precedes endosomal reactive oxygen species (ROS) production, which is required for NF-κB activation in vascular smooth muscle cells. It is unknown how endocytosis of TNFRs impacts signaling in endothelial cells.

Placental HSD2 Expression and Activity Is Unaffected by Maternal Protein Consumption or Gender in C57BL/6 Mice.

The placenta acts as a physiological barrier, preventing the transfer of maternal glucocorticoids to the developing fetus. This is accomplished via the oxidation, and subsequent inactivation, of endogenous glucocorticoids by the 11- β hydroxysteroid dehydrogenase type 2 enzyme (HSD2). Maternal protein restriction during pregnancy has been shown to result in a decrease in placental HSD2 expression and fetal glucocorticoid overexposure, especially late in gestation, resulting in low birth weight and "fetal programming" of the offspring.