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Gastroesophageal reflux disease (GERD) is the retrograde flow of gastric contents into the distal esophagus and may be treated medically or surgically. Magnetic sphincter augmentation surgery using LINX has recently demonstrated comparable results to Nissen fundoplication. We aimed to evaluate preoperative patient risk factors that were associated with LINX removal rates or postoperative EGD with dilation rates (POEGDD). This is a single institution retrospective review of patients undergoing LINX between 2015 and 2021. One hundred and twelve patients were reviewed, 106 included within the study; those excluded had prior foregut surgery or device fracture. Variables including age, sex, BMI, size of device, DeMeester score, manometry, GERD Health-Related Quality of Life (GERD HRQL) questionnaires, POEGDD, and removal rates were recorded. Comparing removal and dilation status, the chi-square or Fisher’s exact test and the Mann-Whitney U test were used to analyze categorical and continuous variables, respectively. A P < .05 was considered to be statistically significant. Eleven LINX devices were removed (10%); of these, 9 (81%) underwent POEGDD ( P = .0023). There was no difference in DeMeester scores, size of device, or BMI in patients requiring LINX removal compared to those not removed or POEGDD rates. Patients who required LINX removal had higher GERD HRQL scores both preoperatively (median 34 vs 28) and postoperatively at all visits compared to those patients who did not undergo removal ( P = .032). Manometry and DeMeester scores were not associated with LINX removal suggesting a less invasive GERD HRQL questionnaire may be a better predictor of patients who will succeed with LINX surgery.

Shadab, Alam et al., We present the cosmological implications from final measurements of clustering using galaxies, quasars, and Lyα forests from the completed Sloan Digital Sky Survey (SDSS) lineage of experiments in large-scale structure. These experiments, composed of data from SDSS, SDSS-II, BOSS, and eBOSS, offer independent measurements of baryon acoustic oscillation (BAO) measurements of angular-diameter distances and Hubble distances relative to the sound horizon, rd, from eight different samples and six measurements of the growth rate parameter, fσ8, from redshift-space distortions (RSD). This composite sample is the most constraining of its kind and allows us to perform a comprehensive assessment of the cosmological model after two decades of dedicated spectroscopic observation. We show that the BAO data alone are able to rule out dark-energy-free models at more than eight standard deviations in an extension to the flat, ΛCDM model that allows for curvature. When combined with Planck Cosmic Microwave Background (CMB) measurements of temperature and polarization, under the same model, the BAO data provide nearly an order of magnitude improvement on curvature constraints relative to primary CMB constraints alone. Independent of distance measurements, the SDSS RSD data complement weak lensing measurements from the Dark Energy Survey (DES) in demonstrating a preference for a flat ΛCDM cosmological model when combined with Planck measurements. The combined BAO and RSD measurements indicate σ8=0.85±0.03, implying a growth rate that is consistent with predictions from Planck temperature and polarization data and with General Relativity. When combining the results of SDSS BAO and RSD, Planck, Pantheon Type Ia supernovae (SNe Ia), and DES weak lensing and clustering measurements, all multiple-parameter extensions remain consistent with a ΛCDM model. Regardless of cosmological model, the precision on each of the three parameters, ωΛ, H0, and σ8, remains at roughly 1%, showing changes of less than 0.6% in the central values between models. In a model that allows for free curvature and a time-evolving equation of state for dark energy, the combined samples produce a constraint ωk=-0.0022±0.0022. The dark energy constraints lead to w0=-0.909±0.081 and wa=-0.49-0.30+0.35, corresponding to an equation of state of wp=-1.018±0.032 at a pivot redshift zp=0.29 and a Dark Energy Task Force Figure of Merit of 94. The inverse distance ladder measurement under this model yields H0=68.18±0.79 km s-1 Mpc-1, remaining in tension with several direct determination methods; the BAO data allow Hubble constant estimates that are robust against the assumption of the cosmological model. In addition, the BAO data allow estimates of H0 that are independent of the CMB data, with similar central values and precision under a ΛCDM model. Our most constraining combination of data gives the upper limit on the sum of neutrino masses at mν, This paper represents an effort by both the SDSS-III and SDSS-IV collaborations. Funding for SDSS-III was provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, the Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatário Nacional/MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University.

Parkinson’s disease is characterized by accumulation of α-synuclein (αSyn). Release of oligomeric/fibrillar αSyn from damaged neurons may potentiate neuronal death in part via microglial activation. Heretofore, it remained unknown if oligomeric/fibrillar αSyn could activate the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome in human microglia and whether anti-αSyn antibodies could prevent this effect. Here, we show that αSyn activates the NLRP3 inflammasome in human induced pluripotent stem cell (hiPSC)-derived microglia (hiMG) via dual stimulation involving Toll-like receptor 2 (TLR2) engagement and mitochondrial damage. In vitro, hiMG can be activated by mutant (A53T) αSyn secreted from hiPSC-derived A9-dopaminergic neurons. Surprisingly, αSyn–antibody complexes enhanced rather than suppressed inflammasome-mediated interleukin-1β (IL-1β) secretion, indicating these complexes are neuroinflammatory in a human context. A further increase in inflammation was observed with addition of oligomerized amyloid-β peptide (Aβ) and its cognate antibody. In vivo, engraftment of hiMG with αSyn in humanized mouse brain resulted in caspase-1 activation and neurotoxicity, which was exacerbated by αSyn antibody. These findings may have important implications for antibody therapies aimed at depleting misfolded/aggregated proteins from the human brain, as they may paradoxically trigger inflammation in human microglia.

MEF2C has been shown to be a critical transcription factor for neurodevelopment, whose loss-of-function mutation in humans results in MEF2C haploinsufficiency syndrome (MHS), a severe form of autism spectrum disorder (ASD)/intellectual disability (ID). Here, we use patient hiPSC-derived cerebrocortical neurons and cerebral organoids to characterize MHS deficits. Unexpectedly, we found an aberrant micro-RNA-mediated gliogenesis pathway that contributes to decreased neurogenesis. We also demonstrate network-level hyperexcitability in neurons, as evidenced by excessive synaptic and extrasynaptic activity contributing to excitatory/inhibitory (E/I) imbalance. Notably, the extrasynaptic NMDA receptor antagonist, NitroSynapsin, corrects this aberrant electrical activity associated with abnormal phenotypes. During neurodevelopment, MEF2C regulates many ASD-associated gene networks suggesting that our approach may lead to personalized therapy for multiple forms of ASD.One sentence summaryAutism-like MEF2C+/- patient hiPSC models show miRNA-mediated overproduction of astrocytes and hyperactivity of neurons.

We present a measurement of baryonic acoustic oscillations (BAO) from Lyman-$\alpha$ (Ly$\alpha$) absorption and quasars at an effective redshift $z=2.33$ using the complete extended Baryonic Oscillation Spectroscopic Survey (eBOSS). The sixteenth and final eBOSS data release (SDSS DR16) contains all data from eBOSS and its predecessor, the Baryonic Oscillation Spectroscopic Survey (BOSS), providing $210,005$ quasars with $z_{q}>2.10$ that are used to measure Ly$\alpha$ absorption. We measure the BAO scale both in the auto-correlation of Ly$\alpha$ absorption and in its cross correlation with $341,468$ quasars with redshift $z_{q}>1.77$. Apart from the statistical gain from new quasars and deeper observations, the main improvements over previous work come from more accurate modeling of physical and instrumental correlations and the use of new sets of mock data. Combining the BAO measurement from the auto- and cross-correlation yields the constraints of the two ratios $D_{H}(z=2.33)/r_{d} = 8.99 \pm 0.19$ and $D_{M}(z=2.33)/r_{d} = 37.5 \pm 1.1$, where the error bars are statistical. These results are within $1.5\sigma$ of the prediction of the flat-$\Lambda$CDM cosmology of Planck~(2016). The analysis code, \texttt{picca}, the catalog of the flux-transmission field measurements, and the $\Delta \chi^{2}$ surfaces are publicly available., Comment: 37 pages, 23 figures, Matches the published version by ApJ

Although reduced tidal volumes have improved patient survival during ventilation for acute lung injury, further improvements will require pharmacologic interventions of the cellular pathways for inflammation and injury. We previously reported that pretreatment with mitochondrial targeted mtDNA repair enzymes largely prevented lung injury and inflammation during a protocol for moderately severe ventilation induced lung injury. GSH/GSSG ratios indicated that free radical production had been reduced to baseline levels by treatment. The central role of the alveolar macrophages and cellular mechanisms of injury are discussed. This includes a rapid calcium entry and mitochondrial production of excessive reactive oxygen species. Excessive ROS can then result in activation of the NLRP3 inflammasome and secretion of IL-1 and IL-18 by caspase-1. A simultaneous activation of NFkB to transcribe pro forms of the cytokines is stimulated by damage associated molecular pattern (DAMP) recognition receptors. These are primarily TLR4 responding to various cellular damage products and TLR9 responding to mtDNA fragments that appear to be primarily involved. Intervention in these pathways could result in useful future clinical treatments.

Metabolic syndrome (MetS) and Type 2 diabetes mellitus (T2DM) increase risk for Alzheimer's disease (AD). The molecular mechanism for this association remains poorly defined. Here we report in human and rodent tissues that elevated glucose, as found in MetS/T2DM, and oligomeric β-amyloid (Aβ) peptide, thought to be a key mediator of AD, coordinately increase neuronal Ca2+ and nitric oxide (NO) in an NMDA receptor-dependent manner. The increase in NO results in S-nitrosylation of insulin-degrading enzyme (IDE) and dynamin-related protein 1 (Drp1), thus inhibiting insulin and Aβ catabolism as well as hyperactivating mitochondrial fission machinery. Consequent elevation in Aβ levels and compromise in mitochondrial bioenergetics result in dysfunctional synaptic plasticity and synapse loss in cortical and hippocampal neurons. The NMDA receptor antagonist memantine attenuates these effects. Our studies show that redox-mediated posttranslational modification of brain proteins link Aβ and hyperglycaemia to cognitive dysfunction in MetS/T2DM and AD., Alzheimer's disease is linked to metabolic syndrome and Type-2 diabetes, but the mechanism behind this association is unclear. Here, the authors show that elevated glucose and amyloid ß work together to increase nitrosative stress, leading to aberrant mitochondrial activity and synaptic dysfunction.

Transcription factor MEF2C regulates multiple genes linked to autism spectrum disorder (ASD), and human MEF2C haploinsufficiency results in ASD, intellectual disability, and epilepsy. However, molecular mechanisms underlying MEF2C haploinsufficiency syndrome remain poorly understood. Here we report that Mef2c +/−(Mef2c-het) mice exhibit behavioral deficits resembling those of human patients. Gene expression analyses on brains from these mice show changes in genes associated with neurogenesis, synapse formation, and neuronal cell death. Accordingly, Mef2c-het mice exhibit decreased neurogenesis, enhanced neuronal apoptosis, and an increased ratio of excitatory to inhibitory (E/I) neurotransmission. Importantly, neurobehavioral deficits, E/I imbalance, and histological damage are all ameliorated by treatment with NitroSynapsin, a new dual-action compound related to the FDA-approved drug memantine, representing an uncompetitive/fast off-rate antagonist of NMDA-type glutamate receptors. These results suggest that MEF2C haploinsufficiency leads to abnormal brain development, E/I imbalance, and neurobehavioral dysfunction, which may be mitigated by pharmacological intervention., Human MEF2C haploinsufficiency results in Autism Spectrum Disorder (ASD), but it is unclear if the same is true in mice. Here, the authors show that Mef2c +/−mice have behavioral defects and neuronal abnormalities similar to ASD, and symptoms can be ameliorated with the new drug, NitroSynapsin.

Small molecules enable OCT4-mediated direct reprogramming into expandable human neural stem cells

Significance S -nitrosylation, addition of an NO group to a cysteine thiol, can regulate protein activity. Aberrant protein S -nitrosylation, however, can disrupt normal enzyme function, as is the case for S -nitrosylated peroxiredoxin (SNO-Prx), which would otherwise catabolize toxic peroxides that occur under neurodegenerative conditions such as Parkinson’s disease. Here, we describe a paradigm of N -phosphorylation–mediated denitrosylation by the enzyme sulfiredoxin that removes NO from Prx. The findings are at the center of redox control of the cell, explaining reactivation by sulfiredoxin of both Prx-SO 2 H and SNO-Prx and thus describe a master regulator of redox reactions that combats nitrosative and oxidative stress in cells. These results suggest that sulfiredoxin may be an important target for therapeutic intervention in neurodegenerative disorders.

Ca2+ signals are commonly measured using fluorescent Ca2+ indicators and microscopy techniques, but manual analysis of Ca2+ measurements is time consuming and subject to bias. Automated region of interest (ROI) detection algorithms have been employed for identification of Ca2+ signals in one-dimensional line scan images, but currently there is no process to integrate acquisition and analysis of ROIs within two-dimensional time lapse image sequences. Therefore we devised a novel algorithm for rapid ROI identification and measurement based on the analysis of best-fit ellipses assigned to signals within noise-filtered image sequences. This algorithm was implemented as a plugin for ImageJ software (National Institutes of Health, Bethesda, MD). We evaluated the ability of our algorithm to detect synthetic Gaussian signal pulses embedded in background noise. The algorithm placed ROIs very near to the center of a range of signal pulses, resulting in mean signal amplitude measurements of 99.06 ± 4.11% of true amplitude values. As a practical application, we evaluated both agonist-induced Ca2+ responses in cultured endothelial cell monolayers, and subtle basal endothelial Ca2+ dynamics in opened artery preparations. Our algorithm enabled comprehensive measurement of individual and localized cellular responses within cultured cell monolayers. It also accurately identified characteristic Ca2+ transients, or Ca2+ pulsars, within the endothelium of intact mouse mesenteric arteries and revealed the distribution of this basal Ca2+ signal modality to be non-Gaussian with respect to amplitude, duration, and spatial spread. We propose that large-scale statistical evaluations made possible by our algorithm will lead to a more efficient and complete characterization of physiologic Ca2+-dependent signaling.

Acute lung injury is a general term that describes injurious conditions that can range from mild interstitial edema to massive inflammatory tissue destruction. This review will cover theoretical considerations and quantitative and semi-quantitative methods for assessing edema formation and increased vascular permeability during lung injury. Pulmonary edema can be quantitated directly using gravimetric methods, or indirectly by descriptive microscopy, quantitative morphometric microscopy, altered lung mechanics, high-resolution computed tomography, magnetic resonance imaging, positron emission tomography, or x-ray films. Lung vascular permeability to fluid can be evaluated by measuring the filtration coefficient (Kf) and permeability to solutes evaluated from their blood to lung clearances. Albumin clearances can then be used to calculate specific permeability-surface area products (PS) and reflection coefficients (σ). These methods as applied to a wide variety of transgenic mice subjected to acute lung injury by hyperoxic exposure, sepsis, ischemia-reperfusion, acid aspiration, oleic acid infusion, repeated lung lavage, and bleomycin are reviewed. These commonly used animal models simulate features of the acute respiratory distress syndrome, and the preparation of genetically modified mice and their use for defining specific pathways in these disease models are outlined. Although the initiating events differ widely, many of the subsequent inflammatory processes causing lung injury and increased vascular permeability are surprisingly similar for many etiologies.

A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described. The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow, tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead space liquid. FRC and arterial blood gases were maintained during ventilation with Rimar 101 PFC over 2-3 h in normal piglets and piglets with simulated pulmonary edema induced by instillation of albumin solution. Addition of tracheal insufflation flow significantly improved the blood gases and enhanced clearance of instilled albumin solution during simulated edema.

It has generally been assumed that movement of fluid between the pulmonary microvasculature and surrounding tissues is governed by a "Starling" balance of hydrostatic and protein osmotic forces similar to that which prevails in the extremities. However, both recent and older observations suggest that the lungs are more resistant to edema formation than most other organs. Several structural aspects of the lung may account for protection of the airspaces from edema formation. The pulmonary microvasculature, which comprises >70% of the pulmonary circulatory bed, appears to be less permeable to fluid and electrolytes than the endothelium of the pulmonary arteries and veins and other microvascular exchange areas. This arrangement may help explain why early edema is confined to the perivascular and peribronchial regions and why lymphatics do not reach the alveoli. Unlike the peripheral vasculature, which is compressed by edema formation, the extra-alveolar vessels remain tethered open by airway distention, even when interstitial pressures rise above those in the vessels. This may also facilitate return of proteins to the circulation. Ultrafiltration of plasma may lower local protein concentrations in the interstitium, thereby slowing further edema formation. Transendothelial reabsorption of fluid may also be altered by vesicular transport.

We have previously implicated calcium entry through stretch-activated cation channels in initiating the acute pulmonary vascular permeability increase in response to high peak inflation pressure (PIP) ventilation. However, the molecular identity of the channel is not known. We hypothesized that the transient receptor potential vanilloid-4 (TRPV4) channel may initiate this acute permeability increase because endothelial calcium entry through TRPV4 channels occurs in response to hypotonic mechanical stress, heat, and P-450 epoxygenase metabolites of arachidonic acid. Therefore, permeability was assessed by measuring the filtration coefficient (Kf) in isolated perfused lungs of C57BL/6 mice after 30-min ventilation periods of 9, 25, and 35 cmH2O PIP at both 35°C and 40°C. Ventilation with 35 cmH2O PIP increased Kf by 2.2-fold at 35°C and 3.3-fold at 40°C compared with baseline, but Kf increased significantly with time at 40°C with 9 cmH2O PIP. Pretreatment with inhibitors of TRPV4 (ruthenium red), arachidonic acid production (methanandamide), or P-450 epoxygenases (miconazole) prevented the increases in Kf. In TRPV4−/− knockout mice, the high PIP ventilation protocol did not increase Kf at either temperature. We have also found that lung distention caused Ca2+ entry in isolated mouse lungs, as measured by ratiometric fluorescence microscopy, which was absent in TRPV4−/− and ruthenium red-treated lungs. Alveolar and perivascular edema was significantly reduced in TRPV4−/− lungs. We conclude that rapid calcium entry through TRPV4 channels is a major determinant of the acute vascular permeability increase in lungs following high PIP ventilation.

Alveolar macrophages are the sentinel cell for activation of the inflammatory cascade when the lung is exposed to noxious stimuli. We investigated the role of macrophages in mechanical lung injury by comparing the effect of high-volume mechanical ventilation with or without prior depletion of macrophages. Randomized sham-controlled animal study in anesthetized rats. Lung injury was induced by 15 min of mechanical ventilation (intermittent positive pressure ventilation) using high peak pressures and zero end-expiratory pressure. The mean tidal volume was 40 ± 0.7 ml/kg. One group of animals was killed immediately after this period of volutrauma (HV), while in a second group normoventilation was continued for 2 h at a tidal volume less than 10 ml/kg (HV-LV). One-half of the animals were depleted of alveolar macrophages by pretreatment with intratracheal liposomal clodronate (CL2MDP). Arterial blood gas, blood pressure. After kill: lung static pressure volume curves, bronchoalveolar fluid concentration for protein, macrophage inflammatory protein 2, tumor necrosis factor α, and wet/dry lung weight ratio (W/D). During HV and HV+LV oxygenation, lung compliance, and alveolar stability were better preserved in animals pretreated with CL2MDP. In both groups W/D ratio was significantly greater in ventilated than in nonventilated animals (4.5 ± 0.6), but the increase in W/D was significantly less in CL2MDP treated HV and HV-LV groups (6.1 ± 0.4, 6.6 ± 0.6) than in the similarly ventilated nontreated groups (8.7 ± 0.2 and 9.2 ± 0.5). Alveolar macrophages participate in the early phase of ventilator-induced lung injury.

Transient receptor potential channel vanilloid 4 (TRPV4) is expressed in numerous cell types in lung, including vascular endothelium and smooth muscle, alveolar macrophages, airway epithelium, and airway smooth muscle. To date, our understanding of the role of TRPV4 in lung disease has been ­largely limited to its involvement in direct acute lung injury and lung injury induced by mechanical stress, specifically ventilator-induced lung injury and that due to high vascular pressure and edema formation in heart failure. We will discuss these areas in some depth. We will also introduce the evidence, albeit limited, for other lung diseases where TRPV4 may potentially play a role, including pulmonary hypertension, airway disease and cough, and thus therapeutics may prove beneficial. Although literature on the translation of bench research related to TRPV4 in lungs to clinical therapeutics is limited, we will discuss the available information.

Cyanide is a life-threatening, bioterrorist agent, preventing cellular respiration by inhibiting cytochrome c oxidase, resulting in cardiopulmonary failure, hypoxic brain injury, and death within minutes. However, even after treatment with various antidotes to protect cytochrome oxidase, cyanide intoxication in humans can induce a delayed-onset neurological syndrome that includes symptoms of Parkinsonism. Additional mechanisms are thought to underlie cyanide-induced neuronal damage, including generation of reactive oxygen species. This may account for the fact that antioxidants prevent some aspects of cyanide-induced neuronal damage. Here, as a potential preemptive countermeasure against a bioterrorist attack with cyanide, we tested the CNS protective effect of carnosic acid (CA), a pro-electrophilic compound found in the herb rosemary. CA crosses the blood-brain barrier to up-regulate endogenous antioxidant enzymes via activation of the Nrf2 transcriptional pathway. We demonstrate that CA exerts neuroprotective effects on cyanide-induced brain damage in cultured rodent and human-induced pluripotent stem cell-derived neurons in vitro, and in vivo in various brain areas of a non-Swiss albino mouse model of cyanide poisoning that simulates damage observed in the human brain. Cyanide, a potential bioterrorist agent, can produce a chronic delayed-onset neurological syndrome that includes symptoms of Parkinsonism. Here, cyanide poisoning treated with the proelectrophillic compound carnosic acid, results in reduced neuronal cell death in both in vitro and in vivo models through activation of the Nrf2/ARE transcriptional pathway. Carnosic acid is therefore a potential treatment for the toxic central nervous system (CNS) effects of cyanide poisoning. ARE, antioxidant responsive element; Nrf2 (NFE2L2, Nuclear factor (erythroid-derived 2)-like 2).

To determine the influence of experimental model and strain differences on the relationship of vascular permeability to inflammatory cytokine production after high peak inflation pressure (PIP) ventilation, we used isolated perfused mouse lung and intact mouse preparations of Balb/c and B6/129 mice ventilated at high and low PIP. Filtration coefficients in isolated lungs and bronchoalveolar lavage (BAL) albumin in intact mice increased within 20–30 min after initiation of high PIP in isolated Balb/c lungs and intact Balb/c, B6/129 wild-type, and p55 and p75 tumor necrosis factor (TNF) dual-receptor null mice. In contrast, the cytokine response was delayed and variable compared with the permeability response. In isolated Balb/c lungs ventilated with 25–27 cmH2O PIP, TNF-α, interleukin (IL)-1β, IL-1α, macrophage inflammatory protein (MIP)-2, and IL-6 concentrations in perfusate were markedly increased in perfusate at 2 and 4 h, but only MIP-2 was detectable in intact Balb/c mice using the same PIP. In intact wild-type and TNF dual-receptor null mice with ventilation at 45 cmH2O PIP, the MIP-2 and IL-6 levels in BAL were significantly increased after 2 h in both groups, but there were no differences between groups in the BAL albumin and cytokine concentrations or in lung wet-to-dry weight ratios. TNF-α was not be detected in BAL fluids in any group of intact mice. These results suggest that the alveolar hyperpermeability induced by high PIP ventilation occurs very rapidly and is initially independent of TNF-α participation and unlikely to depend on MIP-2 or IL-6.

The response of segmental filtration coefficients ( K f) to high peak inflation pressure (PIP) injury was determined in isolated perfused rat lungs. Total ( K f,t), arterial ( K f,a), and venous ( K f,v) filtration coefficients were measured under baseline conditions and after ventilation with 40–45 cmH2O PIP. K f,a and K f,v were measured under zone I conditions by increasing airway pressure to 25–27 cmH2O. The microvascular segment K f ( K f,mv) was then calculated by: K f,mv = K f,t − K f,a − K f,v. The baseline K f,twas 0.090 ± 0.022 ml · min−1 · cmH2O−1 · 100 g−1 and segmentally distributed 18% arterial, 41% venous, and 41% microvascular. After high PIP injury, K f,t increased by 680%, whereas K f,a, K f,v, and K f,mv increased by 398, 589, and 975%, respectively. Pretreatment with 50 μM gadolinium chloride prevented the high PIP-induced increase in K f in all vascular segments. These data imply a lower hydraulic conductance for microvascular endothelium due to its large surface area and a gadolinium-sensitive high-PIP injury, produced in both alveolar and extra-alveolar vessel segments.

Alzheimer’s disease (AD) is characterized by synaptic and neuronal loss, which occurs at least partially through oxidative stress induced by oligomeric amyloid-β (Aβ)-peptide. Carnosic acid (CA), a chemical found in rosemary and sage, is a pro-electrophilic compound that is converted to its active form by oxidative stress. The active form stimulates the Keap1/Nrf2 transcriptional pathway and thus production of phase 2 antioxidant enzymes. We used both in vitro and in vivo models. For in vitro studies, we evaluated protective effects of CA on primary neurons exposed to oligomeric Aβ. For in vivo studies, we used two transgenic mouse models of AD, human amyloid precursor protein (hAPP)-J20 mice and triple transgenic (3xTg AD) mice. We treated these mice trans-nasally with CA twice weekly for 3 months. Subsequently, we performed neurobehavioral tests and quantitative immunohistochemistry to assess effects on AD-related phenotypes, including learning and memory, and synaptic damage. In vitro, CA reduced dendritic spine loss in rat neurons exposed to oligomeric Aβ. In vivo, CA treatment of hAPP-J20 mice improved learning and memory in the Morris water maze test. Histologically, CA increased dendritic and synaptic markers, and decreased astrogliosis, Aβ plaque number, and phospho-tau staining in the hippocampus. We conclude that CA exhibits therapeutic benefits in rodent AD models and since the FDA has placed CA on the ‘generally regarded as safe’ (GRAS) list, thus obviating the need for safety studies, human clinical trials will be greatly expedited.

Current emphasis on translational application of genetic models of lung disease has renewed interest in the measurement of the gravimetric filtration coefficient ( Kf) as a means to assess vascular permeability changes in isolated perfused lungs. The Kfis the product of the hydraulic conductivity and the filtration surface area, and is a sensitive measure of vascular fluid permeability when the pulmonary vessels are fully recruited and perfused. We have observed a remarkable consistency of the normalized baseline Kfvalues between species with widely varying body weights from mice to sheep. Uniformity of Kfvalues can be attributed to the thin alveolar capillary barrier required for gas exchange and the conserved matching of lung vascular surface area to the oxygen requirements of the body mass. An allometric correlation between the total lung filtration coefficient ( Kf,t) and body weight in several species ( r2= 1.00) had a slope that was similar to those reported for alveolar and pulmonary capillary surface areas and pulmonary diffusion coefficients determined by morphometric methods in these species. A consistent Kfis dependent on accurately separating the filtration and vascular volume components of lung weight gain, then Kfis a consistent and repeatable index of lung vascular permeability.

Recent permeability studies comparing endothelial cell phenotypes derived from alveolar and extra-alveolar vessels have significant implications for interpreting the mechanisms of fluid homeostasis in the intact lung. These studies indicate that confluent monolayers of rat pulmonary microvascular endothelial cells had a hydraulic conductance ( Lp) that was only 5% and a transendothelial flux rate for 72-kDa dextran only 9% of values determined for rat pulmonary artery endothelial cell monolayers. On the basis of previous studies partitioning the filtration coefficients between alveolar and extra-alveolar vascular segments in rat lungs and previous studies of lymph albumin fluxes and permeability, the contribution of the alveolar capillary segment to total albumin flux in lymph was estimated to be less than 10%. In addition, the Starling safety factors against the edema calculated for the alveolar capillaries are quite different from those estimated for whole lung. Estimates of the edema safety factor due to increased filtration across the alveolar capillary wall based on the low Lp indicate it is quantitatively the greatest safety factor, although it would be a minor safety factor for extra-alveolar vessels. Also, a markedly higher effective protein osmotic absorptive force for plasma proteins must occur in the capillaries relative to extra-alveolar vessels. The lower Lp for alveolar capillaries also has implications for the sequence of hydrostatic edema formation, and it also may have a role in preventing exercise-induced alveolar flooding.

We determined whether drugs which modulate the state of protein tyrosine phosphorylation could alter the threshold for high airway pressure-induced microvascular injury in isolated perfused rat lungs. Lungs were ventilated for successive 30-min periods with peak inflation pressures (PIP) of 7, 20, 30, and 35 cmH2O followed by measurement of the capillary filtration coefficient ( Kfc), a sensitive index of hydraulic conductance. In untreated control lungs, Kfcincreased by 1.3- and 3.3-fold relative to baseline (7 cmH2O PIP) after ventilation with 30 and 35 cmH2O PIP. However, in lungs treated with 100 μM phenylarsine oxide (a phosphotyrosine phosphatase inhibitor), Kfcincreased by 4.7- and 16.4-fold relative to baseline at these PIP values. In lungs treated with 50 μM genistein (a tyrosine kinase inhibitor), Kfcincreased significantly only at 35 cmH2O PIP, and the three groups were significantly different from each other. Thus phosphotyrosine phosphatase inhibition increased the susceptibility of rat lungs to high-PIP injury, and tyrosine kinase inhibition attenuated the injury relative to the high-PIP control lungs.

To determine the initial signaling event in the vascular permeability increase after high airway pressure injury, we compared groups of lungs ventilated at different peak inflation pressures (PIPs) with (gadolinium group) and without (control group) infusion of 20 μM gadolinium chloride, an inhibitor of endothelial stretch-activated cation channels. Microvascular permeability was assessed by using the capillary filtration coefficient ( K fc), a measure of capillary hydraulic conductivity. K fc was measured after ventilation for 30-min periods with 7, 20, and 30 cmH2O PIP with 3 cmH2O positive end-expiratory pressure and with 35 cmH2O PIP with 8 cmH2O positive end-expiratory pressure. In control lungs, K fc increased significantly to 1.8 and 3.7 times baseline after 30 and 35 cmH2O PIP, respectively. In the gadolinium group, K fc was unchanged from baseline (0.060 ± 0.010 ml ⋅ min−1 ⋅ cmH2O−1 ⋅ 100 g−1) after any PIP ventilation period. Pulmonary vascular resistance increased significantly from baseline in both groups before the last K fc measurement but was not different between groups. These results suggest that microvascular permeability is actively modulated by a cellular response to mechanical injury and that stretch-activated cation channels may initiate this response through increases in intracellular calcium concentration.

Parker, James C., Ellen C. Breen, and John B. West.High vascular and airway pressures increase interstitial protein mRNA expression in isolated rat lungs. J. Appl. Physiol. 83(5): 1697–1705, 1997.—We hypothesized that wall stresses produced by high peak airway (Paw) and venous (Ppv) pressures would increase mRNA levels for structural proteins of the interstitial matrix in isolated rat lungs. Groups of lungs ( n = 6) were perfused for 4 h at a peak Paw of 35 cmH2O (HiPaw), cyclical peak Ppv of 28 cmH2O (HiPv), or baseline vascular and airway pressures (LoPress). In two separate groups, comparable peak pressures increased capillary filtration coefficient fourfold in each group. Northern blots were probed for mRNA of α1(I), α1(III), and α2(IV) procollagen chains, laminin B chain, fibronectin, and transforming growth factor-β1, and densities were normalized to 18S rRNA. mRNA was significantly higher in the HiPv group for type I (4.3-fold) and type III (3.8-fold) procollagen and laminin B chain (4.8-fold) and in the HiPaw group for type I (2.4-fold) and type IV (4.5-fold) procollagen and laminin B chain (2.3-fold) than in the LoPress group. Only fibronectin mRNA was significantly increased (3.9-fold) in the LoPress group relative to unperfused lungs. Estimated wall stresses were highest for alveolar septa in the HiPaw group and for capillaries in the HiPv group. The different patterns of mRNA expression are attributed to different regional stresses or extent of injury.

Parker, James C., Chris B. Cave, Jeffrey L. Ardell, Charles R. Hamm, and Susan G. Williams. Vascular tree structure affects lung blood flow heterogeneity simulated in three dimensions. J. Appl. Physiol. 83(4): 1370–1382, 1997.—Pulmonary arterial tree structures related to blood flow heterogeneity were simulated by using a symmetrical, bifurcating model in three-dimensional space. The branch angle (Θ), daughter-parent length ratio ( rL ), branch rotation angle (φ), and branch fraction of parent flow (γ) for a single bifurcation were defined and repeated sequentially through 11 generations. With φ fixed at 90°, tree structures were generated with Θ between 60 and 90°, rL between 0.65 and 0.85, and an initial segment length of 5.6 cm and sectioned into 1-cm3 samples for analysis. Blood flow relative dispersions (RD%) between 52 and 42% and fractal dimensions ( D s) between 1.20 and 1.15 in 1-cm3samples were observed even with equal branch flows. When γ ≠ 0.5, RD% increased, but D s either decreased with gravity bias of higher branch flows or increased with random assignment of higher flows. Blood flow gradients along gravity and centripetal vectors increased with biased flow assignment of higher flows, and blood flows correlated negatively with distance only when γ ≠ 0.5. Thus a recursive branching vascular tree structure simulated D s and RD% values for blood flow heterogeneity similar to those observed experimentally in the pulmonary circulation due to differences in the number of terminal arterioles per 1-cm3 sample, but blood flow gradients and a negative correlation of flows with distance required unequal partitioning of blood flows at branch points.

In previous studies, blockade or gene deletion of either myosin light chain kinase (MLCK) or the mechanogated transient receptor potential vanilloid 4 (TRPV4) channel attenuated mechanical lung injury. To determine their effects on calcium entry, rat pulmonary microvascular endothelial cells (RPMVEC) were labeled with fluo-4 and calcium entry initiated with the TRPV4 agonist, 4α-phorbol 12, 13-didecanoate (4αPDD). Mean calcium transients peaked at ∼25 sec and persisted ∼500 sec. The 4αPDD response was essentially abolished in calcium-free media, or after pretreatment with the MLCK inhibitor, ML-7. ML-7 also attenuated the 4αPDD-induced inward calcium current measured directly using whole-cell patch clamp. Pretreatment with dynasore, an inhibitor of dynamin produced an initial calcium transient followed by a 4αPDD transient of unchanged peak intensity. Automated averaging of areas under the curve (AUC) of calcium transients in individual cells indicated total calcium activity with a relationship between treatment groups of ML-7 + 4αPDD < 4αPDD only < dynasore + 4αPDD. Measurement of biotinylated surface TRPV4 protein indicated a significant reduction after ML-7 pretreatment, but no significant change with dynasore treatment. RPMVEC monolayer electrical resistances were decreased by only 3% with 10 μmol/L 4αPDD and the response was dose-related. Dynasore alone produced a 29% decrease in resistance, but neither ML-7 nor dynasore affected the subsequent 4αPDD resistance response. These studies suggest that MLCK may inhibit mechanogated calcium responses through reduced surface expression of stretch activated TRPV4 channels in the plasma membrane.

Synaptic loss is the cardinal feature linking neuropathology to cognitive decline in Alzheimer’s disease (AD). However, the mechanism of synaptic damage remains incompletely understood. Here, using FRET-based glutamate sensor imaging, we show that amyloid-β peptide (Aβ) engages α7 nicotinic acetylcholine receptors to induce release of astrocytic glutamate, which in turn activates extrasynaptic NMDA receptors (eNMDARs) on neurons. In hippocampal autapses, this eNMDAR activity is followed by reduction in evoked and miniature excitatory postsynaptic currents (mEPSCs). Decreased mEPSC frequency may reflect early synaptic injury because of concurrent eNMDAR-mediated NO production, tau phosphorylation, and caspase-3 activation, each of which is implicated in spine loss. In hippocampal slices, oligomeric Aβ induces eNMDAR-mediated synaptic depression. In AD-transgenic mice compared with wild type, whole-cell recordings revealed excessive tonic eNMDAR activity accompanied by eNMDAR-sensitive loss of mEPSCs. Importantly, the improved NMDAR antagonist NitroMemantine, which selectively inhibits extrasynaptic over physiological synaptic NMDAR activity, protects synapses from Aβ-induced damage both in vitro and in vivo.

We evaluated the effects of pulmonary infiltration of eosinophils without exogenous activators on airway and vascular hyperresponsiveness to muscarinic challenge in the lungs of rats infected with Toxocara [correction of Toxicara] canis, the canine round worm. Bronchoalveolar lavage of infected lungs produced 4.26 x 10(7) cells with 85% eosinophils, 15% mononuclear cells, and essentially no neutrophils. Eosinophils were present in the air spaces and interstitial spaces surrounding airways and vessels. The smooth muscle thickness increased about fourfold in large airways and vessels, and medium and small vessels were muscularized in infected lungs. In the T. canis-infected lungs, baseline airway resistance increased 288%, total vascular resistance (RT) increased 202%, and capillary filtration coefficient increased 208% compared with uninfected control lungs. Lung compliance was 56% of control. The concentration of acetylcholine that produced 50% of maximal response was 18.4 times greater for airway resistance and 18.7 times greater for RT in uninfected controls than in infected lungs. Isoproterenol (10(-4) M) decreased RT and peak airway pressure by 21% in infected lungs but had no significant effect on controls. We conclude that pulmonary interstitial infiltrates of eosinophils cause airway and vascular remodeling and increase baseline resistances and muscarinic reactivities of airways and vessels in rat lungs infected with T. canis.

Objective To determine whether intubation and ventilation with either conventional mechanical ventilation or high-frequency jet ventilation, using dry or humidified gas, could induce regional tracheal ischemia and serve as a basis for the tracheal necrosis observed clinically during ventilation. Design Prospective, multiple group, controlled experimental study. Setting Medical school research laboratory. Subjects Twenty, 3- to 5-wk-old suckling pigs. Interventions Anesthetized, closed-chest piglets were intubated and ventilated for 30 mins with conventional mechanical ventilation and then ventilated for 2 additional hrs with either conventional mechanical ventilation or high-frequency jet ventilation. Groups were also ventilated, using both modes of ventilation, with either 37 degrees C humidified gas or 25 degrees C dry gas. Measurements and main results Blood flow groups were compared during spontaneous breathing, conventional mechanical ventilation, high-frequency jet ventilation and both ventilation modes, using 37 degrees C humidified or 22 degrees C dry inspired gas. Groups were compared, using an analysis of variance with a Newman-Keul's post-test. Regional tracheal blood flow was measured, using radioactive microspheres. Cardiac output and organ blood flows were also monitored. Tracheal blood flow increased 10.3-fold within 30 mins after intubation, but there were no significant differences in regional or total tracheal blood flow between conventional mechanical ventilation and high-frequency jet ventilation, using 37 degrees C humidified gas. Tracheal blood flow was increased further using high-frequency jet ventilation and 25 degrees C dry gas but not conventional mechanical ventilation with dry gas. Although ventilation reduced cardiac output by approximately 30%, there were no significant differences in organ distribution between modes of ventilation. Conclusions Acute tracheal hyperemia occurred with intubation and ventilation with both conventional mechanical ventilation and high-frequency jet ventilation but no differences were observed between ventilation modes. Hyperemia was further increased with cool, dry inspired gas, using high-frequency jet ventilation but not conventional mechanical ventilation. Although acute tracheal ischemia was not produced by high-frequency jet ventilation or conventional mechanical ventilation, factors which alter the balance between arterial supply and metabolic demand or induce inflammation may contribute to the tracheal necrosis reported during sustained ventilation.

This study tested the hypothesis that oxidative mitochondrial-targeted DNA (mtDNA) damage triggered ventilator-induced lung injury (VILI). Control mice and mice infused with a fusion protein targeting the DNA repair enzyme, 8-oxoguanine-DNA glycosylase 1 (OGG1) to mitochondria were mechanically ventilated with a range of peak inflation pressures (PIP) for specified durations. In minimal VILI (1 h at 40 cmH2O PIP), lung total extravascular albumin space increased 2.8-fold even though neither lung wet/dry (W/D) weight ratios nor bronchoalveolar lavage (BAL) macrophage inflammatory protein (MIP)-2 or IL-6 failed to differ from nonventilated or low PIP controls. This increase in albumin space was attenuated by OGG1. Moderately severe VILI (2 h at 40 cmH2O PIP) produced a 25-fold increase in total extravascular albumin space, a 60% increase in W/D weight ratio and marked increases in BAL MIP-2 and IL-6, accompanied by oxidative mitochondrial DNA damage, as well as decreases in the total tissue glutathione (GSH) and GSH/GSSH ratio compared with nonventilated lungs. All of these injury indices were attenuated in OGG1-treated mice. At the highest level of VILI (2 h at 50 cmH2O PIP), OGG1 failed to protect against massive lung edema and BAL cytokines or against depletion of the tissue GSH pool. Interestingly, whereas untreated mice died before completing the 2-h protocol, OGG1-treated mice lived for the duration of observation. Thus mitochondrially targeted OGG1 prevented VILI over a range of ventilation times and pressures and enhanced survival in the most severely injured group. These findings support the concept that oxidative mtDNA damage caused by high PIP triggers induction of acute lung inflammation and injury.

Although lymphatic washout of hyaluronan during lung hydration has been postulated to deplete lung interstitial hyaluronan content and thereby contribute to the decreased interstitial exclusion of albumin observed under these conditions, this hypothesis has not been directly tested. In anesthetized, ventilated mongrel dogs, a prenodal lung lymphatic was cannulated for measurement of lymph flow and hyaluronan concentration. Following baseline measurements, Pla was increased in four steps of 5 cm H2O in Group 1 or set to one pressure ranging between 6 and 32 cm H2O in Group 2. In Group 3, saline (15% body weight) was infused over 30 min and then Pla increased as in Group 2. Invariably, as lymph flow increased in Groups 1 through 3, lymph hyaluronan concentration and hyaluronan flux increased significantly (p0.05). In a separate control group, there were no changes in lymph flow, hyaluronan concentration, or hyaluronan flux. In Group 3, lung hyaluronan content at 5 h (0.76 +/- 0.08 mg/g dry weight) was not significantly less than that during baseline (0.88 +/- 0.05 mg/g dry weight), although total uronic acid content actually increased by 38% over the same time course. In contrast, in the control group, both lung hyaluronan and uronic acid content remained stable over the experimental period. From these data, approximately 2 to 3% of lung hyaluronan is predicted to leave the interstitium via lymphatic flux per day under baseline conditions. The daily turnover of interstitial hyaluronan by this route increased to 15 to 18% of total content when Pla was elevated and to 54% following saline infusion. Thus, lung hyaluronan can be rapidly mobilized with increased lymph flow.(ABSTRACT TRUNCATED AT 250 WORDS)

We describe an electrical seismic gun that is capable of firing 8-gauge blank black powder shells in a water‐filled borehole under relatively high hydrostatic pressures. The new seismic gun is a modified version of the electrical shotgun source for engineering seismic surveys introduced by Pullan and MacAulay (1987). Our modifications seal the firing circuit and 8-gauge shell against water entry so underwater detonation will occur reliably at depths to at least 80 m (0.9 MPa atmospheric pressure). Source energy is controlled by varying the size of the black powder load in the shell from 50 grains to 500 grains (10 kJ to 100 kJ). Although our seismic gun may be used in any seismic application suitable for modest explosive charges, it was initially developed as a versatile source for use in seismic investigations of the shallow subsurface (primarily engineering and groundwater studies). As of this writing, the gun has been used for optimum offset and CMP high‐resolution seismic reflection profiling, engineering refraction surveys, fixed‐source and variable‐source noise tests, and vertical traveltime measurements in water wells. Other potential uses include VSP and borehole‐to‐surface or borehole‐to‐borehole seismic tomography.

Eosinophils have been implicated as effector cells in producing vascular and bronchial constriction and increased microvascular permeability in the lung. Hypohalous acids produced by the eosinophil peroxidase (EPO)-hydrogen peroxide (H2O2)-halide system are stable cytotoxic oxidants. We measured the effects of EPO inhibition in activated eosinophils on vascular permeability, assessed using the capillary filtration coefficient (Kf,c), vascular resistance (Rt,vasc), and airway resistance (Raw) in isolated rat lungs perfused with 5% bovine albumin in Kreb's solution. Eosinophils were harvested by bronchoalveolar lavage of Toxicara canis-infected rats. Infusion of 2 x 10(6) phorbol myristate acetate (PMA)-activated cells produced a 3.3-fold increase in Rt,vasc at 30 min, primarily caused by small vessel constriction, a 2.5-fold increase in Raw at 150 min, and a 1.8-fold increase in Kf,c at 90 min. Inhibition of EPO using 3-amino-1,2,4-triazole (3-AT) prevented the increases in Kf,c, but not those in eosinophil superoxide production, Rt,vasc, or Raw. Addition of 2 mM sodium bromide as preferential EPO substrate caused Kf,c, but not Rt,vasc, or Raw, to increase significantly (2.5-fold) compared with activated eosinophils alone. Thus, the acute changes in microvascular permeability were modulated by activity of the EPO-H2O2-Halide system, but the increased vascular and bronchial resistances were mediated through a different pathway.

To describe the physiologic mechanisms of ventilator-induced lung injury and to define the major ventilator and host-dependent risk factors that contribute to such injury.Basic science and clinical studies related to ventilator-induced barotrauma and lung pathophysiology.Emphasis on controlled, experimental studies and clinical studies related to specific mechanisms.Preference given to studies with quantitative end-points to assess damage and causal relationships.Related studies are integrated to obtain basic mechanisms of damage where possible.Ventilation with high tidal volumes can increase vascular filtration pressures; produce stress fractures of capillary endothelium, epithelium, and basement membrane; and cause lung rupture. Mechanical damage leads to leakage of fluid, protein, and blood into tissue and air spaces or leakage of air into tissue spaces. This process is followed by an inflammatory response and possibly a reduced defense against infection. Predisposing factors for lung injury are high peak inspiratory volumes and pressures, a high mean airway pressure, structural immaturity of lung and chest wall, surfactant insufficiency or inactivation, and preexisting lung disease. Damage can be minimized by preventing overdistention of functional lung units during therapeutic ventilation.

We have previously implicated transient receptor potential vanilloid 4 (TRPV4) channels and alveolar macrophages in initiating the permeability increase in response to high peak inflation pressure (PIP) ventilation. Alveolar macrophages were harvested from TRPV4−/−and TRPV4+/+mice and instilled in the lungs of mice of the opposite genotype. Filtration coefficients ( Kf) measured in isolated perfused lungs after ventilation with successive 30-min periods of 9, 25, and 35 cmH2O PIP did not significantly increase in lungs from TRPV4−/−mice but increased >2.2-fold in TRPV4+/+lungs, TRPV4+/+lungs instilled with TRPV4−/−macrophages, and TRPV4−/−lungs instilled with TRPV4+/+macrophages after ventilation with 35 cmH2O PIP. Activation of TRPV4 with 4-α-phorbol didecanoate (4αPDD) significantly increased intracellular calcium, superoxide, and nitric oxide production in TRPV4+/+macrophages but not TRPV4−/−macrophages. Cross-sectional areas increased nearly 3-fold in TRPV4+/+macrophages compared with TRPV4−/−macrophages after 4αPDD. Immunohistochemistry staining of lung tissue for nitrotyrosine revealed increased amounts in high PIP ventilated TRPV4+/+lungs compared with low PIP ventilated TRPV4+/+or high PIP ventilated TRPV4−/−lungs. Thus TRPV4+/+macrophages restored susceptibility of TRPV4−/−lungs to mechanical injury. A TRPV4 agonist increased intracellular calcium and reactive oxygen and nitrogen species in harvested TRPV4+/+macrophages but not TRPV4−/−macrophages. Kfincreases correlated with tissue nitrotyrosine, a marker of peroxynitrite production.

The transient receptor potential vanilloid 4 (TRPV4) non-selective cation channel has emerged as a critical channel for initiating the increased vascular permeability induced by high airway or vascular pressures in the lung. TRPV4 gating is regulated by multiple factors: mechanical stress, heat, epoxyeicosatrienoic acids (EETs) – the arachidonic acid metabolites of P450 epoxygenases, and phorbol esters. Increased pulmonary venous pressure and ventilation with high peak inflation pressures increase endothelial calcium influx, nitric oxide production, and vascular permeability in a TRPV4 dependent fashion in intact lungs. The permeability response to excess mechanical stress is attenuated by inhibition of cytosolic phospholipase A2 or P450 epoxygenases, and permeability increases in response to infusion of EETs. Various molecular mechanisms have been implicated for regulating TRPV4 gating, including channel translocation, direct ligand binding and phosphorylation. However, the mechanisms for EET dependent regulation of TRPV4 or amplification of TRPV4 by phosphorylation in intact lungs subjected to mechanical stress have not been clarified.

The protective effect of oxygen radical scavengers on lung injury induced by activated eosinophils was examined in isolated perfused rat lungs. Eosinophils were obtained by bronchoalveolar lavage from rats infected with Toxocara canis and activated with phorbol myristate acetate (PMA). There were no changes in pulmonary vascular (RT) and airway (Raw) resistances and only minimal changes in vascular permeability assessed using the capillary filtration coefficient (Kf,c) in PMA control lungs and nonactivated eosinophil-treated lungs. In lungs receiving 3 x 10(6) PMA-activated eosinophils, there were significant increases from baseline of 7.3-fold in RT at 30 min, primarily due to the constriction of small arteries and veins; 3.6-fold in Kf,c at 90 and 130 min; and 2.5-fold in Raw. The lungs also became markedly edematous. Both superoxide dismutase and catalase pretreatment prevented the significant increase in Kf,c and lung wet-to-dry weight ratios and partially attenuated the increase in Raw, but did not significantly inhibit the increase in RT induced by activated eosinophils. Heat-inactivated catalase did not attenuate the eosinophil-induced increases in Kf,c, Raw, or RT. Thus, activated eosinophils acutely increased microvascular permeability primarily through production of oxygen free radicals. The free radical scavengers superoxide dismutase and catalase partially attenuated the bronchoconstriction but had no significant effect on the vasoconstriction induced by activated eosinophils.

Parkinson’s disease (PD) is characterized by loss of A9 dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). An association has been reported between PD and exposure to mitochondrial toxins, including environmental pesticides paraquat, maneb, and rotenone. Here, using a robust, patient-derived stem cell model of PD allowing comparison of A53T α-synuclein (α-syn) mutant cells and isogenic mutation-corrected controls, we identify mitochondrial toxin-induced perturbations in A53T α-syn A9 DA neurons (hNs). We report a pathway whereby basal and toxin-induced nitrosative/oxidative stress results in S-nitrosylation of transcription factor MEF2C in A53T hNs compared to corrected controls. This redox reaction inhibits the MEF2C-PGC1α transcriptional network, contributing to mitochondrial dysfunction and apoptotic cell death. Our data provide mechanistic insight into gene-environmental interaction (GxE) in the pathogenesis of PD. Furthermore, using small-molecule high-throughput screening, we identify the MEF2C-PGC1α pathway as a therapeutic target to combat PD., Parkinson Society Canada (Fellowship), United Mitochondrial Disease Foundation (grant), National Institutes of Health (U.S.) (NIH grant P01 HD29587), National Institutes of Health (U.S.) (NIH grant P01 ES016738), National Institutes of Health (U.S.) (NIH grant P30 NS076411), National Institutes of Health (U.S.) (NIH grant R37 CA084198)

International audience; AIMS: We investigated whether rapid cooling instituted by total liquid ventilation (TLV) improves cardiac and mitochondrial function in rabbits submitted to ischaemia-reperfusion. METHODS AND RESULTS: Rabbits were chronically instrumented with a coronary artery occluder and myocardial ultrasonic crystals for assessment of segment length-shortening. Two weeks later they were re-anaesthetized and underwent either a normothermic 30-min coronary artery occlusion (CAO) (Control group, n = 7) or a comparable CAO with cooling initiated by a 10-min hypothermic TLV and maintained by a cold blanket placed on the skin. Cooling was initiated after 5 or 15 min of CAO (Hypo-TLV and Hypo-TLV(15') groups, n = 6 and 5, respectively). A last group underwent normothermic TLV during CAO (Normo-TLV group, n = 6). Wall motion was measured in the conscious state over three days of reperfusion before infarct size evaluation and histology. Additional experiments were done for myocardial sampling in anaesthetized rabbits for mitochondrial studies. The Hypo-TLV procedure induced a rapid decrease in myocardial temperature to 32-34 degrees C. Throughout reperfusion, segment length-shortening was significantly increased in Hypo-TLV and Hypo-TLV(15') vs. Control and Normo-TLV (15.1 +/- 3.3%, 16.4 +/- 2.3%, 1.8 +/- 0.6%, and 1.1 +/- 0.8% at 72 h, respectively). Infarct sizes were also considerably attenuated in Hypo-TLV and Hypo-TLV(15') vs. Control and Normo-TLV (4 +/- 1%, 11 +/- 5%, 39 +/- 2%, and 42 +/- 5% infarction of risk zones, respectively). Mitochondrial function in myocardial samples obtained at the end of ischaemia or after 10 min of reperfusion was improved by Hypo-TLV with respect to ADP-stimulated respiration and calcium-induced opening of mitochondrial permeability transition pores (mPTP). Calcium concentration opening mPTP was, e.g., increased at the end of ischaemia in the risk zone in Hypo-TLV vs. Control (157 +/- 12 vs. 86 +/- 12 microM). Histology and electron microscopy also revealed better preservation of lungs and of cardiomyocyte ultrastructure in Hypo-TLV when compared with Control. CONCLUSION: Institution of rapid cooling by TLV during ischaemia reduces infarct size as well as other sequelae of ischaemia, such as post-ischaemic contractile and mitochondrial dysfunction.

To evaluate albumin transport across the pulmonary capillary endothelial and interstitial barriers, we simultaneously measured blood-to-tissue (QA,t) and blood-to-lymph (QA,l) clearances of 125I-radiolabeled albumin as well as endogenous albumin clearance (Qa,l) in the canine lung in vivo (n = 10). Steady-state prenodal lung lymph flows (Qw,l) and protein clearances were measured over a 2-h period at a constant capillary pressure (Pc, 13-33 cmH2O). Comparison between QA,t and QA,l as a function of Pc suggests that little of the albumin that crossed the capillary wall remained in the lung tissue, with most leaving in the lymph. Qw,l increased significantly as Pc increased, but lung tissue water was minimally affected. From the ratio of the clearance-Pc slopes for albumin and water, the albumin reflection coefficient was estimated to be 0.81 using QA,l and Qw,l and 0.56 using Qa,l and Qw,l. The permeability surface area product for the sum of blood-to-tissue and blood-to-lymph fluxes of labeled albumin (QA,t + QA,l) was 31 +/- 9 microliters/min, whereas that calculated from the blood-to-lymph flux of endogenous albumin (Qa,l) was 97 +/- 22 microliters/min. These data suggest that 1) both tissue and lymph accumulations of albumin must be considered when microvascular permeability is evaluated using protein tracers; 2) lymph clearance, but not tissue accumulation of albumin, was filtration dependent; and 3) lymph flow was an important contributor to the safety factor against edema formation over a moderate range of capillary pressures.

Objective We studied the effect of age on the development of pulmonary barotrauma after mechanical ventilation with high peak inspiratory pressures (PIP). Design Young (4 to 6 wk old) and adult rabbits were ventilated for 1 hr at PIPs of 15, 30, and either 45 cm H2O (young group) or 55 cm H2O (adult group). Measurements and main results The pulmonary capillary filtration coefficient (Kf,c) was measured in an isolated lung perfusion system after the animals were killed. In young rabbits, Kf,c increased significantly from the 15 cm H2O PIP value in both the 30 cm H2O (55%) and 45 cm H2O (507%) PIP groups, whereas Kf,c was increased in adult rabbits only in the 55 cm H2O (113%) PIP group. Kf,c was significantly (p less than .01) higher in young rabbits than in adult rabbits after ventilation, with every level of PIP being 91% higher at 15 cm H2O PIP and 440% higher at 45 to 55 cm H2O PIP. Also, a greater incidence of pneumothorax and airleaks was observed in the young rabbits. Pressure-volume loops demonstrated that the young rabbits had more compliant lungs and chest wall than adult rabbits. Conclusions These data indicate that the lungs of young rabbits had a higher baseline microvascular permeability and were more susceptible to the development of ventilator-induced increased microvascular permeability. More compliant lungs and chest wall and the larger distending volumes attained at each peak airway pressure appear to be the mechanisms.