Background and Purpose
Chronic obstructive pulmonary disease, encompassing chronic airway obstruction and lung emphysema, is a major worldwide health problem and a severe socio‐economic burden. ...Evidence previously provided by our group has shown that inhibition of inducible NOS (iNOS) prevents development of mild emphysema in a mouse model of chronic tobacco smoke exposure and can even trigger lung regeneration. Moreover, we could demonstrate that pulmonary hypertension is not only abolished in cigarette smoke‐exposed iNOS−/− mice but also precedes emphysema development. Possible regenerative effects of pharmacological iNOS inhibition in more severe models of emphysema not dependent on tobacco smoke, however, are hitherto unknown.
Experimental Approach
We have established a mouse model using a single dose of porcine pancreatic elastase or saline, intratracheally instilled in C57BL/6J mice. Emphysema, as well as pulmonary hypertension development was determined by both structural and functional measurements.
Key Results
Our data revealed that (i) emphysema is fully established after 21 days, with the same degree of emphysema after 21 and 28 days post instillation, (ii) emphysema is stable for at least 12 weeks and (iii) pulmonary hypertension is evident, in contrast to smoke models, only after emphysema development. Oral treatment with the iNOS inhibitor N(6)‐(1‐iminoethyl)‐l‐lysine (L‐NIL) was started after emphysema establishment and continued for 12 weeks. This resulted in significant lung regeneration, evident in the improvement of emphysema and reversal of pulmonary hypertension.
Conclusion and Implications
Our data indicate that iNOS is a potential new therapeutic target to treat severe emphysema and associated pulmonary hypertension.
LINKED ARTICLES
This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.1/issuetoc
We report the development of a table-top high peak power Titanium:Sapphire (Ti:Sa) CPA laser working at 100 Hz capable of delivering 205 mJ, 55 fs pulses. Every amplification stage is pumped by ...Nd-doped solid-state lasers and fully powered by diodes. Thermal effects in the Ti:Sa amplifiers are compensated passively with optics. This system is intended to be used for proton acceleration experiments at high repetition rates.
Chronic obstructive lung disease (COPD) is a common cause of death in industrialized countries often induced by exposure to tobacco smoke. A substantial number of patients with COPD also suffer from ...pulmonary hypertension that may be caused by hypoxia or other hypoxia-independent stimuli - inducing pulmonary vascular remodeling. The Ca(2+) binding protein, S100A4 is known to play a role in non-COPD-driven vascular remodeling of intrapulmonary arteries. Therefore, we have investigated the potential involvement of S100A4 in COPD induced vascular remodeling.
Lung tissue was obtained from explanted lungs of five COPD patients and five non-transplanted donor lungs. Additionally, mice lungs of a tobacco-smoke-induced lung emphysema model (exposure for 3 and 8 month) and controls were investigated. Real-time RT-PCR analysis of S100A4 and RAGE mRNA was performed from laser-microdissected intrapulmonary arteries. S100A4 immunohistochemistry was semi-quantitatively evaluated. Mobility shift assay and siRNA knock-down were used to prove hypoxia responsive elements (HRE) and HIF binding within the S100A4 promoter.
Laser-microdissection in combination with real-time PCR analysis revealed higher expression of S100A4 mRNA in intrapulmonary arteries of COPD patients compared to donors. These findings were mirrored by semi-quantitative analysis of S100A4 immunostaining. Analogous to human lungs, in mice with tobacco-smoke-induced emphysema an up-regulation of S100A4 mRNA and protein was observed in intrapulmonary arteries. Putative HREs could be identified in the promoter region of the human S100A4 gene and their functionality was confirmed by mobility shift assay. Knock-down of HIF1/2 by siRNA attenuated hypoxia-dependent increase in S100A4 mRNA levels in human primary pulmonary artery smooth muscle cells. Interestingly, RAGE mRNA expression was enhanced in pulmonary arteries of tobacco-smoke exposed mice but not in pulmonary arteries of COPD patients.
As enhanced S100A4 expression was observed in remodeled intrapulmonary arteries of COPD patients, targeting S100A4 could serve as potential therapeutic option for prevention of vascular remodeling in COPD patients.
Ca
is an important intracellular second messenger known to regulate several cellular functions. This research aimed to investigate the mechanisms of exercise-induced immunosuppression by measuring ...intracellular calcium levels, Ca
-regulating gene expression, and agonist-evoked proliferation of murine splenic T lymphocytes. Mice were randomly assigned to the control, sedentary group (C), and three experimental groups, which performed a single bout of intensive and exhaustive treadmill exercise. Murine splenic lymphocytes were separated by density-gradient centrifugation immediately (E0), 3h (E3), and 24h after exercise (E24). Fura-2/AM was used to monitor cytoplasmic free Ca
concentration in living cells. The combined method of carboxyfluorescein diacetate succinimidyl ester (CFSE) labeling and flow cytometry was used for the detection of T cell proliferation. The transcriptional level of Ca
-regulating genes was quantified by using qPCR. Both basal intracellular Ca
levels and agonist (ConA, OKT3, or thapsigargin)-induced Ca
transients were significantly elevated at E3 group (
<0.05 vs. control). However, mitogen-induced cell proliferation was significantly decreased at E3 group (
<0.05 vs. control). In parallel, the transcriptional level of plasma membrane Ca
-ATPases (PMCA), sarco/endoplasmic reticulum Ca
-ATPases (SERCA), TRPC1, and P2X7 was significantly downregulated, and the transcriptional level of IP
R2 and RyR2 was significantly upregulated in E3 (
<0.01 vs. control). In summary, this study demonstrated that acute exercise affected intracellular calcium homeostasis, most likely by enhancing transmembrane Ca
influx into cells and by reducing expression of Ca
-ATPases such as PMCA and SERCA. However, altered Ca
signals were not transduced into an enhanced T cell proliferation suggesting other pathways to be responsible for the transient exercise-associated immunosuppression.
Gamma cameras are of great interest due to their high potential in the field of Nuclear Medicine Imaging. They allow for an early diagnosis of reduced size tumors, and also for a wide variety of ...preclinical studies with the aim of designing more effective treatments against cancer. In this work we propose a significantly improved multi-pinhole collimator gamma camera and perform a first Monte Carlo analysis of its characteristics. Maintaining the configuration of a multi-pinhole collimator with a high degree of overlapping (thus with a high sensitivity), we add a new element, an active septa, that besides acting as a collimator, is able to measure the impact coordinates of the incident photon. This way one is able to unambiguously identify through which pinhole any gamma ray passes before being detected. The result is a high sensitivity and resolution multi-pinhole gamma camera with an arbitrarily large field of view. As a consequence, the final reconstructed image does not suffer from the undesired artifacts or truncation associated to the multiplexing phenomenon. In this study we focus on the development of a system able to visualize in 3D tumors, nodes and metastasis in real time in the operating room with very low dose. We also briefly analyse and propose a novel design for a Single Photon Emission Computed Tomography system.
Highly intense bunches of protons and ions with energies of several MeV/u can be generated with ultra-short laser pulses focused on solid targets. In the most common interaction regime, target normal ...sheath acceleration, the spectra of these particles are spread over a wide range following a Maxwellian distribution. We report on the design and testing of a magnetic chicane for the selection of protons within a limited energy window. This consisted of two successive, anti-parallel dipole fields generated by cost-effective permanent C-magnets with customized configuration and longitudinal positions. The chicane was implemented into the target vessel of a petawatt laser facility with constraints on the direction of the incoming laser beam and guidance of the outgoing particles through a vacuum port. The separation of protons and carbon ions within distinct energy intervals was demonstrated and compared to a ray tracing code. Measurements with radiochromic film stacks indicated the selection of protons within 2.4, 6.9 MeV, 5.0, 8.4 MeV, or ≥6.9 MeV depending on the lateral dispersion. A narrow peak at 4.8 MeV was observed with a time-of-flight detector.
The study aimed to investigate the effects of chronic moderate exercise on regulation of intracellular calcium signaling as an important link to proliferation capacity in murine splenic T ...lymphocytes.
Male CD1 Swiss mice were randomly assigned either to a control group (CG) or an exercise training group (EG). EG mice performed voluntary exercise for 3 months. Lymphocytes were isolated from murine spleens and intracellular calcium was determined by using Fura-2(AM) and fluorescence spectrometry. The combination of flow cytometry and carboxy-fluorescein succinimidyl ester labeling technique was used for determination of cell proliferation. The expression levels of Ca-regulating genes were determined by quantitative polymerase chain reaction (qPCR) analysis.
Basal Cai was significantly higher in mice from the EG compared with mice of the CG (P < 0.001, n = 6). Similarly, Cai transients after stimulation with phytohemagglutinin, concanavalin A, and the anti-CD3 antibody induced were significantly increased in mice from the EG (P < 0.05, n = 5). However, no differences were found after stimulation with thapsigargin (P < 0.05, n = 5). CD3 T cells from EG showed higher mitogen-induced proliferation levels than from CG (P < 0.05/0.01, n = 5). The mRNA expression of cellular Ca-regulating genes, such as STIM1, Cav2.3, TRPV4, IP3R2, ORAI1, MCU, TRPM5, and TRPC1, were significantly downregulated (P < 0.05/0.01, n = 5).
This study suggests that chronic moderate exercise improves intracellular Ca signaling in murine splenic lymphocytes. The enhanced availability of the second messenger Ca is followed by an improved cellular function such as cell proliferation. The downregulation of Ca homeostasis-related factor expression might be considered as a self-protective mechanism against elevated intracellular Ca signals.
To investigate whether NADPH oxidase 2 (NOX2), a major source of reactive oxygen species (ROS), contributes to the emergence of arterial hypertension in a murine model of sleep apnea.
Obstructive ...sleep apnea (OSA) is a risk factor for arterial hypertension and it is linked to oxidative stress.
C57BL/6J mice were exposed to chronic intermittent hypoxia (CIH) for 6 weeks (5 days/week, 8 h/day, alternating cycles of hypoxia and normoxia, each lasting 120 s, nadir FiO2: 7%). Blood pressure was monitored by telemetric catheters implanted into the abdominal aorta. Pharmacological inhibition of NOX by apocynin and NOX2-deficient mice were used to assess the role of NOX in CIH-induced arterial hypertension. NOX2 gene expression was measured by real-time PCR in different cardiovascular tissues.
When compared with room air conditions, wild-type mice showed significant blood pressure elevations after exposure to CIH. This response was attenuated after treating animals with apocynin and in NOX2 (=gp91) knockout mice, whereas NOX2 was not upregulated in the heart, aorta, and femoral/carotid arteries of CIH mice.
We suggest that the CIH-induced arterial hypertension is mediated by ROS derived from an activation of NOX2 within cells located outside the cardiovascular system.
Background: Sestrin 2 is a redox-dependent repressor of Pdgfrβ signaling and thereby interferes with lung injury repair.
Results: Sestrin 2 is a positive regulator of proteasomal function and ...activates transcription of Nrf2-regulated antioxidant genes.
Conclusion: Sestrin 2 is a component of a novel Sestrin 2/Pdgfrβ repressor pathway.
Significance: The Sestrin2/Pdgfrβ repressor pathway is likely to play role in the pathogenesis of chronic obstructive pulmonary disease (COPD).
We recently identified the antioxidant protein Sestrin 2 (Sesn2) as a suppressor of platelet-derived growth factor receptor β (Pdgfrβ) signaling and Pdgfrβ signaling as an inducer of lung regeneration and injury repair. Here, we identified Sesn2 and the antioxidant gene inducer nuclear factor erythroid 2-related factor 2 (Nrf2) as positive regulators of proteasomal function. Inactivation of Sesn2 or Nrf2 induced reactive oxygen species-mediated proteasomal inhibition and Pdgfrβ accumulation. Using bacterial artificial chromosome (BAC) transgenic HeLa and mouse embryonic stem cells stably expressing enhanced green fluorescent protein-tagged Sesn2 at nearly endogenous levels, we also showed that Sesn2 physically interacts with 2-Cys peroxiredoxins and Nrf2 albeit under different reductive conditions. Overall, we characterized a novel, redox-sensitive Sesn2/Pdgfrβ suppressor pathway that negatively interferes with lung regeneration and is up-regulated in the emphysematous lungs of patients with chronic obstructive pulmonary disease (COPD).
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