Nitric oxide stimulates interleukin-6 production in skeletal myotubes

Strenuous exercise leads to the up-regulation of interleukin-6 (IL-6) production and enhanced nitric oxide (NO) release within the contracting skeletal muscles. In this study, we investigated whether NO regulates IL-6 production in C2C12 myotubes. These cells exhibited a concentration-dependent increase in IL-6 production upon stimulation with NO donors (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA-NONOate), (Z)-1-[N-(3-aminopropyl)-N-(n-propyl)amino]diazen-1-ium-1,2-diolate (PAPA-NONOate), and sodium nitroprusside (SNP). This treatment did not alter cGMP levels nor did the soluble guanylyl cyclase (sGC) inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one(ODQ), alter this response. The NO-independent sGC activator 5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]-pyrimidin-4-ylamine (BAY41-2272) and cyclic guanosine monophosphate (cGMP) analog 8Br-cGMP failed to induce IL-6 production. Upon exposure to NO donors, we observed an increase in Erk1/2 and p38 MAPK phosphorylation but not in SAPK/JNK. In addition, NO-induced IL-6 release was inhibited in a concentration-dependent fashion by the MEK1/2 inhibitor PD98059 and the p38 MAPK inhibitor SB203580 but not by the SAPK/JNK inhibitor SP600125. We conclude that NO-stimulated IL-6 production in differentiated C2C12 myotubes is cGMP-independent and mediated by activation of MAPK pathways.

PKG-I inhibition attenuates vascular endothelial growth factor-stimulated angiogenesis

Vascular endothelial growth factor (VEGF) stimulates nitric oxide (NO) production, which mediates many of its angiogenic actions. However, the angiogenic pathways that operate downstream of NO following VEGF treatment are not well characterized. Herein, we used DT-2 and DT-3, two highly selective cGMP-dependent protein kinase I peptide inhibitors to determine the contribution of PKG-I in VEGF-stimulated angiogenesis. Incubation of chicken chorioallantoic membranes (CAM) with PKG-I peptide inhibitors decreased vascular length in a dose-dependent manner, with DT-3 being more effective than DT-2. Moreover, inhibition of PKG-I with DT-3 abolished the angiogenic response elicited by VEGF in the rabbit eye cornea. PKG-I inhibition also blocked VEGF-stimulated vascular leakage. In vitro, treatment of cells with VEGF stimulated phosphorylation of the PKG substrate VASP through VEGFR2 activation; the VEGF-stimulated VASP phosphorylation was reduced by DT-2. Pre-treatment of cells with DT-2 or DT-3 inhibited VEGF-stimulated mitogen-activated protein kinase cascades (ERK1/2 and p38), growth, migration and sprouting of endothelial cells. The above observations taken together identify PKG-I as a downstream effector of VEGFR2 in EC and provide a rational basis for the use of PKG-I inhibitors in disease states characterized by excessive neovascularization.

Pulmonary function tests, sputum induction, and bronchial provocation tests: diagnostic tools in the challenge of distinguishing asthma and COPD phenotypes in clinical practice

BACKGROUND

despite a number of important differences in the pathogenesis, course, and prognosis, asthma and chronic obstructive pulmonary disease (COPD) have many features in common. Furthermore, smoking induces considerable overlap in pathogenesis and clinical features between these conditions. This study aimed to reveal what inflammatory patterns prevail in clinically established diagnosis groups, including overlap phenotypes of asthma and COPD, and to evaluate the correlation with airway reversibility and hyperreactivity in these overlapping conditions.

METHODS

a total of 110 patients (17 healthy subjects; 16 "healthy" smokers; 46 asthma patients: 24 smokers and 22 non-smokers; and 31 COPD patients: 10 COPD patients with reversibility and 21 without) participated in the study. Induced sputum, reversibility testing, methacholine and adenosine 5'monophosphate (AMP) provocation challenges, and skin prick testing were performed. Airways inflammation was assessed by differential cell counts, and cytokines (interleukin-8 [IL-8] and tumor necrosis factor-alpha [TNF-α]) were measured in induced sputum by enzyme-linked immunosorbent assay (ELISA).

RESULTS

COPD patients with reversibility had increased sputum neutrophils, IL-8, and TNF-α levels compared to smoking asthmatics. No difference was found in inflammatory cells and cytokines between COPD subgroups. Sputum neutrophilia was inversely correlated with the change in forced expiratory volume in one second (ΔFEV(1)) in smoking asthmatic patients (r = -0.563, P = 0.036). No correlation was found between airway hyperresponsiveness (AHR), either with methacholine or AMP, and inflammation in asthmatic patients, regardless of smoking. Reversibility was not correlated with inflammation in COPD patients. However, the response to AMP challenge was correlated with sputum neutrophils (r = 0.844, P = 0.001).

CONCLUSION

although overlaps exist in the disease characteristics of asthma and COPD, the combination of lung function testing, sputum induction, and AHR reveals information that facilitates the distinction between these diseases, allowing clinicians to better tailor their therapy.

Allergic inflammation does not impact chemical-induced carcinogenesis in the lungs of mice

BACKGROUND

Although the relationship between allergic inflammation and lung carcinogenesis is not clearly defined, several reports suggest an increased incidence of lung cancer in patients with asthma. We aimed at determining the functional impact of allergic inflammation on chemical carcinogenesis in the lungs of mice.

METHODS

Balb/c mice received single-dose urethane (1 g/kg at day 0) and two-stage ovalbumin during tumor initiation (sensitization: days -14 and 0; challenge: daily at days 6-12), tumor progression (sensitization: days 70 and 84; challenge: daily at days 90-96), or chronically (sensitization: days -14 and 0; challenge: daily at days 6-12 and thrice weekly thereafter). In addition, interleukin (IL)-5 deficient and wild-type C57BL/6 mice received ten weekly urethane injections. All mice were sacrificed after four months. Primary end-points were number, size, and histology of lung tumors. Secondary end-points were inflammatory cells and mediators in the airspace compartment.

RESULTS

Ovalbumin provoked acute allergic inflammation and chronic remodeling of murine airways, evident by airspace eosinophilia, IL-5 up-regulation, and airspace enlargement. Urethane resulted in formation of atypical alveolar hyperplasias, adenomas, and adenocarcinomas in mouse lungs. Ovalbumin-induced allergic inflammation during tumor initiation, progression, or continuously did not impact the number, size, or histologic distribution of urethane-induced pulmonary neoplastic lesions. In addition, genetic deficiency in IL-5 had no effect on urethane-induced lung tumorigenesis.

CONCLUSIONS

Allergic inflammation does not impact chemical-induced carcinogenesis of the airways. These findings suggest that not all types of airway inflammation influence lung carcinogenesis and cast doubt on the idea of a mechanistic link between asthma and lung cancer.

In vivo expression of innate immunity markers in patients with Mycobacterium tuberculosis infection

Background

Toll-like receptors (TLRs), Coronin-1 and Sp110 are essential factors for the containment of Mycobacterium tuberculosis infection. The purpose of this study was to investigate the in vivo expression of these molecules at different stages of the infection and uncover possible relationships between these markers and the state of the disease.

Methods

Twenty-two patients with active tuberculosis, 15 close contacts of subjects with latent disease, 17 close contacts of subjects negative for mycobacterium antigens and 10 healthy, unrelated to patients, subjects were studied. Quantitative mRNA expression of Coronin-1, Sp110, TLRs-1,-2,-4 and -6 was analysed in total blood cells vs an endogenous house-keeping gene.

Results

The mRNA expression of Coronin-1, Sp110 and TLR-2 was significantly higher in patients with active tuberculosis and subjects with latent disease compared to the uninfected ones. Positive linear correlation for the expression of those factors was only found in the infected populations.

Conclusions

Our results suggest that the up-regulation of Coronin-1 and Sp110, through a pathway that also includes TLR-2 up-regulation may be involved in the process of tuberculous infection in humans. However, further studies are needed, in order to elucidate whether the selective upregulation of these factors in the infected patients could serve as a specific molecular marker of tuberculosis.

Hydrogen sulfide is an endogenous inhibitor of phosphodiesterase activity

OBJECTIVE

Recent studies have demonstrated that hydrogen sulfide (H(2)S) is produced within the vessel wall from L-cysteine regulating several aspects of vascular homeostasis. H(2)S generated from cystathione γ-lyase (CSE) contributes to vascular tone; however, the molecular mechanisms underlying the vasorelaxing effects of H(2)S are still under investigation.

METHODS AND RESULTS

Using isolated aortic rings, we observed that addition of L-cysteine led to a concentration-dependent relaxation that was prevented by the CSE inhibitors DL-propargylglyicine (PAG) and β-cyano-l-alanine (BCA). Moreover, incubation with PAG or BCA resulted in a rightward shift in sodium nitroprusside-and isoproterenol-induced relaxation. Aortic tissues exposed to PAG or BCA contained lower levels of cGMP, exposure of cells to exogenous H(2)S or overexpression of CSE raised cGMP concentration. RNA silencing of CSE expression reduced intracellular cGMP levels confirming a positive role for endogenous H(2)S on cGMP accumulation. The ability of H(2)S to enhance cGMP levels was greatly reduced by the nonselective phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. Finally, addition of H(2)S to a cell-free system inhibited both cGMP and cAMP breakdown.

CONCLUSIONS

These findings provide direct evidence that H(2)S acts as an endogenous inhibitor of phosphodiesterase activity and reinforce the notion that this gasotransmitter could be therapeutically exploited.

Intercostal muscle blood flow limitation during exercise in chronic obstructive pulmonary disease

RATIONALE

It has been hypothesized that, because of the high work of breathing sustained by patients with chronic obstructive pulmonary disease (COPD) during exercise, blood flow may increase in favor of the respiratory muscles, thereby compromising locomotor muscle blood flow.

OBJECTIVES

To test this hypothesis by investigating whether, at the same work of breathing, intercostal muscle blood flow during exercise is as high as during resting isocapnic hyperpnea when respiratory and locomotor muscles do not compete for the available blood flow.

METHODS

Intercostal and vastus lateralis muscle perfusion was measured simultaneously in 10 patients with COPD (FEV₁ = 50.5 ± 5.5% predicted) by near-infrared spectroscopy using indocyanine green dye.

MEASUREMENTS AND MAIN RESULTS

Measurements were made at several exercise intensities up to peak work rate (WRpeak) and subsequently during resting hyperpnea at minute ventilation levels up to those at WRpeak. During resting hyperpnea, intercostal muscle blood flow increased with the power of breathing to 11.4 ± 1.6 ml/min per 100 g at the same ventilation recorded at WRpeak. Conversely, during graded exercise, intercostal muscle blood flow remained unchanged from rest up to 50% WRpeak (6.8 ± 1.3 ml/min per 100 g) and then fell to 4.5 ± 0.8 ml/min per 100 g at WRpeak (P = 0.003). Cardiac output plateaued above 50% WRpeak (8.4 ± 0.1 l/min), whereas vastus lateralis muscle blood flow increased progressively, reaching 39.8 ± 7.1 ml/min per 100 g at WRpeak.

CONCLUSIONS

During intense exercise in COPD, restriction of intercostal muscle perfusion but preservation of quadriceps muscle blood flow along with attainment of a plateau in cardiac output represents the inability of the circulatory system to satisfy the energy demands of locomotor and respiratory muscles.

MRC chronic Dyspnea Scale: Relationships with cardiopulmonary exercise testing and 6-minute walk test in idiopathic pulmonary fibrosis patients: a prospective study

Background

Exertional dyspnea is the most prominent and disabling feature in idiopathic pulmonary fibrosis (IPF). The Medical Research Chronic (MRC) chronic dyspnea score as well as physiological measurements obtained during cardiopulmonary exercise testing (CPET) and the 6-minute walk test (6MWT) are shown to provide information on the severity and survival of disease.

Methods

We prospectively recruited IPF patients and examined the relationship between the MRC score and either CPET or 6MWT parameters known to reflect physiologic derangements limiting exercise capacity in IPF patients

Results

Twenty-five patients with IPF were included in the study. Significant correlations were found between the MRC score and the distance (r = -.781, p < 0.001), the SPO₂ at the initiation and the end (r = -.542, p = 0.005 and r = -.713, p < 0.001 respectively) and the desaturation index (r = .634, p = 0.001) for the 6MWT; the MRC score and VO₂ peak/kg (r = -.731, p < 0.001), SPO₂ at peak exercise (r = -. 682, p < 0.001), VE/VCO₂ slope (r = .731, p < 0.001), VE/VCO₂ at AT (r = .630, p = 0.002) and the Borg scale at peak exercise (r = .50, p = 0.01) for the CPET. In multiple logistic regression analysis, the only variable independently related to the MRC is the distance walked at the 6MWT.

Conclusion

In this population of IPF patients a good correlation was found between the MRC chronic dyspnoea score and physiological parameters obtained during maximal and submaximal exercise testing known to reflect ventilatory impairment and exercise limitation as well as disease severity and survival. This finding is described for the first time in the literature in this group of patients as far as we know and could explain why a simple chronic dyspnea score provides reliable prognostic information on IPF.

Expiratory muscle loading increases intercostal muscle blood flow during leg exercise in healthy humans

We investigated whether expiratory muscle loading induced by the application of expiratory flow limitation (EFL) during exercise in healthy subjects causes a reduction in quadriceps muscle blood flow in favor of the blood flow to the intercostal muscles. We hypothesized that, during exercise with EFL quadriceps muscle blood flow would be reduced, whereas intercostal muscle blood flow would be increased compared with exercise without EFL. We initially performed an incremental exercise test on eight healthy male subjects with a Starling resistor in the expiratory line limiting expiratory flow to approximately 1 l/s to determine peak EFL exercise workload. On a different day, two constant-load exercise trials were performed in a balanced ordering sequence, during which subjects exercised with or without EFL at peak EFL exercise workload for 6 min. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle blood flow index (BFI) was calculated by near-infrared spectroscopy using indocyanine green, whereas cardiac output (CO) was measured by an impedance cardiography technique. At exercise termination, CO and stroke volume were not significantly different during exercise, with or without EFL (CO: 16.5 vs. 15.2 l/min, stroke volume: 104 vs. 107 ml/beat). Quadriceps muscle BFI during exercise with EFL (5.4 nM/s) was significantly (P = 0.043) lower compared with exercise without EFL (7.6 nM/s), whereas intercostal muscle BFI during exercise with EFL (3.5 nM/s) was significantly (P = 0.021) greater compared with that recorded during control exercise (0.4 nM/s). In conclusion, increased respiratory muscle loading during exercise in healthy humans causes an increase in blood flow to the intercostal muscles and a concomitant decrease in quadriceps muscle blood flow.

Comparison of high-frequency oscillation and tracheal gas insufflation versus standard high-frequency oscillation at two levels of tracheal pressure

PURPOSE

In acute respiratory distress syndrome (ARDS), combined high-frequency oscillation (HFO) and tracheal gas insufflation (TGI) may improve oxygenation through a TGI-induced increase in mean tracheal pressure (P(tr)). We compared standard HFO and HFO-TGI matched for P(tr), in order to determine whether TGI affects gas exchange independently from P (tr).

METHODS

We conducted a prospective, randomized, crossover, physiological study in a 37-bed intensive care unit. Twenty-two patients with early acute lung injury (ALI) or ARDS were enrolled. On day 1, patients were ventilated with HFO, without (60 min) and combined with TGI (60 min) in random order. HFO/HFO-TGI sessions were repeated in inverse order within 7 h. HFO/HFO-TGI mean airway pressure (P(aw)) was titrated to a P(tr) that was either equal to (low P(aw)) or 3 cmH(2)O higher than (high P(aw)) the P(tr) of the preceding conventional mechanical ventilation. On day 2, the protocol was repeated at the alternative P(tr) level relative to day 1.

RESULTS

Gas exchange and hemodynamics were determined before, during, and after HFO/HFO-TGI sessions. HFO-TGI-high P(aw) versus HFO-high P(aw) resulted in significantly higher PaO(2)/inspired O(2) fraction (FiO(2)) [mean +/- standard error of the mean (SEM): 281.6 +/- 15.1 versus 199.0 +/- 15.0 mmHg; mean increase: 42%; P < 0.001]. HFO-TGI-low P(aw), versus HFO-low P(aw), resulted in significantly higher PaO(2)/FiO(2) (222.8 +/- 14.6 versus 141.3 +/- 8.7 mmHg; mean increase: 58%; P < 0.001). PaCO(2) was significantly lower during HFO-TGI-high P(aw) versus HFO-high P(aw) (45.3 +/- 1.6 versus 53.7 +/- 1.9 mmHg; mean decrease: 16%; P = 0.037).

CONCLUSIONS

At the same P(tr) level, HFO-TGI results in superior gas exchange compared with HFO.

Carbapenem-resistant versus carbapenem-susceptible Acinetobacter baumannii bacteremia in a Greek intensive care unit: risk factors, clinical features and outcomes

BACKGROUND

There has been an increasing incidence of carbapenem-resistant Acinetobacter baumannii (CRAB) infections in recent years. The objective of this study was to determine specific risk factors for and outcome of bacteremia due to CRAB isolates among our ICU patients with A. baumannii bacteremia.

PATIENTS AND METHODS

Among 96 patients with ICU-acquired A. baumannii bacteremia, 30 patients with CRAB were compared with the remaining 66 with carbapenem-susceptible A. baumannii (CSAB) isolates.

RESULTS

Recent ventilator-associated pneumonia (VAP) due to CRAB (OR 16.74, 95% CI 3.16-88.79, p = 0.001) and a greater number of intravascular devices (OR 3.93, 95% CI 1.9-13.0, p = 0.025) were independently associated with CRAB bacteremia acquisition. Patients with CRAB bacteremia had a lower severity of illness on admission than those with CSAB. Although, by univariate analysis, patients with CRAB were more likely to have had exposure to colistin, carbapenems and linezolid, multivariate analysis did not revealed any significant association. The mortality was not different between patients with CRAB and CSAB bacteremia (43.3 vs. 46.9%, p = 0.740). Severity of organ failure (OR 1.42, 95% CI 1.20-1.67, p = 0.001), and increased white blood cell (WBC) count (OR 1.09, 95% CI 1.01-1.19, p = 0.036), at bacteremia onset were independently associated with mortality.

CONCLUSION

VAP due to CRAB and excess use of intravascular devices are the most important risk factors for CRAB bacteremia in our ICU. Severity of organ failure and WBC count at A. baumannii bacteremia onset are independently associated with mortality.

Specific effects of bortezomib against experimental malignant pleural effusion: a preclinical study

Background

We have previously shown that nuclear factor (NF)-κB activation of mouse Lewis lung carcinoma (LLC) specifically promotes the induction of malignant pleural effusions (MPE) by these cells. In the present studies we hypothesized that treatment of immunocompetent mice with bortezomib tailored to inhibit cancer cell NF-κB activation and not proliferation specifically inhibits MPE formation by LLC cells.

Results

Treatment of LLC cells with low concentrations of bortezomib (100 ng/ml) inhibited NF-κB activation and NF-κB-dependent transcription, but not cellular proliferation. Bortezomib treatment of immunocompetent C57BL/6 mice bearing LLC-induced subcutaneous tumors and MPEs significantly blocked tumor-specific NF-κB activation. However, bortezomib treatment did not impair subcutaneous LLC tumor growth, but was effective in limiting LLC-induced MPE. This specific effect was evidenced by significant reductions in effusion accumulation and the associated mortality and was observed with both preventive (beginning before MPE formation) and therapeutic (beginning after MPE establishment) bortezomib treatment. The favorable impact of bortezomib on MPE was associated with suppression of cardinal MPE-associated phenomena, such as inflammation, vascular hyperpermeability, and angiogenesis. In this regard, therapeutic bortezomib treatment had identical favorable results on MPE compared with preventive treatment, indicating that the drug specifically counteracts effusion formation.

Conclusions

These studies indicate that proteasome inhibition tailored to block NF-κB activation of lung adenocarcinoma specifically targets the effusion-inducing phenotype of this tumor. Although the drug has limited activity against advanced solid lung cancer, it may prove beneficial for patients with MPE.

Effectiveness of pharmacotherapy and behavioral interventions for smoking cessation in actual clinical practice

OBJECTIVES

This study evaluated the effectiveness of behavioral interventions (brief counseling, nonspecific psychological support in groups - NSGS and cognitive behavioral group therapy - CBGT) in combination with bupropion SR for smoking cessation in the field, through a smoking cessation clinic.

METHODS

Two-hundred-and-five smokers were enrolled in a 19-week course during 2007/ 2008, and were randomly assigned to: bupropion SR combined with brief counseling (group A), bupropion SR combined with NSGS (group B), bupropion SR combined with CBGT (group C), or CBGT as the only approach (group D).

RESULTS

Continuous abstinence rates at the end of therapy were 53.2% for group A, 62.9% for group B, 50.0% for group C, and 22.2% (p < 0.05) for group D. Sustained abstinence rates in 12 months were 29.6%, 28.1%, 34.3% and 19.4% (p > 0.05), respectively.

CONCLUSIONS

Bupropion SR is an effective aid for smoking cessation in clinical practice. NSGT increased the chances for success at the end of therapy when combined with bupropion SR, while CBGT as monotherapy was less effective compared with the approaches including pharmacotherapy. It is suggested that smoking cessation interventions in real-life healthcare settings should be implemented through comprehensive programs using pharmacotherapy where applicable, combined with NSGT, and integrated by specialized healthcare professionals.

Exhaled nitric oxide and exhaled breath condensate pH in severe refractory asthma

BACKGROUND

Distinct inflammatory cellular phenotypes of severe refractory asthma (SRA) have been reported. Fractional exhaled nitric oxide (FeNO) primarily is related to eosinophilic inflammation. Exhaled breath condensate (EBC) pH has been suggested as a noninvasive tool in the assessment of patients with asthma. We sought to determine whether FeNO and EBC pH could identify the presence and type of the underlying cellular inflammation in patients with SRA.

METHODS

Twenty-nine patients with SRA, 27 patients with moderate asthma, and 17 healthy subjects underwent FeNO measurement, EBC collection for pH measurement, and sputum induction for cell count identification.

RESULTS

FeNO was significantly higher and pH significantly lower in patients with SRA than in the other groups. In SRA, FeNO levels of > 19 parts per billion were associated with a sensitivity of 0.78 and a specificity of 0.73 for sputum eosinophilia, whereas FeNO levels of < 19 parts per billion were associated with a sensitivity of 0.63 and a specificity of 0.9 for sputum neutrophilia irrespective of the presence of eosinophils. The pH failed to predict the cellular profile in SRA, but a cutoff value of < 7.37 could predict sputum eosinophilia in moderate asthma.

CONCLUSIONS

In patients with SRA, different FeNO threshold values can identify those with predominant eosinophilia as well as those with neutrophilia. FeNO levels were reduced in patients with predominant neutrophilia regardless of the concomitant presence of eosinophilia. Although pH could not identify the cellular profile in SRA, it seemed to be a better index for predicting eosinophilia in moderate asthma.

Near-infrared spectroscopy and indocyanine green derived blood flow index for noninvasive measurement of muscle perfusion during exercise

Near-infrared spectroscopy (NIRS) with the tracer indocyanine green (ICG) may be used for measuring muscle blood flow (MBF) during exercise, if arterial ICG concentration is measured simultaneously. Although pulse dye densitometry allows for noninvasive measurement of arterial dye concentration, this technique is sensitive to motion and may not be applicable during exercise. The aim of this study was to evaluate a noninvasive blood flow index (BFI), which is derived solely from the muscle ICG concentration curve. In 10 male cyclists 5 mg ICG were injected into an antecubital vein at rest and during cycling at 30, 60, 70, 80, 90, and 100% of previously determined maximal work load. Simultaneously blood was withdrawn through a photodensitometer at 20 ml/min from the radial artery to measure arterial ICG concentration. To measure muscle tissue ICG concentrations, two sets of NIRS optodes were positioned on the skin, one over the left seventh intercostal space and the other over the left vastus lateralis muscle. MBF was calculated from the arterial and muscle concentration data according to Fick's principle. BFI was calculated solely from the muscle concentration curve as ICG concentration difference divided by rise time between 10 and 90% of peak. During exercise mean BFI values changed similarly to MBF in both intercostal and quadriceps muscles and showed excellent correlations with MBF: r = 0.98 and 0.96, respectively. Individual data showed some scattering among BFI and MBF values but still reasonable correlations of BFI with MBF: r = 0.73 and 0.72 for intercostal and quadriceps muscles, respectively. Interobserver variability, as analyzed by Bland-Altman plots, was considerably less for BFI than MBF. These data suggest that BFI can be used for measuring changes in muscle perfusion from rest to maximal exercise. Although absolute blood flow cannot be determined, BFI has the advantages of being essentially noninvasive and having low interobserver variability.

The soluble guanylyl cyclase inhibitor NS-2028 reduces vascular endothelial growth factor-induced angiogenesis and permeability

Nitric oxide (NO) is known to promote vascular endothelial growth factor (VEGF)-stimulated permeability and angiogenesis. However, effector molecules that operate downstream of NO in this pathway remain poorly characterized. Herein, we determined the effect of soluble guanylyl cyclase (sGC) inhibition on VEGF responses in vitro and in vivo. Treatment of endothelial cells (EC) with VEGF stimulated eNOS phosphorylation and cGMP accumulation; pretreatment with the sGC inhibitor 4H-8-bromo-1,2,4-oxadiazolo(3,4-d)benz(b)(1,4)oxazin-1-one (NS-2028) blunted cGMP levels without affecting VEGF-receptor phosphorylation. Incubation of cells with NS-2028 blocked the mitogenic effects of VEGF. In addition, cells in which sGC was inhibited exhibited no migration and sprouting in response to VEGF. To study the mechanisms through which NS-2028 inhibits EC migration, we determined the effects of alterations in cGMP levels on p38 MAPK. Initially, we observed that inhibition of sGC attenuated VEGF-stimulated activation of p38. In contrast, the addition of 8-Br-cGMP to EC stimulated p38 phosphorylation. The addition of cGMP elevating agents (BAY 41-2272, DETA NO and YC-1) enhanced EC migration. To test whether sGC also mediated the angiogenic effects of VEGF in vivo, we used the rabbit cornea assay. Animals receiving NS-2028 orally displayed a reduced angiogenic response to VEGF. As increased vascular permeability occurs prior to new blood vessel formation, we determined the effect of NS-2028 in vascular leakage. Using a modified Miles assay, we observed that NS-2028 attenuated VEGF-induced permeability. Overall, we provide evidence that sGC mediates the angiogenic and permeability-promoting activities of VEGF, indicating the significance of sGC as a downstream effector of VEGF-triggered responses.

A transcriptomic computational analysis of mastic oil-treated Lewis lung carcinomas reveals molecular mechanisms targeting tumor cell growth and survival

Background

Mastic oil from Pistacia lentiscus variation chia, a blend of bioactive terpenes with recognized medicinal properties, has been recently shown to exert anti-tumor growth activity through inhibition of cancer cell proliferation, survival, angiogenesis and inflammatory response. However, no studies have addressed its mechanisms of action at genome-wide gene expression level.

Methods

To investigate molecular mechanisms triggered by mastic oil, Lewis Lung Carcinoma cells were treated with mastic oil or DMSO and RNA was collected at five distinct time points (3-48 h). Microarray expression profiling was performed using Illumina mouse-6 v1 beadchips, followed by computational analysis. For a number of selected genes, RT-PCR validation was performed in LLC cells as well as in three human cancer cell lines of different origin (A549, HCT116, K562). PTEN specific inhibition by a bisperovanadium compound was applied to validate its contribution to mastic oil-mediated anti-tumor growth effects.

Results

In this work we demonstrated that exposure of Lewis lung carcinomas to mastic oil caused a time-dependent alteration in the expression of 925 genes. GO analysis associated expression profiles with several biological processes and functions. Among them, modifications on cell cycle/proliferation, survival and NF-κB cascade in conjunction with concomitant regulation of genes encoding for PTEN, E2F7, HMOX1 (up-regulation) and NOD1 (down-regulation) indicated some important mechanistic links underlying the anti-proliferative, pro-apoptotic and anti-inflammatory effects of mastic oil. The expression profiles of Hmox1, Pten and E2f7 genes were similarly altered by mastic oil in the majority of test cancer cell lines. Inhibition of PTEN partially reversed mastic oil effects on tumor cell growth, indicating a multi-target mechanism of action. Finally, k-means clustering, organized the significant gene list in eight clusters demonstrating a similar expression profile. Promoter analysis in a representative cluster revealed shared putative cis-elements suggesting a common regulatory transcription mechanism.

Conclusions

Present results provide novel evidence on the molecular basis of tumor growth inhibition mediated by mastic oil and set a rational basis for application of genomics and bioinformatic methodologies in the screening of natural compounds with potential cancer chemopreventive activities.

Impairment of autonomic nervous system activity in patients with pulmonary arterial hypertension: a case control study

BACKGROUND

Chronotropic response to exercise (CR) and heart rate recovery (HRR) immediately after exercise are indirect indices of sympathetic and parasympathetic activity, respectively. The aim of this study was to evaluate CR and HRR in patients with pulmonary arterial hypertension (PAH) in relation to disease severity.

METHODS AND RESULTS

Ten PAH patients (6 females/4 males, mean age: 48+/-12 years) and 10 control subjects matched for age, gender, and body mass index (6 females/4 males, mean age: 46+/-6 years) performed a ramp incremental symptom-limited cardiopulmonary exercise test on a cycle ergometer. Main measurements included heart rate at rest (HR), CR=[(peak HR-resting HR/220-age-resting HR)x100, %], HRR(1)=HR difference from peak exercise to 1minute after, ventilatory efficiency during exercise (VE/VCO(2) slope), peak oxygen uptake (VO(2)p), and the first-degree slope of VO(2) for the first minute of the recovery period (VO(2)/t-slope). PAH patients had a significantly decreased CR (58+/-31 vs 92+/-13, %, P < .001) and HRR(1) (10+/-5 vs 29+/-6, beats/min, P < .001) as well as VO(2)p (11.9+/-3.5 vs 26.9+/-6.6, mL.kg.min) and VO(2)/t-slope (0.2+/-0.1 vs. 0.9+/-0.2, mL.kg.min(2)) compared with controls. CR and HRR(1) correlated well with VO(2)p (r=0.7; P < .001 and r=0.85; P < .001, respectively) and VO(2)/t-slope (r=0.66; P < .001 and r=0.85; P < .001, respectively) and had a significant inverse correlation with VE/VCO(2) slope (r=-0.47; P < .01 and r=-0.77; P < .001, respectively).

CONCLUSIONS

PAH patients present a significant impairment of CR and HRR(1) in relation to disease severity, indicating profound autonomic nervous system abnormalities.

Physical exercise improves the peripheral microcirculation of patients with chronic heart failure

PURPOSE

Patients with chronic heart failure (CHF) present with microcirculation alterations, partially attributed to endothelial dysfunction. Exercise training has been shown to induce beneficial effects in CHF patients. The aim of our study was to assess the effect of physical exercise on the microcirculation of CHF patients by near-infrared spectroscopy (NIRS).

METHODS

Sixteen consecutive stable CHF patients (men, n = 10; mean age = 50 +/- 12 years) participated in a 3-month rehabilitation program (3 sessions per week). All patients performed symptom-limited, ramp-incremental cardiopulmonary exercise testing on a cycle ergometer before and after the completion of the program. Measurements included peak oxygen uptake (VO2peak), VO2 at anaerobic threshold (AT), and first-degree slope of VO2 during the first minute of recovery (VO2/t slope). Tissue oxygen saturation was continuously measured by NIRS at the thenar muscle during a 3-minute vascular occlusion with a pneumatic cuff (occlusion technique) before and after the rehabilitation program.

RESULTS

The oxygen reperfusion rate (%/min) following the release of vascular occlusion increased significantly after the rehabilitation program (450 +/- 105 to 532 +/- 151, P = .004) as did vascular reactivity (from 27 +/- 13%/min to 39 +/- 21%/min, P = .006). In addition, there was a significant increase in VO2peak and AT (from 14.3 +/- 4.7 mL . kg . min to 16.7 +/- 6.3 mL . kg . min and from 9.5 +/- 3.6 mL . kg . min to 11.3 +/- 4 mL . kg . min, P = .007 and P = .012, respectively) as well as in VO2/t slope (from 0.35 +/- 0.17 to 0.51 +/- 0.07 mL . kg . min, P = .005).

CONCLUSIONS

Peripheral microcirculation of CHF patients measured by NIRS improved after the rehabilitation program. NIRS is a noninvasive technique that could be used to evaluate the effect of rehabilitation on the peripheral microcirculation of CHF patients.

Electrical muscle stimulation preserves the muscle mass of critically ill patients: a randomized study

Introduction

Critically ill patients are characterized by increased loss of muscle mass, partially attributed to sepsis and multiple organ failure, as well as immobilization. Recent studies have shown that electrical muscle stimulation (EMS) may be an alternative to active exercise in chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) patients with myopathy. The aim of our study was to investigate the EMS effects on muscle mass preservation of critically ill patients with the use of ultrasonography (US).

Methods

Forty-nine critically ill patients (age: 59 ± 21 years) with an APACHE II admission score ≥13 were randomly assigned after stratification upon admission to receive daily EMS sessions of both lower extremities (EMS-group) or to the control group (control group). Muscle mass was evaluated with US, by measuring the cross sectional diameter (CSD) of the vastus intermedius and the rectus femoris of the quadriceps muscle.

Results

Twenty-six patients were finally evaluated. Right rectus femoris and right vastus intermedius CSD decreased in both groups (EMS group: from 1.42 ± 0.48 to 1.31 ± 0.45 cm, P = 0.001 control group: from 1.59 ± 0.53 to 1.37 ± 0.5 cm, P = 0.002; EMS group: from 0.91 ± 0.39 to 0.81 ± 0.38 cm, P = 0.001 control group: from 1.40 ± 0.64 to 1.11 ± 0.56 cm, P = 0.004, respectively). However, the CSD of the right rectus femoris decreased significantly less in the EMS group (-0.11 ± 0.06 cm, -8 ± 3.9%) as compared to the control group (-0.21 ± 0.10 cm, -13.9 ± 6.4%; P < 0.05) and the CSD of the right vastus intermedius decreased significantly less in the EMS group (-0.10 ± 0.05 cm, -12.5 ± 7.4%) as compared to the control group (-0.29 ± 0.28 cm, -21.5 ± 15.3%; P < 0.05).

Conclusions

EMS is well tolerated and seems to preserve the muscle mass of critically ill patients. The potential use of EMS as a preventive and rehabilitation tool in ICU patients with polyneuromyopathy needs to be further investigated.

Trial Registration

clinicaltrials.gov: NCT00882830