Acute Respiratory Distress Syndrome: Role of Oleic Acid-Triggered Lung Injury and Inflammation

Plasma Saturated and Monounsaturated Fatty Acids in Behçet's Disease

Background:

Fatty Acid (FA) composition of serum has been associated with many markers of inflammation. In this study, we tried to examine plasma Saturated Fatty Acid (SFA) and Monounsaturated Fatty Acid (MUFA) composition in Behçet's Disease (BD) patients. The associations between the circulating FA levels and some markers of inflammation have also been investigated.

Methods:

This study is a cross-sectional one. In fact, a total of 101 BD patients and healthy controls group of 99 subjects are enrolled. Gas Chromatograph equipped with a Capillary Split/Splitless Injector and flame ionization detector was used to analyze the plasma SFA and MUFA compositions. The high sensitivity C-Reactive Protein (hsCRP) and fibrinogen levels were measured using standard techniques.

Results:

BD patients had significantly higher proportions of Mystiric Acid (MA), Palmitic Acid (PAM), Palmitoleic Acid (POA) and Stearoyl-CoA Desaturase (SCD)-16, compared to controls.

The results revealed that patients with severe involvements had high levels of POA and total MUFA associated with higher SCD-16 activity compared to those with minor ones. The receiver operator characteristic curve analysis revealed that POA could well discriminate BD patients with severe clinical manifestations. In the bivariate analysis, hsCRP was found to be positively correlated with total SAFA and POA elongase activity index but negatively correlated with SCD-18 activity index. The STA, POA, elongase and SCD-16 activity index are correlated with fibrinogen. On the other hand, the multivariate analysis showed that POA remained associated with higher levels of hsCRP.

Conclusion:

Unfavourable plasma SFA and MUFA profile were reported in BD patients. POA, which is associated with higher plasma hsCRP level, may play a role in the pathogenesis of BD.

Lung injury does not aggravate mechanical ventilation-induced early cerebral inflammation or apoptosis in an animal model

Introduction

The acute respiratory distress syndrome is not only associated with a high mortality, but also goes along with cognitive impairment in survivors. The cause for this cognitive impairment is still not clear. One possible mechanism could be cerebral inflammation as result of a “lung-brain-crosstalk”. Even mechanical ventilation itself can induce cerebral inflammation. We hypothesized, that an acute lung injury aggravates the cerebral inflammation induced by mechanical ventilation itself and leads to neuronal damage.

Methods

After approval of the institutional and state animal care committee 20 pigs were randomized to one of three groups: lung injury by central venous injection of oleic acid (n = 8), lung injury by bronchoalveolar lavage in combination with one hour of injurious ventilation (n = 8) or control (n = 6). Brain tissue of four native animals from a different study served as native group. For six hours all animals were ventilated with a tidal volume of 7 ml kg^-1 and a scheme for positive end-expiratory pressure and inspired oxygen fraction, which was adapted from the ARDS network tables. Afterwards the animals were killed and the brains were harvested for histological (number of neurons and microglia) and molecular biologic (TNFalpha, IL-1beta, and IL-6) examinations.

Results

There was no difference in the number of neurons or microglia cells between the groups. TNFalpha was significantly higher in all groups compared to native (p < 0.05), IL-6 was only increased in the lavage group compared to native (p < 0.05), IL-1beta showed no difference between the groups.

Discussion

With our data we can confirm earlier results, that mechanical ventilation itself seems to trigger cerebral inflammation. This is not aggravated by acute lung injury, at least not within the first 6 hours after onset. Nevertheless, it seems too early to dismiss the idea of lung-injury induced cerebral inflammation, as 6 hours might be just not enough time to see any profound effect.

Modulation of Haemophilus influenzae interaction with hydrophobic molecules by the VacJ/MlaA lipoprotein impacts strongly on its interplay with the airways

Airway infection by nontypeable Haemophilus influenzae (NTHi) associates to chronic obstructive pulmonary disease (COPD) exacerbation and asthma neutrophilic airway inflammation. Lipids are key inflammatory mediators in these disease conditions and consequently, NTHi may encounter free fatty acids during airway persistence. However, molecular information on the interplay NTHi-free fatty acids is limited, and we lack evidence on the importance of such interaction to infection. Maintenance of the outer membrane lipid asymmetry may play an essential role in NTHi barrier function and interaction with hydrophobic molecules. VacJ/MlaA-MlaBCDEF prevents phospholipid accumulation at the bacterial surface, being the only system involved in maintaining membrane asymmetry identified in NTHi. We assessed the relationship among the NTHi VacJ/MlaA outer membrane lipoprotein, bacterial and exogenous fatty acids, and respiratory infection. The vacJ/mlaA gene inactivation increased NTHi fatty acid and phospholipid global content and fatty acyl specific species, which in turn increased bacterial susceptibility to hydrophobic antimicrobials, decreased NTHi epithelial infection, and increased clearance during pulmonary infection in mice with both normal lung function and emphysema, maybe related to their shared lung fatty acid profiles. Altogether, we provide evidence for VacJ/MlaA as a key bacterial factor modulating NTHi survival at the human airway upon exposure to hydrophobic molecules.

Protective effects of grape seed and skin extract against high-fat-diet-induced lipotoxicity in rat lung

BACKGROUND

Obesity is a public health problem characterized by increased fat accumulation in different tissues. Obesity is directly linked to breathing problems and medical complications with lung, including obstructive sleep apnea syndrome, obesity hypoventilation syndrome, chronic obstructive pulmonary disease, asthma….In the present work, we aimed to investigate the effect of high fat diet (HFD) on lung lipotoxicity, oxidative stress, fatty acid composition and proportions in lung and implication in asthma development. The likely protection provided by grape seed extract (GSSE) was also investigated.

METHODS

In order to assess HFD effect on lung and GSSE protection we used a rat model. We analyzed the lipid plasma profile, lung peroxidation and antioxidant activities (SOD, CAT and POD). We also analyzed transition metals (Ca2+, Mg2+, Zn2+ and iron) and lung free fatty acids using gas chromatography coupled to mass spectrometry (GC-MS).

RESULTS

HFD induced lipid profile imbalance increasing cholesterol and VLDL-C. HFD also induced an oxidative stress assessed by elevated MDA level and the drop of antioxidant activities such as SOD, CAT and POD. Moreover, HFD induced mineral disturbances by decreasing magnesium level and increasing Calcium and iron levels. HFD induced also disturbances in lung fatty acid composition by increasing oleic, stearic and arachidonic acids. Interestingly, GSSE alleviated all these deleterious effects of HFD treatment.

CONCLUSION

As a whole, GSSE had a significant preventive effect against HFD-induced obesity, and hence may be used as an anti-obesity agent, and a benefic agent with potential applications against damages in lung tissue.

Ghrelin ameliorates acute lung injury induced by oleic acid via inhibition of endoplasmic reticulum stress

AIMS

Acute lung injury (ALI) is associated with excessive mortality and lacks appropriate therapy. Ghrelin is a novel peptide that protects the lung against ALI. This study aimed to investigate whether endoplasmic reticulum stress (ERS) mediates the protective effect of ghrelin on ALI.

MAIN METHODS

We used a rat oleic acid (OA)-induced ALI model. Pulmonary impairment was detected by hematoxylin and eosin (HE) staining, lung mechanics, wet/dry weight ratio, and arterial blood gas analysis. Plasma and lung content of ghrelin was examined by ELISA, and mRNA expression was measured by quantitative real-time PCR. Protein levels were detected by western blot.

KEY FINDINGS

Rats with OA treatment showed significant pulmonary injury, edema, inflammatory cellular infiltration, cytokine release, hypoxia and CO₂ retention as compared with controls. Plasma and pulmonary content of ghrelin was reduced in rats with ALI, and mRNA expression was downregulated. Ghrelin (10nmol/kg) treatment ameliorated the above symptoms, but treatment with the ghrelin antagonists D-Lys³ GHRP-6 (1μmol/kg) and JMV 2959 (6mg/kg) exacerbated the symptoms. ERS induced by OA was prevented by ghrelin and augmented by ghrelin antagonist treatment. The ERS inducer, tunicamycin (Tm) prevented the ameliorative effect of ghrelin on ALI. The decreased ratio of p-Akt and Akt induced by OA was improved by ghrelin treatment, and was further exacerbated by ghrelin antagonists.

SIGNIFICANCE

Ghrelin protects against ALI by inhibiting ERS. These results provide a new target for prevention and therapy of ALI.

Na/K Pump and Beyond: Na/K-ATPase as a Modulator of Apoptosis and Autophagy

Lung cancer is a leading cause of global cancer deaths. Na/K-ATPase has been studied as a target for cancer treatment. Cardiotonic steroids (CS) trigger intracellular signalling upon binding to Na/K-ATPase. Normal lung and tumour cells frequently express different pump isoforms. Thus, Na/K-ATPase is a powerful target for lung cancer treatment. Drugs targeting Na/K-ATPase may induce apoptosis and autophagy in transformed cells. We argue that Na/K-ATPase has a role as a potential target in chemotherapy in lung cancer treatment. We discuss the effects of Na/K-ATPase ligands and molecular pathways inducing deleterious effects on lung cancer cells, especially those leading to apoptosis and autophagy.

WITHDRAWN: Decreased level of endogenous ghrelin is involved in the progression of lung injury induced by oleic acid

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Metabolic pathways of lung inflammation revealed by high-resolution metabolomics (HRM) of H1N1 influenza virus infection in mice

Influenza is a significant health concern worldwide. Viral infection induces local and systemic activation of the immune system causing attendant changes in metabolism. High-resolution metabolomics (HRM) uses advanced mass spectrometry and computational methods to measure thousands of metabolites inclusive of most metabolic pathways. We used HRM to identify metabolic pathways and clusters of association related to inflammatory cytokines in lungs of mice with H1N1 influenza virus infection. Infected mice showed progressive weight loss, decreased lung function, and severe lung inflammation with elevated cytokines [interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ] and increased oxidative stress via cysteine oxidation. HRM showed prominent effects of influenza virus infection on tryptophan and other amino acids, and widespread effects on pathways including purines, pyrimidines, fatty acids, and glycerophospholipids. A metabolome-wide association study (MWAS) of the aforementioned inflammatory cytokines was used to determine the relationship of metabolic responses to inflammation during infection. This cytokine-MWAS (cMWAS) showed that metabolic associations consisted of distinct and shared clusters of 396 metabolites highly correlated with inflammatory cytokines. Strong negative associations of selected glycosphingolipid, linoleate, and tryptophan metabolites with IFN-γ contrasted strong positive associations of glycosphingolipid and bile acid metabolites with IL-1β, TNF-α, and IL-10. Anti-inflammatory cytokine IL-10 had strong positive associations with vitamin D, purine, and vitamin E metabolism. The detailed metabolic interactions with cytokines indicate that targeted metabolic interventions may be useful during life-threatening crises related to severe acute infection and inflammation.