Antioxidant micronutrients for lung disease in cystic fibrosis

The effect of fluoroquinolones and antioxidans on biofilm formation by Proteus mirabilis strains

Background

Fluoroquinolones are a group of antibiotics used in urinary tract infections. Unfortunately, resistance to this group of drugs is currently growing. The combined action of fluoroquinolones and other antibacterial and anti-biofilm substances may extend the use of this therapeutic option by clinicians. The aim of the study was to determine the effect of selected fluoroquinolones and therapeutic concentrations of ascorbic acid and rutoside on biofilm formation by Proteus mirabilis.

Materials and methods

The study included 15 strains of P. mirabilis isolated from urinary tract infections in patients of the University Hospital No. 1 dr A. Jurasz in Bydgoszcz (Poland). The metabolic activity of the biofilm treated with 0.4 mg/ml ascorbic acid, 0.02 µg/ml rutoside and chemotherapeutic agents (ciprofloxacin, norfloxacin) in the concentration range of 0.125–4.0 MIC (minimum inhibitory concentration) was assessed spectrophotometrically.

Results

Both ciprofloxacin and norfloxacin inhibited biofilm formation by the tested strains. The biofilm reduction rate was correlated with the increasing concentration of antibiotic used. No synergism in fluoroquinolones with ascorbic acid, rutoside or both was found. The ascorbic acid and rutoside combination, however, significantly decreased biofilm production.

Conclusions

Our research proves a beneficial impact of ascorbic acid with rutoside supplementation on biofilm of P. mirabilis strains causing urinary tract infections.

15LO1 dictates glutathione redox changes in asthmatic airway epithelium to worsen type-2 inflammation

Altered redox biology challenges all cells, with compensatory responses often determining a cell’s fate. When 15 lipoxygenase 1 (15LO1), a lipid-peroxidizing enzyme abundant in asthmatic human airway epithelial cells (HAECs), binds phosphatidylethanolamine-binding protein 1 (PEBP1), hydroperoxy-phospholipids, which drive ferroptotic cell death, are generated. Peroxidases, including glutathione peroxidase 4 (GPX4), metabolize hydroperoxy-phospholipids to hydroxy derivatives to prevent ferroptotic death, but consume reduced glutathione (GSH). The cystine transporter SLC7A11 critically restores/maintains intracellular GSH. We hypothesized that high 15LO1, PEBP1, and GPX4 activity drives abnormal asthmatic redox biology, evidenced by lower bronchoalveolar lavage (BAL) fluid and intraepithelial cell GSH:oxidized GSH (GSSG) ratios, to enhance type 2 (T2) inflammatory responses. GSH, GSSG (enzymatic assays), 15LO1, GPX4, SLC7A11, and T2 biomarkers (Western blot and RNA-Seq) were measured in asthmatic and healthy control (HC) cells and fluids, with siRNA knockdown as appropriate. GSSG was higher and GSH:GSSG lower in asthmatic compared with HC BAL fluid, while intracellular GSH was lower in asthma. In vitro, a T2 cytokine (IL-13) induced 15LO1 generation of hydroperoxy-phospholipids, which lowered intracellular GSH and increased extracellular GSSG. Lowering GSH further by inhibiting SLC7A11 enhanced T2 inflammatory protein expression and ferroptosis. Ex vivo, redox imbalances corresponded to 15LO1 and SLC7A11 expression, T2 biomarkers, and worsened clinical outcomes. Thus, 15LO1 pathway–induced redox biology perturbations worsen T2 inflammation and asthma control, supporting 15LO1 as a therapeutic target.

Eszett (ẞ; ß)-carotene is an erroneous, non-existent false positive of beta (β)-carotene

There are several isomers of carotene, the main ones being alpha and beta carotene (i.e., α-carotene and β-carotene). The latter serves as a precursor for vitamin A, and is thus a well-studied carotenoid in health, food, and nutrition research. A German special character, the Eszett (uppercase or capital ẞ; lowercase ß), has been confused with the Greek, lowercase beta (β) in some papers in the biomedical literature, and when the lowercase Eszett is written in italics, it looks even more similar to the Greek letter beta. Curiously, this linguistic error has given rise to a "new" form of carotene, Eszett (ß)-carotene, which does not exist. A search on PubMed, Elsevier's sciencedirect.com, and Springer Nature's SpringerLink platforms reveals that there are potentially dozens, if not hundreds of cases or more of this false-positive carotene "isomer," which was supposed to represent β-carotene, but has, through a typographic error, represented a "new" and non-existent form of carotene, ß-carotene. This clearly represents erroneous literature that needs correction.

Reactive Oxygen Species: Drivers of Physiological and Pathological Processes

Since the Great Oxidation Event, about 2.4 billion years ago, the Earth is immersed in an oxidizing atmosphere. Thus, it has been proposed that excess oxygen, originally a waste product of photosynthetic cyanobacteria, induced oxidative stress and the production of reactive oxygen species (ROS), which have since acted as fundamental drivers of biologic evolution and eukaryogenesis. Indeed, throughout an organism’s lifespan, ROS affect directly (as mutagens) or indirectly (as messengers and regulators) all structural and functional components of cells, and many aspects of cell biology. Whether left unchecked by protective antioxidant systems, excess ROS not only cause genomic mutations but also induce irreversible oxidative modification of proteins (protein oxidation and peroxidation), lipids and glycans (advanced lipoxidation and glycation end products), impairing their function and promoting disease or cell death. Conversely, low-level local ROS play an important role both as redox-signaling molecules in a wide spectrum of pathways involved in the maintenance of cellular homeostasis (MAPK/ERK, PTK/PTP, PI3K-AKT-mTOR), and regulating key transcription factors (NFκB/IκB, Nrf2/KEAP1, AP-1, p53, HIF-1). Consequently, ROS can shape a variety of cellular functions, including proliferation, differentiation, migration and apoptosis. In this review, we will give a brief overview of the relevance of ROS in both physiological and pathological processes, particularly inflammation and aging. In-depth knowledge of the molecular mechanisms of ROS actuation and their influence under steady-state and stressful conditions will pave the way for the development of novel therapeutic interventions. This will mitigate the harmful outcomes of ROS in the onset and progression of a variety of chronic inflammatory and age-related diseases.

Novel Anti-Inflammatory Approaches for Cystic Fibrosis Lung Disease: Identification of Molecular Targets and Design of Innovative Therapies

Cystic fibrosis (CF) is the most common genetic disorder among Caucasians, estimated to affect more than 70,000 people in the world. Severe and persistent bronchial inflammation and chronic bacterial infection, along with airway mucus obstruction, are hallmarks of CF lung disease and participate in its progression. Anti-inflammatory therapies are, therefore, of particular interest for CF lung disease. Furthermore, a better understanding of the molecular mechanisms involved in airway infection and inflammation in CF has led to the development of new therapeutic approaches that are currently under evaluation by clinical trials. These new strategies dedicated to CF inflammation are designed to treat different dysregulated aspects such as oxidative stress, cytokine secretion, and the targeting of dysregulated pathways. In this review, we summarize the current understanding of the cellular and molecular mechanisms that contribute to abnormal lung inflammation in CF, as well as the new anti-inflammatory strategies proposed to CF patients by exploring novel molecular targets and novel drug approaches.

Antioxidant supplementation for lung disease in cystic fibrosis

BACKGROUND

Airway infection leads to progressive damage of the lungs in cystic fibrosis (CF) and oxidative stress has been implicated in the etiology. Supplementation of antioxidant micronutrients (vitamin E, vitamin C, beta-carotene and selenium) or N-acetylcysteine (NAC) as a source of glutathione, may therefore potentially help maintain an oxidant-antioxidant balance. Glutathione or NAC can also be inhaled and if administered in this way can also have a mucolytic effect besides the antioxidant effect. Current literature suggests a relationship between oxidative status and lung function. This is an update of a previously published review.

OBJECTIVES

To synthesise existing knowledge on the effect of antioxidants such as vitamin C, vitamin E, beta-carotene, selenium and glutathione (or NAC as precursor of glutathione) on lung function through inflammatory and oxidative stress markers in people with CF.

SEARCH METHODS

The Cochrane Cystic Fibrosis and Genetic Disorders Group's Cystic Fibrosis Trials Register and PubMed were searched using detailed search strategies. We contacted authors of included studies and checked reference lists of these studies for additional, potentially relevant studies. We also searched online trials registries.Last search of Cystic Fibrosis Trials Register: 08 January 2019.

SELECTION CRITERIA

Randomised and quasi-randomised controlled studies comparing antioxidants as listed above (individually or in combination) in more than a single administration to placebo or standard care in people with CF.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, extracted data and assessed the risk of bias in the included studies. We contacted study investigators to obtain missing information. If meta-analysed, studies were subgrouped according to supplement, method of administration and the duration of supplementation. We assessed the quality of the evidence using GRADE.

MAIN RESULTS

One quasi-randomised and 19 randomised controlled studies (924 children and adults) were included; 16 studies (n = 639) analysed oral antioxidant supplementation and four analysed inhaled supplements (n = 285). Only one of the 20 included studies was judged to be free of bias.Oral supplements versus controlThe change from baseline in forced expiratory volume in one second (FEV₁) % predicted at three months and six months was only reported for the comparison of NAC to control. Four studies (125 participants) reported at three months; we are uncertain whether NAC improved FEV₁ % predicted as the quality of the evidence was very low, mean difference (MD) 2.83% (95% confidence interval (CI) -2.16 to 7.83). However, at six months two studies (109 participants) showed that NAC probably increased FEV₁ % predicted from baseline (moderate-quality evidence), MD 4.38% (95% CI 0.89 to 7.87). A study of a combined vitamin and selenium supplement (46 participants) reported a greater change from baseline in FEV₁ % predicted in the control group at two months, MD -4.30% (95% CI -5.64 to -2.96). One study (61 participants) found that NAC probably makes little or no difference in the change from baseline in quality of life (QoL) at six months (moderate-quality evidence), standardised mean difference (SMD) -0.03 (95% CI -0.53 to 0.47), but the two-month combined vitamin and selenium study reported a small difference in QoL in favour of the control group, SMD -0.66 (95% CI -1.26 to -0.07). The NAC study reported on the change from baseline in body mass index (BMI) (62 participants) and similarly found that NAC probably made no difference between groups (moderate-quality evidence). One study (69 participants) found that a mixed vitamin and mineral supplement may lead to a slightly lower risk of pulmonary exacerbation at six months than a multivitamin supplement (low-quality evidence). Nine studies (366 participants) provided information on adverse events, but did not find any clear and consistent evidence of differences between treatment or control groups with the quality of the evidence ranging from low to moderate. Studies of β-carotene and vitamin E consistently reported greater plasma levels of the respective antioxidants.Inhaled supplements versus controlTwo studies (258 participants) showed inhaled glutathione probably improves FEV₁ % predicted at three months, MD 3.50% (95% CI 1.38 to 5.62), but not at six months compared to placebo, MD 2.30% (95% CI -0.12 to 4.71) (moderate-quality evidence). The same studies additionally reported an improvement in FEV₁ L in the treated group compared to placebo at both three and six months. One study (153 participants) reported inhaled glutathione probably made little or no difference to the change in QoL from baseline, MD 0.80 (95% CI -1.63 to 3.23) (moderate-quality evidence). No study reported on the change from baseline in BMI at six months, but one study (16 participants) reported at two months and a further study (105 participants) at 12 months; neither study found any difference at either time point. One study (153 participants) reported no difference in the time to the first pulmonary exacerbation at six months. Two studies (223 participants) reported treatment may make little or no difference in adverse events (low-quality evidence), a further study (153 participants) reported that the number of serious adverse events were similar across groups.

AUTHORS' CONCLUSIONS

With regards to micronutrients, there does not appear to be a positive treatment effect of antioxidant micronutrients on clinical end-points; however, oral supplementation with glutathione showed some benefit to lung function and nutritional status. Based on the available evidence, inhaled and oral glutathione appear to improve lung function, while oral administration decreases oxidative stress; however, due to the very intensive antibiotic treatment and other concurrent treatments that people with CF take, the beneficial effect of antioxidants remains difficult to assess in those with chronic infection without a very large population sample and a long-term study period. Further studies, especially in very young children, using outcome measures such as lung clearance index and the bronchiectasis scores derived from chest scans, with improved focus on study design variables (such as dose levels and timing), and elucidating clear biological pathways by which oxidative stress is involved in CF, are necessary before a firm conclusion regarding effects of antioxidants supplementation can be drawn. The benefit of antioxidants in people with CF who receive CFTR modulators therapies should also be assessed in the future.

Protective Effect of Polyunsaturated Fatty Acids against Experimental Lung Injury Induced by Acute Ethanol Inhalation

Ethanol-induced diseases include oxidative mechanisms by which prolonged endoplasmic reticulum (ER) stress results in genesis and accumulation of cytotoxic total fatty acid ethyl esters (FAEEs, non-oxidative metabolites of ethanol). FAEEs participate in the pathogenesis of alcoholic lung disease. Polyunsaturated fatty acids (PUFA) offer a possible protective effect against damage induced by ethanol inhalation. The present study aimed to investigate the protective effect of flaxseed and fish oils administration against toxicity induced by ethanol inhalation. Forty healthy female albino rats were divided into four groups (control, ethanol, flaxseed and fish oils). Lung superoxide dismutase (SOD) and malondialdehyde (MDA) were measured. Plasma advanced oxidation end product (AOPP) and phosphatidylinositol 3- kinase (PI3K) were determined. Erythrocyte membrane fatty acids were extracted and fractionated by HPLC. Ethanol inhalation results in significant increase in lung MDA, plasma AOPP and erythrocyte membrane arachidonic acid (AA), linolenic acid (LA), and oleic acid (OA) along with a significant decrease in erythrocyte membrane alpha-linolenic acid (ALA), lung SOD, and plasma PI3K while pretreatment with flaxseed and fish oils daily (1.2 ml/kg) significantly attenuated these parameters. Supplementation of marine PUFAs reduced the oxidative stress induced by ethanol inhalation in experimental animals.

Reactive Oxygen Species, Biomarkers of Microvascular Maturation and Alveolarization, and Antioxidants in Oxidative Lung Injury

The lungs of extremely low gestational age neonates (ELGANs) are deficient in pulmonary surfactant and are incapable of efficient gas exchange necessary for successful transition from a hypoxic intrauterine environment to ambient air. To improve gas exchange and survival, ELGANs often receive supplemental oxygen with mechanical ventilation which disrupts normal lung developmental processes, including microvascular maturation and alveolarization. Factors that regulate these developmental processes include vascular endothelial growth factor and matrix metalloproteinases, both of which are influenced by generation of oxygen byproducts, or reactive oxygen species (ROS). ELGANs are also deficient in antioxidants necessary to scavenge excessive ROS. Thus, the accumulation of ROS in the preterm lungs exposed to prolonged hyperoxia, results in inflammation and development of bronchopulmonary dysplasia (BPD), a form of chronic lung disease (CLD). Despite advances in neonatal care, BPD/CLD remains a major cause of neonatal morbidity and mortality. The underlying mechanisms are not completely understood, and the benefits of current therapeutic interventions are limited. The association between ROS and biomarkers of microvascular maturation and alveolarization, as well as antioxidant therapies in the setting of hyperoxia-induced neonatal lung injury are reviewed in this article.

Oxidative Stress and Therapeutic Development in Lung Diseases

Oxidative stress has many implications in the pathogenesis of lung diseases. In this review, we provide an overview of Reactive Oxygen Species (ROS) and nitrogen (RNS) species and antioxidants, how they relate to normal physiological function and the pathophysiology of different lung diseases, and therapeutic strategies. The production of ROS/RNS from endogenous and exogenous sources is first discussed, followed by antioxidant systems that restore oxidative balance and cellular homeostasis. The contribution of oxidant/antioxidant imbalance in lung disease pathogenesis is also discussed. An overview of therapeutic strategies is provided, such as augmenting NO bioactivity, blocking the production of ROS/RNS and replacement of deficient antioxidants. The limitations of current strategies and failures of clinical trials are then addressed, followed by discussion of novel experimental approaches for the development of improved antioxidant therapies.

Vitamin A supplementation for cystic fibrosis

BACKGROUND

People with cystic fibrosis and pancreatic insufficiency are at risk of fat soluble vitamin deficiency as these vitamins (A, D, E and K) are co-absorbed with fat. Thus, some cystic fibrosis centres routinely administer these vitamins as supplements but the centres vary in their approach of addressing the possible development of deficiencies in these vitamins. Vitamin A deficiency causes predominantly eye and skin problems while supplementation of vitamin A to excessive levels may cause harm to the respiratory and skeletal systems in children. Thus a systematic review on vitamin A supplementation in people with cystic fibrosis would help guide clinical practice.

OBJECTIVES

To determine if vitamin A supplementation in children and adults with cystic fibrosis:1. reduces the frequency of vitamin A deficiency disorders;2. improves general and respiratory health;3. increases the frequency of vitamin A toxicity.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search of the Group's Cystic Fibrosis Trials Register: 07 April 2014.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing all preparations of oral vitamin A used as a supplement compared to either no supplementation (or placebo) at any dose and for any duration, in children or adults with cystic fibrosis (defined by sweat tests or genetic testing) with and without pancreatic insufficiency.

DATA COLLECTION AND ANALYSIS

No relevant studies for inclusion were identified in the search.

MAIN RESULTS

No studies were included in this review.

AUTHORS' CONCLUSIONS

As there were no randomised or quasi-randomised controlled trials identified, we cannot draw any conclusions on the benefits (or otherwise) of regular administration of vitamin A in people with cystic fibrosis. Until further data are available, country or region specific guidelines on the use of vitamin A in people with cystic fibrosis should be followed.

Mitochondria and reactive oxygen species: physiology and pathophysiology

The air that we breathe contains nearly 21% oxygen, most of which is utilized by mitochondria during respiration. While we cannot live without it, it was perceived as a bane to aerobic organisms due to the generation of reactive oxygen and nitrogen metabolites by mitochondria and other cellular compartments. However, this dogma was challenged when these species were demonstrated to modulate cellular responses through altering signaling pathways. In fact, since this discovery of a dichotomous role of reactive species in immune function and signal transduction, research in this field grew at an exponential pace and the pursuit for mechanisms involved began. Due to a significant number of review articles present on the reactive species mediated cell death, we have focused on emerging novel pathways such as autophagy, signaling and maintenance of the mitochondrial network. Despite its role in several processes, increased reactive species generation has been associated with the origin and pathogenesis of a plethora of diseases. While it is tempting to speculate that anti-oxidant therapy would protect against these disorders, growing evidence suggests that this may not be true. This further supports our belief that these reactive species play a fundamental role in maintenance of cellular and tissue homeostasis.

Progress in cystic fibrosis and the CF Therapeutics Development Network

Cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians, affects approximately 70 000 individuals worldwide. In 1998, the Cystic Fibrosis Foundation (CFF) launched the CF Therapeutics Development Network (CF-TDN) as a central element of its Therapeutics Development Programme. Designed to accelerate the clinical evaluation of new therapies needed to fulfil the CFF mission to control and cure CF, the CF-TDN has conducted 75 clinical trials since its inception, and has contributed to studies as varied as initial safety and proof of concept trials to pivotal programmes required for regulatory approval. This review highlights recent and significant research efforts of the CF-TDN, including a summary of contributions to studies involving CF transmembrane conductance regulator (CFTR) modulators, airway surface liquid hydrators and mucus modifiers, anti-infectives, anti-inflammatories, and nutritional therapies. Efforts to advance CF biomarkers, necessary to accelerate the therapeutic goals of the network, are also summarised.

Vitamin A supplementation for cystic fibrosis

BACKGROUND

People with cystic fibrosis and pancreatic insufficiency are at risk of fat soluble vitamin deficiency as these vitamins (A, D, E and K) are co-absorbed with fat. Thus, some cystic fibrosis centres routinely administer these vitamins as supplements but the centres vary in their approach of addressing the possible development of deficiencies in these vitamins. Vitamin A deficiency causes predominantly eye and skin problems while supplementation of vitamin A to excessive levels may cause harm to the respiratory and skeletal systems in children. Thus a systematic review on vitamin A supplementation in people with cystic fibrosis would help guide clinical practice.

OBJECTIVES

To determine if vitamin A supplementation in children and adults with CF: 1. reduces the frequency of vitamin A deficiency disorders; 2. improves general and respiratory health; 3. increases the frequency of vitamin A toxicity.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search of the Group's Cystic Fibrosis Trials Register: 23 May 2012.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing all preparations of oral vitamin A used as a supplement compared to either no supplementation (or placebo) at any dose and for any duration, in children or adults with cystic fibrosis (defined by sweat tests or genetic testing) with and without pancreatic insufficiency.

DATA COLLECTION AND ANALYSIS

No relevant studies for inclusion were identified in the search.

MAIN RESULTS

No studies were included in this review.

AUTHORS' CONCLUSIONS

As there were no randomised or quasi-randomised controlled trials identified, we cannot draw any conclusions on the benefits (or otherwise) of regular administration of vitamin A in people with cystic fibrosis. Until further data are available, country or region specific guidelines on the use of vitamin A in people with cystic fibrosis should be followed.

Glutathione redox control of asthma: from molecular mechanisms to therapeutic opportunities

Asthma is a chronic inflammatory disorder of the airways associated with airway hyper-responsiveness and airflow limitation in response to specific triggers. Whereas inflammation is important for tissue regeneration and wound healing, the profound and sustained inflammatory response associated with asthma may result in airway remodeling that involves smooth muscle hypertrophy, epithelial goblet-cell hyperplasia, and permanent deposition of airway extracellular matrix proteins. Although the specific mechanisms responsible for asthma are still being unraveled, free radicals such as reactive oxygen species and reactive nitrogen species are important mediators of airway tissue damage that are increased in subjects with asthma. There is also a growing body of literature implicating disturbances in oxidation/reduction (redox) reactions and impaired antioxidant defenses as a risk factor for asthma development and asthma severity. Ultimately, these redox-related perturbations result in a vicious cycle of airway inflammation and injury that is not always amenable to current asthma therapy, particularly in cases of severe asthma. This review will discuss disruptions of redox signaling and control in asthma with a focus on the thiol, glutathione, and reduced (thiol) form (GSH). First, GSH synthesis, GSH distribution, and GSH function and homeostasis are discussed. We then review the literature related to GSH redox balance in health and asthma, with an emphasis on human studies. Finally, therapeutic opportunities to restore the GSH redox balance in subjects with asthma are discussed.

The role of selenium in inflammation and immunity: from molecular mechanisms to therapeutic opportunities

Dietary selenium (]Se), mainly through its incorporation into selenoproteins, plays an important role in inflammation and immunity. Adequate levels of Se are important for initiating immunity, but they are also involved in regulating excessive immune responses and chronic inflammation. Evidence has emerged regarding roles for individual selenoproteins in regulating inflammation and immunity, and this has provided important insight into mechanisms by which Se influences these processes. Se deficiency has long been recognized to negatively impact immune cells during activation, differentiation, and proliferation. This is related to increased oxidative stress, but additional functions such as protein folding and calcium flux may also be impaired in immune cells under Se deficient conditions. Supplementing diets with above-adequate levels of Se can also impinge on immune cell function, with some types of inflammation and immunity particularly affected and sexually dimorphic effects of Se levels in some cases. In this comprehensive article, the roles of Se and individual selenoproteins in regulating immune cell signaling and function are discussed. Particular emphasis is given to how Se and selenoproteins are linked to redox signaling, oxidative burst, calcium flux, and the subsequent effector functions of immune cells. Data obtained from cell culture and animal models are reviewed and compared with those involving human physiology and pathophysiology, including the effects of Se levels on inflammatory or immune-related diseases including anti-viral immunity, autoimmunity, sepsis, allergic asthma, and chronic inflammatory disorders. Finally, the benefits and potential adverse effects of intervention with Se supplementation for various inflammatory or immune disorders are discussed.