Objectives High-dose vitamin D3increases plasma total 25-hydroxyvitamin D [25(OH)D] in critically ill, ventilated patients; however, to our knowledge, the effect on plasma levels of free (nonprotein-bound) 25(OH)D has not been investigated in critical illness. Moreover, the relationship of free 25(OH)D and the regulation of endogenous antimicrobial peptides (AMPs) remains unknown. The aims of this study were to determine in critically ill adults with respiratory failure the effect of previous high-dose regimens of vitamin D3on free 25(OH)D concentrations, the relationship of free 25(OH)D with circulating cathelicidin (LL-37) and human beta-defensin-2 (hBD-2), and the associations between plasma levels of free 25(OH)D and these AMPs to alveolar macrophage phagocytosis function. Methods In a double blind, randomized controlled trial, critically ill ventilator-dependent adults (N = 30) received enteral vitamin D3(250,000 or 500,000 IU total over 5 d) or placebo. Plasma was obtained serially for concentrations of free 25(OH)D, LL-37, hBD-2, and expression of peripheral blood mononuclear cell human cationic antimicrobial protein (hCAP18) mRNA. Total 25(OH)D and LL-37 concentrations and alveolar macrophage phagocytosis were determined in bronchoalveolar lavage fluid. Results Plasma concentrations of free 25(OH)D over time were correlated with total 25(OH)D levels (r= 0.82; P < 0.001). The increase in free 25(OH)D was greater with the 500 000 IU vitamin D3dose than with the lower dose. The percent change in mRNA expression of hCAP18 was positively associated with percent change in free 25(OH)D at days 7 and 14 (ρ = 0.48; P = 0.04 and ρ = 0.59; P = 0.03, respectively). Additionally, plasma LL-37 levels correlated with the percentage of alveolar macrophages exhibiting phagocytosis (ρ = 0.51; P = 0.04). Conclusions The present study found a dose-related increase in plasma free-25(OH)D levels, which was associated with increasing circulating mRNA expression of hCAP18 over time. There were no correlations between changes in total and free 25(OH)D against plasma LL-37 and hBD-2 concentrations. Larger studies appear warranted to determine the impact of high-dose vitamin D3administration on endogenous AMPs.
Objective
Lung infections are a leading cause of death in HIV-infected individuals. Measuring redox in HIV-infected individuals may identify those with chronic oxidative stress who are at increased risk for lung infection. We sought to estimate the association between HIV infection and oxidative stress in the lung, as reflected by decreased levels of glutathione and cysteine in the epithelial lining fluid.
Methods
Bronchoalveolar lavage (BAL) fluid was collected from healthy HIV-infected subjects and controls. Individuals were excluded if they had evidence of major medical co-morbidities, were malnourished or smoked cigarettes.
Results
We enrolled 22 otherwise healthy HIV and 21 non-HIV subjects. Among the HIV-infected subjects, 72.7% were on anti-retroviral therapy (ART) with a median CD4 count of 438 (279.8–599) and viral load of 0 (0–1.0) log copies/mL. There were no significant differences in median BAL fluid glutathione and cysteine levels between HIV and HIV-uninfected subjects. However, BAL glutathione was significantly higher in HIV-infected subjects on anti-retroviral therapy (ART) compared to those not on ART [367.4 (102–965.3) nM vs. 30.8 (1.0–112.1) nM, p = 0.008]. Further, HIV infection with ART was associated with an OR of 2.02 for increased BAL glutathione when adjusted for age and body mass index, whereas HIV infection without ART was associated with an OR of 2.17 for decreased BAL glutathione.
Conclusion
HIV infection without ART was associated with increased oxidative stress, as reflected by decreased alveolar glutathione levels, in otherwise healthy HIV-infected individuals. Further study needs to be done identify predictors of lung health in HIV and to address the role of ART in improving lung immunity.
Background:The health implications of in utero alcohol exposure have been difficult to study in very-low-birth-weight newborns (VLBW) because of an inability to identify maternal alcohol exposure. Fatty acid ethyl esters (FAEEs) are elevated in meconium of alcohol-exposed term newborns. We hypothesized that meconium FAEEs would be similarly elevated in alcohol-exposed VLBW premature newborns.
Methods:In a retrospective cohort study of 64 VLBW neonates, newborns were classified into Non-Exposed, Any Exposure, or Weekly Exposure groups based on an in-depth structured maternal interview. Meconium FAEE concentrations were quantified via gas chromatography mass spectrometry.
Results:Alcohol exposure during Trimester 1 (Any Exposure) occurred in ∼30% of the pregnancies, while 11% of the subjects reported drinking ≥ 1 drink/week (Weekly Exposure). Meconium ethyl linolenate was higher in Any Exposure (P = 0.01) and Weekly Exposure groups (P = 0.005) compared to the Non-Exposed VLBW group. There was a significant positive correlation between Trimester 1 drinking amounts and the concentration of meconium ethyl linolenate (P = 0.005). Adjusted receiver operating characteristic (ROC) curves evaluating ethyl linolenate to identify alcohol-exposed VLBW newborns generated areas under the curve of 88% with sensitivities of 86-89% and specificities of 83-88%.
Conclusion:Despite prematurity, meconium FAEEs hold promise to identify the alcohol-exposed VLBW newborn.
Background:
Proteolytic degradation of epithelial sodium channels (ENaC) assists in regulating net salt and water balance in lung epithelia.
Results:
H2O2 increases surface expression of α-ENaC, transepithelial Na transport, and alveolar fluid clearance via redox-sensitive Nedd8.
Conclusion:
Redox-sensitive Nedd8 is involved in the ubiquitination of lung ENaC.
Significance:
Understanding ROS-mediated signaling of lung ENaC is crucial for understanding pulmonary physiology and pathology.
Background
Human immunodeficiency virus type 1 (HIV-1) infection and the consequent acquired immunodeficiency syndrome (AIDS) has protean manifestations, including muscle wasting and cardiomyopathy, which contribute to its high morbidity. The pathogenesis of these myopathies remains partially understood, and may include nutritional deficiencies, biochemical abnormalities, inflammation, and other mechanisms due to viral infection and replication. Growing evidence has suggested that HIV-1-related proteins expressed by the host in response to viral infection, including Tat and gp120, may also be involved in the pathophysiology of AIDS, particularly in cells or tissues that are not directly infected with HIV-1. To explore the potentially independent effects of HIV-1-related proteins on heart and skeletal muscles, we used a transgenic rat model that expresses several HIV-1-related proteins (e.g., Tat, gp120, and Nef). Outcome measures included basic heart and skeletal muscle morphology, glutathione metabolism and oxidative stress, and gene expressions of atrogin-1, muscle ring finger protein-1 (MuRF-1) and Transforming Growth Factor-β1 (TGFβ1), three factors associated with muscle catabolism.
Results
Consistent with HIV-1 associated myopathies in humans, HIV-1 transgenic rats had increased relative heart masses, decreased relative masses of soleus, plantaris and gastrocnemius muscles, and decreased total and myosin heavy chain type-specific plantaris muscle fiber areas. In both tissues, the levels of cystine (Cyss), the oxidized form of the anti-oxidant cysteine (Cys), and Cyss:Cys ratios were significantly elevated, and cardiac tissue from HIV-1 transgenic rats had altered glutathione metabolism, all reflective of significant oxidative stress. In HIV-1 transgenic rat hearts, MuRF-1 gene expression was increased. Further, HIV-1-related protein expression also increased atrogin-1 (~14- and ~3-fold) and TGFβ1 (~5-fold and ~3-fold) in heart and plantaris muscle tissues, respectively.
Conclusion
We provide compelling experimental evidence that HIV-1-related proteins can lead to significant cardiac and skeletal muscle complications independently of viral infection or replication. Our data support the concept that HIV-1-related proteins are not merely disease markers, but rather have significant biological activity that may lead to increased oxidative stress, the stimulation of redox-sensitive pathways, and altered muscle morphologies. If correct, this pathophysiological scheme suggests that the use of dietary thiol supplements could reduce skeletal and cardiac muscle dysfunction in HIV-1-infected individuals.
Alcoholic patients have an increased risk of respiratory infections, which is partially due to an impaired immune response of alveolar macrophages. The mechanisms by which alcohol impairs alveolar macrophage function are poorly understood. In this study, we demonstrated in a guinea pig model that chronic ethanol ingestion significantly impaired alveolar macrophage differentiation and function. Isolated alveolar macrophages were separated into 4 different subpopulations with varying densities and levels of maturation. Compared to control values, chronic ethanol ingestion decreased the percentage of alveolar macrophages in the mature fractions by ~60%. Alveolar macrophage function in each subpopulation was determined by measuring phagocytosis of FITC-labeled S. aureus. Alveolar macrophages from ethanol-fed animals had ~80% decrease in the phagocytic index. Western blot and immunohistochemical analysis of the differential markers GM-CSF receptor α (GM-CSFR-α), PU.1, CD11c, and CD11b verified that alcoholic macrophages displayed impaired terminal differentiation. While oral supplementation with the glutathione precursor S-adenosyl-methionine (SAM) did not alter the maturational status of control animals, SAM s supplementation shifted the distribution of macrophages to more mature fractions, normalized the phagocytic index; as well as normalized expression of CD11c, CD11b, PU.1, and GM-CSFR-α. Chronic ethanol ingestion also impaired the differentiation status of interstitial macrophages which was normalized by SAM supplementation. This improvement in the maturational status suggested that ethanol-induced oxidant stress is a central feature in impaired terminal differentiation of macrophages in the interstitial and alveolar space. Therefore, strategies targeting pulmonary oxidant stress may restore macrophage differentiation and function even after chronic ethanol ingestion.
Acute lung injury affects close to 200,000 people in the U.S. annually and leads to death in 40–50% of affected patients. Chronic ethanol abuse is thought to contribute to up to 40–50% of subjects who develop acute lung injury. We previously demonstrated in a rat model that chronic ethanol ingestion promoted acute lung injury and associated with chronic oxidant stress, activated matrix metalloproteinases, increased release of transforming growth factor-β, as well as increased expression and deposition of fibronectin, a matrix glycoprotein implicated in lung injury and repair. Since fibronectin can activate monocytes to increase proinflammatory cytokine expression, we hypothesized that generation of fibronectin-enriched matrices during chronic ethanol ingestion might contribute to the development of acute lung injury by stimulating unopposed inflammation. To test this hypothesis, we harvested alveolar type II cells from rats fed the Lieber DiCarli diet (6 wk; 36% of calories from ethanol). After 96 hours of culture, the matrices deposited ex vivo by the type II cells derived from ethanol-fed rats showed increased amounts of fibronectin protein as demonstrated by ELISA. When monocytic U937 cells were plated atop these matrices, there was increased expression of interleukin-1β. This stimulation was inhibited by antibodies against α5β1, a receptor that mediates many of the biological effects of fibronectin. We then tested whether antioxidants ameliorated these effects. Dietary supplements of the antioxidants N-acetylcysteine and Procysteine normalized matrix production by type II cells. Furthermore, the newly derived matrices did not stimulate interleukin-1β expression over control cells. These studies suggest that chronic ethanol exposure induces oxidant stress and activates lung tissue remodeling characterized by increased expression of fibronectin by alveolar type II cells. The newly deposited fibronectin-enriched matrices may stimulate the expression of proinflammatory cytokines in monocytic cells recruited to the lung after injury thereby explaining the priming effects of ethanol.
An alcohol use disorder (AUD) is associated with an increased susceptibility to respiratory infection and injury and, upon hospitalization, higher mortality rates. Studies in model systems show effects of alcohol on mitochondrial function, lipid metabolism and antioxidant systems. The present study applied high-resolution metabolomics to test for these changes in bronchoalveolar lavage fluid (BALF) of subjects with an AUD. Smokers were excluded to avoid confounding effects and compliance was verified by cotinine measurements. Statistically significant metabolic features, differentially expressed by control and AUD subjects, were identified by statistical and bioinformatic methods. The results show that fatty acid and acylcarnitine concentrations were increased in AUD subjects, consistent with perturbed mitochondrial and lipid metabolism. Decreased concentrations of methyl-donor compounds suggest altered one-carbon metabolism and oxidative stress. An accumulation of peptides suggests proteolytic activity, which could reflect altered epithelial barrier function. Two metabolites of possible microbial origin suggest subclinical bacterial infection. Furthermore, increased diacetylspermine suggests additional metabolic perturbations, which could contribute to dysregulated alveolar macrophage function and vulnerability to infection. Together, the results show an extended metabolic consequence of AUD in the bronchoalveolar space.
Background: We hypothesized that maternal alcohol use occurs in pregnancies that end prematurely and that in utero alcohol exposure is associated with an increased risk of morbidities of premature newborns.
Methods: In an observational study of mothers who delivered very low birth weight newborns (VLBW) ≤1,500 g, maternal alcohol use was determined via a standardized administered questionnaire. We compared the effect of maternal drinking on the odds of developing late-onset sepsis (LOS), bronchopulmonary dysplasia (BPD), death, BPD or Death days on oxygen or any morbidity (either LOS, BPD or death). The effect of drinking amounts (light versus heavy) was also evaluated.
Results: A total of 129 subjects who delivered 143 VLBW newborns were enrolled. Approximately 1 in 3 (34%) subjects reported drinking alcohol during the first trimester ("exposed"). Within the exposed group, 15% reported drinking ≥7. drinks/week ("heavy") and 85% of the subjects reported drinking < 7. drinks/week ("light"). When controlling for maternal age, drug or tobacco use during pregnancy and neonatal gestational age, any drinking increased the odds of BPD or Death and any morbidity. Furthermore, light or heavy drinking increased the odds of BPD or Death and any morbidity, whereas heavy drinking increased the odds of LOS.
Conclusions: In utero alcohol exposure during the first trimester occurred in 34% of VLBW newborns. Maternal drinking in the first trimester was associated with significantly increased odds of neonatal morbidity. Further studies are warranted to determine the full effect of . in utero alcohol exposure on the adverse outcomes of VLBW premature newborns.