Comprehensive Multi-omics Analysis Reveals Mitochondrial Stress as a Central Biological Hub for Spaceflight Impact.

Spaceflight is known to impose changes on human physiology with unknown molecular etiologies. To reveal these causes, we used a multi-omics, systems biology analytical approach using biomedical profiles from fifty-nine astronauts and data from NASA's GeneLab derived from hundreds of samples flown in space to determine transcriptomic, proteomic, metabolomic, and epigenetic responses to spaceflight. Overall pathway analyses on the multi-omics datasets showed significant enrichment for mitochondrial processes, as well as innate immunity, chronic inflammation, cell cycle, circadian rhythm, and olfactory functions. Importantly, NASA's Twin Study provided a platform to confirm several of our principal findings. Evidence of altered mitochondrial function and DNA damage was also found in the urine and blood metabolic data compiled from the astronaut cohort and NASA Twin Study data, indicating mitochondrial stress as a consistent phenotype of spaceflight.

Multi-System-Level Analysis Reveals Differential Expression of Stress Response-Associated Genes in Inflammatory Solar Lentigo.

Although the pathogenesis of solar lentigo (SL) involves chronic ultraviolet (UV) exposure, cellular senescence, and upregulated melanogenesis, underlying molecular-level mechanisms associated with SL remain unclear. The aim of this study was to investigate the gene regulatory mechanisms intimately linked to inflammation in SL. Skin samples from patients with SL with or without histological inflammatory features were obtained. RNA-seq data from the samples were analyzed via multiple analysis approaches, including exploration of core inflammatory gene alterations, identifying functional pathways at both transcription and protein levels, comparison of inflammatory module (gene clusters) activation levels, and analyzing correlations between modules. These analyses disclosed specific core genes implicated in oxidative stress, especially the upregulation of nuclear factor kappa B in the inflammatory SLs, while genes associated with protective mechanisms, such as SLC6A9, were highly expressed in the non-inflammatory SLs. For inflammatory modules, Extracellular Immunity and Mitochondrial Innate Immunity were exclusively upregulated in the inflammatory SL. Analysis of protein-protein interactions revealed the significance of CXCR3 upregulation in the pathogenesis of inflammatory SL. In conclusion, the upregulation of stress response-associated genes and inflammatory pathways in response to UV-induced oxidative stress implies their involvement in the pathogenesis of inflammatory SL.

Multi-System-Level Analysis with RNA-Seq on Pterygium Inflammation Discovers Association between Inflammatory Responses, Oxidative Stress, and Oxidative Phosphorylation.

A pterygium is a common conjunctival degeneration and inflammatory condition. It grows onto the corneal surface or limbus, causing blurred vision and cosmetic issues. Ultraviolet is a well-known risk factor for the development of a pterygium, although its pathogenesis remains unclear, with only limited understanding of its hereditary basis. In this study, we collected RNA-seq from both pterygial tissues and conjunctival tissues (as controls) from six patients (a total of twelve biological samples) and retrieved publicly available data, including eight pterygium samples and eight controls. We investigated the intrinsic gene regulatory mechanisms closely linked to the inflammatory reactions of pterygiums and compared Asian (Korea) and the European (Germany) pterygiums using multiple analysis approaches from different perspectives. The increased expression of antioxidant genes in response to oxidative stress and DNA damage implies an association between these factors and pterygium development. Also, our comparative analysis revealed both similarities and differences between Asian and European pterygiums. The decrease in gene expressions involved in the three primary inflammatory signaling pathways-JAK/STAT, MAPK, and NF-kappa B signaling-suggests a connection between pathway dysfunction and pterygium development. We also observed relatively higher activity of autophagy and antioxidants in the Asian group, while the European group exhibited more pronounced stress responses against oxidative stress. These differences could potentially be necessitated by energy-associated pathways, specifically oxidative phosphorylation.

Microbial dysbiosis and the host airway epithelial response: insights into HIV-associated COPD using multi'omics profiling.

BACKGROUND: People living with HIV (PLWH) are at increased risk of developing Chronic Obstructive Pulmonary Disease (COPD) independent of cigarette smoking. We hypothesized that dysbiosis in PLWH is associated with epigenetic and transcriptomic disruptions in the airway epithelium. METHODS: Airway epithelial brushings were collected from 18 COPD + HIV + , 16 COPD - HIV + , 22 COPD + HIV - and 20 COPD - HIV - subjects. The microbiome, methylome, and transcriptome were profiled using 16S sequencing, Illumina Infinium Methylation EPIC chip, and RNA sequencing, respectively. Multi 'omic integration was performed using Data Integration Analysis for Biomarker discovery using Latent cOmponents. A correlation > 0.7 was used to identify key interactions between the 'omes. RESULTS: The COPD + HIV -, COPD -HIV + , and COPD + HIV + groups had reduced Shannon Diversity (p = 0.004, p = 0.023, and p = 5.5e-06, respectively) compared to individuals with neither COPD nor HIV, with the COPD + HIV + group demonstrating the most reduced diversity. Microbial communities were significantly different between the four groups (p = 0.001). Multi 'omic integration identified correlations between Bacteroidetes Prevotella, genes FUZ, FASTKD3, and ACVR1B, and epigenetic features CpG-FUZ and CpG-PHLDB3. CONCLUSION: PLWH with COPD manifest decreased diversity and altered microbial communities in their airway epithelial microbiome. The reduction in Prevotella in this group was linked with epigenetic and transcriptomic disruptions in host genes including FUZ, FASTKD3, and ACVR1B.

Airway Aging and Methylation Disruptions in HIV-associated Chronic Obstructive Pulmonary Disease.

Rationale: Age-related diseases like chronic obstructive pulmonary disease (COPD) occur at higher rates in people living with human immunodeficiency virus (PLWH) than in uninfected populations. Objectives: To identify whether accelerated aging can be observed in the airways of PLWH with COPD, manifest by a unique DNA methylation signature. Methods: Bronchial epithelial brushings from PLWH with and without COPD and HIV-uninfected adults with and without COPD (N = 76) were profiled for DNA methylation and gene expression. We evaluated global Alu and LINE-1 methylation and calculated the epigenetic age using the Horvath clock and the methylation telomere length estimator. To identify genome-wide differential DNA methylation and gene expression associated with HIV and COPD, robust linear models were used followed by an expression quantitative trait methylation (eQTM) analysis. Measurements and Main Results: Epigenetic age acceleration and shorter methylation estimates of telomere length were found in PLWH with COPD compared with PLWH without COPD and uninfected patients with and without COPD. Global hypomethylation was identified in PLWH. We identified 7,970 cytosine bases located next to a guanine base (CpG sites), 293 genes, and 9 expression quantitative trait methylation-gene pairs associated with the interaction between HIV and COPD. Actin binding LIM protein family member 3 (ABLIM3) was one of the novel candidate genes for HIV-associated COPD highlighted by our analysis. Conclusions: Methylation age acceleration is observed in the airway epithelium of PLWH with COPD, a process that may be responsible for the heightened risk of COPD in this population. Their distinct methylation profile, differing from that observed in patients with COPD alone, suggests a unique pathogenesis to HIV-associated COPD. The associations warrant further investigation to establish causality.

Expression of AKT1 Related with Clinicopathological Parameters in Clear Cell Renal Cell Carcinoma.

Pathways such as VEGF, EGF and mTOR are known to be one of the major mechanisms of tumorigenesis including kidney cancer. To identify potential signaling pathway proteins, we performed differential/correlation analyses of mTOR-associated genes from three public datasets. AKT1 protein, one of the PI3K/AKT/mTOR pathways, turned out to be the potential by showing a consistent discrepancy between ccRCC-associated conditions as well as strong correlation with other mTOR-associated genes across the datasets. Then, we analyzed how AKT1 alteration affects clear cell renal cell carcinoma. The pathology of 58 kidney cancer patients was constructed to analyze the relationship between the expression level of AKT1 through immunohistochemical staining and their clinicopathological data. Gender, age and TNM stage did not show significant results. AKT1 is a known oncogene. However, in this study, high expression of AKT1 showed a slight correlation with lower WHO/ISUP grade, longer recurrence-free and progression-free survival rates.

Changes in Emergency Department Visits, Diagnostic Groups, and 28-Day Mortality Associated With the COVID-19 Pandemic: A Territory-Wide, Retrospective, Cohort Study.

STUDY OBJECTIVE: We aimed to evaluate and characterize the scale and relationships of emergency department (ED) visits and excess mortality associated with the early phase of the COVID-19 pandemic in the territory of Hong Kong. METHODS: We conducted a territory-wide, retrospective cohort study to compare ED visits and the related impact of the COVID-19 pandemic on mortality. All ED visits at 18 public acute hospitals in Hong Kong between January 1 and August 31 of 2019 (n=1,426,259) and 2020 (n=1,035,562) were included. The primary outcome was all-cause mortality in the 28 days following an ED visit. The secondary outcomes were weekly number of ED visits and diagnosis-specific mortality. RESULTS: ED visits decreased by 27.4%, from 1,426,259 in 2019 to 1,035,562 in 2020. Overall period mortality increased from 28,686 (2.0%) in 2019 to 29,737 (2.9%) in 2020. The adjusted odds ratio for 28-day, all-cause mortality in the pandemic period of 2020 relative to 2019 was 1.26 (95% confidence interval 1.24 to 1.28). Both sexes, age more than 45 years, all triage categories, all social classes, all ED visit periods, epilepsy (odds ratio 1.58, 95% confidence interval 1.20 to 2.07), lower respiratory tract infection, and airway disease had higher adjusted ORs for all-cause mortality. CONCLUSION: A significant reduction in ED visits in the first 8 months of the COVID-19 pandemic was associated with an increase in deaths certified in the ED. The government must make provisions to encourage patients with alarming symptoms, mental health conditions, and comorbidities to seek timely emergency care, regardless of the pandemic.

Distinct Function of Mediator Subunits in Fungal Development, Stress Response, and Secondary Metabolism in Maize Pathogen Fusarium verticillioides.

Mediator is a nucleus-localized, multisubunit protein complex highly conserved across eukaryotes. It interacts with RNA polymerase II transcription machinery as well as various transcription factors to regulate gene expression. However, systematic characterization of the Mediator complex has not been performed in filamentous fungi. In our study, the goal was to investigate key biological functions of Mediator subunits in a mycotoxigenic plant pathogen Fusarium verticillioides. Although there is some level of divergence in the constituent subunits, the overall structure was conserved between Saccharomyces cerevisiae and F. verticillioides. We generated 11 Mediator subunit deletion mutants and characterized vegetative growth, conidia formation, environmental stress response, carbon and fatty acid use, virulence, and fumonisin B1 (FB1) biosynthesis. Each Mediator subunit deletion mutant showed deficiencies in at least three of the phenotypes tested, suggesting that each subunit has different principal functions in F. verticillioides development, metabolism, and virulence. The deletion of FvMed1 led to increased FB1 production, and we confirmed that FvMed1 is transported from the nucleus to the cytoplasm under fumonisin-producing conditions. Taken together, our study characterized various important functional roles for Mediator subunits in F. verticillioides and suggests that select subunits can perform unique cytoplasmic functions independent of the core Mediator in fungal nucleus.

The Urine Anion Gap: Common Misconceptions.

Two papers, one in 1986 and another one in 1988, reported a strong inverse correlation between urinary anion gap (UAG) and urine ammonia excretion (UNH4) in patients with metabolic acidosis and postulated that UAG could be used as an indirect measure of UNH4 This postulation has persisted until now and is widely accepted. In this review, we discuss factors regulating UAG and examine published evidence to uncover errors in the postulate and the design of the original studies. The essential fact is that, in the steady state, UAG reflects intake of Na, K, and Cl. Discrepancy between intake and urinary output of these electrolytes (i.e, UAG) indicates selective extrarenal loss of these electrolytes or nonsteady state. UNH4 excretion, which depends, in the absence of renal dysfunction, mainly on the daily acid load, has no consistent relationship to UAG either theoretically or in reality. Any correlation between UAG and UNH4, when observed, was a fortuitous correlation and cannot be extrapolated to other situations. Furthermore, the normal value of UAG has greatly increased over the past few decades, mainly due to increases in dietary intake of potassium and widespread use of sodium salts with anions other than chloride as food additives. The higher normal values of UAG must be taken into consideration in interpreting UAG.

The effect of aquatic High Intensity Interval Training on cardiometabolic and physical health markers in women: A systematic review and meta-analysis.

BACKGROUND: We performed a meta-analysis of randomized controlled trials (RCTs) assessing the effect of Aquatic High Intensity Interval Training (AHIIT) on cardiometabolic and physical health markers in women. METHODS: Systematic search used 7 databases (MEDLINE, PubMed, SPORTDiscus, Cochrane, Embase, CINAL complete, PsycINFO). The Physiotherapy Evidence Database (PEDro) score was used to evaluate the methodological quality of the studies. Clinical trials compared AHIIT with a control group that receive no exercise training. We integrated randomized controlled trials published in English, and participants were women aged ≥18 years. The outcome of interest was the change in cardiometabolic and physical health markers. RESULTS: Among 242 articles screened, 18 articles (13 trials) were included in this meta-analysis comparing AHIIT (n = 261) with a control group (n = 215). The median PEDro score was 5.5 out of 10 (range, 4-8). AHIIT significantly improved peak oxygen uptake (Hedges' g 0.610; 95% CI 0.277-0.943; P < 0.001), reduced resting heart rate (Hedges' g -0.495; 95% CI -0.866 to -0.124; P < 0.05), as well as chair to stand test. (Hedges' g 0.548; 95% CI 0.019 to 1.077; P < 0.05). CONCLUSION: AHIIT has a moderate effect in improving cardiometabolic and physical health markers in women.

Occurrence of Accelerated Epigenetic Aging and Methylation Disruptions in Human Immunodeficiency Virus Infection Before Antiretroviral Therapy.

BACKGROUND: Whether accelerated aging develops over the course of chronic human immunodeficiency virus (HIV) infection or can be observed before significant immunosuppression on is unknown. We studied DNA methylation in blood to estimate cellular aging in persons living with HIV (PLWH) before the initiation of antiretroviral therapy (ART). METHODS: A total of 378 ART-naive PLWH who had CD4 T-cell counts >500/µL and were enrolled in the Strategic Timing of Antiretroviral Therapy trial (Pulmonary Substudy) were compared with 34 HIV-negative controls. DNA methylation was performed using the Illumina MethylationEPIC BeadChip. Differentially methylated positions (DMPs) and differentially methylated regions (DMRs) in PLWH compared with controls were identified using a robust linear model. Methylation age was calculated using a previously described epigenetic clock. RESULTS: There were a total of 56 639 DMPs and 6103 DMRs at a false discovery rate of <0.1. The top 5 DMPs corresponded to genes NLRC5, VRK2, B2M, and GPR6 and were highly enriched for cancer-related pathways. PLWH had significantly higher methylation age than HIV-negative controls (P = .001), with black race, low CD4 and high CD8 T-cell counts, and duration of HIV being risk factors for age acceleration. CONCLUSIONS: PLWH before the initiation of ART and with preserved immune status show evidence of advanced methylation aging.

IL-4Rα blockade reduces influenza-associated morbidity in a murine model of allergic asthma.

BACKGROUND: Asthma was identified as the most common comorbidity in hospitalized patients during the 2009 H1N1 influenza pandemic. We determined using a murine model of allergic asthma whether these mice experienced increased morbidity from pandemic H1N1 (pH1N1) viral infection and whether blockade of interleukin-4 receptor α (IL-4Rα), a critical mediator of Th2 signalling, improved their outcomes. METHODS: Male BALB/c mice were intranasally sensitized with house dust mite antigen (Der p 1) for 2 weeks; the mice were then inoculated intranasally with a single dose of pandemic H1N1 (pH1N1). The mice were administered intraperitoneally anti-IL-4Rα through either a prophylactic or a therapeutic treatment strategy. RESULTS: Infection with pH1N1 of mice sensitized to house dust mite (HDM) led to a 24% loss in weight by day 7 of infection (versus 14% in non-sensitized mice; p < .05). This was accompanied by increased viral load in the airways and a dampened anti-viral host responses to the infection. Treatment of HDM sensitized mice with a monoclonal antibody against IL-4Rα prior to or following pH1N1 infection prevented the excess weight loss, reduced the viral load in the lungs and ameliorated airway eosinophilia and systemic inflammation related to the pH1N1 infection. CONCLUSION: Together, these data implicate allergic asthma as a significant risk factor for H1N1-related morbidity and reveal a potential therapeutic role for IL-4Rα signalling blockade in reducing the severity of influenza infection in those with allergic airway disease.

Epigenetic marker of telomeric age is associated with exacerbations and hospitalizations in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is an age-related condition that has been associated with early telomere attrition; the clinical implications of telomere shortening in COPD are not well known. In this study we aimed to determine the relationship of the epigenetic regulation of telomeric length in peripheral blood with the risk of exacerbations and hospitalization in patients with COPD. METHODS: Blood DNA methylation profiles were obtained from 292 patients with COPD enrolled in the placebo arm of the Macrolide Azithromycin to Prevent Rapid Worsening of Symptoms Associated with Chronic Obstructive Pulmonary Disease (MACRO) Study and who were followed for 1-year. We calculated telomere length based on DNA methylation markers (DNAmTL) and related this biomarker to the risk of exacerbation and hospitalization and health status (St. George Respiratory Questionnaire [SGRQ]) score over time using a Cox proportional hazards model. We also used linear models to investigate the associations of DNAmTL with the rates of exacerbation and hospitalization (adjusted for chronological age, lung function, race, sex, smoking, body mass index and cell composition). RESULTS: Participants with short DNAmTL demonstrated increased risk of exacerbation (P = 0.02) and hospitalization (P = 0.03) compared to those with longer DNAmTL. DNAmTL age acceleration was associated with higher rates of exacerbation (P = 1.35 × 10-04) and hospitalization (P = 5.21 × 10-03) and poor health status (lower SGRQ scores) independent of chronological age (P = 0.03). CONCLUSION: Telomeric age based on blood DNA methylation is associated with COPD exacerbation and hospitalization and thus a promising biomarker for poor outcomes in COPD.

Scedar: A scalable Python package for single-cell RNA-seq exploratory data analysis.

In single-cell RNA-seq (scRNA-seq) experiments, the number of individual cells has increased exponentially, and the sequencing depth of each cell has decreased significantly. As a result, analyzing scRNA-seq data requires extensive considerations of program efficiency and method selection. In order to reduce the complexity of scRNA-seq data analysis, we present scedar, a scalable Python package for scRNA-seq exploratory data analysis. The package provides a convenient and reliable interface for performing visualization, imputation of gene dropouts, detection of rare transcriptomic profiles, and clustering on large-scale scRNA-seq datasets. The analytical methods are efficient, and they also do not assume that the data follow certain statistical distributions. The package is extensible and modular, which would facilitate the further development of functionalities for future requirements with the open-source development community. The scedar package is distributed under the terms of the MIT license at https://pypi.org/project/scedar.

The impact of Sambucus nigra L. extract on inflammation, oxidative stress and tissue remodeling in a rat model of lipopolysaccharide-induced subacute rhinosinusitis.

Rhinosinusitis is a common disorder related to inflammation of paranasal sinuses and nasal cavity mucosa. Herbal medicines could be an option in the treatment of rhinosinusitis due to their anti-inflammatory and anti-oxidative properties. The study aims to investigate the effect of intranasal Sambucus nigra L. subsp. nigra (SN) extract against inflammation, oxidative stress, and tissue remodeling in nasal and sinus mucosa, but also in serum, lungs, and brain, in Wistar rat model of subacute sinonasal inflammation induced by local administration of lipopolysaccharides (LPS), from Escherichia Coli. The cytokines (TNF-α, IL-1ß, IL-6) and oxidative stress (malondialdehyde) in nasal mucosa, blood, lungs, and brain were analyzed. In addition, a histopathological examination was performed, and NF-kB, MMP2, MMP9, TIMP1 expressions were also evaluated in nasal mucosa. Both doses of LPS increased the production of cytokines in all the investigated tissues, especially in the nasal mucosa and blood (p < 0.01 and p < 0.05), and stimulated their secretion in the lungs, and partially in the brain. Malondialdehyde increased in all the investigated tissues (p < 0.01 and p < 0.05). In parallel, upregulation of NF-kB and MMP2 expressions with downregulation of TIMP1, particularly at high dose of LPS, was observed. SN extract reduced the local inflammatory response, maintained low levels of IL-6, TNF-α, and IL-1ß. In lungs, SN reduced all cytokines levels while in the brain, the protective effect was noticed only on IL-6. Additionally, SN diminished lipid peroxidation and downregulated NF-kB in animals exposed to a low dose of LPS, with increased TIMP1 expression, while in animals treated with a high dose of LPS, SN increased NF-kB, MMP2, and MMP9 levels. In conclusion, SN extract diminished the inflammatory response, reduced generation of reactive oxygen species (ROS) and, influenced MMPs expressions, suggesting the benficial effect of SN extract on tissue remodeling in subacute rhinosinusitis and on systemic inflammatory response.

L-lactic acidosis: pathophysiology, classification, and causes; emphasis on biochemical and metabolic basis.

L-lactic acidosis (L-LA) is the most common cause of metabolic acidosis in the critical care setting, which has been associated with a large increase in mortality. The purpose of this article is to provide clinicians with an overview of the biochemical and metabolic background required to understand the different pathophysiological mechanisms that may lead to the development of L-LA. We propose a classification based on whether the pathophysiology of L-LA is due predominantly to increased production or decreased removal of L-lactic acid. In this article, we provide an overview of the biochemical and metabolic aspects of glucose oxidation, the production and removal of L-lactic acid, and a discussion of the pathophysiology of the various causes of L-LA.

Sputum Microbiome Is Associated with 1-Year Mortality after Chronic Obstructive Pulmonary Disease Hospitalizations.

Rationale: Lung dysbiosis promotes airway inflammation and decreased local immunity, potentially playing a role in the pathogenesis of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Objectives: We sought to determine the relationship between sputum microbiome at the time of AECOPD hospitalization and 1-year mortality in a COPD cohort. Methods: We used sputum samples from 102 patients hospitalized because of AECOPD. All subjects were followed for 1 year after discharge. The microbiome profile was assessed through sequencing of 16S rRNA gene. Microbiome analyses were performed according to 1-year mortality status. To investigate the effect of α-diversity measures and taxon features on time to death, we applied Cox proportional hazards regression models and obtained hazard ratios (HRs) associated with these variables. Measurements and Main Results: We observed significantly lower values of α-diversity (richness, Shannon index, evenness, and Faith's Phylogenetic Diversity) among nonsurvivors (n = 19, 18.6%) than survivors (n = 83, 81.4%). ß-Diversity analysis also demonstrated significant differences between both groups (adjusted permutational multivariate ANOVA, P = 0.010). The survivors had a higher relative abundance of Veillonella; in contrast, nonsurvivors had a higher abundance of Staphylococcus. The adjusted HRs for 1-year mortality increased significantly with decreasing α-diversity. We also observed lower survival among patients in whom sputum samples were negative for Veillonella (HR, 13.5; 95% confidence interval, 4.2-43.9; P < 0.001) or positive for Staphylococcus (HR, 7.3; 95% confidence interval, 1.6-33.2; P = 0.01). Conclusions: The microbiome profile of sputum in AECOPD is associated with 1-year mortality and may be used to identify subjects with a poor prognosis at the time of hospitalization.

The pharmacogenomics of inhaled corticosteroids and lung function decline in COPD.

Inhaled corticosteroids (ICS) are widely prescribed for patients with chronic obstructive pulmonary disease (COPD), yet have variable outcomes and adverse reactions, which may be genetically determined. The primary aim of the study was to identify the genetic determinants for forced expiratory volume in 1 s (FEV1) changes related to ICS therapy.In the Lung Health Study (LHS)-2, 1116 COPD patients were randomised to the ICS triamcinolone acetonide (n=559) or placebo (n=557) with spirometry performed every 6 months for 3 years. We performed a pharmacogenomic genome-wide association study for the genotype-by-ICS treatment effect on 3 years of FEV1 changes (estimated as slope) in 802 genotyped LHS-2 participants. Replication was performed in 199 COPD patients randomised to the ICS, fluticasone or placebo.A total of five loci showed genotype-by-ICS interaction at p<5×10-6; of these, single nucleotide polymorphism (SNP) rs111720447 on chromosome 7 was replicated (discovery p=4.8×10-6, replication p=5.9×10-5) with the same direction of interaction effect. ENCODE (Encyclopedia of DNA Elements) data revealed that in glucocorticoid-treated (dexamethasone) A549 alveolar cell line, glucocorticoid receptor binding sites were located near SNP rs111720447. In stratified analyses of LHS-2, genotype at SNP rs111720447 was significantly associated with rate of FEV1 decline in patients taking ICS (C allele ß 56.36 mL·year-1, 95% CI 29.96-82.76 mL·year-1) and in patients who were assigned to placebo, although the relationship was weaker and in the opposite direction to that in the ICS group (C allele ß -27.57 mL·year-1, 95% CI -53.27- -1.87 mL·year-1).The study uncovered genetic factors associated with FEV1 changes related to ICS in COPD patients, which may provide new insight on the potential biology of steroid responsiveness in COPD.

Alkali delivery in chronic hemodialysis: Would more acetate be helpful?

The dialysate alkali used in hemodialysis to replace low body alkali levels in end stage renal disease (ESRD) patients has changed over time from bicarbonate to acetate and finally back to bicarbonate with a small addition of acetate. The ideal way to replace alkali in dialysis patients remains uncertain. Elsewhere in this issue of the journal, Sargent and Gennari, who have contributed greatly to our understanding of dialysis and acid-base kinetics, suggest that decreasing the currently used concentration of bicarbonate while increasing concentration of acetate in the dialysate may be a much more physiological approach to alkali delivery during hemodialysis. These recommendations are based on results from a series of hemodialysis simulations using mathematical theoretical methods, with the assumption that acetate metabolism will be sufficiently delayed with the higher acetate dialysate and reduce the rate of correction of metabolic acidosis during dialysis. Although valuable in calling attention to the issues surrounding alkali repletion during hemodialysis, these postulations should be tested in clinical trials. We believe, however, that the available evidence suggests that the rate of gain of bicarbonate during dialysis with the higher acetate dialysate would not be slower and that the replacement of some dialysate bicarbonate with acetate will not alter alkali accretion or intradialytic pH.