Novel Odoribacter splanchnicus Strain and Its Outer Membrane Vesicles Exert Immunoregulatory Effects in vitro.

Front Microbiol. 2020;11:575455

Authors: Hiippala K, Barreto G, Burrello C, Diaz-Basabe A, Suutarinen M, Kainulainen V, Bowers JR, Lemmer D, Engelthaler DM, Eklund KK, Facciotti F, Satokari R

Abstract
Odoribacter splanchnicus, belonging to the order Bacteroidales, is a common, short-chain fatty acid producing member of the human intestinal microbiota. A decreased abundance of Odoribacter has been linked to different microbiota-associated diseases, such as non-alcoholic fatty liver disease, cystic fibrosis and inflammatory bowel disease (IBD). The type strain of O. splanchnicus has been genome-sequenced, but otherwise very little is known about this anaerobic bacterium. The species surfaces in many microbiota studies and, consequently, comprehension on its interactions with the host is needed. In this study, we isolated a novel strain of O. splanchnicus from a healthy fecal donor, identified it by genome sequencing and addressed its adhesive, epithelium reinforcing and immunoregulatory properties. Our results show that O. splanchnicus strain 57 is non-adherent to enterocytes or mucus, does not reinforce nor compromise Caco-2 monolayer integrity and most likely harbors penta-acylated, less endotoxic lipid A as part of its lipopolysaccharide (LPS) structure based on the lack of gene lpxM and in vitro results on low-level NF-κB activity. The studies by transmission electron microscopy revealed that O. splanchnicus produces outer membrane vesicles (OMV). O. splanchnicus cells, culture supernatant i.e., spent medium or OMVs did not induce interleukin-8 (IL-8) response in HT-29 enterocyte cells suggesting a very low proinflammatory capacity. On the contrary, the treatment of HT-29 cells with O. splanchnicus cells, spent medium or OMVs prior to exposure to Escherichia coli LPS elicited a significant decrease in IL-8 production as compared to E. coli LPS treatment alone. Moreover, O. splanchnicus spent supernatant induced IL-10 production by immune cells, suggesting anti-inflammatory activity. Our in vitro findings indicate that O. splanchnicus and its effector molecules transported in OMVs could potentially exert anti-inflammatory action in the gut epithelium. Taken together, O. splanchnicus seems to be a commensal with a primarily beneficial interaction with the host.

PMID: 33281770 [PubMed]

Rescue from Pseudomonas aeruginosa airway infection via stem cell transplantation.

Mol Ther. 2020 Dec 03;:

Authors: Brinkert K, Hedtfeld S, Burhop A, Gastmeier R, Gad P, Wedekind D, Kloth C, Rothschuh J, Lachmann N, Hetzel M, Jirmo AC, Lopez-Rodriguez E, Brandenberger C, Hansen G, Schambach A, Ackermann M, Tümmler B, Munder A

Abstract
Cystic fibrosis is caused by mutations in the CFTR gene, which lead to impaired ion transport in epithelial cells. Although lung failure due to chronic infection is the major comorbidity in individuals with cystic fibrosis, the role of CFTR in non-epithelial cells has not been definitely resolved. Given the important role of host defense cells, we evaluated the Cftr deficiency in pulmonary immune cells by hematopoietic stem cell transplantation in cystic fibrosis mice. We transplanted healthy bone marrow stem cells and could reveal a stable chimerism of wild type cells in peripheral blood. The outcome of stem cell transplantation and the impact of healthy immune cells were evaluated in acute Pseudomonas aeruginosa airway infection. Here, mice transplanted with wild type cells displayed better survival, lower lung bacterial numbers and a milder disease course. This improved physiology of infected mice correlated with successful intrapulmonary engraftment of graft-derived alveolar macrophages, as seen by immunofluorescence microscopy and flow cytometry of graft-specific leucocyte surface marker CD45 and macrophage marker CD68. Given the beneficial effect of hematopoietic stem cell transplantation and stable engraftment of monocyte-derived CD68-positive macrophages, we conclude that replacement of mutant Cftr macrophages attenuate airway infection in cystic fibrosis mice.

PMID: 33279724 [PubMed - as supplied by publisher]

CFTR plays an important role in the regulation of vascular resistance and high-fructose/salt-diet induced hypertension in mice.

J Cyst Fibros. 2020 Dec 02;:

Authors: Zhang YP, Ye LL, Yuan H, Duan DD

Abstract
BACKGROUND: The pathophysiological roles of cystic fibrosis transmembrane-conductance regulator (CFTR) Cl- channels in the regulation of blood pressure (BP) remain controversial. Here we studied the function of CFTR Cl- channels in regulation of BP and in the high-fructose-salt-diet (HFSD) induced hypertension in mice.
METHODS: The systolic, diastolic and mean BP (SBP, DBP and MBP, respectively) were continuously monitored from unrestricted conscious wild-type (cftr+/+) FVB and CFTR-knockout (cftr-/-) mice (8-week old, male). HFSD (64.7% fructose, 2% NaCl water) or control normal starch diet (CNSD, 58.9% corn starch, 0 NaCl water) was given for 8 weeks and vascular Doppler were performed. Real-time PCR and Western blot were used to examine mRNA and protein expression, respectively.
RESULTS: The aortic stiffness, daytime and nighttime SBP, DBP, and MBP of the cftr-/- mice were significantly higher than those in the age- and gender-matched cftr+/+ mice, which is consistent with the findings of increased vascular resistance in cystic fibrosis patients. The aortic stiffness, daytime and nighttime SBP, DBP, and MBP of cftr+/+ mice fed with HFSD were all significantly higher than those fed with CNSD. Importantly, HFSD caused a significant decrease in mRNA and protein expression of WINK1, WINK4 and CFTR in aorta and mesenteric arteries, but not in the kidney, corroborating that HSFD-induced downregulation of WINKs and loss of CFTR function specifically in the arteries may mediate the increased BP.
CONCLUSIONS: CFTR regulates peripheral arterial resistance and BP in vivo. HFSD-induced CFTR downregulation specifically in the arteries may be a novel mechanism for hypertension.

PMID: 33279469 [PubMed - as supplied by publisher]

Clinical evaluation of an evidence-based method based on food characteristics to adjust pancreatic enzyme supplements dose in cystic fibrosis.

J Cyst Fibros. 2020 Dec 02;:

Authors: Calvo-Lerma J, Boon M, Colombo C, de Koning B, Asseiceira I, Garriga M, Roca M, Claes I, Bulfamante A, Walet S, Pereira L, Ruperto M, Masip E, Asensio-Grau A, Giana A, Affourtit P, Heredia A, Vicente S, Andrés A, de Boeck K, Hulst J, Ribes-Koninckx C

Abstract
BACKGROUND: Patients with cystic fibrosis (CF) and pancreatic insufficiency need pancreatic enzyme replacement therapy (PERT) for dietary lipids digestion. There is limited evidence for recommending the adequate PERT dose for every meal, and controlling steatorrhea remains a challenge. This study aimed to evaluate a new PERT dosing method supported by a self-management mobile-app.
METHODS: Children with CF recruited from 6 European centres were instructed to use the app, including an algorithm for optimal PERT dosing based on in vitro digestion studies for every type of food. At baseline, a 24h self-selected diet was registered in the app, and usual PERT doses were taken by the patient. After 1 month, the same diet was followed, but PERT doses were indicated by the app. Change in faecal fat and coefficient of fat absorption (CFA) were determined.
RESULTS: 58 patients (median age 8.1 years) participated. Baseline fat absorption was high: median CFA 96.9%, median 2.4g faecal fat). After intervention CFA did not significantly change, but range of PERT doses was reduced: interquartile ranges narrowing from 1447-3070 at baseline to 1783-2495 LU/g fat when using the app. Patients with a low baseline fat absorption (CFA<90%, n=12) experienced significant improvement in CFA after adhering to the recommended PERT dose (from 86.3 to 94.0%, p=0.031).
CONCLUSION: the use of a novel evidence-based PERT dosing method, based on in vitro fat digestion studies incorporating food characteristics, was effective in increasing CFA in patients with poor baseline fat absorption and could safely be implemented in clinical practice.

PMID: 33279468 [PubMed - as supplied by publisher]

ACT with CF: A telehealth and in-person feasibility study to address anxiety and depressive symptoms among people with cystic fibrosis.

J Cyst Fibros. 2020 Dec 02;:

Authors: O'Hayer CV, O'Loughlin CM, Nurse CN, Smith PJ, Stephen MJ

Abstract
BACKGROUND: Anxiety and depressive symptoms are common among individuals with cystic fibrosis (CF) and are associated with decreased lung function [3], quality of life [4], and treatment adherence [2]. However, CF-specific targeted psychotherapeutic interventions are lacking. This study examined whether Acceptance and Commitment Therapy (ACT) [7], delivered via telehealth, would address this need and improve clinical symptoms. Telehealth is ideal for CF patients, given exposure precautions and frequent hospitalization. ACT emphasizes acceptance, thereby reducing avoidance of anxiety and depressive symptoms associated with CF. It was hypothesized that our ACT with CF protocol [11] would also improve lung function among people with CF.
METHODS: Participants were 28 adults with CF and elevated clinical symptoms who completed 6 ACT with CF sessions. They completed measures of depression, anxiety, and cognitive fusion at baseline, post-intervention, and at a 3-month follow-up. Lung function was calculated 3 months pre- and 3 months post-treatment.
RESULTS: The majority of participants selected treatment via telehealth (n = 22; 79%). 96% of participants (n=27) completed all 6 sessions, with 93% (n=26) voicing a strong desire to continue treatment with ACT. 79% of the sample (n=22) indicated, after just 1 session of ACT with CF, that treatment seemed logical and feeling confident that it would reduce symptoms of anxiety and depression. ACT with CF was associated with a statistically significant reduction in a composite score of psychological distress from pre to post treatment, corresponding to a large standardized effect size, that was not sustained at 3 months. Telehealth-delivered ACT with CF was as effective as in-person. Reductions in cognitive fusion were strongly related to improvements in psychosocial functioning. This is particularly promising as it reflects the proposed mechanism of action of ACT. ACT with CF was also associated with increased FEV1/FVC ratio at post-treatment follow-up.
CONCLUSIONS: ACT with CF delivered via telehealth or in-person is a feasible and potentially effective treatment for improving anxiety and depressive symptoms, and increasing psychological flexibility via reductions in cognitive fusion. Due to the effect size associated with reduction in psychosocial distress, we are cautiously optimistic that ACT with CF will prove an effective treatment. Larger randomized controlled trials are needed to confirm the observed findings and further delineate the potential effects of ACT with CF on clinical outcomes among individuals with CF.

PMID: 33279467 [PubMed - as supplied by publisher]

The effect of self-efficacy, social support and quality of life on readiness for transition to adult care among adolescents with cystic fibrosis in Turkey.

J Pediatr Nurs. 2020 Dec 02;:

Authors: Torun T, Çavuşoğlu H, Doğru D, Özçelik U, Ademhan Tural D

Abstract
PURPOSE: The aim of this study is to examine the effects of self-efficacy, social support and quality of life on readiness for transition to adult care in adolescents with cystic fibrosis.
DESIGN AND METHODS: A descriptive and cross-sectional study design was used. Data were collected from 50 adolescent between 14 and 17 years old with cystic fibrosis, by using The Transition Readiness Assessment Questionnaire, Social Support Appraisals Scale for Children, Self-Efficacy Questionnaire for Children and health-related quality-of-life instrument, the KIDSCREEN-10.
RESULTS: A positive correlation was found between the readiness levels of adolescents for transition to adult care and self-efficacy levels. In path analysis, self-efficacy was found to have a significant effect on the level of readiness for transition to adult care. There was not statistically significant relationship between the level of readiness for transition to adult care and health-related quality of life and perceived social support. Path analysis revealed that health-related quality of life and perceived social support had significant effects on the self-efficacy levels of adolescents.
CONCLUSIONS: Self-efficacy were associated with readiness for the transition to adult care. Although perceived social support and quality of life were not related with transition readiness these variables had significant effects on perceived self-efficacy, which was determined as a factor affecting the readiness for the transition to adult care.
PRACTICE IMPLICATIONS: In adolescents with cystic fibrosis, self-efficacy, social support and quality of life levels should be taken into account when planning preparation programs for transition to adult care.

PMID: 33279319 [PubMed - as supplied by publisher]

Myeloid arginase-1 controls excessive inflammation and modulates T cell responses in Pseudomonas aeruginosa pneumonia.

Immunobiology. 2020 Nov 24;226(1):152034

Authors: Haydar D, Gonzalez R, Garvy BA, Garneau-Tsodikova S, Thamban Chandrika N, Bocklage TJ, Feola DJ

Abstract
Regulatory properties of macrophages associated with alternative activation serve to limit the exaggerated inflammatory response during pneumonia caused by Pseudomonas aeruginosa infection. Arginase-1 is an important effector of these macrophages believed to play an essential role in decreasing injury and promoting repair. We investigated the role of arginase-1 in the control of inflammatory immune responses to P. aeruginosa pneumonia in mice that exhibit different immunologic phenotypes. C57BL/6 mice with conditional knockout of the arginase-1 (Arg1) gene from myeloid cells (Arg1ΔM) or BALB/c mice treated with small molecule inhibitors of arginase were infected intratracheally with P. aeruginosa. Weight loss, mortality, bacterial clearance, and lung injury were assessed and compared, as were the characterization of immune cell populations over time post-infection. Myeloid arginase-1 deletion resulted in greater morbidity along with more severe inflammatory responses compared to littermate control mice. Arg1ΔM mice had greater numbers of neutrophils, macrophages, and lymphocytes in their airways and lymph nodes compared to littermate controls. Additionally, Arg1ΔM mice recovered from inflammatory lung injury at a significantly slower rate. Conversely, treatment of BALB/c mice with the arginase inhibitor S-(2-boronoethyl)-l-cysteine hydrochloride (BEC) did not change morbidity as defined by weight loss, but mice at day 10 post-infection treated with BEC had gained significantly more weight back than controls. Neutrophil and macrophage infiltration were similar between groups in the lung parenchyma, and neutrophil migration into the airways was reduced by BEC treatment. Differences seem to lie in the impact on T cell subset disposition. Arg1ΔM mice had increased total CD4+ T cell expansion in the lymph nodes, and increased T cell activation, IFNγ production, and IL-17 production in the lymph nodes, lung interstitium, and airways, while treatment with BEC had no impact on T cell activation or IL-17 production, but reduced the number of T cells producing IFNγ in the lungs. Lung injury scores were increased in the Arg1ΔM mice, but no differences were observed in the mice treated with pharmacologic arginase inhibitors. Overall, myeloid arginase production was demonstrated to be essential for control of damaging inflammatory responses associated with P. aeruginosa pneumonia in C57BL/6 mice, in contrast to a protective effect in the Th2-dominant BALB/c mice when arginase activity is globally inhibited.

PMID: 33278710 [PubMed - as supplied by publisher]

G970R-CFTR Mutation (c.2908G>C) Results Predominantly in a Splicing Defect.

Clin Transl Sci. 2020 Dec 05;:

Authors: Fidler MC, Buckley A, Sullivan JC, Statia M, Boj SF, Vries RGJ, Munck A, Higgins M, Zita MM, Negulescu P, van Goor F, De Boeck K

Abstract
In previous work, participants with a G970R mutation in cystic fibrosis transmembrane conductance regulator (CFTR) (c.2908G>C) had numerically lower sweat chloride responses during ivacaftor treatment than participants with other CFTR gating mutations. The objective of this substudy was to characterize the molecular defect of the G970R mutation in vitro and assess the benefit of ivacaftor in participants with this mutation. This substudy assessed sweat chloride, spirometry findings, and nasal potential difference on and off ivacaftor treatment in 3 participants with a G970R/F508del genotype. Intestinal organoids derived from rectal biopsy specimens were used to assess ivacaftor response ex vivo and conduct messenger RNA splice and protein analyses. No consistent or meaningful trends were observed between on- and off-treatment clinical assessments. Organoids did not respond to ivacaftor in forskolin-induced swelling assays; no mature CFTR protein was detected in Western blots. Organoid RNA analysis demonstrated that 3 novel splice variants were created by G970R-CFTR: exon 17 truncation, exons 13-15 and 17 skipping, and intron 17 retention. Functional and molecular analyses indicated that the c.2908G>C mutation caused a cryptic splicing defect. Organoids lacked an ex vivo response with ivacaftor and supported identification of the mechanism underlying the CFTR defect caused by c.2908G>C. Analysis of CFTR mutations indicated that cryptic splicing was a rare cause of mutation misclassification in engineered cell lines. This substudy used organoids as an alternative in vitro model for mutations such as cryptic splice mutations that cannot be fully assessed using cDNA expressed in recombinant cell systems.

PMID: 33278322 [PubMed - as supplied by publisher]

Can we identify cystic fibrosis (CF) from skeletal remains?: A proposed differential diagnosis.

Anat Rec (Hoboken). 2020 Dec 05;:

Authors: Beasley MM, Remy CK

Abstract
Cystic fibrosis (CF) is the most common genetic disease within populations with European ancestry and affects approximately 60,000 individuals living in North America and Europe. With recent medical advancement, the life span of CF patients has been extended by decades and bone disease has been observed as a common complication of long-term survivors. In addition to bone disease and associated bone fracturing, living CF patients have a unique etiology of chronic sinusitis, which manifests as a medial bulge in the lateral walls of the nasal aperture, distinct from non-CF chronic sinusitis. We suggest that available data from medical literature is sufficient evidence to indicate that CF can be identified during skeletal analysis, but future work is needed to quantify the sensitivity of the lesions for confirming a CF diagnosis.

PMID: 33277945 [PubMed - as supplied by publisher]

Loss of FOXF1 expression promotes human lung-resident mesenchymal stromal cell migration via ATX/LPA/LPA1 signaling axis.

Sci Rep. 2020 Dec 04;10(1):21231

Authors: Cao P, Walker NM, Braeuer RR, Mazzoni-Putman S, Aoki Y, Misumi K, Wheeler DS, Vittal R, Lama VN

Abstract
Forkhead box F1 (FOXF1) is a lung embryonic mesenchyme-associated transcription factor that demonstrates persistent expression into adulthood in mesenchymal stromal cells. However, its biologic function in human adult lung-resident mesenchymal stromal cells (LR-MSCs) remain to be elucidated. Here, we demonstrate that FOXF1 expression acts as a restraint on the migratory function of LR-MSCs via its role as a novel transcriptional repressor of autocrine motility-stimulating factor Autotaxin (ATX). Fibrotic human LR-MSCs demonstrated lower expression of FOXF1 mRNA and protein, compared to non-fibrotic controls. RNAi-mediated FOXF1 silencing in LR-MSCs was associated with upregulation of key genes regulating proliferation, migration, and inflammatory responses and significantly higher migration were confirmed in FOXF1-silenced LR-MSCs by Boyden chamber. ATX is a secreted lysophospholipase D largely responsible for extracellular lysophosphatidic acid (LPA) production, and was among the top ten upregulated genes upon Affymetrix analysis. FOXF1-silenced LR-MSCs demonstrated increased ATX activity, while mFoxf1 overexpression diminished ATX expression and activity. The FOXF1 silencing-induced increase in LR-MSC migration was abrogated by genetic and pharmacologic targeting of ATX and LPA1 receptor. Chromatin immunoprecipitation analyses identified three putative FOXF1 binding sites in the 1.5 kb ATX promoter which demonstrated transcriptional repression of ATX expression. Together these findings identify FOXF1 as a novel transcriptional repressor of ATX and demonstrate that loss of FOXF1 promotes LR-MSC migration via the ATX/LPA/LPA1 signaling axis.

PMID: 33277571 [PubMed - as supplied by publisher]

YKL-40 as a clinical biomarker in adult patients with CF: Implications of a CHI3L1 single nucleotide polymorphism in disease severity.

J Cyst Fibros. 2020 Dec 01;:

Authors: Coriati A, Bouvet GF, Massé C, Ducruet T, Berthiaume Y

Abstract
BACKGROUND: YKL-40 (chitinase 3-like 1 gene; CHI3L1) is an inflammatory marker that is increased in the blood of patients with inflammatory diseases, including cystic fibrosis (CF). The objective of our study was to explore the relationship between circulating levels of YKL-40, selected CHI3L1 single nucleotide polymorphisms (SNPs) and the severity of CF disease.
METHODS: A prospective cohort of 188 adult patients with CF was established in 2015. Blood samples and clinical data were collected over 2 years to analyze the circulating levels of YKL-40 and to genotype selected CHI3L1 SNPs. We also looked for an association between these factors and clinical parameters.
RESULTS: We found that according to the serum YKL-40 concentration, the patients could be categorized into two distinct groups: low and high YKL-40. Compared to the patients in the low YKL-40 group, the patients in the high YKL-40 group had lower lung function (P < 0.001), a higher proportion of delF508 homozygote mutations (P= 0.027) and dysglycemia (P= 0.015). They were also more colonized with Pseudomonas aeruginosa (P= 0.003) and required more frequent antibiotic intravenous courses (P < 0.001). We also observed that patients expressing the C/C-rs4950928 genotype had higher levels of YKL-40 in their blood and were more frequently dysglycemic.
CONCLUSION: Our study suggests that YKL-40 could be a potential biomarker of CF disease severity. Furthermore, the CHI3L1 rs4950928 SNP could be a susceptible gene that could be used by CF health professionals to identify patients who are the most at risk of having a severe clinical profile.

PMID: 33277205 [PubMed - as supplied by publisher]

Should the dosage of propofol be higher and independent of immunosuppressive therapy in adult cystic fibrosis patients undergoing sedation during flexible video bronchoscopy?

Eur Rev Med Pharmacol Sci. 2020 Nov;24(22):11900-11908

Authors: Brajer-Luftmann B, Stelmach-Mardas M, Mardas M, Grabicki M, Batura-Gabryel H, Piorunek T

Abstract
OBJECTIVE: Flexible video bronchoscopy (FVB) performed under sedation is a useful procedure in adults with cystic fibrosis (CF). Propofol dosage for CF is poorly described, although it is of high importance for professionals. The study aimed to assess whether propofol dosage should be higher in adults CF undergoing sedation during FVB.
PATIENTS AND METHODS: 50 adult CF and non-CF patients undergoing sedation during FVB were included. Clinical features of studied patients were assessed. In CF group spirometry, liver enzymes, inflammatory biomarkers, albumin, protein concentration, WBC were estimated. Propofol and fentanyl dosage was calculated. Multiple regression model was performed.
RESULTS: CF patients were characterized by a lower mean value of body weight and lower mean requirement of total propofol (135 mg in CF vs. 145 mg in non-CF). Calculated propofol dose per kg of body weight was significantly higher in CF (2.43 mg/kg vs. 2.04 mg/kg) and did not depend on the bronchopulmonary disease stage. Propofol dose per kg of body weight was predicted by CF status (CF vs. non-CF), sex, and age.
CONCLUSIONS: Adult CF patients not receiving immunosuppressive therapy require higher propofol dose per kg of body weight compared to non-CF, independently on bronchopulmonary disease stage showing a narrow therapeutic window for propofol in CF group.

PMID: 33275261 [PubMed - as supplied by publisher]

Lung Function Assessment by Impulse Oscillometry in Adults.

Ther Clin Risk Manag. 2020;16:1139-1150

Authors: Porojan-Suppini N, Fira-Mladinescu O, Marc M, Tudorache E, Oancea C

Abstract
Over the past decades, impulse oscillometry (IOS) has gained ground in the battery of pulmonary function tests. Performing the test requires minimal cooperation of the patient; therefore, it is a useful tool, especially in evaluating lung mechanics in children, elderly patients, and those who cannot perform spirometry. Oscillometry has also been used in both clinical and research departments. Studies were published mainly in asthma regarding detection of bronchodilator response and the therapeutic response to different drugs. Furthermore, it has been shown to be a sensitive technique to evaluate disease control. Other studied diseases were COPD, interstitial lung diseases, small airway disease, impairment of lung function due to exposure to occupational hazards or smoking, central airways obstruction, cystic fibrosis, monitoring lung mechanics during mechanical ventilation and sleep, neuromuscular diseases, lung transplant, and graft function. The aim of this review is to present the utility of oscillometry on the previously mentioned clinical fields.

PMID: 33273817 [PubMed]

Heme protects Pseudomonas aeruginosa and Staphylococcus aureus from calprotectin-induced iron starvation.

J Biol Chem. 2020 Dec 03;:

Authors: Zygiel EM, Obisesan AO, Nelson CE, Oglesby AG, Nolan EM

Abstract
Pseudomonas aeruginosa and Staphylococcus aureus are opportunistic bacterial pathogens that cause severe infections in immunocompromised individuals and cystic fibrosis (CF) patients. Both P. aeruginosa and S. aureus require iron to infect the mammalian host. To obtain iron, these pathogens may rely on siderophore mediated ferric [Fe(III)] iron uptake, ferrous [Fe(II)] iron uptake, or heme uptake at different points during infection. The preferred iron source depends on environmental conditions, including the presence of iron-sequestering host defense proteins. Here, we investigate how the presence of heme, a highly relevant iron source during infection, affects bacterial responses to iron withholding by the innate immune protein calprotectin (CP). Prior work has shown that P. aeruginosa is starved of iron in the presence of CP. We report that P. aeruginosa upregulates expression of heme uptake machinery in response to CP. Furthermore, we show that heme protects P. aeruginosa from CP-mediated inhibition of iron uptake and induction of iron starvation responses. We extend our study to a second bacterial pathogen, S. aureus, and demonstrate that CP also inhibits iron uptake and induces iron starvation responses by this pathogen. Similarly to P. aeruginosa, we show that heme protects S. aureus from CP-mediated inhibition of iron uptake and iron starvation responses. These findings expand our understanding of microbial responses to iron sequestration by CP and highlight the importance of heme utilization for bacterial adaptation to host iron withholding strategies.

PMID: 33273016 [PubMed - as supplied by publisher]

Therapeutic effect of nebulized hypertonic saline for muco-obstructive lung diseases: a systematic review and meta-analysis with trial sequential analysis.

J Investig Med. 2020 Dec 03;:

Authors: Zhang Y, Song A, Liu J, Dai J, Lin J

Abstract
Overproduction of mucus and impaired clearance play important roles in the pathogenesis of muco-obstructive lung diseases (MOLDs). This study aims to evaluate the therapeutic effect and safety of nebulized hypertonic saline (HS) on MOLDs. Five electronic databases including PubMed, Excerpt Medica Database (EMBASE), Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and International Standard Randomized Controlled Trial Number Register were searched until June 2019. Randomized controlled trials or randomized controlled crossover trials which investigated the therapeutic effect of HS versus non-HS for MOLDs were included. Twenty-one studies met the eligibility criteria. For cystic fibrosis (CF), although the forced expiratory volume in the first second and forced vital capacity did not improve significantly (mean difference (MD) -0.48, 95% CI -3.72 to 2.76), (MD 1.85, 95% CI -4.31 to 8.01), respectively), the clearance capability of lung and quality of life (QOL) improved significantly in the HS group ((standard mean difference 0.44, 95% CI 0.02 to 0.87), (MD -0.64, 95% CI -)1.14, to 0.13), respectively). However, the results of trial sequential analysis showed the evidence needed more researches to support. The effect of nebulized HS on non-CF bronchiectasis, chronic obstructive pulmonary disease, and primary ciliary dyskinesia also need more evidence to conclude, since current studies are limited and results are inconsistent. Most adverse events of nebulized HS were mild and transient. In summary, the current available evidence suggests that nebulized HS may increase the QOL in CF, but there was no significant improvement in lung function. However, it is not possible to draw firm conclusions for other MOLDs due to limited data.

PMID: 33272932 [PubMed - as supplied by publisher]

Novel Antioxidant Therapy with the Immediate Precursor to Glutathione, γ-Glutamylcysteine (GGC), Ameliorates LPS-Induced Cellular Stress in In Vitro 3D-Differentiated Airway Model from Primary Cystic Fibrosis Human Bronchial Cells.

Antioxidants (Basel). 2020 Nov 30;9(12):

Authors: Hewson CK, Capraro A, Wong SL, Pandzic E, Zhong L, Fernando BSM, Awatade NT, Hart-Smith G, Whan RM, Thomas SR, Jaffe A, Bridge WJ, Waters SA

Abstract
Systemic glutathione deficiency, inflammation, and oxidative stress are hallmarks of cystic fibrosis (CF), an inherited disease that causes persistent lung infections and severe damage to the respiratory system and many of the body organs. Improvements to current antioxidant therapeutic strategies are needed. The dietary supplement, γ-glutamylcysteine (GGC), which is the immediate precursor to glutathione, rapidly boosts cellular glutathione levels following a single dose in healthy individuals. Efficacy of GGC against oxidative stress induced by Pseudomonas aeruginosa, which is a common and chronic pathogen infecting lungs of CF patients, remains unassessed. Primary mucocilliary differentiated airway (bronchial and/or nasal) epithelial cells were created from four individuals with CF. Airway oxidative stress and inflammation was induced by P. aeruginosa lipopolysaccharide (LPS). Parameters including global proteomics alterations, cell redox state (glutathione, oxidative stress), pro-inflammatory mediators (IL-8, IDO-1), and cellular health (membrane integrity, stress granule formation, cell metabolic viability) were assayed under six experimental conditions: (1) Mock, (2) LPS-challenged (3) therapeutic, (4) prophylactic (5) therapeutic and prophylactic and (6) GGC alone. Proteomic analysis identified perturbation of several pathways related to cellular respiration and stress responses upon LPS challenge. Most of these were resolved when cells were treated with GGC. While GGC did not resolve LPS-induced IL-8 and IDO-1 activity, it effectively attenuated LPS-induced oxidative stress and stress granule formation, while significantly increasing total intracellular glutathione levels, metabolic viability and improving epithelial cell barrier integrity. Both therapeutic and prophylactic treatments were successful. Together, these findings indicate that GGC has therapeutic potential for treatment and prevention of oxidative stress-related damage to airways in cystic fibrosis.

PMID: 33266084 [PubMed]

Why is mock care not a good proxy for predicting hand contamination during patient care?

J Hosp Infect. 2020 Nov 30;:

Authors: King MF, Wilson AM, López-García M, Proctor J, Peckham DG, Clifton IJ, Dancer SJ, Noakes CJ

Abstract
BACKGROUND: Healthcare worker behaviours, such as the sequence of their contacts with surfaces and hand hygiene moments are important for understanding disease transmission.
AIM: The study objective was to propose a method for recording sequences of HCW behaviours during mock vs. actual procedures and to evaluate differences for use in infection risk modelling and staff training.
METHODS: Procedures for three types of care were observed under mock and actual settings: IV-drip care, observational care, and doctors' rounds on a respiratory ward in a university teaching hospital. Contacts and hand hygiene behaviours were recorded in real-time using either a handheld tablet or video cameras.
FINDINGS: Actual patient care demonstrated 70% more surface contacts. It was also 2.4 minutes longer but equal in terms of patient contacts. On average, doctors spent 7.5mins (2.5mins for mock) with patients whilst auxiliary nurses took 4.9mins for "obs" (2.4mins for mock). While registered nurses took 3.2mins for mock IV-care and 3.8mins for actual observation this translated to a 44% increase in contacts. In 51% of actual care and 37% of mock care episodes, hand hygiene was performed before patient contact; in comparison, 15% of staff delivering actual care performed hand hygiene after patient contact on leaving the room vs 22% for mock care. Number of overall touches in the patient room was a modest predictor of hand hygiene. Using a model to predict contamination on hands from surface contacts for Staphylococcus aureus, Escherichia coli and norovirus, mock care underestimated microorganisms on hands by about 30%.

PMID: 33271214 [PubMed - as supplied by publisher]

Modelling experimentally measured of ciprofloxacin antibiotic diffusion in Pseudomonas aeruginosa biofilm formed in artificial sputum medium.

PLoS One. 2020;15(12):e0243003

Authors: Kosztołowicz T, Metzler R, Wa Sik S, Arabski M

Abstract
We study the experimentally measured ciprofloxacin antibiotic diffusion through a gel-like artificial sputum medium (ASM) mimicking physiological conditions typical for a cystic fibrosis layer, in which regions occupied by Pseudomonas aeruginosa bacteria are present. To quantify the antibiotic diffusion dynamics we employ a phenomenological model using a subdiffusion-absorption equation with a fractional time derivative. This effective equation describes molecular diffusion in a medium structured akin Thompson's plumpudding model; here the 'pudding' background represents the ASM and the 'plums' represent the bacterial biofilm. The pudding is a subdiffusion barrier for antibiotic molecules that can affect bacteria found in plums. For the experimental study we use an interferometric method to determine the time evolution of the amount of antibiotic that has diffused through the biofilm. The theoretical model shows that this function is qualitatively different depending on whether or not absorption of the antibiotic in the biofilm occurs. We show that the process can be divided into three successive stages: (1) only antibiotic subdiffusion with constant biofilm parameters, (2) subdiffusion and absorption of antibiotic molecules with variable biofilm transport parameters, (3) subdiffusion and absorption in the medium but the biofilm parameters are constant again. Stage 2 is interpreted as the appearance of an intensive defence build-up of bacteria against the action of the antibiotic, and in the stage 3 it is likely that the bacteria have been inactivated. Times at which stages change are determined from the experimentally obtained temporal evolution of the amount of antibiotic that has diffused through the ASM with bacteria. Our analysis shows good agreement between experimental and theoretical results and is consistent with the biologically expected biofilm response. We show that an experimental method to study the temporal evolution of the amount of a substance that has diffused through a biofilm is useful in studying the processes occurring in a biofilm. We also show that the complicated biological process of antibiotic diffusion in a biofilm can be described by a fractional subdiffusion-absorption equation with subdiffusion and absorption parameters that change over time.

PMID: 33270697 [PubMed - as supplied by publisher]

Impaired renal HCO3 - secretion in CFTR deficient mice causes metabolic alkalosis during chronic base-loading.

Acta Physiol (Oxf). 2020 Dec 03;:e13591

Authors: Berg P, Svendsen SL, Hoang TTL, Praetorius HA, Sorensen MV, Leipziger J

Abstract
AIM: Cystic fibrosis patients have an increased risk of developing metabolic alkalosis presumably as a result of altered renal HCO3 - handling. In this study, we directly assess the kidneys' ability to compensate for a chronic base-load in the absence of functional CFTR.
METHODS: Comprehensive urine and blood acid-base analyses were done in anesthetized WT mice or mice lacking either CFTR or pendrin, with or without 7 days of oral NaHCO3 loading. The in vivo experiments were complemented by a combination of immunoblotting and experiments with perfused isolated mouse cortical collecting ducts (CCD).
RESULTS: Base-loaded WT mice maintained acid-base homeostasis by elevating urinary pH and HCO3 - excretion and decreasing urinary net acid excretion. In contrast, pendrin KO mice and CFTR KO mice were unable to increase urinary pH and HCO3 - excretion and unable to decrease urinary net acid excretion sufficiently and thus developed metabolic alkalosis in response to the same base-load. The expression of pendrin was increased in response to the base-load in WT mice with a paralleled increased pendrin function in the perfused CCD. In CFTR KO mice, 7 days of base-loading did not upregulate pendrin expression and apical Cl- /HCO3 - exchange function was strongly blunted in the CCD.
CONCLUSION: CFTR KO mice develop metabolic alkalosis during a chronic base-load because they are unable to sufficiently elevate renal HCO3 - excretion. This can be explained by markedly reduced pendrin function in the absence of CFTR.

PMID: 33270356 [PubMed - as supplied by publisher]

Topographic heterogeneity of lung microbiota in end-stage idiopathic pulmonary fibrosis: the Microbiome in Lung Explants-2 (MiLEs-2) study.

Thorax. 2020 Dec 02;:

Authors: Valenzi E, Yang H, Sembrat JC, Yang L, Winters S, Nettles R, Kass DJ, Qin S, Wang X, Myerburg MM, Methé B, Fitch A, Alder JK, Benos PV, McVerry BJ, Rojas M, Morris A, Kitsios GD

Abstract
BACKGROUND: Lung microbiota profiles in patients with early idiopathic pulmonary fibrosis (IPF) have been associated with disease progression; however, the topographic heterogeneity of lung microbiota and their roles in advanced IPF are unknown.
METHODS: We performed a retrospective, case-control study of explanted lung tissue obtained at the time of lung transplantation or rapid autopsy from patients with IPF and other chronic lung diseases (connective tissue disease-associated interstitial lung disease (CTD-ILD), cystic fibrosis (CF), COPD and donor lungs unsuitable for transplant from Center for Organ Recovery and Education (CORE)). We sampled subpleural tissue and airway-based specimens (bronchial washings and airway tissue) and quantified bacterial load and profiled communities by amplification and sequencing of the 16S rRNA gene.
FINDINGS: Explants from 62 patients with IPF, 15 patients with CTD-ILD, 20 patients with CF, 20 patients with COPD and 20 CORE patients were included. Airway-based samples had higher bacterial load compared with distal parenchymal tissue. IPF basilar tissue had much lower bacterial load compared with CF and CORE lungs (p<0.001). No microbial community differences were found between parenchymal tissue samples from different IPF lobes. Dirichlet multinomial models revealed an IPF cluster (29%) with distinct composition, high bacterial load and low alpha diversity, exhibiting higher odds for acute exacerbation or death.
INTERPRETATION: IPF explants had low biomass in the distal parenchyma of all three lobes with higher bacterial load in the airways. The discovery of a distinct subgroup of patients with IPF with higher bacterial load and worse clinical outcomes supports investigation of personalised medicine approaches for microbiome-targeted interventions.

PMID: 33268457 [PubMed - as supplied by publisher]