Free-breathing MRI for Monitoring Ventilation Changes following Antibiotic Treatment of Pulmonary Exacerbations in Pediatric Cystic Fibrosis.

Eur Respir J. 2020 Dec 10;:

Authors: Munidasa S, Couch MJ, Rayment JH, Voskrebenzev A, Seethamraju R, Vogel-Claussen J, Ratjen F, Santyr G

PMID: 33303537 [PubMed - as supplied by publisher]

Rescue of multiple class II CFTR mutations by elexacaftor+ tezacaftor+ivacaftor mediated in part by the dual activities of Elexacaftor as both corrector and potentiator.

Eur Respir J. 2020 Dec 10;:

Authors: Laselva O, Bartlett C, Gunawardena TNA, Ouyang H, Eckford PDW, Moraes TJ, Bear CE, Gonska T

Abstract
Positive results in preclinical studies of the triple combination of elexacaftor, tezacaftor and ivacaftor, performed in airway epithelial cell cultures obtained from patients harboring F508del-CFTR, translated to impressive clinical outcomes for subjects carrying this mutation in clinical trials and approval of TRIKAFTATM Encouraged by this correlation, we were prompted to evaluate the effect of the elexacaftor, tezacaftor and ivacaftor triple combination on primary nasal epithelial cultures obtained from individuals with rare Class II cystic fibrosis causing mutations; G85E, M1101K and N1303K for which TRIKAFTATM is not approved. Cultures from individuals homozygous for M1101K responded better than cultures harboring G85E and N1303K after treatment with the triple combination with respect to improvement in regulated channel function and protein processing. A similar genotype specific effect of the triple combination was observed when the different mutations were expressed in HEK-293 cells, supporting the hypothesis that these modulators may act directly on the mutant proteins. Detailed studies in nasal cultures and HEK-293 cells showed that the corrector: elexacaftor, exhibited dual activity as both corrector and potentiator and suggested that the potentiator activity contributes to its pharmacological activity. These preclinical studies using nasal epithelial cultures identified mutation genotypes for which elexacaftor, tezacaftor and ivacaftor may produce clinical responses that are comparable to, or inferior to those observed for F508del-CFTR.

PMID: 33303536 [PubMed - as supplied by publisher]

Targeting Cystic Fibrosis Inflammation in the Age of CFTR Modulators: Focus on Macrophages.

Eur Respir J. 2020 Dec 10;:

Authors: Gillan JL, Davidson DJ, Gray RD

Abstract
Cystic fibrosis is a life-shortening, multiorgan, autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The most prominent clinical manifestation in CF is the development of progressive lung disease characterised by an intense, chronic inflammatory airway response that culminates in respiratory failure, and ultimately death. In recent years, a new class of therapeutics which have the potential to correct the underlying defect in CF, known as CFTR modulators, have revolutionised the field. Despite the exciting success of these drugs, their impact on airway inflammation, and its long-term consequences, remain undetermined. In addition, studies querying the absolute requirement for infection as a driver of CF inflammation have challenged the traditional consensus on CF pathogenesis, and also emphasise the need to prioritise complementary anti-inflammatory treatments in CF. Macrophages, often overlooked in CF research despite their integral role in other chronic inflammatory pathologies, have increasingly become recognised as key players in the initiation, perpetuation, and resolution of CF lung inflammation, perhaps as a direct result of CFTR dysfunction. These findings suggest that macrophages may be an important target for novel anti-inflammatory interventional strategies to effectively treat CF lung function decline. This review will consider evidence for the efficacy for anti-inflammatories in the treatment of CF, the potential role of macrophages, and the significance of targeting these pathways at a time when rectifying the basic defect in CF, through use of novel CFTR modulator therapies, is becoming increasingly viable.

PMID: 33303535 [PubMed - as supplied by publisher]

Organoids for personalized treatment of Cystic Fibrosis: Professional perspectives on the ethics and governance of organoid biobanking.

J Cyst Fibros. 2020 Dec 07;:

Authors: Lensink MA, Boers SN, Jongsma KR, Carter SE, van der Ent CK, Bredenoord AL

Abstract
BACKGROUND: Organoid technology is emerging rapidly as a valuable tool for precision medicine, particularly in the field of Cystic Fibrosis (CF). However, biobank storage and use of patient-derived organoids raises specific ethical and practical challenges that demand sound governance. We examined the perspectives of professionals affiliated with CF or organoids on the ethical aspects of organoid biobanking for CF precision medicine. By conducting this study parallel to the process of innovation and development of organoid biobanking, its findings are valuable for the design of responsible governance frameworks.
METHODS: To identify relevant themes and attitudes we conducted 21 semi-structured qualitative interviews with professionals in the field of organoid technology, biobanking, or CF research and care.
RESULTS: We identified three key challenges, as well as the suggestions of professionals on how to address them: (1) The challenges associated with commercial involvement, trust, and ownership, (2) Navigating the blurring boundary between research and clinical care, (3) Appropriate approaches to the informed consent procedure.
CONCLUSION: Sound governance of organoid biobanks aimed at precision medicine requires coming to terms with the fact that its stakeholders no longer belong to separate domains. Responsible governance should be aimed at finding a sound, context-sensitive balance between integration of ongoing co-operation and mutual consideration of interests, and maintaining a feasible and sustainable research climate.

PMID: 33303364 [PubMed - as supplied by publisher]

Airway immunometabolites fuel Pseudomonas aeruginosa infection.

Respir Res. 2020 Dec 10;21(1):326

Authors: Riquelme SA, Prince A

Abstract
Pulmonary infections are associated with a brisk inflammatory reaction to bacterial surface components. Lipopolysaccharides (LPS) trigger macrophage activation and release of mitochondrial metabolites that control the intensity of the immune response. Whereas succinate induces oxidative stress (ROS), HIF1α stabilization, glycolysis and IL-1β release, itaconate suppresses inflammation by inhibiting succinate oxidation, glycolytic flux and promoting anti-oxidant Nrf2-HO-1 functions. P. aeruginosa is a major pathogen associated with acute and chronic lung infection. Although both secreted toxins, LPS and proteases are key factors to establish acute P. aeruginosa pneumonia, lack of these components in chronic P. aeruginosa isolates suggest these organisms exploit other mechanisms to adapt and persist in the lung. Upon inhalation, P. aeruginosa strains trigger airway macrophage reprograming and bacterial variants obtained from acutely and chronically infected subjects exhibit metabolic adaptation consistent with succinate and itaconate assimilation; namely, high expression of extracellular polysaccharides (EPS), reduced lptD-LPS function, increased glyoxylate shunt (GS) activity and substantial biofilm production. In this review we discuss recent findings illustrating how P. aeruginosa induces and adapts to macrophage metabolites in the human lung, and that catabolism of succinate and itaconate contribute to their formidable abilities to tolerate oxidative stress, phagocytosis and immune clearance.

PMID: 33302964 [PubMed - in process]

Chronic rhinosinusitis and endoscopic sinus surgery in children admitted for pulmonary exacerbations of cystic fibrosis.

Int J Pediatr Otorhinolaryngol. 2020 Dec 03;140:110548

Authors: Wang C, Johnson R, Horani S, Brown C, Mitchell R, Shah G

Abstract
OBJECTIVE: Non-surgical management of chronic rhinosinusitis (CRS) in children with cystic fibrosis (CF) has been increasing over the last decade. This study examines inpatient children with pulmonary exacerbation of CF who were also diagnosed with CRS and underwent endoscopic sinus surgery (ESS).
STUDY DESIGN: We used the 2003 to 2016 Kids Inpatient Database to perform a cross-sectional analysis of inpatients (ages 0-21 years) diagnosed with CF and CRS in the United States from 2003 to 2016. Demographics and CF-associated comorbidities were recorded and rates of CRS and ESS in children with CF were examined.
RESULTS: 49,110 children were included in the study. A total of 9334 (19%) were diagnosed with CRS. The average age was 13 (SD 5.9) years; the majority were female (56%), and White (67%). The prevalence of CRS increased from 2003 to 2016 (14%-23%, p < 0.001) while the rate of ESS decreased (20%-11%, p < .001). Patients with CRS that underwent ESS more commonly had CF-associated comorbidities including GI manifestations (15%-25%, p < .001) and liver disease (15%-30%, p < .001).
CONCLUSION: The diagnosis of CRS in children with CF hospitalized for pulmonary exacerbation has increased while ESS has decreased in the last decade. Patients with CRS that underwent ESS more commonly had CF-associated comorbidities. Studies to determine whether children with CF-associated comorbidities are more likely to benefit from ESS are needed.

PMID: 33302019 [PubMed - as supplied by publisher]

Trends in the Prevalence of Non-tuberculous Mycobacterial Infection in Patients with Non-Cystic Fibrosis Bronchiectasis in South Korea, 2012-2016.

Chest. 2020 Dec 07;:

Authors: Lee SJ, Choi H, Lee H, Ra SW, Oh YM, Ju S, You JW, Jeong YY, Kim HC, Lee JD

PMID: 33301746 [PubMed - as supplied by publisher]

Growth, Body Composition, and Lung Function in Prepubertal Children with Cystic Fibrosis Diagnosed by Newborn Screening.

Nutr Clin Pract. 2020 Dec 10;:

Authors: Owen E, Williams JE, Davies G, Wallis C, Grant RL, Fewtrell MS

Abstract
BACKGROUND: Children with cystic fibrosis (CF) are at risk of altered body composition (BC). Newborn screening (NBS) may lead to improved BC outcomes. We investigated BC and its relationship with lung function in prepubertal children diagnosed with CF by NBS. Secondary aims explored predictors of fat-free mass (FFM) and lung function.
METHODS: Thirty-seven screened (non-meconium ileus) children with CF (20 boys) born 2007-2012 had a dual-energy x-ray absorptiometry scan at 5-8 years to determine whole-body (WB) and appendicular BC. Anthropometry was performed and routine spirometry recorded. Results were converted to z-scores, height-adjusted (fat mass index [FMI] and FFM index [FFMI]) and compared with population mean values. Predictors of forced expiratory volume in 1 second (FEV1 ) were assessed using linear regression.
RESULTS: Height, body mass index (BMI), and FEV1 were within normal limits, however, weight and BC were significantly low compared with reference data (weight, P = .03; WB FMI, P = .001; WB FFMI, P = .009). Gender differences were detected, with lower appendicular BC in boys and lower weight, BMI, and BC in girls. The association between FEV1 and WB FFMI (r = 0.38; P = .02) was stronger than with BMI (r = 0.29; P = .08). WB FFMI was the only significant predictor of FEV1 in a multivariable model (95% CI, 0.11-0.99; P = .016).
CONCLUSION: In this NBS CF population, gender differences in growth and BC were apparent despite preserved lung function. These results support BC assessment in prepubertal children, particularly girls, with an opportunity to direct interventions to optimize FFM.

PMID: 33301217 [PubMed - as supplied by publisher]

Longitudinal Assessment of Patients With Cystic Fibrosis Lung Disease With Multivolume Noncontrast MRI and Spirometry.

J Magn Reson Imaging. 2020 Dec 10;:

Authors: Pennati F, Borzani I, Moroni L, Russo MC, Faelli N, Aliverti A, Colombo C

Abstract
BACKGROUND: MRI has been suggested as a radiation-free imaging modality to investigate early structural alterations and regional functional impairment in cystic fibrosis (CF) lung disease.
PURPOSE/HYPOTHESIS: To compare functional and morphological MRI changes over the course of the disease to changes in spirometry.
STUDY TYPE: Longitudinal retrospective study.
POPULATION: Twenty patients with CF lung disease (at baseline, age = 16.5 (13.3-20.6) years, forced expiratory volume in 1 second (as % of predicted [%pred]) FEV1 = 71 (59-87) %pred, forced expiratory flow at 25-75% of forced vital capacity FEF25-75 = 39 (25-63) %pred.
FIELD STRENGTH/SEQUENCE: 1.5T / T2 -weighted HASTE; T2 -weighted TSE-PROPELLER; T2 -weighted bSSFP; T1 -weighted 3D GRE.
ASSESSMENT: Nonenhanced chest MRI and spirometry were retrospectively collected over a 3-year period from the initial recruitment visit. Images acquired at end-inspiration and end-expiration were registered by software using the optical flow method to measure expiratory-inspiratory differences in MR signal-intensity (Δ1 H-MRI). Measures of CF functional impairment were defined from Δ1 H-MRI: Δ1 H-MRI median, Δ1 H-MRI quartile coefficient of variation (QCV), and percent low-signal-variation volume (LVV). MR images were also evaluated by three readers using a CF-specific scoring system.
STATISTICAL TESTS: Spearman correlation analysis, Spearman rank correlation analysis, linear mixed-effect model analysis, intraclass correlation coefficient.
RESULTS: Functional imaging parameters and total morphological score correlated with all spirometric measures, as did subscores of bronchial wall thickening/bronchiectasis, mucus plugging, and consolidation. Overall, the percent change of Δ1H-MRI median correlated with the percent change of FEV1 (ΔFEV1 , r = 0.41, P < 0.01) and the percent change of FEF25-75 (ΔFEF25-75%, r = 0.38, P < 0.01). The percent change of LVV correlated with ΔFEV1 (r = -0.47, P < 0.001) and ΔFEF25-75 (r = -0.50, P < 0.001).
DATA CONCLUSION: These preliminary results suggest that nonenhanced multivolume MRI may provide a feasible tool to regionally map early pulmonary alterations for longitudinal evaluation of CF lung disease, without exposing the patients to ionizing radiation.
LEVEL OF EVIDENCE: 3T TECHNICAL EFFICACY STAGE: 5.

PMID: 33300639 [PubMed - as supplied by publisher]

Cystic Fibrosis F508del Carriers and Cancer Risk: Results from the UK Biobank.

Int J Cancer. 2020 Dec 10;:

Authors: Shi Z, Wei J, Na R, Resurreccion WK, Zheng SL, Hulick PJ, Helfand BT, Talamonti MS, Xu J

Abstract
Cystic fibrosis (CF) carriers carrying one defective copy of a CFTR germline mutation are common in the general population. A recent study reported associations of CF carriers with risk for cancers of digestive organs and pancreatic cancer. In the current study, we assessed associations of CFTR F508del carriers with the risk for 54 types of cancers in the UK Biobank, a large population-based study. In Caucasians, compared to the carrier rate of 3.15% (12,357/392,274) in non-cancer subjects, the rate was significantly higher in cancer patients overall (2,621/79,619=3.29%), especially in patients with colorectal cancer (247/6,667=3.70%), cancers of gallbladder and biliary tract (21/351=5.98%), thyroid cancer (30/665=4.51%), and unspecified non-Hodgkin's lymphoma (74/1,805=4.10%), all P<=0.05. In contrast, the carrier rate in patients with cancers of lung and bronchus was significantly lower (89/3,463=2.57%), P=0.05. The association of CFTR F508del carriers with these types of cancer remained significant after adjusting for respective cancer-specific risk factors. For pancreatic cancer, although a higher carrier rate (38/1,004=3.78%) was found in patients with this cancer, the difference was not statistically significant (P=0.26). This null association was unlikely due to lack of statistical power; the large sample size of our study had >80% power, at a significance level of 0.05, to detect an association of >1.5-fold increased risk. In conclusion, the identified associations of CFTR F508del carriers with multiple types of cancer may have potential biological and clinical implications if confirmed in independent study populations. This article is protected by copyright. All rights reserved.

PMID: 33300603 [PubMed - as supplied by publisher]

Lung transplant referrals for individuals with cystic fibrosis: a pediatric perspective on the Cystic Fibrosis Foundation consensus guidelines.

Pediatr Pulmonol. 2020 Dec 10;:

Authors: Solomon M, Mallory GB

Abstract
Lung transplant referral guidelines for individuals with cystic fibrosis (CF) were published recently. Most of the recommendations focus on the specific indications and barriers to transplantation in adults with CF. Although the number of children with CF and end-stage lung disease continues to decrease, the specific issues related to pediatric patients merit further elucidation. We address each recommendation from the recent publication with a pediatric perspective. Furthermore, we note some significant differences between the practice and policy related to lung transplantation between Canada and the United States. This article is protected by copyright. All rights reserved.

PMID: 33300243 [PubMed - as supplied by publisher]

Phages as immunomodulators and their promising use as anti-inflammatory agents in a cftr loss-of-function zebrafish model.

J Cyst Fibros. 2020 Dec 06;:

Authors: Cafora M, Brix A, Forti F, Loberto N, Aureli M, Briani F, Pistocchi A

Abstract
Cystic Fibrosis (CF), one of the most frequent hereditary diseases due to mutations in the CFTR gene, causes mortality in humans mainly due to infection in the respiratory system. However, besides the massive inflammatory response triggered by chronic bacterial infections, a constitutive pro-inflammatory state associated with the most common CFTR mutations has been reported in paediatric cases before the onset of bacterial colonization. In previous works we isolated and characterized a mix of virulent bacteriophages (phage cocktail) able to efficiently counteract Pseudomonas aeruginosa infection in a zebrafish model with cftr loss-of-function (LOF), but also showing anti-inflammatory effects in zebrafish embryos not infected by bacteria. On these premises, in this work we demonstrated the anti-inflammatory role of the phage cocktail both in the wild-type (WT) and hyper-inflamed cftr LOF zebrafish embryos in terms of reduction of pro-inflammatory markers. We also dissect that only the virion proteinaceous components, but not the phage DNA, are responsible for the immune-modulatory effect and that this action is elicited through the activation of the Toll-like Receptor (TLR) pathway. In the cftr LOF zebrafish embryos, we demonstrated that phages injection significantly reduces neutrophil migration following acute inflammatory induction. The elucidation of the molecular interaction between phages and the cells of vertebrate immune system might open new possibility in their manipulation for therapeutic benefits especially in diseases such as cystic fibrosis, characterized by chronic infection and inflammation.

PMID: 33298374 [PubMed - as supplied by publisher]

Comparative evaluation of the effect of different growth media on in vitro sensitivity to azithromycin in multi-drug resistant Pseudomonas aeruginosa isolated from cystic fibrosis patients.

Antimicrob Resist Infect Control. 2020 Dec 09;9(1):197

Authors: Sörensen M, Khakimov B, Nurjadi D, Boutin S, Yi B, Dalpke AH, Eigenbrod T

Abstract
Long-term treatment with azithromycin is a therapeutic option in Cystic Fibrosis (CF) patients chronically infected with P. aeruginosa. It was recently shown that azithromycin has direct antimicrobial activity when P. aeruginosa isolates are tested in Roswell Park Memorial Institute medium supplemented with fetal calf serum (RPMI 1640/FCS) by broth microdilution. We now investigated whether (i) azithromycin might also be active against multidrug resistant (MDR) P. aeruginosa isolated from CF patients and (ii) how in vitro sensitivity assays perform in synthetic cystic fibrosis sputum medium (SCFM), a medium that mimics the particular CF airway environment. In 17 (59%) out of 29 MDR P. aeruginosa CF isolates MICs for azithromycin ranged between 0.25 and 8 μg/ml and 12 isolates (41%) showed a MIC ≥512 μg/ml when measured in RPMI/FCS. In contrast, MICs were ≥ 256 μg/ml for all P. aeruginosa MDR isolates when tested in either SCFM or in conventional cation-adjusted Mueller Hinton Broth. High MIC values observed in CF adapted medium SCFM for both PAO1 and MDR P. aeruginosa CF isolates, as opposed to findings in RPMI, argue against routine azithromycin MIC testing of CF isolates.

PMID: 33298147 [PubMed - in process]

Airway Redox Homeostasis and Inflammation Gone Awry: From Molecular Pathogenesis to Emerging Therapeutics in Respiratory Pathology.

Int J Mol Sci. 2020 Dec 07;21(23):

Authors: Checa J, Aran JM

Abstract
As aerobic organisms, we are continuously and throughout our lifetime subjected to an oxidizing atmosphere and, most often, to environmental threats. The lung is the internal organ most highly exposed to this milieu. Therefore, it has evolved to confront both oxidative stress induced by reactive oxygen species (ROS) and a variety of pollutants, pathogens, and allergens that promote inflammation and can harm the airways to different degrees. Indeed, an excess of ROS, generated intrinsically or from external sources, can imprint direct damage to key structural cell components (nucleic acids, sugars, lipids, and proteins) and indirectly perturb ROS-mediated signaling in lung epithelia, impairing its homeostasis. These early events complemented with efficient recognition of pathogen- or damage-associated recognition patterns by the airway resident cells alert the immune system, which mounts an inflammatory response to remove the hazards, including collateral dead cells and cellular debris, in an attempt to return to homeostatic conditions. Thus, any major or chronic dysregulation of the redox balance, the air-liquid interface, or defects in epithelial proteins impairing mucociliary clearance or other defense systems may lead to airway damage. Here, we review our understanding of the key role of oxidative stress and inflammation in respiratory pathology, and extensively report current and future trends in antioxidant and anti-inflammatory treatments focusing on the following major acute and chronic lung diseases: acute lung injury/respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, and cystic fibrosis.

PMID: 33297418 [PubMed - in process]

Monogenic Diabetes in a Child with Cystic Fibrosis: A Case Report and Review of the Literature.

J Endocr Soc. 2021 Jan 01;5(1):bvaa165

Authors: Scully KJ, Sawicki G, Kremen J, Putman MS

Abstract
Cystic fibrosis-related diabetes (CFRD) is associated with worsening pulmonary function, lower body mass index, increased infection frequency, and earlier mortality. While the incidence of CFRD is rising, its development in patients under the age of 10 years is uncommon. We present a 9-year-old girl with cystic fibrosis (CF) who presented with a 5-year history of nonprogressive hyperglycemia, demonstrated by abnormal oral glucose tolerance tests, glycated hemoglobin A1c (HbA1c) levels consistently >6.5%, and negative pancreatic autoantibodies. Subsequent genetic testing revealed a pathogenic heterozygous recessive mutation in the GCK gene at c.667G>A (p.Gly223Ser), consistent with a diagnosis of GCK-MODY. Significant dysglycemia in young children with CF should raise suspicion for alternative etiologies of diabetes and warrants further investigation. The clinical impact of underlying monogenic diabetes in patients with CF is unclear, and close follow-up is warranted. This case also offers unique insight on the impact of hyperglycemia in the absence of insulin deficiency on CF-specific outcomes.

PMID: 33294763 [PubMed]

Comparative transcriptome analysis unveils the adaptative mechanisms of Scedosporium apiospermum to the microenvironment encountered in the lungs of patients with cystic fibrosis.

Comput Struct Biotechnol J. 2020;18:3468-3483

Authors: Vandeputte P, Dugé de Bernonville T, Le Govic Y, Le Gal S, Nevez G, Papon N, Bouchara JP

Abstract
Scedosporium species rank second among the filamentous fungi colonizing the lungs of patients with cystic fibrosis (CF). Apart from the context of immunodeficiency (lung transplantation), the colonization of the CF airways by these fungi usually remains asymptomatic. Why the colonization of the lower airways by Scedosporium species is fairly tolerated by CF patients while these fungi are able to induce a marked inflammatory reaction in other clinical contexts remains questionable. In this regards, we were interested here in exploring the transcriptional reprogramming that accompanies the adaptation of these fungi to the particular microenvironment encountered in the airways of CF patients. Cultivation of Scedosporium apiospermum in conditions mimicking the microenvironment in the CF lungs was shown to induce marked transcriptional changes. This includes notably the down-regulation of enzymes involved in the synthesis of some major components of the plasma membrane which may reflect the ability of the fungus to evade the host immune response by lowering the biosynthesis of some major antigenic determinants or inhibiting their targeting to the cell surface through alterations of the membrane fluidity. In addition, this analysis revealed that some genes encoding enzymes involved in the biosynthesis of some mycotoxins were down-regulated suggesting that, during the colonization process, S. apiospermum reduces the production of some toxic secondary metabolites to prevent exacerbation of the immune system response. Finally, a strong up-regulation of many genes encoding enzymes involved in the degradation of aromatic compounds was observed, suggesting that these catabolic properties would predispose the fungus to particular patterns of human pathogenicity. Together these data provide new insights into the adaptative mechanisms developed by S. apiospermum in the CF lungs, which should be considered for identification of potential targets for drug development, but also for the experimental conditions to be used in in vitro susceptibility testing of clinical isolates to current antifungals.

PMID: 33294141 [PubMed]

Phenotypic and Genomic Comparison of the Two Most Common ExoU-Positive Pseudomonas aeruginosa Clones, PA14 and ST235.

mSystems. 2020 Dec 08;5(6):

Authors: Fischer S, Dethlefsen S, Klockgether J, Tümmler B

Abstract
Genotyping of 2,882 Pseudomonas aeruginosa isolates that had been collected during the last 40 years identified the ExoU-positive lineages PA14 (ST253) and ST235 as the second and third most frequent clones in the P. aeruginosa population. Both clones were approximately 2-fold more frequently detected in animate habitats than in soil or aquatic habitats. While ST253 clone isolates were causing mainly acute and chronic infections in humans, ST235 isolates had been preferentially collected from hospitalized patients with severe acute infections, particularly, keratitis, urinary tract infections, burn wounds, and ventilator-associated pneumonia. The two major exoU clones differed substantially in the composition and flexibility of the accessory genome and by more than 8,000 amino acid sequences. Pronounced sequence variation between orthologs was noted in genes encoding elements of secretion systems and secreted effector molecules, including the type III secretion system, indicating the modes of action of the different clones. When comparing representatives of the two clones in batch culture, the PA14 strain orchestrated the quorum sensing circuitry for the expression of pathogenic traits and stopped growing in batch culture when it entered the stationary phase, but the quorum sensing-deficient ST235 strain expressed high type III secretion activity and continued to grow and to divide. In summary, unrestricted growth, high constitutive type III secretion activity, and facilitated uptake of foreign DNA could be major features that have made ST235 a global high-risk clone associated with poor outcomes of acute nosocomial infections.IMPORTANCE The ubiquitous and metabolically versatile environmental bacterium Pseudomonas aeruginosa can cause infections in a wide variety of hosts, including insects, plants, animals, and humans. P. aeruginosa is one of the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens that are the major cause of nosocomial infections in the United States and are a threat all over the world because of their capacity to become increasingly resistant to all available antibiotics. Most experimental work on P. aeruginosa has been performed with reference strains PAO1 and PA14, providing deep insight into key metabolic and regulatory pathways thought to be applicable to all P. aeruginosa strains. However, this comparative study on the two most common exoU-positive clones taught us that there are major lineages in the population such as the global high-risk clone ST235 that exhibit uncommon traits of lifestyle, genome mobility, and pathogenicity distinct from those in our knowledge gained from the studies with the reference strains.

PMID: 33293405 [PubMed]

New Insights into the Binding Features of F508del CFTR Potentiators: A Molecular Docking, Pharmacophore Mapping and QSAR Analysis Approach.

Pharmaceuticals (Basel). 2020 Dec 04;13(12):

Authors: Righetti G, Casale M, Tonelli M, Liessi N, Fossa P, Pedemonte N, Millo E, Cichero E

Abstract
Cystic fibrosis (CF) is the autosomal recessive disorder most recurrent in Caucasian populations. To combat this disease, many life-prolonging therapies are required and deeply investigated, including the development of the so-called cystic fibrosis transmembrane conductance regulator (CFTR) modulators, such as correctors and potentiators. Combination therapy with the two series of drugs led to the approval of several multi-drug effective treatments, such as Orkambi, and to the recent promising evaluation of the triple-combination Elexacaftor-Tezacaftor-Ivacaftor. This scenario enlightened the effectiveness of the multi-drug approach to pave the way for the discovery of novel therapeutic agents to contrast CF. The recent X-crystallographic data about the human CFTR in complex with the well-known potentiator Ivacaftor (VX-770) opened the possibility to apply a computational study aimed to explore the key features involved in the potentiator binding. Herein, we discussed molecular docking studies performed onto the chemotypes so far discussed in the literature as CFTR potentiator, reporting the most relevant interactions responsible for their mechanism of action, involving Van der Waals interactions and π-π stacking with F236, Y304, F305 and F312, as well as H-bonding F931, Y304, S308 and R933. This kind of positioning will stabilize the effective potentiator at the CFTR channel. These data have been accompanied by pharmacophore analyses, which promoted the design of novel derivatives endowed with a main (hetero)aromatic core connected to proper substituents, featuring H-bonding moieties. A highly predictive quantitative-structure activity relationship (QSAR) model has been developed, giving a cross-validated r2 (r2cv) = 0.74, a non-cross validated r2 (r2ncv) = 0.90, root mean square error (RMSE) = 0.347, and a test set r2 (r2pred) = 0.86. On the whole, the results are expected to gain useful information to guide the further development and optimization of new CFTR potentiators.

PMID: 33291847 [PubMed]

Triage for Malnutrition Risk among Pediatric and Adolescent Outpatients with Cystic Fibrosis, Using a Disease-Specific Tool.

Children (Basel). 2020 Dec 04;7(12):

Authors: Poulimeneas D, Grammatikopoulou MG, Petrocheilou A, Kaditis AG, Vassilakou T

Abstract
Malnutrition prevails in considerable proportions of children with Cystic Fibrosis (CF), and is often associated with adverse outcomes. For this, routine screening for malnutrition is pivotal. In the present cross-sectional study, we aimed to assess the risk for malnutrition in pediatric outpatients with CF. A total of 76 outpatients (44 girls, 11.9 ± 3.9 years old, 39.5% adolescents) were recruited and anthropometric, clinical, dietary and respiratory measures were collected. All outpatients were screened for malnutrition risk with a validated disease-specific instrument. Most children exhibited a low risk for malnutrition (78.9%), whereas none of the participants were characterized as having a high malnutrition risk. In the total sample, malnutrition risk was positively associated with age (r = 0.369, p = 0.001), and inversely related to the body mass index (r = -0.684, p < 0.001), height z-score (r = -0.264, p = 0.021), and forced expiratory volume (FEV1%, r = -0.616, p < 0.001). Those classified as having a low malnutrition risk were younger (p = 0.004), heavier (p < 0.001) and taller (p = 0.009) than their counterparts with a moderate risk. On the other hand, patients in the moderate risk group were more likely pubertal (p = 0.034), with a reduced mid-upper arm fat area (p = 0.011), and worse pulmonary function (p < 0.001). Interestingly, none of the children attaining ideal body weight were classified as having a moderate malnutrition. risk, whereas 37.5% of the patients allocated at the moderate risk group exhibited physiological lung function. In this cohort of outpatients with CF that were predominantly well-nourished and attained physiological lung function, malnutrition risk was identified only in small proportions of the sample. Our data support that patients that are older, pubertal, or have diminished fat mass are at greater risk for malnutrition.

PMID: 33291524 [PubMed]

A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin.

Antibiotics (Basel). 2020 Dec 06;9(12):

Authors: Patel N, Swavey S, Robinson J

Abstract
One of the greatest threats to human health is the rise in antibiotic-resistant bacterial infections. Pseudomonas aeruginosa (PsA) is an "opportunistic" pathogen known to cause life-threatening infections in immunocompromised individuals and is the most common pathogen in adults with cystic fibrosis (CF). We report here a cationic zinc (II) porphyrin, ZnPor, that effectively kills planktonic and biofilm-associated cells of PsA. In standard tests against 16-18 h-old biofilms, concentrations as low as 16 µg/mL resulted in the extensive disruption and detachment of the matrix. The pre-treatment of biofilms for 30 min with ZnPor at minimum inhibitory concentration (MIC) levels (4 µg/mL) substantially enhanced the ability of tobramycin (Tobra) to kill biofilm-associated cells. We demonstrate the rapid uptake and accumulation of ZnPor in planktonic cells even in dedicated heme-uptake system mutants (ΔPhu, ΔHas, and the double mutant). Furthermore, uptake was unaffected by the ionophore carbonyl cyanide m-chlorophenyl hydrazine (CCCP). Cells pre-exposed to ZnPor took up the cell-impermeant dye SYTOXTM Green in a concentration-dependent manner. The accumulation of ZnPor did not result in cell lysis, nor did the cells develop resistance. Taken together, these properties make ZnPor a promising candidate for treating multi-drug-resistant infections, including persistent, antibiotic-resistant biofilms.

PMID: 33291344 [PubMed]