Will airway gene therapy for cystic fibrosis improve lung function? New imaging technologies can help us find out.

Hum Gene Ther. 2020 Jul 27;:

Authors: Parsons D, Donnelley M

Abstract
The promise of genetic therapies has turned into reality in recent years, with new first-line treatments for fatal diseases now available to patients. The development and testing of genetic therapies for respiratory diseases such as cystic fibrosis (CF) has also progressed. The addition of gene editing to the genetic agent toolbox, and its early success in other organ systems, suggests we will see rapid expansion of gene correction options for CF in the future. Although substantial progress has been made in creating techniques and genetic agents that can be highly effective for CF correction in vitro, physiologically-relevant functional in vivo changes have been largely prevented by poor delivery efficiency within the lungs. Somewhat hidden from view however is the absence of reliable, accurate, detailed, and non-invasive outcome measures that can detect subtle disease and treatment effects in the lungs of humans or animal models. The ability to measure the fundamental function of the lung - ventilation, the effective transport of air throughout the lung - has been constrained by the available measurement technologies. Without sensitive measurement methods, it is difficult to quantify the effectiveness of genetic therapies for CF. The mainstays of lung health assessment are spirometry, which cannot provide adequate disease localization and is not sensitive enough to detect small early changes in disease; and computed tomography, which provides structural rather than functional information. Magnetic resonance imaging using hyperpolarized gases is increasingly useful for lung ventilation assessment, and it removes the radiation risk that accompanies X-ray methods. A new lung imaging technique, X-ray Velocimetry can now offer highly detailed regional lung ventilation information well suited to the diagnosis, treatment, and monitoring needs of CF lung disease, particularly after the application of genetic therapies. In this review we discuss the options now available for imaging-based lung function measurement in the generation and use of genetic and other therapies for treating CF lung disease.

PMID: 32718206 [PubMed - as supplied by publisher]

[Bronchiectasis in Turkey: Under the light of national publications].

Tuberk Toraks. 2020 Mar;68(1):48-65

Authors: Bülbül Y, Erçen Diken Ö, Uğur Chousein EG

Abstract
In this review, we aimed to determine the etiopathogenesis, diagnosis and treatment of non-cystic fibrosis bronchiectasis in the light of scientific studies conducted in our country. For this purpose, Pubmed, Web of Science ve Ulakbim TR Dizin were searched and the publications available as of July 2019 were evaluated and the findings of these studies were summarized and presented.

PMID: 32718140 [PubMed - in process]

Cell-Based Therapeutic Approaches for Cystic Fibrosis.

Int J Mol Sci. 2020 Jul 23;21(15):

Authors: Duchesneau P, Waddell TK, Karoubi G

Abstract
Cystic Fibrosis (CF) is a chronic autosomal recessive disease caused by defects in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Cystic Fibrosis affects multiple organs but progressive remodeling of the airways, mucus accumulation, and chronic inflammation in the lung, result in lung disease as the major cause of morbidity and mortality. While advances in management of CF symptoms have increased the life expectancy of this devastating disease, and there is tremendous excitement about the potential of new agents targeting the CFTR molecule itself, there is still no curative treatment. With the recent advances in the identification of endogenous airway progenitor cells and in directed differentiation of pluripotent cell sources, cell-based therapeutic approaches for CF have become a plausible treatment method with the potential to ultimately cure the disease. In this review, we highlight the current state of cell therapy in the CF field focusing on the relevant autologous and allogeneic cell populations under investigation and the challenges associated with their use. In addition, we present advances in induced pluripotent stem (iPS) cell approaches and emerging new genetic engineering methods, which have the capacity to overcome the current limitations hindering cell therapy approaches.

PMID: 32718005 [PubMed - in process]

Imaging and the Lung Transplant Patient.

Radiol Technol. 2019 Sep;91(1):27-47

Authors: Flanagan JC

Abstract
Lung transplantation can prolong and improve quality of life for patients affected by end-stage lung disease. Potential lung transplant patients undergo a rigorous preoperative assessment that includes multiple medical imaging studies. These studies provide information that help physicians determine whether the patient is a surgical candidate, as well as the surgical technique that should be used during transplantation. Imaging studies also are used in long-term care to detect complications in patients after lung transplantation.

PMID: 31471476 [PubMed - indexed for MEDLINE]

24 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

"Cystic Fibrosis"

These pubmed results were generated on 2020/07/28

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

18 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results:

"Cystic Fibrosis"

These pubmed results were generated on 2020/07/28

PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Promoting Emotional Wellness in Children with CF, Part II: Mental Health Assessment and Intervention.

Pediatr Pulmonol. 2020 Jul 24;:

Authors: Georgiopoulos AM, Christon LM, Filigno SS, Mueller A, Prieur MG, Boat TF, Smith BA

Abstract
This is the second of two companion papers which examine emotional wellness of children with cystic fibrosis (CF) during the early years of life, defined here as the period between birth to age 12. Both papers promote optimal mental health and well-being, with an emphasis on early identification and intervention. The first paper explores child and family resilience. Here, we discuss strategies for pediatric CF teams to provide routine, systematic mental health assessment, anticipatory guidance, brief intervention, and triage to evidence-based treatment when needed, while addressing barriers to accessing care. Many mental health conditions emerge before the age of 12, with the potential for lifelong effects on individuals, their family, and society. Living with a chronic illness such as CF can further increase the risk of mental health concerns and, in a bidirectional manner, their consequences for quality of life, sustaining daily care, and health outcomes. There has been a significant focus in recent years on the mental health and wellness of adolescents and adults with CF, but less attention to specifics of depression and anxiety in younger children, or to other common pediatric comorbidities including trauma, developmental disorders such as Attention-Deficit/Hyperactivity Disorder (ADHD) or Autism Spectrum Disorder (ASD), and oppositional behavior. Given the availability of psychometrically sound screening instruments and effective interventions, routinely addressing the mental health of children with CF and their families is feasible to integrate within multidisciplinary CF care, allowing for a personalized approach respecting individual needs, values, and goals. This article is protected by copyright. All rights reserved.

PMID: 32706527 [PubMed - as supplied by publisher]

Sulfhemoglobinemia associated with meconium ileus in cystic fibrosis.

Pediatr Pulmonol. 2020 Jul 24;:

Authors: Christensen C, Sivapatham G, McKinney ML, Stammers D

PMID: 32706503 [PubMed - as supplied by publisher]

Picornavirus Cellular Remodeling: Doubling Down in Response to Viral-Induced Inflammation.

Curr Clin Microbiol Rep. 2020 Jun;7(2):31-37

Authors: Bouin A, Semler BL

Abstract
Purpose of Review: To highlight recent findings on how picornavirus infections of the airways and cardiac tissues impact cellular inflammation and remodeling events.
Recent Findings: Recent published work has revealed that although many picornavirus infections appear to be initially asymptomatic, there are significant disease sequelae that result from chronic or persistent infections and the long-term, pathogenic effects on host tissues.
Summary: Because many acute picornavirus infections are asymptomatic, it is difficult to diagnose these pathologies at the early stages of disease. As a result, we must rely on preventative measures (i.e., vaccination) or discover novel treatments to reverse tissue damage and remodeling in affected individuals. Both of these strategies will require a comprehensive knowledge of virus-and cell-specific replication determinants and how these processes induce pathogenic effects in infected cells and tissues.

PMID: 32704466 [PubMed]

Impaired Renal HCO3 - Excretion in Cystic Fibrosis.

J Am Soc Nephrol. 2020 Jul 23;:

Authors: Berg P, Svendsen SL, Sorensen MV, Larsen CK, Andersen JF, Jensen-Fangel S, Jeppesen M, Schreiber R, Cabrita I, Kunzelmann K, Leipziger J

Abstract
BACKGROUND: Patients with cystic fibrosis (CF) do not respond with increased urinary HCO3 - excretion after stimulation with secretin and often present with metabolic alkalosis.
METHODS: By combining RT-PCR, immunohistochemistry, isolated tubule perfusion, in vitro cell studies, and in vivo studies in different mouse models, we elucidated the mechanism of secretin-induced urinary HCO3 - excretion. For CF patients and CF mice, we developed a HCO3 - drinking test to assess the role of the cystic fibrosis transmembrane conductance regulator (CFTR) in urinary HCO3 -excretion and applied it in the patients before and after treatment with the novel CFTR modulator drug, lumacaftor-ivacaftor.
RESULTS: β-Intercalated cells express basolateral secretin receptors and apical CFTR and pendrin. In vivo application of secretin induced a marked urinary alkalization, an effect absent in mice lacking pendrin or CFTR. In perfused cortical collecting ducts, secretin stimulated pendrin-dependent Cl-/HCO3 - exchange. In collecting ducts in CFTR knockout mice, baseline pendrin activity was significantly lower and not responsive to secretin. Notably, patients with CF (F508del/F508del) and CF mice showed a greatly attenuated or absent urinary HCO3 --excreting ability. In patients, treatment with the CFTR modulator drug lumacaftor-ivacaftor increased the renal ability to excrete HCO3 -.
CONCLUSIONS: These results define the mechanism of secretin-induced urinary HCO3 - excretion, explain metabolic alkalosis in patients with CF, and suggest feasibility of an in vivo human CF urine test to validate drug efficacy.

PMID: 32703846 [PubMed - as supplied by publisher]

Comparative analysis of phenotypic and genotypic antibiotic susceptibility patterns in Mycobacterium avium complex.

Int J Infect Dis. 2020 Apr;93:320-328

Authors: Wetzstein N, Kohl TA, Andres S, Schultze TG, Geil A, Kim E, Biciusca T, Hügel C, Hogardt M, Lehn A, Vehreschild MJGT, Wolf T, Niemann S, Maurer FP, Wichelhaus TA

Abstract
OBJECTIVE: Phenotypic (Sensititre Myco, pDST) and genotypic drug susceptibility testing (GenoType NTM DR, gDST) in M. avium complex (MAC) have become available as standardized assays, but comparable data is needed. This study aimed to investigate the phenotypic and genotypic drug susceptibility patterns in MAC clinical isolates.
METHODS: Overall, 98 isolates from 85 patients were included. pDST and gDST were performed on all isolates and results compared regarding specificity and sensitivity using pDST as a reference method. The impact of drug instability on pDST results was studied using a biological assay over 14 days. In addition, the evolution of antimicrobial resistance was investigated in sequential isolates of 13 patients.
RESULTS: Macrolide resistance was rare, 1.2% (95% CI 0.7-7.3) of isolates in the base cohort. No aminoglycoside resistances were found, but 14.1% of the studied isolates (95% CI 7.8-23.8) showed intermediate susceptibility. The GenoType NTM DR identified two out of four macrolide-resistant isolates. Antibiotic stability was demonstrated to be poor in rifampicin, rifabutin, and doxycycylin.
CONCLUSIONS: pDST results in NTM for unstable antibiotics must be interpreted with care. A combination of pDST and gDST will be useful for the guidance of antimicrobial therapy in MAC-disease.

PMID: 32147539 [PubMed - indexed for MEDLINE]

Lubiprostone protects esophageal mucosa from acid injury in porcine esophagus.

Am J Physiol Gastrointest Liver Physiol. 2020 04 01;318(4):G613-G623

Authors: Krüger L, Pridgen TA, Taylor ER, Garman KS, Blikslager AT

Abstract
Esophageal injury from acid exposure related to gastroesophageal reflux disease is a common problem and a risk factor for development of Barrett's esophagus and esophageal adenocarcinoma. Our previous work highlights the benefits of using porcine esophagus to study human esophageal disease because of the similarities between porcine and human esophagus. In particular, esophageal submucosal glands (ESMGs) are present in human esophagus and proximal porcine esophagus but not in rodent esophagus. Although CFTR is expressed in the ducts of ESMGs, very little is known about CFTR and alternate anion channels, including ClC-2, in the setting of acid-related esophageal injury. After finding evidence of CFTR and ClC-2 in the basal layers of the squamous epithelium, and in the ducts of the ESMGs, we developed an ex vivo porcine model of esophageal acid injury. In this model, esophageal tissue was placed in Ussing chambers to determine the effect of pretreatment with the ClC-2 agonist lubiprostone on tissue damage related to acid exposure. Pretreatment with lubiprostone significantly reduced the level of acid injury and significantly augmented the recovery of the injured tissue (P < 0.05). Evaluation of the interepithelial tight junctions showed well-defined membrane localization of occludin in lubiprostone-treated injured tissues. Pretreatment of tissues with the Na+-K+-2Cl- cotransporter inhibitor bumetanide blocked lubiprostone-induced increases in short-circuit current and inhibited the reparative effect of lubiprostone. Furthermore, inhibition of ClC-2 with ZnCl2 blocked the effects of lubiprostone. We conclude that ClC-2 contributes to esophageal protection from acid exposure, potentially offering a new therapeutic target.NEW & NOTEWORTHY This research is the first to describe the presence of anion channels ClC-2 and CFTR localized to the basal epithelia of porcine esophageal mucosa and the esophageal submucosal glands. In the setting of ex vivo acid exposure, the ClC-2 agonist lubiprostone reduced acid-related injury and enhanced recovery of the epithelial barrier. This work may ultimately provide an alternate mechanism for treating gastroesophageal reflux disease.

PMID: 32068440 [PubMed - indexed for MEDLINE]

Efficacy and safety of oral immunotherapy with AR101 in European children with a peanut allergy (ARTEMIS): a multicentre, double-blind, randomised, placebo-controlled phase 3 trial.

Lancet Child Adolesc Health. 2020 Jul 20;:

Authors: Hourihane JO, Beyer K, Abbas A, Fernández-Rivas M, Turner PJ, Blumchen K, Nilsson C, Ibáñez MD, Deschildre A, Muraro A, Sharma V, Erlewyn-Lajeunesse M, Zubeldia JM, De Blay F, Sauvage CD, Byrne A, Chapman J, Boralevi F, DunnGalvin A, O'Neill C, Norval D, Vereda A, Skeel B, Adelman DC, du Toit G

Abstract
BACKGROUND: Peanut allergy is the leading cause of food-related anaphylaxis. Current management options can negatively affect food allergy-related quality of life. We aimed to investigate the efficacy of an investigational oral biologic drug (AR101).
METHODS: The AR101 Trial in Europe Measuring Oral Immunotherapy Success in peanut-allergic children (ARTEMIS) trial was a multicentre, double-blind, randomised, placebo-controlled phase 3 trial done at 18 hospitals in Ireland, France, Germany, Italy, Spain, Sweden, and the UK. Children and adolescents with peanut allergy, aged 4-17 years, who developed dose-limiting symptoms to 300 mg or less peanut protein (equivalent to approximately one peanut kernel) during a double-blind placebo-controlled food challenge test at study entry were enrolled. Participants were randomly assigned (3:1) to receive daily doses of either AR101 oral immunotherapy (AR101 group) or a taste-masked placebo (placebo group). All participants, investigators, and care providers were masked to treatment allocation until the study was completed. Doses were increased every 2 weeks over 6 months until a dose of 300 mg was reached and maintained for 3 months. The primary endpoint was the proportion of participants in the intention-to-treat or safety population (defined as those participants who had been randomly assigned and had received at least one dose of the assigned drug) who could consume a single dose of 1000 mg (cumulative dose 2043 mg) peanut protein without developing dose-limiting allergic symptoms at an exit double-blind placebo-controlled food challenge after 9 months of treatment. Additional endpoints included safety (ie, the frequency and severity of adverse events) and changes in food allergy-related quality of life, assessed by use of age-appropriate Food Allergy Quality of Life Questionnaires (FAQLQs) and the Food Allergy Independent Measure (FAIM). The study is registered with ClinicalTrials.gov, NCT03201003, and is completed.
FINDINGS: Between June 12, 2017, and Feb 15, 2018, 227 patients were screened, of whom 175 were randomly assigned to the AR101 group (n=132) and the placebo group (n=43). All primary and secondary endpoints were met. 77 (58%) of 132 participants in the AR101 group tolerated 1000 mg peanut protein at the exit food challenge versus one (2%) of 43 participants in the placebo group (AR101-placebo treatment difference 56·0% [95% CI 44·1-65·2], p<0·0001). Adverse events were reported by almost all participants. The maximum severity of adverse events reported was mild or moderate for most participants who received AR101 (mild, 66 [50%] of 132 participants; moderate, 63 [48%]; and severe, one [1%]) or placebo (mild, 24 [56%] of 43 participants; moderate, 18 [42%]; severe, none). Participants aged 8-12 years in the AR101 group reported improvements that exceeded the minimum clinically important difference between the two groups across all FAQLQ domains. Additionally, participants in the AR101 group and their caregivers reported improvements that exceeded the minimum clinically important difference in FAIM domains related to the perceived likelihood and outcomes of a severe allergic reaction.
INTERPRETATION: AR101 oral immunotherapy treatment led to rapid desensitisation to peanut protein, with a predictable safety profile that improved with treatment, and an associated improvement in self-reported and caregiver-reported food allergy-related quality of life. These patient-oriented outcomes provide invaluable data to help physicians, patients, and caregivers make informed, shared decisions on the management of peanut allergy.
FUNDING: Aimmune Therapeutics.

PMID: 32702315 [PubMed - as supplied by publisher]

Low iron-induced small RNA BrrF regulates central metabolism and oxidative stress responses in Burkholderia cenocepacia.

PLoS One. 2020;15(7):e0236405

Authors: Sass AM, Coenye T

Abstract
Regulatory small RNAs play an essential role in maintaining cell homeostasis in bacteria in response to environmental stresses such as iron starvation. Prokaryotes generally encode a large number of RNA regulators, yet their identification and characterisation is still in its infancy for most bacterial species. Burkholderia cenocepacia is an opportunistic pathogen with high innate antimicrobial resistance, which can cause the often fatal cepacia syndrome in individuals with cystic fibrosis. In this study we characterise a small RNA which is involved in the response to iron starvation, a condition that pathogenic bacteria are likely to encounter in the host. BrrF is a small RNA highly upregulated in Burkholderia cenocepacia under conditions of iron depletion and with a genome context consistent with Fur regulation. Its computationally predicted targets include iron-containing enzymes of the tricarboxylic acid (TCA) cycle such as aconitase and succinate dehydrogenase, as well as iron-containing enzymes responsible for the oxidative stress response, such as superoxide dismutase and catalase. Phenotypic and gene expression analysis of BrrF deletion and overexpression mutants show that the regulation of these genes is BrrF-dependent. Expression of acnA, fumA, sdhA and sdhC was downregulated during iron depletion in the wild type strain, but not in a BrrF deletion mutant. TCA cycle genes not predicted as target for BrrF were not affected in the same manner by iron depletion. Likewise, expression of sodB and katB was dowregulated during iron depletion in the wild type strain, but not in a BrrF deletion mutant. BrrF overexpression reduced aconitase and superoxide dismutase activities and increased sensitivity to hydrogen peroxide. All phenotypes and gene expression changes of the BrrF deletion mutant could be complemented by overexpressing BrrF in trans. Overall, BrrF acts as a regulator of central metabolism and oxidative stress response, possibly as an iron-sparing measure to maintain iron homeostasis under conditions of iron starvation.

PMID: 32702060 [PubMed - as supplied by publisher]

Lethal mutations with fluctuating heterozygous effect: the lethal force of effective dominance.

J Hum Genet. 2020 Jul 22;:

Authors: Overall ADJ, Waxman D

Abstract
The theory of population genetics leads to the expectation that in very large populations the frequencies of recessive lethal mutations are close to the square root of the mutation rate, corresponding to mutation-selection balance. There are numerous examples where the frequencies of such alleles are orders of magnitude larger than this result. In this work we theoretically investigate the role of temporal fluctuations in the heterozygous effect (h) for lethal mutations in very large populations. For fluctuations of h, around a mean value of [Formula: see text], we find a biased outcome that is described by an effective dominance coefficient, heff, that is generally less than the mean dominance coefficient, i.e., [Formula: see text]. In the case where the mean dominance coefficient is zero, the effective dominance coefficient is negative: heff < 0, corresponding to the lethal allele behaving as though overdominant and having an elevated mean frequency. This case plausibly explains mean allele frequencies that are an order of magnitude larger than the equilibrium frequency of a recessive allele with a constant dominance coefficient. Our analysis may be relevant to explaining lethal disorders with anomalously high frequencies, such as cystic fibrosis and Tay-Sachs, and may open the door to further investigations into the statistics of fluctuations of the heterozygous effect.

PMID: 32699346 [PubMed - as supplied by publisher]

Spatiotemporal Distribution of Pseudomonas aeruginosa Alkyl Quinolones under Metabolic and Competitive Stress.

mSphere. 2020 Jul 22;5(4):

Authors: Cao T, Sweedler JV, Bohn PW, Shrout JD

Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen important to diseases such as cystic fibrosis. P. aeruginosa has multiple quorum-sensing (QS) systems, one of which utilizes the signaling molecule 2-heptyl-3-hydroxy-4-quinolone (Pseudomonas quinolone signal [PQS]). Here, we use hyperspectral Raman imaging to elucidate the spatiotemporal PQS distributions that determine how P. aeruginosa regulates surface colonization and its response to both metabolic stress and competition from other bacterial strains. These chemical imaging experiments illustrate the strong link between environmental challenges, such as metabolic stress caused by nutritional limitations or the presence of another bacterial species, and PQS signaling. Metabolic stress elicits a complex response in which limited nutrients induce the bacteria to produce PQS earlier, but the bacteria may also pause PQS production entirely if the nutrient concentration is too low. Separately, coculturing P. aeruginosa in the proximity of another bacterial species, or its culture supernatant, results in earlier production of PQS. However, these differences in PQS appearance are not observed for all alkyl quinolones (AQs) measured; the spatiotemporal response of 2-heptyl-4-hydroxyquinoline N-oxide (HQNO) is highly uniform for most conditions. These insights on the spatiotemporal distributions of quinolones provide additional perspective on the behavior of P. aeruginosa in response to different environmental cues.IMPORTANCE Alkyl quinolones (AQs), including Pseudomonas quinolone signal (PQS), made by the opportunistic pathogen Pseudomonas aeruginosa have been associated with both population density and stress. The regulation of AQ production is known to be complex, and the stimuli that modulate AQ responses are not fully clear. Here, we have used hyperspectral Raman chemical imaging to examine the temporal and spatial profiles of AQs exhibited by P. aeruginosa under several potentially stressful conditions. We found that metabolic stress, effected by carbon limitation, or competition stress, effected by proximity to other species, resulted in accelerated PQS production. This competition effect did not require cell-to-cell interaction, as evidenced by the fact that the addition of supernatants from either Escherichia coli or Staphylococcus aureus led to early appearance of PQS. Lastly, the fact that these modulations were observed for PQS but not for all AQs suggests a high level of complexity in AQ regulation that remains to be discerned.

PMID: 32699119 [PubMed - in process]

Pulmonary function testing in children's interstitial lung disease.

Eur Respir Rev. 2020 Sep 30;29(157):

Authors: Ring AM, Carlens J, Bush A, Castillo-Corullón S, Fasola S, Gaboli MP, Griese M, Koucky V, La Grutta S, Lombardi E, Proesmans M, Schwerk N, Snijders D, Nielsen KG, Buchvald F

Abstract
The use of pulmonary function tests (PFTs) has been widely described in airway diseases like asthma and cystic fibrosis, but for children's interstitial lung disease (chILD), which encompasses a broad spectrum of pathologies, the usefulness of PFTs is still undetermined, despite widespread use in adult interstitial lung disease. A literature review was initiated by the COST/Enter chILD working group aiming to describe published studies, to identify gaps in knowledge and to propose future research goals in regard to spirometry, whole-body plethysmography, infant and pre-school PFTs, measurement of diffusing capacity, multiple breath washout and cardiopulmonary exercise tests in chILD. The search revealed a limited number of papers published in the past three decades, of which the majority were descriptive and did not report pulmonary function as the main outcome.PFTs may be useful in different stages of management of children with suspected or confirmed chILD, but the chILD spectrum is diverse and includes a heterogeneous patient group in all ages. Research studies in well-defined patient cohorts are needed to establish which PFT and outcomes are most relevant for diagnosis, evaluation of disease severity and course, and monitoring individual conditions both for improvement in clinical care and as end-points in future randomised controlled trials.

PMID: 32699025 [PubMed - in process]

Differential adaptability between reference strains and clinical isolates of Pseudomonas aeruginosa into the lung epithelium intracellular lifestyle.

Virulence. 2020 Dec;11(1):862-876

Authors: Del Mar Cendra M, Torrents E

Abstract
Intracellular invasion is an advantageous mechanism used by pathogens to evade host defense and antimicrobial therapy. In patients, the intracellular microbial lifestyle can lead to infection persistence and recurrence, thus worsening outcomes. Lung infections caused by Pseudomonas aeruginosa, especially in cystic fibrosis (CF) patients, are often aggravated by intracellular invasion and persistence of the pathogen. Proliferation of the infectious species relies on a continuous deoxyribonucleotide (dNTP) supply, for which the ribonucleotide reductase enzyme (RNR) is the unique provider. The large genome plasticity of P. aeruginosa and its ability to rapidly adapt to different environments are challenges for studying the pathophysiology associated with this type of infection. Using different reference strains and clinical isolates of P. aeruginosa independently combined with alveolar (A549) and bronchial (16HBE14o- and CF-CFBE41o-) epithelial cells, we analyzed host-pathogen interactions and intracellular bacterial persistence with the aim of determining a cell type-directed infection promoted by the P. aeruginosa strains. The oscillations in cellular toxicity and oxygen consumption promoted by the intracellular persistence of the strains were also analyzed among the different infectious lung models. Significantly, we identified class II RNR as the enzyme that supplies dNTPs to intracellular P. aeruginosa. This discovery could contribute to the development of RNR-targeted strategies against the chronicity occurring in this type of lung infection. Overall our study demonstrates that the choice of bacterial strain is critical to properly study the type of infectious process with relevant translational outcomes.

PMID: 32697923 [PubMed - in process]

Mechanisms of action of a web-based intervention with health professional support to increase nebulizer adherence in adults with Cystic Fibrosis: a qualitative interview study.

J Med Internet Res. 2020 Jun 25;:

Authors: Drabble S, O'Cathain A, Scott AJ, Arden MA, Keating SM, Hutchings M, Maguire C, Wildman M

Abstract
BACKGROUND: Adherence to nebulizer treatments in adults with cystic fibrosis is often low. A new complex intervention to help adults with cystic fibrosis increase adherence to nebulizer treatments was tested in a pilot randomized controlled trial in two UK cystic fibrosis centers. Patients used a nebulizer with electronic monitoring capabilities that transferred data automatically to a digital platform (CFHealthHub) to monitor adherence over time, and a tailored website to display graphs of adherence data and educational and problem solving information about adherence. A trained interventionist helped patients to identify ways to increase their adherence.
OBJECTIVE: To explore the mechanisms of action of this complex intervention.
METHODS: A qualitative interview study undertaken concurrently with a pilot randomized controlled trial. 25 semi-structured interviews were conducted with three interventionists at two time points, 14 patients in the intervention arm of the trial, and five members of the multidisciplinary teams offering wider care to patients. A framework approach was used for analysis.
RESULTS: The intervention was informed by a theoretical framework of behavior change. There was evidence of the expected behavior change mechanisms of action. There was also evidence of Vassilev's mechanisms of action associated with effective telehealth interventions for self-management support: relationships, visibility, and fit. Patients described how building a relationship with the interventionist through face-to-face visits with someone who cared about them and their progress helped them to consider ways of increasing adherence to medication. Rather than seeing the visibility of adherence data to clinicians as problematic, patients found this motivating, particularly if they received praise about progress made. The intervention was tailored to individuals but there were challenges in how the intervention fitted into some patients' busy lives when delivered through a desktop computer.
CONCLUSIONS: Mechanisms associated with effective telehealth interventions for self-management operated within this new intervention. The intervention was modified to strengthen mechanisms of action based on these findings, for example delivery through an app accessed via mobile phones, and then tested in a randomized controlled trial in 19 UK cystic fibrosis centers.
CLINICALTRIAL: Registration: ISRCTN 13076797.

PMID: 32697197 [PubMed - as supplied by publisher]

Effectiveness of a multistep Pseudomonas aeruginosa eradication treatment protocol in children with cystic fibrosis in Brazil.

J Bras Pneumol. 2020;46(4):e20180294

Authors: Riquena B, Silva Filho LVRFD, Nakaie CMA, Almeida MB, Rodrigues JC, Adde FV

Abstract
OBJECTIVE: Although various strategies have been proposed for eradicating Pseudomonas aeruginosa in patients with cystic fibrosis (CF), only a few employ multistep treatment in children colonized by that pathogen for the first time. The aim of this study was to describe the effectiveness of a three-phase eradication protocol, initiated after the first isolation of P. aeruginosa, in children with CF in Brazil.
METHODS: This was a retrospective real-life study in which we reviewed the medical records of pediatric CF patients in whom the eradication protocol was applied between June of 2004 and December of 2012. The three-phase protocol was guided by positive cultures for P. aeruginosa in airway secretions, and the treatment consisted of inhaled colistimethate and oral ciprofloxacin. Success rates were assessed after each phase, as well as cumulatively.
RESULTS: During the study period, 47 episodes of P. aeruginosa colonization, in 29 patients, were eligible for eradication. Among the 29 patients, the median age was 2.7 years, 17 (59%) were male, and 19 (65%) had at least one F508del allele. All 29 patients completed the first phase of the protocol, whereas only 12 and 6 completed the second and third phases, respectively. Success rates for eradication in the three treatment phases were 58.6% (95% CI: 40.7-74.5), 50.0% (95% CI: 25.4-74.6), and 66.7% (95% CI: 30.0-90.3), respectively. The cumulative success rate was 93.1% (95% CI: 78.0-98.1). Treatment failure in all three phases occurred in only 2 patients.
CONCLUSIONS: In this sample of patients, the multistep eradication protocol was effective and had a high success rate.

PMID: 32696837 [PubMed - in process]