Risk factors associated with pulmonary exacerbations in pediatric patients with cystic fibrosis.

Arch Argent Pediatr. 2019 Oct 01;117(5):e466-e472

Authors: Lubovich S, Zaragoza S, Rodríguez V, Buendía J, Camargo Vargas B, Alchundia Moreira J, Galanternik L, Ratto P, Teper A

Abstract
INTRODUCTION: Cystic fibrosis patients develop pulmonary exacerbations (PEs) that require intravenous treatment. The objective of this study was to determine the risk factors associated with PEs and establish the percentage of patients who failed to recover their lung function.
POPULATION AND METHODS: Observational, retrospective, cohort study. The medical records of cystic fibrosis patients seen at Hospital de Niños Ricardo Gutiérrez in 2013 were reviewed. Patients were divided into group 1, with PE (Fuchs criteria), and group 2, without PE. Age, sex, p.F508del mutation, percentage of baseline forced expiratory volume in the first second, baseline body mass index Z-score, chronic Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex colonization (Leeds criteria), percentage of cystic fibrosis-related diabetes, and recovery of baseline forced expiratory volume in the first second were recorded.
RESULTS: A total of 117 patients were included. Group 1: 50, group 2: 67 patients. PEs were associated with a lower body mass index Z-score (RR: 1.45; p = 0.002), p.F508del mutation (RR: 3.23; p = 0.05), and chronic Burkholderia cepacia complex (RR: 3.69; p = 0.002), Pseudomonas aeruginosa (RR: 1.89; p = 0.01) and methicillinresistant Staphylococcus aureus colonization (RR: 2.32; p = 0.002). Twenty-four percent of patients failed to recover their lung function.
CONCLUSIONS: The presence of the p.F508del mutation, a poor nutritional status, and chronic colonization were the risk factors for exacerbation. A fourth of patients failed to recover their lung function.

PMID: 31560491 [PubMed - in process]

Course of lung function in children with cystic fibrosis in their first 3 years of life.

Arch Argent Pediatr. 2019 Oct 01;117(5):323-329

Authors: Balinotti JE, Chang DV, Lubovich S, Rodríguez V, Zaragoza S, Escobar N, Kofman C, Pérez GL, Ardiles V, Teper A

Abstract
INTRODUCTION: The early prevention of respiratory complications in children with cystic fibrosis is determining for a longer survival. The implementation of lung function tests in the first months of life allows to detect respiratory involvement, even in asymptomatic children.
OBJECTIVE: To assess the course of lung function in children with cystic fibrosis in their first 3 years of life and identify the factors affecting it.
POPULATION AND METHODS: Observational, retrospective, analytical study. Children younger than 36 months with at least 2 lung function tests were included.
RESULTS: Between 2008 and 2016, 48 patients were included; 85 % of them had been diagnosed by newborn screening. The first lung function test was done at 5 months old. The median Z-score of maximal flow at functional residual capacity was -0.05 (interquartile range: -1.09 to 1.08). The median change in the maximal flow Z-score between tests was -0.32 (interquartile range: -1.11 to 0.25), p = 0.045. Patients with Staphylococcus aureus respiratory infections, especially methicillin-resistant SA, evidenced a greater deterioration of lung function compared to those without infection. Neither sex nor the type of genetic mutation were associated with the course of lung function. Nutritional recovery throughout the study was really good.
CONCLUSION: Lung function in children with cystic fibrosis worsens progressively during their first 3 years of life. These findings are associated with Staphylococcus aureus respiratory infections.

PMID: 31560488 [PubMed - in process]

A rare clinical association: Barth syndrome and cystic fibrosis.

Turk J Pediatr. 2019;61(1):134-138

Authors: Sağ E, Kamaşak T, Kaya G, Çakır M

Abstract
Sağ E, Kamaşak T, Kaya G, Çakır M. A rare clinical association: Barth syndrome and cystic fibrosis. Turk J Pediatr 2019; 61: 134-138. Barth syndrome (BS) is a rare X-linked recessive metabolic disorder characterized by cardiomyopathy, hypotonia, neutropenia, growth retardation and 3-methylglutaconic aciduria type II. Cystic fibrosis is a common autosomal recessive genetic disorder in Caucasians. Herein, we reported a rare clinical association in an infant diagnosed based on clinical and genetic analysis. A six-month old boy admitted with chronic steatorrhea. The diagnosis of cystic fibrosis was made after clinical and laboratory examinations. Fifteen days later, the patient was presented with restlessness and moaning. He had hypoglycemia and lactic acidosis. The patient died three hours after the admission. Pedigree analysis revealed similar sudden infant deaths in close relatives. Postmortem genetic analysis revealed the diagnosis of Barth syndrome. This is the first case of the association of Barth syndrome with cystic fibrosis. Our case reinforces the importance of pedigree analysis and postmortem examinations.

PMID: 31559736 [PubMed - in process]

Nasal nitric oxide levels in primary ciliary dyskinesia, cystic fibrosis and healthy children.

Turk J Pediatr. 2019;61(1):20-25

Authors: Güney E, Emiralioğlu N, Cinel G, Yalçın E, Doğru D, Kiper N, Özçelik HU

Abstract
Güney E, Emiralioğlu N, Cinel G, Yalçın E, Doğru D, Kiper N, Özçelik HU. Nasal nitric oxide levels in primary ciliary dyskinesia, cystic fibrosis and healthy children. Turk J Pediatr 2019; 61: 20-25. Primary ciliary dyskinesia (PCD) is a rare, inherited disorder characterized by recurrent respiratory tract infections. The measurement of nasal nitric oxide (nNO) is an important test for the diagnosis of PCD. In this study, we aim to evaluate NIOX-MINOÒ, which is an easily applicable method for measuring nNO, in the diagnosis of patients with PCD and define diagnostic cut-off levels. Furthermore, determining the normal limits of nNO in healthy children and investigating nNO levels of children with cystic fibrosis (CF) are the other aims of this study. The children included in this study were 5 to 18.5 years old, 46 of them had PCD, 44 had CF and 200 were healthy children. To our knowledge, this work contains the widest population compared to previous studies. Subjects receiving steroids or antibiotics or those with any acute respiratory tract infection, asthma or allergic rhinitis were not included in the study. Mean nNO levels were found as 10.4, 22.8 and 21.0 ppb in PCD, CF and healthy children, respectively. The nNO levels for PCD patients were found significantly lower than children with CF and the control groups (p < 0.05). In this study, the diagnostic nNO cut-off level between PCD and the other two groups was determined to be < 11.5 ppb with %83.6 specificity and %67.4 sensitivity. The screening of nNO with NIOX-MINO method provides early diagnose before mucosal biopsy of patients who are suspected to have PCD and therefore, prevents co-morbidities and prolongs survival with early treatment.

PMID: 31559717 [PubMed - in process]

Incidence and clinical relevance of non-small cell lung cancer lymph node micro-metastasis detected by staging endobronchial ultrasound-guided transbronchial needle aspiration.

J Thorac Dis. 2019 Aug;11(8):3650-3658

Authors: Belanger AR, Hollyfield J, Yacovone G, Ceppe AS, Akulian JA, Burks AC, Rivera MP, Dodd LG, Long JM, Haithcock BE, Pecot CV

Abstract
Background: Approximately twenty percent of lymph node (LN) negative non-small cell lung cancer (NSCLC) patients who undergo curative intent surgery have pan-cytokeratin immunohistochemistry (IHC)-detectable occult micro-metastases (MMs) in resected LNs. The presence of the MMs in NSCLC is associated worsened outcomes. As a substantial proportion of NSCLC LN staging is conducted using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), we sought to determine the frequency of detection of occult MMs in EBUS-TBNA specimens and to evaluate the impact of MMs on progression-free and overall survival.
Methods: We performed retrospective IHC staining for pan-cytokeratin of EBUS-TBNA specimens previously deemed negative by a cytopathologist based on conventional hematoxylin and eosin staining. The results were correlated with clinical variables, including survival outcomes.
Results: Of 887 patients screened, 44 patients were identified meeting inclusion criteria with sufficient additional tissue for testing. With respect to the time of the EBUS-TBNA procedure, 52% of patients were clinical stage I, 34% clinical stage II, and clinical 14% stage IIIa NSCLC. Three patients (6.8%) were found to have cytokeratin positive MMs. All 3 MMs detected were at N2 LN stations. The presence of MMs was associated with significantly decreased progression-free (median 210 vs. 1,293 days, P=0.0093) and overall survival (median 239 vs. 1,120 days, P=0.0357).
Conclusions: Occult LN MMs can be detected in EBUS-TBNA specimens obtained during staging examinations and are associated with poor clinical outcomes. If prospectively confirmed, these results have significant implications for EBUS-TBNA specimen analyses and possibly for the NSCLC staging paradigm.

PMID: 31559073 [PubMed]

Management of Severe Asthma: a European Respiratory Society/American Thoracic Society Guideline.

Eur Respir J. 2019 Sep 26;:

Authors: Holguin F, Cardet JC, Chung KF, Diver S, Ferreira DS, Fitzpatrick A, Gaga M, Kellermeyer L, Khurana S, Knight S, McDonald VM, Morgan RL, Ortega VE, Rigau D, Subbarao P, Tonia T, Adcock IM, Bleecker ER, Brightling C, Boulet LP, Cabana M, Castro M, Chanez P, Custovic A, Djukanovic R, Frey U, Frankemolle B, Gibson P, Hamerlijnck D, Jarjour N, Konno S, Shen H, Vitary C, Bush A

Abstract
This document provides clinical recommendations for the management of severe asthma. Comprehensive evidence syntheses, including meta-analyses, were performed to summarise all available evidence relevant to the Task Force's questions. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach and the results were summarised in evidence profiles. The evidence syntheses were discussed and recommendations formulated by a multidisciplinary Task Force of asthma experts, who made specific recommendations on 6 specific questions. After considering the balance of desirable and undesirable consequences, quality of evidence, feasibility, and acceptability of various interventions, the Task Force made the following recommendations: 1) Suggest using anti-IL5 and anti IL-5Rα for severe uncontrolled adult eosinophilic asthma phenotypes; 2) suggest using blood eosinophil cut-point of ≥150/μL to guide anti-IL5 initiation in adult patients with severe asthma; and 3) Suggest considering specific eosinophil (≥260/μL) and FeNO (≥19.5 ppb) cutoffs to identify adolescents or adults with the greatest likelihood or response to anti-IgE therapy; 4) Suggest using inhaled tiotropium for adolescents and adults with severe uncontrolled asthma despite GINA step 4-5 or NAEPP step 5 therapies; 5) Suggest a trial of chronic macrolide therapy to reduce asthma exacerbations in persistently symptomatic or uncontrolled patients on GINA step 5 or NAEPP step 5 therapies, irrespective of asthma phenotype; 6) Suggest using anti-IL4/13 for adult patients with severe eosinophilic asthma, and for those with severe corticosteroid-dependent asthma regardless of blood eosinophil levels. These recommendations should be reconsidered as new evidence becomes available.

PMID: 31558662 [PubMed - as supplied by publisher]

Waardenburg Syndrome Type IV De Novo SOX10 Variant Causing Chronic Intestinal Pseudo-Obstruction.

Pediatr Gastroenterol Hepatol Nutr. 2019 Sep;22(5):487-492

Authors: Hogan AR, Rao KA, Thorson WL, Neville HL, Sola JE, Perez EA

Abstract
Waardenburg syndrome (WS) type IV is characterized by pigmentary abnormalities, deafness and Hirschsprung's disease. This syndrome can be triggered by dysregulation of the SOX10 gene, which belongs to the SOX (SRY-related high-mobility group-box) family of genes. We discuss the first known case of a SOX10 frameshift mutation variant defined as c.895delC causing WS type IV without Hirschsprung's disease. This female patient of unrelated Kuwaiti parents, who tested negative for cystic fibrosis and Hirschsprung's disease, was born with meconium ileus and malrotation and had multiple surgical complications likely due to chronic intestinal pseudo-obstruction. These complications included small intestinal necrosis requiring resection, development of a spontaneous fistula between the duodenum and jejunum after being left in discontinuity, and short gut syndrome. This case and previously reported cases demonstrate that SOX10 gene sequencing is a consideration in WS patients without aganglionosis but with intestinal dysfunction.

PMID: 31555574 [PubMed]

Exposure to Bile Leads to the Emergence of Adaptive Signaling Variants in the Opportunistic Pathogen Pseudomonas aeruginosa.

Front Microbiol. 2019;10:2013

Authors: Flynn S, Reen FJ, O'Gara F

Abstract
The chronic colonization of the respiratory tract by the opportunistic pathogen Pseudomonas aeruginosa is the primary cause of morbidity and mortality in cystic fibrosis (CF) patients. P. aeruginosa has been shown to undergo extensive genomic adaptation facilitating its persistence within the CF lung allowing it to evade the host immune response and outcompete co-colonizing residents of the lung microbiota. However, whilst several studies have described the various mutations that frequently arise in clinical isolates of P. aeruginosa, the environmental factors governing the emergence of these genetic variants is less well characterized. Gastro-oesophageal reflux has recently emerged as a major co-morbidity in CF and is often associated with the presence of bile acids in the lungs most likely by (micro) aspiration. In order to investigate whether bile may select for genetic variants, P. aeruginosa was experimentally evolved in artificial sputum medium, a synthetic media resembling environmental conditions found within the CF lung. Pigmented derivatives of P. aeruginosa emerged exclusively in the presence of bile. Genome sequencing analysis identified single nucleotide polymorphisms (SNPs) in quorum sensing (lasR) and both the pyocyanin (phzS) and pyomelanin (hmgA) biosynthetic pathways. Phenotypic analysis revealed an altered bile response when compared to the ancestral P. aeruginosa progenitor strain. While the recovered pigmented derivatives retained the bile mediated suppression of swarming motility and enhanced antibiotic tolerance, the biofilm, and redox responses to bile were abolished in the adapted mutants. Though loss of pseudomonas quinolone signal (PQS) production in the pigmented isolates was not linked to the altered biofilm response, the loss of redox repression could be explained by defective alkyl-quinolone (AQ) production in the presence of bile. Collectively, these findings suggest that the adaptive variants of P. aeruginosa that arise following long term bile exposure enables the emergence of ecologically competitive sub-populations. Altered pigmentation and AQ signaling may contribute to an enhancement in fitness facilitating population survival within a bile positive environment.

PMID: 31555243 [PubMed]

Coordinate regulation of ELF5 and EHF at the chr11p13 CF modifier region.

J Cell Mol Med. 2019 Sep 26;:

Authors: Swahn H, Sabith Ebron J, Lamar KM, Yin S, Kerschner JL, NandyMazumdar M, Coppola C, Mendenhall EM, Leir SH, Harris A

Abstract
E74-like factor 5 (ELF5) and ETS-homologous factor (EHF) are epithelial selective ETS family transcription factors (TFs) encoded by genes at chr11p13, a region associated with cystic fibrosis (CF) lung disease severity. EHF controls many key processes in lung epithelial function so its regulatory mechanisms are important. Using CRISPR/Cas9 technology, we removed three key cis-regulatory elements (CREs) from the chr11p13 region and also activated multiple open chromatin sites with CRISPRa in airway epithelial cells. Deletion of the CREs caused subtle changes in chromatin architecture and site-specific increases in EHF and ELF5. CRISPRa had most effect on ELF5 transcription. ELF5 levels are low in airway cells but higher in LNCaP (prostate) and T47D (breast) cancer cells. ATAC-seq in these lines revealed novel peaks of open chromatin at the 5' end of chr11p13 associated with an expressed ELF5 gene. Furthermore, 4C-seq assays identified direct interactions between the active ELF5 promoter and sites within the EHF locus, suggesting co-ordinate regulation between these TFs. ChIP-seq for ELF5 in T47D cells revealed ELF5 occupancy within EHF introns 1 and 6, and siRNA-mediated depletion of ELF5 enhanced EHF expression. These results define a new role for ELF5 in lung epithelial biology.

PMID: 31557407 [PubMed - as supplied by publisher]

[Polygenic risk prediction of common diseases: from epidemiology to clinical application].

Ned Tijdschr Geneeskd. 2019 Sep 24;163:

Authors: Jansen PR, Broeders MJM, Cornel MC, Meijers-Heijboer H

Abstract
Since the first map of the human genome was published in 2001 our knowledge about our genetic code has increased exponentially. In addition to high-risk genes for monogenic diseases, such as Huntington's disease and cystic fibrosis, for a number of common diseases, such as breast cancer and cardiovascular disease, many genetic variants that each have a slight increased-risk effect, have been identified via genome-wide association studies (GWAS). A polygenic risk score (PRS) can be calculated on the basis of these single-nucleotide polymorphisms (SNPs), by which an increasingly accurate prediction can be made of an individual's risk for diseases. The results of epidemiological studies in which a PRS is used to predict an individual's total genetic risk for particular diseases are promising. In the future, the PRS could be a valuable addition to traditional monogenic tests. It is, however, important that the predictive value of a genetic risk profile increases further and that it becomes more clear how a clinician must interpret this type of genetic profile - in combination with traditional risk factors.

PMID: 31556493 [PubMed - in process]

Clinical outcomes for cystic fibrosis patients with Pseudomonas aeruginosa cross-infections.

Pediatr Pulmonol. 2019 Sep 26;:

Authors: Milczewska J, Wołkowicz T, Zacharczuk K, Mierzejewska E, Kwiatkowska M, Walicka-Serzysko K, Sands D

Abstract
INTRODUCTION: Pseudomonas aeruginosa cross-infections are related to increased morbidity and mortality in cystic fibrosis (CF).
OBJECTIVES: The aim of the study was to evaluate the incidence of cross-infections with P. aeruginosa in children with CF.
METHODOLOGY: CF patients from whom at least one P. aeruginosa strain had been isolated were included in the study. The strain genotyping was performed using pulse-field gel electrophoresis. The history of contacts between patients was established based on questionnaires.
RESULTS: The study group consisted of 75 patients (aged 1.0-19.2 years) and the material included 170 P. aeruginosa strains. Cross-infections occurred in a group of 26 patients. In this group, the risk of the predicted occurrence of forced expiratory volume in 1 second ≤ 70% was five times greater and the risk of longer cumulative hospitalization time for intravenous antibiotic therapy (>14 days/year) was almost five times greater. In the clonal groups of strains, the multidrug-resistance rate was significantly higher than in other groups. In 2011, all tested strains were susceptible to colistin, whereas in 2012, three strains from the largest clonal group showed high levels of resistance to colistin.
CONCLUSION: Cross-infections with P. aeruginosa occurred in our group of patients and were associated with poor clinical outcomes. Antimicrobial resistance rate in the strains isolated from such infections was significantly higher, and this included three strains resistant to colistin.

PMID: 31556252 [PubMed - as supplied by publisher]

Technique and outcome of Domino Liver Transplantation from patients with Maple Syrup Urine Disease: Expanding the donor pool for Live Donor Liver Transplantation.

Clin Transplant. 2019 Sep 25;:e13721

Authors: Celik N, Kelly B, Soltys K, Squires JE, Vockley J, Shellmer DA, Strauss K, McKiernan P, Ganoza A, Sindhi R, Bond G, Mazariegos G, Khanna A

Abstract
AIM/BACKGROUND: Domino liver transplantation (DLT) using liver allografts from patients with metabolic disorders enhances organ utilization. Short and long-term course and outcome of these patients can impact the decision to offer this procedure to patients, especially those with diseases that can potentially be cured with liver transplant. We reviewed the outcomes of DLT from maple syrup urine disease (MSUD) patients in our large academic pediatric and adult transplant program.
METHODS: All patients receiving DLT were analyzed retrospectively with a minimum of one-year follow-up period for patient and donor characteristics, early and late postoperative complications and patient and graft survival with their MSUD donors in terms of age, weight, MELD/PELD scores, cold ischemia time, postoperative leucine levels and peak ALT (alanine aminotransferase) levels during the first 48 postoperative hours.
RESULTS: Between 2006 and May 2019, 21 patients underwent domino liver transplantation with live-donor allografts from MSUD patients. Four patients transplanted for different metabolic diseases are focus of a separate report . Seventeen patients with minimum one year follow up period are reported herein. The indications were primary sclerosing cholangitis (PSC, n=4), congenital hepatic fibrosis (CHF, n=2), alpha-1 antitrypsin deficiency (A-1 ATD, n=2), progressive familial intrahepatic cholestasis (PFIC, n=2), cystic fibrosis (n=1), primary biliary cirrhosis (PBC, n=1), neonatal hepatitis (n=1), embryonal sarcoma (n=1), Caroli disease (n=1), hepatocellular carcinoma (HCC, n=1), and chronic rejection after liver transplantations for PSC (n=1). All patients and grafts survived at median follow-up of 6.4 years (range 1.2-12.9 years). Median domino recipient age was 16.2 years (range 0.6-64.6 years) and median MSUD recipient age was 17.6 years (range 4.8-32.1 years). There were no vascular complications during the early postoperative period, one patient had portal vein thrombosis 3 years after DLT and a meso-Rex bypass was successfully performed. Small for size syndrome (SFSS) occurred in reduced left lobe DLT recipient and was managed successfully with conservative management. Biliary stricture developed in 2 patients and was resolved by stenting. Comparison between DLT and MSUD recipients' peak postoperative ALT results and PELD/MELD scores showed lower levels in DLT group (p-value<0.05).
CONCLUSIONS: Patient and graft survival in DLT from MSUD donors was excellent at short and long-term follow up. Metabolic functions have been normal in all recipients on a normal unrestricted protein diet. Ischemia preservation injury based on peak ALT was significantly decreased in DLT recipients. Domino transplantation from pediatric and adult recipients with selected metabolic diseases should be increasingly considered as an excellent option and alternative to deceased donor transplantation, thereby expanding the living donor pool. This, to date, is the largest world experience in DLT utilizing livers from patients with MSUD.

PMID: 31556146 [PubMed - as supplied by publisher]

Intestinal organoids in infants and children.

Pediatr Surg Int. 2019 Sep 25;:

Authors: Chusilp S, Li B, Lee D, Lee C, Vejchapipat P, Pierro A

Abstract
Recent advances in culturing of intestinal stem cells and pluripotent stem cells have led to the development of intestinal organoids. These are self-organizing 3D structures, which recapitulate the characteristics and physiological features of in vivo intestinal epithelium. Intestinal organoids have allowed the development of novel in vitro models to study various gastrointestinal diseases expanding our understanding of the pathophysiology of diseases and leading to the development of innovative therapies. This article aims to summarize the current usage of intestinal organoids as a model of gastrointestinal diseases and the potential applications of intestinal organoids in infants and children. Intestinal organoids allow the study of intestinal epithelium responses to stress factors. Mimicking intestinal injury such as necrotizing enterocolitis, intestinal organoids increases the expression of pro-inflammatory cytokine genes and shows disruption of tight junctions after they are injured by lipopolysaccharide and hypoxia. In cystic fibrosis, intestinal organoids derived from rectal biopsies have provided benefits in genetic studies and development of novel therapeutic gene modulation. Transplantation of intestinal organoids via enema has been shown to rescue damaged colonic epithelium in mice. In addition, tissue-engineered small intestine derived from intestinal organoids have been successfully established providing a potential novel treatment and a new hope for children with short bowel syndrome.

PMID: 31555860 [PubMed - as supplied by publisher]

Non-ribosomal Peptide Synthetase Gene Clusters in the Human Pathogenic Fungus Scedosporium apiospermum.

Front Microbiol. 2019;10:2062

Authors: Le Govic Y, Papon N, Le Gal S, Bouchara JP, Vandeputte P

Abstract
Scedosporium species are opportunistic fungi which preferentially affect patients with underlying conditions such as immunosuppression or cystic fibrosis (CF). While being the second most common molds capable to chronically colonize the CF lungs, the natural history of infection remains unclear. In filamentous fungi, a broad range of important secondary metabolites that are recognized as virulence factors are produced by multidomain non-ribosomal peptide synthetases (NRPSs). The aim of this study was to provide a global in silico analysis of NRPS-encoding genes based on the recently sequenced Scedosporium apiospermum genome. We uncovered a total of nine NRPS genes, of which six exhibited sufficient similarity scores with other fungal NRPSs to predict the class of the generated peptide: siderophores (n = 2), epidithiodioxopiperazines (n = 2), and cyclopeptides (n = 2). Phylogenetic trees based on the multiple alignments of adenylation (A) domain sequences corroborated these findings. Nevertheless, substrate prediction methods for NRPS A-domains tended to fail, thus questioning about the exact nature of the peptide produced. Further studies should be undertaken since NRPSs, which are not synthesized by human cells, could represent attractive therapeutic targets.

PMID: 31551992 [PubMed]

Pyoverdine-Dependent Virulence of Pseudomonas aeruginosa Isolates From Cystic Fibrosis Patients.

Front Microbiol. 2019;10:2048

Authors: Kang D, Revtovich AV, Chen Q, Shah KN, Cannon CL, Kirienko NV

Abstract
The development of therapies that modulate or prevent pathogen virulence may be a key strategy for circumventing antimicrobial resistance. Toward that end, we examined the production of pyoverdine, a key virulence determinant, in ∼70 Pseudomonas aeruginosa isolates from pediatric cystic fibrosis patients. Pyoverdine production was heterogeneous and showed a clear correlation with pathogenicity in Caenorhabditis elegans and an acute murine pneumonia model. Examination showed pyoverdine accumulation in host tissues, including extrapharyngeal tissues of C. elegans and lung tissues of mice, where accumulation correlated with host death. Many of the isolates tested were resistant to multiple antimicrobials, so we assayed the ability of pyoverdine inhibitors to mitigate virulence and rescue pyoverdine-mediated host pathology. Representatives from three different classes of pyoverdine inhibitors (gallium, fluoropyrimidines, and LK11) significantly improved survival. Our findings highlight the utility of targeting virulence factors in general, and pyoverdine in particular, as a promising method to control bacterial pathogenesis as the utility of antimicrobials continues to diminish.

PMID: 31551982 [PubMed]

Molecular and Microbial Microenvironments in Chronically Diseased Lungs Associated with Cystic Fibrosis.

mSystems. 2019 Sep 24;4(5):

Authors: Melnik AV, Vázquez-Baeza Y, Aksenov AA, Hyde E, McAvoy AC, Wang M, da Silva RR, Protsyuk I, Wu JV, Bouslimani A, Lim YW, Luzzatto-Knaan T, Comstock W, Quinn RA, Wong R, Humphrey G, Ackermann G, Spivey T, Brouha SS, Bandeira N, Lin GY, Rohwer F, Conrad DJ, Alexandrov T, Knight R, Dorrestein PC, Garg N

Abstract
To visualize the personalized distributions of pathogens and chemical environments, including microbial metabolites, pharmaceuticals, and their metabolic products, within and between human lungs afflicted with cystic fibrosis (CF), we generated three-dimensional (3D) microbiome and metabolome maps of six explanted lungs from three cystic fibrosis patients. These 3D spatial maps revealed that the chemical environments differ between patients and within the lungs of each patient. Although the microbial ecosystems of the patients were defined by the dominant pathogen, their chemical diversity was not. Additionally, the chemical diversity between locales in the lungs of the same individual sometimes exceeded interindividual variation. Thus, the chemistry and microbiome of the explanted lungs appear to be not only personalized but also regiospecific. Previously undescribed analogs of microbial quinolones and antibiotic metabolites were also detected. Furthermore, mapping the chemical and microbial distributions allowed visualization of microbial community interactions, such as increased production of quorum sensing quinolones in locations where Pseudomonas was in contact with Staphylococcus and Granulicatella, consistent with in vitro observations of bacteria isolated from these patients. Visualization of microbe-metabolite associations within a host organ in early-stage CF disease in animal models will help elucidate the complex interplay between the presence of a given microbial structure, antibiotics, metabolism of antibiotics, microbial virulence factors, and host responses.IMPORTANCE Microbial infections are now recognized to be polymicrobial and personalized in nature. Comprehensive analysis and understanding of the factors underlying the polymicrobial and personalized nature of infections remain limited, especially in the context of the host. By visualizing microbiomes and metabolomes of diseased human lungs, we reveal how different the chemical environments are between hosts that are dominated by the same pathogen and how community interactions shape the chemical environment or vice versa. We highlight that three-dimensional organ mapping methods represent hypothesis-building tools that allow us to design mechanistic studies aimed at addressing microbial responses to other microbes, the host, and pharmaceutical drugs.

PMID: 31551401 [PubMed]

Lung Inflammatory Environments Differentially Alter Mesenchymal Stromal Cell Behavior.

Am J Physiol Lung Cell Mol Physiol. 2019 Sep 25;:

Authors: Abreu SC, Enes SR, Dearborn J, Goodwin M, Coffey A, Borg ZD, Dos Santos CC, Wargo MJ, Cruz FF, Loi R, DeSarno M, Ashikaga T, Antunes MA, Rocco PRM, Liu KD, Lee JW, Matthay MA, McKenna DH, Weiss DJ

Abstract
Mesenchymal stromal (stem) cells (MSCs) are increasingly demonstrated to ameliorate experimentally-induced lung injuries through disease-specific anti-inflammatory actions, thus suggesting that different in vivo inflammatory environments can influence MSC actions. To determine the effects of different representative inflammatory lung conditions, human bone marrow-derived MSCs (hMSCs) were exposed to in vitro culture conditions from bronchoalveolar lavage fluid (BALF) samples obtained from patients with either the acute respiratory distress syndrome (ARDS) or with other lung diseases including acute respiratory exacerbations of cystic fibrosis (CF) (non-ARDS). hMSCs were subsequently assessed for time- and BALF concentration-dependent effects on mRNA expression of selected pro- and anti-inflammatory mediators, and for overall patterns of gene and mRNA expression. Both common and disease specific-patterns were observed in gene expression of different hMSC mediators, notably interleukin (IL)-6. Conditioned media obtained from non-ARDS BALF-exposed hMSCs was more effective in promoting an anti-inflammatory phenotype in monocytes than was conditioned media from ARDS BALF-exposed hMSCs. Neutralizing IL-6 in the conditioned media promoted generation of anti-inflammatory monocyte phenotype. These results demonstrated that different lung inflammatory environments differentially alter hMSC behavior. Further identification of these interactions and the driving mechanisms may influence clinical use of MSCs for treating lung diseases.

PMID: 31553626 [PubMed - as supplied by publisher]

Genomic and phenotypic comparison of environmental and patient-derived isolates of Pseudomonas aeruginosa suggest that antimicrobial resistance is rare within the environment.

J Med Microbiol. 2019 Sep 25;:

Authors: Ramsay KA, Wardell SJT, Patrick WM, Brockway B, Reid DW, Winstanley C, Bell SC, Lamont IL

Abstract
Patient-derived isolates of the opportunistic pathogen Pseudomonas aeruginosa are frequently resistant to antibiotics due to the presence of sequence variants in resistance-associated genes. However, the frequency of antibiotic resistance and of resistance-associated sequence variants in environmental isolates of P. aeruginosa has not been well studied. Antimicrobial susceptibility testing (ciprofloxacin, ceftazidime, meropenem, tobramycin) of environmental (n=50) and cystic fibrosis (n=42) P. aeruginosa isolates was carried out. Following whole genome sequencing of all isolates, 25 resistance-associated genes were analysed for the presence of likely function-altering sequence variants. Environmental isolates were susceptible to all antibiotics with one exception, whereas patient-derived isolates had significant frequencies of resistance to each antibiotic and a greater number of likely resistance-associated genetic variants. These findings indicate that the natural environment does not act as a reservoir of antibiotic-resistant P. aeruginosa, supporting a model in which antibiotic susceptible environmental bacteria infect patients and develop resistance during infection.

PMID: 31553303 [PubMed - as supplied by publisher]

Pepsin Triggers Neutrophil Migration Across Acid Damaged Lung Epithelium.

Sci Rep. 2019 Sep 24;9(1):13778

Authors: Hurley BP, Jugo RH, Snow RF, Samuels TL, Yonker LM, Mou H, Johnston N, Rosen R

Abstract
Pepsin represents a potential biomarker for extraesophageal reflux disease when detected in airways, however a direct role for pepsin in lung dysfunction has not been clearly established. Children experiencing gastroesophageal and extraesophageal reflux are often prescribed proton pump inhibitors (PPIs) to reduce gastric acid associated damage to esophageal and airway mucosa. The potential of pepsin and gastric fluid, from children that were either on or off PPI therapy, to cause inflammation and damage using a human in vitro co-culture model of the airway mucosa was evaluated herein. Exposure of the airway model to acidic solutions caused cellular damage and loss of viability, however, acid alone did not disrupt barrier integrity or instigate neutrophil trans-epithelial migration without pepsin. Gastric fluid from patients on PPI therapy exhibited only a slightly higher pH yet had significantly higher concentrations of pepsin and elicited more barrier disruption and neutrophil trans-epithelial migration compared to gastric fluid from patients off PPIs. Inflammatory and damaging responses observed with gastric fluid from patients on PPIs were largely driven by pepsin. These results indicate the potential for PPI usage to raise concentrations of pepsin in gastric fluid, which may enhance the pathological impact of micro-aspirations in children with extraesophageal reflux.

PMID: 31551494 [PubMed - in process]

Short-term consequences of F508del-CFTR thermal instability on CFTR-dependent transepithelial currents in human airway epithelial cells.

Sci Rep. 2019 Sep 24;9(1):13729

Authors: Froux L, Coraux C, Sage E, Becq F

Abstract
Loss-of-function mutations in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) channel in human airway epithelial cells are responsible for Cystic Fibrosis. A deleterious impact of physiological temperature on CFTR plasma membrane expression, residence and channel activity is characteristic of the most common and severe CF mutation, F508del. Using primary human F508del-airway epithelial cells and CF bronchial epithelial CFBE41o- cell lines expressing F508del- or WT-CFTR, we examined the effects of temperature (29 °C-39 °C) on the amplitude and stability of short-circuit CFTR-dependent currents over time and the efficiency of pharmacological strategies to stably restore F508del-CFTR function. We show that F508del-CFTR functional instability at 37 °C is not prevented by low temperature or VX-809 correction, genistein and VX-770 potentiators, nor by the combination VX-809/VX-770. Moreover, F508del-CFTR-dependent currents 30 minutes after CFTR activation at 37 °C did not significantly differ whether a potentiator was used or not. We demonstrate that F508del-CFTR function loss is aggravated at temperatures above 37 °C while limited by a small decrease of temperature and show that the more F508del-CFTR is stimulated, the faster the current loss happens. Our study highlights the existence of a temperature-dependent process inhibiting the function of F508del-CFTR, possibly explaining the low efficacy of pharmacological drugs in clinic.

PMID: 31551433 [PubMed - in process]