Aspergillus Infections and Progression of Structural Lung Disease in Children with Cystic Fibrosis.

Am J Respir Crit Care Med. 2019 Nov 20;:

Authors: Breuer O, Schultz A, Garratt LW, Turkovic L, Rosenow T, Murray CP, Karpievitch YV, Akesson L, Dalton S, Sly PD, Ranganathan S, Stick SM, Caudri D, AREST CF

Abstract
RATIONALE: Recent data show that Aspergillus species are prevalent respiratory infections in children with cystic fibrosis (CF). The biological significance of these infections is unknown.
OBJECTIVES: We aimed to evaluate longitudinal associations between Aspergillus infections and lung disease in young children with CF.
METHODS: Longitudinal data on 330 children participating in the Australian Respiratory Early Surveillance Team for Cystic Fibrosis surveillance program between 2000-2018 who underwent annual chest computed tomography (CT) and bronchoalveolar lavage (BAL) were used to determine the association between Aspergillus infections and the progression of structural lung disease. Results were adjusted for the effects of other common infections, associated variables and repeated visits. Secondary outcomes included inflammatory markers in BAL, respiratory symptoms and admissions for exacerbations.
RESULTS: H. influenzae, S. aureus, P. aeruginosa and Aspergillus infections were all associated with worse CT scores in the same year (poverall<0.05). Only P. aeruginosa and Aspergillus were associated with progression in CT scores in the year following an infection and worse CT scores at the end of the observation period. P. aeruginosa was most significantly associated with development of bronchiectasis (difference 0.9; 95%CI, 0.3-1.6; p=0.003) and Aspergillus with trapped-air (difference 3.2; 95%CI, 1.0-5.4; p=0.004). Aspergillus infections were also associated with markers of neutrophilic inflammation (p<0.001) and respiratory admissions risk (p=0.008).
CONCLUSION: Lower respiratory Aspergillus infections are associated with the progression of structural lung disease in young children with CF. This study highlights the need to further evaluate early Aspergillus species infections and the feasibility, risk and benefit of eradication regimens.

PMID: 31747309 [PubMed - as supplied by publisher]

Agonism of the TMEM16A Calcium-Activated Chloride Channel Modulates Airway Smooth Muscle Tone.

Am J Physiol Lung Cell Mol Physiol. 2019 Nov 20;:

Authors: Danielsson J, Kuforiji AS, Yocum GT, Zhang Y, Xu D, Gallos G, Emala CW

Abstract
TMEM16A (anoctamin 1) is an important calcium-activated chloride channel (CaCC) in airway smooth muscle (ASM). We have previously shown that TMEM16A antagonists such as benzbromarone relax ASM and have proposed TMEM16A antagonists as novel therapies for asthma treatment. However, TMEM16A is also expressed on airway epithelium, and TMEM16A agonists are being investigated as novel therapies for cystic fibrosis. There are theoretical concerns that agonism of TMEM16A on ASM could lead to bronchospasm making them detrimental as airway therapeutics. The TMEM16A agonist Eact induced a significant contraction of human ASM and guinea pig tracheal rings in an ex vivo organ bath model. Pretreatment with two different TMEM16A antagonists, benzbromarone or T16Ainh-A01, completely attenuated these Eact-induced contractions. Pretreatment with Eact alone augmented the maximum acetylcholine contraction. Pretreatment of A/J mice in vivo with nebulized Eact caused an augmentation of methacholine-induced increases in airway resistance measured by the forced oscillatory technique (Flexivent{trade mark, serif}). Pretreatment with the TMEM16A antagonist benzbromarone significantly attenuated methacholine-induced increases in airway resistance. In in vitro cellular studies, TMEM16A was found to be expressed more abundantly in ASM compared to epithelial cells in culture (8 fold higher in ASM). Eact caused an increase in intracellular calcium in human ASM cells which was completely attenuated by pretreatment with benzbromarone. Eact acutely depolarized the plasma membrane potential of ASM cells which was attenuated by benzbromarone or nifedipine. The TMEM16A agonist Eact modulates ASM contraction in both ex vivo and in vivo models, suggesting that agonism of TMEM16A may lead to clinically relevant bronchospasm.

PMID: 31747299 [PubMed - as supplied by publisher]

Systematic genetic analysis of the MHC region reveals mechanistic underpinnings of HLA type associations with disease.

Elife. 2019 Nov 20;8:

Authors: D'Antonio M, Reyna J, Jakubosky D, Donovan MK, Bonder MJ, Matsui H, Stegle O, Nariai N, D'Antonio-Chronowska A, Frazer KA

Abstract
The MHC region is highly associated with autoimmune and infectious diseases. Here we conduct an in-depth interrogation of associations between genetic variation, gene expression and disease. We create a comprehensive map of regulatory variation in the MHC region using WGS from 419 individuals to call eight-digit HLA types and RNA-seq data from matched iPSCs. Building on this regulatory map, we explored GWAS signals for 4,083 traits, detecting colocalization for 180 disease loci with eQTLs. We show that eQTL analyses taking HLA type haplotypes into account have substantially greater power compared with only using single variants. We examined the association between the 8.1 ancestral haplotype and delayed colonization in Cystic Fibrosis, postulating that downregulation of RNF5 expression is the likely causal mechanism. Our study provides insights into the genetic architecture of the MHC region and pinpoints disease associations that are due to differential expression of HLA genes and non-HLA genes.

PMID: 31746734 [PubMed - as supplied by publisher]

Lung function changes before and after pulmonary exacerbation antimicrobial treatment in cystic fibrosis.

Pediatr Pulmonol. 2019 Nov 20;:

Authors: Wagener JS, VanDevanter DR, Konstan MW, Pasta DJ, Millar SJ, Morgan WJ

Abstract
BACKGROUND: In cystic fibrosis, observation of a lung function drop (as percent predicted forced expiratory volume in 1 s [FEV1 ]; ppFEV1 ) frequently precedes pulmonary exacerbation (PEx) diagnosis. Recovery of ppFEV1 to a previous "baseline" is commonly used to assess antimicrobial treatment response. However, not all diagnosed PEx are associated with a ppFEV1 drop, and it is unclear whether these are a different type of PEx from those associated with a ppFEV1 drop.
METHODS: We analyzed pre- and posttreatment ppFEV1 for PEx recorded in the Epidemiologic Study of Cystic Fibrosis from 2003 through 2005. Baseline, pretreatment, and follow-up ppFEV1 were the best recorded within 12-months pre-PEx, the lowest recorded -30 to +3 days of treatment, and the best recorded during 6-month follow-up, respectively. Logistic regression models for return of ppFEV1 to baseline during follow-up were developed separately for PEx with ≥10%, <10%, and no ppFEV1 drop before treatment.
RESULTS: Of 15 147 PEx, 10 166 (67.1%), 3479 (23.0%), and 1502 (9.9%) presented with a ≥10%, <10%, or no ppFEV1 drop at diagnosis, respectively. 19.5%, 35.2%, and 65.6% of PEx, respectively, had follow-up ppFEV1 equal to or exceeding baseline; overall 27.7% of all PEx treatments resulted in complete recovery of baseline ppFEV1 . Significant predictors of ppFEV1 recovery at follow-up were younger patient age, absence of Aspergillus, lower baseline ppFEV1 , fewer visits during the baseline, lower frequency of prior-year PEx, shorter elapsed time from baseline measure to treatment, smaller relative ppFEV1 drop before treatment, and non intravenous (ie, oral or inhaled antibiotic) treatment. PEx with ≥10%, <10%, and no ppFEV1 drop before treatment had only modest differences in covariate odds ratios associated with complete ppFEV1 recovery.
CONCLUSIONS: Among the 10% of PEx presenting with no apparent ppFEV1 drop, more than one-third resulted in a decreased ppFEV1 during follow-up. Risk factors for this outcome were the same as those associated with lack of ppFEV1 recovery among PEx with pretreatment ppFEV1 drops. These results suggest that inherent FEV1 variability, baseline and follow-up sampling methodologies, ppFEV1 regression to the mean, and underlying lung disease progression complicate this approach for assessing effects of PEx and treatment response.

PMID: 31746561 [PubMed - as supplied by publisher]

Review of a 7-year record of the bacteriological profile of airway secretions of children with cystic fibrosis in North India.

Indian J Med Microbiol. 2019 Apr-Jun;37(2):203-209

Authors: Gautam V, Kaza P, Mathew JL, Kaur V, Sharma M, Ray P

Abstract
Background: Cystic fibrosis (CF) is now a recognised entity in India, with prevalence rates between 1/10,000 and 1/50,000. However, no data were available with regard to the profile of respiratory pathogens in the Indian setting.
Materials and Methods: The records of respiratory secretion bacterial cultures of children with CF in a tertiary care hospital in North India from January 2010 to December 2016 were reviewed. Culture data were evaluated; the organisms were noted and their antimicrobial susceptibilities were analysed. The microbiological profile and antimicrobial susceptibility pattern of CF patients were evaluated.
Results: A total of 445 samples from 146 children were processed, of which 246 (55%) samples showed bacterial growth. Mixed infections 48 (19.5%) were common in older children. Children aged 3-6 months (62.5%) showed the highest culture positivity. The most commonly isolated organisms were Pseudomonas aeruginosa (52.6%) and Staphylococcus aureus. Children with initial cultures positive for P. aeruginosa had 55% of their subsequent cultures showing polymicrobial infections. P. aeruginosa was most susceptible to ciprofloxacin (89%) and piperacillin-tazobactum (88%). Among the staphylococcal isolates, 38% were methicillin-resistant S. aureus (MRSA). The percentage of MRSA increased from 66% in 2010 to 75% in 2012, followed by a decline to 24% in 2016.
Conclusions: The pattern of airway colonisation in the Indian setting is different from the Caucasian population, and P. aeruginosa and Burkholderia cepacia complex appear early. Colonisation with P. aeruginosa benefits from therapy. In case of infection, care must be taken while initiating empiric therapy. It should be based on local antibiograms to prevent the emergence of resistant microbes.

PMID: 31745020 [PubMed - in process]

The Staphylococcus aureus Transcriptome during Cystic Fibrosis Lung Infection.

MBio. 2019 Nov 19;10(6):

Authors: Ibberson CB, Whiteley M

Abstract
Laboratory models have been invaluable for the field of microbiology for over 100 years and have provided key insights into core aspects of bacterial physiology such as regulation and metabolism. However, it is important to identify the extent to which these models recapitulate bacterial physiology within a human infection environment. Here, we performed transcriptomics (RNA-seq), focusing on the physiology of the prominent pathogen Staphylococcus aureus in situ in human cystic fibrosis (CF) infection. Through principal-component and hierarchal clustering analyses, we found remarkable conservation in S. aureus gene expression in the CF lung despite differences in the patient clinic, clinical status, age, and therapeutic regimen. We used a machine learning approach to identify an S. aureus transcriptomic signature of 32 genes that can reliably distinguish between S. aureus transcriptomes in the CF lung and in vitro The majority of these genes were involved in virulence and metabolism and were used to improve a common CF infection model. Collectively, these results advance our knowledge of S. aureus physiology during human CF lung infection and demonstrate how in vitro models can be improved to better capture bacterial physiology in infection.IMPORTANCE Although bacteria have been studied in infection for over 100 years, the majority of these studies have utilized laboratory and animal models that often have unknown relevance to the human infections they are meant to represent. A primary challenge has been to assess bacterial physiology in the human host. To address this challenge, we performed transcriptomics of S. aureus during human cystic fibrosis (CF) lung infection. Using a machine learning framework, we defined a "human CF lung transcriptome signature" that primarily included genes involved in metabolism and virulence. In addition, we were able to apply our findings to improve an in vitro model of CF infection. Understanding bacterial gene expression within human infection is a critical step toward the development of improved laboratory models and new therapeutics.

PMID: 31744924 [PubMed - in process]

Pseudomonas aeruginosa Leucine Aminopeptidase Influences Early Biofilm Composition and Structure via Vesicle-Associated Antibiofilm Activity.

MBio. 2019 Nov 19;10(6):

Authors: Esoda CN, Kuehn MJ

Abstract
Pseudomonas aeruginosa, known as one of the leading causes of disease in cystic fibrosis (CF) patients, secretes a variety of proteases. These enzymes contribute significantly to P. aeruginosa pathogenesis and biofilm formation in the chronic colonization of CF patient lungs, as well as playing a role in infections of the cornea, burn wounds, and chronic wounds. We previously characterized a secreted P. aeruginosa peptidase, PaAP, that is highly expressed in chronic CF isolates. This leucine aminopeptidase is highly expressed during infection and in biofilms, and it associates with bacterial outer membrane vesicles (OMVs), structures known to contribute to virulence mechanisms in a variety of Gram-negative species and one of the major components of the biofilm matrix. We hypothesized that PaAP may play a role in P. aeruginosa biofilm formation. Using a lung epithelial cell/bacterial biofilm coculture model, we show that PaAP deletion in a clinical P. aeruginosa background alters biofilm microcolony composition to increase cellular density, while decreasing matrix polysaccharide content, and that OMVs from PaAP-expressing strains but not PaAP alone or in combination with PaAP deletion strain-derived OMVs could complement this phenotype. We additionally found that OMVs from PaAP-expressing strains could cause protease-mediated biofilm detachment, leading to changes in matrix and colony composition. Finally, we showed that the OMVs could also mediate the detachment of biofilms formed by both nonself P. aeruginosa strains and Klebsiella pneumoniae, another respiratory pathogen. Our findings represent novel roles for OMVs and the aminopeptidase in the modulation of P. aeruginosa biofilm architecture.IMPORTANCE Biofilm formation by the bacterial pathogen P. aeruginosa is known to contribute to drug resistance in nosocomial infections and chronic lung infections of cystic fibrosis patients. In order to treat these infections more successfully, the mechanisms of bacterial biofilm development must be elucidated. While both bacterially secreted aminopeptidase and outer membrane vesicles have been shown to be abundant in P. aeruginosa biofilm matrices, the contributions of each of these factors to the steps in biofilm generation have not been well studied. This work provides new insight into how these bacterial components mediate the formation of a robust, drug-resistant extracellular matrix and implicates outer membrane vesicles as active components of biofilm architecture, expanding our overall understanding of P. aeruginosa biofilm biology.

PMID: 31744920 [PubMed - in process]

How to perform and interpret the sweat test.

Arch Dis Child Educ Pract Ed. 2019 Nov 19;:

Authors: Brown A, Jenkins L, Reid A, Leavy A, McDowell G, McIlroy C, Thompson A, McNaughten B

Abstract
Cystic fibrosis (CF) is the most common life-threatening autosomal-recessive disease affecting Caucasians in the western world. The sweat test is the main diagnostic test for CF. It is indicated as part of the clinical assessment for infants that have picked up on the national neonatal screening programme. It may also be requested where clinical suspicion of a diagnosis of CF exists despite normal screening results. This article outlines the physiological basis behind sweat testing and the technical aspects of performing the test. Indications for performing the test are also considered. The article aims to provide clinicians with a guide to interpretation of results.

PMID: 31744807 [PubMed - as supplied by publisher]

Prevalence and importance of non-tuberculous mycobacteria in adult patients with cystic fibrosis in a hospital in Madrid.

Enferm Infecc Microbiol Clin. 2019 Nov 16;:

Authors: Fernández-Caso B, Vázquez R, Alarcón T, Girón R, López-Giménez MR, Domingo D

Abstract
INTRODUCTION: The role of non-tuberculous mycobacteria (NTM) among cystic fibrosis (CF) patients, on occasion, remains unknown. The aim of our study is to evaluate the prevalence and clinical/microbiological characteristics of CF adult patients colonized by NTM, highlighting Mycobacterium abscessus (M. abscessus).
METHODS: A retrospective study was conducted with 92 CF adult patients: including a control group of 64 patients, not colonized by NTM, and a study group of 28 patients, colonized by NTM. We have analyzed variables such as age, F508del mutation, lung function, pancreatic involvement, auramine staining and co-colonizations between both groups.
RESULTS: The prevalence of NTM found was 30.4%. The most prevalent was Mycobacterium avium complex followed by M. abscessus. For M. abscessus, in the comparative study with patients colonized by other NTM, significant results were obtained for variables age.
DISCUSSION: We have found a high prevalence of NTM among adult patients with CF, and we associated the presence of M. asbcessus with ages less than 30 years and F508del. Due to the pathogenic role of NTM, especially M. asbcessus, multicenter studies are required within the population suffering from CF.

PMID: 31744623 [PubMed - as supplied by publisher]

Biomarkers for diagnosis of Wilson's disease.

Cochrane Database Syst Rev. 2019 Nov 19;2019(11):

Authors: Ryan A, Nevitt SJ, Tuohy O, Cook P

Abstract
BACKGROUND: Wilson's disease, first described by Samuel Wilson in 1912, is an autosomal recessive metabolic disorder resulting from mutations in the ATP7B gene. The disease develops as a consequence of copper accumulating in affected tissues. There is no gold standard for the diagnosis of Wilson's disease, which is often delayed due to the non-specific clinical features and the need for a combination of clinical and laboratory tests for diagnosis. This delay may in turn affect clinical outcome and has implications for other family members in terms of diagnosis. The Leipzig criteria were established to help standardise diagnosis and management. However, it should be emphasised that these criteria date from 2003, and many of these have not been formally evaluated; this review examines the evidence behind biochemical testing for Wilson's disease.
OBJECTIVES: To determine the diagnostic accuracy of three biochemical tests at specified cut-off levels for Wilson's disease. The index tests covered by this Cochrane Review are caeruloplasmin, 24-hour urinary copper and hepatic copper content. These tests were evaluated in those with suspected Wilson's disease and appropriate controls (either healthy or those with chronic liver disease other than Wilson's). In the absence of a gold standard for diagnosing Wilson's disease, we have used the Leipzig criteria as a clinical reference standard. To investigate whether index tests should be performed in all individuals who have been recommended for testing for Wilson's disease, or whether these tests should be limited to subgroups of individuals.
SEARCH METHODS: We identified studies by extensive searching of, e.g. the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, the Web of Science and clinical trial registries (29 May 2019). Date of the most recent search of the Cochrane Cystic Fibrosis and Genetic Disorders Inborn Errors of Metabolism Register: 29 May 2019.
SELECTION CRITERIA: We included prospective and retrospective cohort studies that assessed the diagnostic accuracy of an index test using the Leipzig criteria as a clinical reference standard for the diagnosis of Wilson's disease.
DATA COLLECTION AND ANALYSIS: Two review authors independently reviewed and extracted data and assessed the methodological quality of each included study using the QUADAS-2 tool. We had planned to undertake meta-analyses of the sensitivity, specificity at relevant cut-offs for each of the biochemical tests for Wilson's, however, due to differences in the methods used for each biochemical index test, it was not possible to combine the results in meta-analyses and hence these are described narratively.
MAIN RESULTS: Eight studies, involving 5699 participants (which included 1009 diagnosed with Wilson's disease) were eligible for inclusion in the review. Three studies involved children only, one adults only and the four remaining studies involved both children and adults. Two evaluated participants with hepatic signs and six with a combination of hepatic and neurological signs and symptoms of Wilson's disease, as well as pre-symptomatic individuals. The studies were of variable methodological quality; with high risk if bias for participant selection and the reference standard used being of greatest methodological concern. Key differences between studies include differences in assay methodology, different cut-off values for diagnostic thresholds, different age and ethnicity groups. Concerns around study design imply that diagnostic accuracy figures may not transfer to populations outside of the relevant study.
INDEX TEST: caeruloplasmin Five studies evaluated various thresholds of caeruloplasmin (4281 participants, of which 541 had WD). For caeruloplasmin a cut-off of 0.2 g/L as in the Leipzig criteria achieved a sensitivity of 77.1% to 99%, with variable specificity of 55.9% to 82.8%. Using the cut-off of 0.1 g/L of the Leipzig criteria seemed to lower the sensitivity overall, 65% to 78.9%, while increasing the specificity to 96.6% to 100%.
INDEX TEST: hepatic copper Four studies evaluated various thresholds of hepatic copper (1150 participants, of which 367 had WD). The hepatic copper cut-off of 4 μmol/g used in the Leipzig criteria achieved a sensitivity of 65.7% to 94.4%, with a variable specificity of 52.2% to 98.6%.
INDEX TEST: 24-hour urinary copper Three studies evaluated various thresholds of 24-hour urinary copper (268 participants, of which 101 had WD). For 24-hour urinary copper, a cut-off of 0.64 to 1.6 μmol/24 hours used in the Leipzig criteria achieved a variable sensitivity of 50.0% to 80.0%, with a specificity of 75.6% to 98.3%.
AUTHORS' CONCLUSIONS: The cut-offs used for caeruloplasmin, 24-hour urinary copper and hepatic copper for diagnosing Wilson's disease are method-dependent and require validation in the population in which such index tests are going to be used. Binary cut-offs and use of single-test strategies to rule Wilson's disease in or out is not supported by the evidence in this review. There is insufficient evidence to inform testing in specific subgroups, defined by age, ethnicity or clinical subgroups.

PMID: 31743430 [PubMed - in process]

Perspiration interventions for conservative management of kidney disease and uremia.

Curr Opin Nephrol Hypertens. 2019 Nov 16;:

Authors: Keller RW, Kopple JD, Kalantar-Zadeh K

Abstract
PURPOSE OF REVIEW: There has been an increasing interest in developing novel technologies to treat patients with chronic kidney disease as evidenced by KidneyX, the public-private partnership between government and industry. Perhaps a simple technology for treating kidney failure would be to utilize perspiration. It is a physiological process, and when used properly it might not be an unpleasant experience. This review will explore the current state of knowledge regarding perspiration therapy in the setting of far advanced kidney failure.
RECENT FINDINGS: A literature review using the PubMed database was conducted between 1 April 2019 and 3 September 2019. Search terms are shown in Table 1. Major themes of the results include diaphoresis therapy for patients with chronic kidney disease, excessive perspiration causing kidney disease, analysis of sweat to diagnose cystic fibrosis, and analysis of sweat to replenish lost electrolytes. This review will focus on intentional perspiration for the treatment of patients with end-stage renal disease (ESRD). Studies have shown that perspiration, or sweat-based therapies, can provide some of the most important currently recognized therapeutic goals in treating ESRD. These goals include decreased interdialytic weight gain, reduced serum potassium levels, and benefits to cardiovascular status. Research has shed light on some of the mechanisms, both molecular and clinical, that may be involved in induced perspiration therapy in ESRD.
SUMMARY: There is a long history of humans using perspiration for both recreation and therapy. Perspiration therapy for ESRD experienced a surge in the United States in the 1960s but does not have much modern momentum. With the continued growth of the ESRD population worldwide this could be considered an appropriate time to conduct more research into this promising therapy.

PMID: 31743242 [PubMed - as supplied by publisher]

Serum chemerin level, cytokine profile and nutritional status in children with cystic fibrosis.

Acta Biochim Pol. 2019 Nov 14;:

Authors: Sznurkowska K, Kaźmierska K, Śledziński T, Zagierski M, Liberek A, Szlagatys-Sidorkiewicz A

Abstract
BACKGROUND: Cystic fibrosis (CF) is characterized by malnutrition and chronic inflammation predominantly occurring in lungs. Evidence suggests a relation between inflammatory activity and nutritional status. Proinflammatory cytokines, playing crucial role in pulmonary destruction in CF, are regarded as a component of the pathogenesis of illness-related malnutrition. Chemerin - a novel marker of a crosstalk between nutrition and inflammation, has not been investigated in children with cystic fibrosis. The aim of this study was to determine serum level of chemerin, interleukin-1b (IL-1b), interleukin-6 (IL-6), tumor necrosing factor α (TNF-α) and interleukin-10 (IL-10) and to verify if they correlate with the nutritional status in children with CF.
METHODS: The study included 72 pediatric patients with cystic fibrosis. The control group was comprised of 30 healthy children. Nutritional status parameters: Body Mass Index (BMI), fat mass percentage (FM %) and fat free mass percentage (FFM%) have been assessed in all the subjects basing on bioimpedance and anthropometry according to Slaughter. Serum concentrations of chemerin and cytokines were estimated with ELISA.
RESULTS: No statistically significant difference in serum chemerin was found between the studied and the control group. We have documented a significantly higher level of IL-1b, IL-6, TNF-α and IL-10 in CF patients when compared to healthy controls. Neither the chemerin nor the cytokine levels correlated with parameters of nutritional status in our cohort. No statistically significant correlation was found between the serum chemerin and the inflammatory cytokines: IL-1b, IL-6, and TNFα.
CONCLUSIONS: Our results show that chemerin is not associated with the nutritional status in children with cystic fibrosis. Chemerin has no impact on the levels of IL-1b, IL-6, TNFα in CF patients. IL-1b, IL6, TNFα and also IL10 are upregulated in cystic fibrosis.

PMID: 31742967 [PubMed - as supplied by publisher]

Proof of concept for identifying cystic fibrosis from perspiration samples.

Proc Natl Acad Sci U S A. 2019 Nov 18;:

Authors: Zhou Z, Alvarez D, Milla C, Zare RN

Abstract
The gold standard for cystic fibrosis (CF) diagnosis is the determination of chloride concentration in sweat. Current testing methodology takes up to 3 h to complete and has recognized shortcomings on its diagnostic accuracy. We present an alternative method for the identification of CF by combining desorption electrospray ionization mass spectrometry and a machine-learning algorithm based on gradient boosted decision trees to analyze perspiration samples. This process takes as little as 2 min, and we determined its accuracy to be 98 ± 2% by cross-validation on analyzing 277 perspiration samples. With the introduction of statistical bootstrap, our method can provide a confidence estimate of our prediction, which helps diagnosis decision-making. We also identified important peaks by the feature selection algorithm and assigned the chemical structure of the metabolites by high-resolution and/or tandem mass spectrometry. We inspected the correlation between mild and severe CFTR gene mutation types and lipid profiles, suggesting a possible way to realize personalized medicine with this noninvasive, fast, and accurate method.

PMID: 31740593 [PubMed - as supplied by publisher]

Biofilms of Mycobacterium abscessus complex can be sensitized to antibiotics by disaggregation and oxygenation.

Antimicrob Agents Chemother. 2019 Nov 18;:

Authors: Kolpen M, Jensen PØ, Qvist T, Kragh KN, Ravnholt C, Fritz BG, Johansen UR, Bjarnsholt T, Høiby N

Abstract
Background: Pulmonary infection with the multidrug-resistant Mycobacterium abscessus complex (MABSC) is difficult to treat in individuals with cystic fibrosis (CF). MABSC grows as biofilm aggregates in CF lungs, which is known to have anaerobic niches. How aggregation and anoxic conditions affect antibiotic tolerance is not well understood.Objectives: We sought to determine whether disaggregation and oxygen availability sensitizes MABSC isolates to recommended antibiotics.Methods: We tested susceptibility of the following antibiotics amikacin, azithromycin, cefoxitin, ciprofloxacin, clarithromycin, imipenem, kanamycin, linezolid, moxifloxacin, rifampicin, tigecycline and sulfamethizole + trimethoprim for 33 isolates from 22 CF patients with MABSC infection and a reference strain. Isolates were grown in Müeller-Hinton broth with and without the disaggregating detergent Tween®80 (5%). Time-kill curves at day 1 and 3 were generated for oxic and anoxic amikacin treatment in four-fold dilutions from 2 to 512 mg L-1 Scanning electron microscopy were used to visualize aggregation patterns while confocal laser scanning microscopy and micro-respirometry were used to visualize biofilm growth patterns.Measurements and main results: Disruption of MABSC aggregates increased susceptibility to amikacin, tigecycline, kanamycin, azithromycin, imipenem, cefoxitin and clarithromycin (P<0.05, n=29-31). Oxygenation enhanced bacterial killing by amikacin in disaggregated MABSC isolates (P<0.05) by 1-6 log using 2-512 mg L-1 of amikacin.Conclusions: This study explains why current drug susceptibility testing correlates poorly to treatment outcomes. Oxic culturing of planktonic isolates in vitro does not resemble the hypoxic conditions in CF lungs. Biofilm disruption and increasing O2 availability during antibiotic therapy may be new therapeutic strategies for chronic MABSC infection.

PMID: 31740557 [PubMed - as supplied by publisher]

Deciphering the role of protein kinase CK2 in the maturation/stability of CFTR F508del.

Biochim Biophys Acta Mol Basis Dis. 2019 Nov 15;:165611

Authors: D'Amore C, Borgo C, Bosello-Travain V, Vilardell J, Salizzato V, Pinna LA, Venerando A, Salvi M

Abstract
F508del-CFTR, the most common mutation in cystic fibrosis (CF) patients, impairs CFTR trafficking to plasma membrane leading to its premature proteasomal degradation. Several post-translational modifications have been identified on CFTR with multiple roles in stability, localization and channel function, and the possibility to control the enzymes responsible of these modifications has been long considered a potential therapeutic strategy. Protein kinase CK2 has been previously suggested as an important player in regulating CFTR functions and it has been proposed as a pharmacological target in a combinatory therapy to treat CF patients. However, the real implication of CK2 in F508del-CFTR proteostasis, and in particular the hypothesis that its inhibition could be important in CF therapies, is still elusive. Here, by using immortalized cell lines, primary human cells, and knockout cell lines deprived of CK2 subunits, we do not disclose any direct correlation between F508del-CFTR proteostasis and CK2 expression/activity. Rather, our data indicate that the CK2α' catalytic subunit should be preserved rather than inhibited for F508del rescue by the correctors of class-1, such as VX-809, disclosing new important features in CF therapeutic approaches.

PMID: 31740403 [PubMed - as supplied by publisher]

The thiocyanate analog selenocyanate is a more potent antimicrobial pro-drug that also is selectively detoxified by the host.

Free Radic Biol Med. 2019 Nov 15;:

Authors: Day BJ, Bratcher PE, Chandler JD, Kilgore MB, Min E, LiPuma JJ, Hondal RJ, Nichols DP

Abstract
A hallmark of cystic fibrosis (CF) lung pathology is an increased susceptibility to pulmonary infections. Thiocyanate (-SCN) is an endogenous component of the innate immunity's peroxidase system that converts -SCN to the antimicrobial agent hypothiocyanite (HOSCN). We have previously shown that the host thioredoxin reductase (TrxR), but not the pathogen's TrxR, can selectively detoxify HOSCN thereby decreasing inflammation and oxidative stress. We tested whether the -SCN analog selenocyanate (-SeCN) shares these properties against several clinical CF bacterial isolates. We examined oxidant production from a lactoperoxidase (LPO) system using -SeCN as a potential substrate. The LPO system generated an oxidant similar in nature to HOSCN and consistent with being HOSeCN. The rate of oxidant generation using -SeCN was significantly less than seen for -SCN. An LPO system was used to generate HOSCN or HOSeCN and compared for antimicrobial activity during in situ exposure of clinical CF isolates of P. aeruginosa (PA), B. cepacia complex (BCC), and methicillin-resistant S. aureus (MRSA) obtained from CF sputum samples. Bacterial viability was assessed by colony forming units. Selective detoxification of HOSeCN was determined by comparing its metabolism by mammalian thioredoxin reductase (TrxR) to bacterial TrxR following the consumption of NADPH. We also assessed potential toxicity of equivalent HOSeCN generation, which demonstrated in situ antimicrobial activity, in human bronchial epithelial cells with a cell viability assay. The -SeCN/HOSeCN system was much more potent than -SCN/HOSCN system at killing PA, BCC and MRSA isolates. The -SeCN/HOSeCN system was more effective at killing -SCN/HOSCN resistant isolates. Mammalian TrxR selectively detoxified HOSeCN whereas the bacterial TrxR enzyme showed little activity. Human bronchial epithelial cells exposed to equivalent flux of HOSeCN that killed several CF pathogens showed no decrease in viability. -SeCN may be an effective therapeutic for the treatment of CF lung pathogens that are difficult to treat with current antibiotics.

PMID: 31740228 [PubMed - as supplied by publisher]

'Lady Windermere's counterpart? Pulmonary nontuberculous mycobacteria in men with bronchiectasis.

Diagn Microbiol Infect Dis. 2019 Oct 25;:114916

Authors: Ku JH, Ranches G, Siegel SAR, Winthrop KL

Abstract
Pulmonary nontuberculous mycobacterial (NTM) disease occurs frequently in older women, and phenotypes of men with NTM disease are largely undescribed. We conducted a case-control study of 34 men with non-cystic fibrosis pulmonary NTM disease (cases), and three male and female control groups with or without NTM disease. Cases were median 71 years of age (range 30-94) and mostly non-Hispanic white (85.3%). These men had similarly low BMI as their female NTM patient counterparts, which was lower than both healthy men (p < 0.001) and bronchiectatic men without NTM (p = 0.06). Kyphoscoliosis was also more common in cases than healthy men (p= 0.007) or bronchiectatic men without NTM (p = 0.02). Our study was the first study to our knowledge to examine demographic features and phenotypes of men with NTM disease. Larger studies are needed to ascertain whether these phenotypes are characteristic of men with NTM disease.

PMID: 31740173 [PubMed - as supplied by publisher]

Can exercise replace airway clearance techniques in cystic fibrosis? A survey of patients and healthcare professionals.

J Cyst Fibros. 2019 Nov 15;:

Authors: Rowbotham NJ, Smith SJ, Davies G, Daniels T, Elliott ZC, Gathercole K, Rayner OC, Smyth AR

Abstract
Airway clearance techniques (ACTs) are recommended in cystic fibrosis (CF) to prevent accumulation of secretions and lung infection. "Can exercise replace chest physiotherapy for people with CF?" is one of the CF community's top 10 research questions. We conducted an online survey of the CF community to gather data on current ACT use, recommendations, reported adherence levels and exercise strategies used. There were 488 respondents: 194 (40%) people with CF (pwCF), 141 (29%) family and 153 (31%) healthcare professionals (HCPs) (mostly physiotherapists). Only 10/285 (4%) of pwCF do no exercise at present and 163/303 (54%) already incorporate exercise into ACTs. ACTs were omitted by 128/267 (48%) of pwCF when they exercised. Nearly all (110/129, 93%) of HCPs currently recommend exercise to support ACTs. A trial replacing some or all ACTs with exercise, was supported by 80/110 (73%) of HCPs, with an additional 9/110 (8%) willing to consider in selected patients.

PMID: 31740105 [PubMed - as supplied by publisher]

Restless Legs Syndrome in Chronic Kidney Disease: Is Iron or Inflammatory Status To Blame?

J Clin Sleep Med. 2019 Nov 15;15(11):1629-1634

Authors: Riar SK, Greenbaum LA, Bliwise DL, Leu RM

Abstract
STUDY OBJECTIVES: Restless legs syndrome (RLS) is increased in pediatric chronic kidney disease (CKD). In adults without CKD, central nervous system iron deficiency is involved in RLS pathogenesis and a low serum ferritin levels is consequently an indication for initiation of iron therapy. However, children with CKD are at risk for iron deficiency and inflammation, which raises serum ferritin. We examined the role of iron deficiency and inflammation in RLS in pediatric CKD.
METHODS: This cross-sectional study examined RLS prevalence in three groups of pediatric patients with CKD: nontransplant, nondialysis CKD (estimated GFR < 60 mL/min/1.73 m²) (n = 27); renal transplant recipients (n = 65); and dialysis (n = 32). RLS was diagnosed using a validated questionnaire. Serum ferritin < 100 ng/mL or transferrin saturation < 20% defined iron deficiency. Serum high sensitivity C-reactive protein ≥ 1 mg/L defined inflammation.
RESULTS: Among 124 patients, RLS prevalence was 15.3%; this did not differ across groups. There was no significant difference in RLS prevalence between those with and without iron deficiency, defined by either reduced ferritin or transferrin. Median ferritin levels in patients with RLS tended to be higher than in those without RLS (51.2 versus 40.1 ng/mL; P = .08). Inflammation (elevated CRP) also did not differ significantly by RLS status (57.9% [with RLS] versus 41.2% [without RLS], P = .18).
CONCLUSIONS: Neither ferritin nor inflammation differentiated pediatric patients with CKD with and without RLS. This study suggests that the factors mediating the pathogenesis and, potentially, treatment, of RLS in pediatric CKD may be different from non-CKD populations.

PMID: 31739853 [PubMed - in process]

Sweat rate analysis of ivacaftor potentiation of CFTR in non-CF adults.

Sci Rep. 2018 11 02;8(1):16233

Authors: Kim J, Farahmand M, Dunn C, Milla CE, Horii RI, Thomas EAC, Moss RB, Wine JJ

Abstract
To determine if ivacaftor (Kalydeco) influences non-CF human CFTR function in vivo, we measured CFTR-dependent (C-sweat) and CFTR-independent (M-sweat) rates from multiple identified sweat glands in 8 non-CF adults. The two types of sweating were stimulated sequentially with intradermal injections of appropriate reagents; each gland served as its own control via alternating off-on drug tests on both arms, given at weekly intervals with 3 off and 3 on tests per subject. We compared drug effects on C-sweating stimulated by either high or low concentrations of β-adrenergic cocktail, and on methacholine-stimulated M-sweating. For each subject we measured ~700 sweat volumes from ~75 glands per arm (maximum 12 readings per gland), and sweat volumes were log-transformed for statistical analysis. T-tests derived from linear mixed models (LMMs) were more conservative than the familiar paired sample t-tests, and show that ivacaftor significantly increased C-sweating stimulated by both levels of agonist, with a larger effect in the low cocktail condition; ivacaftor did not increase M-sweat. Concurrent sweat chloride tests detected no effect of ivacaftor. We conclude that ivacaftor in vivo increases the open channel probability (PO) of WT CFTR, provided it is not already maximally stimulated.

PMID: 30389955 [PubMed - indexed for MEDLINE]