CFTR modulator therapy for cystic fibrosis caused by the rare c.3700A>G mutation.

J Cyst Fibros. 2020 Jul 14;:

Authors: Phuan PW, Haggie PM, Tan JA, Rivera AA, Finkbeiner WE, Nielson DW, Thomas MM, Janahi IA, Verkman AS

Abstract
BACKGROUND: The c.3700A>G mutation, a rare cystic fibrosis (CF)-causing CFTR mutation found mainly in the Middle East, produces full-length transcript encoding a missense mutation (I1234V-CFTR), and a cryptic splice site that deletes 6 amino acids in nucleotide binding domain 2 (I1234del-CFTR).
METHODS: FRT cell models expressing I1234V-CFTR and I1234del-CFTR were generated. We also studied an I1234del-CFTR-expressing gene-edited human bronchial (16HBE14o-) cell model, and primary cultures of nasal epithelial cells from a c.3700A>G homozygous subject. To identify improved mutation-specific CFTR modulators, high-throughput screening was done using I1234del-CFTR-expressing FRT cells. Motivated by the in vitro findings, Trikafta was tested in two c.3700A>G homozygous CF subjects.
RESULTS: FRT cells expressing full-length I1234V-CFTR had similar function to that of wildtype CFTR. I1234del-CFTR showed reduced activity, with modest activation seen with potentiators VX-770 and GLPG1837, correctors VX-809, VX-661 and VX-445, and low-temperature incubation. Screening identified novel arylsulfonyl-piperazine and spiropiperidine-quinazolinone correctors, which when used in combination with VX-445 increased current ~2-fold compared with the VX-661/VX-445 combination. The combination of VX-770 with arylsulfonamide-pyrrolopyridine, piperidine-pyridoindole or pyrazolo-quinoline potentiators gave 2-4-fold greater current than VX-770 alone. Combination potentiator (co-potentiator) efficacy was also seen in gene-edited I1234del-CFTR-expressing human bronchial epithelial cells. In two CF subjects homozygous for the c.3700A>G mutation, one subject had a 27 mmol/L decrease in sweat chloride and symptomatic improvement on Trikafta, and a second subject showed a small improvement in lung function.
CONCLUSIONS: These results support the potential benefit of CFTR modulators, including co-potentiators, for CF caused by the c.3700A>G mutation.

PMID: 32674984 [PubMed - as supplied by publisher]

K162E - A rare and uncategorized CFTR variant causing cystic fibrosis.

J Cyst Fibros. 2020 Jul 13;:

Authors: Souza EL, Ribeiro Mota L, Leite Ferreira de Lima RL, Horejs Bittencourt P, Castro Ribeiro Guedes VM, Salinas D

PMID: 32674983 [PubMed - as supplied by publisher]

Transjugular intrahepatic portosystemic shunt in non-cirrhotic portal hypertension related to cystic fibrosis in a lung transplant patient.

J Cyst Fibros. 2020 Jul 13;:

Authors: Lupi A, Barbiero G, Battistel M, Ferrarese A, Loy M, Feltracco P, Stramare R, Burra P, Senzolo M

Abstract
Liver involvement is not uncommon in patients with cystic fibrosis (CF). Even if serious complications as non-cirrhotic portal hypertension, cirrhosis and liver failure rarely occur, they are associated with impaired survival and reduced quality of life. Herein, we have reported the first case of a patient with CF and non-cirrhotic portal hypertension who underwent transjugular intrahepatic portosystemic shunt placement for recurrent variceal bleeding after bilateral lung transplantation, and we have reviewed the available literature pertaining to this field.

PMID: 32674982 [PubMed - as supplied by publisher]

Patient engagement to prioritise CF research: Inclusive or selective?

J Cyst Fibros. 2019 05;18(3):307-308

Authors: Rowbotham NJ, Smyth AR

PMID: 30982755 [PubMed - indexed for MEDLINE]

Mode of nitric oxide delivery affects antibacterial action.

ACS Biomater Sci Eng. 2020 Jan 13;6(1):433-441

Authors: Hall JR, Rouillard KR, Suchyta DJ, Brown MD, Ahonen MJR, Schoenfisc MH

Abstract
Nitric oxide (NO) is a broad-spectrum antibacterial agent, making it an attractive alternative to traditional antibiotics for treating infections. To date, a direct comparison of the antibacterial activity of gaseous NO (gNO) versus water-soluble NO-releasing biopolymers has not been reported. In this study, the bactericidal action of NO-releasing chitosan oligosaccharides was compared to gNO treatment against cystic fibrosis-relevant Gram-positive and Gram-negative bacteria. A NO exposure chamber was constructed to enable the dosing of bacteria with gNO at concentrations up to 800 ppm under both aerobic and anaerobic conditions. Bacteria viability, solution properties (i.e., pH, NO concentration), and toxicity to mammalian cells were monitored to ensure a thorough understanding of bactericidal action and reproducibility for each delivery method. The NO-releasing chitosan oligosaccharides required significantly lower NO doses relative to gNO therapy to elicit antibacterial action against Pseudomonas aeruginosa and Staphylococcus aureus under both aerobic and anaerobic conditions. Reduced NO doses required for bacteria eradication using water-soluble NO-releasing chitosan were attributed to the release of NO in solution, removing the need to transfer from gas to liquid phase and the associated long diffusion distances of gNO treatment.

PMID: 32671191 [PubMed]

Cystic fibrosis diagnosed by state newborn screening: Or is it?

SAGE Open Med Case Rep. 2020;8:2050313X20939421

Authors: Fox M, Mercier A, Savant A, Laguna TA

Abstract
Newborn screening for cystic fibrosis is universal across the United States; however, each state chooses the method by which they screen. Illinois employs a two-step process which includes the measurement of the immunoreactive trypsinogen followed by an assay designed to detect 74 of the most common genetic mutations in the cystic fibrosis transmembrane conductance regulator protein. We report the case of an infant born in Illinois with a positive cystic fibrosis newborn screening with an elevated immunoreactive trypsinogen and two genetic mutations identified (F508del/F508del). The primary care physician informed the parents their child had cystic fibrosis and referred her for a confirmatory sweat test which was negative for cystic fibrosis. Upon further investigation, the assay was found to have been set up incorrectly and repeat analysis identified the genotype F508del/F508C. This case highlights the importance of performing the confirmatory sweat test prior to making a diagnosis of cystic fibrosis.

PMID: 32670584 [PubMed]

Antibiotic Adverse Reactions in Adult Cystic Fibrosis Patients.

J Allergy Clin Immunol Pract. 2020 Jul 13;:

Authors: Anstey KM, Lee M, Dawson D, Jue V, Budzik JM, Yu M, Kleinhenz ME, Otani IM

PMID: 32673878 [PubMed - as supplied by publisher]

Distinctive lipid signatures of bronchial epithelial cells associated with cystic fibrosis drugs, including Trikafta.

JCI Insight. 2020 Jul 16;:

Authors: Liessi N, Pesce E, Braccia C, Bertozzi SM, Giraudo A, Bandiera T, Pedemonte N, Armirotti A

Abstract
Over the last years, a number of drugs have been approved for the treatment of cystic fibrosis (CF). Among them, the new Trikafta, a combination of three drugs, holds great promises to radically improve the quality of life for a large part of CF patients carrying one copy of the most frequent CFTR mutation: F508del. Currently available, disease-modifying, CF drugs work by rescuing the function of mutated CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) anion channel. Recent research work shows that membrane lipids, and the cell lipidome in general, play a significant role in the mechanism of CFTR defective trafficking and, on the other hand, in its rescue. In this paper, by using untargeted lipidomics on CFBE41o- cells, we identified distinctive changes in bronchial epithelial cell lipidome associated with treatment with the triple combination VX-661/VX-445/VX-770 (drug name: Trikafta) and other CF drugs. Particularly interesting is the reduction of ceramide levels, known molecular players in the induction of apoptosis, that appears to be associated with a decrease in cell susceptibility to undergo apoptosis. This evidence could account for additional beneficial role of the triple combination on CF phenotypes.

PMID: 32673287 [PubMed - as supplied by publisher]

Users' Experiences of a Mobile Health Self-Management Approach for the Treatment of Cystic Fibrosis: Mixed Methods Study.

JMIR Mhealth Uhealth. 2020 Jul 08;8(7):e15896

Authors: Floch J, Vilarinho T, Zettl A, Ibanez-Sanchez G, Calvo-Lerma J, Stav E, Haro PH, Aalberg AL, Fides-Valero A, Bayo Montón JL

Abstract
BACKGROUND: Despite a large number of clinical trials aiming at evaluating the digital self-management of chronic diseases, there is little discussion about users' experiences with digital approaches. However, a good user experience is a critical factor for technology adoption. Understanding users' experiences can inform the design of approaches toward increased motivation for digital self-management.
OBJECTIVE: This study aimed to evaluate the self-management of cystic fibrosis (CF) with a focus on gastrointestinal concerns and the care of young patients. Following a user-centered design approach, we developed a self-management app for patients and parents and a web tool for health care professionals (HCPs). To evaluate the proposed solutions, a 6-month clinical trial was conducted in 6 European CF competence centers. This paper analyzes the user acceptance of the technology and the benefits and disadvantages perceived by the trial participants.
METHODS: A mixed methods approach was applied. Data were collected through 41 semistructured qualitative interviews of patients, parents, and HCPs involved in the clinical trial. In addition, data were collected through questionnaires embedded in the self-management app.
RESULTS: Support for enzyme dose calculation and nutrition management was found to be particularly useful. Patients and parents rapidly strengthened their knowledge about the treatment and increased their self-efficacy. Reported benefits include reduced occurrence of symptoms and enhanced quality of life. Patients and parents had different skills, requiring follow-up by HCPs in an introductory phase. HCPs valued obtaining precise information about the patients, allowing for more personalized advice. However, the tight follow-up of several patients led to an increased workload. Over time, as patient self-efficacy increased, patient motivation for using the app decreased and the quality of the reported data was reduced.
CONCLUSIONS: Self-management enfolds a collaboration between patients and HCPs. To be successful, a self-management approach should be accepted by both parties. Through understanding behaviors and experiences, this study defines recommendations for a complex case-the demanding treatment of CF. We identify target patient groups and situations for which the app is most beneficial and suggest focusing on these rather than motivating for regular app usage over a long time. We also advise the personalized supervision of patients during the introduction of the approach. Finally, we propose to develop guidance for HCPs to facilitate changes in practice. As personalization and technology literacy are factors found to influence the acceptance of digital self-management of other chronic diseases, it is relevant to consider the proposed recommendations beyond the case of CF.

PMID: 32673237 [PubMed - as supplied by publisher]

Dietary interventions for phenylketonuria.

Cochrane Database Syst Rev. 2020 Jul 16;7:CD001304

Authors: Jameson E, Remmington T

Abstract
BACKGROUND: Phenylketonuria is an inherited disease treated with dietary restriction of the amino acid phenylalanine. The diet is initiated in the neonatal period to prevent learning disability; however, it is restrictive and can be difficult to follow. Whether the diet can be relaxed or discontinued during adolescence or should be continued for life remains a controversial issue, which we aim to address in this review. This is an updated version of a previously published review.
OBJECTIVES: To assess the effects of a low-phenylalanine diet commenced early in life for people with phenylketonuria. To assess the possible effects of relaxation or termination of the diet on intelligence, neuropsychological outcomes and mortality, growth, nutritional status, eating behaviour and quality of life.
SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearches of relevant journals and abstract books of conference proceedings. Most recent search of the Inborn Errors of Metabolism Trials Register: 30 April 2020.
SELECTION CRITERIA: All randomised or quasi-randomised controlled trials comparing a low-phenylalanine diet to relaxation or termination of dietary restrictions in people with phenylketonuria.
DATA COLLECTION AND ANALYSIS: Two authors independently assessed study eligibility and methodological quality, and subsequently extracted the data.
MAIN RESULTS: We included four studies in this review (251 participants), and found few significant differences between treatment and comparison groups for the outcomes of interest. Blood phenylalanine levels were significantly lower in participants with phenylketonuria following a low-phenylalanine diet compared to those on a less restricted diet, mean difference (MD) at three months -698.67 (95% confidence interval (CI) -869.44 to -527.89). Intelligence quotient was significantly higher in participants who continued the diet than in those who stopped the diet, MD after 12 months 5.00 (95% CI 0.40 to 9.60). However, these results came from a single study.
AUTHORS' CONCLUSIONS: The results of non-randomised studies have concluded that a low-phenylalanine diet is effective in reducing blood phenylalanine levels and improving intelligence quotient and neuropsychological outcomes. We were unable to find any randomised controlled studies that have assessed the effect of a low-phenylalanine diet versus no diet from diagnosis. In view of evidence from non-randomised studies, such a study would be unethical and it is recommended that low-phenylalanine diet should be commenced at the time of diagnosis. There is uncertainty about the precise level of phenylalanine restriction and when, if ever, the diet should be relaxed. This should be addressed by randomised controlled studies; however, no new studies are expected in this area so we do not plan to update this review.

PMID: 32672365 [PubMed - in process]

Antibiotic adjuvant therapy for pulmonary infection in cystic fibrosis.

Cochrane Database Syst Rev. 2020 Jul 16;7:CD008037

Authors: Hurley MN, Smith S, Forrester DL, Smyth AR

Abstract
BACKGROUND: Cystic fibrosis is a multi-system disease characterised by the production of thick secretions causing recurrent pulmonary infection, often with unusual bacteria. This leads to lung destruction and eventually death through respiratory failure. There are no antibiotics in development that exert a new mode of action and many of the current antibiotics are ineffective in eradicating the bacteria once chronic infection is established. Antibiotic adjuvants - therapies that act by rendering the organism more susceptible to attack by antibiotics or the host immune system, by rendering it less virulent or killing it by other means, would be a significant therapeutic advance. This is an update of a previously published review.
OBJECTIVES: To determine if antibiotic adjuvants improve clinical and microbiological outcome of pulmonary infection in people with cystic fibrosis.
SEARCH METHODS: We searched the Cystic Fibrosis Trials Register which is compiled from database searches, hand searches of appropriate journals and conference proceedings. Date of most recent search: 16 January 2020. We also searched MEDLINE (all years) on 14 February 2019 and ongoing trials registers on 06 April 2020.
SELECTION CRITERIA: Randomised controlled trials and quasi-randomised controlled trials of a therapy exerting an antibiotic adjuvant mechanism of action compared to placebo or no therapy for people with cystic fibrosis.
DATA COLLECTION AND ANALYSIS: Two of the authors independently assessed and extracted data from identified trials.
MAIN RESULTS: We identified 42 trials of which eight (350 participants) that examined antibiotic adjuvant therapies are included. Two further trials are ongoing and five are awaiting classification. The included trials assessed β-carotene (one trial, 24 participants), garlic (one trial, 34 participants), KB001-A (a monoclonal antibody) (two trials, 196 participants), nitric oxide (two trials, 30 participants) and zinc supplementation (two trials, 66 participants). The zinc trials recruited children only, whereas the remaining trials recruited both adults and children. Three trials were located in Europe, one in Asia and four in the USA. Three of the interventions measured our primary outcome of pulmonary exacerbations (β-carotene, mean difference (MD) -8.00 (95% confidence interval (CI) -18.78 to 2.78); KB001-A, risk ratio (RR) 0.25 (95% CI 0.03 to 2.40); zinc supplementation, RR 1.85 (95% CI 0.65 to 5.26). β-carotene and KB001-A may make little or no difference to the number of exacerbations experienced (low-quality evidence); whereas, given the moderate-quality evidence we found that zinc probably makes no difference to this outcome. Respiratory function was measured in all of the included trials. β-carotene and nitric oxide may make little or no difference to forced expiratory volume in one second (FEV1) (low-quality evidence), whilst garlic probably makes little or no difference to FEV1 (moderate-quality evidence). It is uncertain whether zinc or KB001-A improve FEV1 as the certainty of this evidence is very low. Few adverse events were seen across all of the different interventions and the adverse events that were reported were mild or not treatment-related (quality of the evidence ranged from very low to moderate). One of the trials (169 participants) comparing KB001-A and placebo, reported on the time to the next course of antibiotics; results showed there is probably no difference between groups, HR 1.00 (95% CI 0.69 to 1.45) (moderate-quality evidence). Quality of life was only reported in the two KB001-A trials, which demonstrated that there may be little or no difference between KB001-A and placebo (low-quality evidence). Sputum microbiology was measured and reported for the trials of KB001-A and nitric oxide (four trials). There was very low-quality evidence of a numerical reduction in Pseudomonas aeruginosa density with KB001-A, but it was not significant. The two trials looking at the effects of nitric oxide reported significant reductions in Staphylococcus aureus and near-significant reductions in Pseudomonas aeruginosa, but the quality of this evidence is again very low.
AUTHORS' CONCLUSIONS: We could not identify an antibiotic adjuvant therapy that we could recommend for treating of lung infection in people with cystic fibrosis. The emergence of increasingly resistant bacteria makes the reliance on antibiotics alone challenging for cystic fibrosis teams. There is a need to explore alternative strategies, such as the use of adjuvant therapies. Further research is required to provide future therapeutic options.

PMID: 32671834 [PubMed - in process]

Autophagy and Others Respiratory Diseases.

Adv Exp Med Biol. 2020;1207:585-597

Authors: Lv X, Li K, Hu Z

Abstract
Besides COPD, pulmonary fibrosis, and asthma, autophagy also participates in the development of many other respiratory diseases. Cystic fibrosis is an innate lung disease. Unlike idiopathic pulmonary fibrosis, cystic fibrosis has unique pathogenesis. Autophagy is an essential biological mechanism for the removal of misfolded proteins and damaged organelles in cells. Abnormal autophagy activity is involved in the pathogenesis of cystic fibrosis. Various studies have demonstrated that abnormalities or impaired autophagy are associated with cardiovascular diseases including pulmonary vascular disease. Autophagy plays a key role in maintaining normal vascular biological functions and vascular cell tissue homeostasis, and also plays an important role in the pathogenesis of various vascular diseases. For example, recent studies have found that autophagy participates in the occurrence and development of pulmonary hypertension. In addition, autophagy plays a central role in both innate and adaptive immune responses in immune cells or other cells with immune function. Thus, autophagy is the important cellular biological mechanism which causes cell fighting against pathogenic microorganisms including viruses, bacteria, and parasites. In this chapter, we discuss the work related to autophagy and other lung diseases.

PMID: 32671777 [PubMed - in process]

DNA Methylation Epigenetically Regulates Gene Expression in Burkholderia cenocepacia and Controls Biofilm Formation, Cell Aggregation, and Motility.

mSphere. 2020 Jul 15;5(4):

Authors: Vandenbussche I, Sass A, Pinto-Carbó M, Mannweiler O, Eberl L, Coenye T

Abstract
Respiratory tract infections by the opportunistic pathogen Burkholderia cenocepacia often lead to severe lung damage in cystic fibrosis (CF) patients. New insights in how to tackle these infections might emerge from the field of epigenetics, as DNA methylation is an important regulator of gene expression. The present study focused on two DNA methyltransferases (MTases) in B. cenocepacia strains J2315 and K56-2 and their role in regulating gene expression. In silico predicted DNA MTase genes BCAL3494 and BCAM0992 were deleted in both strains, and the phenotypes of the resulting deletion mutants were studied: deletion mutant ΔBCAL3494 showed changes in biofilm structure and cell aggregation, while ΔBCAM0992 was less motile. B. cenocepacia wild-type cultures treated with sinefungin, a known DNA MTase inhibitor, exhibited the same phenotype as DNA MTase deletion mutants. Single-molecule real-time sequencing was used to characterize the methylome of B. cenocepacia, including methylation at the origin of replication, and motifs CACAG and GTWWAC were identified as targets of BCAL3494 and BCAM0992, respectively. All genes with methylated motifs in their putative promoter region were identified, and qPCR experiments showed an upregulation of several genes, including biofilm- and motility-related genes, in MTase deletion mutants with unmethylated motifs, explaining the observed phenotypes in these mutants. In summary, our data confirm that DNA methylation plays an important role in regulating the expression of B. cenocepacia genes involved in biofilm formation, cell aggregation, and motility.IMPORTANCE CF patients diagnosed with Burkholderia cenocepacia infections often experience rapid deterioration of lung function, known as cepacia syndrome. B. cenocepacia has a large multireplicon genome, and much remains to be learned about regulation of gene expression in this organism. From studies in other (model) organisms, it is known that epigenetic changes through DNA methylation play an important role in this regulation. The identification of B. cenocepacia genes of which the expression is regulated by DNA methylation and identification of the regulatory systems involved in this methylation are likely to advance the biological understanding of B. cenocepacia cell adaptation via epigenetic regulation. In time, this might lead to novel approaches to tackle B. cenocepacia infections in CF patients.

PMID: 32669472 [PubMed - in process]

Dispersal of Epithelium-Associated Pseudomonas aeruginosa Biofilms.

mSphere. 2020 Jul 15;5(4):

Authors: Zemke AC, D'Amico EJ, Snell EC, Torres AM, Kasturiarachi N, Bomberger JM

Abstract
Pseudomonas aeruginosa grows in highly antibiotic-tolerant biofilms during chronic airway infections. Dispersal of bacteria from biofilms may restore antibiotic susceptibility or improve host clearance. We describe models to study biofilm dispersal in the nutritionally complex environment of the human airway. P. aeruginosa was cocultured in the apical surface of airway epithelial cells (AECs) in a perfusion chamber. Dispersal, triggered by sodium nitrite, a nitric oxide (NO) donor, was tracked by live cell microscopy. Next, a static model was developed in which biofilms were grown on polarized AECs without flow. We observed that NO-triggered biofilm dispersal was an energy-dependent process. From the existing literature, NO-mediated biofilm dispersal is regulated by DipA, NbdA, RbdA, and MucR. Interestingly, altered signaling pathways appear to be used in this model, as deletion of these genes failed to block NO-induced biofilm dispersal. Similar results were observed using biofilms grown in an abiotic model on glass with iron-supplemented cell culture medium. In cystic fibrosis, airway mucus contributes to the growth environment, and a wide range of bacterial phenotypes are observed; therefore, we tested biofilm dispersal in a panel of late cystic fibrosis clinical isolates cocultured in the mucus overlying primary human AECs. Finally, we examined dispersal in combination with the clinically used antibiotics ciprofloxacin, aztreonam and tobramycin. In summary, we have validated models to study biofilm dispersal in environments that recapitulate key features of the airway and identified combinations of currently used antibiotics that may enhance the therapeutic effect of biofilm dispersal.IMPORTANCE During chronic lung infections, Pseudomonas aeruginosa grows in highly antibiotic-tolerant communities called biofilms that are difficult for the host to clear. We have developed models for studying P. aeruginosa biofilm dispersal in environments that replicate key features of the airway. We found that mechanisms of biofilm dispersal in these models may employ alternative or additional signaling mechanisms, highlighting the importance of the growth environment in dispersal events. We have adapted the models to accommodate apical fluid flow, bacterial clinical isolates, antibiotics, and primary human airway epithelial cells, all of which are relevant to understanding bacterial behaviors in the context of human disease. We also examined dispersal agents in combination with commonly used antipseudomonal antibiotics and saw improved clearance when nitrite was combined with the antibiotic aztreonam.

PMID: 32669459 [PubMed - in process]

A high prevalence of genetic polymorphisms in idiopathic and alcohol-associated chronic pancreatitis patients in Ireland.

HPB (Oxford). 2020 Jul 12;:

Authors: Ní Chonchubhair HM, Duggan SN, Egan SM, Kenyon M, O'Toole D, McManus R, Conlon KC

Abstract
BACKGROUND: Individual genetic architecture is considered central to susceptibility and progression of disease in chronic pancreatitis. The study aimed to evaluate the presence of common pancreatic gene mutations in a defined cohort of idiopathic and alcohol-induced chronic pancreatitis patients in Ireland.
METHODS: The study comprised patients with idiopathic and alcohol-induced chronic pancreatitis and historic controls. Variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, cationic trypsinogen (PRSS1) gene and serine protease inhibitor kazal type-1 (SPINK1) gene, were assessed by Taqman© genotyping assay.
RESULTS: Of n = 126 patients and n = 167 controls, mutations were detected in 23 (20%) and in 10 (6%) respectively (P < 0.001). The majority of mutations found were in the SPINK1 gene variant N34S (13%) which increased disease risk almost six-fold (OR 5.9). Neither CFTR severe mutation (F508del) (P = 0.649) nor mild variant (R117H) (P = 0.327) were over-represented amongst patients compared to control subjects. PRSS1 variants were not detected in either patient or control subjects.
CONCLUSION: There was a significant prevalence of chronic pancreatitis-associated gene mutations in this well-phenotyped cohort. In patients with alcohol-related or idiopathic chronic pancreatitis, the possibility of genetic mutations in the SPINK 1 gene should be considered as a contributing aetiology factor.

PMID: 32669225 [PubMed - as supplied by publisher]

A four week trial of hypertonic saline in children with mild cystic fibrosis lung disease: Effect on mucociliary clearance and clinical outcomes.

J Cyst Fibros. 2020 Jul 12;:

Authors: Donaldson SH, Danielle Samulski T, LaFave C, Zeman K, Wu J, Trimble A, Ceppe A, Bennett WD, Davis SD

Abstract
BACKGROUND: Hypertonic saline (HS) is commonly prescribed for children with cystic fibrosis (CF) despite the absence of strong data indicating clinical efficacy in a population with mild lung disease. We hypothesized that HS treatment would result in a sustained improvement in mucociliary clearance (MCC) in children with CF who had minimal lung disease, thus providing evidence for a biologically relevant effect that also may be associated with clinical improvements.
METHODS: We performed a randomized, placebo controlled, double blind study of 6% versus 0.12% sodium chloride, delivered three-times daily with an eFlow nebulizer for 4 weeks. MCC was measured using gamma scintigraphy at baseline, 2-hours after the first study treatment, and ~12-hours after the final dose (at day 28). Spirometry, respiratory symptoms (CFQ-R), and safety were also assessed.
RESULTS: Study treatments were generally well tolerated and safe. HS (6% sodium chloride) resulted in a significant, sustained improvement from baseline in whole lung clearance after 4 weeks of therapy (p = 0.014), despite absence of a prolonged single-dose effect after the initial dose. This sustained change (12 hrs after prior dose) was significantly greater when compared to placebo (0.12% sodium chloride) treatment (p = 0.016). Improvements in spirometry with HS did not reach statistical significance but correlated with MCC changes.
CONCLUSIONS: The observed sustained improvement in MCC with HS suggests that this treatment may yield health benefits, even in relatively mildly affected children with CF. Highlighting this physiologic finding is important due to the lack of meaningful, validated endpoints in this population.

PMID: 32669217 [PubMed - as supplied by publisher]

Positive clinical response to ivacaftor treatment in an individual with the CFTR genotype F508del/V456A.

J Cyst Fibros. 2019 03;18(2):e9-e10

Authors: Bratcher PE, Hunt KC, Pickard K, Taylor-Cousar JL

PMID: 30348612 [PubMed - indexed for MEDLINE]

R560S: A class II CFTR mutation that is not rescued by current modulators.

J Cyst Fibros. 2019 03;18(2):182-189

Authors: Awatade NT, Ramalho S, Silva IAL, Felício V, Botelho HM, de Poel E, Vonk A, Beekman JM, Farinha CM, Amaral MD

Abstract
BACKGROUND: New therapies modulating defective CFTR have started to hit the clinic and others are in trial or under development. The endeavour of drug discovery for CFTR protein rescue is however difficult one since over 2000 mutations have been reported. For most of these, especially the rare ones, the associated defects, the respective functional class and their responsiveness to available modulators are still unknown. Our aim here was to characterize the rare R560S mutation using patient-derived materials (rectal biopsies and intestinal organoids) from one CF individual homozygous for this mutation, in parallel with cellular models expressing R560S-CFTR and to assess the functional and biochemical responses to CFTR modulators.
METHODS: Intestinal organoids were prepared from rectal biopsies and analysed by RT-PCR (to assess CFTR mRNA), by Western blot (to assess CFTR protein) and by forskolin-induced swelling (FIS) assay. A novel cell line expressing R560S-CFTR was generated by stably transducing the CFBE parental cell line and used to assess R560S-CFTR processing and function. Both intestinal organoids and the cellular model were used to assess efficacy of CFTR modulators in rescuing this mutation.
RESULTS: Our results show that: R560S does not affect CFTR mRNA splicing; R560S affects CFTR protein processing, totally abrogating the production of its mature form; R560S-CFTR evidences no function as a Cl- channel; and none of the modulators tested rescued R560S-CFTR processing or function.
CONCLUSION: Altogether, these results indicate that R560S is a class II mutation. However, unlike F508del, it cannot be rescued by any of the CFTR modulators tested.

PMID: 30030066 [PubMed - indexed for MEDLINE]

Hypoglycemia and Islet Dysfunction following Oral Glucose Tolerance Testing in Pancreatic Insufficient Cystic Fibrosis.

J Clin Endocrinol Metab. 2020 Jul 16;:

Authors: Kilberg MJ, Harris C, Sheikh S, Stefanovski D, Cuchel M, Kubrak C, Hadjiliadis D, Rubenstein RC, Rickels MR, Kelly A

Abstract
CONTEXT: Oral glucose tolerance test (OGTT)-related hypoglycemia is common in pancreatic insufficient cystic fibrosis (PI-CF), but its mechanistic underpinnings are yet to be established.
OBJECTIVE: To delineate the mechanism(s) underlying OGTT-related hypoglycemia.
DESIGN AND SETTING: We performed 180-minute OGTT with frequent blood sampling in adolescents and young adults with PI-CF and compared results to those from a historical healthy control group. Hypoglycemia (Hypo[+]) was defined as plasma glucose <65 mg/dL. We hypothesized that CF-Hypo[+] would demonstrate impaired early-phase insulin secretion and persistent late insulin effect compared to Control-Hypo[+], and explored the contextual counterregulatory response.
MAIN OUTCOME MEASURE: OGTT 1-hour and nadir glucose, insulin, C-peptide, and insulin secretory rate (ISR) incremental areas-under-the-curve (AUC) between 0-30 min (early) and 120-180 min (late), and Δglucagon120-180min and ΔFree Fatty Acids(FFA)120-180min were compared between CF- and Control-Hypo[+].
RESULTS: Hypoglycemia occurred in 15/23 (65%) CF (43% female, age 24.8 [14.6-30.6] years) and 8/15 (55%) controls (33% female, age 26 [21-38] years). CF-Hypo[+] vs Control-Hypo[+] had higher 1-hour glucose (197±49 vs 139±53 mg/dL, p=0.05) and lower nadir glucose (48±7 vs 59±4 mg/dL, p<0.01), while insulin-, C-peptide-,and ISR-AUC0-30 min were lower and insulin- and C-peptide-AUC120-180min were higher (p<0.05). CF-Hypo[+] had lower Δglucagon120-180min and ΔFFA120-180min compared to Control-Hypo[+] (p<0.01).
CONCLUSIONS: OGTT-related hypoglycemia in PI-CF is associated with elevated 1-hour glucose, impaired early-phase insulin secretion, higher late insulin exposure, and less increase in glucagon and FFA. These data suggest that hypoglycemia in CF is a manifestation of islet dysfunction including an impaired counterregulatory response.

PMID: 32668452 [PubMed - as supplied by publisher]

SARS-CoV-2 (COVID-19) and Cystic Fibrosis.

Am J Physiol Lung Cell Mol Physiol. 2020 Jul 15;:

Authors: Stanton BA, Hampton TH, Ashare A

Abstract
Cystic Fibrosis (CF) is a genetic disease caused by mutations in the CFTR gene. Although viral respiratory tract infections are, in general, more severe in patients with CF compared to the general population, a small number of studies indicate that SARS-CoV-2 does not cause a worse infection in CF. This is surprising since comorbidities including preexisting lung disease have been reported to be associated with worse outcomes in SARS-CoV-2 infections. Several recent studies provide insight into why SARS-CoV-2 may not produce more severe outcomes in CF. First, ACE and ACE2, genes that play key roles in SARS-CoV-2 infection have some variants that are predicted to reduce the severity of SARS-CoV-2 infection. Second, mRNA for ACE2 is elevated and the mRNA for TMPRSS2, a serine protease, is decreased in CF airway epithelial cells. Increased ACE2 is predicted to enhance SARS-CoV-2 binding to cells, but would increase conversion of angiotensin II, which is proinflammatory, to angiotensin-1-7, which is anti-inflammatory. Thus, increased ACE2 would reduce inflammation and lung damage due to SARS-CoV-2. Moreover, decreased TMPRSS2 would reduce SARS-CoV-2 entry into airway epithelial cells. Second, many CF patients are treated with azithromycin, which suppresses viral infection and lung inflammation, and inhibits the activity of furin, a serine protease. Finally, the CF lung contains high levels of serine protease inhibitors including ecotin and SERPINB1, which are predicted to reduce the ability of TMPRSS2 to facilitate SARS-CoV-2 entry into airway epithelial cells. Thus, a variety of factors may mitigate the severity of SARS-CoV-2 in CF.

PMID: 32668165 [PubMed - as supplied by publisher]