Origins of Cystic Fibrosis Lung Disease

Stoltz, David A.; Meyerholz, David K.; Welsh, Michael J.

doi:10.1056/nejmra1300109

Cited by 583 publications

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“…Representative traces for each compound tested are shown in Figure 2e. Three of the agents (12)(13)(14) were also tested using a variation of the protocol in which the POPC was omitted and compounds were added to the cells as solutions in DMSO. The results are given in Table 1 The contrast between 7 and 13 is especially striking -in LUVs their performance is almost identical, yet in the cells they are at opposite ends of the spectrum.…”

Section: Resultsmentioning

confidence: 99%

“…The application of anionophores in CF treatment requires that they should be effective in epithelia (for example the bronchial epithelia in the lungs of CF patients). 13 As a further test of their potential, we investigated whether the anionophores could mediate Cl − currents in epithelia using the Ussing chamber technique 18 . YFP-FRT epithelial cells were grown on permeable filter supports to form polarised epithelia with a high electrical resistance.…”

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confidence: 99%

“…A particular hope is that anionophores might be used to replace the activity of endogenous anion channels which are missing or defective 11,2 . Such deficiencies underlie a number of medical conditions including Best disease, Startle disease, Bartter's syndrome and, most notably, the widespread lifeshortening genetic disease cystic fibrosis (CF) 12,13 .If anionophores are to be used to treat these "channelopathies", it must be shown that they can be delivered to cells in sufficient quantities to produce substantial effects, of the same order of magnitude as endogenous anion channels, and that these quantities are not toxic to the cells. However, while a wide variety of anionophores have been studied in synthetic membranes (principally large unilamellar vesicles, or LUVs), the range of systems subjected to biological investigations is still quite limited.…”

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Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia

Valkenier

Judd³

et al. 2015

Nature Chem

151

160

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The transport of anions across cell membranes has become an important goal for supramolecular chemistry [1][2][3][4] . It is well-known that cation carriers (cationophores) can serve as antibiotics and toxins 5,6 , and it seems likely that anion carriers might also show useful biological activity. However, suitable anionophores have only recently become available 7-10 , and the nature of their biological effects is still in question. A particular hope is that anionophores might be used to replace the activity of endogenous anion channels which are missing or defective 11,2 . Such deficiencies underlie a number of medical conditions including Best disease, Startle disease, Bartter's syndrome and, most notably, the widespread lifeshortening genetic disease cystic fibrosis (CF) 12,13 .If anionophores are to be used to treat these "channelopathies", it must be shown that they can be delivered to cells in sufficient quantities to produce substantial effects, of the same order of magnitude as endogenous anion channels, and that these quantities are not toxic to the cells. However, while a wide variety of anionophores have been studied in synthetic membranes (principally large unilamellar vesicles, or LUVs), the range of systems subjected to biological investigations is still quite limited. Moreover, from the point of view of CF treatment, the results thus far have been mixed. On the positive side, a few systems have been tested in whole cells, epithelia or (in one case) genetically modified mice 14 , using electrophysiological methods such as patch-clamp and Ussing chamber, and shown to induce anion conduction without obvious toxic effects. These anionophores include synthetic 3 peptides conceptually related to natural anion channels 11,[15][16][17] , as well as the steroid-based system 1 from the authors' laboratory 18 , and other small organic molecules 14,19,20 .Less encouragingly, a number of molecules showing anion transport in LUVs have tested positive for anti-cancer cytotoxicity (potentially valuable, but incompatible with CF treatment) 8,[21][22][23][24][25] . Many of these systems, including the well-studied prodigiosin 2 26 , transport protons as well as anions 8,[21][22][23] . Intracellular acidification can lead to apoptosis 26 , so in these cases proton transport could underlie toxicity. On the other hand, a recent study on calixpyrroles 3 suggested that anion transport as such could be cytotoxic 25 . As the transport activity of 3 was only weak, this raises the concern that powerful anionophores might be highly toxic and thus unsuitable for CF treatment. Thus far the only biological testing of these "1,5-diaxial" systems has been the early study on 1, referred to above 18 . The assay involved the application of 1 to the apical membrane of oriented Madin Darby canine kidney cell (MDCK) epithelia, mounted in an Ussing chamber, and measurement of the resulting electrical current caused by Cl − transport. The methodology is well-established, but not so convenient for screening large numbers of compounds.Mor...

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Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia

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Judd³

et al. 2015

Nature Chem

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“…Although CF pulmonary decline is attributed frequently to progressive mucus plugging and bronchiectasis (30)(31)(32)(33)(34)(35), peribronchiolar stenosis has been reported ORIGINAL RESEARCH frequently in "older" patients with CF (36)(37)(38). Lesions in our biopsied adolescent patients reflect similarities to findings in end-stage disease, suggesting the important contribution of distal airway limitation to respiratory decline.…”

Section: Discussionmentioning

confidence: 66%

Constrictive Bronchiolitis in Cystic Fibrosis Adolescents with Refractory Pulmonary Decline

et al. 2016

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Rationale: Refractory lung function decline in association with recurrent pulmonary exacerbations is a common, yet poorly explained finding in cystic fibrosis (CF). To investigate the histopathologic mechanisms of pulmonary deterioration during adolescence and early adulthood, we reviewed clinicallyindicated lung biopsy specimens obtained during a period of persistent decline.Objectives: To determine if peribronchiolar remodeling is prominent in lung biopsy specimens obtained in adolescents with CF refractory to conventional therapy.Methods: Six adolescents with CF (mean age, 16.2 y; mean FEV 1 , 52% predicted at biopsy) with significant pulmonary deterioration over 12-24 months (mean FEV 1 decline of 14% predicted/year) despite aggressive intervention underwent computed tomography imaging and ultimately lung biopsy to aid clinical management. In addition to routine clinical evaluation, histopathologic investigation included staining for transforming growth factor-b (TGF-b, a genetic modifier of CF lung disease), collagen deposition (a marker of fibrosis), elastin (to evaluate for bronchiectasis), and a-smooth muscle actin (to identify myofibroblasts).

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Cystic Fibrosis

Ong

Ramsey

2023

JAMA

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ImportanceCystic fibrosis, a genetic disorder defined by variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, affects more than 30 000 individuals in the US and approximately 89 000 worldwide. Absent or decreased function of the CFTR protein is associated with multiorgan dysfunction and shortened life expectancy.ObservationsCFTR is an anion channel in the apical membrane of epithelial cells. Loss of function leads to obstructed exocrine glands. Of people with cystic fibrosis in the US, approximately 85.5% have the gene variant F508del. Manifestations of cystic fibrosis in patients with the F508del gene variant begin in infancy with steatorrhea, poor weight gain, and respiratory symptoms (coughing, wheezing). As people with cystic fibrosis age, chronic respiratory bacterial infections cause loss of lung function and bronchiectasis. With the availability of universal newborn screening in multiple countries including the US, many people with cystic fibrosis are asymptomatic at diagnosis. With multidisciplinary care teams that included dietitians, respiratory therapists, and social workers, treatment of cystic fibrosis can slow disease progression. Median survival has improved from 36.3 years (95% CI, 35.1-37.9) in 2006 to 53.1 years (95% CI, 51.6-54.7) in 2021. Pulmonary therapies for patients with cystic fibrosis consist of mucolytics (eg, dornase alfa), anti-inflammatories (eg, azithromycin), and antibiotics (such as tobramycin delivered by a nebulizer). Four small molecular therapies, termed CFTR modulators, that facilitate CFTR production and/or function have received regulatory approval. Examples are ivacaftor and elexacaftor-tezacaftor-ivacaftor. For example, in patients with 1 F508del variant, the combination of ivacaftor, tezacaftor, and elexacaftor improved lung function from −0.2% in the placebo group to 13.6% (difference, 13.8%; 95% CI, 12.1%-15.4%) and decreased the annualized estimated rate of pulmonary exacerbations from 0.98 to 0.37 (rate ratio, 0.37; 95% CI, 0.25-0.55). Improved respiratory function and symptoms have lasted up to 144 weeks in postapproval observational studies. An additional 177 variants are eligible for treatment with the elexacaftor-tezacaftor-ivacaftor combination.ConclusionCystic fibrosis affects approximately 89 000 people worldwide and is associated with a spectrum of disease related to exocrine dysfunction, including chronic respiratory bacterial infections and reduced life expectancy. First-line pulmonary therapies consist of mucolytics, anti-inflammatories, and antibiotics, and approximately 90% of people with cystic fibrosis who are 2 years or older may benefit from a combination of ivacaftor, tezacaftor, and elexacaftor.

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Origins of Cystic Fibrosis Lung Disease

Cited by 583 publications

References 73 publications

Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia

Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia

Constrictive Bronchiolitis in Cystic Fibrosis Adolescents with Refractory Pulmonary Decline

Cystic Fibrosis

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