Cell Mol Life Sci. 2022 Sep;79(9):503. doi: 10.1007/s00018-022-04528-3. Epub 2022 Sep 1.

ABSTRACT

Early recognition and enhanced degradation of misfolded proteins by the endoplasmic reticulum (ER) quality control and ER-associated degradation (ERAD) cause defective protein secretion and membrane targeting, as exemplified for Z-alpha-1-antitrypsin (Z-A1AT), responsible for alpha-1-antitrypsin deficiency (A1ATD) and F508del-CFTR (cystic fibrosis transmembrane conductance regulator) responsible for cystic fibrosis (CF). Prompted by our previous observation that decreasing Keratin 8 (K8) expression increased trafficking of F508del-CFTR to the plasma membrane, we investigated whether K8 impacts trafficking of soluble misfolded Z-A1AT protein. The subsequent goal of this study was to elucidate the mechanism underlying the K8-dependent regulation of protein trafficking, focusing on the ERAD pathway. The results show that diminishing K8 concentration in HeLa cells enhances secretion of both Z-A1AT and wild-type (WT) A1AT with a 13-fold and fourfold increase, respectively. K8 down-regulation triggers ER failure and cellular apoptosis when ER stress is jointly elicited by conditional expression of the µs heavy chains, as previously shown for Hrd1 knock-out. Simultaneous K8 silencing and Hrd1 knock-out did not show any synergistic effect, consistent with K8 acting in the Hrd1-governed ERAD step. Fractionation and co-immunoprecipitation experiments reveal that K8 is recruited to ERAD complexes containing Derlin2, Sel1 and Hrd1 proteins upon expression of Z/WT-A1AT and F508del-CFTR. Treatment of the cells with c407, a small molecule inhibiting K8 interaction, decreases K8 and Derlin2 recruitment to high-order ERAD complexes. This was associated with increased Z-A1AT secretion in both HeLa and Z-homozygous A1ATD patients' respiratory cells. Overall, we provide evidence that K8 acts as an ERAD modulator. It may play a scaffolding protein role for early-stage ERAD complexes, regulating Hrd1-governed retrotranslocation initiation/ubiquitination processes. Targeting K8-containing ERAD complexes is an attractive strategy for the pharmacotherapy of A1ATD.

PMID:36045259 | DOI:10.1007/s00018-022-04528-3

J Cyst Fibros. 2022 Aug 28:S1569-1993(22)00647-6. doi: 10.1016/j.jcf.2022.08.010. Online ahead of print.

ABSTRACT

BACKGROUND: Long-term treatment with inhaled antibiotics is recommended for people with cystic fibrosis (pwCF) chronically infected with Pseudomonas aeruginosa (PA). However, pwCF without chronic PA infection are also commonly treated with inhaled antibiotics. Using data from the European Cystic Fibrosis Patient Registry (ECFSPR) we aimed to determine the prevalence and factors associated with inhaled antibiotic treatment in pwCF without chronic PA infection, and long-term outcomes with inhaled antibiotics use.

METHODS: The ECFSPR was searched for pwCF 6 years of age and older who were not chronically infected with PA at baseline. Factors associated with inhaled antibiotic use were first assessed through a logistic regression. From this model a propensity score was computed for each individual, providing the likelihood of being treated with inhaled antibiotics. Long-term outcomes with and without inhaled antibiotics were assessed separately for propensity scores tertiles.

RESULTS: 7210 pwCF without chronic PA infection at baseline were included, with 2722 (37.75%) receiving long-term treatment with inhaled antibiotics. Treatment with inhaled antibiotics was more prevalent with severe genotype, diabetes, pancreatic insufficiency, and past infection with chronic PA (OR 3.8, 95% CI, 2.88-5.04). Treatment with inhaled antibiotics was not associated with a reduced risk for acquisition of PA or other resistant pathogens, or with improved lung function decline, mortality, or transplantation.

CONCLUSIONS: Many pwCF without chronic PA infection are receiving long-term treatment with inhaled antibiotics despite lack of support from clinical trials or practice guidelines. We did not observe improve outcomes with inhaled antibiotics. Our findings suggest controlled studies evaluating specific inhaled antibiotic regimens targeting specific pathogens or indications be performed to determine their effect.

PMID:36045028 | DOI:10.1016/j.jcf.2022.08.010

Ann Am Thorac Soc. 2022 Aug 31. doi: 10.1513/AnnalsATS.202203-201OC. Online ahead of print.

ABSTRACT

RATIONALE: Pulmonary exacerbation (PEx) events contribute to lung function decline in people with cystic fibrosis (CF). CF Foundation PEx guidelines note a short course of systemic corticosteroids may offer benefit without contributing to long-term adverse effects. However, insufficient evidence exists to recommend systemic corticosteroids for PEx treatment.

OBJECTIVES: To determine if systemic corticosteroids for the treatment of in-hospital pediatric PEx is associated with improved clinical outcomes compared to treatment without systemic corticosteroids.

METHODS: Retrospective cohort study using the CF Foundation Patient Registry-Pediatric Health Information System linked database. People with CF were included if hospitalized for a PEx between 2006-2018 and were 6-21 years of age. Time to next PEx was assessed by Cox proportional hazards regression. Lung function outcomes were assessed by linear mixed effect modeling and generalized estimating equations. To address confounding by indication, inverse probability treatment weighing was used.

RESULTS: 3,471 people with CF contributed 9,787 PEx for analysis. Systemic corticosteroids were used in 15% of all PEx. In our primary analysis, systemic corticosteroids were not associated with better pre- to post-PEx percent predicted forced expiratory volume in 1 second responses (mean difference, -0.36, 95% CI: -1.14, 0.42; p=0.4) or a higher odds of returning to lung function baseline (odds ratio (OR), 0.97, 95% CI: 0.84-1.12; p=0.7), but were associated with a reduced chance of future PEx requiring intravenous antibiotics (hazard ratio (HR), 0.91 (95% CI: 0.85-0.96; p=0.002). When restricting the analysis to one PEx per person, lung function outcomes remained no different among PEx treated with or without systemic corticosteroids, but in contrast to our primary analysis, the use of systemic corticosteroids was no longer associated with a reduced chance of having a future PEx requiring intravenous antibiotics (HR 0.96 (95% CI: 0.86, 1.07; p=0.42).

CONCLUSIONS: Systemic corticosteroid treatment for in-hospital pediatric PEx was not associated with improved lung function outcomes. Prospective trials are needed to better evaluate the risks and benefits of systemic corticosteroid use for PEx treatment in children with CF.

PMID:36044723 | DOI:10.1513/AnnalsATS.202203-201OC

IEEE Pulse. 2022 Jul-Aug;13(4):14-19. doi: 10.1109/MPULS.2022.3191445.

ABSTRACT

Ions can say a lot about a baby's health. High levels of chloride in sweat can indicate cystic fibrosis (CF), a disorder that causes respiratory and digestive problems; abnormal sodium levels are signs of increased risk for seizure or muscle problems; and too-high or too-low potassium concentrations can cause heart arrhythmias or other muscle issues. These ions-commonly called electrolytes- are also important throughout life. For instance, too much or too little sodium can lead to confusion, seizures, and muscle weakness or cramping.

PMID:36044473 | DOI:10.1109/MPULS.2022.3191445

J Assist Reprod Genet. 2022 Aug 31. doi: 10.1007/s10815-022-02599-6. Online ahead of print.

ABSTRACT

OBJECTIVE: The purpose of this study was to explore the association of expression of cystic fibrosis transmembrane conductance regulator (CFTR) in cumulus cells (CCs) from mature oocytes with oocyte quality and embryonic development.

METHODS: A total of 338 infertile women who underwent ovarian stimulation cycle of oocyte retrieval in Zhejiang University School of Medicine were retrospectively enrolled in this study. The relative mRNA expression levels of CFTR, bone morphogenetic protein 15 (BMP15), and growth differentiation factor 9 (GDF9) in CCs were detected by qPCR technology. ROC curve was applied for the diagnosis of oocyte maturation. The serum levels of anti-Müllerian hormone (AMH), E2, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and androstenedione were measured. Oocyte maturation rate, fertilization rate, cleavage rate, high-quality embryo formation rate, and implantation rate after embryo transfer were also determined.

RESULTS: The mRNA expression levels of CFTR in CCs were significantly increased in metaphase II (MII) oocytes compared to that in metaphase I (MI) or germinal vesicle (GV) oocytes. The ROC curve analysis illustrated that CFTR mRNA expression could efficiently discriminate MII oocytes from MI or GV oocytes (AUC = 0.954), and revealed that 0.695 RQU is the optimal cut-off value for diagnosis. So the cut-off value of 2-ΔΔCT = 0.70 was used to divide the patients into two groups: low- (n = 114) and high-CFTR group (n = 224). The mRNA expression of CFTR in CCs was positively correlated with the antral follicular count (AFC), number of oocytes retrieved, number of MII oocytes, serum E2 level on hCG day, and BMP15 and GDF9 expression in CCs. Under continuous stimulation with the same dose of recombinant follicle-stimulating hormone (rFSH), the number of follicles, average recovered oocytes, recovered oocytes, MII oocytes, as well as the oocyte recovery rate, fertilization rate, oocyte cleavage rate, high-quality embryo formation rate, and implantation rate were decreased in patients with lower CFTR.

CONCLUSIONS: This study suggests that CFTR expression in CCs is associated with the developmental potential of human oocytes.

PMID:36044164 | DOI:10.1007/s10815-022-02599-6

Pflugers Arch. 2022 Aug 31. doi: 10.1007/s00424-022-02742-3. Online ahead of print.

ABSTRACT

Elevated levels of the intracellular second messenger cAMP can stimulate intestinal oxalate secretion however the membrane transporters responsible are unclear. Oxalate transport by the chloride/bicarbonate (Cl-/HCO3-) exchanger Slc26a6 or PAT-1 (Putative Anion Transporter 1), is regulated via cAMP when expressed in Xenopus oocytes and cultured cells but whether this translates to the native epithelia is unknown. This study investigated the regulation of oxalate transport by the mouse intestine focusing on transport at the apical membrane hypothesizing PAT-1 is the target of a cAMP-dependent signaling pathway. Adopting the Ussing chamber technique we measured unidirectional 14C-oxalate and 36Cl- flux ([Formula: see text] and [Formula: see text]) across distal ileum, cecum and distal colon, employing forskolin (FSK) and 3-isobutyl-1-methylxanthine (IBMX) to trigger cAMP production. FSK/IBMX initiated a robust secretory response by all segments but the stimulation of net oxalate secretion was confined to the cecum only involving activation of [Formula: see text] and distinct from net Cl- secretion produced by inhibiting [Formula: see text]. Using the PAT-1 knockout (KO) mouse we determined cAMP-stimulated [Formula: see text] was not directly dependent on PAT-1, but it was sensitive to mucosal DIDS (4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid), although unlikely to be another Cl-/HCO3- exchanger given the lack of trans-stimulation or cis-inhibition by luminal Cl- or HCO3-. The cAMP-activated oxalate efflux was reliant on CFTR (Cystic Fibrosis Transmembrane conductance Regulator) activity, but only in the presence of PAT-1, leading to speculation on the involvement of a multi-transporter regulatory complex. Further investigations at the cellular and molecular level are necessary to define the mechanism and transporter(s) responsible.

PMID:36044064 | DOI:10.1007/s00424-022-02742-3

Physiother Theory Pract. 2022 Aug 31:1-11. doi: 10.1080/09593985.2022.2116300. Online ahead of print.

ABSTRACT

BACKGROUND: Abnormal glucose tolerance (AGT) in cystic fibrosis (CF) affects lung function and clinical parameters, including aerobic fitness. However, its effects on physical activity level (PAL), anaerobic power (AP), and muscle strength (MS) in children and adolescents are unknown.

PURPOSE: To investigate aerobic fitness, PAL, AP, and MS in pediatric patients with mild-to-moderate CF and AGT.

METHODS: The study included children and adolescents with CF aged 10-18 years. Participants underwent a pulmonary function test, quadriceps, and handgrip MS measurement, vertical jump test to assess AP, and six-minute walk test (6MWT) to assess aerobic fitness. Bouchard's Three-Day Physical Activity record was used to determine PAL.

RESULTS: Height z-score (p = .006), 6MWT (p = .024), handgrip (p = .028), quadriceps MS (p = .044), and AP (p = .036) were significantly lower in AGT (n = 21) than normal glucose tolerance (NGT) (n = 19). In the AGT group, glycosylated hemoglobin (HbA1c) was significantly associated with forced expiratory volume in one second (FEV1) (p = .046). 6MWT distance (6MWD) was associated with height (p = .008), FEV1 (p = .001), forced vital capacity (FVC) (p = .001), forced expiratory flow from 25% to 75% (FEF25-75%) (p = .030), handgrip MS (p = .012), and PAL (p = .034). After adjusting for height and FEV1, the groups had similar 6MWD, MS, and AP (p > .05); also, insulin was associated with MS and AP but not with 6MWT or quadriceps MS.

CONCLUSION: Measures of aerobic fitness, MS, and AP are lower in AGT, but after adjusting for height and FEV1, aerobic fitness, MS, and AP do not show substantial differences. Insulin sensitivity and resistance are associated with MS and AP.

PMID:36043898 | DOI:10.1080/09593985.2022.2116300

Respir Med Case Rep. 2022 Aug 12;39:101726. doi: 10.1016/j.rmcr.2022.101726. eCollection 2022.

ABSTRACT

A 10-year-old female with cystic fibrosis (CF), diagnosed by newborn screen, and pancreatic insufficiency was referred by gastroenterology to endocrinology for short stature (Z-score -3.5 SD). She had poor growth velocity and delayed bone age, although stunting of her growth was evident by age 6 years. Her karyotype was consistent with Turner syndrome (45,X). Growth hormone therapy has improved her growth velocity; she is tolerating it without side effects. At 12 years old, she has delayed puberty due to primary ovarian failure and will initiate estrogen replacement. Her case highlights the importance of a comprehensive evaluation for short stature in individuals with CF. Poor growth velocity and extreme short stature should not be dismissed as expected comorbidities of CF. The differential for causes of short stature is broad, with some etiologies having significant sequalae and increased morbidity beyond that already seen in CF.

PMID:36043196 | PMC:PMC9420504 | DOI:10.1016/j.rmcr.2022.101726

J Cyst Fibros. 2022 Aug 27:S1569-1993(22)00652-X. doi: 10.1016/j.jcf.2022.08.015. Online ahead of print.

NO ABSTRACT

PMID:36041887 | DOI:10.1016/j.jcf.2022.08.015

J Cyst Fibros. 2022 Aug 27:2518. doi: 10.1016/j.jcf.2022.08.011. Online ahead of print.

ABSTRACT

BACKGROUND: As people with Cystic Fibrosis (CF) live longer, extra-pulmonary complications such as CF-related bone disease (CFBD) are becoming increasingly important. The etiology of CFBD is poorly understood but is likely multifactorial. Bones undergo continuous remodeling via pathways including RANK (receptor activator of NF-κB)/sRANKL (soluble ligand)/OPG (osteoprotegerin). We sought to examine the association between sRANKL (stimulant of osteoclastogenesis) and OPG levels (inhibitor of osteoclast formation) and CFBD to investigate their potential utility as biomarkers of bone turnover in people with CF.

METHODS: We evaluated sRANKL and OPG in plasma from people with CF and healthy controls (HC) and compared levels in those with CF to bone mineral density results. We used univariable and multivariable analysis to account for factors that may impact sRANKL and OPG.

RESULTS: We found a higher median [IQR] sRANKL 10,896pg/mL [5,781-24,243] CF; 2,406pg.mL [659.50-5,042] HC; p= 0.0009), lower OPG 56.68pg/mL [36.28-124.70] CF; 583.20pg/mL [421.30-675.10] HC; p < 0.0001), and higher RANKL/OPG in people with CF no BD than in HC (p < 0.0001). Furthermore, we found a higher RANKL/OPG ratio 407.50pg/mL [214.40-602.60] CFBD; 177.70pg/mL [131.50-239.70] CF no BD; p = 0.007) in people with CFBD versus CF without bone disease. This difference persisted after adjusting for variables thought to impact bone health.

CONCLUSIONS: The current screening recommendations of imaging for CFBD may miss important markers of bone turnover such as the RANKL/OPG ratio. These findings support the investigation of therapies that modulate the RANK/RANKL/OPG pathway as potential therapeutic targets for bone disease in CF.

PMID:36041886 | DOI:10.1016/j.jcf.2022.08.011

Development. 2022 Oct 15;149(20):dev200693. doi: 10.1242/dev.200693. Epub 2022 Aug 30.

ABSTRACT

Bud tip progenitors (BTPs) in the developing lung give rise to all epithelial cell types found in the airways and alveoli. This work aimed to develop an iPSC organoid model enriched with NKX2-1+ BTP-like cells. Building on previous studies, we optimized a directed differentiation paradigm to generate spheroids with more robust NKX2-1 expression. Spheroids were expanded into organoids that possessed NKX2-1+/CPM+ BTP-like cells, which increased in number over time. Single cell RNA-sequencing analysis revealed a high degree of transcriptional similarity between induced BTPs (iBTPs) and in vivo BTPs. Using FACS, iBTPs were purified and expanded as induced bud tip progenitor organoids (iBTOs), which maintained an enriched population of bud tip progenitors. When iBTOs were directed to differentiate into airway or alveolar cell types using well-established methods, they gave rise to organoids composed of organized airway or alveolar epithelium, respectively. Collectively, iBTOs are transcriptionally and functionally similar to in vivo BTPs, providing an important model for studying human lung development and differentiation.

PMID:36039869 | DOI:10.1242/dev.200693

Pediatr Pulmonol. 2022 Aug 29. doi: 10.1002/ppul.26131. Online ahead of print.

ABSTRACT

INTRODUCTION: Lower socioeconomic status is associated with significantly poorer outcomes in weight, lung function, and pulmonary exacerbation rates in People with CF (PwCF).

GLOBAL AIM: We aim to reduce health disparities and inequities faced by PwCF by screening for and addressing unmet social needs.

SPECIFIC AIMS: We aimed to increase routine Social Determinants of Health (SDoH) screening of eligible PwCF from 0% to 95% and follow-up within two weeks for those PwCF who screened positive and requested assistance from 0% to 95% by December 31, 2021.

METHODS: The Model for Improvement methodology was employed. A process map and a simplified failure mode effects analysis chart were created for the screening and SDoH follow-up process. Those who screened positive for SDoH and requested assistance, a follow-up contact was made to offer intervention.

INTERVENTION: Adult PwCF who had at least one UVA Clinic encounter in 2021 were screened for SDoH. The SDoH screening tool included eight domains: housing, food, transportation, utilities, health-care access, medication access, income/employment and education. Follow-up was completed with all PwCF who screened positive for SDoH.

RESULTS: A total of 132 of 142, (93.0%) PwCF eligible for screening completed the SDoH screening. Of the PwCF who completed screening, 56 (42.4%) screened positive for SDoH. A follow-up rate of 100% was achieved in June 2021 and maintained through December 2021.

CONCLUSION: Implementing screening for SDOH and follow-up to mitigate social difficulties in adult PwCF at UVA was successful and could be reproduced at other CF care centers. This article is protected by copyright. All rights reserved.

PMID:36039394 | DOI:10.1002/ppul.26131

Zhonghua Er Ke Za Zhi. 2022 Sep 2;60(9):915-919. doi: 10.3760/cma.j.cn112140-20220427-00384.

ABSTRACT

Objective: To investigate the clinical phenotypes and genotypic spectrum of exocrine pancreatic insufficiency in children with cystic fibrosis. Methods: This was a retrospective analysis of 12 children with cystic fibrosis who presented to Children's Hospital of Fudan University from December 2017 to December 2021. Clinical features, fecal elastase-1 level, genotype, diagnosis and treatment were systematically reviewed. Results: A total of 12 children, 7 males and 5 females, diagnosis aged 5.4 (2.0, 10.6) years, were recruited. Common clinical features included chronic cough in 12 cases, malnutrition in 7 cases, steatorrhea in 7 cases, bronchiectasis in 5 cases and electrolyte disturbance in 4 cases. Exocrine pancreatic insufficiency were diagnosed in 8 cases,the main clinical manifestations were steatorrhea in 7 cases, of which 5 cases started in infancy; 6 cases were complicated with malnutrition, including mild in 1 case, moderate in 2 cases and severe in 3 cases; 3 cases had abdominal distension; 2 cases had intermittent abdominal pain; 4 cases showed fatty infiltration or atrophy of pancreas and 3 cases showed no obvious abnormality by pancreatic magnetic resonance imaging or B-ultrasound. All 8 children were given pancreatic enzyme replacement therapy, follow-up visit of 2.3 (1.2,3.2) years. Diarrhea significantly improved in 6 cases, and 1 case was added omeprazole due to poor efficacy. A total of 20 variations of CFTR were detected in this study, of which 7 were novel (c.1373G>A,c.1810A>C,c.270delA,c.2475_2478dupCGAA,c.2489_c.2490insA, c.884delT and exon 1 deletion). Conclusions: There is a high proportion of exocrine pancreatic insufficiency in Chinese patients with cystic fibrosis. The main clinical manifestations are steatorrhea and malnutrition. Steatorrhea has often started from infancy. Pancreatic enzyme replacement therapy can significantly improve the symptoms of diarrhea and malnutrition.

PMID:36038301 | DOI:10.3760/cma.j.cn112140-20220427-00384

Anal Chim Acta. 2022 Sep 8;1225:340161. doi: 10.1016/j.aca.2022.340161. Epub 2022 Jul 18.

ABSTRACT

Contactless conductivity detection (C4D) as a universal detection technique plays an important role in combination with efficient electrophoretic separation carried out in capillaries (CE) or on microchips (ME) in the analysis of clinical samples. C4D is particularly sensitive in the quantification of low molecular weight biogenic substances such as inorganic cations and anions, amino acids, amines, low molecular weight organic acids, saccharides and many drugs such as antibiotics, analgesics, anaesthetics or antiepileptics. Biogenic substances are determined in CE/C4D or ME/C4D directly in their native form without derivatization and sample matrix treatment is often based only on dilution or addition of an organic solvent. The limit of detection for most CE/C4D determinations is at the micromolar concentration level, which is sufficient to monitor physiological or therapeutic levels of most of low molecular weight biogenic substances. Therefore, CE/C4D and ME/C4D are widely used for sequential monitoring of nutrients, metabolites and waste products at the level of individual tissues and organs, low-invasive detection of inborn errors of metabolism and cystic fibrosis, pharmacokinetic monitoring and therapeutic drug monitoring. Innovative trends such as electrophoretic stacking, microdialysis, electromembrane extraction, portable and disposable CE instruments and minimally invasive clinical sampling techniques are mentioned. A critical evaluation of the positives and negatives of this technique is presented, covering the main applications published over the last 10 years.

PMID:36038247 | DOI:10.1016/j.aca.2022.340161

ACS Nano. 2022 Aug 29. doi: 10.1021/acsnano.2c05647. Online ahead of print.

ABSTRACT

Despite lipid nanoparticles' (LNPs) success in the effective and safe delivery of mRNA vaccines, an inhalation-based mRNA therapy for lung diseases remains challenging. LNPs tend to disintegrate due to shear stress during aerosolization, leading to ineffective delivery. Therefore, LNPs need to remain stable through the process of nebulization and mucus penetration, yet labile enough for endosomal escape. To meet these opposing needs, we utilized PEG lipid to enhance the surficial stability of LNPs with the inclusion of a cholesterol analog, β-sitosterol, to improve endosomal escape. Increased PEG concentrations in LNPs enhanced the shear resistance and mucus penetration, while β-sitosterol provided LNPs with a polyhedral shape, facilitating endosomal escape. The optimized LNPs exhibited a uniform particle distribution, a polyhedral morphology, and a rapid mucosal diffusion with enhanced gene transfection. Inhaled LNPs led to localized protein production in the mouse lung without pulmonary or systemic toxicity. Repeated administration of these LNPs led to sustained protein production in the lungs. Lastly, mRNA encoding the cystic fibrosis transmembrane conductance regulator (CFTR) was delivered after nebulization to a CFTR-deficient animal model, resulting in the pulmonary expression of this therapeutic protein. This study demonstrated the rational design approach for clinical translation of inhalable LNP-based mRNA therapies.

PMID:36038136 | DOI:10.1021/acsnano.2c05647

Bioorg Med Chem. 2022 Jul 26;72:116945. doi: 10.1016/j.bmc.2022.116945. Online ahead of print.

ABSTRACT

Chronic mucoid P. aeruginosa cystic fibrosis (CF) lung infections are associated with the development of a biofilm composed of anionic acetylated exopolysaccharide (EPS) alginate, electrostatically stabilised by extracellular Ca2+ ions. OligoG CF-5/20, a low molecular weight guluronate rich oligomer, is emerging as a novel therapeutic capable of disrupting mature P. aeruginosa biofilms. However, its method of therapeutic action on the mucoid biofilm EPS is not definitively known at a molecular level. This work, utilising molecular dynamics (MD) and Density-Functional Theory (DFT), has revealed that OligoG CF-5/20 interaction with the EPS is facilitated solely through bridging Ca2+ ions, which are not liberated from their native EPS binding sites upon OligoG CF-5/20 dispersal, suggesting that OligoG CF-5/20 does not cause disruptions to mature P. aeruginosa biofilms through breaking EPS-Ca2+-EPS ionic cross-links. Rather it is likely that the therapeutic activity arises from sequestering free Ca2+ ions and preventing further Ca2+ induced EPS aggregation.

PMID:36037625 | DOI:10.1016/j.bmc.2022.116945

Eur J Drug Metab Pharmacokinet. 2022 Aug 29. doi: 10.1007/s13318-022-00791-8. Online ahead of print.

ABSTRACT

BACKGROUND AND OBJECTIVE: Elexacaftor/tezacaftor/ivacaftor is highly effective in treating people with cystic fibrosis (pwCF) who have ≥ 1 responsive mutation. Liver disease occurs in approximately 10%-20% of pwCF. The objective of this study was to assess the safety and pharmacokinetics of elexacaftor/tezacaftor/ivacaftor in people with moderate hepatic impairment, which is necessary to inform on its use and guide dosing recommendations.

METHODS: The safety and pharmacokinetics of elexacaftor/tezacaftor/ivacaftor were evaluated in subjects without CF with moderate hepatic impairment versus matched healthy controls. Twenty-two subjects (11 with moderate hepatic impairment and 11 healthy subjects) received half the standard adult daily dose of elexacaftor/tezacaftor/ivacaftor (elexacaftor 100 mg/tezacaftor 50 mg/ivacaftor 150 mg) orally for 10 days.

RESULTS: Elexacaftor/tezacaftor/ivacaftor was safe and well tolerated in subjects with moderate hepatic impairment and healthy controls. On day 10, the mean values of the area under the curve during the dosing interval (AUCτ) for total (bound and unbound) elexacaftor and its major active metabolite M23-elexacaftor were increased 1.25-fold (95% CI 1.01, 1.54) and 1.73-fold (95% CI 1.27, 2.35), respectively, in subjects with moderate hepatic impairment compared with matched healthy subjects. The mean values of AUCτ for ivacaftor and tezacaftor were increased 1.50-fold (95% CI 1.09, 2.06) and 1.20-fold (95% CI 1.00, 1.43), respectively, while the mean value of AUCτ for the active metabolite M1-tezacaftor was 1.29-fold lower [ratio of moderate hepatic impairment to healthy subjects (95% CI): 0.778 (0.655, 0.924)] in subjects with moderate hepatic impairment.

CONCLUSIONS: A dose reduction of elexacaftor/tezacaftor/ivacaftor is warranted in people with moderate hepatic impairment. (Trial registry number 2018-002570-40; registered 2 July 2018.).

PMID:36036885 | DOI:10.1007/s13318-022-00791-8

Am J Physiol Cell Physiol. 2022 Aug 29. doi: 10.1152/ajpcell.00303.2022. Online ahead of print.

ABSTRACT

Professor Hans H. Ussing (1911-2000) was one of the founding members of the field of epithelial cell biology. He is most famous for the electrophysiological technique that he developed to measure electrogenic ion flux across epithelial tissues. Ussing-style electrophysiology has been applied to multiple tissues and has informed fields as diverse as amphibian biology and medicine. In the latter, this technique has contributed to a basic understanding of maladies such as hypertension, polycystic kidney disease, cystic fibrosis and diarrheal diseases to mention but a few. In addition to this valuable contribution to biological methods, Prof. Ussing also provided strong evidence for the concept of active transport several years before the elucidation of Na+K+ATPase. In addition, he provided cell biologists with the important concept of polarized epithelia with specific and different transporters found in the apical and basolateral membranes thus providing these cells with the ability to conduct directional, active and passive transepithelial transport. My studies have used Ussing chamber electrophysiology to study toad urinary bladder, an amphibian cell line, renal cells lines and, most recently, choroid plexus cell lines. This technique has formed the basis of our in vitro mechanistic studies that are used in an iterative manner with animal models to better understand disease progress and treatment. I was honored to be invited to deliver the 2022 Hans Ussing Lecture sponsored by the Epithelial Transport Group of the American Physiological Society. This manuscript is a version of the material presented in that lecture.

PMID:36036449 | DOI:10.1152/ajpcell.00303.2022

Chest. 2022 Aug 25:S0012-3692(22)03684-4. doi: 10.1016/j.chest.2022.08.2216. Online ahead of print.

ABSTRACT

BACKGROUND: Following evidence from randomized controlled trials, patients with bronchiectasis unrelated to cystic fibrosis (CF) receive long-term azithromycin to reduce acute respiratory exacerbations. However, the period when azithromycin is effective and those likely to most benefit remains unknown.

RESEARCH QUESTIONS: (i) What is the period following its commencement when azithromycin is most effective? and (ii) What factors may modify azithromycin effects?

STUDY DESIGN AND METHODS: A secondary analysis was conducted of our previous randomized controlled trial involving 89 Indigenous children with bronchiectasis unrelated to CF. Semi-parametric poisson regression identified the azithromycin efficacy period. Multivariable poisson regression identified factors that modify azithromycin effect.

RESULTS: Azithromycin was associated with fewer exacerbations per child-week during weeks 4-96, with the most effective period observed between weeks 17-62. Eleven factors were associated with different azithromycin effects, four of them were significant at p<0.05 level. Compared with their counterparts, higher reduction in excerbations was observed in: children with nasopharyngeal carriage of bacterial pathogens, [incidence rate ratio, IRR=0.81 (95% confidence interval 0.57 to 1.14) versus 0.29 (0.20 to 0.44), p<0.001]; New Zealand children [IRR=0.73 (0.51 to 1.03) versus 0.39 (0.28 to 0.55), p=0.012]; and those with higher weight-for-height z-scores [interaction IRR=0.82 (0.67 to 0.99), p=0.044]. Compared with their counterparts, lower reduction was observed in those born preterm [IRR=0.41 (0.30 to 0.55) versus 0.74 (0.49 to 1.10), p=0.012].

INTERPRETATION: Regular azithromycin is best used for at least 17-weeks and up to 62-weeks as these periods provide maximum benefit for Indigenous children with bronchiectasis unrelated to CF. Several factors modified azithromycin benefits, however these traits need confirmation in larger studies before being adopted into clinical practice.

PMID:36030839 | DOI:10.1016/j.chest.2022.08.2216

Spec Care Dentist. 2022 Aug 27. doi: 10.1111/scd.12773. Online ahead of print.

ABSTRACT

AIMS: To evaluate the dental attendance, oral hygiene habits, and dietary habits of adults with Cystic Fibrosis in the Republic of Ireland.

METHODS AND RESULTS: A cross-sectional study was carried out using a structured anonymous questionnaire. A total of 71 adults with Cystic Fibrosis responded. While the majority of respondents (66.2%) saw a dentist in the preceding year, 15.5% had not attended a dentist for over 2 years. Smoking and alcohol consumption levels were low. 63.4% brushed twice or more daily, with 70.4% using a Fluoride containing toothpaste. 62% did not use any interdental cleaning aid. 5.6% changed their toothbrush at least once a month, but for 22.5% it was over 6 months. 70.4% used fluoride toothpaste. 38% snacked three or more times daily and 29.5% consumed fizzy drinks at least once daily.

CONCLUSIONS: The alcohol and tobacco consumption in this study group was low. However, a large proportion frequently consumed sugar-rich foods, and they did not change their toothbrush, brush their teeth, or attend the dentist as regularly as is advised. More targeted advice may be necessary to improve the oral hygiene habits of adults with Cystic Fibrosis.

PMID:36029268 | DOI:10.1111/scd.12773