The Prognostic Value of Olfactory Dysfunction in Patients with COVID-19: The COVIDORA Study.

BACKGROUND: Among all studies describing COVID-19 clinical features during the first wave of the pandemic, only a few retrospective studies have assessed the correlation between olfac-tory dysfunction (OD) and the evolution of disease severity. The main aim was to assess whether OD is a predictive factor of COVID-19 severity based on the patient's medical management (outpa-tient care, standard hospital admission, and ICU admission). METHODS: A national, prospective, mul-ticenter cohort study was conducted in 20 public hospitals and a public center for COVID-19 screen-ing. During the first wave of the pandemic, from 6 April to 11 May 2020, all patients tested positive for COVID-19 confirmed by RT-PCR underwent two follow-up ENT consultations within 10 days of symptom onset. The main outcome measures were the evolution of medical management (out-patient care, standard hospital admission, and ICU admission) at diagnosis and along the clinical course of COVID-19 disease. RESULTS: Among 481 patients included, the prevalence of OD was 60.7%, and it affected mostly female patients (74.3%) under 65 years old (92.5%), with fewer comor-bidities than patients with normal olfactory function. Here, 99.3% (290/292) of patients with OD presented with non-severe COVID-19 disease. Patients reporting OD were significantly less hospi-talized than the ones managed as outpatients, in either a standard medical unit or an ICU. Conclu-sions: As regards the clinical course of COVID-19 disease, OD could predict a decreased risk of hospitalization during the first wave of the pandemic.

Impact of the COVID-19 pandemic and associated lockdown measures on the management, health, and behavior of the cystic fibrosis population in France during 2020 (MUCONFIN).

Background: Most of the studies on cystic fibrosis (CF) focused on SARS-CoV-2 prevalence and suggested a low incidence of infection in this population. We aimed to assess the impact of the pandemic and related lockdown measures implemented in May 2020 in response to the first wave of SARS-CoV-2 infection on healthcare access, health, and behavior in CF patients. Methods: A national questionnaire opened online from May 15th, 2020 to June 11th, 2020 was completed by 751 CF-patients, aged 14 years and over. It comprised questions about access to healthcare, anxiety and depression, smoking, alcohol, drug and psychotropic drug consumption, adherence to CF treatment, and constraints. A semi-structured comprehensive interview was performed no later than 1 month after the end of the lockdown in 16 CF-patients. Results: The mean age of the population was 28.0 [interquartile range (IQR) 20.0-37.0] years old. More than 75% of in-person consultations scheduled during the lockdown were canceled. Alternatively, 27% were postponed, and telehealth consultations were proposed and accepted in almost 40% of cases. More than 75% of the scheduled physiotherapy sessions were canceled and replaced mainly by self-drainage. Annual follow-up clinic visits were consistently postponed whereas required hospitalizations at CF centers for exacerbation were maintained in most cases. While 43.2% CF-patients had signs of anxiety, 51.0% presented symptoms of depression, both associated with increased use of psychotic medications and inversely correlated to COVID-19 prevalence. Among the lower and lower middle classes, very little medical information was obtained or requested by the patient, participation to sports or other activities was low, while excessive home confinement and isolation were more frequent. In contrast, in the upper middle and upper classes, individuals solicitated help to their CF centre, had more physical activities, and maintained contact with friends or families. Conclusion: The first lockdown in France had only minimal impact on the management care of CF-patients but was associated with increased symptoms of anxiety and depression, together with behavioral changes that varied with social class. Trial registration: NCT04463628.

Phosphorylation of the Chaperone-Like HspB5 Rescues Trafficking and Function of F508del-CFTR.

Cystic Fibrosis is a lethal monogenic autosomal recessive disease linked to mutations in Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. The most frequent mutation is the deletion of phenylalanine at position 508 of the protein. This F508del-CFTR mutation leads to misfolded protein that is detected by the quality control machinery within the endoplasmic reticulum and targeted for destruction by the proteasome. Modulating quality control proteins as molecular chaperones is a promising strategy for attenuating the degradation and stabilizing the mutant CFTR at the plasma membrane. Among the molecular chaperones, the small heat shock protein HspB1 and HspB4 were shown to promote degradation of F508del-CFTR. Here, we investigated the impact of HspB5 expression and phosphorylation on transport to the plasma membrane, function and stability of F508del-CFTR. We show that a phosphomimetic form of HspB5 increases the transport to the plasma membrane, function and stability of F508del-CFTR. These activities are further enhanced in presence of therapeutic drugs currently used for the treatment of cystic fibrosis (VX-770/Ivacaftor, VX-770+VX-809/Orkambi). Overall, this study highlights the beneficial effects of a phosphorylated form of HspB5 on F508del-CFTR rescue and its therapeutic potential in cystic fibrosis.

Unsolved severe chronic rhinosinusitis elucidated by extensive CFTR genotyping.

Severe chronic rhinosinusitis in children should alert clinicians and extensive CFTR genotyping should be performed. We propose that thorough clinical and functional assessment in severe chronic rhinosinusitis is valuable to discover rare mutations which could be treated by CFTR correctors to postpone pulmonary infection.

Computed Tomography Description of the Uncinate Process Angulation in Patients With Cystic Fibrosis and Comparison With Primary Ciliary Dyskinesia, Nasal Polyposis, and Controls.

BACKGROUND:: There is a medial bulging of the lateral nasal wall in patients with cystic fibrosis (CF). AIMS:: Uncinate process (UP) angulation measurements in patients and controls to objectify this bulging. MATERIALS AND METHODS:: Thirty CF, 17 primary ciliary dyskinesia (PCD), 13 chronic rhinosinusitis with polyps (CRSwp), and 30 controls were included. Angles were measured bilaterally on computed tomography (CT) scans: A, B, C on coronal sections, D and E on axial sections. Angle A was between the UP and the orbit inner wall, whereas the others were between UP and midline. RESULTS:: There was no significant difference between controls, PCD, and CRSwp. However, CF had 3 statistically different angles with controls, 5 with CRSwp, and 4 with PCD. Angle A average value was 126° (±16°) in patients with CF, 138° (±19°) in controls ( P = .007), 145° (±15°) in PCD ( P = .001), and 138° (±14°) in CRSwp ( P = .001). Angle E average value was 35° (±10°) in patients with CF, 20° (±6°) in controls ( P < .001), 21° (±4°) in PCD ( P < .001), and 22° (±6°) in CRSwp ( P < .001). CONCLUSION:: Uncinate process's anatomy is only modified in CF: Angle between UP and inner wall of orbit is closed, and angles between UP and midline are opened. SIGNIFICANCE:: These measures quantify the medial bulging of lateral nasal wall and support nasofibroscopic observations.

Exophytic sinonasal papillomas and nasal florid papillomatosis: A retrospective study.

BACKGROUND: Sinonasal exophytic papillomas are rare. The multifocal form, florid papillomatosis, has not been yet described in literature. We report on the clinical features and the management of the different forms of exophytic papilloma. METHODS: A retrospective study was conducted that included all patients with exophytic papilloma treated in our center over the past 12 years. We recorded clinical presentation, treatments, recurrences, pathology (p16 expression and human papillomavirus [HPV] status). RESULTS: We included 13 patients with a mean follow-up of 5 years. The main location of exophytic papilloma was the anterior part of the septum. Lesions were multifocal in 3 patients corresponding to florid papillomatosis. The main treatment was surgery. Cases of HPV-11 or HPV-6 were present in all forms of exophytic papilloma (dysplasia in 4 cases). Late recurrences occurred in 3 patients (2 patients with florid papillomatosis) over a period of 3 years. CONCLUSION: Exophytic papilloma has 2 clinical presentations: localized and diffuse. Patients with florid papillomatosis should be monitored closely as recurrence seems to be frequent.

How your ears can tell what is hidden in your heart: wild-type transthyretin amyloidosis as potential cause of sensorineural hearing loss inelderly-AmyloDEAFNESS pilot study.

BACKGROUND: Wild-type transthyretin amyloidosis (ATTRwt) is an age-related life-threatening condition. Prognosis is mainly dependent on cardiac involvement. Other organs and tissues may be affected. Their early recognition may increase awareness of physicians and positively affects the prognosis. Presbycusis is another age-related disorder. Whether this disease is associated to ATTRwt amyloidosis is unknown. METHODS: Sixteen consecutive patients with confirmed diagnosis of ATTRwt amyloidosis at the Mondor Amyloidosis Network, France, underwent otoscopy and audiological tests including pure tone audiometry, speech reception threshold and speech discrimination score. RESULTS: The mean age was 79 ± 5 years. All were male with an NYHA average of 2.5 ± 0.8. All the patients had sensorineural hearing loss that seemed to preexist to cardiac disorder with greater severity than expected for their age. For speech discrimination test, the mean speech reception threshold was 28 ± 15 dB and the mean speech discrimination score was 68 ± 16 at 40 dB. Ten patients (62.5%) failed to recognize 100% of the words. Compared to age-related expectations according to statistical distribution (ISO), hearing loss included all frequencies and was more severe in patients with ATTRwt amyloidosis. CONCLUSIONS: These findings suggest that amyloid deposits could infiltrate the various anatomical structures of the inner ear. Description of specific audiologic pattern of ATTRwt amyloidosis might be proposed as a "red flag" and could help for early identification of patients who may be at high risk of ATTRwt amyloidosis as specific treatments are available.

New use for an old drug: COX-independent anti-inflammatory effects of sulindac in models of cystic fibrosis.

BACKGROUND AND PURPOSE: Pulmonary disease is the main cause of morbidity and mortality in cystic fibrosis (CF) patients due to exacerbated inflammation. To date, the only anti-inflammatory drug available to CF patients is high-dose ibuprofen, which can slow pulmonary disease progression, but whose cyclooxygenase-dependent digestive adverse effects limit its clinical use. Here we have tested sulindac, another non-steroidal anti-inflammatory drug with an undefined anti-inflammatory effect in CF airway epithelial cells. EXPERIMENTAL APPROACH: Using in vitro and in vivo models, we NF-κB activity and IL-8 secretion. In HeLa-F508del cells, we performed luciferase reporter gene assays in order to measure i) IL-8 promoter activity, and ii) the activity of synthetic promoter containing NF-κB responsive elements. We quantified IL-8 secretion in airway epithelial CFBE cells cultured at an air-liquid interface and in a mouse model of CF. KEY RESULTS: Sulindac inhibited the transcriptional activity of NF-κB and decreased IL-8 transcription and secretion in TNF-α stimulated CF cells via a cyclooxygenase-independent mechanism. This effect was confirmed in vivo in a mouse model of CF induced by intra-tracheal instillation of LPS, with a significant decrease of the induction of mRNA for MIP-2, following treatment with sulindac. CONCLUSION AND IMPLICATIONS: Overall, sulindac decrease lung inflammation by a mechanism independent of cycolooxygenase. This drug could be beneficially employed in CF.

Proteomic analysis of nasal epithelial cells from cystic fibrosis patients.

The pathophysiology of cystic fibrosis (CF) lung disease remains incompletely understood. New explanations for the pathogenesis of CF lung disease may be discovered by studying the patterns of protein expression in cultured human nasal epithelial cells (HNEC). To that aim, we compared the level of protein expressions in primary cultures of HNEC from nasal polyps secondary to CF (CFNP, n = 4), primary nasal polyps (NP, n = 8) and control mucosa (CTRL, n = 4) using isobaric tag for relative and absolute quantification (iTRAQ) labeling coupled with liquid chromatography (LC)-MS-MS. The analysis of the data revealed 42 deregulated protein expressions in CFNP compared to NP and CTRL, suggesting that these alterations are related to CF. Overall, AmiGo analysis highlighted six major pathways important for cell functions that seem to be impaired: metabolism, G protein process, inflammation and oxidative stress response, protein folding, proteolysis and structural proteins. Among them, glucose and fatty acid metabolic pathways could be impaired in CF with nine deregulated proteins. Our proteomic study provides a reproducible set of differentially expressed proteins in airway epithelial cells from CF patients and reveals many novel deregulated proteins that could lead to further studies aiming to clarify the involvement of such proteins in CF pathophysiology.

Frontal sinus obliteration with autologous calvarial bone graft: indications and results.

Despite increasing advances in endonasal frontal sinus surgery, frontal sinus obliteration (FSO) is sometimes necessary after failure of other surgical techniques. This procedure has been reported with autologous tissue or synthetic material, but few studies have reported results with autologous calvarial bone graft. The aim of this study was to report our experience with osteoplastic FSO calvarial bone graft. A retrospective review was performed on 11 patients operated upon for FSO with autologous calvarial bone graft from 2005 to 2011. Obliteration was indicated for chronic symptomatic frontal sinusitis with nasofrontal duct stenosis in five cases of nasal polyposis with a history of endoscopic sinus surgery, two cases of frontal trauma, two of surgery for frontal inverted papilloma and two of chronic frontal purulent sinusitis. Ten patients had a history of one or two previous functional endoscopic sinus surgery (FESS) procedures. On outcome assessment, eight patients had no residual complaints after FSO and all patients showed improvement in symptoms. Frontal sinus obliteration with autologous calvarial bone graft showed low donor site morbidity and good aesthetic results. This procedure should be considered in severe frontal sinusitis after repeated FESS procedures have failed.

Identification of a novel 5' alternative CFTR mRNA isoform in a patient with nasal polyposis and CFTR mutations.

Cystic fibrosis may be revealed by nasal polyposis (NP) starting early in life. We performed cystic fibrosis transmembrane conductance regulator (CFTR) DNA and mRNA analyses in the family of a 12-year-old boy presenting with NP and a normal sweat test. Routine DNA analysis only showed the heterozygous c.2551C>T (p.Arg851*) mutation in the child and the father. mRNA analysis showed partial exon skipping due to c.2551C>T and a significant increase in total CFTR mRNA in the patient and the mother, which was attributable to the heterozygous c. -2954G>A variant in the distant promoter region, as demonstrated by in vitro luciferase assays. The 5' rapid amplification of cDNA ends analysis showed the presence of a novel transcript, where the canonical exon 1 was replaced by an alternative exon called 1a-Long. This case report could represent the first description of a CFTR-related disorder associated with the presence of a 5' alternative, probably nonfunctional transcript, similar to those of fetal origin.

CFTR dysfunction induces vascular endothelial growth factor synthesis in airway epithelium.

Peribronchial angiogenesis may occur in cystic fibrosis and vascular endothelial growth factor (VEGF)-A regulates angiogenesis in airways. Peribronchial vascularity and VEGF-A expression were examined using immunocytochemistry and morphometric analysis in lung sections obtained in 10 cystic fibrosis patients at transplantation versus 10 control nonsmokers, and in two strains of Cftr-deficient mice versus wild-type littermates. Airway epithelial NCI-H292 cells and primary cultures of noncystic fibrosis human airway epithelial cells were treated with cystic fibrosis transmembrane conductance regulator (CFTR) inhibitors (CFTR-inh(172) or PPQ-102) or transfected with a CFTR small interfering (si)RNA with or without a selective epidermal growth factor receptor tyrosine kinase inhibitor. Concentrations of VEGF-A and phosphorylated epidermal growth factor receptor were measured by ELISA. Peribronchial vascularity was increased in cystic fibrosis patients, but not in Cftr-deficient mice. VEGF-A immunostaining was localised to airway epithelium and was increased in cystic fibrosis patients and in Cftr-deficient mice. In cultured airway epithelial cells, treatment with CFTR inhibitors or transfection with CFTR siRNA induced a twofold increase in VEGF-A production. CFTR inhibitors triggered epidermal growth factor receptor phosphorylation that was required for VEGF-A synthesis. Cystic fibrosis airways at transplantation showed increased peribronchial vascularity and epithelial VEGF-A expression. CFTR dysfunction triggered epithelial synthesis of VEGF-A, which may contribute to vascular remodelling.

EMMPRIN modulates epithelial barrier function through a MMP-mediated occludin cleavage: implications in dry eye disease.

Dry eye is a common disease that develops as a result of alteration of tear fluid, leading to osmotic stress and a perturbed epithelial barrier. Matrix metalloproteinase-9 (MMP-9) may be important in dry eye disease, as its genetic knockout conferred resistance to the epithelial disruption. We show that extracellular matrix metalloproteinase inducer (EMMPRIN; also termed CD147), an inducer of MMP expression, participates in the pathogenesis of dry eye through MMP-mediated cleavage of occludin, an important component of tight junctions. EMMPRIN expression was increased on the ocular surface of dry eye patients and correlated with those of MMP-9. High osmolarity in cell culture, mimicking dry eye conditions, increased both EMMPRIN and MMP-9 and resulted in the disruption of epithelial junctions through the cleavage of occludin. Exogenously added recombinant EMMPRIN had similar effects that were abrogated in the presence of the MMP inhibitor marimastat. Membrane occludin immunostaining was markedly increased in the apical corneal epithelium of both EMMPRIN and MMP-9 knock-out mice. Furthermore, an inverse correlation between EMMPRIN and occludin membrane staining was consistently observed both in vitro and in vivo as a function of corneal epithelial cells differentiation. These data suggest a possible role of EMMPRIN in regulating the amount of occludin at the cell surface in homeostasis beyond pathological situations such as dry eye disease, and EMMPRIN may be essential for the formation and maintenance of organized epithelial structure.

A recurrent deep-intronic splicing CF mutation emphasizes the importance of mRNA studies in clinical practice.

BACKGROUND: The identification by CFTR mRNA studies of a new deep-intronic splicing mutation, c.870-1113_1110delGAAT, in one patient of our series with mild CF symptoms and in three CF patients of an Italian study, led us to evaluate the mutation frequency and phenotype/genotype correlations. METHODS: 266 patients with CF and related disorders and having at least one undetected mutation, were tested at the gDNA level in three French reference laboratories. RESULTS: In total, the mutation was found in 13 unrelated patients (5% of those already carrying a mutation) plus 4 siblings, including one homozygote and 12 heterozygotes having a severe CF mutation. The sweat test was positive in 10/14 documented cases, the diagnosis was delayed after 20 years in 9/15 and pancreatic insufficiency was present in 5/16. CONCLUSION: c.870-1113_1110delGAAT should be considered as CF-causing with phenotype variability and overall delayed diagnosis. Its frequency highlights the potential of mRNA studies.

Polypectomy compared with ethmoidectomy in the treatment of nasal polyposis.

OBJECTIVE: To compare the 3-year results of 2 endoscopic surgical approaches in the management of nasal polyposis. DESIGN: Retrospective medical record review. SETTING: Private or institutional practice. PATIENTS: A total of 127 patients with nasal polyposis were operated on by the same surgeon between January 1, 2003, and September 31, 2005. INTERVENTION: The patients underwent radical ethmoidectomy (n = 77) and polypectomy (n = 50). MAIN OUTCOME MEASURES: Outcome measures were global functional score, calculated by summing the scores (0-3) of each symptom (congestion, rhinorrhea, anosmia, hyperreactivity, and pain); global anatomical score (GAS), calculated by summing the score of polyp development for each nasal cavity; computed tomography score; adherence to corticosteroid therapy; oral corticosteroid consumption; and complication and subsequent operation rate. Efficacy was evaluated by comparing these data preoperatively and postoperatively (at 3 months, 1 year, and 3 years). RESULTS: The global functional score and GAS were significantly improved 3 years after these techniques were performed (global functional score changes from 8.65 to 3.11 for ethmoidectomy and from 8.15 to 4.2 for polypectomy; GAS, from 5.95 to 1.83 for ethmoidectomy and from 6.57 to 3.58 for polypectomy). Congestion, pain, and GAS were improved to a significantly greater extent in the ethmoidectomy group. The subsequent operation rate for symptomatic polyp recurrence was comparable (9.1% vs 8.0%), with fewer local complications in the polypectomy group. CONCLUSION: Polypectomy seems to represent a valuable alternative in the armamentarium of first-hand surgical procedures for treating nasal polyposis.

Otologic features in children with primary ciliary dyskinesia.

OBJECTIVES: To analyze otologic features in patients with primary ciliary dyskinesia (PCD) aged 0 to 18 years and to evaluate the correlation between ultrastructural defects and severity of otologic features. DESIGN: Retrospective study. SETTING: Pediatric referral center. PATIENTS: Fifty-eight patients with PCD were evaluated in the following 4 age intervals: group 1, preschool (≤ 5 years [n = 47]); group 2, school (6-11 years [n = 50]); group 3, teenagers (12-17 years [n = 34]); and group 4, young adults (≥ 18 years; 27 years for the oldest [n = 10]). Follow-up was 2 to 6 years in each age group; 26 patients had total follow-up of more than 12 years. Ultrastructural defects occurred in the outer dynein arm (n = 33), the inner dynein arm (n = 13), and the central complex (n = 11). One patient had typical Kartagener syndrome with typical PCD features but normal ciliary ultrastructure. MAIN OUTCOME MEASURES: Frequency of acute otitis media, otitis media with effusion, otorrhea, chronic otitis media, hearing loss, and middle ear surgery and type of antibiotic regimen according to age and type of defect. RESULTS: Recurrent acute otitis media decreased from group 1 (32 of 47 [68%]) to group 4 (0 of 10 [0%]) (P < .001). Otitis media with effusion was more severe in groups 1 through 3 than in group 4 (P = .02). Otorrhea decreased in group 4: 30% vs 80% (3 of 10 vs 36 of 41) in the other groups (P < .001). Half of the patients with tympanostomy tubes eventually had tympanic perforation. Hearing loss was moderate in groups 1 through 3 and mild in group 4. Continuous antibiotic therapy could be slightly reduced only in group 4. Central complex defect was a significant marker of severity for all these criteria. CONCLUSIONS: Despite continuous antibiotic therapy, the middle ear condition in PCD remained severe throughout childhood, with improvement only after age 18 years. Armstrong grommet placement did not improve the middle ear condition. Central complex defect is a marker of severity.

Effect of neutrophil elastase and its inhibitor EPI-hNE4 on transepithelial sodium transport across normal and cystic fibrosis human nasal epithelial cells.

BACKGROUND: Hyperactivity of the epithelial sodium (Na+) channel (ENaC) and increased Na+ absorption by airway epithelial cells leading to airway surface liquid dehydration and impaired mucociliary clearance are thought to play an important role in the pathogenesis of cystic fibrosis (CF) pulmonary disease. In airway epithelial cells, ENaC is constitutively activated by endogenous trypsin-like serine proteases such as Channel-Activating Proteases (CAPs). It was recently reported that ENaC activity could also be stimulated by apical treatment with human neutrophil elastase (hNE) in a human airway epithelial cell line, suggesting that hNE inhibition could represent a novel therapeutic approach for CF lung disease. However, whether hNE can also activate Na+ reabsorption in primary human nasal epithelial cells (HNEC) from control or CF patients is currently unknown. METHODS: We evaluated by short-circuit current (Isc) measurements the effects of hNE and EPI-hNE4, a specific hNE inhibitor, on ENaC activity in primary cultures of HNEC obtained from control (9) and CF (4) patients. RESULTS: Neither hNE nor EPI-hNE4 treatments did modify Isc in control and CF HNEC. Incubation with aprotinin, a Kunitz-type serine protease inhibitor that blocks the activity of endogenous CAPs, decreased Isc by 27.6% and 54% in control and CF HNEC, respectively. In control and CF HNEC pretreated with aprotinin, hNE did significantly stimulate Isc, an effect which was blocked by EPI-hNE4. CONCLUSIONS: These results indicate that hNE does activate ENaC and transepithelial Na+ transport in both normal and CF HNEC, on condition that the activity of endogenous CAPs is first inhibited. The potent inhibitory effect of EPI-hNE4 on hNE-mediated ENaC activation observed in our experiments highlights that the use of EPI-hNE4 could be of interest to reduce ENaC hyperactivity in CF airways.

Modulation of epithelial sodium channel trafficking and function by sodium 4-phenylbutyrate in human nasal epithelial cells.

Sodium 4-phenylbutyrate (4-PBA) has been shown to correct the cellular trafficking of several mutant or nonmutant plasma membrane proteins such as cystic fibrosis transmembrane conductance regulator through the expression of 70-kDa heat shock proteins. The objective of the study was to determine whether 4-PBA may influence the functional expression of epithelial sodium channels (ENaC) in human nasal epithelial cells (HNEC). Using primary cultures of HNEC, we demonstrate that 4-PBA (5 mm for 6 h) markedly stimulated amiloride-sensitive sodium channel activity and that this was related to an increased abundance of alpha-, beta-, and gamma-ENaC subunits in the apical membrane. The increase in ENaC cell surface expression (i) was due to insertion of newly ENaC subunits as determined by brefeldin A experiments and (ii) was not associated with cell surface retention of ENaC subunits because endocytosis of ENaC subunits was unchanged. In addition, we find that ENaC co-immunoprecipitated with the heat shock protein constitutively expressed Hsc70, that has been reported to modulate ENaC trafficking, and that 4-PBA decreased Hsc70 protein level. Finally, we report that in cystic fibrosis HNEC obtained from two cystic fibrosis patients, 4-PBA increased functional expression of ENaC as demonstrated by the increase in amiloride-sensitive sodium transport and in alpha-, beta-, and gamma-ENaC subunit expression in the apical membrane. Our results suggest that in HNEC, 4-PBA increases the functional expression of ENaC through the insertion of new alpha-, beta-, and gamma-ENaC subunits into the apical membrane and also suggest that 4-PBA could modify ENaC trafficking by reducing Hsc70 protein expression.