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 11^th, 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.

Use of a navigation system in endonasal surgery: Impact on surgical strategy and surgeon satisfaction. A prospective multicenter study

OBJECTIVES

Surgical navigation systems (SNS) are now widely used in endoscopic endonasal surgery. Benefit, however, has not been fully studied. The objective of this study was to evaluate the impact of an SNS in terms of performance of the surgical procedure and of surgeon satisfaction, in a prospective multicenter study.

MATERIALS AND METHODS

A multicenter prospective study included patients undergoing endoscopic endonasal surgery using the electromagnetic DigiPointeur® (DGP) SNS in 16 French hospitals. An observation form, completed by the surgeon immediately at end of procedure, included type of procedure, and any changes in strategy or extent of surgery related to use of the SNS. Surgeon satisfaction was rated on an analog scale, with self-assessment of stress experienced during the procedure.

RESULTS

The study included 311 patients operated on by 36 surgeons in 16 French hospitals. Ethmoidectomy was the most frequent procedure (90%); tumor resection was performed in 5.1% of cases. The SNS enabled more extensive surgery in 81% of cases, in particular by identifying and opening additional cells (57% of cases). Mean satisfaction was 8.6/10; surgeons reported decreased surgical stress thanks to the SNS in 95% of cases.

CONCLUSION

In this observational study, the use of an SNS increased the extent of surgery in 81% of cases, and had a positive impact on the stress perceived by the surgeon in 95% of cases.

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.

Emergency Department care of childhood epistaxis

OBJECTIVE

The aim of this review is to determine an efficient and safe primary strategy care for paediatric epistaxis.

DATA SOURCES

We searched PubMed and Cochrane databases for studies referenced with key words 'epistaxis AND childhood'. This search yielded 32 research articles about primary care in childhood epistaxis (from 1989 to 2015). Bibliographic references found in these articles were also examined to identify pertinent literature. We compared our results to the specific management of adult epistaxis classically described in the literature.

RESULTS

Epistaxis is one of the most common reasons for referral of children to a hospital ENT outpatient department. The bleeding usually originates from the anterior septum, as opposed to adults. Crusting, digital trauma, foreign bodies and nasal colonisation with Staphylococcus aureus have been suggested as specific nosebleed factors in children. Rare aetiologies as juvenile nasopharyngeal angiofibroma appear later during adolescence. There are different modes of management of mild epistaxis, which begin with clearing out blood clots and bidigital compression. An intranasal topical local anaesthetic and decongestant can be used over 6 years of age. In case of active bleeding, chemical cauterisation is preferred to anterior packing and electric cauterisation but is only feasible if the bleeding site is clearly visible. In case of non-active bleeding in children, and in those with recurrent idiopathic epistaxis, antiseptic cream is easy to apply and can avoid 'acrobatic' cauterisation liable to cause further nasal cavity trauma.

CONCLUSIONS

Aetiologies and treatment vary with patient age and the existence or not of active bleeding at the time of the examination. Local treatments are usually easy to perform, but physicians have to ponder their indications depending on the possible complications in order to inform parents and to know paediatric epistaxis specificities.

[Nasally delivered drugs (corticosteroids and vaccines), ultra long-acting bronchodilators and inhaled therapies in an animal model]

Inhaled therapies are widely prescribed. Several aspects of these treatments were considered during the 4th meeting of the aerosol therapy workgroup (GAT) of the French-speaking respiratory society (Société de pneumologie de langue française [SPLF]). In this report, will be detailed the medications delivered by the nasal route, particularly corticosteroids and vaccines as well as the ultra long-acting beta2-agonists, and inhaled therapies for asthma due to allergy to cat dander.

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.

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.

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.

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.

Oxidative stress induces unfolding protein response and inflammation in nasal polyposis

BACKGROUND

Nasal polyposis, a chronic inflammatory disease affecting the upper airways, is a valuable and accessible model to investigate the mechanisms underlying chronic inflammation. The main objective of this study was to investigate a potential involvement of the unfolded protein response (UPR) in the context of oxidative stress and inflammation in nasal epithelial cells from nasal polyps (NP).

METHODS

Epithelial cells from NP (n = 20) and normal mucosa (Controls, n = 15) in primary culture were analyzed by global proteomic approach and cell biology techniques for the glucose-regulated protein 78 (GRP78), the spliced X-box-binding protein 1 (sXBP-1), the glucose-regulated protein 94 (GRP94), and the calreticulin (immunoblot, mass spectrometry, immunocytochemistry).

RESULTS

Proteomics analysis of human nasal epithelial cells in culture revealed the activation of the unfolded protein response in NP. Systematic cell biology and biochemical analysis of two markers (GRP78, sXBP-1) in the presence and absence of oxidative stress in NP showed a susceptibility of the unfolded protein response to oxidative stress compared to controls at least partially linked to an abnormal redox state of the protein disulfide-isomerase 4. This unfolded protein response was correlated with mitochondrial depolarization and secretion of interleukin 8 (IL-8) and leukotriene B4 (LTB4) and was prevented by mitochondrial antioxidant.

CONCLUSIONS

We show the existence of UPR in nasal epithelial cells that is linked to oxidative stress leading to IL-8 and LTB4 secretions. These mechanisms may participate in chronic inflammation in nasal polyposis.

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.

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.

Rhinitis and epistaxis in patients treated by anti-angiogenic therapy

Anti-angiogenic therapies have a particular drug-related toxicity profile including hypertension, thrombosis, haemorrhages, and proteinuria. Moreover, patients treated by angiogenesis inhibitors present nasal symptoms including symptomatic rhinitis and epistaxis. For the first time, a new entity of "atrophic rhinitis" induced by angiogenesis inhibitors is described and revealed that angiogenesis inhibitors alter the differentiation of nasal epithelium. VEGF may act on epithelial cell proliferation and differentiation in nasal epithelium.

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.

[Injury and epithelial wound healing: a pathophysiologic hypothesis for nasal and sinus polyposis]

Nasal polyposis (NP), asthma, and chronic bronchitis are chronic inflammatory diseases of the upper airways. They may be caused by injury to the respiratory epithelium in a chronic inflammatory environment. Several studies show that during NP nasal epithelial cells are involved in the overexpression of cytokines and growth factors. Among these, transforming growth factor beta1 (TGF-beta1) appears to play a major role in the genesis of NP. Differentiated respiratory epithelium, obtained from in vivo or in vitro models, is used to study wound healing in inflammatory environments, to elucidate the pathophysiology of NP, and to improve understanding and management of upper airway inflammatory diseases.

Transforming growth factor-beta1 increases airway wound repair via MMP-2 upregulation: a new pathway for epithelial wound repair?

In vivo, transforming growth factor (TGF)-beta1 and matrix metalloproteinases (MMPs) present at the site of airway injury are thought to contribute to epithelial wound repair. As TGF-beta1 can modulate MMP expression and MMPs play an important role in wound repair, we hypothesized that TGF-beta1 may enhance airway epithelial repair via MMPs secreted by epithelial cells. We evaluated the in vitro influence of TGF-beta1 on wound repair in human airway epithelial cells cultured under conditions allowing differentiation. The results showed that TGF-beta1 accelerated in vitro airway wound repair, whereas MMP inhibitors prevented this acceleration. In parallel, we examined the effect of TGF-beta1 on the expression of MMP-2 and MMP-9. TGF-beta1 induced a dramatic increase of MMP-2 expression with an increased steady-state level of MMP-2 mRNA, contrasting with a slight increase in MMP-9 expression. To confirm the role of MMP-2, we subsequently evaluated the effect of MMP-2 on in vitro airway wound repair and demonstrated that the addition of MMP-2 reproduced the acceleration of wound repair induced by TGF-beta1. These results strongly suggest that TGF-beta1 increases in vitro airway wound repair via MMP-2 upregulation. It also raises the issue of a different in vivo biological role of MMP-2 and MMP-9 depending on the cytokine microenvironment.

TGF-beta 1 downregulates CFTR expression and function in nasal polyps of non-CF patients

Nasal polyposis is a chronic inflammatory disease of the upper airways. It has been suggested that ion transports and CFTR expression could be modified in epithelial cells from nasal polyps of non-cystic fibrosis patients. We compared human nasal epithelial cells from nasal polyps (NP) with control nasal mucosa (CM). The level of CFTR mRNA was studied by Northern blot analysis and protein expression was studied by immunoprecipitation both ex vivo and in vitro in primary cultures of human nasal epithelial cells at the air-liquid interface. Ion transports were evaluated by short-circuit measurements in vitro. CFTR gene and protein expressions were significantly decreased in NP native tissues and in culture on day 4, when a global defect of ion transports was observed in NP cultures, but not in CM. We evaluated the effect of transforming growth factor (TGF)-beta 1 on CFTR expression and function in NP cultures on day 14 and showed, for the first time, that TGF-beta 1 was able to significantly downregulate the level of CFTR mRNA and cAMP-dependent current in NP cultures. Finally, we showed that the effects of TGF-beta 1 on ion transports could be reversed after 48-h removal of TGF-beta1 in NP cultures. In conclusion, our data strongly suggest that chronic inflammation in nasal polyposis downregulates CFTR gene and protein expression.

Atypical Sinusitis in Adults Must Lead to Looking for Cystic Fibrosis and Primary Ciliary Dyskinesia

HYPOTHESES/OBJECTIVES:: In adults, purulent pansinusitis or nasal polyposis starting early in life or that is permanently infected or associated either with chronic bronchial infection, infertility, or situs inversus are uncommon. In these atypical cases of chronic sinusitis (ACS), a primary dysfunction of the mucociliary clearance can be suspected. Adult patients with ACS were therefore investigated to detect primary ciliary dyskinesia (PCD) or cystic fibrosis (CF).

STUDY DESIGN

Open, prospective study.

PATIENTS AND METHODS

Forty-two patients with ACS were investigated with ciliary beat frequency and ultrastructure analysis in nasal cells and cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation analysis in blood leukocytes.

RESULTS

The diagnosis of PCD was confirmed in seven (17%) patients. At least one CFTR gene mutation was detected in 16 (38%) patients. The diagnosis of CF was suggested in three (7%) compound heterozygous patients. Another 13 (31%) patients were heterozygous for a CFTR gene mutation or a complex allele. Comparison of clinical features of ACS showed that only a family history of chronic sinusitis (P <.01) or chronic bronchitis (P <.02) and the presence of diffuse bronchiectasis (P <.0001) or serous otitis media (P <.0001) were significantly more frequent in PCD patients than in patients carrying CFTR gene mutations or those without PCD or CFTR gene mutations.

CONCLUSIONS

ACS should be considered a remarkable entity in which congenital abnormalities of epithelial cells are frequently detected (55% of patients). The higher frequency of mutations in ACS patients compared with the general population suggests that heterozygoty for CFTR gene mutation could be a sinusitis-causing status.

Computer-assisted analysis helps detect inner dynein arm abnormalities

The diagnosis of primary ciliary dyskinesia is based on demonstration of ciliary defects, mainly concerning dynein arms. Whereas the absence of outer dynein arms can be easily distinguished, the absence of inner dynein arms is difficult to confirm because of their low contrast on electron microscopy. Ciliary ultrastructure was studied in 40 patients suffering from respiratory tract infections. Conventional transmission electron microscopy showed normal cilia in 6 patients, confirmed a diagnosis of primary ciliary dyskinesia in 26 patients, and was inconclusive in 8 patients. All doubtful cases were related to inner dynein arm determination. Conventional electron microscopic analysis was able to define the ultrastructural phenotype of inner dynein arms in 40.5% of cases (6 presence of inner dynein arms, 13 absence of inner dynein arms). We developed computer-assisted analysis of electron microscopic micrographs to improve inner dynein arm visualization. Computer-assisted analysis consisted of image transformations designed to enhance the signal/noise ratio, based on the symmetry of ciliary axonemes. The sensitivity and specificity of computer-assisted analysis were 100 and 98%, respectively. The efficiency of computer-assisted analysis to visualize inner dynein arms, evaluated in the patients with undetermined phenotype after electron microscopy, was 86% (three normal cilia, seven primary ciliary dyskinesia with absence of outer dynein arms, three primary ciliary dyskinesia with absence of inner dynein arms, five partial absence of inner dynein arms). Computer-assisted analysis of ciliary micrographs improves the characterization of inherited axonemal defects.