Nasal Potential Difference in Cystic Fibrosis considering Severe<i>CFTR</i>Mutations

Ng, Ronny Tah Yen; Marson, Fernando Augusto Lima; Ribeiro, José Dirceu; Ribeiro, Antonio Fernando; Bertuzzo, Carmen Sílvia; Ribeiro, Maria Ângela Gonçalves de Oliveira; Severino, Silvana Dalgè; Sakano, Eulália

doi:10.1155/2015/306825

Cited by 9 publications

(9 citation statements)

References 42 publications

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“…From our archived human temporal bone collection at the University of Minnesota, we selected specimens for this study from deceased donors with a clinical diagnosis of CF by positive sweat test (sweat chloride value above 60 mEq/L [1, 10]). Excluded were specimens from donors who had tumors affecting the ear; who had leukemia; who underwent irradiation of the head and neck, chemotherapy, or any otologic surgery; who had clinical otosclerosis or a systemic autoimmune disease; or whose temporal bones were affected by processing artifacts.…”

Section: Methodsmentioning

confidence: 99%

Changes in the inner ear structures in cystic fibrosis patients

Pauna

Monsanto

Kurata

et al. 2017

International Journal of Pediatric Otorhinolaryngology

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Objective Although prolonged use of antibiotics is very common in cystic fibrosis (CF) patients, no studies have assessed the changes in both cochlear and peripheral vestibular systems in this population. Methods We used human temporal bones to analyze the density of vestibular dark, transitional, and hair cells in specimens from CF patients who were exposed to several types of antibiotics, as compared with specimens from an age-matched control group with no history of ear disease or antibiotic use. Additionally, we analyzed the changes in the elements of the cochlea (hair cells, spiral ganglion neurons, and the area of the stria vascularis). Data was gathered using differential interference contrast microscopy and light microscopy. Results In the CF group, 83% of patients were exposed to some ototoxic drugs, such as aminoglycosides. As compared with the control group, the density of both type I and type II vestibular hair cells was significantly lower in all structures analyzed; the number of dark cells was significantly lower in the lateral and posterior semicircular canals. We noted a trend toward a lower number of both inner and outer cochlear hair cells at all turns of the cochlea. The number of spiral ganglion neurons in Rosenthal’s canal at the apical turn of the cochlea was significantly lower; furthermore, the area of the stria vascularis at the apical turn of the cochlea was significantly smaller. Conclusions Deterioration of cochlear and vestibular structures in CF patients might be related to their exposure to ototoxic antibiotics. Well-designed case-control studies are necessary to rule out the effect of CF itself.

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Section: Methodsmentioning

confidence: 99%

Changes in the inner ear structures in cystic fibrosis patients

Pauna

Monsanto

Kurata

et al. 2017

International Journal of Pediatric Otorhinolaryngology

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“…The function and/or presence of the CFTR protein has been demonstrated in the sweat glands by measurement of ion concentrations in sweat [sweat test (ST) and evaporimeter] ( 2 – 5 ), nasal epithelium (nasal potential difference) ( 6 ), salivary gland (ions in saliva) ( 7 ), and in the digestive tract (presence and function of the CFTR protein in rectal biopsy) ( 8 , 9 ). Although CFTR gene mutations are the most important and appropriate markers for CF diagnosis, the analysis of ion chloride concentration in sweat is still considered the gold standard for the diagnosis, as well as the simplest method used to assess functional properties of the CFTR protein.…”

Section: Introductionmentioning

confidence: 99%

Thirty Years of Sweat Chloride Testing at One Referral Center

et al. 2017

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ObjectiveTo conduct a descriptive analysis of the sweat test (ST), associating ST results with epidemiological data, CFTR (cystic fibrosis transmembrane conductance regulator) mutations and reasons to indicate the ST, as well as correlating sweat sodium and sweat chloride concentrations in subjects.MethodsRetrospective survey and descriptive analysis of 5,721 ST at a university referral center.ResultsThe inclusion of the subjects was based on clinical data related with cystic fibrosis (CF) phenotype. The samples were grouped by (i) sweat chloride concentrations (mEq/L): <30: 3,249/5,277 (61.6%); ≥30 to <60: 1,326/5,277 (25.1%); ≥60: 702/5,277 (13.3%) and (ii) age: (Group A––GA) 0 to <6 months; (Group B––GB) ≥6 months to <18 years; (Group C––GC) ≥18 years. Digestive symptoms showed higher prevalence ratio for the CF diagnosis as well as association between younger age and higher values of sweat chloride, sweat sodium, and chloride/sodium ratio. The indication of ST due to respiratory symptoms was higher in GB and associated with greater age, lower values of sweat chloride, sweat sodium, and chloride/sodium ratio. There was higher prevalence of ST with sweat chloride levels <30 mEq/L in GB, ≥60 mEq/L in GC, and with borderline level in GB. There was positive correlation between sweat sodium and sweat chloride. Sweat chloride/sweat sodium and sweat sodium–sweat chloride indexes showed association with sex, reason for ST indication, and CFTR mutations. Sex alters some values presented in the ST. The number of ST/year performed before and after the newborn screening implementation was the same; however, we observed a higher number of borderlines values. A wide spectrum of CFTR mutation was found. Severe CFTR mutations and F508del/F508del genotype were associated with highest probability of ST chloride levels ≥60 mEq/L, and the absence of CFTR mutations identified was associated with borderline ST and respiratory symptoms.ConclusionsST data showed wide variability dependent on age, sex, reason for examination indication, CFTR mutations, and weight of the collected sweat sample. Sweat sodium concentration is directly correlated with sweat chloride levels and it could be used as a quality parameter.

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“…Analysis of ST alone may be insufficient to diagnose CF. Therefore; additional tests should be performed, such as nasal potential difference measurement, assessment of CFTR function in rectal biopsies, and evaporimetry [6–9]. Patients with CF usually have low sodium conductance, and consequently, elevated sodium concentration in sweat.…”

Section: Introductionmentioning

confidence: 99%

Quality of sweat test (ST) based on the proportion of sweat sodium (Na) and sweat chloride (Cl) as diagnostic parameter of cystic fibrosis: are we on the right way?

et al. 2016

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BackgroundTo assess the quality of sweat test (ST) based on the proportion of sweat sodium and sweat chloride as diagnostic parameter of cystic fibrosis (CF).MethodsA retrospective study of 5,721 sweat samples and subsequent descriptive analysis were carried out. The test was considered “of good quality” (correct) when: (i) sweat chloride was lower than 60 mEq/L, and sweat sodium was higher than sweat chloride; (ii) sweat chloride was higher than 60 mEq/L, and sweat sodium was lower than sweat chloride.ResultsThe study included 5,692/5,721 sweat samples of ST which had been requested due to clinical presentations compatible with CF and/or neonatal screenings with altered immunoreactive trypsinogen values. Considering the proportion of sweat sodium and sweat chloride as ST quality parameter, the test was performed correctly in 5,023/5,692 (88.2 %) sweat samples. The sweat chloride test results were grouped into four reference ranges for chloride (i) chloride < 30 mEq/L: 3,651/5,692 (64.1 %); (ii) chloride ≥ 30 mEq/L to < 40 mEq/L: 652/5,692 (11.5 %); (iii) ≥ 40 mEq/L to < 60 mEq/L: 673/5,692 (11.8 %); (iv) ≥ 60 mEq/L: 716/5,692 (12.6 %). In the comparative analysis, there was no association between ST quality and: (i) symptoms to indicate a ST [respiratory (p = 0.084), digestive (p = 0.753), nutritional (p = 0.824), and others (p = 0.136)], (ii) sweat weight (p = 0.416). However, there was a positive association with: (i) gender, (ii) results of ST (p < 0.001), (iii) chloride/sodium ratio (p < 0.001), (iv) subject’s age at the time of ST [grouped according to category (p < 0.001) and numerical order (p < 0.001)]. For the subset of 169 patients with CF and two CFTR mutations Class I, II and/or III, in comparative analysis, there was a positive association with: (i) sweat chloride/sodium ratio (p < 0.001), (ii) sweat chloride values (p = 0.047), (iii) subject’s age at the time of the ST grouped by numerical order (p = 0.001).ConclusionsConsidering that the quality of ST can be assessed by levels of sweat sodium and sweat chloride, an increasing number of low-quality tests could be observed in our sweat samples. The quality of the test was associated with important factors, such as gender, CF diagnosis, and subjects’ age.

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Nasal Potential Difference in Cystic Fibrosis considering SevereCFTRMutations

Cited by 9 publications

References 42 publications

Changes in the inner ear structures in cystic fibrosis patients

Changes in the inner ear structures in cystic fibrosis patients

Thirty Years of Sweat Chloride Testing at One Referral Center

Quality of sweat test (ST) based on the proportion of sweat sodium (Na) and sweat chloride (Cl) as diagnostic parameter of cystic fibrosis: are we on the right way?

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