Nasal nitric oxide in cystic fibrosis with and without humming

Induction of nitric oxide via humming does not improve short-term cognitive performance or influence emotional processing

Nitric oxide (NO) is involved in a variety of biological functions including blood vessel dilation and neurotransmitter release. In animals, NO has been demonstrated to affect multiple behavioral outcomes, such as memory performance and arousal, whereas this link is less explored in humans. NO is created in the paranasal sinuses and studies show that humming releases paranasal NO to the nasal tract and that NO can then cross the blood brain barrier. Akin to animal models, we hypothesized that this NO may traverse into the brain and positively affect information processing. In contrast to our hypothesis, an articulatory suppression memory paradigm and a speeded detection task found deleterious effects of humming while performing the task. Likewise, we found no effect of humming on emotional processing of photos. In a fourth experiment, participants hummed before each trial in a speeded detection task, but we again found no effect on response time. In conclusion, either nasal NO does not travel to the brain, or NO in the brain does not have the expected impact on cognitive performance and emotional processing in humans. It remains possible that NO influences other cognitive processes not tested for here.

Elexacaftor/tezacaftor/ivacaftor improves nasal nitric oxide in patients with cystic fibrosis

BACKGROUND

In health, nitric oxide (NO) shows high concentrations in the upper airways, while nasal NO (nNO) is significantly lower in patients with sinonasal inflammation, such as people with cystic fibrosis (PwCF). In PwCF treated with elexacaftor/tezacaftor/ivacaftor (ETI; PwCF-ETI), clinical improvement of sinonasal symptoms and inflammation was observed. We therefore hypothesised that ETI may increase nNO in PwCF.

METHODS

25 PwCF-ETI underwent nNO measurement at baseline and after 3 to 24 months of ETI treatment. NNO was measured using velum closure (VC) techniques in cooperative patients and tidal breathing (TB) for all patients. As controls, 7 CF patients not eligible for ETI (PwCF-non ETI) and 32 healthy controls (HC) were also repeatedly investigated.

RESULTS

In PwCF-ETI, sinonasal symptoms, lung function parameters and sweat chloride levels improved from baseline to follow-up whereas there was no change in PwCF-non ETI and HC. NNO increased from a median (IQR) value at baseline to follow-up from 348.2 (274.4) ppb to 779.6 (364.7) ppb for VC (P < 0.001) and from 198.2 (107.0) ppb to 408.3 (236.1) ppb for TB (P < 0.001). At follow-up, PwCF-ETI reached nNO values in the normal range. In PwCF-non ETI as well as HC, nNO did not change between baseline and follow-up.

CONCLUSIONS

In PwCF-ETI, the nNO values significantly increased after several months of ETI treatment in comparison to baseline and reached values in the normal range. This suggests that nNO is a potential non-invasive biomarker to examine sinonasal inflammatory disease in PwCF and supports the observation of clinical improvement in these patients.

Phenotypes of Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a complex heterogeneous disease with different phenotypes and endotypes. Recent advances in our understanding of the pathogenetic mechanisms of CRS endotypes have led to the introduction of effective biologic agents for CRS management. Traditionally, CRS phenotypes have been divided into with or without nasal polyps depending on the presence of polyps. Although this classification does not reflect the various endotypes that are recently emerging, it is simple and easily recognized by clinicians. Other phenotypes of CRS are fungal rhinosinusitis (including invasive and noninvasive subtypes), infectious rhinosinusitis, aspirin-exacerbated respiratory disease, cystic fibrosis, pediatric CRS, and CRS associated with systemic diseases. This article reviews the diagnostic approaches and up-to-date treatment strategies for each CRS phenotype with the hope that a better understanding of endotypes will result in a more scientific understanding of phenotypes and precise, personalized treatments.

Measurement of Nasal Nitric Oxide in Chronic Rhinosinusitis and Its Relationship to Patient-Reported Outcome: A Longitudinal Pilot Study

OBJECTIVE

To assess whether nasal nitric oxide (nNO) levels differ between healthy and sick sinuses in chronic rhinosinusitis (CRS). A secondary aim was to assess whether nNO levels change after treatment of CRS and whether there is an association with radiological findings or symptoms.

METHOD

Three groups of 12 participants each were examined: patients with CRS without polyposis (CRS group), patients with symptoms of CRS but radiologically normal sinuses (symptoms-only), and healthy controls. Measurements of nNO were carried out using aspiration method and humming maneuver. All participants completed the Sino-Nasal Outcome Test (SNOT-22). A second nNO measurement was done after treatment in the CRS group (n = 9) and the healthy control group (n = 12).

RESULTS

Nasal NO did not differ between any of the groups with any of the measurement techniques. There was a trend toward lower nNO values in the CRS group compared with the symptoms-only group and healthy controls, but it did not reach statistical significance. The SNOT-22 demonstrated inferior values for the CRS and symptoms-only groups compared with the healthy controls. At follow-up, no statistically significant change was found for the nNO measurements in either group.

CONCLUSION

Irrespective of occluded or open ostiomeatal complexes, no statistically significant differences in nNO were found in CRS compared with healthy controls using aspiration and humming methods. Treatment of CRS improved sinus patency without accompanying a significant change in nNO. This study can therefore not conclude that nNO can be used as a diagnostic tool for CRS without polyposis.

Exhaled and nasal nitric oxide in relation to lung function, blood cell counts and disease characteristics in cystic fibrosis

BACKGROUND

Patients with cystic fibrosis (CF) have similar or lower exhaled nitric oxide (FeNO) and lower nasal nitric oxide (nNO) levels than controls. There are divergent results on alveolar NO (Calv_NO) concentrations in relation to CF. There are inconsistent results on correlation between different nitric oxide parameters and lung function and inflammation in CF.

AIM

To compare FeNO, Calv_NO and nNO levels between subjects with CF, asthma and healthy controls and to study whether these parameters are related to lung function, blood cell counts or clinical characteristics in CF patients.

MATERIAL AND METHODS

Measurements of FeNO at multiple exhalation flow rates, nNO and spirometry were done in 38 patients (18 adults) with CF. Blood cell counts and CF clinical characteristics were recorded. Thirty-eight healthy controls and 38 asthma patients, gender- and age-matched, were included as reference groups.

RESULTS

FeNO levels were lower in CF patients (7.2 [4.7-11.2] ppb) than in healthy controls (11.4 [8.3-14.6] ppb) and asthma patients (14.7 [8.7-24.7] ppb) (both p < 0.005). These differences were consistent in adults. No difference in Calv_NO was seen between the groups. nNO levels in CF patients (319 [193-447] ppb) were lower than in healthy controls (797 [664-984] ppb) and asthma patients (780 [619-961] ppb) (both p < 0.001). FeNO positively related to FEV₁ (rho = 0.51, p = 0.001) in CF patients and this was consistent in both adults and children. A negative correlation was found between FeNO and blood neutrophil counts (rho = -0.37, p = 0.03) in CF patients.

CONCLUSION

CF patients have lower FeNO and nNO and similar Calv_NO levels as healthy controls and asthma patients. Lower FeNO related to lower lung function in both adults and children with CF. Furthermore, in CF, lower FeNO also related to higher blood neutrophil counts.

Nasal nitric oxide in patients with inherited retinal dystrophies

BACKGROUND

Ciliopathies refer to a wide variety of diseases in which mutations in the genes encoding proteins involved in ciliogenesis or protein transport to the primary cilia play pathogenetic roles, and in such diseases, retinal involvement may be present. Nitric oxide (NO) plays an important role in airway physiology, including regulation of ciliary motility and host defense. In primary ciliary dyskinesia, a syndromic ciliopathy, nasal NO (nNO) levels were reported to be extremely low compared with controls, possibly reflecting molecular defects leading to structural and functional ciliary abnormalities. We investigated whether decreased nitric levels were also present in patients with retinal inherited dystrophies.

METHODS

Nasal NO was measured in a group of patients with syndromic and nonsyndromic inherited retinal dystrophies.

RESULTS

Patients with inherited retinal dystrophies, both syndromic and nonsyndromic, had mean nNO levels that were lower than healthy controls. Seven patients had particularly low levels of nNO: 3 patients with retinitis pigmentosa and 4 individual patients with Mainzer-Saldino syndrome, Bardet-Biedl syndrome, Usher syndrome, and cone-rod disease.

CONCLUSIONS

These findings provide evidence that there is an underlying abnormal ciliary function involving the nasal epithelium in some patients with inherited retinal dystrophies.

Establishing normative nasal nitric oxide values in infants

INTRODUCTION

Primary ciliary dyskinesia (PCD), a disease of impaired respiratory cilia motility, is often difficult to diagnose. Recent studies show low nasal nitric oxide (nNO) is closely linked to PCD, allowing the use of nNO measurement for PCD assessments. Nasal NO cutoff values for PCD are stratified by age, given nNO levels normally increase with age. However, normative values for nNO have not been established for infants less than 1 year old. In this study, we aim to establish normative values for nNO in infants and determine their utility in guiding infant PCD assessment.

METHODS AND RESULTS

We obtained 42 nNO values from infants less than 1 year old without a history of PCD or recurrent sinopulmonary disease. Using regression analysis, we estimated the mean age-adjusted nNO values and established a 95% prediction interval (PI) for normal nNO. Using these findings, we were able to show 14 of 15 infant PCD patients had abnormally low nNO with values below the 95% PI.

CONCLUSIONS

In this study we determined a regression model that best fits normative nNO values for infants less than 1 year old. This model identified the majority of PCD infants as having abnormally low nNO. These findings suggest nNO measurement can help guide PCD assessment in infants, and perhaps other pulmonary diseases with a link to low nNO. With early assessments, earlier clinical intervention may be possible to slow disease progression and help reduce pulmonary morbidity.

Clinical application of nasal nitric oxide measurement in pediatric airway diseases

Nitric oxide plays an important role in several physiological and pathophysiological processes in the respiratory tract. Different ways to measure nasal nitric oxide levels in children are currently available. The possibility of obtaining nasal nitric oxide measurement from relatively young children, combined with the availability of portable devices that can be used even in the office setting, opens new perspectives for nasal nitric oxide analysis in the pediatric daily practice. This review presents a synopsis about the current clinical applications of nasal nitric oxide measurement in the pediatric clinical practice. A total of 3,775 articles on the topic were identified, of which 883 duplicates were removed, and 2,803 were excluded based on review of titles and abstracts. Eighty-nine full text articles were assessed for eligibility and 32 additional articles were obtained from the reference lists of the retrieved studies. Since very low nasal nitric oxide levels are found in the majority of patients with primary ciliary dyskinesia, most publications support a central role for nasal nitric oxide to screen the disease, and indicate that it is a very helpful first-line tool in the real-life work-up in all age groups. Decreased nasal nitric oxide concentration is also typical of cystic fibrosis, even though nasal nitric oxide is not as low as in primary ciliary dyskinesia. In other upper airway disorders such as allergic rhinitis, rhinosinusitis, nasal polyposis, and adenoidal hypertrophy, clinical utility of nasal nitric oxide is still critically questioned and remains to be established. Since nNO determination is flow dependent, a general consensus from the major investigators in this area is highly desirable so that future studies will be performed with the same flow rate. A shared nNO methodology will enable to overcome the challenges that lie ahead in incorporating nNO measurement into the mainstream clinical setting of pediatric airway diseases.

A human study model for nitric oxide research in sinonasal disease

Sinus nitric oxide (NO) measurements present a novel and promising approach to help overcome difficulties and confounding variables associated with nasal NO measurements such as the nasal cycle, ostial patency, and individual contribution to total NO production of each sinus. Conflicting results reported on nasal NO measurements in various sinonasal diseases are presumed to originate from the variable diffusion of sinus NO into the nose where it is measured. This study presents a novel technique and research method for direct measurement of sinus NO. The authors' original technique of individual, non-destructive catheterization of the sinuses through their natural ostia is developed and refined to allow accurate measurements of NO produced in the sinuses. Our study indicates that reproducible catheterization of the sinuses through their natural ostia can be performed in the clinical research setting under local and topical anesthesia. The model can be used to test the effects of various conditions on nasal and sinus NO production in a variety of disease models and the variables affecting sinonasal gas exchange can be differentially studied. Volunteer healthy adult human subjects without nasal allergies are used. An endoscopic nasal exam with topical anesthesia followed by in vitro allergy testing is performed to determine eligibility. Sinus computerized tomography (CT) scans are used to delineate anatomic features and to calculate paranasal sinus volumes. Continuous flow sinus air sampling and NO measurement with a chemiluminescence analyzer is obtained through polyethylene tube catheters (PEC) placed endoscopically into an aerated major paranasal sinus. Catheters are introduced through natural ostia under local and topical anesthesia. Nasal and differential sinus NO measurements are performed.

Measurement of nasal nitric oxide by hand-held and stationary devices

BACKGROUND

Nasal nitric oxide (nNO) is assessed by nasal aspiration/insufflation via one nostril or by nasal silent exhalation through a facemask and is also measured during humming, a manoeuvre that results in increased nNO in the presence of a patent osteomeatal complex. Humming nNO peak is absent in primary ciliary dyskinesia (PCD) and in cystic fibrosis (CF). Hand-held devices are used successfully for exhaled or nNO analysis. No study compared nNO during silent and humming exhalation using hand-held and stationary analysers.

METHODS

Thirty-eight subjects (14 PCD; 11 CF; 13 healthy individuals) measured nNO with a stationary and a hand-held analyser during silent and humming exhalations.

RESULTS

No difference between nNO obtained from stationary or hand-held analyser during silent and humming exhalation was found (P > 0·05). Patients with PCD exhibited lower silent and humming nNO than CF or controls (P < 0·001). During both silent and humming exhalation, there was a significant correlation between nNO from the two analyzers both in the whole study population and within each group (r ≥ 0·7, P < 0·01). Bland-Altman plots confirmed this agreement. Using the hand-held device during humming, nNO values of 50, 81 and 21 ppb had sensitivity and specificity > 90% for discriminating PCD or CF from healthy subjects, and patients with PCD from patients with CF, respectively.

CONCLUSIONS

The hand-held device is as effective as the stationary analyzer for assessing nNO during silent and humming exhalation. Its wider use might result in an increased number of subjects suspected to have PCD.

Diagnostic value of nasal nitric oxide measured with non-velum closure techniques for children with primary ciliary dyskinesia

OBJECTIVES

Nasal nitric oxide (nNO) is a reliable non-invasive screening test for primary ciliary dyskinesia (PCD), but the recommended technique, exhalation against resistance (ER), requires cooperation limiting its use in young children. Our objectives were to determine whether easier non-velum closure techniques have the ability to discriminate PCD and longitudinal reproducibility.

STUDY DESIGN

We conducted a case-control study evaluating 5 breathing techniques (ER, breath hold, tidal breathing mouth open, tidal breathing mouth closed, and humming) for measuring nNO in patients with PCD compared with control subjects (cystic fibrosis [CF], non-PCD non-CF bronchiectasis, and healthy). A subgroup repeated measurements 1 month later. Sensitivity, specificity, and intraclass correlation coefficient of each nNO technique were determined.

RESULTS

We tested 85 children (20 PCD, 32 CF, 14 broncheoctasis, and 19 healthy), aged 5 to 18 years (mean age, 11.5 years); 52% of children were male. All breathing techniques discriminated patients with PCD from control subjects with high specificity (>90%), 100% sensitivity, and intraclass correlation coefficient >0.8. nNO output cutoff values for diagnosing PCD varied with techniques (ER, 59 nL/min; breath hold, 61 nL/min; tidal breathing mouth open, 37 nL/min; tidal breathing mouth closed, 30 nL/min; humming, 41 nL/min).

CONCLUSION

Non-velum closure techniques are reproducible and valid to discriminate PCD; however, they generally yield lower values than ER.

Nasal nitric oxide and sinonasal disease: a systematic review of published evidence

OBJECTIVE

To critically and systematically review the data available on the sinonasal application of nasal nitric oxide measurement, particularly its use as a diagnostic, prognostic, or treatment effect indicator.

DATA SOURCES

EMBASE 1980 to February 10, 2010; Medline 1950 to February 10, 2010; Cochrane Collaboration database; NHS Evidence Health Information Resources database. Review Methods. The databases were searched using a search strategy designed to include manuscripts relevant both to nitric oxide measurement and sinus or nasal problems. A title search was carried out on these manuscripts to select those relevant to clinical or basic science aspects of nitric oxide measurement. A subsequent abstract search selected those manuscripts concerning the application of nitric oxide measurement to sinonasal problems. The manuscripts selected were subject to a full-text review to extract data sets of nasal nitric oxide readings for different patient groups.

RESULTS

Initially, 1088 manuscripts were selected. A title search found 335 manuscripts of basic scientific or clinical interest. An abstract search found 35 manuscripts directly relating to nitric oxide measurement in sinonasal disease. Full-text analysis produced 20 studies with extractable data on nasal nitric oxide levels in clearly defined patient groups. Studies did not show sufficient homogeneity to enable substantial meta-analysis of aggregated data.

CONCLUSION

Current evidence shows that nasal nitric oxide is not a clinically useful measure for sinonasal disease. Although there is some evidence that sinus surgery is associated with lowered nasal nitric oxide levels, there is no evidence that this is associated with deterioration in sinus health.

Documentation of the nasal nitric oxide response to humming: methods evaluation

RATIONALE

Nitric oxide (NO) is present at higher concentrations in the nasal cavity than in the lower airway, and at even higher concentrations within the paranasal sinuses proper. When the paranasal sinus ostia are patent, acoustic activity produced by vocalization with closed lips (humming) promotes mixing of sinus with nasal gases, producing a further increase in nasal NO. We wished to evaluate procedures for the documentation of the nasal NO response to humming.

MATERIALS AND METHODS

We compared two ATS-recommended sampling methods: 1) active exhalation of lower airway gas (parallel technique) and 2) passive aspiration of nasal gas with closed velopharynx (series technique). Variables controlled for included sampling rate, external resistance (parallel method), humming frequency, humming duration, and intertrial interval. Prior to upper airway sampling, exhaled lower airway NO was determined utilizing ATS-standardized technique.

RESULTS

Ten volunteers (seven males and three females, aged 21-58) with no history of respiratory allergies or sino-nasal disease were studied in a single session each. The parallel technique documented an increase in nasal NO during the humming manoeuvre in all subjects (mean ratio of humming-to-quiet NO, 4.2), whereas the series technique did so in eight of 10 subjects (mean ratio 2.1). Correcting for admixture from the lower airway, the ratio of humming-to-quiet NO was greater with the parallel than series sampling technique (P < 0.05).

CONCLUSIONS

Documentation of the response of nasal NO to humming in subjects without sino-nasal disease was consistently achievable by parallel sampling using commercially available equipment. Specific operational procedures are proposed.

Measurement of nasal nitric oxide

Nasal nitric oxide (nNO) is produced in high quantity in the upper airways. It is thought to be involved in host defence functions and regulation of mucociliary function, and to serve as a biochemical airborne transmitter. The measurement of nNO is easy and non-invasive. It has evolved as a screening test to exclude primary ciliary dyskinesia (PCD) in patients with suggestive symptoms, because nNO is extremely low in this condition. Nasal NO is also altered in other nasal, sinus and pulmonary pathologies, but is without diagnostic value outside of PCD.

Nitric oxide in the airways

PURPOSE OF REVIEW

This review briefly explains the basic facts about nitric oxide, which is entering clinical practice as a measure of lower airways inflammation and is likely also to be employed in otorhinolaryngological practice.

RECENT FINDINGS

These include the validity of nasal nitric oxide in diagnosing primary ciliary dyskinesia and in monitoring the response to chronic rhinosinusitis therapy. The nasal nitric oxide value combined with a humming manoeuvre, which increases the passage of nitric oxide from the sinuses to the nose if the ostiomeatal complex is patent, could reduce the need for computed tomography scans. The link between nitric oxide production and ciliary beating requires further exploration. Therapeutic adjustments to nitric oxide production are under investigation.

SUMMARY

Nitric oxide is likely to prove highly relevant to airways defence, as well as being an inflammatory mediator. Nasal nitric oxide probably explains some of the benefit of nasal rather than mouth breathing.