Non-asthmatic patients show increased exhaled nitric oxide concentrations

Effect of General Anesthesia Maintenance with Propofol or Sevoflurane on Fractional Exhaled Nitric Oxide and Eosinophil Blood Count: A Prospective, Single Blind, Randomized, Clinical Study on Patients Undergoing Thyroidectomy

Background: Nitric oxide (NO) is considered a means of detecting airway hyperresponsiveness, since even non-asthmatic patients experiencing bronchospasm intraoperatively or postoperatively display higher levels of exhaled NO. It can also be used as a non-invasive biomarker of lung inflammation and injury. This prospective, single-blind, randomized study aimed to evaluate the impact of two different anesthesia maintenance techniques on fractional exhaled nitric oxide (FeΝO) in patients without respiratory disease undergoing total thyroidectomy under general anesthesia. Methods: Sixty patients without respiratory disease, atopy or known allergies undergoing total thyroidectomy were randomly allocated to receive either inhalational anesthesia maintenance with sevoflurane at a concentration that maintained Bispectral Index (BIS) values between 40 and 50 intraoperatively or intravenous anesthesia maintenance with propofol 1% targeting the same BIS values. FeΝO was measured immediately preoperatively (baseline), postoperatively in the Postanesthesia Care Unit and at 24 h post-extubation with a portable device. Other variables measured were eosinophil blood count preoperatively and postoperatively and respiratory parameters intraoperatively. Results: Patients in both groups presented lower than baseline values of FeΝO measurements postoperatively, which returned to baseline measurements at 24 h post-extubation. In the peripheral blood, a decrease in the percentage of eosinophils was demonstrated, which was significant only in the propofol group. Respiratory lung mechanics were better maintained in the propofol group as compared to the sevoflurane group. None of the patients suffered intraoperative bronchospasm. Conclusions: Both propofol and sevoflurane lead to the temporary inhibition of NO exhalation. They also seem to attenuate systemic hypersensitivity response by reducing the eosinophil count in the peripheral blood, with propofol displaying a more pronounced effect and ensuring a more favorable mechanical ventilation profile as compared to sevoflurane. The attenuation of NO exhalation by both agents may be one of the underlying mechanisms in the reduction in airway hyperreactivity. The clinical significance of this fluctuation remains to be studied in patients with respiratory disease.

An official JRS statement: The principles of fractional exhaled nitric oxide (FeNO) measurement and interpretation of the results in clinical practice

Nitric oxide (NO) is produced in the body and has been shown to have diverse actions in the abundance of research that has been performed on it since the 1970s, leading to Furchgott, Murad, and Ignarro receiving the Nobel Prize in Physiology or Medicine in 1998. NO is produced by nitric oxide synthase (NOS). NOS is broadly distributed, being found in the nerves, blood vessels, airway epithelium, and inflammatory cells. In asthma, inflammatory cytokines induce NOS activity in the airway epithelium and inflammatory cells, producing large amounts of NO. Measurement of fractional exhaled nitric oxide (FeNO) is a simple, safe, and quantitative method of assessing airway inflammation. The FeNO measurement method has been standardized and, in recent years, this noninvasive test has been broadly used to support the diagnosis of asthma, monitor airway inflammation, and detect asthma overlap in chronic obstructive pulmonary disease (COPD) patients. Since the normal upper limit of FeNO for healthy Japanese adults is 37 ppb, values of 35 ppb or more are likely to be interpreted as a signature of inflammatory condition presenting features with asthma, and this value is used in clinical practice. Research is also underway for clinical application of these measurements in other respiratory diseases such as COPD and interstitial lung disease. Currently, there remains some confusion regarding the significance of these measurements and the interpretation of the results. This statement is designed to provide a simple explanation including the principles of FeNO measurements, the measurement methods, and the interpretation of the measurement results.

Long noncoding RNA PAGBC contributes to nitric oxide (NO) production by sponging miR-511 in airway hyperresponsiveness upon intubation

BACKGROUND AND OBJECTIVES

In this study, we aimed to study the molecular mechanisms underlying the symptoms of hyperresponsiveness during intubation.

METHOD

The value of circulating long noncoding RNA (lncRNA)-prognosis-associated gallbladder cancer (PAGBC) in the prediction of hyperresponsiveness upon intubation during general anesthesia was evaluated via the receiver operating characteristic analyses of serum miR-511, serum PAGBC, and serum nitric oxide (NO). In addition, the possible association between lncRNA-PAGBC/NOS1 messenger RNA (mRNA) and miR-511 was further validated via real-time quantitative polymerase chain reaction, immunohistochemistry assay, computational analysis, and luciferase assay. Enzyme-linked immunosorbent assay and Western blot analysis were also conducted to establish the regulatory relationship among PAGBC, miR-511, and NO synthase 1 (NOS1).

RESULTS

Compared with circulating miR-511 and serum NO, circulating PAGBC was associated with a higher predictive value. In addition, a negative correlation was found between serum miR-511 and serum PAGBC (multicorrelation coefficient: -0.5) as well as between serum miR-511 and serum NO (multicorrelation coefficient: -0.6). In addition, both lncRNA-PAGBC and NO were decreased in patients with hyperresponsiveness, whereas the levels of miR-511 and NOS1 in these patients were similar to those in normal patients. Furthermore, our computational analyses and luciferase assays validated the direct binding between miR-511 and lncRNA-PAGBC, whereas NOS1 mRNA was identified as a virtual target gene of miR-511. Moreover, in the presence of lncRNA-PAGBC, we also observed an evident increase in the levels of NOS1 and NO accompanied by an obvious decrease of miR-511 expression.

CONCLUSION

LncRNA-PAGBC downregulated the expression of miR-511, which in turn upregulated the expression of NOS1 mRNA and led to the increase in NOS1 expression, thus leading to the inhibited responsiveness (normal-responsiveness rather than hyperresponsiveness) to intubation in patients.

Can inflammatory markers in induced sputum be used to detect phenotypes and endotypes of pediatric severe therapy-resistant asthma?

BACKGROUND

The phenotypes and endotypes of severe therapy-resistant asthma (STRA) have not been fully elucidated in children. The aim of the present study was to investigate inflammatory markers in the induced sputum of children with STRA and to compare them with those present in a group of children who achieved control.

METHODS

A prospective cohort of children (6-18 years of age) diagnosed with severe asthma (GINA criteria) who had undergone treatment for at least 6 months was comprehensively followed for 3 months. Inhalation technique, adherence to treatment, ACT score, and main comorbidities were assessed. Induced sputum samples were collected for cytology analysis and quantitative assessment of cytokines; the participants also underwent spirometry, plethysmography, and fractional exhaled nitric oxide (FeNO) measurement.

RESULTS

Forty patients were included (average age 12.8 years; 62.5% male); of these, 13 (32.5%) were classified as STRA at the end of follow-up. There were no significant differences between the STRA and control groups in demographic data, functional test results, or FeNO levels. The eosinophilic inflammatory pattern predominated in both groups; however, the STRA group showed a proportionally higher percentage of sputum neutrophils (P < 0.05). The median sputum levels of the cytokines IL-10, GM-CSF, IFN-γ, and TNF-α were significantly higher in the STRA group (P < 0.05). GM-CSF and TNF-α levels showed inverse correlations with ACT scores.

CONCLUSION

The presence of neutrophils, the cytokines IL-10, and IFN-γ and, more particularly, TNF-α, and GM-CSF in the sputum may play an important role in the pathophysiological mechanism of STRA in children and adolescents. Specific antagonists for these cytokines may represent a future therapeutic strategy.

Evaluation of articles on pulmonology published in Brazilian journals other than the Brazilian Journal of Pulmonology

In Brazil, research on pulmonology has become increasingly more visible in recent years. In addition to the Brazilian Journal of Pulmonology, other journals have contributed to that by publishing relevant articles in this area. The objective of this article was to briefly report the most relevant studies on pulmonology that were published in other important Brazilian journals between 2009 and 2010. Altogether, there were 56 articles related to the various subareas that compose the field of respiratory diseases.