Nasal and Oral Nitric Oxide Levels During Experimental Respiratory Syncytial Virus Infection of Adults

Abstract

Nitric oxide (NO) is a recognized mediator of inflammation in diseases affecting the lower respiratory tract, and has been implicated in the expression of viral upper respiratory tract infections. Here, exhaled nasal and oral NO concentrations and nitrite concentrations in nasal lavage fluids were measured, symptoms were scored and pulmonary function was evaluated before (Day 0) and after (Days 1-8) experimental exposure of 17 adult subjects to respiratory syncytial virus (RSV) type B. After exposure, RSV was recovered from 12 (70%) subjects by culture and/or specific antigen detection. Both subjects with and those without RSV recovery developed increased nasal and throat symptoms after RSV exposure, but none evidenced changes in the three measures of NO concentration. These results do not support the hypothesis of increased NO production during RSV infection and complement earlier studies that reported a lack of change in nasal NO concentration during experimental influenza and rhinovirus infections.

Respiratory Syncytial Virus Infection: Mechanisms of Redox Control and Novel Therapeutic Opportunities

“…In contrast to the in vitro and animal studies, adult volunteers experimentally infected with RSV (but not showing clinical signs of lower respiratory tract infection) did not demonstrate a change in nasal and oral NO production compared to control subjects (86). In addition, a reduction of exhaled NO has been reported in infants during the acute phase of RSV bronchiolitis, compared with healthy controls, which returned to normal levels during the convalescence phase (79).…”

Role of nasal nitric oxide in the resolution of experimental rhinovirus infection

“…Moreover, there are conflicting results regarding changes in eNO concentrations after viral infection, with some studies failing to detect changes in NO values either by means of direct measurement of the expired gases 4 or by means of indirect measurement of the oxidation products of NO: nitrite, nitrate, or both. 4,17 The present study followed the American Thoracic Society guidelines for measurement of eNO and monitored concentrations of NO from the lower airways and nose at 3 different low-flow rates. These measures allow the wall concentration of NO to be calculated by using a 3-point linear regression extrapolated to 0 flow.…”

“…Significant increases in eNO have also been observed on days 2 and 3 after experimental RV-16 infection and day 8 after inoculation of influenza but not during experimental infections with respiratory syncytial virus. 4 Although increases in eNO have been observed in some studies, the precise role of NO in the pathogenesis of upper respiratory viral infections has not been elucidated. This might be due in part to the fact that NO can be produced by almost all mammalian cells and can participate in many cellular and organ functions.…”

Effects of the Indoor Environment on the Fraction of Exhaled Nitric Oxide in School‐Aged Children

“…While a number of studies have suggested subject factors that can alter FeNO measurements obtained during standardized testing, such as recent exercise or respiratory tract infection, relatively few studies have been performed to investigate whether environmental factors can affect FeNO in children (9)(10)(11). We examined these issues in a relatively large number of children obtained from a population sample.…”