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Abstract
Objective There is preclinical evidence that consumption of berryfruit extract may reduce chronic airways inflammation and modify airway remodelling in allergen-induced models of lung inflammation. We investigated the effect of berryfruit extract on the fractional expired nitric oxide (FeNO), a biomarker of eosinophilic airways inflammation, in adults with steroid-naïve asthma.
Design Randomised placebo-controlled cross-over double-blind trial.
Setting Single-centre community-based trial.
Participants 28 steroid-naïve mild asthmatics with Feno >40 ppb, of whom 25 completed both study interventions.
Interventions Participants were randomised to receive, according to the cross-over design, 100 mg berryfruit polyphenolic extract (BFPE) or placebo for 4 weeks, with a 4-week washout period between the interventions.
Primary outcome measure The primary outcome variable was FeNO at 4 weeks, analysed by a mixed linear model, with a random effect for participant and baseline FeNo as a covariate.
Results The mean (SD) natural logarithm transformed (ln) FeNO after 4 weeks of treatment for the BFPE and placebo groups was 4.28 (0.47) and 4.22 (0.47), respectively. The paired change from baseline mean (SD) BFPE minus placebo ln FeNO was −0.03 (0.39), N=25. The mixed linear model estimate, with baseline covariate adjustment, difference in ln FeNO, was −0.002 (95% CI −0.15 to 0.14), p=0.98. This is equivalent to a ratio of geometric mean FeNO of 1.0 (95% CI 0.86 to 1.15).
Conclusions In steroid-naïve participants with mild asthma and elevated FeNO, there was no effect of BFPE on FeNO, a biomarker of eosinophilic airways inflammation. Caution is required in the extrapolation of apparent benefit in murine models of lung eosinophilia to clinical efficacy in patients with asthma.
Trial registration number ANZCTR: 12613000451707; Results.
- Animal models
- Clinical respiratory medicine
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Footnotes
Contributors RB, IB, JF, JH, MH, RH, MWe and MWi were involved in study concept and design. IB, RC-S, CM, JP, SP and MWi were involved in acquisition of data. RB, IB, SP and AS were involved in drafting of the manuscript. All authors were involved in critical revision of the manuscript for important intellectual content. MWe was involved in statistical analysis. All authors provided administrative, technical and material support. SP and MWi were involved in study supervision..
Funding This research was funded by a New Zealand Ministry of Business, Innovation and Employment Grant (Contract C11X1002), awarded to the New Zealand Institute of Plant and Food Research. The Medical Research Institute of New Zealand is supported by Health Research Council of New Zealand Independent Research Organisation funding (HRC 14/1002).
Competing interests None declared.
Ethics approval NZ Health and Disability Committee.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Patient-level data are available from the corresponding author on request. The presented data are anonymised and the risk of identification is low.