The association between New Zealand Blackcurrant anthocyanins and airway inflammation, including PAI-1, in asthma: A placebo-controlled crossover feasibility study.

Asthma is a common chronic inflammatory airway disease. Plasminogen activator inhibitor 1 (PAI-1) contributes to airway inflammation, remodelling, disease severity, and exacerbations. As anthocyanins (ACN) possess antioxidant and anti-inflammatory properties, and oxidative stress is a key feature of asthma, investigating the efficacy of anthocyanin supplementation in this population is warranted. Although the study was originally designed to assess variability to plan a larger study in the event only five participants were recruited. The study design was a cross-over design. Participants received either a 300 mg ACN supplement or an identical placebo for eight weeks. Feasibility outcomes and asthma symptom control were assessed, alongside exploratory analyses of inflammatory markers, including fractional exhaled nitric oxide (FeNO) and salivary plasminogen activator inhibitor-1 (PAI-1). Associations between changes in PAI-1, Dietary Inflammatory Index (DII) scores, and the PAI-1 4G/5G polymorphism were also explored. Improvements in asthma symptom control were observed following ACN supplementation, including reduced daytime and nighttime symptoms and no activity limitation, similar to the placebo phase. Moreover, an absence of short-acting beta-agonist (SABA) reliever use N/N 0/5, 0%; SABA use reappeared during the placebo phase N/N 1/5, 20%. Preliminary findings support the feasibility of conducting a larger trial of ACN supplementation in adults with asthma. While ACN supplementation may have a positive effect on asthma symptom control, the findings are exploratory and require confirmation in adequately powered studies with larger sample sizes.