Idiopathic pulmonary fibrosis (IPF) is a type of scarring (fibrotic) lung disease. Reduced exercise capacity is a key symptom experienced by patients. In previous research the investigators identified that an interval-based exercise programme led to significant improvements in exercise capacity (Wallis et al Antioxidants. 2023).
An unexpected finding was that in patients with IPF, exercise led to a reduction in blood nitrite concentrations an observation the investigators did not see in non-affected individuals. Research has identified that nitrite concentrations are expected to increase after exercise and the size of this increase is related to an individual's exercise capacity. There is also evidence from healthy individuals and patients with chronic obstructive pulmonary disease (COPD) that nitrate supplementation (a source of nitrite) improves response to exercise training. However, in both these groups an exercise-induced fall in blood nitrite concentrations has not been observed. Hence our finding of an exercise-induced fall in blood nitrite levels in IPF patients suggest that they may be especially sensitive to supplementation with nitrate, commercially available as nitrate-rich beetroot juice (NRBJ).
This current study investigates this in a pilot placebo-controlled, double-blind, randomised, cross-over study of NRBJ on exercise capacity in IPF patients.
Aims In patients with IPF
* Quantify the effect of nitrate supplementation on exercise capacity * Determine the effect of nitrate supplementation on blood markers of nitric oxide production/metabolism. * Determine the effect of nitrate supplementation on forearm blood flow. Sample size: n=8 IPF patients, aged 18-85years and medical research breathlessness scale 1-3 Intervention: 3-days (two-times daily) NRBJ or nitrate-depleted placebo juice (both commercially available) with subsequent constant-load exercise test (Primary outcome). Following at least 1 week wash-out period participants will cross-over and repeat.
A cohort (n=8) of age, sex-matched controls without IPF will be enrolled for comparison of forearm blood flow and pre-exercise venous blood samples for biomarkers comparison only.
Number of sites: 1
Medical Research Council (MRC) breathlessness grade 1-3
Judged clinically stable for 3 months prior to recruitment by the investigator.
Baseline spirometry with FEV1/FVC ratio < 0.7.
Neoplastic disease undergoing treatment or active follow up.
Presence of infection or exacerbation requiring hospitalization, within last 3 months.
Current tobacco smoker or use of nicotine containing vapes (within 3 months)
Crossover
nitrate-rich beetroot juice (70ml with approx. 400 mg nitrate) twice a day for 3 days
Dietary supplementcommercially available beetroot juice dietary nitrate supplement
endurance time
fixed-load static cycle ergometry test
plasma nitrate and nitrite concentrations
venous blood samples
forearm blood flow
venous occlusion digital thermal imaging
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University Hospital Southampton NHS Foundation Trust
Lead sponsor
NIHR Southampton Respiratory Biomedical Research Centre
Collaborator
Asthma, Allergy and Inflammation Research (AAIR) Charity
Collaborator
