Do extracts of tomato suppress an overactive bladder phenotype?

BACKGROUND Overactive bladder (OAB) is a symptomatic disease characterised by increased bladder voiding, urinary urgency and can be with or without urinary incontinence. Prevalence increases with age and affects both men and women equally. OAB causes a severe impact on the quality of life and the cause remains unknown. The current mainstay treatment is anti-muscarinic drugs. They offer relief in some patients but have a number of side effects.

Anecdotal evidence suggests lycopene and β carotene, both found in tomatoes, can improve lower urinary tract symptoms. Tomatoes, due to their high acid content, are also recommended to be avoided in OAB.

OBJECTIVE To determine whether extracts found in tomatoes can suppress an OAB phenotype.

MATERIALS AND METHODS Isometric tension experiments to measure the effect of lycopene, β carotene and ascorbic acid on an OAB phenotype induced using carbachol. Different concentrations of each agent were tested.

RESULTS Lycopene reduced spontaneous contractions and induced a periodic relaxation. The effect was concentration dependent. Lycopene caused a reduction in basal tone and amplitude of spontaneous contractions. There was a statistically significant reduction with 6µM but not with 12µM.

Ascorbic acid had no significant effect on spontaneous contractions with increasing concentration.

β carotene caused a small change in spontaneous contractions. The effect was similar in the vehicle control in which β carotene was dissolved in.

CONCLUSIONS Lycopene causes a concentration-dependent relaxation and a reduction in spontaneous contractions. Ascorbic acid has little to no effect on spontaneous contractions. The effect of β carotene needs to be further explored.