Valeric Acid, a Gut Microbiota Product, Penetrates to the Eye and Lowers Intraocular Pressure in Rats.

Mechanisms controlling intraocular pressure (IOP) and arterial blood pressure (BP) sharesimilar mediators, including gut bacteria metabolites. Here, we investigated the effects of valericacid (VA), a short chain fatty acid produced by microbiota from undigested carbohydrates, on IOPand BP. To test if gut VA penetrates to the eye we evaluated eyes' homogenates after theadministration of D9-VA into the colon. Additionally, the following experimental series wereperformed on 16-week-old Sprague Dawley rats to analyze the influence of VA on IOP: vehicletreatment; VA treatment; VA + hydroxybutyrate - a short chain fatty acids' G protein-coupledreceptor 41/43 (GPR 41/43) blocker (ANT); hydroxybutyrate; VA + angiotensin II; angiotensin II; VAtreatment in rats with superior cervical ganglion excision and sham operated rats. D9-VA rapidlypenetrated from the colon to the eye. VA significantly decreased IOP and BP. The decrease in IOPwas gradual and lasted through the experiment. In contrast, a decrease in BP was instantaneous andlasted no longer than 10 min. Angiotensin II, ANT, and sympathetic denervation did not influencethe effect of VA on IOP. In conclusion, colon-derived VA penetrates to the eye and decreases IOP.The effect is independent from BP changes, angiotensin II, GPR41/43, and sympathetic eyeinnervation.