Inflammatory bowel disease (IBD) is associated with systemic inflammation that extends beyond the gastrointestinal tract, affecting organs such as the eye. This study investigates retinal hemodynamic changes in a mouse model of acute colitis induced by dextran sodium sulfate (DSS), with a focus on the role of angiotensin II and the potential of topical losartan administration to restore normal perfusion. Using intravital microscopy, we measured red blood cell velocities and vascular diameters in retinal arterioles and venules. DSS-treated mice exhibited a 30–40% reduction in retinal red blood cell velocity across both vessel types, leading to a significant 45% decrease in total retinal blood flow. In contrast, intraocular pressure remained unchanged, ruling out pressure-related mechanisms. Plasma angiotensin I/II levels were elevated by 67% in DSS mice, indicating activation of the renin-angiotensin system during intestinal inflammation. To assess whether angiotensin II contributes to retinal hypoperfusion, losartan was administered via eye drops prior to imaging. Topical losartan significantly attenuated the DSS-induced decline in blood flow, restoring retinal perfusion to approximately 60% of the lost volume. The treatment preserved arteriolar and venular shear rates near control values, suggesting improved vascular function.Fluralaner Data Sheet While arteriolar diameters showed no significant change, DSS mice exhibited a 10–15% reduction in venular diameter, which may have contributed to decreased shear rates. However, losartan prevented further deterioration, implying a direct vasodilatory effect. Concurrently, DSS caused a 35% drop in hematocrit, indicative of iron-deficiency anemia, which could predispose the retina to hypoxia. Despite reduced blood viscosity, retinal flow declined, highlighting the importance of active vasoconstriction over rheological factors. Notably, losartan had no effect on systemic hemodynamics, confirming its localized action when delivered topically.Olutasidenib Technical Information These findings demonstrate that angiotensin II plays a critical role in mediating remote ocular vascular dysfunction during colitis.PMID:34983293 The ability of a single application of eye-drop losartan to partially reverse retinal hypoperfusion suggests that targeting the ocular renin-angiotensin system may be a feasible strategy for preventing posterior eye complications in IBD patients. Future studies should evaluate long-term outcomes, including structural and functional recovery of the retina, and explore the potential of sustained topical therapy in chronic models of gut inflammation.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com