Article: Longitudinal Testing of Retinal Blood Flow in a Mouse Model of Hypertension by Laser Speckle Flowgraphy
Authors: Michelle R Tamplin, Kimberly A Broadhurst, Anthony H Vitale, Ryuya Hashimoto, Randy H Kardon, Isabella M Grumbach
Journal: Transl Vis Sci Technol. 2021 Feb 5;10(2):16
Methods: Normotensive C57BL/6J mice were imaged by LSFG at one (n = 22) or three sessions (n = 10). Two additional cohorts were imaged by LSFG before, during, and after continuous infusion of angiotensin-II by minipump for 2 or 4 weeks (n = 6 and 8, respectively). Retinal blood flow, vascular resistance, and total area of retinal vascular flow, a surrogate of vascular remodeling and vasoconstriction, were determined at each time point.
Results: During infusion of angiotensin-II for 2 weeks, decreased retinal blood flow and area of vascular flow, as well as increased vascular resistance, were observed. These changes were reversed 1 week after the end of angiotensin-II infusion. In mice infused with angiotensin-II for 4 weeks, decreased retinal blood flow and increased vascular resistance persisted at 6 weeks postinfusion, despite a decrease in blood pressure.
Conclusions: Arterial hypertension, induced by continuous angiotensin-II infusion, results in reduced retinal blood flow, increased vascular resistance, and decrease in area of intravascular blood flow within retinal arterioles and venules. Sustained vasoconstriction 6 weeks after the end of a 4-week period of angiotensin-II infusion may indicate vascular remodeling after a period of chronic hypertension.
Translational relevance: Retinal LSFG is useful for serial investigation of blood flow in mouse models and provides a novel approach for translational studies on the microvascular effects of hypertension in vivo.
Link to journal online: https://tvst.arvojournals.org/article.aspx?articleid=2772275