Abstract
Abstract 140: Vascular Structure in Brain: Lack of Small Vessel Recovery Following Hypertension
Stroke (1970), Vol.51(Suppl_1)
02/2020
DOI: 10.1161/str.51.suppl_1.140
Abstract
Vascular remodeling is a feature of small vessel disease (SVD), predictive of vascular events, brain injury, and cognitive decline. Hypertension alters vascular structure including diameter and cross-sectional area (CSA) of the vessel wall. While effects of hypertension on large arteries have been studied relatively widely, detailed quantification, including recovery from hypertension in microvessels, is rare. Previously, angiotensin II (Ang II)-dependent hypertension produced increased CSA but reduced internal diameter (ID) of cerebral arterioles (inward remodeling) in brain. Because cerebral arterioles are targets of SVD, we examined the hypothesis that brain microvessels can recover from hypertension after return of mean arterial pressure (MAP) to normal levels. MAP was measured using radiotelemetry in adult male C57BL6J mice at baseline, during infusion of vehicle or Ang II (1.4 mg/kg per day using osmotic mini-pumps) for 28 days, and during a 28 day recovery period (n=5 in each group). Prior to treatment, MAP was similar in both groups, with MAP remaining stable in vehicle treated mice. With Ang II treatment, MAP began to rise on day 3, steadily increasing until day 28. On day 30, MAP began to decrease, reaching levels seen with vehicle on days 46-47. In anesthetized mice, we measured pressure, diameter, and CSA of the vessel wall in maximally dilated arterioles (baseline diameter of 62±3 microns) at 1, 3, 7, 14, 28, and 56 days after pump implantation (n=7-9 in each group). At day 1, ID and CSA were similar in both groups. With vehicle, there was no significant change in CSA or ID at any time point. With Ang II, CSA increased at day 7 and was maintained at days 14 and 28 (P=0.023). ID did not change at day 3 or 7, but was reduced (by ~15%, P=0.011) at 14 and 28 days. During recovery (day 56), CSA returned 63% of the way to normal (compared to vehicle), while ID remained at day 14 and 28 values. In conclusion, CSA changed rapidly during hypertension onset and largely recovered with a reduction in MAP. Inward remodeling developed slowly and did not recover after return of MAP to control levels. The lack of recovery after hypertension has implications for the impact of SVD including hypoperfusion, impaired vasodilation, and augmented injury during ischemia.
Details
- Title: Subtitle
- Abstract 140: Vascular Structure in Brain: Lack of Small Vessel Recovery Following Hypertension
- Creators
- Gary Baumbach - Univ Iowa, Iowa City, IARasna Sabharwal - Univ Iowa, Iowa City, IAThomas Gerhold - Univ Iowa, Iowa City, IAMark Chapleau - Univ Iowa, Iowa City, IAFrank M Faraci - Univ Iowa, Iowa City, IA
- Resource Type
- Abstract
- Publication Details
- Stroke (1970), Vol.51(Suppl_1)
- DOI
- 10.1161/str.51.suppl_1.140
- ISSN
- 0039-2499
- eISSN
- 1524-4628
- Language
- English
- Date published
- 02/2020
- Academic Unit
- Molecular Physiology and Biophysics; Pathology; Neuroscience and Pharmacology; Cardiovascular Medicine; Internal Medicine; Iowa Neuroscience Institute
- Record Identifier
- 9984093783402771
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