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Systemic hypertension produces pericyte changes in retinal capillaries
I H Wallow1, C D Bindley, D M Reboussin
1Department of Ophthalmology, University of Wisconsin, Madison 53792.
Investigative Ophthalmology & Visual Science
|February 1, 1993
Summary
Systemic hypertension causes retinal capillaries to constrict due to changes in pericytes, which have increased actin. This study provides the first in vivo morphologic evidence of pericyte contractility in retinal vascular disease.
Area of Science:
- Ophthalmology
- Cardiovascular Research
- Cell Biology
Background:
- Retinal capillaries are crucial for vision.
- Pericytes, cells surrounding capillaries, are suggested to be contractile.
- Systemic hypertension may reveal pericyte contractile function in retinal vasculature.
Purpose of the Study:
- To investigate retinal capillaries and their pericytes.
- To determine if pericyte contractility is evident in systemic hypertension.
- To explore the role of pericytes in regulating retinal blood flow under hypertensive stress.
Main Methods:
- Utilized ultrastructural morphometry and the myosin subfragment-1 technique.
- Examined retinal capillaries in normal and hypertensive rats.
- Collected data at three time points: early (24 wk), intermediate (44 wk), and late (68 wk).
Main Results:
- Hypertensive capillaries initially dilated, then constricted, and did not redilate.
- Increased wall thickness, pericyte coverage, and cytoplasm area were observed.
- Significant increases in pericyte actin filament bundles and actin area were noted at the intermediate time point.
Conclusions:
- Systemic hypertension impacts the retinal capillary bed.
- Pericyte changes, including actin increase, lead to capillary constriction.
- Morphologic criteria provide indirect in vivo evidence for pericyte contractility in retinal vascular disease.