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Myocardial and Renal Renin-Angiotensin System Enzyme Activity in Dogs
Emma C Weitzhandler1, Marisa K Ames1, Machelle D Wilson2
1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, USA.
Journal of Veterinary Internal Medicine
|July 2, 2025
Summary
Renin-angiotensin system enzymes remain active in canine heart and kidney tissues for over 24 hours postmortem. This study quantifies tissue renin-angiotensin system enzyme activity in dogs, showing reliable results even with delayed freezing.
Area of Science:
- Veterinary Pathology
- Cardiovascular Research
- Renal Physiology
Background:
- Accurate quantification of the tissue renin-angiotensin system (RAS) is crucial for understanding cardiovascular and renal health.
- Existing methods for assessing tissue RAS activity face limitations, necessitating new approaches.
Purpose of the Study:
- To determine the activity of myocardial and renal renin-angiotensin system enzymes in postmortem canine tissues.
- To evaluate the impact of postmortem interval on the reliability of tissue RAS enzyme activity measurements.
Main Methods:
- Analysis of myocardial and renal tissues from 15 purpose-bred dogs with heartworm infection and 22 client-owned dogs.
- Tissue samples were collected at varying times postmortem (within 20 minutes to a median of 21.9 hours).
- Enzyme activity was assessed by incubating homogenized tissues with angiotensin I or II, measuring product formation under different conditions.
Main Results:
- Renin-angiotensin system enzymes demonstrated activity in all analyzed postmortem canine tissues.
- Angiotensin-converting enzyme was the primary contributor (>88%) to angiotensin II formation.
- Paired sample analysis indicated reliable enzyme activity measurements even with delayed freezing (up to 24 hours postmortem).
Conclusions:
- Canine myocardial and renal tissues retain active renin-angiotensin system enzymes for over 24 hours postmortem.
- These findings support the use of postmortem tissues for reliable renin-angiotensin system research.
- The study provides a foundation for further investigation into tissue RAS in various physiological and pathological conditions.
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