January 22, 2010Journal of Applied Physiology
Exercise training normalizes ACE and ACE2 in the brain of rabbits with pacing-induced heart failure
Key result
Exercise training normalized the upregulation of ACE and downregulation of ACE2 in brain regions regulating autonomic function in rabbits with pacing-induced heart failure.
Why the study?
Does exercise training normalize ACE and ACE2 expression in the brain of rabbits with pacing-induced heart failure?
Population
New Zealand White rabbits with pacing-induced heart failure
Comparison
Exercise training (EX) vs No exercise training (sedentary CHF or sham)
Design
Preclinical
Authors
Discussion
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Implication
Hypothesis-generating for exercise effects on brain RAS in HF models; human trials needed before any clinical inference.
Structured PICO
Does exercise training normalize ACE and ACE2 expression in the brain of rabbits with pacing-induced heart failure?
P
Population
55 male New Zealand White rabbits with pacing-induced chronic heart failure or sham operation, subjected to 3 weeks of exercise training.
I
Intervention
Exercise training (EX)
C
Comparator
No exercise training (sedentary CHF or sham)
O
Outcome
ACE and ACE2 protein and mRNA expression in brain regions (cortex, cerebellum, medulla, hypothalamus, PVN, NTS, RVLM)surrogate
Main Result
Absolute Event Rate: 0.4% vs 0.8%
p-value: p=<0.05
Exercise training reverses the imbalance of ACE and ACE2 in brain regions regulating autonomic function in an animal model of heart failure.
Limitations
- Immunofluorescence techniques were only able to detect ACE2 protein in the intracellular compartment, leaving interstitial space balance unclear.
- Peptides (ANG II and ANG-(1-7)) were not directly measured in the brain.
- Precise molecular mechanisms underlying the imbalance of ACE and ACE2 were not investigated.
- A low level of exercise was used to maintain consistency between normal and CHF rabbits, which may have prevented changes in other cardiac parameters.
Cite This Study
Kar et al. (2010) studied Pacing-induced chronic heart failure (n=55). Exercise training vs. Sedentary was evaluated on ACE protein expression in the RVLM (ratio to GAPDH) (p=<0.05). Exercise training normalized the upregulation of ACE and downregulation of ACE2 in brain regions regulating autonomic function in rabbits with pacing-induced heart failure.