August 9, 2013American Journal of Hypertension

AT1 Receptors Prevent Salt-Induced Vascular Dysfunction in Isolated Middle Cerebral Arteries of 2 Kidney-1 Clip Hypertensive Rats

Q: What is the clinical evidence from this study?

Study design: Other. Population: 2 Kidney-1 Clip (2K1C) Goldblatt hypertension. Intervention: High salt diet and AT1 receptor blockade (losartan) vs. Normal salt diet and sham operation. Primary outcome: Vasodilation in response to acetylcholine and reduced PO2 in middle cerebral arteries.

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Key result

In 2K1C hypertensive rats, sustained elevated angiotensin II levels maintained endothelium-dependent vasodilation during a high salt diet via AT1 receptor-mediated preservation of antioxidant defenses.

Population

Male Sprague-Dawley rats subjected to 2 kidney-1 clip Goldblatt hypertension for 4 weeks and sham-operated…

Comparison

High salt diet for 3 days, AT1 receptor… vs Normal salt diet, untreated controls, or…

Design

Preclinical

Follow-up

4 weeks, 3 days, 1 week

Authors

ABA. M. Beyer KFKatherine FredrichMedical College of Wisconsin JLJulian H. LombardMedical College of Wisconsin

Discussion

Member takes

Implication

Does not support changes in hypertension management; leaves open angiotensin II's role in endothelial preservation for future human studies.

Structured PICO

Population

Male Sprague-Dawley rats aged 11-12 weeks subjected to 2K1C Goldblatt hypertension or sham operation to study cerebral vascular relaxation.

Intervention

High salt (4% NaCl) diet for 3 days, AT1 receptor blockade (losartan 20 mg/kg/day for 1 week), or low-dose ANG II infusion (5 ng/kg/min IV for 3 days).

Comparator

Normal salt (0.4% NaCl) diet, untreated controls, or sham-operated rats.

Outcome

Vasodilation of isolated middle cerebral arteries (MCA) in response to acetylcholine (ACh) and reduced partial pressure of oxygen (PO2).surrogate

In a high-renin rat model of hypertension, sustained elevated angiotensin II levels paradoxically maintain endothelium-dependent vasodilation during a high-salt diet via AT1 receptor-mediated preservation of antioxidant defenses.

Limitations

Use of small mesenteric arteries as a surrogate for SOD expression in the cerebral arteries.
Mechanisms other than preservation of antioxidant defenses could also contribute to the ability of AT1 receptor activation to preserve vascular function.
Use of small mesenteric arteries as a surrogate for SOD expression in cerebral arteries
Mechanisms other than preservation of antioxidant defenses could also contribute to the ability of AT1 receptor activation to preserve vascular function

Cite This Study

Beyer et al. (2013) studied 2 Kidney-1 Clip (2K1C) Goldblatt hypertension. High salt diet and AT1 receptor blockade (losartan) vs. Normal salt diet and sham operation was evaluated on Vasodilation in response to acetylcholine and reduced PO2 in middle cerebral arteries. In 2K1C hypertensive rats, sustained elevated angiotensin II levels maintained endothelium-dependent vasodilation during a high salt diet via AT1 receptor-mediated preservation of antioxidant defenses.

synapsesocial.com/papers/6a8adf100c58d86fb4ca9ffe https://doi.org/10.1093/ajh/hpt129

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Implication

Does not support changes in hypertension management; leaves open angiotensin II's role in endothelial preservation for future human studies.

AT1 Receptors Prevent Salt-Induced Vascular Dysfunction in Isolated Middle Cerebral Arteries of 2 Kidney-1 Clip Hypertensive Rats

Discussion

Member takes

Implication

Structured PICO

Limitations

Cite This Study

AT1 Receptors Prevent Salt-Induced Vascular Dysfunction in Isolated Middle Cerebral Arteries of 2 Kidney-1 Clip Hypertensive Rats

Discussion

Member takes

Implication

Structured PICO

Limitations

Cite This Study

Also Consider

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