What is the clinical evidence from this study?

Study design: Other. Population: Hyperinsulinaemia (n=25). Intervention: Hyperinsulinaemia vs. Normoinsulinaemic controls. Primary outcome: Cardiac weight and haemodynamic regulation.

November 1, 1996European Journal of Clinical Investigation

The effects of hyperinsulinaemia on myocardial mass, blood pressure regulation and central haemodynamics in rats

Q: What question did this study set out to answer?

To evaluate the direct effects of isolated, long-term hyperinsulinaemia on myocardial mass, blood pressure regulation, and central haemodynamics in the absence of counter-regulatory autonomic responses.

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Key result

In rats, 7-week exposure to isolated hyperinsulinaemia increased left ventricular mass by 17% and total peripheral resistance (P<0.001), while lowering cardiac output and stroke volume by 30-40%.

Why the study?

Does isolated hyperinsulinaemia increase myocardial mass and alter haemodynamic regulation in rats?

Population

Rats after adrenalectomy with corticosterone substitution and continuous infusion of propranolol (n=25)

Comparison

Hyperinsulinaemia for 7 weeks vs Normoinsulinaemic adrenalectomized…

Design

Preclinical

Follow-up

7 weeks

Authors

ANAlexander NgUniversity College London NYNaoko YoshidaKeio University EJEva JennischeUniversity of Gothenburg

Discussion

Member takes

Implication

Potential contributor to myocardial remodeling in insulin-resistant states; leaves open translation to human disease.

Key Points

To evaluate the direct effects of isolated, long-term hyperinsulinaemia on myocardial mass, blood pressure regulation, and central haemodynamics in the absence of counter-regulatory autonomic responses.
Rats underwent adrenalectomy with corticosterone replacement and continuous propranolol infusion to block counter-regulatory pathways, then received hyperinsulinaemic treatment for 7 weeks (AIP group, n=15) with glucose drinking water to prevent hypoglycaemia, or served as normoinsulinaemic controls (AP group, n=10).
Blood pressure was assessed weekly by conscious tail-cuff plethysmography, followed by intra-arterial blood pressure and central haemodynamic measurements at the end of week 7.
Hyperinsulinaemic rats exhibited greater body weight and increased relative masses of the left ventricle (17%), right ventricle (20%), kidneys, and adipose tissues compared to controls.
Blood pressure remained stable for 5 weeks but significantly increased during weeks 6 and 7 in hyperinsulinaemic rats.
At week 7, total peripheral resistance doubled (P < 0.001) and cardiac output and stroke volume were 30–40% lower in hyperinsulinaemic rats than controls (P < 0.05), with no change in heart rate.

Structured PICO

Does isolated hyperinsulinaemia increase myocardial mass and alter haemodynamic regulation in rats?

Population

Rats after adrenalectomy with corticosterone substitution and continuous infusion of propranolol (n=25)

Intervention

Hyperinsulinaemia for 7 weeks (with glucose in drinking water to prevent hypoglycaemia)

Comparator

Normoinsulinaemic adrenalectomized, corticosterone- and propranolol-treated controls

Outcome

Cardiac weight and haemodynamic regulation (blood pressure, heart rate, total peripheral resistance, cardiac output, stroke volume)surrogate

Long-term exposure to isolated hyperinsulinaemia in rats leads to increased myocardial mass, elevated peripheral resistance, and decreased cardiac output, suggesting a direct trophic effect of insulin.

Cite This Study

Ng et al. (1996) studied Hyperinsulinaemia (n=25). Hyperinsulinaemia vs. Normoinsulinaemic controls was evaluated on Cardiac weight and haemodynamic regulation. In rats, 7-week exposure to isolated hyperinsulinaemia increased left ventricular mass by 17% and total peripheral resistance (P<0.001), while lowering cardiac output and stroke volume by 30-40%.

synapsesocial.com/papers/6a0df113fb8c7be8ffba8a03 https://doi.org/10.1046/j.1365-2362.1996.2880577.x

Topics

Hypertension management

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