Preserved Relative Dispersion but Blunted Stimulation of Mean Flow, Absolute Dispersion, and Blood Volume by Insulin in Skeletal Muscle of Patients With Essential Hypertension
Key result
Essential hypertension in men was associated with significantly lower insulin-stimulated mean skeletal muscle blood flow compared to normotensive controls (2.3 vs 4.2 mL/0.1 kg/min, P<0.05).
Why the study?
Does insulin stimulation affect mean muscle blood flow, flow heterogeneity, and blood volume differently in patients with essential hypertension compared to normotensive controls?
Population
22 men, comprising 11 newly diagnosed, untreated mildly hypertensive men and 11 matched normotensive men.
Comparison
Normoglycemic hyperinsulinemic conditions vs Basal conditions and normotensive matched controls
Design
Case-control
Authors
Discussion
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Implication
Vascular insulin resistance may link hypertension to metabolic dysfunction; leaves open whether perfusion-targeted therapies improve outcomes.
Key Points
- This study aims to evaluate insulin's effects on blood flow, flow heterogeneity, and blood volume in individuals with essential hypertension.
- Participants included 11 newly diagnosed, untreated mildly hypertensive men and 11 matched normotensive men.
- Blood flow and volume were measured using positron emission tomography with specific tracers under fasting and hyperinsulinemic conditions.
- Bayesian iterative reconstruction algorithms enabled detailed pixel-by-pixel quantitation of blood flow.
- Insulin-stimulated glucose uptake was significantly lower in hypertensive men (41±4 μmol/kg/min) compared to normotensive men (59±4 μmol/kg/min, P<0.005).
- Skeletal muscle blood flow was significantly lower in hypertensives at baseline (1.7±0.2 vs. 2.7±0.4 mL/0.1 kg/min, P<0.05) and during hyperinsulinemia (2.3±0.2 vs. 4.2±0.8, P<0.05).
- The increase in muscle blood volume due to insulin was significant in normal subjects but not in hypertensive subjects, indicating insulin resistance.
Study Design
Type
Case-Control (n=22)
Structured PICO
Does insulin stimulation affect mean muscle blood flow, flow heterogeneity, and blood volume differently in patients with essential hypertension compared to normotensive controls?
P
Population
22 men (11 newly diagnosed, untreated mildly hypertensive and 11 matched normotensive), mean age 35, evaluated for insulin effects on muscle blood flow.
E
Exposure
Normoglycemic hyperinsulinemic conditions (insulin stimulation)
C
Comparator
Basal conditions (after an overnight fast) and normotensive matched controls
O
Outcome
Mean muscle blood flow, flow heterogeneity (dispersion), and blood volume measured by Positron emission tomographysurrogate
Main Result
Absolute Event Rate: 2.3% vs 4.2%
p-value: p=<0.05
Patients with essential hypertension exhibit blunted insulin-stimulated skeletal muscle blood flow, absolute dispersion, and blood volume, indicating vascular insulin resistance.
Cite This Study
Laine et al. (1998) conducted a case-control in Essential hypertension (n=22). Essential hypertension vs. Normotension was evaluated on Mean blood flow in skeletal muscle during hyperinsulinemia (p=<0.05). Essential hypertension in men was associated with significantly lower insulin-stimulated mean skeletal muscle blood flow compared to normotensive controls (2.3 vs 4.2 mL/0.1 kg/min, P<0.05).