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Close relationship between sympathetic activation and coronary microvascular dysfunction during acute hyperglycemia

Yasuyoshi Takei1, Hirofumi Tomiyama, Nobuhiro Tanaka

  • 1Second Department of Internal Medicine, Tokyo Medical University, Japan.

Circulation Journal : Official Journal of the Japanese Circulation Society
|January 26, 2007
PubMed

Insights

Acute hyperglycemia during an oral glucose tolerance test impairs coronary microvascular function and increases oxidative stress and sympathetic activation in individuals with atherosclerotic risk factors.

Area of Science:

  • Cardiovascular Physiology
  • Metabolic Health
  • Vascular Biology

Background:

  • Coronary microvascular function is crucial for heart health.
  • Atherosclerotic risk factors may predispose individuals to vascular dysfunction.
  • The impact of acute hyperglycemia on coronary microvasculature requires further investigation.

Purpose of the Study:

  • To evaluate the effect of acute hyperglycemia (AHG) during an oral glucose tolerance test (OGTT) on coronary microvascular function.
  • To assess the associations between changes in coronary microvascular function, oxidative stress, and sympathetic tone.
  • To explore the relationship between AHG and these physiological markers in individuals with atherosclerotic risk factors.

Main Methods:

  • Transthoracic Doppler echocardiography and OGTT were performed in 24 subjects with atherosclerotic risk factors.
  • Coronary flow velocity during adenosine infusion (CFV(hyp)) was measured.
  • Plasma thiobarbituric acid-reactive substances (TBARS) and heart rate variability (LF/HF ratio) were assessed before and during OGTT.

Main Results:

  • Acute hyperglycemia significantly decreased coronary flow velocity (CFV(hyp)).
  • Plasma levels of oxidative stress markers (TBARS) and sympathetic tone (LF/HF ratio) increased.
  • Percent changes in CFV(hyp) were significantly associated with percent changes in the LF/HF ratio (beta=-0.43, p<0.05).

Conclusions:

  • In subjects with atherosclerotic risk factors, AHG induces coronary microvascular dysfunction, increased oxidative stress, and sympathetic activation.
  • Coronary microvascular dysfunction appears closely linked to sympathetic activation.
  • These findings highlight the detrimental effects of acute hyperglycemia on vascular health in at-risk populations.
Abstract

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