The impact of lipoic acid on endothelial function and proteinuria in quinapril-treated diabetic patients with stage i hypertension

Journal of Cardiovascular Pharmacology and Therapeutics, 05/11/2012

In diabetic patients with hypertension, QUI reduces blood pressure, proteinuria, and improves endothelial function. Moreover, this effect is strongly potentiated with a combination of QUI and α–lipoic acid (ALA). These results may attenuate the progression of vascular pathophysiology seen in patients with a combination of diabetes and hypertension.


  • A total of 40 diabetic patients with Stage I hypertension were treated in a crossover double–blinded manner.
  • Patients were administered quinapril ([QUI] 40 mg/d) for 8 weeks or QUI + ALA (600 mg/d) for 8 weeks.
  • Measurements included blood pressure, 24–hour collection of urinary albumin, and endothelial–dependent flow–mediated dilation (FMD).


  • There was a change of metabolic parameters in both study groups after 8 weeks of therapy.
  • In comparison to baseline, the 24–hour urinary albumin significantly decreased by 30% in the QUI group (P = .018, time comparison) and 53% in QUI + ALA group (P < .005, time and group comparison).
  • Also, when compared with baseline, FMD significantly increased by 58% in QUI group (P < .005, time comparison) and by 116% in QUI + ALA group (P < .005, time and group comparison).
  • Systolic and diastolic blood pressure reduced significantly by 10% with QUI treatment.
  • There was no further blood pressure reduction when patients were administered both QUI and ALA.

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