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Haptoglobin genotype and endothelial function in diabetes mellitus: a pilot study
Lior Dayan1, Andrew P Levy, Shany Blum
1J. Recanati Autonomic Dysfunction Center, Medicine A, Technion-Israel Institute of Technology, Rambam Medical Center, PO Box 9602, 31096, Haifa, Israel. l_dayan@rambam.health.gov.il
European Journal of Applied Physiology
|April 7, 2009
Summary
Diabetic patients with the Haptoglobin (Hp) 2-2 genotype exhibit impaired endothelial function (EnF) compared to those with the Hp 1-1 genotype and healthy individuals. This suggests the Hp 2-2 genotype exacerbates endothelial dysfunction in diabetes.
Area of Science:
- Cardiovascular Research
- Genetics
- Metabolic Disorders
Background:
- Endothelial function (EnF) impairment in diabetes mellitus (DM) is linked to oxidative stress.
- Haptoglobin (Hp) is an antioxidant protein with two alleles (1 and 2); Hp 1 is a superior antioxidant to Hp 2.
Purpose of the Study:
- To investigate the hypothesis that DM individuals with the Hp 2-2 genotype experience greater endothelial dysfunction than those with the Hp 1-1 genotype.
Main Methods:
- Assessed EnF using post-ischemic reactive hyperemia and strain gauge plethysmography.
- Measured maximal flow and area under the flow-time curve (AUC) in 16 Hp 2-2 DM, 14 Hp 1-1 DM, and 14 healthy subjects.
- Matched DM patient groups for age, cardiovascular risk factors, and metabolic characteristics.
Main Results:
- Endothelial function indices (AUC and maximal flow) were significantly lower in the Hp 2-2 DM group compared to healthy and Hp 1-1 DM groups.
- Specific results: AUC (450 +/- 50 ml dl(-1)) and maximal flow (14 +/- 1.8 ml min(-1) dl(-1)) were lower in Hp 2-2 DM patients.
- P-values indicated statistical significance (P < 0.003 for AUC, P < 0.05 for maximal flow).
Conclusions:
- Diabetic patients with the Hp 2-2 genotype demonstrate worse endothelial function compared to healthy controls and diabetic patients with the Hp 1-1 genotype.
- The Hp 2-2 genotype may contribute to increased endothelial dysfunction in the context of diabetes mellitus.
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