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Journal of Diabetes Research
Volume 2015, Article ID 613860, 7 pages
http://dx.doi.org/10.1155/2015/613860
Clinical Study

Interaction between the Haptoglobin 2 Phenotype and Diabetes Mellitus on Systolic Pulmonary Arterial Pressure and Nitric Oxide Bioavailability in Hemodialysis Patients

1Diabetic Nephropathy Laboratory, The Baruch Padeh Poriya Medical Center, Faculty of Medicine in the Galilee, 15208 The Lower Galilee, Israel
2Division of Nephrology & Hypertension, The Baruch Padeh Poriya Medical Center, Faculty of Medicine in the Galilee, 15208 The Lower Galilee, Israel
3Division of Vascular Medicine, Holy Family Hospital, 16234 Nazareth, Israel
4Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 31096 Haifa, Israel
5Department of Physics and Translational Science Center, Wake Forest University, Reynolda Campus, Winston-Salem, NC 27109, USA

Received 19 April 2015; Revised 22 May 2015; Accepted 26 May 2015

Academic Editor: Hiroshi Okamoto

Copyright © 2015 Inbal Dahan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Elevated systolic pulmonary artery pressure (s-PAP, ≥35 mmHg) serves as an independent predictor of mortality in hemodialysis (HD) and diabetic (DM) patients. A polymorphism in the antioxidant Haptoglobin (Hp) gene has been shown to regulate the bioavailability of nitric oxide (NO), a major mediator of pulmonary vascular tone. We therefore set out to test the hypothesis that the Hp polymorphism may be a determinant of developing elevated s-PAP specifically in the DM state due to a decreased bioavailability of NO. To test our hypothesis we Hp typed and performed transthoracic echocardiography on a series of HD patients and stratified them into elevated and normal s-PAP groups and then evaluated whether there was a significant association between the Hp type, elevated s-PAP, and decreased NO bioavailability as defined by low plasma nitrite. We found a statistically significant interaction between the Hp type and DM on the prevalence of elevated s-PAP and lower mean nitrite levels with the combination of elevated s-PAP and low nitrite levels being significantly more prevalent in Hp 2-2 DM individuals. We conclude that the Hp 2 type is associated with elevated s-PAP levels and low plasma nitrite levels in HD patients specifically in the DM state.