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

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. © 2015 inbal dahan et al.