Determination of Asymmetrical Dimethylarginine (ADMA) Accumulation in End Stage Renal Disease

Asymmetric dimethylarginine, ADMA, in plasma, is significantly elevated in patients with renal disease and associated with cardiovascular morbidity and mortality. We found that whole blood (WB) possesses the metabolic pathways required for both the generation and elimination of ADMA and we have developed ex vivo methods to assess the WB accumulation of ADMA in humans. The over-arching hypothesis is that dysregulation of ADMA metabolic pathways leads to greater ADMA whole blood content and greater capacity to accumulate ADMA, which 1) is not reflected by plasma levels and 2) is a better predictor of cardiovascular outcome than plasma levels in end-stage renal disease (ESRD). The following specific aims will be pursued to characterize whole blood ADMA in ESRD:

1. Compare and contrast baseline free plasma ADMA and total whole blood (free plus protein-incorporated) ADMA concentrations in ESRD patients, matched hypertensive controls and a normal population.
2. Determine the capacity of WB to accumulate (the net balance of generation and elimination) ADMA in ESRD patients, matched hypertensive controls and a normal population.

We will use state-of-the-art, high performance liquid chromatography techniques to measure ADMA levels in plasma and whole blood. Samples for ADMA measurements will be obtained from subjects with end-stage renal disease immediately before their dialysis treatments. Samples will also be obtained from volunteers without kidney disease. This group will be matched to the end-stage renal volunteers by age, gender and ethnicity. These volunteers will also be matched for the presence of hypertension and diabetes. The third group will consist of a normal population to measure the normal levels of ADMA and compare to the other two groups.

There is growing evidence to support a pathological role of ADMA in humans. These experiments will enhance our understanding of how ADMA is processed in the human body and how it is associated with kidney disease. Potentially, these results will lay the groundwork for new insights into the link between ADMA and the high cardiovascular disease burden in patients with kidney disease.