Urinary L-valyl proline in patients with aortic aneurysms.

Recent evidence indicates that metabolism of elastin may be altered in patients with different types of infrarenal aortic disease and that the phenotypic expression of aortic disease may be dependent on the balance between aortic elastase and antiprotease activity. The dipeptide L-valyl proline (LVP) is a specific amino acid sequence for elastin and can be quantitated by high performance liquid chromatography analysis of the urine. This study was done to determine if alterations in systemic elastin metabolism could be detected in patients with different types of infrarenal aortic disease by quantitating urinary LVP. Patients were divided into one of five groups and had urine analyzed for LVP. These are control, no known aortic disease (n = 12); occlusive aortic disease (n = 10); elective abdominal aortic aneurysms (AAA) (n = 26); ruptured AAA (n = 5), and multiple aneurysms (n = 4). Urine values were correlated with aortic elastase and aortic antiprotease activity. Urinary LVP was significantly higher in patients with multiple aneurysms (1,209 micrograms per milliliter of urine) as compared with all of the other groups. Patients with elective AAA had significantly higher urinary LVP (40.5 micrograms per milliliter of urine) than patients with occlusive disease (9.1 micrograms per milliliter of urine) and those in the control group (4.2 micrograms per milliliter of urine). Patients with ruptured AAA did not have significantly elevated urinary LVP compared with other groups (18.6 micrograms per milliliter of urine). Urinary LVP increased significantly as aortic elastase and aortic elastase and antiprotease activity increased. These data suggest that elastin metabolism, as reflected by urinary LVP, is altered in patients with aortic aneurysmal disease and provide further evidence to support the concept that systemic elastin metabolism is altered in patients with different types of infrarenal aortic pathologic findings.