Serum levels of pigmentation markers are elevated in patients undergoing hemodialysis.

BACKGROUND

Diffuse hyperpigmentation is common among patients with chronic renal failure undergoing hemodialysis (HD). We have examined serum levels of 5-S-cysteinyldopa (5SCD, a pheomelanin precursor), pheomelanin, eumelanin, and protein-bound (PB-) 3,4-dihydroxyphenylalanine (DOPA) and PB-5SCD in HD patients.

METHODS

Pheomelanin and eumelanin were assayed by chemical degradation methods.

RESULTS

Serum levels of free 5SCD in HD patients (n = 16) were 9-fold higher than in healthy controls (n = 16). Levels of pheomelanin in HD patients were 2.6-fold higher than in controls, while levels of eumelanin did not differ between HD patients and controls. Levels of PB-DOPA and PB-5SCD in HD patients were approximately 1.5-fold higher than in controls. Serum levels of free 5SCD were positively correlated to the duration of HD therapy.

CONCLUSIONS

The high constitutive levels of free 5SCD, pheomelanin, and PB-DOPA in the blood may be deteriorating in HD patients through the production of reactive oxygen species.