Hydrophobic Molecules and Hemodialysis Treatment: ESRD as a Renohepatic Toxic State

Abstract

INTRODUCTION AND AIMS: Despite technological advances, the mortality of end-stage renal disease (ESRD) remains high. Uremic toxicity is due to a series of molecules, and not all of them are easily dialyzable. Several uremic hydrophobic toxins have classically been identified. Hydrophobic molecules (HPHM) are also present in the plasma of patients with several toxic syndromes. Fluorescence is a characteristic of many aromatic compounds. The total fluorescence of the hydrophobic fraction of plasma has been studied before and after hemodialysis in patients with ESRD. METHODS: Ten patients treated with a 3 times/week regimen of hemodialysis for ESRD were under study. Plasma samples were taken at the beginning and at the end of the dialytic process. One milliliter of plasma was extracted with 5 ml. of ether. Fluorescence of the ether fraction was determined with a digital filter fluorometer (excitation 300-400 nm. Emission >400 nm). The results were expressed in fluorescence arbitrary units (AU). Fivecontrol patients without renal insufficiency were also evaluated. RESULTS: The results are shown in Figures 1, 2 and 3. Five patients had a normal predialysis value (comparable to controls) of hydrophobic fluorescence (mean 15.2 AU, SD 1.9 AU) (Group A). In 5 patients, high values of fluorescence were recorded (mean 73.2 AU, SD 39.0 AU) (Group B). A definite, postdialysis decrease fluorescence was shown in only 2 patients in Group B. In all the other patients, no significant removal of HPHM was reported. CONCLUSIONS: In this preliminary study, two subpopulations of dialytic patients were identified. Fifty percent of patients show values compatible with a renohepatic toxic state(RHeTS). Hemodialysis has variable efficacy in the removal of different hydrophobic uremic toxins.