A Comparison of Cerebrospinal Fluid and Plasma Urotensin II Concentrations in Normotensive and Hypertensive Patients Undergoing Urological Surgery During Spinal Anesthesia: A Pilot Study

Abstract

UNLABELLED: Urotensin II is a novel endogenous vasoconstrictor. There are no data describing cerebrospinal fluid (CSF) concentrations in humans. Therefore, in this study, we aimed to quantify and compare plasma and CSF urotensin II concentrations in patients with essential hypertension and matched controls. Twenty male patients (10 receiving >6 mo of treatment for essential hypertension and 10 normotensive controls scheduled to undergo urological surgery under spinal anesthesia) were recruited into this single-blinded cohort study. Plasma and CSF urotensin II concentrations were measured by radioimmunoassay, along with mean arterial blood pressure (MAP), before admission, on the day of admission, and immediately before anesthesia. CSF and plasma urotensin II concentrations were low. Median (range) values in CSF for all 20 patients were significantly lower than plasma by approximately 15% (19.0 pg/mL [10.6-24.9 pg/mL] compared with 22.3 pg/mL [17.7-28.4 pg/mL]; P = 0.004). There were no significant differences between normotensive and hypertensive patients in either CSF or plasma concentrations. However, there was a significant positive correlation between average MAP and CSF urotensin II concentrations (r(2) = 0.44; P = 0.036) in the hypertensive group. IMPLICATIONS: Urotensin II is the most potent known endogenous human vasoconstrictor. In this pilot study, we report for the first time that cerebrospinal fluid levels are smaller than plasma levels and that there may be some association with increased blood pressure.