Relationship between calcineurin inhibition and plasma endothelin concentrations in cyclosporine-A-treated kidney transplant patients

The inter-individual variability of cyclosporine (CsA) pharmacokinetics is well known. However, there is obviously also an inter-individual pharmacodynamic variability, which might be explored by the measurement of biomarkers of CsA effects. In 11 renal transplant patients, blood CsA concentrations, calcineurin inhibition in peripheral blood mononuclear cells and endothelin plasma concentrations were measured over a 4-h period after CsA intake. Mean plasma endothelin concentrations were higher than those of healthy subjects (3.66+/-0.46 pg ml(-1) versus 3.15+/-0.40 pg ml(-1), P