CSAD and chronic kidney disease: The main strength of the present study is that it is the first to demonstrate by direct measurements in a rat model of CKD the hepatic depletion of CSAD, a key enzyme of taurine biosynthesis, accompanied by a marked reduction in the steady-state rate of appearance of taurine in the animals’ urine and a decrease in the taurine/sulphate excretion ratio (Fig. 1 and Table 3).