Isolation and characterisation of human proximal tubular cells derived from kidney cortical segments

Abstract

1 Human renal proximal tubular cells (HPTC) were isolat ed by collagenase digestion and purified following fil tration and isopycnic Percoll density centrifugation. This method used cortical tissue obtained from surgical nephrectomies and was both rapid and simple, provid ing a preparation of cells with high viability (> 93 ± 3%) and recovery (16 ± 7 x 106 cells g^-1 of cortical tissue).

2 Characterisation of the isolated cells showed that, in terms of morphology, enzyme profile, transport systems and hormonal responsiveness, they were > 95% proxi mal tubular. The transport systems obeyed Michaelis- Menten kinetics, with the kinetic parameters of the glu cose transport system (K_m= 2.5mM, V_max = 7.7 nmol min^-1 mg^-1 protein) suggesting a higher proportion of PT cells originating from the S₁-S₂ segment of the nephron. Isolated HPTC also maintained levels of reduced glu tathione (GSH) (11.9 ± 3.2 nmol mg^-1 protein) and exhib ited cytochrome P450-dependent activity, levels of spectrally determined P450 being 0.22 ± 0.07 nmol mg^-1 protein.

3 These results demonstrate the isolation of a viable and functioning homogeneous preparation of HPTC from cortical tissue, with potential for use in short term phar macological, physiological and toxicological studies.