Primary renal cells
In most cases, approaches to renal regeneration are developed
using cell-based systems. The development of reliable kidney cell
sources is a prerequisite step for these approaches. Kidney tissue
is composed of more than 20 specialized cell types that are structurally
organized into morphologically and functionally distinct
compartments. Primary renal cells can be harvested from normal
and diseased kidney tissue and grown in culture while maintaining
the phenotype and function of the kidney from which they were
derived. Proximal tubule cells (PTCs) play an important role in kidney
physiological functions [17,18]. Therefore, it is essential to isolate
functional human renal PTCs from kidney tissues. Primary PTC
cultures have many advantages and are more representative of
normal PTC physiology than immortalized cell lines; however, primary
kidney cells, including PTCs, lose their expression of essential
genes during passaging and limit their use to only 2–5 passages
[19]. The optimal combination of high purity, consistently
well-preserved growth, and differentiation is observed at passage
2–3 [20]