Collecting duct cell culture

The exact mechanism(s) responsible for fluoride s nephrotoxicity remain to be defined. The fluoride ion interferes with normal cell function on several levels. Fluoride is an inhibitor of several cellular enzyme systems and dirninishes tissue respiration and anaerobic glycolysis [89]. In the kidney, fluoride interferes with transport of sodium in the proximal convoluted tubule. It also inhibits adenylate cyclase in the collecting system and dirninishes the action of antidiuretic hormone. Experimental evidence in rats indicates that the chloride dependent pump, in the thick ascending part of Henle s loop, also is inhibited [90]. In human collecting duct cell cultures, exposure to fluoride ions inhib-... 

Prepurified cultures can be considered a golden standard for the in vitro characteristics and/or for the in vitro behavior of defined cell-types. Thus, antigen characteristics, transport processes and hormone profiles of proximal tubule, distal tubule and collecting duct cells have been characterized by Wilson et al. [87] (microdissection), Baer et al. [103] (MACS) and Van Der Biest et al. [107] (FACS) (Table 2). 

Aigner J, Kloth S, Kubitza M, Kashgarian M, Dermietzel R, Minuth WW. Maturation of renal collecting duct cells in vivo and under perfusion culture. Epithelial Cell Biol 1994 3 70-78. 

Minuth WW, Gilbert P. The expression of specific proteins in cultured renal collecting duct cells. Histochemistry 1988 88 435-441. 

White S, Reeve H. Primary culture of collecting duct cell epithelium from neonate rabbit kidney in monolayer. Exp Physiol 1992 77 129-139. 

At present there is still a lack of well characterized and well differentiated cell lines of human origin representative of the different cell-types present in the nephron and the collecting duct system. However, once available, human immortahzed cell tines of defined nephron segment origin will likely provide a welcome alternative to primary cultures for studying cell properties in vitro in a cell-type dependent way. 

Tacrolimus may induce tubular dysfunction characterized as an increased excretion of urinary enzymes, decreased urinary concentrating ability, increased fractional excretion of magnesium in the presence of hypomagnesemia, hyperkalemia, hyperuricemia and fubular acidosis [12,260,645,647,705,736,737. In vitro sfudies showed fhat TAC inhibit Na/K - ATPase in rat microdissected cortical collecting duct and medullary thick ascending limb [738], and that high TAC doses added to primary human proximal tubules cultures decreased cell proliferation after 72 hours of incubation... 

Growth substrate characteristics influence epithelial cell orientation and phenotypic expression due to the interaction of receptor sites on the cell surface with specific sites in the substrate/matrix. For example, growth of the Xenopus laevis kidney cell hne A6 on microporous substrates could induce the expression of vasopressin receptors absent in solid support grown monolayers [157]. Similar observations have been reported when rabbit primary cultures of renal cortical collecting ducts were maintained on microporous supports under constant medium perfusion [158]. 

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