title: Respiration rate in human primary renal proximal and early distal tubular cells in vitro: considerations for biohybrid renal devices.
abstract: BACKGROUND
  For biotechnological use of cells in tissue engineered applications, such as biohybrid renal devices, optimal culture conditions are required. Oxygen delivery is one of the most important cell determined system criterion for ex vivo applications. It is involved in the maintenance of highly oxygen-dependent renal tubular epithelial cells, affecting metabolic state, differentiation, and desired transport functions. The purpose of this study was to examine respiratory patterns such as basal oxygen consumption, solute transport-related oxygen demand, and oxygen concentration-dependent oxygen uptake of renal tubular epithelial cells in vitro.
  
  
  METHODS
  Respiratory patterns of highly purified human primary renal proximal (hPTC) and early distal tubular cells (hTALDC) were analyzed by perfusion respirometry. Spontaneous oxygen consumptions and maximum respirations after carbonyl cyanide m-chlorophenyl hydrazone (CCCP) uncoupling were measured. Respiration fractions contributing to basolateral Na(+) /K(+) -ATPase transport activities were assessed via ouabain inhibition and Na(+) -free medium. Furthermore, we determined oxygen uptake in dependency of oxygen concentration and morphology in various culture conditions (shaken, static).
  
  
  RESULTS
  Respiration of solely hPTC strongly depended on oxygen concentration in a Michaelis-Menten pattern at noncritical oxygen concentrations. Respiration of both cell types was significantly increased by CCCP, whereas average Na(+) /K(+) -ATPase-based oxygen uptake fractions differ significantly between the two cell types. Nevertheless, no significant differences were found in spontaneous respiration between hPTC and hTALDC.
  
  
  CONCLUSIONS
  Our results clearly indicate that cell-specific oxygen consumption parameters have to be considered in the design of biotechnological devices intended to support kidney function by cell-supported renal replacement therapy.
authors.affiliation: Kinematic Cell Research Group, Dept. of Cell Biology and Neuroscience, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Luttropp
authors.forename: Marcus
authors.initials: M
authors.lastname: Schade
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Baer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bereiter-Hahn
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D007686:Kidney Tubules, Distal / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D007688:Kidneys, Artificial; D008855:Microscopy, Electron, Scanning; D010101:Oxygen Consumption; D023822:Tissue Engineering