The Kidney
Abstract: This chapter puts forward a series of experiments in which scientists bioprinted one of the critical components of a kidney’s nephron (the filtering unit of the kidney), namely the proximal convoluted tubule where the majority of nutrient absorption back into the bloodstream takes place (and where most drug-induced toxicities of the kidney occur). The same team of researchers bioprinted colocalized (printed very close together) proximal tubules and blood vessels and, with the use of fluorescence microscopy, were able to observe vectorial transport, the process in which valuable nutrients such as serum albumin are selectively reabsorbed into the bloodstream. They also induced a state of hyperglycemia and administered a countermeasure drug, thus demonstrating the ability of their bioprinted kidney tissue to functionally respond as native kidney tissue does to an overdose of glucose and to a drug designed to mitigate this undesirable condition.