A bioartificial renal proximal tubule is successfully engineered as a first step towards a bioartificial kidney for improved renal substitution therapy. To engineer the tubule, a tunable hollow fiber membrane with an exterior skin layer that provides immunoprotection for the cells from extracapillary blood flow and a coarse inner surface that facilitates a hydrogel coating for cell attachment was embedded in a “lab-on-a-chip” model for the small-scale exploratory testing under flow conditions. Fibrin was coated onto the inner surface of the hollow fiber, and human renal proximal tubule epithelial cells were then seeded. Using this model, we successfully cultured a confluent monolayer, as ascertained by immunofluorescence staining for ZO-1 tight junctions and other proximal tubule markers, scanning electron microscopy, and FITC-inulin recovery studies. Furthermore, the inulin studies, combined with the creatinine and glucose transport profiles, suggested that the confluent monolayer exhibits functional transport capabilities. The novel approaches here may eventually improve current renal substitution technology for renal failure patients. 1. Introduction Hemodialysis has been widely used to treat patients suffering from end-stage renal failure. With hemodialysis, millions of renal failure patients in the world have not only survived, but are also able to successfully perform certain levels of social activities and functions. However, hemodialysis is still inefficient as a renal replacement therapy. It only provides intermittent blood filtration and is unable to replicate the important absorptive, metabolic, endocrine, and immunological functions of the natural kidney. To overcome such limitations, Aebischer et al. first proposed the concept of a bioartificial kidney that incorporates living epithelial cells of the kidney proximal tubule for the selective transport of water and solutes across the cell-attached membranes [1, 2]. Humes et al. have developed a bioartificial renal tubule assist device (RAD) using commercial hemodialysis hollow fiber membranes based on this concept [3–6] and conducted clinical trials on 10 to 40 patients with acute renal failure; encouraging results were reported [7, 8]. Saito et al. also developed a bioartificial renal tubule device (BRTD) with a capacity of treating 10？L of ultrafiltrate per day. Using proximal tubular epithelial cells in conjunction with continuous hemofiltration, the BRTD offers a potential wearable, continuous renal replacement therapy for patients with chronic renal failure [9–14]. In the development of
References
[1]
P. Aebischer, T. K. Ip, G. Panol, and P. M. Galletti, “The bioartificial kidney: progress towards an ultrafiltration device with renal epithelial cells processing,” Life Support Systems, vol. 5, no. 2, pp. 159–168, 1987.
[2]
T. K. Ip and P. Aebischer, “Renal epithelial-cell-controlled solute transport across permeable membranes as the foundation for a bioartificial kidney,” Artificial Organs, vol. 13, no. 1, pp. 58–65, 1989.
[3]
H. D. Humes, D. A. Buffington, S. M. MacKay, A. J. Funke, and W. F. Weitzel, “Replacement of renal function in uremic animals with a tissue- engineered kidney,” Nature Biotechnology, vol. 17, no. 5, pp. 451–455, 1999.
[4]
H. D. Humes, W. H. Fissell, W. F. Weitzel et al., “Metabolic replacement of kidney function in uremic animals with a bioartificial kidney containing human cells,” American Journal of Kidney Diseases, vol. 39, no. 5, pp. 1078–1087, 2002.
[5]
H. D. Humes, S. M. MacKay, A. J. Funke, and D. A. Buffington, “Tissue engineering of a bioartificial renal tubule assist device: in vitro transport and metabolic characteristics,” Kidney International, vol. 55, no. 6, pp. 2502–2514, 1999.
[6]
S. M. Mackay, A. J. Funke, D. A. Buffington, and H. David Humes, “Tissue engineering of a bioartificial renal tubule,” ASAIO Journal, vol. 44, no. 3, pp. 179–183, 1998.
[7]
H. D. Humes, W. F. Weitzel, R. H. Bartlett et al., “Initial clinical results of the bioartificial kidney containing human cells in ICU patients with acute renal failure,” Kidney International, vol. 66, no. 4, pp. 1578–1588, 2004.
[8]
J. Tumlin, R. Wali, W. Williams et al., “Efficacy and safety of renal tubule cell therapy for acute renal failure,” Journal of the American Society of Nephrology, vol. 19, no. 5, pp. 1034–1040, 2008.
[9]
Y. Fujita, M. Terashima, T. Kakuta et al., “Transcellular water transport and stability of expression in aquaporin 1-transfected LLC-PK1 cells in the development of a portable bioartificial renal tubule device,” Tissue Engineering, vol. 10, no. 5-6, pp. 711–722, 2004.
[10]
N. Ozgen, M. Terashima, T. Aung et al., “Evaluation of long-term transport ability of a bioartificial renal tubule device using LLC-PK1 cells,” Nephrology Dialysis Transplantation, vol. 19, no. 9, pp. 2198–2207, 2004.
[11]
A. Saito, “Research into the development of a wearable bioartificial kidney with a continuous hemofilter and a bioartificial tubule device using tubular epithelial cells,” Artificial Organs, vol. 28, no. 1, pp. 58–63, 2004.
[12]
A. Saito, T. Aung, K. Sekiguchi et al., “Present status and perspectives of bioartificial kidneys,” Journal of Artificial Organs, vol. 9, no. 3, pp. 130–135, 2006.
[13]
A. Saito, H. Suzuki, K. Bomsztyk, and S. Ahmad, “Regeneration of peritoneal effluent by Madin-Darby canine kidney cells-lined hollow fibers,” Materials Science and Engineering C, vol. 6, no. 4, pp. 221–226, 1998.
[14]
Y. Sato, M. Terashima, N. Kagiwada et al., “Evaluation of proliferation and functional differentiation of LLC-PK 1 cells on porous polymer membranes for the development of a bioartificial renal tubule device,” Tissue Engineering, vol. 11, no. 9-10, pp. 1506–1515, 2005.
[15]
R. W. Baker, Membrane Technology and Applications, John Wiley & Sons, New York, NY, USA, 2nd edition, 2004.
[16]
R. R. Seeley, T. D. Stephens, and P. Tate, Anatomy and Physiology, McGraw-Hill, Boston, Mass, USA, 7th edition, 2006.
[17]
Z. Y. Oo, R. Deng, M. Hu et al., “The performance of primary human renal cells in hollow fiber bioreactors for bioartificial kidneys,” Biomaterials, vol. 32, no. 34, pp. 8806–8815, 2011.
[18]
M. Huijuan, W. Xiaoyun, Y. Xumin, W. Hengjin, and S. Xia, “Effect of continuous bioartificial kidney therapy on porcine multiple organ dysfunction syndrome with acute renal failure,” ASAIO Journal, vol. 53, no. 3, pp. 329–334, 2007.
[19]
Food and Drug Administration CDRH BSE Working Group, Guidance for FDA Reviewers and industry Medical Devices Containing Materials Derived from Animal Sources (Except for in vitro Diagnostic Devices), 1998, http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm073810.htm.
[20]
S. Jockenhoevel, G. Zund, S. P. Hoerstrup, et al., “Fibrin gel-advantages of a new scaffold in cardiovascular tissue engineering,” in Proceedings of the 14th Annual Meeting of the European-Association-for-Cardio-Thoracic-Surgery, Frankfurt, Germany, 2000.
[21]
J. F. Mano, G. A. Silva, H. S. Azevedo et al., “Natural origin biodegradable systems in tissue engineering and regenerative medicine: present status and some moving trends,” Journal of the Royal Society Interface, vol. 4, no. 17, pp. 999–1030, 2007.
[22]
A. Mol, M. I. Van Lieshout, C. G. Dam-De Veen et al., “Fibrin as a cell carrier in cardiovascular tissue engineering applications,” Biomaterials, vol. 26, no. 16, pp. 3113–3121, 2005.
[23]
Q. Ye, G. Zünda, P. Benedikta, et al., “Fibrin gel as a three dimensional matrix in cardiovascular tissue engineering,” in Proceedings of the 13th Annual Meeting of the European-Association-for-Cardio-Thoracic-Surgery, Glasgow, Scotland, 1999.
[24]
R. Büttemeyer, J. W. Mall, M. Paulitschke, A. Rademacher, and A. W. Philipp, “In a pig model ePTHE grafts will sustain for 6 weeks a confluent endothelial cell layer formed in vitro under shear stress conditions,” European Journal of Vascular and Endovascular Surgery, vol. 26, no. 2, pp. 156–160, 2003.
[25]
T. R. Dunkern, M. Paulitschke, R. Meyer et al., “A novel perfusion system for the endothelialisation of PTFE grafts under defined flow,” European Journal of Vascular and Endovascular Surgery, vol. 18, no. 2, pp. 105–110, 1999.
[26]
M. Hu, M. Kurisawa, R. Deng et al., “Cell immobilization in gelatin-hydroxyphenylpropionic acid hydrogel fibers,” Biomaterials, vol. 30, no. 21, pp. 3523–3531, 2009.
[27]
T. K. Ip, P. Aebischer, and P. M. Galletti, “Cellular control of membrane permeability. Implications for a bioartificial renal tubule,” ASAIO Transactions, vol. 34, no. 3, pp. 351–355, 1988.
[28]
Y. Duan, N. Gotoh, Q. Yan et al., “Shear-induced reorganization of renal proximal tubule cell actin cytoskeleton and apical junctional complexes,” Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 32, pp. 11418–11423, 2008.
[29]
M. Essig, F. Terzi, M. Burtin, and G. Friedlander, “Mechanical strains induced by tubular flow affect the phenotype of proximal tubular cells,” American Journal of Physiology, vol. 281, no. 4, pp. F751–F762, 2001.
[30]
K. J. Jang and K. Y. Suh, “A multi-layer microfluidic device for efficient culture and analysis of renal tubular cells,” Lab on a Chip, vol. 10, no. 1, pp. 36–42, 2010.
[31]
H. Zhang, F. Tasnim, J. Y. Ying, and D. Zink, “The impact of extracellular matrix coatings on the performance of human renal cells applied in bioartificial kidneys,” Biomaterials, vol. 30, no. 15, pp. 2899–2911, 2009.
[32]
M. Ni, J. C. M. Teo, M. S. B. Ibrahim et al., “Characterization of membrane materials and membrane coatings for bioreactor units of bioartificial kidneys,” Biomaterials, vol. 32, no. 6, pp. 1465–1476, 2011.
[33]
J. C. M. Teo, R. R. G. Ng, C. P. Ng, and A. W. H. Lin, “Surface characteristics of acrylic modified polysulfone membranes improves renal proximal tubule cell adhesion and spreading,” Acta Biomaterialia, vol. 7, no. 5, pp. 2060–2069, 2011.
[34]
M. Wieser, G. Stadler, P. Jennings et al., “hTERT alone immortalizes epithelial cells of renal proximal tubules without changing their functional characteristics,” American Journal of Physiology, vol. 295, no. 5, pp. F1365–F1375, 2008.
[35]
P. M. T. Deen, S. Nielsen, R. J. M. Bindels, and C. H. Van Os, “Apical and basolateral expression of Aquaporin-1 in transfected MDCK and LLC-PK cells and functional evaluation of their transcellular osmotic water permeabilities,” Pflugers Archiv European Journal of Physiology, vol. 433, no. 6, pp. 780–787, 1997.
