Kidney Week

Abstract: PO0493

Recreating Renal Function in a Human Glomerulus and Proximal Tubule Microphysiological System

Session Information

• Bioengineering: Organoids and Organs-on-a-Chip
  November 04, 2021 | Location: On-Demand, Virtual Only
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bioengineering

• 300 Bioengineering

Authors

• Zhang, Stephanie Y., Binghamton University Thomas J Watson School of Engineering and Applied Science, Binghamton, New York, United States

Stephanie Y. Zhang, MS

• Mahler, Gretchen, Binghamton University Thomas J Watson School of Engineering and Applied Science, Binghamton, New York, United States

Gretchen Mahler,

Background

Preclinical tests for pharmaceutical discovery extensively rely on static, 2D cultures and animal models. While these methods are commonly used, they poorly represent human responses due to the lack of architecture and physiological stimuli (2D culture), and human cells (animal models). Kidney microphysiological systems (MPS) better support renal function with controlled, 3D fluidic platforms, and serve as valuable tools in determining renal toxicity to new drugs. Current kidney MPS model individual regions of the nephron (glomerulus and proximal tubule or PCT) but fail to incorporate multiple filtration and reabsorption interfaces. Our study established a 7 day tri-culture of podocytes, endothelial, and PCT epithelial cells in a glomerulus and PCT MPS with key functional features.

Methods

The MPS consisted of: T-Junction, glomerulus housing (GH), and PCT chip. Media from the bloodstream flowed into the T-Junction, splitting 10% of flow to GH. The GH had a polyethersulferone membrane with human endothelial cells (HUVECs) and podocytes (CIHP-1) seeded at 10⁵ cells/cm² on opposing sides. Connected to GH, PCT polycarbonate chip housed 10⁵ cells/cm² of human PCT cells (HK-2) and outputs primary filtrate. At shear stress of 0.7-1.5 dyne/cm², velocity flow was measured based on daily filtrate output. Glomerular filtration was tested by challenging the system with 0.1 mg/mL of FITC-human serum albumin (FITC-HSA). PCT reabsorption was tested using fluorescent glucose analog (2-NBDG). Cultures were starved for 2 hrs, and later treated with media containing 200 mg/mL of 2-NBDG for 2 hrs. After 7 days of exposure, cell membranes were stained and imaged for F-actin, VE-cadherin, ZO-1, and nephrin.

Results

At a total pump flowrate of 45.3 µL/min, 17.7 µL/min (± 5.08 µL/min) exited as filtrate and 27.6 µL/min (± 7.63 µL/min) recirculated in the bloodstream. In the MPS, average daily filtrate output was 0.016 mL/min, filtration of FITC-HSA in the MPS was over 90%, and glucose output in the filtrate supported PCT reabsorption. Confocal images displayed cell type-specific protein expression.

Conclusion

Filtering of HSA, glucose reabsorption, and marker expression in the MPS indicates a physiological representation of renal filtration and reuptake in a human glomerulus and PCT. Our glomerulus and PCT MPS is a relevant preclinical tool for testing drug candidates for kidney toxicity.