Kidney Week

Abstract: TH-OR032

Modeling the Renal Epithelial-Microvascular Niche with Perfusable, Pericyte-Lined Capillary Networks In Vitro

Session Information

• Bioengineering
  November 07, 2019 | Location: 146 A/B, Walter E. Washington Convention Center
  Abstract Time: 04:42 PM - 04:54 PM

Category: Bioengineering

• 300 Bioengineering

Authors

• Beamish, Jeffrey A., University of Michigan, Ann Arbor, Michigan, United States

Jeffrey A. Beamish, MD, PhD



Dr. Beamish is a clinical nephrologist and lecturer at the University of Michigan. He completed his undergraduate degree in chemical engineering at Northwestern University and his PhD in biomedical engineering and MD at Case Western Reserve University. His research interests include biomaterials engineering and renal epithelial regeneration.

• Cleveland, David S., University of Michigan, Ann Arbor, Michigan, United States

David S. Cleveland,

• Nimmagadda, Likitha, University of Michigan, Ann Arbor, Michigan, United States

Likitha Nimmagadda,

• Putnam, Andrew J., University of Michigan, Ann Arbor, Michigan, United States

Andrew J. Putnam,

Background

Failed renal epithelial recovery after acute kidney injury is linked to decreased capillary density and expansion of pericyte-derived fibroblasts. How this altered microvascular niche contributes to epithelial regeneration is incompletely understood. Here we report an in vitro model to study how the microvascular niche alters the regeneration of renal epithelial cells.

Methods

Microvascular networks were generated from the self-assembly of human endothelial cells and fibroblasts under established vasculogenic culture conditions. Preformed, non-perfused networks were then co-cultured with renal proximal tubular epithelial cells using Transwell inserts. Next, a culture device was developed to study effects from microvascular perfusion. The device housed multiple polydimethylsiloxane culture chambers to increase experimental throughput. Each chamber contained a perfusable microvascular network formed between gravity-fed 300 µm channels just below a porous membrane. Epithelial cells were seeded on the membrane after network formation. Microvascular network function was assessed by perfusion of 70 kDa fluorescent dextran and immunostaining. Markers of renal epithelial phenotype were measured using real time RT-PCR and immunostaining.

Results

Networks of interconnected, lumenized endothelium developed in all models. Fibroblasts occupied the interstitial space and adopted a pericyte-like morphology around vessels. Co-culture of renal epithelial cells with non-perfused microvascular networks did not affect epithelial morphology or polarity but suppressed expression of SLC22A6, AQP1 and GGT1. In our custom culture device, microvascular networks had a vessel diameter of 18.6±1.7 µm and a density of 6.4±2.0 cm/cm², spanned 0.33 cm², were perfusable in 76% of chambers seeded, and could form within ~10 µm of the epithelia. Epithelial cells seeded adjacent to the perfused capillary networks formed polarized monolayers.

Conclusion

Co-culture with non-perfused microvascular networks reduced expression of proximal tubular epithelial differentiation markers. A model with perfusable microvasculature containing capillary-scale, pericyte-lined vessels in co-culture with epithelial cells in a high-throughput culture platform was developed to better mimic the epithelial-microvascular niche in vivo.

Funding

• NIDDK Support