Abstract: FR-OR099

A Microfluidic Kidney Organoid System Reveals Real-Time Dynamics of Nutrient Absorption

Session Information

Category: Developmental Biology and Inherited Kidney Diseases

  • 402 Stem Cells

Authors

  • Gulieva, Ramila E., University of Washington, Seattle, Washington, United States
  • Himmelfarb, Jonathan, Kidney Research Institute, Seattle, Washington, United States
  • Freedman, Benjamin S., University of Washington, Seattle, Washington, United States
Background

Human mini-kidney organoids derived from pluripotent stem cells have great potential for kidney disease modeling and regeneration. Microfluidic flow is an essential component of the nephron for reabsorption and filtration, but is absent from existing organoid cultures. To more accurately model nephron functions in vivo, we tested whether introduction of fluid flow into kidney organoids could be used to visualize absorption of transport cargoes and nutrients in real time.

Methods

Human mini-kidneys were either differentiated de novo from hPSCs or transferred into chambers from cryopreserved stocks in microfluidic flow chambers. Fluorescence-labeled glucose, albumin and dextran were introduced and monitored live every 15 minutes over the course of 24 hours, under constant perfusion conditions. Absorption was quantified using image intensity analysis with background subtraction, compared to static conditions without flow, or in the presence of glucose transport inhibitors. Transporter expression was determined by immunofluorescence.

Results

Organoid proximal tubules, distal tubules, and podocytes differentiated normally, expressed SGLT2 and LRP2 transporters, and remained stable under flow for as long as two weeks. Accumulation of glucose occurred very rapidly, while absorption of albumin and dextran increased gradually in a linear fashion and eventually reached a plateau over 24 hours. The magnitude of absorption was significantly increased and featured increased signal to noise under flow conditions, compared to static conditions where absorption was minimal. Inhibition of SGLT transporters blocked glucose absorption in a dose-dependent manner.

Conclusion

The combination of kidney organoids with microfluidics enables visualization of nutrient and transport cargo absorption in nephron-like structures with high spatial and temporal resolution. Organoids under flow exhibit increased ability to absorb nutrients, relative to other cells in these cultures or organoids without flow. Our results indicate that this system can be utilized to accurately model absorption dynamics of specific substrates and to test the effects of therapeutic compounds, such as SGLT2 inhibitors. As flow is an essential component of the nephron, these experiments also build towards more sophisticated organoid microphysiological systems and artificial kidney devices.

Funding

  • NIDDK Support