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Abstract: TH-OR132

Mechanistic Analysis of Flow-Enhanced Vascularization in Kidney Organoids

Session Information

Category: Development, Stem Cells, and Regenerative Medicine

  • 501 Development, Stem Cells, and Regenerative Medicine: Basic

Authors

  • Homan, Kimberly, Harvard University, Cambridge, Massachusetts, United States
  • Gupta, Navin R., Brigham & Women''s Hospital/Massachusetts General Hospital, Brighton, Massachusetts, United States
  • Kroll, Katharina T., Harvard University, Cambridge, Massachusetts, United States
  • Kolesky, David B., Harvard University, Cambridge, Massachusetts, United States
  • Skylar-Scott, Mark A., Harvard University, Cambridge, Massachusetts, United States
  • Miyoshi, Tomoya, Brigham and Women's Hospital , Boston, Massachusetts, United States
  • Mau, Donald, Wyss Institute, Boston, Massachusetts, United States
  • Valerius, M. Todd, Brigham and Women's Hospital , Boston, Massachusetts, United States
  • Ferrante, Thomas, Wyss Institute, Boston, Massachusetts, United States
  • Bonventre, Joseph V., Brigham and Women's Hospital , Boston, Massachusetts, United States
  • Lewis, Jennifer A., Harvard School of Engineering and Applied Sciences, Cambridge, Massachusetts, United States
  • Morizane, Ryuji, Brigham and Women's Hospital , Boston, Massachusetts, United States
Background

Multilineage cellular communication is implicated in organ development and cellular maturation. We have recently shown that fluidic shear stress (FSS) promotes the vascularization and maturation of kidney organoids derived from human pluripotent stem cells (hPSCs) in vitro. The addition of VEGF is deemed to facilitate vascular formation during kidney organoid development in vivo, however, mechanisms of organoid vascularization and maturation under FSS conditions in vitro have yet to be identified.

Methods

Early kidney organoids (pretubular aggregate stage) derived from hPSCs were subjected to FSS in printed millifluidic chips. During 10 days of perfusion at a FSS of 0.04 dynes/cm2, they were given organoid media without growth factors or with either added VEGF (1, 10, 100 ng/mL) or Avastin (250 mg/mL, which inhibits VEGF). The degree, distribution, and maturation of CD146+and CD31+vascular networks were evaluated by immunostaining, RT-qPCR, and image analysis (ImageJ Angiotool plugin). Tubulo-vascular proximity was quantified by distance transformation and surface area contact calculations using Imaris software.

Results

FSS-induced vascularized organoids exhibit upregulated VEGF expression, compared to static controls. Interestingly, total vascular abundance was independent of VEGF signaling under high FSS; however, manipulation of the VEGF pathway reduced vascular invasion to glomeruli and tubulo-vascular surface area contact. Reducing the nephron epithelial communication with vasculature led to an increase in vascular branching and a reduction in average vessel length.

Conclusion

In developing kidney organoids under FSS, modifying the native VEGF intrinsic gradient results in random templating of the same amount of vasculature with less tubular and glomerular integration. Our results indicate that maintenance of intrinsic growth factor production may be critical to develop functional bioengineered kidneys from hPSCs in vitro, which may supplant current renal replacement therapies in the future.

Funding

  • NIDDK Support