Kidney Week

Abstract: TH-OR132

Mechanistic Analysis of Flow-Enhanced Vascularization in Kidney Organoids

Session Information

• Translational Research Innovations in Kidney Organoid and Bioengineered Model Systems
  October 25, 2018 | Location: 4, San Diego Convention Center
  Abstract Time: 04:42 PM - 04:54 PM

Category: Development, Stem Cells, and Regenerative Medicine

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

Authors

• Homan, Kimberly, Harvard University, Cambridge, Massachusetts, United States

Kimberly Homan, PhD

• Gupta, Navin R., Brigham & Women''s Hospital/Massachusetts General Hospital, Brighton, Massachusetts, United States

Navin R. Gupta,

• Kroll, Katharina T., Harvard University, Cambridge, Massachusetts, United States

Katharina T. Kroll,

• Kolesky, David B., Harvard University, Cambridge, Massachusetts, United States

David B. Kolesky,

• Skylar-Scott, Mark A., Harvard University, Cambridge, Massachusetts, United States

Mark A. Skylar-Scott,

• Miyoshi, Tomoya, Brigham and Women's Hospital , Boston, Massachusetts, United States

Tomoya Miyoshi,

• Mau, Donald, Wyss Institute, Boston, Massachusetts, United States

Donald Mau,

• Valerius, M. Todd, Brigham and Women's Hospital , Boston, Massachusetts, United States

M. Todd Valerius,

• Ferrante, Thomas, Wyss Institute, Boston, Massachusetts, United States

Thomas Ferrante,

• Bonventre, Joseph V., Brigham and Women's Hospital , Boston, Massachusetts, United States

Joseph V. Bonventre,

• Lewis, Jennifer A., Harvard School of Engineering and Applied Sciences, Cambridge, Massachusetts, United States

Jennifer A. Lewis,

• Morizane, Ryuji, Brigham and Women's Hospital , Boston, Massachusetts, United States

Ryuji Morizane,

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