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Biomaterial Mobilizes Host Stem Cells to Promote Kidney Regeneration

Review of “In Situ Tissue Regeneration of Renal Tissue Induced by Collagen Hydrogel Injection” from STEM CELLS Translational Medicine by Stuart P. Atkinson

The regenerative force of stem cells alongside the supporting role of biomaterials has proven to be a highly synergistic combination when it comes to tissue regeneration [1, 2]. However, a new study from the laboratory of James J. Yoo (Wake Forest School of Medicine, North Carolina, USA) now suggests that regeneration may not require exogenous stem cells, and biomaterial alone may suffice to repair damage to the kidney [3]! 

Lee et al. hypothesized that for a complex organ such as the kidney, the creation of a conducive environment would attract healthy stem cells from the surrounding tissue to regenerate said damaged area. To investigate this hypothesis, the authors injected a collagen hydrogel into the kidneys of mice with ischemia/reperfusion damage and assessed the consequences at four weeks. Excitingly, tests indicated that host renal stem/progenitor cells (PAX-2, CD24, and CD133 positive) and mesenchymal stem cells (CD44 positive) mobilized and migrated into the biomaterial within the damaged zone. Overall, stem cell invasion of the biomaterial helped to regenerate kidney structures such as glomeruli (synaptopodin and CD31 positive) and tubules (cytokeratin and neprilysin positive) and promote recovery of function.

Biomaterial injection appears to be a simple and effective means mobilize stem cells and regenerate the kidney, although the authors suggest that the incorporation of substrate-mediated signaling into the biomaterial could further enhance the process [4, 5]. Furthermore, the authors hope that further studies into the mechanisms of stem cell mobilization/migration and stem cell differentiation into glomerular and tubular cells could aid the development of this promising therapy.

For more on this simple and effective approach to promote kidney regeneration, stay tuned to the Stem Cells Portal!

Discussion Points

  • Can this regenerative technique work in other tissues?
  • How can we further modify the biomaterial to enhance regeneration?
  • What mechanisms control cell mobilization/migration and differentiation?


  1. Atala A, Organ preservation, organ and cell transplantation, tissue engineering, and regenerative medicine: the terms may change, but the goals remain the same. Tissue Eng Part A 2014;20:445-6.
  2. Atala A, Recent developments in tissue engineering and regenerative medicine. Curr Opin Pediatr 2006;18:167-71.
  3. Lee SJ, Wang H-J, Kim T-H, et al., In Situ Tissue Regeneration of Renal Tissue Induced by Collagen Hydrogel Injection. STEM CELLS Translational Medicine 2018;7:241-250.
  4. Ju YM, Atala A, Yoo JJ, et al., In situ regeneration of skeletal muscle tissue through host cell recruitment. Acta Biomaterialia 2014;10:4332-4339.
  5. Ko IK, Ju YM, Chen T, et al., Combined systemic and local delivery of stem cell inducing/recruiting factors for in situ tissue regeneration. The FASEB Journal 2012;26:158-168.