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Three insights regarding regeneration

Learn what regeneration is, why scientists at the Stowers Institute study it, and discover the incredible regenerative capacity of research organisms in our latest installment of our #BioBasics series!

04 June 2024

Regeneration, the remarkable ability of organisms to rebuild missing tissues and organs following injury, is a feat largely lacking in humans. While we are unable to regenerate vital organs like the heart, spinal cord, or retina, or regrow lost limbs, some animals possess an astonishing capacity for restoration. At the Stowers Institute, researchers seek to unravel the regenerative abilities of these exceptional organisms, in the hope that such knowledge may, at one point in the future, yield solutions to repair damaged human organs and body parts.

Regeneration throughout nature

Stowers scientists are actively investigating numerous research organisms with remarkable regenerative capacities. Zebrafish can regenerate sensory hair cells—groups of cells, which closely resemble hair cells in the human ear, that help them detect water motion—killifish can regenerate tail fins, and both zebrafish and killifish can rebuild heart tissue following injury.

Apple snails regenerate many body parts, and can even regrow their eyes, which are anatomically similar to human eyes with a lens, cornea, and retina. Scientists at the Institute are studying this naturally occurring regenerative ability with the hope to one day help humans suffering from eye injuries and damage like macular degeneration.

Perhaps the most impressive regenerative species studied at the Institute is the planarian flatworm—where a missing head is replaced in an average of two weeks. The mechanisms governing how these adult organisms regenerate tissues, organs, and even heads may one day provide answers for activating—or reactivating—regenerative capacity in humans.

Wound repair versus regeneration

Wound healing and tissue repair are intricate processes orchestrated by a highly coordinated cellular response. Following an injury, a complex cascade of events unfolds, involving various types of cells that receive and respond to signals instructing them to migrate to the affected site. As adults, our bodies attempt to heal and repair wounds, sometimes resulting in the formation of scars or scar tissue—a mass of cells that no longer function, marking the endpoint of the repair process.

However, in some species of adult animals, healing a wound is just the beginning of a journey. After responding to the wound, animals capable of regeneration build on this damage control reaction to activate a series of signals that lead to rebuilding the damaged tissues, and in some cases, the entirety of the missing body parts. Cells begin anew, receiving signals like the ones that directed our own early embryonic development, and allowed us to build tissues and organs. The question remains whether those cues have been lost or simply remain dormant in adults.

Researching regeneration for human health

Many animals have regenerative capabilities, even humans. And while we cannot replace a lost limb, humans do have certain abilities. One notable example of human regeneration is the production of blood cells. Stem cells residing in the bone marrow have the remarkable ability to generate millions of new red blood cells and other blood components rapidly. This continuous replenishment process allows us to maintain a healthy blood supply and recover from blood loss or injuries.

Studying the details and understanding regeneration in animals could hold clues for the future of healing, from injury to disease to potentially eliminating the need for organ transplantation. Understanding how cells perform regeneration and which signals are involved may yield hope for enabling this in humans.

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