From "non-essential" to life-saver: the spleen’s hidden role as a built-in bioreactor

Groundbreaking Discovery

What if the human body contained a natural bioreactor capable of regenerating vital organs? A collaborative team from ​Wenzhou Medical University, Nanjing University, and University of Macau has redefined the spleen’s potential, transforming it into a ​self-sustaining hub for organ regeneration, as published in Science Translational Medicine (May 21). This breakthrough could revolutionize treatments for type 1 diabetes and beyond.

Redesigning the Spleen: From Filter to "Living Bioreactor"

Confronting the dual challenges of poor islet survival and immune rejection in traditional transplants, researchers posed a bold question: Could we repurpose an underutilized organ to nurture new life?

Led by ​Prof. Lei Dong and Prof. Jian Xiao, the team engineered ​smart nanoparticles to reprogram the spleen’s microenvironment. "We’re essentially converting the spleen into a high-performance bioreactor," Dong explains. "By enhancing extracellular matrix support, accelerating blood vessel growth, and suppressing immune attacks, we’ve created an ideal niche for transplanted cells to thrive."

In a landmark achievement, ​human islet tissues successfully matured within the reprogrammed spleens of cynomolgus macaques, demonstrating compatibility with both human and animal-derived cells. This dual success paves the way for addressing organ shortages through cross-species solutions.

Why the Spleen? Three Biological Superpowers

Ample Space: A porous structure capable of hosting billions of cells

​Nutrient-Rich Network: Direct blood supply to the liver’s portal vein mimics natural organ development

Low-Risk Adaptation: Remodeling occurs without disrupting critical bodily functions

Proven Track Record: Regenerating Organs Within the Body

The team’s spleen-based regeneration platform has achieved multiple milestones:

Functional Liver (Science Advances, 2020): Reprogrammed mouse spleens to perform liver functions

​In Situ Regeneration (Gut, 2022): Grew liver tissues using gene editing, bypassing cell transplants

​Thyroid Restoration (Advanced Science, 2024): Rebuilt hormone-producing tissues in animal models

Future Vision: A Personalized Organ Nursery

Next goal? ​Growing patient-specific organs from induced pluripotent stem cells (iPSCs). "The spleen acts like a living bioreactor embedded in our bodies," Dong describes. "With minimally invasive B-ultrasound-guided delivery, we could one day cultivate custom-made organs on demand."

While clinical applications require rigorous safety validation, this discovery challenges conventional wisdom. Once deemed "non-essential," the spleen now emerges as nature’s ultimate toolkit for regenerative medicine—proving that life’s most powerful solutions may have been inside us all along.