Scientists at Cincinnati Children’s Hospital Medical Center have developed a new method for growing large-scale human gastrointestinal tissue in the laboratory, one that spontaneously generates its own functional nervous system without requiring the complex, multi-step assembly processes that have long slowed progress in the field. Published in Nature Biomedical Engineering, the work represents a key step toward transplantable gut tissue for patients with intestinal failure and related conditions.
The approach, called the confined culture system (CCS), uses a 3D printed scaffolding tray to guide the fusion and growth of thousands of stem cell-derived spheroids into elongated intestinal, colonic, or gastric structures.
Rather than growing organoids one by one, the standard method, which typically produces tissue roughly one millimeter across after four weeks, the CCS loads approximately 4,000 spheroids into defined lanes, prompting them to merge into a unified structure within days. After ten weeks of transplantation into immunocompromised rats, the resulting tissues reached widths of up to eight centimeters, roughly ten times larger than those produced by conventional protocols.
A Nervous System That Builds Itself
CCS tissues developed an enteric nervous system, the network of neurons governing gut motility, fluid regulation, and other digestive functions, without externally added neural cells. Previous methods required separately differentiated neural crest cells to be combined with intestinal spheroids, a process known as an assembloid approach.
In CCS tissues, both excitatory and inhibitory neuron subtypes emerged spontaneously, confirmed through protein expression analysis, single-cell RNA sequencing, and electrophysiological testing.
Organ bath assays showed that the CCS tissues produced rhythmic contractile activity comparable to adult human intestinal samples, and responded robustly to nerve stimulation, responses that were significantly reduced when neuronal activity was blocked with tetrodotoxin, confirming the ENS was driving the contractions.
Earlier assembloid tissues showed minimal response to the same stimulation, suggesting that the CCS approach produces a more functionally mature nervous system than methods that assemble ENS components separately.
From Bench to Body: Integration With Host Tissue
To test whether CCS tissues could function within a living system, the team adapted a surgical procedure called a “tie in,” anastomosing the transplanted organoid directly to the host animal’s bowel. This exposed the engineered tissue to real luminal contents, bacteria, nutrients, and digestive material, for the first time.
The tissues survived the transition, maintained barrier integrity, and showed measurable adaptation: mucin production shifted, paracellular permeability improved, and spontaneous contractile amplitude increased compared to controls. Neuronal structures also continued developing between ten and twenty-two weeks post-transplantation, with ENS components migrating into the submucosal layer in a pattern that mirrors normal human gut development during adolescence.
Limitations and Open Questions
Despite the results, several important gaps remain. The mechanism by which the ENS emerges spontaneously within the CCS is not yet understood. The authors note that while the nervous system has traditionally been attributed to migrating neural crest cells, recent evidence points to additional origins, and where the neurons in CCS tissue come from remains an open research question.
The “tie in” surgical model also carried substantial challenges, including post-operative mortality that limited long-term data collection, though outcomes improved considerably when the procedure was adapted for rats using the larger CCS tissue.
Additionally, all transplantation experiments were conducted in immunocompromised animals, meaning the tissues have not yet been tested in an immune-competent environment, a critical step before any clinical application could be considered. The path from a promising laboratory model to a viable therapy for human intestinal failure remains long, but the CCS methodology provides a more accessible and scalable foundation to build from.
Organoid Transplantation: A Field Pushing Toward the Clinic, One Barrier at a Time
For patients with intestinal failure treatment options remain limited to long-term parenteral nutrition or whole intestine transplantation, both of which carry significant risks and limitations. Organoid-based therapies have long been proposed as a potential alternative. However, the gap between that promise and clinical reality has largely come down to scale, maturation, and functional complexity, precisely the problems the Cincinnati Children’s team set out to address.
The broader field has been converging on similar challenges from different angles. Researchers at UC San Francisco and the Chan Zuckerberg Biohub developed a new culture material that blends alginate microparticles into standard organoid gel, creating a substance firm enough to hold printed cells in place while gradually yielding as organoids expand, allowing stem cells to be 3D printed into defined shapes before maturation, with more consistent results.
At the funding level, the scale of ambition has grown considerably: ARPA-H selected multiple university teams to develop patient-specific bioprinted organs, including efforts at the Wyss Institute to engineer universal, clinical-scale liver tissue from adult stem cells, and at UC San Diego to produce scalable, patient-specific bioprinted livers designed to eliminate the need for donor organs or immunosuppressants.
The CCS method addresses size, speed, and functional complexity in a single protocol, advancing the field meaningfully toward clinical testing for intestinal failure.
Titled “Large-scale and innervated functional human gut tissues for transplantation via transient spheroid confinement,” the study was conducted by Holly M. Poling, Théo Noël, Akaljot Singh, Garrett W. Fisher, Konrad Thorner, Praneet Chaturvedi, Kalpana Nattamai, Kalpana Srivastava, Matthew R. Batie, Taylor Hausfeld, Amy L. Pitstick, Nicole E. Brown, Séverine Ménoret, Ignacio Anegon, Riccardo Barrile, Christopher N. Mayhew, Takanori Takebe, James M. Wells, Michael A. Helmrath and Maxime M. Mahe.
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Featured image shows employing a confinement strategy for the in vitro growth of small intestinal organoids. Image via Holly M. Poling, et al., Nature Biomedical Engineering.
