Injectable Mini Livers Offer Hope for Patients Awaiting Transplant

The resulting treatment gap drives waitlist mortality and prolonged critical care. To help address this challenge, engineers have created injectable “satellite livers” designed to augment hepatic function without removing the native organ. Researchers now report preclinical results supporting this minimally invasive approach as a potential alternative or bridge to transplant.

Developed at the Massachusetts Institute of Technology (Cambridge, MA, USA), the approach uses hydrogel microspheres co-delivered with primary hepatocytes and supportive fibroblasts. The microspheres are engineered to behave like a liquid when closely packed, enabling delivery through a syringe, and then to regain a solid structure in vivo. This creates an engineered niche that keeps cells localized, promotes early contact with host blood vessels, and supports long-term graft stability. The strategy aims to provide hepatocyte function without surgical implantation.

The team established an ultrasound-guided injection technique and used ultrasound imaging to monitor graft stability over time. In the study, the cell-microsphere mixture was injected into belly fat, specifically perigonadal adipose tissue. The researchers note that comparable grafts could be placed at other sites such as the spleen or near the kidneys, provided adequate space and vascular access. This placement flexibility is intended to simplify delivery and follow-up imaging.

In mouse experiments, the injected cells formed a compact, stable structure that became vascularized, with new blood vessels growing adjacent to the hepatocytes. The grafts remained viable for eight weeks, the full duration of the study, and secreted specialized liver proteins into the host circulation. These findings indicate sustained hepatocyte activity after a single injection and support evaluation of the platform as a long-term functional support for liver disease.

The study appears in Cell Biomaterials and involved investigators from MIT’s Koch Institute for Integrative Cancer Research and the Institute for Medical Engineering and Science. The researchers report that recipients would likely require immunosuppressive drugs, and they are exploring “stealthy” hepatocytes or local delivery of immunosuppressants from the microspheres to reduce systemic exposure.

“We think of these as satellite livers. If we could deliver these cells into the body, while leaving the sick organ in place, that would provide booster function,” said Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT, and a member of MIT’s Koch Institute for Integrative Cancer Research and the Institute for Medical Engineering and Science (IMES).

“The way we see this technology is it can provide an alternative to surgery, but it can also serve as a bridge to transplantation where these grafts can provide support until a donor organ becomes available. And if we think they might need another therapy or more grafts, the barriers to do that are much less with this injectable technology than undergoing another surgery,” said Vardhman Kumar, MIT postdoctoral researcher.

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