Injectable “Satellite Livers” Offer Hope for Liver Failure Patients

More than 10,000 Americans are currently on the waiting list for a liver transplant, but the demand for donor organs far exceeds the supply.¹ many individuals with liver failure are deemed too ill to undergo the surgery itself. Now, a groundbreaking development from MIT engineers offers a potential alternative: “mini livers” that can be injected into the body to take over the functions of a failing liver.^{1, 2}

Restoring Liver Function Through Injectable Technology

The human liver performs approximately 500 essential functions, including blood clotting regulation, bacterial removal from the bloodstream, and drug metabolism.³ These vital processes are primarily carried out by cells called hepatocytes. For years, researchers have sought ways to restore hepatocyte function without resorting to traditional liver transplantation.³

The MIT team, led by Sangeeta Bhatia, developed a novel approach called Injected, Self-assembled, Image-guided Tissue Ensembles (INSITE). This involves injecting a mixture of hepatocytes and hydrogel microspheres. The microspheres act as a scaffold, allowing the cells to remain localized and integrate with the host’s circulatory system.² This engineered niche enhances cell survival and enables noninvasive monitoring of the graft’s health.²

How the “Satellite Livers” Work

The hydrogel microspheres are designed to behave like a liquid during injection, allowing them to flow through a syringe. Once inside the body, they regain their solid structure, creating a spongy scaffold.¹ Blood vessels then grow into this scaffold, providing the transplanted cells with the necessary nutrients and enabling them to perform their functions.^{1, 2} The injected mixture as well includes fibroblast cells, which support hepatocyte survival and promote blood vessel growth.²

Researchers utilized ultrasound guidance for precise injection and monitoring of the implant’s stability.² In initial tests conducted in mice, the “mini livers” were injected into fatty tissue in the abdomen. However, the team suggests that similar grafts could potentially be delivered to other locations, such as the spleen or near the kidneys, as long as sufficient space and blood vessel access are available.²

Promising Results in Preclinical Trials

In studies involving mice, the injected cells remained viable and functional for at least eight weeks, producing essential liver enzymes and proteins.^{1, 2} This suggests the potential for long-term treatment of liver disease.² “We think of these as satellite livers,” says Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT. “If we could deliver these cells into the body, while leaving the sick organ in place, that would provide booster function.”¹

A Bridge to Transplantation and Beyond

The researchers envision this technology as a potential alternative to surgery, as well as a bridge to transplantation for patients awaiting donor organs.² The injectable approach offers a less invasive option and could allow for repeated treatments or grafts more easily than traditional surgery.²

While patients may initially require immunosuppressive drugs to prevent rejection, the research team is exploring strategies to develop “stealthy” hepatocytes that evade the immune system or to deliver immunosuppressants locally via the hydrogel microspheres.²

Future Directions

This research represents a significant step forward in the treatment of liver disease. While still in its early stages, the development of injectable “satellite livers” offers a promising new hope for patients who are not eligible for traditional liver transplantation.¹

Sources:

1. MIT News: Injectable “satellite livers” could offer alternative to liver transplantation
2. The Register: MIT researchers test injectable ‘satellite liver’ in mice
3. ScienceBlog: Injectable Backup Livers Could Help Thousands Too Sick for Transplant Surgery