More than 10,000 Americans are on a waitlist for liver transplants, but donor organs are scarce, and many patients are too ill for surgery. MIT engineers have developed a groundbreaking alternative: injectable "mini livers" designed to take over the functions of a failing liver.
Injectable "mini livers" designed to take over the functions of a failing liver offer a promising alternative to traditional transplants.
These innovative mini livers are comprised of hepatocytes (the main functional cells of the liver) embedded within hydrogel microspheres. This ingenious method facilitates direct injection into the body, thereby eliminating the need for invasive surgical implantation.
Engineering the Niche
The researchers' strategy centers on creating an engineered niche designed to enhance cell survival and facilitate ongoing monitoring. The hydrogel microspheres, ingeniously formulated to act as a liquid when tightly packed for injection, regain their solid structure once inside the body. This crucial property helps the hepatocytes remain localized and effectively form connections with surrounding blood vessels.
The injected mixture is further fortified with fibroblast cells, which play a vital role in supporting hepatocyte survival and promoting the crucial growth of new blood vessels into the tissue graft.
Testing and Results
In comprehensive mouse studies, the team utilized ultrasound guidance to precisely inject the cell mixture into fatty tissue (specifically, perigonadal adipose tissue) in the belly. Once localized, the injected cells successfully formed a stable, compact structure.
Significantly, new blood vessels grew into the graft area over time, effectively providing essential nutrients to the hepatocytes and enabling them to function. The injected cells demonstrated remarkable viability, remaining active for at least two months – the entire duration of the study. Crucially, they also secreted specialized proteins into the host's bloodstream, performing functions akin to a healthy liver.
Future Implications
This groundbreaking technology holds the potential to become a long-term treatment for liver disease, offering a much-needed alternative to surgical transplantation or serving as a temporary bridge until a donor organ becomes available. Future research is focused on developing methods to evade the immune system or deliver highly localized immunosuppressants, potentially eliminating the need for systemic immunosuppressive drugs.
Further, similar grafts could be successfully delivered to various other body sites, such as the spleen or near the kidneys, provided these locations offer sufficient space and adequate blood vessel access. This pioneering research was published in the journal Cell Biomaterials and received crucial funding from organizations including the National Cancer Institute and the National Institutes of Health.