Engineers at MIT have designed an injectable therapy meant to give patients with failing livers a boost of extra organ function without a transplant. The approach, described in a study from MIT's Institute for Medical Engineering and Science, mixes liver cells called hepatocytes with microscopic hydrogel spheres and supportive fibroblast cells, then injects the combination under the skin or into fatty tissue, where it knits into a small, self-contained pocket of functioning liver tissue the researchers call a "satellite liver."
In mice, the injected cells remained viable for at least eight weeks — the full length of the study — and generated many of the enzymes and proteins a healthy liver produces, according to the ScienceDaily summary of the findings, published in the journal Cell Biomaterials. Vardhman Kumar, an MIT postdoc and the study's lead author, said new blood vessels grew directly alongside the transplanted hepatocytes, which he said is why the cells were able to survive as long as they did.
An alternative, not a replacement
More than 10,000 people in the United States with chronic liver disease are currently on the waiting list for a transplant, far outstripping the supply of donor organs. Existing liver-cell infusion techniques let injected hepatocytes diffuse throughout the body, which limits how much extra function they can provide and makes it hard to monitor whether the graft is working. The MIT team's hydrogel-based approach instead keeps the cells clustered in one accessible spot.
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.
Sangeeta Bhatia, MIT professor and senior author of the study
The research is still in its early, preclinical stage: the results come entirely from mice, not humans, and the study tracked outcomes for only two months, so it does not show whether the effect would hold up over years or translate to people. The current version of the technique also requires patients to take immunosuppressive drugs so their bodies don't reject the injected cells — a real burden for anyone already managing chronic illness. The MIT group says it is now working on "stealthy" hepatocytes engineered to evade immune detection, and on loading the hydrogel spheres themselves with immunosuppressant drugs so they could be released locally rather than systemically.
The work was funded in part by the National Cancer Institute, the National Institutes of Health, the Wellcome Leap HOPE Program, and the Howard Hughes Medical Institute. Should the approach eventually reach clinical trials, the researchers envision it as a bridge therapy — supporting patients while they wait for a donor organ, or in some cases functioning as a standalone treatment for people not eligible for a full transplant. That step, and the human safety testing it would require, remains years away.
