Cells on spheres help sick livers.

Cells on spheres help sick livers

Although it is still several years down the road, medical researchers are progressing toward an easier, safer and less expensive alternative to lier transplantation for some patients.

When the liver stops performing, as in severe acute liver failure, the prognosis is grim. The liver performs many vital functions, among them carbohydrate and fatr metabolism, dettoxification of poisons and manufacture of blood proteins. Presently the only treatment is transplantation, which islimited by organ availability, pateint suitability and technical complexity. Although 602 transplants were performed last year in the United States 4,000 to 6,000 patients could have used a substitute liver, according to teh Department of Health and Human Services.

Since it is liver function and not necessarily the actual liver that many of these patients must have in oder to live, liver cells could in principle be sufficient. To test this idea in practice, researchers from the Albert Einstein College of Medicine in the Bronx attached liver cells from healthy rats onto protein-coated microscopic spheres and injected them into four groups of mutant rats with specific inborn liber disorders. The carbohydrate spheres were coated with collagen -- a major component of connective tissue -- since this provides a lifelike matrix for the attached cells.

The researchers, led by Achilles A. Demetrious, now at Vanderbilt University Medical Center in Nashville, observed that that the cell-laden microcarriers injected into the rats' abdominal cavities attached primarily to fatty tissue on the rats' pancreases and , and , from there, took over the liver functions the rats lacked.

One rate group studied was treated with cyclosporine to suppress its immunological machinery, which otherwise would have "perceived" the injected liver cells as foreign. Cell rejection was not a problem with another mutant group studied because those rats were genetically almost identical to the donor rats. In both of these groups, liver function increased throughout the 28-day-long experiment. In contrast, liver function returned only briefly to the remaining two groups of rats, which were neither genetically similar to the donor rats nor immunosuppressed with cyclosporine. After six days, these rats' liver deficiencies gradually increases until they wrere as severe as before the cell injection. The researchers report their results in the October PROCEEDINGS OF THE NATIONAK ACADEMY OF SCIENCES (Vol. 83, No. 19).

Clinical trials in which humans with liver disorders are treated with microcarrier-attached cells are several years off, Demetriou says. He adds that he anticipates no fundamental barries that might prevent the treatment from becoming a useful therapy for many, though not all, pateitns with liver disease.

Paul Russell, chief of transplantation at Massachusetts General Hospital in Boston, says he consider this selective transplantation of cells "a very reasonable possibility" for some patients who need whole-organ transplants. However, he adds, transplantation will remain the treatment of choice in cases where the liver is so diseased that it needs to be totally replaced.