Hepatic support by hepatocyte transplantation in congenitally metabolic diseased rats

Nagase analbuminemic rats (NAR), which lack albumin synthesis in the liver, underwent intrasplenic hepatocyte transplantation (HCTx), and the long-term effects were studied using functional and morphological examinations. Hepatocytes were isolated from congenic F344 rats with collagenase infusion, and 1 x 10(7) cells were injected into the spleen of 3-month-old NAR (n = 10). Serum albumin increased with time, reaching 53.9 mg/dl 14 months after HCTx, which was equivalent to 2.1% (maximum 4%) of serum albumin in normal rats. On the other hand, untreated NAR showed persistently low serum albumin levels (0.99 +/- 0.23 mg/dl at 10 months). According to immunostaining with anti-rat albumin antibody at 16 months after HCTx, hepatocyte grafts occupied 27-41% of the spleen area and weighed 120-420 mg, which was equivalent to 0.8-2.9% of a whole liver. Our study demonstrated that grafted hepatocytes can grow in the spleen with the ability to synthesize albumin. HCTx in NAR is a new experimental system to monitor the function and survival of grafted heptocytes without sacrificing the animals by measuring serum albumin levels. Certain manipulations to facilitate the growth of grafted hepatocytes are necessary to achieve sufficient hepatic support in HCTx.