201 results about "Human hepatocyte" patented technology

The present invention relates to the preparation of non-human animals having chimeric livers, whereby some or substantially all of the hepatocytes present are human hepatocytes. It is based, at least in part, on the discovery that rats, tolerized in utero against human hepatocytes, were found to serve as long-term hosts for human hepatocytes introduced post-natally, and the introduced hepatocytes maintained their differentiated phenotype, as evidenced by continued production of human albumin.

One of the major hurdles of cellular therapies for the treatment of liver failure is the low availability of functional human hepatocytes. Although embryonic stem (ES) cells represent a potential cell source for therapy, current methods for differentiation result in mixed cell populations or low yields of the cells of interest. The present invention provides for a rapid, direct differentiation method that yields a homogeneous population of endoderm-like cells with 95% purity. In one embodiment, mouse ES cells cultured on top of collagen-sandwiched hepatocytes differentiate and proliferate into a uniform and homogeneous cell population of endoderm-like cells. The endoderm-like cell population was positive for Foxa2, Sox17 and AFP, and could further differentiate into hepatocyte-like cells that demonstrate hepatic morphology, functionality, and gene and protein expression. Incorporating the hepatocyte-like cells into a bioartificial liver device to treat fulminant hepatic failure improved animal survival, thereby underscoring the therapeutic potential of these cells.

A rotating wall vessel is used as a culture vessel and bioreactor for the cultivation of hepatocytes in the form of spheroids to generate a culture with many properties of the intact liver. These properties include enzyme activity comparable to fresh cells and long-term maintenance of viability and cellular function for periods on the order of months. The cultures may be used to produce hepatocyte products, evaluate metabolism of an agent, propagate Hepatitis C virus and test agents as inhibitors of this virus. Thus, the culture system disclosed herein makes long term functional cultivation of human hepatocytes feasible.

Leptin was previously demonstrated to exert potent immune modulatory properties in several immune mediated disorders. The aim of the study was to determine leptin's anti-tumor effect in a murine model of human hepatocellular carcinoma (HCC). In vivo, Athymic T cell deficient (nude) mice transplanted with 1×106 human Hep3B cells, followed by administration of two daily intraperitoneal doses of 0.5 mg / gram leptin for 6 weeks. Leptin administration induced a significant reduction in tumor size and improved survival in nude mice. Histologically, tumors of leptin-administered mice featured increased inflammatory exudate in interphase areas. Leptin-induced tumor suppression was associated with a significant increase in peripheral natural killer (NK) cell number. Splenocytes from leptin-treated mice featured decreased expression of CIS mRNA. To determine which lymphocyte subset is a prerequisite for the anti tumor effect of leptin, T&B cell deficient (Scid) mice and T,B& NK deficient (Scid-Beige) mice were subcutaneously implanted with Hep3B tumor cells, with and without the daily intraperitoneal administration of 0.5 mg / gram leptin for 6 weeks. SCID mice featured leptin-associated tumor suppression similar to those of nude mice. In contrast, NK-deficient SCID-Beige mice developed larger tumors. To further establish natural killer cell's central role in mediation of leptin's anti-tumor effect, NK cells were incubated in vitro with increasing doses of leptin, demonstrating a dose-dependent increase in cytotoxic activity. Incubation of leptin with hepatoma cell line was found to induce a dose-dependent reduction in hepatoma cell proliferation, suggesting an additive direct anti-tumor effect. Further synergism in inhibition of hepatoma cell proliferation in vitro was achieved following addition of natural killer cells. HCC cells expressed leptin receptor mRNA, while addition of leptin induced increased mRMA expression of STAT2 and SOCS1 on tumor cell lines. Leptin administration induces a significant suppression of human HCC. This effect is mediated by induction of natural killer cell proliferation and activation, and by direct inhibition of tumor growth. Decreased natural killer cell expression of inhibitory CIS protein and over expression of the anti-proliferative STAT2 and SOCS1 proteins in HCC lines may underline both anti cancerous effects of leptin.