Liver development is restored by blastocyst complementation of HHEX knockout in mice and pigs.

BACKGROUND: There are over 17,000 patients in the US waiting to receive liver transplants, and these numbers are increasing dramatically. Significant effort is being made to obtain functional hepatocytes and liver tissue that can for therapeutic use in patients. Blastocyst complementation is a challenging, innovative technology that could fundamentally change the future of organ transplantation. It requires the knockout (KO) of genes essential for cell or organ development in early stage host embryos followed by injection of donor pluripotent stem cells (PSCs) into host blastocysts to generate chimeric offspring in which progeny of the donor cells populate the open niche to develop functional tissues and organs. METHODS: The HHEX gene is necessary for proper liver development. We engineered loss of HHEX gene expression in early mouse and pig embryos and performed intraspecies blastocyst complementation of HHEX KO embryos with eGFP-labeled PSCs in order to rescue the loss of liver development. RESULTS: Loss of HHEX gene expression resulted in embryonic lethality at day 10.5 in mice and produced characteristics of lethality at day 18 in pigs, with absence of liver tissue in both species. Analyses of mouse and pig HHEX KO fetuses confirmed significant loss of liver-specific gene and protein expression. Intraspecies blastocyst complementation restored liver formation and liver-specific proteins in both mouse and pig. Livers in complemented chimeric fetuses in both species were comprised of eGFP-labeled donor-derived cells and survived beyond the previously observed time of HHEX KO embryonic lethality. CONCLUSIONS: This work demonstrates that loss of liver development in the HHEX KO can be rescued via blastocyst complementation in both mice and pigs. This complementation strategy is the first step towards generating interspecies chimeras for the goal of producing human liver cells, tissues, and potentially complete organs for clinical transplantation.

Complete staghorn calculi: random prospective comparison between extracorporeal shock wave lithotripsy monotherapy and combined with percutaneous nephrostolithotomy.

PURPOSE: We determined the preferred treatment of staghorn calculi. MATERIALS AND METHODS: Between January 1992 and December 1994 we performed a prospective, randomized, single center study involving 50 kidneys with complete staghorn calculi: 27 renal units were treated with extracorporeal shock wave lithotripsy (ESWL) monotherapy (group 1) and 23 were treated with combined (initial) percutaneous nephrostolithotomy with ESWL (group 2). The 2 treatment groups were compared regarding stone size, grade of collecting system dilatation and urine culture at presentation. The number of treatment sessions, narcotic doses, renal colic episodes, septic complications, unplanned ancillary procedures, length of hospitalization, total treatment duration and stone-free rate at 6 months were recorded and compared. RESULTS: At the conclusion of therapy the stone-free rate was significantly greater in group 2 than in group 1 (74 versus 22%, respectively, p = 0.0005). The complication rate was significantly greater in group 1, with 15 septic complications (fever greater than 38.5C for longer than 3 days) in 10 patients compared to only 2 episodes in group 2 (p = 0.007). The unplanned ancillary procedure rate was significantly greater in group 1 (8 procedures in 7 patients versus 1 procedure in group 2, p = 0.03). The overall treatment length was significantly shorter in group 2 (1 versus 6 months, p = 0.0006). There was no significant difference in the number of procedures performed with anesthesia or in the number of hospitalization days between the 2 treatment groups. CONCLUSIONS: Combined percutaneous nephrostolithotomy and ESWL should be recommended as the first line treatment choice for most patients with staghorn stones.