We previously proposed a quantitative approach to assess donor organs for cadaver renal transplantation. To improve on our original scoring system, we studied 34 324 patients who received cadaver re...

The culture of primary hepatocytes as spheroids creates an efficient three-dimensional tissue construct for hepatic studies in vitro . Spheroids possess structural polarity and functional bile canaliculi with normal differentiated function. Thus, hepatocyte spheroids have been proposed as the cell source in a variety of diagnostic, discovery, and therapeutic applications, such as a bioartificial liver. Using a novel rocking technique to induce spheroid formation, kinetics of spheroid formation, cell-cell adhesion, gene expression, and biochemical activities of rat hepatocyte spheroids were tested over 14 days of culture. Evidence was provided that the formation of spheroids occurred faster and with fewer nonadherent hepatocytes in rocked suspension culture compared to a traditional rotational system. Hepatocyte spheroids in rocked culture showed stable expression of more than 80% of 242 liver-related genes including those of albumin synthesis, urea cycle, phase I and II metabolic enzymes, and clotting factors. Biochemical activity of rocked spheroid hepatocytes was superior to monolayer culture of hepatocytes on tissue culture plastic and collagen. Conclusion: Spheroid formation by rocker technique was more rapid and more efficient than by rotational technique. Rocker-formed spheroids appear suitable for application in a bioartificial liver or as an in vitro liver tissue construct. (Hepatology 2009.)

We have developed a novel bioreactor based on the observation that isolated porcine hepatocytes rapidly and spontaneously aggregate into spheroids under oscillation conditions. The purpose of this study was to characterize the influence of oscillation frequency (0.125 Hz, 0.25 Hz), cell density (1-10 × 106 cells/mL), and storage condition (fresh, cryopreserved) of porcine hepatocytes on the kinetics of spheroid formation. The viability and metabolic performance of spheroid hepatocytes was also compared to monolayer culture. We observed that both fresh and cryopreserved porcine hepatocytes began formation of spheroids spontaneously at the onset of oscillation culture. Spheroid size was directly related to cell density and time in culture, though inversely related to oscillatory frequency. Spheroid formation by fresh porcine hepatocytes was associated with decreased cell death (lactate dehydrogenase release, 1.3 ± 1.0 vs. 3.1 ± 0.7 U/mL, P < 0.05) and increased metabolic performance (albumin production, 14.7 ± 3.3 vs. 4.6 ± 1.4 fg/c/h, P < 0.0001; ureagenesis from ammonia, 267 ± 63 vs. 92 ± 13 μmol/L/h, P < 0.001) compared with monolayer culture. In conclusion, based on the favorable properties of rapid spheroid formation, increased hepatocellular function, and ease of scale-up, the spheroid reservoir bioreactor warrants further investigation as a bioartificial liver for support of liver failure. (Liver Transpl 2005;11:901–910.)

Donor organ shortage is the main limitation to liver transplantation as a treatment for end‐stage liver disease and acute liver failure. Liver regenerative medicine may in the future offer an alternative form of therapy for these diseases, be it through cell transplantation, bioartificial liver (BAL) devices, or bioengineered whole organ liver transplantation. All three strategies have shown promising results in the past decade. However, before they are incorporated into widespread clinical practice, the ideal cell type for each treatment modality must be found, and an adequate amount of metabolically active, functional cells must be able to be produced. Research is ongoing in hepatocyte expansion techniques, use of xenogeneic cells, and differentiation of stem cell‐derived hepatocyte‐like cells (HLCs). HLCs are a few steps away from clinical application, but may be very useful in individualized drug development and toxicity testing, as well as disease modeling. Finally, safety concerns including tumorigenicity and xenozoonosis must also be addressed before cell transplantation, BAL devices, and bioengineered livers occupy their clinical niche. This review aims to highlight the most recent advances and provide an updated view of the current state of affairs in the field of liver regenerative medicine. Stem Cells 2017;35:42–50

Purpose: To investigate the correlation between MR elastography (MRE) assessed spleen stiffness and direct portal vein pressure gradient (D‐HVPG) measurements in a large animal model of portal hypertension.Materials and Methods: Cholestatic liver disease was established in adult canines by common bile duct ligation. A spin echo based echo planar imaging (EPI) MRE sequence was used to acquire three‐dimensional/three axis (3D/3‐axis) abdominal MRE data at baseline, 4 weeks, and 8 weeks. Liver biopsies, blood samples, and D‐HVPG measurements were obtained simultaneously.Results: Animals developed portal hypertension (D‐HVPG: 11.0 ± 5.1 mmHg) with only F1 fibrosis after 4 weeks. F3 fibrosis was confirmed after 8 weeks despite no further rise in portal hypertension (D‐HVPG: 11.3 ± 3.2 mmHg). Mean stiffnesses of the spleen increased over two‐fold from baseline (1.72 ± 0.33 kPa) to 4 weeks (3.54 ± 0.31 kPa), and stabilized at 8 weeks (3.38 ± 0.06 kPa) in a pattern consistent with changes in portal pressure. A positive correlation was observed between spleen stiffness and D‐HVPG (r²= 0.86;P< 0.01).Conclusion: These findings indicate a temporal relationship between portal hypertension and the development of liver fibrosis in a large animal model of cholestatic liver disease. The observed direct correlation between spleen stiffness and D‐HVPG suggest a noninvasive MRE approach to diagnose and screen for portal hypertension. J. Magn. Reson. Imaging 2011;.