Mechanical dissociation of swine liver to produce organoid units for tissue engineering and in vitro disease modeling.

The complex intricate architecture of the liver is crucial to hepatic function. Standard protocols used for enzymatic digestion to isolate hepatocytes destroy tissue structure and result in significant loss of synthetic, metabolic, and detoxification processes. We describe a process using mechanical dissociation to generate hepatic organoids with preserved intrinsic tissue architecture from swine liver. Oxygen-supplemented perfusion culture better preserved organoid viability, morphology, serum protein synthesis, and urea production, compared with standard and oxygen-supplemented static culture. Hepatic organoids offer an alternative source for hepatic assist devices, engineered liver, disease modeling, and xenobiotic testing.

Engineered vascularized bone grafts.

Clinical protocols utilize bone marrow to seed synthetic and decellularized allogeneic bone grafts for enhancement of scaffold remodeling and fusion. Marrow-derived cytokines induce host neovascularization at the graft surface, but hypoxic conditions cause cell death at the core. Addition of cellular components that generate an extensive primitive plexus-like vascular network that would perfuse the entire scaffold upon anastomosis could potentially yield significantly higher-quality grafts. We used a mouse model to develop a two-stage protocol for generating vascularized bone grafts using mesenchymal stem cells (hMSCs) from human bone marrow and umbilical cord-derived endothelial cells. The endothelial cells formed tube-like structures and subsequently networks throughout the bone scaffold 4-7 days after implantation. hMSCs were essential for stable vasculature both in vitro and in vivo; however, contrary to expectations, vasculature derived from hMSCs briefly cultured in medium designed to maintain a proliferative, nondifferentiated state was more extensive and stable than that with hMSCs with a TGF-beta-induced smooth muscle cell phenotype. Anastomosis occurred by day 11, with most hMSCs associating closely with the network. Although initially immature and highly permeable, at 4 weeks the network was mature. Initiation of scaffold mineralization had also occurred by this period. Some human-derived vessels were still present at 5 months, but the majority of the graft vasculature had been functionally remodeled with host cells. In conclusion, clinically relevant progenitor sources for pericytes and endothelial cells can serve to generate highly functional microvascular networks for tissue engineered bone grafts.

Willingness to pay for new Papanicolaou test technologies.

The amount of money a woman is willing to pay for liquid-based cytology technology has not been measured. In the present study, 175 women answered a questionnaire asking how much they would pay to decrease their risk of dying of cervical cancer if a new (liquid-based) Papanicolaou (Pap) test was used in place of the conventional smear. When women assumed that the new Pap test reduced the risk of dying of cervical cancer from 1 in 37,000 to 1 in 50,000, the mean amount they were willing to pay was $237. If women had more than 2 children, they were willing to pay more for the new Pap test than women with 2 or fewer children. These data indicate that liquid-based and conventional Pap tests are undervalued and that cost-effectiveness studies generally have not taken into account the preference of women for new Pap test technologies.