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Biomedical subjects

Paul P C Poyck

Publications and source records attributed to Paul P C Poyck.

4 recordsLinked to original sources
PubMed2006

Three-dimensional numerical modeling and computational fluid dynamics simulations to analyze and improve oxygen availability in the AMC bioartificial liver.

A numerical model to investigate fluid flow and oxygen (O(2)) transport and consumption in the AMC-Bioartificial Liver (AMC-BAL) was developed and applied to two representative micro models of the AMC-BAL with two different gas capillary patterns, each combined with two proposed hepatocyte distributions. Parameter studies were performed on each configuration to gain insight in fluid flow, shear stress distribution and oxygen availability in the AMC-BAL. We assessed the function of the internal oxygenator, the effect of changes in hepatocyte oxygen consumption parameters in time and the effect of the change from an experimental to a clinical setting. In addition, different methodologies were studied to improve cellular oxygen availability, i.e. external oxygenation of culture medium, culture medium flow rate, culture gas oxygen content (pO(2)) and the number of oxygenation capillaries. Standard operating conditions did not adequately provide all hepatocytes in the AMC-BAL with sufficient oxygen to maintain O(2) consumption at minimally 90% of maximal uptake rate. Cellular oxygen availability was optimized by increasing the number of gas capillaries and pO(2) of the oxygenation gas by a factor two. Pressure drop over the AMC-BAL and maximal shear stresses were low and not considered to be harmful. This information can be used to increase cellular efficiency and may ultimately lead to a more productive AMC-BAL.

Cell Culture Techniques↗
PubMed2006

Bioartificial liver: its pros and cons.

Both the large variety of liver functions for maintaining body homeostasis and the proven effectivity of whole liver transplantation in the therapy of acute liver failure (ALF), are important reasons to presume that cell-free liver support systems will not be able to adequately support the failing liver. Accordingly, bioartificial liver (BAL) systems have shown their efficacy in experimental ALF models in small and large animals, and have shown to be suitable and safe in phase 1 studies in humans with ALF. However, the optimal BAL system is still under development. Important issues are the source of the cellular component and the configuration of the BAL system with regard to cell attachment, mass transfer characteristics and oxygenation at site. The deficiency of all BAL systems to excrete bile effectively is another important topic for improvement. The great challenge for the future is to develop a well-functioning and safe human hepatic cell line which can replace the widely used porcine (xenogeneic) hepatocytes. Theoretically, a combination of a cell-free liver support system and a BAL system might be optimal for the treatment of ALF patients in the near future.

Animals↗
PubMed2005

Mild hypothermic preservation for transport purposes of the AMC bioartificial liver charged with porcine hepatocytes.

BACKGROUND: Preservation conditions play a crucial role during transport of a bioartificial liver (BAL) from the laboratory to the hospital. We assessed the possibility to preserve the AMC-BAL loaded with freshly isolated porcine hepatocytes at mild hypothermic temperatures. METHODS: Two laboratory-scale AMC-bioreactors were loaded with 1 billion freshly isolated porcine hepatocytes per experiment (n=6). Bioreactors in the control group were kept for three days at 37 degrees C. Bioreactors in the transport group were kept at 37 degrees C during day 1, at 15 degrees C during day 2, and again at 37 degrees C during day 3. In addition, long-term mild hypothermic preservation periods of 45 and 110 hr at 15 degrees C and 26 degrees C, respectively, were assessed. The effect of mild hypothermic preservation on hepatocytes inside the bioreactors was tested by determination of cell damage parameters, as well as metabolic and hepatocyte-specific functions. RESULTS: A 24-hour period of mild hypothermic preservation did not reduce any hepatocyte-specific function. LDH release was significantly higher only at day 2. Albumin production at day 2 and lidocaine elimination at day 3 were significantly higher with glucose consumption and lactate production being significantly lower at both test days. Long-term mild hypothermic preservation had a drastic negative effect on cellular viability and hepatocyte-specific function. CONCLUSIONS: Mild hypothermic preservation at temperatures as low as 15 degrees C and for a duration of 24 hr is a feasible method to preserve BAL systems loaded with freshly isolated porcine liver cells and will simplify the logistics of BAL transport from the laboratory to the hospital.

Albumins↗