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Poster Session 3 — Drug Metabolism

The UK Human Tissue Bank receives donations of human liver from surgical resections and non transplantable livers from cadaveric multi organ donors (MOD) with the approval of NHS Multi Centre and Local Research Ethics Committees. These tissues can be used for the isolation of the functional cells (hepatocytes), which are subsequently used for drug metabolism, toxicity studies, bioartificial liver and cell transplantation research. A multi-variant analysis of the influence of patient and operative factors, nature of tissue and the method of tissue processing is ongoing. The effect of these factors on the quality of human hepatocytes is being evaluated. The results to date reveal optimal donors and conditions for hepatocyte isolation, which will guide the usage of each donation. Information being recorded to facilitate this ongoing analysis includes patient age, sex, BMI, blood group, smoking and alcohol history, routine pre-operative bloods and pathology. Operative factors of interest include nature of resection, Pringle time and cold ischaemic time. Isolation factors being recorded include size of specimen, time for overall isolation, collagenase digestion time, method utilised including nature of buffers and cannulation type. Results recorded include cell yield, viability (assessed by Trypan blue exclusion) and functional activity. Differences in the nature of the donation in terms of source of tissue; surgical or whole organ, and the distance from theatre to processing laboratory. From October 2001 to date, data has been collected from donations received from 63 patients undergoing liver resection and 5 whole livers. Mean viability (+ s.d.) of 83 + 7% has been obtained from these specimens with a mean yield of 5.4 million hepatocytes/g of tissue. Multivariant analysis revealed that, hepatocyte yield (cells/g of tissue) was reduced by decreasing body mass index (P= 0.025), and visual assessment of the success of tissue digestion (good (1.9 + 0.8 cells/g) or moderate (1.22 + 0.8 cells/g) gave a good indicator of increased yield (P= 0.004). Hepatocyte viability was also improved with decreasing patient age (P= 0.034), increased liver steatosis (88.0+ 6.5% vs 81.91+ 8.7) (P= 0.035) and the nature of the cannulation method employed where a venflon (86.88 + 7.6%) secured by suturing was superior to an animal catheter (79.89 + 8.63%) secured with medical adhesive (P= 0.002). Viability from surgically resected liver is approaching significance in superiority over hepatocytes isolated from MOD P= 0.09. No significant patient or isolation factors predicted cellular function on culturing. Our work to date reveals, given the precious nature of human tissue, that all donations should be considered for the isolation of human hepatocytes for research. Human liver donations can also be used for the extraction of subcellular fractions, preparation of precision cut organ slices which can be utilised in pharmacotoxicological research.