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Direct oxygenation and perfusion enhance viability and function of hepatocyte‐seeded scaffolds

Progress in hepatic tissue engineering has been hindered by the challenge of adequately oxygenating high density hepatocyte cultures in 3‐D scaffolds. This effort evaluated the effects of direct scaffold oxygenation and variable perfusion rates on hepatocyte morphology, viability and function in densely seeded scaffolds. The fluid shear environment was assessed using computational fluid dynamics (CFD) modeling with pore and cell aggregate parameters taken from actual seeded scaffolds. Integral silicone tubing was used to facilitate gas exchange in chitosan scaffolds seeded with 80 million rat hepatocytes. Perfusion cultures and CFD simulations were run at flow rates of 0, 5, 10 and 15 ml/min. Cultures were evaluated at day seven. Increasing flow rates improved initial rates of albumin and urea secretion, and histological analysis showed increased cell aggregation and viability with higher flow rates. However at higher flows, synthesis rates declined more rapidly over the 7 days of culture. Viable hepatocyte aggregates were localized in areas of higher oxygen levels, notably in the vicinity of the integral oxygenation tubing. The results of this study indicate that direct oxygenation and higher perfusion rates facilitate hepatic function, but higher flows also pose a substantial risk of cellular damage due to fluid shear. Supported by Wayne State University.