Development of an immunosuppressed orthotopic hepatocellular carcinoma rat model for the evaluation of chemo- and radioembolization therapies.

Hepatocellular carcinoma (HCC) is widely known to be chemo-resistant and presents with significant liver disease resulting in low tolerability to systemic chemotherapy. As a counter measure, more targeted therapies such as trans-arterial chemoembolization (TACE) and trans-arterial radioembolization (TARE) have been developed. To further optimize these therapies, animal models are critical in elucidating the molecular events in disease progression and test new treatment options. The present study focuses on the development of a hepatoma bearing rat model. N1S1 rat hepatoma cells were transfected by a lentiviral method and injected into the liver of Sprague Dawley (SD) and Rowett Nude (RNU) rats. Longitudinal tumor growth was observed by bioluminescence imaging (BLI) and liver/tumor histology. In both models, tumors were visible within 4 days post cell inoculation. Tumor take rates were 52 % and 73 % for male and female SD rats, respectively, and 100 % for male RNU rats. By day 12 and 15 post inoculation, we recorded complete tumor regression in male and female SD rats. Liver histology showed advanced fibrosis in the tumor regressed SD rats, whilst RNU rats exhibited the characteristic sheet pattern of Novikoff tumor with mild liver fibrosis. Increased CD3 and TUNEL staining observed in SD rat livers may be key factors for tumor regression. Our data reveal that the immunocompetent SD rats are not recommended as a model for therapeutic investigations. The immunosuppressed RNU rats, however, are characterized by consistent and reliable tumor growth and thus a desirable model for future therapeutic investigations.

Preparation of Heat-Denatured Macroaggregated Albumin for Biomedical Applications Using a Microfluidics Platform.

Albumin is widely used in pharmaceutical applications to alter the pharmacokinetic profile, improve efficacy, or decrease the toxicity of active compounds. Various drug delivery systems using albumin have been reported, including microparticles. Macroaggregated albumin (MAA) is one of the more common forms of albumin microparticles, which is predominately used for lung perfusion imaging when labeled with radionuclide technetium-99m (99mTc). These microparticles are formed by heat-denaturing albumin in a bulk solution, making it very challenging to control the size and dispersity of the preparations (coefficient of variation, CV, ∼50%). In this work, we developed an integrated microfluidics platform to create more tunable and precise MAA particles, the so-called microfluidic-MAA (M2A2). The microfluidic chips, prepared using off-stoichiometry thiol-ene chemistry, consist of a flow-focusing region followed by an extended and water-heated curing channel (85 °C). M2A2 particles with diameters between 70 and 300 µm with CVs between 10 and 20% were reliably prepared by adjusting the flow rates of the dispersed and continuous phases. To demonstrate the pharmaceutical utility of M2A2, particles were labeled with indium-111 (111In) and their distribution was assessed in healthy mice using nuclear imaging. 111In-M2A2 behaved similarly to 99mTc-MAA, with lung uptake predominately observed early on followed by clearance over time by the reticuloendothelial and renal systems. Our microfluidic chip represents an elegant and controllable method to prepare albumin microparticles for biomedical applications.