The liver is the most common site for colorectal cancer (CRC) metastasis and there is an urgent need for new tissue culture models to study colorectal cancer liver metastasis (CRLM) as current models do not mimic the biological, biochemical, and structural characteristics of the metastatic microenvironment. Decellularization provides a novel approach for the study of the cancer extracellular matrix (ECM) as decellularized scaffolds retain tissue-specific features and biological properties. In the present study, we created a 3D model of CRC and matched CRLM using patient-derived decellularized ECM scaffolds seeded with the HT-29 CRC cell line. Here, we show an increased HT-29 cell proliferation and migration capability when cultured in cancer-derived scaffolds compared to same-patient healthy colon and liver tissues. HT-29 cells cultured in CRLM scaffolds also displayed an indication of epithelial-mesenchymal transition (EMT), with a loss of E-cadherin and increased Vimentin expression. EMT was confirmed by gene expression profiling, with the most represented biological processes in CRLM-seeded scaffolds involving demethylation, deacetylation, a cellular response to stress metabolic processes, and a response to the oxygen level and starvation. HT-29 cells cultured in cancer-specific 3D microenvironments showed a reduced response to treatment with 5-fluorouracil and 5-fluorouracil combined with Irinotecan when used at a standard IC50 (as determined in the 2D culture). Our 3D culture system with patient-derived tissue-specific decellularized ECM better recapitulates the metastatic microenvironment compared to conventional 2D culture conditions and represents a relevant approach for the study of CRLM progression and assessing the response to chemotherapy agents.

In the field of in vitro liver disease models, decellularised organ scaffolds maintain the original biomechanical and biological properties of the extracellular matrix and are established supports for in vitro cell culture. However, tissue engineering approaches based on whole organ decellularized scaffolds are hampered by the scarcity of appropriate bioreactors that provide controlled 3D culture conditions. Novel specific bioreactors are needed to support long-term culture of bioengineered constructs allowing non-invasive longitudinal monitoring. Here, we designed and validated a specific bioreactor for long-term 3D culture of whole liver constructs. Whole liver scaffolds were generated by perfusion decellularisation of rat livers. Scaffolds were seeded with Luc+HepG2 and primary human hepatocytes and cultured in static or dynamic conditions using the custom-made bioreactor. The bioreactor included a syringe pump, for continuous unidirectional flow, and a circuit built to allow non-invasive monitoring of culture parameters and media sampling. The bioreactor allowed non-invasive analysis of cell viability, distribution, and function of Luc+HepG2-bioengineered livers cultured for up to 11 days. Constructs cultured in dynamic conditions in the bioreactor showed significantly higher cell viability, measured with bioluminescence, distribution, and functionality (determined by albumin production and expression of CYP enzymes) in comparison to static culture conditions. Finally, our bioreactor supports primary human hepatocyte viability and function for up to 30 days, when seeded in the whole liver scaffolds. Overall, our novel bioreactor is capable of supporting cell survival and metabolism and is suitable for liver tissue engineering for the development of 3D liver disease models.

Introduction Digitisation and increasing workload presents an opportunity for artificial intelligence (AI) tools in histopathology. In the UK, approximately 580,000 people live infected with hepatitis B or C and an estimated 30,000 liver biopsies are performed annually in the US. We performed a literature review and analysis to determine understanding of interobserver variation in viral hepatitis grading and staging as a foundation for developing a novel AI tool. Methods A literature search for papers examining viral hepatitis, interobserver variation and Ishak/Knodell scoring returned 24 papers. Abstracts were reviewed independently with inclusion and exclusion criteria by two consultants and a registrar, and consensus discussion determined the inclusion of eight papers in the final analysis. Average Cohen's kappa coefficient scores of interobserver variation for necro-inflammatory activity (NIA) and fibrosis were gathered and these were used to give a range, mean and weighted mean kappa scores. Results Results are summarised in the table 1 below. There is poor interobserver variation amongst pathologists, particularly for grading (NIA) of viral hepatitis with mean kappa score 0.33 and weighted kappa score 0.30. Kappa scores for fibrosis showed moderate to substantial agreement (mean kappa score was 0.66 and weighted mean kappa score 0.63. Additional papers noted success with image analysis to improve observer agreement for fibrosis. Discussion To our knowledge, this is the first review examining interobserver variation of the Knodell and Ishak systems. The results demonstrate where AI can be used to improve agreement between pathologists and therefore provide more consistent pathological assessment for patients.