Visualisation of newly synthesised collagen in vitro and in vivo.

Identifying collagen produced de novo by cells in a background of purified collagenous biomaterials poses a major problem in for example the evaluation of tissue-engineered constructs and cell biological studies to tumor dissemination. We have developed a universal strategy to detect and localize newly deposited collagen based on its inherent association with dermatan sulfate. The method is applicable irrespective of host species and collagen source.

High density gene expression microarrays and gene ontology analysis for identifying processes in implanted tissue engineering constructs.

The in vivo performance of tissue-engineered constructs is often based on generally accepted read-out parameters, like (immuno)histology. In this study, high-density gene expression microarrays and gene ontology (GO) analysis were used as a read-out tool to identify the biological processes occurring after implantation of an acellular collagen-based skin construct using a rat full-thickness wound model. A freely-available program (DAVID) was used to identify up/downregulated biological processes (GO-terms) and results were compared to wound healing/regeneration without a construct. The entire process from RNA isolation to biological interpretation is explained step-by-step. Conventional (immuno)histology was used to validate the biological processes identified and indicate that microarray analysis may provide a valuable, fast and unbiased tool to evaluate the in vivo performance of tissue-engineered constructs. However, challenges remain e.g. with regards to the development of specific GO-terms and annotation of the (rat) genome.