Assessing the influence of the decellularization process on the tissue microstructure by using 3D contrast-enhanced X-ray microfocus computed tomography

Details

Supervisors

Kerckhofs, Greet

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

This thesis aimed to assess the potential of CECT imaging to evaluate the effect of tissue decellularization protocols on the 3D microstructure of human tissues. We analyzed the fascia lata tissue mainly composed of dense collagen fibers and containing few cells. Three tissue samples were decellularized by the standard proprietary protocol of the tissue bank not using soap (P5). Three tissue samples were decellularized by a similar protocol but with soap (P1). They were compared to three native tissue samples. We first optimized the acquisition of the images. Our results show that the CECT scan is a very promising technology that will help to study fibrous structures. We first analyzed the scans on 2D projected views of the 3D scans to determine the thickness of the fibers as well as the inter-fiber spacing. We did not detect any significant difference between the three groups of samples (native, P5, P1), supporting that the decellularization process had no impact on the microstructure. We then performed an automatic extraction of the fibers from the 3D scans using Avizo’sXFiber modules. We did not detect any significant difference between the three groups of samples (native, P5, P1). Interestingly, we observed good concordance between the 2D and 3D analyses. The samples were thereafter stained to perform conventional 2D histology. We could show the absence of nuclei in the decellularized samples and similar qualitative appearance of the collagen fibers. Based on our analyses, we did not detect any significant impact of the decellularization methods on the 3D microstructure of the fascia lata samples. These results are very encouraging. CECT could bring an added value in the evaluation of decellularized tissues. Indeed, the most commonly used methods include qualitative 2D conventional histology and electron microscopy, quantitative measurement of molecular components such as DNA, collagen, proteins, . . . but direct 3D microstructure analysis is missing. In conclusion, this work highlights the possibilities of analysis that can be performed using CECT as well as the advantages and limitations of the scanning techniques and the processing of the images. The complementarity of scans and conventional 2D histology is highlighted. Future perspectives would be to test more samples, to test other decellularization protocols as well as to develop this technique for other types of tissues.