title: Label-Free Imaging of Umbilical Cord Tissue Morphology and Explant-Derived Cells.
abstract: In situdetection of MSCs remains difficult and warrants additional methods to aid with their characterizationin vivo. Two-photon confocal laser scanning microscopy (TPM) and second harmonic generation (SHG) could fill this gap. Both techniques enable the detection of cells and extracellular structures, based on intrinsic properties of the specific tissue and intracellular molecules under optical irradiation. TPM imaging and SHG imaging have been used for label-free monitoring of stem cells differentiation, assessment of their behavior in biocompatible scaffolds, and even cell trackingin vivo. In this study, we show that TPM and SHG can accurately depict the umbilical cord architecture and visualize individual cells bothin situand during culture initiation, without the use of exogenously applied labels. In combination with nuclear DNA staining, we observed a variance in fluorescent intensity in the vessel walls. In addition, antibody staining showed differences in Oct4,αSMA, vimentin, and ALDH1A1 expressionin situ, indicating functional differences among the umbilical cord cell populations. In future research, marker-free imaging can be of great added value to the current antigen-based staining methods for describing tissue structures and for the identification of progenitor cells in their tissue of origin.
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Raf
authors.identifier: 0000-0001-7694-2713
authors.initials: R
authors.lastname: Donders
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Kathleen
authors.identifier: 0000-0001-8592-6424
authors.initials: K
authors.lastname: Sanen
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Rik
authors.initials: R
authors.lastname: Paesen
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Eli
authors.identifier: 0000-0002-6757-1372
authors.initials: E
authors.lastname: Slenders
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium; Ziekenhuis Oost-Limburg, Campus St. Jan, Schiepse Bos 6, 3600 Genk, Belgium.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Gyselaers
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Stinissen
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Marcel
authors.identifier: 0000-0002-0888-2488
authors.initials: M
authors.lastname: Ameloot
authors.affiliation: Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors.forename: Niels
authors.identifier: 0000-0003-2308-406X
authors.initials: N
authors.lastname: Hellings