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2014
Journal Article
Titel
Spectroscopic profiling of mesenchymal stem cells and their progeny
Titel Supplements
Abstract
Abstract
Introduction: Mesenchymal stem cells (MSCs) are multipotent progenitor cells that have been identified and isolated from numerous tissues within the body. They are defined by the potential to differentiate into adipocytes, chondrocytes and osteoblasts. Due to this plasticity, MSCs are of high interest for tissue engineering and regenerative medicine applications. However, these aspirations were hampered by analytical pitfalls. MSCs and their progeny represent a donor-dependent heterogeneous cell population, which cannot be purified by the expression of single marker proteins1. To overcome these challenges we utilized Raman spectroscopy, a non-invasive optical tool, for the marker-independent molecular profiling of MSCs. Raman spectroscopy detects inelastic light scattering of molecular vibrations within living cells. A Raman spectrum represents a biochemical fingerprint of individual cells. We hypothesized that Raman spectral profiles help to resolve the heterogeneous character of MSC populations and could give further information about the status and fate decision of single cells. Materials and methods: Human MSCs were isolated from bone marrow, adipose tissue and placenta. Isolated cells were expanded and characterized by three-lineage differentiation. In addition Raman spectra of each cell isolate were collected. A custom-built Raman system was used to acquire spectra of single cells. Cellular spectra were background- corrected and cut into the wavenumber range 400-1800 cm_1. The absolute spectral intensities were vector-normalized. Processed spectra were analyzed using Principal component analysis (PCA). PCA reduces the spectral variables and computes score values, which describe each single spectrum. In addition PCA resolves the variances within the overall dataset. Results: All Raman spectra of the different MSCs types showed specific signals of nucleic acids, carbohydrates, lipids and proteins, which summarized to individual complex profiles. Based on these profiles spectral signals were identified, which differed significantly in MSCs of different tissue sources. Cell differentiation into the three-lineages was further indicated by specific spectral changes. Particularly, osteogenic differentiation was clearly detectable by an incremental increase of the hydroxyapatite signal at 961 cm_1. Raman spectra of MSCs and their progeny showed donor specificity. Discussion and conclusions: Raman spectral profiling of MSCs is a non-invasive method to identify similarities and differences between cell populations. This method could be used to directly compare the biochemical profiles of cells, which were isolated from different donors or tissues. In the future, Raman spectroscopy could be applied as a prescreening tool for the patient's cells. In addition, spectral profiles can indicate ongoing differentiation processes in vitro. Acknowledgments: This study was financially supported by a Fraunhofer-Gesellschaft internal program (Attract 692263 to KSL). Disclosures: Authors have nothing to disclose.