Traumatic brain injury (TBI) is a devastating event for which current therapies are limited. Stem cell transplantation may lead to recovery of function via different mechanisms, such as cell... Show moreTraumatic brain injury (TBI) is a devastating event for which current therapies are limited. Stem cell transplantation may lead to recovery of function via different mechanisms, such as cell replacement through differentiation, stimulation of angiogenesis and support to the microenvironment. Adult hair follicle bulge-derived stem cells (HFBSCs) possess neuronal differentiation capacity, are easy to harvest and are relatively immune-privileged, which makes them potential candidates for autologous stem cell-based therapy. In this study, we apply in vivo multimodal, optical and magnetic resonance imaging techniques to investigate the behavior of mouse HFBSCs in a mouse model of TBI. HFBSCs expressed Luc2 and copGFP and were examined for their differentiation capacity in vitro. Subsequently, transduced HFBSCs, preloaded with ferumoxytol, were transplanted next to the TBI lesion (cortical region) in nude mice, 2 days after injury. Brains were fixed for immunohistochemistry 58 days after transplantation. Luc2- and copGFP-expressing, ferumoxytol-loaded HFBSCs showed adequate neuronal differentiation potential in vitro. Bioluminescence of the lesioned brain revealed survival of HFBSCs and magnetic resonance imaging identified their localization in the area of transplantation. Immunohistochemistry showed that transplanted cells stained for nestin and neurofilament protein (NF-Pan). Cells also expressed laminin and fibronectin but extracellular matrix masses were not detected. After 58 days, ferumoxytol could be detected in HFBSCs in brain tissue sections. These results show that HFBSCs are able to survive after brain transplantation and suggest that cells may undergo differentiation towards a neuronal cell lineage, which supports their potential use for cell-based therapy for TBI. Show less
Vogel, S.; Schafer, C.; Hess, S.; Folz-Donahue, K.; Nelles, M.; Minassian, A.; ... ; Aswendt, M. 2019
The aim of this thesis was to investigate the feasibility of multimodal visualization techniques to observe adult stem cells, in particular HFBSCs, in the living animal. Due to the novelty of... Show moreThe aim of this thesis was to investigate the feasibility of multimodal visualization techniques to observe adult stem cells, in particular HFBSCs, in the living animal. Due to the novelty of HFBSCs in the field of inner ear research, a series of proof-of-principle experiments have been undertaken to investigate if these cells can undergo neuronal differentiation, tolerate genetic modification with lentiviral constructs containing the genes coding for reporter proteins, and tolerate subsequent loading with nanoparticles in vitro. In addition, it was of importance to examine if HFBSCs do integrate into modiolar tissue and if they can be visualized in the cochlea of the guinea pig. Lastly, we performed in vivo studies to investigate the ototoxic effect of ouabain in guinea pigs and the behavior of HFBSCs in mice with traumatic brain injury. Show less
The aim of the work included in this PhD thesis was to explore the diverse application possibility of using NIR fluorescent probes with specific properties to visualize and characterize cancer and... Show moreThe aim of the work included in this PhD thesis was to explore the diverse application possibility of using NIR fluorescent probes with specific properties to visualize and characterize cancer and cell death. In this thesis, we mainly focus on optical imaging and its application, both at microscopic and macroscopic level. Because we believe optical imaging in particular represents a technology that has unique potential to exploit further our knowledge in preclinical research. First, we imaged breast tumors and their metastases using combinations of four NIR fluorescent probes that possess different optical imaging properties. Then, we studied two different NIR fluorescent probes, PSVue and a heat shock protein-90 alkylator (NIR fluorescent conjugate of GSAO), which can be used to non-invasively imaging cell death with different optical modules in a mouse model of traumatic brain injury. Next, we employed the NIR fluorescently tagged GSAO as a biomarker for monitoring breast cancer cell death after chemotherapy. Moreover, we provides a general discussion about the advantages and the challenging that the state-of-art optical imaging is facing and shares some future prospective. This thesis ends with a summary that outlined the major findings of studies described in different chapters and explored the clinical implications. Show less
The aim of this work was to develop methods to measure structural changes in the skeleton using MicroCT. In addition, these new methods should be able to quantify biologically relevant changes. In... Show moreThe aim of this work was to develop methods to measure structural changes in the skeleton using MicroCT. In addition, these new methods should be able to quantify biologically relevant changes. In order to do this, normalized methods to analyse MicroCT scans and perform quantitative measurements within these datasets are described in this thesis. These techniques were combined with a biological angiogenesis assay and used as research tools in a study comparing various different combination treatments of bone metastases. Show less
Stem cell therapy has raised enthusiasm as a potential treatment for cardiovascular diseases. However, questions remain about the in vivo behavior of the cells after transplantation and the... Show moreStem cell therapy has raised enthusiasm as a potential treatment for cardiovascular diseases. However, questions remain about the in vivo behavior of the cells after transplantation and the mechanism of action with which the cells could potentially alleviate disease symptoms. The objective of the research as described in this thesis was to visualize survival, proliferation, and migration of embryonic (ESC) and adult stem cells using non-invasive molecular imaging techniques in small animal models of cardiovascular diseases. The major findings can be described as follows: (1) Non-invasive bioluminescence imaging is a validated tool to monitor donor cell survival, proliferation, migration, and misbehavior; (2) ESC are a potential source for true regenerative therapy; (3) ESC form teratomas; (4) Adult stem cell survival is short-lived, but of all cells currently used in the clinic, mononuclear cells show the most prolonged survival; (5) Transplantation of mononuclear cells can preserve cardiac function in the short term after myocardial infarction in mice; (6) Compared to other measurements of murine cardiac function, Micro-CT is a superior method to assess cardiac geometry and function; and (7) Transplantation of mononuclear cells in peripheral artery disease is hampered by dismal cell survival and homing. These findings illustrate the current challenges for optimizing stem cell therapy for cardiovascular disease. Show less
