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Molecular Imaging for Stem Cell Research |
Stem cell research requires a wide range of skills in order to study the entire process of cell selection, isolation,
modification, inoculation, tracking and fate monitoring. This last step of observation of the stem cells after
injection in the animal is challenging: it requires being able
to monitor the cells:
- at the organism level to follow their migration,
- and at a more precise level to estimate cell survival, proliferation, and ideally differentiation
>> High sensitivity to track cell migration pathways
Photon Imager intensified CCD.
1 -> Lenses
2 -> Photocathode
3 -> Multichannel plate
4 -> High voltages
5 -> Phosphor screen
Photon Imager intensified CCD. 1 -> Lenses
2 -> Photocathode
3 -> Multichannel plate
4 -> High voltages
5 -> Phosphor screen
The design of the Photon Imager, with its intensified CCD, makes it really sensitive from the first second of the acquisition.
The technology relies on an intensification of the signal by a factor 106;
as a consequence, the Photon Imager belongs to the most sensitive systems on the market for detection of weak signals.
The principle is described opposite: photons, after focalization by a series of lenses (1), are converted to electrons when they reach the photocathode (2). Electrons are amplified by the microchannel plate (3), and converted back to photons by a phosphorus screen (5). The resulting light spot is recorded by the CCD camera.
With such an amplification of the signal, thermal noise can easily be isolated since its intensity level remains much lower than that of any photon amplified by the intensifier tube. This way, the CCD can record the signal and forward the related information in a very fast way, with a frame rate of 43 Hz. The excellent sensitivity and real time capabilities of the Photon Imager come directly from this design, unique for in vivo whole body optical imagers for small animals.
The principle is described opposite: photons, after focalization by a series of lenses (1), are converted to electrons when they reach the photocathode (2). Electrons are amplified by the microchannel plate (3), and converted back to photons by a phosphorus screen (5). The resulting light spot is recorded by the CCD camera.
With such an amplification of the signal, thermal noise can easily be isolated since its intensity level remains much lower than that of any photon amplified by the intensifier tube. This way, the CCD can record the signal and forward the related information in a very fast way, with a frame rate of 43 Hz. The excellent sensitivity and real time capabilities of the Photon Imager come directly from this design, unique for in vivo whole body optical imagers for small animals.
>> Linearity to correlate signal intensity with cell proliferation estimation
Users of the Photon Imager can rely on its outstandingly large dynamic range:
Stem cells or migrating cells luminescence expression can therefore be followed and compared,
with the possibility to compare cell proliferation and cell fate with time,
or between individuals when the cells are located in similar locations.
>> Versatility to offer fields of view from the whole-body scale to the organ level
Being able to detect your migrating cells by whole body imaging of your mouse, in vivo and non invasively, is great. Yet it becomes really exciting only when you can have a closer look at the cells, to localize or quantify them more precisely. The Photon Imager, with its moving stage, allows you to really focus on the fate of your cells.
Whole body imaging of mouse with GFP stem cells and control mouse.
The migration pathway of neuronal precursors
Being able to detect your migrating cells by whole body imaging of your mouse, in vivo and non invasively, is great. Yet it becomes really exciting only when you can have a closer look at the cells, to localize or quantify them more precisely. The Photon Imager, with its moving stage, allows you to really focus on the fate of your cells.
Whole body imaging of mouse with GFP stem cells and control mouse.
The migration pathway of neuronal precursors
>> Non invasive imaging to follow the migration longitudinally
If cell migration could be studied in vitro in Petri dishes, it would be so much easier. Yet animal models are necessary to have a physiological environment, with all the interactions and factors relevant to a living organism. Then if one needs to disturb this organism for the purpose of imaging, isn't it going backwards?...
The Photon Imager was designed to help you provide your animals the best physiological conditions, to minimize disturbance. The system has a heating table, the temperature of which can be adapted; and anesthesia is performed with gas or injection, for your convenience. And with the new In Actio imaging mode, you can even get rid of anesthesia, if this is compatible with your protocols!
If cell migration could be studied in vitro in Petri dishes, it would be so much easier. Yet animal models are necessary to have a physiological environment, with all the interactions and factors relevant to a living organism. Then if one needs to disturb this organism for the purpose of imaging, isn't it going backwards?...
The Photon Imager was designed to help you provide your animals the best physiological conditions, to minimize disturbance. The system has a heating table, the temperature of which can be adapted; and anesthesia is performed with gas or injection, for your convenience. And with the new In Actio imaging mode, you can even get rid of anesthesia, if this is compatible with your protocols!
Applications of the Photon Imager in Stem Cell Research
Survival and homing capacity of bone marrow-derived stromal cells in hind limb ischemia Poster presented at EMIM 2009
A mouse model of peripheral tissue ischemia was used to study
(i) the survival of transplanted allogeneic bone marrow-derived stromal cells (BMSCs), and
(ii) the homing capacity of allogeneic BMSC towards an ischemically compromized hind limb.
BMSCs2 (FVB origin) were injected into male C57BL/6 mice after surgical ligation of the left femoral artery.
Progenitor cells were injected either intravenously (IV), intra-arterially into the left heart ventricle or intramuscularly (IM) into the calf muscle.
Cell homing was studied with whole optical imaging and in vivo fibered microscopy. Poster presented at EMIM 2009
Courtesy of Dr. B Everaert, University of Antwerp, Vaccine and Infectious Disease Institute, Laboratory of Experimental Hematology, Antwerp, Belgium
Fluorescence imaging of neuronal precurors
Neuron precursors migrate from the subventricular zone to the olfactory bulb in the mouse brain (left mouse). The acquisition was performed without craniotomy, the cells could be detected through the skull of the animal, after shaving.
The right mouse was used as control.
Courtesy of Dr. Couillard Desprès and Pr. L. Aigner, University of Regensburg, Germany.
Neuron precursors migrate from the subventricular zone to the olfactory bulb in the mouse brain (left mouse). The acquisition was performed without craniotomy, the cells could be detected through the skull of the animal, after shaving.
The right mouse was used as control.
Courtesy of Dr. Couillard Desprès and Pr. L. Aigner, University of Regensburg, Germany.
Fluorescence imaging of neuronal precurors
The acquisition focused on the signal of the mouse brain; the signal was co-registered with a mouse brain photography for co-localization. The detected signal is consistent with the presence of large number of fluorescent neuron precursors in the subventricular zone and in the olfactory bulb.
Courtesy of Dr. Couillard Desprès and Pr. L. Aigner, University of Regensburg, Germany.
The acquisition focused on the signal of the mouse brain; the signal was co-registered with a mouse brain photography for co-localization. The detected signal is consistent with the presence of large number of fluorescent neuron precursors in the subventricular zone and in the olfactory bulb.
Courtesy of Dr. Couillard Desprès and Pr. L. Aigner, University of Regensburg, Germany.
Imaging of neuronal precurors in utero
The signal could be detected from neuron precursors in the developing brains of mouse embryos during the mouse pregnancy.
Dr. S. Couillard Despres and Pr. L. Aigner, Univ. Regensburg, Germany
The signal could be detected from neuron precursors in the developing brains of mouse embryos during the mouse pregnancy.
Dr. S. Couillard Despres and Pr. L. Aigner, Univ. Regensburg, Germany
Brain Imaging - Stem cell migration
C17.2 stem cells were inoculated in the left hemisphere of the brain of this mouse. C17.2 cells, a multipotent cell line, were derived from neonatal mouse cerebellum. Such cells have shown capability of integration in adult mouse neocortices that suffered from apoptotic degeneration. The cells could be imaged by means of bioluminescence imaging.
Courtesy of I. Que, E. Kajizel, C. Löwik, LUMC, Leiden, Netherlands
C17.2 stem cells were inoculated in the left hemisphere of the brain of this mouse. C17.2 cells, a multipotent cell line, were derived from neonatal mouse cerebellum. Such cells have shown capability of integration in adult mouse neocortices that suffered from apoptotic degeneration. The cells could be imaged by means of bioluminescence imaging.
Courtesy of I. Que, E. Kajizel, C. Löwik, LUMC, Leiden, Netherlands
