Automated segmentation and tracking of cells in actively developing tissues can provide high-throughput and quantitative spatiotemporal measurements of a range of cell behaviors; cell expansion and cell-division kinet...Automated segmentation and tracking of cells in actively developing tissues can provide high-throughput and quantitative spatiotemporal measurements of a range of cell behaviors; cell expansion and cell-division kinetics leading to a better understanding of the underlying dynamics of morphogenesis. Here, we have studied the problem of constructing cell lineages in time-lapse volumetric image stacks obtained using Confocal Laser Scanning Microscopy （CLSM）. The novel contribution of the work lies in its ability to segment and track cells in densely packed tissue, the shoot apical meristem （SAM）, through the use of a close-loop, adaptive segmentation, and tracking approach. The tracking output acts as an indicator of the quality of segmentation and, in turn, the segmentation can be improved to obtain better tracking results. We construct an optimization function that minimizes the segmentation error, which is, in turn, estimated from the tracking results. This adaptive approach significantly improves both tracking and segmentation when compared to an open loop framework in which segmentation and tracking modules operate separately.展开更多
Background and Aims:Stem cell transplantation is a potential treatment option for liver cirrhosis(LC).Accurately and noninvasively monitoring the distribution,migration,and prognosis of transplanted stem cells using i...Background and Aims:Stem cell transplantation is a potential treatment option for liver cirrhosis(LC).Accurately and noninvasively monitoring the distribution,migration,and prognosis of transplanted stem cells using imaging methods is important for in-depth study of the treatment mechanisms.Our study aimed to develop Au-Fe3O4 silica nanoparticles(NPs)as tracking nanoplatforms for dualmodal stem cell imaging.Methods:Au-Fe3O4 silica NPs were synthesized by seed-mediated growth method and co-precipitation.The efficiency and cytotoxicity of the NPslabeled bone marrow-derived mesenchymal stem cells(BMMSCs)were evaluated by Cell Counting Kit-8 assays,ICPMS,phenotypic characterization,and histological staining.The biodistribution of labeled BM-MSCs injected through different routes(the hepatic artery or tail vein)into rats with LC was detected by magnetic resonance imaging(MRI),photoacoustic imaging(PAI),and Prussian blue staining.Results:Synthesized Au-Fe3O4 silica NPs consisted of a core(star-shaped Au NPs)and an outside silica layer doped with Fe3O4 NPs.After 24 h coincubation with 2.0 OD concentration of NPs,the viability of BM-MSCs was 77.91%±5.86%and the uptake of Au and Fe were(22.65±1.82)µg/mL and(234.03±11.47)µg/mL,respectively.The surface markers of labeled BM-MSCs unchanged significantly.Labeled BMMSCs have osteogenic and adipogenic differentiation potential.Post injection in vivo,rat livers were hypointense on MRI and hyperintense on PAI.Prussian blue staining showed that more labeled BM-MSCs accumulated in the liver of the hepatic artery group.The severity of LC of the rats in the hepatic artery group was significantly alleviated.Conclusions:Au-Fe3O4 silica NPs were suitable MRI/PAI dual-modal imaging nanoplatforms for stem cell tracking in regenerative medicine. Transhepatic arterial infusion of BMMSCs was the optimal route for the treatment of LC.展开更多
Low back pain is a common clinical problem, which leads to significant social, economic and public health costs. Intervertebral disc(IVD) degeneration is accepted as a common cause of low back pain. Initially, this is...Low back pain is a common clinical problem, which leads to significant social, economic and public health costs. Intervertebral disc(IVD) degeneration is accepted as a common cause of low back pain. Initially, this is characterized by a loss of proteoglycans from the nucleus pulposus resulting in loss of tissue hydration and hydrostatic pressure. Conservative management,including analgesia and physiotherapy often fails and surgical treatment, such as spinal fusion, is required. Stem cells offer an exciting possible regenerative approach to IVD disease. Preclinical research has demonstrated promising biochemical, histological and radiological results in restoring degenerate IVDs. Cell tracking provides an opportunity to develop an in-depth understanding of stem cell survival, differentiation and migration, enabling optimization of stem cell treatment. Magnetic Resonance Imaging(MRI) is a non-invasive, non-ionizing imaging modality with high spatial resolution, ideally suited for stem cell tracking. Furthermore, novel MRI sequences have the potential to quantitatively assess IVD disease, providing an improved method to review response to biological treatment. Superparamagnetic iron oxide nanoparticles have been extensively researched for the purpose of cell tracking. These particles are biocompatible, non-toxic and act as excellent MRI contrast agents. This review will explore recent advances and issues in stem cell tracking and molecular imaging in relation to the IVD.展开更多
Therapies based on stem cell transplants offer significant potential in the field of regenerative medicine. Monitoring the fate of the transplanted stem cells in a timely manner is considered one of the main limitatio...Therapies based on stem cell transplants offer significant potential in the field of regenerative medicine. Monitoring the fate of the transplanted stem cells in a timely manner is considered one of the main limitations for long-standing success of stem cell transplants. Imaging methods that visualize and track stem cells<i> in vivo</i> non-invasively in real time are helpful towards the development of successful cell transplantation techniques. Novel molecular imaging methods which are non-invasive particularly such as MRI have been of great recent interest. Hence, mouse models which are of clinical relevance have been studied by injecting contrast agents used for labelling cells such as super-paramagnetic iron-oxide (SPIO) nanoparticles for cellular imaging. The MR techniques which can be used to generate positive contrast images have been of much relevance recently for tracking of the labelled cells. Particularly when the off-resonance region in the vicinity of the labeled cells is selectively excited while suppressing the signals from the non-labeled regions by the method of spectral dephasing. Thus, tracking of magnetically labelled cells employing positive contrast<i> in vivo</i> MR imaging methods in a burn mouse model in a non-invasive way has been the scope of this study. The consequences have direct implications for monitoring labeled stem cells at some stage in wound healing. We suggest that our approach can be used in clinical trials in molecular and regenerative medicine.展开更多
BACKGROUND Stroke is the second leading cause of death worldwide.There is a real need to develop treatment strategies for reducing neurological deficits in stroke survivors,and stem cell(SC)therapeutics appear to be a...BACKGROUND Stroke is the second leading cause of death worldwide.There is a real need to develop treatment strategies for reducing neurological deficits in stroke survivors,and stem cell(SC)therapeutics appear to be a promising alternative for stroke therapy that can be used in combination with approved thrombolytic or thrombectomy approaches.However,the efficacy of SC therapy depends on the SC homing ability and engraftment into the injury site over a long period of time.Nonetheless,tracking SCs from their niche to the target tissues is a complex process.AIM To evaluate SC migration homing,tracking and therapeutic efficacy in the treatment of stroke using nanoparticles METHODS A systematic literature search was performed to identify articles published prior to November 2019 that were indexed in PubMed and Scopus.The following inclusion criteria were used:(1)Studies that used in vivo models of stroke or ischemic brain lesions;(2)Studies of SCs labeled with some type of contrast agent for cell migration detection;and(3)Studies that involved in vivo cellular homing and tracking analysis.RESULTS A total of 82 articles were identified by indexing in Scopus and Pub Med.Afterthe inclusion criteria were applied,35 studies were selected,and the articles were assessed for eligibility;ultimately,only 25 studies were included.Most of the selected studies used SCs from human and mouse bone marrow labeled with magnetic nanoparticles alone or combined with fluorophore dyes.These cells were administered in the stroke model(to treat middle cerebral artery occlusion in 74%of studies and for photothrombotic induction in 26%of studies).Fiftythree percent of studies used xenogeneic grafts for cell therapy,and the migration homing and tracking evaluation was performed by magnetic resonance imaging as well as other techniques,such as near-infrared fluorescence imaging(12%)or bioluminescence assays(12%).CONCLUSION Our systematic review provided an up-to-date evaluation of SC migration homing and the efficacy of cellular therapy for str展开更多
文摘Automated segmentation and tracking of cells in actively developing tissues can provide high-throughput and quantitative spatiotemporal measurements of a range of cell behaviors; cell expansion and cell-division kinetics leading to a better understanding of the underlying dynamics of morphogenesis. Here, we have studied the problem of constructing cell lineages in time-lapse volumetric image stacks obtained using Confocal Laser Scanning Microscopy （CLSM）. The novel contribution of the work lies in its ability to segment and track cells in densely packed tissue, the shoot apical meristem （SAM）, through the use of a close-loop, adaptive segmentation, and tracking approach. The tracking output acts as an indicator of the quality of segmentation and, in turn, the segmentation can be improved to obtain better tracking results. We construct an optimization function that minimizes the segmentation error, which is, in turn, estimated from the tracking results. This adaptive approach significantly improves both tracking and segmentation when compared to an open loop framework in which segmentation and tracking modules operate separately.
基金funded by grants from The National Natural Science Foundation of China (No.81671800)。
文摘Background and Aims:Stem cell transplantation is a potential treatment option for liver cirrhosis(LC).Accurately and noninvasively monitoring the distribution,migration,and prognosis of transplanted stem cells using imaging methods is important for in-depth study of the treatment mechanisms.Our study aimed to develop Au-Fe3O4 silica nanoparticles(NPs)as tracking nanoplatforms for dualmodal stem cell imaging.Methods:Au-Fe3O4 silica NPs were synthesized by seed-mediated growth method and co-precipitation.The efficiency and cytotoxicity of the NPslabeled bone marrow-derived mesenchymal stem cells(BMMSCs)were evaluated by Cell Counting Kit-8 assays,ICPMS,phenotypic characterization,and histological staining.The biodistribution of labeled BM-MSCs injected through different routes(the hepatic artery or tail vein)into rats with LC was detected by magnetic resonance imaging(MRI),photoacoustic imaging(PAI),and Prussian blue staining.Results:Synthesized Au-Fe3O4 silica NPs consisted of a core(star-shaped Au NPs)and an outside silica layer doped with Fe3O4 NPs.After 24 h coincubation with 2.0 OD concentration of NPs,the viability of BM-MSCs was 77.91%±5.86%and the uptake of Au and Fe were(22.65±1.82)µg/mL and(234.03±11.47)µg/mL,respectively.The surface markers of labeled BM-MSCs unchanged significantly.Labeled BMMSCs have osteogenic and adipogenic differentiation potential.Post injection in vivo,rat livers were hypointense on MRI and hyperintense on PAI.Prussian blue staining showed that more labeled BM-MSCs accumulated in the liver of the hepatic artery group.The severity of LC of the rats in the hepatic artery group was significantly alleviated.Conclusions:Au-Fe3O4 silica NPs were suitable MRI/PAI dual-modal imaging nanoplatforms for stem cell tracking in regenerative medicine. Transhepatic arterial infusion of BMMSCs was the optimal route for the treatment of LC.
文摘Low back pain is a common clinical problem, which leads to significant social, economic and public health costs. Intervertebral disc(IVD) degeneration is accepted as a common cause of low back pain. Initially, this is characterized by a loss of proteoglycans from the nucleus pulposus resulting in loss of tissue hydration and hydrostatic pressure. Conservative management,including analgesia and physiotherapy often fails and surgical treatment, such as spinal fusion, is required. Stem cells offer an exciting possible regenerative approach to IVD disease. Preclinical research has demonstrated promising biochemical, histological and radiological results in restoring degenerate IVDs. Cell tracking provides an opportunity to develop an in-depth understanding of stem cell survival, differentiation and migration, enabling optimization of stem cell treatment. Magnetic Resonance Imaging(MRI) is a non-invasive, non-ionizing imaging modality with high spatial resolution, ideally suited for stem cell tracking. Furthermore, novel MRI sequences have the potential to quantitatively assess IVD disease, providing an improved method to review response to biological treatment. Superparamagnetic iron oxide nanoparticles have been extensively researched for the purpose of cell tracking. These particles are biocompatible, non-toxic and act as excellent MRI contrast agents. This review will explore recent advances and issues in stem cell tracking and molecular imaging in relation to the IVD.
文摘Therapies based on stem cell transplants offer significant potential in the field of regenerative medicine. Monitoring the fate of the transplanted stem cells in a timely manner is considered one of the main limitations for long-standing success of stem cell transplants. Imaging methods that visualize and track stem cells<i> in vivo</i> non-invasively in real time are helpful towards the development of successful cell transplantation techniques. Novel molecular imaging methods which are non-invasive particularly such as MRI have been of great recent interest. Hence, mouse models which are of clinical relevance have been studied by injecting contrast agents used for labelling cells such as super-paramagnetic iron-oxide (SPIO) nanoparticles for cellular imaging. The MR techniques which can be used to generate positive contrast images have been of much relevance recently for tracking of the labelled cells. Particularly when the off-resonance region in the vicinity of the labeled cells is selectively excited while suppressing the signals from the non-labeled regions by the method of spectral dephasing. Thus, tracking of magnetically labelled cells employing positive contrast<i> in vivo</i> MR imaging methods in a burn mouse model in a non-invasive way has been the scope of this study. The consequences have direct implications for monitoring labeled stem cells at some stage in wound healing. We suggest that our approach can be used in clinical trials in molecular and regenerative medicine.
基金Supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico(BR),No.CNPq400856/2016-6Sao Paulo State Research Support Foundation,No.FAPESP:2014/50983-3 and No.FAPESP:2016/21470-3。
文摘BACKGROUND Stroke is the second leading cause of death worldwide.There is a real need to develop treatment strategies for reducing neurological deficits in stroke survivors,and stem cell(SC)therapeutics appear to be a promising alternative for stroke therapy that can be used in combination with approved thrombolytic or thrombectomy approaches.However,the efficacy of SC therapy depends on the SC homing ability and engraftment into the injury site over a long period of time.Nonetheless,tracking SCs from their niche to the target tissues is a complex process.AIM To evaluate SC migration homing,tracking and therapeutic efficacy in the treatment of stroke using nanoparticles METHODS A systematic literature search was performed to identify articles published prior to November 2019 that were indexed in PubMed and Scopus.The following inclusion criteria were used:(1)Studies that used in vivo models of stroke or ischemic brain lesions;(2)Studies of SCs labeled with some type of contrast agent for cell migration detection;and(3)Studies that involved in vivo cellular homing and tracking analysis.RESULTS A total of 82 articles were identified by indexing in Scopus and Pub Med.Afterthe inclusion criteria were applied,35 studies were selected,and the articles were assessed for eligibility;ultimately,only 25 studies were included.Most of the selected studies used SCs from human and mouse bone marrow labeled with magnetic nanoparticles alone or combined with fluorophore dyes.These cells were administered in the stroke model(to treat middle cerebral artery occlusion in 74%of studies and for photothrombotic induction in 26%of studies).Fiftythree percent of studies used xenogeneic grafts for cell therapy,and the migration homing and tracking evaluation was performed by magnetic resonance imaging as well as other techniques,such as near-infrared fluorescence imaging(12%)or bioluminescence assays(12%).CONCLUSION Our systematic review provided an up-to-date evaluation of SC migration homing and the efficacy of cellular therapy for str
