Contrast agents for photoacoustic imaging: a review of stem cell tracking

AbstractWith the advent of stem cell therapy for spinal cord injuries, stroke, burns, macular degeneration, heart diseases, diabetes, rheumatoid arthritis and osteoarthritis; the need to track the survival, migration pathways, spatial destination and differentiation of transplanted stem cells in a clinical setting has gained increased relevance. Indeed, getting regulatory approval to use these therapies in the clinic depends on biodistribution studies. Although optoacoustic imaging (OAI) or photoacoustic imaging can detect functional information of cell activities in real-time, the selection and application of suitable contrast agents is essential to achieve optimal sensitivity and contrast for sensing at clinically relevant depths and can even provide information about molecular activity. This review explores OAI methodologies in conjunction with the specific application of exogenous contrast agents in comparison to other imaging modalities and describes the properties of exogenous contrast agents for quantitative and qualitative monitoring of stem cells. Specific characteristics such as biocompatibility, the absorption coefficient, and surface functionalization are compared and how the labelling efficiency translates to both short and long-term visualization of mesenchymal stem cells is explored. An overview of novel properties of recently developed optoacoustic contrast agents and their capability to detect disease and recovery progression in clinical settings is provided which includes newly developed exogenous contrast agents to monitor stem cells in real-time for multimodal sensing.

Download Full-text

Abstract WMP75: Development of a Theragnostic Probe for Stem Cell Tracking and Enhancing the Therapeutic Efficacy in a Mouse Model of Focal Ischemia

Stroke ◽

10.1161/str.51.suppl_1.wmp75 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Xiaojing Shi ◽

Lu Zhang ◽

Zhijun Zhang ◽

Yongting Wang ◽

Guo-Yuan Yang ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Ischemic Stroke ◽

Mouse Model ◽

Cell Viability ◽

Brain Ischemia ◽

Therapeutic Efficacy ◽

Cell Tracking ◽

Photoacoustic Imaging

Objectives: Mesenchymal stem cell therapy has shown therapeutic potential for ischemic stroke. However, low cell viability and lack of multimodal imaging to track stem cell distribution limit its clinical translation. Here we developed a multifunctional probe to track stem cell viability and migration in a mouse model of focal brain ischemia. Methods: A theragnostic probe was developed by cobalt protoporphyrin IX (CoPP), with photoacoustic imaging detectability into 125 Iodine modified mesoporous silica nanoparticles ( 125 I-CoPP@MSN). The effect on cell viability and differentiation were examined in vitro . Adult male ICR mice (n=40) were subjected to 90 min transient middle cerebral artery occlusion. 125 I-CoPP@MSN labeled stem cells were transplanted into the peri-infarct region after 1 day of brain ischemia. Grafted cells was monitored by SPECT and photoacoustic imaging. The cell survival was evaluated by bioluminescence imaging. Results: 125 I-CoPP@MSNs have high efficiency for labeling cells without affecting their viability and differentiation. 125 I-CoPP@MSNs increased the viability of stem cells subjected to H 2 O 2 -induced oxidant stress in vitro , compared with controls ( p <0.05). Photoacoustic and SPECT imaging showed that 90±8% of graft cells were localized in the injection site and tended to migrate at 1 day after injection. The SPECT/CT signal started to decrease from 4 to 8 days. 125 I-CoPP@MSN labeling increased graft cell viability, reduced brain atrophy volume, and improved behavioral outcomes, compared to the controls ( p <0.05). Immunostaining results showed that the number of CD31 + and DCX + cells were increased in CoPP@MSN labeled group than that in controls (p<0.05). Conclusion: We conclude that 125 I-CoPP@MSNs is a novel probe for the real-time tracking and enhancing its therapeutic efficacy in ischemic stroke therapy.

Download Full-text

Improved biocompatibility and efficient labeling of neural stem cells with poly(L-lysine)-coated maghemite nanoparticles

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.7.84 ◽

2016 ◽

Vol 7 ◽

pp. 926-936 ◽

Cited By ~ 15

Author(s):

Igor M Pongrac ◽

Marina Dobrivojević ◽

Lada Brkić Ahmed ◽

Michal Babič ◽

Miroslav Šlouf ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Neural Stem Cells ◽

Cellular Uptake ◽

Cell Tracking ◽

Cellular Migration ◽

Cell Labeling ◽

Blue Staining ◽

Maghemite Nanoparticles ◽

Acetoxymethyl Ester

Background: Cell tracking is a powerful tool to understand cellular migration, dynamics, homing and function of stem cell transplants. Nanoparticles represent possible stem cell tracers, but they differ in cellular uptake and side effects. Their properties can be modified by coating with different biocompatible polymers. To test if a coating polymer, poly(L-lysine), can improve the biocompatibility of nanoparticles applied to neural stem cells, poly(L-lysine)-coated maghemite nanoparticles were prepared and characterized. We evaluated their cellular uptake, the mechanism of internalization, cytotoxicity, viability and proliferation of neural stem cells, and compared them to the commercially available dextran-coated nanomag®-D-spio nanoparticles. Results: Light microscopy of Prussian blue staining revealed a concentration-dependent intracellular uptake of iron oxide in neural stem cells. The methyl thiazolyl tetrazolium assay and the calcein acetoxymethyl ester/propidium iodide assay demonstrated that poly(L-lysine)-coated maghemite nanoparticles scored better than nanomag®-D-spio in cell labeling efficiency, viability and proliferation of neural stem cells. Cytochalasine D blocked the cellular uptake of nanoparticles indicating an actin-dependent process, such as macropinocytosis, to be the internalization mechanism for both nanoparticle types. Finally, immunocytochemistry analysis of neural stem cells after treatment with poly(L-lysine)-coated maghemite and nanomag®-D-spio nanoparticles showed that they preserve their identity as neural stem cells and their potential to differentiate into all three major neural cell types (neurons, astrocytes and oligodendrocytes). Conclusion: Improved biocompatibility and efficient cell labeling makes poly(L-lysine)-coated maghemite nanoparticles appropriate candidates for future neural stem cell in vivo tracking studies.

Download Full-text

Systematic Intracellular Biocompatibility Assessments of Superparamagnetic Iron Oxide Nanoparticles in Human Umbilical Cord Mesenchyme Stem Cells in Testifying Its Reusability for Inner Cell Tracking by MRI

Journal of Biomedical Nanotechnology ◽

10.1166/jbn.2019.2845 ◽

2019 ◽

Vol 15 (11) ◽

pp. 2179-2192

Author(s):

Yuanyuan Xie ◽

Wei Liu ◽

Bing Zhang ◽

Bin Wang ◽

Liudi Wang ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Umbilical Cord ◽

Cell Tracking ◽

Superparamagnetic Iron Oxide ◽

Human Umbilical Cord ◽

Cell Based Therapy

Until now, there is no effective method for tracking transplanted stem cells in human. Ruicun (RC) is a new ultra-small SPIONs agent that has been approved by China Food and Drug Administration for iron supplementation but not as a stem cell tracer in clinic. In this study, we demonstrated magnetic resonance imaging-based tracking of RC-labeled human umbilical cord derived mesenchymal stem cells (MSCs) transplanted to locally injured site of rat spinal cords. We then comprehensively evaluated the safety and quality of the RC-labeled MSCs under good manufacturing practicecompliant conditions, to investigate the feasibility of SPIONs for inner tracking in stem cell-based therapy (SCT). Our results showed that RC labeling at appropriate dose (200 μg/mL) did not have evident impacts on characteristics of MSCs in vitro, demonstrating safety, non-carcinogenesis, and non-tissue inflammation in vivo. The systematic assessments of intracellular biocompatibility indicated that the RC labeled MSCs met with mandatory requirements and standards for law-regulation systems regarding SCT, facilitating translation of cell-tracking technologies to clinical trials.

Download Full-text

Clonal Compensation Between Hematopoietic Stem Cells upon Differentiation Deficiency

Blood ◽

10.1182/blood.v128.22.422.422 ◽

2016 ◽

Vol 128 (22) ◽

pp. 422-422

Author(s):

Rong Lu ◽

Lisa Nguyen

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Blood Cell ◽

Cell Tracking ◽

Conflicts Of Interest ◽

Genetically Modified ◽

Cell Types ◽

Clonal Expansion ◽

Hematopoietic Stem ◽

Organ Systems

Abstract In most organ systems, regeneration is a coordinated effort that involves many stem cells, but little is known about how individual stem cells compensate for the functional deficiencies of other stem cells. Functional coordination between stem cells is critically important during disease progression and treatment when a subset of HSCs fail or become malignant. We hypothesize that individual HSCs heterogeneously compensate for specific deficiencies, as recent work from our group and others suggest that HSCs heterogeneously supply blood. To test this hypothesis, we tracked mouse HSCs in vivo using a single-cell tracking technology that we had previously developed. We found that individual HSCs heterogeneously compensate for the lymphopoiesis deficiencies of other HSCs by increasing individual clonal expansion and altering lineage bias. Clonal expansion refers to the increase in clonal progenies. Lineage bias refers to the preferential production of specific blood cell types. This compensation rescues the overall blood supply and influences blood cell types outside of the deficient lineages in distinct patterns. We identified the molecular regulators and signaling pathways associated with this form of HSC coordination using RNA sequencing. Specifically, the STAT3 pathway and NF-B signalingwere activated, and PTEN signaling was inhibited in HSCs during the compensation process. To investigate the dynamics of HSC coordination, we employed a genetically modified mouse model that expresses simian diphtheria toxin (DT) receptor under the control of the CD11b promoter. Monocytes derived from this mouse line can be ablated upon DT administration. We co-transplanted HSCs derived from normal and the genetically modified mice, then conditionally ablated the monocyte population repeatedly, and tracked the temporal responses of individual normal HSCs. Our time-course analysis revealed that a distinct subset of HSC clones produced rapid and persistent responses to the blood perturbations. These clones had not been highly active in the affected lineages prior to the perturbation. We identified several significant temporal profiles that indicate a remarkable heterogeneity in the responses of HSCs to blood system changes. Together, these data suggest that HSC differentiation is coordinated in a deterministic manner during compensation and is independent of the normal differentiation program. Our findings suggest that stem cells interact with each other and form a coordinated cellular network that is robust enough to withstand minor functional disruptions. Individual HSCs distinctly adapt their differentiation program to compensate for deficient HSCs and specifically overproduce undersupplied cell types. The heterogeneity in the compensation activities of individual HSC clones may be essential for maintaining robustness in blood regeneration and suggests that stem cell coordination is a complex process. A better understanding of the clonal level differences in individual HSCs is critically important for identifying the pathogenesis of blood diseases. Exploiting the innate compensation capacity of stem cell networks may improve the diagnosis and treatment of many diseases. For example, the identification of the molecular regulators and pathways involved in HSC compensation can help develop new therapeutic treatments that enhance the innate compensation capacity of stem cells. Disclosures No relevant conflicts of interest to declare.

Download Full-text

An Efficient In Vitro Culture System To Amplify Spermatogonia Stem Cell Markers

Research in Molecular Medicine ◽

10.32598/rmm.8.3.2 ◽

2020 ◽

Vol 8 (3) ◽

pp. 117-124

Author(s):

Zeinab Narimanpour ◽

◽

Maryam Nazm Bojnordi ◽

Hatef Ghasemi ◽

◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Real Time ◽

Cultured Cells ◽

Expression Level ◽

Stem Cell Markers ◽

Testicular Cells ◽

Spermatogonia Stem Cell ◽

Alteration Pattern

Introduction: Proliferation of spermatogonial stem cells (SSCs) can be a treatment for infertile men. Here, we design an efficient method based on culturing in the presence of Sertoli cells to improve the expression level of some specific spermatogonia stem cell genes during two weeks post culture. Materials and Methods: Cells were derived from neonatal (2-6 days old) mice testes and were cultured in DMEM medium with FBS. The colonization of cultured SSCs in days 4, 7, and 14 of culture was counted via phase-contrast microscope and Image J software. Methyl thiazolyl tetrazolium (MTT) test was performed to evaluate the viability of cultured SSCs in days 3, 7, and 14 of culture. The expression level and the alteration pattern of specific spermatogonial markers, i.e., Stra8, DAZL, and Piwill2 was examined via real-time polymerase chain reaction (PCR) during two weeks post culture. Results: The number and the diameters of colonies showed a significant increase in cultured cells. MTT results proved the higher viability of testicular cells during the culture period. The results of ALP staining detected a positive reaction in spermatogonia colonies. Real-time PCR data showed that culturing SSCs in the presence of interstitial cells of the testis, amplified the level and alteration pattern of specific spermatogonia stem cells genes beneficial in the enrichment of SSCs propagation. Conclusion: Providing a similar culture environment to testicular niche increases viability, forms SSCs colonies, and regulates the level and alteration pattern of spermatogonia stem cell genes.

Download Full-text

Combined Analysis of Endothelial, Hematopoietic, and Mesenchymal Stem Cell Compartments Shows Simultaneous but Independent Effects of Age and Heart Disease

Stem Cells International ◽

10.1155/2017/5237634 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Carine Ghem ◽

Lucinara Dadda Dias ◽

Roberto Tofani Sant’Anna ◽

Renato A. K. Kalil ◽

Melissa Markoski ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Heart Disease ◽

Cell Therapy ◽

Progenitor Cells ◽

Heart Diseases ◽

Left Ventricular ◽

Syntax Score ◽

Hematopoietic Stem ◽

Cell Compartments

Clinical trials using stem cell therapy for heart diseases have not reproduced the initial positive results obtained with animal models. This might be explained by a decreased regenerative capacity of stem cells collected from the patients. This work aimed at the simultaneous investigation of endothelial stem/progenitor cells (EPCs), mesenchymal stem/progenitor cells (MSCs), and hematopoietic stem/progenitor cells (HSCs) in sternal bone marrow samples of patients with ischemic or valvular heart disease, using flow cytometry and colony assays. The study included 36 patients referred for coronary artery bypass grafting or valve replacement surgery. A decreased frequency of stem cells was observed in both groups of patients. Left ventricular dysfunction, diabetes, and intermediate risk in EuroSCORE and SYNTAX score were associated with lower EPCs frequency, and the use of aspirin andβ-blockers correlated with a higher frequency of HSCs and EPCs, respectively. Most importantly, the distribution of frequencies in the three stem cell compartments showed independent patterns. The combined investigation of the three stem cell compartments in patients with cardiovascular diseases showed that they are independently affected by the disease, suggesting the investigation of prognostic factors that may be used to determine when autologous stem cells may be used in cell therapy.

Download Full-text

Highly efficient cellular labeling of mesoporous nanoparticles in human mesenchymal stem cells: implication for stem cell tracking

The FASEB Journal ◽

10.1096/fj.05-4288fje ◽

2005 ◽

Vol 19 (14) ◽

pp. 2014-2016 ◽

Cited By ~ 141

Author(s):

Dong‐Ming Huang ◽

Yann Hung ◽

Bor‐Sheng Ko ◽

Szu‐Chun Hsu ◽

Wei‐Hsuan Chen ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Cell Tracking ◽

Human Mesenchymal Stem Cells ◽

Stem Cell Tracking ◽

Highly Efficient ◽

Cellular Labeling ◽

Mesoporous Nanoparticles

Download Full-text

Endothelial Nitric Oxide Synthase Knockdown in Human Stem Cells Impacts Mitochondrial Biogenesis and Adipogenesis: Live-Cell Real-Time Fluorescence Imaging

Journal of Clinical Medicine ◽

10.3390/jcm10040631 ◽

2021 ◽

Vol 10 (4) ◽

pp. 631

Author(s):

Sylvia Lee-Huang ◽

Philip Lin Huang ◽

Paul Lee Huang

Keyword(s):

Nitric Oxide ◽

Stem Cells ◽

Stem Cell ◽

Nitric Oxide Synthase ◽

Real Time ◽

Mitochondrial Biogenesis ◽

Endothelial Nitric Oxide Synthase ◽

Live Cell ◽

Oxide Synthase ◽

Endothelial Nitric Oxide

We carried out live-cell real-time fluorescence imaging to follow the effects of genetic (siRNA) knockdown (KD) of endothelial nitric oxide synthase (eNOS) on mitochondrial biogenesis and adipogenesis in human mesenchymal stem cells (hMSCs). We report here that eNOS KD in hMSCs blocks mitochondrial biogenesis and adipogenesis. The transfer of mitochondria from normal hMSCs to eNOS-deficient hMSCs restores adipogenesis. Furthermore, cell-free mitochondria purified from normal hMSCs also restores adipogenesis in eNOS-deficient cells. Thus, eNOS and NO signaling are essential for mitochondrial biogenesis, and mitochondrial activity is indispensable for adipogenesis in hMSC differentiation. We mapped the path and identified the mechanisms of mitochondrial transfer. We captured real-time images of differentiated mature adipocytes in mitosis and replication. These results reveal that human stem cell-differentiated fat cells are capable of replication. This new finding offers novel insights into our understanding of fat cell expansion and the development of obesity. Real-time imaging in live cells allows synchronized investigation of mitochondrial biogenesis and adipogenesis in stem cell differentiation without reducing living cells to nonliving samples for functional analysis. Live-cell real-time imaging can thus be a faithful and immediate tool for molecular diagnostic medicine. Furthermore, our results suggest that mitochondrial remodeling can be a useful approach in treating adiposity, diabetes, and abnormalities in energy metabolism and vascular signaling.

Download Full-text

Polymer-Peptide Modified Gold Nanorods to Improve Cell Conjugation and Cell labelling for Stem Cells Photoacoustic Imaging

Diagnostics ◽

10.3390/diagnostics11071196 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1196

Author(s):

Dina Salah ◽

Farahat S. Moghanm ◽

Muhammad Arshad ◽

Abdulaziz A. Alanazi ◽

Salman latif ◽

...

Keyword(s):

Stem Cells ◽

Contrast Agent ◽

Surface Plasmon ◽

Cellular Uptake ◽

Gold Nanorods ◽

Cell Tracking ◽

Photoacoustic Imaging ◽

Optical Measurements ◽

Peptide Sequence ◽

Ammonium Bromide

The use of gold nanorods (GNRs) as a contrast agent in bioimaging and cell tracking has numerous advantages, primarily due to the unique optical properties of gold nanorods which allow for the use of infrared regions when imaging. Owing to their unique geometry, Au NRs exhibit surface plasmon modes in the near-infrared wavelength range, which is ideal for carrying out optical measurements in biological fluids and tissue. Gold nanorod functionalization is essential, since the Cetyltrimethyl ammonium bromide CTAB gold nanorods are toxic, and for further in vitro and in vivo experiments the nanorods should be functionalized to become optically stable and biocompatible. In the present study, gold nanorods with an longitudinal surface plasmon resonance (LSPR) position around 800 nm were synthesized in order to be used for photoacoustic imaging applications for stem cell tracking. The gold nanorods were functionalized using both thiolated poly (ethylene glycol) (PEG) to stabilize the gold nanorods surface and a CALNN–TAT peptide sequence. Both ligands were attached to the gold nanorods through an Au–sulfur bond. CALNN–TAT is known as a cell penetrating peptide which ensures endocytosis of the gold nanorods inside the mesenchymal stem cells of mice (MSCD1). Surface modifications of gold nanorods were achieved using optical spectroscopy (UV–VIS), electron microscopy (TEM), zeta-potential, and FTIR. Gold nanorods were incubated in MSCD1 in order to achieve a cellular uptake that was characterized by a transmission electron microscope (TEM). For photoacoustic imaging, Multi-Spectral Optoacoustic Tomography (MSOT) was used. The results demonstrated good cellular uptake for PEG–CALNN–TAT GNRs and the successful use of modified gold nanorods as both a contrast agent in photoacoustic imaging and as a novel tracking bioimaging technique.

Download Full-text

Current status, challenges and perspectives of mesenchymal stem cell-based therapy for cardiac regeneration

Complex Issues of Cardiovascular Diseases ◽

10.17802/2306-1278-2021-10-3-72-78 ◽

2021 ◽

Vol 10 (3) ◽

pp. 72-78

Author(s):

P. M. Docshin ◽

A. Bairqdar ◽

A. B. Malashicheva

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Therapy ◽

Side Population ◽

Heart Diseases ◽

Systolic Pressure ◽

Left Ventricular ◽

Individual Characteristics ◽

Current Status ◽

Cell Based Therapy

Modern methods of treating heart failure are similar to the palliative care, since they mostly relieve the symptoms of the disease. The discovery of resident cardiac stem cells gave impetus to the development of “second generation” cell therapy, which quickly moved from animal research to clinical trials with critically ill patients. Many cardiac side population cells have been identified to have stem cells characteristics and some additional individual characteristics, both in vitro and in vivo. The results of clinical studies demonstrated that the stem cell treatment is safe, however, this type of cell-based therapy did not restore cardiac function. Its effects were limited to mildly improving left ventricular systolic pressure and reducing the scar area. Despite that, the promising nature of these therapeutic approaches for heart diseases have contributed to the development of next-generation cell therapy.

Download Full-text