MR tracking of SPIO-labeled mesenchymal stem cells in rats with liver fibrosis could not monitor the cells accurately

Optimal technique for canine mesenchymal stem cells labeling with novel SPIO, MIRB™: for MRI detection of transplanted stem cells canine stroke model

BACKGROUND

Cell-based therapy has emerged as a promising avenue for post-stroke recovery. A significant challenge lies in tracking the distribution and engraftment of transplanted cells within the target cerebral tissue. To address this, we turn to the potential of Brain MRI detection of mesenchymal stem cells (MSCs), achieved by labeling these cells with superparamagnetic iron oxide (SPIO). This is the first report of a technique to label canine MSCs using a commercially available SPIO, Molday ION Rhodamine B (MIRB), to optimize both viability and labeling efficacy for transplantation purposes."

METHOD

Canine MSCs were incubated with addition of different MIRB concentration from 0, 10, 20, 30 μg Fe/ml. The cellular uptake of MIRB was confirmed through the analysis of fluorescent images and flow cytometry. The morphological characteristics of MSCs were assessed via microscopic visualization. Cellular viability was evaluated using both a cellometer and flow cytometry.

RESULT

Fluorescent microscopic images of all MIRB incubated MSCs groups show >70% labeled cells with homogenous signal intensity. Notably, the morphology of MSCs remained unaltered in the 10 μg Fe/ml group compared to the control group. Furthermore, among the labeled groups, the 10 μg Fe/ml concentration exhibited the highest viability when assessed using two different flow cytometry methods (95.3%, p < 0.05).

CONCLUSION

This study successfully labels canine MSCs with MIRB. The optimal concentration of 10 μg Fe/ml demonstrates optimal viability, labeling efficacy, and preserved cellular morphology.

Tracking of Stem Cells in Chronic Liver Diseases: Current Trends and Developments

Stem cell therapy holds great promise for future clinical practice for treatment of advanced liver diseases. However, the fate of stem cells after transplantation, including the distribution, viability, and the cell clearance, has not been fully elucidated. Herein, recent advances regarding the imaging tools for stem cells tracking mainly in chronic liver diseases with the advantages and disadvantages of each approach have been described. Magnetic resonance imaging is a promising clinical imaging modality due to non-radioactivity, excellent penetrability, and high spatial resolution. Fluorescence imaging and radionuclide imaging demonstrate relatively increased sensitivity, with the latter excelling in real-time monitoring. Reporter genes specialize in long-term tracing. Nevertheless, the disadvantages of low sensitivity, radiation, exogenous gene risk are inevitably present in each of these means, respectively. In this review, we aim to comprehensively evaluate the current state of methods for tracking of stem cell, highlighting their strengths and weaknesses, and providing insights into their future potential. Multimodality imaging strategies may overcome the inherent limitations of single-modality imaging by combining the strengths of different imaging techniques to provide more comprehensive information in the clinical setting.

MRI/PAI Dual-modal Imaging-guided Precise Tracking of Bone Marrow-derived Mesenchymal Stem Cells Labeled with Nanoparticles for Treating Liver Cirrhosis

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 dual-modal stem cell imaging.

METHODS

Au-Fe₃O₄ silica NPs were synthesized by seed-mediated growth method and co-precipitation. The efficiency and cytotoxicity of the NPs-labeled bone marrow-derived mesenchymal stem cells (BM-MSCs) were evaluated by Cell Counting Kit-8 assays, ICP-MS, 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 BM-MSCs 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 BM-MSCs was the optimal route for the treatment of LC.

Impact of Nanotechnology on Differentiation and Augmentation of Stem Cells for Liver Therapy

The liver is one of the crucial organs of the body that performs hundreds of chemical reactions needed by the body to survive. It is also the largest gland of the body. The liver has multiple functions, including the synthesis of chemicals, metabolism of nutrients, and removal of toxins. It also acts as a storage unit. The liver has a unique ability to regenerate itself, but it can lead to permanent damage if the injury is beyond recovery. The only possible treatment of severe liver damage is liver transplant which is a costly procedure and has several other drawbacks. Therefore, attention has been shifted towards the use of stem cells that have shown the ability to differentiate into hepatocytes. Among the numerous kinds of stem cells (SCs), the mesenchymal stem cells (MSCs) are the most famous. Various studies suggest that an MSC transplant can repair liver function, improve the signs and symptoms, and increase the chances of survival. This review discusses the impact of combining stem cell therapy with nanotechnology. By integrating stem cell science and nanotechnology, the information about stem cell differentiation and regulation will increase, resulting in a better comprehension of stem cell-based treatment strategies. The augmentation of SCs with nanoparticles has been shown to boost the effect of stem cell-based therapy. Also, the function of green nanoparticles in liver therapies is discussed.

Iron Oxide Nanoparticles in Regenerative Medicine and Tissue Engineering

In recent years, many promising nanotechnological approaches to biomedical research have been developed in order to increase implementation of regenerative medicine and tissue engineering in clinical practice. In the meantime, the use of nanomaterials for the regeneration of diseased or injured tissues is considered advantageous in most areas of medicine. In particular, for the treatment of cardiovascular, osteochondral and neurological defects, but also for the recovery of functions of other organs such as kidney, liver, pancreas, bladder, urethra and for wound healing, nanomaterials are increasingly being developed that serve as scaffolds, mimic the extracellular matrix and promote adhesion or differentiation of cells. This review focuses on the latest developments in regenerative medicine, in which iron oxide nanoparticles (IONPs) play a crucial role for tissue engineering and cell therapy. IONPs are not only enabling the use of non-invasive observation methods to monitor the therapy, but can also accelerate and enhance regeneration, either thanks to their inherent magnetic properties or by functionalization with bioactive or therapeutic compounds, such as drugs, enzymes and growth factors. In addition, the presence of magnetic fields can direct IONP-labeled cells specifically to the site of action or induce cell differentiation into a specific cell type through mechanotransduction.

Downregulation of augmenter of liver regeneration impairs the therapeutic efficacy of liver epithelial progenitor cells against acute liver injury by enhancing mitochondrial fission

Cell-based therapeutic approaches have been proven to be effective strategies for the treatment of acute liver injury (ALI). However, widespread application of these procedures is limited by several key issues, including rapid loss of stemness in vitro, aberrant differentiation into undesirable cell types, and low engraftment in vivo. In this study, liver epithelial progenitor cells (LEPCs) were characterized and transfected with augmenter of liver regeneration (ALR). The results revealed that in ALI mice with CCl₄ , the transplantation of ALR-bearing LEPCs into the liver markedly protected mice against ALI by decreasing the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), thus relieving hepatic tissue injury and attenuating inflammatory infiltration. Mechanistically, the knockdown of ALR in LEPCs activated the phosphorylation of dynamin-related protein 1 (Drp1) at the S616 site and thereby enhanced mitochondrial fission. In contrast, the transfection of ALR into LEPCs significantly inhibited Drp1 phosphorylation, thereby favoring the maintenance of mitochondrial integrity and the preservation of adenosine triphosphate contents in LEPCs. Consequently, the ALR-bearing LEPCs transplanted into ALI mice exhibited substantially greater homing ability to the injured liver via the SDF-1/CXCR4 axis than that of LEPCs-lacking ALR. In conclusion, we demonstrated that the transplantation of ALR-transfected LEPCs protected mice against CCl₄ -induced ALI, thus offering immense curative potential in the clinic.

Biodistribution of Mesenchymal Stromal Cells after Administration in Animal Models and Humans: A Systematic Review

Mesenchymal Stromal Cells (MSCs) are of great interest in cellular therapy. Different routes of administration of MSCs have been described both in pre-clinical and clinical reports. Knowledge about the fate of the administered cells is critical for developing MSC-based therapies. The aim of this review is to describe how MSCs are distributed after injection, using different administration routes in animal models and humans. A literature search was performed in order to consider how MSCs distribute after intravenous, intraarterial, intramuscular, intraarticular and intralesional injection into both animal models and humans. Studies addressing the biodistribution of MSCs in “in vivo” animal models and humans were included. After the search, 109 articles were included in the review. Intravenous administration of MSCs is widely used; it leads to an initial accumulation of cells in the lungs with later redistribution to the liver, spleen and kidneys. Intraarterial infusion bypasses the lungs, so MSCs distribute widely throughout the rest of the body. Intramuscular, intraarticular and intradermal administration lack systemic biodistribution. Injection into various specific organs is also described. Biodistribution of MSCs in animal models and humans appears to be similar and depends on the route of administration. More studies with standardized protocols of MSC administration could be useful in order to make results homogeneous and more comparable.

Optimal scanning concentration of MR imaging for tumor-bearing nude mice with SPIO-shRNA molecular probe

The objective of this study is to investigate the signal changes and optimal scanning concentration of MRI in tumor tissues of tumor-bearing nude mice by SPIO-shRNA molecular probes. 30 BALB/c tumor-bearing nude mice were randomly divided into 5 groups with 6 mice in each group. At the given scanning time (before and 27 h after injection), the caudal vein was respectively injected with iron content of 6 mg·kg-1, 12 mg·kg-1, 18 mg·kg-1, 24 mg·kg-1, and 30 mg·kg-1, and MR examination was simultaneously performed to measure signal intensity changes of tumor tissue and contralateral muscle tissue in each concentration group. After each examination above, the nude mice were sacrificed immediately, and the tumor and muscle tissues were removed for HE and Prussian blue staining,and observed under light microscope. Nude mice in 6 mg, 12 mg and 18 mg groups all survived after probe injection, but some nude mice died in 24 mg and 30 mg groups after probe injection or during scanning. The signal changes of T2WI and T2*WI sequences were the most obvious in MR scanning sequences. Compared with other groups, the signal intensity of the tumor tissue in 18 mg, 24 mg and 30 mg groups were most obvious (P < 0.05), while the 18 mg, 24 mg and 30 mg groups reached no statistical difference (P > 0.05 ); HE staining indicated that structural disorder of tumor tissue as well as increase of nuclear atypia. Prussian Blue staining showed that blue-stained iron particles were present in each experimental group,and the most densely distributed were in 18 mg,24 mg and 30 mg groups. Tumor tissue could be well labeled with SPIO-shRNA molecular probes, and the optimal MR scanning concentration (iron content) is 18 mg·kg-1.

Multifunctional nanoparticles in stem cell therapy for cellular treating of kidney and liver diseases

The review gives an overview of the mechanisms of internalization and distribution of nanoparticles in stem cells this is achieved via providing analysis of the methods used in exploring the migration routes of stem cells, and their reciprocity. In addition, exploring microenvironment target in the body, and tracking the fate of exogenously transplanted stem cells by using innovative and non-invasive techniques will also be discussed. Such techniques like magnetic resonance imaging (MRI), multimodality tracking, optical imaging, and nuclear medicine imaging, which were designed to follow up stem cell migration. This review will explain the various distinctive strategies to enhance homing of labeled stem cells with nanoparticles into damaged hepatic and renal tissues, this purpose was obtained by inducing a specific gene into stem cells, various chemokines, and applying an external magnetic field. Also, this work illustrates how to improve nanoparticles uptake by using transfection agents or covalently binding an exogenous protein (i.e., Human immunodeficiency virus-Tat protein) or conjugating a receptor-specific monoclonal antibody or make modifications to iron coat. It contains stem cell labeling methods such as extracellular labeling and internalization approaches. Ultimately, our review indicates trails of researchers in nanoparticles utilization in stem cell therapy in both kidney and liver diseases.

Uptake and distribution of carboxylated quantum dots in human mesenchymal stem cells: cell growing density matters

BACKGROUND

Human mesenchymal stem cells (MSCs) have drawn much attention in the field of regenerative medicine for their immunomodulatory and anti-inflammatory effects. MSCs possess specific tumor-oriented migration and incorporation highlighting the potential for MSCs to be used as an ideal carrier for anticancer agents. Bone marrow is the main source of MSCs for clinical applications. MSCs tracking in vivo is a critical component of the safety and efficacy evaluation of therapeutic cell products; therefore, cells must be labeled with contrast agents to enable visualization of the MSCs migration in vivo. Due to their unique properties, quantum dots (QDs) are emerging as optimal tools in long-term MSC optical imaging applications. The aim of this study was to investigate the uptake dynamics, cytotoxity, subcellular and extracellular distribution of non-targeted carboxylated quantum dots in human bone marrow MSCs at different cell growing densities.

RESULTS

QDs had no negative impact on MSC viability throughout the experiment and accumulated in all observed cells efficiently; however, in some MSCs QDs induced formation of lipid droplets. At low cell growing densities QDs distribute within MSCs cytoplasm already after 1 h of incubation reaching saturation after 6 h. After 24 h QDs localize mainly in the perinuclear region of the cells in endosomes. Interestingly, in more confluent culture QDs localize mostly outside MSCs. QDs abundantly mark MSC long filopodia-like structures attaching neighboring cells. At high cell density cultivation, we for the first time demonstrated that carboxylated QDs localize in human bone marrow MSC extracellular matrix. Moreover, we observed that average photoluminescence lifetime of QDs distributed in extracellular matrix are longer than lifetimes of QDs entrapped in endocytic vesicles; thus, for the first time showing the possibility to identify and distinguish localization of QDs in various extracellular and intracellular structures using fluorescence-lifetime imaging microscopy without additional staining assays.

CONCLUSION

Carboxylated QDs can be used as nonspecific and effective dye for staining of human bone marrow MSCs and their specific extracellular structures. These results are promising in fundamental stem cell biology as well as in cellular therapy, anticancer drug delivery and tissue engineering.

Noninvasive Tracking and Regenerative Capabilities of Transplanted Human Umbilical Cord-Derived Mesenchymal Stem Cells Labeled with I-III-IV Semiconducting Nanocrystals in Liver-Injured Living Mice

Acute liver injury is a critical syndrome ascribed to prevalent death of hepatocytes and imperatively requires liver transplantation. Such a methodology is certainly hampered due to the deficit of healthy donors. In this regard, stem cell-based regenerative therapies are attractive in repairing injured tissues and organs for medical applications. However, it is crucial to understand the migration, engraftment, and regeneration capabilities of transplanted stem cells in the living animal models. For the first time, we demonstrate rapid labeling of umbilical cord-derived mesenchymal stem cells (MSCs) with near-infrared (NIR)-fluorescent CuInS₂-ZnS nanocrystals (CIZS-NCs) to develop innovative nanobioconjugates (MSCs-CIZS-NBCs) that exhibit 98% labeling efficiency. Before nanobioconjugate synthesis, the pristine CIZS-NCs were prepared via a two-step, hot-injection, rapid and low-cost domestic-microwave-refluxing (MW-R) method within 6 min. The as-synthesized CIZS-NCs display high photoluminescence quantum yield (∼88%) and long-lived lifetime (23.4 μs). In contrast to unlabeled MSCs, the MSCs-CIZS nanobioconjugates show excellent biocompatibility without affecting the stemness, as confirmed by cell viability, immunophenotyping (CD44⁺, CD105⁺, CD90⁺), multi-lineage-specific gene expressions, and differentiation into adipocytes, osteocytes, and chondrocytes. The in vivo fluorescence tracking analyses revealed that the MSCs-CIZS-NBCs after tail-vein injection were initially trapped in the lungs and gradually engrafted in the injured liver within 2 h. The regeneration potential of MSCs-CIZS-NBCs was confirmed via renewal of the portal tract composed of portal veins, bile ducts, and hepatic arteries around the hepatocytes. Consequently, no apparent inflammations, necrosis, or apoptosis was observed in the acetaminophen (APAP)-induced liver-injured BALB/c mice model over 3 days after transplantation, as corroborated using laser-scanning confocal microscopy and histopathological and hematological analyses. Hence, our innovative NIR-fluorescent MSCs-CIZS-NBCs offer an off-the-self technology for noninvasive tracking of transplanted MSCs in an acute-liver-injured animal model for future image-guided cell-therapies.

Preclinical imaging methods for assessing the safety and efficacy of regenerative medicine therapies

Regenerative medicine therapies hold enormous potential for a variety of currently incurable conditions with high unmet clinical need. Most progress in this field to date has been achieved with cell-based regenerative medicine therapies, with over a thousand clinical trials performed up to 2015. However, lack of adequate safety and efficacy data is currently limiting wider uptake of these therapies. To facilitate clinical translation, non-invasive in vivo imaging technologies that enable careful evaluation and characterisation of the administered cells and their effects on host tissues are critically required to evaluate their safety and efficacy in relevant preclinical models. This article reviews the most common imaging technologies available and how they can be applied to regenerative medicine research. We cover details of how each technology works, which cell labels are most appropriate for different applications, and the value of multi-modal imaging approaches to gain a comprehensive understanding of the responses to cell therapy in vivo.

Monitoring/Imaging and Regenerative Agents for Enhancing Tissue Engineering Characterization and Therapies

The past three decades have seen numerous advances in tissue engineering and regenerative medicine (TERM) therapies. However, despite the successes there is still much to be done before TERM therapies become commonplace in clinic. One of the main obstacles is the lack of knowledge regarding complex tissue engineering processes. Imaging strategies, in conjunction with exogenous contrast agents, can aid in this endeavor by assessing in vivo therapeutic progress. The ability to uncover real-time treatment progress will help shed light on the complex tissue engineering processes and lead to development of improved, adaptive treatments. More importantly, the utilized exogenous contrast agents can double as therapeutic agents. Proper use of these Monitoring/Imaging and Regenerative Agents (MIRAs) can help increase TERM therapy successes and allow for clinical translation. While other fields have exploited similar particles for combining diagnostics and therapy, MIRA research is still in its beginning stages with much of the current research being focused on imaging or therapeutic applications, separately. Advancing MIRA research will have numerous impacts on achieving clinical translations of TERM therapies. Therefore, it is our goal to highlight current MIRA progress and suggest future research that can lead to effective TERM treatments.

Nanotechnology for mesenchymal stem cell therapies

Mesenchymal stem cells (MSC) display great proliferative, differentiative, chemotactic, and immune-modulatory properties required to promote tissue repair. Several clinical trials based on the use of MSC are currently underway for therapeutic purposes. The aim of this article is to examine the current trends and potential impact of nanotechnology in MSC-driven regenerative medicine. Nanoparticle-based approaches are used as powerful carrier systems for the targeted delivery of bioactive molecules to ensure MSC long-term maintenance in vitro and to enhance their regenerative potential. Nanostructured materials have been developed to recapitulate the stem cell niche within a tissue and to instruct MSC toward the creation of regeneration-permissive environment. Finally, the capability of MSC to migrate toward the site of injury/inflammation has allowed for the development of diagnostic imaging systems able to monitor transplanted stem cell bio-distribution, toxicity, and therapeutic effectiveness.

Stromal cell-derived factor 1 promoted migration of adipose-derived stem cells to the wounded area in traumatic rats

BACKGROUND

Adipose-derived stem cells (ADSCs) were effective in treating wound. Stromal cell-derived factor-1 (SDF-1), a chemokine usually called CXCL12, is well known for its chemotaxis in induction of cell migration. However, little is known about the SDF-1responsible for the complex migration of ADSCs from residence to injured sites.

OBJECTIVE

Herein, we firstly showed SDF-1 is a major regulator involved in migration of ADSCs during wound repair in vivo.

METHODS

Trauma in rats was induced by surgical operation. The levels of SDF-1 in wounded tissue were assayed by ELISA. ADSCs were labeled with Green Fluorescent Protein (GFP), and then were transferred to injured rats by intracarotid injection. The plasma levels of ADSCs during wound healing were detected by flow cytometry, and ADSCs in injured tissue were evaluated by bioluminescence imaging in vivo and laser confocal microscopy (LCM), respectively.

RESULTS

ADSCs were successfully labeled with GFP. SDF-1 level reached to the peak value on 24 h after injury and then decreased continuously. Additionally, levels of plasma ADSCs in SDF-1 treated rats reached to the peak value (12%) at d21 after medicine delivery, while those of normal and injured rats showed the peak values of 6.28% and 9.84% at d7 and d21, respectively. Finally, the results of LCM indicated treatment of ectogenic SDF-1 obviously enhanced GFP-ADSCs distribution in wounded tissues.

CONCLUSION

Our results indicated that SDF-1 treatment obviously promoted the migration and directed distribution of ADSCs in traumatic tissue.