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

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

Advances in 3D Bioprinting: Techniques, Applications, and Future Directions for Cardiac Tissue Engineering

Cardiovascular diseases are the leading cause of morbidity and mortality in the United States. Cardiac tissue engineering is a direction in regenerative medicine that aims to repair various heart defects with the long-term goal of artificially rebuilding a full-scale organ that matches its native structure and function. Three-dimensional (3D) bioprinting offers promising applications through its layer-by-layer biomaterial deposition using different techniques and bio-inks. In this review, we will introduce cardiac tissue engineering, 3D bioprinting processes, bioprinting techniques, bio-ink materials, areas of limitation, and the latest applications of this technology, alongside its future directions for further innovation.

Umbilical cord mesenchymal stromal cells-from bench to bedside

In recent years, mesenchymal stromal cells (MSCs) have generated a lot of attention due to their paracrine and immuno-modulatory properties. mesenchymal stromal cells derived from the umbilical cord (UC) are becoming increasingly recognized as having increased therapeutic potential when compared to mesenchymal stromal cells from other sources. The purpose of this review is to provide an overview of the various compartments of umbilical cord tissue from which mesenchymal stromal cells can be isolated, the differences and similarities with respect to their regenerative and immuno-modulatory properties, as well as the single cell transcriptomic profiles of in vitro expanded and freshly isolated umbilical cord-mesenchymal stromal cells. In addition, we discuss the therapeutic potential and biodistribution of umbilical cord-mesenchymal stromal cells following systemic administration while providing an overview of pre-clinical and clinical trials involving umbilical cord-mesenchymal stromal cells and their associated secretome and extracellular vesicles (EVs). The clinical applications of umbilical cord-mesenchymal stromal cells are also discussed, especially in relation to obstacles and potential solutions for their effective translation from bench to bedside.

Repair of the Urethral Mucosa Defect Model Using Adipose-Derived Stem Cell Sheets and Monitoring the Fate of Indocyanine Green-Labeled Sheets by Near Infrared-II

Treatment of urethral mucosa defects is a major challenge in urology. Synthetic materials or autologous mucosa does not provide satisfactory treatment options for long-term or large urethral mucosa defects. In response to this problem, we used autologous adipose-derived stem cells (ADSCs) to synthesize cell sheets in vitro for repairing urethral mucosa defect models. In order to monitor the localization and distribution of cell sheets in vivo, cells and sheets were labeled with indocyanine green (ICG) and the second near-infrared (NIR-II) fluorescence imaging was performed. ICG-based NIR-II imaging can successfully track ADSCs and sheets in vivo up to 8 W. Then, rabbit urethral mucosa defect models were repaired with ICG-ADSCs sheets. At 3 months after operation, retrograde urethrography showed that ADSC sheets could effectively repair urethral mucosa defect and restore urethral patency. Histological analysis showed that in ADSC sheet groups, continuous epithelial cells covered the urethra at the transplantation site, and a large number of vascular endothelial cells could also be seen. In the cell-free sheet group, there was no continuous epithelial cell coverage at the repair site of the urethra, and the expression of pro-inflammatory factor TNF-α was increased. It shows that the extracellular matrix alone without cells is not suitable for repairing urethral defects. Surviving ADSCs in the sheets may play a key role in the repair process. This study provides a new tracing method for tissue engineering to dynamically track grafts using an NIR-II imaging system. The ADSC sheets can effectively restore the structure and function of the urethra. It provides a new option for the repair of urethral mucosa defects.

Micro-/nano-fluidic devices and in vivo fluorescence imaging based on quantum dots for cytologic diagnosis

Semiconductor quantum dots (QDs) possess attractive merits over traditional organic dyes, such as tunable emission, narrow emission spectra and good resistance against optical bleaching, and play a vital role in biosensing and bioimaging for cytologic diagnoses. Microfluidic technology is a potentially useful strategy, as it provides a rapid platform for tracing of disease markers. In vivo fluorescence imaging (FI) based on QDs has become popular for the analysis of complex biological processes. We herein report the applications of multifunctional fluorescent QDs as sensitive probes for diagnoses on cancer medicine and stem cell therapy via microfluidic chips and in vivo imaging.

Amelioration of aflatoxin acute hepatitis rat model by bone marrow mesenchymal stem cells and their hepatogenic differentiation

Background and Aim:

Bone marrow-derived mesenchymal stem cells (BM-MSCs) transplantation and their hepatogenic differentiated cells (HDCs) can be applied for liver injury repair by tissue grafting. Regenerative potentiality in liver cirrhosis models was widely investigated; however, immunomodulation and anti-inflammation in acute hepatitis remain unexplored. This study aimed to explore the immunomodulatory and evaluate twice intravenous (IV) or intrahepatic (IH) administration of either BM-MSCs or middle-stage HDCs on aflatoxin (AF) acute hepatitis rat model.

Materials and Methods:

BM-MSCs viability, phenotypes, and proliferation were evaluated. Hepatogenic differentiation, albumin, and mmmmmmmm-fetoprotein gene expression were assessed. AF acute hepatitis was induced in rats using AFB1 supplementation. The transplantation of BM-MSCs or their HDCs was done either by IV or IH route. Hepatic ultrasound was performed after 3-weeks of therapy. Cytokines profile (tumor necrosis factor-α [TNF-α], interleukin [IL]-4, and IL-10) was assessed. Hepatic bio-indices, serum, and hepatic antioxidant activity were evaluated, besides examining liver histological sections.

Results:

Acute AFB1 showed a significant increase in TNF-α (p<0.01), liver enzyme activities (p<0.05), as well as decrease in IL-4, IL-10, and antioxidant enzyme activities (p<0.05). Cytokines profile was ameliorated in groups treated with IV and IH BM-MCs, showed a negative correlation between IL-4 and TNF-α (p<0.05), and a positive correlation between IL-10 upregulation and TNF-α (p<0.01). In IV HDCs treated group, positive correlations between IL-4 and IL-10 downregulation and TNF-α were observed. However, in IH HDCs group, a significant positive correlation between IL-4 and IL-10 upregulation and TNF-α, were recorded (p<0.05). In addition, IV BM-MSCs and IH HDCs treatments significantly increased antioxidant enzymes activity (p<0.05). IV and IH BM-MSCs significantly ameliorated liver transaminase levels, whereas IH HDCs significantly ameliorated alanine aminotransferase activity and nitric oxide concentration (p<0.05).

Conclusion:

The administration routes of BM-MSCs did not demonstrate any significant difference; however, the IH route of HDCs showed significant amelioration from the IV route. On the other hand, it showed noticeable anti-inflammatory and immunomodulatory improvements in aflatoxicosis rats. Therefore, it can be concluded that acute hepatitis can be treated by a noninvasive IV route without the expense of hepatogenic differentiation. Further research using clinical trials that address several problems regarding engraftment and potentiation are needed to determine the optimal manipulation strategy as well as to achieve better long term effects.

Mesenchymal Stem Cells and Their Small Extracellular Vesicles as Crucial Immunological Efficacy for Hepatic Diseases

Mesenchymal stem cell small extracellular vesicles (MSC-sEVs) are a priority for researchers because of their role in tissue regeneration. sEVs act as paracrine factors and carry various cargos, revealing the state of the parent cells and contributing to cell–cell communication during both physiological and pathological circumstances. Hepatic diseases are mainly characterized by inflammatory cell infiltration and hepatocyte necrosis and fibrosis, bringing the focus onto immune regulation and other regulatory mechanisms of MSCs/MSC-sEVs. Increasing evidence suggests that MSCs and their sEVs protect against acute and chronic liver injury by inducing macrophages (MΦ) to transform into the M2 subtype, accelerating regulatory T/B (Treg/Breg) cell activation and promoting immunosuppression. MSCs/MSC-sEVs also prevent the proliferation and differentiation of T cells, B cells, dendritic cells (DCs), and natural killer (NK) cells. This review summarizes the potential roles for MSCs/MSC-sEVs, including immunomodulation and tissue regeneration, in various liver diseases. There is also a specific focus on the use of MSC-sEVs for targeted drug delivery to treat hepatitis.

Mesenchymal Stem Cell Therapy for Acetaminophen-Related Liver Injury: A Systematic Review and Meta-Analysis of Experimental Studies in Vivo

OBJECTIVE

The efficacy of mesenchymal stem cell (MSC) therapy in acetaminophen-induced liver injury has been investigated in animal experiments, but individual studies with a small sample size cannot be used to draw a clear conclusion. Therefore, we conducted a systematic review and meta-analysis of preclinical studies to explore the potential of using MSCs in acetaminophen-induced liver injury.

METHODS

Eight databases were searched for studies reporting the effects of MSCs on acetaminophen hepatoxicity. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used. SYRCLE's risk of bias tool for animal studies was applied to assess the methodological quality. A meta-analysis was performed by using RevMan 5.4 and STATA/SE 16.0 software.

RESULTS

Eleven studies involving 159 animals were included according to PRISMA statement guidelines. Significant associations were found for MSCs with the levels of alanine transaminase (ALT) (standardized mean difference (SMD) - 2.58, p < 0.0001), aspartate aminotransferase (AST) (SMD - 1.75, p = 0.001), glutathione (GSH) (SMD 3.7, p < 0.0001), superoxide dismutase (SOD) (SMD 1.86, p = 0.022), interleukin 10 (IL-10) (SMD 5.14, p = 0.0002) and tumor necrosis factor-α (TNF-α) (SMD - 4.48, p = 0.011) compared with those in the control group. The subgroup analysis showed that the tissue source of MSCs significantly affected the therapeutic efficacy (p < 0.05).

CONCLUSION

Our meta-analysis results demonstrate that MSCs could be a potential treatment for acetaminophen-related liver injury.

Nanoparticles for Stem Cell Tracking and the Potential Treatment of Cardiovascular Diseases

Stem cell-based therapies have been shown potential in regenerative medicine. In these cells, mesenchymal stem cells (MSCs) have the ability of self-renewal and being differentiated into different types of cells, such as cardiovascular cells. Moreover, MSCs have low immunogenicity and immunomodulatory properties, and can protect the myocardium, which are ideal qualities for cardiovascular repair. Transplanting mesenchymal stem cells has demonstrated improved outcomes for treating cardiovascular diseases in preclinical trials. However, there still are some challenges, such as their low rate of migration to the ischemic myocardium, low tissue retention, and low survival rate after the transplantation. To solve these problems, an ideal method should be developed to precisely and quantitatively monitor the viability of the transplanted cells in vivo for providing the guidance of clinical translation. Cell imaging is an ideal method, but requires a suitable contrast agent to label and track the cells. This article reviews the uses of nanoparticles as contrast agents for tracking MSCs and the challenges of clinical use of MSCs in the potential treatment of cardiovascular diseases.

Mesenchymal Stem Cells in Gastric Cancer: Vicious but Hopeful

Tumor progression depends on the collaborative interactions between tumor cells and the surrounding stroma. First-line therapies direct against cancer cells may not reach a satisfactory outcome, such as gastric cancer (GC), with high risk of recurrence and metastasis. Therefore, novel treatments and drugs target the effects of stroma components are to be promising alternatives. Mesenchymal stem cells (MSC) represent the decisive components of tumor stroma that are found to strongly affect GC development and progression. MSC from bone marrow or adjacent normal tissues express homing profiles in timely response to GC-related inflammation signals and anchor into tumor bulks. Then the newly recruited “naïve” MSC would achieve phenotype and functional alternations and adopt the greater tumor-supporting potential under the reprogramming of GC cells. Conversely, both new-comers and tumor-resident MSC are able to modulate the tumor biology via aberrant activation of oncogenic signals, metabolic reprogramming and epithelial-to-mesenchymal transition. And they also engage in remodeling the stroma better suited for tumor progression through immunosuppression, pro-angiogenesis, as well as extracellular matrix reshaping. On the account of tumor tropism, MSC could be engineered to assist earlier diagnosis of GC and deliver tumor-killing agents precisely to the tumor microenvironment. Meanwhile, intercepting and abrogating vicious signals derived from MSC are of certain significance for the combat of GC. In this review, we mainly summarize current advances concerning the reciprocal metabolic interactions between MSC and GC and their underlying therapeutic implications in the future.

Enhanced and long-term CT imaging tracking of transplanted stem cells labeled with temperature-responsive gold nanoparticles

Gold nanoparticles (AuNPs) have been extensively employed for computed tomography (CT) imaging in cell labeling and tracking because of their strong X-ray attenuation coefficient and excellent biocompatibility. However, the design and synthesis of stimuli-responsive AuNPs to modulate their endocytosis and exocytosis for optimal cell labeling and tracking are promising but challenging. Herein, we report an innovative labeling strategy based on temperature-responsive AuNPs (TRAuNPs) with high cell labeling efficiency and extended intracellular retention duration. We have manifested that the TRAuNP labeling imposes a negligible adverse effect on the function of human mesenchymal stem cells (hMSCs). Further experiment with idiopathic pulmonary fibrosis (IPF) model mice has demonstrated the feasibility of TRAuNP labeling for long time CT imaging tracking of transplanted hMSCs. What's more, the survival of transplanted hMSCs could also be monitored simultaneously using bioluminescence imaging after the expression of luciferase reporter genes. Therefore, we believe that this dual-modal labeling and tracking strategy enables visualization of the transplanted hMSCs in vivo, which may provide an important insight into the role of stem cells in the IPF therapy.

Sandwich-Type Near-Infrared Conjugated Polymer Nanoparticles for Revealing the Fate of Transplanted Human Umbilical Cord Mesenchymal Stem Cells

Near-infrared conjugated polymer nanoparticles (NIR-CPNs) have been widely used in in vivo imaging fields. However, most of them face the aggregation-induced fluorescence quenching (ACQ) dilemma and serious dye leakage behavior, which impedes the long-term monitoring of transplanted cells in vivo. In the present work, a novel strategy of sandwich-type encapsulation of the conjugated polymer interlayer in the crystalline SiO2 core + shell (SSiO2@SPFTBT@CSiO2) is developed, which works well to avoid the ACQ problem by homogeneously dispersing poly((9,9-dioctylfluorene-2,7-diyl)-alt-(4,7-di(thiophene-2-yl)-2,1,3-benzothiadiazole)-5',5″-diyl) (PFTBT) and suppressing intermolecular π-π stacking. Furthermore, the unparalleled nanostructure efficiently stabilizes nanoparticles and successfully achieves long-term biocompatibility without interfering the biological characteristics of stem cells, indicating the potential of SSiO2@SPFTBT@CSiO2 in cell labeling. In addition, the fate of human umbilical cord mesenchymal stem cells (hucMSCs) in a mouse model with acute liver injury was disclosed. We found that the hucMSCs mainly migrated from the lungs to the injured liver and most transplanted hucMSCs were cleared up by the liver at 8 days post-injection. Revelation of the shuttle process and period will benefit in improving the clinical efficacy of hucMSCs, and the sandwich-type encapsulation strategy could also open a new avenue to obtain bright and robust NIR-CPNs for long-term fluorescence imaging.

Differential Responses of Transplanted Stem Cells to Diseased Environment Unveiled by a Molecular NIR-II Cell Tracker

Stem cell therapy holds high promises in regenerative medicine. The major challenge of clinical translation is to precisely and quantitatively evaluate the in vivo cell distribution, migration, and engraftment, which cannot be easily achieved by current techniques. To address this issue, for the first time, we have developed a molecular cell tracker with a strong fluorescence signal in the second near-infrared (NIR-II) window (1,000-1,700 nm) for real-time monitoring of in vivo cell behaviors in both healthy and diseased animal models. The NIR-II tracker (CelTrac1000) has shown complete cell labeling with low cytotoxicity and profound long-term tracking ability for 30 days in high spatiotemporal resolution for semiquantification of the biodistribution of transplanted stem cells. Taking advantage of the unique merits of CelTrac1000, the responses of transplanted stem cells to different diseased environments have been discriminated and unveiled. Furthermore, we also demonstrate CelTrac1000 as a universal and effective technique for ultrafast real-time tracking of the cellular migration and distribution in a 100 μm single-cell cluster spatial resolution, along with the lung contraction and heart beating. As such, this NIR-II tracker will shift the optical cell tracking into a single-cell cluster and millisecond temporal resolution for better evaluating and understanding stem cell therapy, affording optimal doses and efficacy.

NIR-II FL/PA dual-modal imaging long-term tracking of human umbilical cord-derived mesenchymal stem cells labeled with melanin nanoparticles and visible HUMSC-based liver regeneration for acute liver failure

Acetaminophen (APAP) has been widely used for relieving pain and fever, whilst overdose would lead to the occurrence of acute liver failure (ALF). Currently, few effective treatments are available for ALF in clinic, especially for severe, advanced- or end-stage patients who need liver transplantation. Human umbilical cord-derived mesenchymal stem cells (hUMSCs), as one of the mesenchymal stem cells, not only contribute to relieving hepatotoxicity and promoting hepatocyte regeneration due to their self-renewing, multi-differentiation potential, anti-inflammatory, immunomodulatory and paracrine properties, but possess lower immunomodulatory effects, faster self-renewal properties and noncontroversial ethical concerns, which may play a better role in the treatment of ALF. In this work, hUMSCs were rapidly labeled with near-infrared II fluorescent dye-modified melanin nanoparticles (MNP-PEG-H2), which could realize long-term tracking of hUMSCs by NIR-II fluorescent (FL)/photoacoustic (PA) dual-modal imaging and could visualize hUMSC-based liver regeneration in ALF. The nanoparticles exhibited good dispersibility and biocompatibility, high labeling efficiency for hUMSCs and excellent NIR-II FL/PA imaging performance. Moreover, the MNP-PEG-H2 labeled hUMSCs could be continuously traced in vivo for up to 21 days. After intravenous delivery, the NIR-II FL and PA images revealed that labeled hUMSCs were able to engraft in the injured liver and repair damaged tissue in ALF mice. Therefore, the hUMSCs labeled with endogenous melanin nanoparticles solve the key tracing problem of MSC-based regenerative medicine and realize the visualization of the treatment process, which may provide an efficient, safe and potential choice for ALF.

Differentiation of Cells Isolated from Afterbirth Tissues into Hepatocyte-Like Cells and Their Potential Clinical Application in Liver Regeneration

Toxic, viral and surgical injuries can pose medical indications for liver transplantation. The number of patients waiting for a liver transplant still increases, but the number of organ donors is insufficient. Hepatocyte transplantation was suggested as a promising alternative to liver transplantation, however, this method has some significant limitations. Currently, afterbirth tissues seem to be an interesting source of cells for the regenerative medicine, because of their unique biological and immunological properties. It has been proven in experimental animal models, that the native stem cells, and to a greater extent, hepatocyte-like cells derived from them and transplanted, can accelerate regenerative processes and restore organ functioning. The effective protocol for obtaining functional mature hepatocytes in vitro is still not defined, but some studies resulted in obtaining functionally active hepatocyte-like cells. In this review, we focused on human stem cells isolated from placenta and umbilical cord, as potent precursors of hepatocyte-like cells for regenerative medicine. We summarized the results of preclinical and clinical studies dealing with the introduction of epithelial and mesenchymal stem cells of the afterbirth origin to the liver failure therapy. It was concluded that the use of native afterbirth epithelial and mesenchymal cells in the treatment of liver failure could support liver function and regeneration. This effect would be enhanced by the use of hepatocyte-like cells obtained from placental and/or umbilical stem cells.

Microwave-Enhanced Chemistry at Solid-Liquid Interfaces: Synthesis of All-Inorganic CsPbX3 Nanocrystals and Unveiling the Anion-Induced Evolution of Structural and Optical Properties

We demonstrate how microwaves could enhance the chemistry at interfaces of heterogeneous reactions involved in the microwave-solvothermal (MW-ST) synthesis of all-inorganic CsPbX₃ (X = Cl, Br, I) perovskite nanocrystals (PNCs) within 6 min, unlike a conventional hot-injection method that requires 3 h. The enhanced MW-ST reaction rate was quantitatively analyzed by the Eyring equation, and it has been observed that the decreased activation free energy (ΔG^⧧) and increased activation entropy (ΔS^⧧) are caused by changes in the relative energies of reactants at their solid-liquid interfaces, leading to the formation of "hot spots", where microwave energy absorption is at its maximum. This rapid and homogeneous microwave heating could facilitate the self-assembly of uniformly distributed CsPbX₃ nanocubes with precise control over the stoichiometric ratio, as confirmed by high-resolution transmission electron microscopy and energy-dispersive X-ray analyses. X-ray diffraction and Raman results indicate that lattice contraction and expansion in CsPbBr_3-yX_y have occurred because of an increase in the metal-halide bond length upon moving down the groups Cl → Br → I, as further ascertained by the Rietveld refinement studies. These anion-induced structural variations accordingly affected the electronic properties of MW-ST-synthesized CsPbX₃ PNCs, which is apparent from the shifts in their conduction-band (CB) and valence-band (VB) positions. Consequently, the optical properties were also altered, resulting in a color-tuned emission from blue to red, with excellent photoluminescence quantum yields (up to 92%) and narrow emission line widths, as is evident from UV-vis and photoluminescence spectroscopy. The MW-ST-synthesized CsPbX₃ PNCs were used as color-conversion layers for the fabrication of light-emitting diodes (LEDs) with commercial 456 nm UV-LED chips.

Transplantation of mesenchymal stem cells and their derivatives effectively promotes liver regeneration to attenuate acetaminophen-induced liver injury

Acetaminophen (APAP)-induced injury is a common clinical phenomenon that not only occurs in a dose-dependent manner but also occurs in some idiosyncratic individuals in a dose-independent manner. APAP overdose generally results in acute liver injury via the initiation of oxidative stress, endoplasmic reticulum (ER) stress, autophagy, liver inflammation, and microcirculatory dysfunction. Liver transplantation is the only effective strategy for treating APAP-induced liver failure, but liver transplantation is inhibited by scarce availability of donor liver grafts, acute graft rejection, lifelong immunosuppression, and unbearable costs. Currently, N-acetylcysteine (NAC) effectively restores liver functions early after APAP intake, but it does not protect against APAP-induced injury at the late stage. An increasing number of animal studies have demonstrated that mesenchymal stem cells (MSCs) significantly attenuate acute liver injury through their migratory capacity, hepatogenic differentiation, immunoregulatory capacity, and paracrine effects in acute liver failure (ALF). In this review, we comprehensively discuss the mechanisms of APAP overdose-induced liver injury and current therapies for treating APAP-induced liver injury. We then comprehensively summarize recent studies about transplantation of MSC and MSC derivatives for treating APAP-induced liver injury. We firmly believe that MSCs and their derivatives will effectively promote liver regeneration and liver injury repair in APAP overdose-treated animals and patients. To this end, MSC-based therapies may serve as an effective strategy for patients who are waiting for liver transplantation during the early and late stages of APAP-induced ALF in the near future.

Human Umbilical Cord Wharton's Jelly-Derived Mesenchymal Stem Cells Labeled with Mn2+ and Gd3+ Co-Doped CuInS2-ZnS Nanocrystals for Multimodality Imaging in a Tumor Mice Model

Mesenchymal stem cell (MSCs) therapy has recently received profound interest as a targeting platform in cancer theranostics because of inherent tumor-homing abilities. However, the terminal tracking of MSCs engraftment by fluorescent in situ hybridization, immuno-histochemistry, and flow-cytometry techniques to translate into clinics is still challenging because of a dearth of inherent MSCs-specific markers and FDA approval for genetic modifications of MSCs. To address this challenge, a cost-effective noninvasive imaging technology based on multifunctional nanocrystals (NCs) with enhanced detection sensitivity, spatial-temporal resolution, and deep-tissue diagnosis is needed to be developed to track the transplanted stem cells. A hassle-free labeling of human umbilical cord Wharton's Jelly (WJ)-derived MSCs with Mn²⁺ and Gd³⁺ co-doped CuInS₂-ZnS (CIS-ZMGS) NCs has been demonstrated in 2 h without requiring an electroporation process or transfection agents. It has been found that WJ-MSCs labeling did not affect their multilineage differentiation (adipocyte, osteocyte, chondrocyte), immuno-phenotypes (CD44⁺, CD105⁺, CD90⁺), protein (β-actin, vimentin, CD73, α-SMCA), and gene expressions. Interestingly, CIS-ZMGS-NCs-labeled WJ-MSCs exhibit near-infrared (NIR) fluorescence with a quantum yield of 84%, radiant intensity of ∼3.999 × 10¹¹ (p/s/cm²/sr)/(μW/cm²), magnetic relaxivity (longitudinal r₁ = 2.26 mM^-1 s^-1, transverse r₂ = 16.47 mM^-1 s^-1), and X-ray attenuation (78 HU) potential for early noninvasive multimodality imaging of a subcutaneous melanoma in B16F10-tumor-bearing C57BL/6 mice in 6 h. The ex vivo imaging and inductively coupled plasma mass-spectroscopy analyses of excised organs along with confocal microscopy and immunofluorescence of tumor results also significantly confirmed the positive tropism of CIS-ZMGS-NCs-labeled WJ-MSCs in the tumor environment. Hence, we propose the magnetofluorescent CIS-ZMGS-NCs-labeled WJ-MSCs as a next-generation nanobioprobe of three commonly used imaging modalities for stem cell-assisted anticancer therapy and tracking tissue/organ regenerations.

Mesenchymal stem cells: Cell therapy and regeneration potential

Rapid advances in the isolation of multipotent progenitor cells, routinely called mesenchymal stromal/stem cells (MSCs), from various human tissues and organs have provided impetus to the field of cell therapy and regenerative medicine. The most widely studied sources of MSCs include bone marrow, adipose, muscle, peripheral blood, umbilical cord, placenta, fetal tissue, and amniotic fluid. According to the standard definition of MSCs, these clonal cells adhere to plastic, express cluster of differentiation (CD) markers such as CD73, CD90, and CD105 markers, and can differentiate into adipogenic, chondrogenic, and osteogenic lineages in vitro. However, isolated MSCs have been reported to vary in their potency and self-renewal potential. As a result, the MSCs used for clinical applications often lead to variable or even conflicting results. The lack of uniform characterization methods both in vitro and in vivo also contributes to this confusion. Therefore, the name "MSCs" itself has been increasingly questioned lately. As the use of MSCs is expanding rapidly, there is an increasing need to understand the potential sources and specific potencies of MSCs. This review discusses and compares the characteristics of MSCs and suggests that the variations in their distinctive features are dependent on the source and method of isolation as well as epigenetic changes during maintenance and growth. We also discuss the potential opportunities and challenges of MSC research with the hope to stimulate their use for therapeutic and regenerative medicine.

Cardiac tissue engineering: state-of-the-art methods and outlook

The purpose of this review is to assess the state-of-the-art fabrication methods, advances in genome editing, and the use of machine learning to shape the prospective growth in cardiac tissue engineering. Those interdisciplinary emerging innovations would move forward basic research in this field and their clinical applications. The long-entrenched challenges in this field could be addressed by novel 3-dimensional (3D) scaffold substrates for cardiomyocyte (CM) growth and maturation. Stem cell-based therapy through genome editing techniques can repair gene mutation, control better maturation of CMs or even reveal its molecular clock. Finally, machine learning and precision control for improvements of the construct fabrication process and optimization in tissue-specific clonal selections with an outlook of cardiac tissue engineering are also presented.