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

Metabolic Nanoregulator Remodels Gut Microenvironment for Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is strongly related to the occurrence of accumulation of toxic reactive oxygen species (ROS), inflammation of the mucosa, and an imbalance of intestinal microbes. However, current treatments largely focus on a single factor, yielding unsatisfactory clinical outcomes. Herein, we report a biocompatible and IBD-targeted metabolic nanoregulator (TMNR) that synergistically regulates cellular and bacterial metabolism. The TMNR comprises a melanin-gallium complex (MNR) encapsulated within a thermosensitive and colitis-targeting hydrogel, all composed of natural and FDA-approved components. The TMNR confers superior broad-spectrum antioxidant properties, effectively scavenging reactive oxygen species (ROS) and blocking inflammatory signaling pathways. The presence of Ga3+ in TMNR selectively disrupts iron metabolism in pathogenic microorganisms due to its structural resemblance to the iron atom. Additionally, incorporating a thermosensitive injectable hydrogel enables targeted delivery of TMNR to inflammatory regions, prolonging their retention time and providing a physical barrier function for optimizing IBD treatment efficacy. Collectively, TMNR effectively modulates the redox balance of inflamed colonic epithelial tissue and disrupts iron metabolism in pathogenic microorganisms, thereby eliminating inflammation and restoring intestinal homeostasis against IBD. Hence, this work presents a comprehensive approach for precise spatiotemporal regulation of the intestinal microenvironmental metabolism for IBD treatment.

Nanocrystals for Deep-Tissue In Vivo Luminescence Imaging in the Near-Infrared Region

In vivo imaging technologies have emerged as a powerful tool for both fundamental research and clinical practice. In particular, luminescence imaging in the tissue-transparent near-infrared (NIR, 700-1700 nm) region offers tremendous potential for visualizing biological architectures and pathophysiological events in living subjects with deep tissue penetration and high imaging contrast owing to the reduced light-tissue interactions of absorption, scattering, and autofluorescence. The distinctive quantum effects of nanocrystals have been harnessed to achieve exceptional photophysical properties, establishing them as a promising category of luminescent probes. In this comprehensive review, the interactions between light and biological tissues, as well as the advantages of NIR light for in vivo luminescence imaging, are initially elaborated. Subsequently, we focus on achieving deep tissue penetration and improved imaging contrast by optimizing the performance of nanocrystal fluorophores. The ingenious design strategies of NIR nanocrystal probes are discussed, along with their respective biomedical applications in versatile in vivo luminescence imaging modalities. Finally, thought-provoking reflections on the challenges and prospects for future clinical translation of nanocrystal-based in vivo luminescence imaging in the NIR region are wisely provided.

Fluorescence-Based Mono- and Multimodal Imaging for In Vivo Tracking of Mesenchymal Stem Cells

The advancement of stem cell therapy has offered transformative therapeutic outcomes for a wide array of diseases over the past decades. Consequently, stem cell tracking has become significant in revealing the mechanisms of action and ensuring safe and effective treatments. Fluorescence stands out as a promising choice for stem cell tracking due to its myriad advantages, including high resolution, real-time monitoring, and multi-fluorescence detection. Furthermore, combining fluorescence with other tracking modalities-such as bioluminescence imaging (BLI), positron emission tomography (PET), photoacoustic (PA), computed tomography (CT), and magnetic resonance (MR)-can address the limitations of single fluorescence detection. This review initially introduces stem cell tracking using fluorescence imaging, detailing various labeling strategies such as green fluorescence protein (GFP) tagging, fluorescence dye labeling, and nanoparticle uptake. Subsequently, we present several combinations of strategies for efficient and precise detection.

Melanin/melanin-like nanoparticles: As a naturally active platform for imaging-guided disease therapy

The development of biocompatible and efficient nanoplatforms that combine diagnostic and therapeutic functions is of great importance for precise disease treatment. Melanin, an endogenous biopolymer present in living organisms, has attracted increasing attention as a versatile bioinspired functional platform owing to its unique physicochemical properties (e.g., high biocompatibility, strong chelation of metal ions, broadband light absorption, high drug binding properties) and inherent antioxidant, photoprotective, anti-inflammatory, and anti-tumor effects. In this review, the fundamental physicochemical properties and preparation methods of natural melanin and melanin-like nanoparticles were outlined. A systematical description of the recent progress of melanin and melanin-like nanoparticles in single, dual-, and tri-multimodal imaging-guided the visual administration and treatment of osteoarthritis, acute liver injury, acute kidney injury, acute lung injury, brain injury, periodontitis, iron overload, etc. Was then given. Finally, it concluded with a reasoned discussion of current challenges toward clinical translation and future striving directions. Therefore, this comprehensive review provides insight into the current status of melanin and melanin-like nanoparticles research and is expected to optimize the design of novel melanin-based therapeutic platforms and further clinical translation.

Multiple Dimensions of using Mesenchymal Stem Cells for Treating Liver Diseases: From Bench to Beside

Liver diseases impose a huge burden worldwide. Although hepatocyte transplantation has long been considered as a potential strategy for treating liver diseases, its clinical implementation has created some obvious limitations. As an alternative strategy, cell therapy, particularly mesenchymal stem cell (MSC) transplantation, is widely used in treating different liver diseases, including acute liver disease, acute-on-chronic liver failure, hepatitis B/C virus, autoimmune hepatitis, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. Here, we summarize the status of MSC transplantation in treating liver diseases, focusing on the therapeutic mechanisms, including differentiation into hepatocyte-like cells, immunomodulating function with a variety of immune cells, paracrine effects via the secretion of various cytokines and extracellular vesicles, and facilitation of homing and engraftment. Some improved perspectives and current challenges are also addressed. In summary, MSCs have great potential in the treatment of liver diseases based on their multi-faceted characteristics, and more accurate mechanisms and novel therapeutic strategies stemming from MSCs will facilitate clinical practice.

In Vivo Fate of CXCR2-Overexpressing Mesenchymal Stromal/Stem Cells in Pulmonary Diseases Monitored by Near-Infrared Region 2 Imaging

Lung-associated diseases pose a huge threat to human society. Mesenchymal stromal/stem cells (MSCs) hold great promise in the treatment of pulmonary diseases through cell transdifferentiation, paracrine factors, immune regulation, EV secretion, and drug loading. However, intravenous injection of MSCs often resulted in limited lesion tropism and apparent off-target accumulation. The IL-8-CXCR1/2 chemokine axis has been shown to be involved in progression of diseases including lung cancer and acute lung injury (ALI). Herein, we took advantage of this chemokine axis to enhance the homing of MSCs to cancerous and inflammation lesions. The in vivo distribution of MSCs was further monitored real-time by near-infrared region 2 (NIR-II) imaging owing to its outstanding performance in deep tissue imaging. Specifically, a new high-brightness D-A-D NIR-II dye, LJ-858, was synthesized and coprecipitated with a poly(d,l-lactic acid) polymer to form LJ-858 nanoparticles (NPs) with a relative quantum yield of 14.978%. LJ-858 NPs can efficiently label MSCs, and the NIR-II signal can be stable for 14 days without compromising the cell viability. Subcutaneous tracking of labeled MSCs showed no significant decline of NIR-II intensity within 24 h. The enhanced tropism of CXCR2-overexpressing MSCs to A549 tumor cells and the inflamed lung tissue was demonstrated through transwell models. The in vivo and ex vivo NIR-II imaging results further validated the significantly enhanced lesion retention of MSC^CXCR2 in the lung cancer and ALI models. Taken together, this work reported a robust strategy to enhance the pulmonary disease tropism by the IL-8-CXCR1/2 chemokine axis. In addition, in vivo distribution of MSCs was successfully visualized by NIR-II imaging, which provides more insights into optimizing protocols for MSC-based therapies in the future.

Dual-modality and Noninvasive Diagnostic of MNP-PEG-Mn Nanoprobe for Renal Fibrosis Based on Photoacoustic and Magnetic Resonance Imaging

To date, imaging-guided multimodality therapy is important to improve the accuracy of the diagnosis of renal fibrosis, and nanoplatforms for imaging-guided multimodality diagnosis are gaining more and more attention. There are many limitations and deficiencies in clinical use for early-stage diagnosis of renal fibrosis, and multimodal imaging can contribute more thoroughly and provide in-detail information for effective clinical diagnosis. Melanin is an endogenous biomaterial, and we developed an ultrasmall particle size melanin nanoprobe (MNP-PEG-Mn) based on photoacoustic (PA) and magnetic resonance (MR) dual-modal imaging. MNP-PEG-Mn nanoprobe, with the average diameter about 2.7 nm, can be passively targeted for accumulation in the kidney, and it has excellent free radical scavenging and antioxidant abilities without further exacerbating renal fibrosis. Using the normal group signal as a control, the dual-modal imaging results showed that the MR imaging (MAI) and PA imaging (PAI) signals reached the strongest at 6 h when MNP-PEG-Mn entered the 7 day renal fibrosis group via the left vein of the tail end of the mice; however, the strength of the dual-modal imaging signal and the gradient of signal change were significantly weaker in the 28 day renal fibrosis group than in the 7 day renal fibrosis group and normal group. The phenomenon preliminarily indicates that as a PAI/MRI dual-modality contrast medium candidate, MNP-PEG-Mn has outstanding ability in clinical application potential.

Dual-modal molecular imaging and therapeutic evaluation of coronary microvascular dysfunction using indocyanine green-doped targeted microbubbles

Coronary microvascular dysfunction (CMD), which causes a series of cardiovascular diseases, seriously endangers human health. However, precision diagnosis of CMD is still challenging due to the lack of sensitive probes and complementary imaging technologies. Herein, we demonstrate indocyanine green-doped targeted microbubbles (named T-MBs-ICG) as dual-modal probes for highly sensitive near-infrared (NIR) fluorescence imaging and high-resolution ultrasound imaging of CMD in mouse models. In vitro results show that T-MBs-ICG can specifically target fibrin, a specific CMD biomarker, via the cysteine-arginine-glutamate-lysine-alanine (CREKA) peptide modified on the surface of microbubbles. We further employ T-MBs-ICG to achieve NIR fluorescence imaging of injured myocardial tissue in a CMD mouse model, leading to a signal-to-background ratio (SBR) of up to 50, which is 20 fold higher than that of the non-targeted group. Furthermore, ultrasound molecular imaging of T-MBs-ICG is obtained within 60 s after intravenous injection, providing molecular information on ventricular and myocardial structures and fibrin with a resolution of 1.033 mm × 0.466 mm. More importantly, we utilize comprehensive dual-modal imaging of T-MBs-ICG to evaluate the therapeutic efficacy of rosuvastatin, a cardiovascular drug for the clinical treatment of CMD. Overall, the developed T-MBs-ICG probes with good biocompatibility exhibit great potential in the clinical diagnosis of CMD.

State-of-the-Art and Future Directions in Organ Regeneration with Mesenchymal Stem Cells and Derived Products during Dynamic Liver Preservation

Transplantation is currently the treatment of choice for end-stage liver diseases but is burdened by the shortage of donor organs. Livers from so-called extended-criteria donors represent a valid option to overcome organ shortage, but they are at risk for severe post-operative complications, especially when preserved with conventional static cold storage. Machine perfusion technology reduces ischemia-reperfusion injury and allows viability assessment of these organs, limiting their discard rate and improving short- and long-term outcomes after transplantation. Moreover, by keeping the graft metabolically active, the normothermic preservation technique guarantees a unique platform to administer regenerative therapies ex vivo. With their anti-inflammatory and immunomodulatory properties, mesenchymal stem cells are among the most promising sources of therapies for acute and chronic liver failure, but their routine clinical application is limited by several biosafety concerns. It is emerging that dynamic preservation and stem cell therapy may supplement each other if combined, as machine perfusion can be used to deliver stem cells to highly injured grafts, avoiding potential systemic side effects. The aim of this narrative review is to provide a comprehensive overview on liver preservation techniques and mesenchymal stem cell-based therapies, focusing on their application in liver graft reconditioning.

Multimodal molecular imaging in the second near-infrared window

Near-infrared-II (NIR-II) fluorescence imaging has rapidly developed for the noninvasive investigation of physiological and pathological activities in living organisms with high spatiotemporal resolution. However, the penetration depth of fluorescence restricts its ability to provide deep anatomical information. Scientists integrate NIR-II fluorescence imaging with other imaging modes (such as photoacoustic and magnetic resonance imaging) to create multimodal imaging that can acquire detailed anatomical and quantitative information with deeper penetration by using multifunctional probes. This review offers a comprehensive picture of NIR-II-based dual/multimodal imaging probes and highlights advances in bioimaging and therapy. In addition, seminal studies and trends in multimodal imaging probes activated by NIR-II laser are summarized and several key points regarding future clinical translation are elucidated.

The Advances and Biomedical Applications of Imageable Nanomaterials

Nanomedicine shows great potential in screening, diagnosing and treating diseases. However, given the limitations of current technology, detection of some smaller lesions and drugs’ dynamic monitoring still need to be improved. With the advancement of nanotechnology, researchers have produced various nanomaterials with imaging capabilities which have shown great potential in biomedical research. Here, we summarized the researches based on the characteristics of imageable nanomaterials, highlighted the advantages and biomedical applications of imageable nanomaterials in the diagnosis and treatment of diseases, and discussed current challenges and prospects.

An auto-photoacoustic melanin-based drug delivery nano-platform for self-monitoring of acute kidney injury therapy via a triple-collaborative strategy

Rhabdomyolysis-induced acute kidney injury (AKI) is closely related to toxic reactive oxygen species (ROS), apoptosis, and inflammation. Excessive activation of poly (ADP-ribose) polymerase-l (PARP-1) by ROS can cause mitochondrial dysfunction and release of the proapoptotic protein AIF, which triggers an intrinsic PARP-1-dependent cell death program. Considering these characteristics of rhabdomyolysis-induced AKI, we developed a targeting nanodrug delivery platform by loading PJ34 and coupling anti-GPR97 with melanin nanoparticles (GMP nanoparticles) that could realize photoacoustic self-monitoring and triple-collaborative treatment (antioxidant, antiapoptotic, and anti-inflammatory). The nanoparticles exhibited good dispersibility, solubility, and broad-spectrum ROS scavenging ability. In vitro experiments revealed high biocompatibility of the GMP nanoparticles and strong ability of scavenging multiple toxic ROS, antiapoptotic activity, and anti-inflammatory activity. Because melanin nanoparticles possess inherent photoacoustic (PA) imaging capability, they can not only serve as a drug carrier but also perform self-monitoring for real-time tracking of GMP biodistribution and renal uptake in a murine AKI model through PA imaging. In vivo experiments showed that the GMP nanoparticles could effectively reduce oxidative stress, apoptosis, and inflammatory response in mice with rhabdomyolysis-induced AKI, and the mechanism of alleviation was verified through western blot experiments. These results indicated that the nanoplatform could realize the targeted delivery and curative effect monitoring under the guidance of PA imaging, which is of great significance for the prevention and treatment of AKI. STATEMENT OF SIGNIFICANCE: : A targeting nanodrug delivery platform was developed by loading PJ34 and coupling anti-GPR97 with melanin nanoparticles (GMP nanoparticles) for photoacoustic self-monitoring and triple-collaborative treatment (antioxidant, antiapoptotic, and anti-inflammatory) of acute kidney injury (AKI). Further studies indicated that the Keap-1/Nrf2/HO-1 and PARP-1/AIF signaling pathways are involved in the therapeutic mechanisms to alleviate AKI. Immunohistochemical staining and routine blood test confirmed the anti-inflammatory performance of GMP nanoparticles. Compared to exogenous nanomaterials, we used endogenous melanin with broad ROS scavenging capacity as the nanocarrier and antioxidant, which not only overcomes the defects of high specificity, potential toxicity, low loading capacity, and high cost but also shows good biosafety and photoacoustic imaging performance in vivo.

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.

Exosomal microRNA-140-3p from human umbilical cord mesenchymal stem cells attenuates joint injury of rats with rheumatoid arthritis by silencing SGK1

OBJECTIVE

Over the years, microRNAs (miRNAs) have been involved in the pathogenesis of rheumatoid arthritis (RA). We aim to investigate the role of human umbilical cord mesenchymal stem cells (HUCMSCs)-derived exosomal miR-140-3p in RA development.

METHODS

Exosomes(exo) were isolated from human umbilical cord-derived mesenchymal stem cells (HUCMSCs), and this isolation was followed by the transfer of miR-140-3p. RA rat models were constructed by collagen II adjuvant and respectively treated with HUCMSCs-exo or HUCMSCs-exo carrying miR-140-3p mimic/inhibitor, and expression of miR-140-3p and serum- and glucocorticoid-inducible kinase 1 (SGK1) was assessed. Then, RA score and inflammation scoring, fibrosis degree and apoptosis, serum inflammatory response and oxidative stress in joint tissues were determined. The RA synovial fibroblasts (RASFs) were extracted from rats and identified. Conducted with relative treatment, the migration, proliferation and apoptosis in RASFs were determined.

RESULTS

MiR-140-3p was decreased while SGK1 was increased in RA rats. HUCMSCs-exo or upregulated exosomal miR-140-3p improved pathological changes and suppressed inflammation, oxidative stress and fibrosis in RA rats, and also constrained and RASF growth. Overexpression of SGK1 reversed the inhibition of RASF growth caused by overexpression of miR-140-3p.

CONCLUSION

Upregulated exosomal miR-140-3p attenuated joint injury of RA rats by silencing SGK1. This research provided further understanding of the role of exosomal miR-140-3p in RA development.

Multimodal Imaging-Guided Spatiotemporal Tracking of Photosensitive Stem Cells for Breast Cancer Treatment

Stem cell therapy has shown great potential in treating a wide range of diseases including cancer. The real-time tracking of stem cells with high spatiotemporal resolution and stable imaging signals remains the bottleneck to evaluate and monitor therapeutic outcomes once transplanted into patients. Here, we developed a photosensitive mesenchymal stem cell (MSC) loaded with mesoporous silica-coated gold nanostars (MGNSs) integrated with indocyanine green for spatiotemporal tracking and imaging-guided photothermal therapy (PTT) in treating breast cancers. The MGNS served as a stable imaging probe with multifunctional properties for photoacoustic imaging (PAI), fluorescence imaging, and PT imaging. Owing to the excellent PT stability of MGNSs, long-term three-dimensional (3D) PAI was achieved to monitor stem cells in real time at the tumor site, while the tumor structure was imaged using 3D B-mode ultrasound imaging. PAI revealed that the photosensitive stem cells reached the widest distribution area at the tumor site post 24 h of intratumoral injection, which was further confirmed via two-dimensional (2D) PT and fluorescence imaging. With this optimal cell distribution window, in vivo studies showed that the photosensitive stem cells via both intratumoral and intravenous injections successfully inhibited breast cancer cell growth and decreased the tumor recurrence rate post PTT. Our results support that this photo-integrated platform with stable optical properties is promising to achieve real-time tracking and measure the cell distribution quantitatively with high spatiotemporal resolution for stem cell therapy.

Melanin nanoparticles enhance the neuroprotection of mesenchymal stem cells against hypoxic-ischemic injury by inhibiting apoptosis and upregulating antioxidant defense

Polydopamine nanoparticles are artificial melanin nanoparticles (MNPs) that show strong antioxidant activity. The effects of MNPs on the neuroprotection of mesenchymal stem cells (MSCs) against hypoxic-ischemic injury and the underlying mechanism have not yet been revealed. In this study, an oxygen-glucose deprivation (OGD)-injured neuron model was used to mimic neuronal hypoxic-ischemic injury in vitro. MSCs pretreated with MNPs and then cocultured with OGD-injured neurons were used to investigate the potential effects of MNPs on the neuroprotection of MSCs and to elucidate the underlying mechanism. After coculturing with MNPs-pretreated MSCs, MSCs, and MNPs in a transwell coculture system, the OGD-injured neurons were rescued by 91.24%, 79.32% and 59.97%, respectively. Further data demonstrated that MNPs enhanced the neuroprotection against hypoxic-ischemic injury of MSCs by scavenging reactive oxygen species (ROS) and superoxide and attenuating neuronal apoptosis by deactivating caspase-3, downregulating the expression of proapoptotic Bax proteins and upregulating the expression of antiapoptotic Bcl-2 proteins. These findings suggest that MNPs enhance the neuroprotective effect of MSCs against hypoxic-ischemic injury by inhibiting apoptosis and upregulating antioxidant defense, which could provide some evidence for the potential application of combined MNPs and MSCs in the therapy for ischemic stroke. This article is protected by copyright. All rights reserved.

NIR-II Functional Materials for Photoacoustic Theranostics

Photoacoustic imaging (PAI) has attracted great attention in the diagnosis and treatment of diseases due to its noninvasive properties. Especially in the second near-infrared (NIR-II) window, PAI can effectively avoid the interference of tissue spontaneous fluorescence and light scattering, and obtain high resolution images with deeper penetration depth. Because of its ideal spectral absorption and high conversion efficiency, NIR-II PA contrast agents overcome the absorption or emission of NIR-II light by endogenous biomolecules. In recent years, a series of NIR-II PA contrast agents have been developed to improve the performance of PAI in disease diagnosis and treatment. In this paper, the research progress of NIR-II PA contrast agents and their applications in biomedicine are reviewed. PA contrast agents are classified according to their composition, including inorganic contrast agents, organic contrast agents, and hybrid organic-inorganic contrast agents. The applications of NIR-II PA contrast agents in medical imaging are described, such as cancer imaging, inflammation detection, brain disease imaging, blood related disease imaging, and other biomedical application. Finally, the research prospects and breakthrough of NIR-II PA contrast agents are discussed.

Protective effect of Que Zui tea hot-water and aqueous ethanol extract against acetaminophen-induced liver injury in mice via inhibition of oxidative stress, inflammation, and apoptosis

The tender leaves and buds of Vaccinium dunalianum Wight have been traditionally processed as folk tea, known as Que Zui tea (QT), with a wide range of benefits to humans. In this study, Que Zui tea hot-water extract (QTW) and aqueous-ethanol extract (QTE) were tested for their effectiveness to alleviate acetaminophen (APAP)-induced liver damage. QTW and QTE significantly inhibited the alanine aminotransaminase, aspartate aminotransaminase, tumor necrosis factor-α, interleukin-6, and interleukin-1β levels in the serum. Both extracts also ameliorated pathological damage and inhibited oxidative stress in the liver of APAP-induced mice. In addition, QTW and QTE activated the nuclear erythroid related factor 2 signal pathway, and inhibited mitogen-activated protein kinase activation. QTW and QTE also suppressed hepatocyte apoptosis by improvement of Bcl-2/Bax and inhibition of caspase-3 and caspase-9 expression. The results demonstrated that QTW and QTE could effectively protect APAP hepatotoxicity, which might be attributed to their antioxidant, anti-inflammatory and anti-apoptosis activities.