Locoregional delivery of stem cell-based therapies

Dental Pulp Stem Cells Attenuate Early Brain Injury After Subarachnoid Hemorrhage via miR-26a-5p/PTEN/AKT Pathway

Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke with high morbidity, mortality and disability, and early brain injury (EBI) after SAH is crucial for prognosis. Recently, stem cell therapy has garnered significant attention in the treatment of neurological diseases. Compared to other stem cells, dental pulp stem cells (DPSCs) possess several advantages, including abundant sources, absence of ethical concerns, non-invasive procurement, non-tumorigenic history and neuroprotective potential. Therefore, we aim to investigate whether DPSCs can improve EBI after SAH, and explore the mechanisms. In our study, we utilized the endovascular perforation method to establish a SAH mouse model and investigated whether DPSCs administered via tail vein injection could improve EBI after SAH. Furthermore, we used hemin-stimulated HT22 cells to simulate neuronal cell injury induced by SAH and employed a co-culture approach to examine the effects of DPSCs on these cells. To gain insights into the potential mechanisms underlying the improvement of SAH-induced EBI by DPSCs, we conducted bioinformatics analysis. Finally, we further validated our findings through experiments. In vivo experiments, we found that DPSCs administration improved neurological dysfunction, reduced brain edema, and prevented neuronal apoptosis in SAH mice. Additionally, we observed a decrease in the expression level of miR-26a-5p in the cortical tissues of SAH mice, which was significantly increased following intravenous injection of DPSCs. Through bioinformatic analysis and luciferase reporter assay, we confirmed the target relationship between miR-26a-5p and PTEN. Moreover, we demonstrated that DPSCs exerted neuroprotective effects by modulating the miR-26a-5p/PTEN/AKT pathway. Our study demonstrates that DPSCs can improve EBI after SAH through the miR-26a-5p/PTEN/AKT pathway, laying a foundation for the application of DPSCs in SAH treatment. These findings provide a theoretical basis for further investigating the therapeutic mechanisms of DPSCs and developing novel treatment strategies in SAH.

Trans-Vessel Wall Cell Transplantation, Engraftment, and Tumor Access in the VX2 Rabbit Model

The trans-vessel wall device (TW-device) is a new endovascular tool for precise and safe delivery of various payloads (cells, viral, modified RNA, chemotherapy, growth factors) in oncology and regenerative medicine. The twofold aim of this study was to assess cell engraftment and tumor growth using the TW-device for endovascular transplantation and to evaluate its ability to directly access solid tumors. We used the VX2 model in the rabbit kidney to compare percutaneously implanted fresh VX2 cells with TW-device injections of cryopreserved VX2 cells. We demonstrated the feasibility of endovascular transplantation (n = 7) of tumor cells, achieving a 57.1% engraftment rate despite cryopreservation, comparable with 70% for percutaneous delivery of fresh cells (n = 10). Re-access using the TW-device was 100% successful (n = 11) with super-selective intratumoral contrast administration without complications. In conclusion, endovascular transplantation of VX2 cells using the TW-device resulted in proliferating cell grafts in the rabbit kidney establishing functional proof that cells indeed survive handling, preparation, and device passage. We also show the TW-device is able to access solid tumor parenchyma allowing precise intraparenchymal administration.This proof-of-concept study open up possibilities for repeated direct parenchymal injections via the endovascular route in any hard to reach organ.

STL Inhibited Angiogenesis of DPSCs Through Depressing Mitochondrial Respiration by Enhancing RNF217

Angiogenesis is the determining factor during dental pulp regeneration. Six-twelve leukemia (STL) is identified as a key regulatory factor on the biological function of dental pulp stem cells (DPSCs) under hypoxic conditions, but its effect on angiogenesis is unclear. Co-culture of DPSCs and human umbilical vein endothelial cells (HUVECs) is used to detect tubule formation ability in vitro and the angiogenesis ability in vivo. RNA-seq and bioinformatic analyses are performed to screen differentially expressed genes. Seahorse Cell Mito Stress Test is proceeded to exam mitochondrial respiration. STL decreased tubule formation and mitochondrial respiration of DPSCs in vitro and restrained the number of blood vessels and the expression of VEGF in new formed tissue in vivo. Furthermore, pretreating STL-depleted DPSCs with rotenone, a mitochondrial respiration inhibitor, counteracted the promoting effect of STL knockdown on tubule formation. Then, RNA-seq and bioinformatic analyses identified some angiogenesis relevant genes and pathways in STL-depleted DPSCs. And STL enhanced expression of mRNA-ring finger protein 217 (RNF217), which inhibited the tubule formation and mitochondrial respiration of DPSCs. STL inhibited the angiogenesis of DPSCs through depressing mitochondrial respiration by enhancing RNF217, indicating that STL is a potential target for angiogenesis of DPSCs.

ROS-responsive hydrogels: from design and additive manufacturing to biomedical applications

Hydrogels with intricate 3D networks and high hydrophilicity have qualities resembling those of biological tissues, making them ideal candidates for use as smart biomedical materials. Reactive oxygen species (ROS) responsive hydrogels are an innovative class of smart hydrogels, and are cross-linked by ROS-responsive modules through covalent interactions, coordination interactions, or supramolecular interactions. Due to the introduction of ROS response modules, this class of hydrogels exhibits a sensitive response to the oxidative stress microenvironment existing in organisms. Simultaneously, due to the modularity of the ROS-responsive structure, ROS-responsive hydrogels can be manufactured on a large scale through additive manufacturing. This review will delve into the design, fabrication, and applications of ROS-responsive hydrogels. The main goal is to clarify the chemical principles that govern the response mechanism of these hydrogels, further providing new perspectives and methods for designing responsive hydrogel materials.

Stem cell therapies for neurological disorders: current progress, challenges, and future perspectives

Stem cell-based therapies have emerged as a promising approach for treating various neurological disorders by harnessing the regenerative potential of stem cells to restore damaged neural tissue and circuitry. This comprehensive review provides an in-depth analysis of the current state of stem cell applications in primary neurological conditions, including Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), stroke, spinal cord injury (SCI), and other related disorders. The review begins with a detailed introduction to stem cell biology, discussing the types, sources, and mechanisms of action of stem cells in neurological therapies. It then critically examines the preclinical evidence from animal models and early human trials investigating the safety, feasibility, and efficacy of different stem cell types, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), neural stem cells (NSCs), and induced pluripotent stem cells (iPSCs). While ESCs have been studied extensively in preclinical models, clinical trials have primarily focused on adult stem cells such as MSCs and NSCs, as well as iPSCs and their derivatives. We critically assess the current state of research for each cell type, highlighting their potential applications and limitations in different neurological conditions. The review synthesizes key findings from recent, high-quality studies for each neurological condition, discussing cell manufacturing, delivery methods, and therapeutic outcomes. While the potential of stem cells to replace lost neurons and directly reconstruct neural circuits is highlighted, the review emphasizes the critical role of paracrine and immunomodulatory mechanisms in mediating the therapeutic effects of stem cells in most neurological disorders. The article also explores the challenges and limitations associated with translating stem cell therapies into clinical practice, including issues related to cell sourcing, scalability, safety, and regulatory considerations. Furthermore, it discusses future directions and opportunities for advancing stem cell-based treatments, such as gene editing, biomaterials, personalized iPSC-derived therapies, and novel delivery strategies. The review concludes by emphasizing the transformative potential of stem cell therapies in revolutionizing the treatment of neurological disorders while acknowledging the need for rigorous clinical trials, standardized protocols, and multidisciplinary collaboration to realize their full therapeutic promise.

Standardisation is the key to the sustained, rapid and healthy development of stem cell-based therapy

BACKGROUND

Stem cell-based therapy (SCT) is an important component of regenerative therapy that brings hope to many patients. After decades of development, SCT has made significant progress in the research of various diseases, and the market size has also expanded significantly. The transition of SCT from small-scale, customized experiments to routine clinical practice requires the assistance of standards. Many countries and international organizations around the world have developed corresponding SCT standards, which have effectively promoted the further development of the SCT industry.

METHODS

We conducted a comprehensive literature review to introduce the clinical application progress of SCT and focus on the development status of SCT standardization.

RESULTS

We first briefly introduced the types and characteristics of stem cells, and summarized the current clinical application and market development of SCT. Subsequently, we focused on the development status of SCT-related standards as of now from three levels: the International Organization for Standardization (ISO), important international organizations, and national organizations. Finally, we provided perspectives and conclusions on the significance and challenges of SCT standardization.

CONCLUSIONS

Standardization plays an important role in the sustained, rapid and healthy development of SCT.

Rilparencel (Renal Autologous Cell Therapy-REACT®) for Chronic Kidney Disease and Type 1 and Type 2 Diabetes: Phase 2 Trial Design Evaluating Bilateral Kidney Dosing and Redosing Triggers

INTRODUCTION

Autologous cell-based therapies (CBT) to treat chronic kidney disease (CKD) with diabetes are novel and can potentially preserve renal function and decelerate disease progression. CBT dosing schedules are in early development and may benefit from individual bilateral organ dosing and kidney-dependent function to improve efficacy and durability. The objective of this open-label, phase 2 randomized controlled trial (RCT) is to evaluate participants' responses to rilparencel (Renal Autologous Cell Therapy-REACT®) following bilateral percutaneous kidney injections into the kidney cortex with a prescribed dosing schedule versus redosing based on biomarker triggers.

METHODS

Eligible participants with type 1 or 2 diabetes and CKD, eGFR 20-50 mL/min/1.73 m2, urine albumin-to-creatinine ratio (UACR) 30-5,000 mg/g, hemoglobin >10 g/dL, and glycosylated hemoglobin <10% were enrolled. After a percutaneous kidney biopsy and bioprocessing ex vivo expansion of selected renal cells, participants were randomized 1:1 into two cohorts determined by the dosing scheme. Cohort 1 receives 2 cell injections, one in each kidney 3 months apart, and cohort 2 receives one injection and the second dose only if there is a sustained eGFR decline of ≥20 mL/min/1.73 m2 and/or UACR increase of ≥30% and ≥30 mg/g, confirmed by re-testing.

CONCLUSION

The trial is fully enrolled with fifty-three participants. Cell injections and follow-up clinical visits are ongoing. This multicenter phase 2 RCT is designed to investigate the efficacy and safety of rilparencel with bilateral kidney dosing and compare two injection schedules with the potential of preserving or improving kidney function and delaying kidney disease progression among patients with stages 3a-4 CKD with diabetes.

Biomimetic injectable and bilayered hydrogel scaffold based on collagen and chondroitin sulfate for the repair of osteochondral defects

The simultaneous regeneration of articular cartilage and subchondral bone is a major challenge. Bioinspired scaffolds with distinct regions resembling stratified anatomical architecture provide a potential strategy for osteochondral defect repair. Here, we report the development of an injectable and bilayered hydrogel scaffold with a strong interface binding force. In this bilayer hydrogel, composed of carbonyl hydrazide grafted collagen (COL-CDH) and oxidized chondroitin sulfate (OCS), which are derivatives of osteochondral tissue components, in combination with poly (ethylene glycol) diacrylate (PEGDA), functions as a cartilage layer; while zinc-doped hydroxyapatite acts as a subchondral bone layer that is based on the cartilage layer. The strong interface between the two layers involves dynamic amide bonds formed between COL-CDH and OCS, and permanent CC bonds formed by PEGDA radical reactions. This bilayer hydrogel can be used to inoculate adipose mesenchymal stem cells which can then differentiate into chondrocytes and osteoblasts, secreting glycosaminoglycan, and promoting calcium deposition. This accelerates the regeneration of cartilage and subchondral bone. Micro-CT and tissue staining revealed an increase in the amount of bone present in new subchondral bone, and new tissues with a structure similar to normal cartilage. This study therefore demonstrates that injectable bilayer hydrogels are a promising scaffold for repairing osteochondral defects.

Microneedle-based cell delivery and cell sampling for biomedical applications

Cell-based therapeutics are novel therapeutic strategies that can potentially treat many presently incurable diseases through novel mechanisms of action. Cell therapies may benefit from the ease, safety, and efficacy of administering therapeutic cells. Despite considerable recent technological and biological advances, several barriers remain to the clinical translation and commercialization of cell-based therapies, including low patient compliance, personal handling inconvenience, poor biosafety, and limited biocompatibility. Microneedles (MNs) are emerging as a promising biomedical device option for improved cell delivery with little invasion, pain-free administration, and simplicity of disposal. MNs have shown considerable promise in treating a wide range of diseases and present the potential to improve cell-based therapies. In this review, we first summarized the latest advances in the various types of MNs developed for cell delivery and cell sampling. Emphasis was given to the design and fabrication of various types of MNs based on their structures and materials. Then we focus on the recent biomedical applications status of MNs-mediated cell delivery and sampling, including tissue repair (wound healing, heart repair, and endothelial repair), cancer treatment, diabetes therapy, cell sampling, and other applications. Finally, the current status of clinical application, potential perspectives, and the challenges for clinical translation are also highlighted.

Liposome-anchored mesenchymal stem cells for radiation pneumonia/fibrosis treatment

The effectiveness of mesenchymal stem cells (MSCs) on inflammation-related disease is limited and the pharmaceutical preparation that was used to enhance the efficacy of MSCs cannot reach the diseased tissue in large quantities. Herein, antioxidant liposome (Lipo-OPC) is designed to anchor onto the surface of MSCs membrane via click chemical reaction (MSC-Lipo-OPC) without affecting the viability and physiological characteristics of MSCs, thus allowing efficient accumulation of MSC-Lipo-OPC in X-ray irradiated lung sites. More importantly, MSC-Lipo-OPC promotes the change of the quantity and polarity of innate immunocytes, mainly including neutrophils, macrophages and Tregs, in favor of anti-inflammatory, finally preventing the formation of radioactive pulmonary fibrosis. Therefore, it could enhance the treatment outcome of both of MSCs and drugs to radiation-induced lung injury via modifying the drug-loaded nanoparticle on the surface of MSCs membrane, further promoting the application of MSCs in radiation damage and protection.

Scalable and Uniform Fabrication of Dexamethasone-Eluting Depot-Engineered Stem Cell Spheroids as a Microtissue Construct to Target Bone Regeneration

Potentiation of stem cell potency is critical for successful tissue engineering, especially for bone regeneration. Three-dimensional cell culture and bioactive molecule co-delivery with cells have been proposed to achieve this effect. Here, we provide a uniform and scalable fabrication of osteogenic microtissue constructs of mesenchymal stem cell (MSC) spheroids surface-engineered with dexamethasone-releasing polydopamine-coated microparticles (PD-DEXA/MPs) to target bone regeneration. The microparticle conjugation process was rapid and cell-friendly and did not affect the cell viability or key functionalities. The incorporation of DEXA in the conjugated system significantly enhanced the osteogenic differentiation of MSC spheroids, as evidenced by upregulating osteogenic gene expression and intense alkaline phosphatase and alizarin red S staining. In addition, the migration of MSCs from spheroids was tested on a biocompatible macroporous fibrin scaffold (MFS). The result showed that PD-DEXA/MPs were stably anchored on MSCs during cell migration over time. Finally, the implantation of PD-DEXA/MP-conjugated spheroid-loaded MFS into a calvarial defect in a mouse model showed substantial bone regeneration. In conclusion, the uniform fabrication of microtissue constructs containing MSC spheroids with drug depots shows a potential to improve the performance of MSCs in tissue engineering.

Enhanced Proliferation of Visualizable Mesenchymal Stem Cell-Platelet Hybrid Cell for Versatile Intracerebral Hemorrhage Treatment

The intrinsic features and functions of platelets and mesenchymal stem cells (MSCs) indicate their great potential in the treatment of intracerebral hemorrhage (ICH). However, neither of them can completely overcome ICH because of the stealth process and the complex pathology of ICH. Here, we fabricate hybrid cells for versatile and highly efficient ICH therapy by fusing MSCs with platelets and loading with lysophosphatidic acid-modified PbS quantum dots (LPA-QDs). The obtained LPA-QDs@FCs (FCs = fusion cells) not only inherit the capabilities of both platelets and MSCs but also exhibit clearly enhanced proliferation activated by LPA. After systemic administration, many proliferating LPA-QDs@FCs rapidly accumulate in ICH areas for responding to the vascular damage and inflammation and then efficiently prevent both the primary and secondary injuries of ICH but with no obvious side effects. Moreover, the treatment process can be tracked by near-infrared II fluorescence imaging with highly spatiotemporal resolution, providing a promising solution for ICH therapy.

Phenotyping of Macrophages After Radiolabeling and Safety of Intra-arterial Transplantation Assessed by SPECT/CT and MRI

Cell therapy is an integral modality of regenerative medicine. Macrophages are known for their sensitivity to activation stimuli and capability to recruit other immune cells to the sites of injury and healing. In addition, the route of administration can impact engraftment and efficacy of cell therapy, and modern neuro-interventional techniques provide the possibility for selective intra-arterial (IA) delivery to the central nervous system (CNS) with very low risk. The effects of radiolabelling and catheter transport on differentially activated macrophages were evaluated. Furthermore, the safety of selective IA administration of these macrophages to the rabbit brain was assessed by single-photon emission computed tomography/computed tomography (SPECT/CT) and ultra-high-field (9.4 T) magnetic resonance imaging (MRI). Cells were successfully labeled with (111In)In-(oxinate)3 and passed through a microcatheter with preserved phenotype. No cells were retained in the healthy rabbit brain after IA administration, and no adverse events could be observed either 1 h (n = 6) or 24 h (n = 2) after cell administration. The procedure affected both lipopolysaccharide/gamma interferon (LPS/IFNγ) activated cells and interleukin 4 (IL4), interleukin 10 (IL10)/transforming growth factor beta 1 (TGFβ1) activated cells to some degree. The LPS/IFNγ activated cells had a significant increase in their phagocytotic function. Overall, the major impact on the cell phenotypes was due to the radiolabeling and not passage through the catheter. Unstimulated cells were substantially affected by both radiolabeling and catheter administration and are hence not suited for this procedure, while both activated macrophages retained their initial phenotypes. In conclusion, activated macrophages are suitable candidates for targeted IA administration without adverse effects on normal, healthy brain parenchyma.

Engineering of hybrid spheroids of mesenchymal stem cells and drug depots for immunomodulating effect in islet xenotransplantation

Immunomodulation is an essential consideration for cell replacement procedures. Unfortunately, lifelong exposure to nonspecific systemic immunosuppression results in immunodeficiency and has toxic effects on nonimmune cells. Here, we engineered hybrid spheroids of mesenchymal stem cells (MSCs) with rapamycin-releasing poly(lactic-co-glycolic acid) microparticles (RAP-MPs) to prevent immune rejection of islet xenografts in diabetic C57BL/6 mice. Hybrid spheroids were rapidly formed by incubating cell-particle mixture in methylcellulose solution while maintaining high cell viability. RAP-MPs were uniformly distributed in hybrid spheroids and sustainably released RAP for ~3 weeks. Locoregional transplantation of hybrid spheroids containing low doses of RAP-MPs (200- to 4000-ng RAP per recipient) significantly prolonged islet survival times and promoted the generation of regional regulatory T cells. Enhanced programmed death-ligand 1 expression by MSCs was found to be responsible for the immunomodulatory performance of hybrid spheroids. Our results suggest that these hybrid spheroids offer a promising platform for the efficient use of MSCs in the transplantation field.

Melatonin enhances autologous adipose-derived stem cells to improve mouse ovarian function in relation to the SIRT6/NF-κB pathway

Background

Premature ovarian insufficiency (POI) is the main cause of female infertility. Adipose-derived stem cells (ADSCs) are ideal candidates for the treatment of POI. However, some deficient biological characteristics of ADSCs limit their utility. This study investigated whether melatonin (MLT)-pretreated autologous ADSCs were superior to ADSCs alone in the treatment of the POI mouse model.

Methods

Autologous ADSCs were isolated and cultured in MLT-containing medium. Surface markers of ADSCs were detected by flow cytometry. To determine the effect of MLT on ADSCs, CCK-8 assay was used to detect ADSCs proliferation and enzyme-linked immunosorbent assay (ELISA) was used to detect the secretion of cytokines. The POI model was established by intraperitoneal injection of cyclophosphamide and busulfan. Then, MLT-pretreated autologous ADSCs were transplanted into mice by intraovarian injection. After 7 days of treatment, ovarian morphology, follicle counts, and sex hormones levels were evaluated by hematoxylin and eosin (H&E) staining and ELISA, and the recovery of fertility was also observed. The expressions of SIRT6 and NF-κB were detected by immunohistochemical (IHC) staining and quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Flow cytometry showed that autologous ADSCs expressed CD90 (99.7%) and CD29 (97.5%). MLT can not only promote the proliferation of ADSCs but also boost their secretory function, especially when ADSCs were pretreated with 5 µM MLT for 3 days, improving the interference effect. After transplantation of autologous ADSCs pretreated with 5 µM MLT, the serum hormone levels and reproductive function were significantly recovered, and the mean counts of primordial follicle increased. At the same time, the expression of SIRT6 was remarkably increased and the expression of NF-κB was significantly decreased in this group.

Conclusions

MLT enhances several effects of ADSCs in restoring hormone levels, mean primordial follicle counts, and reproductive capacity in POI mice. Meanwhile, our results suggest that the SIRT6/NF-κB signal pathway may be the potential therapeutic mechanism for ADSCs to treat POI.

Engineering stem cell therapeutics for cardiac repair

Cardiovascular disease is the leading cause of death in the world. Stem cell-based therapies have been widely investigated for cardiac regeneration in patients with heart failure or myocardial infarction (MI) and surged ahead on multiple fronts over the past two decades. To enhance cellular therapy for cardiac regeneration, numerous engineering techniques have been explored to engineer cells, develop novel scaffolds, make constructs, and deliver cells or their derivatives. This review summarizes the state-of-art stem cell-based therapeutics for cardiac regeneration and discusses the emerged bioengineering approaches toward the enhancement of therapeutic efficacy of stem cell therapies in cardiac repair. We cover the topics in stem cell source and engineering, followed by stem cell-based therapies such as cell aggregates and cell sheets, and biomaterial-mediated stem cell therapies such as stem cell delivery with injectable hydrogel, three-dimensional scaffolds, and microneedle patches. Finally, we discuss future directions and challenges of engineering stem cell therapies for clinical translation.

Strategies for improving adipose-derived stem cells for tissue regeneration

Adipose-derived stem cells (ADSCs) have promising applications in tissue regeneration. Currently, there are only a few ADSC products that have been approved for clinical use. The clinical application of ADSCs still faces many challenges. Here, we review emerging strategies to improve the therapeutic efficacy of ADSCs in tissue regeneration. First, a great quantity of cells is often needed for the stem cell therapies, which requires the advanced cell expansion technologies. In addition cell-derived products are also required for the development of ‘cell-free’ therapies to overcome the drawbacks of cell-based therapies. Second, it is necessary to strengthen the regenerative functions of ADSCs, including viability, differentiation and paracrine ability, for the tissue repair and regeneration required for different physiological and pathophysiological conditions. Third, poor delivery efficiency also restricts the therapeutic effect of ADSCs. Effective methods to improve cell delivery include alleviating harsh microenvironments, enhancing targeting ability and prolonging cell retention. Moreover, we also point out some critical issues about the sources, effectiveness and safety of ADSCs. With these advanced strategies to improve the therapeutic efficacy of ADSCs, ADSC-based treatment holds great promise for clinical applications in tissue regeneration.

Stem Cell-Based Therapies: What Interventional Radiologists Need to Know

As the basic units of biological organization, stem cells and their progenitors are essential for developing and regenerating organs and tissue systems using their unique self-renewal capability and differentiation potential into multiple cell lineages. Stem cells are consistently present throughout the entire human development, from the zygote to adulthood. Over the past decades, significant efforts have been made in biology, genetics, and biotechnology to develop stem cell-based therapies using embryonic and adult autologous or allogeneic stem cells for diseases without therapies or difficult to treat. Stem cell-based therapies require optimum administration of stem cells into damaged organs to promote structural regeneration and improve function. Maximum clinical efficacy is highly dependent on the successful delivery of stem cells to the target tissue. Direct image-guided locoregional injections into target tissues offer an option to increase therapeutic outcomes. Interventional radiologists have the opportunity to perform a key role in delivering stem cells more efficiently using minimally invasive techniques. This review discusses the types and sources of stem cells and the current clinical applications of stem cell-based therapies. In addition, the regulatory considerations, logistics, and potential roles of interventional Radiology are also discussed with the review of the literature.

A novel minimally invasive OFM technique with orthotopic transplantation of hUC-MSCs and in vivo monitoring of liver metabolic microenvironment in liver fibrosis treatment

Background

Mesenchymal stromal cells (MSCs) transplantation showed promising therapeutic results in liver fibrosis. However, efficient cell delivery method is urgently needed and the therapeutic mechanism remains unclear. This study focused on developing a minimally invasive open-flow microperfusion (OFM) technique, which combined orthotopic transplantation of human umbilical cord-derived (hUC)-MSCs to liver and in vivo monitoring of liver microenvironment in mice with CCl₄-induced liver fibrosis.

Methods

The therapeutic potential of OFM route was evaluated by comparing OFM with intravenous (IV) injection route in terms of hUC-MSCs engraftment at the fibrosis liver, liver histopathological features, liver function and fibrotic markers expression after hUC-MSCs administration. OFM was also applied to sample liver interstitial fluid in vivo, and subsequent metabolomic analysis was performed to investigate metabolic changes in liver microenvironment.

Results

Compared with IV route, OFM route caused more hUC-MSCs accumulation in the liver and was more effective in improving the remodeling of liver structure and reducing collagen deposition in fibrotic liver. OFM transplantation of hUC-MSCs reduced blood ALT, AST, ALP and TBIL levels and increased ALB levels, to a greater extent than IV route. And OFM route appeared to have a more pronounced effect on ameliorating the CCl₄-induced up-regulation of the fibrotic markers, such as α-SMA, collagen I and TGF-β. In vivo monitoring of liver microenvironment demonstrated the metabolic perturbations induced by pathological condition and treatment intervention. Two metabolites and eight metabolic pathways, which were most likely to be associated with the liver fibrosis progression, were regulated by hUC-MSCs administration.

Conclusion

The results demonstrated that the novel OFM technique would be useful for hUC-MSCs transplantation in liver fibrosis treatment and for monitoring of the liver metabolic microenvironment to explore the underlying therapeutic mechanisms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02599-w.

Hypoxic mesenchymal stem cells ameliorate acute kidney ischemia-reperfusion injury via enhancing renal tubular autophagy

BACKGROUND

Acute kidney injury (AKI) is an emerging global healthcare issue without effective therapy yet. Autophagy recycles damaged organelles and helps maintain tissue homeostasis in acute renal ischemia-reperfusion (I/R) injury. Hypoxic mesenchymal stem cells (HMSCs) represent an innovative cell-based therapy in AKI. Moreover, the conditioned medium of HMSCs (HMSC-CM) rich in beneficial trophic factors may serve as a cell-free alternative therapy. Nonetheless, whether HMSCs or HMSC-CM mitigate renal I/R injury via modulating tubular autophagy remains unclear.

METHODS

Renal I/R injury was induced by clamping of the left renal artery with right nephrectomy in male Sprague-Dawley rats. The rats were injected with either PBS, HMSCs, or HMSC-CM immediately after the surgery and sacrificed 48 h later. Renal tubular NRK-52E cells subjected to hypoxia-reoxygenation (H/R) injury were co-cultured with HMSCs or treated with HMSC-CM to assess the regulatory effects of HSMCs on tubular autophagy and apoptosis. The association of tubular autophagy gene expression and renal recovery was also investigated in patients with ischemic AKI.

RESULT

HMSCs had a superior anti-oxidative effect in I/R-injured rat kidneys as compared to normoxia-cultured mesenchymal stem cells. HMSCs further attenuated renal macrophage infiltration and inflammation, reduced tubular apoptosis, enhanced tubular proliferation, and improved kidney function decline in rats with renal I/R injury. Moreover, HMSCs suppressed superoxide formation, reduced DNA damage and lipid peroxidation, and increased anti-oxidants expression in renal tubular epithelial cells during I/R injury. Co-culture of HMSCs with H/R-injured NRK-52E cells also lessened tubular cell death. Mechanistically, HMSCs downregulated the expression of pro-inflammatory interleukin-1β, proapoptotic Bax, and caspase 3. Notably, HMSCs also upregulated the expression of autophagy-related LC3B, Atg5 and Beclin 1 in renal tubular cells both in vivo and in vitro. Addition of 3-methyladenine suppressed the activity of autophagy and abrogated the renoprotective effects of HMSCs. The renoprotective effect of tubular autophagy was further validated in patients with ischemic AKI. AKI patients with higher renal LC3B expression were associated with better renal recovery.

CONCLUSION

The present study describes that the enhancing effect of MSCs, and especially of HMCSs, on tissue autophagy can be applied to suppress renal tubular apoptosis and attenuate renal impairment during renal I/R injury in the rat. Our findings provide further mechanistic support to HMSCs therapy and its investigation in clinical trials of ischemic AKI.