Adipose tissue-derived mesenchymal stem cells as a source of human hepatocytes

Advances in therapies using mesenchymal stem cells and their exosomes for treatment of peripheral nerve injury: state of the art and future perspectives

"Peripheral nerve injury" refers to damage or trauma affecting nerves outside the brain and spinal cord. Peripheral nerve injury results in movements or sensation impairments, and represents a serious public health problem. Although severed peripheral nerves have been effectively joined and various therapies have been offered, recovery of sensory or motor functions remains limited, and efficacious therapies for complete repair of a nerve injury remain elusive. The emerging field of mesenchymal stem cells and their exosome-based therapies hold promise for enhancing nerve regeneration and function. Mesenchymal stem cells, as large living cells responsive to the environment, secrete various factors and exosomes. The latter are nano-sized extracellular vesicles containing bioactive molecules such as proteins, microRNA, and messenger RNA derived from parent mesenchymal stem cells. Exosomes have pivotal roles in cell-to-cell communication and nervous tissue function, offering solutions to changes associated with cell-based therapies. Despite ongoing investigations, mesenchymal stem cells and mesenchymal stem cell-derived exosome-based therapies are in the exploratory stage. A comprehensive review of the latest preclinical experiments and clinical trials is essential for deep understanding of therapeutic strategies and for facilitating clinical translation. This review initially explores current investigations of mesenchymal stem cells and mesenchymal stem cell-derived exosomes in peripheral nerve injury, exploring the underlying mechanisms. Subsequently, it provides an overview of the current status of mesenchymal stem cell and exosome-based therapies in clinical trials, followed by a comparative analysis of therapies utilizing mesenchymal stem cells and exosomes. Finally, the review addresses the limitations and challenges associated with use of mesenchymal stem cell-derived exosomes, offering potential solutions and guiding future directions.

The Potential Hepatocyte Differentiation Targets and MSC Proliferation by FH1

The main cause of acute liver failure (ALF) is hepatocellular necrosis, which induces liver repair dysfunction and leads to high mortality. In recent years, studies have increasingly shown that stem cell-derived hepatocyte-like cells (HLCs) can be used for treatment in animal models of ALF. Notably, a hepatocyte differentiation strategy based on the small-molecule compound functional hit 1 (FH1) successfully replaces HGF to promote the maturation of HLCs, but the underlying mechanism is still unclear. In this study, we used network pharmacology analysis to clarify the important role of the HGF/c-Met signalling pathway in FH1-induced hepatocyte (FH1-iHeps) differentiation. After FH1 was added to mesenchymal stem/stromal cells (MSCs), proliferation and cell cycle progression were rescued by treatment with a tyrosine kinase (c-Met) inhibitor. Additionally, c-Met signalling in MSCs was significantly increased by treatment with FH1, as shown by the increased c-Met, p-p38, p-AKT and p-ERK1/2 protein levels. FH1-iHeps efficiently improved the liver function of mice with acute liver injury and prolonged their lifespan. These data provide new insight into the mechanisms regulating the stemness properties of human umbilical cord-derived stem cells (hUC-MSCs) and reveal a previously unrecognised link between FH1 and c-Met in directing hepatocyte differentiation.

3D printing incorporating gold nanozymes with mesenchymal stem cell-derived hepatic spheroids for acute liver failure treatment

Acute liver failure (ALF) is a highly fatal disease, necessitating the advancement and optimization of alternative therapeutic strategies to benefit patients awaiting liver transplantation. In this study, we innovatively established the antioxidant nanozyme-hepatocyte-like cells (HLCs) microtissue sheets (HS/N-Au@composite) for ALF therapy. We first prepared a 3D-printed hyaluronic acid/gelatin/sodium alginate scaffold with N-acetylcysteine (NAC)-capped gold nanoclusters (NAC-Au NCs), forming the N-Au@hydrogel. For the encapsulation of HLC spheroids, we used a biocompatible hybrid hydrogel composed of decellularized extracellular matrix (dECM), thrombin, and fibrinogen, resulting in the HS@dECM hydrogel. Utilizing 3D printing technology, we integrated the N-Au@hydrogel with the HS@dECM hydrogel to create the HS/N-Au@composite for in situ transplantation to treat ALF. Our results demonstrated that NAC-Au NCs effectively mitigated reactive oxygen species (ROS)-induced liver necrosis in ALF. Additionally, the N-Au@hydrogel provided mechanical support, ensuring the proper landing and effective functioning of the transplanted HLC spheroids. The HS/N-Au@composite synergistically decreased serum transaminase levels, reduced the accumulation of pro-inflammatory cytokines, accelerated liver function recovery, and promoted liver regeneration in ALF treatment. This combination of HLC spheroids and NAC-Au NCs nanozymes via 3D-printed composite scaffolds represents a promising strategy for enhancing hepatocyte transplantation and advancing stem cell regenerative medicine in ALF therapy.

Revolutionizing Cancer Treatment: Harnessing the Power of Mesenchymal Stem Cells for Precise Targeted Therapy in the Tumor Microenvironment

In recent years, mesenchymal stem cells (MSCs) have emerged as promising anti-- cancer mediators with the potential to treat several cancers. MSCs have been modified to produce anti-proliferative, pro-apoptotic, and anti-angiogenic molecules that could be effective against a variety of malignancies. Additionally, customizing MSCs with cytokines that stimulate pro-tumorigenic immunity or using them as vehicles for traditional chemical molecules with anti-cancer characteristics. Even though the specific function of MSCs in tumors is still challenged, promising outcomes from preclinical investigations of MSC-based gene therapy for a variety of cancers inspire the beginning of clinical trials. In addition, the tumor microenvironment (TME) could have a substantial influence on normal tissue stem cells, which can affect the treatment outcomes. To overcome the complications of TME in cancer development, MSCs could provide some signs of hope for converting TME into unequivocal therapeutic tools. Hence, this review focuses on engineered MSCs (En-MSCs) as a promising approach to overcoming the complications of TME.

Administration of Adipose-Derived Stem Cells After the Onset of the Disease Does Not Lower the Levels of Inflammatory Cytokines IL1 and IL6 in a Rat Model of Necrotizing Enterocolitis

Background/Objectives: Research on the roles of stem cells in necrotizing enterocolitis (NEC) has primarily focused on the effects of bone marrow- and amniotic fluid-derived stem cells in mitigating the clinical manifestations of the disease. However, the potential of adipose tissue-derived stem cells (ADSCs) remains unexplored in this context. The aim of this study was to evaluate the therapeutic potential of ADSC administration during the active inflammatory phase of NEC, with a specific focus on reducing the levels of the inflammatory cytokines IL-1 and IL-6. Methods: A self-modified hypoxia-hypothermia-formula feeding rat NEC model was employed. A total of 117 rat pups were divided into two groups: a treatment group (NEC-ADSC, n = 55) and a control group (NEC-PLCB (placebo), n = 62). In the NEC-ADSC group, ADSCs were administered intraperitoneally 24 h into the NEC protocol. After 72 h, bowel and fluid samples were collected for analysis. Results: The analysis revealed no significant effect on NEC histopathology (p = 0.347) or on the levels of IL-1 and IL-6 (p = 0.119 and p = 0.414, respectively). Conclusions: The administration of adipose tissue-derived stem cells after the onset of necrotizing enterocolitis does not reduce the levels of inflammatory cytokines IL-1 and IL-6, nor does it influence the histopathological outcomes of the disease in the rat model. Further research is needed to explore the potential therapeutic role of adipose tissue-derived stem cells in the treatment of necrotizing enterocolitis.

Substance P alleviates liver fibrosis by modulating inflammation and mobilizing reparative stem cells

Repetitive hepatic damage resulting from viral hepatitis, toxins, and alcohol abuse induces chronic inflammation and excessive accumulation of the extracellular matrix, leading to the development of liver cirrhosis. Substance P (SP) promotes endogenous wound healing by mobilizing bone marrow stem cells and stimulating anti-inflammatory responses. This study aimed to investigate whether SP exerts a therapeutic effect on liver fibrosis by recruiting endogenous stem cells and modulating immune responses. A non-clinical model of liver cirrhosis was established through repeated injections of thioacetamide and recombinant leptin. After confirming liver fibrosis, SP was administered intravenously for 6 weeks. SP treatment decreased the formation of hepatic micronodules on the external surface of the liver and the infiltration of immune cells. Furthermore, SP treatment notably reduced the deposition of collagen and the activation of hepatic stellate cells, concomitant with decreased levels of transforming growth factor-β1 and matrix metalloproteinase activity. In the context of severe hepatic damage, SP increased the number of circulating stem cells, leading to the restoration of the reparative stem cell pool in the bone marrow. The findings of this study suggest that SP alleviates liver fibrosis by modulating the mobilization of functional stem cells and the immune response.

Cell therapy for end-stage liver disease: Current state and clinical challenge

ABSTRACT

Liver disease involves a complex interplay of pathological processes, including inflammation, hepatocyte necrosis, and fibrosis. End-stage liver disease (ESLD), such as liver failure and decompensated cirrhosis, has a high mortality rate, and liver transplantation is the only effective treatment. However, to overcome problems such as the shortage of donor livers and complications related to immunosuppression, there is an urgent need for new treatment strategies that need to be developed for patients with ESLD. For instance, hepatocytes derived from donor livers or stem cells can be engrafted and multiplied in the liver, substituting the host hepatocytes and rebuilding the liver parenchyma. Stem cell therapy, especially mesenchymal stem cell therapy, has been widely proved to restore liver function and alleviate liver injury in patients with severe liver disease, which has contributed to the clinical application of cell therapy. In this review, we discussed the types of cells used to treat ESLD and their therapeutic mechanisms. We also summarized the progress of clinical trials around the world and provided a perspective on cell therapy.

Mesenchymal stem cells lineage and their role in disease development

BACKGROUND

Mesenchymal stem cells (MSCs) are widely dispersed in vivo and are isolated from several tissues, including bone marrow, heart, body fluids, skin, and perinatal tissues. Bone marrow MSCs have a multidirectional differentiation potential, which can be induced to differentiate the medium in a specific direction or by adding specific regulatory factors. MSCs repair damaged tissues through lineage differentiation, and the ex vivo transplantation of bone marrow MSCs can heal injured sites. MSCs have different propensities for lineage differentiation and pathological evolution for different diseases, which are crucial in disease progression. In this study, we describe various lineage analysis methods to explore lineage ontology in vitro and in vivo, elucidate the impact of MSC lineage differentiation on diseases, advance our understanding of the role of MSC differentiation in physiological and pathological states, and explore new targets and ideas associated with disease diagnosis and treatment.

Administration of Adipose Tissue Derived Stem Cells before the Onset of the Disease Lowers the Levels of Inflammatory Cytokines IL-1 and IL-6 in the Rat Model of Necrotizing Enterocolitis

There is little research concerning the role of stem cells in necrotizing enterocolitis (NEC). Bone marrow-derived mesenchymal stem cells (BMDSC) and amniotic fluid-derived stem cells significantly reduced the amount and severity of NEC in the animal models. ADSCs share similar surface markers and differentiation potential with BMDSCs. Their potential role in the setting of NEC has not been researched before. The hypothesis of the study was that prophylactic intraperitoneal administration of ADSCs before the onset of the disease will result in limiting the inflammatory response, effecting a lower incidence of NEC. On a molecular level, this should result in lowering the levels of inflammatory cytokines IL-1 and IL-6. The local ethical committee for animal experiments approval was acquired (WAW2/093/2021). We utilized a self-modified rat NEC model based on single exposure to hypothermia, hypoxia, and formula feeding. One hundred and twenty-eight rat puppies were divided into two groups-prophylaxis (ADSC-NEC, n = 66) and control group (NEC-PLCB, n = 62)-to measure the influence of ADSCs administration on the inflammatory changes in NEC, the level of cell engraftment, and the histopathology of the disease. The analysis did not show a significant effect on histopathology between groups, H(2) = 2.12; p = 0.347; η²H = 0.00. The intensity of the NEC variable results was similar across the analyzed groups (NEC-PLCB and ADSC-NEC). For IL-1 and IL-6, the difference between the NEC-PLCB group and the ADSC-NEC group was statistically significant, p = 0.002 and p < 0.001, respectively. To conclude, administration of adipose tissue-derived stem cells before the onset of the disease lowers the levels of inflammatory cytokines IL-1 and IL-6 but does not affect the histopathological results in the rat model of NEC.

Ohwia caudata aqueous extract attenuates senescence in aging adipose-derived mesenchymal stem cells

Stem cells exhibit pluripotency and self-renewal abilities. Adipose-derived mesenchymal stem cells can potentially be used to reconstruct various tissues. They possess significant versatility and alleviate various aging-related diseases. Unfortunately, aging leads to senescence, apoptosis, and a decline in regenerative capacity in adipose-derived mesenchymal stem cells. These changes necessitate a strategy to mitigate the effects of aging on stem cells. Ohwia caudata (O. caudata) has therapeutic effects against several illnesses. However, studies on whether O. caudata has therapeutic effects against aging are lacking. In this study, we aimed to identify potential therapeutic anti-aging effects in the crude aqueous extract of O. caudata on adipose-derived mesenchymal stem cells. Using 0.1 μM doxorubicin, we induced aging in human adipose-derived mesenchymal stem cells (hADMSCs) and evaluated whether various concentrations of O. caudata aqueous extract exhibit anti-aging effects on them. The O. caudata extract exhibited significant antioxidant effects on hADMSCs without any toxicity. Furthermore, after treatment with the O. caudata aqueous extract, the levels of mitochondrial superoxide, DNA double-strand breaks, and telomere shortening were reduced in the hADMSCs subjected to doxorubicin-induced aging. The extract also suppressed doxorubicin-induced aging by upregulating klotho and downregulating p21 in hADMSCs. These findings indicated that the O. caudata extract exhibited anti-aging properties that modulated hADMSC homeostasis. Therefore, it could be a potential candidate for restoring the self-renewal ability and multipotency of aging hADMSCs.

Immortalized hepatocyte-like cells: A competent hepatocyte model for studying clinical HCV isolate infection

More than 58 million individuals worldwide are inflicted with chronic HCV. The disease carries a high risk of end stage liver disease, i.e., cirrhosis and hepatocellular carcinoma. Although direct-acting antiviral agents (DAAs) have revolutionized therapy, the emergence of drug-resistant strains has become a growing concern. Conventional cellular models, Huh7 and its derivatives were very permissive to only HCVcc (JFH-1), but not HCV clinical isolates. The lack of suitable host cells had hindered comprehensive research on patient-derived HCV. Here, we established a novel hepatocyte model for HCV culture to host clinically pan-genotype HCV strains. The immortalized hepatocyte-like cell line (imHC) derived from human mesenchymal stem cell carries HCV receptors and essential host factors. The imHC outperformed Huh7 as a host for HCV (JFH-1) and sustained the entire HCV life cycle of pan-genotypic clinical isolates. We analyzed the alteration of host markers (i.e., hepatic markers, cellular innate immune response, and cell apoptosis) in response to HCV infection. The imHC model uncovered the underlying mechanisms governing the action of IFN-α and the activation of sofosbuvir. The insights from HCV-cell culture model hold promise for understanding disease pathogenesis and novel anti-HCV development.

Engineered 3D liver-tissue model with minispheroids formed by a bioprinting process supported with in situ electrical stimulation

Three-dimensional (3D) bioprinting, an effective technique for building cell-laden structures providing native extracellular matrix environments, presents challenges, including inadequate cellular interactions. To address these issues, cell spheroids offer a promising solution for improving their biological functions. Particularly, minispheroids with 50-100 μm diameters exhibit enhanced cellular maturation. We propose a one-step minispheroid-forming bioprinting process incorporating electrical stimulation (E-MS-printing). By stimulating the cells, minispheroids with controlled diameters were generated by manipulating the bioink viscosity and stimulation intensity. To validate its feasibility, E-MS-printing process was applied to fabricate an engineered liver model designed to mimic the hepatic lobule unit. E-MS-printing was employed to print the hepatocyte region, followed by bioprinting the central vein using a core-shell nozzle. The resulting constructs displayed native liver-mimetic structures containing minispheroids, which facilitated improved hepatic cell maturation, functional attributes, and vessel formation. Our results demonstrate a new potential 3D liver model that can replicate native liver tissues.

Adipose-Derived Stem Cells: Angiogenetic Potential and Utility in Tissue Engineering

Adipose tissue (AT) is a large and important energy storage organ as well as an endocrine organ with a critical role in many processes. Additionally, AT is an enormous and easily accessible source of multipotent cell types used in our day for all types of tissue regeneration. The ability of adipose-derived stem cells (ADSCs) to differentiate into other types of cells, such as endothelial cells (ECs), vascular smooth muscle cells, or cardiomyocytes, is used in tissue engineering in order to promote/stimulate the process of angiogenesis. Being a key for future successful clinical applications, functional vascular networks in engineered tissue are targeted by numerous in vivo and ex vivo studies. The article reviews the angiogenic potential of ADSCs and explores their capacity in the field of tissue engineering (TE).

Stem cell-derived hepatocyte therapy using versatile biomimetic nanozyme incorporated nanofiber-reinforced decellularized extracellular matrix hydrogels for the treatment of acute liver failure

Reactive oxygen species (ROS)-associated oxidative stress, inflammation storm, and massive hepatocyte necrosis are the typical manifestations of acute liver failure (ALF), therefore specific therapeutic interventions are essential for the devastating disease. Here, we developed a platform consisting of versatile biomimetic copper oxide nanozymes (Cu NZs)-loaded PLGA nanofibers (Cu NZs@PLGA nanofibers) and decellularized extracellular matrix (dECM) hydrogels for delivery of human adipose-derived mesenchymal stem/stromal cells-derived hepatocyte-like cells (hADMSCs-derived HLCs) (HLCs/Cu NZs@fiber/dECM). Cu NZs@PLGA nanofibers could conspicuously scavenge excessive ROS at the early stage of ALF, and reduce the massive accumulation of pro-inflammatory cytokines, herein efficiently preventing the deterioration of hepatocytes necrosis. Moreover, Cu NZs@PLGA nanofibers also exhibited a cytoprotection effect on the transplanted HLCs. Meanwhile, HLCs with hepatic-specific biofunctions and anti-inflammatory activity acted as a promising alternative cell source for ALF therapy. The dECM hydrogels further provided the desirable 3D environment and favorably improved the hepatic functions of HLCs. In addition, the pro-angiogenesis activity of Cu NZs@PLGA nanofibers also facilitated the integration of the whole implant with the host liver. Hence, HLCs/Cu NZs@fiber/dECM performed excellent synergistic therapeutic efficacy on ALF mice. This strategy using Cu NZs@PLGA nanofiber-reinforced dECM hydrogels for HLCs in situ delivery is a promising approach for ALF therapy and shows great potential for clinical translation.

Arouse potential stemness: Intrinsic and acquired stem cell therapeutic strategies for advanced liver diseases

Liver diseases are a major health issue, and prolonged liver injury always progresses. Advanced liver disorders impair liver regeneration. Millions of patients die yearly worldwide, even with the available treatments of liver transplantation and artificial liver support system. With its abundant cell resources and significant differentiative potential, stem cell therapy is a viable treatment for various disorders and offers hope to patients waiting for orthotopic liver transplantation. Considering such plight, stem cell therapeutic strategies deliver hope to the patients. Moreover, we conclude intrinsic and acquired perspectives based on stem cell sources. The properties and therapeutic uses of these stem cells' specific types or sources were then reviewed. Owing to the recent investigations of the above cells, a safe and effective therapy will emerge for advanced liver diseases soon.

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.

Liver Disease and Cell Therapy: Advances Made and Remaining Challenges

The limited availability of organs for liver transplantation, the ultimate curative treatment for end stage liver disease, has resulted in a growing and unmet need for alternative therapies. Mesenchymal stromal cells (MSCs) with their broad ranging anti-inflammatory and immunomodulatory properties have therefore emerged as a promising therapeutic agent in treating inflammatory liver disease. Significant strides have been made in exploring their biological activity. Clinical application of MSC has shifted the paradigm from using their regenerative potential to one which harnesses their immunomodulatory properties. Reassuringly, MSCs have been extensively investigated for over 30 years with encouraging efficacy and safety data from translational and early phase clinical studies, but questions remain about their utility. Therefore, in this review, we examine the translational and clinical studies using MSCs in various liver diseases and their impact on dampening immune-mediated liver damage. Our key observations include progress made thus far with use of MSCs for clinical use, inconsistency in the literature to allow meaningful comparison between different studies and need for standardized protocols for MSC manufacture and administration. In addition, the emerging role of MSC-derived extracellular vesicles as an alternative to MSC has been reviewed. We have also highlighted some of the remaining clinical challenges that should be addressed before MSC can progress to be considered as therapy for patients with liver disease.

Mesenchymal stromal cells in hepatic fibrosis/cirrhosis: from pathogenesis to treatment

Hepatic fibrosis/cirrhosis is a significant health burden worldwide, resulting in liver failure or hepatocellular carcinoma (HCC) and accounting for many deaths each year. The pathogenesis of hepatic fibrosis/cirrhosis is very complex, which makes treatment challenging. Endogenous mesenchymal stromal cells (MSCs) have been shown to play pivotal roles in the pathogenesis of hepatic fibrosis. Paradoxically, exogenous MSCs have also been used in clinical trials for liver cirrhosis, and their effectiveness has been observed in most completed clinical trials. There are still many issues to be resolved to promote the use of MSCs in the clinic in the future. In this review, we will examine the controversial role of MSCs in the pathogenesis and treatment of hepatic fibrosis/cirrhosis. We also investigated the clinical trials involving MSCs in liver cirrhosis, summarized the parameters that need to be standardized, and discussed how to promote the use of MSCs from a clinical perspective.

Cellular therapies in liver and pancreatic diseases

Over the past two decades, developments in regenerative medicine in gastroenterology have been greatly enhanced by the application of stem cells, which can self-replicate and differentiate into any somatic cell. The discovery of induced pluripotent stem cells has opened remarkable perspectives on tissue regeneration, including their use as a bridge to transplantation or as supportive therapy in patients with organ failure. The improvements in DNA manipulation and gene editing strategies have also allowed to clarify the physiopathology and to correct the phenotype of several monogenic diseases, both in vivo and in vitro. Further progress has been made with the development of three-dimensional cultures, known as organoids, which have demonstrated morphological and functional complexity comparable to that of a miniature organ. Hence, owing to its protean applications and potential benefits, cell and organoid transplantation has become a hot topic for the management of gastrointestinal diseases. In this review, we describe current knowledge on cell therapies in hepatology and pancreatology, providing insight into their future applications in regenerative medicine.

Therapeutic potential of small extracellular vesicles derived from mesenchymal stem cells for spinal cord and nerve injury

Neural diseases such as compressive, congenital, and traumatic injuries have diverse consequences, from benign mild sequelae to severe life-threatening conditions with associated losses of motor, sensory, and autonomic functions. Several approaches have been adopted to control neuroinflammatory cascades. Traditionally, mesenchymal stem cells (MSCs) have been regarded as therapeutic agents, as they possess growth factors and cytokines with potential anti-inflammatory and regenerative effects. However, several animal model studies have reported conflicting outcomes, and therefore, the role of MSCs as a regenerative source for the treatment of neural pathologies remains debatable. In addition, issues such as heterogeneity and ethical issues limited their use as therapeutic agents. To overcome the obstacles associated with the use of traditional agents, we explored the therapeutic potentials of extracellular vesicles (EVs), which contain nucleic acids, functional proteins, and bioactive lipids, and play crucial roles in immune response regulation, inflammation reduction, and cell-to-cell communication. EVs may surpass MSCs in size issue, immunogenicity, and response to the host environment. However, a comprehensive review is required on the therapeutic potential of EVs for the treatment of neural pathologies. In this review, we discuss the action mechanism of EVs, their potential for treating neural pathologies, and future perspectives regarding their clinical applications.

Mechanisms of Action of Mesenchymal Stem Cells in Metabolic-Associated Fatty Liver Disease

Metabolic-associated fatty liver disease (MAFLD) is currently the most common chronic liver disease worldwide. However, its pathophysiological mechanism is complicated, and currently, it has no FDA-approved pharmacological therapies. In recent years, mesenchymal stem cell (MSC) therapy has attracted increasing attention in the treatment of hepatic diseases. MSCs are multipotent stromal cells that originated from mesoderm mesenchyme, which have self-renewal and multipotent differentiation capability. Recent experiments and studies have found that MSCs have the latent capacity to be used for MAFLD treatment. MSCs have the potential to differentiate into hepatocytes, which could be induced into hepatocyte-like cells (HLCs) with liver-specific morphology and function under appropriate conditions to promote liver tissue regeneration. They can also reduce liver tissue injury and reverse the development of MAFLD by regulating immune response, antifibrotic activities, and lipid metabolism. Moreover, several advantages are attributed to MSC-derived exosomes (MSC-exosomes), such as targeted delivery, reliable reparability, and poor immunogenicity. After entering the target cells, MSC-exosomes help regulate cell function and signal transduction; thus, it is expected to become an emerging treatment for MAFLD. In this review, we comprehensively discussed the roles of MSCs in MAFLD, main signaling pathways of MSCs that affect MAFLD, and mechanisms of MSC-exosomes on MAFLD.

Role of Nrf2 signaling in development of hepatocyte-like cells

Generation of hepatocytes from human adipose-derived mesenchymal stem cells (hADSCs) could be a promising alternative source of human hepatocytes. However, mechanisms to differentiate hepatocytes from hADSCs are not fully elucidated. We have previously demonstrated that our three-step differentiation protocol with glycogen synthase kinase (GSK) 3 inhibitor was effective to improve hepatocyte functions. In this study, we investigated the activation of the nuclear factor erythroid-2 related factor 2 (Nrf2) on hADSCs undergoing differentiation to HLC (hepatocyte-like cells). Our three-step differentiation protocol was applied for 21 days (Step 1:day 1-6, Step2:day 6-11, Step3:day 11-21). Our results show that significant nuclear translocation of Nrf2 occurred from day 11 until the end of HLC differentiation. Nuclear translocation of Nrf2 and CYP3A4 activity in the GSK3 inhibitor-treated group was obviously higher than that in Activin A-treated groups at day 11. The maturation of HLCs was delayed in Nrf2-siRNA group compared to control group. Furthermore, CYP3A4 activity in Nrf2-siRNA group was decreased at the almost same level in Activin A-treated group. Nrf2 translocation might enhance the function of HLC and be a target for developing highly functional HLC. J. Med. Invest. 70 : 343-349, August, 2023.

Mechanism of Mesenchymal Stem Cells as a Multitarget Disease- Modifying Therapy for Parkinson's Disease

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders, affecting the basal nuclei, causing impairment of motor and cognitive functions. Loss of dopaminergic (DAergic) neurons or their degeneration and the aggregation of Lewy bodies is the hallmark of this disease. The medications used to treat PD relieve the symptoms and maintain quality of life, but currently, there is no cure. There is a need for the development of therapies that can cease or perhaps reverse neurodegeneration effectively. With the rapid advancements in cell replacement therapy techniques, medical professionals are trying to find a cure by which restoration of dopamine neurotransmitters can occur. Researchers have started focusing on cell-based therapies using mesenchymal stem cells (MSCs) due to their abundance in the body, the ability of proliferation, and immunomodulation. Here we review the MSC-based treatment in Parkinson's disease and the various mechanisms it repairs DAergic neurons in parkinsonian patients.

Functional Evaluation of 3D Liver Models Labeled with Polysaccharide Functionalized Magnetic Nanoparticles

Establishing a rapid in vitro evaluation system for drug screening is essential for the development of new drugs. To reproduce tissues/organs with functions closer to living organisms, in vitro three-dimensional (3D) culture evaluation using microfabrication technology has been reported in recent years. Culture on patterned substrates with controlled hydrophilic and hydrophobic regions (Cell-able^TM) can create 3D liver models (miniature livers) with liver-specific Disse luminal structures and functions. MRI contrast agents are widely used as safe and minimally invasive diagnostic methods. We focused on anionic polysaccharide magnetic iron oxide nanoparticles (Resovist^®) and synthesized the four types of nanoparticle derivatives with different properties. Cationic nanoparticles (TMADM) can be used to label target cells in a short time and have been successfully visualized in vivo. In this study, we examined the morphology of various nanoparticles. The morphology of various nanoparticles showed relatively smooth-edged spherical shapes. As 3D liver models, we prepared primary hepatocyte-endothelial cell heterospheroids. The toxicity, CYP3A, and albumin secretory capacity were evaluated in the heterospheroids labeled with various nanoparticles. As the culture period progressed, the heterospheroids labeled with anionic and cationic nanoparticles showed lower liver function than non-labeled heterospheroids. In the future, there is a need to improve the method of creation of artificial 3D liver or to design a low-invasive MRI contrast agent to label the artificial 3D liver.

Stem Cell Therapies for Chronic Liver Diseases: Progress and Challenges

Chronic liver diseases have become a significant health issue worldwide and urgently require the development of novel therapeutic approaches, in addition to liver transplantation. Recent clinical and preclinical studies have shown that cell-based therapeutic strategies may contribute to the improvement of chronic liver diseases and offer new therapeutic options to restore liver function through their roles in tissue impairment and immunomodulation. In this review, we summarize the current progress and analyze the challenges for different types of cell therapies used in the treatment of chronic liver diseases currently explored in clinical trials and preclinical studies in animal models. We also discuss some critical issues regarding the use of mesenchymal stem cells (MSCs, the most extensive cell source of stem cells), including therapeutic dosage, transfusion routine, and pharmacokinetics/pharmacodynamics (PK/PD) of transfused MSCs.

Cellular Therapies in Pediatric Liver Diseases

Liver transplantation is the gold standard for the treatment of pediatric end-stage liver disease and liver based metabolic disorders. Although liver transplant is successful, its wider application is limited by shortage of donor organs, surgical complications, need for life long immunosuppressive medication and its associated complications. Cellular therapies such as hepatocytes and mesenchymal stromal cells (MSCs) are currently emerging as an attractive alternative to liver transplantation. The aim of this review is to present the existing world experience in hepatocyte and MSC transplantation and the potential for future effective applications of these modalities of treatment.

Potential mesenchymal stem cell therapeutics for treating primary biliary cholangitis: advances, challenges, and perspectives

Primary biliary cholangitis (PBC) is a cholestatic autoimmune liver disease characterized by the gradual destruction of small intrahepatic bile ducts that eventually leads to liver cirrhosis, failure, and even carcinoma. The treatment options for PBC are limited, and the main treatment choices are the US Food and Drug Administration–approved ursodeoxycholic acid and obeticholic acid. However, many patients fail to respond adequately to these drugs and the adverse effects frequently lead to low life quality. For patients with end-stage PBC, liver transplantation remains the only effective treatment. Given their low immunogenicity, prominent immunomodulation property, differentiation potential, and tissue maintenance capacity, mesenchymal stem cells (MSCs) are emerging as new options for treating liver diseases, including PBC. Accumulating evidence from basic research to clinical studies supports the positive effects of MSC-based therapy for treating PBC. In this review, we characterized the underlying roles and mechanisms of MSCs for treating liver diseases and highlight recent basic and clinical advances in MSC-based therapy for treating PBC. Finally, the current challenges and perspectives for MSC-based therapy in clinical application are discussed, which could help accelerate the application of MSCs in clinical practice, especially for refractory diseases such as PBC.

Surface Functionalized Polyaniline Nanofibers:Chitosan Nanocomposite for Promoting Neuronal-like Differentiation of Primary Adipose Derived Mesenchymal Stem Cells and Urease Activity

Bioscaffolds having electrically conducting polymers (CPs) have become increasingly relevant in tissue engineering (TE) because of their ability to regulate conductivity and promote biological function. With this in mind, the current study shows a conducting polyaniline nanofibers (PNFs) dispersed chitosan (Ch) nanocomposites scaffold with a simple one-step surface functionalization approach using glutaraldehyde for potential neural regeneration applications. According to the findings, 4 wt % PNFs dispersion in Ch matrix is an optimal concentration for achieving desirable biological functions while maintaining required physicochemical properties as evidenced by SEM, XRD, current-voltage (I-V) measurement, mechanical strength test, and in vitro biodegradability test. Surface chemical compositional analysis using XPS and ATR FT-IR confirms the incorporation of aldehyde functionality after functionalization, which is corroborated by surface energy calculations following the Van Oss-Chaudhury-Good method. Surface functionalization induced enhancement in surface hydrophilicity in terms of the polar component of surface energy (γ_i^AB) from 6.35 to 12.54 mN m^-1 along with an increase in surface polarity from 13.61 to 22.54%. Functionalized PNF:Ch scaffolds demonstrated improvement in enzyme activity from 67 to 94% and better enzyme kinetics with a reduction of Michaelis constants (K_m) from 21.55 to 13.81 mM, indicating favorable protein-biomaterial interactions and establishing them as biologically perceptible materials. Surface functionalization mediated improved cell-biomaterial interactions led to improved viability, adhesion, and spreading of primary adipose derived mesenchymal stem cells (ADMSCs) as well as improved immunocompatibility. Cytoskeletal architecture assessment under differentiating media containing 10 ng/mL of each basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF) revealed significant actin remodeling with neurite-like projections on the functionalized scaffolds after 14 days. Immunocytochemistry results showed that more than 85% of cells expressed early neuron specific β III tubulin protein on the functionalized scaffolds, whereas glial fibrillary acidic protein (GFAP) expression was limited to approximately 40% of cells. The findings point to the functionalized nanocomposites' potential as a smart scaffold for electrically stimulated neural regeneration, as they are flexible enough to be designed into microchanneled or conduit-like structures that mimic the microstructures and mechanical properties of peripheral nerves.

Lineage reprogramming of human adipose mesenchymal stem cells to immune modulatory i-Heps

Pluripotent stem cell derived-hepatocytes depict fetal -hepatocyte characteristics/maturity and are immunogenic limiting their applications. Attempts have been made to derive hepatocytes from mesenchymal stem cells using developmental cocktails, epigenetic modulators and small molecules. However, achieving a stable terminally differentiated functional state had been a challenge. Inefficient hepatic differentiation could be due to lineage restrictions set during development. Hence a novel lineage reprogramming approach has been utilized to confer competence to adipose-mesenchymal stem cells (ADMSCs) to efficiently respond to hepatogenic cues and achieve a stable functional hepatic state. Lineage reprogramming involved co-transduction of ADMSCs with hepatic endoderm pioneer Transcription factor (TF)-FOXA2, HHEX-a homeobox gene and HNF4α-master TF indispensable for hepatic state maintenance. Lineage priming was evidenced by endogenous HFN4α promoter demethylation and robust responsiveness to minimal hepatic maturation cues. Induced hepatocytes (i-Heps) exhibited mesenchymal-to-epithelial transition and terminal hepatic signatures. Functional characterisation of i-Heps for hepatic drug detoxification systems, xenobiotic uptake/clearance, metabolic status and hepatotropic virus entry validated acquisition of stable hepatic state and junctional maturity Exhaustive analysis of MSC memory in i-Heps indicated loss of MSC-immunophenotype and terminal differentiation to osteogenic/adipogenic lineages. Importantly, i-Heps suppressed phytohemagglutinin-induced T-cell blasts, inhibited allogenic mixed-lymphocyte reactions (MLRs) and secreted immunomodulatory- indoleamine 2,3-dioxygenase in T-cell blast co-cultures akin to native ADMSCs. In a nutshell, the present study identifies a novel cocktail of TFs that reprogram ADMSCs to stable hepatic state. i-Heps exhibit adult hepatocyte functional maturity with robust immune-modulatory abilities rendering suitability for rigorous drug testing, hepatocyte-pathogen interaction studies and transplantation in allogenic settings.

Clinical Application of Induced Hepatocyte-like Cells Produced from Mesenchymal Stromal Cells: A Literature Review

Liver disease is a leading cause of mortality worldwide, resulting in 1.3 million deaths annually. The vast majority of liver disease is caused by metabolic disease (i.e., NASH) and alcohol-induced hepatitis, and to a lesser extent by acute and chronic viral infection. Furthermore, multiple insults to the liver is becoming common due to the prevalence of metabolic and alcohol-related liver diseases. Despite this rising prevalence of liver disease, there are few treatment options: there are treatments for viral hepatitis C and there is vaccination for hepatitis B. Aside from the management of metabolic syndrome, no direct liver therapy has shown clinical efficacy for metabolic liver disease, there is very little for acute alcohol-induced liver disease, and liver transplantation remains the only effective treatment for late-stage liver disease. Traditional pharmacologic interventions have failed to appreciably impact the pathophysiology of alcohol-related liver disease or end-stage liver disease. The difficulties associated with developing liver-specific therapies result from three factors that are common to late-stage liver disease arising from any cause: hepatocyte injury, inflammation, and aberrant tissue healing. Hepatocyte injury results in tissue damage with inflammation, which sensitizes the liver to additional hepatocyte injury and stimulates hepatic stellate cells and aberrant tissue healing responses. In the setting of chronic liver insults, there is progressive scarring, the loss of hepatocyte function, and hemodynamic dysregulation. Regenerative strategies using hepatocyte-like cells that are manufactured from mesenchymal stromal cells may be able to correct this pathophysiology through multiple mechanisms of action. Preclinical studies support their effectiveness and recent clinical studies suggest that cell replacement therapy can be safe and effective in patients with liver disease for whom there is no other option.

Role and Function of Mesenchymal Stem Cells on Fibroblast in Cutaneous Wound Healing

Skin wounds often repair themselves completely over time; however, this is true only for healthy individuals. Although various studies are being conducted to improve wound-healing therapy outcomes, the mechanisms of wound healing and regeneration are not completely understood yet. In recent years, mesenchymal stem cells (MSCs) have been reported to contribute significantly to wound healing and regeneration. Understanding the function of MSCs will help to elucidate the fundamentals of wound healing. MSCs are multipotent stem cells that are used in regenerative medicine for their ability to self-renew and differentiate into bone, fat, and cartilage, with few ethical problems associated with cell harvesting. Additionally, they have anti-inflammatory and immunomodulatory properties and antifibrotic effects via paracrine signaling, and many studies have been conducted to use them to treat graft-versus-host disease, inflammatory bowel disease, and intractable cutaneous wounds. Many substances derived from MSCs are involved in the wound-healing process, and specific cascades and pathways have been elucidated. This review aims to explain the fundamental role of MSCs in wound healing and the effects of MSCs on fibroblasts.

Hepatocyte Differentiation from iPSCs or MSCs in Decellularized Liver Scaffold: Cell–ECM Adhesion, Spatial Distribution, and Hepatocyte Maturation Profile

Mesenchymal stem cells (MSC) and induced pluripotent stem cells (iPSC) have been reported to be able to differentiate to hepatocyte in vitro with varying degree of hepatocyte maturation. A simple method to decellularize liver scaffold has been established by the Department of Histology, Faculty of Medicine, Universitas Indonesia, in SCTE IMERI lab.¹⁵ This study aims to evaluate hepatocyte differentiation from iPSCs compared to MSCs derived in our decellularized liver scaffold. The research stages started with iPSC culture, decellularization, seeding cell culture into the scaffold, and differentiation into hepatocytes for 21 days. Hepatocyte differentiation from iPSCs and MSCs in the scaffolds was characterized using hematoxylin–eosin, Masson Trichrome, and immunohistochemistry staining to determine the fraction of the differentiation area. RNA samples were isolated on days 7 and 21. Expression of albumin, CYP450, and CK-19 genes were analyzed using the qRT-PCR method. Electron microscopy images were obtained by SEM. Immunofluorescence examination was done using HNF4-α and CEBPA markers. The results of this study in hepatocyte-differentiated iPSCs compared with hepatocyte-differentiated MSCs in decellularized liver scaffold showed lower adhesion capacity, single-cell-formation and adhered less abundant, decreased trends of albumin, and lower CYP450 expression. Several factors contribute to this result: lower initial seeding number, which causes only a few iPSCs to attach to certain parts of decellularized liver scaffold, and manual syringe injection for recellularization, which abruptly and unevenly creates pattern of single-cell-formation by hepatocyte-differentiated iPSC in the scaffold. Hepatocyte-differentiated MSCs have the advantage of higher adhesion capacity to collagen fiber decellularized liver scaffold. This leads to positive result: increase trends of albumin and higher CYP450 expression. Hepatocyte maturation is shown by diminishing CK-19, which is more prominent in hepatocyte-differentiated iPSCs in decellularized liver scaffold. Confirmation of mature hepatocyte-differentiated iPSCs in decellularized liver scaffold maturation is positive for HNF4-a and CEBPA. The conclusion of this study is hepatocyte-differentiated iPSCs in decellularized liver scaffold is mature with lower cell–ECM adhesion, spatial cell distribution, albumin, and CYP450 expression than hepatocyte-differentiated MSCs in decellularized liver scaffold.

Tissue Engineering for Tracheal Replacement: Strategies and Challenges

The critical feature in trachea replacement is to provide a hollow cylindrical framework that is laterally stable and longitudinally flexible, facilitating cartilage and epithelial tissue formation. Despite advanced techniques and sources of materials used, most inherent challenges are related to the complexity of its anatomy. Limited blood supply leads to insufficient regenerative capacity for cartilage and epithelium. Natural and synthetic scaffolds, different types of cells, and growth factors are part of tissue engineering approaches with varying outcomes. Pre-vascularization remains one of the crucial factors to expedite the regenerative process in tracheal reconstruction. This review discusses the challenges and strategies used in tracheal tissue engineering, focusing on scaffold implantation in clinical and preclinical studies conducted in recent decades.

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.

Extracellular Vesicles, Stem Cells and the Role of miRNAs in Neurodegeneration

There are different modalities of intercellular communication governed by cellular homeostasis. In this review, we will explore one of these forms of communication called extracellular vesicles (EVs). These vesicles are released by all cells in the body and are heterogeneous in nature. The primary function of EVs is to share information through their cargo consisting of proteins, lipids and nucleic acids (mRNA, miRNA, dsDNA etc.) with other cells, which have a direct consequence on their microenvironment. We will focus on the role of EVs of mesenchymal stem cells (MSCs) in the nervous system and how these participate in intercellular communication to maintain physiological function and provide neuroprotection. However, deregulation of this same communication system could play a role in several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, multiple sclerosis, prion disease and Huntington's disease. The release of EVs from a cell provides crucial information to what is happening inside the cell and thus could be used in diagnostics and therapy. We will discuss and explore new avenues for the clinical applications of using engineered MSC-EVs and their potential therapeutic benefit in treating neurodegenerative diseases.

Application of mesenchymal stem cells derived from human pluripotent stem cells in regenerative medicine

Mesenchymal stem cells (MSCs) represent the most clinically used stem cells in regenerative medicine. However, due to the disadvantages with primary MSCs, such as limited cell proliferative capacity and rarity in the tissues leading to limited MSCs, gradual loss of differentiation during in vitro expansion reducing the efficacy of MSC application, and variation among donors increasing the uncertainty of MSC efficacy, the clinical application of MSCs has been greatly hampered. MSCs derived from human pluripotent stem cells (hPSC-MSCs) can circumvent these problems associated with primary MSCs. Due to the infinite self-renewal of hPSCs and their differentiation potential towards MSCs, hPSC-MSCs are emerging as an attractive alternative for regenerative medicine. This review summarizes the progress on derivation of MSCs from human pluripotent stem cells, disease modelling and drug screening using hPSC-MSCs, and various applications of hPSC-MSCs in regenerative medicine. In the end, the challenges and concerns with hPSC-MSC applications are also discussed.

Characterization of adipose tissue-derived stromal cells of mice with nonalcoholic fatty liver disease and their use for liver repair

Introduction

Freshly isolated uncultured adipose tissue-derived stromal cells (u-ADSCs), containing miscellaneous cells like the relatively abundant mesenchymal stem cells, are attractive for repair and regenerative therapy. However, the detailed characteristics and therapeutic efficacy of u-ADSCs obtained from disease-affected hosts are unknown. We compared the properties of u-ADSCs obtained from wild-type mice and from a mouse model of non-alcoholic steatohepatitis (NASH).

Methods

The NASH model was established by feeding C57BL/6J mice an atherogenic high-fat diet for 4 (NASH (4w)) or 12 weeks (NASH (12w)), followed by the isolation and characterization of u-ADSCs. Wild-type u-ADSCs or NASH-derived u-ADSCs were administered to mice with NASH cirrhosis, followed by analyses of hepatic inflammatory cells, antigen profiles, fibrosis, and gene expression.

Results

Wild-type u-ADSCs and NASH-derived u-ADSCs did not show marked differences in surface antigen profiles. In NASH (4w) u-ADSCs, but not NASH (12w) u-ADSCs, the frequencies of the leukocyte markers CD11b, CD45, and CD44 were elevated; furthermore, we observed an increase in the M1/M2 macrophage ratio only in NASH (12w) u-ADSCs. Only in NASH-4w u-ADSCs, the expression levels cell cycle-related genes were higher than those in u-ADSCs. Wild-type u-ADSCs administered to mice with NASH-related cirrhosis decreased the infiltration of CD11b+, F4/80+, and Gr-1+ inflammatory cells, ameliorated fibrosis, and had a restorative effect on liver tissues, as determined by gene expression profiles and the NAFLD activity score. The therapeutic effects of NASH (4w) u-ADSCs and NASH (12w) u-ADSCs on NASH-related cirrhosis were highly similar to the effect of wild-type u-ADSCs, including reductions in inflammation and fibrosis.

Conclusions

NASH-derived u-ADSCs, similar to wild-type u-ADSCs, are applicable for reparative and regenerative therapy in mice with NASH.

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Uncultured adipose tissue-derived stromal cells (u-ADSCs) in regenerative therapy.

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Nonalcoholic steatohepatitis (NASH) mice model was established.

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We confirmed the efficacy of u-ADSCs for treatment of cirrhotic mice.

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We studied the NASH mouse model-derived u-ADSCs for treatment of cirrhotic mice.

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NASH-u-ADSCs and wild-type u-ADSCs are anti-inflammatory and effective for cirrhosis.

The role of mesenchymal stem cells in liver injury

Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have potential therapeutic value, because these have high self-renewal ability, are capable of multipotent differentiation, and have low immunogenicity. Furthermore, MSCs have the potential to differentiate into hepatocytes, and the therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. Moreover, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis, and enhance liver functionality. This article is protected by copyright. All rights reserved.

Chemically Defined Conditions Mediate an Efficient Induction of Dental Pulp Pluripotent-Like Stem Cells into Hepatocyte-Like Cells

Liver diseases are major causes of morbidity and mortality. Dental pulp pluripotent-like stem cells (DPPSCs) are of a considerable promise in tissue engineering and regenerative medicine as a new source of tissue-specific cells; therefore, this study is aimed at demonstrating their ability to generate functional hepatocyte-like cells in vitro. Cells were differentiated on a collagen scaffold in serum-free media supplemented with growth factors and cytokines to recapitulate liver development. At day 5, the differentiated DPPSC cells expressed the endodermal markers FOXA1 and FOXA2. Then, the cells were derived into the hepatic lineage generating hepatocyte-like cells. In addition to the associated morphological changes, the cells expressed the hepatic genes HNF6 and AFP. The terminally differentiated hepatocyte-like cells expressed the liver functional proteins albumin and CYP3A4. In this study, we report an efficient serum-free protocol to differentiate DPPSCs into functional hepatocyte-like cells. Our approach promotes the use of DPPSCs as a new source of adult stem cells for prospective use in liver regenerative medicine.

Functional hit 1 (FH1)-based rapid and efficient generation of functional hepatocytes from human mesenchymal stem cells: a novel strategy for hepatic differentiation

Background

Because the liver is central to the physiology of the body, primary hepatocytes are widely used in liver pathology and physiological research, such as liver drug screening, bioartificial liver support system, and cell therapy for liver diseases. However, the source of primary hepatocytes is limited. We describe a novel non-transgenic protocol that facilitates the rapid generation of hepatocyte-like cells from human umbilical cord-derived mesenchymal stem cells (hUC-MSCs), providing a new source of functional hepatocytes.

Methods

In this study, we used hUC-MSCs and human induced pluripotent cells (iPSCs) derived mesenchymal stem cells (iMSCs) to investigate the new induction strategy. Passage 3 MSCs were induced into hepatocyte-like cells using small-molecule compounds combined with cell factors in vitro. Functional hit 1 (FH1), a promising small molecule compound was achieved to replace HGF in the hepatocyte maturation stage to induce the hepatocyte-like cells differentiation.

Results

We rapidly induced hUC-MSCs and human iMSCs into hepatocyte-like cells within 10 days in vitro, and the cells were morphologically similarly to both hepatocytes derived from the hepatocyte growth factor (HGF)-based method and the primary hepatocytes. They expressed mature hepatocyte special genes and achieved functions such as glycogen storage, albumin expression, urea secretion, cytochrome P450 activity, Low-density lipoprotein (LDL) uptake, and indocyanine green (ICG) uptake.

Conclusions

We successfully established a small-molecule protocol without using HGF to differentiate MSCs into hepatocyte-like cells, which provides a rapid and cost-effective platform for in vitro studies of liver disease.

Exosomes secreted from human umbilical cord mesenchymal stem cells promote pancreatic ductal adenocarcinoma growth by transferring miR-100-5p

PURPOSE

Although human umbilical cord mesenchymal stem cells (hucMSCs) can contribute to the growth of tumors, including pancreatic ductal adenocarcinoma (PDAC), however, little is known about the exact mechanisms by which the exosomes secreted from hucMSCs (hucMSCs-exo) have an oncogenic effect on the physiopathology of PDAC. The effects of hucMSCs on tumor development are attributed to hucMSCs-exo, which deliver unique proteins and miRNAs to cancer cells.

METHODS

HucMSCs and exosomes were isolated and confirmed via transmission electron microscopy, nanoparticle tracking analysis and western blot. The nude mice were inoculated subcutaneously on both flanks with human pancreatic cancer Panc-1 cells (1 × 10⁶), and hucMSCs-exo were directly administered via intratumoral injection once a day for three days each week. Cell proliferation assays were performed using a Cell Counting Kit-8 assay and the cell invasion assay was performed using Transwell assay. The miRNA data were predicted and analyzed by miRanda software. The analysis of the target genes of the miRNAs was proformed with the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases.

RESULTS

Firstly, we observed that hucMSCs-exo promoted Panc-1 and BxPC3 cell growth by increasing proliferation and migration in vitro. Secondly, in a xenograft tumor model, hucMSCs-exo increased the growth of Panc-1 cells. Thirdly, high-throughput sequencing of hucMSCs-exo showed that hsa-miR-148a-3p, hsa-miR-100-5p, hsa-miR-143-3p, hsa-miR-21-5p and hsa-miR-92a-3p were highly expressed. For the five identified miRNAs, 1308 target genes were predicted by miRanda software. From the GO and KEGG analyses of the target genes of the identified miRNAs, it was found that the main GO function was the regulation of cellular glucuronidation, and the main KEGG metabolic pathway involved the metabolism of ascorbic acid and aldehyde acid. These processes are related to the occurrence and development of pancreatic cancer. Finally, we observed that miR-100-5p promoted Panc-1 and BxPC3 cell growth in vitro and in vivo.

CONCLUSION

Here, by utilizing exosomes secreted from hucMSCs, we systematically investigated the effects of hucMSCs-exo on PDAC growth in vitro and in vivo for the first time. Building on these results, we provided new insights into the role of hucMSCs-exo in the PDAC growth and revealed the attractive communication between hucMSCs and PDAC cells that occurs through MSCs-exosomes-miRNAs.

Recommendations for Nomenclature and Definition Of Cell Products Intended for Human Cardiovascular Use

Exogenous cell-based therapy has emerged as a promising new strategy to facilitate repair of hearts damaged by acute or chronic injury. However, the field of cell-based therapy is handicapped by the lack of standardized definitions and terminology, making comparisons across studies challenging. Even the term "stem cell therapy" is misleading because only a small percentage of cells derived from adult bone marrow, peripheral blood, or adipose tissue meets the accepted hematopoietic or developmental definition of stem cells. Furthermore, cells (stem or otherwise) are dynamic biological products, meaning that their surface marker expression, phenotypic and functional characteristics, and the products they secrete in response to their microenvironment can change. It is also important to point out that most surface markers are seldom specific for a cell type. In this article, we discuss the lack of consistency in the descriptive terminology used in cell-based therapies and offer guidelines aimed at standardizing nomenclature and definitions to improve communication among investigators and the general public.

Progress and Challenges in the Use of a Liver-on-a-Chip for Hepatotropic Infectious Diseases

The liver is a target organ of life-threatening pathogens and prominently contributes to the variation in drug responses and drug-induced liver injury among patients. Currently available drugs significantly decrease the morbidity and mortality of liver-dwelling pathogens worldwide; however, emerging clinical evidence reveals the importance of host factors in the design of safe and effective therapies for individuals, known as personalized medicine. Given the primary adherence of cells in conventional two-dimensional culture, the use of these one-size-fit-to-all models in preclinical drug development can lead to substantial failures in assessing therapeutic safety and efficacy. Advances in stem cell biology, bioengineering and material sciences allow us to develop a more physiologically relevant model that is capable of recapitulating the human liver. This report reviews the current use of liver-on-a-chip models of hepatotropic infectious diseases in the context of precision medicine including hepatitis virus and malaria parasites, assesses patient-specific responses to antiviral drugs, and designs personalized therapeutic treatments to address the need for a personalized liver-like model. Second, most organs-on-chips lack a monitoring system for cell functions in real time; thus, the review discusses recent advances and challenges in combining liver-on-a-chip technology with biosensors for assessing hepatocyte viability and functions. Prospectively, the biosensor-integrated liver-on-a-chip device would provide novel biological insights that could accelerate the development of novel therapeutic compounds.

Genetically Modified Mesenchymal Stromal/Stem Cells: Application in Critical Illness

Critical illnesses including sepsis, acute respiratory distress syndromes, ischemic cardiovascular disorders and acute organ injuries are associated with high mortality, morbidity as well as significant health care system expenses. While these diverse conditions require different specific therapeutic approaches, mesenchymal stem/stromal cell (MSCs) are multipotent cells capable of self-renewal, tri-lineage differentiation with a broad range regenerative and immunomodulatory activities, making them attractive for the treatment of critical illness. The therapeutic effects of MSCs have been extensively investigated in several pre-clinical models of critical illness as well as in phase I and II clinical cell therapy trials with mixed results. Whilst these studies have demonstrated the therapeutic potential for MSC therapy in critical illness, optimization for clinical use is an ongoing challenge. MSCs can be readily genetically modified by application of different techniques and tools leading to overexpress or inhibit genes related to their immunomodulatory or regenerative functions. Here we will review recent approaches designed to enhance the therapeutic potential of MSCs with an emphasis on the technology used to generate genetically modified cells, target genes, target diseases and the implication of genetically modified MSCs in cell therapy for critical illness.

Mesenchymal stem cells therapy for acute liver failure: Recent advances and future perspectives

Acute liver failure (ALF) is a life-threatening disease characterized by the rapid development of hepatocyte death and a systemic inflammatory response, which leads to high mortality. Despite the prevention of ALF complications, therapeutic effectiveness remains limited because of the rapid disease progression. Thus, there is a need to explore various therapeutic approaches. Currently, the only effective treatment is liver transplantation; However, the lack of donors, surgical complications, immunosuppression, and high medical costs limit its clinical application. Recently, mesenchymal stem cells (MSCs) have been found to exert hepatoprotective effects in ALF through suppression of inflammation, immunoregulation, promotion of mitosis, anti-apoptosis effects, and alleviation of the metabolic and oxidative stress imbalance. In this review, we summarize the advantages and disadvantages of MSCs from different sources and their molecular mechanisms in ALF treatment, along with future perspectives that may provide guidance to improve the current status of MSCs therapy for ALF.

Hepatic patch by stacking patient-specific liver progenitor cell sheets formed on multiscale electrospun fibers promotes regenerative therapy for liver injury

Recently, use of cell sheets with bio-applicable fabrication materials for transplantation has been an attractive approach for the treatment of patients with liver failure. However, renewable and scalable cell sources for engineered tissue patches remain limited. We previously reported a new type of proliferating bipotent human chemically derived hepatic progenitor cells (hCdHs) developed by small molecule-mediated reprogramming. Here, we developed a patient-specific hepatic cell sheet constructed from liver biopsy-derived hCdHs on a multiscale fibrous scaffold by combining electrospinning and three-dimensional printing. Analysis of biomaterial composition revealed that the high-density electrospun sheet was superior in increasing the functional properties of hCdHs. Furthermore, the hepatic patch assembled by multilayer stacking with alternate cell sheets of hCdHs and human umbilical vein endothelial cells (HUVECs) recapitulated a liver tissue-like structure, with histological and morphological shape and size similar to those of primary human hepatocytes, and exhibited a significant increase in hepatic functions such as albumin secretion and activity of cytochrome P450 during in vitro hepatic differentiation compared with that in hCdH cells cultured in a two-dimensional monolayer. Interestingly, in the hepatic patch, the induction of functional hepatocytes was associated with both the electrospun fibrous-facilitated oncostatin M signaling and selective activation of AKT signaling by HUVECs. Notably, upon transplantation into a mouse model of therapeutic liver repopulation, the hepatic patch effectively repopulated the damaged parenchyma and induced the restoration of liver function with healthy morphology in the lobe and an improved survival rate (>70%) in mice. Overall, these results suggested that liver biopsy-derived hCdHs can be an efficient alternative source for developing hepatic cell sheets and patches with potential clinical applications in tissue engineering to advance liver regeneration.

Priming human adipose-derived mesenchymal stem cells for corneal surface regeneration

Limbal stem cells (LSC) maintain the transparency of the corneal epithelium. Chemical burns lead the loss of LSC inducing an up-regulation of pro-inflammatory and pro-angiogenic factors, triggering corneal neovascularization and blindness. Adipose tissue-derived mesenchymal stem cells (AT-MSC) have shown promise in animal models to treat LSC deficiency (LSCD), but there are not studies showing their efficacy when primed with different media before transplantation. We cultured AT-MSC with standard medium and media used to culture LSC for clinical application. We demonstrated that different media changed the AT-MSC paracrine secretion showing different paracrine effector functions in an in vivo model of chemical burn and in response to a novel in vitro model of corneal inflammation by alkali induction. Treatment of LSCD with AT-MSC changed the angiogenic and inflammatory cytokine profile of mice corneas. AT-MSC cultured with the medium that improved their cytokine secretion, enhanced the anti-angiogenic and anti-inflammatory profile of the treated corneas. Those corneas also presented better outcome in terms of corneal transparency, neovascularization and histologic reconstruction. Priming human AT-MSC with LSC specific medium can potentiate their ability to improve corneal wound healing, decrease neovascularization and inflammation modulating paracrine effector functions in an in vivo optimized rat model of LSCD.

Adenine base editing and prime editing of chemically derived hepatic progenitors rescue genetic liver disease

DNA base editors and prime editing technology enable therapeutic in situ correction of disease-causing alleles. These techniques could have broad applications for ex vivo editing of cells prior to transplantation in a range of diseases, but it is critical that the target population is efficiently modified and engrafts into the host. Chemically derived hepatic progenitors (CdHs) are a multipotent population capable of robust engraftment and hepatocyte differentiation. Here we reprogrammed hepatocytes from a mouse model of hereditary tyrosinemia type 1 (HT1) into expandable CdHs and successfully corrected the disease-causing mutation using both adenine base editors (ABEs) and prime editors (PEs). ABE- and PE-corrected CdHs repopulated the liver with fumarylacetoacetate hydrolase-positive cells and dramatically increased survival of mutant HT1 mice. These results demonstrate the feasibility of precise gene editing in transplantable cell populations for potential treatment of genetic liver disease.