Progress in mesenchymal stem cell-based therapy for acute liver failure

Human umbilical cord mesenchymal stem cells alleviate fatty liver ischemia-reperfusion injury by activating autophagy through upregulation of IFNγ

Liver ischemia-reperfusion injury (IRI) is an important factor affecting the prognosis of liver transplantation, and extended criteria donors (e.g., steatosis donor livers) are considered to be more sensitive to ischemia-reperfusion injury in liver transplantation. Currently, the application of human umbilical cord mesenchymal stem cells (hMSCs) has great promise in the treatment of various injuries in the liver. This study aimed to investigate the therapeutic role and mechanism of hMSCs in fatty liver IRI. After more than 8 weeks of high-fat chow feeding, we constructed a fatty liver mouse model and established ischemic injury of about 70% of the liver. Six hours after IRI, liver injury was significantly alleviated in hMSCs-treated mice, and the expression levels of liver enzyme, inflammatory factor TNF-α, and apoptotic proteins were significantly lower than those of the control group, which were also significant in pathological sections. Transcriptomics analysis showed that IFNγ was significantly upregulated in the hMSCs group. Mechanistically, IFNγ, which activates the MAPK pathway, is a potent agonist that promotes the occurrence of autophagy in hepatocytes to exert a protective function, which was confirmed by in vitro experiments. In summary, hMSCs treatment could slow down IRI in fatty liver by activating autophagy through upregulation of IFNγ, and this effect was partly direct.

Stem Cell-Based Strategies: The Future Direction of Bioartificial Liver Development

Acute liver failure (ALF) results from severe liver damage or end-stage liver disease. It is extremely fatal and causes serious health and economic burdens worldwide. Once ALF occurs, liver transplantation (LT) is the only definitive and recommended treatment; however, LT is limited by the scarcity of liver grafts. Consequently, the clinical use of bioartificial liver (BAL) has been proposed as a treatment strategy for ALF. Human primary hepatocytes are an ideal cell source for these methods. However, their high demand and superior viability prevent their widespread use. Hence, finding alternatives that meet the seed cell quality and quantity requirements is imperative. Stem cells with self-renewing, immunogenic, and differentiative capacities are potential cell sources. MSCs and its secretomes encompass a spectrum of beneficial properties, such as anti-inflammatory, immunomodulatory, anti-ROS (reactive oxygen species), anti-apoptotic, pro-metabolomic, anti-fibrogenesis, and pro-regenerative attributes. This review focused on the recent status and future directions of stem cell-based strategies in BAL for ALF. Additionally, we discussed the opportunities and challenges associated with promoting such strategies for clinical applications.

Organ Frame Elements or Free Intercellular Gel-Like Matrix as Necessary Conditions for Building Organ Structures during Regeneration

Over the past decades, an unimaginably large number of attempts have been made to restore the structure of mammalian organs after injury by introducing stem cells into them. However, this procedure does not lead to full recovery. At the same time, it is known that complete regeneration (restitution without fibrosis) is possible in organs with proliferating parenchymal cells. An analysis of such models allows to conclude that the most important condition for the repair of histological structures of an organ (in the presence of stem cells) is preservation of the collagen frame structures in it, which serve as "guide rails" for proliferating and differentiating cells. An alternative condition for complete reconstruction of organ structures is the presence of a free "morphogenetic space" containing a gel-like matrix of the embryonic-type connective tissue, which exists during embryonal development of organs in mammals or during complete regeneration in amphibians. Approaches aimed at preserving frame structures or creating a "morphogenetic space" could radically improve the results of organ regeneration using both local and exogenous stem cells.

Hypoxia and inflammatory factor preconditioning enhances the immunosuppressive properties of human umbilical cord mesenchymal stem cells

BACKGROUND

Mesenchymal stem cells (MSCs) have great potential for the treatment of various immune diseases due to their unique immunomodulatory properties. However, MSCs exposed to the harsh inflammatory environment of damaged tissue after intravenous transplantation cannot exert their biological effects, and therefore, their therapeutic efficacy is reduced. In this challenging context, an in vitro preconditioning method is necessary for the development of MSC-based therapies with increased immunomodulatory capacity and transplantation efficacy.

AIM

To determine whether hypoxia and inflammatory factor preconditioning increases the immunosuppressive properties of MSCs without affecting their biological characteristics.

METHODS

Umbilical cord MSCs (UC-MSCs) were pretreated with hypoxia (2% O2) exposure and inflammatory factors (interleukin-1β, tumor necrosis factor-α, interferon-γ) for 24 h. Flow cytometry, polymerase chain reaction, enzyme-linked immunosorbent assay and other experimental methods were used to evaluate the biological characteristics of pretreated UC-MSCs and to determine whether pretreatment affected the immunosuppressive ability of UC-MSCs in coculture with immune cells.

RESULTS

Pretreatment with hypoxia and inflammatory factors caused UC-MSCs to be elongated but did not affect their viability, proliferation or size. In addition, pretreatment significantly decreased the expression of coagulation-related tissue factors but did not affect the expression of other surface markers. Similarly, mitochondrial function and integrity were retained. Although pretreatment promoted UC-MSC apoptosis and senescence, it increased the expression of genes and proteins related to immune regulation. Pretreatment increased peripheral blood mononuclear cell and natural killer (NK) cell proliferation rates and inhibited NK cell-induced toxicity to varying degrees.

CONCLUSION

In summary, hypoxia and inflammatory factor preconditioning led to higher immunosuppressive effects of MSCs without damaging their biological characteristics.

MFGE-8 identified in fetal mesenchymal-stromal-cell-derived exosomes ameliorates acute hepatic failure pathology

Liver transplantation is the gold-standard therapy for acute hepatic failure (AHF) with limitations related to organ shortage and life-long immunosuppressive therapy. Cell therapy emerges as a promising alternative to transplantation. We have previously shown that IL-10 and Annexin-A1 released by amniotic fluid human mesenchymal stromal cells (AF-MSCs) and their hepatocyte progenitor-like (HPL) or hepatocyte-like (HPL) cells induce liver repair and downregulate systemic inflammation in a CCl4-AHF mouse model. Herein, we demonstrate that exosomes (EXO) derived from these cells improve liver phenotype in CCl4-induced mice and promote oval cell proliferation. LC-MS/MS proteomic analysis identified MEFG-8 in EXO cargo that facilitates rescue of AHF by suppressing PI3K signaling. Administration of recombinant MFGE-8 protein also reduced liver damage in CCl4-induced mice. Clinically, MEFG-8 expression was decreased in liver biopsies from AHF patients. Collectively, our study provides proof-of-concept for an innovative, cell-free, less immunogenic, and non-toxic alternative strategy for AHF.

Efficacy and safety of mesenchymal stem cell therapy in liver cirrhosis: a systematic review and meta-analysis

AIM

Although the efficacy and safety of mesenchymal stem cell therapy for liver cirrhosis have been demonstrated in several studies. Clinical cases of mesenchymal stem cell therapy for patients with liver cirrhosis are limited and these studies lack the consistency of treatment effects. This article aimed to systematically investigate the efficacy and safety of mesenchymal stem cells in the treatment of liver cirrhosis.

METHOD

The data source included PubMed/Medline, Web of Science, EMBASE, and Cochrane Library, from inception to May 2023. Literature was screened by the PICOS principle, followed by literature quality evaluation to assess the risk of bias. Finally, the data from each study's outcome indicators were extracted for a combined analysis. Outcome indicators of the assessment included liver functions and adverse events. Statistical analysis was performed using Review Manager 5.4.

RESULTS

A total of 11 clinical trials met the selection criteria. The pooled analysis' findings demonstrated that both primary and secondary indicators had improved. Compared to the control group, infusion of mesenchymal stem cells significantly increased ALB levels in 2 weeks, 1 month, 3 months, and 6 months, and significantly decreased MELD score in 1 month, 2 months, and 6 months, according to a subgroup analysis using a random-effects model. Additionally, the hepatic arterial injection favored improvements in MELD score and ALB levels. Importantly, none of the included studies indicated any severe adverse effects.

CONCLUSION

The results showed that mesenchymal stem cell was effective and safe in the treatment of liver cirrhosis, improving liver function (such as a decrease in MELD score and an increase in ALB levels) in patients with liver cirrhosis and exerting protective effects on complications of liver cirrhosis and the incidence of hepatocellular carcinoma. Although the results of the subgroup analysis were informative for the selection of mesenchymal stem cells for clinical treatment, a large number of high-quality randomized controlled trials validations are still needed.

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.

Breaking the graft-versus-host-disease barrier: Mesenchymal stromal/stem cells as precision healers

Mesenchymal Stromal/Stem Cells (MSCs) are multipotent, non-hematopoietic progenitor cells with a wide range of immune modulation and regenerative potential which qualify them as a potential component of cell-based therapy for various autoimmune/chronic inflammatory ailments. Their immunomodulatory properties include the secretion of immunosuppressive cytokines, the ability to suppress T-cell activation and differentiation, and the induction of regulatory T-cells. Considering this and our interest, we here discuss the significance of MSC for the management of Graft-versus-Host-Disease (GvHD), one of the autoimmune manifestations in human. In pre-clinical models, MSCs have been shown to reduce the severity of GvHD symptoms, including skin and gut damage, which are the most common and debilitating manifestations of this disease. While initial clinical studies of MSCs in GvHD cases were promising, the results were variable in randomized studies. So, further studies are warranted to fully understand their potential benefits, safety profile, and optimal dosing regimens. Owing to these inevitable issues, here we discuss various mechanisms, and how MSCs can be employed in managing GvHD, as a cellular therapeutic approach for this disease.

Recent advances in pre-conditioned mesenchymal stem/stromal cell (MSCs) therapy in organ failure; a comprehensive review of preclinical studies

Mesenchymal stem/stromal cells (MSCs)-based therapy brings the reassuring capability to regenerative medicine through their self-renewal and multilineage potency. Also, they secret a diversity of mediators, which are complicated in moderation of deregulated immune responses, and yielding angiogenesis in vivo. Nonetheless, MSCs may lose biological performance after procurement and prolonged expansion in vitro. Also, following transplantation and migration to target tissue, they encounter a harsh milieu accompanied by death signals because of the lack of proper tensegrity structure between the cells and matrix. Accordingly, pre-conditioning of MSCs is strongly suggested to upgrade their performances in vivo, leading to more favored transplantation efficacy in regenerative medicine. Indeed, MSCs ex vivo pre-conditioning by hypoxia, inflammatory stimulus, or other factors/conditions may stimulate their survival, proliferation, migration, exosome secretion, and pro-angiogenic and anti-inflammatory characteristics in vivo. In this review, we deliver an overview of the pre-conditioning methods that are considered a strategy for improving the therapeutic efficacy of MSCs in organ failures, in particular, renal, heart, lung, and liver.

Current Status and Prospect of Delivery Vehicle Based on Mesenchymal Stem Cell-Derived Exosomes in Liver Diseases

With the improvement of the average life expectancy and increasing incidence of obesity, the burden of liver disease is increasing. Liver disease is a serious threat to human health. Currently, liver transplantation is the only effective treatment for end-stage liver disease. However, liver transplantation still faces unavoidable difficulties. Mesenchymal stem cells (MSCs) can be used as an alternative therapy for liver disease, especially liver cirrhosis, liver failure, and liver transplantation complications. However, MSCs may have potential tumorigenic effects. Exosomes derived from MSCs (MSC-Exos), as the important intercellular communication mode of MSCs, contain various proteins, nucleic acids, and DNA. MSC-Exos can be used as a delivery system to treat liver diseases through immune regulation, apoptosis inhibition, regeneration promotion, drug delivery, and other ways. Good histocompatibility and material exchangeability make MSC-Exos a new treatment for liver diseases. This review summarizes the latest research on MSC-Exos as delivery vehicles in different liver diseases, including liver injury, liver failure, liver fibrosis, hepatocellular carcinoma (HCC), and ischemia and reperfusion injury. In addition, we discuss the advantages, disadvantages, and clinical application prospects of MSC-Exos-based delivery vectors in the treatment of liver diseases.

Magnetic Nanostructures and Stem Cells for Regenerative Medicine, Application in Liver Diseases

The term "liver disease" refers to any hepatic condition that leads to tissue damage or altered hepatic function and can be induced by virus infections, autoimmunity, inherited genetic mutations, high consumption of alcohol or drugs, fat accumulation, and cancer. Some types of liver diseases are becoming more frequent worldwide. This can be related to increasing rates of obesity in developed countries, diet changes, higher alcohol intake, and even the coronavirus disease 2019 (COVID-19) pandemic was associated with increased liver disease-related deaths. Although the liver can regenerate, in cases of chronic damage or extensive fibrosis, the recovery of tissue mass is impossible, and a liver transplant is indicated. Because of reduced organ availability, it is necessary to search for alternative bioengineered solutions aiming for a cure or increased life expectancy while a transplant is not possible. Therefore, several groups were studying the possibility of stem cells transplantation as a therapeutic alternative since it is a promising strategy in regenerative medicine for treating various diseases. At the same time, nanotechnological advances can contribute to specifically targeting transplanted cells to injured sites using magnetic nanoparticles. In this review, we summarize multiple magnetic nanostructure-based strategies that are promising for treating liver diseases.

Bone marrow mesenchymal stem cell-derived small extracellular vesicles promote liver regeneration via miR-20a-5p/PTEN

Balancing hepatocyte death and proliferation is key to non-transplantation treatments for acute liver failure (ALF), which has a high short-term mortality rate. Small extracellular vesicles (sEVs) may act as mediators in the repair of damaged liver tissue by mesenchymal stem cells (MSCs). We aimed to investigate the efficacy of human bone marrow MSC-derived sEVs (BMSC-sEVs) in treating mice with ALF and the molecular mechanisms involved in regulating hepatocyte proliferation and apoptosis. Small EVs and sEV-free BMSC concentrated medium were injected into mice with LPS/D-GalN-induced ALF to assess survival, changes in serology, liver pathology, and apoptosis and proliferation in different phases. The results were further verified in vitro in L-02 cells with hydrogen peroxide injury. BMSC-sEV-treated mice with ALF had higher 24 h survival rates and more significant reductions in liver injury than mice treated with sEV-free concentrated medium. BMSC-sEVs reduced hepatocyte apoptosis and promoted cell proliferation by upregulating miR-20a-5p, which targeted the PTEN/AKT signaling pathway. Additionally, BMSC-sEVs upregulated the mir-20a precursor in hepatocytes. The application of BMSC-sEVs showed a positive impact by preventing the development of ALF, and may serve as a promising strategy for promoting ALF liver regeneration. miR-20a-5p plays an important role in liver protection from ALF by BMSC-sEVs.

Easy-to-Assembly System for Decellularization and Recellularization of Liver Grafts in a Bioreactor

Decellularization of organs creates an acellular scaffold, ideal for being repopulated by cells. In this work, a low-cost perfusion system was created to be used in the process of liver decellularization and as a bioreactor after recellularization. It consists of a glass chamber to house the organ coupled to a peristaltic pump to promote liquid flow through the organ vascular tree. The rats' liver decellularization was made with a solution of sodium dodecyl sulfate. The recellularization was made with 10⁸ mesenchymal stromal/stem cells and cultivated for seven days. The decellularized matrices showed an absence of DNA while preserving the collagen and glycosaminoglycans quantities, confirming the efficiency of the process. The functional analyses showed a rise in lactate dehydrogenase levels occurring in the first days of the cultivation, suggesting that there is cell death in this period, which stabilized on the seventh day. Histological analysis showed conservation of the collagen web and some groups of cells next to the vessels. It was possible to establish a system for decellularization and a bioreactor to use for the recellularization method. It is easy to assemble, can be ready to use in little time and be easily sterilized.

Establishing an hTERT-driven immortalized umbilical cord-derived mesenchymal stem cell line and its therapeutic application in mice with liver failure

Acute liver failure (ALF) is characterized by rapid liver cell destruction. It is a multi-etiological and fulminant complication with a clinical mortality of over 80%. Therapy using mesenchymal stem cells (MSCs) or MSCs-derived exosomes can alleviate acute liver injury, which has been demonstrated in animal experiments and clinical application. However, similar to other stem cells, different cell sources, poor stability, cell senescence and other factors limit the clinical application of MSCs. To achieve mass production and quality control on stem cells and their exosomes, transfecting umbilical cord mesenchymal stem cell (UCMSC) with lentivirus overexpressing human telomerase reverse transcriptase (hTERT) gene, the hTERT-UCMSC was constructed as an immortalized MSC cell line. Compared with the primary UCMSC (P3) and immortalized cell line hTERT-UCMSC at early passage (P10), the hTERT-UCMSC retained the key morphological and physiological characteristics of UCMSC at the 35th passage (P35), and showed no signs of carcinogenicity and toxic effect in mice. There was no difference in either exosome production or characteristics of exosomes among cultures from P3 primary cells, P10 and P35 immortalized hTERT-UCMSCs. Inoculation of either hTERT-UCMSC (P35) or its exosomes improved the survival rate and liver function of ALF mice induced by thioacetamide (TAA). Our findings suggest that this immortalized cell line can maintain its characteristics in long-term culture. Inoculation of hTERT-UCMSC and its exosomes could potentially be used in clinics for the treatment of liver failure in the future.

HNF4α overexpression enhances the therapeutic potential of umbilical cord mesenchymal stem/stromal cells in mice with acute liver failure

Human umbilical cord mesenchymal stem/stromal cells (hUMSCs) hold promise for treating acute liver failure (ALF). Here, we investigated the therapeutic effect of hUMSCs overexpressing hepatocyte nuclear factor 4α (HNF4α), a transcription factor important for maintaining hepatocyte identity and hepatic functions, in ALF, compared with hUMSCs without overexpression of HNF4α (CON-hUMSCs). The cells were administered into mice via the tail vein for 24 h before exposure to lipopolysaccharide/d-galactosamine (LPS/d-GalN) for 6 h by intraperitoneal injection. HNF4α-hUMSCs ameliorated liver injury in ALF better than CON-hUMSCs. The overexpression of HNF4α enhanced the transcription of interleukin (IL)-10 and promoted M2 macrophage polarization through the IL-10/signal transducer and activator of transcription 3 (STAT3) pathway. HNF4α-hUMSCs could exert a more pronounced therapeutic effect on ALF than CON-hUMSCs, providing a novel therapy for ALF.

Mesenchymal stem cell-based therapy as a new therapeutic approach for acute inflammation

Acute inflammatory diseases such as acute colitis, kidney injury, liver failure, lung injury, myocardial infarction, pancreatitis, septic shock, and spinal cord injury are significant causes of death worldwide. Despite advances in the understanding of its pathophysiology, there are many restrictions in the treatment of these diseases, and new therapeutic approaches are required. Mesenchymal stem cell-based therapy due to immunomodulatory and regenerative properties is a promising candidate for acute inflammatory disease management. Based on preclinical results, mesenchymal stem cells and their-derived secretome improved immunological and clinical parameters. Furthermore, many clinical trials of acute kidney, liver, lung, myocardial, and spinal cord injury have yielded promising results. In this review, we try to provide a comprehensive view of mesenchymal stem cell-based therapy in acute inflammatory diseases as a new treatment approach.

Therapeutic effects of mesenchymal stem cells-conditioned medium derived from suspension cultivation or silymarin on liver failure mice

BACKGROUND

Common treatments of liver disease failed to meet all the needs in this important medical field. It results in an urgent need for proper some new adjuvant therapies. Mesenchymal stem cells (MSCs) and their derivatives are promising tools in this regard. We aimed to compare the Silymarin, as traditional treatment with mesenchymal stem cell conditioned medium (MSC-CM), as a novel strategy, both with therapeutic potentialities in term of liver failure (LF) treatment.

METHODS AND RESULTS

Mice models with liver failure were induced with CCl₄ and were treated in the groups as follows: normal mice receiving DMEM-LG medium as control, LF-mice receiving DMEM-LG medium as sham, LF-mice receiving Silymarin as LF-SM, and LF-mice receiving MSC sphere CM as LF-MSC-CM. Biochemical, histopathological, molecular and protein level parameters were evaluated using blood and liver samples. Liver enzymes, MicroRNA-122 values as well as necrotic score were significantly lower in the LF-SM and LF-MSC-CM groups compared to sham. LF-SM showed significantly higher level of total antioxidant capacity and malondialdehyde than that of LF-MSC-CM groups. Sph-MSC-CM not only induced more down-regulated expression of fibrinogen-like protein 1 and receptor interacting protein kinases1 but also led to higher expression level of keratinocyte growth factor. LF-MSC-CM showed less mortality rate compared to other groups.

CONCLUSIONS

Hepato-protective potentialities of Sph-MSC-CM are comparable to those of Silymarin. More inhibition of necroptosis/ necrosis and inflammation might result in rapid liver repair in case of MSC-CM administration.

Bone-Marrow-Derived Mesenchymal Stem Cells, Their Conditioned Media, and Olive Leaf Extract Protect against Cisplatin-Induced Toxicity by Alleviating Oxidative Stress, Inflammation, and Apoptosis in Rats

BACKGROUND

Hepatic and renal damage is a cisplatin (Cis)-induced deleterious effect that is a major limiting factor in clinical chemotherapy.

OBJECTIVES

The current study was designed to investigate the influence of pretreatment with olive leaf extract (OLE), bone-marrow-derived mesenchymal stem cells (BM-MSC), and their conditioned media (CM-MSC) against genotoxicity, nephrotoxicity, hepatotoxicity, and immunotoxicity induced by cisplatin in rats.

METHODS

The rats were randomly divided into six groups (six rats each) as follows: Control; OLE group, treated with OLE; Cis group, treated with a single intraperitoneal dose of Cis (7 mg/kg bw); Cis + OLE group, treated with OLE and cisplatin; Cis + CM-MSC group, treated with BM-MSC conditioned media and Cis; and Cis + MSC group, treated with BM-MSC in addition to Cis.

RESULTS

Cis resulted in a significant deterioration in hepatic and renal functions and histological structures. Furthermore, it increased inflammatory markers (TNF-α, IL-6, and IL-1β) and malondialdehyde (MDA) levels and decreased glutathione (GSH) content, total antioxidant capacity (TAC), catalase (CAT), and superoxide dismutase (SOD) activity in hepatic and renal tissues. Furthermore, apoptosis was evident in rat tissues. A significant increase in serum 8-hydroxy-2-deoxyguanosine (8-OH-dG), nitric oxide (NO) and lactate dehydrogenase (LDH), and a decrease in lysozyme activity were detected in Cis-treated rats. OLE, CM-MSC, and BM-MSC have significantly ameliorated Cis-induced deterioration in hepatic and renal structure and function and improved oxidative stress and inflammatory markers, with preference to BM-MSC. Moreover, apoptosis was significantly inhibited, evident from the decreased expression of Bax and caspase-3 genes and upregulation of Bcl-2 proteins in protective groups as compared to Cis group.

CONCLUSIONS

These findings indicate that BM-MSC, CM-MSC, and OLE have beneficial effects in ameliorating cisplatin-induced oxidative stress, inflammation, and apoptosis in the hepatotoxicity, nephrotoxicity, immunotoxicity, and genotoxicity in a rat model.

Bioinspired All-in-One Three-Dimensional Dynamic CellMatrix Improves the Manufacture of Therapeutically Qualified Cells for Cell Therapy

Despite the great promise, cell therapy still faces practical challenges because of the scarcity of a reliable cell source. Herein, a bioinspired 3D dynamic culture system (CellMatrix) with rational structure, composite and function, was developed for improving cell supply. CellMatrix was composed of unique core-shell fibers with a core of black phosphorus-incorporated fibroin and a shell of sericin, which together formed a 3D silkworm cocoon-mimicking structure via a bottom-up fabrication technique. CellMatrix not only provided optimal engineered biomimetic niche to facilitate cell growth but exhibited good photothermal conversion to dynamically regulate cell fates. Importantly, cell-CellMatrix construct could be directly implanted into defected tissues and improved tissue remodeling. Meanwhile, CellMatrix displayed good ice resistance and thermal conductivity, which maximally maintained cell viability and proliferation after the freeze-thawing process, allowing for storing precious cells and cell-CellMatrix construct. Thus, CellMatrix represents an all-in-one biomimetic platform for the culture-production-storage of therapeutically qualified cells.

Extracellular vesicles derived from mesenchymal stem/stromal cells: The regenerative impact in liver diseases

Liver dysfunctions are classified into acute and chronic diseases, which comprise a heterogeneous group of pathological features and a high mortality rate. Liver transplantation remains the gold-standard therapy for most liver diseases, with concomitant limitations related to donor organ shortage and lifelong immunosuppressive therapy. A concept in liver therapy intends to overcome these limitations based on the secreted extracellular vesicles (EVs; microvesicles and exosomes) by mesenchymal stem/stromal cells (MSCs). A significant number of studies have shown that factors released by MSCs could induce liver repair and ameliorate systemic inflammation through paracrine effects. It is well known that this paracrine action is based not only on the secretion of cytokines and growth factors but also on EVs, which regulate pathways associated with inflammation, hepatic fibrosis, integrin-linked protein kinase signaling, and apoptosis. Herein, we extensively discuss the differential effects of MSC-EVs on different liver diseases and on cellular and animal models and address the complex molecular mechanisms involved in the therapeutic potential of EVs. In addition, we cover the crucial information regarding the type of molecules contained in MSC-EVs that can be effective in the context of liver diseases. In conclusion, outcomes on MSC-EV-mediated therapy are expected to lead to an innovative, cell-free, noninvasive, less immunogenic, and nontoxic alternative strategy for liver treatment and to provide important mechanistic information on the reparative function of liver cells.

Injectable Self-Crosslinkable Thiolated Hyaluronic Acid for Stem Cell Therapy of Atopic Dermatitis

Stem cell therapies offer great promise in regenerative medicine to reinstate the normal function of diseased tissue, thereby avoiding the need for replacement. In stem cell therapies, damaged cells are replaced or restored by regulating inflammation and the immune system. However, the low survival rate and local retention of transplanted cells pose a significant challenge. In this study, injectable self-crosslinkable hydrogels using thiol-functionalized hyaluronic acid (HA-SH) were developed to improve the efficacy of mesenchymal stem cells (MSCs) for treating atopic dermatitis (AD)-related inflammatory lesions. The gelation kinetics and mechanical properties of HA-SH hydrogels were easily tuned by varying the concentration of the polymer in the precursor solution before injection. The MSC-laden HA-SH hydrogels exhibited high cell viability (>80%) for 1 week and good in vivo biocompatibility after implantation beneath the mouse skin. Moreover, the MSC-laden HA-SH hydrogel showed increased expression of anti-inflammatory cytokines, which can alleviate the immune response. In an AD animal model, a reduction in epidermal thickness and mast cell infiltration was achieved by applying a self-crosslinkable HA-SH solution including MSCs. This HA-based injectable hydrogel represents a potential carrier of stem cells, and its strong immunomodulation capabilities can be utilized for treating inflammation-related diseases.

Novel Therapies for the Treatment of Drug-Induced Liver Injury: A Systematic Review

Many drugs with different mechanisms of action and indications available on the market today are capable of inducing hepatotoxicity. Drug-induced liver injury (DILI) has been a treatment challenge nowadays as it was in the past. We searched Medline (via PubMed), CENTRAL, Science Citation Index Expanded, clinical trials registries and databases of DILI and hepatotoxicity up to 2021 for novel therapies for the management of adult patients with DILI based on the combination of three main search terms: 1) treatment, 2) novel, and 3) drug-induced liver injury. The mechanism of action of novel therapies, the potential of their benefit in clinical settings, and adverse drug reactions related to novel therapies were extracted. Cochrane Risk of bias tool and Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment approach was involved in the assessment of the certainty of the evidence for primary outcomes of included studies. One thousand three hundred seventy-two articles were identified. Twenty-eight articles were included in the final analysis. Eight randomized controlled trials (RCTs) were detected and for six the available data were sufficient for analysis. In abstract form only we found six studies which were also anaylzed. Investigated agents included: bicyclol, calmangafodipir, cytisin amidophospate, fomepizole, livina-polyherbal preparation, magnesium isoglycyrrhizinate (MgIG), picroliv, plasma exchange, radix Paeoniae Rubra, and S-adenosylmethionine. The primary outcomes of included trials mainly included laboratory markers improvement. Based on the moderate-certainty evidence, more patients treated with MgIG experienced alanine aminotransferase (ALT) normalization compared to placebo. Low-certainty evidence suggests that bicyclol treatment leads to a reduction of ALT levels compared to phosphatidylcholine. For the remaining eight interventions, the certainty of the evidence for primary outcomes was assessed as very low and we are very uncertain in any estimate of effect. More effort should be involved to investigate the novel treatment of DILI. Well-designed RCTs with appropriate sample sizes, comparable groups and precise, not only surrogate outcomes are urgently welcome.

Adipose-Derived Mesenchymal Stromal/Stem Cell Line Prevents Hepatic Ischemia/Reperfusion Injury in Rats by Inhibiting Inflammasome Activation

Mesenchymal stromal/stem cells (MSCs) have shown potential in the treatment of degenerative diseases, including ischemia/reperfusion injury (IRI), which occurs during organ transplantation and represents the main cause of post-transplant graft dysfunction. However, MSCs have heterogeneous characteristics, and studies of MSCs therapy have shown a variety of outcomes. To establish a new effective MSCs therapy, we developed an adipose-derived mesenchymal stromal/stem cell line (ASCL) and compared its therapeutic effects on primary adipose-derived MSCs (ASCs) using a hepatocyte co-culture model of hypoxia/reoxygenation in vitro and a rat model of hepatic IRI in vivo. The results showed that both ASCL and ASCs protect against hypoxia by improving hepatocyte viability, inhibiting reactive oxygen species release, and upregulating transforming growth factor-β in vitro. In vivo, ASCL or ASCs were infused into the spleen 24 h before the induction of rat hepatic IRI. The results showed that ASCL significantly improved the survival outcomes compared with the control (normal saline infusion) with the significantly decreased serum levels of liver enzymes and less damage to liver tissues compared with ASCs. Both ASCL and ASCs suppressed NOD-like receptor family pyrin domain-containing 3 inflammasome activation and subsequently reduced the release of activated IL-1β and IL-18, which is considered an important mechanism underlying ASCL and ASCs infusion in hepatic IRI. In addition, ASCL can promote the release of interleukin-1 receptor antagonist, which was previously reported as a key factor in hampering the inflammatory cascade during hepatic IRI. Our results suggest ASCL as a new candidate for hepatic IRI treatment due to its relatively homogeneous characteristics.

Magnetic Fe3 O4 @graphene oxide improves the therapeutic effects of embryonic stem cells on acute liver damage

OBJECTIVE

Acute liver failure is usually associated with inflammation and oxidation of hepatocytes and has high mortality and resource costs. Mesenchymal stem cell (MSCs) has occasionally been reported to have no beneficial effect due to poor transplantation and the survival of implanted cells. Recent studies showed that embryonic stem cell (ESC)-derived MSCs are an alternative for regenerative medicine. On the other hand, graphene-based nanostructures have proven useful in biomedicine. In this study, we investigated whether magnetic graphene oxide (MGO) improved the effects of ESC-MSC conditioned medium (CM) on protecting hepatocytes and stimulating the regeneration of damaged liver cells.

MATERIALS AND METHODS

To provide a rat model of acute liver failure, male rats were injected intraperitoneally with carbon tetrachloride (CCl4 ). The rats were randomly divided into six groups, namely control, sham, CCl4 , ESC-MSC-CM, MGO and ESC-MSC-CM + MGO. In the experimental groups, the rats received, depending on the group, 2 ml/kg body weight CCl4 and either ESC-MSC-CM with 5 × 106 MSCs or 300 μg/kg body weight MGO or both. Symptoms of acute liver failure appeared 4 days after the injection. All groups were compared and analysed both histologically and biochemically 4 days after the injection. Finally, the results of ESC-MSC-CM and MSC-CM were compared.

RESULTS

The results indicated that the use of MGO enhanced the effect of ESC-MSC-CM on reducing necrosis, inflammation, aspartate transaminase, alanine aminotransferase and alkaline phosphatase in the CCl4 -induced liver failure of the rat model. Also, the expression of vascular endothelial growth factor and matrix metalloproteinase-9 (MMP-9) was significantly upregulated after treatment with MGO. Also, the results showed that the ESC-MSC-CM has more efficient effective compared to MSC-CM.

CONCLUSION

Magnetic graphene oxide improved the hepatoprotective effects of ESC-MSC-CM on acute liver damage, probably by suppressing necrosis, apoptosis and inflammation of hepatocytes.

Application of some graphene derivatives to increase the efficiency of stem cell therapy

Graphene and its derivatives have application potential in many areas such as environmental technology, catalysis, biomedicine, and in particular, stem cell-based differentiation and regenerative therapies. Mesenchymal stem cell transplantation has emerged as a potential therapy for some diseases, such as acute kidney damage, liver failure and myocardial infarction. However, the poor survival of transplanted stem cells in such applications has significantly limited their therapeutic effectiveness. Graphene-based materials can improve the therapeutic efficacy of stem cells as they prevent the death of implanted cells by attaching them prior to implantation and increasing their paracrine secretion. In this review, we will highlight a number of recent studies that have investigated the potential use of graphene or its derivatives in stem cell applications and the prevention of transplanted stem cells from cell death, thereby improving their therapeutic efficacy.

The concurrent therapeutic potential of adipose-derived mesenchymal stem cells on Gentamycin-induced hepatorenal toxicity in rats

BACKGROUND

Adipose mesenchymal stem cells (AMSCs) are a type of stem cell employed to repair damaged organs. This study aimed to see how effective AMSCs are at treating gentamycin-induced hepatorenal damage in rats.

METHODS

18 male Wister rats were assigned into three groups; control, Gentamycin (GM), and GM+AMSCs. GM induced hepatorenal toxicity through daily injection (100 mg/kg, i.p.) for eight days. On day 9, AMSC (106 cells/ml/rat) was injected intravenously.

RESULTS

Creatinine, urea, uric acid, AST, ALP, ALT, TNF-, and MDA levels decreased, whereas IL-10, GSH, and CAT levels increased, indicating the therapeutic potency of intravenous injection AMSCs.

CONCLUSION

The current study demonstrated the simultaneous therapeutic efficacy of adipose mesenchymal stem cells on the liver and kidney in the treatment of Gentamycin-induced hepatotoxicity. These data show that AMSCs could be a feasible therapy option for liver and kidney disease.

Functional Mechanism of Bone Marrow-Derived Mesenchymal Stem Cells in the Treatment of Animal Models with Alzheimer's Disease: Inhibition of Neuroinflammation

The transplantation of bone marrow-derived mesenchymal stem cells (BMMSCs) alleviates neuropathology and improves cognitive deficits in animal models with Alzheimer’s disease. However, the underlying mechanisms remain to be determined. Available data demonstrate transplanted BMMSCs can inhibit neuroinflammation, which may be related to microglial M1/M2 polarization and is regulated by the secretion of autocrine and paracrine cytokines. BMMSCs also mitigate Aβ plaques and Tau tangles in the brain, which may be associated with the recruitment of peripheral blood monocytes and the subsequent comprehensive effects. The therapeutic effects of stem cells involve potential mechanisms such as immunomodulation, apoptosis, and proliferation. BMMSC-mediated functional reconstruction through dynamic remodeling develops a novel balance. Herein, present review recapitulates the molecular basis of BMMSC-assisted biological processes and summarizes the possible mechanisms related to the interaction between BMMSCs and microglia. The transplanted BMMSCs can suppress neuroinflammation that plays a key role in the pathogenesis of Alzheimer’s disease.

Menstrual blood-derived mesenchymal stem cells attenuate inflammation and improve the mortality of acute liver failure combining with A2AR agonist in mice

BACKGROUND AND AIM

Acute liver failure (ALF) poses a serious public health issue. The menstrual blood-derived mesenchymal stem cells (MenSCs) have been applied to cure various liver-related diseases. However, the efficacy and mechanism are far from clear. This study aims to explore the efficacy and potential mechanism of MenSCs to cure ALF.

METHODS

We investigate the potential mechanism of MenSCs on the ALF in vitro and in vivo. A2A adenosine receptor (A2AR) activation was investigated as the potential reinforcer for MenSCs treatment. Lipid polysaccharide/d-galactosamine (d-GalN) was employed to induce ALF. Diverse techniques were used to measure the inflammatory cytokines and key signaling molecules. Hematoxylin-eosin stain and aminotransaminases were applied to evaluate the liver injury. Flow cytometry was employed to assess the T cells.

RESULTS

The MenSCs can decrease the lipid polysaccharide-induced inflammatory cytokine elevation and related signaling molecules in ALF, including TLR4, phosphorylated-NF-kBp65 (p-NF-kBp65), PI3K, and p-AKT, p-mTOR and p-IKK in vitro. Moreover, MenSCs also can significantly reverse the liver injury, inflammatory cytokines elevation and related signaling molecules increase, and Treg/Th17 ratio decrease in vivo. In addition, MenSCs plus A2AR agonist can enhance the above changes.

CONCLUSIONS

The MenSCs can attenuate the ALF-induced liver injury via inhibition of TLR4-mediated PI3K/Akt/mTOR/IKK signaling. Then, this inhibits the p-NF-κBp65 translocate into nuclear, which causes a decrease of inflammatory cytokines release. Moreover, A2AR agonist can play a synergic role with MenSCs and enhance the above-mentioned effects.

Silica Magnetic Graphene Oxide Improves the Effects of Stem Cell-Conditioned Medium on Acute Liver Failure

OBJECTIVE

Acute liver failure (ALF) is usually associated with inflammation and oxidation of hepatocytes and has high mortality and resource costs. Although mesenchymal stem cell-conditioned medium (MSC-CM) has therapeutic effects similar to MSC transplant in treating liver failure, it may not increase survival. On the other hand, graphene-based nanostructures have been proven useful in biomedicine. In this study, we investigated whether silica magnetic graphene oxide (SMGO) improved the effects of MSC-CM in protecting hepatocytes and stimulating the regeneration of damaged liver cells.

MATERIALS AND METHODS

To provide a rat model of ALF, male rats were injected intraperitoneally with carbon tetrachloride (CCl₄). The rats were randomly divided into six groups, namely control, sham, CCl₄, MSC-CM, SMGO, and MSC-CM + SMGO. In the experimental groups, the rats received, depending on the group, 2 mL/kg body weight CCl₄ and either MSC-CM with 5 × 10⁶ MSCs or 300 μg/kg body weight SMGO or both. Symptoms of ALF appeared 4 days after the injection. All groups were compared and analyzed both histologically and biochemically 4 days after the injection.

RESULTS

The results indicated that the use of SMGO enhanced the effect of MSC-CM in reducing necrosis, inflammation, aspartate transaminase, alanine aminotransferase, and alkaline phosphatase in the CCl₄-induced liver failure of the rat model. Also, the expression of vascular endothelial growth factor and matrix metalloproteinase-9 (MMP-9) was significantly upregulated after treatment with SMGO.

CONCLUSION

SMGO improved the hepatoprotective effects of MSC-CM on acute liver damage, probably by suppressing necrosis, apoptosis, and inflammation of hepatocytes.

The Role of MSC in Wound Healing, Scarring and Regeneration

Tissue repair and regeneration after damage is not completely understood, and current therapies to support this process are limited. The wound healing process is associated with cell migration and proliferation, extracellular matrix remodeling, angiogenesis and re-epithelialization. In normal conditions, a wound will lead to healing, resulting in reparation of the tissue. Several risk factors, chronic inflammation, and some diseases lead to a deficient wound closure, producing a scar that can finish with a pathological fibrosis. Mesenchymal stem/stromal cells (MSCs) are widely used for their regenerative capacity and their possible therapeutically potential. Derived products of MSCs, such as exosomes or extravesicles, have shown a therapeutic potential similar to MSCs, and these cell-free products may be interesting in clinics. MSCs or their derivative products have shown paracrine beneficial effects, regulating inflammation, modifying the fibroblast activation and production of collagen and promoting neovascularization and re-epithelialization. This review describes the effects of MSCs and their derived products in each step of the wound repair process. As well, it reviews the pre-clinical and clinical use of MSCs to benefit in skin wound healing in diabetic associated wounds and in pathophysiological fibrosis.

Application of mesenchymal stem cell sheet to treatment of ischemic heart disease

In recent years, mesenchymal stem cells (MSCs) have been used to improve cardiac function and attenuate adverse ventricular remodeling of the ischemic myocardium through paracrine effects and immunoregulation functions. In combination with cell sheet technology, MSCs could be more easily transplanted to the ischemic area. The long-term retention of MSCs in the affected area was realized and significantly improved the curative effect. In this review, we summarized the research and the applications of MSC sheets to the treatment of ischemic heart tissue. At present, many types of MSCs have been considered as multipotent cells in the treatment of heart failure, such as bone marrow-derived mesenchymal stem cells (BM-MSCs), adipose-derived mesenchymal stem cells (AD-MSCs), umbilical cord-derived mesenchymal stem cells (UC-MSCs), and skeletal myoblasts (SMs). Since UC-MSCs have few human leukocyte antigen-II and major histocompatibility complex class I molecules, and are easy to isolate and culture, UC-MSC sheets have been proposed as a candidate for clinical applications to ischemic heart disease.

Macro-encapsulation of mesenchymal stem cells in acute and chronic liver injury animal models

BACKGROUND AND AIM

Stem cell treatments using scaffolds for liver disease have been well studied. However, macro-encapsulation of mesenchymal stem cells (MSCs) to minimize or inhibit stem cell homing has not been evaluated. Here, we conducted a proof-of-concept study using MSCs macro-encapsulated in poly lactic-co-glycolic acid in liver disease models.

METHODS

Poly lactic-co-glycolic acid semipermeable membranes (surface pore size up to 40 μm) were used as the macro-encapsulation system. Macro-encapsulated pouches were loaded with MSCs and sealed. Each pouch was implanted in the subcutaneous region of the dorsum or interlobular space of the liver. Acute liver injury was induced using thioacetamide intraperitoneal injection thrice a week. For the chronic liver fibrosis model, thioacetamide dose was gradually increased, starting from 100 to 400 mg/kg over 16 weeks (thrice a week).

RESULTS

In the acute liver injury model, the treated groups showed decreased liver inflammation and necrosis compared with the control. Hepatic fibrosis decreased in the treated group in the chronic liver fibrosis model compared with that in the control group. Encapsulated MSCs exhibited changed cell morphology and characteristics after implantation, showing increased periodic acid-Schiff staining and CYP2E1 expression. Migration and homing of MSCs into the liver was not observed. Under hypoxic conditions, macro-encapsulated MSCs secreted more growth hormones, including vascular endothelial growth factor, platelet-derived growth factor, angiopoietin-2, and placental growth factor, than monolayered MSCs in vitro.

CONCLUSIONS

Macro-encapsulated MSCs attenuate hepatic inflammation and fibrosis by upregulating hypoxia-induced growth hormone secretion in liver disease models.

Liver transplantation in acute liver failure: Dilemmas and challenges

Acute liver failure (ALF) refers to a state of severe hepatic injury that leads to altered coagulation and sensorium in the absence of pre-existing liver disease. ALF has different causes, but the clinical characteristics are strikingly similar. In clinical practice, however, inconsistency in the definition of ALF worldwide and confusion regarding the existence of pre-existing liver disease raise diagnostic dilemmas. ALF mortality rates used to be over 80% in the past; however, survival rates on medical treatment have significantly improved in recent years due to a greater understanding of pathophysiology and advances in critical care management. The survival rates in acetaminophen-associated ALF have become close to the post-transplant survival rates. Given that liver transplantation (LT) is an expensive treatment that involves a major surgical operation in critically ill patients and lifelong immunosuppression, it is very important to select accurate patients who may benefit from it. Still, emergency LT remains a lifesaving procedure for many ALF patients. However, there is a lack of consistency in current prognostic models that hampers the selection of transplant candidates in a timely and precise manner. The other problems associated with LT in ALF are the shortage of graft, development of contraindications on the waiting list, vaguely defined delisting criteria, time constraints for pre-transplant evaluation, ethical concerns, and comparatively poor post-transplant outcomes in ALF. Therefore, there is a desperate need to establish accurate prognostic models and explore the roles of evolving adjunctive and alternative therapies, such as liver support systems, plasma exchange, stem cells, auxiliary LT, and so on, to enhance transplant-free survival and to fill the void created by the graft shortage

Identification of a potent ionizable lipid for efficient macrophage transfection and systemic anti-interleukin-1β siRNA delivery against acute liver failure

RNA interference (RNAi) therapy has great potential for treating inflammatory diseases. However, the development of potent carrier materials for delivering siRNA to macrophages is challenging. Herein, we design a set of ionizable lipid nanoparticles (LNPs) to screen and identify a potent carrier of siRNA for silencing an essential pro-inflammatory cytokine, interleukin-1β (IL-1β) in macrophages. The top performance LNP (114-LNP), containing ionizable lipid with spermine as an amine-head group, facilitated efficient siRNA internalization via multiple endocytosis pathways and achieved effective endosome escape in macrophages. The optimized LNP/siIL-1β achieved strong silencing of IL-1β in both activated Raw 264.7 cells and primary macrophages. Furthermore, systematic administration of 114-LNP/siIL-1β complexes could effectively inhibit IL-1β expression in an acute liver failure model and significantly attenuated hepatic inflammation and liver damage. These results suggest that the optimized ionizable lipid nanoparticle represents a promising platform for anti-inflammation therapies.

The Application of Mesenchymal Stem Cells in the Treatment of Liver Diseases: Mechanism, Efficacy, and Safety Issues

Mesenchymal stem cell (MSC) transplantation is a novel treatment for liver diseases due to the roles of MSCs in regeneration, fibrosis inhibition and immune regulation. However, the mechanisms are still not completely understood. Despite the significant efficacy of MSC therapy in animal models and preliminary clinical trials, issues remain. The efficacy and safety of MSC-based therapy in the treatment of liver diseases remains a challenging issue that requires more investigation. This article reviews recent studies on the mechanisms of MSCs in liver diseases and the associated challenges and suggests potential future applications.

VEGF165 gene-modified human umbilical cord blood mesenchymal stem cells protect against acute liver failure in rats

BACKGROUND

Human umbilical cord blood mesenchymal stem cells (HUCB-MSCs) can exert a protective effect in rat models of acute liver failure (ALF). Vascular endothelial growth factor 165 (VEGF₁₆₅ ) is the predominant VEGF isoform and possesses a strong pro-angiogenic function. In the present study, HUCB-MSC served as the gene delivery vehicle for the VEGF₁₆₅ gene, and we explored the therapeutic effects of this system on ALF.

METHODS

HUCB-MSCs were infected with an adenovirus expressing green fluorescent protein (GFP)-VEFG fusion protein (Ad-VEGF₁₆₅ ) to overexpress VEGF₁₆₅ or an adenovirus expressing GFP (Ad-GFP) as control. The control and modified HUCB-MSCs were then transplanted into ALF model rats. Liver function and liver pathological changes were assessed by biochemical tests and liver histology. Immunohistochemistry was carried out to determine the expression of, CD34, Ki67 and VEGF.

RESULTS

VEGF₁₆₅ overexpression enhanced the multipotency of HUCB-MSCs and promoted the homing and colonization of HUCB-MSC in the liver tissues of ALF rats. Furthermore, although HUCB-MSC transplantation ameliorated liver damage and promoted liver regeneration to some extent in ALF rats, Ad-VEGF₁₆₅ -HUCB-MSC transplantation showed stronger therapeutic effects on ALF.

CONCLUSIONS

In summary, transplantation of VEGF₁₆₅ -modified HUCB-MSCs exert stronger therapeutic effects on ALF than HUCB-MSCs. The present study provides a novel therapeutic approach for ALF.

Bio-mimicking Shear Stress Environments for Enhancing Mesenchymal Stem Cell Differentiation

Mesenchymal stem cells (MSCs) are multipotent stromal cells, with the ability to differentiate into mesodermal (e.g., adipocyte, chondrocyte, hematopoietic, myocyte, osteoblast), ectodermal (e.g., epithelial, neural) and endodermal (e.g., hepatocyte, islet cell) lineages based on the type of induction cues provided. As compared to embryonic stem cells, MSCs hold a multitude of advantages from a clinical translation perspective, including ease of isolation, low immunogenicity and limited ethical concerns. Therefore, MSCs are a promising stem cell source for different regenerative medicine applications. The in vitro differentiation of MSCs into different lineages relies on effective mimicking of the in vivo milieu, including both biochemical and mechanical stimuli. As compared to other biophysical cues, such as substrate stiffness and topography, the role of fluid shear stress (SS) in regulating MSC differentiation has been investigated to a lesser extent although the role of interstitial fluid and vascular flow in regulating the normal physiology of bone, muscle and cardiovascular tissues is well-known. This review aims to summarise the current state-of-the-art regarding the role of SS in the differentiation of MSCs into osteogenic, cardiovascular, chondrogenic, adipogenic and neurogenic lineages. We will also highlight and discuss the potential of employing SS to augment the differentiation of MSCs to other lineages, where SS is known to play a role physiologically but has not yet been successfully harnessed for in vitro differentiation, including liver, kidney and corneal tissue lineage cells. The incorporation of SS, in combination with biochemical and biophysical cues during MSC differentiation, may provide a promising avenue to improve the functionality of the differentiated cells by more closely mimicking the in vivo milieu.

Stem cell transplantation for treating liver diseases: progress and remaining challenges

With the development of regenerative medicine, various stem cells are increasingly considered for treating liver diseases. Various stem cells have been reported to play an essential role in liver recovery, and studies have verified the preliminary effectiveness and safety of these therapies. Stem cell-based therapies will emerge as an effective treatment strategy for liver diseases. Thus, the research progress and challenges to the related stem cells were reviewed, namely the classification of stem cells, cell culture, transplantation, cell tracing in the body, therapies for various liver diseases.

Mesenchymal stromal cell secretome in liver failure: Perspectives on COVID-19 infection treatment

Due to their immunomodulatory potential and release of trophic factors that promote healing, mesenchymal stromal cells (MSCs) are considered important players in tissue homeostasis and regeneration. MSCs have been widely used in clinical trials to treat multiple conditions associated with inflammation and tissue damage. Recent evidence suggests that most of the MSC therapeutic effects are derived from their secretome, including the extracellular vesicles, representing a promising approach in regenerative medicine application to treat organ failure as a result of inflammation/fibrosis. The recent outbreak of respiratory syndrome coronavirus, caused by the newly identified agent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has forced scientists worldwide to use all available instruments to fight the infection, including the inflammatory cascade caused by this pandemic disease. The use of MSCs is a valid approach to combat organ inflammation in different compartments. In addition to the lungs, which are considered the main inflammatory target for this virus, other organs are compromised by the infection. In particular, the liver is involved in the inflammatory response to SARS-CoV-2 infection, which causes organ failure, leading to death in coronavirus disease 2019 (COVID-19) patients. We herein summarize the current implications derived from the use of MSCs and their soluble derivatives in COVID-19 treatment, and emphasize the potential of MSC-based therapy in this clinical setting.

An update on the pharmacological management of autoimmune hepatitis

Introduction: Autoimmune hepatitis (AIH) is an immune mediated, inflammatory disease affecting the liver as a result of environmental triggers in susceptible individuals leading to loss of self-tolerance. The immunopathogenesis of AIH is not fully understood, which limits targeted therapeutic options.Areas covered: In this review, the authors provide an overview of current practice in the management of AIH, which include induction therapy with corticosteroids (± thiopurines), followed by maintenance therapy. Lack of early response to treatment may serve as a predictor of those at risk of requiring treatment escalation to second- and third-line agents such as mycophenolate mofetil (MMF), calcineurin inhibitors or biologics. Evidence for third-line agents from small retrospective studies or individual centers are reviewed. The nuances of AIH treatment in pregnancy, overlap syndromes, and drug induced liver injury (DILI) warrant further consideration.Expert opinion: Augmenting the balance of regulatory T cells (Treg) and effector T cells is an appealing therapeutic target with a multitude of agents in development. Many of the challenges in AIH research are due to its rarity and lack of randomized data. Management of AIH should strive towards individualized care through risk stratification and use of the best therapeutic modality for each patient.

Mesenchymal Stem Cells Transplantation in Intracerebral Hemorrhage: Application and Challenges

Intracerebral hemorrhage (ICH) is one of the leading causes of death and long-term disability worldwide. Mesenchymal stem cell (MSC) therapies have demonstrated improved outcomes for treating ICH-induced neuronal defects, and the neural network reconstruction and neurological function recovery were enhanced in rodent ICH models through the mechanisms of neurogenesis, angiogenesis, anti-inflammation, and anti-apoptosis. However, many key issues associated with the survival, differentiation, and safety of grafted MSCs after ICH remain to be resolved, which hinder the clinical translation of MSC therapy. Herein, we reviewed an overview of the research status of MSC transplantation after ICH in different species including rodents, swine, monkey, and human, and the challenges for MSC-mediated ICH recovery from pathological microenvironment have been summarized. Furthermore, some efficient strategies for the outcome improvement of MSC transplantation were proposed.

Co-Culture of Human Mesenchymal Stromal Cells and Primary Mouse Hepatocytes

Human mesenchymal stromal cells (MSC) are adult stem cells, which feature hepatotropism by supporting liver regeneration through amelioration of hepatic inflammation and lipid accumulation in a mouse model of non-alcoholic steatohepatitis (NASH), a more advanced stage of fatty liver. It remains open, how MSC impact on hepatocytic lipid metabolism. To study MSC actions on fatty liver mechanistically, we established an in vitro model of co-culture comprising MSC and isolated mouse hepatocytes at a ratio of 1:1. Lipid storage in hepatocytes was induced by the treatment with medium deficiency of methionine and choline (MCD). The protocol can be adapted for the use of other lipid storage-inducing agents such as palmitic acid and linoleic acid. This co-culture model allows to study, e.g., whether MSC act indirectly via MSC-born paracrine mechanisms or through direct physical interactions between cells beside others. The protocol allows us to detect the formation of extensions (filopodia) from MSC to contact the fatty hepatocytes or other MSC within 24 h of co-culture. These structures may represent tunneling nanotubes (TNT), allowing for long-range intercellular communication.

Applications of Nanobiomaterials in the Therapy and Imaging of Acute Liver Failure

This review focuses on the therapeutic mechanisms, targeting strategies of various nanomaterials in acute liver failure, and recent advances of diverse nanomaterials for acute liver failure therapy, diagnosis, and imaging. This review provides an outlook on the applications of nanomaterials, especially on the new horizons in acute liver failure therapy, and inspires broader interests across various disciplines. Acute liver failure (ALF), a fatal clinical disease featured with overwhelming hepatocyte necrosis, is a grand challenge in global health. However, a satisfactory therapeutic option for curing ALF is still absent, other than liver transplantation. Nanobiomaterials are currently being developed for the diagnosis and treatment of ALF. The liver can sequester most of nanoparticles from blood circulation, which becomes an intrinsic superiority for nanobiomaterials targeting hepatic diseases. Nanobiomaterials can enhance the bioavailability of free drugs, thereby significantly improving the therapeutic effects in ALF. Nanobiomaterials can also increase the liver accumulation of therapeutic agents and enable more effective targeting of the liver or specific liver cells. In addition, stimuli-responsive, optical, or magnetic nanomaterials exhibit great potential in the therapeutical, diagnostic, and imaging applications in ALF. Therefore, therapeutic agents in combination with nanobiomaterials increase the specificity of ALF therapy, diminish adverse systemic effects, and offer a multifunctional theranostic platform. Nanobiomaterial holds excellent significance and prospects in ALF theranostics. In this review, we summarize the therapeutic mechanisms and targeting strategies of various nanobiomaterials in ALF. We highlight recent developments of diverse nanomedicines for ALF therapy, diagnosis, and imaging. Furthermore, the challenges and future perspectives in the theranostics of ALF are also discussed.

Cell Therapy for Liver Disease: From Promise to Reality

Over the last decade, there has been a considerable progress in the development of cell therapy products for the treatment of liver diseases. The quest to generate well-defined homogenous cell populations with defined mechanism(s) of action has enabled the progression from use of autologous bone marrow stem cells comprising of heterogeneous cell populations to allogeneic cell types such as monocyte-derived macrophages, regulatory T cells, mesenchymal stromal cells, macrophages, etc. There is growing evidence regarding the multiple molecular mechanisms pivotal to various therapeutic effects and hence, careful selection of cell therapy product for the desired putative effects is crucial. In this review, we have presented an overview of the cell therapies that have been developed thus far, with preclinical and clinical evidence for their use in liver disease. Limitations associated with these therapies have also been discussed. Despite the advances made, there remain multiple challenges to overcome before cell therapies can be considered as viable treatment options, and these include larger scale clinical trials, scalable production of cells according to good manufacturing practice standards, pathways for delivery of cell therapy within hospital environments, and costs associated with the production.

Three Cases of Alcohol-Induced Acute-On-Chronic Liver Failure With Successful Support by Adipose-Derived Stem Cells

OBJECTIVES:

Acute liver failure (ALF) and acute-on-chronic liver failure (AOCLF) are critical medical conditions with urgent therapy requirements. When ALF or AOCLF are due to alcohol intoxication or based on chronic alcohol abuse, virtually, no therapeutic options are available as liver transplantation is prohibited. In this case series, treatment of alcohol-induced ALF/AOCLF with adipose--derived stem cells (ASC) was tested under compassionate use.

METHODS:

ASC from 2 donors were isolated, cultured, and expanded by established protocols. ASC were administered to 3 individuals with either ALF or AOCLF due to alcohol abuse under compassionate use. Clinical presentation, serum measurements, and other diagnostic methods were compiled before ASC treatment and during the disease course after ASC administration.

RESULTS:

Three patients were admitted to the Department of Gastroenterology, Hepatology, and Infectious Diseases (University Hospital Magdeburg) with acute or AOCLF due to alcohol abuse. All 3 patients presented in impaired general condition and with elevated, in 1 case drastically elevated, serum liver enzyme concentrations. Treatment with ASC led to improvements in general condition and reduction of serum transaminases. In 2 cases, reduction of liver stiffness and increase of liver function by the C¹³ methacetin breath test were observed after ASC treatment. Recovery to a normal condition was achieved between 1 and 2 months after ASC treatment. No adverse effects associated to ASC treatment were observed.

DISCUSSION:

ASC treatment may be a feasible option to enhance recovery from alcohol-induced ALF or AOCLF. ASC treatment seems safe in the presented cases.

Cargo-laden erythrocyte ghosts target liver mediated by macrophages

Liver-targeted cargo delivery possesses great potential for the treatment of liver disease. It is urgent to find an efficient and biocompatible liver targeted delivery system. This study focused on the liver targeting properties of erythrocyte ghosts and its possible mechanism. Herein, we optimized conditions to fabricate human and mouse erythrocyte ghosts with sufficient room capable of incorporating various model substances. Erythrocyte ghosts are biocompatible cargo carriers because it is derived from autologous red blood cells (RBCs), and the cell size, zeta potential, and biconcave-disk shape of the ghosts were consistent with those of RBCs. An in vivo imaging system and positron emission tomography/computed tomography imaging showed that the ghosts were captured mainly in the liver by intravenous injection of fluorescence or ¹⁸F-fluorodeoxyglucose (FDG)-labelled ghosts into mice. In contrast, the main concentration of naked octreotide was trapped in the lungs while naked ¹⁸F-FDG was trapped in the heart. However, the concentration of cargo-loaded ghosts decreased significantly in the liver in macrophage-depleted mice. Accordingly, in vitro experiments showed that higher phosphatidylserine exposure was observed in the ghosts (38.9 %) compared to normal erythrocytes (0.69 %), and the phagocytic activity of the macrophage RAW 264.7. on the ghosts was significantly higher than that of normal erythrocytes (p < 0.001). Together they indicate that erythrocyte ghosts show liver targeting properties, and possibly owing to macrophage phagocytosis. This promising and effective therapeutic delivery system may provide therapeutic benefits for liver disease.

Current concepts in acute liver failure

Acute liver failure (ALF) is a severe condition secondary to a myriad of causes associated with poor outcomes. The prompt diagnosis and identification of the aetiology allow the administration of specific treatments plus supportive strategies and to define the overall prognosis, the probability of developing complications and the need for liver transplantation. Pivotal issues are adequate monitoring and the institution of prophylactic strategies to reduce the risk of complications, such as progressive liver failure, cerebral oedema, renal failure, coagulopathies or infections. In this article, we review the main aspects of ALF, including the definition, diagnosis and complications. Also, we describe the standard-of-care strategies and recent advances in the treatment of ALF. Finally, we include our experience of care patients with ALF.

IL-1β Pretreatment Improves the Efficacy of Mesenchymal Stem Cells on Acute Liver Failure by Enhancing CXCR4 Expression

BACKGROUND

Mesenchymal stem cells (MSCs), with the powerful metabolic and functional supporting abilities for inflammatory diseases, may be an effective therapeutic strategy for acute liver failure (ALF). However, the efficacy of MSCs can still be promoted if pretreatment is applied to enhance their poor migration towards the damaged liver. The purpose of this study is to determine the effect of IL-1β pretreatment on the efficacy and homing ability of MSCs in ALF.

METHODS

MSCs were isolated by the whole bone marrow adherence method and characterized. The efficacy and homing ability of IL-1β-pretreated MSCs (Pre-MSCs) were examined in a rat ALF model and compared with that of MSCs and normal saline. Then, Western blot was performed to detect the c-Met and CXCR4 expression of MSCs and Pre-MSCs and followed by flow cytometry to detect the meaningful indicators. Finally, the migration abilities of different cells and different conditions were tested by the Transwell migration assay.

RESULTS

MSCs of ideal purity were successfully isolated and cultured. Comparing with MSCs, Pre-MSCs had significantly better efficacy on improving the survival rate and liver function of ALF rats. Further analyses of damaged liver tissues showed that IL-1β pretreatment significantly enhanced the efficacy of MSCs on suppressing liver necrosis. Besides, Pre-MSCs exhibited better effects in inhibiting apoptosis and activating proliferation. The results of tracing experiments with CM-Dil-labeled cells confirmed that more cells migrated to the damaged liver in the Pre-MSC group. In terms of mechanism, the CXCR4 expression was significantly enhanced by IL-1β pretreatment, and an increased migration ability towards SDF-1 that could be reversed by AMD3100 was found in Pre-MSCs.

CONCLUSION

IL-1β pretreatment could enhance the homing ability of MSCs at least partially by increasing the expression of CXCR4 and further improve the efficacy of MSCs on ALF.