Mesenchymal Stem Cell Therapy in Acute Liver Failure

Small Extracellular Vesicles Engineered Using Click Chemistry to Express Chimeric Antigen Receptors Show Enhanced Efficacy in Acute Liver Failure

Acetaminophen (APAP) overdose can cause severe liver injury and life-threatening conditions that may lead to multiple organ failure without proper treatment. N-acetylcysteine (NAC) is the accepted and prescribed treatment for detoxification in cases of APAP overdose. Nonetheless, in acute liver failure (ALF), particularly when the ingestion is substantial, NAC may not fully restore liver function. NAC administration in ALF has limitations and potential adverse effects, including nausea, vomiting, diarrhoea, flatus, gastroesophageal reflux, and anaphylactoid reactions. Mesenchymal stromal cell (MSC)-based therapies using paracrine activity show promise for treating ALF, with preclinical studies demonstrating improvement. Recently, MSC-derived extracellular vesicles (EVs) have emerged as a new therapeutic option for liver injury. MSC-derived EVs can contain various therapeutic cargos depending on the cell of origin, participate in physiological processes, and respond to abnormalities. However, most therapeutic EVs lack a distinct orientation upon entering the body, resulting in a lack of targeting specificity. Therefore, enhancing the precision of natural EV delivery systems is urgently needed. Thus, we developed an advanced targeting technique to deliver modified EVs within the body. Our strategy aims to employ bioorthogonal click chemistry to attach a targeting molecule to the surface of small extracellular vesicles (sEVs), creating exogenous chimeric antigen receptor-modified sEVs (CAR-sEVs) for the treatment. First, we engineered azido-modified sEVs (N3-sEVs) through metabolic glycoengineering by treating MSCs with the azide-containing monosaccharide N-azidoacetyl-mannosamine (Ac4ManNAz). Next, we conjugated N3-sEVs with a dibenzocyclooctyne (DBCO)-tagged single-chain variable fragment (DBCO-scFv) that targets the asialoglycoprotein receptor (ASGR1), thus producing CAR-sEVs for precise liver targeting. The efficacy of CAR-sEV therapy in ALF models by targeting ASGR1 was validated. MSC-derived CAR-sEVs reduced serum liver enzymes, mitigated liver damage, and promoted hepatocyte proliferation in APAP-induced injury. Overall, CAR-sEVs exhibited enhanced hepatocyte specificity and efficacy in ameliorating liver injury, highlighting the significant advancements achievable with cell-free targeted therapy.

Ethical frontiers in liver transplantation

Liver transplantation represents a pivotal intervention in the management of end-stage liver disease, offering a lifeline to countless patients. Despite significant strides in surgical techniques and organ procurement, ethical dilemmas and debates continue to underscore this life-saving procedure. Navigating the ethical terrain surrounding this complex procedure is hence paramount. Dissecting the nuances of ethical principles of justice, autonomy and beneficence that underpin transplant protocols worldwide, we explore the modern challenges that plaques the world of liver transplantation. We investigate the ethical dimensions of organ transplantation, focusing on allocation, emerging technologies, and decision-making processes. PubMed, Scopus, Web of Science, Embase and Central were searched from database inception to February 29, 2024 using the following keywords: "liver transplant", "transplantation", "liver donation", "liver recipient", "organ donation" and "ethics". Information from relevant articles surrounding ethical discussions in the realm of liver transplantation, especially with regards to organ recipients and allocation, organ donation, transplant tourism, new age technologies and developments, were extracted. From the definition of death to the long term follow up of organ recipients, liver transplantation has many ethical quandaries. With new transplant techniques, societal acceptance and perceptions also play a pivotal role. Cultural, religious and regional factors including but not limited to beliefs, wealth and accessibility are extremely influential in public attitudes towards donation, xenotransplantation, stem cell research, and adopting artificial intelligence. Understanding and addressing these perspectives whilst upholding bioethical principles is essential to ensure just distribution and fair allocation of resources. Robust regulatory oversight for ethical sourcing of organs, ensuring good patient selection and transplant techniques, and high-quality long-term surveillance to mitigate risks is essential. Efforts to promote equitable access to transplantation as well as prioritizing patients with true needs are essential to address disparities. In conclusion, liver transplantation is often the beacon of hope for individuals suffering from end-stage liver disease and improves quality of life. The ethics related to transplantation are complex and multifaceted, considering not just the donor and the recipient, but also the society as a whole.

Long-term expanded hepatic progenitor cells ameliorate D-GalN/LPS-induced acute liver failure through repolarizing M1 macrophage to M2-Like phenotype via activation of the IL-10/JAK2/STAT3 signaling pathway

Acute liver failure (ALF) is a devastating liver disease characterized by the rapid deterioration of hepatocytes, which causes a series of clinical complications, including hepatic dysfunction, coagulopathy, encephalopathy, and multiorgan failure. Cell-based therapy is a promising alternative as it can bridge patients until their livers regenerate, releasing immunomodulatory molecules to suppress inflammation. This study reports an iPSCs-derived long-term expanded hepatic progenitor cell (LTHepPCs), which can differentiate into hepatocyte-like cells (HLCs) in vivo. When introduced into drug-induced ALF models, LTHepPCs mitigate liver damage by modulating the local immune microenvironment. This is achieved by shifting macrophages/Kupffer cells towards an anti-inflammatory state, resulting in a decrease in the expression of inflammatory cytokines such as TNF-a, IL-1β, and IL-8, and an increase in the expression of anti-inflammatory cytokines such as IL-10 and ARG-1. In vitro co-culturing of THP-1 or mBMDMs with LTHepPCs suggested that LTHepPCs could activate the anti-inflammatory state of macrophages/Kupffer cells via the IL-10/JAK2/STAT3 signaling pathway. Therefore, LTHepPC transplantation is a promising therapy for ALF patients.

Application of mesenchymal stem cells in liver fibrosis and regeneration

Liver transplantation remains the most effective treatment for end-stage liver disease (ESLD), but it is fraught with challenges such as immunosuppression, high risk and cost, and donor shortage. In recent years, stem cell transplantation has emerged as a promising new strategy for ESLD treatment, with mesenchymal stem cells (MSCs) gaining significant attention because of their unique properties. MSCs can regulate signaling pathways, including hepatocyte growth factor/c-Met, Wnt/beta (β)-catenin, Notch, transforming growth factor-β1/Smad, interleukin-6/Janus kinase/signal transducer and activator of transcription 3, and phosphatidylinositol 3-kinase/PDK/Akt, thereby influencing the progression of liver fibrosis and regeneration. As a promising stem cell type, MSCs offer numerous advantages in liver disease treatment, including low immunogenicity; ease of acquisition; unlimited proliferative ability; pluripotent differentiation potential; immunomodulatory function; and anti-inflammatory, antifibrotic, and antiapoptotic biological characteristics. This review outlines the mechanisms by which MSCs reverse liver fibrosis and promote liver regeneration. MSCs are crucial in reversing liver fibrosis and repairing liver damage through the secretion of growth factors, regulation of signaling pathways, and modulation of immune responses. MSCs have shown good therapeutic effects in preclinical and clinical studies, providing new strategies for liver disease treatment. However, challenges still exist in the clinical application of MSCs, including low differentiation efficiency and limited sources. This review provides a reference for MSC application in liver disease treatment. With the continuous progress in MSC research, MSCs are expected to achieve breakthroughs in liver disease treatment, thereby improving patient treatment outcomes.

Cellular Plasticity in Gut and Liver Regeneration

The intestine and liver share a unique regenerative property that sets them apart from other mammalian visceral organs. The intestinal epithelium exhibits rapid renewal, making it one of the fastest renewing tissues in humans. Under physiological conditions, intestinal stem cells within each intestinal crypt continuously differentiate into the different types of intestinal epithelial cells to maintain intestinal homeostasis. However, when exposed to tissue damage or stressful conditions such as inflammation, intestinal epithelial cells in the gastrointestinal tract exhibit plasticity, allowing fully differentiated cells to regain their stem cell properties. Likewise, hepatic epithelial cells possess a remarkable regenerative capacity to restore lost liver mass through proliferation-mediated liver regeneration. When the proliferation-mediated regenerative capacity is impaired, hepatocytes and biliary epithelial cells (BECs) can undergo plasticity-mediated regeneration and replenish each other. The transition of mammalian liver progenitor cells to hepatocytes/BECs can be observed under tightly controlled experimental conditions such as severe hepatocyte injury accompanied by the loss of regenerative capacity. In this review, we will discuss the mechanism by which cellular plasticity contributes to the regeneration process and the potential therapeutic implications of understanding and harnessing cellular plasticity in the gut and liver.

Use of Mesenchymal Stem Cell Transplantation as a Treatment for Liver Cirrhosis in Animal Models

INTRODUCTION

Liver cirrhosis is one of the top 10 causes of death worldwide, and liver disease is in the top five in many developing countries. The treatment of liver cirrhosis at various stages necessitates the development of new organ transplantation techniques. One of these options is cell therapy, which has lately been used to treat a wide range of illnesses.

METHODS

The study used a rabbit model of liver cirrhosis to examine the efficiency of mesenchymal stem cell (MSC) transplantation. Subcutaneous injections of carbon tetrachloride (CCL4) were used to cause liver cirrhosis. When liver cirrhosis developed, autologous mesenchymal stem cells were infused into the portal vein.

RESULTS

The histological image of the cirrhotic liver improved one month after MSC transplantation.

CONCLUSION

This demonstrates that the intraportal delivery of autologous MSC to rabbits with experimental liver cirrhosis has good therapeutic outcomes.

Mesenchymal Stem Cells Alleviate Acute Liver Failure through Regulating Hepatocyte Apoptosis and Macrophage Polarization

Background and Aims

Acute liver failure (ALF) is a life-threatening clinical problem with limited treatment options. Administration of human umbilical cord mesenchymal stem cells (hUC-MSCs) may be a promising approach for ALF. This study aimed to explore the role of hUC-MSCs in the treatment of ALF and the underlying mechanisms.

Methods

A mouse model of ALF was induced by lipopolysaccharide and d-galactosamine administration. The therapeutic effects of hUC-MSCs were evaluated by assessing serum enzyme activity, histological appearance, and cell apoptosis in liver tissues. The apoptosis rate was analyzed in AML12 cells. The levels of inflammatory cytokines and the phenotype of RAW264.7 cells co-cultured with hUC-MSCs were detected. The C-Jun N-terminal kinase/nuclear factor-kappa B signaling pathway was studied.

Results

The hUC-MSCs treatment decreased the levels of serum alanine aminotransferase and aspartate aminotransferase, reduced pathological damage, alleviated hepatocyte apoptosis, and reduced mortality in vivo. The hUC-MSCs co-culture reduced the apoptosis rate of AML12 cells in vitro. Moreover, lipopolysaccharide-stimulated RAW264.7 cells had higher levels of tumor necrosis factor-α, interleukin-6, and interleukin-1β and showed more CD86-positive cells, whereas the hUC-MSCs co-culture reduced the levels of the three inflammatory cytokines and increased the ratio of CD206-positive cells. The hUC-MSCs treatment inhibited the activation of phosphorylated (p)-C-Jun N-terminal kinase and p-nuclear factor-kappa B not only in liver tissues but also in AML12 and RAW264.7 cells co-cultured with hUC-MSCs.

Conclusions

hUC-MSCs could alleviate ALF by regulating hepatocyte apoptosis and macrophage polarization, thus hUC-MSC-based cell therapy may be an alternative option for patients with ALF.

Pre-administration of human umbilical cord mesenchymal stem cells has better therapeutic efficacy in rats with D-galactosamine-induced acute liver failure

BACKGROUND

Acute liver failure (ALF) is characterized by an intense systemic inflammatory response, single or multiple organ system failure and high mortality. However, specific and effective treatments for ALF patients are still lacking. According to the current investigation, human umbilical cord mesenchymal stem cells (hUCMSCs) have shown remarkable potential to enhance the functional recovery of injured livers. We aimed to investigate the therapeutic effects of time-differentiated hUCMSCs administration regimens on ALF.

METHODS

The rat model of ALF was induced by D-galactosamine (D-gal), and hUCMSCs were administered via the tail vein 12 h before or 2 h after induction. The potential mechanisms of hUCMSCs in treatment of ALF, regulation cell subset and secretion of inflammatory factors, were verified by co-culturing with PBMCs in vitro. Liver function indicators were detected by an automatic biochemistry analyzer and inflammatory factors were obtained by ELISA detection. The distribution of hUCMSCs in rats after administration was followed by quantitative real-time fluorescence PCR.

RESULTS

The findings of the study discovered that administration of hUCMSCs 12 h prior to surgery could significantly improve the survival rate of rats, stabilize various liver function indicators in serum levels of ALT, AST, T-BIL, or ALB diminish inflammatory infiltration in liver tissue, and inhibit the secretion of inflammatory factors.

CONCLUSION

Our data showed that pre-transplantation of hUCMSCs had a better therapeutic effect on ALF rats, providing empirical evidence for preclinical studies. Thus, the timing of hUCMSCs transplantation is necessary for the optimal clinical treatment effect.

Human umbilical cord mesenchymal stem cells protect against ferroptosis in acute liver failure through the IGF1-hepcidin-FPN1 axis and inhibiting iron loading

Acute liver failure (ALF) is a significant global issue with elevated morbidity and mortality rates. There is an urgent and pressing need for secure and effective treatments. Ferroptosis, a novel iron-dependent regulation of cell death, plays a significant role in multiple pathological processes associated with liver diseases, including ALF. Several studies have demonstrated that mesenchymal stem cells (MSCs) have promising therapeutic potential in the treatment of ALF. This study aims to investigate the positive effects of MSCs against ferroptosis in an ALF model and explore the underlying molecular mechanisms of their therapeutic function. Our results show that intravenously injected MSCs protect against ferroptosis in ALF mouse models. MSCs decrease iron deposition in the liver of ALF mice by downregulating hepcidin level and upregulating FPN1 level. MSCs labelled with Dil are mainly observed in the hepatic sinusoid and exhibit colocalization with the macrophage marker CD11b fluorescence. ELISA demonstrates a high level of IGF1 in the CCL 4+MSC group. Suppressing the IGF1 effect by the PPP blocks the therapeutic effect of MSCs against ferroptosis in ALF mice. Furthermore, disruption of IGF1 function results in iron deposition in the liver tissue due to impaired inhibitory effects of MSCs on hepcidin level. Our findings suggest that MSCs alleviate ferroptosis induced by disorders of iron metabolism in ALF mice by elevating IGF1 level. Moreover, MSCs are identified as a promising cell source for ferroptosis treatment in ALF mice.

Managing a Prospective Liver Transplant Recipient on the Waiting List

The management of a patient in the peri-transplantation period is highly challenging, and it is even more difficult while the patient is on the transplantation waitlist. Keeping the patient alive during this period involves managing the complications of liver disease and preventing the disease's progression. Based on the pre-transplantation etiology and type of liver failure, there is a difference in the management protocol. The current review is divided into different sections, which include: the management of underlying cirrhosis and complications of portal hypertension, treatment and identification of infections, portal vein thrombosis management, and particular emphasis on the management of patients of hepatocellular carcinoma and acute liver failure in the transplantation waitlist. The review highlights special concerns in the management of patients in the Asian subcontinent also. The review also addresses the issue of delisting from the transplant waitlist to see that futility does not overtake the utility of organs. The treatment modalities are primarily expressed in tabular format for quick reference. The following review integrates the vast issues in this period concisely so that the management during this crucial period is taken care of in the best possible way.

Latest progress in low-intensity pulsed ultrasound for studying exosomes derived from stem/progenitor cells

Stem cells have self-renewal, replication, and multidirectional differentiation potential, while progenitor cells are undifferentiated, pluripotent or specialized stem cells. Stem/progenitor cells secrete various factors, such as cytokines, exosomes, non-coding RNAs, and proteins, and have a wide range of applications in regenerative medicine. However, therapies based on stem cells and their secreted exosomes present limitations, such as insufficient source materials, mature differentiation, and low transplantation success rates, and methods addressing these problems are urgently required. Ultrasound is gaining increasing attention as an emerging technology. Low-intensity pulsed ultrasound (LIPUS) has mechanical, thermal, and cavitation effects and produces vibrational stimuli that can lead to a series of biochemical changes in organs, tissues, and cells, such as the release of extracellular bodies, cytokines, and other signals. These changes can alter the cellular microenvironment and affect biological behaviors, such as cell differentiation and proliferation. Here, we discuss the effects of LIPUS on the biological functions of stem/progenitor cells, exosomes, and non-coding RNAs, alterations involved in related pathways, various emerging applications, and future perspectives. We review the roles and mechanisms of LIPUS in stem/progenitor cells and exosomes with the aim of providing a deeper understanding of LIPUS and promoting research and development in this field.

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.