End-Stage Liver Disease (ESLD) is the terminal stage of the disease in which the liver is severely failing, and its pathological features are mainly irreversible destruction of liver tissue structure and progressive loss of function. The main causes of the disease include chronic viral hepatitis (hepatitis B/C virus infection), alcoholic cirrhosis and advanced progression of metabolism-related fatty liver disease. With increasing liver fibrosis, the liver gradually loses its normal physiological functions, eventually leading to a series of serious complications such as portal hypertension and hepatic encephalopathy. Among the traditional treatments, liver transplantation is the only treatment that can fundamentally resolve end-stage liver disease. However, the severe shortage of donor livers, the high cost of surgery, and postoperative immune rejection have greatly limited the clinical application of this therapy.
In recent years, mesenchymal stem cell (MSCs) therapy has brought new hope for the treatment of end-stage liver disease. Numerous studies have shown that MSCs can play a therapeutic role by secreting exosomes (EVs), which are capable of delivering a variety of biologically active molecules (e.g., proteins, mRNAs, etc.) to promote hepatocyte regeneration and improve the hepatic microenvironment. Currently, clinical studies have focused on the direct infusion of MSCs, while relatively few studies have been conducted on cell-free therapy based on MSC-EVs, but the former has potential carcinogenic risks. It has been demonstrated that a variety of effector molecules contained in MSC-EVs can improve liver function by regulating hepatic stellate cell activation, promoting hepatocyte proliferation and other mechanisms. The project systematically collated the effectors of MSC-derived exosomes (MSC-EVs) and their related signalling pathways reported in existing studies, and selected effector molecules with synergistic effects to engineer the exosomes, thus providing new research ideas for developing safer and more effective therapeutic strategies for end-stage liver disease (ESLD).
Exosomes secreted by human umbilical cord mesenchymal stem cells (hUC-MSCs), as one of the most researched exosome types used to ameliorate end-stage liver disease, have been the subject of a number of studies that have elucidated the mechanism of action of multiple effectors in exosomes to improve hepatic status. Among them, both miR-455-3p and miR-148a-5p have been shown to reverse the process of liver fibrosis by inhibiting hepatic stellate cell activation [8,9]. Although single effector overexpression has been shown to enhance the therapeutic efficacy of exosomes, there is a lack of systematic studies on the changes in therapeutic efficacy following simultaneous increase in the levels of multiple effector molecules in exosomes, especially the possible synergistic effect of miR-455-3p and miR-148a-5p. We would like to construct and optimize an engineered exosome based on the synergistic effect of dual miRNAs (miR-455-3p and miR-148a-5p) and systematically evaluate its interventional effect on liver fibrosis, so as to provide experimental basis and theoretical foundation for the development of a new strategy of highly effective and multi-targeted liver fibrosis treatment.
In addition, curing end-stage liver disease has a significant impact on the family and society, and for the family it is a fundamental liberation. Firstly, the patient himself is given a new lease of life, and the breadwinner of the family is able to regain his ability to work, thus avoiding the interruption of the family's main source of income. Secondly, the huge medical expenses (such as liver transplantation and long-term hospitalisation), which are the main reasons for families to "fall into poverty and return to poverty due to illness", will be completely relieved of this devastating economic burden. Finally, family members will be relieved from the burden of long-term, high-pressure care and mental anguish, and family relationships will return to normal, regaining hope and a sense of well-being. For society, it is of great significance. Firstly, it directly reduces the financial pressure on the public health system and saves valuable medical resources (e.g. ICU beds, organ donors). Secondly, it allows labour to return to the market, transforming patients from patients who consume social resources to value-creating workers, contributing directly to economic development. Third, it greatly reduces the burden on the social assistance and welfare system. This is not only a breakthrough in medicine, but also significantly improves the overall health and productivity of society and promotes social harmony and stability.
In conclusion, curing end-stage liver disease means saving countless families in distress and bringing enormous health benefits and economic value to the society, which is of far-reaching significance, and we should all work hard to achieve this goal.
Liver Transplantation: This is currently the only method that can cure ESLD at its root and significantly prolong the long-term survival of patients. A healthy, functioning donor liver is surgically transplanted into the patient to replace the function of the diseased liver. It is the "gold standard" of treatment for end-stage liver disease.
Today, the treatment of end-stage liver disease faces many challenges.
1.The shortage of liver sources is the biggest bottleneck facing liver transplantation. The number of donor livers is far less than the number of patients waiting for transplantation, resulting in many patients dying while waiting. Living donor liver transplantation partially relieves the pressure, but there are donor risks and strict medical ethical restrictions.
2.The technical bottleneck cannot be broken through. The function of the artificial liver system is still imperfect, unable to synthesise key substances such as albumin and coagulation factors, with limited support time, and the efficacy of treatment needs to be further improved.
3.The complexity of the disease itself: ESLD patients are often accompanied by systemic multi-organ functional impairment, physical weakness, and poor tolerance of surgery. Liver transplantation itself is technically difficult and risky, and after the operation, patients need to take immunosuppressants for life to prevent rejection, and face long-term risks such as infections, tumour recurrence and drug side effects.
4.Many patients are diagnosed when they are already in the terminal stage, missing the best time for antiviral, alcohol cessation and other etiological treatments, with a narrow therapeutic window and limited results.
In conclusion, liver transplantation is the hope for cure but is limited by the source of liver; artificial liver and medical treatment are important life-supporting tools but have limitations. Future breakthroughs depend on improved organ donation systems, development of new artificial livers, regenerative medicine technologies such as hepatocyte transplantation, and more effective early intervention strategies.
The overall objective of this study is to construct and optimize an engineered exosome based on the synergistic effects of dual miRNAs (miR-455-3p and miR-148a-5p), and to systematically evaluate its therapeutic efficacy in liver fibrosis. This work aims to provide experimental evidence and a theoretical foundation for developing an efficient, multi-target therapeutic strategy against liver fibrosis.
1.Successfully construct engineered human umbilical cord mesenchymal stem cell-derived exosomes (hUC-MSC-Exos) individually loaded with miR-455-3p and miR-148a-5p.
2.Determine the inhibitory effects of the two engineered exosomes—when applied individually or in different combination ratios—on the proliferation, activation, and extracellular matrix secretion of activated hepatic stellate cells (HSCs).
3.Using an in vitro liver fibrosis model, verify and identify the optimal combination ratio of the dual-miRNA engineered exosomes that achieves the strongest anti-fibrotic effect.
