Therapeutic efficacy and in vivo distribution of human umbilical cord-derived mesenchymal stem cell spheroids transplanted via B-Ultrasound-guided percutaneous portal vein puncture in rhesus monkey models of liver fibrosis

Abstract

Background Liver fibrosis can progress to end-stage cirrhosis and liver cancer. Mesenchymal stem cells (MSCs) were considered the most promising therapeutic strategy, but most of the MSCs injected intravenously traditionally are trapped in the lungs, rapidly reducing their survival ability. MSC spheroids cultured in 3D have shown higher tolerance to fluid shear stress and better survival than dissociated MSCs. Simulating the route of orthotopic liver transplantation, transplanting MSC spheroids into the liver via hepatic portal vein may impact superior therapeutic effects. Methods In the present study, human umbilical cord-derived MSC spheroids (hUC-MSCsp) were transplanted into rhesus monkey models of liver fibrosis via B-ultrasound-guided percutaneous portal vein puncture with minimized body invasion. The therapeutic effect is evaluated through hematology, ultrasound, and pathology. To study the effect of hUC-MSCsp on gene expression in rhesus monkeys with liver injury, transcriptome sequencing analysis was performed on the livers of rhesus monkeys. The distribution of transplanted hUC-MSCsp was traced with RNA scope technology. Results We found that hUC-MSCsp significantly restored liver function, including ALT, AST, ALB, GLOB and bilirubin. hUC-MSCsp also significantly reduced liver collagen deposition and inflammatory infiltration, and promote dismission

1. Introduction

Liver fibrosis is a fibrogenic and inflammatory process resulting from hepatocyte injury, characterized by subsequent hepatic architectural distortion and resultant loss of liver function [1]. The primary pathophysiology underlying liver fibrosis involves increased deposition of type I and III collagen in the extracellular matrix (ECM) [2]. Currently, liver fibrosis affects approximately 500 million individuals worldwide, and if left untreated, it can progress to irreversible end-stages such as liver cirrhosis or hepatocellular carcinoma [3]. Liver cirrhosis may give rise to various complications including ascites and hepatic encephalopathy. Therefore, early intervention in liver fibrosis is crucial for preventing the development of liver cirrhosis [4, 5]. Although orthotopic liver transplantation is currently considered the most efficacious therapeutic approach, its clinical application remains limited due to organ donor scarcity, exorbitant costs, and requirement for lifelong immunosuppression [6]. Consequently, there is an urgent need for alternative therapeutic approaches and regenerative strategies in the treatment of liver fibrosis.

The transplantation of mesenchymal stem cells (MSCs) has emerged as the most promising therapeutic approach for liver fibrosis considering recent advancements in regenerative medicine [7–9]. Many studies have explored the mechanisms of MSCs in treating liver fibrosis from different perspectives. MSCs may differentiate into hepatocytes or fuse with existing hepatocytes after being introduced into damaged liver tissue [10]. Moreover, MSCs can facilitate the regeneration of damaged liver tissue by producing various cytokines, growth factors, and extracellular vesicles [11], but the precise mechanism underlying the therapeutic effect of MSCs on liver fibrosis remains elusive. Despite the favorable therapeutic effects demonstrated by MSCs in liver fibrosis [12], further investigation is required to understand their distribution and homing mechanisms in vivo before their widespread clinical application. In our previous study, we observed that one hour after intravenous infusion of MSCs into healthy monkeys, MSCs primarily localized in lungs and heart, with limited cell presence in liver [13]. A major challenge for clinical application of MSCs lies in their low homing efficiency. Considering that liver transplantation typically involves injecting through human portal vein [14], we speculate that transplanting MSCs via hepatic portal vein may enhance their retention within the liver and improve therapeutic efficacy. Moreover, traditional 2D monolayer-cultured MSC therapy has limitations, including reduced cell viability and functionality upon transplantation.