Administration of rhHGF-activator via portal vein stimulates the regeneration of cirrhotic liver after partial hepatectomy in rats

BACKGROUND/AIMS: Cirrhotic liver has less ability to regenerate than normal liver, but it can produce the precursor of hepatocyte growth factor (proHGF) similarly to normal liver after resection. Studies were performed to examine whether the exogenous administration of recombinant human (rh) HGF-activator converts proHGF to biologically active (mature) HGF, inducing an enhancement of liver regeneration in cirrhosis. MATERIALS AND METHODS: Rats with liver cirrhosis were treated by 45% partial hepatectomy, and rhHGF-activator or vehicle was injected via the portal vein 24 h after resection. Liver injury and its regeneration, the conversion of proHGF to mature HGF, and the activation of its signal through HGF receptor (c-Met) were analyzed. RESULTS: rhHGF-activator improved the recovery of liver function after resection in cirrhotic liver as compared with the control group. rhHGF-activator also enhanced the proliferating cell nuclear antigen labeling index and liver regeneration rate. rhHGF-activator converted the proHGF to mature HGF, showing the maximal effect at 10 min after injection, which was followed by tyrosine phosphorylation of insulin receptor substrate (IRS)-1, and the association of IRS-1 with c-Met and phosphatidylinositol 3-kinase. CONCLUSIONS: Results demonstrate that the administration of rhHGF-activator stimulates the recovery of liver function and regeneration after resection in cirrhotic liver through the activation of proHGF and its intracellular signal. It may be potentially useful treatment for patients with liver cirrhosis.     

Platelet-derived growth factor expression correlates with tumor grade and proliferative activity in human oligodendrogliomas

Background

For the last one and a half decade, it has been found that platelet-derived growth factor (PDGF) promotes glial tumor growth through autocrine and paracrine loops, by expression of PDGFα receptor (PDGFRα) on glioma cells and PDGFβ receptor (PDGFRβ) on proliferating endothelial cells. However, studies on oligodendrogliomas, correlating expression of PDGF and its receptor with tumor grade and proliferative activity, through MIB-1 labeling index (LI) are relatively few as compared to astroglial counterpart.

Methods

Formalin-fixed paraffin-embedded tissues from 55 cases of oligodendrogliomas (34 World Health Organization [WHO] grade II and 21 WHO grade III tumors) were subjected to immunohistochemistry. MIB-1 LI was calculated, and a semiquantitative scoring system for expression of PDGF and PDGFRα was used.

Results

MIB-1 LI and PDGF expression increased with histologic grades of malignancy (“t” test, P < .001 and Mann Whitney test, U = 109, P < .001 respectively). The PDGF expression scores had a positive correlation with MIB-1 LI, irrespective of tumor grade (Pearson's correlation coefficient, r = 0.566; P < .001). However, there was no significant difference of PDGFRα expression between 2 grades of tumors.

Conclusions

The results of this study showed that MIB-1 LI is a rapid and cost-effective modality for predicting tumor grade in oligodendrogliomas. Immunohistochemistry for PDGF was found to be useful in differentiating various grades of oligodendroglioma, and therefore, it may be involved in tumor cell proliferation and malignant transformation. Platelet-derived growth factor receptor α, although expressed in oligodendroglial neoplasms, was not found to be useful in predicting tumor grade.     

Fetal mesenchymal stem cells ameliorate acute lung injury in a rat cardiopulmonary bypass model

Background

Systemic inflammation after prolonged cardiopulmonary bypass (CPB) can cause serious multiorgan system dysfunction. Mesenchymal stem cells (MSCs) are reported to reduce inflammation and attenuate immune response. We have focused on fetal membrane (FM) as a source to provide a large number of MSCs (FM-MSCs). Allogeneic administration of FM-MSCs has been reported to mitigate autoimmune myocarditis or glomerulonephritis. The aim of this study was to investigate whether allogeneic FM-MSCs attenuate systemic inflammatory responses and lung injury in a rat CPB model.

Stem cell engraftment and survival in the ischemic heart

Cellular therapy has emerged as a potentially novel treatment for severe ischemic heart disease, and there is increasing evidence that stem cell transplantation may improve the perfusion and contractile function of ischemic myocardium. However, the problem of poor donor cell engraftment and survival in ischemic myocardium limits the successful use of cellular therapy for treating ischemic heart disease. This review discusses the state-of-the-art understanding of the low level of cell engraftment and cell survival after transplantation into the ischemic heart, with a focus on the approaches that have been investigated for supporting and improving the survival and engraftment of transplanted cells in this setting.