Background/Aims: Liver resection represents the treatment of choice for hepatocellular carcinoma (HCC) arising in well-compensated cirrhosis. Gene expression of the multifunctional cytokine, Oncostatin M (OSM), stimulates liver regeneration and adenoviral vector expressing OSM (AdOSM) allows a persistent expression of the gene. The aim of this study is to evaluate the benefits of the preoperative injection of AdOSM to the remnant lobes to regenerate the liver. Methods: A 70% partial hepatectomy was performed in dimethylnitrosamine-administrated cirrhotic rats with a preoperative injection of AdOSM, adenoviral vector carrying β-galactosidase (AdLacZ), or phosphate-buffered saline (PBS). The morphologic, histologic, and biochemical changes in the remnant liver and survival rates were then assessed. Results: Portal injection with clamping the portal branches of the resected lobes for 5 min made it possible to effectively transduce the adenoviral vector into the remnant lobes. The ratio of the remnant liver weight/body weight (%) was 2.3 ± 0.5 in the AdOSM group, 1.1 ± 0.3 in the AdLacZ group (p < 0.001), and 1.6 ± 0.4 in the PBS group (p = 0.02). The fibrous ratio (%) was 21.3 ± 4.6 in the AdOSM group and 35.2 ± 4.5 in the AdLacZ group on day 4 after hepatectomy and fibrous status was significantly decreased in the AdOSM group (p = 0.02). Serum hyaluronic acid which is the indicator of liver fibrosis was 215 ± 141 ng/mL in the AdOSM group and 1963 ± 1225 ng/mL in the AdLacZ group (p = 0.03). Conclusions: The OSM gene therapy may increase the possibility of hepatectomy in a cirrhotic liver by improving fibrosis, hepatic function, and hepatocyte regeneration.
Although recent demonstrations of satisfactory results of nonsurgical procedures such as percutaneous ethanol injection (PEI), radiofrequency ablation (RFA), and transcatheter arterial chemoembolization (TACE), liver resection still plays an important role in treatment of Hepatocellular carcinoma (HCC) [
Previously administration of hepatocyte growth factor (HGF) was aimed to support liver regeneration for the cirrhotic partial hepatectomy models and showed preferable regeneration effects [4,5]. However, HGF itself has a potential to induce cancer growth or hepatocarcinogenesis and which were the subject to be settled.
On costatin M (OSM), a pleiotropic glycoprotein cytokine that was originally purified from the conditioned media of phorbol ester stimulated U937 (histocytic lymphoma) cells, is related structurally and functionally to the subfamily of neurotrophic cytokines known as the interleukin-6 (IL-6) [
In the liver, the OSM stimulates the expression of acute phase proteins and tissue inhibitor of metalloproteinase-1 (TIMP-1) [
In general the cytokines are rapidly turned over, therefore continuous dosage are needed to keep its biological activity. To overcome the problem, several vectors including naked plasmid, liposome and adenoviral vector have been used [
The recombinant human adenovirus type 5 is frequently used for in vivo gene therapeutic applications. This virus infects a range of dividing and non dividing cells very efficiently and has an affinity to liver tissue in particular. Although adenovirus-related toxicity remains major concerns [
In this study, we evaluated the benefits of the preoperative injection of adenoviral vector expressing the OSM (AdOSM) to the remnant lobe to accelerate its regeneration following hepatectomy.
During all the following experimental procedures, the animals were treated in accordance with Japanese Government Animal Protection and Management Law (No. 105), Japanese Government Notification on Feeding and Safekeeping of Animals (No. 6), the Guidelines for Animal Experiments of Wakayama Medical University, and the NIH Guide for the Care and Use of Laboratory Animals (Institute of Laboratory Animal Resources, National Research Council).
Seven-week-old male, Sprague-Dawley rats that weighed 200 to 250 g were purchased (Kiwa Jikken, Wakayama, Japan) and fed a nutritionally balanced rodent diet and water ad libitum. Liver fibrosis was induced by the intraperitoneal injections of 1% dimethylnitrosamine (DMN) (Nacalai tesque, Kyoto, Japan) dissolved in saline at 1 mL/kg body weight for 3 consecutive days per week for 3 weeks, which showed a pseudolobular formation that was similar to the characteristic pathologic changes found in liver cirrhosis in humans [
E1-and E3-region-deleted replication defective adenoviral vectors expressing either human OSM (AdOSM) or β-galactosidase (AdLacZ) under a CA promoter (comprising a cytomegalovirus enhancer and chicken betaactin promoter) were obtained from the RIKEN Bio Resource Center (Tukuba, Japan). These vectors were propagated with 293 cells (Japan Collection of Research Bioresources, Osaka, Japan), which were human embryonic kidney cells transformed by the E1A and E1B genes. The viruses were purified twice with cesium chloride equilibrium centrifugation, then were dialyzed against phosphate buffered saline (PBS) with 10% glycerol, and titrated with 293 cells. Both viral titers of AdLacZ and AdOSM were 5.0 × 108 plaque forming unit (PFU)/mL. To confirm the expression of OSM or LacZ gene, HeLa cells (Japan Collection of Research Bioresources, Osaka, Japan) were cultured with the transduction of AdOSM or AdLacZ, as previously described [