The immediate early gene of human cytomegalovirus stimulates vascular smooth muscle cell proliferation in vitro and in vivo

Cytomegalovirus (CMV) infection has been carefully studied regarding the relationship with the vascular smooth muscle cell (VSMC) proliferation in either atherosclerosis or post-angioplasty restenosis, but its role in the vessel wall has yet to be elucidated. To clarify the pathogenic ability of CMV in the vessel wall, we transduced the immediate early (IE) gene of CMV into the VSMCs and endothelial cells (ECs) by hemagglutinating virus of Japan-liposome method. The in vitro IE gene transfer demonstrated that the conditioned medium of IE gene transferred ECs enhanced [3H]-thymidine uptake of VSMCs. The enhanced proliferation of the IE gene transferred VSMCs was observed after the stimulation by basic fibroblast growth factor. The in vivo IE gene transfer showed neointimal thickening while the control arteries did not. These findings thus suggest that the expression of CMV-IE gene in the vessel wall may play a role in the fibrocellular neointimal formation or progression of atherosclerosis in vivo.

Inflammatory cytokines cause coronary arteriosclerosis-like changes and alterations in the smooth-muscle phenotypes in pigs

We recently developed a porcine model in which chronic, local treatment with interleukin-1 beta (IL-1 beta) causes coronary arteriosclerosis-like changes and hyperconstrictive responses. This study was designed to examine whether or not other major inflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) might also cause similar coronary responses and whether those responses are associated with alterations in the smooth-muscle phenotypes. A segment of the porcine coronary artery was aseptically wrapped with cotton mesh, absorbing IL-1 beta, TNF-alpha, and IL-1 alpha. Two weeks after the operation, coronary arteriography showed the development of mild stenotic lesions at the cytokine-treated sites, where hyperconstrictive responses were repeatedly induced by intracoronary serotonin or histamine. Histologically mild intimal thickening was noted at those cytokine-treated sites. Immunostaining and immunoblotting demonstrated that all three myosin heavy chain isoforms, SM1, SM2 (smooth-muscle type), and SMemb (nonmuscle type), were noted in the normal coronary segments, whereas in the segments treated with inflammatory cytokines, SM1 and SM2 were markedly reduced, and only SMemb was noted. These results indicate that inflammatory cytokines all have a similar ability to induce coronary arteriosclerosis-like changes and hyperconstrictive responses, which are associated with alterations in smooth-muscle phenotypes toward dedifferentiation.

Characterization of in vivo gene transfer into the arterial wall mediated by the Sendai virus (hemagglutinating virus of Japan) liposomes: an effective tool for the in vivo study of arterial diseases

Recently, much attention has been paid to the arterial gene transfer technique using several vector systems. In the present study, we experimentally examined the transfection efficiency of the exogenous gene, the duration of gene expression, and the cytotoxic effect of the hemagglutinating virus of Japan (HVJ) liposome on the intact arterial wall to evaluate its effectiveness for the study of arterial diseases. To evaluate the transfection efficiency and duration of gene expression, pSV beta-galactosidase was transferred into the carotid arterial wall of rabbits. The cytotoxic effect of HVJ liposomes on the vascular cell components was also evaluated by a neutral red assay in vitro and scanning electron microscopy in vivo. HVJ liposomes could achieve highly efficient gene transfection into the medial smooth muscle cells of intact arteries at 150 and 760 mmHg of pressure (mean = 85.3% and 93.5% of total smooth muscle cells, respectively) without any inflammatory reaction. The introduced exogenous gene was expressed for at least 14 days. In addition, the cytotoxicity for the arterial smooth muscle cells and endothelial cells induced by HVJ liposome vehicles at routinely used concentrations (5,000 to 10,000 hemagglutinating activity units/ml) was minimal both in vitro and in vivo. As an example, we introduced human vascular endothelial growth factor cDNA, which was driven with cytomegalovirus enhancer and beta-actin promoter, into the rabbit carotid arteries, and it induced not only angiomatoid proliferation of endothelial cells forming irregular vascular channels but also intimal hyperplasia. Based on these findings, we conclude that HVJ liposome-mediated arterial gene transfer is a highly efficient, noninvasive, and effective gene delivery method for the study of vascular disorders.

In situ detection of frequent and active infection of human cytomegalovirus in inflammatory abdominal aortic aneurysms: possible pathogenic role in sustained chronic inflammatory reaction

Inflammatory abdominal aortic aneurysm (IAAA) is histopathologically characterized by extensive adventitial fibrosis, mononuclear cell infiltration with lymph follicle formation, and severe atheromatous changes in the aneurysmal wall. We previously reported a frequent prevalence and immediate early gene expression of human cytomegalovirus (CMV) in IAAA by solution-phase PCR and reverse transcription PCR, respectively, and suggested that this virus might play a role in chronic inflammatory reaction in IAAA. To evaluate the pathogenic role of CMV infection, the frequency and distribution of CMV infected cells in IAAA were examined by in situ PCR, and compared with those in atherosclerotic aneurysms (AA) and control cases with minimal atherosclerotic changes. Human leukocyte antigen (HLA)-DR was simultaneously evaluated as a marker for immune response related to CMV infection. Immediate early gene expression was also detected by reverse transcription PCR and in situ hybridization, to certify whether the CMV infection in IAAA is active or latent. In the fibrously thickened adventitia of IAAA, CMV infected cells and HLA-DR-positive cells were more frequently encountered than in that of AA and control cases (p < 0.01). CMV infected cells were largely identified as macrophages, fibroblasts, endothelial cells, and lymphocytes. The expression of CMV immediate early mRNA, which suggests an active infection inducing active inflammatory reaction, was detected in most of the macrophages, endothelial cells, and fibroblasts. Our results strongly suggest that frequent and active infection of CMV in IAAA plays a significant role in the induction and acceleration of chronic inflammatory reaction in aortas of IAAA.

Portal vein thrombosis due to antithrombin III deficiency. A case report

The authors report a case of intrahepatic portal vein thrombosis in a sixty-four-year-old Japanese man with antithrombin III deficiency who successfully underwent cholecystectomy and common bile duct exploration. To their knowledge, this is the first report of portal vein thrombosis due to primary antithrombin III deficiency.