Gene transfer for experimental saccular aneurysms.

SUMMARY: Reinforcing an aneurysmal wall is one possible way to prevent from aneurysm rupture. We preliminarily tried focal gene transfer against the wall of experimental aneurysms to aim the transgene remodeling of aneurysmal wall. Two experimental saccular aneurysms were created on canine common carotid artery with an artificial dissecting method, which resemble clinical aneurysms. Adenovirus vector (AxCALacZ, 10(8) pfu) was slowly injected into the aneurysm cavity for over 30 minutes under the condition of intraaneurysmal flow arrest using balloon-assisted neck-plasty technique. The arteries and aneurysms were evaluated 48 hours after the transduction with X-gal staining, and beta-galactosidase expression was detected mainly in the intima in both cases. No adverse effects on the normal carotid wall and no systemic complications were observed after the procedure. This experimental study suggests the possibility of gene therapy for cerebral aneurysms.

Cationic liposome conjugation to recombinant adenoviral vector reduces viral antigenicity.

Adenoviral (Ad) vectors are commonly used in gene therapy trials because of their efficiency in gene transfer. However, their use is limited by immune responses that reduce transgene expression and decrease the efficacy of repeated vector administration. In this study, we demonstrated that conjugation of Ad vector with our novel cationic liposomes could reduce viral antigenicity in vivo. Mice subcutaneously injected with liposome-conjugated Ad vector showed a 6.5-fold reduction of anti-Ad antibodies with neutralizing activity, compared to those with unconjugated Ad vector. Interestingly, we also found that the conjugated vector is less susceptible to inactivation by neutralizing antibodies in vitro and in vivo. Our results suggest that liposome conjugation reduces viral antigenicity, shields vectors from neutralizing antibody, and may allow repeated Ad vector administration.

Transduction efficiency of adenoviral vectors into human glioma cells increased by association with cationic liposomes.

Replication-deficient adenoviral vectors are promising agents for human gene therapy of the greater transduction efficiency than other vectors. However, there are distinct disadvantages, including high immunogenicity, which limits the administration to human organs, particularly the brain. Injection of adenoviral vectors into the human brain causes inflammatory responses and induces cerebral edema. The combined effect of adenoviral vectors and cationic liposomes in vitro was investigated in an effort to reduce the immune reaction against the antigens of adenoviral vectors. No toxicity of adenoviral vector-associated liposomes was observed within optimal lipid concentration. The transduction efficiency of the adenoviral vectors containing the beta-galactosidase gene increased almost 10-fold when associated with the cationic liposomes. Furthermore, greater cytotoxicity was induced when the adenoviral vector containing herpes simplex virus-thymidine kinase gene was combined with cationic liposomes than with only the adenoviral vector. These results suggest that the combination of adenoviral vectors and cationic liposomes allows the doses of adenoviral vectors to be reduced while maintaining transduction efficiency.

Antitumor effect and cellular immunity activation by murine interferon-beta gene transfer against intracerebral glioma in mouse.

Cationic liposomes containing the human interferon-beta (IFN-beta) gene induce marked growth inhibition in human glioma cells. In vivo experiments using an human glioma implanted into the brains of nude mice have demonstrated a definite growth-inhibitory effect, achieving complete tumor regression with multiple intratumoral injections of the gene. However, nude mouse studies are inadequate to evaluate antitumor effects fully, especially those related to activation of the host immune response. This article aimed to investigate antitumor effects and immune response activation by murine IFN-beta gene transfer in syngeneic mice. In vitro experiments demonstrated a stronger growth-inhibitory effect of liposomes containing the murine IFN-beta gene on a GL261 mouse glioma cell line than exogenously added murine IFN-beta. In in vivo experiments, intratumoral administration of liposomes containing the murine IFN-beta gene resulted in a 16-fold reduction in the mean volume of residual gliomas in the brains of C57BL/6 mice and massive infiltration of cytotoxic T lymphocytes (CTL) within the residual tumor, while few CTL were infiltrated in controls including murine IFN-beta, empty liposomes, naked plasmid expressing murine IFN-beta, and liposomes containing beta-galactosidase gene. In addition, 40% of mice treated with liposomes containing the murine IFN-beta gene were completely cured. These findings indicated that activation of cellular immunity participates in antitumor effects in vivo together with direct effects of the IFN-beta gene.

[Cranioplasty using cryopreserved autogenous bone].

Various materials and methods can be used for cranioplasty following external decompression craniotomy. We generally use cryopreserved autogenous bone for cranioplasty following external decompression. We assessed several factors, including histological changes in the stored bone, postoperative skull X-ray changes, postoperative changes in skull morphology, and the incidence of postoperative infections. The purpose of this study was determined if our materials and preservation methods were appropriate. The subjects were 110 patients who underwent cranioplasty using cryopreserved autogenous bone following external decompression at our hospital. They were followed up for at least one year. Bone fragments removed at the time of external decompression were stored at -40 degrees C an ultra-low temperature freezer and returned to room temperature before using them for cranioplasty. Follow-up skull x-ray films were obtained for 1-10 years postoperatively. Almost all of the 46 patients showed bone union at least one year after cranioplasty, but seven patients (15%) had marked bone resorption and bone atrophy after 3 years or longer. Five of these patients had a concomitant ventriculo-peritoneal shunt. Two of them developed collapse of the skull due to bone resorption, and this was considered to have been influenced by the shunt. Epidural empyema occurred postoperatively in five patients (4.5%), and staphylococci were the causative organisms in all five cases. The infections were completely cured by removal of the bone graft, debridement of the wound, and epidural drainage. Cranioplasty following external decompression craniotomy using cryopreserved autogenous bone fragments is a simple procedure, and the materials are inexpensive. Many of our patients who underwent cranioplasty using cryopreserved autogenous bone experienced no serious complications.(ABSTRACT TRUNCATED AT 250 WORDS)