The use of bone morphogenetic protein—6 gene therapy for percutaneous spinal fusion in rabbits

2004 ◽  
Vol 1 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Jeffrey J. Laurent ◽  
K. Michael Webb ◽  
Elisa J. Beres ◽  
Kevin McGee ◽  
Jinzhong Li ◽  
...  
Keyword(s):  
Gene Therapy ◽  
New Zealand ◽  
Spinal Fusion ◽  
Ct Scanning ◽  
Content Type ◽  
Morphogenetic Protein ◽  
New Zealand White Rabbits ◽  
Percutaneous Administration ◽  
Multiple Levels ◽  
Fine Print

Object. Fusion procedures in the lumbar spine have been performed in the US since 1911. Since that time, the indications and techniques for spinal fusion have evolved. Despite technical advancements, spinal fusion remains a major operation, and fusion nonunion rates of up to 35% are still reported. In this study, the authors were able to induce intertransverse process fusions in immune-competent New Zealand White rabbits by percutaneous administration of an adenoviral vector containing the bone morphogenetic protein (BMP-6) gene (Ad-BMP-6). The results represent an important step forward in finding new methods to increase the success and decrease the morbidity associated with spinal fusion. Methods. Five New Zealand White rabbits were used. Injection of the adenoviral construct was performed at multiple levels (bilaterally) in each animal while using fluoroscopic guidance. Injection consisted of either Ad-BMP-6 or Ad—β-galactosidase (β-gal) (control). Because multiple levels were injected, each animal served as an internal control. The animals underwent postinjection computerized tomography (CT) scanning at 7 and 14 weeks. After undergoing final CT scanning, the animals were killed and the spines were harvested. The fusion sites were analyzed by gross inspection, histopathological methods, and micro—CT studies. Conclusions. The results of this study show that an anatomically precise fusion can be accomplished by percutaneous administration of gene therapy. The next step in these studies will be extension of the technique to nonhuman primates and eventually to human clinical studies.

Percutaneous spinal fusion using bone morphogenetic protein-2 gene therapy

1999 ◽  
Vol 90 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Tord D. Alden ◽  
Debra D. Pittman ◽  
Elisa J. Beres ◽  
Gerald R. Hankins ◽  
David F. Kallmes ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Bone Formation ◽  
Spinal Fusion ◽  
Bone Morphogenetic Protein 2 ◽  
Cmv Promoter ◽  
Content Type ◽  
Morphogenetic Protein ◽  
Adenoviral Construct ◽  
Fine Print

Object. Gene therapy has many potential applications in neurosurgery. One application involves bone morphogenetic protein-2 (BMP-2), a low-molecular-weight glycoprotein that induces bone formation in vivo. Numerous studies have demonstrated that the BMP-2 protein can enhance spinal fusion. This study was undertaken to determine whether direct injection of an adenoviral construct containing the BMP-2 gene can be used for spinal fusion. Methods. Twelve athymic nude rats were used in this study. Recombinant, replication-defective type 5 adenovirus with the cytomegalovirus (CMV) promoter and BMP-2 gene (Ad-BMP-2) was used. A second adenovirus constructed with the CMV promoter and β-galactosidase (β-gal) gene (Ad-β-gal) was used as a control. In three groups (four rats each) 7.5 µl of virus (5 × 108 particles/µl) was injected percutaneously and paraspinally at the lumbosacral junction: Group 1 received Ad-BMP-2 bilaterally; Group 2 received Ad-BMP-2 on the right, Ad-β-gal on the left; and Group 3 received Ad-β-gal bilaterally. Computerized tomography (CT) scans of the lumbosacral spine were obtained at 3, 5, 8, and 12 weeks. At 12 weeks, the animals were killed and underwent histological inspection. Ectopic bone formation was observed both on three-dimensionally reconstructed CT scans and histological examination in all rats at sites treated with Ad-BMP-2. Histological analysis demonstrated bone at different stages of maturity adjacent to the spinous processes, laminae, and transverse processes. Conclusions. Results of this study clearly demonstrated that it is possible to produce in vivo endochondral bone formation by using direct adenoviral construct injection into the paraspinal musculature, which suggests that gene therapy may be useful for spinal fusion in the future.

Murine spinal fusion induced by engineered mesenchymal stem cells that conditionally express bone morphogenetic protein—2

2005 ◽  
Vol 3 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Amir Hasharoni ◽  
Yoram Zilberman ◽  
Gadi Turgeman ◽  
Gregory A. Helm ◽  
Meir Liebergall ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Spinal Fusion ◽  
Genetically Engineered ◽  
Bone Morphogenetic Protein 2 ◽  
Content Type ◽  
Histological Studies ◽  
Morphogenetic Protein ◽  
Fine Print

Object. The authors hypothesized that spinal fusion can be achieved and monitored by using cell-mediated gene therapy. Mesenchymal stem cells (MSCs) genetically engineered to express recombinant human bone morphogenetic protein—2 (rhBMP-2) conditionally, were implanted into the paraspinal muscles of mice to establish spinal fusion. The goal was to demonstrate an MSC-based gene therapy platform in which controlled gene expression is used to obtain spinal fusion in a murine model. Methods. Mesenchymal stem cells expressing the rhBMP-2 gene were injected into the paravertebral muscle in mice. Bone formation in the paraspinal region was longitudinally followed by performing micro—computerized tomography scanning, histological studies, and an analysis of osteocalcin expression to demonstrate the presence of engrafted engineered MSCs. The minimal period of rhBMP-2 expression by the engineered MSCs required to induce fusion was determined. The results of this study demonstrate that genetically engineered MSCs induce bone formation in areas adjacent to and touching the posterior elements of the spine. This newly formed bone fuses the spine, as demonstrated by radiological and histological studies. The authors demonstrate that injected cells induce active osteogenesis at the site of implantation for up to 4 weeks postinjection. They found that a 7-day induction of rhBMP-2 expression in genetically engineered MSCs was sufficient to form new bone tissue, although the quantity of this bone increased as longer expression periods were implemented. Conclusions. After their injection genetically engineered MSCs can efficiently form new bone in the paraspinal muscle of the mouse to obtain spinal fusion. The extent and quantity of this newly formed bone can be monitored by controlling the duration of rhBMP-2 gene expression.

The intracerebral distribution of BCNU delivered by surgically implanted biodegradable polymers

1992 ◽  
Vol 76 (4) ◽  
pp. 640-647 ◽  
Author(s):  
Stuart A. Grossman ◽  
Carla Reinhard ◽  
O. Michael Colvin ◽  
Mark Chasin ◽  
Robert Brundrett ◽  
...  
Keyword(s):  
New Zealand ◽  
Brain Tissue ◽  
Direct Injection ◽  
Normal Brain ◽  
Local Concentration ◽  
Content Type ◽  
Drug Concentrations ◽  
New Zealand White Rabbits ◽  
The Brain ◽  
Fine Print

✓ The local concentration and distribution of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) within normal brain tissue were studied following surgical implantation of biodegradable polymer containing BCNU in New Zealand White rabbits. Cylindrical discs of poly(bis(p-carboxyphenoxy)-propane:sebacic acid) copolymer in a 20:80 formulation were made containing [3H]-inulin or [3H]-BCNU labeled in the methylene hydrogens of the chloroethyl groups. These were implanted in the brains of 56 New Zealand White rabbits. The animals were sacrificed 3, 7, 14, or 21 days later and the brains were rapidly removed, frozen, and prepared for quantitative autoradiography. Autoradiographs from coronal sections bisecting the polymer were analyzed to determine both the proportion of the brain section exposed to the tracer and the local drug concentrations as a function of distance from the polymer. Tritiated BCNU was also injected directly into the brains of eight additional rabbits, and local brain concentrations were studied over time. The results of this study demonstrate that approximately 50% of the area of the brain sections was exposed to radiolabeled compound 3 days after BCNU-polymer implantation, 15% at 7 days, and less than 10% at 14 and 21 days. Polymer discs containing 600 µg BCNU generated 6 mM concentrations of BCNU in brain tissue 10 mm from the polymer at 3 and 7 days. Pharmacological studies demonstrated that approximately 25% of the tritium label was associated with intact BCNU 3 days following polymer implantation. Radiolabeled inulin delivered by polymer remained dispersed throughout the ipsilateral hemisphere for 14 days. Direct injection of [3H]-BCNU into brain parenchyma resulted in widely distributed tracer at 1 and 3 hours with rapid disappearance thereafter. It is concluded that local delivery of BCNU to brain tissue with this polymeric drug delivery system results in sustained high local concentrations of BCNU which may be of value in the treatment of patients with brain tumors.

The effects of mechanical immobilization on sutural development in the growing rabbit

1980 ◽  
Vol 53 (6) ◽  
pp. 794-801 ◽  
Author(s):  
William J. Foley ◽  
Vincent G. Kokich
Keyword(s):  
New Zealand ◽  
Biological Response ◽  
Bone Union ◽  
Coronal Suture ◽  
Content Type ◽  
Bone Bridge ◽  
Age Related ◽  
New Zealand White Rabbits ◽  
The Brain ◽  
Fine Print

✓ Methyl-2-cyanoacrylate was used to mechanically immobilize the coronal suture unilaterally in a series of New Zealand white rabbits at varying ages. The animals were separated into groups; some were sacrificed at 30 days and some at 60 days postoperatively. Amalgam markers were placed in the parietal and frontal bones across the coronal suture, and were measured immediately after surgery and at the time of sacrifice to confirm mechanical immobility. The animals were studied radiographically and histologically in order to document the presence or absence of sutural bone union. Based on the results of this study, it appears that immobilization of the coronal suture results in the formation of an ectocranial periosteal bone bridge in rabbits less than 8 weeks of age. Bone union was not found in animals older than 8 weeks of age. This age-related difference in response is believed to be due to decreased periosteal depository activity on the ectocranial surface of the calvaria once the brain ceases to expand actively. Furthermore, bone union or synostosis was never seen within or across the internal portion of the sutural ligament. It is suggested, therefore, that sutural immobilization at young ages in the rabbit does not result in sutural synostosis and that the term “periosteal bone bridge” should be used when referring to this biological response.

Experimental craniosynostosis in growing rabbits

1983 ◽  
Vol 58 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Dennis L. Nappen ◽  
Vincent G. Kokich
Keyword(s):  
New Zealand ◽  
The Other ◽  
Coronal Suture ◽  
Content Type ◽  
Metallic Implants ◽  
New Zealand White Rabbits ◽  
Parietal Bones ◽  
Fine Print

✓ Reports on the role of the periosteum in premature sutural synostosis have been contradictory. The present study summarizes a series of six experiments designed to clarify these previously conflicting findings. Twenty-five male New Zealand White rabbits were divided into six experimental groups. In four of the groups, methyl-2-cyanoacrylate was used to glue the frontal and parietal bones together and temporarily immobilize the coronal suture. In the other two groups, the sutures were not immobilized. Polyethylene was used to separate the cyanoacrylate from the periosteum in two of the groups. The experiments were performed at 5 weeks of age, and the animals were killed at either 30, 45, or 180 days postoperatively. Metallic implants were placed in the frontal and parietal bones for monitoring growth and/or sutural immobilization. Sutural fusion was confirmed radiographically or histologically. Based upon the findings it seems that mechanical immobilization of a suture does not induce fusion of that suture in rabbits. Furthermore, it appears that the mere application of methyl-2-cyanoacrylate to the periosteum overlying a suture will consistently cause the formation of a bony bridge in growing rabbits but not in nongrowing animals. The adhesive does not consistently induce synostosis if the periosteum is excised.

Malignant transformation of a dysembryoplastic neuroepithelial tumor

2000 ◽  
Vol 92 (4) ◽  
pp. 722-725 ◽  
Author(s):  
Robert R. Hammond ◽  
Neil Duggal ◽  
John M. J. Woulfe ◽  
John P. Girvin
Keyword(s):  
Malignant Transformation ◽  
Complex Form ◽  
Ct Scanning ◽  
Subtotal Resection ◽  
Dysembryoplastic Neuroepithelial Tumor ◽  
Content Type ◽  
Recent Onset ◽  
Fibrillary Astrocytoma ◽  
Fine Print ◽  
Glial Nodules

✓ A 29-year-old man presented in 1984 with a recent onset of partial seizures marked by speech arrest. Electroencephalography identified a left frontotemporal dysrhythmia. Computerized tomography (CT) scanning revealed a superficial hypodense nonenhancing lesion in the midleft frontal convexity, with some remodeling of the overlying skull. The patient was transferred to the London Health Sciences Centre for subtotal resection of what was diagnosed as a “fibrillary astrocytoma (microcystic).” He received no chemotherapy or radiation therapy and remained well for 11 years.The patient presented again in late 1995 with progressive seizure activity. Both CT and magnetic resonance imaging demonstrated a recurrent enhancing partly cystic lesion. A Grade IV astrocytoma was resected, and within the malignant tumor was a superficial area reminiscent of a dysembryoplastic neuroepithelial tumor (DNT). Data on the lesion that had been resected in 1984 were reviewed, and in retrospect the lesion was identified as a DNT of the complex form. It was bordered by cortical dysplasia and contained glial nodules, in addition to the specific glioneuronal element. The glial nodules were significant for moderate pleomorphism and rare mitotic figures. The Ki67 labeling index averaged 0.3% in the glial nodules and up to 4% focally. Cells were rarely Ki67 positive within the glioneuronal component. This case is the first documented example of malignant transformation of a DNT. It serves as a warning of the potential for malignant transformation in this entity, which has been traditionally accepted as benign. This warning may be especially warranted when confronted with complex forms of DNT. The completeness of resection in the benign state is of paramount importance.

Thymidine kinase-mediated killing of rat brain tumors

1993 ◽  
Vol 79 (5) ◽  
pp. 729-735 ◽  
Author(s):  
David Barba ◽  
Joseph Hardin ◽  
Jasodhara Ray ◽  
Fred H. Gage
Keyword(s):  
Gene Therapy ◽  
Brain Tumors ◽  
Tumor Cells ◽  
Wild Type ◽  
Cns Disorders ◽  
Content Type ◽  
Potential Applications ◽  
Ganciclovir Treatment ◽  
The Brain ◽  
Fine Print

✓ Gene therapy has many potential applications in central nervous system (CNS) disorders, including the selective killing of tumor cells in the brain. A rat brain tumor model was used to test the herpes simplex virus (HSV)-thymidine kinase (TK) gene for its ability to selectively kill C6 and 9L tumor cells in the brain following systemic administration of the nucleoside analog ganciclovir. The HSV-TK gene was introduced in vitro into tumor cells (C6-TK and 9L-TK), then these modified tumor cells were evaluated for their sensitivity to cell killing by ganciclovir. In a dose-response assay, both C6-TK and 9L-TK cells were 100 times more sensitive to killing by ganciclovir (median lethal dose: C6-TK, 0.1 µg ganciclovir/ml; C6, 5.0 µg ganciclovir/ml) than unmodified wild-type tumor cells or cultured fibroblasts. In vivo studies confirmed the ability of intraperitoneal ganciclovir administration to kill established brain tumors in rats as quantified by both stereological assessment of brain tumor volumes and studies of animal survival over 90 days. Rats with brain tumors established by intracerebral injection of wild-type or HSV-TK modified tumor cells or by a combination of wild-type and HSV-TK-modified cells were studied with and without ganciclovir treatments. Stereological methods determined that ganciclovir treatment eliminated tumors composed of HSV-TK-modified cells while control tumors grew as expected (p < 0.001). In survival studies, all 10 rats with 9L-TK tumors treated with ganciclovir survived 90 days while all untreated rats died within 25 days. Curiously, tumors composed of combinations of 9L and 9L-TK cells could be eliminated by ganciclovir treatments even when only one-half of the tumor cells carried the HSV-TK gene. While not completely understood, this additional tumor cell killing appears to be both tumor selective and local in nature. It is concluded that HSV-TK gene therapy with ganciclovir treatment does selectively kill tumor cells in the brain and has many potential applications in CNS disorders, including the treatment of cancer.

Progressive neurological deficits with benign intracerebral cysts

1986 ◽  
Vol 65 (5) ◽  
pp. 706-709 ◽  
Author(s):  
Yoko Nakasu ◽  
Jyoji Handa ◽  
Kazuyoshi Watanabe
Keyword(s):  
Histological Examination ◽  
Computerized Tomography ◽  
Cyst Wall ◽  
Benign Lesion ◽  
Ct Scanning ◽  
Neurological Deficits ◽  
Review Of The Literature ◽  
Content Type ◽  
Ct Findings ◽  
Fine Print

✓ Two patients with benign intracerebral cysts are reported and a brief review of the literature is given. Although computerized tomography (CT) scanning is useful in detecting a variety of intracerebral cysts, the CT findings are not specific for any lesion. An exploratory operation with establishment of an adequate route of drainage and a histological examination of the cyst wall are mandatory in the management of patients with a progressive but benign lesion.

The use of computerized tomography in the diagnosis of cerebral hydatid cysts

1979 ◽  
Vol 50 (3) ◽  
pp. 339-342 ◽  
Author(s):  
Tuncalp Özgen ◽  
Aykut Erbengi ◽  
Vural Bertan ◽  
Süleyman Saǧlam ◽  
Özdemir Gürçay ◽  
...  
Keyword(s):  
Hydatid Cyst ◽  
Computerized Tomography ◽  
Ct Scanning ◽  
Hydatid Cysts ◽  
Content Type ◽  
Cerebral Hydatid Cyst ◽  
Cyst Membrane ◽  
Fine Print

✓ Eleven cases of cerebral hydatid cyst, diagnosed by computerized tomography (CT), are presented. The importance of CT in minimizing the possibility of accidentally tapping or tearing the cyst membrane is stressed. Repeat CT scanning after removal of the cyst revealed atrophy in the affected hemisphere.

The effects of dexamethasone on bone fusion in an experimental model of posterolateral lumbar spinal arthrodesis

2001 ◽  
Vol 94 (1) ◽  
pp. 76-81 ◽  
Author(s):  
Paul D. Sawin ◽  
Curtis A. Dickman ◽  
Neil R. Crawford ◽  
M. Stephen Melton ◽  
William D. Bichard ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Bone Graft ◽  
Spinal Fusion ◽  
Experimental Model ◽  
Content Type ◽  
Bone Fusion ◽  
Group 12 ◽  
Spinal Arthrodesis ◽  
Lumbar Spinal ◽  
Fine Print

Object. The use of corticosteroid agents during the healing phase after spinal arthrodesis remains controversial. Although anecdotal opinion suggests that corticosteroids may inhibit bone fusion, such an effect has not been substantiated in clinical trials or laboratory investigations. This study was undertaken to delineate the effect of exogenous corticosteroid administration on bone graft incorporation in an experimental model of posterolateral lumbar fusion. Methods. An established, well-validated model of lumbar intertransverse process spinal fusion in the rabbit was used. Twenty-four adult New Zealand white rabbits underwent L5–6 bilateral posterolateral spinal fusion in which autogenous iliac crest bone graft was used. After surgery, the animals were randomized into two treatment groups: a control group (12 rabbits) that received intramuscular injections of normal saline twice daily and a dexamethasone group (12 rabbits) that received intramuscular dexamethasone (0.05 mg/kg) twice daily. After 42 days, the animals were killed and the integrity of the spinal fusions was assessed by radiography, manual palpation, and biomechanical testing. In seven (58%) of the 12 control rabbits, solid posterolateral fusion was achieved. In no dexamethasone-treated rabbits was successful fusion achieved (p = 0.003). Tensile strength and stiffness of excised spinal segments were significantly lower in dexamethasone-treated animals than in control animals (tensile strength 91.4 ± 30.6 N and 145.3 ± 48.2, respectively, p = 0.004; stiffness 31.4 ± 11.6 and 45.0 ± 15.2 N/mm, respectively, p = 0.02). Conclusions. The corticosteroid agent dexamethasone inhibited bone graft incorporation in a rabbit model of single-level posterolateral lumbar spinal fusion, inducing a significantly higher rate of nonunion, compared with that in saline-treated control animals.

Sign in / Sign up

Export Citation Format

Share Document