Takatoshi Shimomura

Sustained transgene expression in intervertebral disc cells in vivo mediated by microbubble-enhanced ultrasound gene therapy.

Study Design. In vivo studies using a rat model were performed to determine the feasibility of microbubble-enhanced ultrasound gene transfer technique to the intervertebral disc. Objectives. 1) To establish this microbubble-enhanced ultrasound gene therapy technique for intervertebral disc cells in vivo without using viral vectors and 2) to estimate the duration of transgene expression in vivo. Summary of Background Data. Intervertebral disc degeneration and associated spinal disorders remain a formidable problem. Although gene therapy approaches have been reported as having promising therapeutic potential to regenerate the disc, concerns over safety issues using recombinant viral vectors limits its application. Successful gene transfer using ultrasound has been reported in muscle and cardiovascular systems in vivo. Materials and Methods. Two different reporter plasmid DNA encoding green fluorescent protein (GFP) and firefly luciferase were used. Plasmid DNA was mixed with ultrasonography contrast agent (microbubbles) and injected into coccygeal intervertebral discs of Sprague-Dawley rats. The therapeutic ultrasound was irradiated on the surface of injected discs. Rats were killed 1, 3, 6, 12, and 24 weeks after gene transduction. Harvested nucleus pulposus tissues were used for evaluation of transgene expression. The intact discs were used as a control. Results. Seven days after gene transfection, considerable numbers of GFP-positive cells were observed in nucleus pulposus from the GFP-transfected group. Luciferase assay revealed that the ultrasound group demonstrated approximately an 11-fold increase in luciferase activity over the plasmid DNA-only group. Furthermore, transgene expression mediated by this method was observed, at least up to 24 weeks. Conclusions. Our study indicated that ultrasound transfection method with microbubbles significantly enhanced transfection efficiency of plasmid DNA into the nucleus pulposus cells in vivo. Furthermore, the sustained transgene expression in vivo was possible up to 24 weeks. The long-term gene expression mediated by simple and safe procedure has important clinical applications, including the treatment of chronic types of disease such as degenerative disc diseases.

Prognostic factors for deterioration of patients with cervical spondylotic myelopathy after nonsurgical treatment.

Study Design. A prospective study involving 56 patients with cervical spondylotic myelopathy (CSM) was conducted. Objective. To investigate the outcomes and prognostic factors for CSM after nonsurgical treatment. Summary of Background Data. The superiority of surgical treatment over nonsurgical treatment has not been confirmed in mild forms of CSM. Outcomes and prognostic factors for nonsurgical treatment of mild forms of CSM are not well understood. Methods. Clinical signs and symptoms of CSM were assessed by Japanese Orthopedic Association (JOA) scores. Nonsurgical treatment was selected for patients with mild forms of CSM (JOA ≥13 patients). Seventy patients with mild forms of CSM were enrolled in the study between 1995 and 2003. The follow-up rate was 80.0%. Prognostic factors that exacerbate clinical symptoms of CSM were examined, such as age, gender, follow-up period, developmental or dynamic factors on plain lateral radiograph, high signal intensity area on T2-weighted sagittal MRI, and the extent of maximum cord compression; partial or circumferential spinal cord compression, on axial MRI. Univariate and multivariate logistic regression analysis were carried out to test for significant prognostic factors. Results. There was, on average, no statistically significant deterioration in JOA scores after nonsurgical treatment. However, 11 of 56 patients deteriorated after nonsurgical treatment. The only factor that significantly exacerbated clinical symptoms of CSM was circumferential spinal cord compression in the maximum compression segment on axial MRI. Indeed, 10 of 33 CSM patients with circumferential spinal cord compression on axial MRI deteriorated after nonsurgical treatment. Conclusion. Outcomes of mild forms of CSM during nonsurgical treatment were generally good as shown by average JOA scores. The only prognostic factor for mild forms of CSM was circumferential spinal cord compression in the maximum compression segment on axial MRI. Surgical treatment can be considered for patients with this prognostic factor.

Fas ligand expression on human nucleus pulposus cells decreases with disc degeneration processes

BackgroundThe intervertebral disc has been reported to be an immunologically privileged environment, possibly mediated by Fas ligand (FasL) expression. On the other hand, recent studies have shown the infiltration of host immune cells into the degenerated disc, which may indicate the failure of the immune-privilege feature of the disc with degeneration. However, the relationship between FasL expression and disc degeneration is still unclear. Therefore, the purpose of this study was to clarify the relationship between FasL expression and disc degeneration.MethodsTen human degenerated disc specimens were obtained from spondylolisthesis patients and ten nondegenerated discs from idiopathic scoliosis patients during surgical procedures. Immunohistochemical staining was performed to determine the presence of FasL in cross-sections of those discs. Parts of the disc tissues were used to examine FasL expression quantitatively with Western blot analysis. To examine whether the change in FasL expression was influenced by aging, an animal study comparing the discs from young and old rats were performed using magnetic resonance imaging (MRI) and real-time polymerase chain reaction (PCR) assessment.ResultsNucleus pulposus cells showed strong positive staining for FasL in all specimens examined. Quantitative examination demonstrated a significant decrease in FasL expression in the degenerated group compared with the nondegenerated group (average 67.6%, P<0.05). MRI showed no significant differences in the grade of disc degeneration between young and old rats, and also no significant difference in FasL mRNA in real-time PCR assay.ConclusionsThe current results indicate that FasL and its potential mechanism of immunological privilege could influence the protection of the intervertebral disc against degeneration.

The prognosis of conservative treatments for lumbar spinal stenosis: analysis of patients over 70 years of age.

Study Design. A prospective study. Objectives. To identify outcomes of aged patients with lumbar spinal stenosis (LSS) treated conservatively and to examine factors that control the prognosis. Summary and Background Data. There have been no reports evaluating the outcomes of conservative treatments for elderly LSS patients. Methods. A total of 89 patients, 70 years of age and older, who underwent in-hospital conservative treatment were included. The Japanese Orthopedic Association’s score (JOA score) and the disturbance level of activities of daily living (ADL) were used for evaluation. Nerve involvement was classified into radicular, cauda equina, and mixed type. Myelographic findings were classified into central defect with or without block and root defect. Associations between disturbance level of ADL, nerve involvement, and myelographic classifications were investigated. Results. The mean JOA score increased from 11.1 points at admission to 15.9 points at discharge, with 14.3 points maintained at the follow-up; 48.8% of radicular type showed no obstacle in ADL at the follow-up compared with 33.3% of the other types; 13.3% of central defect with block showed no obstacle in ADL compared with 47.8% of the other types with significant difference. Conclusion. The prognosis of conservative treatment for aged LSS was relatively good. Radicular type may be a candidate for conservative treatment. However, patients with complete block in the myelogram may not respond favorably to conservative treatment.

Calcium pyrophosphate dihydrate deposition in the transverse ligament of the atlas: an unusual cause of cervical myelopathy

A 75-year-old male presented with progressive myelopathy due to massive retro-odontoid deposits of calcium pyrophosphate dehydrate (CPPD) crystals. Magnetic resonance imaging revealed a non-enhanced isointense extradural mass on a T1-weighted image and a heterogeneous intense mass on a T2-weighted image. Computed tomography (CT) showed linear calcification within the mass. The mass was resected via a posterolateral approach resulting in marked improvement of the symptoms. Histological examination revealed birefringent rhomboid crystals consistent with CPPD. The preoperative differential diagnosis of periodontoid CPPD deposition disease in the elderly population should be considered, particularly if CT studies demonstrate small areas of calcification within the retro-odontoid mass.

Thoracic myelopathy due to ossification of the yellow ligament in young baseball pitchers.

Study Design Case series. Objectives To report rare cases of thoracic myelopathy due to ossification of the yellow ligament (OYL) in relatively young baseball pitchers and show clinical evidence of the role of dynamic mechanical stress on the development of OYL. Summary of Background Data The pathogenesis of OYL is still unclear. The majority of cases of OYL occur in middle-aged men whereas younger people are rarely affected. This has lead to the hypothesis that diffuse mechanical stress and degenerative changes correlate with the development of OYL. However, there have been no clinical reports demonstrating the critical role of mechanical stress in the ossification. Methods Two young highly active baseball pitchers with thoracic myelopathy due to OYL are presented. Both had no previous systemic disorders or family history of treatment for OYL. Magnetic resonance imaging and computed tomography demonstrated compression of the spinal cord by unilateral left sided OYL at the level of the thoracolumbar junction. Results Both patients were treated with posterior decompression. They recovered full muscle power after operation and resumed pitching training. Conclusions Patients had no other factors influencing the development of OYL and the lesions were localized at the left side in the thoracolumbar junction, indicating that repeated, localized rotatory mechanical stress caused by the pitching motion probably influenced the development of OYL in these young baseball pitchers.

Two-stage decompression, reduction, and interbody fusion for lumbosacral spondyloptosis through a posterior approach using Ilizarov external fixation.

The suggested methods of treatment for spondyloptosis have included benign neglect, in situ fusion and variations, decompression and fusion, and vertebrectomy (the Gaines procedure). On review of the literature, the authors found no previous report in the English-language literature in which external fixation was used in the treatment of spondyloptosis. This 33-year-old woman with spondyloptosis underwent a 2-stage operation involving decompression, reduction, and posterior fusion in which an Ilizarov external fixator and transpedicular fixation system were used. Spondylolisthesis with a slippage of angle 78 degrees and > 100% slippage was partially reduced to 30 degrees and 60% without neurological alterations and without complications. The postoperative follow-up showed marked improvement in her symptoms and a good cosmetic result. Reconstructed computed tomography scanning at 18 months demonstrated complete fusion. The use of external fixation in the treatment of spondyloptosis may be preferable because of its neurological safety, despite the longer duration of treatment, than single-stage operation. The authors believe posterior decompression of the cauda equina, partial reduction of the spondylolisthetic deformity, interbody fusion, and stabilization with an external fixator and transpedicular fixation system can be successfully and safely used as a 2-stage treatment for adult high-grade spondyloptosis.

Posterior vertebral shortening with screw and hook placement for osteoporotic vertebral collapse with paraplegia.

Posterior vertebral shortening with pedicle screw and hook placement is a feasible treatment for delayed vertebral collapse with neurological deficits after osteoporotic spinal fracture.