Sei Shibuya

Temporal progressive antigen expression in radial glia after contusive spinal cord injury in adult rats.

In the development of the CNS, radial glial cells are among the first cells derived from neuroepithelial cells. Recent studies have reported that radial glia possess properties of neural stem cells. We analyzed the antigen expression and distribution of radial glia after spinal cord injury (SCI). Sprague‐Dawley rats had a laminectomy at Th11‐12, and spinal cord contusion was created by compression with 30g of force for 10 min. In the injury group, rats were examined at 24 h and 1, 4, and 12 weeks after injury. Frozen sections of 20‐μm thickness were prepared from regions 5 and 10 mm rostral and caudal to the injury epicenter. Immunohistochemical staining was performed using antibodies to 3CB2 (a specific marker for radial glia), nestin, and glial fibrillary acidic protein (GFAP). At 1 week after injury, radial glia that bound anti‐3CB2 MAb had spread throughout the white matter from below the pial surface. From 4 weeks after injury, 3CB2 expression was also observed in the gray matter around the central canal, and was especially strong around the ependymal cells and around blood vessels. In double‐immunohistochemical assays for 3CB2 and GFAP or 3CB2 and nestin, coexpression was observed in subpial structures that extended into the white matter as arborizing processes and around blood vessels in the gray matter. The present study demonstrated the emergence of radial glia after SCI in adult mammals. Radial glia derived from subpial astrocytes most likely play an important role in neural repair and regeneration after SCI. GLIA 42:172–183, 2003.

Post-traumatic moderate systemic hypothermia reduces TUNEL positive cells following spinal cord injury in rat

Study design: A standardized animal model of contusive spinal cord injury (SCI) with incomplete paraplegia was used to test the hypothesis that moderate systemic hypothermia reduces neural cell death. Terminal deoxynucleotidyl transferase [TdT]-mediated deoxyuridine triphosphate [dUTP] nick-end labeling (TUNEL) staining was used as a marker of apoptosis or cell damage.Objective: To determine whether or not moderate hypothermia could have a neuroprotective effect in neural cell death following spinal cord injury in rats.Setting: Kagawa Medical University, Japan.Methods: Male Sprague–Dawley (SD) rats (n=39) weighing on average 300 g (280–320 g) were used to prepare SCI models. After receiving contusive injury at T11/12, rats were killed at 24 h, 72 h, or 7 days after injury. The spinal cord was removed en bloc and of examined at five segments: 5 and 10 mm rostral to the center of injury, center of injury, and 5 and 10 mm caudal to the center of injury. Rats that received hypothermia (32°C/4 h) were killed at the same time points as those that received normothermia (37°C/3 h). The specimens were stained with hematoxylin and eosin, and subjected to in situ nick-end labeling (TUNEL), a specific method for visualizing cell death in the spinal cord.Results: At 24 h postinjury, TUNEL positive cells (TPC) decreased significantly 10 mm rostral to center of injury in hypothermic animals compared to the normothermia group. At 72 h post-SCI, TPC also decreased significantly at 5 mm rostral, and 5 and 10 mm caudal to the lesion center compared to normothermic animals. At 7 days postinjury, a significant decrease of TPC was observed at the 5 mm rostral and 5 mm caudal sites compared to normothermic animals.Conclusion: These results indicate that systemic hypothermia has a neuroprotective effect following SCI by attenuating post-traumatic TPC.

Differences between subtotal corpectomy and laminoplasty for cervical spondylotic myelopathy.

Objective:This study aimed to obtain guidelines for choosing between subtotal corpectomy (SC) and laminoplasty (LP) by analysing the surgical outcomes, radiological changes and problems associated with each surgical modality.Study Design:A retrospective analysis of two interventional case series.Setting:Department of Orthopaedic Surgery, Kagawa University, Japan.Methods:Subjects comprised 34 patients who underwent SC and 49 patients who underwent LP. SC was performed by high-speed drilling to remove vertebral bodies. Autologous strut bone grafting was used. LP was performed as an expansive open-door LP. The level of decompression was from C3 to C7. Clinical evaluations included recovery rate (RR), frequency of C5 root palsy after surgery, re-operation and axial pain. Radiographic assessments included sagittal cervical alignment and bone union.Results:Comparisons between the two groups showed no significant differences in age at surgery, preoperative factors, RR and frequency of C5 palsy. Progression of kyphotic changes, operation time and volumes of blood loss and blood transfusion were significantly greater in the SC (two- or three-level) group. Six patients in the SC group required additional surgery because of pseudoarthrosis, and four patients underwent re-operation because of adjacent level disc degeneration. In the LP group, the problem of elimination of postoperative axial symptoms remains to be solved.Conclusions:The merit of SC is the low frequency of axial symptoms. One-level SC can be considered to have similar degree of invasiveness as LP. Compared with SC, LP is more suitable for elderly patients with multilevel stenosis.

Glial and axonal regeneration following spinal cord injury

Spinal cord injury (SCI) has been regarded clinically as an irreversible damage caused by tissue contusion due to a blunt external force. Past research had focused on the analysis of the pathogenesis of secondary injury that extends from the injury epicenter to the periphery, as well as tissue damage and neural cell death associated with secondary injury. Recent studies, however, have proven that neural stem (progenitor) cells are also present in the brain and spinal cord of adult mammals including humans. Analyses using spinal cord injury models have also demonstrated active dynamics of cells expressing several stem cell markers, and methods aiming at functional reconstruction by promoting the potential self-regeneration capacity of the spinal cord are being explored. Furthermore, reconstruction of the neural circuit requires not only replenishment or regeneration of neural cells but also regeneration of axons. Analysis of the tissue microenvironment after spinal cord injury and research aiming to remove axonal regeneration inhibitors have also made progress. SCI is one of the simplest central nervous injuries, but its pathogenesis is associated with diverse factors, and further studies are required to elucidate these complex interactions in order to achieve spinal cord regeneration and functional reconstruction.

Co-expression of radial glial marker in macrophages/microglia in rat spinal cord contusion injury model.

Macrophages/microglia are implicated in spinal cord injury but their precise role in the process is not clear. Our previous studies have reported that radial glia (RG) possess properties of neural stem cells and remerged after central nervous system (CNS) injury which may play an important role in neural repair and regeneration. In the present study, we examined the expression of ED1 (a specific marker for activated macrophages/microglia) and RG in a spinal cord injury (SCI) model and detected the activation at 1, 4, 8, and 12 weeks in both dorsal funiculus and ventral white matter after SCI. For both ED1-positive cells and RG cells, there was a gradual increase in density and in number from 1 to 4 weeks followed by down-regulation up to 12 weeks after injury. The morphologies of macrophages and radial glia were different. However, some ED1-positive cells were also stained by RG marker. These results suggest that macrophages may have some lineage to radial glial cells.

Clinical outcomes of percutaneous curettage and continuous irrigation for pyogenic spondylitis.

BACKGROUND Several recent studies have reported percutaneous curettage and continuous irrigation as effective treatments for pyogenic spondylitis. However, factors affecting the normalization of CRP levels remain unclear. This retrospective study investigated the clinical outcomes of percutaneous curettage and continuous irrigation for pyogenic spondylitis, and factors affecting the duration until normalization of CRP levels. METHODS Subjects comprised 16 patients who underwent percutaneous curettage and continuous irrigation for pyogenic spondylitis. Patients were divided into 3 groups according to duration from surgery until normalization of CRP levels to <or=0.20 mg/dL: early (n = 5), <or=2 weeks; middle (n = 6), <or=6 weeks; and delayed (n = 5), >6 weeks. Clinical and radiographic findings were compared between groups. RESULTS Japanese Orthopaedic Association score was improved in all patients within 2 weeks after surgery. Preoperative CRP level was lower in the early group (0.55 +/- 0.27 mg/dL) compared with the middle (2.63 +/- 1.84 mg/dL; P < .05) and delayed groups (7.59 +/- 10.44; P < .05). Duration of irrigation was shorter in the delayed group (10.7 +/- 3.7 days) compared with the early (15.6 +/- 2.0 days; P < .05) and middle groups (15.5 +/- 3.0 days; P < .05). Findings on MRI improved within 2 months in the early and middle groups. CONCLUSIONS This treatment is minimally invasive and useful in patients with pyogenic spondylitis. Lower CRP level before surgery and longer duration of irrigation may reduce the duration to normalization of CRP level.

Percutaneous curettage and continuous irrigation for MRSA lumbar spondylodiscitis: a report of three cases.

There has been a recent increase in pyogenic spondylitis caused by methicillin-resistant Staphylococcus aureus (MRSA) associated with an increasing number of compromised patients. As long as serious paralysis is absent, we recommend percutaneous curettage and continuous irrigation as an effective treatment for MRSA lumbar spondylodiscitis. Under local anesthesia, the affected lumbar discs were curetted using percutaneous nucleotomy, and tubes were placed for continuous irrigation. The period of continuous irrigation was generally 2 weeks. Infection was controlled after one procedure in two cases and after two procedures in one case. Postoperative radiography and magnetic resonance imaging (MRI) showed callus formation, normalized signal intensity in vertebral bodies, and regression of abscesses. Open surgery under general anesthesia has been considered risky in patients with poor performance status or old age. The present method, which is an application of needle biopsy, can be performed under local anesthesia and is minimally invasive.

Percutaneous Discectomy—Continuous Irrigation and Drainage for Tuberculous Lumbar Spondylitis: A Report of Two Cases

Percutaneous curettage and continuous irrigation were performed for definitive diagnosis and treatment of tuberculous (TB) lumbar spondylitis. Under local anaesthesia, affected lumbar discs were curetted using a procedure of percutaneous nucleotomy, and in-tube and the out-tube were placed for continuous irrigation. The period of continuous irrigation was 12–16 days. Mycobacterium tuberculosis was demonstrated in case 1 by culture and PCR, whereas histology showed tuberculous lesion with caseous necrosis in both cases. Postoperative MRI showed markedly reduced abscesses after 3 months in both cases. The signal intensity in vertebral bodies was improved. In Case 2, CT observations showed remodeling over time in the vertebral body cavities. This method is advantageous in that although minimally invasive, it achieves identification of pathogenic bacteria and treatment simultaneously. This surgical procedure is expected to prove effective for both TB and pyogenic spondylitis.