Usefulness of anterior cervical fusion using titanium interbody cage for treatment of cervical degenerative disease with preoperative segmental kyphosis

Favorable bone fusion and clinical results have been reported for anterior cervical fusion (ACF) using titanium interbody cage (TIC). This method might induce postoperative subsidence and local kyphosis, but the relationship between radiological changes and preoperative local alignment is not known. The purpose of the present study is to investigate the impact of preoperative local alignment on the clinical and radiological outcomes of ACF using TIC.The study enrolled 36 patients (mean age 49.8 years) who underwent single-level ACF using TIC for cervical degenerative diseases. Patients were divided into 2 groups by preoperative segmental lordotic angle at the operative level: group L, ≥0° (n = 16); group K, <0° (n = 20). Clinical outcomes included recovery rate according to the Japanese Orthopaedic Association score and complication rates. Radiological assessment was conducted for the cervical and segmental lordotic angles, subsidence, and bone fusion. Mann-Whitney test and chi-square test were applied to compare the outcomes.The Japanese Orthopaedic Association score recovery rate was 77.2% in group L and 87.6% in group K, with no significant difference. No obvious complications were observed in any of the subjects. Mean cervical lordotic angles preoperatively and at last follow-up were 9.2 ± 9.5° and 11.3 ± 11.7°, respectively, in group L, and -1.3 ± 12.8° and 4.6 ± 13.3°, respectively, in group K. The mean segmental lordotic angles preoperatively and at last follow-up were 2.5 ± 2.2° and 2.6 ± 5.7°, respectively, in group L, and -4.5 ± 2.8° and -1.4 ± 5.8°, respectively, in group K. In group K, the cervical and segmental lordotic angles at the last follow-up were significantly greater than the preoperative angles. The change observed in group L was not significant. Subsidence of ≥3 mm was observed in 3 patients in group L and 4 patients in group K. None of the patients showed nonunion.Anterior cervical fusion using TIC provided favorable clinical results regardless of preoperative segmental alignment. Although postoperative subsidence and kyphotic changes are concerns in patients presenting segmental kyphosis, ACF using TIC corrected both the entire cervical spine and segmental alignment. The TIC is useful for correction of the cervical alignment for patients with cervical degenerative disease with local kyphotic changes.

Prevention of neurological complications using a neural monitoring system with a finger electrode in the extreme lateral interbody fusion approach

OBJECTIVE

Extreme lateral interbody fusion (XLIF) is a minimally disruptive surgical procedure that uses a lateral approach. There is, however, concern about the development of neurological complications when this approach is used, particularly at the L4–5 level. The authors performed a prospective study of the effects of a new neural monitoring system using a finger electrode to prevent neurological complications in patients treated with XLIF and compared the results to results obtained in historical controls.

METHODS

The study group comprised 36 patients (12 male and 24 female) who underwent XLIF for lumbar spine degenerative spondylolisthesis or lumbar spine degenerative scoliosis at L4–5 or a lower level. Using preoperative axial MR images obtained at the mid-height of the disc at the treated level, we calculated the psoas position value (PP%) by dividing the distance from the posterior border of the vertebral disc to the posterior border of the psoas major muscle by the anteroposterior diameter of the vertebral disc. During the operation, the psoas major muscle was dissected using an index finger fitted with a finger electrode, and threshold values of the dilator were recorded before and after dissection. Eighteen cases in which patients had undergone the same procedure for the same indications but without use of the finger electrode served as historical controls. Baseline clinical and demographic characteristics, PP values, clinical results, and neurological complications were compared between the 2 groups.

RESULTS

The mean PP% values in the control and finger electrode groups were 17.5% and 20.1%, respectively (no significant difference). However, 6 patients in the finger electrode group had a rising psoas sign with PP% values of 50% or higher. The mean threshold value before dissection in the finger electrode group was 13.1 ± 5.9 mA, and this was significantly increased to 19.0 ± 1.5 mA after dissection (p < 0.001). A strong negative correlation was found between PP% and threshold values before dissection, but there was no correlation with threshold values after dissection. The thresholds after dissection improved to 11 mA or higher in all patients. There were no serious neurological complications in any patient, but there was a significantly lower incidence of transient neurological symptoms in the finger electrode group (7 [38%] of 18 cases vs 5 [14%] of 36 cases, p = 0.047).

CONCLUSIONS

The new neural monitoring system using a finger electrode may be useful to prevent XLIF-induced neurological complications.

Dislodgement and gastrointestinal tract penetration of bone cement used for spinal reconstruction after lumbosacral vertebral tumor excision: A case report

INTRODUCTION

Polymethylmethacrylate (PMMA) cement is useful for spinal reconstruction, but can cause complications including new vertebral fractures, neurological disorders and pulmonary embolism. We report a case in PMMA cement used for spinal reconstruction after tumor curettage dislodged and penetrated the gastrointestinal tract.

DIAGNOSES

The patient was diagnosed with a retroperitoneal extragonadal germ cell tumor at age 27 years. After chemotherapy and tumor resection, the tumor remained. It gradually increased in size and infiltrated lumbosacral vertebrae, causing him to present at age 35 years with increased low back pain. Image findings showed bone destruction in the vertebral bodies accompanied by neoplastic lesions. The left and right common iliac arteries and inferior vena cava were enclosed in the tumor on the anterior side of the vertebral bodies. Lumbosacral bone tumor due to direct extragonadal germ cell tumor infiltration was diagnosed. A 2-step operation was planned; first, fixation of the posterior side of the vertebral bodies, followed by tumor resection using an anterior transperitoneal approach, and spinal reconstruction using PMMA cement. After surgery, the PMMA cement gradually dislodged towards the anterior side and, 2 years 9 months after surgery, it had penetrated the retroperitoneum. The patient subsequently developed nausea and abdominal pain and was readmitted to hospital. The diagnosis was intestinal blockage with dislodged PMMA cement, and an operation was performed to remove the cement present in the small intestine. There was strong intra-abdominal adhesion, the peritoneum between the vertebral bodies and intestine could not be identified, and no additional treatment for vertebral body defects could be performed. After surgery, gastrointestinal symptoms resolved.

CONCLUSION

Although this was a rare case, when using bone cement for vertebral body reconstruction, the way of anchoring for the cement must be thoroughly planned to assure no cement dislodgement can occur.

Hepatocyte growth factor/c-met promotes proliferation, suppresses apoptosis, and improves matrix metabolism in rabbit nucleus pulposus cells in vitro

The etiology of intervertebral disc (IVD) degeneration is closely related to apoptosis and extracellular matrix degradation in nucleus pulposus (NP) cells. These defects in NP cells are induced by excessive external stressors such as reactive oxygen species (ROS) and inflammatory cytokines. Recently, hepatocyte growth factor (HGF) has been shown to repair damage in various diseases through anti-apoptotic and anti-inflammatory activity. In this study, we investigated the effects of HGF on NP cell abnormality caused by ROS and inflammatory cytokines by using primary NP cells isolated from rabbit IVD. HGF significantly enhanced the proliferation of NP cells. Apoptosis of NP cells induced by H2 O2 or TNF-α was significantly inhibited by HGF. Induction of mRNA expression of the inflammation mediators cyclooxygenase-2 and matrix metalloproteinase-3 and -9 by TNF-α was significantly suppressed by HGF treatment. Expression of c-Met, a specific receptor for HGF, was confirmed in NP cells and was increased by TNF-α, suggesting that inflammatory cytokines increase sensitivity to HGF. These findings demonstrate that activation of HGF/c-Met signaling suppresses damage caused by ROS and inflammation in NP cells through multiple pathways. We further suggest the clinical potential of HGF for counteracting IVD degradation involved in NP cell abnormalities.

Outcomes in cases of lumbar degenerative spondylolisthesis more than 5 years after treatment with minimally invasive decompression: examination of pre- and postoperative slippage, intervertebral disc changes, and clinical results

OBJECT

There are reports that fusion is the standard treatment of choice for cases of lumbar degenerative spondylolisthesis (LDS) associated with lumbar spinal canal stenosis with a large degree of slippage. The reasons why, however, have not been clarified. On the other hand, it is known that the progress of slippage decreases and restabilization occurs over the natural course of LDS. Therefore, if minimally invasive decompression could be performed, there would be little possibility of it influencing the natural course of LDS, so it would not be necessary to include preoperative percentage slip in the criteria for the selection of fusion. This study examined the course of LDS cases more than 5 years after treatment with minimally invasive decompression to determine whether pre- and postoperative slippage and disc changes influence the clinical results.

METHODS

A total of 51 intervertebral segments in 51 cases with the chief complaint of radicular or cauda equina symptoms due to lumbar spinal canal stenosis were examined after prospective treatment with minimally invasive decompression for LDS. The mean age of the patients at the time of surgery was 66.7 years and the mean follow-up period was 7 years 4 months. Minimally invasive decompression was performed regardless of the degree of low-back pain or percentage slip. The outcome variables were clinical results and changes in imaging findings.

RESULTS

Over the follow-up period, postoperative percentage slip increased and disc height decreased, but the Japanese Orthopaedic Association score improved. Regardless of the preoperative percentage slip, disc height, or degree of intervertebral disc degeneration or segmental instability, the clinical results were favorable. In the high preoperative percentage slip group, low disc height group, and progressive disc degeneration group, there was little postoperative progress of slippage. In the group with a postoperative slippage increase of more than 5%, slippage increased significantly at postoperative year 2, but no significant difference was observed at the final follow-up.

CONCLUSIONS

When minimally invasive decompression was performed to treat LDS, the postoperative change in slippage was no different from that during the natural course. Furthermore, regardless of the degree of preoperative slippage or intervertebral disc degeneration, the clinical results were favorable. Also, the higher the preoperative percentage slip and the more that disc degeneration progressed, the more the progress of postoperative slippage decreased. Because the postoperative progress of slippage decreased, it is believed that even after minimally invasive decompression, restabilization occurs as it would during the natural course. If minimally invasive decompression can be performed to treat LDS, it is believed that preoperative percentage slip and intervertebral disc degeneration do not have to be included in the appropriateness criteria for fusion.

Instrumented reduction and monosegmental fusion for Meyerding Grade IV developmental spondylolisthesis: a report of 3 cases

There are numerous reports of treatment methods for spondylolisthesis with a Meyerding Grade of more than III. In high dysplastic spondylosthesis, surgical treatment was selected because there is considered to be a high possibility of low back pain and lower limb neurological symptoms worsening if slippage progresses. Monosegmental lumbar interbody fusion (L5-S1) with a pedicle screw system (PPS) was used to treat three cases of Meyerding Grade IV developmental spondylolisthesis. Patients gave written informed consent. The spondylolisthesis was reduced to Meyerding Grade I and sagittal balance improved in all three cases. In two cases with severe spinal instability, there were no postoperative neurological complications and the course was favorable. However, in one case with little spinal mobility due to vertebral body dysplasia, despite performing sufficient decompression of the nerve root at L5 and slow reduction to avoid placing excessive tension on the nerve root, a transient neurological disorder was observed. A PPS was used to increase the reduction strength and favorable reduction was possible. However, in the case with a long clinical course and the case with poor spinal mobility, since the mobility and plasticity of the nerve root itself may have been reduced, it was considered that reduction should be performed carefully using intraoperative neurological monitoring.

Combined microwave irradiation and intraarticular glutamine administration-induced HSP70 expression therapy prevents cartilage degradation in a rat osteoarthritis model

The objective of the present study was to investigate the effects of heat stimulation and glutamine (Gln) on the expression of extracellular matrix genes and heat shock protein 70 (HSP70) in rat articular cartilage in vivo and to determine whether HSP70 expression achieved with a combination of microwave (MW) and Gln suppresses osteoarthritis (OA) progression in a rat OA model. Stimulation at 40 W was assumed to be appropriate in the present study, and the effects of heat treatment at this intensity were evaluated. Articular cartilage was collected at 8 h after heat stimulation and/or intraarticular Gln administration, and total RNA was extracted. The expression of HSP70, aggrecan, and type II collagen was quantified using real-time RT-PCR. Cartilage samples from the OA model were subjected to hematoxylin and eosin (HE) and safranin O staining. HSP70 and aggrecan expression was greatest in a group receiving both MW and Gln. In the rat OA model, the severity of OA was significantly milder in a group receiving MW and Gln than in the control group. HSP70, stimulated by the combination of MW heat and Gln, may be involved in the suppression of OA progression.

Influence of extracellular matrix on the expression of inflammatory cytokines, proteases, and apoptosis-related genes induced by hydrostatic pressure in three-dimensionally cultured chondrocytes

BACKGROUND

The purpose of this study was to investigate the influence of hydrostatic pressure (HP) on the gene expression of cartilage matrix, cytokines, and apoptosis-associated factors in chondrocytes in which the cartilage was in extracellular matrix (ECM)-rich or ECM-poor condition.

METHODS

Chondrocytes were isolated from rabbit joints and cultured in alginate beads. Immediately after embedding (0W group) or after 2 weeks culture (2W group), the amounts of glycosaminoglycan (GAG) in the alginate beads were quantified. Both groups were exposed to continuous HP of 10 or 50 MPa for 12 h. The expression of inflammatory cytokines, proteases, and apoptosis-related factors were examined by reverse transcription-polymerase chain reaction (RT-PCR). The expression of proteoglycan core protein (PG) and collagen type II were quantified by real-time RT-PCR.

RESULTS

All of the GAG components in alginate beads markedly increased in the 2W group. The expression of PG and collagen type II increased after exposure to 10 MPa in both groups. In the 0W group, these levels decreased after exposure to 50 MPa of HP. The expression of interleukins IL-6 and IL-8 increased after exposure to HP in the 0W group. HP at 50 MPa induced mRNA expression of ADAMTS-5 in the 0W group but not in the 2W group. The expression of Fas increased after exposure to HP in the 0W group.

CONCLUSIONS

These findings suggested that nonphysiological, excessive HP on chondrocytes with the ECM in poor condition reduced matrix gene expression and increased expression of the genes associated with apoptosis and catabolism of the cartilage matrix. These results might therefore be associated with the pathogenesis of osteoarthritis.

Intraarticular administration of platelet-rich plasma with biodegradable gelatin hydrogel microspheres prevents osteoarthritis progression in the rabbit knee

OBJECTIVE

To investigate the therapeutic potential of administration of gelatin hydrogel microspheres containing platelet-rich plasma (PRP), by examining its effects on progression of osteoarthritis (OA) in a rabbit model.

METHODS

PRP and platelet-poor plasma (PPP) were prepared from rabbit blood. Adult rabbit chondrocytes were cultured in the alginate beads with the presence of 3% PRP or 3% PPP. Glycosaminoglycan (GAG) synthesis was quantified using dimethylmethylene blue assay. To confirm the anabolic effect of PRP in vivo, cartilage matrix gene expression was examined after intraarticular administration of PRP contained in gelatin hydrogel microspheres. The PRP contained in gelatin hydrogel microspheres was administered into the rabbit knee joint twice with an interval of 3 weeks, beginning 4 weeks after anterior cruciate ligament transection (ACLT). Ten weeks after ACLT, gross morphological and histological examinations were performed.

RESULTS

PRP significantly stimulated chondrocyte GAG synthesis in vitro. In the knee joint, expression of proteoglycan core protein mRNA in the articular cartilage increased after administration of PRP contained in microspheres. Intraarticular injections of PRP in gelatin hydrogel microspheres significantly suppressed progression of OA in the ACLT rabbit model morphologically and histologically.

CONCLUSION

The present findings indicate that sustained release of growth factors contained in PRP has preventive effects against OA progression. These preventive effects appear to be due to stimulation of cartilage matrix metabolism, caused by the growth factors contained in PRP.

Induction of chondrogenic phenotype in synovium-derived progenitor cells by intermittent hydrostatic pressure

OBJECTIVE

The aim of this study was to investigate the effect of intermittent hydrostatic pressure (IHP) on chondrogenic differentiation of synovium-derived progenitor cells (SPCs).

METHODS

SPCs, bone marrow-derived progenitor cells and skin fibroblasts from rabbits were subjected to IHP ranging from 1.0 to 5.0 MPa. The mRNA expression of proteoglycan core protein (PG), collagen type II and SOX-9 was examined using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). The production of SOX-9 protein and glycosaminoglycan (GAG) by SPCs was analyzed by Western blot and the dimethylmethylene blue assay. In addition, mitogen-activated protein (MAP) kinase inhibitors for c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and the p38 pathway were used to identify the signal transduction pathways.

RESULTS

Real-time RT-PCR showed that mRNA expression of PG, collagen type II and SOX-9 was significantly enhanced only in SPCs receiving 5.0 MPa of IHP. The production of SOX-9 protein and GAG by SPCs was also increased by exposure to 5.0 MPa of IHP. These up-regulated expressions were suppressed by pretreatment with an inhibitor of JNK, but not with inhibitors of ERK or p38.

CONCLUSION

Our results demonstrated that the exposure of SPCs to 5.0 MPa of IHP could facilitate induction of the chondrogenic phenotype by the MAP kinase/JNK pathway. This finding suggests the potential for IHP utilization in regenerative treatments for cartilage injuries or osteoarthritis.

Enhanced expression of interleukin-6, matrix metalloproteinase-13, and receptor activator of NF-kappaB ligand in cells derived from osteoarthritic subchondral bone

BACKGROUND

The aim of this study was to clarify the significance of subchondral bone in the pathology of osteoarthritis (OA) by investigating the expression of inflammatory cytokines, proteases, and receptor activator of NF-kappaB ligand (RANKL)/receptor activator of NF-kappaB (RANK)/osteoprotegerin (OPG) involved in cartilage degeneration.

METHODS

Subchondral bone was obtained from 19 patients diagnosed with knee OA and 4 patients diagnosed with femoral neck fracture. Subchondral bone osteoblasts (SBOs) were isolated, and total RNA was extracted. Messenger RNA expression of inflammatory cytokines, proteases, and RANKL/RANK/OPG were analyzed using a real-time reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Real-time RT-PCR showed that mRNA expressions of interleukin-6 (IL-6), matrix metalloproteinase-13 (MMP-13), and RANKL were significantly enhanced in OA SBOs compared to SBOs without OA. The expressions of these genes was greater in patients with severe cartilage damage than in those with mild cartilage damage. A high correlation between mRNA expression of IL-6 and that of MMP-13 was found in OA SBOs.

CONCLUSION

The increases in IL-6, MMP-13, and RANKL expression in OA SBOs suggest that in subchondral bone OA progression involves abnormal osseous tissue remodeling, which induces mechanical property changes. Cartilage degeneration in OA may also be due, at least in part, to IL-6 and MMP-13 produced by SBOs. Comprehensive research on these pathological features may lead to the development of more effective therapies for OA by administration of molecules that affect bone remodeling and metabolism.

Effects of heat stimulation via microwave applicator on cartilage matrix gene and HSP70 expression in the rabbit knee joint

The objective of this study was to investigate the effects of heat stimulation on the expression of extracellular matrix genes and heat-shock protein 70 (HSP70) in rabbit articular cartilage in vivo. Heat stimulation was applied to the knee joints of Japanese white rabbits for 20 min using a microwave (MW) applicator (2.45-GHz, 0-80 W). After 8-72 h, the articular cartilage was removed from the knee joints and proteins and total RNA were extracted. As controls, knee joints without heat stimulation were analyzed. The expression of HSP70 was confirmed by real-time PCR and Western blotting. The expression of proteoglycan core protein (PG) and type II collagen (Col II) was quantified using real-time PCR to assess cartilage matrix metabolism. Compared to controls, HSP70 expression was higher with more than 40 W of heat stimulation. The expression of PG and Col II mRNA was higher, with more than 20 W of heat stimulation and peaked with 40 W. When quercetin was used to inhibit the induction of HSP70 expression, PG mRNA expression did not increase. External MW application stimulated HSP70 expression in the articular cartilage in vivo. The expression of extracellular matrix genes was increased by appropriate heat stimulation.

Spin disorder and order in quasi-2D triangular Heisenberg antiferromagnets: comparative study of FeGa2S4, Fe2Ga2S5, and NiGa2S4

Our single crystal study reveals that the single-layer S=2 triangular Heisenberg antiferromagnet FeGa2S4 forms a frozen spin-disordered state, similar to the S=1 isostructural magnet NiGa2S4. In this state, the magnetic specific heat C{M} is not only insensitive to the field, but shows a T2 dependence that scales to C{M} of NiGa2S4, suggesting the same underlying mechanism of the 2D coherent behavior. In contrast, the bilayer system Fe2Ga2S5 exhibits a 3D antiferromagnetic order.

Sonoporation mediated transduction of pDNA/siRNA into joint synovium in vivo

The purpose of this study was to investigate the usefulness of sonoporation method on in vivo transduction of plasmid DNA (pDNA) and small interfering RNA (siRNA) into joint tissue. pGEG.GL3 plasmid was mixed with microbubble and injected into knee joints of rats. Ultrasound sonication was performed percutaneously. Three days after injection, GL3 expression of synovial tissue was determined by luciferase assay and RT-PCR. siRNA specific for GL3 (siGL3) or nonspecific siRNA were mixed with pGEG.GL3 plasmid and transduced by sonoporation. siRNA specific for EGFP (siEGFP) was transduced into the knee joints of EGFP transgenic rats, and gene silencing effects for endogenous gene were examined. To determine the localization of transduced siRNA, fluorescently labeled siRNA was transduced into joints. The expression of GL3 in the synovium was significantly enhanced by sonoporation. The gene expression was only seen in the synovium of the knee joint. The expression of GL3 was remarkably suppressed by co-transduction of siGL3, but not suppressed by nonspecific siRNA. siEGFP transduced by sonoporation attenuated green fluorescence on the surface layer of synovium of EGFP transgenic rats. The fluorescently labeled siRNA was seen in the synovium around the patella, femur, and tibia. Sonoporation is examined as a recent, novel, gene transduction method, and the advantage of this technique is minimal invasiveness. In this study, we showed that pDNA/siRNA can be transduced specifically into the joint synovium using sonoporation. The present method may be useful in nucleic acid therapy for joint disorders.

Glutamine protects articular chondrocytes from heat stress and NO-induced apoptosis with HSP70 expression

OBJECTIVE

To investigate the effect of l-glutamine (Gln) on stress responses of chondrocytes exposed to heat stress or nitric oxide (NO).

METHODS

Cultures of articular chondrocytes were established from rabbit joints, and treated for 12h with various concentrations of Gln (0-20 mM). In some experiments, cells were also treated with quercetin (Que), a heat shock protein 70 (HSP70) inhibitor. Heat stress (43 degrees C) was applied to the cells for 0-120 min. Apoptosis was induced by 0.5mM sodium nitroprusside (SNP) dihydrate that produces NO. After stress loading, HSP70 expression was detected by Western blot analysis. Cell viability was assessed by lactate dehydrogenase (LDH) release and tetrazolium salt-based assays, while apoptosis was evaluated by Hoechst 33342 staining, TUNEL methods and active caspase-3 determination.

RESULTS

Gln demonstrated dose-dependent enhancing effect on stress-mediated induction of HSP70, while in the absence of any stress HSP70 was not induced by Gln alone. After heating or SNP loading, chondrocytes showed severe reduction in viability, while the cytotoxic outcome was almost completely abrogated by conditioning with Gln. The protective effect of Gln was significantly blocked by Que that effectively suppressed stress-induced HSP70 expression in chondrocytes. The Gln also rendered chondrocytes unsusceptible to NO-induced apoptosis that was frequently seen in SNP-treated culture.

CONCLUSION

This study demonstrated that the treatment of chondrocytes with Gln protected the cells from heat stress and NO-induced apoptosis. These chondroprotective effects of Gln may be mediated by HSP70.

Hydrostatic pressure induces apoptosis of chondrocytes cultured in alginate beads

The purpose of this study was to investigate the influence of hydrostatic pressure (HP) on apoptosis and expression of heat-shock protein 70 (HSP70) in chondrocytes cultured in alginate beads. Chondrocytes were isolated from the articular cartilage of rabbit joints and seeded in alginate beads. The beads in Group A were cultured for less than 24 h after being embedded with the chondrocytes, while those in Group B were cultured for 2 weeks. Both groups were exposed to HP of 10 or 50 MPa for 12 or 24 h. The beads in Groups A and B that were not exposed to HP were regarded as controls. Apoptotic cells induced by exposure to HP were quantified using the TUNEL method. Immunohistochemical analysis for HSP70 and in situ TUNEL analysis were also performed. Apoptotic chondrocytes were not observed in the control cells under atmospheric pressure, whereas apoptosis was observed in the beads in Group A, and the number of apoptotic cells increased as the duration and magnitude of HP increased. On the other hand, we observed no significant population of apoptotic cells in the beads in Group B. Chondrocytes expressing HSP70 were not TUNEL positive in the histological analysis. Excessively strong HP could evoke apoptosis when the extracellular matrix did not accumulate around the chondrocytes. HSP70 expression was related to occurrence of apoptosis that resulted from HP. These findings suggest a mechanism for the pathogenesis of cartilage degeneration in osteoarthritis.

The effect of apoptosis signal-regulating kinase 1 gene transfer on rat collagen induced arthritis

OBJECTIVE

To examine the apoptosis-inducing effect of apoptosis signal-regulating kinase 1 (ASK1) gene transfer into synovial cells in vitro and in vivo.

METHODS

An adenovirus vector was constructed so that a constitutively active form of ASK1 gene (ASK1DeltaN) was expressed in the presence of the Cre recombinase. The ASK1DeltaN and Cre adenovirus vectors were cotransduced into cultured synoviocytes derived from patients with rheumatoid arthritis (RA), and apoptosis was evaluated by TUNEL and Hoechst staining. Collagen induced arthritis (CIA) was induced in 8-week-old male DA rats, and 10 days later the 2 adenovirus vectors were coadministered into the ankle joints of the animals. As indicators of severity of arthritis, swelling of the ankle and articular index (AI) scores were evaluated, while histopathological observation of articular tissue was also performed.

RESULTS

In the cultured human RA synoviocytes, overexpression of the ASK1DeltaN significantly reduced cell viability and induced apoptosis. In the CIA rats transduced with the ASK1DeltaN gene, arthritis was significantly promoted in terms of the swelling of the ankle joints and elevation of the AI scores. Histopathological observation also revealed that the constitutively active ASK1 induced massive infiltration of inflammatory cells into the synovial membrane as well as proliferation of synovial fibroblasts. Degeneration of the synovial membrane was not evident.

CONCLUSION

Adenoviral transduction of ASK1DeltaN induced apoptosis in RA synoviocytes in vitro, but not in CIA synovium in vivo.

Electro-transfer of small interfering RNA ameliorated arthritis in rats

RNA interference provides the powerful means of sequence-specific gene silencing. Particularly, small interfering RNA (siRNA) duplexes may be potentially useful for therapeutic molecular targeting of human diseases, although novel delivery systems should be devised to achieve efficient and organ-specific transduction of siRNA. In the present study, we demonstrated that electro-transfer of a siRNA-polyamine complex made efficient and specific gene knockdown possible in the articular synovium. Targeted suppression of the tumor necrosis factor-alpha gene through this procedure significantly ameliorated collagen-induced arthritis in rats. Our results suggest the potential feasibility of therapeutic intervention with RNA medicines for treatment of rheumatoid and other locomotor diseases.

The therapeutic effects of basic fibroblast growth factor contained in gelatin hydrogel microspheres on experimental osteoarthritis in the rabbit knee

OBJECTIVE

To investigate the therapeutic effects of basic fibroblast growth factor (bFGF) contained in gelatin hydrogel microspheres on osteoarthritis (OA) development in rabbit knee joints.

METHODS

(125)I-labeled bFGF contained in gelatin hydrogel microspheres was administered to the knee joints of normal rabbits to confirm the sustained-release kinetics of bFGF in the knee joint. In addition, the expression of proteoglycan core protein messenger RNA was examined using real-time polymerase chain reaction to confirm the anabolic effects on the cartilage treated with the sustained release of bFGF. The bFGF in gelatin hydrogel microspheres was administered to the knee joint once every 3 weeks (a total of twice) from 4 weeks after anterior cruciate ligament transection (ACLT). Ten weeks after ACLT, gross morphologic and histologic examinations were performed.

RESULTS

Sustained release of bFGF in the knee joint continued for >7 days and induced the anabolic effects on the cartilage. Intraarticular injections of bFGF contained in gelatin hydrogel microspheres suppressed the progression of OA in the ACLT rabbit model.

CONCLUSION

Our findings demonstrated that sustained release of bFGF into the joint had therapeutic effects on OA development in a rabbit model. Our results suggest the potential feasibility of a new conservative treatment for OA.

Postnatal development of thiamine metabolism in rat skeletal muscle

1. The activities of 2-oxoglutarate dehydrogenase, transketolase, thiamine pyrophosphokinase and thiamine triphosphatase and the concentrations of thiamine phosphates were almost the same between rat extensor digitorum longus and soleus muscles at 2 weeks of age. 2. These enzyme activities changed after 3 weeks of age in a different way depending on the muscle phenotype. 3. Thiamine diphosphate level and the activity of 2-oxoglutarate dehydrogenase increased only in soleus muscle and thiamine triphosphate level increased only in extensor digitorum longus during development.

Membrane-associated thiamine triphosphatase in rat skeletal muscle

1. Thiamine triphosphatase activity in particulate fraction, but not in soluble, of rat skeletal muscle was stimulated by several anions. 2. The stimulative effect of anions was dependent on pH of reaction medium and was reversible. 3. The activities of ATPase in rat muscle particulate preparation and thiamine triphosphatase in the brain were inhibited by the anions.

Postnatal development of thiamine metabolism in rat brain

The activities of thiamine diphosphatase (TDPase), thiamine triphosphatase (TTPase), and thiamine pyrophosphokinase and the contents of thiamine and its phosphate esters were determined in rat brain cortex, cerebellum, and liver from birth to adulthood. Microsomal TTPase activity in the cerebral cortex and cerebellum increased from birth to 3 weeks, whereas that in the liver did not change during postnatal development. Microsomal TDPase activity in the cerebral cortex showed a transient increase at 1-2 weeks, but that in the cerebellum did not change during development. In contrast to the activity of the brain enzyme, that of liver microsomal TDPase increased stepwise after birth. Thiamine pyrophosphokinase activity in the cerebellum increased from birth to 3 weeks and then decreased, whereas that in the cerebral cortex and liver showed less change during development. TDP and thiamine monophosphate (TMP) levels increased after birth and plateaued at 3 weeks whereas TTP and thiamine levels showed little change during development in the cerebral cortex and cerebellum. The contents of thiamine and its phosphate esters in the liver showed more complicated changes during development. It is concluded that thiamine metabolism in the brain changes during postnatal development in a different way from that in the liver and that the development of thiamine metabolism differs among brain regions.

Difference in thiamine metabolism between extensor digitorum longus and soleus muscles

1. Thiamine diphosphate level was higher in soleus muscle than in extensor digitorum longus muscle in various animals, whereas thiamine triphosphate level was less in the former muscle than in the latter except for mouse. 2. 2-Oxoglutarate dehydrogenase, transketolase and thiamine pyrophosphokinase activities were higher in soleus muscle than in extensor digitorum longus in rat and guinea pig. 3. The differences between rat two muscle phenotypes in thiamine diphosphate, but not thiamine triphosphate, level and the thiamine-related enzyme activities disappeared after denervation. 4. Tenotomy had little effect on thiamine phosphate levels and the thiamine-related enzyme activities in rat skeletal muscles.