Induction of hypertrophic chondrocyte-like phenotypes by oxidized LDL in cultured bovine articular chondrocytes through increase in oxidative stress.

OBJECTIVE: It has been reported that the lectin-like oxidized low-density lipoprotein (Ox-LDL) receptor 1 (LOX-1) is expressed by chondrocytes in osteoarthritis (OA) cartilage and that Ox-LDL binding to LOX-1 increases intracellular oxidative stress in cultured bovine articular chondrocytes (BACs). It was recently demonstrated that reactive oxygen species (ROS) induce hypertrophic differentiation of chondrocytes in the growth plate. It has also been shown that activated chondrocytes in OA have hypertrophic chondrocyte-like phenotypes. The purpose of this study was to determine whether Ox-LDL induces hypertrophic chondrocyte-like phenotypes in BACs. DESIGN: Changes in type X collagen (COL10) and runt-related transcription factor 2 (Runx2) mRNA expression in BACs after Ox-LDL stimulation were investigated using real-time polymerase chain reaction (PCR). Western blotting and immunofluorescent cell staining were used to investigate changes in protein level. The antioxidant N-acetyl cysteine (NAC) was used to ascertain whether oxidative stress is involved in COL10 and Runx2 expression. We induced LOX-1 knockdown cells using small interfering RNA (siRNA) to examine the receptor specificity of Ox-LDL. RESULTS: COL10 expression was upregulated by Ox-LDL in a time- and dose-dependent manner. Immunofluorescent staining showed that Ox-LDL increased COL10 production in the extracellular matrix. Ox-LDL-induced upregulation of COL10 was suppressed by pretreatment with NAC and siRNA. Expression of Runx2 was upregulated by Ox-LDL and H(2)O(2), and these effects were suppressed by NAC pretreatment. CONCLUSION: Ox-LDL binding to LOX-1 induces a hypertrophic chondrocyte-like phenotype through oxidative stress, indicating that Ox-LDL plays a role in the degeneration of cartilage.

Oxidized LDL binding to LOX-1 enhances MCP-1 expression in cultured human articular chondrocytes.

OBJECTIVE: It has been suggested that oxidized low-density lipoprotein (ox-LDL) has some roles in progression of osteoarthritis. The purpose of this study is to investigate whether ox-LDL binding to lectin-like ox-LDL receptor 1 (LOX-1) enhances monocyte chemoattractant protein 1 (MCP-1) expression in cultured human articular chondrocytes (HACs). METHOD: The time course and dose response of MCP-1 mRNA expression and MCP-1 protein release into medium following ox-LDL stimulation were investigated using quantitative Real time PCR (delta-delta Ct method) and enzyme-linked immunosorbent assay (ELISA), respectively. To examine the receptor specificity of ox-LDL action, HACs were preincubated with anti-human LOX-1 monoclonal antibody (TS92). RESULTS: A time-course study revealed that MCP-1 mRNA expression increased 5.09+/-0.86 fold 12h after ox-LDL stimulation compared to time-0. ox-LDL stimulation increased MCP-1 protein level in conditioned medium in a time-dependent manner. Increased MCP-1 level was evident 6h after stimulation, reaching 830+/-91 pg/ml at 24h (33+/-8 pg/ml at time-0). Dose responses of MCP-1 expression were also evident in mRNA and protein levels. Pretreatment with TS92 markedly suppressed these stimulating effects of ox-LDL, although that with non-specific IgG did not. Native LDL did not affect MCP-1 expression. CONCLUSION: Our results suggest that ox-LDL enhances MCP-1 expression in HACs and supports the hypothesis that ox-LDL is involved in cartilage degeneration.

Congenital aplasia of the extensor muscles of the fingers and thumb associated with generalized polyneuropathy: an autosomal recessive trait.

Three sibs born to normal but consanguinous parents had flexion deformities of the thumb and fingers on one hand and sensory deficit in the other hand. Extensor muscles were absent or vestigial in all of them. Polyneuropathic electrophysiological findings were detected in 4 limbs. This is an apparently autosomal recessive trait previously unreported.

Factors related to degradation of articular cartilage in osteoarthritis: a review.

OBJECTIVES: Osteoarthritis (OA) is a common joint deterioration initiated by multiple factors. To better understand related factors in the development of this disease, we focused on the mechanical stress loaded on articular cartilage. MATERIALS AND METHODS: The anterior cruciate ligaments of rabbit knee joints were transected, and expression of protein kinase C (PKC) examined immunohistochemically. The PKC activator 12-o-tetradecanoyl-phorbol-13-acetate (TPA) was then administered intraarticularly. To determine the involvement of gas mediators, a cartilage defect was made on the medical femoral condyle of rabbit knee joints. Hydrostatic pressure was loaded on the cartilage taken from the surrounding defects, and levels of superoxide anion and nitric oxide (NO) were measured. Bovine chondrocytes were subjected to cyclic mechanical stretch using a Flexercell Strain Instrument. Proteoglycan synthesis and PKC activity were measured. Expression of matrix metalloproteinase (MMP)-3 and tissue inhibitor of metalloproteinase (TIMP)-1 in articular cartilages obtained from OA patients were examined using Northern blots. RESULTS: Chondrocytes from experimentally induced OA were stained positively with anti-alpha-PKC antibody. Intraarticular administration of TPA prevented the development of OA changes. Cyclic tensile stretch loaded on chondrocytes decreased proteoglycan synthesis and PKC activity. Thus, PKC is involved in the stress-mediated degradation of articular cartilage. Cartilage defects led to degradation of surrounding cartilage and to enhanced superoxide anion and NO synthesis. We also noted increased and decreased expressions of MMP-3 and TIMP-1 mRNA in human OA cartilage, respectively. CONCLUSION: PKC, gas mediators (superoxide anion, NO), and proteinases are all involved in OA.

Pertussis toxin-sensitive G proteins as mediators of stretch-induced decrease in nitric-oxide release of osteoblast-like cells.

Mechanical loading plays an important role in regulating bone remodeling, and nitric oxide may be one regulator of this process. To determine how mechanical stress modulates osteoblast function, we loaded cyclic tensile stretch on osteoblast-like cells and measured levels of nitric oxide in the medium. High frequency of stretch at any magnitude inhibited release of nitric oxide; however, low frequency of stretch enhanced its release from the static control. To examine the involvement of G protein (guanine nucleotide-binding regulatory protein) in stress-inhibited release of nitric oxide, we added pertussis toxin, a specific inhibitor of the Gi class, and found that it completely reversed the stress-inhibited release. These data support the idea that pertussis toxin-sensitive G protein is activated in the presence of cyclic tensile stretch.

Cyclic tensile stretch inhibition of nitric oxide release from osteoblast-like cells is both G protein and actin-dependent.

Recent reports indicate the alteration of nitric oxide (NO) synthesis with mechanical stress loaded on the osteoblast and NO is considered to have a significant role in mechanotransduction. We found the involvement of guanine-nucleotide-binding regulatory proteins (G proteins), especially Gi, in stress-inhibited NO release of osteoblast-like cells (JOR:17;593-597, 1999). To determine further the mechanism involved in this process, we measured c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) activity under cyclic tensile stretch loaded on osteoblast-like cells. Cyclic stretch significantly enhanced JNK/SAPK activity and pertussis toxin clearly reversed stress-enhanced JNK/SAPK activity. Cytochalasin D, actin microfilament disrupting reagent, also abolished the stress activation of JNK/SAPK. We propose a model for signaling events induced by cyclic tensile stretch, namely a transmembrane mechanosensor which couples Gi-protein, actin cytoskeleton and finally activates JNK/SAPK activity of osteoblasts.

Bilateral multilevel laminectomy with or without posterolateral fusion for cervical spondylotic myelopathy: relationship to type of onset and time until operation.

The authors retrospectively evaluated the relationship of several preoperative factors in 69 patients who had myelopathy due to multilevel cervical spondylosis without ossification of the posterior longitudinal ligament treated with Kirita's bilateral wide laminectomy. In 34 patients with focal instability or malalignments, posterolateral fusion was also combined. The clinical results at an average follow-up period of 3.5 years (range 1-10 years) after operation in the groups that had and had not undergone fusion were equally satisfactory, and preoperative focal instability was believed to be the sole useful indication for adding posterolateral fusion. The patients were classified in three groups according to the acuteness of the onset. The type of onset and time until operation were found to be the factors most strongly related to prognosis, and clinical outcome was correlated with the duration after onset when plotted as days in the acute, months in the subacute, and years in the insidious onset groups. Wide laminectomy with or without posterolateral fusion is a simple operation that is recommended, provided that it is performed early enough according to the type of onset.

Dorsal root ganglia in the lumbosacral region observed from the axial views of MRI.

A total number of 442 dorsal root ganglia (DRG) in the lumbosacral region of 104 patients were depicted from the axial views of MRI and their localities were classified as intraspinal, intraforaminal, or extraforaminal types. The DRG of the more distal nerve root were located more medially. Asymmetrical locations were observed in 25 pairs of DRG among 221, of which the symptomatic side tended to locate either medially or proximally compared with those on the asymptomatic side.

Progressive scoliosis associated with lateral gaze palsy.

Two cases with progressive scoliosis and lateral gaze palsy were reported. The preoculomotor centers, which are connected by the fasciculus longitudinalis medialis in the brain stem, are deemed to be the common focus for progressive scoliosis and associated visual dysfunction.

Schmorl's nodes on magnetic resonance imaging. Their incidence and clinical relevance.

Schmorl's nodes were observed in 76 (19%) of 400 patients with lumbar symptoms, and in 10 (9.4%) of 106 control patients. In the lumbar group, the highest incidence was 57%, in the second decade of life, and the lowest was 5%, in the sixth decade of life. Using MRI, among both groups, a total number of 218 Schmorl's nodes were observed at 170 disc levels; however, plain x-ray revealed only 73 (33%) of them. There were associated posterior disc herniations at 39 disc levels in 30 cases (39%), most of which were at the L4/5 level. The ratio of the cases showing only Schmorl's nodes to those with associated disc herniations at the same level increased markedly with age. Three of the four teenaged patients with multiple Schmorl's nodes at four or more disc levels had a history of hard sports. Schmorl's nodes, therefore, appear to be a type of vertical disc herniation, and to be an important pathognomonic condition, especially for young people.

Acrodysostosis associated with spinal canal stenosis.

An adult case of acrodysostosis with striking lumbar spinal canal stenosis is reported. She complained of numbness on the right arm, intermittent claudication with numbness on both legs and pain and weakness on the left leg. Although the reduced lumbar interpedicular distance has been reported, no adult case with neurologic symptoms has been reported.

Ossification of the posterior longitudinal ligament. Autosomal recessive trait.

STUDY DESIGN: This study analyzed the mode of inheritance of ossification of the posterior longitudinal ligament (OPLL) from the pedigree of a family. OBJECTIVES: The results were correlated to provide a new mode of inheritance of OPLL. SUMMARY OF BACKGROUND DATA: Although a nation-wide multicenter survey of OPLL has been carried out in 347 subjects and 1030 relatives in Japan since 1981, no parental consanguinity has been reported. METHODS: In the family, three siblings and one other member of a family underwent operations for OPLL in our department, and the clinical information regarding other family members was obtained from interviews with these four patients or relatives. RESULTS: The parents of three affected siblings and another unaffected sister were first cousins, and the father was suspected to be affected as well. CONCLUSION: Transmission of OPLL as an autosomal recessive trait in this family, which has not been reported, is suspected; although, the possibility that it is a dominant trait can not be excluded.

Congenital short femur. Clinical, genetic and epidemiological comparison of the naturally occurring condition with that caused by thalidomide.

Seventy patients with 91 congenital short femora are classified. Deformities resulting maternal Thalidomide treatment are compared with those where Thalidomide was not involved and genetic and epidemiological factors investigated in 50 patients. No essential anatomical difference was found between the two groups of femora but the whole complex of abnormalities differed: the Thalidomide group showed femur-tibia-radius anomalies while the non-Thalidomide garoup had femur-fibula-ulna anomalies, indicating either different aetiological factors or different timing of the insult to the foetus. Some differences between congenital coxa vara and congenital short femur associated with coxa vara are mentioned. Simple hypoplasia of the femur may possibly have a multifactorial genetic background since it is associated with other minor abnormalities of the limbs in these families, whereas environmental factors only are associated with the more severe femoral defects.

Interleukin-4 reversed the Interleukin-1-inhibited proteoglycan synthesis through the inhibition of NO release: a possible involvement of intracellular calcium ion.

Interleukin-1 (IL-1) causes cartilage degradation through nitric oxide (NO) synthesis. Although Interleukin-4 (IL-4) antagonizes the IL-1-mediated cartilage degradation, the precise mechanisms are not clear. We examined the effect of IL-4 on NO synthesis in parallel with intracellular Ca levels ([Ca(2+)]i) and proteoglycan (PG) synthesis. IL-4-inhibited IL-1-enhanced NO release in a dose-dependent manner. IL-1-enhanced [Ca(2+)]i in the chondrocytes, and IL-4 attenuated this increase. IL-4 reversed IL-1-inhibited PG synthesis. Accordingly, IL-4 reversed the IL-1-inhibited PG synthesis through the inhibition of NO release. An increase in [Ca(2+)]i with IL-1 is possibly involved in this action.

An unusual dorsal fracture-dislocation of the proximal interphalangeal joint.

A case of dorsal fracture-dislocation of the proximal interphalangeal joint in which the volar plate had been pulled from its distal attachment without bony or cartilaginous attachments and the lip of the volar plate had also been detached separately and was obstructing full flexion of the joint is presented. A tentative mechanism of causation of this unusual variant of a common injury is suggested.

Possible involvement of the oxidized low-density lipoprotein/lectin-like oxidized low-density lipoprotein receptor-1 system in pathogenesis and progression of human osteoarthritis.

OBJECTIVE: Using human cartilage samples and cultured chondrocytes, to assess the possible involvement of oxidized low-density lipoprotein (ox-LDL) and lectin-like ox-LDL receptor-1 (LOX-1) in pathogenesis and progression of osteoarthritis (OA). METHODS: Thirty-two cartilage samples were obtained from 16 patients with knee OA, and 12 Control samples from six with femoral neck fracture. LOX-1 mRNA expressions in 12 OA and six Control samples were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemistry for ox-LDL and LOX-1 was performed in all samples. The histological OA grade was assessed with the modified Mankin score. The relative percentage of the ox-LDL and LOX-1 immunopositive chondrocytes was calculated in all samples. The effects of ox-LDL on cell viability in cultured human chondrocytes were investigated by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and on proteoglycan synthesis by monitoring [35S] sulfate incorporation. RESULTS: There was a statistically significant difference between mean LOX-1/GAPDH (LOX-1/human glyceraldehyde-3-phosphate dehydrogenase) ratio of OA samples and that of Control samples (40.6%+/-10.3 and 11.9%+/-2.8, respectively, P<0.0001). The mean percentage of ox-LDL-positive cells was 23.0+/-15.7% in OA and 4.3+/-3.7% in Control cells (P=0.0002). The mean percentage of LOX-1-positive cells was 51.7+/-29.5% in OA and 10.0+/-8.1% in Control cells (P<0.0001). Both the ox-LDL immunoreactivity and the LOX-1 immunoreactivity were significantly correlated with the modified Mankin scores (R2=0.67 and 0.48, respectively; P<0.0001 for each). ox-LDL significantly reduced the human chondrocyte viability and proteoglycan synthesis, and pretreatment with anti-human LOX-1 monoclonal antibody reversed these effects. CONCLUSION: The ox-LDL/LOX-1 system may be involved in human OA.

Hypoxia-induced hyaluronan synthesis by articular chondrocytes: the role of nitric oxide.

OBJECTIVE: Articular cartilage is an avascular tissue in which chondrocytes are exposed to hypoxic conditions. We previously demonstrated that reactive oxygen species (ROS) induced apoptosis of chondrocytes. We also demonstrated that nitric oxide (NO) was induced when chondrocytes were exposed to hypoxia and that NO inhibited the ROS-induced apoptosis. Hyaluronan (HA) is a high molecular weight glycosaminoglycan whose antioxidative effects have been reported. The purpose of the present study was to determine whether HA synthesis was induced in chondrocytes exposed to hypoxia, and, if so, whether the hypoxia-induced HA synthesis is regulated by NO. METHODS: Bovine articular chondrocytes were used in this study. Levels of HA were determined by the sandwich enzyme-binding assay. Expression of HA synthase (HAS) was determined with reverse transcription-polymerase chain reaction. The production of NO was examined using the Griess reaction. We also determined inducible nitric oxide synthase (iNOS) enzyme synthesis using the histochemistry and Western blot analysis. RESULTS: Chondrocytes cultured under hypoxic conditions exhibited enhanced HA synthesis. When the NO inhibitors, L-NMMA and L-NAME, were added, the hypoxia-enhanced HA levels in the culture medium were significantly inhibited. CONCLUSIONS: Endogenous NO synthesis plays an important role in hypoxia-enhanced HA synthesis.

Cyclic tensile stretch stimulates the release of reactive oxygen species from osteoblast-like cells.

It is known that the excessive generation of reactive oxygen species (ROS) is a significant factor in tissue injury observed in many disease states. To determine whether extreme levels of mechanical stress applied to osteoblasts enhances ROS synthesis, we loaded cyclic tensile stretch on osteoblast-like HT-3 cells. Cyclic tensile stretch loaded on these cells clearly enhanced ROS synthesis in a time- and magnitude-dependent fashion. Cyclic tensile stretch also enhanced superoxide dismutase (SOD) activity. The disruption of microfilaments with cytochalasin D abolished the stress-induced ROS synthesis. Rotenone, an inhibitor of the mitochondrial electron transport chain, enhanced stress-induced ROS synthesis. These data suggest that actin filament and mitochondria are involved in this action.

Congenital vertical talus: classification with 69 cases and new measurement system.

Sixty-nine cases of congenital vertical talus (CVT) were classified into five groups in association with (1) neural tube defects or spinal anomalies, (2) neuromuscular disorders, (3) malformation syndromes, (4) chromosomal aberrations, and (5) idiopathic CVT unassociated with any of the systemic conditions described above. Forty-four cases of idiopathic CVT were subclassified into four groups: (5A) intrauterine molded or deformed cases, (5B) cases of digitotalar dysmorphism associated with contractile finger abnormalities and genetic inheritance, (5C) patients whose close relatives had CVT or oblique talus (OT) deformity, and (5D) cases unassociated with any skeletal deformity or genetic inheritance. The talar and Calcaneal axis--first metatarsal base angles (TAMBA and CAMBA) are introduced, which enable us to describe not only the obliquity of the talus and calcaneus but also the severity of the dislocation of the talonavicular joint and the contracture of the tendo Achilli. The changing point from flexible OT to rigid CVT is TAMBA of about 60 degrees and CAMBA of 20 degrees, and there are many borderline cases of CVT that could be treated conservatively. For the typical CVT, open reduction should be carried out as promptly as possible if 3 months of corrective casting in extreme equinovarus fails to reduce the TAMBA to 50 degrees.

Turned head--adducted hip--truncal curvature syndrome.

One hundred and eight neonates and infants who showed the clinical triad of a head turned to one side, adduction contracture of the hip joint on the occipital side of the turned head, and truncal curvature, which we named TAC syndrome, were studied. These cases included seven with congenital and five with late infantile dislocations of the hip joint and 14 who developed muscular torticollis. Forty one were among 7103 neonates examined by one of the authors. An epidemiological analysis confirmed the aetiology of the syndrome to be environmental. The side to which the head was turned and that of the adducted hip contracture showed a high correlation with the side of the maternal spine on which the fetus had been lying. TAC syndrome is an important asymmetrical deformity that should be kept in mind during neonatal examination, and may be aetiologically related to the unilateral dislocation of the hip joint, torticollis, and infantile scoliosis which develop after a vertex presentation.