Effects of the water-holding capability of polyvinyl formal sponges on osteogenic ability in in vivo experiments.

In this study, dextran-coated polyvinyl formal (PVF) sponges with high water-holding capability were developed to increase the osteogenic response in the PVF sponge. The study aimed to estimate the effect of the increased water-holding capability of the sponges on osteogenic capacity at a bone defect site in the rabbit femur epiphysis. Bone formation was evaluated using radiography, microcomputed tomography (CT), and histological analysis at 2, 4, and 6 weeks after implantation. As shown by radiography and micro-CT findings, the dextran-coated PVF sponge without water-holding capability showed little bone formation at all evaluated time points. However, the dextran-coated PVF sponge with high water-holding capability showed increasing bone formation around the implant at 4 and 6 weeks after implantation. Furthermore, as shown by micro-CT quantitative analysis, the grafted PVF sponge with high water-holding capability showed significantly greater values for percentage of bone volume per total volume and mean bone mineral density compared with the grafted PVF sponge without water-holding capability at 4 and 6 weeks after implantation. These results suggest that the dextran-coated PVF sponge with high water-holding capability promoted osteogenesis in vivo. The PVF sponge might be a new biomaterial to be used as a fill material for bone defects.

Angiopoietin-like protein 2 induced by mechanical stress accelerates degeneration and hypertrophy of the ligamentum flavum in lumbar spinal canal stenosis.

Chronic inflammation and subsequent fibrosis induced by mechanical stress play an important role in ligamentum flavum (LF) hypertrophy and degeneration in patients with lumbar spinal canal stenosis (LSCS). Angiopoietin-like protein 2 (Angptl2) is a chronic inflammatory mediator induced under various pathological conditions and increases the expression of TGF-ß1, which is a well-characterized mediator in LF hypertrophy. We investigated whether Angptl2 is induced by mechanical stress, and whether it contributes to LF hypertrophy and degeneration by activating the TGF-ß1 signaling cascade. In this study, we investigated human LF tissue and LF fibroblasts isolated from patients who underwent lumbar surgery. We found that Angptl2 was abundantly expressed in fibroblasts of hypertrophied LF tissues at both the mRNA and protein levels. This expression was not only positively correlated with LF thickness and degeneration but also positively correlated with lumbar segmental motion. Our in vitro experiments with fibroblasts from hypertrophied LF tissue revealed that mechanical stretching stress increases the expression and secretion of Angptl2 via activation of calcineurin/NFAT pathways. In hypertrophied LF tissue, expression of TGF-ß1 mRNA was also increased and TGF-ß1/Smad signaling was activated. Angptl2 expression in LF tissue was positively correlated with the expression of TGF-ß1 mRNA, suggesting cooperation between Angptl2 and TGF-ß1 in the pathogenesis of LF hypertrophy. In vitro experiments revealed that Angptl2 increased levels of TGF-ß1 and its receptors, and also activated TGF-ß1/Smad signaling. Mechanical stretching stress increased TGF-ß1 mRNA expression, which was partially attenuated by treatment with a calcineurin/NFAT inhibitor or Angptl2 siRNA, indicating that induction of TGF-ß1 expression by mechanical stretching stress is partially mediated by Angptl2. We conclude that expression of Angptl2 induced by mechanical stress in LF fibroblasts promotes LF tissue degeneration by activation of TGF-ß1/Smad signaling, which results in LF hypertrophy in patients with LSCS.

Effects of water-holding capability of the PVF sponge on the adhesion and differentiation of rat bone marrow stem cell culture.

The aim of the study is to estimate the effects of the water-holding capability of the polyvinyl formal (PVF) sponges on osteogenic response in vitro experiments. The rat bone marrow stem cells (BMCs) were seeded and cultured for up to 4 weeks under static conditions in osteogenic media to evaluate the adhesion, proliferation, differentiation, and mineralization on the Dextran-coated PVF sponges with or without water-holding capability. The BMCs seeded onto the PVF sponges with water-holding capability showed more significant increases in DNA content, alkaline phosphatase (ALP) activity, osteocalcin content, and calcium deposition than those without water-holding capability. These results suggest that the Dextran-coated PVF sponges with high water-holding capability would have potential uses as both a new scaffold to bone tissue engineering and as a new biomaterial.

Ectopic expression of Ptf1a induces spinal defects, urogenital defects, and anorectal malformations in Danforth's short tail mice.

Danforth's short tail (Sd) is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney.

Spinal multifocal amyloidosis derived from wild-type transthyretin.

Abstract Spinal amyloidosis can occur as a part of systemic amyloidosis or as localized amyloidomas. However, the exact pathogenesis of the spinal amyloidosis remains to be fully understood. Transthyretin (TTR) is an amyloidogenic protein causing two kinds of amyloid diseases. One is senile systemic amyloidosis (SSA), which is caused by wild-type (WT) TTR and primarily affects cardiac functions. The other type is familial amyloidosis, which is mainly induced by mutated TTR. We report here the first case of multifocal spinal TTR amyloidosis derived from WT TTR with radiculomyelopathy and destructive spondylosis. The data and clinical manifestations suggest that the patient may develop SSA. Clinical manifestations of TTR-related amyloidosis may vary more than we previously thought. In spinal amyloidosis, WT TTR is one of the candidate precursor proteins for the disease.

Wild-type transthyretin-derived amyloidosis in various ligaments and tendons.

Transthyretin-derived amyloid deposition is commonly found in intercarpal ligaments of patients with senile systemic amyloidosis. However, the frequency of transthyretin-derived amyloid deposits in ligaments of other tissues remains to be elucidated. This study aimed to determine the frequency of amyloid deposition and the precursor proteins of amyloid found in orthopedic disorders. We studied 111 specimens from patients with carpal tunnel syndrome (flexor tenosynovium specimens), rotator cuff tears (rotator cuff tendon specimens), and lumbar canal stenosis (yellow ligament specimens). To identify amyloid precursor proteins, we used immunohistochemical staining with antibodies that react with transthyretin, immunoglobulin light chain, amyloid A protein, and ß(2)-microglobulin. By means of Congo red staining, we identified 47 (42.3%) amyloid-positive samples, 39 of which contained transthyretin-derived amyloid (18 flexor tenosynovium specimens, 5 rotator cuff tendon specimens, and 16 yellow ligament specimens). Genetic testing and/or clinical findings suggested that all patients with transthyretin amyloid deposits did not have familial amyloidotic polyneuropathy. The occurrence of amyloid deposition in those tissues depended on age. These results suggest that transthyretin-derived amyloid deposits may occur more frequently in various ligaments and tendons than originally expected. In the future, such amyloid deposits may aid determination of the pathogenesis of ligament and tendon disorders in older patients.

The floor plate is sufficient for development of the sclerotome and spine without the notochord.

Danforth'sshort-tail (Sd) mouse is a semi-dominant mutation affecting the development of the vertebral column. Although the notochord degenerates completely by embryonic day 9.5, the vertebral column exists up to the lumber region, suggesting that the floor plate can substitute for notochord function. We previously established the mutant mouse line, Skt(Gt), through gene trap mutagenesis and identified the novel gene, Skt, which was mapped 0.95cM distal to the Sd locus. Taking advantage of the fact that monitoring notochordal development and genotyping of the Sd locus can be performed using the Skt(Gt) allele, we assessed the development of the vertebra, notochord, somite, floor plate and sclerotome in +-+/+-Skt(Gt), Sd-+/+-+, Sd-Skt(Gt)/+-+, Sd-Skt(Gt)/+-Skt(Gt), Sd-+/Sd-+ and Sd-Skt(Gt)/Sd-Skt(Gt) embryos. In Sd homozygous mutants with a C57BL/6 genetic background, the vertebral column was truncated in the 6th thoracic vertebra, which was more severe than previously reported. The floor plate and sclerotome developed to the level of somite before notochord degeneration and the number of remaining vertebrae corresponded well with the level of development of the floor plate and sclerotome. Defects to the sclerotome and subsequent vertebral development were not due to failure of somitogenesis. Taken together, these results suggest that the notochord induced floor plate development before degeneration, and that the remaining floor plate is sufficient for maintenance of differentiation of the somite into the sclerotome and vertebra in the absence of the notochord.

Corresponding scapular pain with the nerve root involved in cervical radiculopathy.

PURPOSE: To correspond scapular pain with the nerve root involved in cervical radiculopathy. METHODS: In the anatomic study, 11 Japanese adult cadavers were dissected to examine the numbers and courses of the cutaneous nerves from C3 to C8 dorsal rami. In the clinical study, 14 men and 11 women aged 34 to 77 years who presented with scapular pain as well as pain, numbness or motor weakness in the upper limbs secondary to cervical radiculopathy were assessed. The involved nerve roots were identified based on the symptoms and signs in the arm and/ or fingers, the radiological diagnosis, and the pain response to cervical nerve root blocks. The sites and characteristics of radicular pain were assessed. RESULTS: In the anatomic study of 22 cutaneous nerves from medial branches of dorsal rami, 18 involved the C5 nerve root, 0 the C6 root, one the C7 root, and 8 the C8 root. In the clinical study, the radicular pain often occurred in the suprascapular region involving the C5 root, in the suprascapular to posterior deltoid region involving the C6 root, in the interscapular region involving the C7 root, and in the interscapular and scapular regions involving the C8 root. All patients with C5 or C8 radiculopathy had both superficial and deep pain, whereas almost all patients with C6 or C7 radiculopathy had deep pain only. No patient had superficial pain only. CONCLUSION: Cervical radiculopathy can cause scapular pain. Pain sites and characteristics are related to the affected nerve root.

Gas-filled intradural cysts of the lumbar spine and the possible pathogenesis.

BACKGROUND CONTEXT: There have only been four reports of gas-filled intradural cysts, and the pathogenesis is unknown. PURPOSE: To document the radiologic and histopathologic features of gas-filled intradural cysts and to discuss the pathogenesis with a review of the literature. STUDY DESIGN: Case report. METHODS: A 67-year-old woman, admitted to our institute, presented with severe right thigh pain. On admission to the institute, enhanced magnetic resonance imaging, showed a cystic lesion in the spinal canal at the L2-L3 level, with an intensity suggesting the presence of gas. An enhanced region around the cyst was noted. Computed tomography after discography also revealed a water-soluble contrast filled the subarachnoid space and area around the cyst, but not inside. RESULTS: The cyst was surgically resected. One of the nerve roots was firmly adherent to the gas-filled cyst. The cyst wall comprised fibrous tissue, including small granulations and herniated disc material. CONCLUSION: Gas-filled intradural cysts are rare. The pathogenesis appears to involve gas in a degenerated intervertebral disc, and spontaneous absorption of herniated disc material.

Analyses of early events during chondrogenic repair in rat full-thickness articular cartilage defects.

In this study we investigated the cellular events that occur during the onset of chondrogenic differentiation during the repair of full-thickness defects of articular cartilage. The V-shaped full-thickness cartilage defects (width 0.7 or 1.5 mm; depth 0.8 mm; length 4 mm) were created in the femoral patellar groove of rats using a custom-built twin-blade device. The time course of the repair response in these cartilage defects was examined using a semi-quantitative histological grading scale. Cartilaginous repair responses failed to occur in the larger 1.5 mm defects, which was covered only by fibrous scar tissue. In contrast, hyaline-like articular cartilage was regenerated concomitantly with the repair of the subchondral bone by 4 weeks in smaller 0.7 mm width defects. Cells in the reparative regions were then characterized by immunohistochemistry and in situ hybridization. Undifferentiated mesenchymal cells migrate into the defects and fill the cavities within 4 days of their creation. The expression of PCNA, N-cadherin, and PTH/PTHrP receptors was induced in cells at the center of the defects, where type II collagen-positive polygonal-shaped cells also begin to appear at day 7. Marrow-derived mesenchymal cells acquire higher levels of proliferative activity in induced cartilage cavities after their initial migration and filling of the smaller 0.7 mm defects. During the regenerative repair of articular cartilage in the rat, there is a distinctive step that appears to be analogous to the precartilaginous condensation that is pivotal during chondrogenesis in development.

L5 radiculopathy caused by a ganglion cyst of the posterior longitudinal ligament in a teenager.

BACKGROUND CONTEXT: There is no previous report on the intraspinal ganglion cyst of the posterior longitudinal ligament in a teenager. PURPOSE: To report a case of radiculopathy caused by a ganglion cyst of the posterior longitudinal ligament in a teenager. STUDY DESIGN: Case report. METHODS: A 17-year-old male with a 4-month history of left L5 radicular pain was found to have an intraspinal cystic lesion causing radicular compression. Magnetic resonance imaging showed a cystic lesion located in the ventral side of the dura. The patient suffered from severe leg pain. As a result, a surgical operation was therefore performed. RESULTS: The cyst containing jelly-like components and a hemorrhage was punctured and then extirpated. It originated from the posterior longitudinal ligament. A histological study revealed the cyst to be without any synovial layers. CONCLUSIONS: This is the first report to describe a ganglion cyst originating from the posterior longitudinal ligament in a teenager. This possible etiology should be kept in mind for any other individuals displaying symptoms of spinal nerve root compression as well as disc herniation.

Three-dimensional tibiofemoral kinematics during deep flexion kneeling in a mobile-bearing total knee arthroplasty.

Achieving very deep flexion after total knee arthroplasty is an important goal of most patients in Japan, Asia, and the Middle East because of floor-sitting lifestyles. Numerous knee arthroplasty designs have been introduced to permit high flexion. We performed an in vivo radiographic analysis of tibiofemoral motions during weight-bearing kneeling in one high-flexion knee arthroplasty design. Twenty knees implanted with a posterior-stabilized rotating-platform knee arthroplasty flexed an average of 126 degrees. The femoral condyles translated posteriorly from extension to maximum flexion. Total posterior condylar translations averaged 11.6 and 4.7 mm for the lateral and medial condyles, respectively. Tibial internal rotation in 19 knees averaged 9 degrees from extension to maximum flexion. Knees implanted with a posterior-stabilized, rotating-platform knee arthroplasty show deep flexion knee kinematics consistent with the implant design intent.

Intervertebral disc cells produce tumor necrosis factor alpha, interleukin-1beta, and monocyte chemoattractant protein-1 immediately after herniation: an experimental study using a new hernia model.

STUDY DESIGN: A new hernia model that simulates human disc herniations was developed in rabbits. The herniated discs were examined by gross appearance and histology and production of tumor necrosis factor alpha, interleukin-1beta, and monocyte chemoattractant protein-1 was investigated. OBJECTIVES: To clarify the early mechanism of spontaneous herniated disc resorption. SUMMARY OF BACKGROUND DATA: Macrophage infiltration in herniated discs is essential for disc resorption. However, surgically removed human herniated disc tissues and existing animal hernia models are not suitable for analyzing the mechanism of macrophage infiltration. Recently, we have demonstrated that intervertebral disc cells are capable of producing monocyte chemoattractant protein-1, a potent macrophage chemoattractant, after stimulation with tumor necrosis factor alpha and interleukin-1beta. METHODS: Intervertebral disc herniations were surgically developed in rabbits using a new technique. The herniated discs were excised at appropriate time intervals after the surgery, and the size and histologic findings were examined. Expressions of tumor necrosis factor alpha, interleukin-1beta, and monocyte chemoattractant protein-1 in herniated discs were investigated immunohistochemically. RESULTS: A new rabbit model of disc herniation was established. The herniated discs spontaneously reduced in size by 12 weeks postsurgery. Infiltrating cells, mainly composed of macrophages, were observed from day 3. Immunohistochemically, intervertebral disc cells in the herniated discs produced tumor necrosis factor alpha and interleukin-1beta on day 1, followed by monocyte chemoattractant protein-1 on day 3. CONCLUSIONS: The new hernia model appears to be very useful for studying herniated disc resorption. Intervertebral disc cells may produce inflammatory cytokines/chemokine immediately after the onset of disc herniation, possibly triggering subsequent macrophage infiltration that leads to disc resorption.