Potential risk of clonally expanded amnion mesenchymal stem cell transplants in contused spinal cords.

OBJECTIVE: Mesenchymal stem/stromal cells (MSC) promote recovery after spinal cord injury (SCI) using adult bone marrow MSC (BM-MSC). Newborn tissues are a convenient source of MSC that does not involve an invasive procedure for cell collection. In this study the authors tested the effects of rat amnion MSC clone (rAM-MSC) in SCI. METHODS: We tested intra-parenchymal injection of a GFP+ rat rAM-MSC clone derived from E18.5 rats in rat SCI and measured behavioral recovery (BBB scores), histology and X-ray opacity. Expression of aggrecan was measured in culture after treatment with TGFß. RESULTS: Injection of rAM-MSC after SCI did not improve BBB scores compared to control vehicle injections; rather they reduced scores significantly over 6 weeks. Spinal cords injected with rAM-MSC were hard in regions surrounding the SCI site, which was confirmed by X-ray opacity. Whole mount imaging of these cords showed minimal tissue loss in the SCI site that occurred in SCI controls, and persistence of GFP+ rAM-MSC. Mason's Trichrome staining of tissue sections showed more intense staining for extracellular matrix (ECM) surrounding and extending beyond the SCI site with injections of rAM-MSC but not in controls. In response to TGF-ß treatment in culture, chondrogenic aggrecan was expressed at higher levels in rAM-MSC than in rBM-MSC, suggesting that the upregulation of TGF-ß in SCI sites may promote chondrogenic differentiation. CONCLUSION: Acute injection after SCI of a clonally expanded rAM-MSC resulted in aberrant differentiation towards a chondrocytic phenotype that disrupts the spinal cord and inhibits behavioral recovery after SCI. It will be critical to ensure that injection of extensively expanded neonatal cells do not differentiate aberrantly in traumatic CNS tissue and disrupt recovery.

Expression of hyaluronidase-4 in a rat spinal cord hemisection model.

STUDY DESIGN: Examination of hyaluronidase-4 (Hyal-4) expression in a rat spinal cord hemisection model. PURPOSE: To determine the status of Hyal-4 expression after hemisection of the spinal cord, and the relationship between its expression and that of chondroitin sulfate proteoglycans (CSPGs). OVERVIEW OF LITERATURE: CSPGs are expressed at the site of spinal cord injury and inhibit axon regeneration. Administration of exogenous chrondroitinase ABC (ChABC), derived from bacteria, digested CSPGs and promoted axonal regrowth. Using a rat hemisection model, we have demonstrated peak CSPGs levels at by 3 weeks after injury but then decreased spontaneously. Could there be an endogenous enzyme similar to ChABC in the spinal cord? It has been suggested that Hyal-4 is involved in CSPG degradation. METHODS: A rat hemisection model was prepared and spinal cord frozen sections were prepared at 4 days and 1, 2, 3, 4, 5, and 6 weeks post-cordotomy and stained for CSPGs and Hyal-4 and subjected to Western blotting. RESULTS: CSPGs appeared at the injury site at 4 days after hemisection, reached a peak after 3 weeks, and then decreased. Hyal-4 was observed around the injury site from 4 days after cordotomy and increased until after 5-6 weeks. Double staining showed Hyal-4 around CSPGs. Western blotting identified a band corresponding to Hyal-4 from 4 days after hemisection. CONCLUSIONS: Hyal-4 was expressed in a rat hemisection model in areas surrounding CSPGs, and as its peak was delayed compared with that of CSPGs. These results suggest the involvement of Hyal-4 in the digestion of CSPGs.

Single, high-dose intraspinal injection of chondroitinase reduces glycosaminoglycans in injured spinal cord and promotes corticospinal axonal regrowth after hemisection but not contusion.

Chondroitin sulfate proteoglycans (CSPGs) inhibit axonal growth, and treatment with chondroitinase ABC promotes axonal regeneration in some models of central nervous system (CNS) injury. The aims of this study were (1) to compare the spatiotemporal appearance of CSPG expression between spinal cord contusion and hemisection models, and (2) to evaluate chondroitinase treatment effects on axonal regrowth in the two injury models. After hemisection, CSPG-immunoreactivity (IR) in the injury site rose to peak levels at 18 days but then decreased dramatically by 49 days; in contrast, CSPG-IR remained high for at least 49 days after contusion. After hemisection, many anterogradely labeled corticospinal tract (CST) axons remained close to CSPG-rich lesion sites, but after contusion, most CST axons retracted by approximately 1 mm rostral from the rostral-most CSPG-rich cyst. Intraspinal injection of chondroitinase at 0, 1, 2, and 4 weeks following injury dramatically reduced CSPG-IR in both injury models within 4 days, and CSPG-IR remained low for at least 3 weeks. After the chondroitinase treatment, many axons grew around the lesion site in hemisected spinal cords but not in contused spinal cords. We propose that improved axonal growth in hemisected spinal cords is due to decreased inhibition resulting from degradation of CSPGs located adjacent to severed CST axons. However, in spinal cord contusions, retracted CST axons fail to grow across gliotic regions that surround CSPG-rich injury sites despite efficient degradation with chondroitinase, suggesting that other inhibitors of axonal growth persist in the gliotic regions.

Stage-specific sagittal spinopelvic alignment changes in osteoarthritis of the hip secondary to developmental hip dysplasia.

STUDY DESIGN: A retrospective, age- and sex-matched radiographic study. OBJECTIVE: To compare the sagittal spinopelvic alignment in patients with hip osteoarthritis (OA) stratified by stage with that of age-matched control groups. SUMMARY OF BACKGROUND DATA: OA of the hip resulting from developmental hip dysplasia could be a cause of low back syndrome. OA of the hip may induce changes in sagittal alignment compared with healthy subjects. METHODS: We studied 53 patients with OA of the hip secondary to developmental hip dysplasia, including 27 at the prearthritic/early stage (age, 34.0 years) and 26 at the advanced/terminal stage (age, 56.3 years). Comparisons were made with healthy females age-matched to each patient group (n = 13 and n = 15, respectively). Lateral roentgenograms of the lumbar spine and the hip joint were obtained in the upright position to determine pelvic inclination, sacral slope angle, lumbar lordotic angle (L1-L5), disc angle of L5/S1, and pelvic angle (by Jackson's method). RESULTS: Patients with pre/early-stage OA tended to have greater anterior pelvic inclination than healthy volunteers, although the difference was not significant. No significant differences were noted for other measurements. Lumbar lordotic and sacral slope angles were significantly greater in patients with advanced/terminal-stage OA than the control. Although lumbar lordotic and sacral slope angles decreased with aging in the healthy subjects, patients with OA retained the lumbar lordotic and sacral slope angles despite progression of OA with age. CONCLUSION: Pelvic inclination tended to increase in pre/early-stage OA patients. In healthy subjects, aging is associated with reduction of lumbar lordotic angle and tendency for posterior inclination of the sacrum. With aging, patients with OA maintained the lumbar lordotic angle and did not develop a posterior sacral slope angle.

Expression of ADAMTS-4 (aggrecanase-1) and possible involvement in regression of lumbar disc herniation.

STUDY DESIGN: Examination of ADAMTS-4 expression, and cellular lineages, distribution, and numbers of ADAMTS-4 (aggrecanase-1) expressing cells in herniated lumbar intervertebral discs. OBJECTIVE: To determine the expression of ADAMTS-4, a metalloproteinase capable of digesting aggrecan, and its role in herniated lumbar intervertebral disc degradation. SUMMARY OF BACKGROUND DATA: Matrix metalloproteinases degrade extracellular matrix of herniated discs, but the mechanism of aggrecan degradation, the major component of intervertebral discs, is poorly understood. METHODS: Surgically resected herniated lumbar intervertebral discs from 22 patients were subclassified into protrusion, subligamentous extrusion, transligamentous extrusion, and sequestration types. Reverse transcriptase polymerase chain reaction, Western blot, and immunohistochemistry were used to evaluate ADAMTS-4 messenger ribonucleic acid and protein expression. RESULTS: Expression of ADAMTS-4 messenger ribonucleic acid and protein was shown in the samples of herniated lumbar intervertebral discs. Immunohistochemical staining showed that ADAMTS-4 was mainly localized in CD68-positive mononuclear cells in granulation and adjacent disc tissues. ADAMTS-4 positive cell counts were significantly higher in transligamentous extrusion and sequestration than protrusion and subligamentous extrusion types. Alcian blue staining showed a decrease of proteoglycan in transligamentous extrusion and sequestration cases. CONCLUSIONS: Macrophages infiltrating granulation and adjacent disc tissues express ADAMTS-4, suggesting its involvement in herniated disc regression.