I-Chun Wang

Mesenchymal stem cells expressing baculovirus-engineered BMP-2 and VEGF enhance posterolateral spine fusion in a rabbit model.

BACKGROUND CONTEXT Mesenchymal stem cell (MSC)-based cell therapy and gene transfer have converged and show great potential for accelerating bone healing. Gene therapy can provide more sustained expression of osteogenic factors such as bone morphogenetic protein-2 (BMP-2). We previously demonstrated that low-dose BMP-2 enhanced spinal posterolateral fusion by MSCs in a rabbit model. Herein, we genetically modified rabbit MSCs with a recombinant baculovirus encoding BMP-2 (Bac-CB) and vascular endothelial growth factor (Bac-VEGF) seeded into porous scaffolds to enhance spinal fusion. PURPOSE This study evaluates the success rate of the MSC-based cell therapy and gene transfer approach for single-level posterolateral spine fusion. We hypothesize that combining three-dimensional tricalcium phosphate (TCP) scaffolds and genetically modified allogeneic MSCs with baculovirus-mediated growth factor expression would increase the success rate of spinal fusion. STUDY DESIGN The study design was based on an animal model (approved by the Institutional Animal Care and Use Committee) using 18 adult male New Zealand rabbits. METHODS This study included 18 male New Zealand rabbits, weighing 3.5 to 4 kg. Allogeneic bone marrow-derived MSCs were isolated and genetically modified with Bac-CB and Bac-CV seeded onto TCP scaffolds (MSC/Bac/TCP). The animals were divided into three groups according to the material implanted into the bilateral L4-L5 intertransverse space: TCP scaffold (n=6), MSC/TCP (n=6), and MSC/Bac/TCP (n=6). After 12 weeks, the rabbits were euthanized for radiographic examination, manual palpation, and histologic study. RESULTS Bilateral fusion areas in each animal were evaluated independently. The radiographic fusion rates at 12 sites were 0 of 12 in the TCP scaffold group, 4 of 12 in the MSC/TCP group, and 10 of 12 in the MSC/Bac/TCP group. By manual palpation, there were zero solid fusions in the TCP scaffold group, two solid fusions in the MSC/TCP group, and five solid fusions in the MSC/Bac/TCP group. Fusion rates were significantly greater in the MSC/Bac/TCP group. CONCLUSIONS The results indicate the potential of using baculovirus as a vector for gene/cell therapy approaches to improve bone healing and support the feasibility of using allogeneic MSCs for inducing bone formation and intertransverse process fusion.

Classification and analysis of pathology of the long head of the biceps tendon in complete rotator cuff tears.

BACKGROUND Pathology of the long head of the biceps tendon (LHB) is commonly associated with rotator cuff tears (RCTs). Superior labral anterior-posterior (SLAP) lesions can also occur with RCTs. The purpose of this study was to include SLAP lesions as part of LHB pathology in surgical cases of RCT and define the role of SLAP lesions in RCTs. METHODS We retrospectively evaluated clinical data from 176 cases of complete RCT undergoing surgery. During surgery, the LHB was arthroscopically examined. A modified 6-type classification was used to describe the LHB pathology in these cases: tendinitis, subluxation, dislocation, partial tear, complete rupture and SLAP lesions. The relationship of LHB pathology to different characteristics of RCTs was statistically analyzed. RESULTS Of RCT cases, 33% had Type 1 (tendinitis), 11% had Type 2 (subluxation), 9% had Type 3 (dislocation), 16% had Type 4 (partial tear), 7% had Type 5 (complete rupture) and 6% had Type 6 (SLAP) lesions. The remaining 18% of cases had no obvious LHB pathology. LHB pathology were associated with RCTs of a long duration (> 3 months), large area (> 5 cm(2)), and multiple or subscapularis tendon involvement. Seventy four percent of patients with affected shoulders underwent simultaneous surgery for both LHB pathology and RCTs. CONCLUSION Most patient with RCTs with chronic, massive, and multiple or subscapularis tendon involvement also had LHB injury. SLAP lesions, which we classified as a subgroup of LHB pathology, should be identified during rotator cuff surgery and treated appropriately.

Effect of Hyperbaric Oxygenation on Intervertebral Disc Degeneration An In Vitro Study With Human Lumbar Nucleus Pulposus

Study Design. An in vitro study with degenerated human lumbar intervertebral disc specimens cultured under hyperbaric oxygenation (HBO). Objective. To observe the changes in interleukin (IL)-1&bgr;, prostaglandin (PG)-E2, nitric oxide (NO), cell growth, and apoptosis of the human nucleus pulposus cell (NPC) after HBO. Summary of Background Data. Intervertebral disc degeneration has been demonstrated as related to IL-1&bgr;, PG-E2, NO, and O2 concentration but the actual mechanism is not clear. HBO also has also been reported in the literature to influence changes in IL-1&bgr;, prostaglandin E2, NO, and O2 concentration. However, the direct effect of HBO on the disc cells has not been previously reported. Methods. We collected 12 human lumbar degenerated disc specimens and evaluated the effects of HBO on the cultured NPCs. The amounts of IL-1&bgr;, PG-E2, and NO in the conditioned medium were quantified by enzyme-linked immunosorbent assay and high performance liquid chromatography. Cell growth was measured by increase in cell number. Cell viability and proteoglycan content were evaluated by histologic study using safranin O staining. In situ analysis of apoptosis was performed using Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Results. Our data indicated that HBO treatment inhibited IL-1&bgr;, PG-E2, and NO production but increased cell number and matrix synthesis of cultured NPCs. TUNEL staining showed that HBO treatment suppressed the apoptosis of cultured NPCs. Conclusion. HBO provides a potential treatment modality for disc degeneration.

Effect of hyperbaric oxygenation on intervertebral disc degeneration: An in vivo study with sprague-dawley rats

Study Design. An in vivo study was conducted to test the effect of hyperbaric oxygenation (HBO) on intervertebral disc degeneration in Sprague-Dawley rats. Objective. To observe the changes in intervertebral disc height and levels of glycosaminoglycan, collagen, interleukin-1&bgr; (IL-1&bgr;), prostaglandin E2 (PGE2), and inducible nitric oxide synthase (iNOS) in degenerated intervertebral discs after HBO therapy. Summary of Background Data. Although the involvement of IL-1&bgr;, PGE-2, NO, and low O2 concentration has been demonstrated in intervertebral disc degeneration, the actual mechanism is not clear. It has been reported that HBO influences changes in IL-1&bgr;, PGE-2, NO, and O2 concentration. Previously, a study demonstrated an in vitro positive effect of HBO on the human nucleus pulposus. Thus, an in vivo study in animals was necessary. Methods. Twelve Sprague-Dawley rats were each injected with chondroitinase ABC in 2 proximal intervertebral discs of the tail. After treating with 100% oxygen at 2.5 atmospheres 2 hours per days for 10 days, the change in disc height was determined by radiography. The amounts of PGE-2, iNOS, glycosaminoglycan, and total collagen in the intervertebral disc were quantified by enzyme-linked immunosorbent assay. Tissue morphology and the distribution of glycosaminoglycan, IL-1&bgr;, and iNOS in the intervertebral disc were assessed by histology and immunohistochemistry. The area of IL-1&bgr; in the intervertebral discs was quantified using image analysis software. Results. HBO therapy stopped the decrease in intervertebral disc height, caused an increase in the amount of glycosaminoglycan, and inhibited IL-1&bgr;, PGE-2, and iNOS production. Conclusion. HBO provides a potential treatment modality for intervertebral disc degeneration.

Exposure of Prebiopsy Antibiotics Influence Bacteriological Diagnosis and Clinical Outcomes in Patients With Infectious Spondylitis.

AbstractThe benefit of prebiopsy empirical antibiotics for patients with infectious spondylitis and the effect on clinical outcome are not well known. This study assessed the impact of prebiopsy empirical antibiotics in patients with infectious spondylitis.We retrospectively reviewed 41 adult in-patients with infectious spondylitis who received percutaneous endoscopic debridement and drainage (PEDD) at a tertiary care hospital from August 2002 to August 2012. The average patient age was 55.2 years old and causative bacteria were identified in 32 out of 41 biopsy specimens (78.0%) via the PEDD procedure, which has good diagnostic efficacy comparable to open biopsy.Seventeen patients (41.5%) received prebiopsy empirical antimicrobial therapy, and these patients were less likely to have positive cultures than those who did not receive preoperative antibiotics (64.7% vs 87.5%, P = 0.04). Patients with positive cultures had a better infection control rate (78.1% vs 67.7%) and were less likely to undergo subsequent open surgery. Patients given preoperative antibiotics were more likely to need subsequent open surgery (35.3% vs 16.7%, P = 0.02). From multivariate logistic analysis showed age at diagnosis to be an independent risk factor for the need of further surgery. There were no major complications following the PEDD procedure, except 2 patients had transient paresthesia in the affected lumbar segments.Prebiopsy empirical antibiotic therapy was associated with lower positive culture rate and an increased need for subsequent open surgery. Patients with positive cultures were more likely to have initially adequate treatment, better infection control, and better clinical outcome.

Evaluating Osteogenic Potential of Ligamentum Flavum Cells Cultivated in Photoresponsive Hydrogel that Incorporates Bone Morphogenetic Protein-2 for Spinal Fusion

Regenerative medicine is increasingly important in clinical practice. Ligamentum flava (LF) are typically removed during spine-related surgeries. LF may be a source of cells for spinal fusion that is conducted using tissue engineering techniques. In this investigation, LF cells of rabbits were isolated and then characterized by flow cytometry, morphological observation, and immunofluorescence staining. The LF cells were also cultivated in polyethylene (glycol) diacrylate (PEGDA) hydrogels that incorporated bone morphogenetic protein-2 (BMP-2) growth factor, to evaluate their proliferation and secretion of ECM and differentiation in vitro. The experimental results thus obtained that the proliferation, ECM secretion, and differentiation of the PEGDA-BMP-2 group exceeded those of the PEGDA group during the period of cultivation. The mineralization and histological staining results differed similarly. A nude mice model was utilized to prove that LF cells on hydrogels could undergo osteogenic differentiation in vivo. These experimental results also revealed that the PEGDA-BMP-2 group had better osteogenic effects than the PEGDA group following a 12 weeks after transplantation. According to all of these experimental results, LF cells are a source of cells for spinal fusion and PEGDA-BMP-2 hydrogel is a candidate biomaterial for spinal fusion by tissue engineering.