Molecular alterations in bone marrow mesenchymal stromal cells derived from acute myeloid leukemia patients

The contribution of molecular alterations in bone marrow mesenchymal stromal cells (BM-MSC) to the pathogenesis of acute myeloid leukemia (AML) is poorly understood. Thus we assessed genome-wide genetic, transcriptional and epigenetic alterations in BM-MSC derived from AML patients (AML BM-MSC). Whole-exome sequencing (WES) of AML BM-MSC samples from 21 patients revealed a non-specific pattern of genetic alterations in the stromal compartment. The only mutation present in AML BM-MSC at serial time points of diagnosis, complete remission and relapse was a mutation in the PLEC gene encoding for cytoskeleton key player Plectin in one AML patient. Healthy donor controls did not carry genetic alterations as determined by WES. Transcriptional profiling using RNA sequencing revealed deregulation of proteoglycans and adhesion molecules as well as cytokines in AML BM-MSC. Moreover, KEGG pathway enrichment analysis unravelled deregulated metabolic pathways and endocytosis in both transcriptional and DNA methylation signatures in AML BM-MSC. Taken together, we report molecular alterations in AML BM-MSC suggesting global changes in the AML BM microenvironment. Extended investigations of these altered niche components may contribute to the design of niche-directed therapies in AML.

Anterior cervical discectomy and fusion with a zero-profile integrated plate and spacer device: a clinical and radiological study

Object

Anterior cervical plating decreases the risk of pseudarthrosis following anterior cervical discectomy and fusion (ACDF). Dysphagia is a common complication of ACDF, with the anterior plate implicated as a potential contributor. A zero-profile, stand-alone polyetheretherketone (PEEK) interbody spacer has been postulated to minimize soft-tissue irritation and postoperative dysphagia, but studies are limited. The object of the present study was to determine the clinical and radiological outcomes for patients who underwent ACDF using a zero-profile integrated plate and spacer device, with a focus on the course of postoperative prevertebral soft-tissue thickness and the incidence of dysphagia.

Methods

Using a surgical database, the authors conducted a retrospective analysis of all patients who had undergone ACDF between August 2008 and October 2011. All patients received a Zero-P implant (DePuy Synthes Spine). The Neck Disability Index (NDI) and visual analog scale (VAS) scores for arm and neck pain were documented. Dysphagia was determined using the Bazaz criteria. Prevertebral soft-tissue thickness, spinal alignment, and subsidence were assessed as well.

Results

Twenty-two male and 19 female consecutive patients, with a mean age of 58.4 ± 14.68, underwent ACDF (66 total operated levels) in the defined study period. The mean clinical follow-up in 36 patients was 18.6 ± 9.93 months. Radiological outcome in 37 patients was assessed at a mean follow-up of 9.76 months (range 7.2–19.7 months). There were significant improvements in neck and arm VAS scores and the NDI following surgery. The neck VAS score improved from a median of 6 (range 0–10) to 0 (range 0–8; p < 0.001). The arm VAS score improved from a median of 2 (range 0–10) to 0 (range 0–7; p = 0.006). Immediate postoperative dysphagia was experienced by 58.4% of all patients. Complete resolution was demonstrated in 87.8% of affected patients at the latest follow-up. The overall median Bazaz score decreased from 1 (range 0–3) immediately postoperatively to 0 (range 0–2; p < 0.001) at the latest follow-up. Prevertebral soft-tissue thickness significantly decreased across all levels from a mean of 15.8 ± 4.38 mm to 10.1 ± 2.93 mm. Postoperative lordosis was maintained at the latest follow-up. Mean subsidence from the immediate postoperative to the latest follow-up was 4.1 ± 4.7 mm (p < 0.001). Radiographic fusion was achieved in 92.6% of implants. No correlation was found between prevertebral soft-tissue thickness and Bazaz dysphagia score.

Conclusions

A zero-profile integrated plate and spacer device for ACDF surgery produces clinical and radiological outcomes that are comparable to those for nonintegrated plate and spacer constructs. Chronic dysphagia rates are comparable to or better than those for previously published case series.

Radiological and clinical outcomes following extreme lateral interbody fusion

Object

Extreme lateral interbody fusion (ELIF) is a popular technique for anterior fixation of the thoracolumbar spine. Clinical and radiological outcome studies are required to assess safety and efficacy. The aim of this study was to describe the functional and radiological impact of ELIF in a degenerative disc disease population with a longer follow-up and to assess the durability of this procedure.

Methods

Demographic and perioperative data for all patients who had undergone ELIF for degenerative lumbar disorders between 2007 and 2011 were collected. Trauma and tumor cases were excluded. For radiological outcome, the preoperative, immediate postoperative, and latest follow-up coronal Cobb angle, lumbar sagittal lordosis, bilateral foraminal heights, and disc heights were measured. Pelvic incidence (PI) and PI–lumbar lordosis (PI-LL) mismatch were assessed in scoliotic patients. Clinical outcome was evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS), as well as the Macnab criteria.

Results

One hundred forty-five vertebral levels were surgically treated in 90 patients. Pedicle screw and rod constructs and lateral plates were used to stabilize fixation in 77% and 13% of cases, respectively. Ten percent of cases involved stand-alone cages. At an average radiological follow-up of 12.6 months, the coronal Cobb angle was 10.6° compared with 23.8° preoperatively (p < 0.0001). Lumbar sagittal lordosis increased by 5.3° postoperatively (p < 0.0001) and by 2.9° at the latest follow-up (p = 0.014). Foraminal height and disc height increased by 4 mm (p < 0.0001) and 3.3 mm (p < 0.0001), respectively, immediately after surgery and remained significantly improved at the last follow-up. Separate evaluation of scoliotic patients showed no statistically significant improvement in PI and PI-LL mismatch either immediately postoperatively or at the latest follow-up. Clinical evaluation at an average follow-up of 17.6 months revealed an improvement in the ODI and the VAS scores for back, buttock, and leg pain by 21.1% and 3.7, 3.6, and 3.7 points, respectively (p < 0.0001). According to the Macnab criteria, 84.8% of patients had an excellent, good, or fair functional outcome. New postoperative thigh numbness and weakness was detected in 4.4% and 2.2% of the patients, respectively, which resolved within the first 3 months after surgery in all but 1 case.

Conclusions

This study provides what is to the authors' knowledge the most comprehensive set of radiological and clinical outcomes of ELIF in a fairly large population at a midterm follow-up. Extreme lateral interbody fusion showed good clinical outcomes with a low complication rate. The procedure allows for at least midterm clinically effective restoration of disc and foraminal heights. Improvement in coronal deformity and a small but significant increase in sagittal lordosis were observed. Nonetheless, no significant improvement in the PI-LL mismatch was achieved in scoliotic patients.

Tissue-engineered intervertebral discs: MRI results and histology in the rodent spine

Object

Tissue-engineered intervertebral discs (TE-IVDs) represent a new experimental approach for the treatment of degenerative disc disease. Compared with mechanical implants, TE-IVDs may better mimic the properties of native discs. The authors conducted a study to evaluate the outcome of TE-IVDs implanted into the rat-tail spine using radiological parameters and histology.

Methods

Tissue-engineered intervertebral discs consist of a distinct nucleus pulposus (NP) and anulus fibrosus (AF) that are engineered in vitro from sheep IVD chondrocytes. In 10 athymic rats a discectomy in the caudal spine was performed. The discs were replaced with TE-IVDs. Animals were kept alive for 8 months and were killed for histological evaluation. At 1, 5, and 8 months, MR images were obtained; T1-weighted sequences were used for disc height measurements, and T2-weighted sequences were used for morphological analysis. Quantitative T2 relaxation time analysis was used to assess the water content and T1ρ-relaxation time to assess the proteoglycan content of TE-IVDs.

Results

Disc height of the transplanted segments remained constant between 68% and 74% of healthy discs. Examination of TE-IVDs on MR images revealed morphology similar to that of native discs. T2-relaxation time did not differ between implanted and healthy discs, indicating similar water content of the NP tissue. The size of the NP decreased in TE-IVDs. Proteoglycan content in the NP was lower than it was in control discs. Ossification of the implanted segment was not observed. Histological examination revealed an AF consisting of an organized parallel-aligned fiber structure. The NP matrix appeared amorphous and contained cells that resembled chondrocytes.

Conclusions

The TE-IVDs remained viable over 8 months in vivo and maintained a structure similar to that of native discs. Tissue-engineered intervertebral discs should be explored further as an option for the potential treatment of degenerative disc disease.

Tissue-engineered total disc replacement: final outcomes of a murine caudal disc in vivo study

Consistent with EBSJ's commitment to fostering quality research, we are pleased to feature some of the most highly rated abstracts from the 9th Annual AOSpine North America Fellows Forum in Banff, Canada. Enhancing the quality of evidence in spine care means acknowledging and supporting the efforts of young researchers within our AOSpine North America network. We look forward to seeing more from these promising researchers in the future.

Histology of the bone-cement interface in retrieved Oxford unicompartmental knee replacements

INTRODUCTION

Radiolucent lines (RLL) are commonly seen at the cement-bone interface of knee replacements, yet are poorly understood. Although thin RLL are not associated with implant loosening or poor patient outcome there is still concern that they indicate sub-optimal fixation. The primary study aim is to characterise the histology at the cement-tibia interface in Oxford unicompartmental knee replacement (UKR). The second aim is to assess whether a correlation exists between the presence of a RLL and the type of tissue that predominates at the interface.

METHODS

The radiology and histology of retrieved specimens of the interface from around firmly fixed tibial trays in ten patients undergoing revision between 1 and 19 years after Oxford UKR were studied.

RESULTS

Pre-revision radiographs showed the presence of both full and partial RLL. On contact radiographs of 5mm thick sections of the interface the total percentage of radiolucency ranged from 0 to 90% between patients. There was no consistent pattern for the distribution of radiolucency. Histological assessment demonstrated that under every tibial component there were areas where there was direct contact and interdigitation between bone and cement. The amount of direct bone-cement contact was between 19% and 95% of the tibial tray surface area. The remaining tissue was mainly fibrocartilage but there was also fibrous tissue. The presence of radiolucency was strongly inversely correlated with the percentage of cement-bone contact.

CONCLUSION

This study demonstrates that even with partial or complete RLL seen on radiographs there is still cement-bone contact, thus indicating that there is stable fixation.

Biological intervertebral disc replacement: an in vivo model and comparison of two surgical techniques to approach the rat caudal disc

STUDY DESIGN

Prospective randomized animal study.

OBJECTIVE

To determine a surgical technique for reproducible and functional intervertebral disc replacement in an orthotopic animal model.

METHODS

The caudal 3/4 intervertebral disc (IVD) of the rat tail was approached by two surgical techniques: blunt dissection, stripping and retracting (Technique 1) or incising and repairing (Technique 2) the dorsal longitudinal tendons. The intervertebral disc was dissected and removed, and then either discarded or reinserted. Outcome measures were perioperative complications, spontaneous tail movement, 7T MRI (T1- and T2-sequences for measurement of disc space height (DSH) and disc hydration). Microcomputed tomographic imaging (micro CT) was additionally performed postmortem.

RESULTS

No vascular injuries occurred and no systemic or local infections were observed over the course of 1 month. Tail movements were maintained. With tendon retraction (Technique 1) gross loss of DSH occurred with both discectomy and reinsertion. Tendon division (Technique 2) maintained DSH with IVD reinsertion but not without. The DSH was demonstrated on MRI measurement. A new scoring system to assess IVD appearances was described.

CONCLUSIONS

The rat tail model, with a tendon dividing surgical technique, can function as an orthotopic animal model for IVD research. Mechanical stimulation is maintained by preserved tail movements. 7T MRI is a feasible modality for longitudinal monitoring for the rat caudal disc.

Screw placement accuracy for minimally invasive transforaminal lumbar interbody fusion surgery: a study on 3-d neuronavigation-guided surgery

Purpose The aim of this study was to assess the impact of 3-D navigation for pedicle screw placement accuracy in minimally invasive transverse lumbar interbody fusion (MIS-TLIF). Methods A retrospective review of 52 patients who had MIS-TLIF assisted with 3D navigation is presented. Clinical outcomes were assessed with the Oswestry Disability Index (ODI), Visual Analog Scales (VAS), and MacNab scores. Radiographic outcomes were assessed using X-rays and thin-slice computed tomography. Result The mean age was 56.5 years, and 172 screws were implanted with 16 pedicle breaches (91.0% accuracy rate). Radiographic fusion rate at a mean follow-up of 15.6 months was 87.23%. No revision surgeries were required. The mean improvement in the VAS back pain, VAS leg pain, and ODI at 11.3 months follow-up was 4.3, 4.5, and 26.8 points, respectively. At last follow-up the mean postoperative disc height gain was 4.92 mm and the mean postoperative disc angle gain was 2.79 degrees. At L5-S1 level, there was a significant correlation between a greater disc space height gain and a lower VAS leg score. Conclusion Our data support that application of 3-D navigation in MIS-TLIF is associated with a high level of accuracy in the pedicle screw placement.

Pedicle screw navigation: a systematic review and meta-analysis of perforation risk for computer-navigated versus freehand insertion

Object

In this paper the authors' goal was to compare the accuracy of computer-navigated pedicle screw insertion with nonnavigated techniques in the published literature.

Methods

The authors performed a systematic literature review using the National Center for Biotechnology Information Database (PubMed/MEDLINE) using the Medical Subject Headings (MeSH) terms “Neuronavigation,” “Therapy, computer assisted,” and “Stereotaxic techniques,” and the text word “pedicle.” Included in the meta-analysis were randomized control trials or patient cohort series, all of which compared computer-navigated spine surgery (CNSS) and nonassisted pedicle screw insertions. The primary end point was pedicle perforation, while the secondary end points were operative time, blood loss, and complications.

Results

Twenty studies were included for analysis; of which there were 18 cohort studies and 2 randomized controlled trials published between 2000 and 2011. Foreign-language papers were translated. The total number of screws included was 8539 (4814 navigated and 3725 nonnavigated). The most common indications for surgery were degenerative disease, spinal deformity, myelopathy, tumor, and trauma. Navigational methods were primarily based on CT imaging. All regions of the spine were represented. The relative risk for pedicle screw perforation was determined to be 0.39 (p < 0.001), favoring navigation. The overall pedicle screw perforation risk for navigation was 6%, while the overall pedicle screw perforation risk was 15% for conventional insertion. No related neurological complications were reported with navigated insertion (4814 screws total); there were 3 neurological complications in the nonnavigated group (3725 screws total). Furthermore, the meta-analysis did not reveal a significant difference in total operative time and estimated blood loss when comparing the 2 modalities.

Conclusions

There is a significantly lower risk of pedicle perforation for navigated screw insertion compared with nonnavigated insertion for all spinal regions.

Revision strategies for AxiaLIF

Object

Paracoccygeal transsacral fixation is a novel percutaneous technique for arthrodesis of L5–S1 and L4–5 (Axial Lumbar Interbody Fusion [AxiaLIF]). There are no reports on feasible revision strategies. The goal of this paper is to analyze the surgical details of failed AxiaLIF constructs and to describe revision strategies.

Methods

The medical charts, operative records, and imaging studies of 5 patients with failed multisegment instrumentation using the AxiaLIF device were reviewed.

Results

AxiaLIF constructs were revised in 5 patients with a mean age of 58.4 years. All AxiaLIF devices were part of multisegment fusion constructs for revision surgery and were revised an average of 15 months after implantation. Two AxiaLIF devices were percutaneously retrieved; one because of excessive bone resorption around the AxiaLIF screw, and the other because of chronic hardware infection. In these 2 patients, the anterior column was subsequently stabilized via anterior lumbar interbody fusion. In the other 3 patients, the AxiaLIF device was left in situ. In 2 of these patients the anterior column was stabilized with bilateral L5–S1 posterior lumbar interbody fusion, and in the remaining patient with L4–5 instability the posterior instrumentation only was revised. Revision surgeries were well tolerated. One patient suffered from a wound dehiscence of the back wound.

Conclusions

AxiaLIF devices are safely retrieved using percutaneous technique. Both anterior and posterior revision strategies may be used to achieve anterior column fixation.

The effect of high energy mechanochemical processing on the microstructure, piezoelectric, ferroelectric and mechanical properties of PLZT ceramics

Lead lanthanum zirconate titanate (PLZT) ceramics were synthesized using a high energy mechanochemical processing technique, using tungsten carbide grinding vials and balls. The ceramic powders were prepared using the constituent oxide powders, which were subjected to high energy milling, without the use of any excess PbO in the starting composition. TEM studies revealed the formation of very fine particles of the order of 30 nm, due to the milling effect. Highly dense ceramics could be prepared via sintering which resulted in ultra-high strains in these piezoelectric samples of up to 0.25%, a value which has not been reported hitherto by any other known process. The effect of the reduction in particle size on the microstructure, mechanical and electrical properties of PLZT ceramics were studied and are discussed herein.

Inhaled iron, unlike manganese, is not transported to the rat brain via the olfactory pathway

Iron and manganese share structural, biochemical, and physiological similarities. The objective of this study was to determine whether iron, like manganese, is transported to the rat brain via the olfactory tract following inhalation exposure. Eight-week-old male CD rats were exposed to approximately 0.31 mg Fe per m(3) (mass median aerodynamic diameter = 2.99 microm; geometric standard deviation = 1.15) via inhalation for a target duration of 90 min. Following exposure, rats were euthanized immediately (0) or at 1, 2, 4, 8, or 21 days postexposure. In addition to nasal and regional brain tissues, blood, and viscera were also collected. 59Fe concentrations were determined by gamma spectrometry. Further, heads were collected and frozen, and autoradiograms were prepared to visualize the location of 59Fe from the nose to the brain. Finally, olfactory mucosa samples collected at 0, 2, 4, and 21 days postexposure were further analyzed using high-performance liquid chromatography (HPLC) plus gamma spectroscopy to determine the association between 59Fe and transferrin. Data obtained from gamma spectrometry revealed that most of the iron remained in the nasal regions of the olfactory system and that less than 4% of iron deposited on the olfactory mucosa was observed in the olfactory bulb. Autoradiograms confirmed the data obtained from gamma spectrometry. 59Fe activity was absent in the olfactory regions of the brain even 4 days postexposure. Further, HPLC-gamma spectroscopy analyses indicated that 59Fe in the olfactory mucosa was coeluted with transferrin. Hence iron, unlike manganese, is not readily transported to the brain via the olfactory tract.

Androgenesis from Festuca pratensis x Lolium multiflorum amphidiploid cultivars in order to select and stabilize rare gene combinations for grass breeding

Androgenesis using amphidiploid cultivars of Festuca pratensis x Lolium multiflorum as parents, overcame earlier problems that gave rise to widespread plant sterility amongst androgenic Festulolium populations. Two Festuca pratensis x Lolium multiflorum (2n = 4x = 28) cultivars, Sulino and Felopa, were highly amenable to androgenesis and 10% of plants, including some novel androgenic genotypes, had sufficient fertility to produce progeny and further generations. The genomes of amphidiploid cultivars, which represent the F8 generation, were the result of considerable intergeneric chromosome recombination. Moreover, during cultivar development, natural and breeders' selection pressures had led to the assembly of gene combinations that conferred good growth characters and fertility with the removal of putative deleterious gene combinations. Over 80% of the androgenic plants derived from the amphidiploid F. pratensis x L. multiflorum (2n = 4x = 28) had 14 chromosomes and were likely to be dihaploids with a single genome of Lolium and of Festuca. In contrast, hybrids of F. pratensis x L. multiflorum (2n = 2x = 14) found naturally are invariably sterile. Structural reorganization within the genomes of the androgenic Festulolium plants had restored fertility in genotypes expected to contain the haploid genome of Lolium and Festuca. This provided opportunities for their future incorporation in breeding programmes and the development of fertile diploid Lolium-Festuca hybrids. Amongst the androgenic plants, Festulolium genotypes were recovered that conferred excellent drought resistance or freezing tolerance and were thought to be highly suitable for entry into plant breeding programmes.

Effect of hyperinsulinaemia on the function of the pituitary-adrenal axis in healthy man

OBJECTIVE

Circulating insulin levels in themselves have been reported to influence the counter-regulatory hormone response to hypoglycaemia in man. The effect of insulin on a specific aspect of this response was examined during euglycaemia by stimulating the pituitary-adrenal axis with human corticotrophin-releasing hormone (CRH).

SUBJECTS

Eight healthy males.

DESIGN

Following an overnight fast, insulin was infused at 15 (low) and 60 (high) mU/kg/h from 0900 h for 180 minutes on separate occasions in random order. On each occasion, blood glucose was clamped at euglycaemia, and 1 microgram/kg (i.v. bolus) human CRH was administered at 120 minutes.

MEASUREMENTS

Circulating hormone concentrations were determined by radioimmunoassay. Peak cortisol and ACTH responses were compared for the two study conditions.

RESULTS

Mean serum insulin levels were threefold higher during the high compared with the low insulin infusion (mean difference 320 pmol/l, 95% confidence interval (CI) 150-490, P < 0.001). Blood glucose levels during the clamps were comparable (mean difference 0.15 mmol/l, 95% CI 0-0.63). Plasma cortisol levels increased following CRH, although the peak concentration was significantly lower during the high insulin infusion (mean difference 36 nmol/l, CI 0-110, P < 0.02). However, peak ACTH levels were comparable for the two insulin levels (mean difference 8 ng/l (1.8 pmol/l), CI 0-50).

CONCLUSIONS

The peak cortisol response to CRH was diminished at the higher circulating insulin levels. This was not dependent upon concurrent hypoglycaemia and did not appear to be mediated at the level of the pituitary gland.

Herpes simplex virus encephalitis during childhood: importance of brain biopsy diagnosis

Twelve consecutive pediatric patients 1 day to 11 years of age with suspected herpes simplex virus (HSV) encephalitis underwent brain biopsy. Five were proved to have HSV encephalitis; seven had subdural empyema, malignant glioma, enteroviral encephalitis, (one each), and presumed viral encephalitis, non-HSV (four). Neither epidemiologic, clinical, nor noninvasive laboratory tests were able to help differentiate the two groups of patients. The EEG was more sensitive than the CT scan in demonstrating focal lesions in early HSV encephalitis. In patients with HSV encephalitis, the mean time from hospital admission to appropriate antiviral chemotherapy was 3 days, and the outcome of HSV encephalitis was uniformly poor. In patients with febrile encephalitis-like syndromes with CSF pleocytosis, focal neurologic signs, or other localizing test results (EEG, CT), anticipatory antiviral chemotherapy and brain biopsy are the only hope to prevent the poor outcome associated with HSV encephalitis, to exclude other treatable conditions, and to avoid multiple types of unnecessary empiric therapies.