Development of a standardized histopathology scoring system for intervertebral disc degeneration and regeneration in rabbit models-An initiative of the ORSspine section

BACKGROUND

The rabbit lumbar spine is a commonly utilized model for studying intervertebral disc degeneration and for the pre-clinical evaluation of regenerative therapies. Histopathology is the foundation for which alterations to disc morphology and cellularity with degeneration, or following repair or treatment are assessed. Despite this, no standardized histology grading scale has yet been established for the spine field for any of the frequently utilized animal models.

AIMS

The purpose of this study was to establish a new standardized scoring system to assess disc degeneration and regeneration in the rabbit model.

MATERIALS AND METHODS

The scoring system was formulated following a review of the literature and a survey of spine researchers. Validation of the scoring system was carried out using images provided by 4 independent laboratories, which were graded by 12 independent graders of varying experience levels. Reliability testing was performed via the computation of intra-class correlation coefficients (ICC) for each category and the total score. The scoring system was then further refined based on the results of the ICC analysis and discussions amongst the authors.

RESULTS

The final general scoring system involves scoring 7 features (nucleus pulposus shape, area, cellularity and matrix condensation, annulus fibrosus/nucleus pulposus border appearance, annulus fibrosus morphology, and endplate sclerosis/thickening) on a 0 (healthy) to 2 (severe degeneration) scale. ICCs demonstrated overall moderate to good agreement across graders. An addendum to the main scoring system is also included for use in studies evaluating regenerative therapeutics, which involves scoring cell cloning and morphology within the nucleus pulposus and inner annulus fibrosus.

DISCUSSION

Overall, this new scoring system provides an avenue to improve standardization, allow a more accurate comparison between labs and more robust evaluation of pathophysiology and regenerative treatments across the field.

CONCLUSION

This study developed a histopathology scoring system for degeneration and regeneration in the rabbit model based on reported practice in the literature, a survey of spine researchers, and validation testing.

A perspective on the ORS Spine Section initiative to develop a multi-species JOR Spine histopathology series

This perspective summarizes the genesis, development, and potential future directions of the multispecies JOR Spine histopathology series.

A guide to reducing adverse outcomes in rabbit models of sciatic nerve injury

Background

Peripheral nerve damage can have debilitating consequences. Rabbit sciatic nerve transection models allow the effective evaluation of surgical repair strategies for large nerve gaps. Despite advantages in size, ease of handling, and functional utility, rabbits can suffer from a number of side effects that affect animal welfare and the quality of scientific inquiry. Such side-effects, which include pressure ulcers and traumatic damage to the foot, are primarily a consequence of insensitivity of the distal hindlimb following sciatic nerve injury. In this study, we present a number of methodologies for identifying, treating, and preventing unintended adverse effects in rabbit sciatic nerve injury models.

Results

First, we categorize pressure ulcers according to their severity and describe the deployment of a padded bandaging technique to enable ulcer healing. We also introduce a proactive bandaging approach to reduce the likelihood of pressure ulcer formation. Second, we define phenotypes that distinguish between foot injuries resulting from self-mutilation (autotomy) from those caused by incidental traumatic injury secondary to sensori-motor damage. Finally, we detail an effective strategy to reduce the usage of Elizabethan collars; through a gradual weaning protocol, their usefulness in preventing autotomy is retained, while their propensity to impede rabbit grooming and cause abrasion-injury to the neck region is minimized.

Conclusions

We suggest that application of these methods offer a practical and systematic approach to avoid adverse side effects associated with rabbit sciatic nerve damage, enabling improved animal welfare and scientific outcomes in a powerful nerve injury model.

A novel orexin antagonist from a natural plant was discovered using zebrafish behavioural analysis

OBJECTIVE

Phenotypic screening is one of the most practical approaches to the identification of mediators of behaviour, since it is difficult to model brain function in vitro, at a cellular level. We used a zebrafish (Danio rerio) behavioural assay to discover novel, natural, neuroactive compounds.

MATERIALS AND METHODS

A zebrafish behavioural assay was performed for seven natural compounds, obtained from plants. The behavioural profiles were compared to those of known psychoactive drugs. We characterised a natural compound exhibiting a behaviour profile similar to that of suvorexant, using in silico, in vitro and microarray expression analysis.

RESULTS

The behavioural analysis performed in this study classified central nervous system drugs according to their mechanism. Zebrafish treated with a natural compound, 8b-(4'-Hydroxytigloyloxy) costunolide (8b), showed behaviour profiles similar to those of zebrafish treated with suvorexant, a known orexin antagonist. This behavioural assay was validated using in silico and in vitro assays, which revealed that the new compound was a dual orexin receptor antagonist. In addition, transcriptome analysis suggested that 8b might regulate the nuclear factor-κB (NF-κB) related pathway.

CONCLUSIONS

We conclude that zebrafish phenotypic screening, combined with in silico assays and gene expression profiling, is a useful strategy to discover and characterize novel therapeutic compounds, including natural products.

Three-dimensional computed tomographic evaluation of lateral lumbar interbody fusion: morphometric change of intervertebral structure

PURPOSE

Two-dimensional (2D) analyses of intervertebral disc (IVD) height and foramen measurements following lateral lumbar interbody fusion (LLIF) have been reported. However, three-dimensional (3D) morphometric analysis of intervertebral structure using 3D computed tomography (3D CT) provides increased precision for measuring morphological changes. The purpose of this study was to evaluate 3D changes of lumbar IVD height and foramen diameter in degenerative lumbar disease patients following LLIF.

METHODS

Subject-based 3D CT lumbar models were created for 26 patients before and following LLIF. IVD height (whole and five anatomical zones) and foramen diameter (minimum and maximum) were measured based on the model using custom software. The sagittal placement of cages (SPC) and cross-sectional area of the thecal sac (CSA) were measured. Changes in these parameters by LLIF were quantified and statistically analysed.

RESULTS

Following LLIF, disc height increased by an average of 2.9 mm (P < 0.01). Post-operative measurements of both minimum and maximum diameters of the foramen were significantly increased by 1.0 mm and 1.9 mm, respectively (P < 0.01). Change in maximum foramen diameter was significantly correlated with change in disc height (P < 0.05). The SPC was significantly correlated with the changes in disc height and foraminal diameters (P < 0.05, respectively). No significant change between the change in disc height and CSA was found.

CONCLUSION

This preliminary study quantifies disc height and foramen diameter changes in 3D following LLIF. The presented data provide baseline intervertebral changes for future comparisons with follow-up studies and clinical outcomes.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Superselective intra-arterial chemoradiotherapy using altered blood flow compared to conventional systemic chemoradiotherapy for locally advanced oral squamous cell carcinoma: a single-center retrospective study

PURPOSE

To evaluate the efficacy and safety of superselective intra-arterial (IA) chemoradiotherapy with cisplatin and transcatheter arterial embolization (TAE) on advanced oral cancer, and to compare it with that of systemic chemoradiotherapy.

MATERIALS AND METHODS

This single-center retrospective study included 23 consecutive patients with locally advanced oral squamous cell carcinoma from November 2011 to November 2019. Of these, 15 received superselective IA cisplatin chemoradiotherapy with altered blood flow in the branches of the external carotid artery, and eight received systemic chemoradiotherapy. Medical charts were reviewed for the evaluation of patient data, drug toxicity, and antitumor efficacy.

RESULTS

Local control rate for the superselective IA infusion group, who underwent 6-7 cycles was significantly higher than that of the systemic chemotherapy group (11/13, 85% vs 3/8, 38%; p = 0.04). Regional control, locoregional control, disease-free survival, and overall survival rates were not significantly different between the groups (p = 0.15-0.907). Acute toxicity rates of grade 3 or higher were not significantly different between the IA and IV chemotherapy groups (p = 0.221).

CONCLUSION

Superselective IA chemoradiotherapy with cisplatin using altered blood flow in the branches of the external carotid artery with TAE may be useful for inoperable oral cancer.

Correlation between the magnetic resonance imaging features of squamous cell carcinoma of the buccal mucosa and pathologic depth of invasion

OBJECTIVE

The objective of this study was to determine correlations between magnetic resonance imaging (MRI) features including radiologic depth of invasion (r-DOI) and pathologic DOI (p-DOI) of squamous cell carcinoma of the buccal mucosa.

STUDY DESIGN

In total, 31 lesions were retrospectively evaluated. MRI findings included detectability, buccinator muscle invasion (positive: BMI+, negative: BMI-), buccal fat pad invasion (positive: BFPI+, negative: BFPI-), and r-DOI measured on T2-weighted images (T2-DOI) and contrast-enhanced T1-weighted images (CET1-DOI). These findings were compared to the p-DOI of the tumors.

RESULTS

The p-DOI values of undetectable lesions were smaller than those of detectable lesions (P < .001), and the cutoff value was 1 mm. BMI+ and BFPI+ lesions had significantly larger p-DOI values than the corresponding BMI- and BFPI- lesions (P < .001), with cutoff values of 5 and 6 mm, respectively. The correlation coefficient between CET1-DOI and p-DOI was 0.68 (P < .001). CET1-DOI values were larger than p-DOI (P < .001) and the average difference between them was 3.4 mm. T2-DOI was inconclusive in 50% of cases. Interobserver agreements of MRI evaluation were good to very good.

CONCLUSION

MRI-derived parameters were useful in estimating p-DOI and may be helpful in predicting the depth of invasion of tumors and the risk of lymph node metastasis.

Lactulose ingestion causes an increase in the abundance of gut-resident bifidobacteria in Japanese women: a randomised, double-blind, placebo-controlled crossover trial

The genus Bifidobacterium comprises various bacterial species, and the complement of species within the human intestinal tract differs from individual to individual. The balance of these bifidobacterial species remains poorly understood, although it is known that the abundance of bifidobacteria increases following the ingestion of prebiotics. We previously conducted a randomised, placebo-controlled, double-blind, crossover study of 2 g/day lactulose ingestion for 2 weeks in 60 Japanese women. To study the effect of lactulose ingestion on each bifidobacterial species, here, we measured the abundance of each of the principal bifidobacterial species. After lactulose ingestion, the log cell counts of the Bifidobacterium adolescentis group (8.97±0.08 vs 9.39±0.08, P=0.0019), Bifidobacterium catenulatum group (9.45±0.10 vs 9.65±0.10, P=0.0032) and Bifidobacterium longum group (9.01±0.07 vs 9.29±0.07, P=0.0012) were significantly higher than in the placebo ingestion control group. However, the log cell counts were similar for Bifidobacterium breve (8.12±0.12 vs 8.33±0.12, P=0.20), Bifidobacterium bifidum (9.08±0.12 vs 9.42±0.14, P=0.095) and Bifidobacterium animalis subspecies lactis (8.65±0.53 vs 8.46±0.46, P=0.77). Cluster analysis of the log cell count data at the bifidobacterial species level revealed three distinct clusters, but the combinations and ratios of the constituent bifidobacteria were not affected by lactulose ingestion. Furthermore, principal coordinate analysis of the intestinal microbiota in the lactulose and placebo ingestion groups using Illumina MiSeq showed no significant differences in the intestinal microbiota as a whole. These results suggest that 2 g/day lactulose ingestion for 2 weeks significantly increases the abundance of intestinal bifidobacteria, but does not affect the intestinal microbiota as a whole.

High-Contrast Lumbar Spinal Bone Imaging Using a 3D Slab-Selective UTE Sequence

Ultra-short echo time (UTE) MRI with post-processing is a promising technique in bone imaging that produces a similar contrast to computed tomography (CT). Here, we propose a 3D slab-selective ultrashort echo time (UTE) sequence together with image post-processing to image bone structures in the lumbar spine. We also explore the intermodality agreement between the UTE and CT images. The lumbar spines of two healthy volunteers were imaged with 3D UTE using five different resolutions to determine the best imaging protocol. Then, four patients with low back pain were imaged with both the 3D UTE sequence and CT to investigate agreement between the imaging methods. Two other patients with low back pain were then imaged with the 3D UTE sequence and clinical conventional T₁-weighted and T₂-weighted fast spin-echo (FSE) MRI sequences for qualitative comparison. The 3D UTE sequence together with post-processing showed high contrast images of bone and high intermodality agreement with CT images. In conclusion, post-processed slab-selective UTE imaging is a feasible approach for highlighting bone structures in the lumbar spine and demonstrates significant anatomical correlation with CT images.

Role of Curcuminoids and Tricalcium Phosphate Ceramic in Rat Spinal Fusion

Despite considerable research effort, there is a significant need for safe agents that stimulate bone formation. Treatment of large or complex bone defects remains a challenge. Implantation of small molecule-induced human bone marrow-derived mesenchymal stromal cells (hBMSCs) on an appropriate tricalcium phosphate (TCP) scaffold offers a robust system for noninvasive therapy for spinal fusion. To show the efficacy of this approach, we identified a small molecule curcuminoid that when combined with TCP ceramic in the presence of hBMSCs selectively induced growth of bone cells: after 8- or 25-day incubations, alkaline phosphatase was elevated. Treatment of hBMSCs with curcuminoid 1 and TCP ceramic increased osteogenic target gene expression (i.e., Runx2, BMP2, Osteopontin, and Osteocalcin) over time. In the presence of curcuminoid 1 and TCP ceramic, osteogenesis of hBMSCs, including proliferation, differentiation, and mineralization, was observed. No evidence of chondrogenic or adipogenic potential using this protocol was observed. Transplantation of curcuminoid 1-treated hBMSC/TCP mixtures into the spine of immunodeficient rats showed that it achieved spinal fusion and provided greater stability of the spinal column than untreated hBMSC-TCP implants or TCP alone implants. On the basis of histological analysis, greater bone formation was associated with curcuminoid 1-treated hBMSC implants manifested as contiguous growth plates with extensive hematopoietic territories. Stimulation of hBMSCs by administration of small molecule curcuminoid 1 in the presence of TCP ceramic afforded an effective noninvasive strategy that increased spinal fusion repair and provided greater stability of the spinal column after 8 weeks in immunodeficient rats. Impact statement Bone defects only slowly regenerate themselves in humans. Current procedures to restore spinal defects are not always effective. Some have side effects. In this article, a new method to produce bone growth within 8 weeks in rats is presented. In the presence of tricalcium phosphate ceramic, curcuminoid-1 small molecule-stimulated human bone marrow-derived mesenchymal stromal cells showed robust bone cell growth in vitro. Transplantation of this mixture into the spine showed efficient spinal fusion in rats. The approach presented herein provides an efficient biocompatible scaffold for delivery of a potentially clinically useful system that could be applicable in patients.

P2477Assessment of intraventricular flow dynamics in acute heart failure studied by Vector Flow Mapping

Background

Although left ventricular (LV) flow dynamics should be closely related to LV morphology and function, little is known about how heart failure (HF) changes it. Pathline Analysis (PA), a recently developed software based on Vector Flow Mapping (VFM, Hitachi), enables us to trace the virtual blood particles entering to the LV in diastole and being ejected in systole. We investigated the change of flow dynamics in HF induced in dogs using PA.

Methods

In 15 open-chest dogs, HF was induced by intracoronary injection of microspheres. Color Doppler images of apical long-axis view were acquired using Prosound F75 (Hitachi) before and after HF and were analyzed by PA. We calculated the ratio of the numbers of entering particles in diastole and ejected particles in systole (ejection rate) and the distance reached by the particles in diastole corrected by the LV long-axis diameter (propagation distance). Apical and basal short axis images were acquired using GE Vivid E9 and were analyzed for peak rotation and peak twist.

Results

After inducing HF, LV end-diastolic pressure increased from 6±2 to 15±5 mmHg (p<0.001) and ejection fraction (EF), apical peak rotation and peak twist decreased significantly (EF; 58±5 to 36±8%, apical peak rotation; 14±5 to 3±2 degree, peak twist; 19±5 to 6±3 degree, p<0.05, respectively). PA showed most of the entering particles to the LV were ejected in the following systole at the control stage, but in HF, a significant part of the entering particles were not ejected and remained in the LV (Figure). Ejection rate decreased from 50±11 to 26±11% (p<0.001) and the propagation distance decreased from 85±9 to 66±13% (p<0.001) after inducing HF. There were significant relationships between indices obtained by PA and EF and peak twist (Table).

Conclusion

A significant part of inflow is not ejected directly to the outflow in the next systole and remains in the LV in HF, suggesting inefficient flow dynamics.

P1470Myocardial dysfunction index: a novel myocardial strain parameter for diagnosing myocardial ischemia

Background and purpose

Peak systolic strain (ε-sys) derived from speckle tracking echocardiography (STE) is a useful parameter for assessing regional contractile dysfunction during acute ischemia. However, low ε-sys does not always indicate myocardial ischemia because of its relatively large variation in segmental normal ranges and intervendor differences. Therefore, comparison of strain before and after an ischemic event and demonstration of a decrease in ε-sys should be necessary to confirm myocardial ischemia, which is not always possible in clinical situations. It is well known that early systolic lengthening (ESL) and post-systolic shortening (PSS) occur during acute ischemia. We hypothesized that ESL and PSS would correlate with the decrease in ε-sys and integrated analysis of ESL and PSS could be useful to diagnose the presence of myocardial ischemia.

Methods

2D short-axis or 3D full-volume images were acquired by Artida at baseline, during flow-limiting stenosis (mean 50±20% flow reduction), and during complete occlusion of the left circumflex coronary artery in 22 dogs (2D-STE = 12, 3D-STE = 10).Circumferential strain was analyzed in the center of risk area, and the absolute value of peak systolic strain (ε-sys), post-systolic strain index (PSI) as a parameter of PSS, and early systolic strain index (ESI) as a parameter of ESL were measured. A new parameter, myocardial dysfunction index (MDI), which was calculated as follows: (ESL amplitude + PSS amplitude)/maximal strain amplitude during the cardiac cycle, was also calculated. The difference in ε-sys between at baseline and during ischemia (Δε-sys) was measured and the diagnostic accuracy for estimating Δε-sys < −3% was assessed by the receiver operating characteristics (ROC) curve analysis.

Results

During ischemia, ε-sys decreased from 19±3 to 12±6% and MDI increased from 2±4 to 27±30%. MDI was significantly correlated with Δε-sys (2D-STE: r=−0.80, 3D-STE: r=−0.83, p<0.01, respectively) (Figure). The area under the curve (AUC) of MDI for estimating Δε-sys < −3% tended to be larger than those of ESI and PSI (MDI: 0.9, ESI: 0.73, PSI: 0.85).

Figure 1

Conclusions

The novel parameter, MDI was correlated with the decrease in ε-sys during acute ischemia. Integrated analysis of ESL and PSS may be useful for diagnosing the presence of myocardial ischemia.

A novel magnetic resonance imaging postprocessing technique for the assessment of intervertebral disc degeneration-Correlation with histological grading in a rabbit disc degeneration model

INTRODUCTION

Estimation of intervertebral disc degeneration on magnetic resonance imaging (MRI) is challenging. Qualitative schemes used in clinical practice correlate poorly with pain and quantitative techniques have not entered widespread clinical use.

METHODS

As part of a prior study, 25 New Zealand white rabbits underwent annular puncture to induce disc degeneration in 50 noncontiguous lumbar discs. At 16 weeks, the animals underwent multi-echo T2 MRI scanning and were euthanized. The discs were stained and examined histologically. Quantitative T2 relaxation maps were prepared using the nonlinear least squares method. Decay Variance maps were created using a novel technique of aggregating the deviation in the intensity of each echo signal from the expected intensity based on the previous rate of decay.

RESULTS

Decay Variance maps showed a clear and well demarcated nucleus pulposus with a consistent rate of decay (low Decay Variance) in healthy discs that showed progressively more variable decay (higher Decay Variance) with increasing degeneration. Decay Variance maps required significantly less time to generate (1.0 ± 0.0 second) compared with traditional T2 relaxometry maps (5 (±0.9) to 1788.9 (±116) seconds). Histology scores correlated strongly with Decay Variance scores (r = 0.82, P < .01) and weakly with T2 signal intensity (r = 0.32, P < .01) and quantitative T2 relaxometry (r = 0.39, P < .01). Decay Variance had superior sensitivity and specificity for the detection of degenerate discs when compared to T2 signal intensity or Quantitative T2 mapping.

CONCLUSION

Our results show that using a multi-echo T2 MRI sequence, Decay Variance can quantitatively assess disc degeneration more accurately and with less image-processing time than quantitative T2 relaxometry in a rabbit disc puncture model. The technique is a viable candidate for quantitative assessment of disc degeneration on MRI scans. Further validation on human subjects is needed.

Prebiotic effect of two grams of lactulose in healthy Japanese women: a randomised, double-blind, placebo-controlled crossover trial

Sixty healthy Japanese women with a defaecation frequency of 2-4 times/week participated in this randomised, double-blind crossover trial. Participants received 2 g/day lactulose for 2 weeks and placebo in a random order, separated by a washout period of 3 weeks. Eight participants were excluded who did not satisfy the conditions, and therefore data from 52 were analysed. The primary outcome was defaecation frequency and the secondary outcomes were the number of defaecation days, faecal consistency, faecal volume, and the number and percentage of Bifidobacterium in faeces. The defaecation frequency (times/week) was significantly higher during lactulose (4.28±0.23) than placebo (3.83±0.23) treatment (delta (Δ) 0.45 [95% confidence interval (CI) 0.10-0.80], P=0.013). The defaecation days (days/week) was significantly higher during lactulose (3.77±0.17) than placebo (3.47±0.17) treatment (Δ0.30 [95% CI 0.04-0.56], P=0.024). Faecal consistency using the Bristol Stool Scale (/defaecation) was significantly higher during lactulose (3.84±0.10) than placebo (3.68±0.10) treatment (Δ0.16 [95% CI 0.00-0.31], P=0.044). Faecal volume (/week) was significantly higher during lactulose (21.73±3.07) than placebo (17.65±3.07) treatment (Δ4.08 [95% CI 0.57-7.60], P=0.024). The number of Bifidobacterium in faeces (log colony forming units/g faeces) was significantly higher during lactulose (9.53±0.06) than placebo (9.16±0.06) treatment (Δ0.37 [95% CI 0.23-0.49], P<0.0001). The percentage of Bifidobacterium in faeces was also significantly higher during lactulose (25.3±1.4) than placebo (18.2±1.4) treatment (Δ7.1 [95% CI 2.9-11.4], P=0.0014). Finally, straining at defaecation (/defaecation) during lactulose (3.62±0.24) treatment was significantly lower than during placebo (3.97±0.24) treatment (Δ0.35 [95% CI -0.69 – -0.02], P=0.037). No significant difference was observed between lactulose and placebo with regard to flatulence. Severe adverse effects did not occur. Thus, oral ingestion of 2 g/day lactulose had a prebiotic effect, increasing the number and percentage of bifidobacteria in faeces, softening the faeces, and increasing defaecation frequency, but without increasing flatulence.

Platelet-rich plasma in the management of chronic low back pain: a critical review

Low back pain (LBP) is now regarded as the first cause of disability worldwide and should be a priority for future research on prevention and therapy. Intervertebral disc (IVD) degeneration is an important pathogenesis of LBP. Platelet-rich plasma (PRP) is an autologous blood concentrate that contains a natural concentration of autologous growth factors and cytokines and is currently widely used in the clinical setting for tissue regeneration and repair. PRP has great potential to stimulate cell proliferation and metabolic activity of IVD cells in vitro. Several animal studies have shown that the injection of PRP into degenerated IVDs is effective in restoring structural changes (IVD height) and improving the matrix integrity of degenerated IVDs as evaluated by magnetic resonance imaging (MRI) and histology. The results of this basic research have shown the great possibility that PRP has significant biological effects for tissue repair to counteract IVD degeneration. Clinical studies for evaluating the effects of the injection of PRP into degenerated IVDs for patients with discogenic LBP have been reviewed. Although there was only one double-blind randomized controlled trial, all the studies reported that PRP was safe and effective in reducing back pain. While the clinical evidence of tissue repair of IVDs by PRP treatment is currently lacking, there is a great possibility that the application of PRP has the potential to lead to a feasible intradiscal therapy for the treatment of degenerative disc diseases. Further large-scale studies may be required to confirm the clinical evidence of PRP for the treatment of discogenic LBP.

Correction to: ISSLS PRIZE IN BASIC SCIENCE 2018: Growth differentiation factor-6 attenuated pro-inflammatory molecular changes in the rabbit anular-puncture model and degenerated disc-induced pain generation in the rat xenograft radiculopathy model

The author "Ashish D. Diwan" receives educational consultant fees from Nuvasive Inc.