Protective Effects of Cannabidiol on Lesion-Induced Intervertebral Disc Degeneration

Disc degeneration is a multifactorial process that involves hypoxia, inflammation, neoinnervation, accelerated catabolism, and reduction in water and glycosaminoglycan content. Cannabidiol is the main non-psychotropic component of the Cannabis sativa with protective and anti-inflammatory properties. However, possible therapeutic effects of cannabidiol on intervertebral disc degeneration have not been investigated yet. The present study investigated the effects of cannabidiol intradiscal injection in the coccygeal intervertebral disc degeneration induced by the needle puncture model using magnetic resonance imaging (MRI) and histological analyses. Disc injury was induced in the tail of male Wistar rats via a single needle puncture. The discs selected for injury were punctured percutaneously using a 21-gauge needle. MRI and histological evaluation were employed to assess the results. The effects of intradiscal injection of cannabidiol (30, 60 or 120 nmol) injected immediately after lesion were analyzed acutely (2 days) by MRI. The experimental group that received cannabidiol 120 nmol was resubmitted to MRI examination and then to histological analyses 15 days after lesion/cannabidiol injection. The needle puncture produced a significant disc injury detected both by MRI and histological analyses. Cannabidiol significantly attenuated the effects of disc injury induced by the needle puncture. Considering that cannabidiol presents an extremely safe profile and is currently being used clinically, these results suggest that this compound could be useful in the treatment of intervertebral disc degeneration.     

MRI Assessment of Lumbar Intervertebral Disc Degeneration with Lumbar Degenerative Disease Using the Pfirrmann Grading Systems

Background

To evaluate by MRI intervertebral disc degeneration in patients with lumbar degenerative disease using the Pfirrmann grading system and to determine whether Modic changes correlated with the Pfirrmann grades and modified Pfirrmann grades of disc degeneration.

Methods

The clinical data of 108 surgical patients with lumbar degenerative disease were reviewed and their preoperative MR images were analyzed. Disc degeneration was evaluated using the Pfirrmann grading system. Patients were followed up and low back pain was evaluated using the visual analog scale (VAS) and the effect of back pain on the daily quality of life was assessed using Oswestry disability index (ODI).

Results

Forty-four cases had normal anatomical appearance (Modic type 0) and their Pfirrmann grades were 3.77±0.480 and their modified Pfirrmann grades were of 5.81±1.006. Twenty-seven cases had Modic type I changes and their Pfirrmann grades were 4.79±0.557 and their modified Pfirrmann grades were 7.00±0.832. Thirty-six cases exhibited Modic type II changes and their Pfirrmann grades and modified Pfirrmann grades were 4.11±0.398 and 6.64±0.867, respectively. One case had Modic type III changes. Kruskal-Wallis test revealed significant difference in modified Pfirrmann grade among Modic type 0, I and II changes (P<0.01) but no significant difference between Modic type I and II changes (P>0.05). Binary regression analysis showed that Modic changes correlated most strongly with disc degeneration. Follow up studies indicated that the VAS and ODI scores were markedly improved postoperatively. However, no difference was noted in VAS and ODI scores among patients with different Modic types.

Conclusion

Modic changes correlate with the Pfirrmann and modified Pfirrmann grades of disc degeneration in lumbar degenerative disease. There is no significant correlation between Modic types and surgical outcomes.     

Genetic and Functional Studies of the Intervertebral Disc: A Novel Murine Intervertebral Disc Model

Intervertebral disc (IVD) homeostasis is mediated through a combination of micro-environmental and biomechanical factors, all of which are subject to genetic influences. The aim of this study is to develop and characterize a genetically tractable, ex vivo organ culture model that can be used to further elucidate mechanisms of intervertebral disc disease. Specifically, we demonstrate that IVD disc explants (1) maintain their native phenotype in prolonged culture, (2) are responsive to exogenous stimuli, and (3) that relevant homeostatic regulatory mechanisms can be modulated through ex-vivo genetic recombination. We present a novel technique for isolation of murine IVD explants with demonstration of explant viability (CMFDA/propidium iodide staining), disc anatomy (H&E), maintenance of extracellular matrix (ECM) (Alcian Blue staining), and native expression profile (qRT-PCR) as well as ex vivo genetic recombination (mT/mG reporter mice; AdCre) following 14 days of culture in DMEM media containing 10% fetal bovine serum, 1% L-glutamine, and 1% penicillin/streptomycin. IVD explants maintained their micro-anatomic integrity, ECM proteoglycan content, viability, and gene expression profile consistent with a homeostatic drive in culture. Treatment of genetically engineered explants with cre-expressing adenovirus efficaciously induced ex vivo genetic recombination in a variety of genetically engineered mouse models. Exogenous administration of IL-1ß and TGF-ß3 resulted in predicted catabolic and anabolic responses, respectively. Genetic recombination of TGFBR1^fl/fl explants resulted in constitutively active TGF-ß signaling that matched that of exogenously administered TGF-ß3. Our results illustrate the utility of the murine intervertebral disc explant to investigate mechanisms of intervertebral disc degeneration.     

Annulus Fibrosus Cell Characteristics Are a Potential Source of Intervertebral Disc Pathogenesis

In the end stage of intervertebral disc degeneration, cartilage, bone, endothelial cells, and neurons appear in association with the worsening condition. The origin of the abnormal cells is not clear. This study investigated the properties of progenitor cells in the annulus fibrosus (AF) using one in vitro and two in vivo models. Cultivation of rabbit AF cells with chondrogenic media significantly increased expressions of collagen and aggrecan. Upon exposure to osteogenic conditions, the cultures showed increased mineralization and expression of osteopontin, runx2, and bmp2 genes. Two models were used in the in vivo subcutaneous implantation experiments: 1) rabbit AF tissue in a demineralized bone matrix (DBM) cylinder (DBM/AF), and, 2) rat intact and needle punctured lumbar discs. Bone formation in the AF tissue was detected and hypertrophic chondrocytes and osteoblasts were present 1 month after implantation of the DBM/AF to nude mice. In addition to collagen I and II, immunostaining shows collagen X and osteocalcin expression in DBM/AF specimens 4 months after implantation. Similar changes were detected in the injured discs. Almost the entire needle punctured disc had ossified at 6 months. The results suggest that AF cells have characteristics of progenitor cells and, under appropriate stimuli, are capable of differentiating into chondrocytes and osteoblasts in vitro as well as in vivo. Importantly, these cells may be a target for biological treatment of disc degeneration.     

CT and MRI Determination of Intermuscular Space within Lumbar Paraspinal Muscles at Different Intervertebral Disc Levels

BackgroundRecognition of the intermuscular spaces within lumbar paraspinal muscles is critically important for using the paramedian muscle-splitting approach to the lumbar spine. As such, it is important to determine the intermuscular spaces within the lumbar paraspinal muscles by utilizing modern medical imaging such as computed tomography (CT) and magnetic resonance imaging (MRI).MethodsA total of 30 adult cadavers were studied by sectional anatomic dissection, and 60 patients were examined using CT (16 slices, 3-mm thickness, 3-mm intersection gap, n = 30) and MRI (3.0T, T2-WI, 5-mm thickness, 1-mm intersection gap, n = 30). The distances between the midline and the superficial points of the intermuscular spaces at different intervertebral disc levels were measured.ResultsBased on study of our cadavers, the mean distances from the midline to the intermuscular space between multifidus and longissimus, from intervertebral disc levels L1–L2 to L5–S1, were 0.9, 1.1, 1.7, 3.0, and 3.5 cm, respectively. Compared with the upper levels (L1–L3), the superficial location at the lower level (L4–S1) is more laterally to the midline (P<0.05). The intermuscular space between sacrospinalis and quadratus lumborum, and that between longissimus and iliocostalis did not exist at L4–S1. The intermuscular spaces in patients also varied at different levels of the lumbar spine showing a low discontinuous density in CT and a high signal in MRI. There were no significant differences between the observations in cadavers and those made using CT and MRI.ConclusionThe intermuscular spaces within the paraspinal muscles vary at different intervertebral disc levels. Preoperative CT and MRI can facilitate selection of the muscle-splitting approach to the lumbar spine. This paper demonstrates the efficacy of medical imaging techniques in surgical planning.     

Pathological Alterations and Stress Responses near DBS Electrodes after MRI Scans at 7.0T, 3.0T and 1.5T: An In Vivo Comparative Study

Objective

The purpose of this study was to investigate the pathological alterations and the stress responses around deep brain stimulation (DBS) electrodes after magnetic resonance imaging (MRI) scans at 7.0T, 3.0T and 1.5T.

Materials and Methods

DBS devices were stereotactically implanted into the brains of New Zealand rabbits, targeting the left nucleus ventralis posterior thalami, while on the right side, a puncture passage pointing to the same target was made. MRI scans at 7.0T, 3.0T and 1.5T were performed using transmit/receive head coils. The pathological alterations of the surrounding tissue were evaluated by hematoxylin and eosin staining (H&E staining) and transmission electron microscopy (TEM). The levels of the 70 kDa heat shock protein (HSP-70), Neuronal Nuclei (NeuN) and Caspase-3 were determined by western-blotting and quantitative polymerase chain reaction (QPCR) to assess the stress responses near the DBS electrodes.

Results

H&E staining and TEM showed that the injury around the DBS electrodes was featured by a central puncture passage with gradually weakened injurious alterations. Comparisons of the injury across the groups manifested similar pathological alterations near the DBS electrodes in each group. Moreover, western-blotting and QPCR assay showed that the level of HSP-70 was not elevated by MRI scans (p>0.05), and the levels of NeuN and Caspase-3 were equal in each group, regardless of the field strengths applied (p>0.05).

Conclusions

Based on these findings, it is reasonable to conclude that in this study the MRI scans at multiple levels failed to induce additional tissue injury around the DBS electrodes. These preliminary data furthered our understanding of MRI-related DBS heating and encouraged revisions of the current MRI guidelines for patients with DBS devices.     

Gene expression profile analysis of human intervertebral disc degeneration

In this study, we used microarray analysis to investigate the biogenesis and progression of intervertebral disc degeneration. The gene expression profiles of 37 disc tissue samples obtained from patients with herniated discs and degenerative disc disease collected by the National Cancer Institute Cooperative Tissue Network were analyzed. Differentially expressed genes between more and less degenerated discs were identified by significant analysis of microarray. A total of 555 genes were significantly overexpressed in more degenerated discs with a false discovery rate of < 3%. Functional annotation showed that these genes were significantly associated with membrane-bound vesicles, calcium ion binding and extracellular matrix. Protein-protein interaction analysis showed that these genes, including previously reported genes such as fibronectin, COL2A1 and β-catenin, may play key roles in disc degeneration. Unsupervised clustering indicated that the widely used morphology-based Thompson grading system was only marginally associated with the molecular classification of intervertebral disc degeneration. These findings indicate that detailed, systematic gene analysis may be a useful way of studying the biology of intervertebral disc degeneration.     

Assessment of Lumbar Intervertebral Disc Glycosaminoglycan Content by Gadolinium-Enhanced MRI before and after 21-Days of Head-Down-Tilt Bedrest

During spaceflight, it has been shown that intervertebral discs (IVDs) increase in height, causing elongation of the spine up to several centimeters. Astronauts frequently report dull lower back pain that is most likely of discogenic origin and may result from IVD expansion. It is unknown whether disc volume solely increases by water influx, or if the content of glycosaminoglycans also changes in microgravity. Aim of this pilot study was to investigate effects of the spaceflight analog of bedrest on the glycosaminoglycan content of human lumbar IVDs. Five healthy, non-smoking, male human subjects of European descent were immobilized in 6° head-down-tilt bedrest for 21 days. Subjects remained in bed 24 h a day with at least one shoulder on the mattress. Magnetic Resonance Imaging (MRI) scans were taken according to the delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) protocol before and after bedrest. The outcome measures were T₁ and ΔT₁. Scans were performed before and after administration of the contrast agent Gd-DOTA, and differences between T₁-values of both scans (ΔT₁) were computed. ΔT₁ is the longitudinal relaxation time in the tissue and inversely related to the glycosaminoglycan-content. For data analysis, IVDs L1/2 to L4/5 were semi-automatically segmented. Zones were defined and analyzed separately. Results show a highly significant decrease in ΔT₁ (p<0.001) after bedrest in all IVDs, and in all areas of the IVDs. The ΔT₁-decrease was most prominent in the nucleus pulposus and in L4/5, and was expressed slightly more in the posterior than anterior IVD. Unexpected negative ΔT₁-values were found in Pfirrmann-grade 2-discs after bedrest. Significantly lower T₁ before contrast agent application was found after bedrest compared to before bedrest. According to the dGEMRIC-literature, the decrease in ΔT₁ may be interpreted as an increase in glycosaminoglycans in healthy IVDs during bedrest. This interpretation seems contradictory to previous findings in IVD unloading.     

Magnetic Resonance Imaging Interpretation in Patients with Sciatica Who Are Potential Candidates for Lumbar Disc Surgery

Background

Magnetic Resonance Imaging (MRI) is considered the mainstay imaging investigation in patients suspected of lumbar disc herniations. Both imaging and clinical findings determine the final decision of surgery. The objective of this study was to assess MRI observer variation in patients with sciatica who are potential candidates for lumbar disc surgery.

Methods

Patients for this study were potential candidates (n = 395) for lumbar disc surgery who underwent MRI to assess eligibility for a randomized trial. Two neuroradiologists and one neurosurgeon independently evaluated all MRIs. A four point scale was used for both probability of disc herniation and root compression, ranging from definitely present to definitely absent. Multiple characteristics of the degenerated disc herniation were scored. For inter-agreement analysis absolute agreements and kappa coefficients were used. Kappa coefficients were categorized as poor (<0.00), slight (0.00–0.20), fair (0.21–0.40), moderate (0.41–0.60), substantial (0.61–0.80) and excellent (0.81–1.00) agreement.

Results

Excellent agreement was found on the affected disc level (kappa range 0.81–0.86) and the nerve root that most likely caused the sciatic symptoms (kappa range 0.86–0.89). Interobserver agreement was moderate to substantial for the probability of disc herniation (kappa range 0.57–0.77) and the probability of nerve root compression (kappa range 0.42–0.69). Absolute pairwise agreement among the readers ranged from 90–94% regarding the question whether the probability of disc herniation on MRI was above or below 50%. Generally, moderate agreement was observed regarding the characteristics of the symptomatic disc level and of the herniated disc.

Conclusion

The observer variation of MRI interpretation in potential candidates for lumbar disc surgery is satisfactory regarding characteristics most important in decision for surgery. However, there is considerable variation between observers in specific characteristics of the symptomatic disc level and herniated disc.     

Imbalanced Protein Expression Patterns of Anabolic,Catabolic, Anti-Catabolic and Inflammatory Cytokines in Degenerative Cervical Disc Cells: New Indications for Gene Therapeutic Treatments of Cervical Disc Diseases

Degenerative disc disease (DDD) of the cervical spine is common after middle age and can cause loss of disc height with painful nerve impingement, bone and joint inflammation. Despite the clinical importance of these problems, in current publications the pathology of cervical disc degeneration has been studied merely from a morphologic view point using magnetic resonance imaging (MRI), without addressing the issue of biological treatment approaches. So far a wide range of endogenously expressed bioactive factors in degenerative cervical disc cells has not yet been investigated, despite its importance for gene therapeutic approaches. Although degenerative lumbar disc cells have been targeted by different biological treatment approaches, the quantities of disc cells and the concentrations of gene therapeutic factors used in animal models differ extremely. These indicate lack of experimentally acquired data regarding disc cell proliferation and levels of target proteins. Therefore, we analysed proliferation and endogenous expression levels of anabolic, catabolic, ant-catabolic, inflammatory cytokines and matrix proteins of degenerative cervical disc cells in three-dimensional cultures. Preoperative MRI grading of cervical discs was used, then grade III and IV nucleus pulposus (NP) tissues were isolated from 15 patients, operated due to cervical disc herniation. NP cells were cultured for four weeks with low-glucose in collagen I scaffold. Their proliferation rates were analysed using 3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide. Their protein expression levels of 28 therapeutic targets were analysed using enzyme-linked immunosorbent assay. During progressive grades of degeneration NP cell proliferation rates were similar. Significantly decreased aggrecan and collagen II expressions (P<0.0001) were accompanied by accumulations of selective catabolic and inflammatory cytokines (disintegrin and metalloproteinase with thrombospondin motifs 4 and 5, matrix metalloproteinase 3, interleukin-1β, interleukin-1 receptor) combined with low expression of anti-catabolic factor (metalloproteinase inhibitor 3) (P<0.0001). This study might contribute to inhibit inflammatory catabolism of cervical discs.     

Chondroadherin Fragmentation Mediated by the Protease HTRA1 Distinguishes Human Intervertebral Disc Degeneration from Normal Aging

Chondroadherin, a member of the leucine-rich repeat family, has previously been demonstrated to be fragmented in some juveniles with idiopathic scoliosis. This observation led us to investigate adults with disc degeneration. Immunoblotting analysis demonstrated that non-degenerate discs from three different age groups show no chondroadherin fragmentation. Furthermore, the chondroadherin fragments in adult degenerate disc and the juvenile scoliotic disc were compared via immunoblot analysis and appeared to have a similar size. We then investigated whether or not chondroadherin fragmentation increases with the severity of disc degeneration. Three different samples with different severities were chosen from the same disc, and chondroadherin fragmentation was found to be more abundant with increasing severity of degeneration. This observation led us to the creation of a neoepitope antibody to the cleavage site observed. We then observed that the cleavage site in adult degenerate discs and juvenile scoliotic discs was identical as confirmed by the neoepitope antibody. Consequently, investigation of the protease capable of cleaving chondroadherin at this site was necessary. In vitro digests of disc tissue demonstrated that ADAMTS-4 and -5; cathepsins K, B, and L; and MMP-3, -7, -12, and -13 were incapable of cleavage of chondroadherin at this site and that HTRA1 was indeed the only protease capable. Furthermore, increased protein levels of the processed form of HTRA1 were demonstrated in degenerate disc tissues via immunoblotting. The results suggest that chondroadherin fragmentation can be used as a biomarker to distinguish the processes of disc degeneration from normal aging.     

Effect of autologous platelet-rich plasma-releasate on intervertebral disc degeneration in the rabbit anular puncture model: a preclinical study

Introduction

Platelet-rich plasma (PRP) is a fraction of plasma in which several growth factors are concentrated at high levels. The active soluble releasate isolated following platelet activation of PRP (PRP-releasate) has been demonstrated to stimulate the metabolism of IVD cells in vitro. The in vivo effect of PRP-releasate on degenerated IVD remains unknown. The purpose of this study was to determine the reparative effects of autologous PRP-releasate on degenerated intervertebral discs (IVDs).

Methods

To induce disc degeneration, New Zealand white rabbits (n = 12) received anular puncture in two noncontiguous discs. Autologous PRP and PPP (platelet-poor plasma) were isolated from fresh blood using two centrifugation techniques. Four weeks after the initial puncture, releasate isolated from clotted PPP or PRP (PPP- or PRP-releasate), or phosphate-buffered saline (PBS; control) was injected into the punctured discs. Disc height, magnetic resonance imaging (MRI) T2-mapping and histology were assessed.

Results

Anular puncture produced a consistent disc narrowing within four weeks. PRP-releasate induced a statistically significant restoration of disc height (PRP vs. PPP and PBS, P<0.05). In T2-quantification, the mean T2-values of the nucleus pulposus (NP) and anulus fibrosus (AF) of the discs were not significantly different among the three treatment groups. Histologically, the number of chondrocyte-like cells was significantly higher in the discs injected with PRP-releasate compared to that with PBS.

Conclusions

The administration of active PRP-releasate induced a reparative effect on rabbit degenerated IVDs. The results of this study suggest that the use of autologous PRP-releasate is safe and can lead to a clinical application for IVD degeneration.

     

退行性腰椎滑脱临近节段椎间盘退变和关节突关节角度相关研究

目的:探讨退行性腰椎滑脱(DLS)临近节段椎间盘退变程度和关节突关节角度之间的关系。方法:选取我院2012年6月至2016年6月收治的120例DLS患者作为DLS组,另外选取来我院接受体检的健康者120例作为对照组,选择CT进行关节突关节角和腰椎滑脱度的测量,使用MRI的T2像对椎间盘进行Pfirrmann退变分级。结果:DLS组的各节段关节突关节角度均小于对照组(P0.05);DLS组不同滑脱程度的L2/3、L3/4、L5/S1节段关节突关节角度的比较,差异无统计学意义(P0.05);DLS组L2/3、L3/4、L5/S1节段不同椎间盘退变等级间的滑脱程度无显著性差异(P0.05)。L2/3和L3/4节段不同椎间盘退变程度间关节突关节角度差无显著性差异(P0.05),L5/S1节段不同椎间盘退变程度间关节突关节角度差有统计学差异(P0.05)。结论:退行性腰椎滑脱临近节段关节突关节角度明显小于正常人,且临近节段关节突关节的角度并未随着腰椎滑脱程度的加重而改变,退行性腰椎滑脱患者滑脱临近节段椎间盘退变与关节突关节的矢状化程度无关,但L5/S1关节突关节角度不对称性会影响到同节段椎间盘退变程度。     

Disc degeneration implies low back pain

Background

Low back pain exerts a tremendous burden on individual patients and society due to its prevalence and ability to cause long-term disability. Contemporary treatment and prevention efforts are stymied by the absence of a confirmed cause for the majority of low back pain patients.

Methods

A system dynamics approach is used to build a physiologically-based model investigating the relationship between disc degeneration and low back pain. The model’s predictions are evaluated under two different types of study designs and compared with established observations on low back pain.

Results

A three-compartment model (no disc degeneration, disc degeneration with pain remission, disc degeneration with pain recurrence) accurately predicts the age-specific prevalence observed in one of the largest population-based surveys (R ²?=?0.998). The estimated transition age at which intervertebral discs lose the growth potential and begin degenerating is 13.3 years. The estimated disc degeneration rate is 0.0344/year. Without any additional change being made to parameter’s values, the model also fully accounts for the age-specific prevalence of disc degeneration detected with a lumbar MRI among asymptomatic individuals (R ²?=?0.978).

Conclusions

Dual testing of the proposed mechanistic model with two independent data sources (one with lumbar MRI and the other without) confirm that disc degeneration is the driving force behind and cause of age dependence in low back pain. Observed complexity of low back pain epidemiology arises from the slow dynamics of disc degeneration coupled with the fast dynamics of disease recurrence.

     

Glaucomatous-Type Optic Discs in High Myopia

Purpose

To assess the prevalence of glaucoma in patients with high myopia defined as myopic refractive error of >-8 diopters or axial length ≥26.5 mm.

Methods

The hospital-based observational study included 172 patients (336 eyes) with a mean age of 61.9±12.3 years and mean axial length of 30.1±2.3 mm (range: 24.7–39.1mm). Glaucomatous-type optic discs were defined by glaucomatous optic disc appearance. Glaucoma was defined by glaucomatous optic disc appearance and glaucomatous Goldmann visual field defects not corresponding with myopic macular changes.

Results

Larger disc area (mean: 3.18±1.94 mm²) was associated with longer axial length (P<0.001; standardized correlation coefficient: 0.45). Glaucoma was detected in 94 (28%; 95% Confidence intervals: 23%, 33%) eyes. In multivariate analysis, glaucoma prevalence was 3.2 times higher (P<0.001) in megalodiscs (>3.79 mm²) than in normal-sized discs or small discs (<1.51 mm²) after adjusting for older age. Axial length was not significantly (P = 0.38) associated with glaucoma prevalence in that model. Glaucoma prevalence increased by a factor of 1.39 for each increase in optic disc area by one mm². Again, axial length was not significantly (P = 0.38) associated with glaucoma prevalence when added to this multivariate model.

Conclusion

Within highly myopic individuals, glaucoma prevalence increased with larger optic disc size beyond a disc area of 3.8 mm². Highly myopic megalodiscs as compared to normal sized discs or small discs had a 3.2 times higher risk for glaucomatous optic nerve neuropathy. The increased glaucoma prevalence in axial high myopia was primarily associated with axial myopia associated disc enlargement and not with axial elongation itself.     

Intervertebral disc disease in Dachshunds radiographically screened for intervertebral disc calcifications

Background

Intervertebral disc disease (IDD) is a very common neurological disease, Dachshunds being the breed most often affected. In this breed, IDD has a hereditary background and is associated with intervertebral disc calcification (IDC), an indicator of severe intervertebral disc degeneration. In Finland, spinal radiography is used, when screening for IDC before breeding Dachshunds. We evaluated the association between IDC and IDD in Finnish Dachshunds radiographically screened for IDC.A questionnaire was sent to owners of 193 radiographically screened Dachshunds aged at least ten years. Clinical signs indicative of IDD were compared with IDC grade (grade 0?=?no calcifications, grade 1?=?1 – 2 calcifications, grade 2?=?3 – 4 calcifications and grade 3?=?5 or more calcifications) and with age at the time of the radiographic examination. The diagnosis of IDD was confirmed by a veterinarian.

Results

IDD was common in the study population with 31% of dogs being affected. IDD and IDC were clearly connected (P?<?0.001); IDD was rare in dogs with no calcifications (grade 0) and common in dogs with severe IDC (grade 3). The IDC grade was strongly positively associated with frequency of back pain periods (P?<?0.001), and dogs with IDC grade 3 had frequent periods of pain. Reluctance to jump onto a sofa had a strong positive association with back pain. No association existed between age of the dog at the time of the radiographic examination and clinical signs indicative of IDD.

Conclusions

Radiographically detected IDC and IDD are common in Finnish Dachshunds and are strongly associated with one another. Spinal radiography is an appropriate screening tool for breeders attempting to diminish IDC and IDD in Dachshunds. A breeding program that screens dogs and selects against IDC can be expected to reduce the occurrence of IDD in future. Twenty-four to 48 months of age is a suitable age for screening.

     

Optic Disc - Fovea Distance,Axial Length and Parapapillary Zones. The Beijing Eye Study 2011

Purpose

To measure the distance between the optic disc center and the fovea (DFD) and to assess its associations.

Methods

The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals aged 50+ years. The DFD was measured on fundus photographs.

Results

Readable fundus photographs were available for 2836 (81.8%) individuals. Mean DFD was 4.76 ± 0.34mm (median: 4.74 mm; range: 3.76–6.53mm). In multivariate analysis, longer DFD was associated with longer axial length (P<0.001; standardized correlation coefficient beta: 0.62), higher prevalence of axially high myopia (P<0.001; beta:0.06), shallower anterior chamber depth (P<0.001; beta:-0.18), thinner lens thickness (P = 0.004; beta: -0.06), smaller optic disc-fovea angle (P = 0.02; beta: -0.04), larger parapapillary alpha zone (P = 0.008; beta: 0.05), larger parapapillary beta/gamma zone (P<0.001; beta: 0.11), larger optic disc area (P<0.001; beta: 0.08), lower degree of cortical cataract (P = 0.002; beta: -0.08), and lower prevalence of age-related macular degeneration (P = 0.001; beta: -0.06). Bruch´s membrane opening-fovea distance (DFD minus disc radius minus parapapillary beta/gamma zone width) in non-glaucomatous eyes was not significantly (P = 0.60) related with axial length in emmetropic or axially myopic eyes (axial length ≥23.5 mm), while it increased significantly (P<0.001; r: 0.32) with longer axial length in eyes with an axial length of <23.5mm. Ratio of mean DFD to disc diameter was 2.65 ± 0.30. If the ratio of disc-fovea distance to disc diameter was considered constant and if the individual disc diameter was calculated as the individual disc-fovea distance divided by the constant factor of 2.65, the resulting calculated disc diameter differed from the directly measured disc diameter by 0.16 ±0.13 mm (median: 0.13 mm, range: 0.00–0.89 mm) or 8.9 ± 7.3% (median: 7.4%; range: 0.00–70%) of the measured disc diameter.

Conclusions

DFD (mean: 4.76mm) increases with longer axial length, larger parapapillary alpha zone and parapapillary beta/gamma zone, and larger disc area. The axial elongation associated increase in DFD was due to an enlargement of parapapillary beta/gamma zone while the Bruch’s membrane opening-fovea distance did not enlarge with longer axial length. This finding may be of interest for the process of emmetropization and myopization. Due to its variability, the disc-fovea distance has only limited clinical value as a relative size unit for structures at the posterior pole.     

Global Identification of Genes Related to Nutrient Deficiency in Intervertebral Disc Cells in an Experimental Nutrient Deprivation Model

Background

Intervertebral disc degeneration is a significant cause of degenerative spinal diseases. Nucleus pulposus (NP) cells reportedly fail to survive in large degenerated discs with limited nutrient availability. Therefore, understanding the regulatory mechanism of the molecular response of NP cells to nutrient deprivation may reveal a new strategy to treat disc degeneration. This study aimed to identify genes related to nutrient deprivation in NP cells on a global scale in an experimental nutrient deprivation model.

Methodology/Principal Findings

Rat NP cells were subjected to serum starvation. Global gene expression was profiled by microarray analysis. Confirmation of the selected genes was obtained by real-time polymerase chain reaction array analysis. Western blotting was used to confirm the expression of selected genes. Functional interactions between p21^Cip1 and caspase 3 were examined. Finally, flow cytometric analyses of NP cells were performed. Microarray analysis revealed 2922 differentially expressed probe sets with ≥1.5-fold changes in expression. Serum starvation of NP cells significantly affected the expression of several genes involved in DNA damage checkpoints of the cell cycle, including Atm, Brca1, Cdc25, Gadd45, Hus1, Ppm1D, Rad 9, Tp53, and Cyclin D1. Both p27^Kip1 and p53 protein expression was upregulated in serum-starved cells. p21^Cip1 expression remained in NP cells transfected with short interfering RNA targeting caspase 3 (caspase 3 siRNA). Both G1 arrest and apoptosis induced by serum starvation were inhibited in cells transfected with caspase 3 siRNA.

Conclusions/Significance

Nutrient deprivation in NP cells results in the activation of a signaling response including DNA damage checkpoint genes regulating the cell cycle. These results provide novel possibilities to improve the success of intervertebral disc regenerative techniques.     

Effects of pulsed electromagnetic field on intervertebral disc cell apoptosis in rats

Despite numerous studies on pulsed electromagnetic field (PEMF) application, its effects of PEMF on intervertebral disc (IVD) have not yet been investigated in vivo. Accordingly, the effects of PEMF upon IVD in rats were evaluated through molecular surveys. Rats were divided into six groups: Group I and II were exposed to low and high frequency of PEMF (LF and HF, respectively). Group III and IV underwent induced disc degeneration and were exposed to low and high frequency of PEMF (LF/IDD and HF/IDD, respectively). Group V underwent induced disc degeneration (IDD), and group VI was control. The values of caspase 3, Bax, Bcl-2 and β-actin band density, as cell apoptotic markers, were obtained from band densitometry. Our results showed that the value of cleaved caspase-3 of cells and Bax/Bcl-2 ratio in IDD group increased significantly compared to the control group (p?p?相似文献