The influence of diabetes mellitus on lumbar intervertebral disk herniation

Understanding the etiopathogenesis of lumbar intervertebral disc herniation: From clinical evidence to basic scientific research

Lumbar intervertebral disc herniation, as a leading cause of low back pain, productivity loss, and disability, is a common musculoskeletal disorder that results in significant socioeconomic burdens. Despite extensive clinical and basic scientific research efforts, herniation etiopathogenesis, particularly its initiation and progression, is not well understood. Understanding herniation etiopathogenesis is essential for developing effective preventive measures and therapeutic interventions. Thus, this review seeks to provide a thorough overview of the advances in herniation-oriented research, with a discussion on ongoing challenges and potential future directions for clinical, translational, and basic scientific investigations to facilitate innovative interdisciplinary research aimed at understanding herniation etiopathogenesis. Specifically, risk factors for herniation are identified and summarized, including familial predisposition, obesity, diabetes mellitus, smoking tobacco, selected cardiovascular diseases, disc degeneration, and occupational risks. Basic scientific experimental and computational research that aims to understand the link between excessive mechanical load, catabolic tissue remodeling due to inflammation or insufficient nutrient supply, and herniation, are also reviewed. Potential future directions to address the current challenges in herniation-oriented research are explored by combining known progressive development in existing research techniques with ongoing technological advances. More research on the relationship between occupational risk factors and herniation, as well as the relationship between degeneration and herniation, is needed to develop preventive measures for working-age individuals. Notably, researchers should explore using or modifying existing degeneration animal models to study herniation etiopathogenesis, as such models may allow for a better understanding of how to prevent mild-to-moderately degenerated discs from herniating.

Strong association of lumbar disk herniation with diabetes mellitus: a 12-year nationwide retrospective cohort study

Background

Despite reports on the association between diabetes mellitus (DM) and lumbar disk herniation (LDH), large-scale, nationwide studies exploring this relationship are lacking. We aimed to examine the profiles of DM in individuals with LDH and explore the potential mechanisms underlying the development of these disorders.

Methods

This retrospective, population-based study was conducted between 2008 and 2019 using data from the National Health Insurance (NHI) research database in Taiwan. The primary outcome was the date of initial LDH diagnosis, death, withdrawal from the NHI program, or end of the study period.

Results

In total, 2,662,930 individuals with and 16,922,546 individuals without DM were included in this study; 719,068 matched pairs were established following propensity score matching (1:1 ratio) for sex, age, comorbidities, smoking, alcohol consumption, antihyperglycemic medications, and index year. The adjusted risk for developing LDH was 2.33-fold (95% confidence interval: 2.29-2.37; P<0.001), age-stratified analysis revealed a significantly greater risk of LDH in every age group, and both males and females were approximately twice as likely to develop LDH in the DM compared with non-DM cohort. Individuals with DM and comorbidities had a significantly higher risk of developing LDH than those without, and the serial models yielded consistent results. Treatment with metformin, sulfonylureas, meglitinides, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, or alpha-glucosidase inhibitors was associated with a more than 4-fold increased risk of LDH in the DM cohort. DM was strongly associated with the long-term development of LDH; over the 12-year follow-up period, the cumulative risk of LDH was significantly higher in patients with than without DM (log-rank P<0.001).

Conclusion

DM is associated with an increased risk of LDH, and advanced DM may indicate a higher risk of LDH.

Patient-related risk factors and lifestyle factors for lumbar degenerative disc disease: a systematic review

OBJECTIVE

Back pain is a very widespread disease pattern and is one of the most frequent causes for consultation of a physician in general. In most cases, discogenic changes are the pathomorphological correlate of back pain. Numerous risk factors have been identified for these degenerative changes, but the influence and significance of the risk factors remain unclear, which was the aim of this systematic review.

METHODS

A systematic literature search of the commonly used Pubmed database was performed using specific MESH terms. Further selection of the included studies was performed according to the PRISMA scheme, taking into account scientific merit as well as the relation to the research question.

RESULTS

A total of 111 studies out of 1035 found were finally included in the literature search. 134 risk factors for disc degeneration and disc herniation were identified. These were divided into (1) patient-specific risk factors (n░=░34), (2) radiological risk factors (n░=░31), (3) lifestyle risk factors (n░=░6), (4) workplace-related risk factors (n░=░12), (5) genetic risk factors (n░=░50), and (6) other risk factors (n░=░1). Non-adjustable risk factors were age >50 years (OR 1.7/year), female gender (OR 1.41), family disposition (OR 4.0), comorbidities like atherosclerosis (OR 2.24), arthritic changes in other joints (OR 3.1) and history of injuries of the back (OR 3.1). Adjustable factors were elevated BMI (OR 2.77), comorbidities like hypertension (OR 1.25), dyslipidemia (OR 1.26) and diabetes mellitus (OR 6.8), as well as lifestyle habits like smoking (OR 3.8).

DISCUSSION

In summary, intervertebral disc degenerations and herniations represent multifactorial events whose risk factors can be partly influenced and partly not influenced. This systematic review highlights the current state of knowledge as a basis for creating patient-specific algorithms to calculate risk for the development or progression of degenerative disc changes and disc herniations.

Cellular Senescence in Intervertebral Disc Aging and Degeneration: Molecular Mechanisms and Potential Therapeutic Opportunities

Closely associated with aging and age-related disorders, cellular senescence (CS) is the inability of cells to proliferate due to accumulated unrepaired cellular damage and irreversible cell cycle arrest. Senescent cells are characterized by their senescence-associated secretory phenotype that overproduces inflammatory and catabolic factors that hamper normal tissue homeostasis. Chronic accumulation of senescent cells is thought to be associated with intervertebral disc degeneration (IDD) in an aging population. This IDD is one of the largest age-dependent chronic disorders, often associated with neurological dysfunctions such as, low back pain, radiculopathy, and myelopathy. Senescent cells (SnCs) increase in number in the aged, degenerated discs, and have a causative role in driving age-related IDD. This review summarizes current evidence supporting the role of CS on onset and progression of age-related IDD. The discussion includes molecular pathways involved in CS such as p53-p21CIP1, p16INK4a, NF-κB, and MAPK, and the potential therapeutic value of targeting these pathways. We propose several mechanisms of CS in IDD including mechanical stress, oxidative stress, genotoxic stress, nutritional deprivation, and inflammatory stress. There are still large knowledge gaps in disc CS research, an understanding of which will provide opportunities to develop therapeutic interventions to treat age-related IDD.

Inhibitory Effect of Insulin Treatment on Apoptosis of Intervertebral Disc Cells in a Streptozotocin-Induced Diabetic Rat Model

STUDY DESIGN

Experimental study using a streptozotocin (STZ)-induced diabetic rat model.

PURPOSE

This study aims to investigate whether insulin treatment could attenuate disc cell apoptosis and matrix degradation in a STZ-induced diabetic rat model.

OVERVIEW OF LITERATURE

Diabetes is a significant risk factor for disc degeneration due to excessive apoptosis of disc cells and matrix degradation. However, no studies were noted to demonstrate the inhibitory effect of insulin treatment on the apoptosis of disc cells and matrix degradation in diabetic patients.

METHODS

Rats were allocated randomly into one of three groups: control, STZ, and STZ-insulin. Diabetes was induced by a single intraperitoneal injection of STZ (65 mg/kg) in the STZ and STZ-insulin groups. The blood glucose level was consistently above 400 mg/ dL in the STZ and STZ-insulin groups 2 weeks after STZ injection. After 2 weeks of STZ injection, the STZ-insulin group was administered insulin treatment (1.5 unit/100 g) daily for up to 4 weeks. Blood glucose of the STZ-insulin rats significantly decreased to normal levels 4 weeks after insulin treatment. The rats were sacrificed 6 weeks after STZ injection, and disc cells and tissues were harvested to investigate the expression of apoptosis markers and matrix metalloproteinases (MMPs).

RESULTS

Fas and caspase-8, -9, and -3 expressions were significantly increased in the STZ group, along with increased expressions of MMP-2 and -3. On the contrary, insulin treatment significantly decreased the expressions of Fas, caspase-8, -9, and -3 as well as MMP-2 and -3 in the STZ-insulin group.

CONCLUSIONS

The results of the current study demonstrated that insulin treatment attenuates excessive apoptosis of disc cells and matrix degradation in the diabetic rat model. Accordingly, strict blood glucose control should be recommended to prevent disc degeneration in diabetic patients.

A Machine Learning Model to Predict Length of Stay and Mortality among Diabetes and Hypertension Inpatients

Background and Objectives: Taiwan is among the nations with the highest rates of Type 2 Diabetes Mellitus (T2DM) and Hypertension (HTN). As more cases are reported each year, there is a rise in hospital admissions for people seeking medical attention. This creates a burden on hospitals and affects the overall management and administration of the hospitals. Hence, this study aimed to develop a machine learning (ML) model to predict the Length of Stay (LoS) and mortality among T2DM and HTN inpatients. Materials and Methods: Using Taiwan's National Health Insurance Research Database (NHIRD), this cohort study consisted of 58,618 patients, where 25,868 had T2DM, 32,750 had HTN, and 6419 had both T2DM and HTN. We analyzed the data with different machine learning models for the prediction of LoS and mortality. The evaluation was done by plotting descriptive statistical graphs, feature importance, precision-recall curve, accuracy plots, and AUC. The training and testing data were set at a ratio of 8:2 before applying ML algorithms. Results: XGBoost showed the best performance in predicting LoS (R2 0.633; RMSE 0.386; MAE 0.123), and RF resulted in a slightly lower performance (R2 0.591; RMSE 0.401; MAE 0.027). Logistic Regression (LoR) performed the best in predicting mortality (CV Score 0.9779; Test Score 0.9728; Precision 0.9432; Recall 0.9786; AUC 0.97 and AUPR 0.93), closely followed by Ridge Classifier (CV Score 0.9736; Test Score 0.9692; Precision 0.9312; Recall 0.9463; AUC 0.94 and AUPR 0.89). Conclusions: We developed a robust prediction model for LoS and mortality of T2DM and HTN inpatients. Linear Regression showed the best performance for LoS, and Logistic Regression performed the best in predicting mortality. The results showed that ML algorithms can not only help healthcare professionals in data-driven decision-making but can also facilitate early intervention and resource planning.

In vitro and in vivo effects of hyperglycemia and diabetes mellitus on nucleus pulposus cell senescence

Diabetes mellitus contributes to intervertebral disc degeneration. Nucleus pulposus cell senescence plays an important role in intervertebral disc degeneration. However, the effects of hyperglycemia on human nucleus pulposus cells and the underlying process remains poorly understood. In the current study, we evaluated the effects of high glucose levels on human nucleus pulposus cell senescence in vitro and the effects of hyperglycemia on rat nucleus pulposus aging in vivo. Human nucleus pulposus cells were cultured in high-glucose medium (200 mM glucose) for 48 h. Senescence-associated β-galactosidase staining, western blot analysis, and enzyme-linked immunosorbent assays were performed to evaluate human nucleus pulposus cell senescence. Flow cytometry and enzyme-linked immunosorbent assays were used to evaluate reactive oxygen species and advanced glycation end-product levels. Transcriptome sequencing followed by bioinformatics analysis was used to understand the abnormal biological processes of nucleus pulposus cells cultured in high-glucose medium. Diabetes mellitus rat models were established and histopathological and immunohistochemical analysis was conducted to examine nucleus pulposus tissue senescence in vivo. Exposure to a high glucose concentration promoted human nucleus pulposus cell senescence and increased the senescence-related secretion phenotype in human nucleus pulposus cells in vitro and in rat nucleus pulposus tissue in vivo. Bioinformatics analysis showed that hub genes were involved in nucleus pulposus cell cycle activities and cell senescence. The results suggest that appropriate blood glucose control may be key to preventing intervertebral disc degeneration in diabetic patients.

Type 2 diabetes mellitus, physical activity, and neuromusculoskeletal complications

Objectives

The objectives of the study were to investigate the neuromusculoskeletal complications of Type 2 diabetes mellitus (T2DM) and their associated factors, including the level of physical activity (PA) and clinicodemographic characteristics.

Materials and Methods

In this cross-sectional analysis, we included 370 participants diagnosed with T2DM for no <1 year who satisfied the inclusion and exclusion criteria. Demographic and clinical characteristics were noted and a thorough clinical examination was performed on all the participants. International PA Questionnaire-Short Form was used to evaluate the level of PA of the participants. The continuous data is presented as mean ± SD and the categorical data is presented as the number of participants (n) and percentage (%). A logistic regression model was used to investigate the predictors for the prevalence of the complications.

Results

The mean duration of T2DM was 7.32 ± 5.53 years and the mean hemoglobin A1C (HbA1c) level (%) was 8.16±1.67. A majority of the participants were having uncontrolled diabetes with an HbA1c level ≥7.5% (n = 190; 51.35%). The level of PA was low in a substantial proportion of the participants (n = 276; 74.59%). A total of 162 (43.78%) participants were diagnosed with neuromusculoskeletal complications. Low back pain was the most common complication and degenerative disk disease was the most common diagnosis overall. Longer duration of diabetes, poor glycemic control, and low PA were associated with the prevalence of neuromusculoskeletal complications (P < 0.05).

Conclusion

Neuromusculoskeletal complications of T2DM are common and can result in significant disability in this population. Low PA is very common among T2DM patients and an important contributor to the development of complications. Health-care providers should consider PA an integral component of the management protocol for T2DM patients.

Systemic Risk Factors for Adult Spinal Deformity (ASD): A Retrospective Analysis of 48 Patients

Introduction: Adult spinal deformity (ASD) results in significant patient morbidity and burden to quality of life. The degree to which systemic risk factors and comorbidities that contribute to ASD affect specific spinopelvic parameters is not well-documented. We determine the extent to which preoperative risk factors may contribute to spinopelvic parameters associated with ASD.

Methods: Retrospective single-center study of 48 patients with ASD. Analysis of variance (ANOVA) linear regression analysis was performed to evaluate correlation between systemic comorbidities (obesity, arterial hypertension (HTN), hyperlipidemia (HLD), cardiomyopathy, diabetes mellitus (DM), chronic obstructive pulmonary disease (COPD), and asthma) and the following radiographic parameters: pelvic incidence (PI), lumbar lordosis (LL), C7 sagittal vertical axis (C7SVA), and the T10-L2 sagittal cobb angle.

Results: A total of 48 patients were included with mean C7SVA of 79.6 mm (SD: 63, range: 43-254), mean LL of 32.9° (SD: 15.9, range: -14 to 78), T10-L2 sagittal cobb angle of 3° (SD: 12.7, range: -24 to 30), and PI was 49° (SD: 10.7, range: 21 to 77). Only DM correlated with sagittal imbalance with high C7SVA and PI-LL mismatch. The beta coefficient for DM and preoperative C7SVA was 0.49, t=3.16, p=0.003, preoperative PI-LL mismatch standardized beta coefficient was -0.4, t=-2.38, p=0.022, and preoperative T10-L2 sagittal cobb standard beta coefficient was -0.07, t=-0.46, p=0.645. No significant correlations were found for asthma, COPD, HTN, HLD, or cardiomyopathy.

Conclusions: Diagnosis of DM was found to correlate with pathologic C7SVA and significant PI-LL mismatch associated with ASD. HTN, HLD, cardiomyopathy, obesity, and pulmonary disease did not correlate with radiographic findings of sagittal imbalance.

The degenerative impact of hyperglycemia on the structure and mechanics of developing murine intervertebral discs

Introduction

Diabetes has long been implicated as a major risk factor for intervertebral disc (IVD) degeneration, interfering with molecular signaling and matrix biochemistry, which ultimately aggravates the progression of the disease. Glucose content has been previously shown to influence structural and compositional changes in engineered discs in vitro, impeding fiber formation and mechanical stability.

Methods

In this study, we investigated the impact of diabetic hyperglycemia on young IVDs by assessing biochemical composition, collagen fiber architecture, and mechanical behavior of discs harvested from 3‐ to 4‐month‐old db/db mouse caudal spines.

Results

We found that discs taken from diabetic mice with elevated blood glucose levels demonstrated an increase in total glycosaminoglycan and collagen content, but comparable advanced glycation end products (AGE) levels to wild‐type discs. Diabetic discs also contained ill‐defined boundaries between the nucleus pulposus and annulus fibrosus, with the latter showing a disorganized and unaligned collagen fiber network at this same boundary.

Conclusions

These compositional and structural changes had a detrimental effect on function, as the diabetic discs were twice as stiff as their wild‐type counterparts and demonstrated a significant resistance to deformation. These results indicate that diabetes may predispose the young disc to DDD later in life by altering patterns of extracellular matrix deposition, fiber formation, and motion segment mechanics independently of AGE accumulation.

Diabetes Mellitus-A Risk Factor for the Development of Lumbar Disc Degeneration: A Retrospective Study of an Indian Population

STUDY DESIGN

A retrospective study.

OBJECTIVES

To determine the association between type-2 diabetes mellitus (T2DM) and the severity of lumbar disc degeneration disease (LDDD).

METHODS

We included 199 patients with low back pain (LBP) who visited our hospital from 2016 to 2018. All patients were divided into 3 groups as per inclusion criteria. Group A, patients without DM (n = 75); group B, patients with controlled DM (n = 72); and group C, patients with uncontrolled DM (n = 52). The patients were further subdivided into group B1, DM duration ≤10 years (n = 38); group B2, DM duration >10 years (n = 34); group C1 DM duration ≤10 years (n = 28); and group C2, DM duration >10 years (n = 24). Sex, age, body mass index, occupation, smoking history, alcohol use, and duration of T2DM were recorded. The severity of LDDD was evaluated using the 5-level Pfirrmann grading system. Operated patients' disc materials were sent for histological examination.

RESULTS

Demographic data showed no difference among groups (P > 0.5), except age. Patients with DM showed more severe disc degeneration compared with patients without DM. The average Pfirrmann scores between groups A and B1 had no difference; groups B2, C1, and C2 showed higher average Pfirrmann scores than group A (P < 0.05). Groups B2 and C2 showed higher average Pfirrmann scores than groups B1 and C1 (P < 0.05). Groups C1 and C2 showed higher average Pfirrmann scores than groups B1 and B2 (P < 0.05). The severity of LDDD was significantly related to DM duration in both groups B and C (P < 0.05). DM groups showed increased disc apoptosis and matrix aggrecan fragmentation, disc glycosaminoglycan content and histological analysis were significantly different; the results are similar to Pfirrmann score results.

CONCLUSIONS

DM duration >10 years and uncontrolled DM were risk factors for LDDD.

Endoplasmic reticulum stress associates with the development of intervertebral disc degeneration

Endoplasmic reticulum (ER) is an important player in various intracellular signaling pathways that regulate cellular functions in many diseases. Intervertebral disc degeneration (IDD), an age-related degenerative disease, is one of the main clinical causes of low back pain. Although the pathological development of IDD is far from being fully elucidated, many studies have been shown that ER stress (ERS) is involved in IDD development and regulates various processes, such as inflammation, cellular senescence and apoptosis, excessive mechanical loading, metabolic disturbances, oxidative stress, calcium homeostasis imbalance, and extracellular matrix (ECM) dysregulation. This review summarizes the formation of ERS and the potential link between ERS and IDD development. ERS can be a promising new therapeutic target for the clinical management of IDD.

The Potential Role of Cytokines in Diabetic Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a major cause of low back pain. Diabetes mellitus is a chronic inflammatory disease that may cause or aggravate IVDD; however, the mechanism by which diabetes induce IVDD is currently unclear. Compared to non-diabetic individuals, diabetic patients have higher levels of plasma cytokines, especially TNF-α, IL-1β, IL-5, IL-6, IL-7, IL-10, and IL-18. Due to the crucial role of cytokines in the process of intervertebral disc degeneration, we hypothesized that elevation of these cytokines in plasma of diabetic patients may be involved in the process of diabetes-induced IVDD. In this review, changes in plasma cytokine levels in diabetic patients were summarized and the potential role of elevated cytokines in diabetes-induced IVDD was discussed. Results showed that some cytokines such as TNF-α and IL-1β may accelerate the development of IVDD, while others such as IL-10 is supposed to prevent its development. Apoptosis, senescence, and extracellular matrix metabolism were found to be regulated by these cytokines in IVDD. Further studies are required to validate the cytokines targeted strategy for diabetic IVDD therapy.

Complications in the spine associated with type 2 diabetes: The role of advanced glycation end-products

Type 2 diabetes mellitus (T2D) is an increasingly prevalent disease with numerous comorbidities including many in the spine. T2D is strongly linked with vertebral fractures, intervertebral disc (IVD) degeneration, and severe chronic spinal pain. Yet the causative mechanism for these musculoskeletal impairments remains unclear. The chronic hyperglycemic state in T2D promotes the formation of advanced glycation end-products (AGEs) in tissues, and the accumulation of AGEs may play a role in musculoskeletal complications by modifying the extracellular matrix, impairing cellular homeostasis, and perpetuating an inflammatory cascade via its receptor (RAGE). The AGE and RAGE associated alterations in extracellular matrix composition and morphological features of the vertebral bodies and IVDs are likely contributors to the incidence and severity of spinal pathologies in T2D. This review will broadly examine the effects of AGEs on tissues in the spine in the context of T2D, with an emphasis on the changes in the vertebrae and the IVD. Along with the clinical and epidemiological findings, we will provide an overview of preclinical rodent models of T2D that exhibit deficits in the IVD and vertebral bone. Elucidating the role of AGEs and RAGE will be crucial for understanding the disease mechanisms and translation therapies of musculoskeletal pathologies in T2D.

Diabetes Mellitus and the Development of Lumbar Canal Stenosis: Is There Any Relevance?

Study Design

Retrospective study.

Purpose

To assess the relationship between the severity of lumbar canal stenosis (LCS) and type-II diabetes mellitus (DM).

Overview of Literature

DM is a multiorgan disorder that has an effect on all types of connective tissues. LCS is a narrowing of the spinal canal with nerve root impingement that causes neurological claudication and radiculopathy. Identification of the risk factors of LCS is key in the prevention of its onset or progression.

Methods

LCS patients were divided into three groups as per DM status: group A without DM (n=150); group B patients with well-controlled DM; and group C patients with uncontrolled DM. Groups B and C were subdivided into group B1: patients with DM with a duration of ≤10 years (n=76), group B2: DM with duration of >10 years (n=68), group-C1 DM duration ≤10 years (n=56), and group C2 DM duration >10 years (n=48). The severity of LCS was evaluated using the Swiss Spinal Stenosis Scale (SSSS) and Modified Oswestry Disability score (MODS). Operated patients ligamentum flavum sent for histological staining and quantitative immunofluorescence analysis.

Results

The demographic data of groups did not show any difference except in age. There was no difference between the mean SSSS and MODS of groups A and B1. Groups B2, C1, and C2 had higher average SSSS and MODS than group A (p<0.05). Groups B2 and C2 had higher SSSS and MODS than groups B1 and C1. Groups C1 and C2 had higher scores than groups B1 and B2 (p<0.05). The severity of LCS was significantly related to the duration of DM in groups B and C (p<0.05). Uncontrolled and longer duration of DM had significant elastin fibers loss and also higher rate of disk apoptosis, high matrix aggrecan fragmentation, and high disk glycosaminoglycan content.

Conclusions

Longer duration and uncontrolled diabetes were risk factors for LCS and directly correlate with the severity of LCS.

High-glucose environment accelerates annulus fibrosus cell apoptosis by regulating endoplasmic reticulum stress

Diabetes mellitus (DM) is an important risk factor of intervertebral disc degeneration. However, how DM affects annulus fibrosus (AF) biology remains unclear. The present study was aimed to investigate the effects and mechanism of high glucose on AF cell biology. Rat AF cells were cultured in baseline medium and culture medium with 0.2 M glucose. The inhibitor 4-PBA was added along with the high glucose culture medium to study the role of endoplasmic reticulum (ER) stress in this process. Compared with the control cells, high glucose significantly increased cell apoptosis ratio and caspase-3/9 activity, up-regulated mRNA/protein expression of Bax and caspase-3/cleaved caspase-3, but down-regulated mRNA/protein expression of Bcl-2. Moreover, high glucose increased mRNA and protein expression of CHOP, ATF-6 and GRP78. However, once ER stress was inhibited by the inhibitor 4-PBA in the high glucose group, cell apoptosis ratio and caspase-3/9 activity were decreased, mRNA/protein expression of Bax and caspase-3/cleaved caspase-3 was down-regulated, but mRNA/protein expression of Bcl-2 was up-regulated. In conclusion, high glucose condition can promote AF cell apoptosis through inducing ER stress. The present study helps us understand the mechanism of disc degeneration in DM patients.

Canine models of spine disorders

Neck and low back pain are common among the adult human population and impose large social and economic burdens on health care and quality of life. Spine-related disorders are also significant health concerns for canine companions with etiopathogeneses, clinical presentations, and diagnostic and therapeutic options that are very similar to their human counterparts. Historically, induced and spontaneous pathology in laboratory rodents, dogs, sheep, goats, pigs, and nonhuman primates have been used for study of human spine disorders. While each of these can serve as useful preclinical models, they all have inherent limitations. Spontaneously occurring spine disorders in dogs provide highly translatable data that overcome many of the limitations of other models and have the added benefit of contributing to veterinary healthcare as well. For this scoping review, peer-reviewed manuscripts were selected from PubMed and Google Scholar searches using keywords: "intervertebral disc," "intervertebral disc degeneration," "biomarkers," "histopathology," "canine," and "mechanism." Additional keywords such as "injury," "induced model," and "nucleus degeneration" were used to further narrow inclusion. The objectives of this review were to (a) outline similarities in key features of spine disorders between dogs and humans; (b) describe relevant canine models; and (c) highlight the applicability of these models for advancing translational research and clinical application for mechanisms of disease, diagnosis, prognosis, prevention, and treatment, with a focus on intervertebral disc degeneration. Best current evidence suggests that dogs share important anatomical, physiological, histological, and molecular components of spinal disorders in humans, such that induced and spontaneous canine models can be very effective for translational research. Taken together, the peer-reviewed literature supports numerous advantages for use of canine models for study of disorders of the spine when the potential limitations and challenges are addressed.

Advanced glycation end products cause RAGE-dependent annulus fibrosus collagen disruption and loss identified using in situ second harmonic generation imaging in mice intervertebral disk in vivo and in organ culture models

Aging and diabetes are associated with increased low-back pain and intervertebral disk (IVD) degeneration yet causal mechanisms remain uncertain. Advanced glycation end products (AGEs), which accumulate in IVDs from aging and are implicated in diabetes-related disorders, alter collagen and induce proinflammatory conditions. A need exists for methods that assess IVD collagen quality and degradation in order to better characterize specific structural changes in IVDs due to AGE accumulation and to identify roles for the receptor for AGEs (RAGE). We used multiphoton microscopy with second harmonic generation (SHG), collagen-hybridizing peptide (CHP), and image analysis methods to characterize effects of AGEs and RAGE on collagen quality and quantity in IVD annulus fibrosus (AF). First, we used SHG imaging on thin sections with an in vivo dietary mouse model and determined that high-AGE (H-AGE) diets increased AF fibril disruption and collagen degradation resulting in decreased total collagen content, suggesting an early degenerative cascade. Next, we used in situ SHG imaging with an ex vivo IVD organ culture model of AGE challenge on wild type and RAGE-knockout (RAGE-KO) mice and determined that early degenerative changes to collagen quality and degradation were RAGE dependent. We conclude that AGE accumulation leads to RAGE-dependent collagen disruption in the AF and can initiate molecular and tissue level collagen disruption. Furthermore, SHG and CHP analyzes were sensitive to collagenous alterations at multiple hierarchical levels due to AGE and may be useful in identifying additional contributors to collagen damage in IVD degeneration processes.

Hyperglycemia and its influence on development of lumbar degenerative disc disease

Study Design

Objectives

Methods

Results

Conclusions

Effects of type 1 diabetes mellitus on lumbar disc degeneration: a retrospective study of 118 patients

BACKGROUND

The study aimed to investigate the correlation between type 1 diabetes (T1D) and lumbar disc degeneration (LDD).

METHODS

A retrospective analysis of 118 patients with T1D recruited from January 2014 to March 2019 was performed, and multivariate logistic regression was used to analyse the incidence of T1D; the age, sex, and body mass index (BMI) of the patients; the disease duration and the glycosylated haemoglobin and venous blood glucose levels. All patients who suffered low back pain were assessed by MRI using the Pfirrmann grading system.

RESULTS

A total of 118 patients with an average age of 36.99 ± 17.01 (8-85 years) were reviewed. The mean hospitalization duration, venous glucose fluctuation range, glycated haemoglobin level, highest venous glucose level, venous glucose level, and disease course duration were 13.98 ± 10.16 days, 14.99 ± 5.87 mmol/L, 9.85 ± 2.52 mmol/L, 25.29 ± 7.92 mmol/L, 13.03 ± 5.75 mmol/L and 7.30 ± 8.41 years. The average Pfirrmann scores of the different discs were 2.20 ± 0.62 (L1-2), 2.35 ± 0.67 (L2-3), 2.90 ± 0.45 (L3-4), 4.20 ± 0.52 (L4-5) and 4.10 ± 0.72 (L5-S1). The patients with T1D showed severe disc degeneration. The male sex, glycosylated haemoglobin, venous glucose and venous glucose fluctuations were significantly associated with LDD (P < 0.05).

CONCLUSIONS

Glycosylated haemoglobin, the male, venous glucose and the venous glucose fluctuation range were risk factors for LDD.

Does Type II Diabetes Induce Early Senescence and Degeneration in Human Intervertebral Discs? A Tissue Biomarker Evaluation

Background

Diabetes mellitus is one of the leading causes of morbidity resulting in multi-organ dysfunction. Animal studies have shown that hyperglycemia results in stress-induced senescence through the p16-pRb pathway, thereby accelerating early disc degeneration. There is a paucity of literature on the effect of hyperglycemia in human intervertebral disc cells. We aimed to analyze the effect of diabetes mellitus in human intervertebral disc cells.

Methods

This is a prospective study done in patients with degenerative disc disease. Patients were categorized into a control group (no diabetes: 26 patients) and a study group (type 2 diabetes for > 3 years: 24 patients). All patients underwent either discectomy or transforaminal lumbar interbody fusion and the removed disc was transported to pathology department. Tissue was prepared and histopathological grading was done followed by immunohistochemistry studies using antibodies for MMP-1, p21, p16, and pRb.

Results

Samples from diabetic patients had severe (grade 2) degenerative changes compared with the control group (grade 1). Changes were more intense in the nucleus pulposus with increased cellularity and clustering of chondrocytes, and disorganization and loss of nuclear matrix. Immunohistochemical staining for MMP1, p16, and pRb was more intense (Q score = 4) whereas the staining for p21 was less intense (Q score = 1) in the diabetic group compared with the control group.

Conclusion

Our study demonstrates that type 2 diabetes mellitus accelerates stress-induced senescence in human intervertebral discs resulting in early disc degeneration. Also, the severity of disc degeneration is severe compared with the normal subjects.

Clinical Relevance

Hyperglycemia can affect the intervertebral discs similar to other organs and hence adequate control of blood glucose in diabetics can prevent the disc degeneration, which is the initiator of degeneration cascade in spine.

Leptin signaling and the intervertebral disc: Sex dependent effects of leptin receptor deficiency and Western diet on the spine in a type 2 diabetes mouse model

Type 2 diabetes and obesity are associated with back pain in juveniles and adults and are implicated in intervertebral disc (IVD) degeneration. Hypercaloric Western diets are associated with both obesity and type 2 diabetes. The objective of this study was to determine if obesity and type 2 diabetes result in spinal pathology in a sex-specific manner using in vivo diabetic and dietary mouse models. Leptin is an appetite-regulating hormone, and its deficiency leads to polyphagia, resulting in obesity and diabetes. Leptin is also associated with IVD degeneration, and increased expression of its receptor was identified in degenerated IVDs. We used young, leptin receptor deficient (Db/Db) mice to mimic the effect of diet and diabetes on adolescents. Db/Db and Control mice were fed either Western or Control diets, and were sacrificed at 3 months of age. Db/Db mice were obese, while only female mice developed diabetes. Female Db/Db mice displayed altered IVD morphology, with increased intradiscal notochordal band area, suggesting delayed IVD cell proliferation and differentiation, rather than IVD degeneration. Motion segments from Db/Db mice exhibited increased failure risk with decreased torsional failure strength. Db/Db mice also had inferior bone quality, which was most prominent in females. We conclude that obesity and diabetes due to impaired leptin signaling contribute to pathological changes in vertebrae, as well as an immature IVD phenotype, particularly of females, suggesting a sex-dependent role of leptin in the spine.

Amyloid protein aggregation in diabetes mellitus accelerate intervertebral disc degeneration

Diabetes is one of the risk factors for disc degeneration, but the exact mechanism is still unclear. Misfolding and aggregation of human islet amyloid polypeptide (hIAPP) is an important factor in diabetes. hIAPP proteins misfold from monomers to β-sheet-rich oligomers, destroy the permeability of the cell membrane and cause abnormal cell function and death. Under the pathological state of diabetes, hIAPP oligomers can promote the expression and secretion of the inflammatory factor IL-1β, while IL-1β-mediated inflammatory response is the pathogenesis basis of intervertebral disc degeneration. Thus, amyloid hIAPP aggregation accelerates disc degeneration in the pathological state of diabetes.

Long non‑coding RNA MALAT1 promotes high glucose‑induced rat cartilage endplate cell apoptosis via the p38/MAPK signalling pathway

Diabetes mellitus (DM) contributes to intervertebral disc degeneration (IDD). The long non‑coding RNA MALAT1 has been revealed to play an important role in diabetes‑associated complications. However, the specific role of MALAT1 in diabetes‑associated IDD has not been determined. The aim of the present study was to evaluate the roles of MALAT1 in the apoptosis of cartilage endplate (CEP) cells induced by high glucose and to explore the mechanisms underlying this effect. Rat CEP cells were cultured in high‑glucose medium (25 mM glucose) for 24 or 72 h. Cells cultured in medium containing 5 mM glucose were used as a control. Flow cytometry was used to detect the degree of apoptosis. Reverse transcription‑quantitative PCR was used to measure the expression of MALAT1 mRNA. In addition, CEP cells were treated with different conditions (high glucose, high glucose + MALAT1 negative control, high glucose + MALAT1 RNAi, normal control) for 72 h. Flow cytometry was subsequently used to detect apoptosis and western blotting was used to measure the expression levels of total and phosphorylated p38. The results revealed that high glucose concentration promoted apoptosis and enhanced expression of MALAT1 in CEP cells. Furthermore, MALAT1 knockout decreased the expression levels of total and phosphorylated p38 and reduced the apoptosis of rat CEP cells. The results obtained in the present study indicated that MALAT1 may serve as an important therapeutic target for curing or delaying IDD in patients with diabetes.

The role of estrogen in intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is a main contributor to low back and radicular pain, which imposes heavy economic burdens on society. However, the etiology and mechanism of IVDD are complex and still not completely clear. In particular, the role of estrogen in IVDD has not received much attention in recent research, although estrogen plays a crucial role in the metabolic dysfunction of others musculoskeletal structures, such as bone, muscle, and tendon. In this review, we attempt to describe the role of estrogen in IVDD and to summarize the proposed mechanisms in vivo and in vitro, as well as, to outline several interesting questions in this field.

The effect of high glucose on the biological characteristics of nucleus pulposus-derived mesenchymal stem cells

Diabetes mellitus (DM) is a dependent risk factor in the progression of intervertebral disc degeneration (IVDD). High glucose supply has negative effects on nucleus pulpous (NP) cell and mesenchymal stem cell (MSC) biology. However, the effect of hyperglycaemia on the biological characterization of nucleus pulpous-derived mesenchymal stem cell (NPMSC) has not been investigated previously. Therefore, further exploration of the effects of DM-associated hyperglycaemia on NPMSC biology is important to better understand and develop endogenous repair strategies of DM patient-associated IVDD. Therefore, the cell biological characteristics were compared between NPMSC cultured in media with low glucose concentration (LG-NPMSC) and high glucose concentration (HG-NPMSC). The results demonstrated that HG-NPMSC showed significantly decreased cell proliferation, colony formation ability, migration and wound-healing capability compared with those of LG-NPMSC. HG-NPMSC also showed significantly decreased expressions of stemness genes and mRNA and protein expressions of silent information regulator protein 1 (SIRT1), SIRT6, hypoxia inducible factor-1α (HIF-1α) and glucose transporter 1 (GLUT-1), whereas increased cell apoptosis, cell senescence and caspase-3 expression. These results suggest that high glucose may decrease proliferation and stemness maintenance ability and increase apoptosis and senescence of NPMSC. SIGNIFICANCE OF THE STUDY: We found that high glucose concentration significantly decreased cell proliferation, colony formation ability, migration and wound-healing capability of nucleus pulposus-derived mesenchymal stem cells. Moreover, high glucose cultured nucleus pulposus-derived mesenchymal stem cells showed significantly decreased expression of stemness genes, related mRNA and protein, whereas increased cell apoptosis, cell senescence and expression of caspase-3. The present study indicated that better control of high concentration glucose in the early stage of diabetes mellitus should be recommended to prevent or limit intervertebral disc degeneration.

Glucose regulates tissue-specific chondro-osteogenic differentiation of human cartilage endplate stem cells via O-GlcNAcylation of Sox9 and Runx2

BACKGROUND

The degenerative disc disease (DDD) is a major cause of low back pain. The physiological low-glucose microenvironment of the cartilage endplate (CEP) is disrupted in DDD. Glucose influences protein O-GlcNAcylation via the hexosamine biosynthetic pathway (HBP), which is the key to stem cell fate. Thiamet-G is an inhibitor of O-GlcNAcase for accumulating O-GlcNAcylated proteins while 6-diazo-5-oxo-L-norleucine (DON) inhibits HBP. Mechanisms of DDD are incompletely understood but include CEP degeneration and calcification. We aimed to identify the molecular mechanisms of glucose in CEP calcification in DDD.

METHODS

We assessed normal and degenerated CEP tissues from patients, and the effects of chondrogenesis and osteogenesis of the CEP were determined by western blot and immunohistochemical staining. Cartilage endplate stem cells (CESCs) were induced with low-, normal-, and high-glucose medium for 21 days, and chondrogenic and osteogenic differentiations were measured by Q-PCR, western blot, and immunohistochemical staining. CESCs were induced with low-glucose and high-glucose medium with or without Thiamet-G or DON for 21 days, and chondrogenic and osteogenic differentiations were measured by Q-PCR, western blot, and immunohistochemical staining. Sox9 and Runx2 O-GlcNAcylation were measured by immunofluorescence. The effects of O-GlcNAcylation on the downstream genes of Sox9 and Runx2 were determined by Q-PCR and western blot.

RESULTS

Degenerated CEPs from DDD patients lost chondrogenesis, acquired osteogenesis, and had higher protein O-GlcNAcylation level compared to normal CEPs from LVF patients. CESC chondrogenic differentiation gradually decreased while osteogenic differentiation gradually increased from low- to high-glucose differentiation medium. Furthermore, Thiamet-G promoted CESC osteogenic differentiation and inhibited chondrogenic differentiation in low-glucose differentiation medium; however, DON acted opposite role in high-glucose differentiation medium. Interestingly, we found that Sox9 and Runx2 were O-GlcNAcylated in differentiated CESCs. Finally, O-GlcNAcylation of Sox9 and Runx2 decreased chondrogenesis and increased osteogenesis in CESCs.

CONCLUSIONS

Our findings demonstrate the effect of glucose concentration on regulating the chondrogenic and osteogenic differentiation potential of CESCs and provide insight into the mechanism of how glucose concentration regulates Sox9 and Runx2 O-GlcNAcylation to affect the differentiation of CESCs, which may represent a target for CEP degeneration therapy.

The Sirt1/P53 Axis in Diabetic Intervertebral Disc Degeneration Pathogenesis and Therapeutics

Intervertebral disc degeneration (IDD) is one of the major causes of low back pain. Diabetes is a risk factor for IDD and may aggravate IDD in rats; however, the mechanism is poorly understood. Previously, we demonstrated that apoptosis and senescence were increased in diabetic nucleus pulposus (NP) tissues; in the current study, we found that hyperglycaemia may promote the incidence of apoptosis and senescence in NP cells in vitro. Meanwhile, the acetylation of P53, a master transcription factor of apoptosis and senescence, was also found increased in diabetic NP tissues in vivo as well as in hyperglycaemic NP cells in vitro. Sirt1 is an NAD⁺-dependent deacetylase, and we showed that the expression of Sirt1 was decreased in NP tissues, while hyperglycaemia could suppress the expression and activity of Sirt1 in NP cells. Furthermore, we demonstrated that butein may inhibit acetylation of P53 and protect NP cells against hyperglycaemia-induced apoptosis and senescence through Sirt1 activation, as the Sirt1 inhibitor Ex527 may counteract the protective effect of butein in hyperglycaemic NP cells. An in vivo study showed that butein could ameliorate the IDD process in diabetic rats, while Sirt1 was increased and acetyl-p53 was decreased in NP tissues in butein-treated rats. These results indicate that the Sirt1/P53 axis is involved in the pathogenesis of diabetic IDD and may serve as a therapeutic target for diabetic IDD.

High glucose promotes annulus fibrosus cell apoptosis through activating the JNK and p38 MAPK pathways

Diabetes mellitus (DM) is an important risk factor of intervertebral disc degeneration. A high glucose niche-mediated disc cell apoptosis is an implicate causative factor for the spine degenerative diseases related with DM. However, the effects of a high glucose niche on disc annulus fibrosus (AF) cell apoptosis and the potential signaling transduction pathway is unclear. The present study is to investigate the effects of high glucose on disc AF cell apoptosis and the role of two potential signaling pathways in this process. Rat AF cells were cultured in baseline medium or medium with different concentrations (0.1 and 0.2 M) of glucose for 3 days. Flow cytometry was used to assess the degree of apoptosis. Activity of caspase 3/9 was evaluated by chemical kit. Expression of pro-apoptotic and anti-apoptotic molecules was analyzed by real-time polymerase chain reaction and Western blot. In addition, activity of the C-Jun NH₂-terminal kinases (JNK) pathway and p38 mitogen-activated protein kinase (MAPK) pathway was evaluated by Western blot. Compared with the control group, high glucose culture increased cell apoptosis ratio and caspase-3/9 activity, up-regulated expression of bax, caspase-3, cleaved caspase-3 and cleaved PARP, and down-regulated expression of bcl-2 in a glucose concentration-dependent manner. Additionally, high glucose culture increased expression of the p-JNK and p-p38 MAPK in a concentration-dependent manner. Further results showed that inhibition of the JNK or p38 MAPK pathway attenuated the effects of high glucose on AF cell apoptosis. Together, high glucose promoted disc AF cell apoptosis through regulating the JNK pathway and p38 MAPK pathway in a glucose concentration-dependent manner.

Diabetes mellitus as a risk factor for intervertebral disc degeneration: a critical review

PURPOSE

To examine to what extent diabetes mellitus (DM) is implicated as a distinct mechanism in intervertebral disc degeneration (IVDD).

METHODS

The published clinical and laboratory data relevant to this matter are critically reviewed. A total of 12 clinical studies evaluate the association between DM and degenerative changes such as IVDD, spinal stenosis (SS) and IVD herniation. A total of 34 laboratory research papers evaluate the association between DM and IVDD.

RESULTS

There are 7 studies that correlate DM with IVDD, 4 of them showing that DM is a significant risk factor for degeneration, and 3 of them failing to establish any association. Three studies demonstrate significant association between DM and SS. However, 2 of these studies also include patients with IVD herniation that failed to demonstrate any correlation with DM. Two other studies indicate a significant association between DM and lumbar disc herniation. Multiple different mechanisms, acting independently or interactively, cause tissue damage leading to IVDD including: microangiopathy of the subchondral vertebral endplate, cellular senescence, cell death (through apoptosis or autophagy), hyperglycaemia, advance glycation end products, adipokines, and cytokines (through oxidative, osmotic, and inflammatory mechanisms).

CONCLUSION

The clinical evidence is not consistent, but weakly supports the relationship between DM and IVDD. However, the laboratory studies consistently suggest that DM interferes with multipronged aberrant molecular and biochemical pathways that provoke IVDD. Taken as a whole, the strong laboratory evidence and the weak clinical studies implicate DM as a distinct contributing factor for IVDD. These slides can be retrieved under Electronic Supplementary Material.

Mitochondrial Pathway Is Involved in Advanced Glycation End Products-Induced Apoptosis of Rabbit Annulus Fibrosus Cells

STUDY DESIGN

Experimental study.

OBJECTIVE

The purposes of this study were to evaluate whether advanced glycation end-products (AGEs) induce annulus fibrosus (AF) cell apoptosis and further to explore the mechanism by which this process occurs.

SUMMARY OF BACKGROUND DATA

Recent studies revealed that AGEs accumulation is considered an important factor in diabetic intervertebral disc (IVD) degeneration. However, the effect of AGEs on intervertebral disc remains unclear.

METHODS

AF cells were treated with various concentrations of AGEs for 3 days. Cell viability and cell proliferation were measured by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assays, respectively. Cell apoptosis was examined by Annexin V/PI apoptosis detection kit and Hoechst 33342. The expression of apoptosis-related proteins, including Bax, Bcl-2, cytochrome c, caspase-3, and caspase-9, was detected by western blotting. In addition, Bax and Bcl-2 mRNA expression levels were detected by real-time PCR (RT-PCR). Mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) production of AF cell were examined by 5,5',6,6' -Tetrachloro-1,1',3,3'- tetraethyl-imidacarbocyanine iodide (JC-1) staining and 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probes, respectively.

RESULTS

Our results indicated that AGEs had inhibitory effects on AF cell proliferation and induced AF cell apoptosis. The molecular data showed that AGEs significantly up-regulated Bax expression and inhibited Bcl-2 expression. In addition, AGEs increased the release of cytochrome c into the cytosol and enhanced caspase-9 and caspase-3 activation. Moreover, treatment with AGEs resulted in a decrease in MMP and the accumulation of intracellular ROS in AF cells. The antioxidant N-acetyl-L-cysteine (NAC) significantly reversed AGE-induced MMP decrease and AF cell apoptosis.

CONCLUSION

These results suggested that AGEs induce rabbit AF cell apoptosis and mitochondrial pathway may be involved in AGEs-mediated cell apoptosis, which may provide a theoretical basis for diabetic IVD degeneration.

LEVEL OF EVIDENCE

N/A.

Influence of diabetes mellitus on patients with lumbar spinal stenosis: A nationwide population-based study

Purpose

To evaluate the relationship between comorbidities, medical cost, and surgical outcome in patients with lumbar spinal stenosis (LSS) and diabetes mellitus (DM).

Methods

Data on patients with LSS (n = 14,298) were collected from the Korean National Health Insurance Service database from 2005 to 2007. After 8 years of follow-up, a “DM group” (n = 3,478) and a “non-DM group” (n = 10,820) were compared according to outcome measures. Cox proportional hazard regressions were performed to examine the relationship between DM, hypertension (HTN), cardiovascular disease (CVD), chronic kidney disease (CKD), cerebrovascular disease (CbVD), and surgery for LSS. The admission rate and medical cost as well asthe overall survival rate for those who underwent lumbar surgery were also assessed among patients with DM and LSS.

Results

Mortality was about 1.35 times higher in the DM group than in the non-DM group. Patients with DM and comorbidities including HTN (hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.25–1.56; p<0.001), CVD (HR, 1.53; 95% CI, 1.36–1.73; p<0.001), CKD (HR, 3.18; 95% CI, 2.7–3.76; p<0.001), and CbVD (HR, 1.69; 95% CI, 1.49–1.91; p<0.001) showed an increased risk of mortality. The mean hospitalization time and average medical cost of patients with DM who underwent lumbar surgery were 60.8 days, and 7,127 USD, respectively. This was 31.3 days longer, and 6,207 USD higher, respectively, than those of patients with DM who underwent conservative treatment for LSS. Within the DM group, the survival rate of surgical management of LSS had a significant tendency for positive prognosis compared with those administered conservative treatment (p = 0.046).

Conclusions

In patients with LSS, DM was associated both with poor prognosis (most significantly in those with CKD), and increased medical cost in those who underwent surgery. Nevertheless, surgical treatment for LSS in patients with DM was related to favorable prognosis compared with conservative treatment.

Is there an association between diabetes and neck and back pain? A systematic review with meta-analyses

Background and objective

Approximately half of the population will experience either low back pain or neck pain, at some point in their lives. Previous studies suggest that people with diabetes are more likely to present with chronic somatic pain, including shoulder, knee and spinal pain. This study aimed to systematically review and appraise the literature to explore the magnitude as well as the nature of the association between diabetes and back, neck, or spinal (back and neck) pain.

Databases and data treatment

A systematic search was performed using the Medline, CINAHL, EMBASE, and Web of Science electronic databases. Studies which assessed the association between diabetes and back or neck pain outcomes, in participants older than 18 years of age were included. Two independent reviewers extracted data on the incidence of pain and reported associations.

Results

Eight studies were included in the meta-analyses. Meta-analyses showed that people with diabetes are more likely to report low back pain [5 studies; n: 131,431; odds ratio (OR): 1.35; 95% Confidence Interval (CI): 1.20 to 1.52; p<0.001] and neck pain (2 studies; n: 6,560; OR: 1.24; 95% CI: 1.05 to 1.47; p = 0.01) compared to those without diabetes. Results from one longitudinal cohort study suggested that diabetes is not associated with the risk of developing future neck, low back or spinal pain.

Conclusions

Diabetes is associated with low back and neck individually, and spinal pain. The longitudinal analysis showed no association between the conditions. Our results suggest that diabetes co-exists with back pain; however, a direct causal link between diabetes and back pain was not established.

Systematic review registration

PROSPERO registration CRD42016050738.

Elevated glycohemoglobin HbA1c is associated with low back pain in nonoverweight diabetics

BACKGROUND CONTEXT

Low back pain (LBP) is a common complaint in clinical practice of multifactorial origin. Although obesity has been thought to contribute to LBP primarily by altering the distribution of mechanical loads on the spine, the additional contribution of obesity-related conditions such as diabetes mellitus (DM) to LBP has not been thoroughly examined.

PURPOSE

To determine if there is a relationship between DM and LBP that is independent of body mass index (BMI) in a large cohort of adult survey participants.

STUDY DESIGN

Retrospective analysis of prospectively collected National Health and Nutrition Examination Survey (NHANES) data to characterize associations between LBP, DM, and BMI in adults subdivided into 6 subpopulations: normal weight (BMI 18.5-25), overweight (BMI 25-30), and obese (BMI >30) diabetics and nondiabetics. Diabetes was defined with glycohemoglobin A1c (HbA1c) ≥6.5%.

PATIENT SAMPLE

11,756 participants from NHANES cohort.

OUTCOME MEASURES

Percentage of LBP reported.

METHODS

LBP reported in the 1999-2004 miscellaneous pain NHANES questionnaire was the dependent variable examined. Covariates included HbA1c, BMI, age, and family income ratio to poverty as continuous variables as well as race, gender, and smoking as binary variables. Individuals were further subdivided by weight class and diabetes status. Regression and graphical analyses were performed on the study population as a whole and also on subpopulations.

RESULTS

Increasing HbA1c did not increase the odds of reporting LBP in the full cohort. However, multivariate logistic regression of the 6 subpopulations revealed that the odds of LBP significantly increased with increasing HbA1c levels in normal weight diabetics. No other subpopulations reported significant relationships between LBP and HbA1c. LBP was also significantly associated with BMI for normal weight diabetics and also for obese subjects regardless of their DM status.

CONCLUSIONS

LBP is significantly related to DM status, but this relationship is complex and may interact with BMI. These results support the concept that LBP may be improved in normal weight diabetic subjects with improved glycemic control and weight loss, and that all obese LBP subjects may benefit from improved weight loss alone.

Dietary advanced glycation end-product consumption leads to mechanical stiffening of murine intervertebral discs

Back pain is a leading cause of disability and is strongly associated with intervertebral disc (IVD) degeneration. Reducing structural disruption and catabolism in IVD degeneration remains an important clinical challenge. Pro-oxidant and structure-modifying advanced glycation end-products (AGEs) contribute to obesity and diabetes, which are associated with increased back pain, and accumulate in tissues due to hyperglycemia or ingestion of foods processed at high heat. Collagen-rich IVDs are particularly susceptible to AGE accumulation due to their slow metabolic rates, yet it is unclear whether dietary AGEs can cross the endplates to accumulate in IVDs. A dietary mouse model was used to test the hypothesis that chronic consumption of high AGE diets results in sex-specific IVD structural disruption and functional changes. High AGE diet resulted in AGE accumulation in IVDs and increased IVD compressive stiffness, torque range and failure torque, particularly for females. These biomechanical changes were likely caused by significantly increased AGE crosslinking in the annulus fibrosus, measured by multiphoton imaging. Increased collagen damage measured with collagen hybridizing peptide did not appear to influence biomechanical properties and may be a risk factor as these animals age. The greater influence of high AGE diet on females is an important area of future investigation that may involve AGE receptors known to interact with estrogen. We conclude that high AGE diets can be a source for IVD crosslinking and collagen damage known to be important in IVD degeneration. Dietary modifications and interventions that reduce AGEs warrant further investigation and may be particularly important for diabetics, in whom AGEs accumulate more rapidly.

Summary: Dietary AGEs lead to sex-specific intervertebral disc structural and functional changes and may be targeted for promoting spinal health, especially in diabetes, in which AGEs form rapidly.

APOPTOSIS, NUTRITION, AND METABOLISM OF TRANSPLANTED INTERVERTEBRAL DISC CELLS

ABSTRACT Introduction: Apoptosis is a contributing factor to degenerating intervertebral disc (IVD). Disc regeneration has been attempted by transplanting cells into the disc, with some gains in disc height achieved in animal models. Here, we study whether the apoptotic microenvironment affects the transplanted disc cells. Methods: Human annulus fibrosus (AF) and nucleus pulposus (NP) cells were grown in media then starved for 5 days in vitro by not changing the media. Three aspects of apoptotic cell influence on the transplanted cells were tested in a total of 32 samples: 1) the effect of apoptotic cytokines in the media, 2) reduced glucose in the media, and 3) apoptotic cell bodies in the flask. The Trypan Blue, AlamarBlue®, and 1,9-Dimethyl-Methylene Blue assays for sulfated glycosaminoglycan (sGAG) content were performed (n=4). Results: There were significant decreases in cell viability between the control, 25% conditioned media (CM) and starved control group. There were no significant differences in cell number, metabolic activity or sGAG production in cells grown in different conditioned media compared to cells grown in complete media. The cells of the control decreased in viability and number over the 5 days without feeding, then improved dramatically when feeding was resumed. Flasks that received transplanted cells in addition to renewed feeding did not recover as much as the cells in the re-fed group. Conclusions: Cytokines from starved cells negatively impact on the viability of healthy cells. Starving cells that receive new sources of nutrition have even higher viability than transplanted cells. This indicates that altering and improving the nutrient supply problem in the IVD could be a valuable option. Level of Evidence III; Case control studyg.

Lumbar Schmorl's Nodes and Their Correlation with Spine Configuration and Degeneration

The aim of this study was to reveal whether demographic aspect, vertebral morphometry, and spine degeneration are associated with lumbar Schmorl's nodes (SNs). A retrospective cross-sectional study was performed using data from the Department of Radiology (Carmel, Medical Center, Israel) for 180 individuals: age range between 40 and 99 years; 90 males and 90 females. All participants had undergone high-resolution CT scans for abdominal diagnostic purposes in the same supine position prior to our study, which enabled the processing of the scans in all planes and allowed a 3D reconstruction of the lower lumbar region. Eighty individuals (44.4%) had at least one SN along the lumbar spine, particularly at L3-4 level (30%). Vertebral body length (L1 to L3) and width (L1 and L4) were significantly greater in the SNs group compared to non-SNs group. On contrast, disc height (L3-4 and L4-5) was significantly lesser in SNs group than non-SNs group. SNs was significantly associated with smoking (X²= 4.436, P=0.02) and degenerative lumbar spinal stenosis (X²= 5.197, P=0.038). Moreover, the prevalence of SN was significantly greater in individuals with vacuum phenomenon and osteophytes formation (L1-2 to L4-5 levels). This study indicates that vacuum phenomenon on L3-4 (OR: 4.7, P=0.034), smoking habit (OR: 3.2, P=0.003), disc height loss of L4-5 (OR: 0.798, P=0.008), vertebral body length of L1 (OR: 1.37, P<0.001), and age (OR: 1.05, P=0.002) increase the probability of developing lumbar SNs.

Factors Affecting Early and 1-Year Motor Recovery Following Lumbar Microdiscectomy in Patients with Lumbar Disc Herniation: A Prospective Cohort Review

Study Design

Prospective cohort study.

Purpose

The study was aimed at evaluating clinicoradiological factors affecting recovery of neurological deficits in cases of lumbar disc herniation (LDH) treated by lumbar microdiscectomy.

Overview of Literature

The majority of the available literature on neurological recovery following neurodeficit is limited to retrospective series. The literature is currently limited regarding variables that can help predict the recovery of neurodeficits following LDH.

Methods

A prospective analysis was performed on 70 consecutive patients who underwent lumbar microdiscectomy (L1–2 to L5–S1) owing to neurological deficits due to LDH. Patients with motor power ≤3/5 in L2–S1 myotomes were considered for analysis. Follow-up was performed at 2, 6, and 12 months to note recovery of motor deficits. Clinicoradiological parameters were compared between the recovered and nonrecovered groups.

Results

A total of 65 patients were available at the final follow-up: 41 (63%) had completely recovered by 2 months; four showed delayed recovery at the 6-month follow-up; and 20 (30.7%) showed no recovery at 1 year. Clinicoradiological factors, including diabetes, complete initial deficit, areflexia, multilevel disc prolapse, longer duration since initial symptoms, and ≥2 previous symptomatic episodes were associated with a significant risk of poorer recovery (p<0.05 for all). Age, sex, occupation, smoking, level/type or location of disc herniation, primary canal stenosis, disc fragment dimensions, precipitating factors, bladder involvement, bilaterality of symptoms, and the presence or absence of anal reflex did not affect neurological recovery (p>0.05 for all). Diabetes mellitus (p=0.033) and complete initial motor deficit (p=0.028) were significantly associated with delayed recovery in the multivariate analysis.

Conclusions

The overall neurological recovery rate in our study was 69%. Diabetes mellitus (p=0.033) and complete initial motor deficit were associated with delayed motor recovery.

Therapeutic Potential of Naringin for Intervertebral Disc Degeneration: Involvement of Autophagy Against Oxidative Stress-Induced Apoptosis in Nucleus Pulposus Cells

Intervertebral disc degeneration (IDD) is a major cause of lower back pain, but few efficacious medicines have been developed for IDD. Increased nucleus pulposus cells apoptosis is a dominant pathogenesis of IDD and is considered a therapeutic target. Previously, our group proved that autophagy may protect nucleus pulposus cells against apoptosis. As one of the major bioflavonoids of citrus, naringin activates autophagy. Therefore, we hypothesize that naringin may have therapeutic potential for IDD by activating autophagy in nucleus pulposus cells. In this study, we evaluated the effects of naringin on TBHP-induced oxidative stress in nucleus pulposus cells in vitro as well as in puncture-induced rat IDD model in vivo. Our results showed that naringin could reduce the incidence of oxidative stress-induced apoptosis in nucleus pulposus cells and promoted the expression of autophagy markers LC3-II/I and beclin-1. Meanwhile, inhibition of autophagy by 3-MA may partially reverse the anti-apoptotic effect of naringin, indicating that autophagy was involved in the protective effect of naringin in nucleus pulposus cells. Further study showed that autophagy regulation of naringin may be related to AMPK signaling. Also, we found that naringin treatment can regulate the expression of collagen II, aggrecan and Mmp13 to sustain the extracellular matrix. Furthermore, our in vivo study showed that naringin can ameliorate IDD in puncture-induced rat model. In conclusion, our study suggests that naringin can protect nucleus pulposus cells against apoptosis and ameliorate IDD in vivo, the mechanism may relate to its autophagy regulation.

High glucose-induced excessive reactive oxygen species promote apoptosis through mitochondrial damage in rat cartilage endplate cells

Diabetes mellitus (DM) is an important factor in intervertebral disc degeneration (IDD). Apoptosis of cartilage endplate (CEP) cells is one of the initiators of IDD. However, the effects of high glucose on CEP cells are still unknown. Therefore, we conducted the present study to evaluate the effects of high glucose on CEP cells and to identify the mechanisms of those effects. Rat CEP cells were isolated and cultured in 10% foetal bovine serum (FBS, normal control) or high-glucose medium (10% FBS + 0.1 M glucose or 10% FBS + 0.2 M glucose, experimental conditions) for 1 or 3 days. In addition, CEP cells were treated with 0.2 M glucose for 3 days in the presence or absence of alpha-lipoic acid (ALA, 0.15 M). Flow cytometry was performed to identify and quantify the degree of apoptosis. The expression of reactive oxygen species (ROS) was assessed by flow cytometry, and mitochondrial damage (mitochondrial membrane potential) was assessed by fluorescence microscopy. Furthermore, the expression levels of cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, and cytochrome c were evaluated by Western blotting. High glucose significantly increased apoptosis and ROS accumulation in CEP cells in a dose- and time-dependent manner. Meanwhile, a disrupted mitochondrial membrane potential was detected in rat CEP cells cultured in the two high glucose concentrations. Incubating in high glucose enhanced the expression levels of cleaved caspase-3, cleaved caspase-9, Bax, and cytochrome c but decreased the level of the anti-apoptotic protein Bcl-2. ALA inhibited the expression of cleaved caspase-3, cleaved caspase-9, Bax, and cytochrome c but enhanced the expression of Bcl-2. ALA also prevented disruption of the mitochondrial membrane potential in CEP cells. This study demonstrates that high glucose-induced excessive reactive oxygen species promote mitochondrial damage, thus causing apoptosis in rat CEP cells in a dose- and time-dependent manner. ALA could prevent mitochondrial damage and apoptosis caused by high glucose in CEP cells. The results suggest that appropriate blood glucose control may be the key to preventing IDD in diabetic patients. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2476-2483, 2018.

Resveratrol attenuates high glucose-induced nucleus pulposus cell apoptosis and senescence through activating the ROS-mediated PI3K/Akt pathway

Background: Diabetes mellitus is closely correlated with disc degeneration. Nucleus pulposus (NP) cell apoptosis and senescence are typical cellular features within the degenerative disc. Resveratrol is a newly identified phytoalexin that has protective effects on cartilaginous tissue.

Objective: To investigate the whether resveratrol can protect against high glucose-induced NP cell apoptosis and senescence, and the potential mechanism in this process.

Methods: Rat NP cells were cultured in either 10% FBS culture medium (control group) or 10% FBS with a high glucose concentration (0.2 M, experiment group) for 3 days. Resveratrol or the combination of resveratrol and LY294002 was added into the culture medium of experiment group to investigate the effects of resveratrol and the PI3K/Akt pathway.

Results: High glucose significantly promoted NP cell apoptosis and NP cell senescence compared with the control group. Resveratrol exhibited protective effects against high glucose-induced NP cell apoptosis and senescence. Further analysis showed that resveratrol suppressed reactive oxygen species (ROS) generation and increased the activity of the PI3K/Akt pathway under the high glucose condition. However, the LY294002 had no significant effects on ROS content in the resveratrol-treated high glucose group.

Conclusion: Resveratrol can attenuate high glucose-induced NP cell apoptosis and senescence, and the activation of ROS-mediated PI3K/Akt pathway may be the potential mechanism in this process.

The potential effect of type 2 diabetes mellitus on lumbar disc degeneration: a retrospective single-center study

Background

Diabetes mellitus (DM) and low back pain which is mainly caused by degeneration of the intervertebral discs (IVDs) both are major public health problem worldwide. The present study was designed to investigate the association between type 2 diabetes mellitus (T2D) and severity of lumbar disc degeneration (LDD).

Methods

We retrospectively reviewed patients with low back pain visiting our spine clinic in 2014. Low back pain patients all have the lumbar MRI imaging and no previous treatment. One hundred fifty patients without T2D (group A) and 622 patients with T2D meeting the criteria were included. Sex, age, body mass index (BMI), high blood pressure (HBP), history of smoking, alcohol use, and duration of T2D were recorded. Patients with T2D were assigned to a well-controlled group (group B, n = 380) and a bad-controlled group (group C, n = 242). In group B, T2D duration of 148 patients was ≤ 10 years (group B1) and 232 patients > 10 years (group B2). In group C, T2D duration of 100 patients was ≤ 10 years (group C1) and 142 patients > 10 years (group C2). The severity of LDD was evaluated using the five-level Pfirrmann grading system. Data were analyzed using SPSS 19.0.

Results

Demographic data except age showed no difference among groups (P > 0.5). Compared to patients without T2D, patients with T2D showed more severe disc degeneration after removal of age effects (P < 0.05). From L1/2 to L5/S1, the average Pfirrmann scores between groups A and B1 showed no difference(P > 0.05); groups B2, C1, and C2 showed higher average Pfirrmann scores than group A (P < 0.05). Groups B2 and C2 showed higher average Pfirrmann scores than groups B1 and C1 (P < 0.05). Groups C1 and C2 showed higher average Pfirrmann scores than groups B1 and B2 (P < 0.05). From L1/2 to L5/S1, the severity of LDD was highly positively related to T2D duration both in groups B and C (P < 0.05).

Conclusions

T2D duration > 10 years and a bad control of T2D were risk factors for LDD. The longer T2D duration was, the more severe disc degeneration would be.

High Glucose Induces Autophagy through PPARγ-Dependent Pathway in Human Nucleus Pulposus Cells

Diabetes mellitus is a multiorgan disorder affecting many types of connective tissues, including bone and cartilage. High glucose could accelerate the autophagy in nucleus pulposus (NP) cells. In our present study, we investigated whether peroxisome proliferator-activated receptor γ (PPAR-γ) pathway is involved into autophagy regulation in NP cells under high glucose condition. After NP cells were treated with different high glucose concentrations for 72 hours, the rate of autophagy increased. Moreover, the levels of PPARγ, Beclin-1, and LC3II were significantly increased and p62 was significantly decreased compared to control group. Then, NP cells were treated with high glucose plus PPARγ agonist or PPARγ antagonist, respectively. The rate of autophagy and the levels of Beclin-1 and LC3II increased, but p62 decreased when PPARγ agonist was used. On the contrary, the rate of autophagy and the levels of Beclin-1 and LC3II decreased, while p62 increased when PPARγ antagonist was added. These results suggested that autophagy induced by high glucose in NP cells was through PPARγ-dependent pathway.

Pramlintide regulation of extracellular matrix (ECM) and apoptosis through mitochondrial-dependent pathways in human nucleus pulposus cells

Pramlintide, an approved analog of amylin, is responsible for regulating the physiology of energy homeostasis. The goals of this study were to investigate the roles of pramlintide in the regulation of cell survival and matrix metabolism, and further explore their underlying mechanisms, in human nucleus pulposus (NP) cells. NP cells were treated with different concentrations of pramlintide in normoxic or hypoxic conditions. Cell viability, LAC concentration, calcium concentration, mitochondrial membrane potential (ΔΨm), MMPs proteins, and apoptotic related proteins were detected. The results indicate that pramlintide could improve NP cell proliferation, glycolytic activity, and the ECM synthesis under hypoxia, which is evident from the increased precipitation of proteoglycans; increased expression of AGG, Col2, and SOX9 proteins; and decreased expression of MMP3, MMP9, and MMP13 proteins, which are Ca²⁺-dependent enzymes. And, pramlintide could facilitate the survival of NP cells through mitochondrial-mediated, Bcl-2/caspase-3-dependent apoptosis. In addition, activation of AKT-AMPK/mTOR signaling pathway is also observed by the treatment. These findings demonstrate that pramlintide may play a pivotal role in reversing intervertebral disk degeneration and may relieve the impairment of ECM metabolism and NP cells survival through mitochondrial-dependent apoptotic signaling pathway, thus offering a novel potential pharmacological treatment strategy.

Detection of O-Linked-N-Acetylglucosamine Modification and Its Associated Enzymes in Human Degenerated Intervertebral Discs

Study Design

Human herniated discs were obtained from discectomy specimens for the immunohistochemical detection of O-GlcNAc and O-GlcNAcase (OGA)/O-GlcNAc transferase (OGT).

Purpose

This study aimed to quantify the extent of O-GlcNAcylation and its associated enzymes (OGT/OGA) in human degenerated intervertebral discs.

Overview of Literature

The O-GlcNAcylation of nuclear, cytoplasmic, and mitochondrial proteins as well as the effects of such post-translational modifications are currently the focus of extensive research. O-GlcNAcylation is believed to contribute to the etiology of chronic illnesses by acting as a nutrient and stress sensor in the cellular environment. Mature intervertebral disc cells are chondrocyte-like cells, and O-GlcNAc has been shown to promote chondrocyte apoptosis in vitro. We believe that O-GlcNAcylation is a key regulator of disc degeneration.

Methods

Fifty-six specimens were fixed for 24 hours in a 10% solution of neutral-buffered formaldehyde, dehydrated, and embedded in paraffin. Tissue slices (4-µm-thick) were used for hematoxylin-eosin staining and immunohistochemistry.

Results

We found that O-GlcNAcylation of cytoplasmic proteins was less than that of nuclear proteins in both single cells and cell clusters. Cytoplasmic O-GlcNAcylation occurs subsequent to nuclear O-GlcNAcylation and is directly proportional to disc degeneration. OGT and O-GlcNAc expression levels were identical in all specimens examined.

Conclusions

O-GlcNAc and OGA/OGT expression is shown to correlate for the first time with intervertebral disc cell degeneration. Increasing disc degeneration is associated with increasing O-GlcNAcylation in both nuclear and cytoplasmic proteins in human disc cells.

Risk Factors Analysis for Foot Drop Associated with Lumbar Disc Herniation: An Analysis of 236 Patients

OBJECTIVES

To identify the risk factors for foot drop in patients with lumbar disc herniation (LDH).

METHODS

Two hundred thirty-six patients who underwent surgery for LDH were retrospectively reviewed. Foot drop was defined as tibialis anterior muscle strength of lower than grade 4 by the manual muscle test. Possible risk factors, including demographic and radiographic parameters, were evaluated by multivariate logistic regression analysis.

RESULTS

Fifty-two patients (22.9%) suffered from foot drop. Multivariate logistic regression analysis revealed that diabetes mellitus, disc calcification, patients who had an acute episode or acute-on-chronic episode, and patients who presented with lateral recess or extraforaminal type of disc herniation were at greater risk of foot drop. Notably, patients who had a canal occupancy rate of more than 50% were at greater risk of foot drop compared with patients who had a canal occupy rate of less than 25%. With a 1.0-mm increase in anteroposterior diameter of the index spinal canal, the risk of developing foot drop decreased to 51.8% in these patients (P < 0.05).

CONCLUSIONS

The following factors may affect the development of foot drop in patients with LDH: 1) diabetes mellitus; 2) patients with an acute episode or acute-on-chronic episode; 3) patients with lateral recess or foraminal type of herniation; 4) disc calcification; 5) canal occupancy rate greater than 50%; and 6) the anteroposterior diameter of canal. Surgical treatments for patients with those risk factors should be implemented positively during the follow-up period to reduce possible adverse outcomes.

Investigation of the Effect of Diabetes on Radiculopathy Induced by Nucleus Pulposus Application to the DRG in a Spontaneously Diabetic Rat Model

STUDY DESIGN

A controlled, interventional animal study.

OBJECTIVE

The aim of this study was to evaluate the effect of diabetes mellitus (DM) on radiculopathy due to lumbar disc herniation (LDH), by investigating pain-related behavior and the expression of tumor necrosis factor-alpha (TNF-α) and growth-associated protein 43 (GAP43) in type 2 diabetic rats following application of nucleus pulposus (NP) to the dorsal root ganglion (DRG).

SUMMARY OF BACKGROUND DATA

Previous clinical studies suggested negative effects of DM on radiculopathy due to LDH, and that inflammation and nerve regeneration could interact with DM and radiculopathy.

METHODS

We applied autologous NP to the left L5 DRG of adult male Wistar rats and Goto-Kakizaki rats. Behavioral testing measured the mechanical withdrawal threshold of rats. We immunohistochemically evaluated the localization of ionized calcium-binding adapter molecule-1 (Iba-1), receptor of advanced glycation end products (RAGE), and TNF-α in DRGs. TNF-α and GAP43 expression levels in DRG were determined by quantitative real-time PCR and western blotting.

RESULTS

The mechanical withdrawal threshold significantly declined in the non-DM NP group compared with the non-DM sham group for 28 days, whereas the decline in threshold extended to 35 days in the DM NP group compared with the DM sham group. RAGE and TNF-α expression in DRGs was colocalized in Iba-1 positive cells. The non-DM NP rats had higher TNF-α protein expression levels versus the non-DM sham rats on day 7, and the DM NP group had higher levels versus the DM sham group on days 7 and 14. The non-DM NP group had higher GAP43 mRNA expression than the non-DM sham group for 28 days, while the DM NP group had a higher level than the DM sham group for 35 days.

CONCLUSION

DM prolongs the pain-related behavior caused by NP. The prolonged inflammation and nerve regeneration could elucidate the pathogenesis of continuous pain of radiculopathy initiated by LDH.

LEVEL OF EVIDENCE

N /A.

Protective effect of CDDO-ethyl amide against high-glucose-induced oxidative injury via the Nrf2/HO-1 pathway

BACKGROUND CONTEXT

Intervertebral disc degeneration (IDD) is the main cause of low back pain, and nucleus pulposus (NP) cell apoptosis is an important risk factor of IDD. However, the molecular mechanism of this disease remains unknown.

PURPOSE

To assess the potential protective effect of CDDO-ethyl amide (EA) against high-glucose-induced oxidative stress injury in NP cells and to investigate the mechanism of antioxidative effects and apoptotic inhibition.

STUDY DESIGN/SETTING

To find new molecule to inhibit intervertebral disc degeneration.

METHODS

Viability, reactive oxygen species (ROS) levels, and apoptosis were examined in NP cells. The protein expression levels of HO-1 and Nrf2 were measured through Western blot RESULTS: CDDO-EA elicited cytoprotective effects against NP cell apoptosis and ROS accumulation induced by high glucose. CDDO-EA treatment increased the HO-1 and Nrf2 expression abrogated by HO-1, Nrf2, and mitogen-activated protein kinase inhibitors.

CONCLUSIONS

The phosphorylation and nuclear translocation of Nrf2 are crucial for HO-1 overexpression induced by CDDO-EA, which is essential for the cytoprotection against high-glucose-induced oxidative stress in NP cells.