Serum lipid levels are positively correlated with lumbar disc herniation--a retrospective study of 790 Chinese patients

Lipid levels and low back pain risk: A two-sample mendelian randomization study

BACKGROUND

Previous observational studies have shown controversial results about the relationship between lipid levels and low back pain (LBP). Herein, we aimed to explore the potential causal relationship between lipid levels and LBP by using the mendelian randomization (MR) analysis.

METHODS

In this two-sample MR study, data were extracted from publicly available MRC Integrative Epidemiology Unit database. Three single-nucleotide polymorphisms (SNPs) of lipid levels [high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglycerides (TG)] and two SNPs of LBP risk (LBP and back pain) were retrieved and used as genetic instrumental variables. Inverse-variance weighted (IVW), weighted median, MR-Egger, robust adjusted profile score (MR-RAPS), and MR-PRESSO were used to examine the potential causal association between lipid levels and LBP.

RESULTS

IVW (fixed effect) estimation indicated that increased HDL-C level was negatively related to the odds of LBP for European populations. [odds ratio (OR) = 0.923, 95% confidence interval (CI): 0.857-0.993, P = 0.0323]. Similar results were also found in IVW (random effect) (OR = 0.923, 95% CI: 0.866-0.983, P = 0.0134), MR-Egger (OR = 0.858, 95%CI: 0.757-0.973, P = 0.0177), MR-RAPS (OR = 0.932, 95%CI: 0.871-0.997, P = 0.0419), and MR-PRESSO (OR = 0.933, 95%CI: 0.880-0.989, P = 0.0198) analyses. Whereas no causal link was observed between LDL-C/TG and LBP risk (P>0.05).

CONCLUSION

This two-sample MR study demonstrated a causal relationship between lipid levels and LBP risk. Further investigations are necessary to elucidate the causal association and specific underlying mechanisms by which lipid levels contribute to the development of LBP.

Low-Density Lipoprotein Cholesterol and Statin Usage Are Associated With Rates of Pseudarthrosis Following Single-Level Posterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate the relationships of low-density lipoprotein cholesterol and statin usage with pseudarthrosis following single-level posterior or transforaminal lumbar interbody fusion (PLIF/TLIF).

SUMMARY OF BACKGROUND DATA

Hypercholesterolemia can lead to atherosclerosis of the segmental arteries, which branch into vertebral bone through intervertebral foramina. According to the vascular hypothesis of disc disease, this can lead to ischemia of the lumbar discs and contribute to lumbar degenerative disease. Yet, little has been reported regarding the effects of cholesterol and statins on the outcomes of lumbar fusion surgery.

MATERIALS AND METHODS

TriNetX, a global federated research network, was retrospectively queried to identify 52,140 PLIF/TLIF patients between 2002 and 2021. Of these patients, 2137 had high cholesterol (≥130 mg/dL) and 906 had low cholesterol (≤55 mg/dL). Perioperatively, 18,275 patients used statins, while 33,415 patients did not. One-to-one propensity score matching for age, sex, race, and comorbidities was conducted to balance the analyzed cohorts. The incidence of pseudarthrosis was then assessed in the matched cohorts within the six-month, one-year, and two-year postoperative periods.

RESULTS

After propensity score matching, high-cholesterol patients had greater odds of developing pseudarthrosis six months [odds ratio (OR): 1.73, 95% confidence interval (CI): 1.28-2.33], one year (OR: 1.59, 95% confidence interval (CI): 1.20-2.10), and two years (OR: 1.57, 95% CI: 1.20-2.05) following a PLIF/TLIF procedure. Patients with statin usage had significantly lower odds of developing pseudarthrosis six months (OR: 0.74, 95% CI: 0.69-0.79), one year (OR: 0.76, 95% CI: 0.71-0.81), and two years (OR: 0.77, 95% CI: 0.72-0.81) following single-level PLIF/TLIF.

CONCLUSIONS

The findings suggest that patients with hypercholesterolemia have an increased risk of developing pseudarthrosis following PLIF/TLIF while statin use is associated with a decreased risk. The data presented may underscore an overlooked opportunity for perioperative optimization in lumbar fusion patients, warranting further investigation in this area.

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.

Lumbar disc herniation is an independent predictor of plaque burden in the patients with unstable angina

Objective

Assessing the impact of lumbar disc herniation (LDH) on the plaque burden of coronary atherosclerosis is our objective.

Methods

In this study, a total of 212 patients (age 46-80 years) with unstable angina (UA) who underwent coronary angiography (CAG) in our hospital from January 2018 to July 2022 due to UA were included. Patients were divided into LDH group (n = 106) and no LDH group (n = 106). Gensini scores were calculated to assess the plaque burden of coronary. Logistic analysis was used to examine potential risk variables linked to the Gensini score. The association between lumbar disc lesions grading and coronary plaque burden was analysed by Spearman's correlation test. LDH patients with higher plaque burden (n = 56) were further divided into evolocumab treatment group (n = 28) and conventional treatment group (n = 28). Cox regression analysis were performed.

Results

Patients with LDH had higher Gensini scores (P < 0.01) and triglyceride (TG) levels (P = 0.04), but HDL-C (P = 0.01) levels were lower. LDH was found to be an independent risk factor for higher Gensini scores (OR = 2.38, P < 0.01) by logistic analysis. The Spearman's correlation test suggested that the degree of lumbar disc lesions was related to the Gensini score and the level of blood lipid. Cox regression analysis showed that evolocumab treatment could significantly reduce the composite MACE events (cardiac death, nonfatal myocardial infarction, nonfatal stroke, and readmission due to angina) (HR = 0.26, P = 0.04) in higher coronary plaque burden patients.

Conclusion

LDH is an independent risk factor for the higher coronary plaque burden. Evolocumab treatment significantly reduced the occurrence of cardiovascular events in LDH patients with higher plaque burden. Additionally, our data indicate that LDH is associated with increased blood lipid, which may contribute to the development of plaque burden.

The Effect of Hyperlipidemia as a Risk Factor on Postoperative Complications in Patients Undergoing Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To analyze the effect of hyperlipidemia (HLD) on postoperative complications in patients who underwent anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

ACDF represents the standard procedure performed for focal anterior nerve root or spinal cord compression with low complication rates. HLD is well known as a risk factor for major complications after vascular and transplant surgery, and orthopedic surgery. To date, there have been no studies on HLD as a risk factor for cervical spine surgery.

PATIENTS AND METHODS

Patients who underwent ACDF from 2010 through quarter 3 of 2020 were enrolled using the MSpine subset of the PearlDiver Patient Record Database. The patients were divided into single-level ACDF and multilevel ACDF groups. In addition, each group was divided into subgroups according to the presence or absence of HLD. The incidence of surgical and medical complications was queried using relevant International Classification of Disease and Current Procedural Terminology codes. Charlson Comorbidity Index was used as a broad measure of comorbidity. χ 2 analysis, with populations matched for age, sex, and Charlson Comorbidity Index, was performed.

RESULTS

A total of 24,936 patients who underwent single-level ACDF and 26,921 patients who underwent multilevel ACDF were included. In the multilevel ACDF group, wound complications were significantly higher in the patients with HLD. Among medical complications, myocardial infarction, renal failure, and urinary tract infection/urinary incontinence were significantly higher in the patients with HLD in both groups. Revision surgery and readmission were significantly higher in the patients with HLD who underwent multilevel ACDF.

CONCLUSIONS

In patients who underwent ACDF, several surgical and medical complications were found to be higher in patients with HLD than in patients without HLD. Preoperative serum lipid concentration levels and management of HLD should be considered during preoperative planning to prevent postoperative complications in patients undergoing ACDF.

Genetically predicted triglycerides mediate the relationship between type 2 diabetes Mellitus and intervertebral disc degeneration

BACKGROUND

To validate the causal relationship between type 2 diabetes mellitus (T2DM) and intervertebral disc degeneration (IVDD) and to identify and quantify the role of triglycerides (TGs) as potential mediators.

METHODS

A two-sample Mendelian randomization (MR) analyses of T2DM (61,714 cases and 1178 controls) and IVDD (20,001 cases and 164,682 controls) was performed using genome-wide association studies (GWAS). Moreover, two-step MR was employed to quantify the proportionate impact of TG-mediated T2DM on IVDD.

RESULTS

MR analysis showed that T2DM increased IVDD risk (OR: 1.0466, 95% CI 1.0049-1.0899, P = 0.0278). Reverse MR analyses demonstrated that IVDD does not affect T2DM risk (P = 0.1393). The proportion of T2DM mediated through TG was 11.4% (95% CI 5.5%-17.4%).

CONCLUSION

This work further validates the causality between T2DM and IVDD, with a part of the effect mediated by TG, but the greatest impacts of T2DM on IVDD remain unknown. Further studies are needed to identify other potential mediators.

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.

Roles of pyroptosis in intervertebral disc degeneration

Intervertebral disc degeneration (IDD), the key pathological process in low back pain, is characterized by chronic inflammation and progressive cell death. Pyroptosis is a type of pro-inflammatory programmed necrosis mediated by inflammasomes that is dependent on the gasdermin family of proteins. An in-depth study of the pathological mechanisms of IDD has revealed that pyroptosis plays an important role in its occurrence and development. The molecular characteristics and activation signaling mechanisms of pyroptosis are reviewed in this paper. Moreover, the specific roles of pyroptosis in IDD pathology are outlined and various targeted drugs for its treatment are highlighted.

MicroRNA-155 suppressed cholesterol-induced matrix degradation, pyroptosis and apoptosis by targeting RORα in nucleus pulposus cells

Intervertebral disc degeneration (IDD) is associated with low back pain, yet its inherent mechanism remains obscure. Hypercholesteremia was regarded as a risk factor for IDD, and our previous study showed that cholesterol accumulation could elicit matrix degradation in the nucleus pulposus (NP). MicroRNA-155 (miR-155) was substantiated as protective in IDD, but its role in cholesterol-induced IDD was unclear. The present study investigated whether miR-155 could mediate cholesterol-related IDD and its internal mechanisms. In vivo experiments revealed high-fat diet-induced hypercholesteremia in wild-type (WT) mice along with the occurrence of IDD, whereas Rm155LG transgenic mice showed milder NP degeneration, as evidenced by Safranin O-fast green (SF) staining and immunohistochemistry (IHC). Meanwhile, IHC showed that NLRP3 and Bax expression was also suppressed in Rm155LG mice. In vitro studies using Western blotting (WB) and immunofluorescence (IF) confirmed that the miR-155 mimic could alleviate cholesterol-induced matrix degradation, apoptosis and pyroptosis in NP. Moreover, RORα was upregulated in severely degenerated NP compared to mild IDD. It was also noted that RORα was suppressed in Rm155LG mice. In this study, we demonstrated that miR-155 could target RORα and that inhibition of RORα could prevent cholesterol-induced matrix degradation, apoptosis, and pyroptosis in NP, indicating the protective effect of miR-155 in cholesterol-induced IDD by targeting RORα.

Genetics of Intervertebral Disc Degeneration

PURPOSE OF REVIEW

Intervertebral disc degeneration is a contributor to chronic back pain. While a part of the natural aging process, early or rapid intervertebral disc degeneration is highly heritable. In this review, we summarize recent progress towards unraveling the genetics associated with this degenerative process.

RECENT FINDINGS

Use of large cohorts of patient data to conduct genome-wide association studies (GWAS) for intervertebral disc disease, and to lesser extent for aspects of this process, such as disc height, has resulted in a large increase in our understanding of the genetic etiology. Genetic correlation suggests that intervertebral disc disease is pleiotropic with risk factors for other diseases such as osteoporosis. The use of Mendelian Randomization is slowly establishing what are the causal relationships between intervertebral disc disease and factors previously correlated with this disease. The results from these human genetic studies highlight the complex nature of this disease and have the potential to lead to improved clinical management of intervertebral disc disease. Much additional work should now be focused on characterizing the causative relationship various co-morbid conditions have with intervertebral disc degeneration and on finding interventions to slow or halt this disease.

Nutrient metabolism of the nucleus pulposus: A literature review

Cells take in, consume, and synthesize nutrients for numerous physiological functions. This includes not only energy production but also macromolecule biosynthesis, which will further influence cellular signaling, redox homeostasis, and cell fate commitment. Therefore, alteration in cellular nutrient metabolism is associated with pathological conditions. Intervertebral discs, particularly the nucleus pulposus (NP), are avascular and exhibit unique metabolic preferences. Clinical and preclinical studies have indicated a correlation between intervertebral degeneration (IDD) and systemic metabolic diseases such as diabetes, obesity, and dyslipidemia. However, a lack of understanding of the nutrient metabolism of NP cells is masking the underlying mechanism. Indeed, although previous studies indicated that glucose metabolism is essential for NP cells, the downstream metabolic pathways remain unknown, and the potential role of other nutrients, like amino acids and lipids, is understudied. In this literature review, we summarize the current understanding of nutrient metabolism in NP cells and discuss other potential metabolic pathways by referring to a human NP transcriptomic dataset deposited to the Gene Expression Omnibus, which can provide us hints for future studies of nutrient metabolism in NP cells and novel therapies for IDD.

Association between cardiovascular risk factors and degenerative disc disease of the thoracolumbar spine in the general population: results from the KORA MRI Study

BACKGROUND

Little is known about the associations between cardiovascular risk factors (CRF) and disc degeneration (DD).

PURPOSE

To evaluate the potential association between CRFs and intervertebral DD in a population-based sample.

METHODS

A total of 400 participants from the community-based KORA-study were assessed in terms of CRFs, specifically obesity, hypertension, diabetes, elevated LDL-c, low HDL-c, elevated triglycerides, smoking status, and alcohol consumption. The patients additionally underwent whole-body magnetic resonance imaging (MRI) using T2-weighted single-shot fast-spin-echo and T1 dual-echo gradient-echo Dixon pulse sequences. Thoracic and lumbar DD were assessed using the Pfirrmann score and for the presence of disc bulging/protrusion. Cross-sectional associations between CRFs and MR-based Pfirrmann score were then analyzed.

RESULTS

A total of 385 individuals (58.2% men; mean age 56.3 ± 9.2 years) were included. Prevalence of DD was 76.4%. Older age (β = 0.18; 95% CI 0.12-0.25; P < 0.001) and higher body mass index (BMI) (β = 0.19; 95% CI 0.06-0.30; P = 0.003) were significantly associated with DD of the thoracolumbar spine. Diabetes was significantly associated with DD at T7/8 (P = 0.029) and L3/4 (P = 0.017). Hypertension correlated significantly with DD in univariate analysis, but the association did not persist using multivariate analysis (β = 0.53; 95% CI -0.74 to 1.81; P = 0.41). None of the other CRFs (P ≥ 0.11) were associated with advanced DD. Disc bulging was independently associated with hypertension (β = 0.47; 95% CI 0.27-0.81; P = 0.01).

CONCLUSION

A significant independent association exists between age, BMI, and intervertebral DD. In contrast, there is no significant association between cardiovascular risk factors and DD. Providing strong evidence that the pathologic process undergirding DD is mechanical, rather than microvascular, in nature.

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.

Low Back Pain Physiotherapy: Does Expectation Really Influence Outcome?

Objectives: Low Back Pain (LBP) is prevalent in most people of working age. The morbidity it causes cannot be taken lightly, as is its economic burden. Physiotherapy has long been prescribed to LBP patients, but treatment outcome measurements, along with the factors influencing it, have not been widely evaluated. In this study, we aim to assess the correlation between patient’s expectation and LBP physical therapy outcome. Methods: This was a cross sectional study conducted at physical rehabilitation outpatient clinic in September-December 2019. Participants were patients with LBP who were treated with physical therapy. One series of physical therapy consists of 5 sessions of modality only or modality with exercise therapy; one patient underwent 2 sessions per week. Oswestry disability index (ODI) score was used to evaluate treatment outcome and Stanford Expectation of Treatment Scale score was used to evaluate patient’s expectation. Data was collected twice, before and after 1 series of therapy. Results: There were 91 participants included in this study, most of whom were female. Most patients reported a significant decrease in ODI score, irrespective of the LBP chronicity or nutritional status. However, patients who received a combination of physical exercises and modalities reported lower after therapy ODI than those who only received modalities (p=0.009). No correlation was found between positive (p=0.567) or negative (p=0.910) expectations with ODI improvement. Conclusion: Our study did not find any correlation between positive or negative expectations towards ODI score improvement. Keywords: Low back pain; Physical therapy; Treatment outcome; Patient expectation; ODI score

Cholesterol Induces Pyroptosis and Matrix Degradation via mSREBP1-Driven Endoplasmic Reticulum Stress in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is closely associated with low back pain, but its underlying mechanism remains unclear. Cholesterol is an essential nutrient in mammalian cells. Alterations in cholesterol levels lead to impairments in cell physiology, such as cell proliferation and signal transduction. Previous clinical studies demonstrated that hypercholesterolemia could be a potential risk factor for IDD, but how cholesterol induces IDD remains unknown. The current study aimed to explore the regulatory role of cholesterol in IDD development and the potential underlying mechanisms. It was found that different forms of cholesterol levels were elevated in degenerative nucleus pulposus (NP) tissues in both humans and Sprague–Dawley rats. Rats fed a high cholesterol diet (HCD) exhibited degenerative features in the lumbar intervertebral disc compared with those fed a standard diet. Interestingly, this effect could be abolished by cholesterol-lowering drug atorvastatin. In NP cells treated with TNF-α and IL-1β, a significantly higher level of cholesterol was observed. These results suggested a pivotal role of cholesterol in the progression of IDD. We also observed accelerated pyroptosis in NP cells and extracellular matrix (ECM) degradation in the rat NP cells treated with exogenous cholesterol. We further demonstrated that endoplasmic reticulum stress was responsible for cholesterol-induced pyroptosis and ECM degradation. Moreover, RNA-seq analysis revealed that the mature form of SREBP1 (mSREBP1), an important regulator of lipid metabolism, is involved in regulating endoplasmic reticulum stress in knockdown experiments. In conclusion, this study demonstrated that cholesterol could induce pyroptosis in NP cells and ECM degradation by activating endoplasmic reticulum stress through stimulating mSREBP1 in IDD.

Impact of dyslipidemia on the severity of symptomatic lumbar spine degeneration: A retrospective clinical study

BACKGROUND

Lumbar intervertebral disc degeneration (IVDD) is an important cause of low back pain or sciatica, and metabolic factors play an important role. However, little is known about the relationship of dyslipidemia to the risk of intervertebral disc degeneration (IVDD). This study aimed to assess the impact of serum lipid levels on the severity of lumbar disc degeneration and to investigate its association with endplate inflammation.

METHODS

We conducted a case retrospective study in which a total of 302 hospitalized Chinese patients were recruited, of whom 188 (112 males and 76 females; mean age: 51.66 years) were without underlying disease, while the remaining 114 patients (51 males and 63 females; mean age: 62.75 years) had underlying diseases. We examined fasting serum lipid levels for total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Magnetic resonance imaging (MRI) was used to determine endplate inflammation. Pfirrmann grading and Weishaupt grading were used to evaluate the severity of intervertebral disc degeneration and facet joint degeneration, respectively.

RESULTS

There was no difference in age, gender, and general BMI between the two groups (P > 0.05), but there were significantly high levels in TC, LDL-C, and LDL-C/HDL-C (P = 0.04, P = 0.013, P = 0.01, respectively). TG and HDL-C showed no significant difference (P = 0.064, P = 0.336, respectively). The multivariate logistic regression model showed that age was a risk factor for the occurrence of endplate inflammation. In the group without underlying diseases, age, but not other indicators, was a risk factor for the occurrence of endplate inflammation (P < 0.01), In the group with underlying diseases, none of the patient indicators was directly related to the occurrence of endplate inflammation (P > 0.05). A nonlinear machine learning model was used to measure the contribution of each factor to the disease outcome and to analyze the effect between the top three contributing factors and the outcome variables. In patients without underlying diseases, the top three factors contributing to the severity grading of intervertebral disc degeneration were age (32.9%), high-density lipoproteins (20.7%), and triglycerides (11.8%). For the severity grading of facet joint degeneration, the top three contributing factors were age (27.7%), high-density lipoproteins (19.4%), and triglycerides (14.6%). For patients with underlying diseases, the top three factors contributing to intervertebral disc degeneration were age (25.4%), BMI (15.3%), and low-density lipoprotein/high-density lipoprotein ratio (13.9%). In terms of degree classification for facet joint degeneration, the top three contributing factors were age (17.5%), BMI (17.2%), and total cholesterol (16.7%).

CONCLUSION

This study shows that age, high-density lipoprotein, and triglycerides affect the degree of degeneration in patients with symptomatic lumbar degeneration without underlying diseases. Age and BMI are two major factors affecting the severity of degeneration in patients with underlying diseases, and dyslipidemia is a secondary factor. However, there is no clear association between dyslipidemia and the occurrence of endplate inflammation in either group.

Prevalence and Risk Factors Associated with Low Back Pain in the Saudi Adult Community: A Cross-Sectional Study

Worldwide, low back pain is common and linked with many risk factors. There is a lack of studies in the Saudi Arabian community on low back pain prevalence and risk factors. Therefore, the present research will investigate the prevalence of low back pain in the middle-aged and elderly community population and examine the risk factors contributing to low back pain in Saudi Arabia. The present paper is a cross-sectional study of the community living in Riyadh and the surrounding areas in Saudi Arabia. Data were collected between October 2019 and April 2020 via trained research assistants. A total of 276 participants were included in the analysis. The prevalence of low back pain was 27.9% (n = 77) among the participants included in this study. All participants reported low back pain severity with a mean of 4.35 ± 2.19 on the pain rating scale. Older age, arthritis, hypertension, anemia, osteoporosis, and a history of fractures were all associated with having LBP. Low back pain is highly prevalent in the Saudi community adult population living in Riyadh and its surrounding areas. More than a fourth of the sample reported experiencing back pain. The study outlines several modifiable risk factors (BMI, education, employment status, marital status, and smoking status) and unmodifiable risk factors (arthritis, hypertension, anemia, osteoporosis, and a history of fractures) associated with low back pain in the study sample.

Serum apolipoprotein B/apolipoprotein A1 ratio in relation to intervertebral disk herniation: a cross-sectional frequency-matched case-control study

Study design

This was a cross-sectional frequency-matched case–control study.

Background and aim

The serum lipid profile of lipoprotein(a) [Lp(a)] level and apolipoprotein B/apolipoprotein A1 ratio (Apo B/Apo A1) ratio were found to be more representative for serum lipid level and were recognized as the independent risk factors for various diseases. Although the blood levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were found to be associated with symptomatic intervertebral disk herniation (IDH), no studies to date have evaluated the association of Apo AI, Apo B, Lp(a), and Apo B/Apo AI levels with symptomatic IDH. This study aimed to assess the link between blood lipid levels and symptomatic IDH.

Method

The study included 1839 Chinese patients. Of these, 918 patients were diagnosed with IDH and enrolled in the experimental group. A control group of 921 patients underwent a physical examination during the same period. The serum lipid levels of TC, TG, LDL-C, HDL-C, Lp(a), Apo B, and Apo B/Apo AI were examined and analyzed. The control group comprised randomly selected patients who met the baseline levels of the aforementioned lipid molecules.

Results

Patients with IDH exhibited significantly higher TC, TG, LDL, Apo B, and Lp(a) levels than controls. The percentage of high TC, high TG, high LDL, high Apo B, and high Lp(a) were obviously higher in the IDH group than in the control group. However, hyperlipidemia had no relationship with the degenerated segment of the IDH (P = 0.201). The odds ratio (OR) for the incidence of IDH with elevated levels of LDL-C, TC, TG, Lp(a), Apo B, and Apo B/Apo AI was 1.583, 1.74, 1.62, 1.58, 1.49, and 1.39, respectively. The correlation analysis revealed the correlation between elevated LDL-C, TC, TG, Apo B, Lp(a), and incidence of IDH was significant (R²_LDL = 0.017; R²_TC = 0.004; R²_TG = 0.015; R²_{Apo B} = 0.004; R²_Lp(a) = 0.021) (P < 0.05).

Conclusion

This study suggested that elevated levels of serum TC, TG, LDL, Apo B, Lp(a), and Apo B/Apo AI were associated with a higher risk of IDH. This study provided useful information to identify a population that might be at risk of developing IDH based on elevated lipid levels.

Inverse Agonist of Retinoid-Related Orphan Receptor-Alpha Prevents Apoptosis and Degeneration in Nucleus Pulposus Cells via Upregulation of YAP

Intervertebral disc degenerative disease (IDD) is the most common degenerative spine disease, which leads to chronic low back pain and symptoms in the lower extremities. In this study, we found that RORα, a member of the retinoid-related orphan receptor family, is significantly elevated in nucleus pulposus tissue in IDD patients. The elevation of RORα is associated with increased apoptosis of nucleus pulposus (NP) cells. Therefore, we applicated a well-established inverse agonist of RORα, SR3335, to investigate its role in regulating NP cell metabolism and apoptosis. To further investigate the mechanism that SR3335 regulates the pathogenesis of IDD in vitro, tumor necrosis factor alpha (TNF-α) stimulation was used in human NP cells to mimic the hostile environment that leads to degeneration. We found that SR3335 treatment reversed the trend of increased apoptosis in NP cells induced by TNF-α treatment. Next, TNF-α treatment upregulated the expression of type II collagen and aggrecan and downregulated MMP13 (matrix-degrading enzyme matrix metalloproteinase 13) and ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs 4). However, these effects were reversed after SR3335 treatment. Furthermore, we find that SR3335 mediated the effect in NP cells by regulating the YAP signaling pathway, especially by affecting the phosphorylation state of YAP. In conclusion, the reduction of matrix degradation enzymes and apoptosis upon SR3335 treatment suggests that SR3335 is a promising drug in reversing the deleterious microenvironment in IDD patients.

Drp1-mediated mitochondrial fission is involved in oxidized low-density lipoprotein-induced AF cella poptosis

This study aimed to assess the negative effect of oxidized low-density lipoprotein (oxLDL) on annulus fibrosus (AF) cells and decipher the mechanism of action of the process. After treating AF cells with various concentrations (0, 25, 50, 100, and 200 μg/mL) of oxLDL for 24 and 48 hours, their viability was evaluated using cell counting kit-8 and live/dead staining. The percentage of AF cell death was determined with Annexin V/propidium iodide apoptosis staining. The expression of proteins related to the mitochondrial apoptosis pathway was determined using Western blot. Additionally, mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) were assessed with JC-1 staining and dichlorodihydrofluorescein diacetate ormitoSOX probes, respectively. Mitochondrial morphology was observed with a transmission electron microscope. After treatment with oxLDL, AF cell viability decreased, pro-apoptosis proteins (such as Bax, cleaved caspase-9, and cleaved caspase-3) increased, and anti-apoptosis proteins (Bcl-2) declined. Excessive ROS and diminished MMP were also detected during this process, as were enhanced mitochondrial fission and augmented Drp1 expression. Furthermore, knocking down the expression of Drp1 rescued oxLDL-induced AF cell death. Collectively, these results suggest that oxLDL induces AF cell death through a mitochondria-related pathway. Enhanced mitochondrial fission was involved in oxLDL-induced AF cell death. Targeting Drp1, a target for regulating the process of mitochondrial fission, may be a feasible strategy for preventing intervertebral disc degeneration in hyperlipidemia.

Correlation between thoracolumbar disc degeneration and anatomical spinopelvic parameters in supine position on MRI

Objective

This study aims to investigate the correlation between spinopelvic parameters in supine position (pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL)), disc degeneration and herniation of the thoracolumbar spine, as well as cardiovascular risk factors and back pain in a southern German cohort from the general population.

Methods

This study is a cross-sectional, case–control study drawn from a prospective cohort of the “Cooperative Health Research in the Region of Augsburg/Kooperative Gesundheitsforschung in der Region Augsburg” study (KORA). In total, 374 participants (mean age 56.4 ± 9.2 years; 57.8% male) from the whole-body MRI cohort (FF4) were included. All participants underwent a standardized whole-body MRI on which disc degeneration of the thoracic and lumbar spine was evaluated using a sequence adapted Pfirrmann score. PI, PT, SS and LL were measured according to the description in the literature, using sagittal imaging. Furthermore, disc bulging and protrusion were assessed. Correlations were estimated by logistic regression models providing odds ratios.

Results

Mean PI was 54.0° ± 11.1°, PT 13.0° ± 5.8°, SS 40.2° ± 8.8° and LL 36.2° ± 9.6°. SS was greater in men (p<0.05) and lumbar lordosis in women (p<0.001). PT increased by 0.09° per age-year with rising age. Age was not associated with PI, SS and LL. Neither BMI, hypertension, cholesterol, lipid levels, nor physical activity were associated with PI, PT, SS or LL. Diabetes mellitus negatively correlated with SS (β = -4.19; 95%CI -7.31–1.06, p<0.01). Smaller spinopelvic parameters (PI, SS and LL) where significantly (p<0.05) correlated with an increased frequency of disc bulging, as well as a local clustering in the lumbar, but not the thoracic spine.

Conclusion

In conclusion, spinopelvic parameters, measured in supine position, are significantly correlated with disc bulging alone; there is no significant correlation between supine spinopelvic parameters and disc degeneration, back pain or cardiovascular risk factors.

The role of oxidation of low-density lipids in pathogenesis of osteoarthritis: A narrative review

Osteoarthritis (OA) is a chronic joint disorder that causes degeneration of cartilage, synovial inflammation, and formation of osteophytes. Aging, obesity, and sex are considered the main risk factors of OA. Recent studies have suggested that metabolic syndrome (MetS) disorders, such as hypertension, hyperlipidemia, diabetes mellitus, and obesity, may be involved in the pathogenesis and progression of OA. MetS disorders are common diseases that also result in atherosclerosis. Researchers believe that OA and atherosclerosis have underlying similar molecular mechanisms because the prevalence of both diseases increases with age. Oxidation of low-density lipoprotein (ox-LDL) is believed to play a role in the pathogenesis of atherosclerosis. Recent reports have shown that ox-LDL and low-density lipoprotein receptor 1 (LOX-1) are involved in the pathogenesis of OA. The purpose of this narrative review is to summarize the current understanding of the role of the LOX-1/ox-LDL system in the pathogenesis of OA and to reveal common underlying molecular pathways that are shared by MetS in OA and the LOX-1/ox-LDL system.

The impact and distinction of 'lipid healthy but obese' and 'lipid abnormal but not obese' phenotypes on lumbar disc degeneration in Chinese

Background

Lipid abnormality and obesity have been proposed to be associated with lumbar disc degeneration, but little is known about the effect of ‘lipid healthy but obese’ (LH-O) and ‘lipid abnormal but not obese’ (LA-NO) phenotypes on lumbar disc degeneration in Chinese. The study aims to determine the impact and distinction of LH-O and LA-NO phenotypes on lumbar disc degeneration in Chinese, and to identify the association of related factors with risk of lumbar disc degeneration.

Methods

A total of 678 individuals were included with lumbar magnetic resonance imaging, serum lipid levels and anthropometric measurements. Obesity was defined on the basis of body mass index or waist to hip ratio (WHR). Pfirrmann score and Weishaupt’s scale were utilized to assess the degree of disc degeneration and facet joint degeneration.

Results

The incidence of the LH-O and LA-NO phenotypes were 11.4% and 18.1%, respectively. LA-NO phenotype demonstrates a high incidence for disc degeneration (P < 0.05), while LH-O phenotype confers a severe disc degeneration grade (P < 0.05). No statistical difference in the percentage of severe facet joint degeneration grade in each group (P > 0.05). Elevated triglycerides and greater WHR may be the risk factors for lumbar disc degeneration in Chinese.

Conclusion

LH-O and LA-NO phenotypes are common with different status of disc degeneration in Chinese. Elevated triglycerides and abdominal obesity appear to play crucial roles in the development of lumbar disc degeneration.

The Influence of Comorbidities on Reoperations Following Primary Surgery of Lumbar Degenerative Diseases : A Nationwide Population-Based Retrospective Cohort Study from 2009-2016

Objective

Spinal degeneration is a progressive disease, worsening over time. Lumbar degenerative disease (LDD) is a major spinal disease in elderly patients. Surgical treatment is considered for medically intractable patients with LDD and reoperation after primary surgery is not uncommon. The surgical outcome is occasionally unpredictable because of comorbidities. In the present study, the relationship between comorbidities and the incidence of reoperation for LDD over time was determined.

Methods

The claims data of the health insurance national database were used to identify a cohort of patients who underwent spinal surgery for LDD in 2009. The patients were followed up until 2016. Medical comorbidity was assessed according to the Charlson comorbidity index (CCI). Cox proportional hazard regression modeling was used to identify significant differences in sex, surgery, age, causative disease, and comorbidity.

Results

The study cohort included 78241 patients; 10328 patients (13.2%) underwent reoperation during the observation period. The reoperation rate was statistically higher (p<0.01) in males, patients 55–74 years and 65–74 years of age, and patients with decompression or discectomy. Significant association was found between increasing reoperation rate and CCI score (p<0.01). Based on multivariate analysis of comorbidities, the significantly higher reoperation rates were observed in patients with peripheral vascular disease, pulmonary lung disease, peptic ulcer, diabetes, and diabetes complications (p<0.01).

Conclusion

The study results indicate the reoperation rate for LDD is associated with patient comorbidities. The comorbidities identified in this study could be helpful in future LDD studies.

Transcriptome signatures reveal candidate key genes in the whole blood of patients with lumbar disc prolapse

The present study aimed to investigate differentially expressed genes (DEGs) in whole blood (WB) obtained from patients with lumbar disc prolapse (LDP) and healthy volunteers. A total of 8 patients with LDP and 8 healthy volunteers were recruited. An Agilent SurePrint G3 human gene expression microarray 8×60 K was used to perform the microarray analyses. R was employed to identify DEGs, which were then subjected to bioinformatics analysis, including a Gene Ontology (GO) analysis, Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis and protein-protein interaction (PPI) network analysis. DEGs in the degenerative annulus fibrosis (AF) and nucleus pulposus (NP) compared with non-degenerative tissues were also identified based on microarray data and the intersections of the three were assessed. Furthermore, reverse transcription-quantitative (RT-q)PCR was performed to confirm the aberrant expression levels of selected DEGs in the WB of all subjects. A total of 161 DEGs between LDP patients and the healthy controls were identified (128 upregulated and 33 downregulated). These DEGs were enriched in 293 biological process, 36 cellular component and 21 molecular function GO terms, as well as in 24 KEGG pathways. The PPI network contained 4 submodules, and Toll-like receptor 4 had the highest degree centrality. A total of 22 DEGs were common to the three groups of DEGs. The RT-qPCR assay confirmed that the expression levels of cytochrome P450 family 27 subfamily A member 1, superoxide dismutase 2, protein disulfide isomerase family A member 4, FKBP prolyl isomerase 11 and ectonucleotide pyrophosphatase/phosphodiesterase 4 were significantly different between the patient group and the volunteer group. In conclusion, several genes were identified as potential biomarkers in WB that should be further explored in future studies to determine their potential application in the clinical treatment and diagnosis of LDP, and the present bioinformatics analysis revealed several GO terms, KEGG pathways and submodules of the PPI network that may be involved in LDP, although the exact mechanisms remain elusive.

Effect of hyperlipidaemia to accelerate intervertebral disc degeneration in the injured rat caudal disc model

BACKGROUND

Dyslipidaemia is a well-known risk factor for the development of atherosclerosis, however, little is known about the effect of dyslipidaemia on intervertebral disc degeneration (IVDD). Thus, the purpose of this study is to investigate the relationship between dyslipidaemia and IVDD, and to identify the possible mechanism by which dyslipidaemia aggravates the degeneration of intervertebral discs.

METHODS

Hyperlipidaemia rats were induced, thirty male Wistar rats were randomly divided into two groups: normal chow diet control group (CON) and high-fat diet group (HFD) for 8 weeks. And then, a rat disc degeneration model was established, rats were divided into three experimental groups: the normal chow diet + sham surgery group (CON-Sham); the normal chow diet + needle puncture group (CON-NP); and the high-fat diet + needle puncture group (HFD-NP), all rats were continually fed with normal chow diet or HFD 8 weeks. At the end of the experiment, the discs were harvested and histomorphological analysis, immunohistochemistry staining, real-time PCR and western blot were performed for all groups.

RESULTS

The degenerative histological score of disc in the HFD-NP group was significantly higher than the CON-NP group. Immunohistochemical analysis revealed remarkable reductions in aggrecan and collagen type II expressions, and significant increases in IL-1β, TNF-α, MMP-13, HIF-1α and P65 expression in the HFD-NP group. RT-PCR and western blot analysis showed that the mRNA levels and protein expressions of MMP-13 and TIMP-1 were higher in the HFD-NP group.

CONCLUSIONS

Hyperlipidaemia resulted in an exaggerated degenerative changes and altered expression and transcription of the degeneration-associated molecules in the rat disc tissue. These results raise the possibility that hyperlipidaemia may accelerate the progression of disc degeneration.

Trans-Ethnic Polygenic Analysis Supports Genetic Overlaps of Lumbar Disc Degeneration With Height, Body Mass Index, and Bone Mineral Density

Lumbar disc degeneration (LDD) is age-related break-down in the fibrocartilaginous joints between lumbar vertebrae. It is a major cause of low back pain and is conventionally assessed by magnetic resonance imaging (MRI). Like most other complex traits, LDD is likely polygenic and influenced by both genetic and environmental factors. However, genome-wide association studies (GWASs) of LDD have uncovered few susceptibility loci due to the limited sample size. Previous epidemiology studies of LDD also reported multiple heritable risk factors, including height, body mass index (BMI), bone mineral density (BMD), lipid levels, etc. Genetics can help elucidate causality between traits and suggest loci with pleiotropic effects. One such approach is polygenic score (PGS) which summarizes the effect of multiple variants by the summation of alleles weighted by estimated effects from GWAS. To investigate genetic overlaps of LDD and related heritable risk factors, we calculated the PGS of height, BMI, BMD and lipid levels in a Chinese population-based cohort with spine MRI examination and a Japanese case-control cohort of lumbar disc herniation (LDH) requiring surgery. Because most large-scale GWASs were done in European populations, PGS of corresponding traits were created using weights from European GWASs. We calibrated their prediction performance in independent Chinese samples, then tested associations with MRI-derived LDD scores and LDH affection status. The PGS of height, BMI, BMD and lipid levels were strongly associated with respective phenotypes in Chinese, but phenotype variances explained were lower than in Europeans which would reduce the power to detect genetic overlaps. Despite of this, the PGS of BMI and lumbar spine BMD were significantly associated with LDD scores; and the PGS of height was associated with the increased the liability of LDH. Furthermore, linkage disequilibrium score regression suggested that, osteoarthritis, another degenerative disorder that shares common features with LDD, also showed genetic correlations with height, BMI and BMD. The findings suggest a common key contribution of biomechanical stress to the pathogenesis of LDD and will direct the future search for pleiotropic genes.

Possible involvement of the oxLDL/LOX-1 system in the pathogenesis and progression of human intervertebral disc degeneration or herniation

Epidemiological studies have concluded that hyperlipidemia and atherosclerosis were related to intervertebral disc degeneration (IVDD). The presence of oxidized low density lipoprotein (ox-LDL) and the expression of lectin-like oxidized low density lipoprotein receptor 1 (LOX-1) have not been explored in this tissue. In this study, we investigated the presence of ox-LDL and the expression of its receptor LOX-1 in non-degenerated, degenerated or herniated human intervertebral discs (IVDs). The expression of LOX-1 and matrix metalloproteinase 3 (MMP3) were studied after incubating nucleus pulposus cells (NPCs) with ox-LDL. The presence of ox-LDL and LOX-1 was positively related with the extent of IVDD in nucleus pulposus (NP), end-plate cartilage and outer annulus fibrous, but not with the extent of degeneration of inter annulus fibrous. Ox-LDL significantly reduced the viability of human NPCs in a dose and time-dependent manner, and increased the expression of MMP3 induced by LOX-1. Pretreatment with anti-human LOX-1 monoclonal antibody reversed these effects. Ox-LDL, principally mediated by LOX-1, enhanced MMP3 production in NPCs through the NF-κB signaling pathway. In conclusion, increased accumulation of ox-LDL and LOX-1 in IVDs indicates a specific role of the receptor-ligand interaction in degeneration or herniation of IVDs.

Is there a relationship between blood lipids and lumbar disc herniation in young Turkish adults?

INTRODUCTION

Atherosclerosis might diminish the nutrient supply to intervertebral discs (IVD), leading to disc herniation. Therefore, there is interest in determining the possible association between the blood lipid profile and lumbar disc herniation (LDH). We aimed to evaluate the association between blood lipids and LDH in a homogeneous group of patients, controlling for age- and sex-specific effects.

MATERIAL AND METHODS

This is a case-control study which consisted of 100 individuals (mean age: 41.25 ±9.09; 50 men and 50 women), classified into two groups, as follows. Group I (G-I) consisted of 50 patients who underwent surgery for symptomatic LDH, while group II (G-II) consisted of 50 patients with nonspecific complaints of a headache, but with no previous history of back and/or leg pain, recruited among patients admitted to the outpatient clinic at the time of the study, and whose age and sex were matched to the study group. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose, and hemoglobin A_1c levels were measured. The TC/HDL-C ratio was calculated. Blood pressure, waist circumference, body mass index, and the history of smoking were included in the analysis.

RESULTS

The mean values of the TC, TG, LDL-C, HDL-C levels and TC/HDL-C ratio were 198.38, 132.76, 131.9, 40.38 mg/dl and 5.09, respectively. No statistically significant relationship between the blood lipid profile and LDH was identified in this population.

CONCLUSIONS

Blood lipid levels in this young adult Turkish population did not predict LDH, and may not be a leading cause of IVD ischemia and IVD degeneration.