Association of collagen I, IX and vitamin D receptor gene polymorphisms with radiological severity of intervertebral disc degeneration in Southern European Ancestor

Lipid metabolic disorders and their impact on cartilage endplate and nucleus pulposus function in intervertebral disk degeneration

Lipid metabolism encompasses the processes of digestion, absorption, synthesis, and degradation of fats within biological systems, playing a crucial role in sustaining normal physiological functions. Disorders of lipid metabolism, characterized by abnormal blood lipid levels and dysregulated fatty acid metabolism, have emerged as significant contributors to intervertebral disk degeneration (IDD). The pathogenesis of IDD is multifaceted, encompassing genetic predispositions, nutritional and metabolic factors, mechanical stressors, trauma, and inflammatory responses, which collectively facilitate the progression of IDD. Although the precise mechanisms underlying IDD remain incompletely elucidated, there is substantial consensus regarding the close association between lipid metabolism disorders and its development. Intervertebral disks are essential for maintaining spinal alignment. Their primary functions encompass shock absorption, preservation of physiological curvature, facilitation of movement, and provision of stability. The elasticity and thickness of these disks effectively absorb daily impacts, safeguard the spine, uphold its natural curvature and flexibility, while also creating space for nerve roots to prevent compression and ensure normal transmission of nerve signals. Research indicates that such metabolic disturbances may compromise the functionality of cartilaginous endplates (CEP) and nucleus pulposus (NP), thereby facilitating IDD's onset and progression. The CEP is integral to internal material exchange and shock absorption while mitigating NP herniation under mechanical load conditions. As the central component of intervertebral disks, NP is essential for maintaining disk height and providing shock-absorbing capabilities; thus, damage to these critical structures accelerates IDD progression. Furthermore, lipid metabolism disorders contribute to IDD through mechanisms including activation of endoplasmic reticulum stress pathways, enhancement of oxidative stress levels, induction of cellular pyroptosis alongside inhibition of autophagy processes-coupled with the promotion of inflammation-induced fibrosis and fibroblast proliferation leading to calcification within intervertebral disks. This review delineates the intricate interplay between lipid metabolism disorders and IDD; it is anticipated that advancing our understanding of this pathogenesis will pave the way for more effective preventive measures and therapeutic strategies against IDD in future research.

Identification and Characterisation of Potential Targets for N6-methyladenosine (m6A) Modification during Intervertebral Disc Degeneration

BACKGROUND

The mechanism for RNA methylation during disc degeneration is unclear. The aim of this study was to identify N6-methyladenosine (m6A) markers and therapeutic targets for the prevention and treatment of intervertebral disc degeneration (IDD).

METHODS

Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and quantitative reverse transcription PCR (RT-qPCR) were employed to analyze m6A modifications of IDD-related gene expression. Bioinformatics was used to identify enriched gene pathways in IDD. m6A-RIP-qPCR was used to validate potential targets and markers.

RESULTS AND CONCLUSION

Human IDD samples exhibited a distinct m6A modification pattern that allowed associated genes and pathways to be identified. These genes had functions such as "nuclear factor kappa-B (NF-κB) binding" and "extracellular matrix components", which are crucial for IDD pathogenesis. ANXA2 showed increased m6A modification in IDD, while SLC3A2 and PBX3 showed decreased m6A methylation. The results of this study offer novel insights for the prevention and treatment of IDD.

Association of TaqI (rs731236) Polymorphism of Vitamin D Receptor Gene with Lumbar Degenerative Disc Disease

BACKGROUND

Lumbar degenerative disc disease (LDDD) significantly contributes to low back pain, with a complicated etiology involving genetic and environmental facts. The aim of study was to investigate the association between the TaqI (rs731236) polymorphism of the vitamin D receptor (VDR) gene with LDDD.

METHODS

In total, 248 patients with symptomatic LDDD and 146 control subjects were examined. The evaluation of clinical features of patients with LDDD comprised radiodiagnostic magnetic resonance imaging, neurologic examinations, pain scores including the visual analog scale (VAS), and disability investigation with Oswestry Disability Index (ODI). Genotyping of the VDR gene polymorphism was conducted using polymerase chain reaction-based methods.

RESULTS

Individuals of the LDDD group who were VDR TaqI AA genotype carriers were significantly greater than the other group (P = 0.014), whereas those with GG genotype were significantly lower (P = 0.028) in the patient group. In addition, VAS and ODI scores were significantly lower in the GG genotype carrier group, whereas AA genotype carriers had the greatest scores (P = 0.004). Carrying the G allele decreased the risk of LDDD 1.7 times (P = 0.014) and carrying the A allele enhanced the risk 1.8 times (P = 0.028). Moreover, G-allele carriers had significantly lower VAS (P = 0.002) and ODI scores (P < 0.0001).

CONCLUSIONS

VDR TaqI (rs731236) GG genotype and G allele have protective potential, whereas the AA genotype and A allele are risk factors for LDDD. The findings reveal a statistically significant association of the TaqI (rs731236) polymorphism of VDR gene polymorphism with LDDD. This result highlights the potential role of genetic factors in developing LDDD and suggests avenues for future research in genetic screening and personalized treatment strategies.

Research on the role and mechanism of IL-17 in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is one of the primary causes of low back pain (LBP), which seriously affects patients' quality of life. In recent years, interleukin (IL)-17 has been shown to be highly expressed in the intervertebral disc (IVD) tissues and serum of patients with IDD, and IL-17A has been shown to promote IDD through multiple pathways. We first searched databases such as PubMed, Cochrane, Embase, and Web of Science using the search terms "IL-17 or interleukin 17″ and "intervertebral discs". The search period ranged from the inception of the databases to December 2023. A total of 24 articles were selected after full-text screening. The main conclusion of the clinical studies was that IL-17A levels are significantly increased in the IVD tissues and serum of IDD patients. The results from the in vitro studies indicated that IL-17A can activate signaling pathways such as the NF-κB and MAPK pathways; promote inflammatory responses, extracellular matrix degradation, and angiogenesis; and inhibit autophagy in nucleus pulposus cells. The main finding of the in vivo experiments was that puncture of animal IVDs resulted in elevated levels of IL-17A within the IVD, thereby inducing IDD. Clinical studies, in vitro experiments, and in vivo experiments confirmed that IL-17A is closely related to IDD. Therefore, drugs that target IL-17A may be novel treatments for IDD, providing a new theoretical basis for IDD therapy.

Progress in the study of molecular mechanisms of intervertebral disc degeneration

Degenerative intervertebral disc disease (IVDD) is one of the main spinal surgery, conditions, which markedly increases the incidence of low back pain and deteriorates the patient's quality of life, and it imposes significant social and economic burdens. The molecular pathology of IVDD is highly complex and multilateral however still not ompletely understood. New findings indicate that IVDD is closely associated with inflammation, oxidative stress, cell injury and extracellular matrix metabolismdysregulation. Symptomatic management is the main therapeutic approach adopted for IVDD, but it fails to address the basic pathological changes and the causes of the disease. However, research is still focusing on molecular aspects in terms of gene expression, growth factors and cell signaling pathways in an attempt to identify specific molecular targets for IVDD treatment. The paper summarizes the most recent achievements in molecularunderstanding of the pathogenesis of IVDD and gives evidence-based recommendations for clinical practice.

A new perspective on intervertebral disc calcification-from bench to bedside

Disc degeneration primarily contributes to chronic low back and neck pain. Consequently, there is an urgent need to understand the spectrum of disc degeneration phenotypes such as fibrosis, ectopic calcification, herniation, or mixed phenotypes. Amongst these phenotypes, disc calcification is the least studied. Ectopic calcification, by definition, is the pathological mineralization of soft tissues, widely studied in the context of conditions that afflict vasculature, skin, and cartilage. Clinically, disc calcification is associated with poor surgical outcomes and back pain refractory to conservative treatment. It is frequently seen as a consequence of disc aging and progressive degeneration but exhibits unique molecular and morphological characteristics: hypertrophic chondrocyte-like cell differentiation; TNAP, ENPP1, and ANK upregulation; cell death; altered Pi and PPi homeostasis; and local inflammation. Recent studies in mouse models have provided a better understanding of the mechanisms underlying this phenotype. It is essential to recognize that the presentation and nature of mineralization differ between AF, NP, and EP compartments. Moreover, the combination of anatomic location, genetics, and environmental stressors, such as aging or trauma, govern the predisposition to calcification. Lastly, the systemic regulation of calcium and Pi metabolism is less important than the local activity of PPi modulated by the ANK-ENPP1 axis, along with disc cell death and differentiation status. While there is limited understanding of this phenotype, understanding the molecular pathways governing local intervertebral disc calcification may lead to developing disease-modifying drugs and better clinical management of degeneration-related pathologies.

A novel missense COL9A3 variant in a pedigree with multiple lumbar disc herniation

Trp3 allele in COL9A3 gene has been widely studied in populations with intervertebral disc disease. We identified a novel pathogenic variant in COL9A3 gene in a pedigree with multiple lumbar disc herniation (LDH). The proband was a 14-year-old boy who developed LDH at the L4/5 and L5/S1 spinal segments. His father, paternal aunt and grandfather were diagnosed with LDH at an age of 35, 30 and 23, respectively. By applying whole exome sequencing, a heterozygous missense variant (c.1150C > T, p.Arg384Trp) in COL9A3 was identified. According to the ACMG guidelines, this variant is predicted to be pathogenic. In addition, prediction tools found COL9A3 protein of this variant a reduced stability, some changed charge properties, and an altered spatial conformation. Findings expanded the mutational spectrum of LDH and contributed to the understanding of COL9A3 in the pathogenesis of LDH.

Intervertebral disc degeneration-Current therapeutic options and challenges

Degeneration of the intervertebral disc (IVD) is a normal part of aging. Due to the spine's declining function and the development of pain, it may affect one's physical health, mental health, and socioeconomic status. Most of the intervertebral disc degeneration (IVDD) therapies today focus on the symptoms of low back pain rather than the underlying etiology or mechanical function of the disc. The deteriorated disc is typically not restored by conservative or surgical therapies that largely focus on correcting symptoms and structural abnormalities. To enhance the clinical outcome and the quality of life of a patient, several therapeutic modalities have been created. In this review, we discuss genetic and environmental causes of IVDD and describe promising modern endogenous and exogenous therapeutic approaches including their applicability and relevance to the degeneration process.

Are serum thyroid hormone, parathormone, calcium, and vitamin D levels associated with lumbar spine degeneration? A cross-sectional observational clinical study

PURPOSE

Low back pain (LBP) impairs the quality of life and rises healthcare costs. The association of spine degeneration and LBP with metabolic disorders have been reported, previously. However, metabolic processes related with spine degeneration remained unclear. We aimed to analyze whether serum thyroid hormones, parathormone, calcium, and vitamin D levels were associated with lumbar intervertebral disc degeneration (IVDD), Modic changes, and fatty infiltration in the paraspinal muscles.

METHODS

We cross-sectionally analyzed a retrospective database. Patients who visited internal medicine outpatient clinics with suspect of endocrine disorders and chronic LBP were searched. Patients with biochemistry results within 1 week before lumbar spine magnetic resonance imaging (MRI) were included. Age- and gender-matched cohorts were made-up and analyzed.

RESULTS

Patients with higher serum free thyroxine levels were more likely to have severe IVDD. They were also more likely to have fattier multifidus and erector spinae at upper lumbar levels, less fatty psoas and less Modic changes at lower lumbar levels. Higher PTH levels were observed in patients with severe IVDD at L4-L5 level. Patients with lower serum vitamin D and calcium levels had more Modic changes and fattier paraspinal muscles at upper lumbar levels.

CONCLUSION

Serum hormone, vitamin D, and calcium levels were associated with not only IVDD and Modic changes but also with fatty infiltration in the paraspinal muscles, mainly at upper lumbar levels in patients with symptomatic backache presenting to a tertiary care center. Complex inflammatory, metabolic, and mechanical factors present in the backstage of spine degeneration.

Genetic variants of interleukin 1B and 6 are associated with clinical outcome of surgically treated lumbar degenerative disc disease

BACKGROUND

Successfully surgically treating degenerative disc diseases can be challenging to the spine surgeons, the long-term outcome relies on both the physical and mental status of the patient before and after treatment. Numerous studies underlined the role of inflammatory cytokines - like interleukin 1B and 6 - in the development of chronic diseases such as failed back surgery syndrome (FBSS) and major depressive disorder (MDD) which alter the outcome after spinal surgery. Our aim was to evaluate the associations of IL6 and IL1B gene polymorphisms with the long-term outcome of degenerative lumbar spine surgeries.

METHODS

An international genetical database (GENODISC) was combined with our institute's clinical database to create a large pool with long term follow up data. Altogether 431 patient's data were analysed. Patient reported outcome measures and surgical outcome was investigated in association with IL1B and IL6 SNPs with the help of 'SNPassoc' R genome wide association package.

RESULTS

Interleukin 1B variants analysis confirmed association with improvement of pain after surgery on individual SNP level and on haplotype level, moreover relationship with patient reported outcome and preoperative level of depression was found on individual SNP level. IL6 variants were associated with preoperative depression, somatization and with subsequent surgery.

CONCLUSION

Understanding the complexity of spinal surgery patients' long-term well-being is crucial in effectively treating chronic debilitating somatic diseases and the associated mental illnesses. Further studies should investigate more comprehensively the linkage of chronic physical and mental illnesses focusing on their simultaneous treatment.

Influence of Pregnancy on the Occurrence of Lumbar Spine Pain in Polish Women: A Retrospective Study

(1) Background: Low Back Pain is a major health concern. Pregnancy-related lower back pain is a common complaint among women. The aim of this study was to determine the influence of pregnancy history on the occurrence and profile of pain in the lower spine. (2) Methods: The diagnosis of Lower Back Pain during pregnancy was based on the authors’ questionnaire, Visual Analogue Scale (VAS), Oswestry Disability Index and Roland Morris Disability Questionnaire. The research group consisted of 1112 women who were students or came for various reasons to the Gynecology and Obstetrics Clinical Hospital of Poznan University of Medical Sciences and completed the questionnaires. Patients were divided into two groups. The first group consisted of women who had never been pregnant (never-pregnant, n = 872 (78.4%), and the second group consisted of women who had been pregnant at least once in their lives (ever-pregnant, n = 240 (21.6%)). (3) Results: In the never-pregnant and the ever-pregnant women, respectively, the intensity of pain was 4.6 ± 1.6 and 5.0 ± 2.0 on the VAS scale, the degree of disability on the Oswestry Disability Index Questionnaire was 5.0 ± 3.9 and 5.5 ± 4.4, while the impact of pain on functioning on the Roland Morris Disability Questionnaire was 3.9 ± 3.1 and 3.9 ± 3.3. There were no significant differences (Mann-Whitney U test) between the studied groups in the parameters tested. (4) Conclusions: Pregnancy is a risk factor for back pain during pregnancy, but one year or more after pregnancy the occurrence of back pain is similar to that in women who have never been pregnant.

Fundamentals of Intervertebral Disc Degeneration

Lumbar disc degeneration is one of the leading causes of chronic low back pain. The degenerative cascade is often initiated by an imbalance between catabolic and anabolic processes in the intervertebral discs. As a consequence of extracellular matrix degradation, neoinnervation and neovascularization take place. Ultimately, this degenerative process results in disc bulging and loss of nucleus pulposus and water content and subsequent loss of disc height. Most patients respond to conservative management and surgical interventions well initially, yet a significant number of patients continue to suffer from chronic low back pain. Because of the high prevalence of long-term discogenic pain, regenerative biological therapies, including gene therapies, growth factors, cellular-based injections, and tissue-engineered constructs, have attracted significant attention in light of their potential to directly address the degenerative process. Understanding the pathophysiology of degenerative disc disease is important in both refining existing technologies and developing innovative techniques to reverse the degenerative processes in the discs. In this review, we aimed to cover the underlying pathophysiology of degenerative disc disease as well as its associated risk factors and give a comprehensive summary about the developmental, structural, radiological, and biomechanical properties of human intervertebral discs.

Association between polymorphisms of collagen genes and susceptibility to intervertebral disc degeneration: a meta-analysis

BACKGROUND

Collagens are important structural components of intervertebral disc. A number of studies have been performed for association between polymorphisms of collagen genes and risk of intervertebral disc degeneration (IVDD) but yielded inconsistent results. Here, we performed a meta-analysis to investigate the association of collagen IX alpha 2 (COL9A2) Trp2, collagen IX alpha 3 (COL9A3) Trp3, collagen I alpha 1 (COL1A1) Sp1 and collagen XI alpha 1 (COL11A1) C4603T polymorphisms with susceptibility to IVDD.

METHOD

Eligible studies were retrieved by searching MEDLINE, EMBASE, Web of Science prior to 31 March, 2021. Odds ratio (OR) and corresponding 95% confidence interval (CI) were calculated for association strength.

RESULTS

A total of 28 eligible studies (31 datasets comprising 5497 cases and 5335 controls) were included. COL9A2 Trp2 carriers had an increased risk of IVDD than non-carriers in overall population (OR = 1.43, 95% CI 0.99-2.06, P = 0.058), which did not reach statistical significance. However, Trp2 carriers had 2.62-fold (95% CI 1.15-6.01, P = 0.022) risk than non-carriers in Caucasians. COL9A3 Trp3 was not associated with IVDD risk (OR = 1.28, 95% CI 0.81-2.02, P = 0.299). T allele and TT genotype of COL1A1 Sp1 (+ 1245G > T) were correlated with increased risk of IVDD. Significant associations were found between COL11A1 C4603T and IVDD risk under allelic (OR = 1.33, 95% CI 1.20-1.48), dominant (OR = 1.45, 95% CI 1.26-1.67), recessive (OR = 1.55, 95% CI 1.21-1.98) and homozygote model (OR = 1.81, 95% CI 1.40-2.34).

CONCLUSIONS

COL1A1 Sp1 and COL11A1 C4603T polymorphism are associated with IVDD risk while the predictive roles of collagen IX gene Trp2/3 need verification in more large-scale studies.

Association of Single Nucleotide Polymorphism rs2228570 with Lumbar Disc Degeneration: A Case-Control Study and Meta-Analysis

OBJECTIVE

To examine the association between single nucleotide polymorphisms (SNPs) rs2228570, rs731236, rs7975232, and rs1544410 and lumbar disc degeneration (LDD) predisposition.

METHODS

A search strategy was carried out, and the data were extracted after being chosen by the inclusion and exclusion criteria. Pooled odds ratios and 95% confidence intervals were calculated to assess the association between the aforementioned SNPs and LDD under allelic, dominant, recessive, heterozygous, and homozygous genetic models. In addition, a case-control study involving 46 LDD cases and 45 controls was also performed in the analysis to verify the result.

RESULTS

A total of 17 studies were included in this meta-analysis. The pooled results did not show any association between vitamin D receptor (VDR) gene polymorphisms and LDD. But, interestingly, in subgroup analysis, the rs2228570 polymorphism was associated with LDD under the allelic (OR = 0.70, 95% CI = 0.56-0.87, p = 0.002), recessive (OR = 0.60, 95% CI = 0.43-0.84, p = 0.003), and homozygous (OR = 0.47, 95% CI= 0.28-0.79, p = 0.004) genetic models in the Asian population. SNPs rs731236 and rs7975232 still did not show any obvious association. We obtained a similar result from the case-control study: rs2228570 had an obvious relationship with LDD under allelic and homozygous genetic models. At the same time, we found that rs2228570 was also associated with the degree of low back pain (visual analogue scale, VAS score) in LDD population.

CONCLUSION

SNP rs2228570 was significantly associated with LDD predisposition and the degree of low back pain in the Asian population.

The role of single nucleotide polymorphisms of IL-1A -889C>T (rs1800587), TNF-A -238G>A (rs361525), and VDR TaqI (rs731236) on susceptibility to herniated nucleus pulposus: a systematic review and meta-analysis

Background: The pathogenesis of herniated nucleus pulposus (HNP) is complex and may involve the wide variety of gene polymorphism. However, the reports from the existing studies are inconclusive. The objective of this study was to determine the role of single nucleotide polymorphisms (SNPs) in interleukin 1 alpha ( IL-1A), tumor necrosis factor-alpha ( TNF-A), and vitamin D receptor ( VDR) genes on the susceptibility to herniated nucleus pulposus (HNP). Methods: Four databases (PubMed, Embase, Cochrane, and Web of Science) were searched as of April 1 st, 2021. Authors, publication year, targeted genes, genotype and allele frequency in each case and control groups were collected. Newcastle-Ottawa scale was used to evaluate the publication quality. The pooled estimates of association of IL-1A -889C>T (rs1800587), TNF-A -238G>A (rs361525), and VDR TaqI (rs731236) and susceptibility to HNP were assessed using Z test. Results: We screened 3,067 unique studies for eligibility and three, two and nine case-control studies on IL-1A -889C>T, TNF-A -238G>A, and VDR TaqI were included, respectively, in our meta-analysis. The studies consisting 369 HNP cases and 433 controls for IL-1A -889C>T, 252 cases and 259 controls for TNF-A -238G>A and 1130 cases and 2096 controls for VDR TaqI. Our pooled estimates indicated that there was no significant association of those SNPs with the susceptibility to HNP in any genotype, dominant model, recessive model, or allele comparations. Conclusion: Although individual studies suggested the important role of gene expression dysregulation associated with SNPs in IL-1A, TNF-A, and VDR, our data indicated that IL-1A -889C>T, TNF-A -238G>A, and VDR TaqI had weak association with HNP susceptibility in both genotypes and allele distributions. However, since heterogeneity was identified among studies included in this meta-analysis, further meta-analysis with a larger population and subgroup analysis on specific population are warranted to support this finding.

The role of single nucleotide polymorphisms of IL-1A -889C>T (rs1800587), TNF-A -238G>A (rs361525), and VDR TaqI (rs731236) on susceptibility to herniated nucleus pulposus

Background: The pathogenesis of herniated nucleus pulposus (HNP) is complex and may involve the wide variety of gene polymorphism. However, the reports from the existing studies are inconclusive. The objective of this study was to determine the role of single nucleotide polymorphisms (SNPs) in interleukin 1 alpha ( IL-1A), tumor necrosis factor-alpha ( TNF-A), and vitamin D receptor ( VDR) genes on the susceptibility to herniated nucleus pulposus (HNP). Methods: Four databases (PubMed, Embase, Cochrane, and Web of Science) were searched as of April 1 st, 2021. Authors, publication year, targeted genes, genotype and allele frequency in each case and control groups were collected. Newcastle-Ottawa scale was used to evaluate the publication quality. The pooled estimates of association of IL-1A -889C>T (rs1800587), TNF-A -238G>A (rs361525), and VDR TaqI (rs731236) and susceptibility to HNP were assessed using Z test. Results: We screened 3,067 unique studies for eligibility and three, two and nine case-control studies on IL-1A -889C>T, TNF-A -238G>A, and VDR TaqI were included, respectively, in our meta-analysis. The studies consisting 369 HNP cases and 433 controls for IL-1A -889C>T, 252 cases and 259 controls for TNF-A -238G>A and 1130 cases and 2096 controls for VDR TaqI. Our pooled estimates indicated that there was no significant association of those SNPs with the susceptibility to HNP in any genotype, dominant model, recessive model, or allele comparations. Conclusion: Although individual studies suggested the important role of gene expression dysregulation associated with SNPs in IL-1A, TNF-A, and VDR, our data indicated that IL-1A -889C>T, TNF-A -238G>A, and VDR TaqI had weak association with HNP susceptibility in both genotypes and allele distributions. However, since heterogeneity was identified among studies included in this meta-analysis, further meta-analysis with a larger population and subgroup analysis on specific population are warranted to support this finding.

The role of single nucleotide polymorphisms of IL-1A -889C>T (rs1800587), TNF-A -238G>A (rs361525), and VDR TaqI (rs731236) on susceptibility to herniated nucleus pulposus

Background: The objective of this study was to determine the role of single nucleotide polymorphisms (SNPs) in interleukin 1 alpha ( IL-1A), tumor necrosis factor-alpha ( TNF-A), and vitamin D receptor ( VDR) genes on the susceptibility to herniated nucleus pulposus (HNP). Methods: Four databases (PubMed, Embase, Cochrane, and Web of Science) were searched as of April 1 st, 2021. Authors, publication year, targeted genes, genotype and allele frequency in each case and control groups were collected. Newcastle-Ottawa scale was used to evaluate the publication quality. The pooled estimates of association of IL-1A -889C>T (rs1800587), TNF-A -238G>A (rs361525), and VDR TaqI (rs731236) and susceptibility to HNP were assessed using Z test and presented as odd ratio (OR) and 95% confidence intervals (95%CI). Results: We screened 3,067 unique studies for eligibility and three, two and nine studies on IL-1A -889C>T, TNF-A -238G>A, and VDR TaqI were included, respectively, in our meta-analysis. The studies consisting 369 HNP cases and 433 controls for IL-1A -889C>T, 252 cases and 259 controls for TNF-A -238G>A and 1130 cases and 2096 controls for VDR TaqI. Our pooled estimates indicated that there was no significant association of those SNPs with the susceptibility to HNP in any genotype, dominant model, recessive model, or allele comparations. Conclusion: Although individual studies suggested the important role of gene expression dysregulation associated with SNPs in IL-1A, TNF-A, and VDR, our data indicated that IL-1A -889C>T, TNF-A -238G>A, and VDR TaqI had weak association with HNP susceptibility in both genotypes and allele distributions. However, since heterogeneity was identified among studies included in this meta-analysis, further meta-analysis with a larger population and subgroup analysis on specific population are warranted to support this finding.

Pathomechanism and Biomechanics of Degenerative Disc Disease: Features of Healthy and Degenerated Discs

The human intervertebral disc (IVD) is a complex organ composed of fibrous and cartilaginous connective tissues, and it serves as a boundary between 2 adjacent vertebrae. It provides a limited range of motion in the torso as well as stability during axial compression, rotation, and bending. Adult IVDs have poor innate healing potential due to low vascularity and cellularity. Degenerative disc disease (DDD) generally arises from the disruption of the homeostasis maintained by the structures of the IVD, and genetic and environmental factors can accelerate the progression of the disease. Impaired cell metabolism due to pH alteration and poor nutrition may lead to autophagy and disruption of the homeostasis within the IVD and thus plays a key role in DDD etiology. To develop regenerative therapies for degenerated discs, future studies must aim to restore both anatomical and biomechanical properties of the IVDs. The objective of this review is to give a detailed overview about anatomical, radiological, and biomechanical features of the IVDs as well as discuss the structural and functional changes that occur during the degeneration process.

Associations between vitamin D receptor gene polymorphisms and spinal degenerative disease: evidence from a meta-analysis based on 35 case-control studies

OBJECTIVE

Dozens of reports on the associations of vitamin D receptor (VDR) gene polymorphisms and susceptibility to spinal degenerative disease (SDD) were conducted with inconsistent findings. This study aimed to elucidate the associations through a meta-analysis approach.

METHODS

Databases of PubMed, EMBASE, Web of Science, CNKI, and Wanfang were searched until July 10, 2020. Study quality was evaluated by using Newcastle-Ottawa Scale (NOS). Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated to evaluate the associations under allelic model (1 vs. 2), homozygous model (11 vs. 22), heterozygous model (12 vs. 22), dominant model (11 + 12 vs. 22), and recessive model (11 vs. 12 + 22).

RESULTS

A total of 5021 cases and 5746 controls from 35 studies were eligible to this meta-analysis. According to NOS, the included studies were in excellent quality. In the overall population, the pooled data indicated that ApaI was associated with a reduced SDD susceptibility (AA vs. Aa + aa, OR = 0.83, 95%CI 0.71 - 0.96, P = 0.010). But the association was not observed in FokI, TaqI, and BsmI polymorphisms. Subgroup analysis suggested that TaqI polymorphism was correlated to an elevated SDD risk in Asians (TT + Tt vs. tt, OR = 2.55, 95%CI 1.90 - 3.44, P < 0.001).

CONCLUSION

The present study indicates that ApaI polymorphism may contribute to a reduced risk to SDD in the overall population, and TaqI polymorphism confers an elevated susceptibility to SDD in Asians. While, BsmI and FokI polymorphisms appear to have no significant association with SDD.

Lack of association between COL1A1 and COL9A2 single nucleotide polymorphisms and intervertebral disc degeneration

BACKGROUND

Collagens are the main components of the extracellular matrix of intervertebral discs. The genetic mutations in collagen genes could potentially play a causal role in pathophysiology of intervertebral disc degeneration (IVDD). In this study, we investigate the association of COL1A1 and COL9A2 single nucleotide polymorphisms (SNPs) with IVDD.

MATERIAL AND METHODS

ninety-six Iranian IVDD patients and 94 controls matched for age and sex were included. 5 cc of peripheral blood samples were obtained for DNA extraction using the Phenol-Chloroform method. The primers for SNPs COL1A1 rs909102 and COL9A2 were designed based on the TaqMan protocol and genotyped by real-time PCR with TaqMan.

RESULTS

The 'T' allele, 'CC' and 'TT' genotypes of COL1A1 rs909102 were more common among patients, however not significantly. Despite the similar allele distribution of COL9A2 rs137853213 in patients and controls, the homozygote genotypes were more frequent among patients, though this was not significant either.

CONCLUSION

The allele and genotype distributions of COL1A1 rs909102 and COL9A2 rs137853213 SNPs were not significantly associated with IVDD in an Iranian population.

GENETIC ASPECTS OF IDIOPATHIC ESCOLIOSIS - A LITERATURE REVIEW

ABSTRACT The idiopathic scoliosis (IS) is the most common form of spinal deformity. The pathogenesis of IS is still poorly understood. Several studies show evidence that the genetic component is determinant to the development of IS. In this setting, a crescent focus has been placed on the identification of genes, associated genetic polymorphisms, and multiple susceptibility loci. This review highlights the genes and genetic polymorphisms currently studied, identified as influential in the genesis of IS, such as MMP-3, IL-6, type I collagen, and vitamin D and estrogen receptors. We concluded that IS remains a complex disease with a polygenic background and that genetic polymorphisms are intrinsically related to this condition. Level of evidence III; Narrative Review.

Genetic Influence in Disc Degeneration - Systematic Review of Literature

Disc degeneration is a condition that compromises the intervertebral disc functions, which can lead to several important pathological processes, such as disc herniation and canal stenosis. Although its etiology is still unknown, more and more studies have demonstrated the preponderant role of genetic factors to the detriment of environmental factors. Aiming to review the current knowledge about the genes associated with intervertebral disc degeneration, we have performed a narrative review based on the medical literature in the English language from the last 10 years regarding this subject. We have concluded that several genes have been associated with disc degeneration in humans, including the genes for collagen I α-1 ( COL1A1 ), collagen IX ( COL9A2 and COL9A3 ), collagen XI ( COL11A2 ), interleukin 6 ( IL-6 ), aggrecan ( AGC1 ), vitamin D receptor ( VDR ), and matrix metalloproteinase 3 ( MMP-3) , in addition to microRNAs. Therefore, the present review emphasizes the latest advancements in the association of genes with specific phenotypes of degenerated discs, single-nucleotide polymorphisms, heritage and genetic-environmental interactions in relation to disc degeneration to help future reviews regarding the genetic mechanisms underlying these processes.

Vitamin D Receptor gene polymorphisms and plasma levels are associated with lumbar disc degeneration

The purpose of this study was to investigate the association of Vitamin D Receptor (VDR) gene polymorphisms and VDR levels with lumbar disc degeneration (LDD). TaqMan SNP Genotyping Assay was utilized to probe VDR gene polymorphisms including the FokI (rs2228570), ApaI (rs7975232) and TaqI (rs731236) in 454 patients with LDD and 485 controls. Enzyme-Linked Immunosorbent Assay (ELISA) was used to detect plasma VDR levels. The patients with LDD were divided into three subgroups (subgroup 1: lumbar disc herniation; subgroup 2: lumbar spinal stenosis; subgroup 3: lumbar spondylolisthesis) to further probe the association of plasma VDR levels and VDR gene polymorphisms and LDD. Moreover, immunohistochemistry (IHC) was implemented to evaluate VDR expression in lumbar degenerated disc and normal disc. Allele and genotype frequency of TaqI (rs731236) were significantly different in patients with LDD and controls (all P < 0.05). For TaqI polymorphism, the frequencies of T allele were significantly higher in the LDD patients compared with controls (OR = 1.319; 95%CI 1.091 to 1.595; P = 0.004, adjusted (OR = 1.319; 95%CI 1.091 to 1.595; P = 0.004, adjusted OR = 1.383; 95%CI 1.135 to 1.684; P = 0.016). Furthermore, the allele distribution showed a higher frequency of the T allele in the patients with lumbar disc herniation in subgroup 1 (OR = 1.384; 95% CI 1.105 to 1.732; P = 0.004, adjusted OR = 1.319; 95%CI 1.091 to 1.595; P = 0.016). Plasma VDR levels and VDR expression were significantly lower in patients with LDD compared with controls (all P < 0.05). Moreover, the TT genotype of TaqI polymorphism was significantly associated with lower plasma VDR levels in patients with LDD (P = 0.002). TaqI (rs731236) polymorphism was associated with a predisposition to LDD. Plasma VDR and VDR expression levels may be the marker for the occurrence and development of LDD.

Genetic variants in COL11A2 of lumbar disk degeneration among Chinese Han population

BACKGROUND

Lumbar disk disease (LDD) is a common musculoskeletal disorder. Several predisposing genetic and environmental risk factors have been established for symptomatic LDD.

METHODS

We conducted a case-control association study to investigate the role of the COL11A2 gene in LDD. Genotyping of 384 Chinese Han LDD patients and 384 Chinese Han controls was made for six single-nucleotide polymorphisms (SNPs) from COL11A2 by Agena Massarray. We evaluated these SNPs association with LDD using the chi-square test and genetic model analysis.

RESULTS

The strongest associations with LDD were observed for polymorphisms in rs2071025. Carriers of "A" allele had an increased risk of LDD (OR = 1.47, 95% CI = 1.20-1.80, p = 0.0002) as compared with the "G" allele in allele model. We found that rs2071025 were associated with LDD in female and male from the stratification analyses (p < 0.05). Genetic models showed that rs986522(C) significantly increased the risk of LDD in female; however, in males, we did not find significant associations between the rs986522 and LDD risk.

CONCLUSION

This study showed a genetic association with COL11A2 polymorphism in individuals with LDD. These data may provide novel insights into the pathogenesis of LDD, although further studies with larger numbers of participants worldwide are needed for validation of our conclusions.

Association of VDR-FokI and VDBP-Thr420Lys polymorphisms with cervical spondylotic myelopathy: A case-control study in the population of China

BACKGROUND

Cervical spondylotic myelopathy (CSM), a common degenerative disorder, is characterized by chronic progressive compression of the cervical spinal cord. The present case-control study aimed to explore the potential role of VDR-FokI and VDBP-Thr420Lys polymorphisms in the susceptibility to CSM in the Chinese population.

METHODS

The study enrolled 318 CSM patients and 282 healthy individuals whose clinical data were retrospectively analyzed. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used to genotype VDR-FokI and VDBP-Thr420Lys polymorphisms. The severity of CSM was assessed using the Japanese Orthopaedic Association (JOA) score with magnetic resonance imaging (MRI) of cervical vertebra. A nonconditional binary logistic regression model was conducted for assessing the risk factors of CSM.

RESULTS

Patients in the CSM group had longer time duration to bend over desk working than the control group. The ff genotype and f allele frequency of VDR-FokI were elevated in CSM patients. Elevated Ff + ff genotype and f allele frequency of VDR-FokI might increase the risk of CSM. The VDR-FokI polymorphism was associated with nucleus pulposus capillary invasion, necrosis, hyaline degeneration and fibrosis, genesis and hyperplasia of cartilage-like cells, and fibrocyst in the fibrous ring. The VDR-FokI and VDBP-Thr420Lys genotypes conformed to Hardy-Weinberg equilibrium which showed that VDR-FokI and VDBP-Thr420Lys had group representation characteristics.

CONCLUSION

Binary logistic regression analysis confirmed that VDR-FokI polymorphism and the time to bend over desk working were risk factors of CSM. Our results indicate that VDR-FokI polymorphism may be closely associated with the risk of CSM.

Serum 25-hydroxyvitamin D, serum calcium and vitamin D receptor (VDR) polymorphisms in a selected population with lumbar disc herniation-A case control study

Background

Association of Vitamin D receptor (VDR) polymorphisms with lumbar disc herniation (LDH) have been identified in several ethnic groups globally. Despite abundant sunlight, vitamin D deficiency is reported in many tropical countries. As vitamin D is a key modulator for intestinal calcium absorption, low vitamin D could contribute to low serum calcium leading to abnormalities of skeletal homeostasis. Therefore, present study was aimed to study the association of serum 25-hydroxyvitamin D (25(OH)D), serum calcium and VDR polymorphisms in a selected Sri Lankan population.

Materials & methods

A case control study was conducted in 119 participants (cases = 51: controls = 68). Serum 25(OH)D levels were measured using ELISA. The VDR polymorphisms (Fok I and Taq I) were detected by polymerase chain reaction followed by restriction fragment length polymorphism.

Results

Findings indicated a significantly low (p = 0.000) 25(OH)D levels in cases (18.7±3.7 ng/mL) compared to controls(25.5±9.8 ng/mL) while 25(OH)D in both groups were below the reference range. Mean serum calcium levels in both groups were within normal reference range and was not significantly different among groups. Statistically significant association was not observed between VDR Fok I polymorphisms among cases and controls. Although Fok I polymorphism genotypes were in Hardy-Weinberg equilibrium (HWE), Taq I genotypes in controls violated HWE.

Conclusion

Present study confirms that insufficient serum 25(OH)D levels in cases have major contribution to LDH. VDR Fok I polymorphisms did not have any significant association with LDH in Sri Lankan ethnicity.

Association of COL9A3 trp3 polymorphism with intervertebral disk degeneration: a meta-analysis

BACKGROUND

Intervertebral disk degeneration (IDD) is a common musculoskeletal disease associated with genetic factors. COL9A3 gene encodes the α3 (IX) chain of type IX collagen that is part of the interior structure of the disc. Mutations in COL9A3 gene sequence, leading to an Arg103Trp substitution in its 3 chain (the Trp3 allele at rs61734651 site), respectively, have been found to be connected with IDD occurrence in several studies. However, those studies have showed conflict results. Thus, a meta-analysis has been performed to assess the associations between the COL9A3 trp3 polymorphism and IDD.

METHODS

Data were gathered from the following four electronic databases: PubMed, Web of Science (WOS), Embase and Cochrane library up to January 01, 2018. The pooled odds ratio (polled ORs) and 95% confidence interval (CI) were calculated to evaluate the strength of relationship between the COL9A3 trp3 polymorphism and IDD.

RESULTS

Eleven eligible studies with 1631 cases of IDD and 1366 controls were included in this meta-analysis. The results indicated that the COL9A3 trp3 polymorphism was not associated with IDD (trp3 positive versus trp3 negative: OR = 1.31, 95%CI = 0.78-2.21, P = 0.309). Furthermore, the Egger's test and the Begg funnel plot did not show any evidence of publication bias.

CONCLUSIONS

Our results suggest that the COL9A3 trp3 polymorphism might not be associated with IDD. Nor did we find any relationship in subgroup analyses stratified by gender and ethnicity. Future researches with larger samples are required to verify this outcome.

Association of CILP, COL9A2 and MMP3 Gene Polymorphisms with Lumbar Disc Degeneration in an Indian Population

Lumbar disc degeneration (LDD) is a multifactorial disorder caused by genetic and environmental factors. Polymorphisms in several structural and inflammatory genes like collagens, aggrecan, matrix metalloproteinases are associated with the risk of disc degeneration. In this study, we analyzed the role of a few important single nucleotide polymorphisms in cartilage intermediate layer protein (CILP), collagen 9A2 (COL9A2) and matrix metalloproteinase 3 (MMP3) genes in LDD from an Indian population. Two hundred patients with LDD and 200 healthy controls were recruited for the study. Genotyping was performed by allelic discrimination assay. The rs2073711 polymorphism (CILP gene - GG genotype) was associated with reduced risk of LDD in the Indian population (OR = 0.43, p = 0.016). The rs591058 polymorphism (MMP3 gene - TT genotype) is found to be associated with lower risk among women (OR = 0.34, p = 0.041). No significant association was found between COL9A2 polymorphism rs7533552 and the risk of LDD. We conclude that the CILP gene polymorphism (rs2073711) is associated with a lower risk of LDD, the MMP3 (rs591058) gene polymorphism is associated with LDD among women, and the TT genotype confers a lower risk of LDD.

Collagen IX gene polymorphisms and lumbar disc degeneration: a systematic review and meta-analysis

Background

An increasing number of studies have investigated associations between collagen IX alpha 2 chain (COL9A2) and collagen IX alpha 3 chain (COL9A3) gene polymorphisms and the risk of lumbar disc degeneration (LDD). However, these studies have yielded contradictory results. The purpose of this meta-analysis is to investigate the association between the collagen IX gene polymorphisms (rs12077871, rs12722877, rs7533552 in COL9A2; rs61734651 in COL9A3) and LDD.

Methods

All relevant articles were collected from PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI). The last electronic search was performed on September 1, 2017. The allele/genotype frequencies were extracted from each study. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of associations under the five comparison genetic models. Statistical analysis was performed by Review Manager (RevMan) 5.31 software.

Results

The meta-analysis of 10 case-control studies, including 2102 LDD cases and 2507 controls, indicated that COL9A2 gene (rs12077871, rs12722877, rs7533552) and COL9A3 gene (rs61734651) polymorphisms were not associated with LDD (rs12077871: T vs. C, OR = 1.85, 95% CI = 0.87–3.91, P = 0.11; rs12722877: G vs. C, OR = 0.83, 95% CI = 0.69–1.01, P = 0.06; rs7533552: G vs. A, OR = 1.11, 95% CI = 0.98–1.25, P = 0.09; rs61734651: T vs. C, OR = 1.57, 95% CI = 0.51–4.84, P = 0.43). The Egger text and the Begg funnel plot did not show any evidence of publication bias.

Conclusion

rs12077871, rs12722877, and rs7533552 variants in COL9A2 and rs61734651 variant in COL9A3 were not significantly associated with a predisposition to LDD. Large-scale and well-designed studies are needed to confirm this conclusion.

Genetic background of degenerative disc disease in the lumbar spine

This is a review paper on the topic of genetic background of degenerative disc diseases in the lumbar spine. Lumbar disc diseases (LDDs), such as lumbar disc degeneration and lumbar disc herniation, are the main cause of low back pain. There are a lot of studies that tried to identify the causes of LDDs. The causes have been categorized into environmental factors and genetic factors. Recent studies revealed that LDDs are mainly caused by genetic factors. Numerous studies have been carried out using the genetic approach for LDDs. The history of these studies is divided into three periods: (1) era of epidemiological research using familial background and twins, (2) era of genomic research using DNA polymorphisms to identify susceptible genes for LDDs, and (3) era of functional research to determine how the genes cause LDDs. This review article was undertaken to present the history of genetic approach to LDDs and to discuss the current issues and future perspectives.

Influence of lifestyle characteristics and VDR polymorphisms as risk factors for intervertebral disc degeneration: a case-control study

BACKGROUND

Intervertebral disc degeneration (DD) is an important cause of low back pain and its precise aetiology is not fully understood, being attributed to cumulative environmental, biomechanical and genetic effects. The vitamin D plays a key role in regulation of calcium homeostasis and bone mineralization, exerting its biological activities by binding to a high-affinity receptor (VDR). Polymorphisms in VDR gene were previously associated with DD process, however with conflicting results. Here, we aimed to investigate the influence of lifestyle characteristics and VDR TaqI, BsmI, ApaI and FokI polymorphisms as risk factors for DD process.

METHODS

Retrospective case-control study involving 231 participants: 119 with confirmed DD and 112 healthy controls. Genotyping of VDR polymorphisms was performed by PCR-RFLP and real-time PCR using TaqMan methodology. All patients answered a questionnaire regarding lifestyle characteristics, such as educational level, pain localization, smoking habits, engagement of physical activity, postural and load weight at work and familial history of disc degeneration. The variables were compared between groups and adjusted by age and gender.

RESULTS

The case group was composed by 52% female and 48% male and the mean age was 40.0 years old, while in the control group 79% was female and 21% male and the mean age was 32.0 years old. Although gender distribution and mean age were different between groups, in the control group all participants were less than 45 years old and there was a prevalence of women in both groups. The factors that could be possibly associated to DD in the Brazilian population studied included smoking habits (26% in cases and 9% in controls, p = 0.003), lack of engagement in physical activity (observed in 77% of cases and 62% of controls, p = 0.018), and loading weight during work routine (58% in cases and 24% in controls, p ≤ 0.001). However, after adjusting by age and gender, only smoking habits remained associated to disc degeneration (p = 0.027). Considering the educational level, 35.2% of cases and 15.6% of controls had only the Elementary School, and 5.5% of DD group and 28.6% of control group had completed College (p = 0.025). In addition, educational level was directly associated to load weight at work (p = 0.012). Regarding VDR polymorphisms, no significant difference in genotype and allele frequencies between groups was observed. The haplotype analysis revealed that the combined wild-type alleles of TaqI, ApaI and FokI polymorphisms-TGT-was observed in a higher frequency in control group (p = 0.039).

CONCLUSION

The findings suggested that smoking habits was a risk factor for disc degeneration in the population studied. Single analysis revealed no significant effects of VDR polymorphisms in disc degeneration process, while the combination of wild-type alleles of TaqI, ApaI and FokI polymorphisms, TGT haplotype, decreased the risk of the disease.

Association analysis between thrombospondin-2 gene polymorphisms and intervertebral disc degeneration in a Chinese Han population

The aim of this study is to determine the contribution of 2 single nucleotide polymorphisms (SNPs) in thrombospondin 2 (THBS2) gene to the development of intervertebral disc degeneration (IDD) in a Chinese Han population.We studied 138 patients with radiographically proven IDD and 136 healthy volunteers with no history of back problems. Magnetic resonance images (MRIs) were obtained for all the patients and controls. Image evaluation for IDD was performed to evaluate the severity of IDD. All patients and controls were genotyped for rs6422747 and rs6422748. Associations between genotypes and development of IDD were analyzed.We found that 2 SNPs in the intron region of THBS2 gene (rs6422747 and rs6422748) were associated with susceptibility of IDD. However, they were not related with severity of IDD, including the total number of degenerative disc and level of IDD. G allele in both SNPs was associated with a higher risk of IDD.The 2 SNPs (rs6422747 and rs6422748) in the THBS2 gene were associated with susceptibility of IDD but not severity of IDD in a Chinese Han population. Our results indicated that THBS2 gene polymorphisms might be the risk factors for IDD. More studies with larger sample size need to be perfected to make sure the functions of THBS2 gene polymorphisms in IDD development.

Pregnancy-related low back pain in women in Turkey: Prevalence and risk factors

OBJECTIVES

To investigate the prevalence of pregnancy-related low back pain (PRLBP) in women in Turkey, identify the factors associated with PRLBP and predict the risk of PRLBP.

MATERIALS AND METHODS

This cross-sectional study included a total of 1500 pregnant women admitted to a prenatal care clinic in a secondary care hospital in Turkey between August 2011 and September 2014. All participants were asked to complete a survey questionnaire. The pregnant women who reported recurrent or continuous pain in the lumbar spine or pelvis for more than 1 week were offered a clinical examination for PRLBP by the spine physiatrist. The main outcome measure was the presence of PRLBP. We collected data on sociodemographic factors, previous obstetric history, daily habits, history of LBP, and functional disability scores as assessed by the Oswestry Disability Index (ODI).

RESULTS

The mean age of the 1500 women was 26.5±5.5 years. The prevalence of PRLBP was 53.9%, mostly in the third trimester. Women with PRLBP in the third trimester were more disabled than those in the first and second trimesters (mean ODI 40.0±16.7 vs. 34.9±19.2 and 37.4±15.3, respectively). Risk factors of PRLBP were history of LBP, PRLBP, and menstruation-related LBP as well as no housework assistance (OR=5.394, 95% CI: 3.128-9.300, P<0.001; 3.692, 2.745-4.964, P<0.001; 2.141, 1.563-2.932, P<0.001; 1.300, 1.029-1.64, P=0.028, respectively).

CONCLUSION

This cross-sectional study is the largest study of PRLBP in the literature and showed that about 1 in 2 women have PRLBP in any stage of pregnancy. History of LBP related and unrelated to previous pregnancy and menstruation are strong risk factors for PRLBP. Receiving no housework assistance is another risk factor.

Genetic analysis of the Vitamin D receptor start codon polymorphism (FokI) in cervical vertebra and lumbar spine pathologies: a meta-analysis

BACKGROUND

Vitamin D receptor (VDR) FokI polymorphism has been reported to influence the risk of spinal diseases. However, several studies suggest inconsistent results. Therefore, we performed this analysis to reveal the accurate relationship between VDR FokI polymorphism and spinal diseases.

MATERIALS AND METHODS

8 articles accord with the strict inclusion and exclusion criteria. 1116 cases and 1263 controls are entered into this analysis. The pooled odds ratios (ORs) and 95% confidence intervals (CI) are calculated to evaluate the association between VDR gene polymorphism and spinal diseases.

RESULT

The results suggest that allele F is a risk factor for spinal diseases and the difference is significant (F vs. f: OR = 1.151, 95% CI, 1.020-1.300). For the genotype analysis of VDR FokI, no statistical differences exist in the models of heterozygote comparison (Ff vs. ff), homozygote comparison (FF vs. ff) and dominant model (FF + Ff vs. ff) (p > 0.05). However, in recessive model (FF vs. Ff + ff), there is a significant association between VDR polymorphism and spinal diseases (OR = 1.209, 95% CI, 1.017-1.436). In subgroup analysis, the results show that allele F is a risk factor for spinal diseases in each estimation. In hospital-based subgroup, the significant differences exist in FF vs. ff and FF vs. Ff + FF models. In degenerative spine diseases group, the results are consistent with that of overall studies.

CONCLUSIONS

According to results of this meta-analysis, allele F is associated with the increased risk of spinal diseases. FF genotype may contribute to the susceptibility of spinal diseases. Therefore, VDR FokI polymorphism is related with spinal diseases.

Association between COL11A1 (rs1337185) and ADAMTS5 (rs162509) gene polymorphisms and lumbar spine pathologies in Chinese Han population: an observational study

OBJECTIVES

A previous study identified a significant association between several single nucleotide polymorphisms (SNPs) and lumbar disc degeneration (LDD) in Indians. To validate the association between these SNPs and specific lumbar spine pathologies, we performed a case-control study in Chinese Han population.

DESIGN

An observational study.

SETTING

University Hospital in Nanning, China.

PARTICIPANTS

This study included 428 patients with LDD and 400 normal controls.

OUTCOME MEASURES

Patients with LDD were classified into four subgroups, including disc herniation only (subgroup 1), discopathies or/and osteochondrosis associated with disc herniation (subgroup 2), spinal stenosis or/and spondylolisthesis (subgroup 3) and degenerative scoliosis (subgroup 4). This study was conducted by examining two aspects: environmental factors and SNP genotyping. The environmental factors were evaluated with a questionnaire survey including questions about body mass index, smoking habits, the physical demands of their job and exposure to vibrations. Rs1337185, rs5275, rs5277, rs7575934, rs3213718 and rs162509 were genotyped using a PCR-based invader assay.

RESULTS

The physical workload was significantly higher in patients with lumbar spine pathologies than in the normal controls (p=0.035). The genotype and allele frequencies of rs1337185 and rs162509 were significantly different between the patients with LDD and the normal controls. In rs1337185, a significant association was found between the C allele (risk allele) and the presence of disc herniation (OR=1.80; 95% CI 1.21 to 2.68; p=0.003, adjusted p=0.012) and the presence of spinal stenosis and spondylolisthesis (OR=1.92; 95% CI 1.29 to 2.89; p=0.001, adjusted p=0.004). In rs162509, the G allele represented 1.58-fold increased risk to suffer from disc herniation (OR=1.58; 95% CI 1.20 to 2.09; p=0.001, adjusted p=0.004).

CONCLUSION

The SNPs rs1337185 in COL11A1 and rs162509 in ADAMTS5 are associated with susceptibility to LDD. The C allele of rs1337185 is risky for patients who are affected by lumbar pathologies such as disc herniation, stenosis and spondylolisthesis. The G allele of rs16250 represents a risk factor for the development of disc herniation.

Genetic Alterations in Intervertebral Disc Disease

BACKGROUND

Intervertebral disc degeneration (IVDD) is considered a multifactorial disease that is influenced by both environmental and genetic factors. The last two decades of research strongly demonstrate that genetic factors contribute about 75% of the IVDD etiology. Recent total genome sequencing studies have shed light on the various single-nucleotide polymorphisms (SNPs) that are associated with IVDD.

AIM

This review presents comprehensive and updated information about the diversity of genetic factors in the inflammatory, degradative, homeostatic, and structural systems involved in the IVDD. An organized collection of information is provided regarding genetic polymorphisms that have been identified to influence the risk of developing IVDD. Understanding the proteins and signaling systems involved in IVDD can lead to improved understanding and targeting of therapeutics.

MATERIALS AND METHODS

An electronic literature search was performed using the National Library of Medicine for publications using the keywords genetics of IVDD, lumbar disc degeneration, degenerative disc disease, polymorphisms, SNPs, and disc disease. The articles were then screened based on inclusion criteria that included topics that covered the correlation of SNPs with developing IVDD. Sixty-five articles were identified as containing relevant information. Articles were excluded if they investigated lower back pain or just disc herniation without an analysis of disc degeneration. This study focuses on the chronic degeneration of IVDs.

RESULTS

Various genes were identified to contain SNPs that influenced the risk of developing IVDD. Among these are genes contributing to structural proteins, such as COL1A1, COL9A3, COL9A3, COL11A1, and COL11A2, ACAN, and CHST3. Furthermore, various SNPs found in the vitamin-D receptor gene are also associated with IVDD. SNPs related to inflammatory cytokine imbalance are associated with IVDD, although some effects are limited by sex and certain populations. SNPs in genes that code for extracellular matrix-degrading enzymes, such as MMP-1, MMP-2, MMP-3, MMP-9, MMP-14, ADAMTS-4, and ADAMTS-5 are also associated with IVDD. Apoptosis-mediating genes, such as caspase 9 gene (CASP9), TRAIL, and death receptor 4 (DR4), as well as those for growth factors, such as growth differentiation factor 5 and VEGF, are identified to have polymorphisms that influence the risk of developing IVDD.

CONCLUSION

Within the last 10 years, countless new SNPs have been identified in genes previously unknown to be associated with IVDD. Furthermore, the last decade has also revealed new SNPs identified in genes already known to be involved with increased risk of developing IVDD. Improved understanding of the numerous genetic variants behind various pathophysiological elements of IVDD could help advance personalized care and pharmacotherapeutic strategies for patients suffering from IVDD in the future.

How Reliable Are the Reported Genetic Associations in Disc Degeneration?: The Influence of Phenotypes, Age, Population Size, and Inclusion Sequence in 809 Patients

STUDY DESIGN

Prospective genetic association study.

OBJECTIVE

The aim of this study was to document the variations in the genetic associations, when different magnetic resonance imaging (MRI) phenotypes, age stratification, cohort size, and sequence of cohort inclusion are varied in the same study population.

SUMMARY OF BACKGROUND DATA

Genetic associations with disc degeneration have shown high inconsistency, generally attributed to hereditary factors and ethnic variations. However, the effect of different phenotypes, size of the study population, age of the cohort, etc have not been documented clearly.

METHODS

Seventy-one single-nucleotide polymorphisms (SNPs) of 41 candidate genes were correlated to six MRI markers of disc degeneration (annular tears, Pfirmann grading, Schmorl nodes, Modic changes, Total Endplate Damage score, and disc bulge) in 809 patients with back pain and/or sciatica. In the same study group, the correlations were then retested for different age groups, different sample, size and sequence of subject inclusion (first 404 and the second 405) and the differences documented.

RESULTS

The mean age of population (M: 455, F: 354) was 36.7 ± 10.8 years. Different genetic associations were found with different phenotypes: disc bulge with three SNPs of CILP; annular tears with rs2249350 of ADAMTS5 and rs11247361 IGF1R; modic changes with VDR and MMP20; Pfirmann grading with three SNPs of MMP20 and Schmorl node with SNPs of CALM1 and FN1 and none with Total End Plate Score.Subgroup analysis based on three age groups and dividing the total population into two groups also completely changed the associations for all the six radiographic parameters.

CONCLUSION

In the same study population, SNP associations completely change with different phenotypes. Variations in age, inclusion sequence, and sample size resulted in change of genetic associations. Our study questions the validity of previous studies and necessitates the need for standardizing the description of disc degeneration, phenotype selection, study sample size, age, and other variables in future studies.

LEVEL OF EVIDENCE

4.

Changes of proteoglycan and collagen II of the adjacent intervertebral disc in the cervical instability models

OBJECTIVE

Post-operation of cervical decompression fusion and internal fixation (CDF) accelerated adjacent segment disc degeneration (ASD). It is not clear that whether instability of one single segmental accelerates the degeneration of adjacent segment disc. This study aims to explore the effect of cervical instability on the change of morphology and biochemistry in adjective segment (above) in the L5/6 cervical instability rabbit models.

METHODS

Thirty-two mature New Zealand white rabbits (3000±250g) were randomly divided into two groups, control group (n=8) and model group (n=24). The animal models were established by destruction of partly annulus fibrosus and suction of nucleus pulposus. ASD was detected by X-ray after 4, 8 or 12 weeks surgery (8 model rabbits of each time). Animals were then euthanatized for cervical intervertebral disc tissue samples separation. Histomorphology, proteoglycan and collagen II of samples were detected.

RESULTS

Histomorphology data showed that notochord cells were decreased in C4/5 cervical nucleus pulposus and were replaced by fibroblast-like cells; a small amount cartilage cells were emerged; intervertebral disc anulus fibrosus becomes rough, disorganized, hyaline degeneration and pigmentation, in which contained fibrocartilage cells and cracks between the inner and outer layers. Proteoglycan content of nucleus pulposus was significantly decreased. Meanwhile, type II collagen of nucleus pulposus and annulus was also apparently reduced.

CONCLUSION

Cervical instability can alter morphology and reduce the content of proteoglycan and collagen II in adjacent intervertebral disc, thereby contributes adjacent intervertebral disc degeneration.

Vitamin D receptor gene polymorphisms and lumbar disc degeneration: a systematic review and meta-analysis

PURPOSE

To examine the association between Vitamin D receptor (VDR) gene polymorphisms and lumbar disc degeneration (LDD) predisposition.

METHODS

A comprehensive literature search was conducted to identify all the relevant studies. The allele/genotype frequencies were extracted from each study. We calculated the pooled odds ratios (ORs) and 95 % confidence intervals (CI) to assess the strength of the association between the VDR gene polymorphisms and LDD risk. Statistical analysis was performed using RevMan 5.31 software.

RESULTS

A total of 23 case-control studies (1835 cases and 1923 controls) were included in this systematic review. For the TaqI (rs731236), FokI (rs2228570) and ApaI (rs7975232) polymorphisms of VDR gene, nine studies, seven studies, and five studies, were eventually included in the meta-analysis, respectively. There was no evidence that the VDR gene polymorphisms (TaqI, FokI, ApaI) had significant associations with LDD risk.(for TaqI allelic comparison, OR = 1.07, 95 % CI 0.81-1.40, p = 0.64; for FokI allelic comparison, OR = 1.23, 95 % CI 0.83-1.82, p = 0.31; for ApaI allelic comparison, OR = 0.79, 95 % CI 0.55-1.14, p = 0.20). For stratified analyses by ethnicity and study design, no significant associations were found in Caucasian population and Asian population, as well as the population-based studies and hospital-based studies under all genetic models.

CONCLUSIONS

TaqI, FokI, and ApaI polymorphisms of VDR gene were not significantly associated with the predisposition of LDD. Large-scale and well-designed international studies are needed to further analyze this field.

Lumbar intervertebral disc degeneration and related factors in Korean firefighters

OBJECTIVES

The job of firefighting can cause lumbar burden and low back pain. This study aimed to identify the association between age and lumbar intervertebral disc degeneration and whether the association differs between field and administrative (non-field) firefighters.

METHODS

Subjects were selected using a stratified random sampling method. Firefighters were stratified by geographic area, gender, age and type of job. First, 25 fire stations were randomly sampled considering regional distribution. Then firefighters were stratified by gender, age and their job and randomly selected among the strata. A questionnaire survey and MRI scans were performed, and then four radiologists used Pfirrmann classification methods to determine the grade of lumbar intervertebral disc degeneration.

RESULTS

Pfirrmann grade increased with lumbar intervertebral disc level. Analysis of covariance showed that age was significantly associated with lumbar intervertebral disc degeneration (p<0.05). The value of β (parameter estimate) was positive at all lumbar intervertebral disc levels and was higher in the field group than in the administrative group at each level. In logistic regression analysis, type of job was statistically significant only with regard to the L4-5 intervertebral disc (OR 3.498, 95% CI 1.241 to 9.860).

CONCLUSIONS

Lumbar intervertebral disc degeneration is associated with age, and field work such as firefighting, emergency and rescue may accelerate degeneration in the L4-5 intervertebral disc. The effects of field work on lumbar intervertebral disc degeneration were not clear in discs other than at the level L4-5.

BsmI, ApaI and TaqI Polymorphisms in the Vitamin D Receptor Gene (VDR) and Association with Lumbar Spine Pathologies: An Italian Case-Control Study

Three adjacent single nucleotide polymorphisms of the vitamin D receptor gene (VDR) BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) are commonly studied in several pathologies. We aimed to evaluate the distribution of VDR BsmI, ApaI, and TaqI allele, genotype, and haplotype frequencies in an Italian cohort of 266 patients with lumbar spine disorders assessed by Magnetic Resonance Imaging and 252 asymptomatic controls. The exposure to putative risk factors was evaluated by a questionnaire. Polymorphisms were detected by PCR-RFLP and TaqMan^® SNP Genotyping Assay. The results were statistically adjusted for the identified conventional risk factors. The three SNPs were in linkage disequilibrium. For all cases BbAaTT was a 3-fold risk factor OR = 3.38), whereas bbAATT (OR = 0.22), and bbaaTT (OR = 0.47) genotypes were found to be protective. Specifically, for patients affected by disc herniation only (n = 88) and all lumbar pathologies excluding stenosis and/or spondylolistesis (n = 215) B allele, Bb, Aa, and BbAaTT genotypes were risky, whereas b allele, bb, aa, and bbaaTT genotypes were protective. In patients affected by osteochondrosis with or without disc hernation (n = 50), T allele, Aa, and bbAaTT genotypes were risky, whereas t allele, AA, tt genotypes were protective. In patients affected by stenosis and/or spondylolistesis (n = 51) no significant associations were found. This is the first study showing an association of the three genetic VDR variants BsmI, ApaI, and TaqI and lumbar spine pathologies. Our study contributes to delineate genetic risk factors for specific subgroups of patients with lumbar spine pathologies highlighting the importance of haplotype analysis, and of detailed clinical evaluation of the patients for identification of genetic biomarkers.

Intervertebral disc development and disease-related genetic polymorphisms

The intervertebral disc (IVD) comprises a gelatinous inner core (nucleus pulposus; NP) and concentric rings (annulus fibrosus; AF). The NP, an important structure for shock absorption in the vertebrate spinal motion segment, can be traced back to the notochord in ontogenetic lineage. In vertebrates, the notochord undergoes mucinoid changes, and had been considered vestigial until recently. However, observed correlations between IVD degeneration and back pain in humans have renewed interest in the IVD in biomedical fields. Beyond its mechanical contribution to development, the notochord is also an essential signaling center, which coordinates formation of the neural tube and somites. The pertinent signaling molecules, particularly TGF-β and bone morphogenetic proteins (BMPs), continue to play roles in the adult tissues and have been utilized for tissue regeneration. Genetic factors are major determinants of who will develop IVD degeneration and related back pain, and seem to correlate better with disc degeneration and back pain than do external forces on the spine. In summary, the spinal column is a landmark development in evolution. Genes directing the development of the IVD may also contribute to its maintenance, degeneration, and regeneration. Likewise, structural genes as well as genes responsible for maintenance of the structure are related to IVD degeneration. Finally, genes responsible for inflammation may play a dual role in exacerbating degeneration or facilitating repair responses depending on the context.

Autophagy: A double-edged sword in intervertebral disk degeneration

Autophagy is a homeostatic mechanism through which intracellular damaged organelles and proteins are degraded and recycled in response to increased metabolic demands or stresses. Although primarily cytoprotective, dysfunction of autophagy is often associated with many degenerative diseases, including intervertebral disc (IVD) degeneration (IDD). As a main contributing factor to low back pain, IDD is the pathological basis for various debilitating spinal diseases. Either higher or lower levels of autophagy are observed in degenerative IVD cells. Despite the precise role of autophagy in disc degeneration that is still controversial, with difference from protection to aggravation, targeting autophagy has shown promise for mitigating disc degeneration. In the current review, we summarize the changes of autophagy in degenerative IVD cells and mainly discuss the relationship between autophagy and IDD. With continued efforts, modulation of the autophagic process could be a potential and attractive therapeutic strategy for degenerative disc disease.