Caspase 9 gene polymorphism and susceptibility to lumbar disc disease in the Han population in northern China

Immuno-Modulatory Effects of Intervertebral Disc Cells

Low back pain is a highly prevalent, chronic, and costly medical condition predominantly triggered by intervertebral disc degeneration (IDD). IDD is often caused by structural and biochemical changes in intervertebral discs (IVD) that prompt a pathologic shift from an anabolic to catabolic state, affecting extracellular matrix (ECM) production, enzyme generation, cytokine and chemokine production, neurotrophic and angiogenic factor production. The IVD is an immune-privileged organ. However, during degeneration immune cells and inflammatory factors can infiltrate through defects in the cartilage endplate and annulus fibrosus fissures, further accelerating the catabolic environment. Remarkably, though, catabolic ECM disruption also occurs in the absence of immune cell infiltration, largely due to native disc cell production of catabolic enzymes and cytokines. An unbalanced metabolism could be induced by many different factors, including a harsh microenvironment, biomechanical cues, genetics, and infection. The complex, multifactorial nature of IDD brings the challenge of identifying key factors which initiate the degenerative cascade, eventually leading to back pain. These factors are often investigated through methods including animal models, 3D cell culture, bioreactors, and computational models. However, the crosstalk between the IVD, immune system, and shifted metabolism is frequently misconstrued, often with the assumption that the presence of cytokines and chemokines is synonymous to inflammation or an immune response, which is not true for the intact disc. Therefore, this review will tackle immunomodulatory and IVD cell roles in IDD, clarifying the differences between cellular involvements and implications for therapeutic development and assessing models used to explore inflammatory or catabolic IVD environments.

Caspase-9: A Multimodal Therapeutic Target With Diverse Cellular Expression in Human Disease

Caspase-9, a cysteine-aspartic protease known for its role as an initiator of intrinsic apoptosis, regulates physiological cell death and pathological tissue degeneration. Its nonapoptotic functions, including regulation of cellular differentiation/maturation, innate immunity, mitochondrial homeostasis, and autophagy, reveal a multimodal landscape of caspase-9 functions in health and disease. Recent work has demonstrated that caspase-9 can drive neurovascular injury through nonapoptotic endothelial cell dysfunction. CASP9 polymorphisms have been linked with various cancers, neurological disorders, autoimmune pathologies and lumbar disc disease. Clinical reports suggest alterations in caspase-9 expression, activity or function may be associated with acute and chronic neurodegeneration, retinal neuropathy, slow-channel myasthenic syndrome, lumbar disc disease, cardiomyopathies, atherosclerosis and autoimmune disease. Healthy tissues maintain caspase-9 activity at low basal levels, rendering supraphysiological caspase-9 activation a tractable target for therapeutic interventions. Strategies for selective inhibition of caspase-9 include dominant negative caspase-9 mutants and pharmacological inhibitors derived from the XIAP protein, whose Bir3 domain is an endogenous highly selective caspase-9 inhibitor. However, the mechanistic implications of caspase-9 expression and activation remain indeterminate in many pathologies. By assembling clinical reports of caspase-9 genetics, signaling and cellular localization in human tissues, this review identifies gaps between experimental and clinical studies on caspase-9, and presents opportunities for further investigations to examine the consequences of caspase activity in human disease.

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.

TRAIL gene 1595C/T polymorphisms contribute to the susceptibility and severity of intervertebral disc degeneration: a data synthesis

Background

Studies have investigated the correlation between tumor necrosis factor related apoptosis-inducing ligand (TRAIL) gene polymorphisms and the susceptibility and severity of intervertebral disc degeneration (IDD), but the results were inconsistent. To evaluate the specific relationship, we performed a meta-analysis to clarify the controversies.

Methods

Four databases were searched, and the pooled results were presented as odds ratios (ORs) with 95% confidence intervals (CIs).

Results

Three case-control studies from Han Chinese were included (565 cases and 427 controls). All the included studies reported TRAIL 1595C/T gene polymorphisms. The recessive model (CC vs. CT + TT) was the optimal model, which demonstrated a significant relationship between 1595C/T polymorphisms and increased IDD risk (OR = 2.18, 1.45 to 3.27, P = 0.000). No significant heterogeneity was found in the recessive model (I² = 48.6%, P = 0.143). Patients with lower grade IDD had more genotypes or alleles including 1595TT genotype (grade II vs. grade III: OR = 2.12, 1.18 to 3.83, P = 0.012; grade III vs. grade IV: OR = 2.59, 1.29 to 5.22, P = 0.007) and 1595 T allele (grade II vs. grade III: OR = 1.91, 1.43 to 2.55, P = 0.000; grade II vs. grade IV: OR = 2.46, 0.94 to 1.76, P = 0.000).

Conclusions

There is a significant relationship between 1595C/T polymorphisms and the susceptibility and severity of IDD in Han Chinese. Patients with lower grade IDD had higher frequency of the 1595TT genotype and 1595 T allele.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12891-017-1916-3) contains supplementary material, which is available to authorized users.

Association of the Polymorphism of TRAIL with the Risk and Severity of Lumbar Disc Degeneration in Chinese Han Population

BACKGROUND

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis of various normal and tumor cells. Apoptosis plays an important role in the development of lumbar disc degeneration (LDD).

AIMS

The aim of this study was to determine whether the 1595C/T polymorphism of the TRAIL gene is associated with the increased risk and severity of LDD in the Chinese Han population.

METHODS

This study consisted of 312 patients with LDD and 196 healthy controls. The grade of disc degeneration was determined according to Schneiderman's classification for magnetic resonance imaging (MRI).

RESULTS

The genotype frequency of the 1595C/T polymorphism was in agreement with the Hardy-Weinberg equilibrium (p=0.278). Patients with LDD had significantly lower frequencies of CT and TT genotypes compared with normal controls (p<0.001). In addition, a lower frequency of the T allele was found in patients with LDD than normal controls (p<0.001). Unconditional logistic regression analysis revealed that CT and TT genotypes were both significantly associated with a reduced risk of LDD compared with the CC genotype (p<0.001; odds ratio [OR] 0.327; 95% confidence interval [95% CI] 0.217-0.493 and p<0.001; OR 0.393; 95% CI 0.234-0.661, respectively). Furthermore, the T allele was significantly associated with a decreased risk of LDD compared with the C allele (p<0.001; OR 0.483; 95% CI 0.369-0.633). In addition, the CT and TT genotypes, as well as the T allele, were associated with lower degenerative grades of LDD compared with the CC genotype and the C allele, respectively (p=0.008 and p=0.001, respectively).

CONCLUSION

The 1595C/T polymorphism of TRAIL may be adversely associated with the risk and severity of LDD in the Chinese Han population.

Analysis of association between IL-1β, CASP-9, and GDF5 variants and low-back pain in Chinese male soldier: clinical article

OBJECT

Recent studies have suggested that genetic risk factors play an important role in the occurrence of low-back pain (LBP) and lumbar disc disease. The authors' study aimed to assess the association between 3 single-nucleotide polymorphisms (SNPs) and susceptibility to LBP related to military training.

METHODS

In this case-control study, data from 892 Chinese male soldiers were retrospectively reviewed. The case group was made up of 305 soldiers with LBP related to military training and a control group of 587 soldiers without constant LBP for more than 2 weeks. Genomic DNA was extracted from peripheral blood leukocytes of all subjects and polymerase chain reaction products were genotyped.

RESULTS

No association was found between the SNP of interleukin-1β (IL-1β; +3954C/T) and LBP at both the genotypic (p = 0.104) and the allelic (p = 0.098) level. However, the G allele of caspase-9 (CASP-9) and the T allele of growth differentiation factor 5 (GDF5) were more common in patients with LBP than in patients without LBP (p < 0.001).

CONCLUSIONS

The findings in a Chinese military cohort indicated that CASP-9 (-1263A/G) and GDF5 (+104T/C) polymorphisms are associated with a susceptibility to LBP related to military training.

Association of the polymorphism of DR4 with the risk and severity of lumbar disc degeneration in the Chinese Han population

OBJECTIVE

Death receptor 4 (DR4), an apoptosis-associated gene, plays an important role in the pathophysiology of lumbar disc degeneration (LDD). The present study aimed to determine whether the C626G polymorphism (rs4871857) of the DR4 gene is associated with the risk and severity of LDD in the Chinese Han population.

METHODS

A total of 296 patients with LDD and 208 healthy controls were enrolled in this study. The grade of disc degeneration was determined according to Schneiderman's classification for MRI. The C626G polymorphism of DR4 was genotyped using polymerase chain reaction and the restriction fragment length polymorphism method.

RESULTS

The genotype frequency of the C626G polymorphism was in agreement with the Hardy-Weinberg equilibrium (p = 0.194). The frequencies of the 626CG and GG genotypes were higher among LDD patients compared with normal controls; however, the differences were not significant. Patients with LDD showed significantly higher frequencies of the G allele than normal controls (p = 0.023). Unconditional logistic regression analysis revealed that the G allele was significantly associated with an increased risk of LDD compared with the C allele (p = 0.025; OR 1.958; 95% CI 1.087-3.526). However, no association was found between the different genotypes and the risk of LDD. In addition, the 626CG and GG genotypes, as well as the G allele were associated with higher degenerative grades of LDD compared with the CC genotype and the C allele, respectively (p = 0.005 and p < 0.001, respectively).

CONCLUSION

The C626G polymorphism of DR4 may be associated with the risk and severity of LDD in the Chinese Han population.

Stemming the Degeneration: IVD Stem Cells and Stem Cell Regenerative Therapy for Degenerative Disc Disease

The intervertebral disc (IVD) is immensely important for the integrity of vertebral column function. The highly specialized IVD functions to confer flexibility and tensile strength to the spine and endures various types of biomechanical force. Degenerative disc disease (DDD) is a prevalent musculoskeletal disorder and is the major cause of low back pain and includes the more severe degenerative lumbar scoliosis, disc herniation and spinal stenosis. DDD is a multifactorial disorder whereby an imbalance of anabolic and catabolic factors, or alterations to cellular composition, or biophysical stimuli and genetic background can all play a role in its genesis. However, our comprehension of IVD formation and theetiology of disc degeneration (DD) are far from being complete, hampering efforts to formulate appropriate therapies to tackle DD. Knowledge of the stem cells and various techniques to manipulate and direct them to particular fates have been promising in adopting a stem-cell based regenerative approach to DD. Moreover, new evidence on the residence of stem/progenitor cells within particular IVD niches has emerged holding promise for future therapeutic applications. Existing issues pertaining to current therapeutic approaches are also covered in this review.

Genetic association studies in lumbar disc degeneration: a systematic review

Objective

Low back pain is associated with lumbar disc degeneration, which is mainly due to genetic predisposition. The objective of this study was to perform a systematic review to evaluate genetic association studies in lumbar disc degeneration as defined on magnetic resonance imaging (MRI) in humans.

Methods

A systematic literature search was conducted in MEDLINE, MEDLINE In-Process, SCOPUS, ISI Web of Science, The Genetic Association Database and The Human Genome Epidemiology Network for information published between 1990–2011 addressing genes and lumbar disc degeneration. Two investigators independently identified studies to determine inclusion, after which they performed data extraction and analysis. The level of cumulative genetic association evidence was analyzed according to The HuGENet Working Group guidelines.

Results

Fifty-two studies were included for review. Forty-eight studies reported at least one positive association between a genetic marker and lumbar disc degeneration. The phenotype definition of lumbar disc degeneration was highly variable between the studies and replications were inconsistent. Most of the associations presented with a weak level of evidence. The level of evidence was moderate for ASPN (D-repeat), COL11A1 (rs1676486), GDF5 (rs143383), SKT (rs16924573), THBS2 (rs9406328) and MMP9 (rs17576).

Conclusions

Based on this first extensive systematic review on the topic, the credibility of reported genetic associations is mostly weak. Clear definition of lumbar disc degeneration phenotypes and large population-based cohorts are needed. An international consortium is needed to standardize genetic association studies in relation to disc degeneration.

Association of FAS and FAS ligand polymorphisms with the susceptibility and severity of lumbar disc degeneration in Chinese Han population

CONTEXT

Apoptosis is involved in the mechanism of lumbar disc degeneration (LDD).

OBJECTIVE

We aim to determine whether the polymorphisms of FAS and FASL are associated with the presence and severity of LDD.

METHODS

A total of 348 patients with LDD and 215 healthy controls were genotyped.

RESULTS

Patients with LDD showed higher frequency of-1377GA and AA, as well as-844CT and TT genotypes than normal controls. These genotypes were found to be associated with the risk of higher grades of LDD.

CONCLUSION

The polymorphisms of FAS and FASL may be associated with the presence and severity of LDD.