Vitamin D receptor gene polymorphisms and risk of intervertebral disc degeneration: An updated meta-analysis based on 23 studies

Exploring extracellular vesicles as novel therapeutic agents for intervertebral disc degeneration: delivery, applications, and mechanisms

Intervertebral disc degeneration is a multifactorial degenerative disease that poses a significant threat to the health of the elderly population. Current treatments primarily focus on physical therapy, medication, and surgery to alleviate symptoms associated with disc compression but do not address the progression of degeneration. Therefore, this review aimed to explore the potential of extracellular vesicle therapy as a novel preventive strategy to delay degeneration and enhance tissue repair in intervertebral discs. We cover the pathogenic mechanisms underlying intervertebral disc degeneration, including inflammation, apoptosis, pyroptosis, ferroptosis, autophagy dysregulation, and the roles of non-coding RNAs. Subsequently, we discussed the therapeutic potential of extracellular vesicles and their molecular components, such as proteins, RNAs, and lipids, in modulating these pathways to counter intervertebral disc degeneration. We provides a comprehensive review of the significant role of extracellular vesicle cargo in mediating repair mechanisms. It discusses the functional enhancement advantages exhibited by extracellular vesicles under current bioengineering modifications and drug loading. The challenges and future prospects of utilizing extracellular vesicle therapy to treat this degenerative condition are also summarized.

Vitamin D deficiency promotes intervertebral disc degeneration via p38/NCoR2-mediated extracellular matrix degradation

PURPOSE

Vitamin D (VD) deficiency significantly contributes to intervertebral disc degeneration (IDD), a common cause of low back pain, yet the underlying mechanisms remain unclear. This study investigates how VD deficiency exacerbates IDD and identifies potential therapeutic targets.

METHODS

We used real-time quantitative PCR, immunoblots, immunoprecipitation, liquid chromatography with tandem mass spectrometry analysis, co-immunoprecipitation, and chromatin immunoprecipitation to study gene and protein expressions, protein complex assembly, and transcriptional complex binding. Degeneration of IVDs was assessed via hematoxylin and eosin staining.

RESULTS

Eight members of ADAMTSs (A disintegrin and metalloproteinase with thrombospondin motifs) are enriched in lumbar discs of both VD-deficient and VD receptor (VDR)-knockout (VDR-/-) mice. Sufficient VD suppresses ADAMTS genes through a complex formed by nuclear receptor corepressor 2 (NCoR2) and signal transducer and activator of transcription 6 (STAT6). VD deficiency activates p38 kinase, leading to NCoR2 phosphorylation and subsequent degradation by a Cullin 4-RING (CRL4) E3 ligase, impairing NCoR2's transrepression function and upregulating ADAMTS genes, accelerating extracellular matrix (ECM) degradation in discs. This mechanism is replicated in VDR-deficient cells. In vitro treatments with p38 inhibitor (BIRB-796) and CRL4 inhibitor (KH-4-43) reduce ADAMTS expression, and in vivo application of these inhibitors improves disc integrity in VD-deficient mice.

CONCLUSION

Our findings highlight NCoR2 degradation, mediated by p38 kinase and CRL4 E3 ligase, as crucial in VD deficiency-induced IDD. Targeting this pathway offers promising therapeutic potential to mitigate IDD progression in individuals with VD deficiency or VDR abnormalities.

A Case-Control Study of the Fokl Polymorphism of the Vitamin D Receptor Gene in Bulgarians With Lumbar Disc Herniation

BACKGROUND

The present study investigates whether vitamin D receptor (VDR) gene polymorphisms play a role in intervertebral disc degeneration (IDD), a common cause of low back pain (LBP) and reduced quality of life. Specifically, we examined the FokI VDR polymorphism and its potential association with lumbar disc herniation (LDH) in patients from Bulgaria. Previous studies have suggested a link between mutations in the VDR gene and IDD.

METHODS

We investigated whether a potential connection between VDR polymorphisms and LDH was present by comparing the FokI polymorphism of 60 selected patients (25 to 60) with LDH and 60 healthy volunteers within the same age range. We used polymerase chain reaction to assess the phenotype of the examined subjects and statistical tests to evaluate whether the obtained results were statistically significant.

RESULTS

The performed genetic and statistical analyses reviewed significant differences in genotypic frequencies between the patient group and healthy volunteers. The frequency of the F allele is notably higher in patients with LDH (80%) compared to volunteers (52%), while the f allele is more common among patients (86.6%) than volunteers (100%).

CONCLUSION

This study strongly suggests that expression of the F allele of the VDR gene may increase the susceptibility of developing LDH, while having the f allele could potentially have a protective effect. Our results shed light on the underlying complex mechanisms contributing to the development of LDH.

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.

Cytokine Imbalance as a Biomarker of Intervertebral Disk Degeneration

The intervertebral disk degeneration (IDD) and its associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. IDD progresses with age, leading to spondylosis, spondylarthrosis, intervertebral disk herniation, and spinal stenosis. The purpose of this review is an attempt to summarize the data characterizing the patterns of production of pro-inflammatory and anti-inflammatory cytokines in IDD and to appreciate the prognostic value of cytokine imbalance as its biomarker. This narrative review demonstrates that the problem of evaluating the contribution of pro-inflammatory and anti-inflammatory cytokines to the maintenance or alteration of cytokine balance may be a new key to unlocking the mystery of IDD development and new therapeutic strategies for the treatment of IDD in the setting of acute and chronic inflammation. The presented data support the hypothesis that cytokine imbalance is one of the most important biomarkers of IDD.

Targeting Autophagy for Developing New Therapeutic Strategy in Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is a prevalent cause of low back pain. IVDD is characterized by abnormal expression of extracellular matrix components such as collagen and aggrecan. In addition, it results in dysfunctional growth, senescence, and death of intervertebral cells. The biological pathways involved in the development and progression of IVDD are not fully understood. Therefore, a better understanding of the molecular mechanisms underlying IVDD could aid in the development of strategies for prevention and treatment. Autophagy is a cellular process that removes damaged proteins and dysfunctional organelles, and its dysfunction is linked to a variety of diseases, including IVDD and osteoarthritis. In this review, we describe recent research findings on the role of autophagy in IVDD pathogenesis and highlight autophagy-targeting molecules which can be exploited to treat IVDD. Many studies exhibit that autophagy protects against and postpones disc degeneration. Further research is needed to determine whether autophagy is required for cell integrity in intervertebral discs and to establish autophagy as a viable therapeutic target for IVDD.

Vitamin D receptor gene polymorphism influence on lumbar intervertebral disc degeneration

INTRODUCTION

Intervertebral disc degeneration is a multifaceted pathology that is the main morphological cause of lower back pain. This study aimed to determine the link between the vitamin D receptor gene single nucleotide polymorphisms (SNPs) and degenerative processes of the lumbar spine.

MATERIALS AND METHODS

The complete lumbar spinal columns were collected from 100 Caucasian cadavers via ventral dissection. The specimens for the histological analysis were harvested from the L5/S1 intervertebral discs and endplates. Then, the tissues were cut into slices, inserted into paraffin blocks, and stained. The histology was evaluated according to the Boos' protocol. Moreover, TaqI(rs731236), FokI(rs2228570), and ApaI(rs7975232) genotyping were performed. Lastly, the histological scores for different genotypes were analyzed.

RESULTS

The overall Boos' score in the study group was 12.49. It consisted of a mean intervertebral disc score of 7.46 and endplate score of 5.39. The determination of the SNPs was successful in 99 specimens and had a distribution of all alleles in accordance with the Hardy-Weinberg equilibrium. No significant differences in overall histological degeneration scores were found between samples from donors with different genotypes. However, in subgroup analysis of specific regions on the IVD, the significant difference was found in posterior inner anulus fibrosus for ApaI.

CONCLUSIONS

The results of this study suggest that one must be careful when interpreting the results of the clinical and/or radiological studies on vitamin D receptor gene polymorphisms and lumbar spine degeneration risk, because such a relationship, if present, is likely to be very subtle. This article is protected by copyright. All rights reserved.