Genetic polymorphisms of TNF-α, IL-6, and IL-10 in female elderly patients with chronic temporomandibular disorder pain

The association between genetic factors and temporomandibular disorders: A systematic literature review

OBJECTIVE

This study aimed to investigate the correlation between genetic factors and the occurrence and progression of temporomandibular disorders (TMDs) using a comprehensive review and meta-analysis.

DESIGN

A comprehensive search was conducted using the ScienceDirect, PubMed, Cochrane Library, Dimensions, and Emerald databases. A reviewer selected the study using modified PICO criteria, considering human subjects with TMDs, comparing different genetic factors among TMD and non-TMD patients, and reporting TMD signs and symptoms as outcomes. The methodological standards of the eligible papers were assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Non-randomized Experimental Investigations. Information was collected methodically and examined.

RESULTS

The electronic database search yielded 851 articles, 19 of which were included in this study. The data analysis showed a significant influence of genetic factors, such as polymorphisms and gene differences, on the development of TMD signs and symptoms, such as myofascial pain, chronic pain, and disc displacement. In addition, gene polymorphism significantly influenced TMD development, with an odds ratio of 2.46 (1.93-3.14) and p of 0.00001.

CONCLUSIONS

Genetic factors significantly influenced TMD signs and symptoms, and genetic polymorphisms significantly influenced TMD onset and progression. Further research should be conducted in diverse settings with larger sample sizes to verify and validate these findings.

Therapeutic Potential of Downregulated Interleukin-6 Signaling for the Treatment of Chronic Pain: A Mendelian Randomization Study

Introduction

While numerous studies have emphasized the pivotal involvement of the Interleukin 6 (IL-6) pathway in the development of chronic pain, the causal nature of this relationship remains uncertain.

Methods

In this study, we opted to include genetic variants situated within the locus of the IL-6 receptor (IL-6R) that exhibited associations with C-reactive protein (CRP) levels. CRP serves as a downstream effector in the IL-6 pathway. Utilizing these variants as genetic proxies, we aimed to modulate IL-6 signaling. Employing a two-sample Mendelian randomization (MR) approach, we investigated the potential link between the genetic proxy and seven distinct subtypes of chronic pain, categorized based on their corresponding body locations. Moreover, we examined the relationship between chronic pain and an alternative instrument of IL-6 signaling that was weighted based on s-IL-6R levels. Furthermore, we conducted exploratory analyses to estimate the plausible causal association between CRP, gp130, and the subtypes of chronic pain.

Results

Our analysis showed that genetic proxied downregulation of IL-6 signaling, weighted on CRP levels, was linked to a reduced risk of chronic back and knee pain. The sensitivity analyses across various MR methods confirmed the consistency of the findings and showed no evidence of horizontal pleiotropy or heterogeneity. Moreover, the results remained robust with different sets of instrument variables. A genetically increased level of s-IL-6R was also negatively associated with chronic back and knee pain. However, there was no causal relationship between CRP and gp130 with chronic pain.

Conclusion

Based on our findings, there is evidence to suggest a potential causal relationship between IL-6 signaling and chronic back and knee pain. Consequently, the downregulation of IL-6 signaling holds promise as a potential therapeutic target for addressing chronic back and knee pain.