Influence of TNF-α-308 G/A gene polymorphism on temporomandibular disorder

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.

Genetic contributions to pain modulation in sickle cell: A focus on single nucleotide polymorphisms

Background

Despite recent advances in our knowledge of genetic contributions to the highly variable sickle cell disease (SCD) phenotype, our understanding of genetic factors associated with pain sensitivity in SCD remains limited. Previous studies investigated specific variants in single candidate genes and their association with SCD pain variability. The primary aim of the current study was to expand the genes and polymorphisms tested to discover new risk genes (polymorphisms) associated with central sensitization for individuals with SCD.

Methods

Adults with sickle cell disease (n = 59, Mage = 36.8 ± 11.5, 65.8 % female) underwent quantitative sensory testing to examine central sensitization and general pain sensitivity. Participants reported average crisis and non-crisis pain intensities weekly using a 0-100 scale, and provided salivary samples for genotyping. The Hardy-Weinberg equilibrium was verified for controls, and allele distributions were tested with chi-square and odds ratio tests. The Benjamini-Hochberg procedure was used to control for false discovery rate. Regression analyses and Wilcoxon tests were used to test associations for normally distributed and skewed data, respectively.

Results

Central sensitization and general pain sensitivity were not associated with hemoglobin genotype (Ps > 0.05). Of 4145 SNPs tested, following false discovery rate adjustments, 11 SNPs (rs11575839, rs12185625, rs12289836, rs1493383, rs2233976, rs3131787, rs3739693, rs4292454, rs4364, rs4678, rs6773307) were significantly associated with central sensitization, and one SNP (rs7778077) was significantly associated with average weekly non-crisis pain. No SNPs were associated with general pain sensitivity.

Conclusions

These findings provide insights into genetic variants association with average non-crisis pain and central sensitization for individuals with SCD, and may provide support for genetic predictors of heightened pain experience within SCD.

Estrogen Hormones' Implications on the Physiopathology of Temporomandibular Dysfunction

Background/Objectives: Temporomandibular dysfunction syndrome consists of several disorders of the masticatory system, namely those of the muscles, the joint itself, as well as the dental and periodontal system. This syndrome is often characterized by pain and an inability to perform functions within the dental-maxillary apparatus, which creates a certain degree of disability in patients. Women are more susceptible to this syndrome than men and hormonal factors, particularly estrogen, are central to its etiology and physiopathology. Methods: A comprehensive literature search was conducted using PubMed/MEDLINE, Scopus, Embase, and Web of Science databases regarding articles published from January 2008 to December 2023. Two authors conducted searches in the mentioned databases based on a pre-established search strategy using agreed-upon keywords. Additionally, each review author performed the selection process of eligible studies based on established inclusion criteria. The Newcastle-Ottawa scale and Risk of Bias tool 2 were used to assess each article for its methodological quality. Results: Of the 1030 records found in the four bibliographic databases, 22 studies were included in this review. Polymorphism in the alpha estrogen receptor appears to be significantly more prevalent in women with temporomandibular dysfunction, suggesting a genetic predisposition. There is a significant role of estrogen in the physiopathology of TMD-related pain. Women with polycystic ovary syndrome (PCOS) have a significantly higher incidence of TMD, accompanied by elevated inflammatory factors and decreased progesterone levels. In premenopausal women, there is scientific relevance to the association between beta-estradiol levels and TMD development and progression. The effects of estrogen hormones on temporomandibular dysfunction remain highly debated and challenging. Conclusions: These findings emphasize the importance of considering hormonal factors, genetic predisposition, and reproductive life stages in understanding and managing temporomandibular dysfunction. Further research is needed to elucidate the specific mechanisms underlying these associations.

Potential pathological and molecular mechanisms of temporomandibular joint osteoarthritis

Temporomandibular joint osteoarthritis (TMJ OA) is a progressive degenerative disease of the temporomandibular joint (TMJ). The unclear etiology and mechanisms of TMJ OA bring great difficulties to early diagnosis and effective treatment, causing enormous burdens to patients' life and social economics. In this narrative review, we summarized the main pathological changes of TMJ OA, including inflammatory responses, degeneration of extracellular matrix (ECM), abnormal cell biological behaviors (apoptosis, autophagy, and differentiation) in TMJ tissue, and aberrant angiogenesis. All pathological features are closely linked to each other, forming a vicious cycle in the process of TMJ OA, which results in prolonged disease duration and makes it difficult to cure. Various molecules and signaling pathways are involved in TMJ OA pathogenesis, including nuclear factor kappa-B (NF-κB), mitogen-activated protein kinases (MAPKs), extracellular regulated protein kinases (ERKs) and transforming growth factor (TGF)-β signaling pathways et al. One molecule or pathway can contribute to several pathological changes, and the crosstalk between different molecules and pathways can further lead to a complicated condition TMJ OA. TMJ OA has miscellaneous etiology, complex clinical status, depressed treatment results, and poor prognosis. Therefore, novel in-vivo and in-vitro models, novel medicine, materials, and approaches for therapeutic procedures might be helpful for further investigation of TMJ OA. Furthermore, the role of genetic factors in TMJ OA needs to be elucidated to establish more reasonable and effective clinical strategies for diagnosing and treating TMJ OA.

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

AIM

To verify the association of the TNF-α, IL-6, and IL-10 polymorphisms with chronic temporomandibular disorder pain development in female elderly patients.

METHODS

Participants were evaluated according to Diagnostic Criteria for Temporomandibular Disorders. The genomic DNA was extracted from blood according to the Salting Out method followed by a quantification using the NanoDrop spectrophotometer. The -308G/A TNF-α polymorphism analysis was performed by the polymerase chain reaction-restriction fragment length polymorphism technique, the determination of -174G/C IL-6 polymorphism was performed by polymerase chain reaction, and the evaluation of the -1082A/G IL-10 polymorphism was carried out by polymerase chain reaction- allele-specific amplification. Data were analyzed using the BioEstat 5.3 software.

RESULTS

The -308G/A TNF-α polymorphism showed a significant difference when genotypes of cases with chronic temporomandibular disorder pain and controls were compared (p = .025). There was a lack of association regarding the -174G/C IL-6 polymorphism (p = .286) however, a positive association between the -1082A/G IL-10 polymorphism with chronic temporomandibular disorder was observed (p = .020).

CONCLUSION

The analyzed data of elderly subjects support the possible involvement of the GA genotype of the -308G/A TNF-α and the AA genotype of the -1082A/G IL-10 polymorphisms in the pathogenesis of chronic temporomandibular disorder pain.

Genetic overlap between temporomandibular disorders and primary headaches: A systematic review

Primary headache disorders (PHD), specifically migraine, are strongly associated with temporomandibular disorders (TMD), sharing some patterns of orofacial pain. Both disorders have significant genetic contributions already studied. PRISMA guidelines were followed to conduct this systematic review, which comprehensively summarize and discuss the genetic overlap between TMD and PHD to aid future research in potential therapy targets. This review included eight original articles published between 2015 and 2020, written in English and related to either TMD and/or PHD. The genes simultaneously assessed in PHD and TMD studies were COMT, MTHFR, and ESR1. COMT was proved to play a critical role in TMD pathogenesis, as all studies have concluded about its impact on the occurrence of the disease, although no association with PHD was found. No proof on the impact of MTHFR gene regulation on either TMD or PHD was found. The most robust results are concerning the ESR1 gene, which is present in the genetic profile of both clinical conditions. This novel systematic review highlights not only the need for a clear understanding of the role of ESR1 and COMT genes in pain pathogenesis, but it also evaluates their potential as a promising therapeutic target to treat both pathologies.

TNF-α levels and presence of SNP-308G/A of TNF-α gene in temporomandibular disorder patients

INTRODUCTION

Temporomandibular disorder (TMD) refers to a group of conditions that compromise the harmonious movement and function of the temporomandibular joint, masticatory muscles, and associated structures. The etiopathogenesis of TMD is multifactorial but not well-understood, with the role of genetic factors still being unclear.

OBJECTIVE

This review aims to summarize the results of studies that evaluated TNF-α levels and the -308G/A TNF-α polymorphism in TMD patients. This study emphasizes the importance of a more selective treatment involving TNF-α inhibitors that can potentially reduce inflammation and pain, and improve quality of life.

METHODS

The MEDLINE/PubMed database, Cochrane Library, and Web of Science database were searched for case-control studies published until September 2020 that compared levels of TNF-α or presence of its -308G/A polymorphism in TMD patients and healthy individuals.

RESULTS

Six case-control studies were identified with a total of 398 TMD patients, aged between 12 and 78 years. The control group consisted of 149 subjects, aged between 18 and 47 years. The occurrence of TMD was predominant in females. Majority of studies found high TNF-α levels in TMD patients, compared to the control group. One of these studies found a positive correlation between the GA genotype and the development of TMD.

CONCLUSION

Majority of the TMD patients showed elevated TNF-α levels, and a possible explanation for this could be the presence of the -308G/A polymorphism.

Is there an association of genetic polymorphisms of the catechol-O-methyltransferase gene (rs165656 and rs174675) and the 5-hydroxytryptamine receptor 2A gene (rs4941573 and rs6313) with sleep bruxism in individuals with obstructive sleep apnea?

OBJECTIVE

To evaluate the association of single-nucleotide polymorphisms within the catechol-O-methyltransferase and 5-hydroxytryptamine receptor 2A genes with sleep bruxism in individuals diagnosed with obstructive sleep apnea.

DESIGN

Sixty-nine individuals with suspected sleep-related problems were evaluated by polysomnography, following the recommendations of the American Academy of Sleep Medicine. Deoxyribonucleic acid (DNA) samples were collected only from 48 of the study participants because of missing polysomnographic data. DNA samples were collected and two single-nucleotide polymorphisms in the 5-hydroxytryptamine receptor 2A encoding HTR2A gene (rs4941573 and rs6313) and two in the catechol-O-methyltransferase gene (rs165656 and rs174675) were selected to be genotyped using real-time polymerase chain reaction. The association between sleep bruxism and genetic polymorphisms was investigated by recessive and dominant models. Association analyses were performed using a 95% confidence interval and the level of statistical significance was p < 0.05.

RESULTS

From the 69 study participants, 48 were included in the polymorphism analysis and sleep bruxism was present in 35.4%. No significant differences were observed in the dominant and recessive models (p > 0.05). Haplotype and diplotype analyses revealed the predicted four haplotypes and two diplotypes were not associated with sleep bruxism.

CONCLUSION

Polymorphisms rs174675 and rs165656 in the catechol-O-methyltransferase gene and rs4941573 and rs6313 in the 5-hydroxytryptamine receptor 2A gene were not significantly associated with sleep bruxism in individuals with obstructive sleep apnea.

Chronic Orofacial Pain: Models, Mechanisms, and Genetic and Related Environmental Influences

Chronic orofacial pain conditions can be particularly difficult to diagnose and treat because of their complexity and limited understanding of the mechanisms underlying their aetiology and pathogenesis. Furthermore, there is considerable variability between individuals in their susceptibility to risk factors predisposing them to the development and maintenance of chronic pain as well as in their expression of chronic pain features such as allodynia, hyperalgesia and extraterritorial sensory spread. The variability suggests that genetic as well as environmental factors may contribute to the development and maintenance of chronic orofacial pain. This article reviews these features of chronic orofacial pain, and outlines findings from studies in animal models of the behavioural characteristics and underlying mechanisms related to the development and maintenance of chronic orofacial pain and trigeminal neuropathic pain in particular. The review also considers the role of environmental and especially genetic factors in these models, focussing on findings of differences between animal strains in the features and underlying mechanisms of chronic pain. These findings are not only relevant to understanding underlying mechanisms and the variability between patients in the development, expression and maintenance of chronic orofacial pain, but also underscore the importance for considering the strain of the animal to model and explore chronic orofacial pain processes.

Innate Immune and Neuronal Genetic Markers are Highly Predictive of Postoperative Pain and Morphine Patient-Controlled Analgesia requirements in Indian but not Chinese or Malay hysterectomy patients

OBJECTIVE

Pain severity and opioid requirements in the postoperative period show substantial and clinically significant inter-patient variation due mainly to factors such as age, surgery type and duration. Genetic factors have not been adequately assessed except for the neuronal OPRM1 rs1799971 and COMT rs4680, whereas the contribution of innate immune signalling pathway genetics was seldom investigated.

SETTING

Hospital surgical ward.

SUBJECTS

107 Indian, 184 Malay and 750 Han Chinese women undergoing total hysterectomy surgery.

METHODS

Morphine consumption, pre- and post-operative pain were evaluated in relation to genetic variability comprising 19 SNPs in 14 genes involved in glial activation, inflammatory signalling and neuronal regulation plus OPRM1 (1 SNP) and COMT (3 SNPs).

RESULTS

Pre- and post-operative pain and age were associated with increased and decreased morphine consumption, respectively. In Chinese patients, only 8% of the variability in consumption could be explained by these nongenetic and genetic (BDNF, IL1B, IL6R, CRP, OPRM1, COMT, MYD88) factors. However, in Indian patients, 41% of morphine consumption variability could be explained by age (explaining <3%) and variants in OPRM1 rs1799971, CRP rs2794521, TLR4 rs4986790, IL2 rs2069762, COMT rs4818, TGFB1 rs1800469 and IL6R rs8192284 when not controlling for postoperative pain.

CONCLUSIONS

This is the highest known value reported for genetic contributions (38%) to morphine use in the acute postoperative pain setting. Our findings highlight the need to incorporate both genetic and non-genetic factors and, consider ethnicity-dependent and non-additive genotypic models, when assessing factors that contribute to variability in opioid use.

Insights for temporomandibular disorders management: From psychosocial factors to genetics-A case report

AIMS

This case report aimed to discuss the multifactorial etiology and also the management of temporomandibular disorders (TMD) by addressing important associated psychosocial and biological factors, emphasizing the interaction between these factors and a probable genetic predisposition.

METHODS AND RESULTS

A 21-year-old female patient was evaluated according to Research Diagnostic Criteria for TMD and diagnosed with arthralgia, myofascial pain, disc displacement without reduction, and temporomandibular joint (TMJ) degenerative disease. TMJ alterations were confirmed through magnetic resonance imaging and cone-beam computed tomography. Pressure pain threshold of masticatory structures was evaluated using a pressure algometer. Sleep bruxism, poor sleep quality, migraine with aura, mild anxiety, and history of facial trauma were also identified through anamnesis and clinical examination. Following this, genetic analysis was performed to evaluate the presence of single nucleotide polymorphisms (SNPs) already associated with TMD: SNP COMT Val¹⁵⁸ Met (rs4680), MMP1-1607 (rs1799750), and tumor necrosis factor alpha-308 (rs1800629), which were all present. A personalized treatment for TMD management was performed, and it included self-management programs, occlusal appliance therapy, pharmacotherapy, anxiety management, and stress control. An 8-year follow-up demonstrated long-term stabilization of TMJ degenerative disease.

CONCLUSION

Genetic evaluation, added to anamnesis and clinical examination, could be useful for TMD prognosis and management.

Association of Estrogen Receptor 1 and Tumor Necrosis Factor α Polymorphisms with Temporomandibular Joint Anterior Disc Displacement without Reduction

Objectives

The aim of this study was to investigate the role of ESR1 rs1643821 and TNF-α rs1800629 as potential genetic factors regulating anterior disc displacement without reduction-mediated inflammatory pathway.

Background

The temporomandibular joint is a complex synovial joint that allows mandibular movement in three directions. Although temporomandibular disorders are widespread, limited data is available on the biochemical characteristics of the displaced disc and quality of the surrounding soft tissue. Changes in degenerative tissue provoke disc displacement which involves secretion of inflammatory markers and sequential conversion of fibroblast-like cells into chondrocyte-like cells. Due to the high occurrence in female adolescents, the potential role of sex hormones in temporomandibular joint disorders has been speculated. Furthermore, anterior disc displacement without reduction severely affects the quality of life.

Methods

124 Caucasian patients with a history of at least one anterior disc displacement without reduction within 3 months were enrolled. Anterior disc displacement without reduction was diagnosed based on clinical examination, diagnostic criteria (DC)/TMD, and cone-beam computed tomography/magnetic resonance imaging (CBCT/MRI). The control group consisted of 126 patients with no temporomandibular joint disorders. Genotyping of two single nucleotide polymorphisms, estrogen receptor 1 (ESR1) rs1643821, and tumor necrosis factor α (TNF-α) rs1800629 was performed.

Results

ESR1 rs1643821 showed significant P values (using chi-square analysis) revealing the difference in anterior disc displacement without reduction frequencies while TNF-α rs1800629 polymorphism was found to be statistically insignificant when compared to the control group. Furthermore, patients with a genotype of ESR1 rs1643821 showed a decreased probability (OR = 0.412) against anterior disc displacement without reduction when compared to the GG genotype (OR = 1).

Conclusion

ESR1 rs1643821 with A allele frequency was lower in patients with anterior disc displacement without reduction compared to the control group. Thus, the rs1643821 variant is significantly associated with susceptibility to the anterior disc displacement without a reduction in European Caucasians. Conversely, TNF-α rs1800629 was a statistically insignificant factor against anterior disc displacement without reduction when compared to the control group.

Role of inflammatory and pain genes polymorphisms in temporomandibular disorder and pressure pain sensitivity

OBJECTIVE

The aim of this study was to assess the correlation of inflammatory and pain genes polymorphisms with the presence of temporomandibular disorder (TMD) patients and with pressure pain sensitivity.

DESIGN

Data was collected from 268 consecutive subjects at Bauru School of Dentistry. Subjects aged younger than 20 years, with dental and neuropathic pain, sinusitis, cognitive and neurologic disorder were excluded. Included subjects were evaluated using the Research Diagnostic Criteria for Temporomandibular disorders and divided into two groups: TMD cases and healthy controls. Groups were submitted to pressure pain threshold (PPT) test for the temporomandibular joint, anterior temporalis and masseter muscles and genotyped for Val158Met, IL6-174, IL-1β-3954 and TNFA-308. Student's t-test and Pearson chi-square test were used to comparisons between groups. A linear multiple regression was used to evaluate the influence of genetics variables on the PPT and a bivariate analysis was used to assesses the influence of genetics variables on pain sensitivity below the PPT cut off of the structures in TMD group.

RESULTS

TMD group showed significantly lower PPT values for all structures when compared with control group (p < 0.001). SNP IL6-174 predicted higher pain sensitivity in the temporomandibular joint (p < 0.005) and in anterior temporalis muscle (p < 0.044) and SNP Val158Met in the masseter muscle (p < 0.038); when TMD group was divided according to PPT cut-off values the SNP Val158Met influenced increase pain sensibility in the masseter muscle.

CONCLUSION

TNFA-308 was associated with TMD and SNP IL6-174 and SNP Val158Met influenced pain sensitivity of patients with TMD.

Systematic Review and Meta-Analysis of Genetic Risk of Developing Chronic Postsurgical Pain

Chronic postsurgical pain (CPSP) is a significant detriment to postsurgical recovery and a risk factor for prolonged opioid use. Emerging evidence suggests the estimated heritability for chronic pain is 45% and that genetic factors partially explain individual susceptibility to CPSP. The aim of this study was to systematically review, assess quality, and summarize the studies in humans that have investigated genetic factors associated with CPSP. We also conducted a meta-analysis to derive a single effect size for evaluable genetic associations with CPSP. Our comprehensive literature search included review of 21 full-text articles evaluating variants of 69 genes for association with CPSP. We found significant gene variant associations reported for variants/haplotypes of 26 genes involved in neurotransmission, pain signaling, immune responses and neuroactive ligand-receptor interaction, with CPSP. Six variants of 5 genes (COMT: rs4680 and rs6269, OPRM1: rs1799971, GCH1: rs3783641, KCNS1: rs734784 and TNFA: rs1800629), were evaluated by more than one study and were included in the meta-analysis. At rs734784 (A>G) of KCNS1, presence of G allele marginally increased risk of CPSP (Additive genetic model; Odds ratio: 1.511; 95% CI 1-2.284; P value: .050), while the other variants did not withstand meta-analyses criteria. Our findings demonstrate the role of genetic factors with different functions in CPSP, and also emphasize that single genetic factors have small effect sizes in explaining complex conditions like CPSP. Heterogeneity in surgical cohorts, population structure, and outcome definitions, as well as small number of available studies evaluating same variants, limit the meta-analysis. There is a need for large-scale, homogenous, replication studies to validate candidate genes, and understand the underlying biological networks underpinning CPSP. PERSPECTIVE: Our systematic review comprehensively describes 21 studies evaluating genetic association with CPSP, and limitations thereof. A meta-analysis of 6 variants (5 genes) found marginally increased risk for CPSP associated with rs734784 A>G of the potassium voltage-gated channel gene (KCNS1). Understanding genetic predisposition for CPSP will enable prediction and personalized management.

The many faces of genetic contributions to temporomandibular joint disorder: An updated review

OBJECTIVES

The aim was to review the literature regarding genetic contributions to temporomandibular joint disorder (TMD) after our 2008 publication.

SETTING AND SAMPLE POPULATION

Literature review.

MATERIAL AND METHODS

PubMed and MEDLINE were used to obtain literature in any language regarding genes and TMD, using the keywords "temporomandibular joint disorder" and "temporomandibular joint dysfunction" for studies published from 2009 to 2017.

RESULTS

In our search, 274 studies were found. We excluded 76 studies from animal models, 22 studies that were in vitro and 120 reports that were not cohort or case-control studies. Of the 274 results, 56 articles were selected for this review. Genes that are suggested to contribute to TMD included the ones related to disc and bone alterations as well as pain sensation.

CONCLUSION

Currently, no evidence of associated genetic variants, which can determine the development of TMD in individuals, could be translated to novel clinical management and public health strategies for patients suffering from TMD.

Effect of a functional variant of tumor necrosis factor-β gene in temporomandibular disorders: A pilot study

BACKGROUND

Temporomandibular disorders (TMD) are a group of conditions that cause chronic orofacial pain. The tumor necrosis factor β (TNF-β) is a proinflammatory cytokine that is involved in the various aspects of the inflammatory process including organization and maintenance, and in the arrangement of cells at the inflammation site. The purpose of this study was to evaluate the correlation between TNF-β +252A/G (rs909253) variant and susceptibility to TMD in a Turkish cohort.

METHODS

The study included 104 patients (26 males, 78 females) with TMD and 126 healthy controls (44 males, 82 females). The TNF-β +252A/G variant analysis was based on Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP).

RESULTS

There was no deviation from HWA for TNF-β +252A/G variant in patient and control groups. There was significant difference in genotype and allele frequencies between patient group and control group in terms of TNF-β +252A/G variant, respectively (P = 0.010, 0.015). A significant increase in the TNF-β +252 AG genotype and G allele frequencies were observed in TMD patients compared to healthy controls. The individuals with GG genotype and G allele had an increased risk of developing TMD. A statistically significant association was observed when the patients were compared with the controls according to AA genotype vs AG+GG genotypes (P = 0.002, OR: 2.23, 95% CI:1.31-3.82). TNF-β +252A/G genotype distribution was associated with chewing problems (P = 0.046).

CONCLUSIONS

In conclusion, our results provided evidence that TNF-β +252A/G variant may contribute to TMD development in a Turkish cohort. Further studies are needed to confirm this observation.