Catechol-O-methyltransferase (COMT) gene polymorphisms are associated with baseline disability but not long-term treatment outcome in patients with chronic low back pain

A preliminary study on the association of single nucleotide polymorphisms and methylation of dopamine system-related genes with psychotic symptoms in patients with methamphetamine use disorder

Methamphetamine use disorder (MAUD) can substantially jeopardize public security due to its high-risk social psychology and behaviour. Given that the dopamine reward system is intimately correlated with MAUD, we investigated the association of single nucleotide polymorphisms (SNPs), as well as methylation status of dopamine receptor type 4 (DRD4), catechol-O-methyltransferase (COMT) genes, and paranoid and motor-impulsive symptoms in MAUD patients. A total of 189 MAUD patients participated in our study. Peripheral blood samples were used to detect 3 SNPs and 35 CpG units of methylation in the DRD4 gene promoter region and 5 SNPs and 39 CpG units in the COMT gene. MAUD patients with the DRD4 rs1800955 C allele have a lower percentage of paranoid symptoms than those with the rs1800955 TT allele. Individuals with paranoid symptoms exhibited a reduced methylation degree at a particular DRD4 CpG2.3 unit. The interaction of the DRD4 rs1800955 C allele and the reduced DRD4CpG2.3 methylation degree were associated with a lower occurrence of paranoid symptoms. Meanwhile, those with the COMT rs4818 CC allele had lower motor-impulsivity scores in MAUD patients but greater COMT methylation levels in the promoter region and methylation degree at the COMT CpG 51.52 unit. Therefore, based only on the COMT rs4818 CC polymorphism, there was a negative correlation between COMT methylation and motor-impulsive scores. Our preliminary results provide a clue that the combination of SNP genotype and methylation status of the DRD4 and COMT genes serve as biological indicators for the prevalence of relatively high-risk psychotic symptoms in MAUD patients.

COMT and SCN9A gene variants do not contribute to chronic low back pain in Mexican-Mestizo patients

BACKGROUND

Chronic low back pain (CLBP) is a complex condition in which genetic factors play a role in its susceptibility. Catechol-O-methyltransferase (COMT) and sodium channel NaV1.7 (SCN9A) genes are implicated in pain perception. The aim is to analyze the association of COMT and SCN9A with CLBP and their interaction, in a Mexican-Mestizo population.

METHODS

A case-control study was conducted. Cases corresponded to adults of both sexes with CLBP. Controls were adults with no CLBP. Variants of SCN9A and COMT were genotyped. Allelic and genotypic frequencies and Hardy-Weinberg equilibrium (HWE) were calculated. Association was tested under codominant, dominant, and recessive models. Multifactor dimensionality reduction was developed to detect epistasis.

RESULTS

Gene variants were in HWE, and there was no association under different inheritance models in the whole sample. In women, in codominant and dominant models, a trend to a high risk was observed for AA of rs4680 of COMT (OR = 1.7 [0.5-5.3] and 1.6 [0.7-3.4]) and for TT of rs4633 (OR = 1.6 [0.7-3.7] and 1.6 [0.7-3.4]). In men, a trend to low risk was observed for AG genotype of rs4680 in the same models (OR = 0.6 [0.2-1.7] and 0.7 [0.3-1.7]), and for TC genotype of rs4633 in the codominant model (OR = 0.6 [0.2-1.7]). In the interaction analysis, a model of the SCN9A and COMT variants showed a CVC of 10/10; however, the TA was 0.4141.

CONCLUSION

COMT and SCN9A variants are not associated with CLBP in the analyzed Mexican-Mestizo population.

Challenges and opportunities for omics-based precision medicine in chronic low back pain

PURPOSE

Chronic low back pain (cLBP) is a common health condition worldwide and a leading cause of disability with an estimated lifetime prevalence of 80-90% in industrialized countries. However, we have had limited success in treating cLBP likely due to its non-specific heterogeneous nature that goes beyond detectable anatomical changes. We propose that omics technologies as precision medicine tools are well suited to provide insight into its pathophysiology and provide diagnostic markers and therapeutic targets. Therefore, in this review, we explore the current state of omics technologies in the diagnosis and classification of cLBP. We identify factors that may serve as markers to differentiate between acute and chronic cases of low back pain (LBP). Finally, we also discuss some challenges that must be overcome to successfully apply precision medicine to the diagnosis and treatment of cLBP.

METHODS

A literature search for the current applications of omics technologies to chronic low back pain was performed using the following search terms- "back pain," "low back pain," "proteomics," "transcriptomics", "epigenomics," "genomics," "omics." We reviewed molecular markers identified from 35 studies which hold promise in providing information regarding molecular insights into cLBP.

RESULTS

GWAS studies have found evidence for the role of single nucleotide polymorphisms (SNPs) associated with pain pathways in individuals with cLBP. Epigenomic modifications in patients with cLBP have been found to be enriched among genes involved in immune signaling and inflammation. Transcriptomics profiles of patients with cLBP show multiple lines of evidence for the role of inflammation in cLBP. The glycomics profiles of patients with cLBP are similar to those of patients with inflammatory conditions. Proteomics and microbiomics show promise but have limited studies currently.

CONCLUSION

Omics technologies have identified associations between inflammatory and pain pathways in the pathophysiology of cLBP. However, in order to integrate information across the range of studies, it is important for the field to identify and adopt standardized definitions of cLBP and control patients. Additionally, most papers have applied a single omics method to a sampling of cLBP patients which have yielded limited insight into the pathophysiology of cLBP. Therefore, we recommend a multi-omics approach applied to large global consortia for advancing subphenotyping and better management of cLBP, via improved identification of diagnostic markers and therapeutic targets.

HUMAN STUDY COMT and DRD3 haplotype-associated pain intensity and acute care utilization in adult sickle cell disease

A previous exploratory analysis of a COMT gene single-nucleotide polymorphism (SNP) and a DRD3 SNP by our group suggested possible contributions to pain-related acute care utilization in people with sickle cell disease (SCD). Our aim was to extend the analysis to gene-spanning haplotypes of COMT SNPs and DRD3 SNPs to investigate possible associations with pain intensity and pain-related acute care utilization in an SCD cohort. Genotyping was conducted, and clinical data were collected, including self-reported pain intensity using PAINReportIt^® (average of current pain and least and worst in past 24 hours, average pain intensity [API]) and medical record-extracted, pain-related acute care utilization data of 130 adults with SCD. Haplotype blocks were identified based on linkage disequilibria (COMT = 7 haploblocks; DRD3 = 8 haploblocks). Regression analyses were tested for association between haplotypes and API and utilization, yielding several significant findings. For COMT block 1 (rs2075507, rs4646310, rs737865), the A-G-G haplotype was associated with higher API compared to the reference A-G-A (p = 0.02), whereas the A-A-A haplotype was associated with higher utilization (p = 0.02). For DRD3 block 2 (rs9817063, rs2134655, rs963468, and rs3773679), relative to reference T-C-G-C, the T-T-G-C haplotype was associated with higher utilization (p = 0.01). For DRD3 block 4 (rs167770, rs324029, and rs324023), the A-G-T haplotype was associated with higher API (p = 0.04) and utilization (p < 0.001) relative to reference G-A-T, whereas the A-A-T haplotype was associated with higher utilization (p = 0.01). We found COMT and DRD3 haplotypes associated with pain-related SCD features, suggesting that in future studies more emphasis be placed on cis effects of SNP alleles in evaluating genetic contributions to SCD pain and acute care utilization for pain.

Multi-Site Observational Study to Assess Biomarkers for Susceptibility or Resilience to Chronic Pain: The Acute to Chronic Pain Signatures (A2CPS) Study Protocol

Chronic pain has become a global health problem contributing to years lived with disability and reduced quality of life. Advances in the clinical management of chronic pain have been limited due to incomplete understanding of the multiple risk factors and molecular mechanisms that contribute to the development of chronic pain. The Acute to Chronic Pain Signatures (A2CPS) Program aims to characterize the predictive nature of biomarkers (brain imaging, high-throughput molecular screening techniques, or "omics," quantitative sensory testing, patient-reported outcome assessments and functional assessments) to identify individuals who will develop chronic pain following surgical intervention. The A2CPS is a multisite observational study investigating biomarkers and collective biosignatures (a combination of several individual biomarkers) that predict susceptibility or resilience to the development of chronic pain following knee arthroplasty and thoracic surgery. This manuscript provides an overview of data collection methods and procedures designed to standardize data collection across multiple clinical sites and institutions. Pain-related biomarkers are evaluated before surgery and up to 3 months after surgery for use as predictors of patient reported outcomes 6 months after surgery. The dataset from this prospective observational study will be available for researchers internal and external to the A2CPS Consortium to advance understanding of the transition from acute to chronic postsurgical pain.

The genetic influence of the brain-derived neurotrophic factor Val66Met polymorphism in chronic low back pain

BACKGROUND

The Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene is a potential biomarker of vulnerability to pain. Thus, the present study aimed to investigate the association of this polymorphism with clinical and biopsychosocial factors in patients with chronic low back pain (CLBP).

METHODS

A total of 107 individuals with CLBP answered questionnaires that were validated and adapted for the Brazilian population, including the Brief Inventory of Pain, the Central Sensitization Inventory, the Roland Morris Disability Questionnaire, the Tampa Scale for Kinesiophobia, the Pain Catastrophizing Scale, the Survey of Pain Attitude-Brief, and the Hospital Anxiety and Depression Scale. All of the subjects were genotyped for the BDNF Val66Met polymorphism.

RESULTS

The sample showed moderate scores of disability, central sensitization, and kinesiophobia, in addition to mild anxiety, hopelessness, and ruminant thoughts. No significant association was observed between the Val66Met polymorphism and the variables analyzed. Besides, there was no relationship between the BDNF Val66Met polymorphism with CSI, catastrophization, or disabilities that were generated by CLBP.

CONCLUSION

The results showed that the Val66Met polymorphism of the BDNF gene was not associated with clinical and biopsychosocial characteristics of CLBP in the sample studied.

Can Implementation of Genetics and Pharmacogenomics Improve Treatment of Chronic Low Back Pain?

Etiology of back pain is multifactorial and not completely understood, and for the majority of people who suffer from chronic low back pain (cLBP), the precise cause cannot be determined. We know that back pain is somewhat heritable, chronic pain more so than acute. The aim of this review is to compile the genes identified by numerous genetic association studies of chronic pain conditions, focusing on cLBP specifically. Higher-order neurologic processes involved in pain maintenance and generation may explain genetic contributions and functional predisposition to formation of cLBP that does not involve spine pathology. Several genes have been identified in genetic association studies of cLBP and roughly, these genes could be grouped into several categories, coding for: receptors, enzymes, cytokines and related molecules, and transcription factors. Treatment of cLBP should be multimodal. In this review, we discuss how an individual's genotype could affect their response to therapy, as well as how genetic polymorphisms in CYP450 and other enzymes are crucial for affecting the metabolic profile of drugs used for the treatment of cLBP. Implementation of gene-focused pharmacotherapy has the potential to deliver select, more efficacious drugs and avoid unnecessary, polypharmacy-related adverse events in many painful conditions, including cLBP.

The Val158Met polymorphism of the catechol-O-methyltransference gene is not associated with long-term treatment outcomes in carpal tunnel syndrome: A randomized clinical trial

DESIGN

Randomized clinical trial.

OBJECTIVE

To investigate the association of the Val158Met polymorphism with pain and function outcomes in women with carpal tunnel syndrome (CTS) who received surgery or manual therapy including desensitization manoeuvres of the central nervous system.

METHODS

A pre-planned secondary analysis of a randomized controlled trial investigating the efficacy of manual therapy including desensitization manoeuvres of the central nervous system vs. surgery in 120 women with CTS was conducted. Women were randomized to receive 3 sessions of manual therapy (n = 60) or decompression of the carpal tunnel (n = 60). The primary outcome was intensity of pain (mean pain and the worst pain), and secondary outcomes included function and symptoms severity subscales of the Boston Carpal Tunnel Questionnaire. Outcomes were assessed at baseline, and 1, 3, 6, and 12 months after the intervention. Rs4680 genotypes were determined after amplifying the Val158Met polymorphism by polymerase chain reactions. We classified subjects according to their Val158Met polymorphism: Val/Val, Val/Met, or Met/Met. The primary aim (treatment group*Val158Met*time) was examined with repeated measures ANCOVA with intention-to-treat analysis.

RESULTS

At 12 months, 111 (92%) women completed the follow-up. No interaction was observed between the Val158Met genotype and any outcome: mean pain intensity (F = 0.60; P = 0.69), worst pain intensity (F = 0.49; P = 0.61), function (F = 0.12; P = 0.88) or symptom severity (F = 0.01; P = 0.98).

CONCLUSION

The current clinical trial did not show an association between the Val158Met polymorphism and changes in pain and function outcomes after either surgery or physical therapy in women with CTS.

A common polymorphism of COMT was associated with symptomatic lumbar disc herniation based on a large sample with Chinese Han ancestry

Lumbar disc herniation (LDH) is a common spine disease characterized by a tear in the disc ring and bulges out at the soft portion. COMT is a protein coding gene located at 22q11.21, and its gene product is a major mammalian enzyme involved in the degradation of catecholamines. A total of 2,678 study subjects with Chinese Han ancestry were recruited and 15 SNPs were selected for genotyping in our study subjects. A synonymous coding SNP, rs4633, was identified to be significantly associated with the disease status of LDH after adjusting for BMI (OR = 0.76, P = 4.83 × 10⁻⁵). This SNP was also identified to be significantly associated with COMT gene expression in three types of human tissues. Minor alleles of rs4633 (T) increased the expression of COMT in these 3 tissues. We have identified a significant SNP of COMT, rs4633, which is associated with symptomatic LDH in a large Chinese Han-based sample of the study subjects. This significant finding is further replicated by haplotypic analysis. Evidence from bioinformatics analyses have shown that rs4633 is also significantly associated with the gene expression of COMT. Our findings provide additional supportive evidence for an important role of COMT gene in the symptomatic LDH susceptibility.

Comorbidity of Alcohol Use Disorder and Chronic Pain: Genetic Influences on Brain Reward and Stress Systems

Alcohol use disorder (AUD) is highly comorbid with chronic pain (CP). Evidence has suggested that neuroadaptive processes characterized by reward deficit and stress surfeit are involved in the development of AUD and pain chronification. Neurological data suggest that shared genetic architecture associated with the reward and stress systems may contribute to the comorbidity of AUD and CP. This monograph first delineates the prevailing theories of the development of AUD and pain chronification focusing on the reward and stress systems. It then provides a brief summary of relevant neurological findings followed by an evaluation of evidence documented by molecular genetic studies. Candidate gene association studies have provided some initial support for the genetic overlap between AUD and CP; however, these results must be interpreted with caution until studies with sufficient statistical power are conducted and replications obtained. Genomewide association studies have suggested a number of genes (e.g., TBX19, HTR7, and ADRA1A) that are either directly or indirectly related to the reward and stress systems in the AUD and CP literature. Evidence reviewed in this monograph suggests that shared genetic liability underlying the comorbidity between AUD and CP, if present, is likely to be complex. As the advancement in molecular genetic methods continues, future studies may show broader central nervous system involvement in AUD-CP comorbidity.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

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.

Translating Genomic Advances to Physical Therapist Practice: A Closer Look at the Nature and Nurture of Common Diseases

The Human Genome Project and the International HapMap Project have yielded new understanding of the influence of the human genome on health and disease, advancing health care in significant ways. In personalized medicine, genetic factors are used to identify disease risk and tailor preventive and therapeutic regimens. Insight into the genetic bases of cellular processes is revealing the causes of disease and effects of exercise. Many diseases known to have a major lifestyle contribution are highly influenced by common genetic variants. Genetic variants are associated with increased risk for common diseases such as cardiovascular disease and osteoarthritis. Exercise response also is influenced by genetic factors. Knowledge of genetic factors can help clinicians better understand interindividual differences in disease presentation, pain experience, and exercise response. Family health history is an important genetic tool and encourages clinicians to consider the wider client-family unit. Clinicians in this new era need to be prepared to guide patients and their families on a variety of genomics-related concerns, including genetic testing and other ethical, legal, or social issues. Thus, it is essential that clinicians reconsider the role of genetics in the preservation of wellness and risk for disease to identify ways to best optimize fitness, health, or recovery. Clinicians with knowledge of the influence of genetic variants on health and disease will be uniquely positioned to institute individualized lifestyle interventions, thereby fulfilling roles in prevention and wellness. This article describes how discoveries in genomics are rapidly evolving the understanding of health and disease by highlighting 2 conditions: cardiovascular disease and osteoarthritis. Genetic factors related to exercise effects also are considered.