COMT Gene Haplotypes Are Closely Associated with Postoperative Fentanyl Dose in Patients

SCN10A gene polymorphism is associated with pain sensitivity and postoperative analgesic effects in patients undergoing gynecological laparoscopy

BACKGROUND

Postoperative pain intensity is influenced by various factors, including genetic variations. The SCN10A gene encodes the Nav1.8 sodium channel protein, which is crucial for pain signal transmission in peripheral sensory neurons.

OBJECTIVES

This study aims to investigate the relationship between genetic mutations in the SCN10A gene (rs6795970) and postoperative analgesic effects following gynecological laparoscopic surgery.

METHODS

Two hundred female patients undergoing gynecological laparoscopic surgery under general anesthesia were included. pain sensitivity was evaluated using the catastrophizing scale and pain sensitivity questionnaire (PSQ). Patients received patient-controlled intravenous analgesia with sufentanil and dexmedetomidine for 48 h post-surgery. Postoperative pain indicators, such as visual analog scale (VAS) scores, Ramsay scores, and side effects were recorded. SCN10A rs6795970 mutations were identified using MassARRAY SNP typing technology, and patients were categoried into homozygous mutant (AA), wild type (GG), and heterozygous mutation (GA) groups for analysis.

RESULTS

Patients in the AA group had higher scores on the pain Catastrophizing Scale, PSQ-total, PSQ-minor, and PSQ-moderate compared to GA and GG groups (P < 0.05). VAS scores at 4, 6, and 12 h post-operation were higher in the AA group than the GG group (P < 0.05). Ramsay scores were lower in AA patients at 2 and 4 h post-operation compared to GA and GG groups (P < 0.05). The AA group exhibited more self-control analgesic pump compressions within the first 24 h post-surgery, quicker depletion of analgesics in the pump, and lower patient satisfaction with pain relief compared to GA and GG groups (P < 0.05).

CONCLUSIONS

Female patients with homozygous SCN10A mutations may experience higher preoperative pain scores and increased sensitivity to postoperative pain following gynecological laparoscopic surgery with intravenous patient-controlled analgesia.

TRIAL REGISTRATION

www.chictr.org.cn , registration number: ChiCTR2200062425.

Influence of COMT (rs4680) and OPRM1 (rs1799971) on Cancer Pain, Opioid Dose, and Adverse Effects

Background: The influence of pharmacogenomics on opioid response, particularly with COMT (rs4680) and OPRM1 (rs1799971) variants, has been studied individually and in combination. However, most studies are in a noncancer context and not all their possible variant combinations have been examined. Objectives: This study examined COMT (rs4680) and OPRM1 (rs1799971), and their allele combinations, in advanced cancer to examine associations with pain scores, opioid dose, and adverse effects. Setting/Subjects: This multicenter prospective cohort study recruited patients receiving opioids for advanced cancer pain in Melbourne, Australia. Clinical data (demographics, opioids), validated instruments (pain and adverse effects), and blood (DNA) were collected. Descriptive analyses were used. Univariate and multivariate logistic regression analyses were used to evaluate associations between clinical outcomes (opioid dose, pain, adverse effects) and genotypes of interest. Results: Fifty-four participants were recruited to the study. Those with COMT A allele required lower opioid doses [130 mg (interquartile range [IQR] 67.5,230) versus 180 mg (IQR 55,322.5), p = 0.047] and experienced greater adverse effects [sickness response aOR (adjusted odds ratio) 7.1 (95% CI 1.51,33.41), p = 0.01]. Those with the COMT GG/OPRM1 G allele combination required higher opioid doses [322.5 mg (IQR 264,360) versus 125 mg (65,225), (p = 0.04)]. Those with COMT AG/OPRM1 AA experienced higher average pain [aOR 1.55 (95% CI 1.03, 2.33), p = 0.04] and moderate-severe nausea [aOR 5.47 (95% CI 1.35, 22.21), p = 0.02] but reduced drowsiness [aOR 0.25 (95% CI 0.06, 1.02), p = 0.05]. Conclusions: Patients with cancer with the COMT alternate (A) allele have greater sickness response adverse effects, which may be responsible for the lower opioid doses observed. Significant results of two new COMT/OPRM1 genotype combinations are presented that have not previously been studied, with plausible phenotype descriptions suggested.

Genetic influence on treatment outcomes in patients with pain-related temporomandibular disorders

BACKGROUND

Single nucleotide polymorphisms (SNPs) may influence pain susceptibility and impact treatment response in pain-related temporomandibular disorders (TMDp).

OBJECTIVE

Explore the role of COMT (rs4646310, rs6269, rs4818, rs4680) and OPRM1 (rs1799971) genotypes in regulating treatment response.

METHODS

Sixty TMDp patients (55 females and 5 males), diagnosed with the Diagnostic Criteria for TMD (DC/TMD), underwent standardised treatment (information and education, home physical therapy, occlusal splint) for 6 months. Treatment outcomes included: pain intensity, pain-free mouth opening, jaw functional limitation, depression, and anxiety. Genotyping for COMT and OPRM1 SNPs was performed using DNA from buccal mucosa swabs and TaqMan assays. Statistical analysis was carried out to compare the changes in treatment outcomes and the influence of genotypes on treatment response.

RESULTS

Significantly less pain reduction was observed in minor allele carriers of rs4646310, and rs4680 compared to dominant homozygous (p < .025). Minor allele carriers of rs1799971 and rs4646310 demonstrated worsening in pain-free mouth opening while dominant homozygous exhibited improvement (p < .025). Significantly less anxiety reduction was observed in minor allele carriers of rs4646310 compared to dominant homozygous (p = .003). Of the all variables assessed in the regression model, carrying a minor allele of rs1799971 predicted a poorer treatment response considering pain-free mouth opening while carrying a minor allele of rs4646310 predicted less pain and less anxiety reduction.

CONCLUSION

Our findings indicate that certain SNP variants of the COMT and OPRM1 genes were associated with poorer treatment response and may therefore play a significant role in the classification of TMDp patients. Also, assessment of patient genotype could potentially aid in predicting treatment response.

Fentanyl dosage for preterm infants suggested by a pharmacokinetic, -dynamic, and -genetic model

BACKGROUND

Fentanyl is commonly administered for procedural pain management in preterm infants, but target concentrations have not yet been defined.

METHODS

To investigate pharmacokinetics (PK), -dynamics (PD), and -genetics (PG), 25 infants (gestational age 23.3-34.1 weeks) received a fentanyl dose before a skin-breaking procedure (0.5 µg/kg) or tracheal intubation (2 µg/kg). Four pain scales were used as a PD endpoint to evaluate efficacy. The impact of polymorphism in genes encoding enzymes (UGT2B7, CYP3A7, CYP3A4, COMT, CYP2D6, KCNJ6), transporters (SLC22A1, ABCC1, ABCC3) and receptor (OPRM1) on PK parameters was explored.

RESULTS

A two-compartment PK model adequately described the fentanyl concentration. The effects of weight and maturity on the clearance were included as covariates in the model. One genetic variant encoding the ABCC1 transporter (rs111517339 T/TA) and two encoding the ABCC3 transporter (rs11079921 T/C and rs8077268 C/T) had a significant effect on fentanyl elimination that explained 15% of the interindividual variability on the clearance. A proportional odds PK/PD model was used to describe the concentration-effect relationship of fentanyl using the Échelle de douleur et d'inconfort du nouveau-né (EDIN) pain score.

CONCLUSION

The simulations suggest that an intravenous dose of 2 µg/kg would be appropriate in preterm infants for a clearly painful procedure, such as an intubation.

IMPACT

Design of personalized analgesia with fentanyl for newborn infants should consider maturation and genetic variants of opioid transporters affecting drug elimination. The results indicate that an intravenous dose of 2 μg/kg fentanyl would be suitable before a clearly painful procedure in preterm infants. Genetic variants encoding ABCC1 and ABCC3 transporters increase the clearance of fentanyl, which is a novel finding.

Pharmacogenetic Approaches in Personalized Medicine for Postoperative Pain Management

Despite technical and pharmacological advancements in recent years, including optimized therapies and personalized medicine, postoperative pain management remains challenging and sometimes undertreated. This review aims to summarize and update how genotype-guided therapeutics within personalized medicine can enhance postoperative pain management. Several studies in the area have demonstrated that genotype-guided therapy has the ability to lower opioid consumption and improve postoperative pain. Gene mutations, primarily OPRM1, CYP2D6, CYP2C9, COMT and ABCB1, have been shown to exert nuanced influences on analgesic response and related pharmacological outcomes. This review underscores the integration of pharmacogenetic-guided personalized medicine into perioperative care, particularly when there is uncertainty regarding opioid prescriptions. This approach leads to superior outcomes in terms of postoperative pain relief and reduced morbidity for numerous patients.

Association of Genetic Variants with Postsurgical Pain: A Systematic Review and Meta-analyses

BACKGROUND

Postsurgical pain is a key component of surgical recovery. However, the genetic drivers of postsurgical pain remain unclear. A broad review and meta-analyses of variants of interest will help investigators understand the potential effects of genetic variation.

METHODS

This article is a systematic review of genetic variants associated with postsurgical pain in humans, assessing association with postsurgical pain scores and opioid use in both acute (0 to 48 h postoperatively) and chronic (at least 3 months postoperatively) settings. PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched from 2000 to 2022 for studies using search terms related to genetic variants and postsurgical pain in humans. English-language studies in adult patients examining associations of one or more genetic variants with postsurgical pain were included. The primary outcome was association of genetic variants with either acute or chronic postsurgical pain. Pain was measured by patient-reported pain score or analgesic or opioid consumption.

RESULTS

A total of 163 studies were included, evaluating 129 unique genes and 594 unique genetic variants. Many of the reported significant associations fail to be replicated in other studies. Meta-analyses were performed for seven variants for which there was sufficient data (OPRM1 rs1799971; COMT rs4680, rs4818, rs4633, and rs6269; and ABCB1 rs1045642 and rs2032582). Only two variants were associated with small differences in postsurgical pain: OPRM1 rs1799971 (for acute postsurgical opioid use standard mean difference = 0.25; 95% CI, 0.16 to 0.35; cohort size, 8,227; acute postsurgical pain score standard mean difference = 0.20; 95% CI, 0.09 to 0.31; cohort size, 4,619) and COMT rs4680 (chronic postsurgical pain score standard mean difference = 0.26; 95% CI, 0.08 to 0.44; cohort size, 1,726).

CONCLUSIONS

Despite much published data, only two alleles have a small association with postsurgical pain. Small sample sizes, potential confounding variables, and inconsistent findings underscore the need to examine larger cohorts with consistent outcome measures.

EDITOR’S PERSPECTIVE

Point-of-Care Testing of Enzyme Polymorphisms for Predicting Hypnotizability and Postoperative Pain

Hypnotizability is a stable trait that moderates the benefit of hypnosis for treating pain, but limited availability of hypnotizability testing deters widespread use of hypnosis. Inexpensive genotyping of four single-nucleotide polymorphisms in the catechol-o-methyltransferase (COMT) gene was performed using giant magnetoresistive biosensors to determine if hypnotizable individuals can be identified for targeted hypnosis referrals. For individuals with the proposed optimal COMT diplotypes, 89.5% score highly on the Hypnotic Induction Profile (odds ratio, 6.12; 95% CI, 1.26-28.75), which identified 40.5% of the treatable population. Mean hypnotizability scores of the optimal group were significantly higher than the total population (P = 0.015; effect size = 0.60), an effect that was present in women (P = 0.0015; effect size = 0.83), but not in men (P = 0.28). In an exploratory cohort, optimal individuals also reported significantly higher postoperative pain scores (P = 0.00030; effect size = 1.93), indicating a greater need for treatment.

Reviewing pharmacogenetics to advance precision medicine for opioids

BACKGROUND

Adequate opioid prescribing is critical for therapeutic success of pain management. Despite the widespread use of opioids, optimized opioid therapy remains unresolved with risk of accidental lethal overdosing. With the emergence of accumulating evidence linking genetic variation to opioid response, pharmacogenetic based treatment recommendations have been proposed.

OBJECTIVE

The aim of this review is to evaluate pharmacogenetic evidence and provide an overview on genes involved in the pharmacokinetics and pharmacodynamics of opioids.

METHODS

For this review, a systematic literature search of published articles was used in PubMed®, with no language restriction and between the time period of January 2000 to December 2020. We reviewed randomized clinical studies, study cohorts and case reports that investigated the influence of genetic variants on selected opioid pharmacokinetics and pharmacodynamics. In addition, we reviewed current CPIC clinical recommendations for pharmacogenetic testing.

RESULTS

Results of this review indicate consistent evidence supporting the association between selected genetic variants of CYP2D6 for opioid metabolism. CPIC guidelines include recommendations that indicate the avoidance of tramadol use, in addition to codeine, in CYP2D6 poor metabolizers and ultrarapid metabolizers, and to monitor intermediate metabolizers for less-than-optimal response. While there is consistent evidence for OPRM1 suggesting increased postoperative morphine dosing requirements in A118G G-allele carriers, the clinical relevance remains limited.

CONCLUSION

There is emerging evidence of clinical relevance of CYP2D6 and, to a lesser extent, OPRM1 polymorphism in personalized opioid drug dosing. As a result, first clinics have started to implement pharmacogenetic guidelines for CYP2D6 and codeine.

Pharmacogenomics in Pain Management: A Review of Relevant Gene-Drug Associations and Clinical Considerations

OBJECTIVE

To provide an overview of clinical recommendations regarding genomic medicine relating to pain management and opioid use disorder.

DATA SOURCES

A literature review was conducted using the search terms pain management, pharmacogenomics, pharmacogenetics, pharmacokinetics, pharmacodynamics, and opioids on PubMed (inception to February 1, 2021), CINAHL (2016 through February 1, 2021), and EMBASE (inception through February 1, 2021).

STUDY SELECTION AND DATA EXTRACTION

All relevant clinical trials, review articles, package inserts, and guidelines evaluating applicable pharmacogenotypes were considered for inclusion.

DATA SYNTHESIS

More than 300 Food and Drug Administration-approved medications contain pharmacogenomic information in their labeling. Genetic variability may alter the therapeutic effects of commonly prescribed pain medications. Pharmacogenomic-guided therapy continues to gain traction in clinical practice, but a multitude of barriers to widespread pharmacogenomic implementation exist.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Pain is notoriously difficult to treat given the need to balance safety and efficacy when selecting pharmacotherapy. Pharmacogenomic data can help optimize outcomes for patients with pain. With improved technological advances, more affordable testing, and a better understanding of genomic variants resulting in treatment disparities, pharmacogenomics continues to gain popularity. Unfortunately, despite these and other advancements, pharmacogenomic testing and implementation remain underutilized and misunderstood in clinical care, in part because of a lack of health care professionals trained in assessing and implementing test results.

CONCLUSIONS

A one-size-fits-all approach to pain management is inadequate and outdated. With increasing genomic data and pharmacogenomic understanding, patient-specific genomic testing offers a comprehensive and personalized treatment alternative worthy of additional research and consideration.

OPRM1 and COMT polymorphisms: implications on postoperative acute, chronic and experimental pain after cardiac surgery

Aim: Investigate the potential role of OPRM1 (mu-opioid receptor) and COMT (catechol-O-methyltransferase enzyme) polymorphisms in postoperative acute, chronic and experimental thermal pain. Methods: A secondary analysis of 125 adult cardiac surgery patients that were randomized between fentanyl and remifentanil during surgery and genotyped. Results: Patients in the fentanyl group with the COMT high-pain sensitivity haplotype required less postoperative morphine compared with the average-pain sensitivity haplotype (19.4 [16.5; 23.0] vs 34.6 [26.2; 41.4]; p = 0.00768), but not to the low-pain sensitivity group (30.1 [19.1; 37.7]; p = 0.13). No association was found between COMT haplotype and other pain outcomes or OPRM1 polymorphisms and the different pain modalities. Conclusion: COMT haplotype appears to explain part of the variability in acute postoperative pain in adult cardiac surgery patients.

Pharmacogenomics, concepts for the future of perioperative medicine and pain management: A review

Pharmacogenomics is the study of how genetic differences between individuals affect pharmacokinetics and pharmacodynamics. These differences are apparent to clinicians when taking into account the wide range of responses to medications given in clinical practice. A review of literature involving pharmacogenomics and pain management was performed. The implementation of preoperative pharmacogenomics will allow us to better care for our patients by delivering personalized, safer medicine. This review describes the current state of pharmacogenomics as it relates to many aspects of clinical practice and how clinicians can use these tools to improve patient outcomes.

Genetic Polymorphisms of Cytokines Might Affect Postoperative Sufentanil Dosage for Analgesia in Patients

Objective

To explore the effect of genetic polymorphisms of cytokines on the dosage of sufentanil for patient-controlled intravenous analgesia (PCIA) after radical lung cancer surgery.

Methods

A total of 100 patients, aged 18 years and above, with ASA grade Ⅰ-Ⅱ and body mass index (BMI) 18.5 to 30, and who were scheduled for radical lung cancer surgery under total intravenous anaesthesia with PCIA of sufentanil from September 2015 to March 2016, were selected. DNA was collected from peripheral blood samples before surgery, and the iMLDRTM multiple single-nucleotide polymorphism typing kit was used to detect 16 related single-nucleotide polymorphism (SNP) sites of interleukin-1A (IL-1A), interleukin-1β (IL-1β), interleukin-1RN (IL-1RN), interleukin-6 (IL-6), C-X-C motif chemokine ligand 8 (CXCL8), interleukin-10 (IL-10), tumour necrosis factor (TNF), nuclear factor kappa-B1 (NFκB1), REL (REL proto-oncogene, NF-kB subunit), and nuclear factor kappa-B inhibitor alpha (NFκBIA). The general characteristics of patients, surgery and anaesthesia data, postoperative resting VAS pain scores, postoperative opioid dosages of sufentanil for PCIA and opioid-related adverse events were recorded. The effects of the examined genetic polymorphisms of the cytokines on the dosage of sufentanil were analysed.

Results

Eight of 100 patients withdrew for various reasons, and, eventually, 92 patients were included. The patients’ resting visual analogue scale (VAS) scores at 24 h, 48 h, and 72 h after surgery were 2.3 ± 1.2, 2.0 ± 0.9, and 1.9 ± 1.0, respectively. The total amounts of sufentanil used were 34.7 ± 10.5 μg, 65.2 ± 13.7 μg, and 94.7 ± 11.6 μg, respectively. We found that the TT genotype of NFκBIA rs696 had higher PCIA sufentanil dosages than the CC genotype and the CT genotype at 48–72 h postoperation (p=0.023, p=0.025, respectively).

Conclusion

The genetic polymorphisms of the cytokine NFκBIA rs696 might affect the dosage of sufentanil for PCIA after radical lung cancer surgery. The specific mechanism needs further study.

Pharmacogenomics of Pain Management: The Impact of Specific Biological Polymorphisms on Drugs and Metabolism

PURPOSE OF REVIEW

Pain is multifactorial and complex, often with a genetic component. Pharmacogenomics is a relative new field, which allows for the development of a truly unique and personalized therapeutic approach in the treatment of pain.

RECENT FINDINGS

Until recently, drug mechanisms in humans were determined by testing that drug in a population and calculating response averages. However, some patients will inevitably fall outside of those averages, and it is nearly impossible to predict who those outliers might be. Pharmacogenetics considers a patient's unique genetic information and allows for anticipation of that individual's response to medication. Pharmacogenomic testing is steadily making progress in the management of pain by being able to identify individual differences in the perception of pain and susceptibility and sensitivity to drugs based on genetic markers. This has a huge potential to increase efficacy and reduce the incidence of iatrogenic drug dependence and addiction. The streamlining of relevant polymorphisms of genes encoding receptors, transporters, and drug-metabolizing enzymes influencing the pain phenotype can be an important guide to develop safe new strategies and approaches to personalized pain management. Additionally, some challenges still prevail and preclude adoption of pharmacogenomic testing universally. These include lack of knowledge about pharmacogenomic testing, inadequate standardization of the process of data handling, questionable benefits about the clinical and financial aspects of pharmacogenomic testing-guided therapy, discrepancies in clinical evidence supporting these tests, and doubtful reimbursement of the tests by health insurance agencies.

Single nucleotide polymorphisms associated with postoperative inadequate analgesia after single-port VATS in Chinese population

Background

Postoperative inadequate analgesia following video-assisted thoracoscopic surgery (VATS) is a common and significant clinical problem. While genetic polymorphisms may play role in the variability of postoperative analgesia effect, few studies have evaluated the associations between genetic mutations and inadequate analgesia after single-port VATS.

Methods

Twenty-eight single nucleotide polymorphisms (SNPs) among 18 selected genes involved in pain perception and modulation were genotyped in 198 Chinese patients undergoing single-port VATS. The primary outcome was the occurrence of inadequate analgesia in the first night and morning after surgery which was defined by a comprehensive postoperative evaluation. Multivariable logistic regression analyses were used to identify the association between genetic variations and postoperative inadequate analgesia.

Results

The prevalence of postoperative inadequate analgesia was 45.5% in the present study. After controlling for age and education level, association with inadequate analgesia was observed in four SNPs among three genes encoding voltage-gated sodium channels. Patients with the minor allele of rs33985936 (SCN11A), rs6795970 (SCN10A), and 3312G > T (SCN9A) have an increased risk of suffering from inadequate analgesia. While the patients carrying the minor allele of rs11709492 (SCN11A) have lower risk experiencing inadequate analgesia.

Conclusions

We identified that SNPs in SCN9A, SCN10A, and SCN11A play a role in the postoperative inadequate analgesia after single-port VATS. Although future larger and long-term follow up studies are warranted to confirm our findings, the results of the current study may be utilized as predictors for forecasting postoperative analgesic effect for patients receiving this type of surgery.

Trial registration

This study was retrospectively registered in the ClinicalTrials.gov Registry (NCT03916120) on April 16, 2019.

Gender based differences, pharmacogenetics and adverse events in chronic pain management

Safety data in chronic non-cancer pain (CNCP) with long-term opioid therapy has been poorly studied and can be differently influenced by gender. Furthermore, pharmacogenetics (PGx) could possibly be used to tailor pain medication based on the individual's genetic background. The aim was to assess whether PGx applied to a pharmacovigilance system could help to improve a patient's security profile. A pharmacovigilance data recording system was conducted over 24 months, including genotyping of OPRM1 variants (opioid receptor, A118G) and COMT (enzyme that degrades catecholamines such as norepinephrine, G1947A). Pain intensity (visual analogue scale, VAS), morphine equivalent daily dose (MEDD), adverse events (AEs) and suspected adverse drug reactions (ADRs) were recorded and analysed by gender. The Ethics Committee approved the study and data were analysed with R 3.6.0 software. A total of 748 patients were recruited in the study (67% female, VAS 62 ± 29 mm, MEDD 119 ± 114 mg/day) reporting a median of 6 (3.5-9) AEs/patient. Women presented more nausea, headaches, insomnia, loss of appetite, weight change, depression and dizziness than men. Analysis by genotype demonstrated that PGx influenced the prevalence of vomiting and depression in men, dizziness in women and sexual dysfunction in both. Physicians notified 150 ADRs mostly in females (79%) related to nervous system disorders. PGx applied to a pharmacovigilance recording system provides important information to achieve a better knowledge about AEs in CNCP pharmacological therapy. OPRM1 and COMT polymorphisms were associated with AEs in CNCP patients that differed according to gender.

Fentanyl overdoses and pharmacogenetics

Fentanyl has been implicated as a major contributor to the increased number of opioid overdose deaths. Surprisingly, little is known about the pharmacogenetic influences on fentanyl pharmacokinetics or pharmacodynamics. Pharmacogenetic studies of fentanyl are based largely on small sample sizes and have examined the potential association of only a small number of high frequency variants in selected candidate genes primarily with postoperative pain. Few data are available on low frequency variants, variants from racially/ethnically diverse populations, or on other phenotypes. Given the genetic diversity of low frequency variants, DNA sequencing may be needed to determine whether pharmacogenetic differences may contribute to lethal opioid overdoses.

Systems pharmacogenomics - gene, disease, drug and placebo interactions: a case study in COMT

Disease, drugs and the placebos used as comparators are inextricably linked in the methodology of the double-blind, randomized controlled trial. Nonetheless, pharmacogenomics, the study of how individuals respond to drugs based on genetic substrate, focuses primarily on the link between genes and drugs, while the link between genes and disease is often overlooked and the link between genes and placebos is largely ignored. Herein, we use the example of the enzyme catechol-O-methyltransferase to examine the hypothesis that genes can function as pharmacogenomic hubs across system-wide regulatory processes that, if perturbed in andomized controlled trials, can have primary and combinatorial effects on drug and placebo responses.

Association of COMT gene variability with pain intensity in patients after total hip replacement

Pain is one of the most interdisciplinary clinical symptoms of a disease. The aim of the study was to evaluate the association of COMT gene polymorphism with pain perception in patients after total hip replacement (THR). The study included 195 patients qualified for surgical treatment (THR) due to osteoarthritis. Patients previously undergoing hip replacement subsequently underwent multimodal pain management therapy, in accordance with the recommendations for treating postoperative pain. The intensity of pain was measured three times at pre-defined time intervals: 1.5, 6 and 12 months after hip replacement, using the visual analogue scale. Single nucleotide polymorphism (SNP) in the COMT gene rs4680: A>G (Val158Met), rs6269: A>G (promoter region), rs4633: C>T (His62His) and rs4818: C>G (Leu136Leu) was genotyped. COMT SNP frequency distribution was analysed. For rs6269 and rs4818, the minor allele was the G allele (38.7 and 38.5%, respectively). It was also observed that rs4633 (T) allele frequency (50%) equalled that of the rs4680 (A) allele (50%). We assessed COMT haplotype frequency in the patients studied. The most frequent haplotype was haplotype M (ATCA) (50%), the rarest haplotype was haplotype R (ATGG), with a frequency of 0.3%. The most frequent diplotype was H/M, which was found in 37.95% of the patients. The frequency of other diplotypes was: M/M-24.10%, H/H-15.90% and L/M-13.33%. The study showed a significant association of rs4818 G allele and equivalent COMT H haplotype with lower sensitivity to pain after hip replacement.

Candidate gene analyses for acute pain and morphine analgesia after pediatric day surgery: African American versus European Caucasian ancestry and dose prediction limits

Acute pain and opioid analgesia demonstrate inter-individual variability and polygenic influence. In 241 children of African American and 277 of European Caucasian ancestry, we sought to replicate select candidate gene associations with morphine dose and postoperative pain and then to estimate dose prediction limits. Twenty-seven single-nucleotide polymorphisms (SNPs) from nine genes (ABCB1, ARRB2, COMT, DRD2, KCNJ6, MC1R, OPRD1, OPRM1, and UGT2B7) met selection criteria and were analyzed along with TAOK3. Few associations replicated: morphine dose (mcg/kg) in African American children and ABCB1 rs1045642 (A allele, β = -9.30, 95% CI: -17.25 to -1.35, p = 0.02) and OPRM1 rs1799971 (G allele, β = 23.19, 95% CI: 3.27-43.11, p = 0.02); KCNJ6 rs2211843 and high pain in African American subjects (T allele, OR 2.08, 95% CI: 1.17-3.71, p = 0.01) and in congruent European Caucasian pain phenotypes; and COMT rs740603 for high pain in European Caucasian subjects (A allele, OR: 0.69, 95% CI: 0.48-0.99, p = 0.046). With age, body mass index, and physical status as covariates, simple top SNP candidate gene models could explain theoretical maximums of 24.2% (European Caucasian) and 14.6% (African American) of morphine dose variances.

Genomics Testing and Personalized Medicine in the Preoperative Setting

Pharmacogenomics (PGx) is the study of how individuals' personal genotypes may affect their responses to various pharmacologic agents. The application of PGx principles in perioperative medicine is fairly novel. Challenges in executing PGx programs into health care systems include physician buy-in and integration into usual clinical workflow, including the electronic health record. This article discusses the current evidence highlighting the potential of PGx with various drug categories (including opioids, nonopioid analgesics, sedatives, β-blockers, antiemetics, and anticoagulants) used in the perioperative process and the challenges of integrating PGx into a health care system and relevant workflows.

Clinical and pharmacogenetics associated with recovery time from general anesthesia

AIM

Delayed recovery from general anesthesia is a well-known complication that requires predictive tools and approaches. This study aimed to determine significant factors associated with postanesthesia recovery and to develop an algorithm for estimating recovery time from general anesthesia.

MATERIALS & METHODS

The genotypes of patients were determined by SNaPshot or ARMS-qPCR. The algorithm was developed via machine-learning and tested by the worm plot.

RESULTS

Results showed that OPRM1 rs1799971 (p = 0.006) and ABCG2 rs2231142 (p = 0.041) were significantly associated with recovery time. Ten factors after random forest and stepwise selection were associated with recovery time. Ten factors after random forest and stepwise selection were associated with recovery time. Meanwhile, seven factors were associated with delayed recovery.

CONCLUSION

This study demonstrated that both clinical and pharmacogenetic data are significantly associated with recovery from general anesthesia and provide the basis for pre-emptive prediction tools.

The Role of Genetic Polymorphisms in Chronic Pain Patients

It is estimated that the total annual financial cost for pain management in the U.S. exceeds 100 billion dollars. However, when indirect costs are included, such as functional disability and reduction in working hours, the cost can reach more than 300 billion dollars. In chronic pain patients, the role of pharmacogenetics is determined by genetic effects on various pain types, as well as the genetic effect on drug safety and efficacy. In this review article, we discuss genetic polymorphisms present in different types of chronic pain, such as fibromyalgia, low back pain, migraine, painful peripheral diabetic neuropathy and trigeminal neuralgia. Furthermore, we discuss the role of CYP450 enzymes involved in metabolism of drugs, which have been used for treatment of chronic pain (amitriptyline, duloxetine, opioids, etc.). We also discuss how pharmacogenetics can be applied towards improving drug efficacy, shortening the time required to achieve therapeutic outcomes, reducing risks of side effects, and reducing medical costs and reliance upon polypharmacy.

Pharmacogenomics in Pain Management

There is interpatient variability to analgesic administration. Much can be traced to pharmacogenomics variations between individuals. Certain ethnicities are more prone to reduced function of CYP2D6. Weak opioids are subject to interpatient variation based on their CYP2D6 type. Strong opioids have variations based on their transport and individual metabolism. Several cytochrome enzymes have been found to be involved with ketamine but there is no strong evidence of individual polymorphisms manifesting in clinical outcomes. Nonsteroidal anti-inflammatory drugs have adverse outcomes that certain CYP variants are more prone toward. There are now recommendations for dosing based on specific genomic makeup.

Roles of functional catechol-O-methyltransferase genotypes in Chinese patients with Parkinson's disease

Background

Recent studies have found that the functional catechol-O-methyltransferase (COMT) gene may be associated with the susceptibility to and pharmacotherapy of Parkinson’s disease (PD). In this case–control study, we investigated the most common functional COMT gene haplotypes that had been shown to influence COMT enzymatic activity and the association of the single and combined COMT haplotypes with clinical symptoms and pharmacotherapy in Chinese patients with PD.

Methods

One hundred forty-three patients with idiopathic PD and 157 healthy individuals were enrolled in this study. Four single nucleotide polymorphisms (SNPs) in the COMT gene (formed by SNPs) were genotyped in each participant: rs6269 A > G; rs4633 C > T; rs4818 C > G; and rs4680 G > A.

Results

The frequencies of rs4633 T carriers, rs4680 A carriers and the two linked rs4633-rs4680 T/A carriers were significantly higher in the early onset PD group than in the healthy controls (all P < 0.05). Homozygosity for rs4633 (TT), rs4680 (AA) and of the two linked rs4633-rs4680 (TT/AA) was significantly more frequent in patients who exhibited the “wearing-off” phenomenon, longer disease duration, higher levodopa equivalent doses (LED) and higher Unified Parkinson’s Disease Rating Scale (UPDRS) scores (P < 0.05). No significant differences were observed in the clinical features of patients who carried individual rs6269 and rs4818, the two linked rs6269-rs4818 and the four combined COMT SNPs.

Conclusions

The results showed a possible association of combined functional COMT SNPs with PD risk, disease duration, the “wearing-off” phenomenon, daily LEDs and higher UPDRS scores, which may be useful in instituting individualized therapy for patients with PD.

Electronic supplementary material

The online version of this article (doi:10.1186/s40035-017-0081-9) contains supplementary material, which is available to authorized users.

A Novel Sensitive Method to Measure Catechol-O-Methyltransferase Activity Unravels the Presence of This Activity in Extracellular Vesicles Released by Rat Hepatocytes

There is a clear need for drug treatments to be selected according to the characteristics of an individual patient, in order to improve efficacy and reduce the number and severity of adverse drug reactions. One of the main enzymes to take into account in pharmacogenomics is catechol O-methyltransferase (COMT), which catalyzes the transfer of a methyl group from S-adenosylmethionine to catechols and catecholamines, like the neurotransmitters dopamine, epinephrine, and norepinephrine. Although, most of this enzyme is associated to intracellular vesicles, recently it has also been detected in extracellular vesicles secreted by hepatocytes and in serum circulating vesicles. COMT has implications in many neurological and psychiatric disorders like Parkinson's disease, chronic fatigue, pain response, schizophrenia, and bipolar disorders. Remarkably, genetic variations of COMT affect its activity and are associated to various human disorders from psychiatric diseases to estrogen-induced cancers. Consequently, the establishment of new methods to evaluate COMT activity is an important aspect to investigate the biology of this drug-metabolizing enzyme. Herein, we have developed a sensitive and selective method to determine COMT activity. We first optimized the activity in rat liver incubated with two different substrates; norepinephrine and dopamine. The enzymatically formed products (normetanephrine and 3-methoxytyramine, respectively) were extracted by solid-phase extraction using weak cation exchange cartridges, chromatographically separated, and detected and quantified using a mass spectrometer. The range of quantitation for both products was from 0.005 to 25 μg/mL. This methodology offers acceptable recovery for both enzymatic products (≥75%) and good accuracy and precision (≤15%). The lower limit of quantifications were 0.01 and 0.005 μM for 3-methoxytyramine and normetanephrine, respectively. Importantly, this sensitive assay was able to detect the presence of COMT activity in extracellular vesicles secreted by hepatocytes supporting a potential role of these vesicles in catecholamines and catecholestrogens metabolisms. In addition, the presence of COMT activity in extracellular vesicles opens new possibilities to develop tools to evaluate personalized drug response in a low invasive manner.

OPRM1 and COMT Gene-Gene Interaction Is Associated With Postoperative Pain and Opioid Consumption After Orthopedic Trauma

BACKGROUND

mu-opioid receptor ( OPRM1) and catechol-O-methyltransferase ( COMT) contribute to the neurotransmission pathway of pain. COMT affects mu receptor expression and density in the brain. The aim of this study was to explore the OPRM1 and COMT interaction effects on postoperative pain and opioid consumption.

METHODS

This cross-sectional exploratory study used genotype and clinical data from 153 postoperative patients. Using multiple regression analyses, four single-nucleotide polymorphisms of COMT (rs6269, rs4633, rs4818, and rs4680), their haplotypes, and diplotypes were considered for their interactions with A118G of OPRM1 regarding postoperative pain and opioid consumption.

RESULTS

For opioid consumption, significant interactions were found between OPRM1 A118G and COMT rs4680 ( p = .037) and between OPRM1 and COMT rs4633 ( p = .037). Patients having Met158Met of COMT rs4680 and AG/GG of OPRM1 or TT of COMT rs4633 and AG/GG of OPRM1 consumed the largest amount of opioid compared to those having other combinations. For postoperative pain, a significant interaction was found between OPRM1 and the low pain sensitivity (LPS; GCGG) haplotype of COMT ( p = .017). For patients with no copies of the LPS haplotype, AA of OPRM1 A118G was significantly associated with higher pain scores compared to the variant AG/GG. However, the opposite direction was observed for patients with at least one copy of the LPS haplotype.

CONCLUSIONS

The interaction of OPRM1 with COMT may contribute to variability in postoperative pain and opioid consumption. Additional larger studies are needed to confirm findings.

Opioid treatment failure in cancer patients: the role of clinical and genetic factors

AIM

To identify clinical and genetic factors associated with outcome of opioid treatment.

PATIENTS & METHODS

We performed an exploratory analysis in a cohort of 353 patients treated with fentanyl, morphine, oxycodone and/or hydromorphone for cancer-related pain, exploring selected clinical and pharmacogenetic factors for a correlation with treatment failure for all and per type of opioid.

RESULTS

Use of adjuvant pain medication, intensity of pain at rest and age were associated with treatment failure in the various cohorts. Only the genetic variants rs12948783 (RHBDF2) and rs7016778 (OPRK1) correlated statistically significant in univariate, but not in multivariable analysis.

CONCLUSION

Several clinical and genetic factors were identified that warrant further study to clarify their role and use in opioid treatment.

Personalizing supportive care in oncology patients using pharmacogenetic-driven treatment pathways

Cancer patients frequently suffer from disease- and treatment-related pain, nausea and depression, which severely reduces patients' quality of life. It is critical that clinicians are aware of drug-gene interactions and recognize the utility of applying pharmacogenetic information to personalize and improve supportive care. Pharmacogenetic-based algorithms may enhance clinical outcomes by allowing the clinician to select the 'least genetically vulnerable' drug. This review summarizes clinically relevant drug-gene interactions and presents pharmacogenetic-driven treatment pathways for depression, nausea/vomiting and pain. Ideally, this review provides a resource for clinicians to consult when selecting pharmacotherapy for a patient who presents with limited pharmacogenetic test results, with the hope of better controlling burdensome symptoms and improving the quality of life for cancer patients.

Association between catechol-O-methyl transferase gene polymorphisms and fibromyalgia in a Korean population: A case-control study

BACKGROUND

Although polymorphisms of the catechol-O-methyl transferase (COMT) gene have been implicated in altered pain sensitivity, results concerning the association between COMT gene polymorphisms and fibromyalgia (FM) are equivocal. We assessed the associations between COMT single-nucleotide polymorphisms (SNP) and FM risk and symptom severity.

METHODS

In total, 409 FM patients and 423 controls were enrolled. Alleles and genotypes at five positions [rs6269 (A>G), rs4633 (C>T), rs4818 (C>G), rs4680 (C>G) and rs165599 (A>G)] in the COMT gene were genotyped from peripheral blood DNA.

RESULTS

Alleles and genotypes of the rs4818 COMT gene polymorphism were significantly associated with increased susceptibility to FM. The rs4818 GG genotype was more strongly associated with FM compared to the CC genotype (OR = 1.680, 95% CI: 1.057, 2.672, p = 0.027). Although allele and genotype frequencies did not differ among groups, the rs4633 CT genotype was not associated with the presence of FM following adjustment for age and sex (OR = 0.745; 95% CI: 0.558, 0.995; p = 0.046). However, no association was observed between clinical measures and individual COMT SNPs. In haplotype analysis, there was a significant association between ACG haplotype and FM susceptibility sex (OR = 2.960, 95% CI: 1.447, 6.056, p = 0.003) and the number of tender points (p = 0.046).

CONCLUSIONS

This large-scale study suggests that polymorphisms of the COMT gene may be associated with FM risk and pain sensitivity in Korean FM patients. However, our results differed to those of previous studies, suggesting ethnic variation in COMT gene polymorphisms in FM.

WHAT DOES THIS STUDY ADD

By contrast to Caucasian and Latin-American populations, the COMT gene polymorphisms are associated with FM risk and pain sensitivity in Korean FM patients, suggesting ethnic variation in COMT gene polymorphisms.