Effect of OPRM1/COMT gene polymorphisms on sufentanil labor analgesia: a cohort study based on propensity score matching

Background: This study investigated the use of COMT G1947A and OPRM1 A118G polymorphisms as predictive markers for sufentanil epidural analgesia. Methods: The visual analogue scale (VAS) score, and sufentanil consumption of 136 pairs of parturients using sufentanil with lidocaine and ropivacaine for epidural analgesia were used for analysis. Results: OPRM1 AG/GG had lower VAS score difference between fifth and 0 min (1.55 vs 1.87; p = 0.012) and higher consumption (19.65 μg vs 17.11 μg; p = 0.049) than AA carriers. COMT GA/AA had higher VAS score difference than GG carriers (1.86 vs 1.55; p = 0.021). Conclusion: Sufentanil may provide better epidural labor analgesia in OPRM1 AA and COMT GA/AA carriers compared with OPRM1 AG/GG and COMT GG carriers. Clinical Trial Registration: ChiCTR1900026897 (Chinese Clinical Trial Center Registry).

Effect of ADRA2A gene polymorphisms on the anesthetic and analgesic effects of dexmedetomidine in Chinese Han women with cesarean section

It is well known that differences in drug reactions among individuals are widespread, and therefore the study of genetic polymorphisms of drug targets has become a research hotspot. Dexmedetomidine is clinically effective by acting on α2 adrenergic receptor and the impact of the adrenoceptor α2A gene (ADRA2A) polymorphisms on the anesthetic and analgesic effects of dexmedetomidine is related to the clinical application of dexmedetomidine. The present study aimed to analyze the effects of the rs1800035, rs201376588 and rs775887911 locus single-nucleotide polymorphisms of the ADRA2A on the anesthetic and analgesic effects of dexmedetomidine in Chinese Han women. A total of 434 Chinese women undergoing cesarean section were enrolled in this study. A 3-ml fasting venous blood sample was collected from all subjects for genomic DNA extraction and genotype detection. The pre-anesthetic and post-anesthetic pain threshold (PTh), pain tolerance threshold (PTTh), mean arterial pressure, heart rate, blood oxygen saturation, cortisol (Cor) content, blood glucose (Glu) content, opioid usage, patient-controlled analgesia pressing times, surgical satisfaction and postoperative adverse reactions were recorded. The visual analogue scale (VAS) and Ramsay sedation score were evaluated. PTh and PTTh in the wild-type women were higher than those in the women with mutations (P<0.05). The postoperative VAS scores of wild-type women were lower than those of mutants (P<0.05). The Ramsay sedation scores of wild-type patients at 12 h after the operation were significantly higher than in those with mutations (P<0.05). The levels of Cor and Glu in women with mutations were significantly higher than those of wild-type women at 12, 24 and 48 h after surgery (P<0.05). The satisfaction with surgery of wild-type patients was higher than that of patients with mutations (P<0.05). Gene mutations of rs1800035, rs201376588 and rs775887911 loci in the ADRA2A gene reduced the anesthetic and analgesic effect during and after cesarean section in Chinese Han women. Postoperative analgesia of mothers with mutations may require higher doses of analgesics.

Labour analgesia; Molecular pathway and the role of nanocarriers: a systematic review

Labour is considered to be one of the most painful procedures in human experience. The most effective technique for pain relief during labour is neuraxial labour analgesia which provides analgesia without maternal or fetal sedation. Genetic predisposition may be of importance for pain perception and women experience varying degrees of pain in labour. Genetic variations in opioid receptor (OPR) genes may influence the response to epidural opioid analgesia during labour. The single-nucleotide polymorphism, A118G of the mu opioid receptor gene (oprm1), has been associated with altered pain perception. Targeted drug delivery reduces toxic side effects. Liposomes, nano-particles, nanofibres hydrogel, have been suggested to deliver anaesthetic drugs.

Pharmacogenetics in obstetric anesthesia

The 21st century has been billed as the era of "precision/personalized medicine." Genetic investigation of clinical syndromes may guide therapy as well as reveal previously unknown biological or pharmacological pathways that may result in novel drug therapies. Several clinical issues in obstetrics and obstetric anesthesiology have been targets for genetic investigations. These include evaluation of the genetic effects on preterm labor and the progression of labor, spinal anesthesia-induced hypotension and the response to medications used to treat hypotension, and the effect of gene variants on pain and analgesic responses. Most studies have examined specific single nucleotide polymorphisms. Findings have revealed modest effects of genetic variation without tangible impact on current clinical practice. Over the next decade, increased availability of whole exome and genome sequencing, epigenetics, large genetic databases, computational biology and other information technology, and more rapid methods of real-time genotyping may increase the impact of genetics in the clinical arena of obstetrics and obstetric anesthesia.

Literature-Informed Analysis of a Genome-Wide Association Study of Gestational Age in Norwegian Women and Children Suggests Involvement of Inflammatory Pathways

Background

Five-to-eighteen percent of pregnancies worldwide end in preterm birth, which is the major cause of neonatal death and morbidity. Approximately 30% of the variation in gestational age at birth can be attributed to genetic factors. Genome-wide association studies (GWAS) have not shown robust evidence of association with genomic loci yet.

Methods

We separately investigated 1921 Norwegian mothers and 1199 children from pregnancies with spontaneous onset of delivery. Individuals were further divided based on the onset of delivery: initiated by labor or prelabor rupture of membranes. Genetic association with ultrasound-dated gestational age was evaluated using three genetic models and adaptive permutations. The top-ranked loci were tested for enrichment in 12 candidate gene-sets generated by text-mining PubMed abstracts containing pregnancy-related keywords.

Results

The six GWAS did not reveal significant associations, with the most extreme empirical p = 5.1 × 10⁻⁷. The top loci from maternal GWAS with deliveries initiated by labor showed significant enrichment in 10 PubMed gene-sets, e.g., p = 0.001 and 0.005 for keywords "uterus" and "preterm" respectively. Enrichment signals were mainly caused by infection/inflammation-related genes TLR4, NFKB1, ABCA1, MMP9. Literature-informed analysis of top loci revealed further immunity genes: IL1A, IL1B, CAMP, TREM1, TFRC, NFKBIA, MEFV, IRF8, WNT5A.

Conclusion

Our analyses support the role of inflammatory pathways in determining pregnancy duration and provide a list of 32 candidate genes for a follow-up work. We observed that the top regions from GWAS in mothers with labor-initiated deliveries significantly more often overlap with pregnancy-related genes than would be expected by chance, suggesting that increased sample size would benefit similar studies.

Depressed mood, anxiety, and the use of labor analgesia

Relatively little is known about mental health and labor pain. The aim of this study was to assess if self-rated antenatal depressed mood and anxiety are associated with pain-related behaviors and self-reported labor pain. We also wanted to replicate our previous finding of altered labor pain behavior in carriers of a specific guanosine triphosphate cyclohydrolase 1 gene (GCH1) haplotype. Ninety-nine women in gestational weeks 37 to 40 filled out questionnaires on depression and anxiety symptoms and later rated their labor pain by use of visual analog scales. Each subject was also genotyped for GCH1. Following adjustment for relevant confounders, women who arrived early to the delivery unit (cervical dilation <5 cm) had a significantly higher antenatal Montgomery-Åsberg Depression Rating Scale (MADRS-S) score, p < 0.05, than late arrivers (cervical dilation >5 cm). Women with increased Spielberger State-Trait Anxiety Inventory (STAI-T) scores reported higher self-rated pain prior to labor analgesia, p < 0.05, than women with low STAI-T scores. No association between the GCH1 pain-protective haplotype and cervical dilation was found, but a previously demonstrated association with increased use of second-line analgesia was confirmed. Depressed mood during pregnancy is associated with early arrival to the delivery department, whereas antenatal anxiety is associated with increased self-rated pain prior to labor analgesia.

Pharmacogenetics of OPRM1

Pharmacogenetic research has the potential to explain the variation in treatment efficacy within patient populations. Understanding the interaction between genetic variation and medications may provide a method for matching patients to the most effective therapeutic options and improving overall patient outcomes. The OPRM1 gene has been a target of interest in a large number of pharmacogenetic studies due to its genetic and structural variation, as well as the role of opioid receptors in a variety of disorders. The mu-opioid receptor (MOR), encoded by OPRM1, naturally regulates the analgesic response to pain and also controls the rewarding effects of many drugs of abuse, including opioids, nicotine, and alcohol. Genetic variants in OPRM1, particularly the non-synonymous polymorphism A118G, have been repeatedly associated with the efficacy of treatments for pain and various types of dependence. This review focuses on the current understanding of the pharmacogenetic impact of OPRM1, primarily with regard to the treatment of pain and addiction.

Genetic contributions to labor pain and progress

Studies on genetic contributions to labor analgesia have essentially evaluated the μ-opioid receptor gene (OPRM1), with some evidence that p.118A/G of OPRM1 influences the response to neuraxial opioids. As for labor progress, the β2-adrenergic receptor gene (ADRB2) is associated with preterm labor and delivery, and impacts the course of labor. Taken together though, there is no evidence that pharmacogenetic testing is needed or beneficial in the context of obstetric anesthesia; however, realizing the influence of genetic variants on specific phenotypes provides the rationale for a more cautious interpretation of clinical studies that attempt to find a dose-regimen that fits all.

Effects of OPRM1 A118G polymorphism on epidural analgesia with fentanyl during labor: a meta-analysis

BACKGROUND

Emerging evidence has shown that the most common polymorphism (A118G; rs1799971 A>G) in the μ-opioid receptor (OPRM1) gene may influence the response to labor analgesia, but individually published studies showed inconclusive results.

OBJECTIVE

This meta-analysis aimed to derive a more precise estimation of the effects of the OPRM1 A118G polymorphism on epidural analgesia with fentanyl during labor.

METHODS

A literature search was conducted on PubMed, Embase, Web of Science, and China BioMedicine databases before April 1st, 2013. The crude standardized mean difference (SMD) or odds ratio (OR) with 95% confidence interval (CI) was calculated.

RESULTS

Six clinical studies were included with a total 838 women who received epidural analgesia with fentanyl during labor. The meta-analysis results indicated that women carrying the G allele (AG+GG) of the OPRM1 A118G polymorphism required less fentanyl doses to achieve adequate pain relief compared with those with the AA homozygote (SMD=-0.24, 95% CI [-0.44, -0.03], p=0.022). The 118G variant was associated with a decreased ED50 of fentanyl for labor analgesia (SMD=-1.56, 95% CI [-1.97, -1.15], p<0.001). The analgesia satisfaction in women carrying the G allele (AG+GG) was higher than those with the AA homozygote (SMD=0.22, 95% CI [0.05, 0.39], p=0.012). However, there were no statistically significant differences between an AA homozygote and a G carrier (AG+GG) in the incidence of nausea and vomiting (OR=1.99, 95% CI [0.88, 4.52], p=0.101).

CONCLUSION

In conclusion, the current meta-analysis indicates that women carrying the G allele (AG+GG) of OPRM1 A118G polymorphism may have a good response to epidural analgesia with fentanyl during labor. The OPRM1 A118G polymorphism may help predict individuals' response to epidural labor analgesia and so optimize postoperative pain control.