μ-Opioid Receptor Gene A118G Polymorphism Predicts Pain Recovery After Sexual Assault

Medications at the Emergency Department After Recent Rape

Rape is associated with myriad negative physical and mental health effects, yet little is known about medical prescribing following rape-related emergency room visits. The goal of this study was to examine factors associated with medications prescribed the same day as a sexual assault medical forensic examination (SAMFE). A total of 939 medical records (93.9% female) of a medical university in the Southeastern United States between July 1, 2014, and May 15, 2019, were paired with Sexual Assault Nurse Exam records. Demographic and assault characteristics were examined as correlates of medications prescribed at the emergency department within the same day of a SAMFE. All individuals were offered medications within the national guidelines. Intimate partner violence (IPV) was negatively associated with antibiotic prescriptions and with emergency contraception prescriptions. Genital injury and male gender of victim were positively associated with antiviral prescriptions. Non-genital injury was positively associated with both over-the-counter and prescription pain medication prescriptions. Report of strangulation was positively associated with accepting over-the-counter but not prescription pain medication. IPV and strangulation were positively associated with psychotropic prescriptions. Although specific medications were offered to individuals during the SAMFE, demographic and assault characteristics were associated with medication acceptability.

Pain is common after sexual assault and posttraumatic arousal/reactivity symptoms mediate the development of new or worsening persistent pain

ABSTRACT

Clinically significant new or worsening pain (CSNWP) is a common, yet often overlooked, sequelae of sexual assault. Little is known regarding factors influencing the development of CSNWP in sexual assault survivors. The current study used data from a recently completed prospective study to evaluate whether posttraumatic alterations in arousal and reactivity in the early aftermath of sexual assault influence the transition from acute to clinically significant new or worsening persistent pain. Women ≥ 18 years of age (n = 706) presenting for emergency care after sexual assault to 13 emergency care sites were enrolled in the study. Women completed assessments at the time of presentation as well as at 1 week (n = 706, 100%) and 6 weeks (n = 630, 91%). Nearly 70% of women reported CSNWP at the time of emergency care (n = 475, 69%), which persisted to 6 weeks in approximately 2 in 5 survivors (n = 248, 41%). A structural equation model adjusted for age, race, past trauma exposure, and preassault pain levels suggested that posttraumatic alterations in arousal/reactivity symptoms 1 week after assault partially mediated the transition from acute to persistent CSNWP. A significant portion (41%) of women sexual assault survivors develop CSNWP 6 weeks postassault. Posttraumatic arousal/reactivity symptoms in the early aftermath of assault contribute to CSNWP development; such symptoms are potential targets for secondary preventive interventions to reduce chronic postassault pain.

Somatic symptoms following sexual assault in adolescents: a prospective longitudinal study

Adults and young people with somatoform disorders and somatic symptoms retrospectively report high rates of sexual abuse. We aimed to assess somatic symptoms in young people in the aftermath of a sexual assault and to document links with assault characteristics, with psychopathology and with related functional impairment. This was a prospective cohort study of adolescents seen in specialized clinics in London in the first 6 weeks following a sexual assault and at 4-5 months follow-up. We enquired about somatic symptoms (headaches, abdominal pain and sickness) pre and post assault, and we assessed psychiatric disorders and functional impairment at follow-up using validated scales. Information was obtained on 94 females (mean age 15.6, SD 1.3). There was a statistically significant increase in the number of adolescents reporting somatic symptoms at 4-5-month follow-up (65/94, 69%) (p = 0.035), compared with estimated pre-assault rates (52/94, 55%) and a significant increase in somatic symptoms at follow-up among the victims of violent sexual abuse (p < .001). Subjects with somatic symptoms at follow-up had significant higher rates of psychiatric disorders - especially generalised anxiety disorder, panic disorder and major depressive disorders - as well as lower psychosocial functioning (p < 0.01), than those without somatic symptoms.

Polymorphisms of the μ-opioid receptor gene influence cerebral pain processing in fibromyalgia

Background

Dysregulation of the μ‐opioid receptor has been reported in fibromyalgia (FM) and was linked to pain severity. Here, we investigated the effect of the functional genetic polymorphism of the μ‐opioid receptor gene (OPRM1) (rs1799971) on symptom severity, pain sensitivity and cerebral pain processing in FM subjects and healthy controls (HC).

Methods

Symptom severity and pressure pain sensitivity was assessed in FM subjects (n = 70) and HC (n = 35). Cerebral pain‐related activation was assessed by functional magnetic resonance imaging during individually calibrated painful pressure stimuli.

Results

Fibromyalgia subjects were more pain sensitive but no significant differences in pain sensitivity or pain ratings were observed between OPRM1 genotypes. A significant difference was found in cerebral pain processing, with carriers of at least one G‐allele showing increased activation in posterior cingulate cortex (PCC) extending to precentral gyrus, compared to AA homozygotes. This effect was significant in FM subjects but not in healthy participants, however, between‐group comparisons did not yield significant results. Seed‐based functional connectivity analysis was performed with the seed based on differences in PCC/precentral gyrus activation between OPRM1 genotypes during evoked pain across groups. G‐allele carriers displayed decreased functional connectivity between PCC/precentral gyrus and prefrontal cortex.

Conclusions

G‐allele carriers showed increased activation in PCC/precentral gyrus but decreased functional connectivity with the frontal control network during pressure stimulation, suggesting different pain modulatory processes between OPRM1 genotypes involving altered fronto‐parietal network involvement. Furthermore, our results suggest that the overall effects of the OPRM1 G‐allele may be driven by FM subjects.

Significance

We show that the functional polymorphism of the μ‐opioid receptor gene OPRM1 was associated with alterations in the fronto‐parietal network as well as with increased activation of posterior cingulum during evoked pain in FM. Thus, the OPRM1 polymorphism affects cerebral processing in brain regions implicated in salience, attention, and the default mode network. This finding is discussed in the light of pain and the opioid system, providing further evidence for a functional role of OPRM1 in cerebral pain processing.

Protocol for the first large-scale emergency care-based longitudinal cohort study of recovery after sexual assault: the Women's Health Study

INTRODUCTION

Worldwide, an estimated 10%-27% of women are sexually assaulted during their lifetime. Despite the enormity of sexual assault as a public health problem, to our knowledge, no large-scale prospective studies of experiences and recovery over time among women presenting for emergency care after sexual assault have been performed.

METHODS AND ANALYSIS

Women ≥18 years of age who present for emergency care within 72 hours of sexual assault to a network of treatment centres across the USA are approached for study participation. Blood DNA and RNA samples and brief questionnaire and medical record data are obtained from women providing initial consent. Full consent is obtained at initial 1 week follow-up to analyse blood sample data and to perform assessments at 1 week, 6 weeks, 6 months and 1 year. These assessments include evaluation of survivor life history, current health and recovery and experiences with treatment providers, law enforcement and the legal system.

ETHICS AND DISSEMINATION

This study is approved by the University of North Carolina at Chapel Hill's Institutional Review Board (IRB) and the IRB of each participating study site. We hope to present the results of this study to the scientific community at conferences and in peer-reviewed journals.

The comorbidities of dysmenorrhea: a clinical survey comparing symptom profile in women with and without endometriosis

Purpose

Dysmenorrhea is a common disorder that substantially disrupts the lives of young women. The frequency of 14 associated symptoms both within and outside the pelvis was determined.

Patients and methods

Symptom questionnaires were completed by 168 women with dysmenorrhea, allocated to three groups based on their diagnostic status for endometriosis confirmed (Endo+), endometriosis excluded (Endo-), or endometriosis diagnosis unknown (No Lap). Those with endometriosis confirmed were further divided into current users (Endo+ Hx+) and non-users of hormonal treatments (Endo+ Hx-). Users of hormonal treatments were further divided into users (Endo+ Hx+ LIUCD+) and non-users (Endo+ Hx+ LIUCD-) of a levonorgestrel-releasing intra-uterine contraceptive device (LIUCD). The frequency and number of symptoms within groups and the effect of previous distressing sexual events were sought.

Results

Women with and without endometriosis lesions had similar symptom profiles, with a mean of 8.5 symptoms per woman. Only 0.6% of women reported dysmenorrhea alone. The presence of stabbing pelvic pains was associated with more severe dysmenorrhea (P=0.006), more days per month of dysmenorrhea (P=0.003), more days per month of pelvic pain (P=0.016), and a diagnosis of migraine (P=0.054). The symptom profiles of the Endo+ Hx+ and Endo+ Hx- groups were similar. A history of distressing sexual events was associated with an increased number of pain symptoms (P=0.003).

Conclusion

Additional symptoms are common in women with dysmenorrhea, and do not correlate with the presence or absence of endometriosis lesions. Our study supports the role of central sensitization in the pain of dysmenorrhea. The presence of stabbing pelvic pains was associated with increased severity of dysmenorrhea, days per month of dysmenorrhea, days per month of pelvic pain, and a diagnosis of migraine headache. A past history of distressing sexual events is associated with an increased number of pain symptoms.

Persistent pain after motor vehicle collision: comparative effectiveness of opioids vs nonsteroidal antiinflammatory drugs prescribed from the emergency department-a propensity matched analysis

Each year millions of Americans present to the emergency department (ED) for care after a motor vehicle collision (MVC); the majority (>90%) are discharged to home after evaluation. Acute musculoskeletal pain is the norm in this population, and such patients are typically discharged to home with prescriptions for oral opioid analgesics or nonsteroidal antiinflammatory drugs (NSAIDs). The influence of acute pain management on subsequent pain outcomes in this common ED population is unknown. We evaluated the effect of opioid analgesics vs NSAIDs initiated from the ED on the presence of moderate to severe musculoskeletal pain and ongoing opioid use at 6 weeks in a large cohort of adult ED patients presenting to the ED after MVC (n = 948). The effect of opioids vs NSAIDs was evaluated using an innovative quasi-experimental design method using propensity scores to account for covariate imbalances between the 2 treatment groups. No difference in risk for moderate to severe musculoskeletal pain at 6 weeks was observed between those discharged with opioid analgesics vs NSAIDs (risk difference = 7.2% [95% confidence interval: -5.2% to 19.5%]). However, at follow-up participants prescribed opioids were more likely than those prescribed NSAIDs to report use of prescription opioids medications at week 6 (risk difference = 17.5% [95% confidence interval: 5.8%-29.3%]). These results suggest that analgesic choice at ED discharge does not influence the development of persistent moderate to severe musculoskeletal pain 6 weeks after an MVC, but may result in continued use of prescription opioids. Supported by NIAMS R01AR056328 and AHRQ 5K12HS022998.

Genetic variant rs3750625 in the 3'UTR of ADRA2A affects stress-dependent acute pain severity after trauma and alters a microRNA-34a regulatory site

α2A adrenergic receptor (α2A-AR) activation has been shown in animal models to play an important role in regulating the balance of acute pain inhibition vs facilitation after both physical and psychological stress. To our knowledge, the influence of genetic variants in the gene encoding α2A-AR, ADRA2A, on acute pain outcomes in humans experiencing traumatic stress has not been assessed. In this study, we tested whether a genetic variant in the 3'UTR of ADRA2A, rs3750625, is associated with acute musculoskeletal pain (MSP) severity following motor vehicle collision (MVC, n = 948) and sexual assault (n = 84), and whether this influence was affected by stress severity. We evaluated rs3750625 because it is located in the seed binding region of miR-34a, a microRNA (miRNA) known to regulate pain and stress responses. In both cohorts, the minor allele at rs3750625 was associated with increased musculoskeletal pain in distressed individuals (stress*rs3750625 P = 0.043 for MVC cohort and P = 0.007 for sexual assault cohort). We further found that (1) miR-34a binds the 3'UTR of ADRA2A, (2) the amount of repression is greater when the minor (risk) allele is present, (3) miR-34a in the IMR-32 adrenergic neuroblastoma cell line affects ADRA2A expression, (4) miR-34a and ADRA2A are expressed in tissues known to play a role in pain and stress, (5) following forced swim stress exposure, rat peripheral nerve tissue expression changes are consistent with miR-34a regulation of ADRA2A. Together, these results suggest that ADRA2A rs3750625 contributes to poststress musculoskeletal pain severity by modulating miR-34a regulation.

Chronic widespread pain after motor vehicle collision typically occurs through immediate development and nonrecovery: results of an emergency department-based cohort study

Motor vehicle collision (MVC) can trigger chronic widespread pain (CWP) development in vulnerable individuals. Whether such CWP typically develops through the evolution of pain from regional to widespread or through the early development of widespread pain with nonrecovery is currently unknown. We evaluated the trajectory of CWP development (American College of Rheumatology criteria) among 948 European-American individuals who presented to the emergency department (ED) for care in the early aftermath of MVC. Pain extent was assessed in the ED and 6 weeks, 6 months, and 1 year after MVC on 100%, 91%, 89%, and 91% of participants, respectively. Individuals who reported prior CWP at the time of ED evaluation (n = 53) were excluded. Trajectory modeling identified a 2-group solution as optimal, with the Bayes Factor value (138) indicating strong model selection. Linear solution plots supported a nonrecovery model. Although the number of body regions with pain in the non-CWP group steadily declined, the number of body regions with pain in the CWP trajectory group (192/895, 22%) remained relatively constant over time. These data support the hypothesis that individuals who develop CWP after MVC develop widespread pain in the early aftermath of MVC, which does not remit.

Association of Epidemiologic Factors and Genetic Variants Influencing Hypothalamic-Pituitary-Adrenocortical Axis Function With Postconcussive Symptoms After Minor Motor Vehicle Collision

OBJECTIVES

To determine the influence of epidemiologic factors and the influence of genetic variants affecting FKBP5, a protein known to modulate hypothalamic-pituitary-adrenocortical axis function, on the severity of somatic symptoms commonly termed "postconcussive" 6 and 12 months after motor vehicle collision (MVC).

METHODS

European Americans 18 to 65 years of age who presented to one of eight emergency departments (EDs) after MVC were enrolled. Exclusion criteria included hospital admission. Blood samples were collected in the ED for genotyping. Participants completed evaluations including an adapted Rivermead Post-Concussive Symptoms Questionnaire in the ED and at 6 weeks, 6 months, and 1 year. Repeated-measures analysis of covariance was used to evaluate the association between epidemiologic factors (sociodemographic, pre-MVC health, collision characteristics, head injury, peritraumatic pain, and stress), FKBP5 genetic variants, and postconcussive symptom severity.

RESULTS

Among 943 patients recruited in the ED, follow-up was completed on 835 (88%) at 6 months and 857 (90%) at 1 year. Self-reported head impact during collision was not associated with chronic postconcussive symptom severity. After correction for multiple testing, three FKBP5 single-nucleotide polymorphisms (rs3800373, rs7753746, and rs9380526) predicted chronic postconcussive symptom severity, with an average symptom severity of 1.10 (95% confidence interval = 0.96-1.24), 1.36 (1.21-1.51), and 1.55 (1.23-1.88) for one, two, or three copies of minor allele at rs3800373 (p = .001). Similar effect sizes were observed for the minor alleles of rs7753746 and rs9380526.

CONCLUSIONS

Postconcussive symptoms after minor MVC are not generally related to the severity of mild brain injury. This study shows that neurobiologic stress systems may play a role in the pathogenesis of postconcussive symptoms.

Morphine-induced antinociception and reward in "humanized" mice expressing the mu opioid receptor A118G polymorphism

The rewarding and antinociceptive effects of opioids are mediated through the mu-opioid receptor. The A118G single nucleotide polymorphism in this receptor has been implicated in drug addiction and differences in pain response. Clinical and preclinical studies have found that the G allele is associated with increased heroin reward and self-administration, elevated post-operative pain, and reduced analgesic responsiveness to opioids. Male and female mice homozygous for the "humanized" 118AA or 118GG alleles were evaluated to test the hypothesis that 118GG mice are less sensitive to the rewarding and antinociceptive effects of morphine. We found that 118AA and 118GG mice of both genders developed conditioned place preference for morphine. All mice developed tolerance to the antinociceptive and hypothermic effects of morphine. However, morphine tolerance was not different between AA and GG mice. We also examined sensitivity to the antinociceptive and hypothermic effects of cumulative morphine doses. We found that 118GG mice show reduced hypothermic and antinociceptive responses on the hotplate for 10mg/kg morphine. Finally, we examined basal pain response and morphine-induced antinociception in the formalin test for inflammatory pain. We found no gender or genotype differences in either basal pain response or morphine-induced antinociception in the formalin test. Our data suggests that homozygous expression of the GG allele in mice blunts morphine-induced hypothermia and hotplate antinociception but does not alter morphine CPP, morphine tolerance, or basal inflammatory pain response.

Prior stress exposure increases pain behaviors in a rat model of full thickness thermal injury

Thermal burns among individuals working in highly stressful environments, such as firefighters and military Service Members, are common. Evidence suggests that pre-injury stress may exaggerate pain following thermal injury; however current animal models of burn have not evaluated the potential influence of pre-burn stress. This sham-controlled study evaluated the influence of prior stress exposure on post-burn thermal and mechanical sensitivity in male Sprague-Dawley rats. Rats were exposed to 20 min of inescapable swim stress or sham stress once per day for three days. Exposure to inescapable swim stress (1) increased the intensity and duration of thermal hyperalgesia after subsequent burn and (2) accelerated the onset of thermal hyperalgesia and mechanical allodynia after subsequent burn. This stress-induced exacerbation of pain sensitivity was reversed by pretreatment and concurrent treatment with the serotonin-norepinephrine reuptake inhibitor (SNRI) duloxetine. These data suggest a better understanding of mechanisms by which prior stress augments pain after thermal burn may lead to improved pain treatments for burn survivors.

μ-Opioid Receptor Gene A118 G Variants and Persistent Pain Symptoms Among Men and Women Experiencing Motor Vehicle Collision

The μ-opioid receptor 1 (OPRM1) binds endogenous opioids. Increasing evidence suggests that endogenous OPRM1 agonists released at the time of trauma may contribute to the development of posttraumatic musculoskeletal pain (MSP). In this prospective observational study, we evaluated the hypothesis that individuals with an AG or GG genotype at the OPRM1 A118 G allele, which results in a reduced response to opioids, would have less severe MSP 6 weeks after motor vehicle collision (MVC). Based on previous evidence, we hypothesized that this effect would be sex-dependent and most pronounced among women with substantial peritraumatic distress. European American men and women ≥ 18 years of age presenting to the emergency department after MVC and discharged to home after evaluation (N = 948) were enrolled. Assessments included genotyping and 6-week evaluation of overall MSP severity (0-10 numeric rating scale). In linear regression modeling, a significant A118 G Allele × Sex interaction was observed: an AG/GG genotype predicted reduced MSP severity among women with substantial peritraumatic distress (β = -.925, P = .014) but not among all women. In contrast, men with an AG/GG genotype experienced increased MSP severity at 6 weeks (β = .827, P = .019). Further studies are needed to understand the biologic mechanisms mediating observed sex differences in A118 G effects.

PERSPECTIVE

These results suggest a sex-dependent mechanism by which an emotional response to trauma (distress) contributes to a biologic mechanism (endogenous opioid release) that increases MSP in the weeks after stress exposure. These results also support the hypothesis that endogenous opioids influence pain outcomes differently in men and women.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 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; alcohol and drugs of abuse; 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.

No man is an island: living in a disadvantaged neighborhood influences chronic pain development after motor vehicle collision

Living in a lower socioeconomic status neighborhood has been shown to alter stress system function and is associated with a number of adverse health outcomes, but its influence on musculoskeletal pain (MSP) outcomes after traumatic stress exposures such as motor vehicle collision (MVC) has not been assessed. We performed a multicenter, prospective study that enrolled 948 European-American individuals within 24 hours of MVC who were discharged home after emergency department evaluation. Follow-up evaluations were completed via telephone or Internet survey 6 weeks, 6 months, and 1 year after MVC on 91%, 89%, and 91% of participants, respectively. A robust aggregate measure of census tract neighborhood disadvantage was derived, and individual-level characteristics assessed included socioeconomic and demographic characteristics, pain prior to MVC, litigation status, and opioid use. MSP was assessed in the emergency department; MSP and pain interference with daily activity were assessed at 6 weeks, 6 months, and 1 year. After adjustment for individual-level factors, living in more disadvantaged neighborhoods was associated with increased MSP (P=0.0009) and increased pain interference with daily function (P<0.0001). The relationship between neighborhood disadvantage and MSP was moderated by a common single nucleotide polymorphism, rs2817038, 5' of the gene encoding FKBP5, a functional regulator of glucocorticoid receptor sensitivity (interaction P-value=0.0015). These data support the hypothesis that low neighborhood socioeconomic status increases the likelihood of worse MSP outcomes after traumatic stress exposures such as MVC, and that this influence is mediated in part via its influence on stress system function.

Consequences of the 118A>G polymorphism in the OPRM1 gene: translation from bench to bedside?

The 118A>G single nucleotide polymorphism (SNP) in the μ-opioid receptor (OPRM1) gene has been the most described variant in pharmacogenetic studies regarding opioid drugs. Despite evidence for an altered biological function encoded by this variant, this knowledge is not yet utilized clinically. The aim of the present review was to collect and discuss the available information on the 118A>G SNP in the OPRM1 gene, at the molecular level and in its clinical manifestations. In vitro biochemical and molecular assays have shown that the variant receptor has higher binding affinity for β-endorphins, that it has altered signal transduction cascade, and that it has a lower expression compared with wild-type OPRM1. Studies using animal models for 118A>G have revealed a double effect of the variant receptor, with an apparent gain of function with respect to the response to endogenous opioids but a loss of function with exogenous administered opioid drugs. Although patients with this variant have shown a lower pain threshold and a higher drug consumption in order to achieve the analgesic effect, clinical experiences have demonstrated that patients carrying the variant allele are not affected by the increased opioid consumption in terms of side effects.

Polymorphisms in the glucocorticoid receptor co-chaperone FKBP5 predict persistent musculoskeletal pain after traumatic stress exposure

Individual vulnerability factors influencing the function of the hypothalamic-pituitary-adrenal axis may contribute to the risk of the development of persistent musculoskeletal pain after traumatic stress exposure. The objective of the study was to evaluate the association between polymorphisms in the gene encoding FK506 binding protein 51, FKBP5, a glucocorticoid receptor co-chaperone, and musculoskeletal pain severity 6 weeks after 2 common trauma exposures. The study included data from 2 prospective emergency department-based cohorts: a discovery cohort (n=949) of European Americans experiencing motor vehicle collision and a replication cohort of adult European American women experiencing sexual assault (n=53). DNA was collected from trauma survivors at the time of initial assessment. Overall pain and neck pain 6 weeks after trauma exposure were assessed using a 0-10 numeric rating scale. After adjustment for multiple comparisons, 6 FKBP5 polymorphisms showed significant association (minimum P<0.0001) with both overall and neck pain in the discovery cohort. The association of rs3800373, rs9380526, rs9394314, rs2817032, and rs2817040 with neck pain and/or overall pain 6 weeks after trauma was replicated in the sexual assault cohort, showing the same direction of the effect in each case. The results of this study indicate that genetic variants in FKBP5 influence the severity of musculoskeletal pain symptoms experienced during the weeks after motor vehicle collision and sexual assault. These results suggest that glucocorticoid pathways influence the development of persistent posttraumatic pain, and that such pathways may be a target of pharmacologic interventions aimed at improving recovery after trauma.