The journal of pain : official journal of the American Pain Society
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Observational Study
Enrichment of genomic pathways based on differential DNA methylation associated with chronic postsurgical pain and anxiety in children - a prospective, pilot study.
We have reported child anxiety sensitivity (Child Anxiety Sensitivity Index [CASI]) predicts chronic postsurgical pain (CPSP). Herein, we evaluated DNA methylation profiles to understand the gene-environment interactions underlying CPSP and CASI, to identify shared, enriched, genomic pathways. In 73 prospectively recruited adolescents undergoing spine fusion, preoperative CASI and pain data over 12 months after surgery were collected. ⋯ This pilot study provides new epigenetic insights into the pathophysiology of CPSP and a basis for future studies in biomarker development and targetable interventions. PERSPECTIVE: Differential DNA methylation in regulatory genomic regions enriching shared neural pathways were associated with CPSP and CASI in adolescents undergoing spine surgery. Our findings support GABA hypofunction and the roles of the dopamine-DARPP32 pathway in emotion/reward contributing to behavioral maintenance of pain 10 to 12 months after surgery.
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Sensorimotor cortical activity is altered in both the immediate acute and chronic stages of musculoskeletal pain. However, these changes are opposite, with decreased cortical activity reported in experimentally induced acute pain (lasting minutes to hours), and increased cortical activity in chronic, clinical pain (lasting >6 months). It is unknown whether sensorimotor cortical activity is altered in acute, clinical musculoskeletal pain (lasting <4 weeks). ⋯ However, individual variation was high, suggesting individual adaptation of cortical plasticity in acute pain. PERSPECTIVE: This is the first study to examine sensorimotor cortical activity in the acute stage of clinical LBP. This information is critical for understanding the neurophysiology of acute LBP.
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Sensory neuron nicotinic acetylcholine receptors (nAChRs) contribute to pain associated with tissue injury. However, there are marked differences between rats and mice with respect to both the properties and distribution of nAChR currents in sensory neurons. Because both species are used to understand pain signaling in humans, we sought to determine whether the currents present in either species was reflective of those present in human sensory neurons. ⋯ These results suggest that there are not only species differences in the sensory neuron distribution of nAChR currents between rodent and human, but that the subunit composition of the channel underlying human nAChR currents may be different from those in the mouse or rat. PERSPECTIVE: The properties and distribution of nicotine evoked currents in human sensory neurons were markedly different from those previously observed in mice and rats. These observations add additional support to the suggestion that human sensory neurons may be an essential screening tool for those considering moving novel therapeutics targeting primary afferents into clinical trials.
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Parents play a critical role in children's experience of, and recovery from, chronic pain. Although several parental factors have been linked to child pain and functioning, these factors are typically examined in isolation or as moderators or mediators. Structural equation modeling affords the opportunity to examine the extent to which parental factors are interrelated, and if there are differential associations among parental factors and child outcomes. ⋯ Findings support the inclusion of parent chronic pain status and physical and psychological functioning as part of a comprehensive assessment of youth with chronic pain and may inform new parental intervention targets to improve child outcomes. PERSPECTIVE: A unified structural equation model indicated parents' own chronic pain characteristics and physical and psychological functioning represent important factors associated with child pain and functioning. Current family-based interventions that often primarily focus on parent responses to child pain may need to be adapted to more comprehensively address parental factors.
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The effectiveness of pain-reducing interventions in newborns can only be determined if pain measurement instruments are responsive; that is, able to detect a decrease in pain intensity after the pain-reducing intervention. This review assesses the methodologic quality of studies on this measurement property-the responsiveness. We searched the literature published until January 2018 for validation studies of pain measurement instruments focusing on responsiveness to pain-reducing treatment in neonates. ⋯ PERSPECTIVE: This review focuses on the property of measurement instruments to detect changes in pain intensity after a pain-reducing intervention in neonates. We concluded that this property-the responsiveness-is under studied and that the methodologic quality of the included studies was low. Future high-quality validation studies should focus on responsiveness.