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Neto AC, Santos-Pereira M, Abreu-Mendes P, Neves D, Almeida H, Cruz F, Charrua A. The Unmet Needs for Studying Chronic Pelvic/Visceral Pain Using Animal Models. Biomedicines 2023; 11:biomedicines11030696. [PMID: 36979674 PMCID: PMC10045296 DOI: 10.3390/biomedicines11030696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 03/03/2023] Open
Abstract
The different definitions of chronic pelvic/visceral pain used by international societies have changed over the years. These differences have a great impact on the way researchers study chronic pelvic/visceral pain. Recently, the role of systemic changes, including the role of the central nervous system, in the perpetuation and chronification of pelvic/visceral pain has gained weight. Consequently, researchers are using animal models that resemble those systemic changes rather than using models that are organ- or tissue-specific. In this review, we discuss the advantages and disadvantages of using bladder-centric and systemic models, enumerating some of the central nervous system changes and pain-related behaviors occurring in each model. We also present some drawbacks when using animal models and pain-related behavior tests and raise questions about possible, yet to be demonstrated, investigator-related bias. We also suggest new approaches to study chronic pelvic/visceral pain by refining existing animal models or using new ones.
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Affiliation(s)
- Ana Catarina Neto
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
| | - Mariana Santos-Pereira
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
| | - Pedro Abreu-Mendes
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
- Department of Urology, Centro Hospitalar de São João, 4200-319 Porto, Portugal
- Physiology and Surgery Department, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
| | - Delminda Neves
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
| | - Henrique Almeida
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
- Ginecologia-Obstetrícia, Hospital-CUF Porto, 4100-180 Porto, Portugal
| | - Francisco Cruz
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
- Department of Urology, Centro Hospitalar de São João, 4200-319 Porto, Portugal
- Physiology and Surgery Department, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
| | - Ana Charrua
- Experimental Biology Unit, Department of Biomedicine, Faculty of Medicine of University of Porto, 4200-319 Porto, Portugal
- I3S—Instituto de Investigação e Inovação em Saúde, University of Porto, 4200-135 Porto, Portugal
- Correspondence:
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Huang J, Zhang Y, Zhang Q, Wei L, Zhang X, Jin C, Yang J, Li Z, Liang S. The current status and trend of the functional magnetic resonance combined with stimulation in animals. Front Neurosci 2022; 16:963175. [PMID: 36213733 PMCID: PMC9540855 DOI: 10.3389/fnins.2022.963175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
As a non-radiative, non-invasive imaging technique, functional magnetic resonance imaging (fMRI) has excellent effects on studying the activation of blood oxygen levels and functional connectivity of the brain in human and animal models. Compared with resting-state fMRI, fMRI combined with stimulation could be used to assess the activation of specific brain regions and the connectivity of specific pathways and achieve better signal capture with a clear purpose and more significant results. Various fMRI methods and specific stimulation paradigms have been proposed to investigate brain activation in a specific state, such as electrical, mechanical, visual, olfactory, and direct brain stimulation. In this review, the studies on animal brain activation using fMRI combined with different stimulation methods were retrieved. The instruments, experimental parameters, anesthesia, and animal models in different stimulation conditions were summarized. The findings would provide a reference for studies on estimating specific brain activation using fMRI combined with stimulation.
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Unveil the pain of endometriosis: from the perspective of the nervous system. Expert Rev Mol Med 2022; 24:e36. [PMID: 36059111 DOI: 10.1017/erm.2022.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Endometriosis is a chronic inflammatory disease with pelvic pain and uncharacteristic accompanying symptoms. Endometriosis-associated pain often persists despite treatment of the disease, thus it brings a deleterious impact on their personal lives as well as imposing a substantial economic burden on them. At present, mechanisms underlie endometriosis-associated pain including inflammatory reaction, injury, aberrant blood vessels and the morphological and functional anomaly of the peripheral and central nervous systems. The nerve endings are influenced by the physical and chemical factors surrounding the lesion, via afferent nerve to the posterior root of the spinal nerve, then to the specific cerebral cortex involved in nociception. However, our understanding of the aetiology and mechanism of this complex pain process caused by endometriosis remains incomplete. Identifying the pathogenesis of endometriosis is crucial to disease management, offering proper treatment, and helping patients to seek novel targets for the maintenance and contributors of chronic pain. The main aim of this review is to focus on every possible mechanism of pain related to endometriosis in both peripheral and central nervous systems, and to present related mechanisms of action from the interaction between peripheral lesions and nerves to the changes in transmission of pain, resulting in hyperalgesia and the corresponding alterations in cerebral cortex and brain metabolism.
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Tajerian M, Amrami M, Betancourt JM. Is there hemispheric specialization in the chronic pain brain? Exp Neurol 2022; 355:114137. [PMID: 35671801 PMCID: PMC10723052 DOI: 10.1016/j.expneurol.2022.114137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 11/25/2022]
Abstract
Organismal bilateral symmetry is associated with near-identical halves of the central nervous system, with certain functions displaying specialization through one brain hemisphere. The processing of pain in the brain as well as brain plasticity in the context of painful injuries have garnered much attention in recent decades. Noninvasive brain imaging studies in pain-free human subjects have identified multiple brain regions that are linked to the sensory and affective components of pain. Longlasting adaptations in brains of chronic pain sufferers have likewise been described, suggesting a mechanism for pain chronification. Invasive molecular and biochemical studies in animal models have expanded on these findings, with added emphasis on the role of specific genes and molecules involved. To date, the extent of hemispheric asymmetry in the context of pain is not well-understood. This topical review evaluates the evidence of hemispheric specialization observed in humans and rodent models of pain and compares it to findings where such asymmetry is absent. Our review shows conflicting information regarding the existence of pain-related asymmetry, and if so, the side to which it can be localized. This could be due to the heterogeneity of pain processing pathways, heterogeneity in study parameters, as well as differences in data reporting. With the advent of progressively sophisticated non-invasive tools that can be used in human subjects, in addition to more precise methods to visualize and control specific brain regions or neuronal ensembles in animal models, we predict that the next few decades will witness a better understanding of the supraspinal control and processing of chronic pain, including the role of each of its hemispheres.
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Affiliation(s)
- Maral Tajerian
- Department of Biology, Queens College, City University of New York, Queens, NY 11367, USA; The Graduate Center, City University of New York, New York, NY 10016, USA.
| | - Michael Amrami
- Department of Biology, Queens College, City University of New York, Queens, NY 11367, USA
| | - John Michael Betancourt
- Neuroscience Graduate Program, Graduate School of Medical Sciences, Weill Cornell Medicine, New York, NY 10021, USA
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Phan VT, Stratton P, Tandon HK, Sinaii N, Aredo JV, Karp BI, Merideth MA, Shah JP. Widespread myofascial dysfunction and sensitisation in women with endometriosis-associated chronic pelvic pain: A cross-sectional study. Eur J Pain 2021; 25:831-840. [PMID: 33326662 DOI: 10.1002/ejp.1713] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 12/12/2020] [Indexed: 01/11/2023]
Abstract
BACKGROUND Chronic pelvic pain persists in some women with endometriosis even after lesion removal and optimized hormonal treatment. OBJECTIVE Characterize the presence and distribution of pain, myofascial dysfunction and sensitisation beyond the pelvis in women with endometriosis-associated chronic pelvic pain. METHODS Cross-sectional study of 30 women prior to participation in a clinical trial. Evaluation included pain-focused abdominopelvic gynaecologic examination with the identification of pelvic floor muscle spasm. Neuro-musculoskeletal examination assessed paraspinal allodynia and hyperalgesia bilaterally and myofascial trigger points in 13 paired muscles. Pressure-pain thresholds were measured over interspinous ligaments and trigger points. Women completed the body territories element of the Body Pain Index. RESULTS All women had a pelvic floor muscle spasm that they self-identified as a major focus of pain. Twenty of 30 women described their pelvic pain as focal. However, all demonstrated widespread myofascial dysfunction with low pressure-pain thresholds and trigger points in over two-thirds of 26 assessed regions. Widespread spinal segmental sensitisation was present in 17/30, thoracic in 21/30 and lumbosacral/pelvic in 18/30. Cervical sensitisation manifested as low pressure-pain thresholds with 23/30 also reporting recurrent, severe headaches and 21/30 experiencing orofacial pain. Those reporting diffuse pelvic pain were more likely to have widespread (p = .024) and lumbosacral/pelvic (p = .036) sensitisation and report over 10 painful body areas (p = .009). CONCLUSIONS Women with endometriosis-associated chronic pelvic pain often have myofascial dysfunction and sensitisation beyond the pelvic region that may be initiated or maintained by on-going pelvic floor spasm. These myofascial and nervous system manifestations warrant consideration when managing pain in this population. Clinicaltrials.gov identifier: NCT01553201. SIGNIFICANCE Women with endometriosis often have pelvic pain persisting after surgery despite hormonal therapies and these women have regional pelvic sensitisation and myofascial dysfunction. Pelvic floor muscle spasm is a major pain focus in this population. Sensitisation and myofascial dysfunction are widespread, beyond the pelvic region. On-going pelvic floor spasm may initiate or maintain sensitisation. Myofascial/sensitisation manifestations warrant consideration when managing pain in this population.
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Affiliation(s)
- Vy T Phan
- Rehabilitation Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Pamela Stratton
- Office of the Clinical Director, Intramural Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Hannah K Tandon
- Rehabilitation Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Ninet Sinaii
- Biostatistics & Clinical Epidemiology Service, Intramural Research Program, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | | | - Barbara I Karp
- Office of the Clinical Director, Intramural Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Melissa A Merideth
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jay P Shah
- Rehabilitation Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD, USA
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Correia-Caeiro C, Holmes K, Miyabe-Nishiwaki T. Extending the MaqFACS to measure facial movement in Japanese macaques (Macaca fuscata) reveals a wide repertoire potential. PLoS One 2021; 16:e0245117. [PMID: 33411716 PMCID: PMC7790396 DOI: 10.1371/journal.pone.0245117] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 12/23/2020] [Indexed: 02/01/2023] Open
Abstract
Facial expressions are complex and subtle signals, central for communication and emotion in social mammals. Traditionally, facial expressions have been classified as a whole, disregarding small but relevant differences in displays. Even with the same morphological configuration different information can be conveyed depending on the species. Due to a hardwired processing of faces in the human brain, humans are quick to attribute emotion, but have difficulty in registering facial movement units. The well-known human FACS (Facial Action Coding System) is the gold standard for objectively measuring facial expressions, and can be adapted through anatomical investigation and functional homologies for cross-species systematic comparisons. Here we aimed at developing a FACS for Japanese macaques, following established FACS methodology: first, we considered the species' muscular facial plan; second, we ascertained functional homologies with other primate species; and finally, we categorised each independent facial movement into Action Units (AUs). Due to similarities in the rhesus and Japanese macaques' facial musculature, the MaqFACS (previously developed for rhesus macaques) was used as a basis to extend the FACS tool to Japanese macaques, while highlighting the morphological and appearance changes differences between the two species. We documented 19 AUs, 15 Action Descriptors (ADs) and 3 Ear Action Units (EAUs) in Japanese macaques, with all movements of MaqFACS found in Japanese macaques. New movements were also observed, indicating a slightly larger repertoire than in rhesus or Barbary macaques. Our work reported here of the MaqFACS extension for Japanese macaques, when used together with the MaqFACS, comprises a valuable objective tool for the systematic and standardised analysis of facial expressions in Japanese macaques. The MaqFACS extension for Japanese macaques will now allow the investigation of the evolution of communication and emotion in primates, as well as contribute to improving the welfare of individuals, particularly in captivity and laboratory settings.
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Affiliation(s)
| | - Kathryn Holmes
- School of Psychology, University of Lincoln, Lincoln, Lincolnshire, United Kingdom
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Zheng P, Jia S, Guo D, Chen S, Zhang W, Cheng A, Xie W, Sun G, Leng J, Lang J. Central Sensitization-Related Changes in Brain Function Activity in a Rat Endometriosis-Associated Pain Model. J Pain Res 2020; 13:95-107. [PMID: 32021399 PMCID: PMC6968808 DOI: 10.2147/jpr.s232313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/17/2019] [Indexed: 12/31/2022] Open
Abstract
Background Pain sensitization processing in the central nervous system may be related to endometriosis-associated pain in patients. The purpose of this study was to understand the alterations in the abnormal pain response in central brain areas and explore the central sensitization mechanism of endometriosis-associated pain. Methods An endometriosis model was established in 40 Sprague-Dawley rats, and the rats underwent pain model assessment through behavioral tests. Twenty Sprague-Dawley rats underwent a sham operation as the control group. Thirteen pain rats and 8 control rats received Rs-fMRI examination to explore the brain functional activity areas, and the regional homogeneity (ReHo) method was used to analyze relevant functional signals among the whole brain. The states of neurons and expression of TRPV1 and NMDRA located in the abnormal ReHo signal brain regions were observed using Nissl staining, qRT-PCR and immunohistochemistry. Results The rats were divided into a pain group and a control group based on the different syndromes and behavioral assessments. We detected significant enhancement of ReHo signals in the anterior cingulate cortex, hippocampus, and thalamus and a reduction in the ReHo values in the basomedial amygdaloid nucleus (BM) and primary motor cortex (M1) in the pain rat group via Rs-fMRI examination. The number of Nissl bodies and apoptotic neurons was increased; moreover, the volume of neurons increased compensatorily in the cingulate cortex, thalamus and hippocampus in the pain group. TRPV1 and NMDRA were overexpressed in apoptotic neurons in the higher ReHo value brain regions in the endometriosis pain group. Conclusion These findings suggest that in rats with endometriosis-associated pain, ReHo signal enhancement was observed in the cingulate cortex, thalamus and hippocampus, which may be due to the increase in the number of apoptotic neurons or the compensatory increase in the volume of overactive neurons.
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Affiliation(s)
- Ping Zheng
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
| | - Shuangzheng Jia
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
| | - Dalong Guo
- Air Force Medical Center, PLA, Beijing, People's Republic of China
| | - Sikai Chen
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
| | - Wen Zhang
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
| | - Aoshuang Cheng
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
| | - Weijie Xie
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100193, People's Republic of China
| | - Guibo Sun
- Institute of Medicinal Plant Development, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100193, People's Republic of China
| | - Jinhua Leng
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
| | - Jinghe Lang
- Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, People's Republic of China
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Sieberg CB, Lunde CE, Borsook D. Endometriosis and pain in the adolescent- striking early to limit suffering: A narrative review. Neurosci Biobehav Rev 2019; 108:866-876. [PMID: 31862211 DOI: 10.1016/j.neubiorev.2019.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/03/2019] [Accepted: 12/03/2019] [Indexed: 12/17/2022]
Abstract
Endometriosis, a condition in which uterine tissue grows outside the uterus, is a debilitating disease, affecting millions of women and costing the United States approximately $78 billion annually in pain- related disability. It is also the leading cause of chronic pelvic pain (CPP), which is often unresponsive to existing treatments. Adolescent women with the disease are at particular risk as there are often significant diagnostic delays, which in turn can exacerbate pain. Research and treatment guidelines for adolescents with endometriosis are largely based on studies for adult women due to the limited number of studies focusing on adolescents. The current paper critically reviews the literature as it pertains to endometriosis pathophysiology, mechanisms contributing to CPP, and treatment implications and recommendations with a focus on gaps related to adolescents.
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Affiliation(s)
- Christine B Sieberg
- Center for Pain and the Brain (P.A.I.N. Group), Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital, USA; Biobehavioral Pediatric Pain Lab, Department of Psychiatry, Boston Children's Hospital, USA; Department of Psychiatry, Harvard Medical School, USA; Department of Anesthesiology, Harvard Medical School, USA.
| | - Claire E Lunde
- Center for Pain and the Brain (P.A.I.N. Group), Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital, USA; Biobehavioral Pediatric Pain Lab, Department of Psychiatry, Boston Children's Hospital, USA; Nuffield Department of Women's and Reproductive Health, Medical Sciences Division, University of Oxford, UK
| | - David Borsook
- Center for Pain and the Brain (P.A.I.N. Group), Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital, USA; Department of Anesthesiology, Harvard Medical School, USA
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