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Endometriosis is a chronic, hormone-dependent, inflammatory disease, characterized by the presence and growth of endometrial tissue outside the uterine cavity. It is associated with moderate to severe pelvic and abdominal pain symptoms, subfertility and a marked reduction in health-related quality of life. Furthermore, relevant co-morbidities with affective disorders like depression or anxiety have been described. These conditions have a worsening effect on pain perception in patients and might explain the negative impact on quality of life observed in those suffering from endometriosis-associated pain. Whereas several studies using rodent models of endometriosis focused on biological and histopathological similarities with the human situation, the behavioral characterization of these models was never performed. This study investigated the anxiety-related behaviors in a syngeneic model of endometriosis. Using elevated plus maze and the novel environment induced feeding suppression assays we observed the presence of anxiety-related behaviors in endometriosis-induced mice. In contrast, locomotion or generalized pain did not differ between groups. These results indicate that the presence of endometriosis lesions in the abdominal cavity could, similarly to patients, induce profound psychopathological changes/impairments in mice. These readouts might provide additional tools for preclinical identification of mechanisms relevant for development of endometriosis-related symptoms.

Secure platforms for bio-computation are critical to foster increasingly complex and data-intensive collaborations involving biomedical data. Here, we present Minuteman – an open-source cloud computing platform that can be securely used across organizations. Minuteman can be used for hosting data sources and running computational pipelines in an organized way. The platform consists of three fundamental features, 1) data operations including collaborative data processing and analytics, 2) customizable user access management for secure dissemination of the data, and 3) interactive exploration of the data through 3rdparty (e.g. shiny, dashboard etc.) applications that can be scaled using docker containers. Strict data access rules and user-specific roles are applied across the whole platform to maintain data security. Minuteman is ideal for scenarios where data security, and privileged access are critical, such as industry-academia collaborations, and multi-institution consortiums. Using single-cell transcriptomics preprocessing, analyses and visualization pipelines across labs, we showcase the utility of the Minuteman platform for biomedical data analyses. Minuteman code is available at (https://github.com/hayatlab/minuteman)

Supplemental Digital Content is Available in the Text., Endometriosis (ENDO) and interstitial cystitis/bladder pain syndrome (IC/BPS) are chronic pain conditions for which better treatments are urgently needed. Development of new therapies with proven clinical benefit has been slow. We have conducted a review of existing preclinical in vivo models for ENDO and IC/BPS in rodents, discussed to what extent they replicate the phenotype and pain experience of patients, as well as their relevance for translational research. In 1009 publications detailing ENDO models, 41% used autologous, 26% syngeneic, 18% xenograft, and 11% allogeneic tissue in transplantation models. Intraperitoneal injection of endometrial tissue was the subcategory with the highest construct validity score for translational research. From 1055 IC/BPS publications, most interventions were bladder centric (85%), followed by complex mechanisms (8%) and stress-induced models (7%). Within these categories, the most frequently used models were instillation of irritants (92%), autoimmune (43%), and water avoidance stress (39%), respectively. Notably, although pelvic pain is a hallmark of both conditions and a key endpoint for development of novel therapies, only a small proportion of the studies (models of ENDO: 0.5%-12% and models of IC/BPS: 20%-44%) examined endpoints associated with pain. Moreover, only 2% and 3% of publications using models of ENDO and IC/BPS investigated nonevoked pain endpoints. This analysis highlights the wide variety of models used, limiting reproducibility and translation of results. We recommend refining models so that they better reflect clinical reality, sharing protocols, and using standardized endpoints to improve reproducibility. We are addressing this in our project Innovative Medicines Initiative-PainCare/Translational Research in Pelvic Pain.

Single-cell sequencing improves our ability to understand biological systems at single-cell resolution and can be used to identify novel drug targets and optimal cell-types for target validation. However, tools that can interactively visualize and provide target-centric views of these large datasets are limited. We present SciViewer (Single-cell Interactive Viewer), a novel tool to interactively visualize, annotate and share single-cell datasets. SciViewer allows visualization of cluster, gene and pathway level information such as clustering annotation, differential expression, pathway enrichment, cell-type specificity, cellular composition, normalized gene expression and comparison across datasets. Further, we provide APIs for SciViewer to interact with publicly available pharmacogenomics databases for systematic evaluation of potential novel drug targets. We provide a module for non-programmatic upload of single-cell datasets. SciViewer will be a useful tool for data exploration and target discovery from single-cell datasets. It is available on GitHub (https://github.com/Dhawal-Jain/SciViewer).

ATP-dependent P2X3 receptors play a crucial role in the sensitization of nerve fibers and pathological pain pathways. They are also involved in pathways triggering cough and may contribute to the pathophysiology of endometriosis and overactive bladder. However, despite the strong therapeutic rationale for targeting P2X3 receptors, preliminary antagonists have been hampered by off-target effects, including severe taste disturbances associated with blocking the P2X2/3 receptor heterotrimer. Here we present a P2X3 receptor antagonist, eliapixant (BAY 1817080), which is both highly potent and selective for P2X3 over other P2X subtypes in vitro, including P2X2/3. We show that eliapixant reduces inflammatory pain in relevant animal models. We also provide the first in vivo experimental evidence that P2X3 antagonism reduces neurogenic inflammation, a phenomenon hypothesised to contribute to several diseases, including endometriosis. To test whether eliapixant could help treat endometriosis, we confirmed P2X3 expression on nerve fibers innervating human endometriotic lesions. We then demonstrate that eliapixant reduces vaginal hyperalgesia in an animal model of endometriosis-associated dyspareunia, even beyond treatment cessation. Our findings indicate that P2X3 antagonism could alleviate pain, including non-menstrual pelvic pain, and modify the underlying disease pathophysiology in women with endometriosis. Eliapixant is currently under clinical development for the treatment of disorders associated with hypersensitive nerve fibers.

Endometriosis is a common chronic inflammatory condition causing pelvic pain and infertility in women, with limited treatment options and 50% heritability. We leveraged genetic analyses in two species with spontaneous endometriosis, humans and the rhesus macaque, to uncover treatment targets. We sequenced DNA from 32 human families contributing to a genetic linkage signal on chromosome 7p13-15 and observed significant overrepresentation of predicted deleterious low-frequency coding variants in NPSR1, the gene encoding neuropeptide S receptor 1, in cases (predominantly stage III/IV) versus controls (P = 7.8 × 10-4). Significant linkage to the region orthologous to human 7p13-15 was replicated in a pedigree of 849 rhesus macaques (P = 0.0095). Targeted association analyses in 3194 surgically confirmed, unrelated cases and 7060 controls revealed that a common insertion/deletion variant, rs142885915, was significantly associated with stage III/IV endometriosis (P = 5.2 × 10-5; odds ratio, 1.23; 95% CI, 1.09 to 1.39). Immunohistochemistry, qRT-PCR, and flow cytometry experiments demonstrated that NPSR1 was expressed in glandular epithelium from eutopic and ectopic endometrium, and on monocytes in peritoneal fluid. The NPSR1 inhibitor SHA 68R blocked NPSR1-mediated signaling, proinflammatory TNF-α release, and monocyte chemotaxis in vitro (P < 0.01), and led to a significant reduction of inflammatory cell infiltrate and abdominal pain (P < 0.05) in a mouse model of peritoneal inflammation as well as in a mouse model of endometriosis. We conclude that the NPSR1/NPS system is a genetically validated, nonhormonal target for the treatment of endometriosis with likely increased relevance to stage III/IV disease.

Endometriosis (ENDO) and interstitial cystitis/bladder pain syndrome (IC/BPS) are chronic pain conditions for which better treatments are urgently needed. Development of new therapies with proven clinical benefit has been slow. We have conducted a review of existing preclinical in vivo models for ENDO and IC/BPS in rodents, discussed to what extent they replicate the phenotype and pain experience of patients, as well as their relevance for translational research. In 1009 publications detailing ENDO models, 41% used autologous, 26% syngeneic, 18% xenograft, and 11% allogeneic tissue in transplantation models. Intraperitoneal injection of endometrial tissue was the subcategory with the highest construct validity score for translational research. From 1055 IC/BPS publications, most interventions were bladder centric (85%), followed by complex mechanisms (8%) and stress-induced models (7%). Within these categories, the most frequently used models were instillation of irritants (92%), autoimmune (43%), and water avoidance stress (39%), respectively. Notably, although pelvic pain is a hallmark of both conditions and a key endpoint for development of novel therapies, only a small proportion of the studies (models of ENDO: 0.5%-12% and models of IC/BPS: 20%-44%) examined endpoints associated with pain. Moreover, only 2% and 3% of publications using models of ENDO and IC/BPS investigated nonevoked pain endpoints. This analysis highlights the wide variety of models used, limiting reproducibility and translation of results. We recommend refining models so that they better reflect clinical reality, sharing protocols, and using standardized endpoints to improve reproducibility. We are addressing this in our project Innovative Medicines Initiative-PainCare/Translational Research in Pelvic Pain.

The P2X4 receptor is a ligand-gated ion channel that is expressed on a variety of cell types, especially those involved in inflammatory and immune processes. High-throughput screening led to a new class of P2X4 inhibitors with substantial CYP 3A4 induction in human hepatocytes. A structure-guided optimization with respect to decreased pregnane X receptor (PXR) binding was started. It was found that the introduction of larger and more polar substituents on the ether linker led to less PXR binding while maintaining the P2X4 inhibitory potency. This translated into significantly reduced CYP 3A4 induction for compounds 71 and 73. Unfortunately, the in vivo pharmacokinetic (PK) profiles of these compounds were insufficient for the desired profile in humans. However, BAY-1797 (10) was identified and characterized as a potent and selective P2X4 antagonist. This compound is suitable for in vivo studies in rodents, and the anti-inflammatory and anti-nociceptive effects of BAY-1797 were demonstrated in a mouse complete Freund's adjuvant (CFA) inflammatory pain model.

Endometriosis is a common gynaecological disease of women in reproductive age, and is thought to arise from retrograde menstruation and implantation of endometrial tissue, mostly into the peritoneal cavity. The condition is characterized by a chronic, unresolved inflammatory process thereby contributing to pain as cardinal symptom in endometriosis. Elevated reactive oxygen species (ROS) and oxidative stress have been postulated as factors in endometriosis pathogenesis. We here set out for a systematic study to identify novel mechanisms and pathways relating to oxidative stress in ectopic peritoneal lesions. Using combined proteomic and transcriptomic approaches, we identified novel targets including upregulated pro-oxidative enzymes, such as amine oxidase 3/vascular adhesion protein 1 (AOC3/VAP1) as well as downregulated protective factors, in particular alkenal reductase PTGR1 and methionine sulfoxide reductase. Consistent with an altered ROS landscape, we observed hemoglobin / iron overload, ROS production and lipid peroxidation in ectopic lesions. ROS-derived 4-hydroxy-2-nonenal induced interleukin IL-8 release from monocytes. Notably, AOC3 inhibitors provoked analgesic effects in inflammatory pain models in vivo, suggesting potential translational applicability.

Chronic administration of medication can have an important impact on metabolic enzymes leading to physiological adaptations. Morphine metabolism in the liver has been extensively studied following acute morphine treatment but morphine metabolic processes in the central nervous system are poorly characterised. Long-term morphine treatment is limited by the development of tolerance, resulting in a decrease of its analgesic effect. Whether or not morphine analgesic tolerance affects in vivo brain morphine metabolism and blood-brain barrier (BBB) permeability remains a major pending question. Thus, our aim was to characterise the in vivo metabolism and BBB permeability of morphine after long-term treatment at both central and peripheral levels. Mice were injected with morphine or saline solution for 8 consecutive days in order to induce morphine analgesic tolerance. On the ninth day, both groups received a final injection of morphine (85%) and d3-morphine (morphine bearing three H; 15%, w/w). Mice were then euthanized and blood, urine, brain and liver samples were collected. LC-MS/MS was used to quantify morphine, its metabolite morphine-3-glucuronide (M3G) and their respective d3-labelled counterparts. We found no significant differences in morphine CNS uptake and metabolism between control and tolerant mice. This suggests that morphine analgesic tolerance is not linked to an increase of morphine glucuronidation into M3G or an alteration of the drug's global BBB permeability. Interestingly, d3-morphine metabolism was decreased compared to morphine without any interference with our study.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The P2X4 receptor is a ligand-gated ion channel that is expressed on a variety of cell types, especially those involved in inflammatory and immune processes. High-throughput screening led to a new class of P2X4 inhibitors with substantial CYP 3A4 induction in human hepatocytes. A structure-guided optimization with respect to decreased pregnane X receptor (PXR) binding was started. It was found that the introduction of larger and more polar substituents on the ether linker led to less PXR binding while maintaining the P2X4 inhibitory potency. This translated into significantly reduced CYP 3A4 induction for compounds

In the published article, there was an error in affiliation "2." Instead of "Global Drug Discovery, Global Therapeutic Research Groups, Gynecological Therapies, Bayer Healthcare, Berlin, Germany", it should be "Laboratoire de Spectrometrie deMasse BioOrganique, IPHC-DSA, CNRS UMR7178 and Universite de Strasbourg, Strasbourg, France." Additionally, the current address of one author has been added as a footnote and is denoted using. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.

Morphine is an analgesic alkaloid used to relieve severe pain, and irreversible binding of morphine to specific unknown proteins has been previously observed. In the brain, changes in the expression of energy metabolism enzymes contribute to behavioral abnormalities during chronic morphine treatment. Creatine kinase B (CK-B) is a key enzyme involved in brain energy metabolism. CK-B also corresponds to the imidazoline-binding protein I2 which binds dopamine (a precursor of morphine biosynthesis) irreversibly. Using biochemical approaches, we show that recombinant mouse CK-B possesses a μM affinity for morphine and binds to morphine in vitro. The complex formed by CK-B and morphine is resistant to detergents, reducing agents, heat treatment and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). CK-B-derived peptides CK-B1–75 and CK-B184–258 were identified as two specific morphine binding-peptides. In vitro, morphine (1–100 μM) significantly reduces recombinant CK-B enzymatic activity. Accordingly, in vivo morphine administration (7.5 mg/kg, i.p.) to mice significantly decreased brain extract CK-B activity compared to saline-treated animals. Together, these results show that morphine strongly binds CK-B and inhibits its activity in vitro and in vivo.

Background Chronic pelvic pain (CPP) is a high burden for patients and society. It affects 15–24% of women in reproductive age and is an area of high unmet medical need. CPP can be caused by a wide range of visceral diseases such as abdominal infections, gastrointestinal or gynaecological diseases like endometriosis. Despite the high medical need for this condition, pharmacological approaches are hampered by the limited number of available methods for the behavioural evaluation of pain in inflammation-driven animal models of pelvic pain. Methods The dynamic weight bearing (DWB) system was used for the evaluation of spontaneous behaviour changes in the zymosan-induced peritonitis mouse model. Inflammatory mediator levels were evaluated in peritoneal lavage and their correlation with the behavioural endpoints was assessed. We evaluated the effect on behavioural endpoints of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib and the Nav1.8 blocker A-803467. Results The presence of a relief posture, characterized by a significantly increased weight distribution towards the front paws, was observed following intraperitoneal injection of zymosan. A positive correlation was detected between PGE2 levels in the peritoneal lavage and DWB endpoints. In addition, zymosan-induced weight bearing changes were reverted by celecoxib and A-803467. Conclusions This study described for the first time the use of DWB as a non-subjective and non-reflexive method for the evaluation of inflammatory-driven abdominal pain in a mouse model.

International audience; Background and purpose: Chronic administration of medication can significantly affect metabolic enzymes leading to physiological adaptations. Morphine metabolism in the liver has been extensively studied following acute morphine treatment, but such metabolic processes in the CNS are poorly characterized. Long-term morphine treatment is limited by the development of tolerance, resulting in a decrease of its analgesic effect. Whether or not morphine analgesic tolerance affects in vivo brain morphine metabolism and blood-brain barrier (BBB) permeability remains a major question. Here, we have attempted to characterize the in vivo metabolism and BBB permeability of morphine after long-term treatment, at both central and peripheral levels.Experimental approach: Male C57BL/6 mice were injected with morphine or saline solution for eight consecutive days in order to induce morphine analgesic tolerance. On the ninth day, both groups received a final injection of morphine (85%) and d3-morphine (morphine bearing three 2 H; 15%, w/w). Mice were then killed and blood, urine, brain and liver samples were collected. LC-MS/MS was used to quantify morphine, its metabolite morphine-3-glucuronide (M3G) and their respective d3-labelled forms.Key results: We found no significant differences in morphine CNS uptake and metabolism between control and tolerant mice. Interestingly, d3-morphine metabolism was decreased compared to morphine without any interference with our study.Conclusions and implications: Our data suggests that tolerance to the analgesic effects of morphine is not linked to increased glucuronidation to M3G or to altered global BBB permeability of morphine.

Background Lithium is widely used to treat bipolar disorders and displays mood stabilizing properties. In addition, lithium relieves painful cluster headaches and has a strong analgesic effect in neuropathic pain rat models. Objectives To investigate the analgesic effect of lithium on the cuff model of neuropathic pain. Methods We used behavioral and pharmacological approaches to study the analgesic effect of a single injection of lithium in wild-type and mu opioid receptor (MOR) null cuffed neuropathic mice. Mass spectrometry and enzyme-linked immunosorbent assay allowed to measure the levels of endogenous MOR agonist beta-endorphin as well as monoamines in brain and plasma samples 4 h after lithium administration. Results A single injection of lithium chloride (100 mg/kg, ip) alleviated mechanical allodynia for 24 h, and this effect was absent in MOR null neuropathic mice. Biochemical analyses highlight a significant increase in beta-endorphin levels by 30% in the brain of lithium-treated mice compared to controls. No variation of beta-endorphin was detected in the blood. Conclusions Together, our results provide evidence that lithium induces a long-lasting analgesia in neuropathic mice presumably through elevated brain levels of beta-endorphin and the activation of MORs.

Endogenous morphine and its derivatives (morphine-6-glucuronide [M6G]; morphine-3-glucuronide [M3G]) are formed by mammalian cells from dopamine. Changes in the concentrations of endogenous morphine have been demonstrated in several pathologies (sepsis, Parkinson's disease, etc.), and they might be relevant as pathological markers. While endogenous morphine levels are detectable using enzyme-linked immunosorbant assay (ELISA), mass spectrometry (MS) analysis was, so far, the only approach to detect and quantify M6G. This study describes the preparation of a specific anti-M6G rabbit polyclonal antibody and its validation. The specificity of this antibody was assessed against 30 morphine-related compounds. Then, a M6G-specific ELISA-assay was tested to quantify M6G in the plasma of healthy donors, morphine-treated, and critically ill patients. The antibody raised against M6G displays a strong affinity for M6G, codeine-6-glucuronide, and morphine-3-6-glucuronide, whereas only weak cross-reactivities were observed for the other compounds. Both M6G-ELISA and LC-MS/MS approaches revealed the absence of M6G in the plasma of healthy donors (controls, n = 8). In all positive donors treated with morphine-patch (n = 5), M6G was detected using both M6G-ELISA and LC-MS/MS analysis. Finally, in a study on critically ill patients with circulating endogenous morphine (n = 26), LC-MS/MS analysis revealed that 73% of the positive-patients (19 of 26), corresponding to high M6G-levels in M6G-ELISA, contained M6G. In conclusion, we show that endogenous M6G can be found at higher levels than morphine in the blood of morphine-naive patients. With respect to the interest of measuring endogenous M6G in pathologies, we provide evidences that our ELISA procedure represents a powerful tool as it can easily and specifically detect endogenous M6G levels.

International audience; Morphine derived from Papaver somniferum is commonly used as an analgesic compound for pain relief. It is now accepted that endogenous morphine, structurally identical to vegetal morphine-alkaloid, is synthesized by mammalian cells from dopamine. Morphine binds mu opioid receptor and induces antinociceptive effects. However, the exact role of these compounds is a matter of debate although different links with infection, sepsis, inflammation, as well as major neurological pathologies (Parkinson's disease, schizophrenia) have been proposed. The present review describes endogenous morphine and morphine derivative discovery, synthesis, localization and potential implications in physiological and pathological processes.

Endometriosis is a chronic, hormone-dependent, inflammatory disease, characterized by the presence and growth of endometrial tissue outside the uterine cavity. It affects 5-10% of the female population of reproductive age and is frequently associated with moderate to severe pain, subfertility, and a marked reduction in health-related quality of life. Here, we propose a new pathophysiological concept of endometriosis, summarizing recent findings in one unifying picture. We propose menstruating tissue as the trigger for inflammatory pain in endometriosis through the activation of innate immune cells and peripheral nerve endings. We speculate how innovative treatment modalities beyond hormonal treatment will improve patients' lives.

In addition to its presence in blood samples from morphine-treated patients and heroin addicts, morphine is endogenously synthesized from dopamine in mammals [1, 2]. However, the physiological relevance of endogenous morphine (eM) remains an open question. Several studies report an increase in eM in blood and urine samples in pathological conditions such as infection, inflammation, bulimia, anorexia and Parkinson's disease [2, 3]. For example, eM concentrations reached on average 2.5 ng ml−1 in the serum of patients suffering from systemic infections (sepsis), whereas healthy donors and control patients displayed no or very low eM concentrations [4]. Therefore, quantification of endogenous and exogenous morphine is of great interest for both clinical and forensic analyses. As both endogenous and exogenous morphine are present at low concentrations, the quantification method implemented must be very sensitive. Besides, no consensus yet exists regarding blood sample preparation for morphine measurement using ELISA. As lithium-heparinate (plasma) and serum samples are both routinely used in clinical practice, we compared the morphine concentrations using these two sampling methods. This study was approved by our institutional review board for human experimentation (CPP no. 08/62-protocol no. IVD1 EUDRACT no. 2008-A01345-50). After informed consent, samples were collected from patients requiring clinical laboratory analyses. Blood from 80 patients was collected in two types of sampling tubes, as follows: (i) for serum analysis, blood was collected in dry tubes (BD, Plymouth, UK; SSTII 377615), and serum was obtained after centrifugation (4°C, 1500g, 10 min); and (ii) for plasma analysis, blood was collected in lithium-heparinate tubes (BD; LH-PSTII 367378, 17 i.u. ml−1) and plasma was recovered after centrifugation (4°C, 1500g, 10 min). Collected serum and plasma were immediately stored at −80°C (for 3 weeks to 3 months). Samples were thawed only once, 15 min prior to ELISA testing. In these conditions, no effect of freezing on morphine concentrations has been noticed. Both plasma and serum morphine concentrations were quantified using a morphine-specific ELISA kit (ref. 213-0480; Immunalysis, Pomona, CA, USA) [4]. No cross-reactivity has been observed for morphine metabolites (morphine-6-glucuronide, morphine-3-glucuronide and codeine) and 75 other compounds (related to eM biosynthesis pathway or not; see also kit's datasheet). The plasma or serum samples were tested in duplicates (40 µl) at 21°C. The coefficient of variation values were between 0% and 8%. All samples with a higher coefficient of variation value were retested in order to obtain a coefficient of variation below or equal to 8%. Morphine standards (0–25 ng ml−1) were diluted in phosphate-buffered saline containing 1% bovine serum albumin (PBS-BSA; pH 7.2; w/v) for serum samples and in PBS-BSA 1% containing lithium-heparinate (17 i.u. ml−1) for plasma samples. The detection limit for morphine was 0.1 ng ml−1. In a set of control experiments, known concentrations of morphine (0.28 and 11 ng ml−1) were diluted in PBS, PBS–lithium-heparinate (17 i.u. ml−1, pH 7.2), PBS–BSA (1%; w/v) or PBS–lithium-heparinate–BSA buffer. Using the ELISA kit, no statistical differences in morphine concentrations were observed (n = 8, Mann–Whitney U-test, P > 0.3) when 0.28 ng ml−1 of morphine was diluted in PBS (0.26 ± 0.03 ng ml−1), PBS–lithium-heparinate [0.26 ± 0.02 ng ml−1; 95% confidence interval (CI) of difference with PBS −0.03 to 0.03], PBS–BSA (0.27 ± 0.02 ng ml−1; 95% CI of difference with PBS −0.04 to 0.02) or PBS–lithium-heparinate–BSA (0.28 ± 0.04 ng ml−1; 95% CI of difference with PBS −0.04 to 0.0). Likewise, no statistical difference (n = 6, Mann–Whitney U-test, P > 0.2) was observed for 11 ng ml−1 of morphine diluted in PBS (11.06 ± 0.58 ng ml−1), PBS–lithium-heparinate (11.42 ± 0.36 ng ml−1; 95% CI of difference with PBS −0.63 to 0.10), PBS–BSA (11.01 ± 0.5 ng ml−1; 95% CI of difference with PBS −0.25 to 0.55) or PBS–lithium-heparinate–BSA (11.36 ± 0.55 ng ml−1; 95% CI of difference with PBS −0.94 to 0.52). This experiment clearly demonstrates that lithium-heparinate and BSA do not introduce a bias in the detection of morphine using this particular ELISA kit. However, when serum and lithium-heparinate tubes were spiked with a known concentration of morphine prior to fresh blood collection (healthy donors, n = 6; 10 ng ml−1), 86 ± 7% (95% CI 79.8–92.2%) of the initial morphine concentration was recovered in plasma samples, but only 42 ± 3% (95% CI 37.9–46.4%) in serum samples (Mann–Whitney U-test, P < 0.01). Finally, 80 patients distributed in the following three groups were tested: (i) healthy donors (n = 16); (ii) morphine-treated patients (morphine skin patch 12–48 h before blood collection, 20 mg day−1, n = 8); and (iii) critically ill patients (n = 56, naive for morphine), including patients with no infection and no inflammation (n = 18), systemic inflammatory response syndromes (n = 8), severe symstemic inflammatory response syndrome (n = 16), sepsis (n = 4), severe sepsis (n = 2) and septic shock (n = 8). In healthy donors, eM was undetectable in both serum and plasma samples. In morphine-treated patients (Figure 1), the mean morphine concentration in serum samples ranged from 3.2 to 31 ng ml−1 (median 8.1 ng ml−1; 95% CI 5.3–20.1 ng ml−1), whereas plasma values ranged from 25.7 to 114.8 ng ml−1 (median 54.8 ng ml−1; 95% CI 41.9–85.0 ng ml−1). On average, morphine concentrations in serum were 78 ± 15% (95% CI 68–88%) lower than in plasma (Wilcoxon signed-rank test, P < 0.05). In critically ill patients, eM concentrations ranged between 0 (not detectable) and 23.6 ng ml−1 in serum samples (median 1.1 ng ml−1; 95% CI 1.9–4.8 ng ml−1) and between 0.15 and 76.3 ng ml−1 (median 2.8 ng ml−1; 95% CI 6.7–15.5 ng ml−1) in plasma samples. Again, serum concentrations of eM were lower (from +13 to −98%; mean 65 ± 32%; 95% CI 57–73%) compared with plasma (Wilcoxon signed-rank test, P < 0.01). The presence of morphine was confirmed by liquid chromatography coupled to tandem mass spectrometry analysis performed on plasma and serum from eight patients not treated with morphine but positive for eM, whereas morphine was not detected in patients negative for eM in ELISA (n = 4) [4]. As expected, no morphine was detected in samples from four healthy donors. Figure 1 Concentrations of morphine in serum expressed as a function of the corresponding morphine concentrations in plasma in critically ill patients (n = 56, triangles) and in morphine-treated patients (n = 8, crosses). Inset shows a higher magnification of ... Our results revealed that morphine concentrations were systematically higher in plasma compared with serum for 61 of 64 patients and thus indicate that lithium-heparinate samples give a more accurate quantification of morphine blood concentrations. The cause of such a difference in morphine quantification between serum and plasma using this specific ELISA kit is currently under investigation by our group and might involve morphine binding to blood proteins [5] other than serum albumin. In line with this possibility, morphine detection in the blood has been shown to be highly dependent on urea concentrations (chaotropic agent), suggesting a link between morphine-binding proteins and morphine bioavailability [5]. Likewise, lithium is also a chaotropic/denaturing agent; therefore, it might explain why this ELISA quantification method for morphine is more efficient in the presence of lithium. The present results clearly demonstrate that to obtain accurate ELISA determinations of exogenous and endogenous morphine concentrations in the blood, the analysis should be carried out on lithium-heparinate plasma samples rather than serum samples.

The superior colliculus is a hub for multisensory integration necessary for visuo-spatial orientation, control of gaze movements and attention. The multiple functions of the superior colliculus have prompted hypotheses about its involvement in neuropsychiatric conditions, but to date, this topic has not been addressed experimentally. We describe experiments on genetically modified mice, the Isl2-EphA3 knock-in line, that show a well-characterized duplication of the retino-collicular and cortico-collicular axonal projections leading to hyperstimulation of the superior colliculus. To explore the functional impact of collicular hyperstimulation, we compared the performance of homozygous knock-in, heterozygous knock-in and wild-type mice in several behavioral tasks requiring collicular activity. The light/dark box test and Go/No-Go conditioning task revealed that homozygous mutant mice exhibit defective response inhibition, a form of impulsivity. This defect was specific to attention as other tests showed no differences in visually driven behavior, motivation, visuo-spatial learning and sensorimotor abilities among the different groups of mice. Monoamine quantification and gene expression profiling demonstrated a specific enrichment of noradrenaline only in the superficial layers of the superior colliculus of Isl2-EphA3 knock-in mice, where the retinotopy is duplicated, whereas transcript levels of receptors, transporters and metabolic enzymes of the monoaminergic pathway were not affected. We demonstrate that the defect in response inhibition is a consequence of noradrenaline imbalance in the superficial layers of the superior colliculus caused by retinotopic map duplication. Our results suggest that structural abnormalities in the superior colliculus can cause defective response inhibition, a key feature of attention-deficit disorders. Electronic supplementary material The online version of this article (doi:10.1007/s00429-014-0745-5) contains supplementary material, which is available to authorized users.

Background Chronic pelvic pain (CPP) is defined as long-lasting and severe pelvic pain persisting over six months in cyclic or non-cyclic chronic manner. Various pathologic conditions like endometriosis, abdominal infections, intra-peritoneal adhesions or infection, underlie CPP which is often the leading symptom of the associated diseases. Pharmacological approaches addressing CPP are hampered by the absence of a straight-forward, objective, and reliable method for the assessment of CPP in rodents. Method In the presented study, the dynamic weight bearing system (DWB) was employed for the first time for the evaluation of pelvic pain in a rat model of LPS-induced peritonitis. Rats were pretreated with the COX-2 inhibitor rofecoxib and PGE2 levels were evaluated in peritoneal lavage. Results DWB analysis revealed that rats treated with LPS showed a relief posture by a significantly increased weight distribution to the front when compared to vehicle-treated animals. This effect was prevented by rofecoxib treatment indicating the sensitivity of the model for pelvic pain related to peritonitis. Analysis of the PGE2 levels in the peritoneal fluid indicated a correlation with the relief posture intensity. Comparison with existing method(s) In contrast to others weight bearing approaches, the use of DWB allows evaluation of spontaneous posture changes as a consequence of pelvic pain. Conclusion Taken together, we were able to show, that DWB combined with LPS-induced peritonitis may deliver a new reliable animal model addressing pelvic pain with high construct validity (peritoneal inflammation), and face validity (pain related relief posture).

Endogenous morphine and its derivatives (morphine-6-glucuronide [M6G]; morphine-3-glucuronide [M3G]) are formed by mammalian cells from dopamine. Changes in the concentrations of endogenous morphine have been demonstrated in several pathologies (sepsis, Parkinson's disease, etc.), and they might be relevant as pathological markers. While endogenous morphine levels are detectable using enzyme-linked immunosorbant assay (ELISA), mass spectrometry (MS) analysis was, so far, the only approach to detect and quantify M6G. This study describes the preparation of a specific anti-M6G rabbit polyclonal antibody and its validation. The specificity of this antibody was assessed against 30 morphine-related compounds. Then, a M6G-specific ELISA-assay was tested to quantify M6G in the plasma of healthy donors, morphine-treated, and critically ill patients. The antibody raised against M6G displays a strong affinity for M6G, codeine-6-glucuronide, and morphine-3-6-glucuronide, whereas only weak cross-reactivities were observed for the other compounds. Both M6G-ELISA and LC-MS/MS approaches revealed the absence of M6G in the plasma of healthy donors (controls, n = 8). In all positive donors treated with morphine-patch (n = 5), M6G was detected using both M6G-ELISA and LC-MS/MS analysis. Finally, in a study on critically ill patients with circulating endogenous morphine (n = 26), LC-MS/MS analysis revealed that 73% of the positive-patients (19 of 26), corresponding to high M6G-levels in M6G-ELISA, contained M6G. In conclusion, we show that endogenous M6G can be found at higher levels than morphine in the blood of morphine-naive patients. With respect to the interest of measuring endogenous M6G in pathologies, we provide evidences that our ELISA procedure represents a powerful tool as it can easily and specifically detect endogenous M6G levels. journal article research support, non-u.s. gov't validation studies 2014 Jan-Feb 2013 07 17 imported

International audience; No abstract available