Non-invasive differentiation of hepatic steatosis and steatohepatitis in a mouse model using nitroxyl radical as an MRI-contrast agent

Drug-induced steatohepatitis is considered more serious than drug-induced hepatic steatosis, so that differentiating between the two is crucial in drug development. In addition, early detection of drug-induced steatohepatitis is considered important since recovery is possible with drug withdrawal. However, no method has been established to differentiate between the two. In the development of drug-induced steatohepatitis, reactive oxygen species (ROS) is excessively generated in the liver. It has been reported that ROS can be monitored with electron spin resonance (ESR) and dynamic nuclear polarization-magnetic resonance imaging (DNP-MRI) by using nitroxyl radicals, which are known to participate in various in vivo redox reactions. The decay/reduction rate, which is an index for monitoring nitroxyl radicals, has been reported to be increased in tissues with excessive ROS levels other than liver, but decreased in methionine choline deficient (MCD) diet-induced steatohepatitis with excess ROS. Therefore, looking to differentiate between drug-induced hepatic steatosis and steatohepatitis, we examined whether the reduction rate decreases in steatohepatitis other than the MCD-diet induced disease and whether the decrease could be detected by MRI. We used STAM™ mice in which hepatic steatosis and steatohepatitis developed sequentially under diabetic conditions. 3-carbamoyl-PROXYL (CmP), one of the nitroxyl radicals, was injected intravenously during the MRI procedure and the reduction rate was calculated. The reduction rate was significantly higher in early steatohepatitis than in hepatic steatosis and the control. Excess ROS in early steatohepatitis was detected by an immunohistochemical marker for ROS. Therefore, it was indicated that the increase or decrease in the reduction rate in steatohepatitis differs depending on the model, and early steatohepatitis could be noninvasively differentiated from hepatic steatosis using CmP in MRI. Since the change in direction of the reduction rate in steatohepatitis in clinical studies could be predicted by confirming the reduction rate in preclinical studies, the present method, which can be used consistently in clinical and preclinical studies, warrants consideration as a candidate monitoring method for differentiating between early drug-induced steatohepatitis and hepatic steatosis in drug development.

Copeptin is associated with microalbuminuria and renal function in the general Japanese population

An association between copeptin (precursor molecule of arginine vasopressin) and markers for renal function has been reported, but data on the Japanese population has been limited. In this study, we investigated whether elevated copeptin levels are associated with microalbuminuria and renal dysfunction in the general Japanese population. A total of 1,262 participants (842 female and 420 male) were enrolled. Multiple regression analysis was performed to assess the association of copeptin levels (logarithm) with estimated glomerular filtration rate (eGFR) and the urine albumin-to-creatinine ratio (UACR) after adjusting for age, BMI, and lifestyle variables. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression methods in which chronic kidney disease (CKD) was the dependent variable. The copeptin levels differed significantly with sex, but were not found to be related to age or the span of time from preceding meal to blood sampling. In female participants, copeptin level was negatively correlated with eGFR (beta = -0.100, p-value = 0.006) and positively correlated with UACR (beta = 0.099, p-value = 0.003). In male participants, a negative correlation (beta = -0.140, p-value = 0.008) was observed for eGFR. In both females and males, those with high copeptin levels had more than double the ORs of CKD (OR = 2.1-2.9) adjusted for CKD-related factors. The present study found elevated copeptin levels to be associated with renal function loss in the Japanese population and microalbuminuria in female. Moreover, it was evident that high copeptin levels are associated with CKD. These results suggest that copeptin could be considered a marker of renal function.

Evaluation of in vivo MRI for detecting midodrine-induced arteritis in rats

There are no specific and sensitive biomarkers for arteritis, and the occurrence of arteritis in nonclinical toxicological studies of a candidate drug makes development of the drug very difficult. However, we showed in a previous study that the high signal intensity region around the artery on magnetic resonance imaging (MRI) could be a candidate biomarker for detection of arteritis. The present study was conducted to clarify the details of midodrine hydrochloride (MH)-induced arteritis lesions and whether arteritis induced by a mechanism other than the vasodilatory effect, which was evaluated in a previous study, could be detected by MRI. MH is a selective peripherally acting alpha-1 adrenergic receptor agonist, known to induce arteritis due to its vasoconstrictor action, but there is not enough information about MH-induced arteritis. Based on the data obtained under multiple dosing conditions, MH was administered subcutaneously to each rat once daily for 2 days at a dose level of 40 mg/kg/day for MRI assessment. The mesenteric arteries were examined using in vivo MRI at 1 day or 7 days after administration of the final dose and examined histopathologically. On the day after the final dose, high signal intensity region around the artery was observed in animals with minimal perivascular lesions confirmed by histopathology and not observed in an animal without histological changes. On the 7th day after the final dose, no abnormality was observed in histopathological examinations and no high signal intensity regions were observed by MRI in any animal. In conclusion, although further investigation is needed to confirm that high signal intensity is a reliable biomarker for humans, it is suggested that high signal intensity around the artery could be a versatile candidate biomarker with high specificity and sensitivity.

Comparison of 1H-magnetic resonance spectroscopy and blood biochemistry as methods for monitoring non-diffuse hepatic steatosis in a rat model

No method of monitoring drug-induced hepatic steatosis has been established, which is a concern in drug development. Hepatic steatosis is divided into diffuse and non-diffuse forms according to the pattern of fat deposition. Diffuse hepatic steatosis was reported as evaluable by ¹H-magnetic resonance spectroscopy (¹H-MRS), which is used as an adjunct to the MRI examination. Blood biomarkers for hepatic steatosis have been also actively investigated. However, there are few reports to conduct ¹H-MRS or blood test in human or animal non-diffuse hepatic steatosis with reference to histopathology. Therefore, to investigate whether non-diffuse hepatic steatosis can be monitored by ¹H-MRS and/or blood samples, we compared histopathology to ¹H-MRS and blood biochemistry in a non-diffuse hepatic steatosis rat model. Non-diffuse hepatic steatosis was induced by feeding rats the methionine choline deficient diet (MCDD) for 15 days. The evaluation sites of ¹H-MRS and histopathological examination were three hepatic lobes in each animal. The hepatic fat fraction (HFF) and the hepatic fat area ratio (HFAR) were calculated from ¹H-MRS spectra and digital histopathological images, respectively. Blood biochemistry analyses included triglycerides, total cholesterol, alanine aminotransferase, and aspartate aminotransferase. A strong correlation was found between HFFs and HFARs in each hepatic lobe (r = 0.78, p < 0.0001) in rats fed the MCDD. On the other hand, no correlation was found between blood biochemistry values and HFARs. This study showed that ¹H-MRS parameters correlated with histopathological changes but blood biochemistry parameters didn't, so that it is suggested that ¹H-MRS has the potential to be a monitoring method for non-diffuse hepatic steatosis in rats fed the MCDD. Given that ¹H-MRS is commonly used in preclinical and clinical studies, ¹H-MRS should be considered a candidate method for monitoring drug-induced hepatic steatosis.

Benefits of laparoscopic surgery for bleeding events in patients with implantable left ventricular assist devices during antithrombotic therapy

Hemorrhagic ovarian cysts (HOCs), a common gynecological disease causing intraabdominal bleeding, can be life threatening in patients undergoing antithrombotic therapy, especially those with left ventricular assist device (LVAD) implantation under strong antithrombotic therapy. We encountered three postLVAD implantation cases with intraabdominal bleeding due to suspected HOCs, which required surgery for hemostasis. Such patients are not only at a higher risk of bleeding but also have restrictions in available surgical incision sites to avoid damaging the LVAD driveline located underneath the abdominal wall. Laparoscopic surgery, which can be performed through minute incisions with flexible site selection, may benefit intraabdominal hemorrhage patients with LVADs.

Sleeping Beauty Transposon Mutagenesis Identifies Genes Driving the Initiation and Metastasis of Uterine Leiomyosarcoma

Uterine leiomyosarcoma (ULMS) is a malignancy, which arises from the uterine smooth muscle. Because of its rarity, aggressive nature, and extremely poor prognosis, the molecular mechanisms driving ULMS remain elusive. To identify candidate cancer genes (CCG) driving ULMS, we conducted an in vivo Sleeping Beauty (SB) transposon mutagenesis screen in uterine myometrium-specific, PTEN knockout, KRAS mutant (PTEN KO/KRAS) mice. ULMS quickly developed in SB PTEN KO/KRAS mice, but not in PTEN KO/KRAS mice, demonstrating the critical importance of SB mutagenesis for driving ULMS in this model. Subsequent sequencing of SB insertion sites in these tumors identified 19 ULMS CCGs that were significantly enriched in known cancer genes. Among them, Zfp217 and Sfmbt2 functioned at early stages of tumor initiation and appeared to be oncogenes. Expression of ZNF217, the human homolog of ZFP217, was shown to be elevated in human ULMS compared with paired normal uterine smooth muscle, where it negatively correlated with patient prognosis. Inhibition of ZNF217 suppressed, whereas overexpression induced, proliferation, survival, migration, and stemness of human ULMS. In a second ex vivo ULMS SB metastasis screen, three CCGs were identified that may drive ULMS metastasis to the lung. One of these CCGs, Nrd1 (NRDC in humans), showed stronger expression in human metastatic tumors compared with primary ULMS and negatively associated with patient survival. NRDC knockdown impaired migration and adhesion without affecting cell proliferation, whereas overexpression had the opposite effect. Together, these results reveal novel mechanism driving ULMS tumorigenesis and metastasis and identify ZNF217 and NRDC as potential targets for ULMS therapy. SIGNIFICANCE: An in vivo Sleeping Beauty transposon mutagenesis screen identifies candidate cancer genes that drive initiation and progression of uterine leiomyosarcoma and may serve as therapeutic targets.

Ubiquitin specific peptidase 32 acts as an oncogene in epithelial ovarian cancer by deubiquitylating farnesyl-diphosphate farnesyltransferase 1

Epithelial ovarian cancer (EOC) is the seventh most common cancer worldwide and the deadliest gynecological malignancy because of its aggressiveness and high recurrence rate. To discover new therapeutic targets for EOC, we combined public EOC microarray datasets with our previous in vivo shRNA screening dataset. The top-ranked gene ubiquitin specific peptidase 32 (USP32), coding a deubiquitinating enzyme, is a component of the ubiquitin proteasome system. Clinically, USP32 is expressed in primary ovarian cancer, especially in metastatic peritoneal tumors, and negatively impacts the survival outcome. USP32 regulates proliferative and epithelial mesenchymal transition capacities that are associated with EOC progression. Proteomic analysis identified farnesyl-diphosphate farnesyltransferase 1 (FDFT1) as a novel substrate of USP32 that is an enzyme in the mevalonate pathway, essentially associated with cell proliferation and stemness. USP32 and FDFT1 expression was higher in tumor spheres than in adherent cells. Inhibition of USP32, FDFT1, or mevalonate pathway considerably suppressed tumor sphere formation, which was restored by adding squalene, a downstream product of FDFT1. These findings suggested that USP32-FDFT1 axis contributes to EOC progression, and could be novel therapeutic targets for EOC treatment.

Corrigendum: An Evolutionarily Threat-Relevant Odor Strengthens Human Fear Memory

[This corrects the article DOI: 10.3389/fnins.2020.00255.].

An Evolutionarily Threat-Relevant Odor Strengthens Human Fear Memory

Olfaction is an evolutionary ancient sense, but it remains unclear to what extent it can influence routine human behavior. We examined whether a threat-relevant predator odor (2-methyl-2-thiazoline) would contextually enhance the formation of human fear memory associations. Participants who learned to associate visual stimuli with electric shock in this predator odor context later showed stronger fear responses to the visual stimuli than participants who learned in an aversiveness-matched control odor context. This effect generalized to testing in another odor context, even after extinction training. Results of a separate experiment indicate that a possible biological mechanism for this effect may be increased cortisol levels in a predator odor context. These results suggest that innate olfactory processes can play an important role in human fear learning. Modulatory influences of odor contexts may partly explain the sometimes maladaptive persistence of human fear memory, e.g., in post-traumatic stress disorders.

Classification and characterisation of brain network changes in chronic back pain: A multicenter study

Background. Chronic pain is a common, often disabling condition thought to involve a combination of peripheral and central neurobiological factors. However, the extent and nature of changes in the brain is poorly understood.

Methods. We investigated brain network architecture using resting-state fMRI data in chronic back pain patients in the UK and Japan (41 patients, 56 controls), as well as open data from USA. We applied machine learning and deep learning (conditional variational autoencoder architecture) methods to explore classification of patients/controls based on network connectivity. We then studied the network topology of the data, and developed a multislice modularity method to look for consensus evidence of modular reorganisation in chronic back pain.

Results. Machine learning and deep learning allowed reliable classification of patients in a third, independent open data set with an accuracy of 63%, with 68% in cross validation of all data. We identified robust evidence of network hub disruption in chronic pain, most consistently with respect to clustering coefficient and betweenness centrality. We found a consensus pattern of modular reorganisation involving extensive, bilateral regions of sensorimotor cortex, and characterised primarily by negative reorganisation - a tendency for sensorimotor cortex nodes to be less inclined to form pairwise modular links with other brain nodes. Furthermore, these regions were found to display increased connectivity with the pregenual anterior cingulate cortex, a region known to be involved in endogenous pain control. In contrast, intraparietal sulcus displayed a propensity towards positive modular reorganisation, suggesting that it might have a role in forming modules associated with the chronic pain state.

Conclusion. The results provide evidence of consistent and characteristic brain network changes in chronic pain, characterised primarily by extensive reorganisation of the network architecture of the sensorimotor cortex.

Frequency of mental disorders among chronic pain patients with or without fibromyalgia in Japan

Aim

To explore the characteristics of psychiatric morbidity in chronic pain patients who present with or without fibromyalgia.

Methods

Patients are referred to our chronic pain clinic from primary medical institutions, as we are a secondary medical institution. Although some patients have chronic pain, they have no clear organic disorder such as rheumatoid arthritis to account for the pain. Among the 367 new patients seen during the period from March 2009 to August 2012, 347 patients underwent psychiatric evaluation in face‐to‐face interviews with mental health specialists before a physical examination.

Results

Of the 347 patients examined, at least one psychiatric diagnosis was made for 94.6%. The average number of DSM‐IV‐TR diagnoses was 1.46 in the 330 chronic pain patients who had at least one psychiatric diagnosis. The breakdown of the number of psychodiagnoses was one in 60.8%, two in 27.1%, three in 4.9%, and more than three in 2.3% chronic pain patients with or without fibromyalgia. In fibromyalgia patients, the highest relative frequencies were found for somatoform disorders (76%), followed by dysthymic disorder (17%) and major depressive disorder (15%). In patients without fibromyalgia, the highest relative frequencies were found for somatoform disorders (64%), followed by major depressive disorder (15%) and dysthymic disorder (14%). Psychiatric disorders were found in 96.9% of fibromyalgia patients, and in 93.5% of chronic pain patients without fibromyalgia in Japan (no significant difference using chi‐square test).

Conclusion

Results show that chronic pain patients with or without fibromyalgia are extremely likely to be diagnosed with a psychiatric disorder.

Psychodiagnoses of fibromyalgia patients and chronic pain patients without fibromyalgia.

Moderate sedation induced by general anaesthetics disrupts audio-spatial feature binding with sustained P3 components in healthy humans

Feature binding is considered to be the basis for conscious stimulus perception, while anaesthetics exert a gradient effect on the loss of consciousness (LOC). By integrating these two streams of research, the present study assessed the effect of two anaesthetic agents (i.e. propofol and midazolam) on audio-spatial feature binding. We also recorded the electrophysiological activity of the frontal channels. Using pharmacokinetic simulation, we determined the effect-site concentration (Ce) of the anaesthetics at loss of response to verbal command and eyelash reflex. We subsequently adjusted Ce to 75%, 50% and 25% of Ce-LOC to achieve deep, moderate and light sedation, respectively. Behavioural results showed that moderate sedation selectively disrupted feature binding. The frontal channels showed a P3 component (350-600 ms peristimulus period) following the presentation of audio-spatial stimuli at baseline and under moderate and light sedations. Critically, the late event-related potential component (600-1000 ms) returned to the pre-activated level (0-350 ms) at baseline and under light sedation but was sustained under moderate sedation. We propose that audio-spatial feature binding may require the presence of a P3 component and its subsequent and sufficient decline, as under anaesthetic-induced moderate sedation the P3 component was sustained and featured binding was impaired.

Abstract 2341: Sleeping Beauty transposon mutagenesis screen identifies cancer genes of uterine leiomyosarcoma driving sarcomagenesis and lung metastasis

Introduction

Uterine leiomyosarcoma (ut-LMS) is one of the most aggressive malignancies with extremely poor prognosis. The 5-year survival rate is 0-20% for patients with tumors beyond uterus and 50% for even early stage patients due to high hematological metastatic potential. Because of its rarity, large-scale genetic profiling could not be done and thus its molecular mechanisms remain largely unknown. To solve this problem, we conducted in vivo sleeping beauty (SB) transposon mutagenesis screen and identified the key genetic drivers of ut-LMS.

Methods

We crossed Amhr2-Cre knock-in mice, transposon transgenic mice (T2Onc2), SB transposase knock-in mice (Rosa-LSL-SBase), Pten floxed mice, and Kras G12D knock-in mice, generating experimental mice (Amhr2-Cre Tg/+;T2Onc2 Tg/+;SBase KI/+;Pten fl/fl;Kras LSL-G12D/+) and control mice (Amhr2-Cre Tg/+; Pten fl/fl;Kras LSL-G12D/+). The experimental mice have homozygous deletion of Pten, constitutive activation of Kras and SB transposon mobilization in uterine smooth muscle cells. Fifty-nine experimental mice and 14 control mice were aged until moribund.

Results

All of the experimental mice died of multiple uterine tumors by 2 months of age, while none of the control mice developed uterine tumors. These uterine tumors were histologically diagnosed as ut-LMS by their morphology and immunohistochemical positivity of desmin and alpha-SMA. These results clearly indicated that transposon mutagenesis was required for sarcomagenesis of ut-LMS. To identify genes mutagenized by SB transposon in these tumors, we performed splink HiSeq sequence of gDNA from 80 primary uterine tumors and 24 normal uterus of mice with uterine tumors. Gene-centric common insertion site analysis (gCIS) identified 19 CIS genes in primary uterine tumors but no CIS genes

in normal uterus, indicating the selective enrichment of transposon insertions in cancer genes in tumors. By further focusing on the transposon insertions with high sequence read counts, we identified trunk mutations driving sarcomagenesis that include inactivating mutations of NF1 and activating mutations of one of zinc fingers gene family. Its inhibition via siRNA in human ut-LMS cell lines, SK-LMS1, SK-UT1, and SKN, impaired cell proliferation and sphere formation, suggesting the importance of this gene for the survival of ut-LMS.

Next, to identify the metastatic drivers of ut-LMS, we induced the lung metastasis by tail vein injection of 9 cell lines established from SB uterine tumors. After the sequential in vivo passage of metastatic SB tumors, we have obtained 50 lung metastatic tumors in immunocompetent mice. Sequencing and gCIS analysis of 50 lung metastases identified 3 potential driver genes of lung metastases.

Conclusion

SB mutagenesis screen discovers multiple cancer genes of ut-LMS driving sarcomagenesis and lung metastasis.

Citation Format: Michiko Kodama, Takahiro Kodama, Justin Y. Newberg, Jean C. Tien, Roberto Rangel, Aya Nakae, Kae Hashimoto, Seiji Mabuchi, Kenjiro Sawada, Tadashi Kimura, Nancy A. Jenkins, Neal G. Copeland. Sleeping Beauty transposon mutagenesis screen identifies cancer genes of uterine leiomyosarcoma driving sarcomagenesis and lung metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2341.

The Relationships Between Pain-Catastrophizing Subcomponents and Multiple Pain-Related Outcomes in Japanese Outpatients with Chronic Pain: A Cross-Sectional Study

OBJECTIVES

The present study sought to examine associations between the pain-catastrophizing subcomponents and multiple pain-related outcomes in Japanese individuals with chronic pain.

METHODS

A cross-sectional study design was employed with 213 chronic pain outpatients. The participants were recruited from 3 units at a university hospital and from a pain clinic at a municipal hospital. Study measures were used to assess pain catastrophizing, anxiety, depression, pain interference, and pain severity.

RESULTS

Path analysis with multiple pain-related outcomes while controlling for age and gender revealed that the Helplessness subcomponent was associated with anxiety, depression, pain interference, and pain severity. The Magnification subcomponent was related to anxiety and depression, and the Rumination subcomponent accounted for the variance of pain interference.

DISCUSSION

The present results suggested the important role of helplessness across cultural backgrounds. It also provides guidance on the application of cognitive behavioral techniques for chronic pain management in Japan.

Classification and characterisation of brain network changes in chronic back pain: A multicenter study

Background. Chronic pain is a common, often disabling condition thought to involve a combination of peripheral and central neurobiological factors. However, the extent and nature of changes in the brain is poorly understood. Methods. We investigated brain network architecture using resting-state fMRI data in chronic back pain patients in the UK and Japan (41 patients, 56 controls), as well as open data from USA. We applied machine learning and deep learning (conditional variational autoencoder architecture) methods to explore classification of patients/controls based on network connectivity. We then studied the network topology of the data, and developed a multislice modularity method to look for consensus evidence of modular reorganisation in chronic back pain. Results. Machine learning and deep learning allowed reliable classification of patients in a third, independent open data set with an accuracy of 63%, with 68% in cross validation of all data. We identified robust evidence of network hub disruption in chronic pain, most consistently with respect to clustering coefficient and betweenness centrality. We found a consensus pattern of modular reorganisation involving extensive, bilateral regions of sensorimotor cortex, and characterised primarily by negative reorganisation - a tendency for sensorimotor cortex nodes to be less inclined to form pairwise modular links with other brain nodes. In contrast, intraparietal sulcus displayed a propensity towards positive modular reorganisation, suggesting that it might have a role in forming modules associated with the chronic pain state. Conclusion. The results provide evidence of consistent and characteristic brain network changes in chronic pain, characterised primarily by extensive reorganisation of the network architecture of the sensorimotor cortex.

Effects of sedation on subjective perception of pain intensity and autonomic nervous responses to pain: A preliminary study

Rather than relying solely on subjective pain evaluation using means such as the visual analogue scale (VAS), in clinical situations it is possible to observe evoked responses of the autonomic nervous system (ANS) as objective indicators. Few studies, however, have reported these relationships under finely controlled sedation. 16 healthy male participants were administrated in intravenous sedation with either propofol or midazolam randomly. We initially determined, using pharmacokinetic simulation, the effect-site concentration (Ce) of anaesthetic at loss of response to verbal command and eyelash reflex (Ce-LOR). Then subsequently adjusted Ce to 75%, 50%, and 25% of Ce-LOR to achieve deep, moderate, and light sedation. At awake control state and each sedation level, a noxious electrical stimulation was applied three times at the right forearm, an average pain intensity of the three stimuli was rated on a VAS (0–10). Changes in the peripheral perfusion index measured by oximetry were used as an indicator of ANS response. We analyzed the influence of sedation level on VAS and ANS responses compared to the awake control state. While ANS responses were similar in all conditions, VAS was statistically significantly lower in moderate (5.6±0.6, p <0.005) or deep (5.3±0.6, p <0.001) sedation than in the awake state (7.2±0.4). This study revealed that even when the ANS responds similarly to the same stimulation, subjective pain perception is attenuated by sedation. A cerebral mechanism other than that of the brainstem might determine subjective pain intensity.

Effects of a Hypnotic Induction and an Unpleasantness-Focused Analgesia Suggestion on Pain Catastrophizing to an Experimental Heat Stimulus: A Preliminary Study

Pain catastrophizing is associated with greater levels of pain. While many studies support the efficacy of hypnosis for pain, the effect on pain catastrophizing remains unclear. The present study evaluated the effect of hypnosis on pain catastrophizing using experimental heat stimulation. Twenty-two pain patients engaged in 3 conditions: baseline (no suggestion), hypnotic induction, and hypnotic induction plus analgesia suggestion. Participants with higher baseline pain showed a significant reduction in rumination following hypnotic induction plus analgesia suggestion and significant reductions in pain due to both the hypnotic induction alone and the hypnotic induction plus analgesia suggestion. The findings suggest that unpleasantness-focused hypnotic analgesia reduces pain via its effect on the rumination component of pain catastrophizing.

Go-sha-jinki-Gan (GJG) ameliorates allodynia in chronic constriction injury-model mice via suppression of TNF-α expression in the spinal cord

Background

Alternative medicine is noted for its clinical effect and minimal invasiveness in the treatment of neuropathic pain. Go-sha-jinki-Gan, a traditional Japanese herbal medicine, has been used for meralgia and numbness in elderly patients. However, the exact mechanism of GJG is unclear. This study aimed to investigate the molecular mechanism of the analgesic effect of GJG in a chronic constriction injury model.

Results

GJG significantly reduced allodynia and hyperalgesia from the early phase (von Frey test, p < 0.0001; cold-plate test, p < 0.0001; hot-plate test p = 0.011; two-way repeated measures ANOVA). Immunohistochemistry and Western blot analysis revealed that GJG decreased the expression of Iba1 and tumor necrosis factor-α in the spinal cord. Double staining immunohistochemistry showed that most of the tumor necrosis factor-α was co-expressed in Iba1-positive cells at day 3 post-operation. GJG decreased the phosphorylation of p38 in the ipsilateral dorsal horn. Moreover, intrathecal injection of tumor necrosis factor-α opposed the anti-allodynic effect of GJG in the cold-plate test.

Conclusions

Our data suggest that GJG ameliorates allodynia in chronic constriction injury model mice via suppression of tumor necrosis factor-α expression derived from activated microglia. GJG is a promising drug for the treatment of neuropathic pain induced by neuro-inflammation.

Sensory cognitive abnormalities of pain in autism spectrum disorder: a case-control study

BACKGROUND

The Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) recently included sensory processing abnormalities in the diagnostic criteria for individuals with autism spectrum disorder (ASD). However, there is no standard method for evaluating sensory abnormalities in individuals with ASD.

METHODS

Fifteen individuals with ASD and 15 age- and sex-matched controls were enrolled in this study. We compared objective pain sensitivity by measuring the pain detection threshold and pain tolerance to three different stimuli (electricity, heat, and cold). Then, we compared both subjective pain sensitivity, assessed by the visual analog scale (VAS), and quality of pain, assessed by the short-form McGill Pain Questionnaire (SF-MPQ), to determine the maximum tolerable pain intensities of each stimulation.

RESULTS

The pain detection threshold and pain tolerance of individuals with ASD were not impaired, indicating that there were no differences in the somatic perception of pain between groups. However, individuals with ASD were hyposensitive to subjective pain intensity compared to controls (VAS; electrical: p = 0.044, cold: p = 0.011, heat: p = 0.042) and hyposensitive to affective aspects of pain sensitivity (SF-MPQ; electrical: p = 0.0071, cold: p = 0.042).

CONCLUSIONS

Our results suggest that the cognitive pathways for pain processing are impaired in ASD and, furthermore, that our methodology can be used to assess pain sensitivity in individuals with ASD. Further investigations into sensory abnormalities in individuals with ASD are needed to clarify the pathophysiologic processes that may alter sensory processing in this disorder.

A NEURAL BIOMARKER FOR CHRONIC PAIN BASED ON DECODED BRAIN NETWORKS

The lack of a biomarker for chronic pain remains an important impediment to clinical and translational pain research. The problem stems from the multiple parallel but subtle abnormalties thought to represent the chronic pain state, yielding the emerging view of chronic pain as a ‘network disorder’. This suggests analysis approaches that aim to identify distributed patterns of data (multivariate, machine learning methods) might offer the best opportunity to discover biomarkers. Here, we performed a multi-center functional brain imaging study to record state functional brain networks resting in 41 patients with chronic back pain and 33 healthy control subjects. We calculated with functional covariance matrix from 160 regions of interest, and used Sparse Multinomial Logistic Regression to classify subjects as patient or control using a leave-one-out cross validation. Diagnostic accuracy was 91.9%, with sensitivity and specificity 90.2% and 93.9% respectively. We then used graph theoretic measures to characterise the pattern of network differences between the groups, and showed that the chronic pain state was associated with disrupted network ‘assortativity’. These data provide evidence to support an accurate functional biomarker of chronic pain, and open the door to the development of translatable biomarkers using similar methodologies in animals.

Antinociceptive effects of mirtazapine, pregabalin, and gabapentin after chronic constriction injury of the infraorbital nerve in rats

AIMS

To clarify the antiallodynic effects of the α2-adrenergic receptor antagonist mirtazapine compared with those of gabapentin and pregabalin in a rat model of orofacial neuropathic pain.

METHODS

Mirtazapine (10, 30, and 100 μg), gabapentin (10, 30, and 100 μg), and pregabalin (3, 10, and 30 μg) were administered intrathecally to eight male Sprague-Dawley rats with orofacial neuropathic pain induced by chronic constriction injury of the infraorbital nerve that had been carried out 2 weeks previously. Stimulation using von Frey filaments (1.0 to 15.0 g) applied to skin innervated by the injured infraorbital nerve enabled the measurement of mechanical thresholds 0 to 180 minutes after drug injection. Time-course data for the dose-response effects were analyzed using two-way analysis of variance and the posthoc Tukey-Kramer multiple-comparison test.

RESULTS

Intrathecal administration of not only gabapentin and pregabalin but also mirtazapine reversed the lowered mechanical nociceptive thresholds produced by the nerve injury. The ED50 (95% confidence interval) was (in μg) 49.00 (39.71-58.29) for mirtazapine, 54.84 (46.12-63.56) for gabapentin, and 13.47 (11.24-15.69) for pregabalin.

CONCLUSION

Intraspinal administration of either mirtazapine, gabapentin, or pregabalin reverses the lowered facial mechanical thresholds produced in a rat model of trigeminal neuropathic pain.

Age-related and sex-related changes in perfusion index in response to noxious electrical stimulation in healthy subjects

Background

Even though pain is a subjective phenomenon, its objective evaluation in humans is important because subjects requiring pain evaluation may be unable to describe their pain intensity because of decreased awareness or impaired cognitive function. Previous reports indicate that the perfusion index (PI), which is calculated from pulse oximeter waveforms, has some utility in assessing pain. However, age-associated and sex-associated differences in change of PI have hitherto not been evaluated for assessment of pain. Therefore, we aimed to estimate the utility of age-related differences in PI change among healthy volunteers subjected to electrical stimulation.

Methods

We measured PI and pulse rate in 70 healthy volunteers exposed to gradually increasing electrical stimulation. The subjects were classified into four groups, ie, young men, young women, aged men, and aged women. Stimulation was stopped when subjects reached their pain tolerance threshold. The average PI and pulse rate were calculated 10 seconds before and after electrical stimulation and compared across the four groups. Changes in PI and pulse rate were analyzed using the paired t-test.

Results

The PI was significantly decreased in response to pain stimulation in young men (P<0.0001), young women (P=0.0002), and aged men (P=0.0158). However, aged women failed to show significant changes in PI before or after stimulation. The pulse rate was not significantly altered in any of the groups.

Conclusion

PI may be an independent parameter reflecting the perception of noxious stimuli and could be used for objective evaluation of pain perception in healthy volunteers, except when it is used for pain evaluation in elderly women.

A meta-analysis of hypnosis for chronic pain problems: a comparison between hypnosis, standard care, and other psychological interventions

Hypnosis is regarded as an effective treatment for psychological and physical ailments. However, its efficacy as a strategy for managing chronic pain has not been assessed through meta-analytical methods. The objective of the current study was to conduct a meta-analysis to assess the efficacy of hypnosis for managing chronic pain. When compared with standard care, hypnosis provided moderate treatment benefit. Hypnosis also showed a moderate superior effect as compared to other psychological interventions for a nonheadache group. The results suggest that hypnosis is efficacious for managing chronic pain. Given that large heterogeneity among the included studies was identified, the nature of hypnosis treatment is further discussed.

The influence of working memory capacity on experimental heat pain

Pain processing and attention have a bidirectional interaction that depends upon one's relative ability to use limited-capacity resources. However, correlations between the size of limited-capacity resources and pain have not been evaluated. Working memory capacity, which is a cognitive resource, can be measured using the reading span task (RST). In this study, we hypothesized that an individual's potential working memory capacity and subjective pain intensity are related. To test this hypothesis, we evaluated 31 healthy participants' potential working memory capacity using the RST, and then applied continuous experimental heat stimulation using the listening span test (LST), which is a modified version of the RST. Subjective pain intensities were significantly lower during the challenging parts of the RST. The pain intensity under conditions where memorizing tasks were performed was compared with that under the control condition, and it showed a correlation with potential working memory capacity. These results indicate that working memory capacity reflects the ability to process information, including precise evaluations of changes in pain perception.

PERSPECTIVE

In this work, we present data suggesting that changes in subjective pain intensity are related, depending upon individual potential working memory capacities. Individual working memory capacity may be a phenotype that reflects sensitivity to changes in pain perception.

Serotonin 2C receptor alternative splicing in a spinal cord injury model

Spinal cord injury can have debilitating consequences, commonly resulting in motor dysfunction below the lesion site and the development of chronic pain syndromes. The serotonin pathway is important for inhibiting noxious stimuli and facilitating motor function after spinal cord injury. The serotonin 2C receptor (5HTR2C) has several characteristic features, and is regulated by the amount of serotonin 2C receptor as well as RNA editing and alternative splicing. In this study, we used a rat model of spinal contusion injury to investigate the relationship between the pain threshold and 5HTR2C alternative splicing. The pain threshold was assessed using mechanical stimulation with von Frey filaments. We then used real-time PCR to examine the RNA levels of 5HTR2C in three sections of the spinal cord: the rostral, injury-core, and caudal positions. On postoperative day 12, the pain threshold in injured rats was significantly reduced compared with sham-operated and naïve rats. The total 5HTR2C levels were significantly lower in injured rats than in naïve rats at all positions, and significantly lower in injured rats compared with sham-operated rats at injury-core and caudal positions. The ratio of exon Vb-skipped nonfunctional 5HTR2C mRNA to total 5HTR2C was significantly higher in injured rats compared with naïve rats at the injury-core and caudal positions, and significantly higher in injured rats compared with sham-operated rats at the caudal position. These results indicate that spinal contusion injury, which causes neuropathic pain, induces serotonergic dysfunction. This dysfunction appears to be mediated by decreased 5HTR2C mRNA expression, and alternative splicing. These results confirm the importance of considering splice variants when examining 5HTR2C.

Recovery of motoneuron and locomotor function after spinal cord injury depends on constitutive activity in 5-HT2C receptors

Muscle paralysis after spinal cord injury is partly caused by a loss of brainstem-derived serotonin (5-HT), which normally maintains motoneuron excitability by regulating crucial persistent calcium currents. Here we examine how over time motoneurons compensate for lost 5-HT to regain excitability. We find that, months after a spinal transection in rats, changes in post-transcriptional editing of 5-HT2C receptor mRNA lead to increased expression of 5-HT2C receptor isoforms that are spontaneously active (constitutively active) without 5-HT. Such constitutive receptor activity restores large persistent calcium currents in motoneurons in the absence of 5-HT. We show that this helps motoneurons recover their ability to produce sustained muscle contractions and ultimately enables recovery of motor functions such as locomotion. However, without regulation from the brain, these sustained contractions can also cause debilitating muscle spasms. Accordingly, blocking constitutively active 5-HT2C receptors with SB206553 or cyproheptadine, in both rats and humans, largely eliminates these calcium currents and muscle spasms, providing a new rationale for antispastic drug therapy.

5-HT2C receptor agonists attenuate pain-related behaviour in a rat model of trigeminal neuropathic pain

Peripheral branches of the trigeminal nerve may be damaged during maxillofacial injury or surgical procedures and trigeminal trauma may induce severe pain that is very challenging to treat. Chronic constriction injury to the infraorbital nerve (ION-CCI) by loose ligatures has proven a useful model for some types of trigeminal neuropathic pain disorder. Using ION-CCI rats, we examined the antiallodynic effects of intrathecally administered agents which are selective for 5-HT2C receptors. Allodynia was evaluated by applying von Frey filaments to skin innervated by the injured ION. Dose-dependent antiallodynic effects followed administration of three 5-HT2C receptor agonists, 6-chloro-2-(1-piperazinyl)-pyrazine (MK212: 10, 30, and 100 μg); (S)-2-(chloro-5-fluoro-indol-l-yl)-1-methyamine fumarate (RO 60-0175: 10, 30, and 100 μg); (AaR)-8,9-dichloro-2,3,4,4a-tetrahydro-1H-pyrazino[1,2-a]quinoxalin-5(6H)-one (WAY-161503: 10, 30, and 100 μg). ED50 values for antiallodynic effects of MK212, RO 60-0175, and WAY-161503 were 39.62, 46.67, and 51.22 μg, respectively. Intrathecal administration of the 5-HT2C receptor antagonist, 8-[5-2,4-dimethoxy-5-(4-trifluoromethylphenylsulphonamido)phenyl-5-oxopentyl]-1,3,8-triazaspiro[4,5]decane-2,4-dione (RS-102221: 30 μg) did not alter the mechanical threshold. Intrathecal pretreatment with RS-102221 (10 and 30 μg) reduced the antiallodynic effects of the highest dose of 5-HT2C agonists. These results indicated that, in this rat model, the 5-HT2C receptor plays a role in spinal inhibition of trigeminal neuropathic pain.

Comparing methods of detection and quantitation of RNA editing of rat glycine receptor alpha3

Background: Recently, it has become evident that RNA editing-related changes are important in the modulation of neuronal information processing. Alternatively edited transcripts, when meagerly present, are hard to detect. Significant functional consequences may result, however, from small differences in editing efficiency. Moreover, it is difficult to evaluate the ratio of edited transcripts. The glycine receptor alpha3 subunit (GlyR alpha3) is expressed in the spinal cord, and transcripts of GlyR alpha3 are susceptible to RNA editing. The physiological role of this editing is still unclear. To analyze changes in RNA editing in various animal models, we need reliable and practical ways to detect and quantitate GlyR alpha3 RNA editing.

Results: We identified and assessed different ways of detecting edited RNA transcripts, including direct sequencing, denaturing high performance chromatography (DHPLC), allele-specific real-time PCR with TaqMan probes, and PCR with allele-specific primers. Using PCR with allele-specific primers on standard PCR products for edited and nonedited GlyR alpha3, we were able to detect as little as a 0.5% incidence of edited transcripts. We were able to detect a 5% incidence of RNA editing using direct sequencing and 2% using DHPLC. We could accurately determine the ratio of edited to non-edited RNA using DHPLC, direct sequencing, and allele-specific real-time PCR with TaqMan probes.

Conclusion: We demonstrated exact and sensitive methods of detecting RNA editing. In prepared samples, we showed means of quantitating the incidence of editing of a particular site. The demonstrated methodologies should be very useful when extended to the evaluation of other types of RNA editing and single base mutations.

The role of RNA editing of the serotonin 2C receptor in a rat model of oro-facial neuropathic pain

We examined whether infraorbital nerve injury affected the RNA editing efficiency of the serotonin (5HT) 2C receptor in the cervical spinal cord, in association with increased pain thresholds, and whether a 5HT reuptake inhibitor (fluvoxamine; Depromel, Meiji Seika, Tokyo, Japan) altered this editing. Accordingly, we injured rats with an infraorbital nerve loose ligation and examined the pain thresholds, mRNA and mRNA editing of the 5HT2C receptor. We evaluated changes in mRNA editing and 5HT2C mRNA expression using cloning along with sequence analysis and quantitative reverse transcription-polymerase chain reaction to compare samples taken at post-injury day 28 from spinal cord sites, including the trigeminal nucleus caudalis, in naive, sham and injured rats (groups of each type had also received fluvoxamine). 5HT2C receptor expression was maintained post-injury. The RNA editing efficiency was statistically significantly lower at molecular sites A and B in ipsilateral spinal cord samples from injured rats than in bilateral samples from naive and sham rats, and in contralateral samples from injured rats. After injury, the proportional presence of two receptor isoforms changed, i.e. statistically significantly less VNV and significantly more INV and ISV. The proportions reverted after fluvoxamine administration. The post-injury change might be evidence of a functional adaptation mechanism that increases the expression of 5HT2C mRNA isoforms that encode receptors that are more sensitive to 5HT. This would activate the brainstem-spinal descending 5HT systems and, in effect, suppress nociceptive signals from primary afferent neurons to the spinal trigeminal nucleus caudalis.

Arytenoid dislocation after cardiac surgery

Occurring most usually as complications of upper aerodigestive tract instrumentation during endotracheal intubation or extubation, arytenoid cartilage dislocation and arytenoid subluxation are uncommon laryngeal injuries. Their precise cause, however, is usually difficult to determine. We encountered arytenoid dislocation following cardiac surgery requiring the use of transesophageal echocardiography (TEE). This case prompted us to review some of the mechanisms of injury to the cricoarytenoid joint. We conclude that even very subtle force may dislocate the arytenoid cartilage. We speculate that careless insertion of a TEE probe is mechanically capable of causing arytenoid dislocation and arytenoid subluxation. As ideal tools for intra-operative cardiovascular monitoring, TEE probes are increasingly being used routinely during cardiovascular surgery. So far, arytenoid cartilage dislocation and subluxation following TEE probe insertion have been reported rarely, but complications caused by TEE may increase in the near future. We wish to emphasize the pathophysiological risks of TEE monitoring and other procedures associated with anesthesia, and the need for a proper explanation to achieve informed consent before carrying out TEE monitoring during cardiac surgeries.

[Teaching the use of fiberoptic intubation in anesthetized patients]

BACKGROUND

Fiberoptic bronchoscope (FOB)-guided intubation is an important and useful technique for unanticipated difficult airway in anesthetized patients. However, many staff anesthesiologists seemed to find it difficult to perform. We speculated that it was because they had not been well trained in the technique. We worked out an easy method for FOB-guided intubation. We had our residents try our method and measured the elapsed time in introducing FOB from the mouth to the tracheal carina.

METHODS

After IRB approval and having obtained informed consent, we enrolled twenty residents with experience of two to four years and twenty patients scheduled for thoracic surgery. After induction of anesthesia, we inserted a Berman airway and let the residents try to introduce FOB from the mouth to the tracheal carina. Staff anesthesiologists gave verbal advises only by watching the video image and we measured the elapsed time.

RESULTS

The elapsed time was 83+/-43 sec (mean+/-SD). Although three residents required interruptions for ventilation during their trials, they were able to accomplish their missions in their second or third attempt. In all cases, Sp02 was kept at 100% throughout the trials.

CONCLUSIONS

We showed that our method helped anesthesiologists to master FOB-guided intubation.

[A case report of spontaneous rupture of bilateral lumbar artery in a patient with von Recklinghausen disease]

Vascular complications in von Recklinghausen disease are rare, especially spontaneous rupture of a major artery. A 50-year-old man with previously diagnosed neurofibromatosis was admitted because of spontaneous rt-sided lumbago, paresthesia in rt-lower limb and severe anemia. Angiographic studies, CT and MRI revealed pseudo-aneurysm of bilateral lumbar arteries, which ruptured into the psoas muscle. Both arteries were ligated and hematoma was removed. The pathogenesis of the spontaneous rupture is discussed.