Greatly increased numbers of histamine cells in human narcolepsy with cataplexy

OBJECTIVE

To determine whether histamine cells are altered in human narcolepsy with cataplexy and in animal models of this disease.

METHODS

Immunohistochemistry for histidine decarboxylase (HDC) and quantitative microscopy were used to detect histamine cells in human narcoleptics, hypocretin (Hcrt) receptor-2 mutant dogs, and 3 mouse narcolepsy models: Hcrt (orexin) knockouts, ataxin-3-orexin, and doxycycline-controlled-diphtheria-toxin-A-orexin.

RESULTS

We found an average 64% increase in the number of histamine neurons in human narcolepsy with cataplexy, with no overlap between narcoleptics and controls. However, we did not see altered numbers of HDC cells in any of the animal models of narcolepsy.

INTERPRETATION

Changes in histamine cell numbers are not required for the major symptoms of narcolepsy, because all animal models have these symptoms. The histamine cell changes we saw in humans did not occur in the 4 animal models of Hcrt dysfunction we examined. Therefore, the loss of Hcrt receptor-2, of the Hcrt peptide, or of Hcrt cells is not sufficient to produce these changes. We speculate that the increased histamine cell numbers we see in human narcolepsy may instead be related to the process causing the human disorder. Although research has focused on possible antigens within the Hcrt cells that might trigger their autoimmune destruction, the present findings suggest that the triggering events of human narcolepsy may involve a proliferation of histamine-containing cells. We discuss this and other explanations of the difference between human narcoleptics and animal models of narcolepsy, including therapeutic drug use and species differences.

Abnormal signal intensities of the seminal vesicles in a screening population

PURPOSE

To investigate the incidence of abnormal signal hyperintensity on T1-weighted magnetic resonance imaging (MRI) of the seminal vesicles in a screening population in order to compare clinical indicators between subjects with and without signal abnormality.

MATERIALS AND METHODS

Signal intensity of the seminal vesicles on T1-weighted images and clinical examinations were investigated in 3570 examinations of 1865 male subjects (mean age 54.8 years, range 23-86 years at the first examination).

RESULTS

Abnormal signal hyperintensity was observed at least once in 32 subjects (1.7%). Subjects with the abnormality were significantly older (average age with and without the abnormality, 64.1 vs. 54.6, respectively, P < 0.001), and the incidence of abnormality increased with increasing age (0% for the age group <40, 0.3% for 40-49, 1.3% for 50-59, 2.9% for 60-69, 5.9% for 70-79, and 10.1% for >80). No significant difference was found in clinical indicators except for serum creatinine (1.10 vs. 0.84 mg/dL, P < 0.001). Of 12 subjects with abnormal signal intensity and follow-up data, the finding persisted on the same side for at least 11 months in seven subjects (58%).

CONCLUSION

Abnormal signal intensity of the seminal vesicles was observed in 1.7% of screening population, and the imaging finding in isolation is unlikely to have clinical significance.

Histamine synthesis is required for granule maturation in murine mast cells

Mast cells are the major sources of histamine, which is released in response to immunological stimulations. The synthesis of histamine is catalyzed by histidine decarboxylase (HDC). Previous studies have shown that Hdc(-/-) mast cells exhibit aberrant granule morphology with severely decreased granule content. Here, we investigated whether the histamine synthesized in mast cells regulates the granule maturation of murine mast cells. Several genes, including those encoding granule proteases and enzymes involved in heparin biosynthesis, were downregulated in Hdc(-/-) peritoneal mast cells. Impaired granule maturation was also found in Hdc(-/-) BM-derived cultured mast cells when they were cocultured with fibroblasts in the presence of c-kit ligand. Exogenous application of histamine and several H4 receptor agonists restored the granule maturation of Hdc(-/-) cultured mast cells. However, the maturation of granules was largely normal in Hrh4(-/-) peritoneal mast cells. Depletion of cellular histamine with tetrabenazine, an inhibitor of vesicular monoamine transporter-2, did not affect granule maturation. In vivo experiments with mast cell deficient Kit(W) /Kit(W-v) mice indicated that the expression of the Hdc gene in mast cells is required for granule maturation. These results suggest that histamine promotes granule maturation in mast cells and acts as an proinflammatory mediator.

Optimal treatment for spinal cord injury associated with cervical canal stenosis (OSCIS): a study protocol for a randomized controlled trial comparing early versus delayed surgery

Background

The optimal management of acute cervical spinal cord injury (SCI) associated with preexisting canal stenosis remains to be established. The objective of this study is to examine whether early surgical decompression (within 24 hours after admission) would result in greater improvement in motor function compared with delayed surgery (later than two weeks) in cervical SCI patients presenting with canal stenosis, but without bony injury.

Methods/design

OSCIS is a randomized, controlled, parallel-group, assessor-blinded, multicenter trial. We will recruit 100 cervical SCI patients who are admitted within 48 hours of injury (aged 20 to 79 years; without fractures or dislocations; American Spinal Injury Association (ASIA) grade C; preexisting spinal canal stenosis). Patients will be enrolled from 36 participating hospitals across Japan and randomly allocated in a 1:1 ratio to either early surgical decompression (within 24 hours after admission) or delayed surgery following at least two weeks of conservative treatment. The primary outcomes include: 1) the change from baseline to one year in the ASIA motor score; 2) the total score of the Spinal Cord Independence Measure and 3) the proportion of patients who are able to walk without human assistance. The secondary outcomes are: 1) the health-related quality of life as measured by the Medical Outcomes Study Short Form 36 and the EuroQol 5 Dimension; 2) the Neuropathic Pain Symptom Inventory and 3) the walking status as evaluated with the Walking Index for Spinal Cord Injury II. The analysis will be on an intention-to-treat basis. The primary analysis will be a comparison of the primary and secondary outcomes one year after the injury.

Discussion

The results of this study will provide evidence of the potential benefit of early surgical decompression compared to the current ‘watch and wait’ strategy.

Trial registration

UMIN000006780; NCT01485458

Histamine modulation of acute nociception involves regulation of Nav 1.8 in primary afferent neurons in mice

AIMS

To explore the role of histamine in acute pain perception and its possible mechanisms.

METHODS

Pain-like behaviors induced by four types of noxious stimuli (hot-plate, tail-pressure, acetic acid, and formalin) were accessed in mice. Nav 1.8 expression and functions in primary afferent neurons were compared between histidine decarboxylase knockout (HDC(-/-) ) mice and their wild-types.

RESULTS

HDC(-/-) mice, lacking in endogenous histamine, showed elevated sensitivity to all these noxious stimuli, as compared with the wild-types. In addition, a depletion of endogenous histamine with α-fluoromethylhistidine (α-FMH), a specific HDC inhibitor, or feeding mice a low-histamine diet also enhanced nociception in the wild-types. Nav 1.8 expression in primary afferent neurons was increased both in HDC(-/-) and in α-FMH-treated wild-type mice. A higher Nav 1.8 current density, a lower action potential (AP) threshold, and a higher firing rate in response to suprathreshold stimulation were observed in nociception-related small DRG neurons of HDC(-/-) mice. Nav 1.8 inhibitor A-803467, but not TTX, diminished the hyperexcitability and blocked repetitive AP firing of these neurons.

CONCLUSION

Our results indicate that histamine participates in acute pain modulation in a dose-related manner. The regulation of Nav 1.8 expression and the excitability of nociceptive primary afferent neurons may be involved in the underlying mechanisms.

Supplementary motor area stimulation for Parkinson disease

Objective:

To explore the efficacy and stimulation frequency dependence of repetitive transcranial magnetic stimulation (rTMS) over the supplementary motor area (SMA) in Parkinson disease (PD).

Methods:

In this randomized, double-blind, sham-controlled, multicenter study with a parallel design, a weekly intervention was performed 8 times. The effects were monitored up to 20 weeks. By central registration, participants were assigned to 1 of 3 arms of the study: low-frequency (1-Hz) rTMS, high-frequency (10-Hz) rTMS, and realistic sham stimulation. The primary end point was the score change of the Unified Parkinson's Disease Rating Scale (UPDRS) part III from the baseline. Several nonmotor symptom scales such as the Hamilton Rating Scale for Depression, apathy score, and nonmotor symptoms questionnaire were defined as secondary end points.

Results:

Of the 106 patients enrolled, 36 were allocated to 1-Hz rTMS, 34 to 10-Hz rTMS, and 36 to realistic sham stimulation. Results show 6.84-point improvement of the UPDRS part III in the 1-Hz group at the last visit of the 20th week. Sham stimulation and 10-Hz rTMS improved motor symptoms transiently, but their effects disappeared in the observation period. Changes in nonmotor symptoms were not clear in any group. No severe adverse event was reported.

Conclusions:

The 1-Hz rTMS over the SMA was effective for motor, but not nonmotor, symptoms in PD.

Level of evidence:

This study provides Class I evidence that 1-Hz rTMS over the SMA is effective for motor symptoms in PD.

An open trial of long-term testosterone suppression in spinal and bulbar muscular atrophy

INTRODUCTION

We investigated the long-term effects of leuprorelin on leg-muscle strength in spinal and bulbar muscular atrophy (SBMA). We hypothesized that testosterone suppression by leuprorelin would prevent the progression of muscle weakness.

METHODS

In a prospective, long duration, open trial, 16 SBMA patients underwent medical castration with leuprorelin for 3.5 years. Chlormadinone was coadministered initially to prevent a testosterone surge. The strength of knee extension and flexion were quantitated using a torque machine.

RESULTS

Our hypothesis was rejected. The leg strength measures decreased significantly with the mean reduction of 22.3-27.8%. In a post hoc analysis, the leg strength of 4 patients with higher pretreatment baseline total testosterone levels and short disease duration of 1-6 years were stronger at baseline and decreased by only 12.3-15.7% after treatment.

CONCLUSIONS

Leuprorelin was not effective in this small long-term treatment trial in SBMA. The possibility that earlier treatment might be beneficial may deserve further study.

Chronic h1-antihistamine treatment increases seizure susceptibility after withdrawal by impairing glutamine synthetase

AIM

To investigate the effect of chronic H1-antihistamine treatment on seizure susceptibility after drug withdrawal in nonepileptic rats and to further study its relation to glutamine synthetase (GS), which is the key enzyme for glutamate metabolism and gamma aminobutyric acid (GABA) synthesis.

METHODS

After drug withdrawal from a 2-week treatment with diphenhydramine or pyrilamine, seizure susceptibility was determined by amygdaloid kindling or pentylenetetrazol model; meanwhile, the GS expression or activity was analyzed. The glutamine, glutamate, and GABA contents were measured by high-performance liquid chromatography.

RESULTS

Seizure susceptibility significantly increased in amygdaloid kindling and pentylenetetrazol model 10 days after drug withdrawal from a 2-week treatment with H1-antihistamines. Meanwhile, GS activity and expression in the cortex or hippocampus decreased simultaneously with a marked decline of glutamine and GABA content. Comparable inhibition of GS activity by methionine sulfoximine was also sufficient to increase the susceptibility, while supplementation with glutamine reversed the high susceptibility 10 days after diphenhydramine withdrawal. Moreover, the seizure susceptibility increased 10 days after diphenhydramine withdrawal in wild-type mice but not in histidine decarboxylase knockout mice, which lack histamine.

CONCLUSIONS

Chronic H1-antihistamine treatment produces long-lasting increase in seizure susceptibility in nonepileptic rodents after drug withdrawal and its mechanism involves impairment of GS through blocking the action of histamine.

Meandering main pancreatic duct as a relevant factor to the onset of idiopathic recurrent acute pancreatitis

Background

Meandering main pancreatic duct (MMPD), which comprises loop type and reverse-Z type main pancreatic duct (MPD), has long been discussed its relation to pancreatitis. However, no previous study has investigated its clinical significance. We aimed to determine the non-biased prevalence and the effect of MMPD on idiopathic pancreatitis using non-invasive magnetic resonance (MR) technique.

Methods and Findings

A cross-sectional study performed in a tertiary referral center. The study enrolled 504 subjects from the community and 30 patients with idiopathic pancreatitis (7 acute, 13 chronic, and 10 recurrent acute). All subjects underwent MR scanning and medical examination. MMPD was diagnosed when the MPD in the head of pancreas formed two or more extrema in the horizontal direction on coronal images of MR cholangiopancreatography, making a loop or a reverse-Z shaped hairpin curves and not accompanied by other pancreatic ductal anomaly. Statistical comparison was made among groups on the rate of MMPD including loop and reverse-Z subtypes, MR findings, and clinical features. The rate of MMPD was significantly higher for all idiopathic pancreatitis/idiopathic recurrent acute pancreatitis (RAP) (20%/40%; P<0.001/0.0001; odds ratio (OR), 11.1/29.0) than in the community (2.2%) but was not higher for acute/chronic pancreatitis (14%/8%; P = 0.154/0.266). Multiple logistic regression analysis revealed MMPD to be a significant factor that induces pancreatitis/RAP (P<0.0001/0.0001; OR, 4.01/26.2). Loop/reverse-Z subtypes were found more frequently in idiopathic RAP subgroup (20%/20%; P = 0.009/0.007; OR, 20.2/24.2) than in the community (1.2%/1.0%). The other clinical and radiographic features were shown not associated with the onset of pancreatitis.

Conclusions

MMPD is a common anatomical variant and might be a relevant factor to the onset of idiopathic RAP.

Pathophysiologic role of histamine: evidence clarified by histidine decarboxylase gene knockout mice

The role of histamine in various murine disease models has been clarified using histidine decarboxylase gene knockout mice. The mice were generated using conventional gene-targeting methods. Studies, including ours, using knockout mice have shown that the activity of histamine is not limited to allergic, peptic and neurologic functions as in the old paradigm, but extends to other processes related to wound healing, circulatory disease, immunology, oncology and infectious disease. The recent observation of the activity of newly cloned histamine receptors and a pathophysiologic effect of histamine has dramatically expanded our understanding of the scope of histamine function.

Inverse association between the existence of coronary artery disease and progression of abdominal aortic aneurysm

OBJECTIVES

A strong degree of co-existence between coronary artery disease (CAD) and abdominal aortic aneurysm (AAA) is widely acknowledged, however, it remains to be elucidated whether the existence of CAD is associated with an accelerated expansion rate of AAA. Also, the relationship between preoperative CAD and postoperative major adverse cardiovascular events (MACE) has not been examined in Japanese patients. The aim of this study was to investigate the deleterious effects of CAD on the progression of AAA and the onset of postoperative MACE after elective AAA repair.

METHODS AND RESULTS

A retrospective cohort study of 665 consecutive Japanese patients who underwent elective surgical repair for infrarenal AAA at 2 high-volume Tokyo hospitals from 2003 through 2010 was performed. Preoperative CAD was shown to be a significant determinant of postoperative MACE (HR 2.29; 95%CI, 1.12-4.66; p=0.02). In the analysis of 510 patients for whom there were at least 2 follow-up CT scans of the size of their AAA before repair, the existence of CAD was shown to be inversely associated with the accelerated expansion rate of AAA.

CONCLUSION

This study on the patients undergone elective repair for infrarenal AAA identified an inverse association between the existence of CAD and progression of AAA as well as the significant impact of preoperative CAD on the occurrence of postoperative MACE after elective AAA repair.

Arrhythmogenic effect of sympathetic histamine in mouse hearts subjected to acute ischemia

The role of histamine as a newly recognized sympathetic neurotransmitter has been presented previously, and its postsynaptic effects greatly depended on the activities of sympathetic nerves. Cardiac sympathetic nerves become overactivated under acute myocardial ischemic conditions and release neurotransmitters in large amounts, inducing ventricular arrhythmia. Therefore, it is proposed that cardiac sympathetic histamine, in addition to norepinephrine, may have a significant arrhythmogenic effect. To test this hypothesis, we observed the release of cardiac sympathetic histamine and associated ventricular arrhythmogenesis that was induced by acute ischemia in isolated mouse hearts. Mast cell-deficient mice (MCDM) and histidine decarboxylase knockout (HDC(-/-)) mice were used to exclude the potential involvement of mast cells. Electrical field stimulation and acute ischemia-reperfusion evoked chemical sympathectomy-sensitive histamine release from the hearts of both MCDM and wild-type (WT) mice but not from HDC(-/-) mice. The release of histamine from the hearts of MCDM and WT mice was associated with the development of acute ischemia-induced ventricular tachycardia and ventricular fibrillation. The incidence and duration of induced ventricular arrhythmias were found to decrease in the presence of the selective histamine H(2) receptor antagonist famotidine. Additionally, the released histamine facilitated the arrhythmogenic effect of simultaneously released norepinephrine. We conclude that, under acute ischemic conditions, cardiac sympathetic histamine released by overactive sympathetic nerve terminals plays a certain arrhythmogenic role via H(2) receptors. These findings provided novel insight into the pathophysiological roles of sympathetic histamine, which may be a new therapeutic target for acute ischemia-induced arrhythmias.

Comparison of CT findings of biliary tract changes with autoimmune pancreatitis and extrahepatic bile duct cholangiocarcinoma

PURPOSE

To retrospectively evaluate criteria for differentiating biliary tract changes in autoimmune pancreatitis (AIP-BTC) from extrahepatic cholangiocarcinoma (ECCA) based on CT findings and to determine predictors for differentiation between the two disorders.

MATERIALS AND METHODS

CT findings of 22 patients with AIP-BTC and 45 patients with ECCA, both with positive CT findings in the biliary system, were retrospectively assessed. The images were assessed for presence of biliary obstruction, diameter of the maximally dilated biliary duct, maximum thickness of the involved duct, presence of masses inside or around the involved ducts, lengths of the biliary lesions, concentricity of wall thickening, multifocality of the lesion, and degree of lesion enhancement.

RESULTS

Compared with AIP-BTC, ECCA was significantly more frequently associated with biliary obstruction (p = 0.0037), shorter lengths of the biliary lesions (p = 0.0036), and masses (p < 0.001). No significant differences were found for other items.

CONCLUSION

Presence of obstructive dilatation of the bile ducts and intraluminal or peri-ductal masses and length of the thickened wall may help differentiate between AIP-BTC and ECCA.

Sympathoexcitation by brain oxidative stress mediates arterial pressure elevation in salt-induced chronic kidney disease

Hypertension is very prevalent in chronic kidney disease and critical for its prognosis. Sympathoexcitation and oxidative stress have been demonstrated to be involved in chronic kidney disease. We have shown previously that sympathoexcitation by brain oxidative stress mediates arterial pressure elevation in the salt-sensitive hypertension model, Dahl salt-sensitive rats. Thus, we investigated whether sympathoexcitation by excessive brain oxidative stress could contribute to arterial pressure elevation in salt-induced chronic kidney disease model rats. Young (3-week-old) male Sprague-Dawley rats were randomly assigned to a uninephrectomy or sham operation and then subjected to either a normal salt (0.5%) or high-salt (8.0%) diet for 4 weeks. The young salt-loaded uninephrectomized rats exhibited sympathoexcitation, hypertension, and renal injury, proteinuria and global glomerulosclerosis together with tubulointerstitial damage. Under urethane anesthesia and artificial ventilation, renal sympathetic nerve activity, arterial pressure, and heart rate decreased to a greater degree in the salt-loaded uninephrectomized rats than in the nonsalt-loaded uninephrectomized rats and the salt-loaded or nonsalt-loaded sham-operated rats, when Tempol, a membrane-permeable superoxide dismutase mimetic, was infused acutely into the lateral cerebral ventricle. Oxidative stress in the hypothalamus, measured by lucigenin chemiluminescence, was also significantly greater. Furthermore, in the salt-loaded uninephrectomized rats, antioxidant treatment with chronic intracerebroventricular Tempol decreased sympathetic nerve activity and arterial pressure, which, in turn, led to a decrease in renal damage. Similar effects were elicited by treatment with oral moxonidine, the central sympatholytic agent. In conclusion, sympathoexcitation by brain oxidative stress may mediate arterial pressure elevation in salt-induced chronic kidney disease.

Tests for serum levels of trefoil factor family proteins can improve gastric cancer screening

BACKGROUND & AIMS

Improving methods for early detection of gastric cancer could reduce mortality. Measurements of serum pepsinogen levels have been used for screening in Japan without satisfactory levels of sensitivity or specificity. Trefoil factor family (TFF) proteins (TFF1, TFF2, and TFF3) are small and stable molecules secreted by the mammalian gastrointestinal tract. Foveolar hyperplasia, spasmolytic polypeptide (TFF2)-expressing metaplasia, and intestinal metaplasia are histologic changes observed in patients with atrophic gastritis; they express TFF1, TFF2, and TFF3, respectively. We investigated whether serum levels of TFF can be used as markers for gastric cancer screening.

METHODS

Serum was collected from 183 patients with gastric cancer and 280 healthy individuals without cancer. Serum levels of anti-Helicobacter pylori immunoglobulin G, pepsinogen I, pepsinogen II, TFF1, TFF2, and TFF3 were measured by enzyme-linked immunosorbent assay and associated with gastric cancer.

RESULTS

Using a cutoff of 3.6 ng/mL, the level of TFF3 was significantly increased in serum samples from patients with cancer (odds ratio, 18.1; 95% confidence interval, 11.2-29.2); using this test, patients with cancer were identified with 80.9% sensitivity and 81.0% specificity. The test for TFF3 had a significantly higher odds ratio than that for pepsinogen. A test for the combination of TFF3 and pepsinogen had better results than the test for only pepsinogen.

CONCLUSIONS

Serum levels of TFF3 are a better marker of gastric cancer than pepsinogen; a test for the combined levels of serum pepsinogen and TFF3 could improve gastric cancer screening.

Pancreas divisum as a predisposing factor for chronic and recurrent idiopathic pancreatitis: initial in vivo survey

BACKGROUND

It is a controversial issue whether pancreas divisum (PD) induces pancreatitis. All previous studies have investigated this issue based on endoscopic procedures, which inevitably involve a selection bias.

OBJECTIVES

To determine the unbiased prevalence rate of PD in a community population and to investigate the effect of PD on idiopathic pancreatitis using a non-invasive magnetic resonance (MR) technique.

DESIGN

Cross-sectional study.

PATIENTS

The study enrolled 504 subjects from the community who participated in the medical check-up programme and 46 patients with idiopathic pancreatitis (8 acute, 23 chronic, 15 recurrent) extracted from 70,122 consecutive MR studies performed at an academic tertiary care hospital.

INTERVENTIONS

All subjects underwent magnetic resonance (MR) scanning and medical examination.

MAIN OUTCOME MEASURES

Statistical comparison between subjects from the community and patients with idiopathic pancreatitis was made for the rate of PD (and its subtypes: classical PD, PD with absent ventral duct, and incomplete PD), MR findings, and clinical features.

RESULTS

Multiple logistic regression analysis revealed PD as a significant factor that induces pancreatitis (OR 23.4; p<0.0001). The PD rate was significantly higher for all/chronic/recurrent idiopathic pancreatitis patients (35%/43%/33%; p<0.001 for all) than for subjects in the community group (2.6%), but was not higher for acute pancreatitis (13%; p=0.357). All PD subtypes were indicated to induce idiopathic pancreatitis but showed different associations with each onset type of pancreatitis.

CONCLUSIONS

This is the first study to describe the prevalence of PD and PD subtypes in a community population and their association with idiopathic pancreatitis in vivo based on the findings of non-invasive MR and with minimal selection bias. It is concluded that PD should be considered a predisposing factor for chronic and recurrent pancreatitis.

Histamine synthesis and lessons learned from histidine decarboxylase deficient mice

This chapter summarizes the information about the transcriptional regulation of histidine decarboxylase (HDC), which is the catabolic enzyme of histamine synthesis, and the activity of histamine in vivo as clarified using HDC gene deficient mice (HDC-KO). The research of the regulatory mechanism of histamine synthesis has been focused on transcriptional and posttranslational aspects. The generation ofHDC-KO mice clarified several new pathophysiological functions of histamine. It is now recognized that the activity of histamine is not limited to allergic, peptic and neurological functions as in the old paradigm, but extends to other fields such as cardiology, immunology and infectious diseases. Therefore, this chapter will focus on these newly revealed functions of histamine. For example, histamine was known to be involved in the effector phase of allergic responses, but a role has now been shown in the sensitization phases and in innate immunity. In the allergic bronchial asthma model using HDC-KO mice it was found that histamine positively controls eosinophilia, but not bronchial hypersensitivity. The effect on eosinophils was afterwards shown to be mediated through the activity of the histamine H4 receptor. The recent advances in the understanding of histamine synthesis and the activity of HDC have dramatically expanded our understanding of the scope of histamine function.